FINAL PROGRAM & PROCEEDINGS 2 Welcome to the Fairmont Orchid for Spine Across the Sea!

SPINE ACROSS THE SEA July 5-8, 2021 The Fairmont Orchid Kohala Coast, Big Island Hawaii USA

A Joint Providership by the North American Spine Society and the Japanese Society for Spine Surgery and Related Research

What a great place to have a meeting. This oceanfront resort NASS PROGRAM CHAIR offers world-class golf, a fi tness center, 10-court tennis Patrick C. Hsieh, MD, MS pavilion, award-winning spa, and 10,000 square foot pool, in addition to six restaurants. NASS PROGRAM CO-CHAIR Charles A. Reitman, MD You’ll have plenty of time every morning and evening to enjoy all the resort amenities. JSSR PROGRAM CHAIR Masaya Nakamura, MD, PhD In the afternoons, faculty will provide engaging surgical spine symposia and scientifi c podium presentations on adult spinal PLANNING COMMITTEE deformity, minimally invasive spine surgery, cervical stenosis, Patrick C. Hsieh, MD, MS OPLL, biologics, trauma and spondylolisthesis. Overall Chair, NASS Yukihiro Matsuyama, MD, PhD Regrettably, the Japanese Society for Spine Surgery and President and Overall Chair, JSSR Related Research chairpersons and faculty will present virtually because of the current COVID-19 situation in Japan. JSSR ORGANIZING COMMITTEE Hirotaka Haro, MD, PhD Make sure to attend the Tuesday and Wednesday evening Vice President, JSSR Fireside Chats on the beach, 6-7:30 p.m. Theses chats are Masashi Neo, MD a great way to relax with colleagues and have informal Kazuhiro Hasegawa, MD, PhD discussions about osteobiologics as well as the evaluation Kazuhiro Chiba, MD, PhD and adoption of novel technologies. There will be a bento Masahiko Watanabe, MD, PhD box dinner and beer, wine, and soft drinks served. You must register for each fi reside chat. Thank you for att ending Spine Across the Sea! Have a great week.

Meeting Information 3

Continuing Medical Education Credit Learning Objectives This activity has been planned and implemented in Upon completion of this meeting, participants will gain accordance with the Essentials and Standards of the strategies to: Accreditation Council for Continuing Medical Education • Promote discussion of new scientifi c developments (ACCME). The North American Spine Society is and best practices within spine care organizations; accredited by the ACCME to provide continuing medical • Demonstrate the application of current techniques, education for physicians and takes responsibility for procedures and research; the content, quality and scientifi c integrity of this CME • Practice evidence- and value-based medicine relative activity. to spine care; • Provide an environment for the exchange of ideas in The North American Spine Society designates this live spine care with experts and peers from around the activity for a maximum of 18.5 AMA PRA Category globe; 1 CreditsTM. Physicians should claim only the credit • Provide opportunities to strengthen professional commensurate with the extent of their participation in relationships worldwide. the activity.

The American Medical Association has determined Meeting Format that physicians not licensed in the U.S. to participate in Enjoy a blended meeting format: register and attend this CME activity are eligible for AMA PRA Category 1 the meeting in-person in Hawaii or attend virtually from TM Credits . home or offi ce. All sessions will stream live except for Fireside Chats in HST (Hawaii Standard Time) and JST The American Academy of Physician Assistants (Japan Standard Time). (AAPA) accepts Category 1 credit from AOACCME, prescribed credit from the American Academy of Family Due to the COVID-19 pandemic, all JSSR chairpersons TM Physicians (AAFP) and AMA PRA Category 1 CME and faculty are presenting virtually. credit for the Physician’s Recognition Award from organizations, such as NASS, accredited by the ACCME. Att endee and Exhibitor Registration Each state has different requirements for nurses, Hours (HST) physical therapists and other nonphysician providers; please contact the credit granting organization for its Monday, July 5 ...... 10:30 a.m.–6:00 p.m. requirements. Tuesday, July 6 ...... 11:30 a.m.–6:00 p.m. Wednesday, July 7 ...... 11:30 a.m.–6:00 p.m. For credit that may be acceptable to state medical Thursday, July 8 ...... 11:30 a.m.–4:30 p.m. associations, specialty societies or state boards for medical licensure, please contact those organizations for their requirements.

CME Certiﬁ cates After the meeting, evaluations will be submitted electronically and CME certifi cates will be printed directly from our website at www.spine.org/CME. Contact [email protected] with questions. Forgotten passwords can be requested from the login page by using the email address used to register for the conference. Meeting Information 4

Technical Exhibition About NASS Head to Grand Ballroom III to experience fi rst-hand The North American Spine Society (NASS) is a technology, products and services from vendors who multidisciplinary organization with approximately 8,000 can help you manage your professional goals and members in North America and abroad. The membership strategic objectives. consists of orthopedic surgeons, neurosurgeons, physiatrists, other medical/interventional physicians and Technical Exhibition Hours (HST) affi liated healthcare professionals involved in spine care. Monday, July 5 ...... 11:45 a.m.–4:00 p.m. The leading multidisciplinary organization in the fi eld of Tuesday, July 6 ...... 11:45 a.m.–5:00 p.m. spinal disorders, NASS’ mission is to foster the delivery of Wednesday, July 7 ...... 11:45 a.m.–5:00 p.m. quality spine care. About JSSR Spine Across the Sea Exhibitors The Japanese Society for Spine Surgery and Related Medtronic Research (JSSR) is the largest Japanese organization Medtronic.com representing members in the fi eld of spine and spinal cord disorders. JSSR has more than 3,600 members, mainly Attend our Fireside Chats Tuesday and Wednesday orthopedic surgeons. They hold an annual meeting and evening. Ask at Registration! publish its offi cial journal to promote basic research and clinical innovation. We believe in applying the full power of technology for better patient outcomes. In addition to alleviating pain, restoring health, and extending lives, we work Disclaimer in partnership with others to create seamless, more The material presented at Spine Across the Sea is effi cient care. Learn how we’re taking healthcare made available by the North American Spine Society for Further, Together at Medtronic.com. Visit our booth to educational purposes only. The material is not intended learn more about our innovative solutions. to represent the only, nor necessarily the best, method or procedure appropriate for the medical situations Biologica Technologies discussed; rather, it is intended to present an approach, view, statement or opinion of the faculty which may be http://www.biologicatechnologies.com helpful to others who face similar situations. Biologica Technologies is a company fully dedicated to NASS disclaims any and all liability for injury or other improving patients’ lives and the health care providers’ damages to any individual attending the meeting and for experience through innovative biologic solutions. Our all claims which may arise out of the use of the techniques core, proprietary technology, ProteiOS® growth factor, demonstrated therein by such individuals, whether these possesses the largest amount of non-recombinant claims shall be asserted by physicians or any other osteoinductive, angiogenic and mitogenic growth person. factors on the market today. On occasion, changes in program content or faculty may occur after the Preliminary Program has been distributed. This Final Program contains confi rmed program content, faculty and presenters. Any further changes will be announced at the beginning of the session. Meeting-at-a-Glance 5

Monday, July 5 Tuesday, July 6 (HST, US) (JST, Tokyo)

10:30 a.m.-6:00 p.m. Registration/Speaker Information Center

11:45 a.m.-4:00 p.m. Technical Exhibition

11:55 a.m.-12:00 p.m. 6:55-7:00 a.m. Opening Remarks

12:00-1:30 p.m. 7:00-8:30 a.m. Abstract Session: Outcomes Following Cervical Spine Surgery

1:30-2:00 p.m. 8:30-9:00 a.m. Networking Break/Technical Exhibition

2:00-3:30 p.m. 9:00-10:30 a.m. Symposium: Cervical Stenosis and Ossifi cation of Posterior Longitudinal Ligament (OPLL) with Myelopathy

3:30-4:00 p.m. 10:30-11:00 a.m Networking Break/Technical Exhibition

4:00-5:30 p.m. 11:00 a.m.-12:30 p.m. Abstract Session: Complications

5:30 p.m. 12:30 p.m. General Meeting Adjourns

Tuesday, July 6 Wednesday, July 7 (HST, US) (JST, Tokyo) 11:30 a.m.-6:00 p.m. Registration/Speaker Information Center

11:45 a.m.-5:00 p.m. Technical Exhibition

11:55 a.m.-12:00 p.m. 6:55-7:00 a.m. Opening Remarks

12:00-1:30 p.m. 7:00-8:30 a.m. Symposium: Minimally Invasive Spine Surgery

1:30-2:00 p.m 8:30-9:00 a.m. Networking Break/Technical Exhibition

2:00-3:00 p.m. 9:00-10:00 a.m. Abstract Session: Cervical Spine

3:00-4:30 p.m. 10:00-11:30 a.m. Symposium: Adult Spinal Deformity

4:30-5:00 p.m. 11:30 a.m.-12:00 p.m. Networking Break/Technical Exhibition

5:00-6:00 p.m. 12:00-1:00 p.m. Virtual Abstract Session*: New Concepts in Imaging

6:00 p.m. 1:00 p.m General Meeting Adjourns

6:00-7:30 p.m. Ticketed Event: Fireside Chat at the Beach Osteobiologics: How Do You Choose Biologics in Your Practice and What Works for You?

Wednesday, July 7 Thursday, July 8 (HST, US) (JST, Tokyo) 11:30 a.m.-6:00 p.m. Registration/Speaker Information Center

11:45 a.m.-5:00 p.m. Technical Exhibition

11:55 a.m.-12:00 p.m. 6:55-7:00 a.m. Opening Remarks 12:00-1:30 p.m. 7:00-8:30 a.m. Symposium: Management of Spine Trauma and Spinal Cord Injury

1:30-2:00 p.m. 8:30-9:00 a.m. Networking Break/Technical Exhibition

2:00-3:00 p.m. 9:00-10:00 a.m. Abstract Session: Use of New Technology in Spine Care 3:00-4:30 p.m. 10:00-11:30 a.m. Symposium: Novel Technology and Biologics 4:30-5:00 p.m. 11:30 a.m.-12:00 p.m. Networking Break

5:00-6:00 p.m. 12:00-1:00 p.m. Virtual Abstract Session:* Deformity

6:00 p.m. 1:00 p.m. General Meeting Adjourns

6:00-7:30 p.m. Ticketed Event: Fireside Chat at the Beach How Do You Evaluate and Adopt Novel Technologies in Spine Surgery to Improve Outcomes and Minimize Complications?

* All presenters in this session are now virtual. The moderator will still be available in person during the live session to take questions from the in person and virtual audiences.

Thursday, July 8 Friday, July 9 (HST, US) (JST, Tokyo)

11:30 a.m.-4:30 p.m. Registration/Speaker Information Center

11:55 a.m.-12:00 p.m. 6:55-7:00 a.m. Opening Remarks

12:00-1:30 p.m. 7:00-8:30 a.m. Virtual Abstract Session:* Thoracolumbar Surgery

1:30-2:00 p.m. 8:30-9:00 a.m. Networking Break

2:00-3:00 p.m. 9:00-10:00 a.m. Abstract Session: Bone Health Considerations in Management of Spinal Disorders

3:00-4:30 p.m. 10:00-11:30 a.m. Symposium: Controversies and Debates in Management of Lumbar Degenerative Spondylolisthesis

4:30 p.m. 11:30 a.m. General Meeting Adjourns

* All presenters in this session are now virtual. The moderator will still be available in person during the live session to take questions from the in person and virtual audiences. All sessions will stream live except for ﬁ reside chats in HST (Hawaii Standard Time) and JST7 (Japan Standard Time). Due to the COVID-19 pandemic, all JSSR chairs and faculty are presenting virtually. *Virtual presenters denoted with a green asterisk.

Meeting Schedule Monday, July 5 (HST)/Tuesday, July 6 (JST)

1:30 a.m.-6:00 p.m. HST Registration/Speaker Information Center Grand Ballroom Foyer

11:45 a.m.-4:00 p.m. HST Technical Exhibition Grand Ballroom III

11:55 a.m.-12:00 p.m. HST / 6:55-7:00 a.m. JST Opening Remarks Grand Ballroom I & II Patrick C. Hsieh, MD, MS University of Southern California Spine Center, Dept. of Neurosurgery Charles A. Reitman, MD Medical University of South Carolina, Dept. of Orthopaedics Masaya Nakamura, MD, PhD* Keio University

12:00-1:30 p.m. HST / 7:00-8:30 a.m. JST Abstract Session: Outcomes Following Cervical Spine Surgery Grand Ballroom I & II Moderator: Edward J. Dohring, MD Spine Institute of Arizona

12:00–12:06 p.m. 1. More than 20 years follow up after cervical Toyama University, Department of Orthopaedic Surgery, Toyama, Japan laminoplasty FDA Device/Drug Status: This abstract does not discuss or include any Yoshiharu Kawaguchi, MD, PhD* applicable devices or drugs.

12:06–12:12 p.m. 2. Postoperative SVA >4 cm has no impact on neck 1Mayo Clinic, Rochester, MN, US; 2Mayo Clinic/Dept of Orthopedic pain scores after C2-T2 fusion for myelopathy: Surgery, Rochester, MN, US; 3Rothman Institute Thomas Jefferson Results from a multicenter cohort study University, Philadelphia, PA, US; 4Rothman Institute, Philadelphia, PA, US; 5Walter Reed National Military Medical Center, Bethesda, MD, US Harold I. Salmons, MD1; Zachariah Pinter, MD1; Joshua Kolz, MD, MS1; Ahmad N. Nassr, MD2; Bradford L. Currier, FDA Device/Drug Status: This abstract does not discuss or include any MD1; Brett A. Freedman, MD1; Benjamin D. Elder, MD, applicable devices or drugs. PhD1; Gregory D. Schroeder, MD3; Alexander R. Vaccaro, MD, PhD4; Scott Wagner, MD5; Ian D. Kaye, MD4; Arjun S. Sebastian, MD, MSc1

12:12–12:18 p.m. 3. Cervical alignment and distal junctional failure in 1Mayo Clinic, Rochester, MN, US; 2SUNY Downstate, Brooklyn, NY, posterior cervical fusion: A multicenter comparison of US; 3Northwell Health, New Hyde Park, NY, US; 4Mayo Clinic/Dept two surgical approaches of Orthopedic Surgery, Rochester, MN, US; 5Rothman Institute, Philadelphia, PA, US; 6Walter Reed National Military Medical Center, Zachariah Pinter, MD1; Arjun S. Sebastian, MD, MS1; Jad Bou Bethesda, MD, US Monsef, MD2; Daniel R. Bowles, MD3; Ashley Xiong, CCRC1; Bradford L. Currier, MD1; Ahmad N. Nassr, MD4; Brett A. FDA Device/Drug Status: This abstract does not discuss or include any Freedman, MD1; Mohamad Bydon, MD1; Benjamin D. Elder, applicable devices or drugs. MD, PhD1; Christopher K. Kepler, MD, MBA5; Alexander R. Vaccaro, MD, PhD5; Ian D. Kaye, MD5; Scott Wagner, MD6 Meeting Schedule 8 Monday, July 5 (HST)/Tuesday, July 6 (JST) *Virtual presenters denoted with a green asterisk.

12:18–12:24 p.m. 4. Change in postoperative intervertebral space West China Hospital, Sichuan University, Chengdu, China height and its impact on clinical and radiological FDA Device/Drug Status: This abstract does not discuss or include any outcomes after ACDF surgery with zero profile applicable devices or drugs. device Haimiti Abudouaini, MD

12:24–12:30 p.m. 5. Microendoscopic laminotomy versus 1Dokkyo Medical University Nikko Medical Center, Nikko, Tochigi, Japan; conventional laminoplasty for cervical spondylotic 2Brigham and Women’s Hospital, Dept of Orthopedic Surgery, Boston, MA, US; myelopathy: A 5 year follow up study 3Wakayama, Japan; 4Nagareyama Chuoh Hospital, Nagareyama, Chiba, Japan; 5Wakayama Medical University, Dept of Orthopaedic Surgery, Wakayama, Akihito Minamide, MD, PhD1 ; Andrew Simpson, MD2; * Japan Yasutsugu Yukawa, MD, PhD3; Hiroshi Hashizume, MD, PhD3; Yutaka Nohara, MD4; Hiroshi Yamada, MD, PhD5 FDA Device/Drug Status: This abstract does not discuss or include any applicable devices or drugs.

12:30–12:45 p.m. Discussion

12:45–12:51 p.m. 6. Physical and mental well-being improvements 1Osaka City University, Osaka, Japan; 2Dept. of Orthopaedic Surgery, Osaka after surgery for cervical spondylotic myelopathy City University, Graduate School of Medicine, Osaka, Japan; 3Ishikiriseiki Hospital, Higashiosaka, Japan; 4Osaka City University, Graduate School of Koji Tamai, MD1*; Akinobu Suzuki, MD, PhD1; Hidetomi Terai, MD, PhD2; Masatoshi Hoshino, MD2; Hiromitsu Medicine, Osaka, Japan Toyoda, MD, PhD1; Shinji Takahashi, MD1; Yusuke Hori, FDA Device/Drug Status: This abstract does not discuss or include any MD4; Akito Yabu, MD3; Hiroaki Nakamura, MD, PhD4 applicable devices or drugs.

12:51–12:57 p.m. 7. Moved to Cervical Stenosis and Ossification of Posterior Longitudinal Ligament (OPLL) with Myelopathy

12:57–1:03 p.m. 8. Residual neuropathic pain in postoperative 1Kitasato University, School of Medicine, Sagamihara, Japan; 2Tokyo Medical 3 patients for cervical ossification of posterior & Dental University, Tokyo, Japan; Department of Orthopaedic Surgery, Chiba 4 longitudinal ligament University Graduate School of Medicine, Chiba, Japan; Jichi Medical University, Tochigi, Japan; 5Toronto Western Hospital, Toronto, ON, Canada; 6Nagoya 1 2 Masayuki Miyagi, MD, PhD *; Toshitaka Yoshii, MD ; University Graduate School of Medicine, Department of Orthopedic Surgery, 3 3 Masao Koda, MD, PhD ; Takeo Furuya, MD, PhD ; Nagoya, Japan; 7Kitasato University, School of Medicine, Dept of Orthopaedic 4 5 Atsushi Kimura, MD, PhD ; Narihito Nagoshi, MD, PhD ; Surgery, Sagamihara, Kanagawa, Japan; 8Nagoya University Graduate School 6 7 Hiroaki Nakashima, MD ; Gen Inoue, MD, PhD ; Shiro of Medicine, Nagoya, Japan; 9Department of Orthopaedic Surgery, Jichi 8 9 Imagama, MD ; Katsushi Takeshita, MD, PhD ; Morio Medical University, Tochigi, Japan; 10Keio University School of Medicine, Tokyo, 10 11 Matsumoto, MD ; Atsushi Okawa, MD, PhD ; Masashi Japan; 11Bunkyo-Ku, Japan; 12Department of Orthopaedic Surgery, Faculty of 12 13 Yamazaki, MD, PhD ; Takaso Masashi, MD, PhD Medicine, University of Tsukuba, Tsukuba, Japan; 13Kitazato University, School of Medicine, Sagamihara-shi, Japan FDA Device/Drug Status: This abstract does not discuss or include any applicable devices or drugs.

1:03–1:09 p.m. 9. The impact of posterior cervical foraminotomy 1Hospital for Special Surgery, New York, NY, US; 2New York, NY, US on neck pain: A systematic review and meta- FDA Device/Drug Status: This abstract does not discuss or include any analysis applicable devices or drugs. Hikari Urakawa1*; Kosuke Sato, MD2; Avani S. Vaishnav, MBBS1; Bridget Jivanelli, MS, BA2; Catherine Himo Gang, MPH1; Sheeraz A. Qureshi, MD, MBA1 Meeting Schedule 9 Monday, July 5 (HST)/Tuesday, July 6 (JST) *Virtual presenters denoted with a green asterisk.

1:09–1:15 p.m. 10. Comparison of patient-reported postoperative Department of Orthopedics, West China Hospital, Sichuan University, dysphagia in patients undergoing one-level versus Chengdu, Sichuan, China two-level anterior cervical discectomy and fusion FDA Device/Drug Status: This abstract does not discuss or include any with the Zero-P Implant System applicable devices or drugs. Chengyi Huang, MD, PhD

1:15–1:30 p.m. Discussion

1:30-2:00 p.m. HST / 8:30-9:00 a.m. JST Networking Break/Technical Exhibition Grand Ballroom III

2:00-3:30 p.m. HST / 9:00-10:30 a.m. JST Symposium: Cervical Stenosis and Ossiﬁ cation of Posterior Longitudinal Ligament (OPLL) with Myelopathy Grand Ballroom I & II Moderators: Eeric Truumees, MD Ascension Texas Spine & Scoliosis Kazuhiro Chiba, MD, PhD* National Defense Medical College

Cervical stenosis with myelopathy is a leading cause of disability 2:25-2:35 p.m. HST / 9:25-9:35 a.m. JST worldwide. Cervical stenosis with ossifi cation of longitudinal Residual Neuropathic Pain in Postoperative Patients for ligament (OPLL) is a particular challenging problem as there Cervical Ossiﬁ cation of Posterior Longitudinal Ligament are increased perioperative surgical risks, including dural injury Masayuki Miyagi, MD, PhD* with CSF leak and eurological injury. In this symposium, faculty Kitasato University will address various approaches to treat cervical stenosis with myelopathy and OPLL, as well as present technical advances 2:35-2:45 p.m. HST / 9:35-9:45 a.m. JST and surgical nuances to improve perioperative outcomes of The Hyper-Angulated Screw/Plate Fixation Facilitates cervical spondylitic myelopathy and OPLL. Optimal Bone Purchase for Multilevel Cervical Anterior Fusion Masahiko Takahata, MD, PhD* Upon completion of this symposium, participants should gain Hokkaido University strategies to: • Recognize the advantages and limitations of different 2:45-2:55 p.m. HST / 9:45-9:55 a.m. JST approaches to treat cervical stenosis and OPLL; Debate for OPLL Treatments with Case Presentation • Evaluate and choose the optimal approach to improve Eeric Truumees, MD perioperative and long-term outcomes for patients with Ascension Texas Spine & Scoliosis cervical stenosis and OPLL with myelopathy; • Obtain technical and treatment pearls to treat patients with 2:55-3:05 p.m. HST / 9:55-10:05 a.m. JST cervical stenosis and OPLL with cervical myelopathy. Laminoplasty for OPLL Jeffrey C. Wang, MD Agenda University of Southern California Spine Center 2:00-2:05 p.m. HST / 9:00-9:05 a.m. JST Welcome and Introduction 3:05-3:15 p.m. HST / 10:05-10:15 a.m. JST Eeric Truumees, MD Laminectomy and Fusion for Cervical Myelopathy and OPLL Ascension Texas Spine & Scoliosis Patrick C. Hsieh, MD University of Southern California Spine Center, Dept. of Neurosurgery 2:05-2:15 p.m. HST / 9:05-9:15 a.m. JST Technical Modiﬁ cations and Clinical Outcomes of Expansive 3:15-3:25 p.m. HST / 10:15-10:25 a.m. JST Open-Door Laminoplasty Anterior Approach for Cervical Stenosis with and without Kazuhiro Chiba, MD, PhD* OPLL National Defense Medical College Jean-Jacques Abitbol, MD California Spine Group 2:15-2:25 p.m. HST / 9:15-9:25 a.m. JST More Than 20 Year Follow-Up after Cervical Laminoplasty 3:25-3:30 p.m. HST / 10:25-10:30 a.m. JST Yoshiharu Kawaguchi, MD, PhD* Questions and Discussion Toyama University

Meeting Schedule 10 Monday, July 5 (HST)/Tuesday, July 6 (JST) *Virtual presenters denoted with a green asterisk.

3:30-4:00 p.m. HST / 10:30-11:00 a.m. JST Networking Break/Technical Exhibition Grand Ballroom III

4:00-5:30 p.m. HST / 11:00 a.m.-12:30 p.m. JST Abstract Session: Complications Grand Ballroom I & II Moderator: William J. Sullivan, MD Vanderbilt University, Dept. of Physical Medicine and Rehabilitation

4:00–4:06 p.m. 11. Perioperative risk stratifi cation in elective 1San Francisco, CA, US; 2Jackson - PM&R, Miami, FL, US; 3California orthopaedic spine surgery: A systematic review Northstate University, Elk Grove, CA, US; 4UCSF Dept. of Orthopaedic Surgery, San Francisco, CA, US Hao-Hua Wu, MD1*; Andrew Logan, MD2; Steven Wright, BS3; Lionel N. Metz, MD4 FDA Device/Drug Status: This abstract does not discuss or include any applicable devices or drugs.

4:06–4:12 p.m. 12. The performance of frailty in predictive 1USC - Neurosurgery Dept, Los Angeles, CA, US; 2Keck School of Medicine, modeling of short-term outcomes in the surgical University of Southern California, Los Angeles, CA, US; 3Department of management of metastatic tumors to the spine Orthopedic Surgery, Keio University School of Medicine, Los Angeles, CA, US; 4Department of Neurological Surgery, Los Angeles, CA, US; 5USC Spine 2 ; Joshua Bakhsheshian, MD, Shane Shahrestani, MS * Center and Dept of Neurosurgery, Los Angeles, CA, US; 6USC Spine Center, MS1; Zorica Buser, PhD2; Raymond J. Hah, MD3; Patrick Los Angeles, CA, US C. Hsieh, MD, MS4; John C. Liu, MD5; Jeffrey C. Wang, MD6 FDA Device/Drug Status: This abstract does not discuss or include any applicable devices or drugs.

4:12–4:18 p.m. 13. Acute colonic pseudo-obstruction (Ogilvie 1UCLA, Santa Monica, CA, US; 2University of California, Los Angeles, Los Syndrome) following primary spinal fusion: An Angeles, CA, US; 3Los Angeles, CA, US; 4Santa Monica, CA, US analysis of outcomes and risk factors from 2005 FDA Device/Drug Status: This abstract does not discuss or include any to 2014 applicable devices or drugs. Don Y. Park, MD1; Clark J. Chen, MD2; Peter P. Hsiue, MD3; Elizabeth L. Lord, MD4; Alexandra Stavrakis, MD4

4:18–4:24 p.m. 14. Sarcopenia predicts perioperative adverse Houston Methodist Hospital, Houston, TX, US events following complex revision surgery for the FDA Device/Drug Status: This abstract does not discuss or include any thoracolumbar spine applicable devices or drugs. Takashi Hirase, MD, MPH

4:24–4:30 p.m. 15. Diabetes is associated with greater leg pain 1The University of Tokyo Hospital, Tokyo, Japan; 2The University of Tokyo, and worse patient reported outcomes at one year Tokyo, Japan after lumbar spine surgery FDA Device/Drug Status: This abstract does not discuss or include any Kosei Nagata, MD1*; Yasushi Oshima, MD, PhD2 applicable devices or drugs.

4:30–4:45 p.m. Discussion Meeting Schedule 11 Monday, July 5 (HST)/Tuesday, July 6 (JST) *Virtual presenters denoted with a green asterisk.

4:45–4:51 p.m. 16. Marijuana use is associated with increased 1Tufts Medical Center, Boston, MA, US; 2Tufts University School of Medicine, use of prescription opioids following posterior Boston, MA, US; 3Newton-Wellesley Hospital Spine Center, Newton, MA, US lumbar spine fusion surgery FDA Device/Drug Status: This abstract does not discuss or include any Andrew S. Moon, MD1; Taryn E. LeRoy, MD1*; Vahe applicable devices or drugs. Yacoubian, BS2; Marissa Gedman, BA, MS2; Jessica P. Aidlen, MD3; Ashley L. Rogerson, MD1

4:51–4:57 p.m. 17. Risk factors for mechanical complications 1Boston Medical Center, Boston, MA, US; 2Boston University School of following the Minimally Invasive Antepsoas (ATP) Medicine, Boston, MA, US; 3Boston, MA, US; 4QAAST1, London, United lumbar and lumbosacral arthrodesis Kingdom Aziz Saade, MD1*; Tony Tannoury, MD2; Rahul A. Bhale, FDA Device/Drug Status: This abstract does not discuss or include any BA3; Qasim S. Ajmi, MBBS, FRCS4 applicable devices or drugs.

4:57–5:03 p.m. 18. Prophylactic use of local vancomycin does 1Los Angeles, CA, US; 2Pasadena, CA, US; 3Shriners for Children Medical not decrease acute surgical site infection in Center, Pasadena, CA, US adolescent idiopathic scoliosis FDA Device/Drug Status: This abstract does not discuss or include any Stephen Stephan, MD1; De-An Zhang, MD3; Marilan applicable devices or drugs. Luong, MPH2; Robert Cho, MD3; Selina Poon, MD3

5:03–5:09 p.m. 19. Frailty is a better predictor than age of 1Dept of Neurosurgery, University of Nebraska Medical Center, Omaha, NE, mortality and perioperative complications after US; 2St. Michael’s Hospital, University of Toronto, Toronto, Canada; 3Toronto surgery for Degenerative Cervical Myelopathy: Western Hospital, Toronto, ON, Canada An analysis of 41,369 patients from the NSQIP FDA Device/Drug Status: This abstract does not discuss or include any database 2010-2018 applicable devices or drugs. Jamie R. Wilson, MD, FRCS, MSc1; Jefferson Wilson, MD, PhD, FRCSC2; Michael G. Fehlings, MD, PhD, FRCSC3

5:09–5:15 p.m. 20. Increasing frailty is negatively correlated 1Dept of Neurosurgery, University of Nebraska Medical Center, Omaha, with long term functional outcomes after surgery NE, US; 2St. Michael’s Hospital, University of Toronto, Toronto, Canada; for degenerative cervical myelopathy; 757 3Rothman Institute, Philadelphia, PA, US; 4Toronto Western Hospital, patients from the CSM-NA and CSM-I multicenter Toronto, ON, Canada observational studies FDA Device/Drug Status: This abstract does not discuss or include any Jamie R. Wilson, MD, FRCS, MSc1; Jefferson Wilson, applicable devices or drugs. MD, PhD, FRCSC2; Alexander R. Vaccaro, MD, PhD3; Michael G. Fehlings, MD, PhD, FRCSC4

5:15–5:30 p.m. Discussion

5:30 p.m. HST / 12:30 p.m. JST General Meeting Adjourns Meeting Schedule 12 Tuesday, July 6 (HST)/Wednesday, July 7 (JST) *Virtual presenters denoted with a green asterisk.

11:30 a.m.-6:00 p.m. HST Registration/Speaker Information Center Grand Ballroom Foyer

11:45 a.m.-5:00 p.m. HST Technical Exhibition Grand Ballroom III

12:00-1:30 p.m. HST / 7:00-8:30 a.m. JST Symposium: Minimally Invasive Spine Surgery Grand Ballroom I & II Moderators: John C. Liu, MD University of Southern California Spine Center, Dept. of Neurosurgery Ken Ishii, MD* International University of Health and Welfare

Minimally invasive spine surgery (MIS) is very popular among 12:25-12:35 p.m. HST / 7:25-7:35 a.m. JST many surgeons and patients today. While MIS has been around Decompression and Fusion Technique with the Use of Spinal for more than 20 years, it remains a very controversial and Endoscope hotly debated topic in spine surgery. Questions remain whether Hiroshi Yamada, MD, PhD* MIS is truly better for patients and their clinical outcomes. In Wakayama Medical University this symposium, faculty will present recent advancements of MIS treatments for degenerative spine disease. 12:35-12:45 p.m. HST / 7:35-7:45 a.m. JST Lateral Access Minimally Invasive Spine Surgery: Upon completion of this symposium, participants should gain Current and Future Prospects strategies to: Ken Ishii, MD, PhD* • Determine indications for MIS in spine surgery and International University of Health and Welfare recognize the benefi ts and limitation of MIS surgery; • Consider and incorporate the advantages of endoscopy in 12:45-12:55 p.m. HST / 7:45-7:55 a.m. JST spine surgery; New Anterior Approach to L5/S1 • Adopt technological advancement to improve outcomes Seiji Ohtori, MD, PhD* Chiba University and reduce complications in MIS. 12:55-1:05 p.m. HST / 7:55-8:05 a.m. JST Agenda How to Incorporate Virtual Reality and Augmented Reality in 12:00-12:05 p.m. HST / 7:00-7:05 a.m. JST Improving MIS Learning Curve Introduction Nathaniel P. Brooks, MD John C. Liu, MD University of Wisconsin-Madison University of Southern California Spine Center, Dept. of Neurosurgery 1:05-1:15 p.m. HST / 8:05-8:15 a.m. JST 12:05-12:15 p.m. HST / 7:05-7:15 a.m. JST Navigation and Robotics for Minimally Invasive Posterior Tubular Approaches for Treatment of Lumbar Spine Surgery Degenerative Spine Disease Patrick C. Hsieh, MD, MS John C. Liu, MD University of Southern California Spine Center, Dept. of Neurosurgery University of Southern California Spine Center, Dept. of Neurosurgery 1:15-1:25 p.m. HST / 8:15-8:25 a.m. JST 12:15-12:25 p.m. HST / 7:15-7:25 a.m. JST Complication Avoidance and Management in MIS Transforaminal Full Endoscopic Lumbar Spine Surgery Paul Park, MD under Local Anesthesia: Future Perspective University of Michigan, Dept. of Neurosurgery Koichi Sairyo, MD, PhD* Tokushima University 1:25-1:30 p.m. HST / 8:25-8:30 a.m. JST Questions and Discussion Meeting Schedule 13 Tuesday, July 6 (HST)/Wednesday, July 7 (JST) *Virtual presenters denoted with a green asterisk.

1:30-2:00 p.m. HST / 8:30-9:00 a.m. JST Networking Break/Technical Exhibition Grand Ballroom III

2:00-3:00 p.m. HST / 9:00-10:00 a.m. JST Abstract Session: Cervical Spine Grand Ballroom I & II Moderator: John G. Finkenberg, MD Orthopedic Specialists of San Diego

2:00–2:06 p.m. 21. Role of high sensitive C-reactive protein as Pgimer, Chanfi garh, Chandigarh, India a prognostic marker in determining functional FDA Device/Drug Status: This abstract does not discuss or include any outcome after interlaminar epidural steroid applicable devices or drugs. injection in cervical radiculopathy Vijay G. Goni, MB, MD, PhD*

2:06–2:12 p.m. 22. Fixation stability of four different cervical disc 1The University of Tennessee Health Science Center, Memphis, TN, US; 2 3 4 prostheses endplate fi xation confi gurations Medtronic, Memphis, TN, US; Memphis, TN, US; Semmes-Murphey Clinic, Santa Clarita, CA, US; 5Semmes-Murphey Clinic, Memphis, TN, US Denis J. DiAngelo, PhD1; Daniel Hoyer, MS2; Chloe Chung, MS3; Tyler Carson, DO4; Kevin T. Foley, MD, FDA Device/Drug Status: Prodisc C (Approved for this indication), Prodisc FACS5 C Vivo (Investigational/Not approved), Prodisc C Nova (Investigational/Not approved), Prodisc C SK (Investigational/Not approved)

2:12–2:18 p.m. 23. Clinical features of extension teardrop Tokai University School of Medicine, Isehara, Kanagawa, Japan fractures of the axis: Review of 19 cases FDA Device/Drug Status: This abstract does not discuss or include any applicable devices or drugs. Masahiko Watanabe, MD, PhD*

2:18–2:24 p.m. 24. Effect of laminectomy width and sagittal 1John Peter Smith Hospital, Fort Worth, TX, US; 2JPS Health Network, Fort alignment on spinal cord drift Worth, TX, US; 3John Peter Smith, Frisco, TX, US Addison R. Wood, DO, PhD1; William Pipkin, MD2; FDA Device/Drug Status: This abstract does not discuss or include any Varun Sambhariya, MD3 applicable devices or drugs.

2:24–2:30 p.m. 25. The features of sagittal alignment among Department of Orthopedics and Orthopedic Research Institute, West China patients with occipitocervical fusion: How Hospital, Sichuan University, Chengdu, China much of a difference does the existing surgery FDA Device/Drug Status: This abstract does not discuss or include any make in their curvature? applicable devices or drugs. Ce Zhu, PhD*; Xi Yang, MD; Limin Liu, MD; Yueming Song, MD

2:30–2:36 p.m. 1Showa University Northern Yokohama Hospital, Yokohama, Japan; 21-5-8 26. Characteristics of prolonged healing in Hatanodai Shinagawa-ku, Tokyo, Japan; 3Hospital for Special Surgery, New atlantoaxial rotatory fi xation treatment York, NY, US; 4Showa University Hospital, Shinagawa-ku, Tokyo, Japan; 5Showa Yusuke Oshita, MD, PhD1*; Haruka Emori, MD, PhD1; University School of Medicine, Department of Orthopedics Surgery, Tokyo, Koji Ishikawa, MD, PhD2; Akira Matsuoka, MD4; Hiroshi Japan; 6Showa University Koto Toyosu Hospital, Tokyo, Japan; 7Showa Univesity Maruyama, PhD, MD4; Ichiro Okano, MD3; Yoshifumi Fujigaoka Hospital, Yokohama, Kanagawa, Japan; 8Showa University, Tokyo, Kudo, MD, PhD4; Toshiyuki Shirahata, MD, PhD5; Tokyo, Japan Yushi Hoshino, MD, PhD6; Koji Kanzaki, MD7; Tomoaki FDA Device/Drug Status: This abstract does not discuss or include any applicable Toyone, MD, PhD8 devices or drugs. Meeting Schedule 14 Tuesday, July 6 (HST)/Wednesday, July 7 (JST) *Virtual presenters denoted with a green asterisk.

2:36–2:42 p.m. 27. Characteristic features of cervical spine 1Showa University Hospital, Shinagawa-ku, Tokyo, Japan; 2Hospital for deformity in Dropped Head Syndrome Special Surgery, New York, NY, US; 31-5-8 Hatanodai Shinagawa-ku, Tokyo, Japan; 4Showa University, Tokyo, Japan; 5Tokyo, Shinagawa, Japan; 6Showa 1 ; Ichiro Okano, MD2; Koji Yoshifumi Kudo, MD, PhD * Univ. Northern Yokohama Hosp., Yokohama, Japan; 7Showa University Koto Ishikawa, MD, PhD3; Akira Matsuoka, MD1; Hiroshi Toyosu Hospital, Tokyo, Japan; 8Showa Univ., Shinagawa-ku, Japan Maruyama, PhD, MD4; Ryo Yamamura, PhD5; Yusuke Oshita, MD, PhD6; Yushi Hoshino, MD, PhD7; Katsunori FDA Device/Drug Status: This abstract does not discuss or include any Inagaki, MD, PhD8; Tomoaki Toyone, MD, PhD4 applicable devices or drugs.

2:42–3:00 p.m. Discussion

3:00-4:30 p.m. HST / 10:00-11:30 a.m. JST Symposium: Adult Spinal Deformity Grand Ballroom I & II Moderators: Charles A. Reitman, MD Medical University of South Carolina, Dept. of Orthopaedics Yukihiro Matsuyama, MD, PhD* Hamamatsu Medical University

With an increasingly aging as well as more active population, 3:25-3:35 p.m. HST / 10:25-10:35 a.m. JST adult spinal deformity is one of the fastest growing and Selection of Osteotomies and Spinal Releases in Treatment challenging areas of spine surgery. Faculty will discuss of Adult Spinal Deformity the evaluation principles, predictive modeling and surgical Raymond J. Hah, MD techniques to optimize clinical outcomes and reduce Keck School of Medicine, University of Southern California complications. 3:35-3:45 p.m. HST / 10:35-10:45 a.m. JST Surgery for Adult Spinal Deformity: Osteotomy and Upon completion of this symposium, participants should gain Complication, How to Prevent Complications strategies to: Yukihiro Matsuyama, MD, PhD* • Determine contemporary principles and technological Hamamatsu Medical University advances in deformity evaluation; • Appreciate the advantages and disadvantages for the 3:45-3:55 p.m. HST / 10:45-10:55 a.m. JST various deformity correction options; MIS for Treatment of Adult Spinal Deformity: Indications • Recognize complication mitigation strategies. and Limitations Paul Park, MD Agenda University of Michigan, Dept. of Neurosurgery 3:00-3:05 p.m. HST / 10:00-10:05 a.m. JST 3:55-4:05 p.m. HST / 10:55-11:05 a.m. JST Welcome and Introduction Extensive Corrective Fusion Surgery for Severe Charles A. Reitman, MD Medical University of South Carolina, Dept. of Orthopaedics Spinal Deformity in Patients with Parkinson’s Disease Yu Yamato, MD, PhD* Hamamatsu Medical University 3:05-3:15 p.m. HST / 10:05-10:15 a.m. JST Preoperative Planning for Adult Spinal Deformity Surgery: 4:05-4:15 p.m. HST / 11:05-11:15 a.m. JST How to Optimize Preparation to Improve Surgical and Indication for Pelvic Fixation and Selection of Techniques Clinical Results Norman B. Chutkan, MD Charles A. Reitman, MD The CORE Institute Medical University of South Carolina, Dept. of Orthopaedics 4:15-4:25 p.m. HST / 10:15-10:25 a.m. JST 3:15-3:25 p.m. HST / 10:15-10:25 a.m. JST How to Reduce Implant-Related Complication Rates, Need of Universal Patient Proﬁ ling System for Decision Pseudo, and Revision Surgery in Adult Spinal Deformity Making of Adult Spine Deformity Treatment Surgery Manabu Ito, MD, PhD* Mitsuru Yagi, MD, PhD* National Hospital Org. Hokkaido Medical Center Keio University

4:25-4:30 p.m. HST / 10:25-10:30 a.m. JST Questions and Discussion Meeting Schedule 15 Tuesday, July 6 (HST)/Wednesday, July 7 (JST) *Virtual presenters denoted with a green asterisk.

4:30-5:00 p.m. HST / 11:30 a.m.-12:00 p.m. JST Networking Break/Technical Exhibition Grand Ballroom III

5:00-6:00 p.m. HST / 12:00-1:00 p.m. JST Virtual Abstract Session:* * All presenters in this session are now virtual. The moderator will still be New Concepts in Imaging available in person during the live session to take questions from the in person and virtual audiences. Grand Ballroom I & II Moderator: Scott Kreiner, MD Barrow Brain and Spine

5:00–5:06 p.m. 28. Extensive subphenotyping of lumbar modic 1Spine Care Center, Wakayama Medical University Kihoku Hospital, Ito-gun, changes and their association with low back Wakayama, Japan; 2Wakayama, Japan; 3Wakayama Medical University, pain in a large population-based cohort: The Wakayama, Wakayama, Japan; 4Tokyo, Japan; 5Queen Mary Hospital, Hong Wakayama Spine Study Kong, Hong Kong; 6Wakayama Medical University, Dept of Orthopaedic Surgery, Masatoshi Teraguchi, MD, PhD1*; Hiroshi Hashizume, Wakayama, Japan MD, PhD2; Hidenobu Tamai, MD3; Hiroyuki Oka, MD4; FDA Device/Drug Status: This abstract does not discuss or include any Dino Samartzis, ScD, PhD, MSc5; Noriko Yoshimura, applicable devices or drugs. MD, PhD4; Hiroshi Yamada, MD, PhD6

5:06–5:12 p.m. 1 29. Facet joint opening on CT is a predictor Osaka City University Graduate School of Medicine, Osaka City, Japan; 2Osaka for poor clinical outcomes after less invasive City University, Osaka, Japan; 3Dept. of Orthopaedic Surgery, Osaka City decompression surgery for lumbar spinal stenosis University, Graduate School of Medicine, Osaka, Japan Kentaro Yamada, MD1*; Hiromitsu Toyoda, MD, PhD2; FDA Device/Drug Status: This abstract does not discuss or include any Koji Tamai, MD2; Shinji Takahashi, MD2; Akinobu Suzuki, applicable devices or drugs. MD, PhD2; Masatoshi Hoshino, MD3; Hidetomi Terai, MD, PhD3; Hiroaki Nakamura, MD, PhD1

5:12–5:18 p.m. 30. Machine vision image guided system in spinal 1Stanford, CA, US; 2Stanford University School of Medicine, Department fusion surgery: Early clinical experience of Neurosurgery, Stanford, CA, US; 3Stanford University, Palo Alto, CA, US; 4Stanford School of Medicine, Stanford, CA, US; 5Stanford University Harsh Wadhwa, BS1 ; Christopher Leung, BA2; Matthew * School of Medicine / Hospital & Clinics, Palo Alto, CA, US; 6Stanford Dept of Sklar, BS3; Karen Malacon, BA4; Elizabeth Tong, MD1; Neurosurgery, Stanford, CA, US John Ratliff, MD5; Corinna Zygourakis, MD6 FDA Device/Drug Status: 7D Surgical System (Approved for this indication)

5:18–5:24 p.m. 31. Novel magnetic resonance imaging Keio University School of Medicine, Department of Orthopaedic Surgery, techniques for assessing intervertebral disc Tokyo, Japan degeneration and regeneration FDA Device/Drug Status: This abstract does not discuss or include any Daisuke Nakashima, MD, PhD* applicable devices or drugs.

5:24–5:30 p.m. 32. An analysis for safety insertion of sacral 1Osaka City University Graduate School of Medicine, Osaka City, Japan; 2Eniwa alar iliac screw on the fluoroscopy, using Hospital, Eniwa, Japan three-dimensional analyzing software FDA Device/Drug Status: This abstract does not discuss or include any Kentaro Yamada, MD1*; Yuichiro Abe, MD, PhD2; applicable devices or drugs. Hiroaki Nakamura, MD, PhD1 Meeting Schedule 16 Tuesday, July 6 (HST)/Wednesday, July 7 (JST) *Virtual presenters denoted with a green asterisk.

5:30–5:36 p.m. 33. Kinematics of the spine and hips following University of California San Francisco, San Francisco, CA, US thoracolumbar fusion correlated to HRQOL scores FDA Device/Drug Status: This abstract does not discuss or include any Luana Leal, BS; Shane Burch, MD* applicable devices or drugs.

5:36–5:42 p.m. 34. Prevalence of modic changes in pediatric 1Tokushima University, Tokushima, Japan; 2Kuramoto, Japan; 3Tokushima, patients with low back pain Japan; 4Tokushima Prefecture Naruto Hospital, Department of Orthopedic Surgery, Naruto, Tokushima, Japan Hiroaki Manabe, MD1*; Toshinori Sakai, MD, PhD1; Masatoshi Morimoto, MD2; Fumitake Tezuka, MD, FDA Device/Drug Status: This abstract does not discuss or include any PhD1; Kazuta Yamashita, MD3; Takashi Chikawa, MD, applicable devices or drugs. PhD4; Koichi Sairyo, MD, PhD1

5:42–6:00 p.m. Discussion

6:00 p.m. HST / 1:00 p.m. JST General Meeting Adjourns

6:00-7:30 p.m. HST TICKETED EVENT Fireside Chat at the Beach Osteobiologics: How Do You Choose Biologics in Your Practice and What Works for You? Moderator: Patrick C. Hsieh, MD, MS University of Southern California Spine Center, Dept. of Neurosurgery

Faculty: Jeffrey C. Wang, MD University of Southern California Spine Center Zorica Buser, PhD Keck School of Medicine, University of Southern California Meeting Schedule 17 Wednesday, July 7 (HST)/Thursday, July 8 (JST) *Virtual presenters denoted with a green asterisk.

11:30 a.m.-6:00 p.m. HST Registration/Speaker Information Center Grand Ballroom Foyer

11:45 a.m.-5:00 p.m. HST Technical Exhibition Grand Ballroom III

11:55 a.m.-12:00 p.m. HST / 6:55-7:00 a.m. JST Opening Remarks Grand Ballroom I & II Charles A. Reitman, MD Medical University of South Carolina, Dept. of Orthopaedics Masaya Nakamura, MD, PhD* Keio University

12:00-1:30 p.m. HST / 7:00-8:30 a.m. JST Symposium: Management of Spine Trauma and Spinal Cord Injury Grand Ballroom I & II Moderators: Norman B. Chutkan, MD The CORE Institute Masaya Nakamura, MD, PhD* Keio University

Faculty will discuss options for management of spinal trauma, 12:25-12:35 p.m. HST / 7:25-7:35 a.m. JST including understanding the stability and biomechanics of What’s the Role and Indication for Posterior Indirect injury and advances in technology, both for assessment as well Decompression for Thoracolumbar Fractures? as treatment. John G. Finkenberg, MD Orthopedic Specialists of San Diego Upon completion of this symposium, participants should gain 12:35-12:45 p.m. / 7:35-7:45 a.m. JST strategies to: Indication and Considerations for Anterior Approach in • Determine contemporary principles of stability and surgical Treatment of Thoracolumbar Fractures indications; Norman B. Chutkan, MD • Compare and contrast advantages of anterior vs. posterior The CORE Institute approach for unstable thoracolumbar fractures; • Recognize the role of biologics in spinal cord injury. 12:45-12:55 p.m. / 7:45-7:55 a.m. JST Percutaneous Fixation without Fusion in Treatment of Agenda Thoracolumbar Fractures Paul Park, MD 12:00-12:05 p.m. / 7:00-7:05 a.m. JST University of Michigan, Dept. of Neurosurgery Welcome and Introduction Norman B. Chutkan, MD 12:55-1:05 p.m. / 7:55-8:05 a.m. JST The CORE Institute Minimally Invasive/Mini-open Vertebrectomy and Anterior Decompression/Fusion for Thoracolumbar Fractures 12:05-12:15 p.m. / 7:05-7:15 a.m. JST Nathaniel P. Brooks, MD Upper Cervical Spine Injury: Clinical Feature and Treatment University of Wisconsin-Madison Strategy 1:05-1:15 p.m. / 8:05-8:15 a.m. JST Masahiko Watanabe, MD, PhD * Surgical Treatment for Neurological Deﬁ cits and Severe Tokai University Back Pain Following Osteoporotic Vertebral Fracture 12:15-12:25 p.m. / 7:15-7:25 a.m. JST Shinji Takahashi, MD* Updates on Classiﬁ cation and Indication for Treatments of Osaka City University Thoracolumbar Fractures 1:15-1:25 p.m. / 8:15-8:25 a.m. JST Charles A. Reitman, MD Regenerative Medicine for Spinal Cord Injury using iPSC Medical University of South Carolina, Dept. of Orthopaedics Masaya Nakamura, MD, PhD* Keio University 1:25-1:30 p.m. / 8:25-8:30 a.m. JST Questions and Discussion Meeting Schedule 18 Wednesday, July 7 (HST)/Thursday, July 8 (JST) *Virtual presenters denoted with a green asterisk.

1:30-2:00 p.m. HST / 8:30-9:00 a.m. JST Networking Break/Technical Exhibition Grand Ballroom III

2:00-3:00 p.m. HST / 9:00-10:00 a.m. JST Abstract Session: Use of New Technology in Spine Care Grand Ballroom I & II Moderator: Jean-Jacques Abitbol, MD California Spine Group

2:00–2:06 p.m. 35. Telemedicine visits generate accurate 1Boston, MA, US; 2Harvard Combined Orthopaedic Residency Program, Boston, interventional procedure plans in spine patients MA, US; 3Brigham and Women’s Hospital, Boston, MA, US; 4Brigham and without in person evaluations Women’s Hospital, Dept. of Orthopedic Surgery, Boston, MA, US Harry M. Lightsey IV, MD1; Alexander Crawford, MD2; FDA Device/Drug Status: This abstract does not discuss or include any Grace Xiong, MD1; Brendan Striano, MD2; Andrew J. applicable devices or drugs. Schoenfeld, MD3; Andrew Simpson, MD4

2:06–2:12 p.m. 36. Successful fusion in cervical and lumbar 1Cedars-Sinai Medical Center, Los Angeles, CA, US; 2Texas Spine Care Center, spinal surgery using unique bioactive glass putty San Antonio, TX, US; 3SpineCare Medical Group, Daly City, CA, US; 4Spine 5 George Hanna, MD1; Adam Bruggeman, MD2; Paul J. Institute of South Florida, Delray Beach, FL, US; Spine Institute, Los Angeles, Slosar, MD3; Edward H. Chung, MD4; Hyun W. Bae, MD5 CA, US FDA Device/Drug Status: This abstract does not discuss or include any applicable devices or drugs.

2:12–2:18 p.m. 37. A novel comprehensive model to describe 1University of New Mexico Health Sciences, Albuquerque, NM, US; 2Madison, vertebral body motion following interbody fusion WI, US; 3UW Health, Madison, WI, US; 4University of Wisconsin Spine Medicine 5 Paul J. Johnson, MD, MS1; 2; Clinic, Madison, WI, US; Univ of Wisc Orthopedics & Rehabilitation, Madison, James T. Bernatz, MD 6 Brian McGowan, MD3; Miranda Bice, MD4; Paul A. WI, US; University of Wisconsin, Madison, WI, US Anderson, MD5; Seth K. Williams, MD6 FDA Device/Drug Status: This abstract does not discuss or include any applicable devices or drugs.

2:18–2:24 p.m. 38. Examination of a new external anal sphincter Fukuoka Mirai Hospital, Fukuoka, Japan recording method for preventing intraoperative FDA Device/Drug Status: This abstract does not discuss or include any bladder rectal disorder applicable devices or drugs. Yoshikazu Yanagisawa, MD, PhD

2:24–2:30 p.m. 39. Development of an optimized machine 1Los Angeles, CA, US; 2David Geffen School of Medicine at UCLA, Los learning algorithm for prediction of complications Angeles, CA, US; 3Santa Monica, CA, US; 4UCLA, Santa Monica, CA, US; 5UCLA and readmission after lumbar spinal fusion Department of Orthopaedic Surgery, Los Angeles, CA, US Akash A. Shah, MD1*; Sai Devana, MD1; Changhee Lee, FDA Device/Drug Status: This abstract does not discuss or include any MS1; Alexander Upfi ll-Brown, MD, MSc2; Elizabeth L. applicable devices or drugs. Lord, MD3; Don Y. Park, MD4; Nelson SooHoo, MD5 Meeting Schedule 19 Wednesday, July 7 (HST)/Thursday, July 8 (JST) *Virtual presenters denoted with a green asterisk.

2:30–2:36 p.m. 40. Minimum clinical important differences 1Source Healthcare, Santa Monica, CA, US; 2Clinical Radiology of Oklahoma, in outcomes at 1 year in the treatment of Edmond, OK, US; 3Vivex Biologics, Inc., Miami, FL, US; 4Wilderness Spine degenerated intervertebral discs using a viable Services, Columbus, GA, US disc tissue cellular allograft FDA Device/Drug Status: This abstract does not discuss or include any Timothy T. Davis, MD1; Douglas P. Beall, MD2; H applicable devices or drugs. Thomas Temple, MD3; J. Kenneth Burkus, MD4

2:36–2:42 p.m. 41. Patient mobilization with activity trackers 1San Francisco, CA, US; 2Jackson - PM&R, Miami, FL, US; 3California following lumbar fusion and decompression Northstate University, Elk Grove, CA, US; 4UCSF Dept of Orthopaedic Surgery, San Francisco, CA, US Hao-Hua Wu, MD1*; Andrew Logan, MD2; Steven Wright, BS3; Lionel N. Metz, MD4 FDA Device/Drug Status: This abstract does not discuss or include any applicable devices or drugs.

2:42–3:00 p.m. Discussion

3:00-4:30 p.m. HST / 10:00-11:30 a.m. JST Symposium: Novel Technology and Biologics Grand Ballroom I & II Moderators: Jean-Jacques Abitbol, MD California Spine Group Hirotaka Haro, MD, PhD* University of Yamanashi

Advances in biology, molecular and clinic research are 3:25-3:35 p.m. HST / 10:25-10:35 a.m. JST critical for advancement of spine surgery in the future. In this Clinical Outcomes of One and Two Level Cervical symposium, faculty will address novel biological research with Arthroplasty for Cervical Degenerative Disease translational implications along with clinical studies involving Jean-Jacques Abitbol, MD novel spine diagnostics and treatments. California Spine Group 3:35-3:45 p.m. HST / 10:35-10:45 a.m. JST Upon completion of this symposium, participants should gain Novel Magnetic Resonance Imaging Techniques for strategies to: Assessing Intervertebral Disc Degeneration and Regeneration • Evaluate various biologics and options to optimize bone Daisuke Nakashima, MD, PhD* union in spine fusion surgery; Keio University • Incorporate novel medical interventions and cell-based treatments for lumbar degenerative disc diseases that are 3:45-3:55 p.m. HST / 10:45-10:55 a.m. JST in development. Basivertebral Nerve Ablation for Treatment of Low Back Pain: Indication and Early Clinical Results Agenda David R. O’Brien Jr., MD 3:00-3:05 p.m. HST / 10:00-10:05 a.m. JST Medical University of South Carolina, Dept. of Orthopaedics & Physical Welcome and Introduction Medicine Jean-Jacques Abitbol, MD 3:55-4:10 p.m. HST / 10:55-11:10 a.m. JST California Spine Group Spinal Osteobiologics for Fusions from A-Z: 3:05-3:15 p.m. / 10:05-10:15 a.m. JST What’s Available and Effective? How to Make the Best The Role of Weekly Teriparatide for Bone Union during Six Choice to Optimize Fusion? Months after Single or Multi-Level Lumbar Interbody Fusion Zorica Buser, PhD for Osteoporotic Patients Keck School of Medicine, University of Southern California Hirotaka Haro, MD, PhD University of Yamanashi 4:10-4:30 p.m. HST / 11:10-11:30 a.m. JST Questions and Discussion 3:15-3:25 p.m. HST / 10:15-10:25 a.m. JST Clinical Development of Tie2 Positive Nucleus Pulposus Progenitor Cell Product for Low Back Pain Daisuke Sakai, MD, PhD* Tokai University Meeting Schedule 20 Wednesday, July 7 (HST)/Thursday, July 8 (JST) *Virtual presenters denoted with a green asterisk.

4:30-5:00 p.m. HST / 11:30 a.m.-12:00 p.m. JST Networking Break Grand Ballroom III

5:00-6:00 p.m. HST / 12:00-1:00 p.m. JST Virtual Abstract Session:* * All presenters in this session are now virtual. The moderator will still be Deformity available in person during the live session to take questions from the in person and virtual audiences. Grand Ballroom I & II Moderator: Raymond J. Hah, MD Keck School of Medicine, University of Southern California

5:00–5:06 p.m. 42. Use of topical tranexemic acid reduces 1Broward Health Medical Center, Ft Lauderdale, FL, US; 2Nicklaus Children’s effective blood loss and transfusion requirements Hospital, Miami, FL, US; 3Center for Spinal Disorders, Orthopedic Surgery, in spinal deformity correction in patients with Nicklaus Children’s Hospital, Miami, FL, US; 4Winnipeg Spine Program, adolescent idiopathic scoliosis Winnipeg, Canada; 5Miami, FL, US Blaze Emerson, DO1*; Subaraman Ramchandran, MD2; FDA Device/Drug Status: tranexemic acid (Approved for this indication) Stephen G. George Jr, MD2; Thomas J. Errico, MD3; Ali Mansour, MD4; Alexander Mihas, BS5

5:06–5:12 p.m. 43. The correlation analysis of pelvic incidence 1Bordeaux, France; 2Polyclinique Bordeaux Nord Aquitaine, Bordeaux, France; minus lumbar lordosis with pelvic incidence from 3New York-Presbyterian The Allen Hospital, New York, NY, US; 4Columbia a database of 488 asymptomatic volunteers University Medical Center, New York, NY, US; 5Niigata Spine Surgery Center, Niigata City, Japan; 6National University Health System, Singapore, Singapore; Jean-Charles Le Huec, MD, PhD1 ; Stéphane Bourret, * 7Saint Louis, MO, US; 8Department of Orthopedic Surgery, Keio University School PhD2; Zeeshan Sardar, MD, MSc3; Meghan Cerpa, of Medicine, Tokyo, Japan MPH4; Kazuhiro Hasegawa, MD, PhD5; Hwee Weng Dennis Hey, MBBS, FRCS6; Michael P. Kelly, MD7; FDA Device/Drug Status: This abstract does not discuss or include any Lawrence G. Lenke, MD8 applicable devices or drugs.

5:12–5:18 p.m. 44. How to reduce implant-related complication School of Medicine, Tokyo, Japan; 2Keio University, Tokyo, Japan; 3Saiseikai rates, pseudo, and revision surgery in adult spinal Central Hospital, Tokyo, Japan; 4Saitama, Japan; 5Toronto Western Hospital, deformity surgery Toronto, ON, Canada Mitsuru Yagi, MD, PhD1*; Satoshi Suzuki, MD2; Ejiiro FDA Device/Drug Status: This abstract does not discuss or include any Okada, MD3; Satoshi Nori, MD, PhD1; Osahiko Tsuji, MD, applicable devices or drugs. PhD4; Narihito Nagoshi, MD, PhD5; Masaya Nakamura, MD, PhD1; Morio Matsumoto, MD2; Kota Watanabe, MD2 1Department of Orthopedic Surgery, Keio University

5:18–5:24 p.m. 1San Francisco, CA, US; 2Milpitas, CA, US; 3Oakland, CA, US; 4University of 45. Perioperative outcomes of anterior vertebral California, San Francisco Department of Orthopaedic Surgery, San Francisco, spinal tethering versus posterior spinal fusion CA, US; 5University of California - San Francisco (UCSF), San Francisco, CA, US for skeletally immature patients with idiopathic scoliosis FDA Device/Drug Status: This abstract does not discuss or include any applicable devices or drugs. Hao-Hua Wu, MD1*; Satvir Saggi, BS2; Toshali Katyal, BA3; Sachin Allahabadi, MD4; Jeremy Siu, BS1; Mohammad Diab, MD5 Meeting Schedule 21 Wednesday, July 7 (HST)/Thursday, July 8 (JST) *Virtual presenters denoted with a green asterisk.

5:24–5:30 p.m. 46. The impact of preoperative cross-sectional 1Hospital for Special Surgery, New York, NY, US; 2New York, NY, US; 3Taipei area of psoas muscle on postoperative outcomes Veterans General Hospital, Taipei, Taiwan of adult spinal deformity surgery FDA Device/Drug Status: This abstract does not discuss or include any Hikari Urakawa1*; Kosuke Sato, MD2; Jonathan applicable devices or drugs. Elysee1; Renaud Lafage, MSc1; Avani S. Vaishnav, MBBS1; Yu-Cheng Yao, MD3; Han Jo Kim, MD1; Frank J. Schwab, MD1; Virginie Lafage, PhD1; Catherine Himo Gang, MPH1; Sheeraz A. Qureshi, MD, MBA1

5:30–5:36 p.m. 47. Moved to Adult Spinal Deformity

5:36–5:42 p.m. 48. Spinopelvic sagittal alignment as predictor of adjacent segment disease after transforaminal lumbar interbody fusion Ghanshyam Kakadiya, MS, MBBS* Department of Spine Surgery, Mohali, Panjab, India FDA Device/Drug Status: This abstract does not discuss or include any applicable devices or drugs.

5:42–6:00 p.m. Discussion

6:00 p.m. HST / 1:00 p.m. JST General Meeting Adjourns

6:00-7:30 p.m. HST TICKETED EVENT Fireside Chat at the Beach How Do You Evaluate and Adopt Novel Technologies in Spine Surgery to Improve Outcomes and Minimize Complications? Moderator: Charles A. Reitman, MD Medical University of South Carolina, Dept. of Orthopaedics

Faculty: Raymond J. Hah, MD Keck School of Medicine, University of Southern California Paul Park, MD University of Michigan, Dept. of Neurosurgery Meeting Schedule 22 Thursday, July 8 (HST)/Friday, July 9 (JST) *Virtual presenters denoted with a green asterisk.

11:30 a.m.-4:30 p.m. HST Registration/Speaker Information Center Grand Ballroom Foyer

11:55 a.m.-12:00 p.m. HST / 6:55-7:00 a.m. JST Opening Remarks Grand Ballroom I & II Charles A. Reitman, MD Medical University of South Carolina, Dept. of Orthopeadics Masaya Nakamura, MD, PhD* Keio University

12:00-1:30 p.m. / 7:00-8:30 a.m. JST Virtual Abstract Session:* * All presenters in this session are now virtual. The moderator will still be Thoracolumbar Surgery available in person during the live session to take questions from the in Grand Ballroom I & II person and virtual audiences. Moderator: Charles A. Reitman, MD Medical University of South Carolina, Dept. of Orthopaedics

12:00–12:06 p.m. 49. Microendoscopic decompression for Wakayama Medical University, Dept of Orthopaedic Surgery, Wakayama, lumbosacral foraminal stenosis: A novel surgical Japan strategy based on anatomical considerations FDA Device/Drug Status: This abstract does not discuss or include any using 3D image fusion with MRI/CT applicable devices or drugs. Hiroshi Yamada, MD, PhD*

12:06–12:12 p.m. 50. Clinical comparison of biportal endoscopic 1Seirei Hamamatsu General Hospital, Hamamatsu, Japan, Shizuoka, Japan; spine surgery versus microscopic spine surgery 2Hamamatsu, Japan for lumber disc herniation FDA Device/Drug Status: This abstract does not discuss or include any Takaki Yoshimizu, MD1*; Kanji Sasaki, MD, PhD2 applicable devices or drugs.

12:12–12:18 p.m. 51. Surgical treatment of primary mobile spine 1Mayo Clinic, Rochester, MN, US; 2Rochester, MN, US; 3Mayo Clinic Dept of chordoma Orthopedic Surgery - Gonda 14, Rochester, MN, US Joshua Kolz, MD, MS1*; Matthew Houdek, MD1; FDA Device/Drug Status: This abstract does not discuss or include any Michael J. Yaszemski, MD, PhD2; Peter Rose, MD3; applicable devices or drugs. Elizabeth Wellings, MD, MEng1; Michelle J. Clarke, MD1

12:18–12:24 p.m. 52. Five-year revision rates for elective multi- 1UCSF, San Francisco, CA, US; 2UCSF Spine Center, San Francisco, CA, US level lumbar instrumented fusions in the elderly: FDA Device/Drug Status: This abstract does not discuss or include any An analysis of state databases applicable devices or drugs. Daniel D. Cummins1*; Alexander A. Theologis, MD2

12:24–12:30 p.m. 1 2 53. Physical therapy on postoperative day 0 Columbia, MO, US; University of Missouri School of Medicine, Columbia, MO, US; 3Missouri Orthopaedic Institute, Columbia, MO, US; 4University of Missouri following lumbar spine surgery decreases length Health Care, Columbia, MO, US; 5Missouri Spine Center, Columbia, MO, US; of stay 6University of Missouri, Columbia, MO, US Blaine Manning, MD1 ; Nathan Cherian2; Ahdarsh * FDA Device/Drug Status: This abstract does not discuss or include any Vallabhaneni1; Stefan Hanish, BS2; Andrew Lee1; applicable devices or drugs. Suryanshi Rawat, BS3; Casey A. Fogarty3; Mark Lambrechts, MD3; Fassil B. Mesfi n, MD, PhD4; Muhammad Z. Mirza, MD3; Theodore J. Choma, MD5; Don K. Moore, MD6 Meeting Schedule 23 Thursday, July 8 (HST)/Friday, July 9 (JST) *Virtual presenters denoted with a green asterisk.

12:30–12:45 p.m. Discussion

12:45–12:51 p.m. 54. Surgical intervention is associated with 1Boston, MA, US; 2Harvard Combined Orthopaedic Residency Program, improvements in ASIA impairment scale in Boston, MA, US; 3Massachusetts General Hospital, Boston, MA, US thoracic and lumbar gunshot induced spinal cord FDA Device/Drug Status: This abstract does not discuss or include any injuries applicable devices or drugs. Brian C. Goh, MD, PhD1*; Brendan Striano, MD2; Alexander Crawford, MD2; Daniel G. Tobert, MD3; Harold A. Fogel, MD1; Thomas D. Cha, MD, MBA3; Joseph H. Schwab, MD3; Christopher M. Bono, MD3; Stuart H. Hershman, MD3

12:51–12:57 p.m. 55. Clinical outcomes of minimally invasive 1Yodogawa Christian Hospital, Osaka City, Japan; 2Osaka City University, posterior decompression for lumbar spinal Osaka, Japan; 3Dept. of Orthopaedic Surgery, Osaka City University, Graduate stenosis with degenerative spondylolisthesis School of Medicine, Osaka, Japan; 4Osaka City University Graduate School of Medicine, Osaka, Japan Yuto Kobayashi, MD1*; Koji Tamai, MD2; Hiromitsu Toyoda, MD, PhD2; Hidetomi Terai, MD, PhD3; Masatoshi FDA Device/Drug Status: This abstract does not discuss or include any Hoshino, MD3; Akinobu Suzuki, MD, PhD2; Shinji applicable devices or drugs. Takahashi, MD2; Yusuke Hori, MD4; Hiroaki Nakamura, MD, PhD4

12:57–1:03 p.m. 56. Clinical effectiveness of comprehensive 1Sapporo, Japan; 2National Hospital Organization Hokkaido Medical Center, medicine in treatment of pyogenic spondylitis in Sapporo, Japan; 3Tan Tock Seng Hospital, Singapore, Singapore the elderly FDA Device/Drug Status: This abstract does not discuss or include any Hidekazu Yoshizaki, NP1; Manabu Ito, MD, PhD2*; applicable devices or drugs. Tzong-Jing Victor Wang, FRCS, MBBS3

1:03–1:09 p.m. Hospital of University of Pennsylvania, Philadelphia, PA, US 57. Duration of overlap during posterior only FDA Device/Drug Status: This abstract does not discuss or include any lumbar fusion does not predict patient outcomes applicable devices or drugs. Ali Farooqi, BA*; Neil Malhotra, MD

1:09–1:15 p.m. 58. Comparison of outcomes of primary 1Hospital for Special Surgery, New York, NY, US; 2New York, US; 3Hospital for and revision minimally invasive lumbar Special Surgery, Stamford, CT, US microdiscectomy FDA Device/Drug Status: This abstract does not discuss or include any Avani S. Vaishnav, MBBS1 ; Hikari Urakawa1; Jung * applicable devices or drugs. Mok, BS2; Evan Sheha, MD3; Steven J. McAnany, MD3; Catherine Himo Gang, MPH1; Sheeraz A. Qureshi, MD, MBA1

1:15–1:30 p.m. Discussion

1:30-2:00 p.m. / 8:30-9:00 a.m. JST Networking Break Grand Ballroom III Meeting Schedule 24 Thursday, July 8 (HST)/Friday, July 9 (JST) *Virtual presenters denoted with a green asterisk.

2:00-3:00 p.m. / 9:00-10:00 a.m. JST Abstract Session: Bone Health Considerations in Management of Spinal Disorders Grand Ballroom I & II Moderator: Zorica Buser, PhD Keck School of Medicine, University of Southern California

2:00–2:06 p.m. 59. Effect of cage position and insertion angle Seoul, Republic of Korea in the oblique lumbar interbody fusion: A fi nite FDA Device/Drug Status: This abstract does not discuss or include any element study applicable devices or drugs. Jung-Woo Hur, PhD*

2:06–2:12 p.m. 60. Variation of bone mineral density in the 1Hospital for Special Surgery, New York, NY, US; 2Seattle, WA, US; 3Indiana lumbar spine Spine Group, Carmel, IN, US Avani S. Vaishnav, MBBS1*; Philip Louie, MD2; Chirag FDA Device/Drug Status: This abstract does not discuss or include any Chaudhary, MS, MBBS1; Michael H. McCarthy, MD, applicable devices or drugs. MPH3; Ryan Lee, MBA1; Yoshihiro Katsuura, MD1; Catherine Himo Gang, MPH1; Sheeraz A. Qureshi, MD, MBA1

2:12–2:18 p.m. 61. Effect of postmenopausal state on distribution 1Hospital for Special Surgery, New York, NY, US; 2Seattle, WA, US; 3Indiana of bone mineral density in the lumbar spine Spine Group, Carmel, IN, US Avani S. Vaishnav, MBBS1*; Philip Louie, MD2; Chirag FDA Device/Drug Status: This abstract does not discuss or include any Chaudhary, MS, MBBS1; Michael H. McCarthy, MD, applicable devices or drugs. MPH3; Ryan Lee, MBA1; Yoshihiro Katsuura, MD1; Catherine Himo Gang, MPH1; Sheeraz A. Qureshi, MD, MBA1

2:18–2:24 p.m. 62. Irrigation with saline solution before the Medical University, Plovdiv-Bulgaria, Plovdiv, Bulgaria application of VTP bone cement in cases of FDA Device/Drug Status: This abstract does not discuss or include any balloon kyphoplasty applicable devices or drugs. Vladimir P. Stavrev, MD, PhD, MSc

2:24–2:30 p.m. 1 2 63. Does preoperative bone mineral density SUNY Downstate, Brooklyn, NY, US; Mayo Clinic, Rochester, MN, US; 3 impact fusion success in anterior cervical spine Mayo Clinic/Dept of Orthopedic Surgery, Rochester, MN, US surgery? A prospective cohort study FDA Device/Drug Status: This abstract does not discuss or include any Jad Bou Monsef, MD1; Zachariah Pinter, MD2; Arjun S. applicable devices or drugs. Sebastian, MD, MSc2; Brett A. Freedman, MD2; Bradford L. Currier, MD2; Benjamin D. Elder, MD, PhD2; Ahmad N. Nassr, MD3

2:30–2:36 p.m. 64. Cost benefi t analysis of routine bone biopsy E. Wolfson Medical Center, Holon, Israel during osteoporotic vertebral compression fractures FDA Device/Drug Status: This abstract does not discuss or include any augmentation procedures applicable devices or drugs. Raphael Lotan, MD Meeting Schedule 25 Thursday, July 8 (HST)/Friday, July 9 (JST) *Virtual presenters denoted with a green asterisk.

2:36–2:42 p.m. 65. Bone health optimization improves 1Madison, WI, US; 2University of Wisconsin Hospitals and Clinics, Madison, WI, osteoporosis screening and treatment prior to US; 3Mayo Clinic, Rochester, MN, US; 4University of Wisconsin, Madison, WI, 5 thoracolumbar fusion US; University of Wisconsin Orthopedics & Rehabilitation, Madison, WI, US James T. Bernatz, MD1; Alec Winzenried, MD2; Anthony FDA Device/Drug Status: This abstract does not discuss or include any L. Mikula, MD3; Seth K. Williams, MD4; Neil Binkley, MD4; applicable devices or drugs. Paul A. Anderson, MD5

2:42–3:00 p.m. Discussion

3:00-4:30 p.m. / 10:00-11:30 a.m. JST Symposium: Controversies and Debates in Management of Lumbar Degenerative Spondylolisthesis Grand Ballroom I & II Moderator: Zoher Ghogawala, MD, FACS Lahey Hospital and Medical Center, Dept. of Neurosurgery

3:05-3:20 p.m. HST / 10:05-10:20 a.m. JST Lumbar degenerative spondylolisthesis is one of most Diagnosis and Imaging of Degenerative Lumbar common diagnosis leading to chronic back pain, radiculopathy Spondylolisthesis: Tailoring Treatment Based on or neurogenic claudication in elderly patients worldwide. Subtypes and Characteristics of Lumbar Degenerative Treatment of lumbar degenerative spondylolisthesis is a hotly Spondylolisthesis controversial and debated topic despite many clinical studies Zoher Ghogawala, MD, FACS that examined the issue. Is it better to fuse or not to fuse? Lahey Hospital and Medical Center, Dept. of Neurosurgery What is the ideal approach for fusion? Can MIS and endoscopy minimize the need for fusion? International faculty will discuss 3:20-3:35 p.m. HST / 10:20-10:35 a.m. JST and debate the critical questions surrounding the treatment of Posterior Decompression and Fusion: Advantages and lumbar degenerative spondylolisthesis that are unanswered. Disadvantages of TLIF vs. Posterolateral Fusion Norman B. Chutkan, MD Upon completion of this symposium, participants should gain The CORE Institute strategies to: • Recognize and evaluate the different clinical and 3:35-3:50 p.m. / 10:35-10:50 a.m. JST radiographical presentations of lumbar degenerative Tubular Decompression without or with Fusion spondylolisthesis that can impart treatment decision and Gregory J. Przybylski, MD outcome; New Jersey Neuroscience Institute • Evaluate and adopt various surgical approaches for treatment of lumbar degenerative spondylolisthesis; 3:50-4:05 p.m. HST / 10:50-11:05 a.m. JST • Compare and consider open vs. MIS approaches for Anterior and Lateral Approaches for Treatment of Lumbar treatment of lumbar degenerative spondylolisthesis; Spondylolisthesis • Consider and recognize the impact of sagittal alignment Edward J. Dohring, MD, Spine Institute of Arizona alterations in various surgical approaches for of lumbar degenerative spondylolisthesis. 4:05-4:20 p.m. HST / 11:05-11:20 a.m. JST Open Decompression for Lumbar Degenerative Spondylolisthesis—Pros and Cons Agenda Hiroshi Ozawa, MD* 3:00-3:05 p.m. HST / 10:00-10:05 a.m. JST Introduction and Case Presentation 4:20-4:30 p.m. HST / 11:20-11:30 a.m. JST Zoher Ghogawala, MD, FACS Rebuttals and Discussion Lahey Hospital and Medical Center, Dept. of Neurosurgery

4:30 p.m. HST / 11:30 a.m. JST General Meeting Adjourns Proceedings 26

Monday, July 5 CONCLUSIONS: Cervical laminoplasty is a safe surgical procedure. Favorable long-term outcome is expected after cervical 12:00– 1:30 p.m. laminoplasty in patients with cervical myelopathy by CS and OPLL. Outcomes Following Cervical Spine Surgery However, spine surgeons must be aware that some of the patients had deteriorated during follow-up. The main cause of neurological deterioration was additional spine surgery, especially due to OPLL 1. More than 20 years follow up after cervical progression. A long postoperative follow-up should be carried out laminoplasty after laminoplasty. Yoshiharu Kawaguchi, MD, PhD FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. Toyama University, Department of Orthopaedic Surgery, Toyama, Japan BACKGROUND CONTEXT: In the early 1970s, cervical 2. Postoperative SVA >4 cm has no impact on neck laminoplasty was developed in Japan to resolve postoperative pain scores after C2-T2 fusion for myelopathy: problems after conventional laminectomy. The previous studies Results from a multicenter cohort study demonstrated that long term surgical outcomes, more than 10 years, were satisfactory after laminoplasty. As cervical laminoplasty Harold I. Salmons, MD1; Zachariah Pinter, MD1; Joshua Kolz, yields favorable outcomes, it has become the standard technique MD, MS1; Ahmad N. Nassr, MD2; Bradford L. Currier, MD1; Brett for patients with cervical compressive myelopathy due to multiple A. Freedman, MD1; Benjamin D. Elder, MD, PhD1; Gregory D. spinal stenosis caused by cervical spondylosis (CS) or ossification Schroeder, MD3; Alexander R. Vaccaro, MD, PhD4; Scott Wagner, of the posterior longitudinal ligament (OPLL). However, there is no MD5; Ian D. Kaye, MD4; Arjun S. Sebastian, MD, MSc1 follow-up report exceeding 20 years after cervical laminoplasty. 1Mayo Clinic, Rochester, MN, US; 2Mayo Clinic/Dept of Orthopedic PURPOSE: The purpose of the study was to evaluate the clinical Surgery, Rochester, MN, US; 3Rothman Institute Thomas Jefferson outcomes and to clarify the potential risks of cervical laminoplasty University, Philadelphia, PA, US; 4Rothman Institute, Philadelphia, by a long-term follow-up of more than 20 years. PA, US; 5Walter Reed National Military Medical Center, Bethesda, STUDY DESIGN/SETTING: Retrospective study. MD, US PATIENT SAMPLE: Two hundred and sixteen patients underwent BACKGROUND CONTEXT: Recent literature has examined the en bloc cervical laminoplasty for the treatment of cervical importance of cervical alignment with regards to health related compressive myelopathy due to CS or OPLL between 1981 and quality of life outcomes. Several clinical alignment parameters have 1994 in our univeristy hospital. Of these, 148 patients with a follow- been identified as potential goals for correction of cervical spinal up of more than 20 years were subjected to this study. Eighty deformities. Of these parameters, the C2-7 SVA has been utilized patients have already died at the follow-up. Follow-up rate was as a measure of global cervical alignment, and previous work has 68.5% (148/216). suggested that achieving a postoperative SVA of 4cm or les is ideal OUTCOME MEASURES: The neurological evaluation was graded with regards to patient outcomes. using the scale devised by the Japanese Orthopaedic Association PURPOSE: The purpose of this study was to determine the impact (JOA score) and the recovery rate. Radiological examinations were of SVA on postoperative neck pain scores after posterior cervical carried out using pre- and post-operative plain X-ray. As for the laminectomy and fusion for myelopathy. dead patients by the final follow-up, the cause and age of death STUDY DESIGN/SETTING: We performed a retrospective review of was reviewed by the medical record or by directly questioning the a prospective cohort. family members. PATIENT SAMPLE: Our patient sample included patients METHODS: Retrospectively collected data were analyzed. Data undergoing posterior cervical laminectomy and fusion from C2-T2 were presented as the mean value ± standard deviation. A t - test for subaxial cervical stenosis and degenerative cervical myelopathy with Welch's correction was used for the statistical analysis of the from 2011-2019. difference in the mean age between the worsening group and the OUTCOME MEASURES: Visual analog scores (neck) non-worsening group. Chi-square test was used for the analysis of METHODS: We performed a retrospective review of a multicenter the incidence of additional spine surgery between the worsening prospective cohort of patients undergoing posterior cervical group and the non-worsening group. The radiological parameters laminectomy and fusion from C2-T2 for subaxial cervical stenosis were compared between cervical spondylosis (CS) and OPLL using and degenerative cervical myelopathy from 2011-2019. We a t - test with Welch's correction. collected demographic information and assessed cervical RESULTS: The JOA score and recovery rate increased to 14.2 and alignment on standing radiographs performed preoperatively 64.9%, respectively, at 5 years after surgery. The mean JOA score as well as at 6 months or greater postoperatively. The cohort and recovery rate were maintained at 13.9 and 61.6% at 10 years. was divided into 2 groups based on a postoperative SVA of less The JOA score decreased to 11.4 at the last follow-up. In 32 out of than 4 cm or 4cm or greater based on established criteria. We 65 patients (49.2%), the JOA scores worsened during the follow-up then examined differences between the groups with regards period. Ten patients had neurological deterioration and required to preoperative and postoperative alignment, demographics, additional spine surgeries. The main cause of the additional surgery and neck pain scores as measured by the visual analog scale. was progression of OPLL. Cervical alignment became kyphotic after A univariate analysis was performed to assess for differences surgery. The mean ROM of the cervical spine decreased and one between the 2 groups. All statistical analyses were performed with of the causes of ROM reduction was postoperative interlaminar JMP Pro 14.1.0. fusion. Regarding the 80 patients who died during follow-up, the RESULTS: 173 patients were identified for inclusion. In this cohort, mean age at death was 78.2 ± 8.6 years. No patient died from 70 patients were identified as having a postoperative SVA less than complications related to the operation. The most frequent cause of 4cm and 103 patients were identified as having an SVA of 4cm death was malignant tumor. or greater. In both groups, the change in SVA showed worsening Proceedings 27

of alignment. This was significantly higher in the SVA > 4 cohort METHODS: Cervical alignment parameters were measured on both compared to the SVA < 4 cohort (-11.6 vs -3.3, p<.001). There preoperative and postoperative radiographs performed greater was also a significantly higher proportion of female patients in the than 6 months postoperatively. The cohorts were compared based SVA <4 cohort (54.3% vs 30.1%). Otherwise, there were no other upon preoperative cervical alignment, postoperative cervical significant differences in demographics between the 2 groups alignment, and change in cervical alignment. Postoperative (Table 1). Of the 173 patients, 108 patients (62.4%) had VAS neck radiographs were also assessed for signs of distal screw loosening, pain scores recorded at greater than 6 months postoperatively. distal junctional failure, and pseudarthrosis. We utilized Student’s With regards to VAS neck pain scores, they improved in both t-test to compare all means between groups with p<0.05 deemed groups with long-term follow up (Table 2). There was no significant statistically significant. difference between the cohorts with respect to neck pain scores at RESULTS: A total of 155 patients were included in the study (C2- any time point. Using the established minimal clinically important T2: 106 patients, C3-T1: 49 patients). There were no significant difference for VAS neck pain following cervical surgery, we found differences in demographics or preoperative symptoms between that 61.9% of the SVA < 4 cohort and 52.9% of the SVA > 4 cohort cohorts. Fusion rates were significantly higher in the C2-T2 (93%) achieved MCID with no significant difference between the groups than the C3-T1 (80%, p=0.040) cohort. When comparing the C2-T2 (p=.432). to the C3-T1 cohort, the C3-T1 cohort had a significantly greater CONCLUSIONS: The primary goal for posterior cervical rate of proximal junctional failure (2% vs. 10%, p=0.006), distal laminectomy and fusion in the treatment of degenerative junctional failure (1% vs. 20%, p<0.001) and distal screw loosening myelopathy is to achieve adequate decompression of the spinal (4% vs. 15%, p=0.02). Although ∆C2-7 Sagittal vertical axis cord and a stable, fused spine. While previous work has established increased significantly in both cohorts (C2-T2: 6.2º, p=0.04; C3- the importance of SVA alignment in treatment of cervical deformity, T1: 8.4º, p<0.001), correction did not significantly differ between in this multi-center cohort of patients undergoing C2-T2 posterior groups (p=0.32). The C3-T1 cohort had a significantly greater cervical fusion for degenerative myelopathy, postoperative SVA > increase in ∆C2 Slope (8.0o vs 3.1o, p=0.03) and ∆C0-C2 Cobb 4cm was not associated with a significant difference in long-term angle (6.4º vs 1.2º, p=0.04) patient reported outcomes with regards to neck pain. CONCLUSIONS: In patients undergoing PCF, a C2-T2 construct FDA DEVICE/DRUG STATUS: This abstract does not discuss or demonstrated lower rates of pseudarthrosis, DJF, PJF, and include any applicable devices or drugs. compensatory upper cervical hyperextension compared to a C3-T1 construct. FDA DEVICE/DRUG STATUS: This abstract does not discuss or 3. Cervical alignment and distal junctional failure in include any applicable devices or drugs. posterior cervical fusion: A multicenter comparison of two surgical approaches 4. Change in postoperative intervertebral space Zachariah Pinter, MD1; Arjun S. Sebastian, MD, MS1; Jad Bou Monsef, MD2; Daniel R. Bowles, MD3; Ashley Xiong, CCRC1; height and its impact on clinical and radiological Bradford L. Currier, MD1; Ahmad N. Nassr, MD4; Brett A. Freedman, outcomes after ACDF surgery with zero profile device MD1; Mohamad Bydon, MD1; Benjamin D. Elder, MD, PhD1; Haimiti Abudouaini, MD 5 5 Christopher K. Kepler, MD, MBA ; Alexander R. Vaccaro, MD, PhD ; West China Hospital, Sichuan University, Chengdu, China Ian D. Kaye, MD5; Scott Wagner, MD6 BACKGROUND CONTEXT: Intervertebral space height (ISH) 1 2 Mayo Clinic, Rochester, MN, US; SUNY Downstate, Brooklyn, NY, narrowing is a pathological change that occurs during cervical 3 4 US; Northwell Health, New Hyde Park, NY, US; Mayo Clinic/Dept degenerative disc disease. Spinal surgery aims to correct ISH via 5 of Orthopedic Surgery, Rochester, MN, US; Rothman Institute, ideal intraoperative distraction and postoperative intervertebral 6 Philadelphia, PA, US; Walter Reed National Military Medical space maintenance. However, the effects of postoperative ISH Center, Bethesda, MD, US changes on clinical and radiological outcomes after anterior BACKGROUND CONTEXT: Posterior cervical fusion (PCF) is cervical decompression and fusion (ACDF) surgery with Zero- successfully used to treat cervical spondylotic myelopathy, profile are not well understood. multilevel cervical stenosis, and cervical deformity. However, PURPOSE: To determine the ISH changes following ACDF with limited evidence exists regarding the appropriate level of proximal Zero-profile and analyzed the relationship between ISH and clinical and distal extension of PCF constructs. Further investigation is efficacy and imaging parameters. required to understand the effects of construct endpoint on fusion STUDY DESIGN/SETTING: This is an observational study. rate, junctional failure, and sagittal deformity correction. PATIENT SAMPLE: A total of 138 patients were reviewed. PURPOSE: To compare the surgical and radiographic outcomes of OUTCOME MEASURES: The Japanese Orthopedics Association patients undergoing posterior cervical fusion (PCF) with constructs (JOA), Visual Analogue Scale (VAS), and Neck Disability Index (NDI) extending from C2-T2 to patients with constructs extending from scores, visual analogue scale (VAS) were evaluated. Intervertebral C3-T1. space height, cervical global and segmental lordosis, fusion rate, STUDY DESIGN/SETTING: This was a multicenter retrospective diameter of intervertebral foramen (IVF) incidence of subsidence, review of two prospective cohorts of patients undergoing PCF dysphagia, and adjacent segment degeneration were measured. from C2-T2 or C3-T1 for subaxial cervical stenosis at two academic METHODS: We retrospectively reviewed patients who underwent institutions from 2012 to 2020. ACDF with Zero-profile from March 2012 to February 2016 at PATIENT SAMPLE: We identified 106 patients for inclusion in the our institution. First, intervertebral height variation and overall C2-T2 cohort and 49 patients for inclusion in the C3-T1 cohort. postoperative ISH trends were analyzed in all patients. Based on OUTCOME MEASURES: Pre- and postoperative cervical alginment postoperative ISH, they were divided into group A (ISH = <2mm), parameters, distal screw loosening, distal junctional failure, and group B (ISH = 2-4mm, and group C (ISH = >4mm). Next, JOA, pseudoarthrosis were measured. NDI, VAS, cervical lordosis, fusion rate, diameter of intervertebral Proceedings 28

foramen (IVF) incidence of subsidence, dysphagia, and adjacent STUDY DESIGN/SETTING: Retrospective cohort study. segment degeneration were compared across the 3 groups. PATIENT SAMPLE: Consecutive patients with CSM who RESULTS: The mean ISH was significantly elevated from 6.72mm required surgical treatment were enrolled. All enrolled patients before surgery to 10.46mm at one week before gradually reducing (n = 78) underwent CMEL or ELAP. All patients were followed to 9.58, 8.73, 7.58, and 7.48mm at 3 months, six months, one postoperatively for more than 5 years. year, and final follow-up, respectively. There were no significant OUTCOME MEASURES: The preoperative and 5-year follow- differences with regards to preoperative baseline characteristics up evaluations included neurological assessment (Japanese and postoperative clinical outcomes between the 3 groups. The Orthopaedic Association [JOA] score), JOA recovery rates, axial average fusion rate was 61.90% in group A, 63.23% in group B, neck pain (using a visual analog scale), the SF-36, and cervical and 53.57% in group C at 3 months, 73.81% in group A, 79.41% sagittal alignment (C2–7 subaxial cervical angle). in group B, and 67.86% in group C at 6 months, and 90.48% in METHODS: All parameters were analyzed statistically, with the group A, 95.59% in group B, and 92.86% in group C at one year level of significance set at p < 0.05. The Student’s t-test was after surgery. The mean diameter of IVF was 6.52±1.80mm in used to compare preoperative and postoperative JOA scores, group A, 9.55±2.36mm in group B, and 9.34±1.62mm in group recovery rates, SF-36 and VAS between the CMEL and ELAP C. Degeneration at the superiorly and inferiorly adjacent disc level groups. The subaxial cervical lordosis (C2-7 Cobb’ angle) on lateral affected 11.90% and 16.67% patients in group A, 5.88% and radiograph was also compared using Student’s t-test. 7.38% in group B, and 14.28% and 10.71% in group C.In the 3 RESULTS: Sixty-one patients were included for analysis, 31 in the groups, while implant subsidence had a rate of 7.14%, 4.41%, and CMEL group and 30 in the ELAP group. The mean preoperative 14.29%. JOA score was 10.1 points in the CMEL group and 10.9 points in CONCLUSIONS: We find that ACDF surgery with Zero-profile the ELAP group (p > 0.05). The JOA recovery rates were similar, device does not sustain the intervertebral disc height attained 57.6% in the CMEL group and 55.4% in the ELAP group (p > 0.05). immediately after surgery. There was no clear correlation between The axial neck pain in the CMEL group was significantly lower than intervertebral space height change and clinical efficacy within that in the ELAP group (p < 0.01). At the 5-year follow-up, cervical a year of surgery. However, intervertebral disc height may affect alignment was more favorable in the CMEL group, with an average various complications one year after surgery. If postoperative 2.9° gain in lordosis (versus 1.2° loss of lordosis in the ELAP group intervertebral space height change is maintained at 2-4mm in a [p < 0.05]) and lower incidence of postoperative kyphosis. year, satisfactory fusion rate, intervertebral foramen diameter, and CONCLUSIONS: CMEL is a novel, less invasive technique that relatively low ASD and implant subsidence may be achieved after allows for multilevel posterior cervical decompression for the ACDF surgery with Zero-profile device. treatment of CSM. This 5-year follow-up data demonstrates FDA DEVICE/DRUG STATUS: This abstract does not discuss or that after undergoing CMEL, patients have similar neurological include any applicable devices or drugs. outcomes to conventional laminoplasty, with significantly less postoperative axial pain and improved subaxial cervical lordosis when compared with their traditional ELAP counterparts. 5. Microendoscopic laminotomy versus conventional FDA DEVICE/DRUG STATUS: This abstract does not discuss or laminoplasty for cervical spondylotic myelopathy: A include any applicable devices or drugs. 5 year follow up study

Akihito Minamide, MD, PhD1; Andrew Simpson, MD2; Yasutsugu 6. Physical and mental well-being improvements Yukawa, MD, PhD3; Hiroshi Hashizume, MD, PhD3; Yutaka Nohara, after surgery for cervical spondylotic myelopathy MD4; Hiroshi Yamada, MD, PhD5 Koji Tamai, MD1; Akinobu Suzuki, MD, PhD1; Hidetomi Terai, MD, 1Dokkyo Medical University Nikko Medical Center, Nikko, Tochigi, PhD2; Masatoshi Hoshino, MD2; Hiromitsu Toyoda, MD, PhD1; Japan; 2Brigham and Women's Hospital, Dept of Orthopedic Shinji Takahashi, MD1; Yusuke Hori, MD4; Akito Yabu, MD3; Hiroaki Surgery, Boston, MA, US; 3Wakayama, Japan; 4Nagareyama Nakamura, MD, PhD4 Chuoh Hospital, Nagareyama, Chiba, Japan; 5Wakayama Medical 1Osaka City University, Osaka, Japan; 2Dept. of Orthopaedic University, Dept. of Orthopaedic Surgery, Wakayama, Japan Surgery, Osaka City University, Graduate School of Medicine, BACKGROUND CONTEXT: The spinal cord compression Osaka, Japan; 3Ishikiriseiki Hospital, Higashiosaka, Japan; 4Osaka in the cervical spondylotic myelopathy (CSM) consists of a City University, Graduate School of Medicine, Osaka, Japan pincer mechanism due to a bulging disc and a hypertrophied BACKGROUND CONTEXT: Spinal surgeons should understand ligamentum flavum. The long-term clinical benefits of segmental the postoperative course in detail. However, data is still needed decompression surgery, which removes the dorsal compressive regarding the time-course of improvements in well-being, a elements of articular segment in CSM patients, have not yet been fundamental aspect of human life, after cervical surgery for cervical elucidated. The concept of cervical microendoscopic laminotomy spondylotic myelopathy (CSM). (CMEL) is the relief of pincer mechanism due to remove the PURPOSE: The primary aim of this study is to elucidate the dorsal compressive elements of the articular segment. CMEL is a postoperative time-course of physical and mental well-being minimally invasive spine surgery using endoscpe, and may provide improvements in patients with cervical spondylotic myelopathy. In some benefit with regard to maintaining lordosis and decreasing addition, the secondry aim is to identify the preoperative factors axial symptoms. associated with improvement. PURPOSE: The goal of this study was to characterize the long- STUDY DESIGN/SETTING: Retrospective cohort study term clinical and radiological results of articular segmental PATIENT SAMPLE: One hundred consecutive patients who decompression surgery using endoscopy (CMEL) for CSM and to underwent laminoplasty for CSM, with complete clinical data compare outcomes to conventional expansive laminoplasty (ELAP). preoperatively and 3 months and 2 years postoperatively, were enrolled. Proceedings 29

OUTCOME MEASURES: Clinical scores, including the cervical 8. Residual neuropathic pain in postoperative Japanese Orthopedic Association (cJOA) and Short Form-36 patients for cervical ossification of posterior (SF-36) scores, were recorded preoperatively and at 3 months, 1 year, and 2 years postoperatively. The SF-36 physical component longitudinal ligament summary (PCS) and mental component summary (MCS) scores Masayuki Miyagi, MD, PhD1; Toshitaka Yoshii, MD2; Masao Koda, were used as parameters of physical and mental well-being, MD, PhD3; Takeo Furuya, MD, PhD3; Atsushi Kimura, MD, PhD4; respectively, and 4.0 was defined as the minimal clinically Narihito Nagoshi, MD, PhD5; Hiroaki Nakashima, MD6; Gen Inoue, important difference (MCID) for both parameters. MD, PhD7; Shiro Imagama, MD8; Katsushi Takeshita, MD, PhD9; METHODS: Individual change analysis. We determined the Morio Matsumoto, MD10; Atsushi Okawa, MD, PhD11; Masashi number of patients who achieved an improvement in the PCS Yamazaki, MD, PhD12; Takaso Masashi, MD, PhD13 and MCS greater than the MCID at 3 months and 2 years 1Kitasato University, School of Medicine, Sagamihara, Japan; postoperatively. For the PCS and MCS each, patients who achieved 2Tokyo Medical & Dental University, Tokyo, Japan; 3Department an improvement greater than the MCID at both 3 months and of Orthopaedic Surgery, Chiba University Graduate School 2 years postoperatively were considered to have “maintained of Medicine, Chiba, Japan; 4Jichi Medical University, Tochigi, improvement”. Additionally, patients failed to achieve an Japan; 5Toronto Western Hospital, Toronto, ON, Canada; 6Nagoya improvement greater than the MCID at 3 months, but achieved an University Graduate School of Medicine, Department of Orthopedic improvement greater than MCID at 2 years postoperatively were Surgery, Nagoya, Japan; 7Kitasato University, School of Medicine, considered to have “late improvement”. The chi-squared test was Dept of Orthopaedic Surgery, Sagamihara, Kanagawa, Japan; used to evaluate differences between the PCS and MCS in the 8Nagoya University Graduate School of Medicine, Nagoya, Japan; numbers of patients with an improvement greater than the MCID 9Department of Orthopaedic Surgery, Jichi Medical University, at 3 months postoperative, maintained improvement, and late Tochigi, Japan; 10Keio University School of Medicine, Tokyo, Japan; improvement. Analysis of the factors associated with improvement 11Bunkyo-Ku, Japan; 12Department of Orthopaedic Surgery, Faculty in PCS and MCS scores. The Pearson correlation coefficient of Medicine, University of Tsukuba, Tsukuba, Japan; 13Kitazato was used to evaluate associations between improvement in University, School of Medicine, Sagamihara-shi, Japan PCS and MCS scores, and age and the improvement in cJOA score. Subsequently, multivariate liner regression analyses BACKGROUND CONTEXT: Cervical ossification of posterior were performed, with the change in PCS or MCS scores (from longitudinal ligament (c-OPLL) patients complained numbness the preoperative value to the value at 3 months or 2 years and paralysis of the upper and lower limbs and sometimes need postoperatively) set as the objective variable, and age, sex, and surgery, but often remains spinal neuropathic pain postoperatively, change in cJOA score (from the preoperative value to the value at resulting in deteriorate quality of life. 3 months or 2 years postoperatively) were included as explanatory PURPOSE: To elucidate residual or deterioration pain after surgery variables, adjusting for these variables. Unstandardized partial for c-OPLL and clarify these risk factors by multivariate analysis. regression coefficients(B), standardized partial regression STUDY DESIGN/SETTING: Multicenter prospective observational study. coefficients(β), and p-values were calculated. RESULTS: On average, PCS and MCS scores were significantly PATIENT SAMPLE: Among 479 patients registered in multicenter improved after surgery (p<0.001, p=0.004, respectively). c-OPLL registry, excluding patients with comorbidities that affect Moreover,64 and 48 patients achieved meaningful improvement neurological symptoms such as medical history of thoracolumbar (>MCID) in PCS and MCS scores at 3 months postoperatively, with spinal surgery and cerebrovascular disease, remaining 292 maintained improvement (to 2 years) in 46/64 (71.9%) and 34/48 patients who could be followed up for 2 years after surgery were patients (70.8%), respectively (PCS vs MCS: p=0.912). Additionally, included. 15/36 patients (41.7%) and 8/52 patients (15.4%) achieved OUTCOME MEASURES: We reviewed age at the surgery, gender, late improvement (meaningful improvement at 2 years but not BMI, the presence of diabetes, radiographical factors including at 3 months) in PCS and MCS scores, respectively (PCS vs MCS: K-line, spinal canal occupancy rate of OPLL, cervical kyphosis p=0.007). On multivariate regression analysis, myelopathy recovery angle (C2-7) and the presence of spinal cord myelomalacia, was significantly associated with PCS improvement, but not MCS preoperative JOA score, duration of illness, surgical procedure improvement, at both 3 months and 2 years (p=0.001, p>0.001, (fusion or decompression surgery), the presence of postoperative respectively). neurological symptom deterioration and the visual analogue scale CONCLUSIONS: The overall outcome of physical well-being (VAS) of pain and numbness in the upper limbs or trunk / lower improvement is decided within 3 months postoperatively, in limbs before and 2 years after surgery. proportion tothe recovery in myelopathy, with a relatively high METHODS: We defined the postoperative VAS is 40 mm or more chance of meaningful improvement over the next 21 months. as residual and the deterioration of 20% or more compared to The outcome of mental well-being improvement is decided within preoperative VAS as deterioration. Each measurements were 3 months postoperatively, independently from the recovery in compared between residual group and non-residual group or myelopathy, with a low chance of meaningful improvement over the deterioration group and non-derioration group, additionally, the next 21 months. risk factors for residual or deterioration neuropathic pain were FDA DEVICE/DRUG STATUS: This abstract does not discuss or evaluated by multiple logistic regression analysis. include any applicable devices or drugs. RESULTS: As a result of comparison between the two groups, the residual group of upper limbs had a poor preoperative JOA score and a long illness duration, and there was more fusion 7. Moved to Cervical Stenosis and Ossification surgery in residual group compared with that in non-residual group. The residual group of lower limbs was higer age and had a of Posterior Longitudinal Ligament (OPLL) with poor preoperative JOA score. In the deterioration group of lower Myelopathy limbs, the spinal canal occupancy rate was higher, and there were more cases with the deterioration of neurological symptoms Proceedings 30

postoperatively compared with in non-deterioration group. In the 21.03-28.42, p<0.001). Specifically for VAS neck, the mean delta multivariate analysis, potential risk factors of residual pain in upper improvement in conventional PCF was 3.74 (95%CI 2.89-4.59) limb were long illness duration, poor preoperative JOA score, and versus 4.07 (95%CI 2.83-5.31) in MI-PCF (p=0.66). potential risk factors of residual pain in lower limb were ageing and CONCLUSIONS: Contrary to popular belief, patients undergoing poor preoperative JOA score poor. Further, potential risk factors posterior cervical foraminotomy can expect to have improvement of deterioration pain in upper limb were long illness duration, and in their neck pain. Moreover, patients undergoing MI-PCF may potential risk factors of deterioration pain in lower limb were high experience a greater improvement in neck pain compared to open spinal canal occupancy rate and the deterioration of neurological techniques. symptoms postoperatively. FDA DEVICE/DRUG STATUS: This abstract does not discuss or CONCLUSIONS: These findings indicated the risk factors for include any applicable devices or drugs. residual spinal neuropathic pain after c-OPLL surgery were aging, long duration of illness, and poor preoperative JOA score. In addition, the risk factors for deterioration were long duration 10. Comparison of patient-reported postoperative of illness, high spinal canal occupancy and the deterioration of dysphagia in patients undergoing one-level versus neurological symptoms postoperratively. two-level anterior cervical discectomy and fusion FDA DEVICE/DRUG STATUS: This abstract does not discuss or with the Zero-P Implant System include any applicable devices or drugs. Chengyi Huang, MD, PhD Department of Orthopedics, West China Hospital, Sichuan 9. The impact of posterior cervical foraminotomy on University, Chengdu, Sichuan, China neck pain: A systematic review and meta-analysis BACKGROUND CONTEXT: We noticed that after the ACDF with Hikari Urakawa1; Kosuke Sato, MD2; Avani S. Vaishnav, MBBS1; Zero-P, the changes of lordosis in some patients are obvious, Bridget Jivanelli, MS, BA2; Catherine Himo Gang, MPH1; Sheeraz A. especially the C2-7 angle, and these could cause changes in Qureshi, MD, MBA1 the anatomical relationship between the cervical spine and 1Hospital for Special Surgery, New York, NY, US; 2New York, NY, US the anterior esophagus, which may cause dysphagia. However, there have been few reports describing the effect of difference BACKGROUND CONTEXT: Posterior cervical foraminotomy (PCF) between postoperative and preoperative C2-7 angle (dC2-7A) on is a safe and reasonable surgical treatment option for cervical postoperative dysphagia after ACDF with Zero-P. radiculopathy. There are a plethora of studies evaluating the PURPOSE: To investigate the effect of the difference in C2-7 angle improvement of radiculopathy, but very few studies report on the on dysphagia after anterior cervical discectomy and fusion (ACDF) impact of the procedure on neck pain. with the Zero-P Implant System. PURPOSE: To elucidate the impact of PCF on neck pain. STUDY DESIGN/SETTING: A retrospective analysis. STUDY DESIGN/SETTING: Systematic review and meta-analysis PATIENT SAMPLE: In total, 181 consecutive patients were enrolled OUTCOME MEASURES: Visual analog scale (VAS) at neck and in this study according to the inclusion and exclusion criteria. The neck disability index (NDI). dysphagia group consisted of 42 consecutive patients while the METHODS: A systematic review and meta-analysis was performed non-dysphagia group consisted of 139 consecutive patients. based on rules set forth by preferred reporting items for systematic OUTCOME MEASURES: The difference between postoperative reviews and meta-analysis (PRISMA). A comprehensive literature and preoperative C2–7 angle (dC2–7A), the difference between search was performed in PubMed/ MEDLINE, EMBASE and postoperative and preoperative O-C2 angle (dO-C2A), sex, age, the Cochrane Library, using Medical Subject Heading terms body mass index(BMI), intraoperative time, estimated blood loss, (“neck” and “foraminotomy”) and associated text words. The diabetes mellitus, hypertension, smoking, alcohol consumption, search strategy was created by one author and one librarian. Two prevertebral soft-tissue swelling (PSTS), the highest segment authors independently reviewed all articles and identified studies involved in the surgery and the levels of surgery segments. presenting clinical outcomes including visual analog scale (VAS) METHODS: A retrospective analysis of 181 patients who at neck or neck disability index (NDI) for patients who underwent underwent ACDF with the Zero-P Implant System and had at PCF for cervical radiculopathy. Exclusion criteria included patients least one year of follow-up was performed from January 2011 to who had surgery for myelopathy or non-degenerative cervical November 2018. All patients were divided into a non-dysphagia diseases or who underwent PCF in conjunction with laminoplasty group and a dysphagia group to explore the effect of difference or laminectomy with or without fusion. We also excluded studies between postoperative and preoperative C2-7 angle (dC2-7A) that did not provide both pre- and postoperative outcomes, were on postoperative dysphagia. At the same time, other possible not written in the English language, or were review articles or case related factors including the difference between postoperative reports of less than 10 patients. Meta-analysis was performed with and preoperative O-C2 angle (dO-C2A), sex, age, body mass index studies that provided means with standard deviations of VAS and (BMI), intraoperative time, estimated blood loss, diabetes mellitus, NDI. hypertension, smoking, alcohol consumption, prevertebral soft- RESULTS: The initial literature search resulted in 766 articles, tissue swelling (PSTS), the highest segment involved in the surgery of which, 30 studies met inclusion criteria. VAS neck and NDI and the levels of surgery segments were analyzed. improved after PCF in all studies. 11 studies (14 cohorts) with RESULTS: There were 139 patients in the non-dysphagia group 366 patients were included in meta-analysis. The mean follow-up and 42 patients in the dysphagia group. The single-factor analysis period was 27.1 months. Minimally invasive techniques for PCF showed smoking, PSTS and dC2-7A was significantly different (MI-PCF) were used in 9 articles. The mean delta improvement between two groups (P<0.05). Spearman’s correlation coefficient of VAS neck was 3.99 (95%CI 2.92-5.07, p<0.001). The mean showed no significant correlation between degree of dysphagia delta improvement of VAS arm was 5.73 (95%CI 5.25-6.22, and dC2-7A (P>0.05). The results of multiple-factor analysis with p<0.001). The mean delta improvement of NDI was 24.72 (95%CI an ordinal logistic regression model showed that smoking, PSTS Proceedings 31

and dC2-7A were significantly associated with the incidence of BACKGROUND CONTEXT: The concept of frailty has become dysphagia (P<0.05). increasingly recognized, and while patients with cancer are at CONCLUSIONS: The postoperative C2-7 angle has an important increased risk for frailty, its influence on perioperative outcomes in effect on the occurrence of dysphagia in patients undergoing metastatic spine tumors is uncertain. Furthermore, the impact of Zero-P implant system interbody fusion surgery. frailty can be confounded by comorbidities or metastatic disease FDA DEVICE/DRUG STATUS: This abstract does not discuss or burden. include any applicable devices or drugs. PURPOSE: The purpose of this study was to evaluate the influence of frailty and comorbidities on adverse outcomes in the surgical management of metastatic spine disease. Monday, July 5 STUDY DESIGN/SETTING: Retrospective cohort study. 4:00–5:30 p.m. PATIENT SAMPLE: 7,772 patients underwent spinal fusion with spinal metastasis within the Nationwide Readmissions Database Complications (NRD). OUTCOME MEASURES: Mortality, medical complications, 11. Perioperative risk stratification in elective surgical complications, increased length of stay (LOS), nonroutine orthopaedic spine surgery: A systematic review discharge, increased costs. Hao-Hua Wu, MD1; Andrew Logan, MD2; Steven Wright, BS3; Lionel METHODS: A validated binary frailty index (Johns Hopkins Adjusted N. Metz, MD4 Clinical Groups) was used to identify frail and non-frail groups, and propensity score-matched analysis (including demographics, 1San Francisco, CA, US; 2Jackson - PM&R, Miami, FL, US; comorbidities, surgical and tumor characteristics) was performed. 3California Northstate University, Elk Grove, CA, US; 4UCSF Dept. of Sub-group analysis of levels involved was performed for cervical, Orthopaedic Surgery, San Francisco, CA, US thoracic, lumbar and junctional spine. Outcomes analyzed PURPOSE: The purpose of this review is to evaluate the current included mortality, complications, length of stay (LOS), nonroutine methods of predicting postoperative complications and to provide discharges and costs. Multivariable-regression techniques were physicians with evidence-based guidance on risk stratification for used to develop predictive models for outcomes using frailty and the adults undergoing elective spine surgery. Elixhauser Comorbidity Index (ECI). STUDY DESIGN/SETTING: Systematic review. RESULTS: 7,772 patients underwent spinal fusion with spinal METHODS: In this systematic review, keywords associated with metastasis, of which 1,974 (25.4%) patients were identified as frail. perioperative risk assessment and spine surgery were searched Following propensity score matching for frail (n= 1,974) and not-frail in PubMed from January 2000 through July 2016. Articles with (n=1,975) groups, frailty demonstrated significantly greater medical pediatric patients, cervical spine surgery or psychologic or complications (OR=1.58; 95% CI 1.33-1.86), surgical complications psychiatric effects on surgical outcomes were excluded. (OR=1.46; 95% CI 1.15-1.85), LOS (OR=2.65; 95% CI 2.09-3.37), RESULTS: A total of 21 peer-reviewed articles were identified. nonroutine discharges (OR=1.79; 95% CI 1.46-2.20) and costs Risk factors associated with an increased risk of postoperative (OR=1.68; 95% CI 1.32-2.14). Differences in mortality were only complications were age, American Society of Anesthesiologists observed in subgroup analysis and were greater in frail junctional classification (ASA), recent inpatient admissions, anemia, obesity, and lumbar spine subgroups. Models using ECI alone (AUC= 0.636- metabolic syndrome, sleep apnea, renal impairment, hospital 0.788) demonstrated greater predictive ability compared to those volume, and insurance status. using frailty alone (AUC=0.633-0.752). However, frailty combined CONCLUSIONS: Postoperative complications following elective with ECI improved the prediction of increased LOS (AUC=0.811), spine surgery are a critical concern for both patients and cost (AUC=0.768), medical complications (AUC=0.723) and physicians. Yet, there remains a need for a clinically validated nonroutine discharges (AUC=0.718). Predictive modeling of frailty risk stratification tool to predict complications after elective in subgroups demonstrated the greatest performance for mortality orthopaedic procedures. Data from this review can be used to (AUC=0.750) in the lumbar spine, otherwise performed similarly for identify the key variables that need to be included in such a risk LOS, costs, complications, and discharge across subgroups. stratification tool. CONCLUSIONS: A high prevalence of frailty existed in the FDA DEVICE/DRUG STATUS: This abstract does not discuss or current patient cohort. Frailty contributed to worse short-term include any applicable devices or drugs. adverse outcomes and could be more influential in the lumbar and junctional spine due to higher risk of deconditioning in the postoperative period. Predictions for short term outcomes can be 12. The performance of frailty in predictive modeling improved by adding frailty to comorbidity indices, suggesting a of short-term outcomes in the surgical management more comprehensive preoperative risk stratification should include of metastatic tumors to the spine frailty. FDA DEVICE/DRUG STATUS: This abstract does not discuss or Shane Shahrestani, MS2; Joshua Bakhsheshian, MD, MS1; Zorica include any applicable devices or drugs. Buser, PhD2; Raymond J. Hah, MD3; Patrick C. Hsieh, MD, MS4; John C. Liu, MD5; Jeffrey C. Wang, MD6 1USC - Neurosurgery Dept, Los Angeles, CA, US; 2Keck School of Medicine, University of Southern California, Los Angeles, CA, US; 3Department of Orthopedic Surgery, Keio University School of Medicine, Los Angeles, CA, US; 4Department of Neurological Surgery, Los Angeles, CA, US; 5USC Spine Center and Dept of Neurosurgery, Los Angeles, CA, US; 6USC Spine Center, Los Angeles, CA, US Proceedings 32

13. Acute colonic pseudo-obstruction (Ogilvie factors, symptoms, and potential complications related to OS is critical to aid in decreasing the significant morbidity associated Syndrome) following primary spinal fusion: An with its development. analysis of outcomes and risk factors from 2005 FDA DEVICE/DRUG STATUS: This abstract does not discuss or to 2014 include any applicable devices or drugs. Don Y. Park, MD1; Clark J. Chen, MD2; Peter P. Hsiue, MD3; Elizabeth L. Lord, MD4; Alexandra Stavrakis, MD4 1UCLA, Santa Monica, CA, US; 2University of California, Los 14. Sarcopenia predicts perioperative adverse Angeles, Los Angeles, CA, US; 3Los Angeles, CA, US; 4Santa events following complex revision surgery for the Monica, CA, US thoracolumbar spine BACKGROUND CONTEXT: Acute colonic pseudo-obstruction, Takashi Hirase, MD, MPH known as Ogilvie syndrome (OS), is a rare but serious condition seen Houston Methodist Hospital, Houston, TX, US in the post-operative period. The development of OS associated with primary spine fusion surgery is poorly understood. BACKGROUND CONTEXT: Sarcopenia measured by psoas muscle PURPOSE: The purpose of this study is to use a large national index (PMI) has been shown to predict perioperative mortality database to evaluate the incidence, risk factors, and outcomes and adverse events (AEs) after various surgical procedures. associated with post-operative OS after primary spine fusion However, this relationship has not been studied in complex revision surgery. thoracolumbar spine surgery. STUDY DESIGN/SETTING: This was an epidemiologic study using PURPOSE: This study aimed to determine the relationship data from the National Inpatient Sample (NIS). between sarcopenia and perioperative AEs among patients PATIENT SAMPLE: Patients in the NIS from 2005-2014 who undergoing complex revision thoracolumbar spine surgery. underwent surgery for primary spinal fusion were included. STUDY DESIGN/SETTING: Retrospective cohort study. OUTCOME MEASURES: Primary outcomes assessed included PATIENT SAMPLE: A retrospective analysis was performed at a postoperative complications, length of stay (LOS), and cost during single institution between May 2016 and February 2020 of patients the index hospitalization. undergoing complex revision thoracolumbar spine surgery by three METHODS: ICD-9 codes were used to identify patients who board certified fellowship-trained orthopaedic spine surgeons. underwent spine fusion surgery. Patients were separated into two OUTCOME MEASURES: Perioperative adverse events including cohorts based on the diagnosis of OS. Outcome measures and post-operative anemia requiring transfusion, cardiac complication, risk factors for cohorts were analyzed using multivariate logistic sepsis, wound complication, delirium, intra-operative dural tear, regression and compared. acute kidney injury, pneumonia, urinary tract infection, urinary RESULTS: Over the 10-year study period, 3,884,395 patients retention, epidural hematoma, and deep vein thrombosis. underwent primary spine fusion surgery. Among these, 0.04% Secondary outcome measures were 30-day readmission rates, developed OS during the index hospitalization, with the greatest 30-day re-operation rates, in-hospital mortality rates, discharge incidence seen in primary fusion involving the thoracic spine disposition, and post-operative length of stay (LOS). (0.15%). OS was more common after posterior spine fusion when METHODS: Sarcopenia was analyzed using PMI, calculated at the compared to anterior approach (0.06% vs 0.02%, p<0.0001). OS L3 vertebral body measured on pre-operative magnetic resonance was more common in spine fusion for spine deformity (0.076% vs imaging (MRI) or computed tomography (CT) normalized to 0.034%, p<0.001). OS patients were more likely to be male (69.6% height2 (mm2/m2). Receiver operating characteristic (ROC) curve vs 46.7%, p<0.001), older (60.6 years vs 55.7 years, p<0.0001), analysis and Youden index were used to determine gender-specific have more comorbidities (p<0.0001), be insured by Medicare PMI cut-off values for predicting perioperative AEs. Sarcopenia was (44.5% vs 33.6%, p=0.0003), and treated at urban teaching defined as PMI below the cut-off values. Complex revision surgery hospitals (65.0% vs 54.1%, p=0.0009). OS patients were more likely was defined as Spine Surgical Invasiveness Index > 10. to require a blood transfusion postoperatively (OR=3.39, 95% CI: RESULTS: 114 consecutive patients were included in the study. 2.51-4.59, p<0.001), sustain any complication (OR=4.20, 95% CI: ROC curve analysis demonstrated PMI < 500 mm2/m2 for males 3.17-5.57, p<0.001), and be discharged to a skilled nursing facility and < 412 mm2/m2 for females as predictors for perioperative AEs. (SNF) (OR=3.02, 95% CI: 2.29-3.99, p<0.001). OS patients were 49 patients were in the sarcopenia cohort and 65 patients in the more likely to develop a surgical site infection (OR=6.18, 95% CI: non-sarcopenia cohort. The sarcopenia group had higher overall 4.07-9.39, p<0.001) and systemic infection (OR=7.06, 95% CI: perioperative AEs (73.5% vs 29.2%, p<0.001) and individual AEs 4.31-11.57, p<0.001). OS patients had a longer LOS (15.7 days including: post-operative anemia requiring transfusion, wound vs 3.9 days, p<0.001) and increased average hospitalization cost complication, delirium, acute kidney injury, pneumonia, urinary ($63,037.03 vs $26,792.19, p<0.001). The development of OS was tract infection, and deep vein thrombosis. The sarcopenia group associated with fluid electrolyte disorder (OR=4.06, 95% CI: 2.99- had higher 30-day reoperation rate (14.3% vs 3.1%, p=0.028), 30- 5.51, p<0.001), congestive heart failure (OR=1.85, 95% CI: 1.14- day readmission rate (16.3% vs 3.1%, p=0.013), rate of discharge 2.99, p=0.013), cardiopulmonary disease (OR=2.17, 95% CI: 1.01- to a facility (83.7% vs 50.8%, p<0.001), and longer length of stay 4.65, p=0.047), lymphoma (OR=2.84, 95% CI: 1.25-6.45, p=0.012) (LOS) (7.3±4.2 days vs 5.6±3.5 days, p=0.029). and cancer metastasis (OR=1.78, 95% CI: 1.01-3.14, p=0.044). CONCLUSIONS: Sarcopenia measured by PMI is associated CONCLUSIONS: OS is a rare but serious complication of primary with higher perioperative AEs, 30-day readmission rates, 30-day spine fusion surgery. Significant medical comorbidities such re-operation rates, rate of discharge to a facility, and longer LOS as cardiopulmonary disease and cancer increased the risk of among patients undergoing complex revision thoracolumbar spine developing OS in our study. This study demonstrated greater risk surgery. of post-operative complications necessitating prolonged hospital FDA DEVICE/DRUG STATUS: This abstract does not discuss or stays with increased associated costs. Identifying the specific risk include any applicable devices or drugs. Proceedings 33

15. Diabetes is associated with greater leg pain and BACKGROUND CONTEXT: Marijuana is an antinociceptive which has been evaluated as a possible adjunct or substitute for worse patient reported outcomes at one year after opioid use in the treatment of acute pain. The aim of this study lumbar spine surgery was to evaluate the association between preoperative marijuana Kosei Nagata, MD1; Yasushi Oshima, MD, PhD2 usage and consumption of opioids for postoperative analgesia. 1The University of Tokyo Hospital, Tokyo, Japan; 2The University of We hypothesized that marijuana usage may be associated with Tokyo, Tokyo, Japan decreased usage of opioid analgesics in postoperative pain relief in patients undergoing spine surgery. BACKGROUND CONTEXT: Patients with diabetes reportedly PURPOSE: To examine the association between marijuana use and show greater back pain and worse patient-reported outcomes opioid consumption in patients undergoing lumbar spine fusion after lumbar spine surgery. However, the effect of diabetes on surgery. postoperative recovery in pain or numbness in buttock, leg, and STUDY DESIGN/SETTING: Retrospective review. plantar region is not well characterized. PATIENT SAMPLE: Two hundred and twenty-one patients who PURPOSE: To elucidate the effect of diabetes on postoperative underwent one- or two-level posterior lumbar interbody fusion recovery in pain/numbness in four body areas (back, buttock, leg, surgery. and plantar) after lumbar spine surgery. OUTCOME MEASURES: Primary outcome measures were STUDY DESIGN/SETTING: Retrospective analysis of prospectively opioid consumption in marijuana users and non-marijuana users collected data. both while in-patient and after discharge as determined by total PATIENT SAMPLE: Patients who underwent decompression morphine equivalent dose (MED). Secondary outcome measures or fixation within three levels of lumbar spine at eight hospitals included operative time, length of stay, discharge destination, and between April 2017 and June 2018. readmission rates. OUTCOME MEASURES: Pre- and postoperative (one-year follow- METHODS: Retrospective review of 221 patients who underwent up) Numerical Rating Scale (NRS) score, Oswestry Disability Index one- or two-level posterior lumbar fusion surgery between 2016 (ODI), and Euro quality of life-5 dimension (EQ-5D) score. and 2020 at a single institution. Patients were categorized as METHODS: Patients were divided into two groups (diabetic and marijuana users or non-marijuana users based on preoperative non-diabetic). Baseline demographic and clinical characteristics diagnoses of marijuana use. Total morphine equivalent dose were compared between the two groups. The inverse probability (MED) was calculated for both in-house opioid consumption and weighted logistic regression model was used to reduce the postoperative prescription opioid usage. Patients who were on influence of covariates by calculating propensity scores based opioids pre-operatively were excluded. Patient demographics on age, sex, body mass index, smoking status, American Society and preoperative characteristics were compared across the BMI of Anesthesiologists classification, operative time, and estimated cohorts using one-way ANOVA and chi-square analysis. blood loss. The percentage of patients who experienced at least RESULTS: Of 221 total patients, 29 patients were identified as 50% relief in pain or numbness was compared between the two marijuana users while 192 were non-marijuana users. There were groups. no significant associations between marijuana usage and age, RESULTS: We analyzed 152 patients (average age: 71 years; ASA, BMI, tobacco use, EBL, OR time, LOS, or disposition to rehab. males 66%) in diabetic group and 841 patients (average age: 66 Marijuana users had greater association with depression (31% years; males 55%) in non-diabetic group. There were no significant vs 12.5%, p=0.032) and 30-day readmission (17.2% vs 11.5% differences in surgical methods, operative time, estimated blood (p<0.001). Marijuana users were found to have increased opioid loss, or incidence of major complications. Preoperative NRS consumption in-house (MED 236.49 vs 166.68, p=0.005), as well scores were comparable in the two groups. The diabetic group as increased postoperative prescription opioid usage (2415.62 vs showed greater postoperative NRS scores for leg pain (3.03 vs 1391.54, p=0.007). 2.45, P value 0.021; adjusted P value 0.013). After adjusting, CONCLUSIONS: Marijuana usage is associated with increased there was significant difference in NRS score for back pain (3.38 usage of opioids postoperatively, both while in patient and post- vs 2.95, adjusted P value 0.046). The diabetic group had worse discharge, after posterior lumbar spine fusion surgery. postoperative ODI/EQ-5D compared with non-diabetic group. A FDA DEVICE/DRUG STATUS: This abstract does not discuss or significant between-group difference with respect to 50% decrease include any applicable devices or drugs. in NRS score was observed only for leg pain. CONCLUSIONS: Our data showed that leg pain relief after lumbar spine surgery was the most affected by diabetes. 17. Risk factors for mechanical complications FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. following the Minimally Invasive Antepsoas (ATP) lumbar and lumbosacral arthrodesis Aziz Saade, MD1; Tony Tannoury, MD2; Rahul A. Bhale, BA3; Qasim 16. Marijuana use is associated with increased use of S. Ajmi, MBBS, FRCS4 prescription opioids following posterior lumbar spine 1Boston Medical Center, Boston, MA, US; 2Boston University School fusion surgery of Medicine, Boston, MA, US; 3Boston, MA, US; 4QAAST1, London, Andrew S. Moon, MD1; Taryn E. LeRoy, MD1; Vahe Yacoubian, United Kingdom BS2; Marissa Gedman, BA, MS2; Jessica P. Aidlen, MD3; Ashley L. BACKGROUND CONTEXT: The emerging minimally invasive Rogerson, MD1 antepsoas (MIS-ATP) approach is gaining momentum as a 1Tufts Medical Center, Boston, MA, US; 2Tufts University School viable access for lumbar interbody fusion. Hardware failure, of Medicine, Boston, MA, US; 3Newton-Wellesley Hospital Spine pseudarthrosis, and adjacent segment disease (ASD) are feared Center, Newton, MA, US mechanical complications that may lead to suboptimal clinical outcomes and need for revision surgery. To date there is not Proceedings 34

sufficient data on the correlation of particular risk factors, such as from 0.3-1.6%. Morbidities associated with infections include obesity (body mass index>30), smoking, diabetes, and prior spine hospital readmissions, reoperations, and long-term antibiotic or abdominal surgeries, with these complications. use. Prophylactic and local administration of vancomycin powder PURPOSE: The primary objective of this study was to evaluate into the wound has been shown to decrease rates of surgical how risk factors (obesity, diabetes, smoking, chronic steroid use, site infections among the adult population, and many pediatric and prior spine or abdominal surgeries) correlate with particular deformity surgeons have adopted its use in an effort to decrease mechanical complications (hardware failure, pseudarthrosis, and infections in the adolescent idiopathic scoliosis population. ASD) following the MIS-ATP technique for lumbar or lumbosacral However, efficacy has not been established in this population. arthrodesis. PURPOSE: The purpose of this study is to investigate the efficacy STUDY DESIGN/SETTING: This is a case-control retrospective of prophylactic, local application of vancomycin powder in study. decreasing surgical site infections in the adolescent idiopathic PATIENT SAMPLE: 272 patients who underwent the MIS-ATP scoliosis population following posterior spinal fusion. approach from 2007 and 2019 at a single institution. STUDY DESIGN/SETTING: Retrospective cohort study OUTCOME MEASURES: Rates of hardware failure, pseudarthrosis PATIENT SAMPLE: Patients <18 years old with a diagnosis of and adjacent segment disease were obtained in correlation with adolescent idiopathic scoliosis, undergoing posterior spinal fusion risk factors (diabetes, smoking, obesity, prior spine surgery and between the years of 2008 and 2019. prior abdominal surgery) OUTCOME MEASURES: Our primary outcome was the incidence METHODS: Following complete ATP discectomies, standard of surgical site infection following posterior spinal fusion. lateral PEEK/carbon fiber composite cages packed with cancellous METHODS: A multicenter, retrospective database query of chips allograft mixed with autologous vertebral bone marrow twenty-one sites belonging to an organization of non-profit medical aspirates were inserted. No additional biologics or bone graft facilities was performed for data from January 2008 to February substitutes were used to enhance fusion, and all patients received 2019. ICD-9, ICD-10, and CPT codes were used to identify percutaneous posterior pedicle-screws-rods fixation. Patient adolescent idiopathic scoliosis patients who underwent posterior charts were reviewed for these risk factors and complications, and spinal fusion. Identified patients were then separated into two appropriate odds-ratio (O.R.) analysis was performed to evaluate groups. The vancomycin cohort had application of prophylactic, potential correlations. local vancomycin into the wound prior to closure and the non- RESULTS: Thirty-six (13.2%) patients experienced hardware vancomycin cohort had no local vancomycin added. Demographic failure, of whom 20 were obese (O.R.=2.4, p=0.2), 8 had type II and surgical data was compiled, as well as microbial data, and SSI diabetes (O.R.=2.1, p=0.4), 5 were smokers (O.R.=4.53, p=0.03), rates were tabulated and compared between the two groups. 12 had prior spine surgeries (O.R.=2.3, p=0.3), and 20 had prior RESULTS: A total of 1,917 adolescent idiopathic scoliosis patients abdominal surgeries (O.R.=5.0, p=0.02). Twenty (7.4%) patients underwent posterior spinal fusion from January 2008 to February experienced pseudarthrosis, of whom 16 were obese (O.R.=5.2, 2019. Differences in average age at surgery, Body Mass Index, p=0.03), 8 had type II diabetes (O.R.=8.2, p=0.01), 4 were female to male ratio, and presence of at least one osteotomy were smokers (O.R.=2.4, p=0.4), 8 had prior spine surgeries (O.R.=8.3, not significant in both groups (p>0.05). The vancomycin cohort p=0.01), and 12 had prior abdominal surgeries (O.R.=3.9, p=0.06). had 1,252 (65.3%) patients with six (0.48%) diagnosed surgical Eighty-four (30.9%) patients had ASD, of whom 64 were obese site infections, compared to 665 (34.7%) patients with five (0.75%) (O.R.=7.1, p<0.01), 24 had type II diabetes (O.R.=2.5, p=0.06), surgical site infections in the non-vancomycin cohort (p=0.451). 38 were smokers (O.R.=5.7, p<0.01), 20 had prior spine surgeries Four (66.7%) gram-negative bacteria were isolated in the (O.R.=4.6, p<0.01), 36 had prior abdominal surgeries (O.R.=2.5, vancomycin cohort and one (20%) in the non-vancomycin cohort. p=0.02). CONCLUSIONS: The prophylactic use of local vancomycin did not CONCLUSIONS: This study indicates significant risk factors for demonstrate significantly decreased rates of surgical site infections the following complications: hardware failure (smoking, prior in adolescent idiopathic scoliosis patients undergoing primary abdominal surgeries), pseudarthrosis (obesity, type II diabetes, posterior spinal fusion (0.48% versus 0.75%). Further studies are prior spine surgeries), and ASD (obesity, prior spine surgeries, required to elucidate the effectiveness of the use of vancomycin in prior abdominal surgeries). Future studies are needed to further this population. understand the implications of certain modifiable risk factors FDA DEVICE/DRUG STATUS: This abstract does not discuss or (smoking cessation, weight management, diabetic control) and include any applicable devices or drugs. exploring other potential risk factors (i.e bone metabolic diseases, sagittal alignment, number of fused segments, etc.). FDA DEVICE/DRUG STATUS: This abstract does not discuss or 19. Frailty is a better predictor than age of mortality include any applicable devices or drugs. and perioperative complications after surgery for Degenerative Cervical Myelopathy: An analysis of 41,369 patients from the NSQIP database 2010-2018 18. Prophylactic use of local vancomycin does not 1 decrease acute surgical site infection in adolescent Jamie R. Wilson, MD, FRCS, MSc ; Jefferson Wilson, MD, PhD, FRCSC2; Michael G. Fehlings, MD, PhD, FRCSC3 idiopathic scoliosis 1Dept. of Neurosurgery, University of Nebraska Medical Center, Stephen Stephan, MD1; De-An Zhang, MD3; Marilan Luong, MPH2; Omaha, NE, US; 2St. Michael's Hospital, University of Toronto, Robert Cho, MD3; Selina Poon, MD3 Toronto, Canada; 3Toronto Western Hospital, Toronto, ON, Canada 1Los Angeles, CA, US; 2Pasadena, CA, US; 3Shriners for Children BACKGROUND CONTEXT: The effect of frailty on the perioperative Medical Center, Pasadena, CA, US outcomes for patients undergoing surgery for degenerative cervical BACKGROUND CONTEXT: Perioperative surgical site infections for myelopathy (DCM) patients is poorly understood. adolescent idiopathic scoliosis after posterior spinal fusion range Proceedings 35

PURPOSE: The objective of the current study was to model the PATIENT SAMPLE: Patients enrolled to the CSM-International and effect of various models of frailty on the perioperative outcomes for CSM-North America multi-center, prospective cohort studies. surgical DCM patients. OUTCOME MEASURES: Functional outcome (modified japanese STUDY DESIGN/SETTING: Retrospective cohort study. orthopedic association score; MJOA), Quality of Life Outcomes (SF- PATIENT SAMPLE: Patients undergoing surgery for DCM 36 mental component and physical component scores; MCS, PCS) registered in the National Safety and Quality Improvement at 2 years after surgery. Database (NSQIP). METHODS: Patients enrolled into the CSM-NA/CSM-I studies with OUTCOME MEASURES: Mortality, Adverse Events, Readmission, functional and quality of life assessments at baseline and 2 years Reoperation, Length of Hospital Stay and Discharge to non-home after surgery were included. The modified frailty index 5-point destination. score (MFI-5) was calculated for all patients. “Pre-Frail”, “Frail” and METHODS: The modified frailty index 11- and 5-point (MFI-11, “Severely Frail” were compared to “Not Frail” patients on univariate MFI-5), modified Charlson Co-morbidity index (mCCI) and ASA analysis for all outcome measures, and the odds of achieving the grade were calculated for patients with a diagnosis of DCM from minimum clinical important difference (MCID) for each. the NSQIP database 2010-2018. The MFI-11 and MFI-5 scores RESULTS: 757 patients were included, with a mean age of 56[55- were stratified into “Not Frail”, “Pre-Frail”, “Frail” and “Severely 57] years (37% female). Increasing frailty was associated with Frail”. Univariate analysis was performed to assess the risk of increasing age (p<0.001), worse baseline MJOA score (p<0.001) mortality and adverse events by index. Multivariable modelling and worse baseline PCS and MCS scores (p<0.001, p=0.001). of age and frailty with a base model (type of surgical approach, Frailty did not affect the mean difference of MJOA scores after 2 number of operated levels and gender) was performed, with years (2.43[2.15-2.71] vs 2.6[2.04-3.16]; p=0.605) or the change receiver operating characteristic area under the curve analysis in PCS/MCS scores (p=0.899, p=0.138). The odds of achieving (AUC) to define discriminative ability of each measure. MCID for the MJOA is significantly reduced with increasing frailty RESULTS: 41,369 patients were included. Increasing frailty (OR=3.1[2.4-3.9], p<0.001 for “Not Frail” vs OR=1.1[0.8-1.6]; correlated significantly with increased risk of mortality, adverse p=0.5 for “Frail/Severely Frail” patients), but frailty did not affect events, longer hospital stay and risk of non-home discharge the odds of achieving MCID for PCS/MCS. destination. Comparing age and the other indices, the MFI-5 had CONCLUSIONS: Increasing frailty is associated with worse the largest effect size for all variables (odds ratio 8.37 [Frail] - 27.70 baseline functional and quality of life impairment for DCM patients, [Severely Frail]). MFI-5 and mCCI have the best discriminative but this does not affect the mean difference in MJOA or PCS/MCS ability at predicting adverse events with multivariable modelling, scores after 2 years. Frailty has a significant effect on the odds of but the base model with MFI-5 and age had the best predictive achieving the MCID for functional outcomes, but not quality of life value (AUC=0.84). The effect size of frailty was greater than age outcomes. alone for all outcomes, and MFI-5 had a categorical assessment FDA DEVICE/DRUG STATUS: This abstract does not discuss or correlation with MFI-11 of 0.988 (p<0.001). include any applicable devices or drugs. CONCLUSIONS: Frailty has a larger effect size and better discriminative value compared to age alone to predict adverse events after surgery for DCM. A multivariable regression model Tuesday, July 6 using MFI-5 produced the most robust predictive tool, which 2:00–3:00 p.m. substantiates the use of the MFI-5 in preference to the MFI-11 in Cervical Spine clinical practice. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. 21. Role of high sensitive C-reactive protein as a prognostic marker in determining functional outcome after interlaminar epidural steroid injection 20. Increasing frailty is negatively correlated with in cervical radiculopathy long term functional outcomes after surgery for Vijay G. Goni, MB, MD, PhD degenerative cervical myelopathy; 757 patients from Pgimer, Chanfigarh, Chandigarh, India the CSM-NA and CSM-I multicenter observational studies BACKGROUND CONTEXT: Inflammatory cytokines like IL-6, TNF- , etc. produced at the site of disc herniation are considered 1 α Jamie R. Wilson, MD, FRCS, MSc ; Jefferson Wilson, MD, PhD, as pain generators in patients with cervical radiculopathy. Whether 2 3 FRCSC ; Alexander R. Vaccaro, MD, PhD ; Michael G. Fehlings, MD, high sensitive C-reactive protein (hs-CRP) assay can be used for 4 PhD, FRCSC predicting the quantum of inflammation around nerve roots is a 1Dept of Neurosurgery, University of Nebraska Medical Center, matter of investigation. Omaha, NE, US; 2St. Michael's Hospital, University of Toronto, PURPOSE: This study aimed to evaluate the association of hs-CRP Toronto, Canada; 3Rothman Institute, Philadelphia, PA, US; 4Toronto level and functional outcomes measured by Neck Disability Index Western Hospital, Toronto, ON, Canada (NDI) before and after epidural steroid injection (ESI) in patients BACKGROUND CONTEXT: The effect of frailty on the long-term with cervical radiculopathy. outcomes after surgery for degenerative cervical myelopathy STUDY DESIGN/SETTING: Prospective cohort study. (DCM) patients has not been reported. PATIENT SAMPLE: 45 cases with cervical rediculopathy refractory PURPOSE: The objective of the current study was to define the to analgesics and physiotherapy.41 participants in control group effect of frailty on the long term functional and quality of life for measuring baseline hs-CRP. outcomes on surgical DCM patients. OUTCOME MEASURES: Neck disability index (NDI) scores were STUDY DESIGN/SETTING: Retrospective analysis of prospectively used before and after single cervical ESI and compared with hs- collected observational data. CRP levels. Proceedings 36

METHODS: Baseline hs-CRP levels were measured for both fixation features were tested: 1. Traditional single central keel patients in study and control group. Study group patients received (SCK), 2. Low profile teeth (LPT) with domed endplate shape to a single cervical ESI using interlaminar approach and were allow a better fit in case of concave vertebral endplate, 3. Tripod subjected to detailed pre- and post-procedure evaluation using NDI keel (TK), and 4. Small single keel (SSK). A minimum sample size of scores. For them, hs-CRP levels were measured at one, two and 6 implants per prosthesis type were used. Three additional TK disc three months after injection. prostheses and two additional LPT disc prostheses were implanted. RESULTS: Out of 45 patients, 33 had acute and 12 had chronic Three additional Nova disc prostheses and two additional Vivo disc radicular pain. 21 patients with acute pain had significant prostheses were implanted. Specimens were cyclically tested to improvement while 12 had insignificant response to ESI. None of an end limit of 1.5Nm in flexion or extension coupled with 1.5Nm the chronic cases had a significant response. The mean baseline of right and left axial rotation resulting in a total applied moment of hs-CRP (in mg/L) among study group (12±8.281) was significantly 2.25Nm. higher than controls (2.42±1.88). The mean baseline hs-CRP RESULTS: No statistical difference was found between the among acute cases where post ESI NDI score at 3 months had combined (flexion plus extension) sagittal plane range of motion significant reduction, was 12.71±7.008 and those with insignificant or the combined (left plus right) axial motion. All but one of the reduction was 5.592±3.879. specimen migration values were below 0.3mm. Upper prosthesis CONCLUSIONS: Baseline hs-CRP levels can be used to component migration ranged between 0.02mm and 0.08mm and prognosticate the outcome following cervical ESI in patients with between 0.01mm and 0.04mm for the lower components. No acute cervical radicular pain refractory to physiotherapy and significant differences occurred between the upper components or analgesics. the lower prosthesis components of any implant type. FDA DEVICE/DRUG STATUS: This abstract does not discuss or CONCLUSIONS: Three low profile endplate fixation designs for a include any applicable devices or drugs. cervical disc prosthesis which are currently in the investigational phase of FDA clearance were found to provide comparable immediate holding strength to an existing clinically used and FDA 22. Fixation stability of four different cervical disc approved central-based keel design. prostheses endplate fixation configurations FDA DEVICE/DRUG STATUS: Prodisc C (Approved for this indication), Prodisc C Vivo (Investigational/Not approved), Denis J. DiAngelo, PhD1; Daniel Hoyer, MS2; Chloe Chung, MS3; Prodisc C Nova (Investigational/Not approved), Prodisc C SK Tyler Carson, DO4; Kevin T. Foley, MD, FACS5 (Investigational/Not approved) 1The University of Tennessee Health Science Center, Memphis, TN, 2 3 4 US; Medtronic, Memphis, TN, US; Memphis, TN, US; Semmes- 23. Clinical features of extension teardrop fractures Murphey Clinic, Santa Clarita, CA, US; 5Semmes-Murphey Clinic, Memphis, TN, US of the axis: Review of 19 cases Masahiko Watanabe, MD, PhD BACKGROUND CONTEXT: Motion preservation devices have become increasingly popular in the treatment of spinal pathologies Tokai University School of Medicine, Isehara, Kanagawa, Japan that require biomechanical support following removal of the BACKGROUND CONTEXT: Extension teardrop fracture (ETF) degenerated tissue. As these devices continue to be developed of the axis is an extremely rare injury in which the anteroinferior to treat multiple adjacent diseased spinal levels, like the use of corner of the vertebral body is avulsed by the intact anterior multiple disc prostheses or placement of a disc prosthesis adjacent longitudinal ligament due to forced hyperextension of the neck. to a fused level, in depth biomechanical data that supports these This fracture has classically been described as occurring mainly in established surgical methods are needed. elderly osteoporotic patients with minimal or no prevertebral soft- PURPOSE: To assess immediate stability of four cervical disc tissue swelling and no associated neurological deficit. However, prostheses under low endurance multidirectional cyclic loading recent case studies indicate notable exceptions to these classical conditions in a cadaveric cervical spine model. clinical features and few studies have investigated osteoporosis in STUDY DESIGN/SETTING: Each prosthesis was implanted in a fracture patients. cervical functional spinal unit (FSU) and cyclically loaded 2000 PURPOSE: The purpose of this study was to clarify the clinical times under physiological ranges of combined flexion/extension features of ETF of the axis. coupled with axial rotation at a rate of 2.5deg/s. STUDY DESIGN/SETTING: Case series. PATIENT SAMPLE: 16 (C4-C5) and 16 (C6-C7) FSUs were PATIENT SAMPLE: 19 patients with ETF of aixs were treated at our dissected from eight male and eight female cadaveric cervical institution from 1998 to 2019. spines with an average age of 55.9 +/- 9.7 years. Three FSUs were OUTCOME MEASURES: injury etiology neurological deficit not usable due to poor tissue quality which reduced the sample treatment outcome imaging findings size to 29 FSUs. METHODS: A review of cervical trauma cases at our institution OUTCOME MEASURES: A one-way repeated measures ANOVA revealed 19 patients with ETFs of the axis, which constituted 12.0% with a Student Newman-Keuls test was used to compare of upper cervical spinal injuries. The injury etiology, neurological differences in the combined motion data. Anteroposterior endplate deficit, treatment, outcome, as well as imaging findings (size and migration of both the upper and lower implant components was displacement of the fragment, along with the presence/absence measured after 20, 250, 500, 1000, 1500, and 2000 cycles. Tests of C2/3 subluxation, disc injury, and osteoporosis of the axis) were were stopped if implant component migration exceeded 3mm or retrospectively reviewed. endplate fracture was observed, and migrations less than 0.3mm RESULTS: The mean age of the patients was 54.0 years and were defined as clinically stable. distinct osteoporosis of the axis was identified in only one patient. METHODS: Four cervical disc prostheses that had a similar ball Ten patients sustained ETF of the axis in traffic accidents (of which and socket type articulation mechanism but varying endplate one patient died from brain injury), six patients from falls from Proceedings 37

greater than standing height, and three patients from falls from SD 2.4 mm with the wide laminectomy. Laminectomy width was standing height. In two patients there was significant displacement consistent performed for the narrow group with a mean of 15 mm of the fragment which resulted in C2/3 subluxation, but fragment ±1 mm and a mean of 22 mm ±1 mm in the wide group across size did not appear to have any clinical effect and MRI showed C3-7. There were no statistically significant differences between no disc injuries. Two patients presented with minor neurological neutral position, medium lordotic block, and large lordotic blocking deficits classified as Frankel grade D, with the remaining patients with posterior cord drift or protrusion. showing no neurological symptoms. Only one patient required CONCLUSIONS: Posterior cervical laminectomy width, cord drift, surgery for dysphagia suspected to arise from the avulsed and protrusion may not play as large of a role in post-operative fragment. The other patients were treated conservatively with a C5 nerve palsy as previously thought as no statistically significant halo vest or an orthosis. All patients achieved bony fusion, but one difference was found between the 15 mm and 22 mm laminectomy patient with traumatic spondylolisthesis complained of residual width treatment groups in an in vitro cadaveric model when looking neck pain. at changes in cord drift or protrusion. Sagittal plane alignment also CONCLUSIONS: The cases included in this study do not suggest did not significantly change cord drift or protrusion in this cadaveric that osteopenia and older age are risk factors for ETF of the axis. model. This fracture can generally be treated conservatively, with surgical FDA DEVICE/DRUG STATUS: This abstract does not discuss or intervention only for specific cases. The fact that no differences include any applicable devices or drugs. were observed between the outcomes of the patients treated with halo vest and cervical orthosis suggest that most patients can be treated through orthosis immobilization. 25. The features of sagittal alignment among FDA DEVICE/DRUG STATUS: This abstract does not discuss or patients with occipitocervical fusion: How much of include any applicable devices or drugs. a difference does the existing surgery make in their curvature? 24. Effect of laminectomy width and sagittal Ce Zhu, PhD; Xi Yang, MD; Limin Liu, MD; Yueming Song, MD alignment on spinal cord drift Department of Orthopedics and Orthopedic Research Institute, Addison R. Wood, DO, PhD1; William Pipkin, MD2; Varun West China Hospital, Sichuan University, Chengdu, China Sambhariya, MD3 BACKGROUND CONTEXT: Previous studies have explored the 1John Peter Smith Hospital, Fort Worth, TX, US; 2JPS Health interrelationship between the upper and lower cervical sagittal Network, Fort Worth, TX, US; 3John Peter Smith, Frisco, TX, US alignment. However, there are limited studies regarding the sequential change of cervical sagittal alignment of the upper BACKGROUND CONTEXT: Postoperative C5 nerve palsy is a and lower cervical spine after occipitocervical fusion (OCF) and possible complication of cervical laminectomy with an incidence its relationship with postoperative dysphasia. In addition, to our reported as high as 10.6%. There are multiple theories as to the knowledge, no comparison of the cervical sagittal alignment of mechanism for this nerve palsy, but there is little agreement in patients with craniocervical junction disorders with that of the the literature on the definitive cause. There is some evidence normal populations has been reported. suggesting posterior cord drift, sagittal alignment, and PURPOSE: To compare the cervical sagittal alignment in laminectomy width are related to the incidence of C5 palsy through patients with craniocervical disorders with that of a normal postoperative imaging studies, but these have a small sample size control population and to investigate the sequential change and and are not controlled comparisons. interrelationship of sagittal alignment of the upper and lower PURPOSE: To determine the effect of sagittal alignment and cervical spine after OCF and its relationship with postoperative posterior cervical laminectomy width on spinal cord drift. dysphasia. STUDY DESIGN/SETTING: In Vitro Cadaveric. STUDY DESIGN/SETTING: A retrospective study. PATIENT SAMPLE: 6 fresh frozen cadavers. PATIENT SAMPLE: 84 patients who underwent OCF (OCF group) OUTCOME MEASURES: Posterior cord drift, thecal sac protrusion, and 42 asymptomatic volunteers matched with age and sex laminectomy width, cobb angle. (Control group). METHODS: Six fresh frozen cadavers were scanned using 3D OUTCOME MEASURES: Occipital to C2 angle (O-C2a), occipital fluoroscopy after replacement of CSF with contrast dye prior and external acoustic meatus to axis angle (O-EAa), C2 tilting to performing laminectomies at C3-C7. The cervical spine was angle (C2Ta), C2–7 angle (C2-7a), T1 slope, C2-7 sagittal vertical scanned at each interval in the experiment in while neutral position, axis (C2-7 SVA), pharyngeal inlet angle (PIA), and the morbidity of 1.5 inch shoulder block, and 3 inch shoulder block in place to dysphagia after OCF. increase cervical lordosis. A narrow 15 mm laminectomy was first METHODS: Patients in the OCF group were divided into dysphagia performed and then a wide 22 mm laminectomy followed from and non-dysphagia subgroup according to whether they had C3-C7 both with interval scanning and positioning changes. The suffered postoperative dysphagia. O-C2a, O-EAa, C2Ta, C2-7a, posterior cord drift, laminectomy width, and thecal sac protrusion T1 slope, C2-7SVA, and PIA were measured and compared at were all measured at neutral position, medium lordosis, and large baseline, 1‑month and last follow‑up after OCF surgery among lordosis positions for the native cervical spine, narrow laminectomy, different groups. Simple linear regression was used to measure and wide laminectomy groups. the correlations between the parameters and the presence RESULTS: Posterior spinal cord drift and protrusion from C3-7 of postoperative dysphagia, and the correlations within the (as measured at each level) all showed a positive linear trend with parameters. increasing laminectomy width. The posterior cord drift at C5 was RESULTS: The O-C2a and PIA of patients in OCF group were 4.1 mm SD 1.0 mm with the narrow laminectomy and 5.0 mm SD significantly smaller than that of patients in Control group (P < 1.9 mm with the wide laminectomy. The spinal protrusion at C5 0.05), while the O-EAa, C2Ta and C2-7a of OCF patients were was 3.6 mm SD 2.5 mm with the narrow laminectomy and 7.6 mm significantly greater than that of normal controls (P < 0.05). In the Proceedings 38

OCF group, there was no statistical difference in O-C2a, C2-7a and 1 month of treatment. The cause of onset was attributed to any PIA at baseline, 1 month and at final follow-up after surgery (P > unknown cause in four patients, minor trauma in one patient, and 0.05). After the OCF surgery, there were 20 patients with dysphagia treatment of inflammatory disease in six patients. Among these and 64 patients without dysphagia. The O-C2a and PIA decreased patients, four (3.1%) patients required over 2 months of treatment. significantly in patients with dysphagia 1 month after surgery, One boy could not be treated using Glisson's traction; as a result, and the effect remained at the final follow-up, while the C2-7a he needed remodeling therapy for over 6 months. increased 1 month postoperatively and remained at the last follow- CONCLUSIONS: The use of Glisson's traction was successful, with up. Yet the O-C2a, C2-7a and PIA of patients without dysphagia the condition of nearly 100% of patients improving, and 1 of 127 were comparable pre- and postoperatively. Pearson’s correlation cases (0.89%) required remodeling therapy. In addition, 1.5% of test showed that the postoperative O-C2a correlated significantly boys and 3.1% of girls required over 1 month of treatment; thus, with C2-7a and PIA. this indicates that girls are at a higher risk of prolonged healing CONCLUSIONS: Compared to normal age-matched control compared with boys. Moreover, this study did not include patients population, patients with craniocervical junction disorders had with Fielding classifications 3 and 4. Thus, further examination is a more kyphotic upper cervical sagittal alignment and a more required for such cases. lordotic lower cervical sagittal alignment. The effectiveness of FDA DEVICE/DRUG STATUS: This abstract does not discuss or the restoration of cervical sagittal alignment provided by OCF include any applicable devices or drugs. surgery could be limited with the neglect of realignment of the craniocervical junction. The reduction of the O-C2a after OCF surgery would increase the C2-7a and decrease the PIA and lead to 27. Characteristic features of cervical spine postoperative dysphasia. deformity in Dropped Head Syndrome FDA DEVICE/DRUG STATUS: This abstract does not discuss or 1 2 include any applicable devices or drugs. Yoshifumi Kudo, MD, PhD ; Ichiro Okano, MD ; Koji Ishikawa, MD, PhD3; Akira Matsuoka, MD1; Hiroshi Maruyama, PhD, MD4; Ryo Yamamura, PhD5; Yusuke Oshita, MD, PhD6; Yushi Hoshino, MD, PhD7; Katsunori Inagaki, MD, PhD8; Tomoaki Toyone, MD, PhD4 26. Characteristics of prolonged healing in atlantoaxial rotatory fixation treatment 1Showa University Hospital, Shinagawa-ku, Tokyo, Japan; 2Hospital for Special Surgery, New York, NY, US; 31-5-8 Hatanodai 1 1 Yusuke Oshita, MD, PhD ; Haruka Emori, MD, PhD ; Koji Ishikawa, Shinagawa-ku, Tokyo, Japan; 4Showa University, Tokyo, Japan; 2 4 4 MD, PhD ; Akira Matsuoka, MD ; Hiroshi Maruyama, PhD, MD ; 5Tokyo, Shinagawa, Japan; 6Showa Univ. Northern Yokohama 3 4 Ichiro Okano, MD ; Yoshifumi Kudo, MD, PhD ; Toshiyuki Shirahata, Hosp., Yokohama, Japan; 7Showa University Koto Toyosu Hospital, 5 6 7 MD, PhD ; Yushi Hoshino, MD, PhD ; Koji Kanzaki, MD ; Tomoaki Tokyo, Japan; 8Showa Univ., Shinagawa-ku, Japan Toyone, MD, PhD8 BACKGROUND CONTEXT: Recently, there are several studies 1 Showa University Northern Yokohama Hospital, Yokohama, focused on whole spine sagittal alignment of Dropped Head 2 3 Japan; 1-5-8 Hatanodai Shinagawa-ku, Tokyo, Japan; Hospital Syndrome (DHS). However, few studies have described the details 4 for Special Surgery, New York, NY, US; Showa University about cervical deformity of DHS ever. 5 Hospital, Shinagawa-ku, Tokyo, Japan; Showa University School PURPOSE: The purpose of this study is to investigate the of Medicine, Department of Orthopedics Surgery, Tokyo, Japan; characteristic features of cervical spine deformity in DHS. 6 7 Showa University Koto Toyosu Hospital, Tokyo, Japan; Showa STUDY DESIGN/SETTING: retrospective radiographic study. 8 Univesity Fujigaoka Hospital, Yokohama, Kanagawa, Japan; Showa PATIENT SAMPLE: DHS patients who presented to our hospital University, Tokyo, Tokyo, Japan in 2014-2019 were included in this study. Patients with cervical BACKGROUND CONTEXT: Although a conservative treatment spondylotic myelopathy (CSM) were also included as control. is typically used to manage atlantoaxial rotatory fixation (AARF), METHODS: The following spinal parameters were assessed: C2-7A many cases are resolved in 1 or 2 weeks. However, no study has (C2-4, C5-7), C2-7ROM (Flex and Extension, C2-4, C5-7), C2-7SVA, evaluated the characteristics of prolonged AARF cases. T1S. We also assessed the degree of cervical degeneration using PURPOSE: The aim of the present study was to investigate the cervical degenerative index (CDI: Ofiram E, J Orthopaed Traumatol characteristics of prolonged healing in AARF treatment. 2009). CDI consists of four factors; Disc space narrow (D), Sclerosis STUDY DESIGN/SETTING: Retrospective study. (S), Osteophyte (O), Listhesis (L) with grading 0(normal)~3(most PATIENT SAMPLE: A retrospective analysis of patients with AARF severe spondylotic change). Student T-tests were used to compare treated at our hospital was conducted from April 2011 to March the two groups. The level of significance was set at P<0.05. 2020. One patient with third-party action at the point of injury was RESULTS: Forty one DHS patients (10 male and 31 female, average excluded because the timing of pain disappearance could not be 75.8±8.7 years) and 41 CSM patients (10 male and 31 determined. female, average 75.2±7.6 years) were enrolled in this study. The OUTCOME MEASURES: Data regarding age, gender, Fielding comparison of data of the radiologic parameters were as follows classification, treatment duration, treatment method, and clinical (DHS vs CSM: P value); C2-7A (-35.53±20.94° vs 15.26±13.92°: outcomes were collected. P<0.0001), C2-7ROM (34.34±20.58°vs 42.26±12.47°: P=0.029), METHODS: One-hundred twenty-seven patients [62 boys and C2-7SVA (63.90±15.25°vs 23.34±12.18°: P<0.0001)T1S 65 girls; average age: 5.5 (range: 1-13 years)] were treated in the (38.8±23.37°vs 28.58±9.78°:P=0.013), C2-7F (-43.24±17.39°vs study period. -11.92±16.10° :P<0.0001), C2-7E (-8.90±24.98°vs 30.34±14.42° RESULTS: All cases were Fielding type 1 and 2. Glisson's traction :P<0.0001). In every parameter, there was a statistical was used if torticollis persisted following color fixation in the initial significance between two groups. In more detailed analysis in week. The mean duration to treat was 9 days, and 11 (8.7%) cases DHS cases, there was significant differences in C2-4A vs C5-7A required more than 1 month. These 11 cases include 1 boy and (-11.51±11.68° vs-19.46±11.63° :P<0.0022), C2-4F vs C5-7F 10 girls. Therefore, 1.5% of boys and 15.4% of girls required over (-14.53±10.36° vs-20.14±12.71° :P=0.0273) and C2-4E vs C5- Proceedings 39

7E (-0.658±14.755° vs -8.073±10.72° :P=0.0034). However, PATIENT SAMPLE: Eight hundred fourteen residents (men, there was no significant difference in C2-4ROM vs C5-7ROM 246; women, 568, mean 63.6 y) with an age range of 21–97 y in (13.68±8.98° vs 13.48±10.85° :P=0.9126). In assessment of seacoast regions at western part of Japan. CDI, more degenerative changes were seen in lower levels in both OUTCOME MEASURES: Endplate changes observed by MRI were groups. In comparison between DHS and CSM, the scores of Disc classified using the Modic classification system of types I, I/II, II, space narrowing at C3/4/5/6/7, Sclerosis at C5/6/7, Osteophyte at II/III, and III. LBP was defined as current, continuous back pain C4/5/6/7 and Listhesis at C2/3/4/5 of DHS group were significantly lasting 48 hours or more in the past month. higher than these of CSM. This means that massive degenerative METHODS: We assessed the prevalence of the Modic types at changes in lower cervical level and slippage in middle cervical level each lumbar disc level. Analysis of variance was used to assess were more obvious in DHS group compared to CSM group. the association between the LBP Visual Analog Scale (VAS) score CONCLUSIONS: These results suggest that dropped head and Modic types I, I/II, II, II/III, III, and those with no Modic changes. deformity is not a simple kyphosis, but is a complexed deformity Multivariate logistic regression models were used in the following including severe degeneration with irreversible kyphosis at lower manner: to evaluate the association between each Modic type and level (C5-7) and reducible listhesis at upper and middle level (C2- the presence of LBP; to compare the associations between the 4). It is not certain that these characteristic features are cause or types to those without Modic change; and to adjust for age, sex, consequence of this deformity, however, we believe that these are body mass index, and the presence of disc degeneration and high deeply involved with this pathology. Surgeons should take these intensity zones as previously defined. Additionally, we performed a characteristic features into account in corrective surgery. multivariate logistic regression analysis of the association between FDA DEVICE/DRUG STATUS: This abstract does not discuss or Modic types I and I/II. include any applicable devices or drugs. RESULTS: Modic changes anywhere in the lumbar spine were noted in 63.5% (n = 516) of all participants, within which the prevalence of Modic types I, I/II, II, II/III, and III was 7.7% (n = 63), Tuesday, July 6 10.8% (n= 88), 40.0% (n = 326), 2.1 % (n = 17), and 2.7 % (n = 22), respectively. The LBP VAS score was 18.4±22.6, 28.0±28.2, 5:00–6:00 p.m. 12.3±21.2, 19.2±23.8, 19.2±23.8, and 13.3±24.0 in participants New Concepts in Imaging with type I, type I/II, type II, type II/III, and type III, and no Modic changes, respectively. Furthermore, the LBP VAS score was 28. Extensive subphenotyping of lumbar modic significantly higher in patients with type I/II than in those with type changes and their association with low back pain in a I (p<0.05). Associations were found between Modic types I and I/ large population-based cohort: The Wakayama Spine II and the presence of LBP (odds ratio [OR]: 2.46; 95% confidence Study interval [CI]: 1.60-3.81). Furthermore, Modic type I/II was more significantly associated with LBP than was Modic type I (OR: 1.99; Masatoshi Teraguchi, MD, PhD1; Hiroshi Hashizume, MD, PhD2; 95% CI: 1.02 - 3.91). Hidenobu Tamai, MD3; Hiroyuki Oka, MD4; Dino Samartzis, ScD, CONCLUSIONS: Type I/II Modic changes were significantly PhD, MSc5; Noriko Yoshimura, MD, PhD4; Hiroshi Yamada, MD, associated with LBP with a stronger pain intensity than type I. To PhD6 our knowledge, this is the first large population-based study on 1Spine Care Center, Wakayama Medical University Kihoku Hospital, the association between extensive Modic changes types and LBP. Ito-gun, Wakayama, Japan; 2Wakayama, Japan; 3Wakayama Our study substantiates that Modic changes overall are clinically Medical University, Wakayama, Wakayama, Japan; 4Tokyo, Japan; relevant phenotypes, but subphenotype analyses revealed specific 5Queen Mary Hospital, Hong Kong, Hong Kong; 6Wakayama patterns with LBP that need to be taken into account for any future Medical University, Dept of Orthopaedic Surgery, Wakayama, Japan study addressing Modic changes as well as to address mechanisms BACKGROUND CONTEXT: Magnetic resonance imaging (MRI) related to pain generation. of the lumbar spine is a useful tool used to identify the potential FDA DEVICE/DRUG STATUS: This abstract does not discuss or source of LBP and help guide management. However, there is include any applicable devices or drugs. often a discrepancy between the clinical profile and the MRI findings. The Modic classification was introduced in 1988. When different types, usually I and II or II and III, are observed at the same 29. Facet joint opening on CT is a predictor for poor adjacent vertebral body, they are termed mixed types (I/II or II/III, clinical outcomes after less invasive decompression respectively). However, several previous studies considered that surgery for lumbar spinal stenosis type I Modic change represents an active inflammatory process; Kentaro Yamada, MD1; Hiromitsu Toyoda, MD, PhD2; Koji Tamai, therefore, they classified type I and type I/II as ‘‘type I’’ group MD2; Shinji Takahashi, MD2; Akinobu Suzuki, MD, PhD2; Masatoshi in previous analyses. Similarly, previous studies had classified Hoshino, MD3; Hidetomi Terai, MD, PhD3; Hiroaki Nakamura, MD, type II and type II/III as ‘‘type II’’ and type “III”. To the best of PhD1 our knowledge, no population-based study has examined the association of ’type I’,’ type I/II’, ’type II’,’ type II/III’, and ’type III’ with 1Osaka City University Graduate School of Medicine, Osaka City, the presence and intensity of LBP. Japan; 2Osaka City University, Osaka, Japan; 3Dept. of Orthopaedic PURPOSE: The purpose of this study was to examine the Surgery, Osaka City University, Graduate School of Medicine, prevalence of the 5 types of Modic change throughout the lumbar Osaka, Japan region and to clarify the associations between LBP presence and BACKGROUND CONTEXT: We have performed less-invasive intensity and each type of Modic change in a large population. surgery using microscopy or microendscopy for lumbar spinal STUDY DESIGN/SETTING: Descriptive and cross-sectional study stenosis without severe segmental spinal instability by dynamic using a population-based cohort X-ray. Although spinal fusion surgery is gold standard surgical treatment for case with segmental spinal instability, it has not Proceedings 40

been clarified what is threshold which can be treated by less- 30. Machine vision image guided system in spinal invasive decompression alone surgery. Facet joint opening on CT fusion surgery: Early clinical experience was reported as an indicator for segmental spinal instability by an experimental study. However, there is no study which investigated Harsh Wadhwa, BS1; Christopher Leung, BA2; Matthew Sklar, the impact of facet joint opening on clinical outcomes after BS3; Karen Malacon, BA4; Elizabeth Tong, MD1; John Ratliff, MD5; decompression alone surgery. Corinna Zygourakis, MD6 PURPOSE: The purpose of this study was to investigate association 1Stanford, CA, US; 2Stanford University School of Medicine, between facet joint opening and clinical outcomes after less- Department of Neurosurgery, Stanford, CA, US; 3Stanford invasive surgery. University, Palo Alto, CA, US; 4Stanford School of Medicine, STUDY DESIGN/SETTING: Retrospective cohort study. Stanford, CA, US; 5Stanford University School of Medicine / Hospital PATIENT SAMPLE: This study included a total of 296 patients & Clinics, Palo Alto, CA, US; 6Stanford Dept of Neurosurgery, (male 156/ female 140, mean age at surgery 69.1 years, mean Stanford, CA, US follow-up 6.2 years) who underwent less-invasive surgery for BACKGROUND CONTEXT: Computer-assisted navigation lumbar spinal stenosis and have followed up ≥ 5 years in one improves accuracy of pedicle screw placement. The machine institution. vision image guided system (MvIGS), 7D Surgical, was developed OUTCOME MEASURES: Clinical outcomes was evaluated by (1) to streamline surgical workflow and allow intra-operative navigation Reoperation: revision surgeries due to progression of degeneration registration in seconds, without intraoperative radiation. This study either at index lumbar level or not, and (2) improvement ratio of presents the early clinical outcomes of spinal fusion with MvIGS. Japanese Orthopaedic Association (JOA) score, and achievement PURPOSE: To identify outcomes of spinal fusion with intraoperative of minimal clinically important difference (MCID) of visual analogue MvIGS use. scale for low back pain or leg pain at 5 years: MCID of low back pain STUDY DESIGN/SETTING: Retrospective case series. 21, MCID of leg pain 28. PATIENT SAMPLE: Adult patients who underwent spinal fusion METHODS: Facet opening was defined as ≥ 2mm facet interval with MvIGS at a single institution. on axial images of CT in each lumbar level. Facet joint opening OUTCOME MEASURES: Primary outcome was postoperative was evaluated at index decompression level (d-FJO) and ≥3 complication. Secondary outcomes included readmissions, levels of facet opening within lumbar segment from L1-2 to L5-S reoperations, and radiation exposure. (m-FJO). Clinical outcomes were compared between patients with METHODS: Spinal fusion cases in adult patients (n=50) with and without d-FJO or m-FJO, coupling with factors of patients’ intraoperative MvIGS at a single institution with three attending demographic, preoperative symptom severity, and radiological surgeons were reviewed. Baseline demographics, comorbidities, # findings (plain X-ray and MRI). fused levels, surgical indications, operative time, estimated blood RESULTS: There were 129 patients (44%) with d-FJO, and 61 loss (EBL), perioperative and 30-day complications, unplanned patients (21%) with m-FJO. Preoperative d-FJO was more common readmissions, and reoperations were collected. Preoperative, in cases with lateral olisthesis (24% vs. 11%, p<0.01) and m-FJO intraoperative, and postoperative radiation exposure was totaled. was less common in cases with spondylolisthesis of ≥6 mm (6% RESULTS: Across 50 patients, mean age was 61±17 years, vs. 18%, p=0.02). Reoperation was performed in 29 cases (10%): and 44% were female. Mean ASA and CCI were 2.86±0.57 revision at index decompression level 17cases, and revision at and 2.82±2.15, respectively. 24% had BMI >30, 6% actively other lumbar level 14case. Reoperations were more common in used tobacco, and 22% were diabetic. Indication for surgery patients with d-FJO (15% vs. 5%). Cox Proportional hazard analysis included degenerative disease (33/50), deformity (1/50), tumor indicated d-FJO were predictor for revision at index decompression (5/50), infection (2/50), and trauma (9/50). Mean fusion length level (hazard ratio [HR] 4.04, p=0.03), and m-FJO for revision at was 5.5±2.2 levels, and 12% (6/50) were revision cases. Mean other lumbar levels (HR 3.71, p=0.03). In addition, patients with operative time was 285±128 minutes and EBL was 544±601 m-FJO showed a slightly poorer improvement of JOA score (74% vs. mL. Most patients were discharged home (46%) or to skilled 80%, p=0.03) and a lower rate of achieving MCID for low back pain nursing facility (22%) or rehabilitation (24%). There were 7 (14%) (34% vs. 52%, p=0.03). complications, 4 (8%) readmissions and 2 (4%) reoperations. One CONCLUSIONS: This study indicated that facet joint openings, reoperation was for a wound dehiscence, while the other was for not only that at index level but also multi-level facet joint opening, lateral pedicle screw placement. Median total patient radiation were predictor for poor outcomes. Facet joint opening at index exposure was 1433.5±2836.4 mGy cm2. Median registration time decompression level is useful as a predictor of reoperation at index was 83±21s. surgery due to increased instability, while multi-level facet joint CONCLUSIONS: MvIGS is a safe and effective method of opening is useful as a predictor of reoperation at other lumbar intraoperative navigation for spinal fusion surgery. The optical levels due to progression of degeneration. topographic imaging technology allows rapid registration and can FDA DEVICE/DRUG STATUS: This abstract does not discuss or be used for a variety of indications. include any applicable devices or drugs. FDA DEVICE/DRUG STATUS: 7D Surgical System (Approved for this indication) Proceedings 41

31. Novel magnetic resonance imaging techniques CONCLUSIONS: QSI has the possibility to be a novel biomarker of IVD degeneration from basic to clinical. for assessing intervertebral disc degeneration and FDA DEVICE/DRUG STATUS: This abstract does not discuss or regeneration include any applicable devices or drugs. Daisuke Nakashima, MD, PhD Keio University School of Medicine, Department of Orthopaedic Surgery, Tokyo, Japan 32. An analysis for safety insertion of sacral alar iliac BACKGROUND CONTEXT: The grading of intervertebral disc (IVD) screw on the fluoroscopy, using three-dimensional degeneration has been evaluated with Pfirrmann classification analyzing software on T2-weighted MRI imaging (T2WI). However, it is still difficult Kentaro Yamada, MD1; Yuichiro Abe, MD, PhD2; Hiroaki Nakamura, to classify subtle changes of degeneration using this method, MD, PhD1 which is qualitative and based on morphological changes over 1Osaka City University Graduate School of Medicine, Osaka City, the progression of degeneration. For this reason, a quantitative Japan; 2Eniwa Hospital, Eniwa, Japan and more sensitive classification system has been sought. Q-space imaging (QSI) is a quantitative diffusion-weighted MRI BACKGROUND CONTEXT: S2 alar-iliac (SAI) screws have been procedure that makes it possible to detect delicate changes in the common anchor recently in cases of lumbosacral fixation. The microstructure of environments in which free water movement is screw deviation to anterior or caudal direction has potential risk restricted. We have previously verified the efficacy of antioxidant for major vessel injury, internal iliac artery or superior gluteal N-acetyl cysteine (NAC) on rat IVD degeneration using a semi- artery. Therefore, use of navigation system or intraoperative CT quantitative molecular technique. is recommended to avoid such injuries. On the fluoroscopy, the PURPOSE: The purpose of this study is to investigate the possibility tear-drop-view has been recommended to confirm adequate screw of QSI for rat and human IVD. insertion. The flaw of tear-drop-view is difficult to set the screws STUDY DESIGN/SETTING: Animal study / Single-center, and review the fluoroscopy simultaneously due to the setting retrospective clinical study. of the fluoroscopy unless special surgical table. The pelvic inlet PATIENT SAMPLE: 45 adult volunteers. view is another recommended methods, however, no study have METHODS: Animal study: A rat degenerative model was investigated how the beam should be tilted. generated in which the IVD was punctured using a needle on the PURPOSE: to investigate the condition of the fluoroscopy which coccygeal vertebral levels. NAC (1000mg/mL) was given orally to could provide accurate information of SAI screw deviation under degenerative model rats 1 week before puncture. We designated anteroposterior or lateral view using three-dimensional analyzing rats without IVD puncture as the control group, punctured rats software. without oral administration of NAC as the puncture group, and rats STUDY DESIGN/SETTING: CT image analyzing study for safety on punctured with NAC as the NAC group (n=5 in each group). Sagittal thoracolumbar surgery. MRI was performed using a 7T MRI scanner with cryoprobe (Bruker PATIENT SAMPLE: A total of 50 patients who were over 40 years BioSpin, Ettlingen, Germany) :21T equivalent MRI (repetition time old and taken abdominal thin-slice CT in the outpatient clinic of (TR)/echo time (TE), 3500/33.7 ms; Δ/δ, 101.2/3.6 ms; b-value, internal medicine were included in this study. 0–8000 s/mm2; FOV, 54 × 54 mm2; matrix size, 360 × 360; MPG OUTCOME MEASURES: The conditions which provide proper moment, three axes (x, y, and z)). After MRI, histological examination recognition for the screw deviation were investigated on lateral view was performed by Hematoxylin-Eosin staining. Clinical study: 45 and anteroposterior view with beam tilted caudally by comparing adults (26 males, 19 females, mean [SD] age of 62.1 [8.5] years) virtual ideal and deviated screws using the raysum methods in diagnosed with nonspecific low back pain were included. Sagittal order to virtualize fluoroscopic images. MRI was performed using a 3T MRI scanner (Siemens Skyra, METHODS: The obtained CT images were reconstructed using 3D Munich, Germany) (TR/TE, 4000/89 ms; Δ/δ, 63/48.4 ms; b-value, analyzing software for simulation of spinal screws. The ideal SAI 0–4000 s/mm2; FOV, 57.6 × 57.6 cm2; matrix size, 192 × 192; MPG screws (7.0mm *80mm) were individually set on three-dimensional moment, six axes (x, y,z and invert x,y,z )).IVD areas were measured analyzing software from entry point of 1 mm inferior and 1 mm lateral by in-house software. IVD degeneration grading was evaluated by T2 to the S1 dorsal foramen. Anterior or caudal deviated screws were mapping values (T2map) [ms] and QSI in rat and human. Pfirrmann defined as deviated half thread of screw by rotation anteriorly or classification only in human. QSI parameters included probability caudally from the entry point of the ideal screw. at zero displacement (arbitrary unit [a.u.]), kurtosis [a.u.], and full RESULTS: The anterior deviated screws were not recognized on width at half maximum (FWHM) [µm].) This study was approved by lateral view in all cases, but recognized on pelvic inlet view in all institutional review board of Keio University. cases. The anterior deviated screws were recognized in specific RESULTS: Animal study: IVD degeneration by puncture was range of beam tilted angle from S1 slope: 32.8±12.1 –101.8±15.0°. confirmed by histology, T2 mapping, and all QSI parameters (P < If the beam tilt angle set by 60°, all anterior deviated screw, except .001); however, the inhibitory effect of NAC was confirmed only by one case, were recognized. The recognizable beam tilt angle ranges QSI parameters (Kurtosis and ZDP: both P < .001; FWHM: P < .01). for caudal deviated screw were 15.9±12.0 –46.6±11.4°. However, Kurtosis had the largest effect size (Kurtosis: 1.13, ZDP: 1.06, and 21% of screws were not able to be recognized in any inlet angle. FWHM: 1.02) when puncture and NAC groups were compared. QSI CONCLUSIONS: The safety margins of SAI screws were typically has a higher sensitivity than conventional quantitative methods smaller in anterior direction than in caudal direction. Intraoperative for detecting the progressive change and inhibitory effect of NAC fluoroscopic setting was recommended 60° inlet from S1 slope to in IVD degeneration. Clinical study: There was no significant avoid anterior screw deviation in cases which fail to obtain clear difference between T2 map and Pfirrmann grade 3 and 4. On the images by the tear-drop-view. The lateral view was recommended to other hand, we succeeded clearly in distinguishing Pfirrmann 3 and make sure that SAI screw was not deviated caudally. 4 to use kurtosis. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. Proceedings 42

33. Kinematics of the spine and hips following Patients who retained a higher hip ROM independent of fusion level reported higher EQ5D scores, lower ODI and VAS scores. ROM of thoracolumbar fusion correlated to HRQOL scores the hips following surgery should be considered pre-operatively. Luana Leal, BS; Shane Burch, MD FDA DEVICE/DRUG STATUS: This abstract does not discuss or University of California San Francisco, San Francisco, CA, US include any applicable devices or drugs. BACKGROUND CONTEXT: The methodologies used to evaluate spinal deformity in adults have been evolving since the last two centuries, along with the goals of spinal surgical procedures. 34. Prevalence of modic changes in pediatric Normalizing spine function while minimizing pain, and stopping patients with low back pain regression are major outcomes in the surgical field. Surgeons have Hiroaki Manabe, MD1; Toshinori Sakai, MD, PhD1; Masatoshi relied on static full-length standing spine radiographs to measure Morimoto, MD2; Fumitake Tezuka, MD, PhD1; Kazuta Yamashita, SVA and spinopelvic parameters to guide surgical decision making MD3; Takashi Chikawa, MD, PhD4; Koichi Sairyo, MD, PhD1 in regard to length of fusion, however, standing radiographs fail to 1Tokushima University, Tokushima, Japan; 2Kuramoto, Japan; demonstrate the dynamic nature of spinopelvic parameters during 3Tokushima, Japan; 4Tokushima Prefecture Naruto Hospital, normal movement. To date, no large studies have examined the Department of Orthopedic Surgery, Naruto, Tokushima, Japan dynamic changes in spinopelvic parameters in patients with adult spinal deformity before and after surgery. BACKGROUND CONTEXT: Changes in signal intensity around the PURPOSE: The purpose of this study is to demonstrate how lumbar vertebral endplates and subchondral bone on magnetic alterations in dynamic spinopelvic parameters in ASD correlate to resonance imaging (MRI) scans were first identified in 1988 by patient reported outcomes and function after surgery allowing for Modic et al. and are now known as Modic changes (MCs). There further optimization of alignment in stance and during ambulation. have been many reports on MCs in adult patients, including one STUDY DESIGN/SETTING: Retrospective review of prospectively large-scale, population-based, cross-sectional study that found collected kinematic assessment of patients undergoing multilevel an association between endplate defects and these changes. fusion. However, to date, there has been only a few study of MCs in PATIENT SAMPLE: 59 patients (15 male, 44 female) with adult pediatric patients. spinal deformity with mean age of 60.3 and a control group of eight PURPOSE: We investigated the prevalence of Modic changes healthy patients (4 male, 4 female) mean age of 36.9 took part in (MCs) and associated pathologies in pediatric patients. this investigation. METHODS: A total of 368 MRI obtained for 240 male and 128 OUTCOME MEASURES: The primary outcome measure will be female patients under the age of 18 years with complaints of low angular change during flexion after undergoing spine fusion as back/leg pain were retrospectively examined. We investigated calculated using the motion capture system. Secondary outcome conditions of the growth plate by focusing on the L3 anterior measures will be the comparison of kinematic data to VAS, EQ5D corner of the lumbar vertebral on MRI in cases with MCs. The and ODI scores. relationship between MCs and underlying diseases, including METHODS: Kinematic data was obtained using a motion capture lumbar spondylolysis/spondylolisthesis, was assessed. The degree analysis system. Assessment of the thoracolumbar spine and hips of disc degeneration in patients with MCs was evaluated using the were conducted using a standardized marker set for patients who Pfirrmann grading system. had undergone >12 level fusion (n-11), 7-12 level fusion (n=17), RESULTS: MCs were identified in six patients (1.6%). In five of 1-3 level fusion (n=17) and 0 (n=14) levels fusion. Measurements the six patients, the signal intensity changes were localized to the of sagittal spinal alignment and spinopelvic parameters were anterosuperior endplate of the affected vertebra; the MCs were taken during flexion and extension trials in the x, y and z planes at associated with anterior apophyseal ring fracture and an open the following segments: C7-T12, T12-S1, and C7-pelvis. Healthy growth plate in all these cases. Disc degeneration was classified patients were also analyzed, and Kinematic data was compared as Pfirrmann grade I in three patients and gradeⅡand Ⅲ in one across all groups to standardized radiographic parameters and patient each. One patient had type I changes associated with grade ODI, EQ5D and VAS scores. IV disc degeneration and herniation. RESULTS: The maximum mean angular change through the x CONCLUSIONS: The prevalence of MCs in pediatrics patients axis, in C7-Pelvis segment, for 0, 3, 7, and 12 levels fused are was much lower than the rates reported in adults and there were 103.83, 81.06, 86.64, and 68.98 degrees, respectively. The no cases of severe disc degeneration. In children, a fracture cohort group has a max mean of 131.61 degrees. The volunteer of the apophyseal ring is an avulsion fracture that occurs in a group and patients without fusion maintained higher angular mechanically weak growth plate that is in contact with damaged change compared to the fused patients (p≤ 0.05). Correlation subchondral bone and leads to MCs due to destruction of the coefficients are as follows between angular change of the C7-pelvis barrier function as well as inflammation at the injury site. segments and EQ5D (R=.419, p=0.001), ODI (R=.460, p=0.001), FDA DEVICE/DRUG STATUS: This abstract does not discuss or VAS (R=.318, p= 0.015). No statistical differences (p ≤.05) include any applicable devices or drugs. were measured for VAS, ODI and EQ5D scores between patient groups. Radiographic measurements include: PI (57.3), PT (21.8), LL (51.3), PI-LL (5.73). CONCLUSIONS: HRQOL scores in adult deformity patients are not impacted by levels fused or diminished ROM. However, ROM of the thoracolumbar spine is impacted by levels fused. ODI, EQ5D and VAS scores were not different between patient groups but a moderate correlation to ROM of the hip joint in those with and without fusion was identified. The highest angular change was measured in the C7-pelvis segment (hip ROM) across all groups. Proceedings 43

Wednesday, July 7 FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. 2:00–3:00 p.m. Use of New Technology in Spine Care 36. Successful fusion in cervical and lumbar spinal 35. Telemedicine visits generate accurate surgery using unique bioactive glass putty interventional procedure plans in spine patients without in person evaluations George Hanna, MD1; Adam Bruggeman, MD2; Paul J. Slosar, MD3; 4 5 Harry M. Lightsey IV, MD1; Alexander Crawford, MD2; Grace Xiong, Edward H. Chung, MD ; Hyun W. Bae, MD MD1; Brendan Striano, MD2; Andrew J. Schoenfeld, MD3; Andrew 1Cedars-Sinai Medical Center, Los Angeles, CA, US; 2Texas Spine Simpson, MD4 Care Center, San Antonio, TX, US; 3SpineCare Medical Group, Daly 4 1Boston, MA, US; 2Harvard Combined Orthopaedic Residency City, CA, US; Spine Institute of South Florida, Delray Beach, FL, 5 Program, Boston, MA, US; 3Brigham and Women's Hospital, US; Spine Institute, Los Angeles, CA, US Boston, MA, US; 4Brigham and Women's Hospital, Dept. of BACKGROUND CONTEXT: FIBERGRAFT® BG Putty is a resorbable Orthopedic Surgery, Boston, MA, US porous bone graft substitute made from proprietary 45S5 bioactive BACKGROUND CONTEXT: The role of telemedicine in the glass fibers. When the putty is placed in direct contact with viable evaluation and treatment of patients with spinal disorders is host bone, new bone grows in apposition to the surfaces of the rapidly expanding. Health systems are working to understand the implant. As the graft resorbs, bone and other connective tissues potential of this modality and optimally leverage telemedicine grows into the space previously occupied by the scaffold. for spine service line care delivery. Specifically, the ability of PURPOSE: To present the results of a retrospective clinical pain management specialists (e.g. physiatry and anesthesia) to evaluation of this bioactive glass (BG) putty for spinal fusion surgery accurately diagnose and plan appropriate interventional spine in ACDF or lumbar (posterolateral and/or interbody) fusions at four procedures based entirely on telemedicine visits, without an in- centers in the US. person evaluation, remains to be established. STUDY DESIGN/SETTING: IRB-approved, multi-center, PURPOSE: To characterize the relevance of telemedicine to retrospective clinical investigation of data obtained from patients interventional spine procedure planning by assessing whether who underwent anterior cervical or lumbar spinal fusions using BG procedure plans established solely from virtual visits changed Putty at 4 centers in the United States. following in person evaluation. PATIENT SAMPLE: Data was collected from a total of 102 patients STUDY DESIGN/SETTING: Retrospective cohort study. that consisted of adult men (n=58) and women (n=44) who PATIENT SAMPLE: We evaluated the records of patients who were underwent posterolateral and/or interbody fusion using BG Putty. indicated for interventional spine procedures with documented Patients were excluded if sufficient imaging was not available, if specific procedure plans during new visit virtual encounters additional bone graft materials other than autograft were used, or if (March-June 2020) and who then underwent subsequent in-person the reason for treatment was emergent traumatic injury. evaluation prior to the procedure. OUTCOME MEASURES: Primary outcome measures assessed OUTCOME MEASURES: The primary outcome of interest was successful post-operative bony fusion utilizing X-Ray and/or agreement between procedure plans generated by new virtual computed tomography (CT) scans, was utilized to assess bony visit encounter and in-person evaluation. Secondarily, we fusion. Fusion was defined as bridging bone between vertebral characterized the virtual physical examination maneuvers utilized body endplates, in interbody fusion, or between transverse by interventional spine specialists. processes in posterolateral fusion. Fusion failure was defined METHODS: We reviewed virtual and in-person clinical encounters as the absence of bridging bone or confirmed pseudoarthrosis. from our academic health system’s 10 interventional spine Secondary outcome measures included clinical outcomes and specialists (anesthesiology and physiatry). We included patients safety measures. who were seen exclusively via telemedicine encounters and METHODS: Patients underwent ACDF, lumbar interbody fusion indicated for an interventional procedure with documented (LIF) or posterolateral lumbar fusion with use of BG Putty with or procedural plans. Virtual plans were then compared to the actual without bone autograft. Autograft was used in conjunction with BG procedures performed following in person evaluation. Demographic Putty in approximately 52% of posterolateral lumbar fusion (PLF) data, patient primary complaint, and the type and extent of cases, 33% of lumbar interbody fusion (LIF) cases, and 73% of physical examination performed by the interventional spine ACDF cases. Subjects were treated in 1-4 level lumbar and cervical specialist were also recorded. spine fusion procedures (n = total 167 levels). RESULTS: Of the 87 patients included, the pre-procedural plan RESULTS: The overall fusion rate for all subjects was 94.1% established by telemedicine did not change for 76 individuals (96/102). Ninety-three percent (93.0% (53/57)) of the subjects (87%; 95% CI 0.79, 0.94) following in-person evaluation. Based on who underwent lumbar fusion were successfully fused with average the size of our sample, interventional procedures indicated solely follow-up time of 11.4 months postoperatively. In the cervical during telemedicine encounters may be accurate in 79-94% of spine, 95.6% (43/45) were successfully fused. With average follow- cases in the broader population. There was wide variation in the up time of 8.4 months postoperatively. Amongst the lumbar spine use of virtual physical examinations by interventional providers. procedures, 100% (46/46) of the subjects who underwent LIF CONCLUSIONS: Our findings suggest that telemedicine were successfully fused. For the 50 patients who underwent PLF, evaluations are a generally accurate means of pre-procedural 92% (46/50) were successfully fused. For the 39 patients who assessment and development of interventional spine procedure underwent both LIF and PLF, 100% (39/39) were successfully plans. These findings clearly demonstrate the capabilities fused. Clinical outcomes and safety were assessed as secondary of telemedicine for evaluating spine patients and planning endpoints at an average follow up of 13.8 months. Overall, trends of interventional spine procedures. improvement in disability and pain were observed in both cervical Proceedings 44

and lumbar cases. There were no deaths or unanticipated adverse to its adjacent segment. The intraclass correlation coefficients events reported, and no noted migrations or failures of the BG Putty of anterior-posterior, cranial-caudal, and angular change were material. calculated to be 0.75, 0.90, and 0.86, respectively. The average CONCLUSIONS: Patients treated with our BG Putty in anterior standard deviations of translational and rotational change were cervical and lumbar spine fusion procedures achieved a successful 3.3% and 2 degrees, respectively. fusion rates and trends of decreased patient reported pain and CONCLUSIONS: A model to comprehensively describe vertebral disability. These results compare favorably to those reported in the body motion as a method of characterizing subsidence was literature. There were no complications or adverse events related to successfully developed. The model had good to excellent reliability. the graft. Further refinement of the protocol may yield improved intraclass FDA DEVICE/DRUG STATUS: This abstract does not discuss or correlation coefficients. This method of measuring vertebral include any applicable devices or drugs. body motion is applicable to measuring modes of failure beyond subsidence such as fracture or delayed fusion. FDA DEVICE/DRUG STATUS: This abstract does not discuss or 37. A novel comprehensive model to describe include any applicable devices or drugs. vertebral body motion following interbody fusion Paul J. Johnson, MD, MS1; James T. Bernatz, MD2; Brian McGowan, MD3; Miranda Bice, MD4; Paul A. Anderson, MD5; Seth K. Williams, 38. Examination of a new external anal sphincter MD6 recording method for preventing intraoperative bladder rectal disorder 1University of New Mexico Health Sciences, Albuquerque, NM, US; 2Madison, WI, US; 3UW Health, Madison, WI, US; 4University Yoshikazu Yanagisawa, MD, PhD of Wisconsin Spine Medicine Clinic, Madison, WI, US; 5Univ of Fukuoka Mirai Hospital, Fukuoka, Japan Wisc Orthopedics & Rehabilitation, Madison, WI, US; 6University of BACKGROUND CONTEXT: Bladder and rectal disorder is one Wisconsin, Madison, WI, US of the serious intraoperative complications that greatly affects BACKGROUND CONTEXT: Subsidence of interbody fusion spinal the patient's quality of life. Spinal surgery is often performed implants occurs in up to 30% of interbody fusions. Previous in combination with nerve monitoring to prevent intraoperative methods to quantify subsidence of interbody implants have neuropathy, but the amplitude of the external anal sphincter focused on quantifying changes in disc height or magnitude of muscle (hereinafter referred to as EAS) is often small and difficult erosion of the implant into the vertebral body. These studies focus to evaluate in order to monitor bladder and rectal disorders. on the description of subsidence in a cranial-caudal direction. A Therefore, instead of the conventional method of inserting the comprehensive description of subsidence should report cranial- dual needle electrode into the left and right EAS, the method of caudal shift, anterior-posterior shift and angular shift of one combining the single needle electrode and the seal electrode vertebra with respect to its adjacent vertebra. attached to the coccyx has recently been used for monitoring. PURPOSE: The purpose of the study is to develop and validate a PURPOSE: This time, the usefulness was examined by comparing novel method that describes the motion of one vertebral body with the conventional method and the new recording method. respect to its adjacent vertebral body in terms of translation and STUDY DESIGN/SETTING: This study was an intervention study, rotation. We hypothesize this method would have satisfactory inter- and EAS was recorded at the transcranial electrical stimulation observer reliability. muscle-action potential (Br-MsEP), and the conventional method STUDY DESIGN/SETTING: Retrospective review of lumbar spine was anal1 and the new recording method was anal2. Br-MsEP radiographs at a tertiary academic center. amplitude of 30 μV or more was set as an effective record, and the PATIENT SAMPLE: Patients undergoing anterior lumbar interbody derivation rate of anal1 and 2 and the recording potential were fusion at L4-5 or L5-S1 with at least 1 year radiographic follow-up. compared and examined as examination items. OUTCOME MEASURES: The amount of cranial-caudal shift, PATIENT SAMPLE: Twenty-five patients (male: female 17: 8, anterior-posterior shift and angular shift on pre-operative, post- mean age: 67.2 years) who underwent spinal surgery under operative, and 1-year post-operative radiographs was recorded intraoperative nerve monitoring from May to July 2020 were according to the novel measurement technique. included. The diseases were lumbar spinal canal stenosis: 14 METHODS: A retrospective review of lateral lumbar spine cases, lumbar disc herniated disk: 5 cases, cervical spondylotic radiographs was performed by seven physicians (3 residents, myelopathy / posterior longitudinal ligament ossification: 4 cases, 2 fellows, and 2 attendings). The review included radiographic and others. analysis of 10 patients that underwent L4-5 or L5-S1 anterior OUTCOME MEASURES: Using the conventional method as anal1 interbody fusion. Preoperative, postoperative (day 1), and and the new recording method as anal2, the recording potentials 12-month postoperative radiographs were analyzed. Each vertebra of anal1 and 2 were compared and examined using the unpaired-t was defined in two-dimensional space by 4 peripheral points at the test. corners of the vertebral body and a centroid. The upper vertebra METHODS: All patients were managed under inhalation anesthesia was designated as a reference plane by which the motion of the (sevoflurane) and EAS was recorded at the transcranial electrical lower vertebra was measured. We measured the movement of the stimulation muscle-action potential (Br-MsEP). Br-MsEP amplitude lower vertebra in terms of anterior-posterior translation, cranial- of 30 μV or more was effective, and the derivation rate of anal1 caudal translation, and angular change immediately following and 2 and the recording potential were compared as examination lumbar interbody fusion and 12 months postoperatively to detect items, and the clinical course was also evaluated. translational and rotational subsidence. Inter-observer reliability RESULTS: The derivation rate was anal1: anal2 = 31.8%: 96.0%, was measured using SPSS software. and anal2 was able to derive better. The recording potential was RESULTS: A model was successfully developed to describe the 32.4 μV: 89.7 μV, which was significantly higher for anal2 (P = angular and translational change of one vertebral body with respect 0.00824). As a clinical course, constipation was observed in 2 Proceedings 45

cases before surgery, but improvement was observed in 1 case RESULTS: A total of 38,788 patients met inclusion criteria for this after surgery. In addition, there were no cases of bladder and rectal study. There were 4,470 major complications (11.5%). The XGBoost disorder after surgery. algorithm demonstrates the highest discrimination (AUROC: CONCLUSIONS: Intraoperative monitoring of EAS has a small 0.687 + 0.01) compared to LR (0.675 + 0.01), outperforming the amplitude, so it is often difficult to evaluate the waveform, and three other ML models. This model was well calibrated with a Brier it is possible to overlook the decrease in amplitude during the score of 0.094 + 0.001. The variables most important to XGBoost operation. Furthermore, spinal surgery under inhalation anesthesia performance include angina pectoris, metastatic cancer, teaching control has a weakness that the amplitude is small for a large hospital status, history of concussion, Charlson comorbidity score, stimulus intensity compared to TIVA-controlled spine surgery. In and workers’ compensation insurance. Notably, teaching hospital this study, anal2 had a higher derivation rate and a significantly status and concussion history were not found to be important in the larger amplitude than anal1. In addition, the amplitude of anal2 LR model. was clearly larger than in other reports, and it was considered CONCLUSIONS: Major perioperative complications and unplanned to be useful for evaluating bladder and rectal disorders due readmissions after lumbar fusion are a source of significant cost to intraoperative cauda equina disorders even in inhalation and morbidity; appropriate patient selection remains a challenge in anesthesia-controlled surgery. spinal surgery. We report an optimized ML algorithm for prediction FDA DEVICE/DRUG STATUS: This abstract does not discuss or of major perioperative complications and 30-day readmission after include any applicable devices or drugs. lumbar spinal fusion. The XGBoost model is well-calibrated and demonstrates superior risk prediction to LR. By providing accurate prognostic information, this algorithm may facilitate pre-operative 39. Development of an optimized machine learning shared decision-making and aid with appropriate patient selection. algorithm for prediction of complications and A physician must be able to provide patients with comprehensive readmission after lumbar spinal fusion and accurate information regarding risks and benefits in order for the patient to provide true informed consent. This tool may identify and 1 1 1 Akash A. Shah, MD ; Sai Devana, MD ; Changhee Lee, MS ; address potentially modifiable risk factors, helping to accurately risk- 2 3 Alexander Upfill-Brown, MD, MSc ; Elizabeth L. Lord, MD ; Don Y. stratify patients and decrease likelihood of major complications. 4 5 Park, MD ; Nelson SooHoo, MD FDA DEVICE/DRUG STATUS: This abstract does not discuss or 1Los Angeles, CA, US; 2David Geffen School of Medicine at UCLA, include any applicable devices or drugs. Los Angeles, CA, US; 3Santa Monica, CA, US; 4UCLA, Santa Monica, CA, US; 5UCLA Department of Orthopaedic Surgery, Los Angeles, CA, US 40. Minimum clinical important differences in BACKGROUND CONTEXT: Lumbar spinal fusion represents a outcomes at 1 year in the treatment of degenerated large and growing fraction of the healthcare system, with a 15- intervertebral discs using a viable disc tissue cellular fold increase in cases since 2002. The average age and number allograft of medical comorbidities of patients undergoing lumbar fusion Timothy T. Davis, MD1; Douglas P. Beall, MD2; H Thomas Temple, has similarly increased. Accurately risk-stratifying patients MD3; J. Kenneth Burkus, MD4 who undergo lumbar fusion would be of great utility, given the 1 2 significant cost and morbidity associated with developing major Source Healthcare, Santa Monica, CA, US; Clinical Radiology of 3 perioperative complications. There is a paucity of accurate and Oklahoma, Edmond, OK, US; Vivex Biologics, Inc., Miami, FL, US; 4 validated prediction models that can be used to pre-operatively Wilderness Spine Services, Columbus, GA, US risk-stratify patients for lumbar fusion. Advanced machine learning BACKGROUND CONTEXT: Discogenic pain is a common (ML) methods have grown in popularity across numerous medical cause of chronic low back pain (CLBP) and is one of the leading disciplines due to their ability to recognize complex, non-linear causes of disability and has a major socioeconomic impact. relationships – often outperforming logistic regression (LR). Treatment modalities have included noninvasive treatments, PURPOSE: We aim to develop an optimized ML algorithm for injections and surgical approaches. A viable disc tissue allograft prediction of major perioperative complication after lumbar fusion. has been developed to supplement tissue loss associated with Our secondary aim is to compare its performance against LR. intervertebral disc degeneration and the subsequent development of STUDY DESIGN/SETTING: Retrospective, cohort study. chronic discogenic lower back pain. PATIENT SAMPLE: Patients 18 years or older at a non-federal PURPOSE: An analysis of secondary subgroups from a primary California hospital who underwent lumbar spinal fusion. study of patients that were treated with a viable cellular disc OUTCOME MEASURES: Major perioperative complications, allograft that was injected into painful degenerated lumbar discs readmission within 30 days. was conducted. This investigation examines if Minimal Clinically METHODS: This is a retrospective cohort study of adult patients who Important Differences (MCID) in outcomes of improved pain and underwent instrumented or non-instrumented lumbar spinal fusion function were achieved for patients treated with viable disc tissue at any California hospital between 2015-2017. The primary outcome allografts when compared to a control cohort. was major perioperative complication – readmission within 30 days, STUDY DESIGN/SETTING: Assessment of changes in Oswestry venous thromboembolism within 30 days, myocardial infarction Disability Index (ODI) and Visual Analogue Scale (VAS) at 12 months within 7 days, pneumonia within 7 days, systemic infection within 7 following the transplant of viable allograft material into the affected days, surgical site bleeding within 90 days, and wound complications lumbar discs or randomization to a saline injection. within 90 days. We build LR and ML models that span different PATIENT SAMPLE: 218 patients with chronic low back pain classes of modeling approaches. Discrimination and calibration were secondary to one or two-level degenerative disc disease were assessed using area under the receiver operating characteristic analyzed. Patients had back and leg pain for a minimum of 6 curve (AUROC) and Brier score, respectively. We ranked the months that was recalcitrant to nonoperative treatment modalities contribution of the included variables to model performance. and injections. All had pre-treatment VAS ≥ 40 mm and ODI Score ≥ 40. Proceedings 46

OUTCOME MEASURES: Clinical outcome instruments used were RESULTS: There were 24 consecutive patients enrolled in this study ODI and VAS. The ODI MCID was considered >15 Points and a VAS (19 fusion, 5 decompression). Decompression patients walked MCID back pain reduction > 20 points. significantly more steps at each time point (Weeks 1-12) compared METHODS: Data from a multicenter, prospective, multicentered, to fusion patients. At week 1, decompression patients took an blinded randomized, clinical trial (RCT) for subjects with one or average of 3230 steps compared 2841 steps for fusion patients. two-level lumbar degenerative disc disease was analyzed. Subjects Decompression patients also were able to achieve 12,810 average were blinded and randomized to receive intradiscal injections of weekly steps by week 11, whereas fusion patients were only able either viable disc allograft or saline or to continue with non-surgical to average a maximum of 8312 weekly steps through the follow-up management (NSM). The NSM group could cross over to the period. Regression analysis showed that increasing number of weeks allograft group after 3 months. Patients were assessed at 6 and 12 post-surgery were predictors for increased number of steps taken. months. Age, BMI, and patient educational information were not predictive. RESULTS: At 12 months, improvements in mean VASPI and ODI CONCLUSIONS: Patients undergoing lumbar decompression can scores were achieved in both the investigational allograft and reach up to 12,810 weekly steps within 3 months of surgery while saline groups. However, at one year in the investigational allograft patients undergoing lumbar fusion can reach up to 8,312. Patients group, pain improved 34.8 points (54%) and was accompanied by undergoing lumbar decompression demonstrated significant a 27.1 point (53%) improvement in ODI. NSM subjects following improved mobility compared to their lumbar fusion counterparts. crossover attained a 45 point (65%) improvement in pain at 12 FDA DEVICE/DRUG STATUS: This abstract does not discuss or months combined with a 36.1 point (64%) improvement in ODI. include any applicable devices or drugs. A responder analysis demonstrated statistical significance when evaluating a MCID in ODI of ≥15 points at 12 months; 76.5% of subjects randomized to allograft were responders as compared Wednesday, July 7 to 56.7% in the saline group (p = 0.03). Higher responder rates 5:00–6:00 p.m. of 66.7% and 91.3% of patients in the allograft and cross over to Deformity allograft groups versus 56.7% in the saline group were observed when evaluating a MCID of ≥ 20 points in back pain improvement (p=0.022). 42. Use of topical tranexemic acid reduces effective CONCLUSIONS: This large, prospective blinded RCT demonstrated blood loss and transfusion requirements in spinal outcomes suggesting that viable disc tissue allograft may be a deformity correction in patients with adolescent beneficial non-surgical treatment for patients that have chronic idiopathic scoliosis painful lumbar degenerative discs. Subjects treated with viable disc Blaze Emerson, DO1; Subaraman Ramchandran, MD2; Stephen tissue allograft exhibited statistically significant improvements that G. George Jr, MD2; Thomas J. Errico, MD3; Ali Mansour, MD4; exceeded the MCID for both functional and pain outcomes. Alexander Mihas, BS5 FDA DEVICE/DRUG STATUS: This abstract does not discuss or 1 2 include any applicable devices or drugs. Broward Health Medical Center, Ft Lauderdale, FL, US; Nicklaus Children's Hospital, Miami, FL, US; 3Center for Spinal Disorders, Orthopedic Surgery, Nicklaus Children’s Hospital, Miami, FL, US; 4 5 41. Patient mobilization with activity trackers Winnipeg Spine Program, Winnipeg, Canada; Miami, FL, US following lumbar fusion and decompression BACKGROUND CONTEXT: Systemic administration of Tranexemic acid has shown to significantly reduce blood loss in spinal Hao-Hua Wu, MD1; Andrew Logan, MD2; Steven Wright, BS3; Lionel deformity correction. Few recent studies have shown the potential N. Metz, MD4 benefit of application of TXA soaked sponges in reducing blood 1San Francisco, CA, US; 2Jackson - PM&R, Miami, FL, US; loss in posterior lumbar spine surgeries. Role of topical TXA as an 3California Northstate University, Elk Grove, CA, US; 4UCSF Dept. of adjunct to conventional blood salvage techniques in adolescent Orthopaedic Surgery, San Francisco, CA, US spinal deformity correction is unclear. BACKGROUND CONTEXT: There remains a dearth of literature PURPOSE: To evaluate the effectiveness of the use of topical evaluating the use continuous activity trackers to augment recovery tranexemic acid in spinal deformity correction in AIS patients from spine surgery. The potential advantage of using mobile activity STUDY DESIGN/SETTING: Retrospective review of prospectively trackers is the ability to provide continuous, objective data of collected database. ambulatory function and activity level. PATIENT SAMPLE: Prospectively collected sample of adolescent PURPOSE: The purpose of this study is to use activity trackers to idiopathic scoliosis patients collected at Nicklaus Children's compare mobilization of patients undergoing lumbar fusion and Hospital treated by two surgeons. lumbar decompression. OUTCOME MEASURES: 1. Mean estimated percentage of METHODS: In this prospective observational study at a single circulating blood volume lost during surgery. 2. Estimated blood academic institution, adult patients undergoing one-level or two-level loss per level. 3. Drain output. 4. Change in hemoglobin levels. 5. lumbar decompression or fusion operations were enrolled between Peri-operative complication rates. March and June 2017. Each patient was given a mobile activity METHODS: Sixty consecutive operative Adolescent Idiopathic tracker with an accelerometer to be worn daily. Step trajectory, Scoliosis (AIS) patients were reviewed from a single institution weekly steps, and total steps achieved were measured continuously and were divided into two groups with similar age, weight, gender, for 12 weeks. A regression analysis using generalized estimating curve severity, number of levels fused, co-morbid conditions and equations techniques (GEE) to examine the association between medications. Standardized peri-operative blood salvage techniques group assignment and number of steps walked over the course of the were utilized in all 60 patients. In the latter 30 patients, topical TXA study. soaked sponges (1g mixed in 500ml Normal Saline) was utilized for wound packing during the surgical procedure compared to dry Proceedings 47

sponges as used in the former 30 patients (control group). Both using a commercially available 2D/3D modelling software. ANOVA the groups were compared for magnitude of deformity corrected, and Tukey’s HSD for post-hoc analysis were used to determine the estimated blood loss (EBL) per level fused, total EBL, Cell-saver differences between groups. and blood transfused, post-op drain output, peri-operative RESULTS: The results showed that three of the studied spino-pelvic complications, change in hemoglobin and length of stay. parameters, which are respectively LL, PT and PI-LL, increase RESULTS: Sixty AIS patients (mean age: 14.4 yrs, 43 females, according to the PI value. As a major result, a simple linear regression mean BMI: 21.5, mean levels: 10.7) were included. Both groups analysis between PI and other parameters allow to find an adequate achieved similar change in Coronal Cobb correction. The mean equation to respectively estimate LL or PT or PI-LL according to PI estimated percentage of circulating blood volume lost in the value. After population clusterization according to PI, the results topical TXA group was 38% less than the control group (11.2 vs. show a significant variation in the mean LL in each group. 18.3%, p=0.006). Similarly, the EBL per level was significantly CONCLUSIONS: PI showed significant correlation with PT, LL lower in the topical TXA group (41 ± 30ml vs. 57 ± 26ml, p=0.03). and PI-LL. The normal value of PI-LL considering PI and the linear Twelve of 30 patients in the control group required at least 1 unit of regression equation in this study could help to evaluate the sagittal blood transfusion, whereas only 1 patient in the topical TXA group alignment and provide reference value for planning to establish the required transfusion (40 vs. 3.3%, p=0.001). No differences were target restoration of sagittal curve in corrective surgery. noted in post-operative drain output, change in hemoglobin levels FDA DEVICE/DRUG STATUS: This abstract does not discuss or and peri-operative complication rates. include any applicable devices or drugs. CONCLUSIONS: When used as an adjunct to the conventional blood salvage techniques in spinal deformity correction procedures, use of topical TXA sponges resulted in reduced 44. How to reduce implant-related complication operative blood loss, and blood transfusion requirements. No rates, pseudo, and revision surgery in adult spinal complications were associated with the use of topical TXA. deformity surgery FDA DEVICE/DRUG STATUS: tranexemic acid (Approved for this 1 2 3 indication) Mitsuru Yagi, MD, PhD ; Satoshi Suzuki, MD ; Ejiiro Okada, MD ; Satoshi Nori, MD, PhD1; Osahiko Tsuji, MD, PhD4; Narihito Nagoshi, MD, PhD5; Masaya Nakamura, MD, PhD1; Morio Matsumoto, MD2; 2 43. The correlation analysis of pelvic incidence Kota Watanabe, MD minus lumbar lordosis with pelvic incidence from a 1Department of Orthopedic Surgery, Keio University School of database of 488 asymptomatic volunteers Medicine, Tokyo, Japan; 2Keio University, Tokyo, Japan; 3Saiseikai Central Hospital, Tokyo, Japan; 4, Saitama, Japan; 5Toronto Western 1 2 Jean-Charles Le Huec, MD, PhD ; Stéphane Bourret, PhD ; Hospital, Toronto, ON, Canada Zeeshan Sardar, MD, MSc3; Meghan Cerpa, MPH4; Kazuhiro Hasegawa, MD, PhD5; Hwee Weng Dennis Hey, MBBS, FRCS6; BACKGROUND CONTEXT: Mechanical failure (MF) following Michael P. Kelly, MD7; Lawrence G. Lenke, MD8 surgery for adult spinal deformity (ASD) is a severe postoperative complication and often requires planned and unplanned revision 1 2 Bordeaux, France; Polyclinique Bordeaux Nord Aquitaine, surgery. Various types of symptomatic and asymptomatic MF can 3 Bordeaux, France; New York-Presbyterian The Allen Hospital, New be developed following ASD surgery (proximal junctional kyphosis/ 4 York, NY, US; Columbia University Medical Center, New York, NY, failure [PJK/PJF], distal junctional kyphosis [DJK], rod failure [RF]). 5 6 US; Niigata Spine Surgery Center, Niigata City, Japan; National The postoperative MF rates for ASD have been reported to be as 7 University Health System, Singapore, Singapore; Saint Louis, MO, high as 50%. Several previous studies have described the poor 8 US; Department of Orthopedic Surgery, Keio University School of prognosis of patients who developed neurological deficits following Medicine, Tokyo, Japan MF. Various risk factors for MF have been reported, including age, BACKGROUND CONTEXT: PI-LL mismatch was established as a spinal misalignment requiring a large correction, osteoporosis, and sagittal parameter with a threshold of less than 10° for achieving the application of pedicle subtraction osteotomy (PSO). However, good HRQOL. However, some articles have postulated that the it is still difficult to prevent or minimize the risk of complications of threshold of the PI-LL cannot be set as a fixed numeric value and individuals following ASD surgery. should consider PI value in the global population. To our best PURPOSE: This study aimed to establish ASD-specific risk knowledge, there have been studies on PI-LL for postoperative stratification model for predicting the risk of MF using the individual’s patients with adult spinal deformity, but no studies have been demographic and radiographic, and surgical description data. conducted on asymptomatic patients and reported normal range of STUDY DESIGN/SETTING: This is a multicenter retrospective PI-LL on the basis of PI. review of the risk stratification for MF. PURPOSE: The purpose of the study is to establish the normative PATIENT SAMPLE: This study included 321 surgically treated ASD value for PI-LL based on the data of 488 asymptomatic volunteers. patients (55 ± 19 yr, female: 91%). STUDY DESIGN/SETTING: Prospective cohort study. OUTCOME MEASURES: Development of MF PATIENT SAMPLE: 488 asymptomatic adult volunteers. METHODS: The analyzed variables were recorded for at least 2 yr OUTCOME MEASURES: PI-LL mismatch was correlated with other and included age, gender, BMI, BMD, smoking status, frailty, fusion spino plevic parameters according to PI value (PI < 45°; 45° 60°). GAP score, Schwab-SRS type, and rod materials. Multivariate logistic METHODS: Full-body low dose stereoradiographic evaluation was regression analyses were performed to identify the independent risk done in a multi-ethnic cohort of 488 asymptomatic adult volunteers factors for MF. Each risk factor was assigned a value based on its (Mean age: 40.8; Range: 18-79 years). Patients from 5 different regression coefficient, and the values of all risk factors were summed centers were included (France, Japan, Singapore, Tunisia, and to obtain the PRISM score (range 0-12). We used an 8:2 ratio to split the United States). Volunteers were divided into 3 main groups the data into a training and a testing cohort to establish and validate depending on PI values: PI60°. 3D measurements were performed the model. Proceedings 48

RESULTS: MF developed in 41% (n=104) of the training subjects. RESULTS: Of 140 enrolled patients, 42 (30%) underwent AVBT and Multivariate analysis revealed that BMI, BMD, PT, and frailty were 98 (70%) underwent PSF. AVBT and PSF patients had no difference independent risk factors for MF (BMI: OR 1.7 [1.0-2.9], BMD: OR 3.8 in 30-day readmission (5% vs. 3%, p=0.63). AVBT patients had [1.9-7.7], PT: OR 2.6 [1.8-3.9], frailty: OR 1.9 [1.1-3.2]). The MF rate shorter procedure time (296±88 minutes vs. 428±75 minutes, increased with and correlated well with the risk grade as shown by p<0.01), less EBL (117.7±116 ml vs. 210.4±180 ml, p<0.01), shorter ROC curve (AUC of .81 [95% CI .76–.86]). The discriminative ability LOS (3.6±0.91 days vs. 4.7±2.0 days, p<0.01), less total inpatient of the score in the testing cohort was also good (AUC of .86 ([95% CI OME use (p<0.05), shorter foley duration (58±19 hours vs. 65±19 .77–.95]). hours, p=0.04), less days to solid food (0.9±0.4 vs. 1.2±1.1, p=0.03) CONCLUSIONS: In the present study, we established a mechanical and decreased overall direct cost in USD ($42,157.10±$14,459 failure predictive model based on individual demographics, baseline vs. $50,277.00±$13,905, p<0.01) compared to PSF patients. The spinal alignment, and surgical descriptive data. The advantages overall revision rate at least two years postoperatively was higher in of the model include the feasibility of the scoring system. This patients undergoing AVBT than PSF (36% vs. 11%, p<0.01). scoring system consists only of preoperative values and therefore CONCLUSIONS: Patients who underwent AVBT had equivalent can be fully assessed before surgery. The model also showed good 30-day readmission rate as well as decreased surgery time, EBL, accuracy for predicting the incidence of MF in both the training LOS, inpatient OME use, foley duration, days to solid food and overall and testing cohorts, with an AUC of .81 in the training subjects direct cost compared to PSF patients. At two years postop, AVBT and of .86 in the testing subjects. In the present study, we enrolled patients had three times the rate of revision compared to those who patients from 7 surgeons in 3 academic hospitals in an East Asian underwent PSF. These data can be used in the informed consent country, so the patients were mostly Asian. Therefore, our results process for the surgical management of skeletally immature patients cannot necessarily be extrapolated to all other hospital settings. with idiopathic scoliosis. We successfully developed an MF-predicting model from individual FDA DEVICE/DRUG STATUS: This abstract does not discuss or baseline parameters. This model can predict a patient’s risk of MF include any applicable devices or drugs. and will help surgeons adjust treatment strategies to mitigate the risk of MF. Further analyses including different patient populations are necessary to validate the predictive power of our model for MF 46. The impact of preoperative cross-sectional area following ASD surgery. of psoas muscle on postoperative outcomes of adult FDA DEVICE/DRUG STATUS: This abstract does not discuss or spinal deformity surgery include any applicable devices or drugs. Hikari Urakawa1; Kosuke Sato, MD2; Jonathan Elysee1; Renaud Lafage, MSc1; Avani S. Vaishnav, MBBS1; Yu-Cheng Yao, MD3; 1 1 1 45. Perioperative outcomes of anterior vertebral Han Jo Kim, MD ; Frank J. Schwab, MD ; Virginie Lafage, PhD ; Catherine Himo Gang, MPH1; Sheeraz A. Qureshi, MD, MBA1 spinal tethering versus posterior spinal fusion for skeletally immature patients with idiopathic 1Hospital for Special Surgery, New York, NY, US; 2New York, NY, US; 3 scoliosis Taipei Veterans General Hospital, Taipei, Taiwan Hao-Hua Wu, MD1; Satvir Saggi, BS2; Toshali Katyal, BA3; Sachin BACKGROUND CONTEXT: Proximal junctional kyphosis (PJK)/ Allahabadi, MD4; Jeremy Siu, BS1; Mohammad Diab, MD5 proximal junctional failure (PJF), which is caused by soft tissue or bony failure, is a critical challenge in adult spinal deformity (ASD) 1 2 3 San Francisco, CA, US; Milpitas, CA, US; Oakland, CA, US; surgery. The cross-sectional area of psoas muscle has been used as 4 University of California, San Francisco Department of Orthopaedic a parameter of sarcopenia and reported to have a negative impact 5 Surgery, San Francisco, CA, US; University of California - San on clinical outcomes after lumbar surgery. However, it is unclear Francisco (UCSF), San Francisco, CA, US whether it also impacts outcomes of ASD surgery. BACKGROUND CONTEXT: Correcting scoliosis without fusion can PURPOSE: To examine the impact of preoperative cross-sectional be achieved with anterior vertebral body tethering (AVBT). However, area of psoas muscle on postoperative outcomes of ASD surgery. little is known about the perioperative morbidity of AVBT compared STUDY DESIGN/SETTING: Retrospective cohort study. with traditional posterior spinal fusion and instrumentation (PSF). PATIENT SAMPLE: 65 ASD patients who were over 18 years old and PURPOSE: The purpose of this study is to compare the perioperative underwent posterior fusion surgery with more than 5 levels with 6 outcomes of AVBT versus PSF in skeletally immature patients with months follow-up. idiopathic scoliosis. OUTCOME MEASURES: Patient reported outcome measures STUDY DESIGN/SETTING: Retrospective cohort study. (PROMs) including ODI, SRS-22, radiographic parameters including PATIENT SAMPLE: Skeletally immature patients with idiopathic PT, PI, SS, LL, SVA, C2-C7 SVA, C2-T3 SVA, TS, TK, TPA and Cobb scoliosis curve magnitude of at least 40 degrees with at least two- angle at pre-op and 6 months, and prevalence of PJK/PJF at 6 year follow-up who underwent AVBT or PSF from 2014-2018 were months. included. Patients with neuromuscular scoliosis were excluded. METHODS: The cross-sectional area of psoas muscle was measured OUTCOME MEASURES: The primary outcome is 30-day at L3/4 on T2-weighted axial images of preoperative MRI. Normalized readmission. Secondary outcomes include procedure duration, total psoas area (NTPA) (mm2/m2) was calculated as total psoas estimated blood loss (EBL), length of stay (LOS), total postoperative area normalized to patient height. Outcomes were compared opioid morphine equivalent (OME), foley duration, days to solid food, between patients with the lowest sex-specific quartile of NTPA [low direct cost and revision surgery. NTPA group (LG)] and the remainder [high NTPA group (HG)]. METHODS: In this IRB-approved retrospective cohort study, RESULTS: There were no significant differences in PROMs operatively managed skeletally immature patients with scoliosis between groups at all points, however, ODI and SRS-22 including curve magnitude of at least 40 degrees were enrolled and compared all sub-items except for mental health were worse in the LG at 6 with respect to primary and secondary outcomes. months, compared to the HG. In radiographic parameters, C2-C7 SVA was significantly higher in the LG at pre-op and 6 months (LG Proceedings 49

34.2±14.8vs. HG 26.4±11.8, p=0.040 at pre-op; LG 34.5±17.4 vs. Thursday, July 8 HG 26.9±10.3, p=0.044 at 6 months). SS was significantly lower in the LG at pre-op and 6 months (LG 25.0±11.3 vs. HG 33.9±12.7, 12:00–1:30 p.m. p=0.013 at pre-op; LG 30.9±7.9 vs. HG 37.9±10.8, p=0.025 at 6 Thoracolumbar Surgery months). Prevalence of PJK was significantly higher in the LG (LG 50.0% vs. HG 18.4%, p=0.021), compared to the HG, while there 49. Microendoscopic decompression for lumbosacral were no patients with PJF in both groups. foraminal stenosis: A novel surgical strategy based CONCLUSIONS: The decrease of psoas cross-sectional area on on anatomical considerations using 3D image fusion preoperative MRI significantly increased prevalence of PJK. It was with MRI/CT also associated with higher C2-C7 SVA and lower SS before surgery Hiroshi Yamada, MD, PhD and at 6 months. FDA DEVICE/DRUG STATUS: This abstract does not discuss or Wakayama Medical University, Dept of Orthopaedic Surgery, include any applicable devices or drugs. Wakayama, Japan BACKGROUND CONTEXT: Persistent lumbar foraminal stenosis (LFS) is one of the most common reasons for poor postoperative 47. Moved to Adult Spinal Deformity outcomes and is a major contributor to “failed back surgery syndrome.” PURPOSE: The aim of this study is to propose a new surgical 48. Spinopelvic sagittal alignment as predictor of strategy for LFS based on anatomical considerations using 3D image adjacent segment disease after transforaminal fusion with MRI/CT analysis. lumbar interbody fusion STUDY DESIGN/SETTING: A retrospective review. PATIENT SAMPLE: 78 consecutive patients surgically treated for Ghanshyam Kakadiya, MS, MBBS LFS at the lumbosacral junction. Department of Spine Surgery, Mohali, Panjab, India OUTCOME MEASURES: Lumbar (low-back pain, leg pain) and BACKGROUND CONTEXT: Adjacent segment disease (ASD) patient satisfaction visual analog scale (VAS) scores and Japanese is a potential long-term complication of spinal fusion surgeries, Orthopaedic Association (JOA) scores were evaluated. Surgical which could lead to deterioration of the surgical outcome and outcome was evaluated 2 years postoperatively. the requirement of further surgical treatment. Sagittal balance METHODS: The location and extent of stenosis, including the is considered to be important to the development of the whole narrowest site and associated pathology (bone or soft tissue), were physiologic spine, which maintains alignment with minimum energy measured using 3D image fusion with MRI/CT. Stenosis was defined expenditure. as medial intervertebral foraminal (MF; inner edge to pedicle center), PURPOSE: This study was carried out to explore the diagnostic lateral intervertebral foraminal (LF; pedicle center to outer edge), or value of spinopelvic sagittal measurements for adjacent segment extraforaminal (EF; outside the pedicle). disease (ASD) after transforaminal lumbar interbody fusion (TLIF). RESULTS: Most instances of stenosis existed outside the pedicle’s STUDY DESIGN/SETTING: A Prospective study center (94%), including LF (58%), EF (36%), and MF (6%). In all MF PATIENT SAMPLE: 163 cases, stenosis resulted from soft-tissue structures. The narrowest OUTCOME MEASURES: Sagittal alignment including thoracic inlet stenosis sites were localized around the pedicle’s outer border. The and spinopelvic parameters was measured by using preoperative areas for sufficient nerve decompression were extended in MF+LF full-length free-standing radiographs. Multivariate logistic regression (10%), MF+LF+EF (14%), LF+EF (39%), LF (11%), and EF (26%). analysis was performed to evaluate these parameters as the No iatrogenic pars interarticularis damage occurred. The JOA score diagnostic index for ASD. was 14.9 ± 2.6 points preoperatively and 22.4 ± 3.5 points at 2 years METHODS: A total of 163 subjects who underwent TLIF for the postoperatively. The JOA recovery rate was 56.0% ± 18.6%. The VAS lumbar disease were initially enrolled in the study from July 2014 score (low-back and leg pain) was significantly improved 2 years to August 2018. Sagittal alignment including thoracic inlet and postoperatively (p < 0.01). According to patients’ self-assessment spinopelvic parameters was measured by using preoperative full- of the minimally invasive surgery, 62 (79.5%) chose “surgery met length free-standing radiographs. Multivariate logistic regression my expectations” at followup. Nine patients (11.5%) selected “I did analysis was performed to evaluate these parameters as the not improve as much as I had hoped but I would undergo the same diagnostic index for ASD. surgery for the same outcome.” RESULTS: A total of 153 patients completed the final follow-up, and CONCLUSIONS: Most LFS existed outside the pedicle’s center the mean follow-up period was 40.6 months. There were 53 (35.3%) and was rarely noted in the pars region. The main regions of cases with ASD found after the TLIF in the enrolled subjects. Logistic stenosis were localized to the pedicle’s outer edge. Considering this regression analysis and receiver operating characteristic analysis anatomical distribution of LFS, the authors recommend that lateral confirmed that preoperative pelvic tilt (PT) of more than 24.1 and fenestration should be the first priority for foraminal decompression. thoracic kyphosis (TK) of more than 23.3 were significant risk factors Other surgical options including foraminotomy, total facetectomy, of ASD after TLIF (P < 0.05). and hemilaminectomy likely require more bone resections than CONCLUSIONS: We confirmed that PT of more than 24.3 and TK of LFS treatment. The microendoscopic surgery results were very more than 23.3 could be regarded as predictors of ASD after lumbar good, indicating that this minimally invasive surgery was suitable for TLIF. treating this disease. FDA DEVICE/DRUG STATUS: This abstract does not discuss or FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. include any applicable devices or drugs. Proceedings 50

50. Clinical comparison of biportal endoscopic spine 51. Surgical treatment of primary mobile spine surgery versus microscopic spine surgery for lumber chordoma disc herniation. Joshua Kolz, MD, MS1; Matthew Houdek, MD1; Michael J. Takaki Yoshimizu, MD1; Kanji Sasaki, MD, PhD2 Yaszemski, MD, PhD2; Peter Rose, MD3; Elizabeth Wellings, MD, MEng1; Michelle J. Clarke, MD1 1Seirei Hamamatsu General Hospital, Hamamatsu, Japan, Shizuoka, Japan; 2Hamamatsu, Japan 1Mayo Clinic, Rochester, MN, US; 2Rochester, MN, US; 3Mayo Clinic Dept of Orthopedic Surgery - Gonda 14, Rochester, MN, US BACKGROUND CONTEXT: Both biportal endoscopic spine surgery: BESS and microscopic spine surgery are minimally invasive BACKGROUND CONTEXT: Chordomas are rare primary bone technique. For many spine surgeons in Japan, microLOVE method is tumors which arise from notochordal remnants and make up less a common procedure to treat lumber disc herniation. On the other than 5% of all bone tumors. However, they are responsible for hand, BESS is newly technique using arthroscopic systems and not approximately 20% of primary malignant bone tumors arising in the familiar in Japanese spine surgeon. We have treated all LDH cases spine. Prior studies have shown a high rate of local recurrence and with BESS from when we induced this technique from 2019. We low overall survival, while patients undergoing en bloc (Enneking compared the results of these two procedures. appropriate) and gross total resection tend to have lower recurrence PURPOSE: In this study, we report the clinical comparison of rates and longer overall survival. Given the paucity of data regarding biportal endoscopic spine surgery versus microscopic spine surgery primary chordomas of the mobile spine, the preferred treatment for lumber disc herniation. method remains a debated topic. STUDY DESIGN/SETTING: Case-control study. PURPOSE: The purpose of this study was to review the outcome PATIENT SAMPLE: The subjects were 101 patients who had of surgical treatment for patients with a primary mobile spine been treated for hernia surgery for two years from October 2017, chordoma. 50 patients who underwent herniotomy by BESS, and 51 cases STUDY DESIGN/SETTING: Retrospective review at a large tertiary who underwent Micro LOVE. There was no difference in indication referral center. between the two operations. During the first half of period, the PATIENT SAMPLE: 26 patients undergoing surgical resection patients was treated by Micro LOVE and the second half was BESS. for a mobile spine chrodoma (17 intralesional procedures, 9 en OUTCOME MEASURES: The average age was 45 years. Outcome bloc). Tumor location included cervical (n=12, 46%), thoracic (n=3, Measures: Examination items were surgical time, amount of 12%) and lumbar (n=11, 42%) spine. The final resection margin was bleeding, hospitalization periods, pain on the next day and discharge positive in 18 (69%) patients (17/17 with intralesional procedures, (NRS) and recurrence rate. 1/9 with en bloc procedures). Radiotherapy was used in 14 (54%) METHODS: For the test, χ2 test and t test were used. patients to assist with margin control. Mean follow-up was 12±6 RESULTS: The average operation time was 74 minutes in the years. BESS group, 63 minutes in the micro Love group, and significantly OUTCOME MEASURES: Outcome measured included local and longer in the BESS group. The BESS group averaged 8g, and the distant recurrence, disease specific and overall survival, need for Love group averaged 14g. There was no significant difference in the revision surgery and complications. length of hospitalization. The pain on the next day after surgery was METHODS: We identified 26 patients diagnosed with a primary not significantly different from 3.4 in the BESS group and 3.2 in the chordoma in the mobile spine (C1-L5). Patients with a recurrent micro LOVE group. The recurrence in BESS group was 2 cases and chordoma, chordoma in a location other than the mobile spine the open group was 8 cases. (sacrococcygeal, skull base, nasopharyngeal etc), or who were CONCLUSIONS: After we switched to endoscopic surgery form treated non-operatively were excluded. Patient charts were then micro surgery, it was smooth without complications from the first reviewed for patient, tumor, and surgical characteristics, adjuvant case. BESS uses two portals, which is different from conventional treatment(s), intraoperative and postoperative complications, need endoscopic spine surgery like PED / MED. The advantage is that the for revision surgery, tumor recurrence (local vs distal), and survival visual field can be kept clear by always draining, and the working at latest follow-up. Local recurrence was defined as chordoma freedom is increased by separating the work axis and the visual axis. recurrence at the same or adjacent vertebral level, while distant Because of these advantages, spinal endoscopic surgery, which is recurrence was defined as metastatic recurrence at a vertebral level thought to require advanced technical skills, can be performed more that was more than one level from the initial resection margins, or easily. In fact, it took about an hour from our first patient. Also, BESS to another organ system. Surgical resection was defined as one of does not require any special instruments, and there is almost no three types of operations, en bloc resection, gross total resection, or initial investment required for the introduction of the procedure in planned debulking. facilities where arthroscopic surgery can be performed. RESULTS: The mean 2-, 5- and 10-year disease free survivals were FDA DEVICE/DRUG STATUS: This abstract does not discuss or 95%, 61% and 55%. En bloc procedures trended towards improved include any applicable devices or drugs. oncologic outcomes. Local recurrence free survival was improved in patients receiving Enneking appropriate resection (83% vs 35%, p=0.02) and similar in patients receiving adjuvant radiation therapy (43% vs 45%, p=0.30) at 10 years. Debulking of the tumor (HR 6.41, p=0.01) and a local recurrence (HR 9.52, p=0.005) were associated with death due to disease. The 10-year local recurrence and metastatic free survivals were 50% and 61%, respectively. Debulking of the tumor (HR 12.42, p<0.001) was associated with local tumor recurrence. Tumor size ≥ 5 cm (HR 5.16, p=0.01) and a local recurrence (HR 5.66, p=0.03) were associated with metastatic disease. Complications occurred in 19 (73%) patients, leading to a Proceedings 51

reoperation in 9 (35%) patients; this rate was similar in intralesional failure (HR=1.56, 95% CI: 1.19-2.04, p=0.020). PSF and TLIF+PSF and en bloc procedures. were associated with lower risk of revision, compared to ALIF+PLF CONCLUSIONS: Surgical resection of mobile spine chordomas is (ALIF+PSF Reference; PSF: HR=0.39, 95% CI=0.27-0.55, p<1E- associated with a high rate of complications; however surgical en 05; TLIF+PSF: HR=0.56, 95% CI=0.40-0.79, p=0.02). Male gender bloc resection can provide a hope for cure and appears to confer was associated with significantly reduced risk of revision for better oncologic outcomes for these difficult tumors without an degenerative disease (Female Reference; Male: HR=0.75, 95% CI increase in complications compared to lesser surgical procedures. =0.62-0.91, p=0.04). Age, race, CCI, and physician and hospital FDA DEVICE/DRUG STATUS: This abstract does not discuss or fusion volumes had no effect on risk of revision. include any applicable devices or drugs. CONCLUSIONS: In this database analysis, the 5-year revision rate was 16.5% following elective multi-level lumbar instrumented fusions in elderly (>60 years) patients. Degenerative disease and 52. Five-year revision rates for elective multi-level mechanical failure were identified as the most common causes of lumbar instrumented fusions in the elderly: An revision operations. These data may prove fruitful in pre-operative analysis of state databases counseling and aid in shared decision making of elderly patients considering a multi-level lumbar instrumented fusion. 1 2 Daniel D. Cummins ; Alexander A. Theologis, MD FDA DEVICE/DRUG STATUS: This abstract does not discuss or 1UCSF, San Francisco, CA, US; 2UCSF Spine Center, San Francisco, include any applicable devices or drugs. CA, US BACKGROUND CONTEXT: Revision operations following multi-level lumbar fusion surgery create significant burden on patient quality 53. Physical therapy on postoperative day 0 following of life and healthcare costs. As such, counseling patients on risks of lumbar spine surgery decreases length of stay revisions and potential modifiable factors are of utmost importance. Blaine Manning, MD1; Nathan Cherian2; Ahdarsh Vallabhaneni1; PURPOSE: Evaluate 5-year revision rates and indications and Stefan Hanish, BS2; Andrew Lee1; Suryanshi Rawat, BS3; Casey modifiable risk factors for revision operations following elective multi- A. Fogarty3; Mark Lambrechts, MD3; Fassil B. Mesfin, MD, PhD4; level lumbar instrumented fusions in elderly patients. Muhammad Z. Mirza, MD3; Theodore J. Choma, MD5; Don K. STUDY DESIGN/SETTING: Retrospective cohort analysis Moore, MD6 PATIENT SAMPLE: Elderly patients (>60 years) who underwent 1Columbia, MO, US; 2University of Missouri School of Medicine, multi-level (3+ level) lumbar instrumented fusions, based upon ICD9 Columbia, MO, US; 3Missouri Orthopaedic Institute, Columbia, coding, identified in the Health Care Utilization Project (HCUP) state MO, US; 4University of Missouri Health Care, Columbia, MO, US; inpatient databases from Florida (2005-2014) and California (2005- 5Missouri Spine Center, Columbia, MO, US; 6University of Missouri, 2011). Operations for non-elective indications (i.e. fractures, tumor, Columbia, MO, US infections) were excluded. OUTCOME MEASURES: Patients were followed for 5 years and BACKGROUND CONTEXT: Postoperative length of stay (LOS) any subsequent revision operations and associated indications is a major factor in overall cost for lumbar spine surgery, and its for revisions [degenerative disease (adjacent segment disease, duration often depends on discharge clearance from physical spondylosis, degenerative disc disease), infection, mechanical therapy (PT). failure (including pseudarthrosis), post-laminectomy syndrome, PURPOSE: The study goal was to compare postoperative length of stenosis] were identified. Cox proportional hazards analysis was stay for lumbar spine surgery patients who initiated formal physical carried out using multivariate analysis to determine risk factors therapy on postoperative day (POD) 0 versus POD 1. associated with revision operations for each given diagnostic cause. STUDY DESIGN/SETTING: Retrospective cohort study. METHODS: Classification of reason for revision surgery was METHODS: A retrospective review was conducted of 1,870 performed using categorization of ICD9 coding at time of revision patients who underwent elective 1-2 level laminectomy +/- surgery. Revision rates were calculated by the percentage of posterior lumbar fusion +/- instrumentation by 13 spine surgeons patients in the stated cohort who received reoperations within one at 1 institution from 2011-2019. Patients were categorized by to five years. The following covariates were included in the Cox timing of postoperative PT, with POD 0 defined as within 24 hours proportional hazards analysis: age, race, Charlson comorbidity after surgery. Patients were excluded if they had incomplete index (CCI), gender, operative approach [posterior lumbar fusion data, admitted under a trauma visit, admitted to the ICU between (PSF), TLIF+PSF, and ALIF +PSF], hospital and physician fusion surgery and discharge for observation or complications, did not volumes, length of stay, and revision procedure coded at index see PT before discharge, or had qualifying surgery at >2 levels. operation. Competing-risks analysis was carried out using Demographics, perioperative variables, and postoperative cause-specific hazard modeling. In the competing risks analysis, variables were collected. Statistical methods for categorical death, degenerative disease, infection, mechanical failure, post- bivariate analysis included Chi-square test of independence and laminectomy syndrome, and stenosis were included as an outcome Fisher’s Exact test, if Chi-square assumptions were not met. For variable. continuous outcomes, normality was tested using a Shapiro-Wilk RESULTS: 5,636 patients (female-3,285; avg. age at index test and a two-sample t-test or Wilcoxon Rank Sum test was used operation 71.6 +/- 6.56 years were included for analysis. The to determine differences across POD groups. Data were analyzed majority of index operations were 3-7 levels (97.4%). Mean length using R with two-sided p<0.05 considered significant. of stay was 5.40 +/- 4.66 days for index operations. Overall 5-year RESULTS: Of 1,870 patients, 336 met inclusion criteria. Formal revision rate was 16.5%. The most common causes of revision at PT was initiated on POD 0 for 202 patients, and POD 1 for 134 5 years were degenerative disease (50.7%), mechanical (32.2%), patients. There was no significant difference between POD 0 and and stenosis (8.0%). Revision procedure coded at index operation POD 1 groups (respectively) regarding: age (57.9 +/- 14.4 years was associated with increased risk of revision for degenerative vs 58.4 +/- 14.3 years, p=1.00), gender (45.5% male vs 52.2% disease (HR=1.59, 95% CI: 1.29-1.98, p<0.001) and mechanical male, p=0.28), insurance type (42.1% Medicare vs 44% Medicare, Proceedings 52

p=0.58), BMI (33.2 +/- 7.8 kg/m2 vs 31.7 +/- 5.8 kg/m2, p=0.23), Of those who underwent surgical intervention, 34.2% had an or discharge destination (home discharge 88.6% vs 85.1%, improvement in ASIA impairment at one year as compared to p=0.61). The difference in LOS (9.9 hours) was large enough to be 20.6% treated without surgery, indicating that surgery led to a of statistical and clinical significance (p=0.000001214) (median 2.0 [95% CI 1.4 - 2.8] times greater likelihood of improvement 65.3 hours for POD 0 PT [interquartile (IQ) range, 43.7-74.6] vs at one year. At five year follow up, surgery was associated with a 74.2 hours for POD 1 PT [IQ range 51.6-99.8]; p=0. 000001214). 2.8 times greater likelihood of improvement in ASIA impairment The difference in distribution of postoperative nights spent in the compared to those treated non-operatively. Analysis of outcome by hospital was also clinically and statistically significant between POD region of the spine demonstrated no effect of surgery on cervical 0 and POD 1 groups, respectively (p=0.002265922) (1 night stay injuries, whereas thoracic and lumbar injuries were more likely to 21.3% vs 8.3%, 2-3 night stay 56.4% vs 54.9%, 4 or more nights experience improvement with surgical intervention. 22.3% vs 36.8%). CONCLUSIONS: While the decision to undergo surgery should CONCLUSIONS: Early initiation of PT has been proposed to be individualized, in our large review of GSWSCIs, surgical facilitate discharge following lumbar spine surgery. In our study, intervention was associated with a greater likelihood of neurologic lumbar spine patients who initiated physical therapy (PT) on recovery. Specifically, patients with thoracic and lumbar GSWSCIs postoperative day (POD) 0 demonstrated clinically and statistically have a 2.5 and 1.7 times greater likelihood of improvement in significant earlier discharge than patients who initiated PT on POD ASIA impairment with surgical intervention one year after injury, 1. Given the role of LOS in quality metrics and reimbursement, respectively. it remains important for orthopedic spine surgeons to optimize FDA DEVICE/DRUG STATUS: This abstract does not discuss or postoperative LOS. A multidisciplinary approach which includes include any applicable devices or drugs. physical therapists, along with early formal postoperative PT, may facilitate discharge following lumbar spine surgery. FDA DEVICE/DRUG STATUS: This abstract does not discuss or 55. Clinical outcomes of minimally invasive posterior include any applicable devices or drugs. decompression for lumbar spinal stenosis with degenerative spondylolisthesis 1 2 54. Surgical intervention is associated with Yuto Kobayashi, MD ; Koji Tamai, MD ; Hiromitsu Toyoda, MD, PhD2; Hidetomi Terai, MD, PhD3; Masatoshi Hoshino, MD3; Akinobu improvements in ASIA impairment scale in thoracic Suzuki, MD, PhD2; Shinji Takahashi, MD2; Yusuke Hori, MD4; Hiroaki and lumbar gunshot induced spinal cord injuries Nakamura, MD, PhD4 1 2 Brian C. Goh, MD, PhD ; Brendan Striano, MD ; Alexander 1Yodogawa Christian Hospital, Osaka City, Japan; 2Osaka City 2 3 1 Crawford, MD ; Daniel G. Tobert, MD ; Harold A. Fogel, MD ; University, Osaka, Japan; 3Dept. of Orthopaedic Surgery, Osaka City 3 3 Thomas D. Cha, MD, MBA ; Joseph H. Schwab, MD ; Christopher University, Graduate School of Medicine, Osaka, Japan; 4Osaka City 3 3 M. Bono, MD ; Stuart H. Hershman, MD University Graduate School of Medicine, Osaka, Japan 1 2 Boston, MA, US; Harvard Combined Orthopaedic Residency BACKGROUND CONTEXT: Indications for surgical procedures 3 Program, Boston, MA, US; Massachusetts General Hospital, for patients with lumber spinal stenosis (LSS) and degenerative Boston, MA, US spondylolisthesis (DS) are still under investigation. Since minimally BACKGROUND CONTEXT: Spinal cord injuries (SCIs) are relatively invasive surgery does not affect most anatomical structures, common injuries that have a lasting impact on patients and preoperative DS may not negatively affect the clinical outcomes of are a significant cause of disability. Gunshot wound spinal cord minimally invasive posterior decompression. injuries (GSWSCI) are the third most common cause of SCI and PURPOSE: To compare the clinical outcomes 5 years after are increasing in proportion. Despite the severity and frequency minimally invasive posterior decompression for LSS between of these injuries, there remains a lack of conclusive evidence patients with and without DS. regarding the optimal management of patients with GSWSCIs. STUDY DESIGN/SETTING: Retrospective cohort study. PURPOSE: We aimed to better understand the impact of surgical PATIENT SAMPLE: Overall, 198 patients with LSS who underwent intervention in patients who sustained gunshot wound induced microendoscopic or microscopic decompression and were followed spinal cord injuries. up for more than 5 years postoperatively were included in the STUDY DESIGN/SETTING: Retrospective review of prospectively present study. collected data. OUTCOME MEASURES: The clinical outcomes 5 years after PATIENT SAMPLE: Patients in the National Spinal Cord Injury minimally invasive posterior decompression for LSS between Statistical Center (NSCISC) database with GSWSCIs from 1973- patients with and without DS. 2016 (n = 4,920). METHODS: Patients who showed a segmental kyphosis of > 5 OUTCOME MEASURES: The primary outcome measure was degree at the surgical level during flexion were treated with fusion defined as ASIA impairment scale at the time of presentation and surgery. However, other patients, including those with DS, were specific follow up timepoints. treated with posterior decompression. The patients were divided into METHODS: Patient demographics, clinical information, and 2 groups: the DS group included 82 patients with > 3-mm slip and outcome data were extracted from the NSCISC database. the non-DS group included 112 patients with < 3-mm slip or without Surgical intervention was defined as any procedure involving a slip. A mixed-effects model adjusted for age and sex was used to laminectomy, neural canal restoration, open reduction, spinal compare the improvements in the visual analog scale (VAS) score fusion, or internal fixation of the spine. Functional assessments for low-back pain and the Japanese Orthopaedic Association (JOA) included the American Spinal Injury Association (ASIA) Impairment score of the 2 groups. For subgroup analysis (n=53), the changes scale and ASIA Motor Index. in the preoperative physical component summary (PCS) and the RESULTS: The majority of patients with GSWSCIs were Black/ mental component summary (MCS) of Short Form-36 of the 2 groups African American (66.9%), male (88.1%), and aged 15-29 (68.0%). at 5 years after surgery were evaluated. Proceedings 53

RESULTS: There was no significant difference in the improvement 38.8 points in the non-intervention group and 44.1 points in the of preoperative low-back pain VAS score and JOA score 5 years intervention group at discharge. There was significant greater after surgery between the 2 groups. Subgroup analysis showed no improvement in follow up serum albumin level and Barthel Index significant difference between the 2 groups in the improvement of for the intervention group when compared to non-intervention preoperative PCS and MCS 5 years after surgery. group(p<0.05). CONCLUSIONS: After carefully eliminating patients with segmental CONCLUSIONS: Nutritional and pharmaceutical management of instability, DS did not affect the clinical outcomes of minimally elderly infected patients is an important factor in determining the invasive decompression surgery. outcome of surgical care. Correction of polypharmacy, such as FDA DEVICE/DRUG STATUS: This abstract does not discuss or nutritional management focusing on the gastrointestinal tract and include any applicable devices or drugs. aggressive polypharmacy management, resulted in a significant increase in serum albumin levels and a significant improvement in Barthel Index, an index of quality of life. Nutritional management 56. Clinical effectiveness of comprehensive medicine and proper use of medications are very important in the treatment in treatment of pyogenic spondylitis in the elderly of pyogenic spondylitis in the elderly, and it is desirable to improve clinical outcomes by implementing these measures in conjunction 1 2 Hidekazu Yoshizaki, NP ; Manabu Ito, MD, PhD ; Tzong-Jing Victor with orthopedic care. 3 Wang, FRCS, MBBS FDA DEVICE/DRUG STATUS: This abstract does not discuss or 1Sapporo, Japan; 2National Hospital Organization Hokkaido include any applicable devices or drugs. Medical Center, Sapporo, Japan; 3Tan Tock Seng Hospital, Singapore, Singapore BACKGROUND CONTEXT: In recent years, the number of 57. Duration of overlap during posterior only lumbar refractory spinal infections in elderly patients with diverse co- fusion does not predict patient outcomes morbidities has been increasing in Japan. In addition, elderly Ali Farooqi, BA; Neil Malhotra, MD people are prone to low nutritional status due to age-related eating disorders and changes in digestion and absorption functions. Hospital of University of Pennsylvania, Philadelphia, PA, US Malnutrition affects systemic reserve, which not only makes the BACKGROUND CONTEXT: Given the ambiguity around treatment of infections more difficult, but also affects the quality overlapping surgery, and the public demand for further research, of life of patients. In this study, we examined the clinical efficacy more studies evaluating the impact of overlapping surgery on of combining conventional orthopedic single-discipline treatment patient outcomes are warranted. with multi-disciplinary comprehensive medical treatment of PURPOSE: This study aims to evaluate the influence of increasing pyogenic spondylitis in the elderly. duration of overlap on mid- and longer-term outcomes following PURPOSE: The purpose of this study is to examine the clinical lumbar fusion. efficacy of combining conventional orthopedic single-discipline STUDY DESIGN/SETTING: This retrospective study took place at a treatment with multi-disciplinary comprehensive medical multi-hospital university health system. treatment of pyogenic spondylitis in the elderly. PATIENT SAMPLE: 1,302 adult patients undergoing overlapping STUDY DESIGN/SETTING: Serial case-control studies. surgery during single-level, posterior-only lumbar fusion were PATIENT SAMPLE: 54 patients aged 65 years and older who were included. treated for pyogenic spondylitis between 2016 and 2019. OUTCOME MEASURES: Evaluated outcomes included OUTCOME MEASURES: Serum albumin level and Barthel Index readmission, reoperation, ED visit, mortality and overall morbidity. METHODS: The patients were divided into two groups: 41 patients METHODS: Amount of overlap was calculated as a percentage managed by a single orthopedic department (non-intervention of total overlap time. Subsequently, patients were separated into group) and 13 patients managed with Combination of conventional groups with the most (top 10% of patients) and least amounts of orthopedic single-specialty treatment and comprehensive medical overlap (bottom 40% of patients). Using Coarsened Exact Matching treatment care. The Japanese Nurse Practitioner (JNP) played a (CEM), patients with the most and least amounts of overlap were central role in the comprehensive medical care, and in addition matched on demographics, then matched on both demographics to the conventional orthopedic single-discipline medical care, and attending surgeon. Univariate analysis was carried out on nutritional management focusing on enteral nutrition. In addition, the whole population, then both the demographic matched and the JNP also plays an active role in correction of polypharmacy surgeon matched cohorts. Significance for all analyses was set at a such as reduction of non-steroidal anti-inflammatory drugs p-value < 0.05. (NASIDs), opioids and benzodiazepine as these medications may RESULTS: Increasing duration of overlap was not associated be risky for the elderly when used excessively. Serum albumin level with any patient outcomes in the whole population, demographic was used for nutritional assessment and Barthel Index for quality of matched, or surgeon matched analyses. Before exact matching, life assessment, and the degree of improvement between the two patients with the most amount of overlap had a significantly higher points was calculated at admission and discharge. CCI score (p = 0.031) and a significantly shorter length of surgery RESULTS: The per capita doses of NSAIDs and opioid analgesics (p = 0.006). In the demographic matched cohort, there was also were reduced to 13% and 9% of the non-intervention group, a shorter length of surgery (p = 0.001), but no difference in CCI respectively, resulting in acetaminophen-centered analgesic score. In the surgeon matched cohort, there was no difference in control. The mean serum albumin level at admission was 2.94 g/ length of surgery or CCI score. dl in the non-intervention group and 2.62 g/dl in the intervention CONCLUSIONS: Duration of overlap does not predict adverse mid- group, but at discharge, it was 3.16 g/dl in the non-intervention or longer-term outcomes after common neurosurgical procedures. group and 3.32 g/dl in the intervention group. The mean Barthel FDA DEVICE/DRUG STATUS: This abstract does not discuss or Index at admission was 23.1 points in the non-intervention include any applicable devices or drugs. group and 18.2 points in the intervention group, but improved to Proceedings 54

58. Comparison of outcomes of primary and revision MIS microdiscectomy is a safe and as effective treatment option for patients with recurrent herniation, and can provide outcomes minimally invasive lumbar microdiscectomy equivalent to primary surgery. Avani S. Vaishnav, MBBS1; Hikari Urakawa1; Jung Mok, BS2; Evan FDA DEVICE/DRUG STATUS: This abstract does not discuss or Sheha, MD3; Steven J. McAnany, MD3; Catherine Himo Gang, include any applicable devices or drugs. MPH1; Sheeraz A. Qureshi, MD, MBA1 1Hospital for Special Surgery, New York, NY, US; 2New York, US; 3 Hospital for Special Surgery, Stamford, CT, US Thursday, July 8 BACKGROUND CONTEXT: Although revision surgery carries 2:00–3:00 p.m. a higher risk of complications due to dissection through Bone Health Considerations in Management of scarred tissue planes, minimally invasive (MIS) techniques are Spinal Disorders increasingly being utilized to avoid scar tissue from previous approaches. However, it is not currently known whether there is a difference in outcomes between primary and revision MIS lumbar 59. Effect of cage position and insertion angle in the microdiscectomy. oblique lumbar interbody fusion: A finite element PURPOSE: To compare outcomes of primary and revision MIS study lumbar microdiscectomy. Jung-Woo Hur, PhD STUDY DESIGN/SETTING: Retrospective review of prospectively Seoul, Republic of Korea collected data. PATIENT SAMPLE: Consecutive patients who underwent 1-2 level BACKGROUND CONTEXT: Oblique lateral interbody fusion MIS lumbar microdiscectomy by a single surgeon from 2017-2020. (OLIF) is considered a useful surgical option for various lumbar OUTCOME MEASURES: 1) Clinical outcomes - length of stay, degenerative diseases with favorable clinical results and few narcotic consumption, complications and reoperations. 2) Patient- complications. However, retroperitoneal prepsoas approach reported outcome measures (PROMs) – Oswestry Disability Index compels cage to be inserted more obliquely compared to direct (ODI), VAS back& leg pain, SF-12 physical (PHS) and mental health lateral transpsoas approach, where cage is inserted more vertically. (MHS) and PROMIS physical function. Moreover, the effect of cage insertion angle on postoperative cage METHODS: Outcomes of primary and revision surgery were stability and subsidence has not been fully understood yet. compared using Chi square test and Fisher’s exact test for PURPOSE: The purpose of the present study was to evaluate categorical variables, and student t-test and Mann Whitney u-test the biomechanical effect of cage position and insertion angle on for normally and non-normally distributed continuous variables postoperative stability and subsidence following oblique lateral respectively. interbody fusion using finite element (FE) model. RESULTS: 195 patients (Primary=166, Revision=29) were STUDY DESIGN/SETTING: Finite element study. included. The revision cohort was younger (42 vs 48yrs for primary, PATIENT SAMPLE: Previously validated 3-dimensional FE model of p=0.033), had a lower Charlson Comorbidity Index (0.06 vs 0.36, intact lumbar spine (L4-5) was used. p=0.006) and shorter operation time (42 vs 48mins, p=0.033). OUTCOME MEASURES: The cage and pedicle screw – vertebral There were no differences in smoking status (p=0.830), insurance body interface behavior were assigned ‘tie’ contact condition type (p=0.689), ASA class (p=0.925), post-operative narcotic to simulate complete postoperative bone union. In addition, the consumption (p=0.927) or length of stay (p=0.968). 90% of likelihood of yield of cage and the risk of the subsidence were patients in both cohorts were discharged on the day of surgery. compared and analyzed using Peak von Mises Stresses (PVMS) The only operative complication was 1 Dural tear (0.6%) and the values occurring in each type of cage and cancellous bone, only in-hospital complication was urinary retention (n=3, 1.8%), all respectively. in the primary cohort. During the follow-up period, complications METHODS: For the vertebral fusion procedures, PEEK managed non-operatively were significantly greater in the revision (E=3500MPa, v=0.3) cage (L40*W22*H12*A12, GS Medical Co., cohort [n=3(10.3%) vs n=4(2.4%) for primary, p=0.035). However, Ltd., Korea) with titanium (E=110000MPa, v=0.33) pedicle screws there was no difference in reoperations [Primary: n=12(17.2%); (Ø6.5 x 45 mm, GS Medical Co., Ltd., Korea) were used. 6 surgical Revision: n=3(10.3%); p=0.472]. Reasons for reoperation models were created according to cage positioning and insertion were- Primary cohort: recurrent disc herniation (n=10), epidural angles (Type A: anterior 1/3, Type B: center, Type C: posterior 1/3, abscess (n=1) and unknown (n=1); Revision cohort: recurrent disc Type D: anterior 25°, Type E: Center 25°, Type F: Posterior 25°) herniation (n=1), epidural abscess (n=1), pseudomeningocele 10Nm pure moment of flexion/extension, lateral bending and axial (n=1). Both groups showed significant improvement in all rotation was applied at the superior surface of L4 endplate with a PROMs at the early follow-up (2-12 weeks) and at last follow-up compressive follower load of 400N. (p<0.0001), with no differences between groups at any timepoint. RESULTS: All 6 models showed lower stress values as compared There was no significant difference in the achievement of MCID to the yield strength of PEEK (75Mpa). 0° models demonstrated (Primary vs revision: 2 weeks 50 vs 55.2%, p=0.606; 90 days 62.7 (Types A, B and C) significantly lower likelihood of cage yield vs 65.5%, p=0.774; last follow-up 68.7 vs 65.5%, p=0.733). compared to 25° models (Type D, E and F ; 33%, 33% and 30% CONCLUSIONS: Patients undergoing revision surgery were vs 49%, 47% and 33%, respectively), suggesting anteriorly younger, had lower comorbidity burden and slightly shorter positioned cage with less insertion angle is more stable. Similarly, operative times. There was no difference in narcotic consumption, in investigating the risk of subsidence, the stresses recorded length of stay, or intra-operative and in-hospital complications. in the cancellous bone for all 6 models were less than the Although the revision cohort had a higher rate of complications reported yield strength of the cancellous bone (16.3Mpa). 0° managed non-operatively, there was no difference in reoperation models demonstrated (Types A, B and C) significantly lower risk rates. Both groups showed significant improvement in PROMs, with of subsidence compared to 25° models (40%, 57% and 40% no difference between groups. These findings suggest that revision vs 68%, 54% and 67.6%, respectively), suggesting anterior or Proceedings 55

posterior positioned cage with less insertion angle lowers the risk of Anterior and Middle (p<0.001), with no difference between Anterior subsidence. and Middle (p>0.05). CONCLUSIONS: Our study demonstrated that during OLIF, CONCLUSIONS: Although BMD at L1-L2 is often used as a marker insertion of cage more anteriorly with less insertion angle provided of lumbosacral BMD, it may overestimate BMD of other levels. better stability and less chance of subsidence. This study suggests Furthermore, all levels demonstrated differences among various that cage should be inserted more anteriorly and vertically during regions. These findings suggests the need for more detailed BMD OLIF procedure to maintain postoperative stability and to reduce estimation, especially in patients undergoing spinal instrumentation cage subsidence. in whom variations in local BMD can be used to guide surgical FDA DEVICE/DRUG STATUS: This abstract does not discuss or planning and could potentially impact clinical outcomes. include any applicable devices or drugs. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.

60. Variation of bone mineral density in the lumbar spine 61. Effect of postmenopausal state on distribution of Avani S. Vaishnav, MBBS1; Philip Louie, MD2; Chirag Chaudhary, bone mineral density in the lumbar spine MS, MBBS1; Michael H. McCarthy, MD, MPH3; Ryan Lee, MBA1; Avani S. Vaishnav, MBBS1; Philip Louie, MD2; Chirag Chaudhary, Yoshihiro Katsuura, MD1; Catherine Himo Gang, MPH1; Sheeraz A. MS, MBBS1; Michael H. McCarthy, MD, MPH3; Ryan Lee, MBA1; Qureshi, MD, MBA1 Yoshihiro Katsuura, MD1; Catherine Himo Gang, MPH1; Sheeraz A. 1 1Hospital for Special Surgery, New York, NY, US; 2Seattle, WA, US; Qureshi, MD, MBA 3Indiana Spine Group, Carmel, IN, US 1Hospital for Special Surgery, New York, NY, US; 2Seattle, WA, US; 3 BACKGROUND CONTEXT: Hounsfield units (HU), typically Indiana Spine Group, Carmel, IN, US measured at L1-L2, have been identified as a surrogate marker for BACKGROUND CONTEXT: Hounsfield units (HU), typically lumbar Bone Mineral Density (BMD). However, concern remains measured at L1-L2, have been identified as a surrogate marker for that L1-L2 BMD may not fully capture BMD differences throughout lumbar Bone Mineral Density (BMD). However, concern remains the lumbosacral spine and inadvertently provide inaccurate that L1-L2 BMD may not fully capture BMD differences throughout assessment. the lumbosacral spine and inadvertently provide inaccurate PURPOSE: To evaluate the impact of age, gender and BMI on assessment. lumbar HU, compare the conventional L1-L2 HU measurements PURPOSE: To evaluate the impact of how conventional HU with the common levels of degenerative pathology, compare HU evaluation relates to local HU at commonly instrumented levels, measurements among different vertebral levels and evaluate the and to evaluate the impact of age and post-menopausal state on distribution of HU within the individual vertebral bodies. HU in the lumbar spine. STUDY DESIGN/SETTING: Cross sectional study. STUDY DESIGN/SETTING: Cross sectional study. PATIENT SAMPLE: Consecutive patients presenting to a spine PATIENT SAMPLE: Consecutive female patients presenting to a clinic between Apr’17 and Jan’2019 who underwent lumbar CT spine clinic between Apr’17 and Jan’2019 who underwent lumbar were selected. Patients with previous lumbar surgery, tumor, CT were selected. Previous lumbar surgery, tumor, fracture or fracture or infection were excluded. infection were excluded. OUTCOME MEASURES: HU measurements performed in 7 OUTCOME MEASURES: Hounsfield Units (HU) were assessed on regions of each vertebral body: 1) Mid-sagittal, 2) Axial – Superior, lumbar CT by placing an elliptical region of interest confined to the 3) Axial – Waist, 4) Axial – Inferior, 5) Axial at the waist – Anterior, medullary space of the vertebral body, and avoiding cortical bone 6) Axial at the waist – Middle, 7) Axial at the waist – Posterior. or sclerosis. HU measurements were performed for L1-S1 in 7 METHODS: Association of HU in each region with age and BMI regions of each vertebral body: 1) Mid-sagittal, 2) Axial – Superior, was evaluated using Pearson product-moment correlation. The 3) Axial – Waist, 4) Axial – Inferior, 5) Axial at the waist – Anterior, difference in HU in each region between L1-L2 and L4 and L5 HU 6) Axial at the waist – Middle, 7) Axial at the waist – Posterior. was assessed. Comparison of HU amongst levels and amongst METHODS: Patients were divided into two groups based on different regions in each level was performed using ANOVA and whether they were pre- or post-menopausal. HU were compared paired t-tests, with post-hoc pairwise comparisons. between the pre- and post-menopausal cohorts using student t-test RESULTS: 100 patients (mean age=56yrs, BMI=26.4 kg/m2, 48% or Manny-Whitney u-test. The difference between routinely used males) were included. Age showed a negative correlation with HU L1L2 average HU and local HU in each region was calculated for in all regions at all levels (p<0.0001). BMI and gender did not show each group and compared between groups. Association of age and an association with HU. Conventional L1-L2 HU overestimated L4 menopausal state with HU was assessed using regression analyses. and L5 HU by at least 10 units in 32–67% of patients, depending RESULTS: Forty-eight patients, 18 pre-menopausal and 30 on the region. S1 demonstrated higher HU than L3 (p=0.025) post-menopausal were included. The post-menopausal group and L4 (p=0.029) in the mid-sagittal plane, and higher HU than was significantly older (67 versus 41 years; p<0.0001). Post- all other levels in the Superior (p<0.0001) and Waist [overall menopausal women had lower HU in all regions at all levels (p<0.0001), and anterior (p<0.0001), middle (p<0.0001) and (p<0.05), with the mean difference ranging from 45 to 90 HU. posterior (p<0.0001 to p=0.016)] regions in the axial plane, with Depending on the region, the L1L2 average was more than 10 units no other between-level differences. From L1 to L4, HU in the greater than L4 in 30–70% of pre-menopausal and 40–70% of Superior region was significantly lower than that in the Inferior post-menopausal women (p>0.05). L1L2 average was also more region (p<0.0001 to p=0.003). The opposite was seen at S1, with than 10 units greater than L5 measurements in 17–78% of pre- a decrease in HU from Superior to Waist to Inferior (p<0.0001). menopausal and 40–70% of post-menopausal women (p>0.05, At all levels, HU was lower in the Posterior region compared to the except Sagittal region p=0.038). Age, but not BMI showed a significant negative correlation with HU, which was strong in pre- Proceedings 56

menopausal and moderate in post-menopausal women. Age and CONCLUSIONS: Vertebral body lavage prior to cement menopausal state account for 35-60% of the variability in HU, augmentation is a safe technique to reduce cement leakage in except in the Posterior region, where they account for 25-45%. a clinical setting and has the potential to prevent pulmonary fat CONCLUSIONS: Age and post-menopausal state were embolism. Moreover, a better filling pattern can be achieved. negatively associated with HU in the lumbosacral spine, and the FDA DEVICE/DRUG STATUS: This abstract does not discuss or conventionally used L1L2 average did not adequately capture local include any applicable devices or drugs. HU variations. Local BMD assessment using HU may provide a more accurate assessment of morphometric characteristics and trabecular milieu in the operative region. 63. Does preoperative bone mineral density impact FDA DEVICE/DRUG STATUS: This abstract does not discuss or fusion success in anterior cervical spine surgery? A include any applicable devices or drugs. prospective cohort study Jad Bou Monsef, MD1; Zachariah Pinter, MD2; Arjun S. Sebastian, 2 2 2 62. Irrigation with saline solution before the MD, MSc ; Brett A. Freedman, MD ; Bradford L. Currier, MD ; Benjamin D. Elder, MD, PhD2; Ahmad N. Nassr, MD3 application of VTP bone cement in cases of balloon kyphoplasty 1SUNY Downstate, Brooklyn, NY, US; 2Mayo Clinic, Rochester, MN, US; 3Mayo Clinic/Dept of Orthopedic Surgery, Rochester, Vladimir P. Stavrev, MD, PhD, MSc MN, US Medical University, Plovdiv-Bulgaria, Plovdiv, Bulgaria BACKGROUND CONTEXT: Patients with osteoporosis have an BACKGROUND CONTEXT: Ballon Kyphoplasy is a commonly imbalance in anabolic versus catabolic bone homeostasis. It used procedure for osteoporotic fractures of the spine and some has been theorized that osteoporosis may impact fusion rates methastatic lesions. We present our 5 year experience with an in lumbar spine surgery. However to our knowledge this has not improvement of the original technique leading to better outcome. been investigated in cervical spine surgery. As our population PURPOSE: Our aim was to prove the advantages of the irrigation ages, we are encountering ever increasing numbers of patients with 0.9% saline solution of the vertebral body before the with osteoporosis and osteopenia coming in for elective surgery. application of vertebroplasty bone cement when performing PURPOSE: The purpose of this study is to identify risk factors for balloon kyphoplasty procedure. We assessed the cement leakage pseudoarthrosis in patients undergoing anterior cervical spine rate and the filling pattern in patients treated with balloon surgery. kyphoplasty with and without a newly developed lavage technique. STUDY DESIGN/SETTING: This was a prospective, single-center STUDY DESIGN/SETTING: Retrospective clinical case-control study conducted at an academic medical center between 2002 study. and 2018. PATIENT SAMPLE: A newly developed bipedicular lavage PATIENT SAMPLE: 79 patients who underwent 1-4 level anterior technique prior to cement application was applied in 64 patients cervical spine fusions between the years of 2002-2018, and had (45.1 %) with 116 vertebrae, ("lavage" group). A conventional a bone mineral density examination performed preoperatively, bipedicular cement injection technique was used in 78 patients completed the study with one year of clinical and radiographic (54.9 %) with 99 levels ("controls"). The outcome measures were follow-up. filling patterns and leakage rates. OUTCOME MEASURES: Bone density as measured by T-score, OUTCOME MEASURES: We analyzed our results for a five-year Hounsfield units, and fusion status were measured. period (2014 – 2019) in two groups of patients who underwent METHODS: We prospectively collected and analyzed data on balloon kyphoplasty in our institution for osteoporotic vertebral patients undergoing anterior cervical spine fusions involving fractures in the thoracolumbar region of the spine. In the first group between 1-4 levels between the years of 2002-2018 in which a (29 patients) we injected the VTP bone cement without irrigation of bone mineral density (BMD) examination was clinically indicated. the vertebral body with 0.9% saline solution. In the second group Based on the World Health Organization (WHO) classification (31 patients) we applied the VTP bone cement after lavage of the using DEXA scan for measurement of BMD, normal bone density vertebral body with 20 cc of 0.9% saline solution. was defined as T-score greater than or equal to -1 SD, osteopenia METHODS: We analyzed our results using control AP and lateral as having a T-score less than -1 and greater than -2.5 SD, and X-Rays immediately after surgery, then 3 months, 6 months, 9 osteoporosis as having a T-score less than or equal to -2.5 months and 1 year after surgery. On the control X-Rays we looked SD. Patients were followed for a minimum of 1 year. CT scans for radiolucent lines around the bone cement, adjacent level performed postoperatively were used to evaluate fusion. Three fractures, eventual leakage of the cement in the vertebral canal or Hounsfield unit measurements were obtained on the vertebrae elsewhere. above and below the fusion levels and averaged. A total of RESULTS: The overall leakage rate (venous, cortical defect, 79 patients completed the study with one year of clinical and intradiscal) was 37.9 % in the lavage and 83.8 % in the control radiographic follow up. BMD, number of levels fused, smoking group (p < 0.001). Venous leakage (lavage 12.9 % vs. controls status, age, sex, and ACE inhibitors/ARBs were analyzed to assess 31.3 %; p = 0.001) and cortical defect leakage (lavage 17.2 % vs. their impact on fusion success. Fusion was established when controls 63.3 %; p < 0.001) were significantly lower in the lavage there was continuous bone bridging between the vertebrae on CT group compared to "controls," whereas intradiscal leakages were scan. Multivariate analysis was performed to identify potential similar in both groups (lavage 12.1 % vs. controls 15.2 %; p = 0.51). risk factors for pseudoarthrosis utilizing JMP 10.0.0 statistical For venous leakage multivariate logistic regression analysis showed software. (SAS Institute Inc, Carey, North Carolina). lavage to be the only independent predictor. Lavage was associated RESULTS: Fourteen patients (18%) developed pseudoarthrosis with 0.33-times (95 % CI 0.16-0.65; p = 0.001) lower likelihood for at one year postoperatively. The mean age at surgery was 58.8 leakage in compared to controls. ±10.5 (30 to 84 years). The mean BMD was -0.45 ±1.4 (-3 to 4) (Table 1). Osteopenia and osteoporosis were identified as risk Proceedings 57

factors for pseudorarthorsis at a minimum of 1 year follow up (Table strength between Osteoporotic VCF cohort versus Excluded cohort 2). Number of levels fused, smoking status, Hounsfield units, ACE/ and pathological bone biopsy findings. ARB medications, age or gender were not statistically significant RESULTS: Out of 99 biopsies in the Osteoporotic VCF cohort only risk factors correlated with development of pseudoarthrosis one biopsy revealed an unsuspected malignancy (1.16%), Multiple although the study may have been underpowered to detect these Myeloma. Clinical or imaging based suspicion of malignancy was differences. found to be 91.7% sensitive and 84.2% specific. CONCLUSIONS: This study suggests that preoperative osteopenia CONCLUSIONS: Routine bone biopsy during vertebral or osteoporosis may be correlated with a higher incidence of augmentation procedure is a safe option for evaluating the cause pseudoarthrosis in anterior cervical spine surgery, even more so of the VCF but bears financially upon the health system. The than smoking or number of levels fused. While the number of cost of diagnosing a single case of unsuspected malignancy in patients enrolled in this study is small, the results are convincing our study was 31,000$. The most common pathology found was enough to warrant screening and treatment of osteoporosis as Multiple Myeloma, a chronic disease, and we could not find a study well as the optimization of preoperative bone stock in all potential that showed the benefits of early diagnosis. Looking at clinical candidates for cervical spine fusion. suspicion, previous history of malignancy was warranted only in FDA DEVICE/DRUG STATUS: This abstract does not discuss or 40.7% of VCF patients while imaging based suspicion was 100% include any applicable devices or drugs. accurate in predicting malignancy. Lack of previous malignancy and benign imaging findings were 91.67% sensitive and 84.16% specific. This study reassures spine surgeons in their ability to 64. Cost benefit analysis of routine bone biopsy diagnose malignant VCFs and does not show financial benefits in during osteoporotic vertebral compression fractures taking routine bone biopsies during VCF augmentation. augmentation procedures FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. Raphael Lotan, MD E. Wolfson Medical Center, Holon, Israel BACKGROUND CONTEXT: Vertebroplasty (VP) and Balloon 65. Bone health optimization improves osteoporosis Kyphoplasty (BKP) are viable treatment option of Osteoporotic screening and treatment prior to thoracolumbar Vertebral Compression Fractures (VCF). Metastases are another fusion possible underlying cause of VCF. At some medical institutes James T. Bernatz, MD1; Alec Winzenried, MD2; Anthony L. Mikula, a routine bone biopsy is obtainedat every VCF surgery and the MD3; Seth K. Williams, MD4; Neil Binkley, MD4; Paul A. Anderson, incidence of unsuspected neoplasm was reported as 0.7-7.3%. MD5 The published cohorts are relatively small and do not deal with 1 2 cost-benefit of a routine bone biopsy. Madison, WI, US; University of Wisconsin Hospitals and Clinics, 3 4 PURPOSE: The goal of this study is to determine the rate of Madison, WI, US; Mayo Clinic, Rochester, MN, US; University 5 unexpected malignancy in routine bone biopsies during VCF of Wisconsin, Madison, WI, US; Univ of Wisc Orthopedics & augmentation procedures and perform a cost-benefit analysis of Rehabilitation, Madison, WI, US routine bone biopsy practice. BACKGROUND CONTEXT: Osteoporosis is not rare in STUDY DESIGN/SETTING: The study is a retrospective multicenter thoracolumbar spine fusion patients and may portend poorer study, including 4 centers during 2008 to 2016. Inclusion criteria surgical outcomes. Implementation of a bone health optimization included patients solder than 60 years that presented with clinical (BHO) clinic improves osteoporosis screening and treatment symptoms and radiographic features suggesting an osteoporotic in the total joint arthroplasty population. We hypothesize that thoracic/lumbar spine compression fracture that did not respond preoperative osteoporosis is common, under-recognized and to conservative treatment (bed rest, analgesics, bracing). Exclusion undertreated in thoracolumbar fusion patients and that a BHO criteria included active malignancy or previous history of malignancy, clinic will increase preoperative osteoporosis screening rates and patients that had a pre-operative suspicion of malignancy, VCFs that pharmacologic osteoporosis treatment in this population. had suspicious fracture characteristics, active infection or imaging PURPOSE: The purpose of the study is to determine the proportion based suspicion of osteomyelitis or discitis of patients receiving appropriate osteoporosis screening and PATIENT SAMPLE: Study's population include all the patients treatment before and after initiation of a BHO clinic. that underwent BKP or VP procedures performed by a spine STUDY DESIGN/SETTING: Retrospective case series surgeon between the years 2008 – 2016. During study period one PATIENT SAMPLE: Adults age 30+ who underwent elective hundred thirty-two vertebral biopsies were performed routinely thoracolumbar spine fusion at a single tertiary care center prior to on 116 patients in 3 medical centers. 23 patients had a history of and after creation of a BHO referral clinic malignancy (26 biopsies) and 4 patients were suspected of having OUTCOME MEASURES: Osteoporosis screening rates (i.e. dual- vertebral malignancy based on imaging findings. Three of the energy x-ray absorptiometry (DXA) testing) biopsies performed did not yield enough tissue for evaluation. The METHODS: Preoperative osteoporosis risk factors, prior DXA remaining 86 patients (99 biopsies) were considered as suffering testing, and prior osteoporosis pharmacotherapy were collected osteoporotic VCF. from the electronic medical record. Fracture risk was estimated OUTCOME MEASURES: Outcome measure included history of using the Fracture Risk Assessment Tool (FRAX) with and without previous malignancy, preoperative radiological characteristics of bone mineral density (BMD) and the U.S. National Osteoporosis malignancy and final pathology results. Foundation (NOF) criteria for screening and treatment were METHODS: Statistical analysis included Paired T Test for age applied. differences between excluded patients and study’s cohort, Chi RESULTS: Ninety patients were included in the pre-BHO group; Square test for categorical variables (gender and incidence of fifty-three met criteria for BMD measurement but only 10 were malignancy) and Logistic Regression modelling to ascertain tested within two years pre-operatively. Sixteen (18%) met criteria Proceedings 58

for osteoporosis pharmacotherapy but only five of the 16 (31%) significant correlation with an increase in SS. received osteoporosis medication within six months of surgery. FDA DEVICE/DRUG STATUS: This abstract does not discuss or There were 87 patients in the post-BHO group and 19 were include any applicable devices or drugs. referred to the BHO clinic. BMD measurement was performed in 17 (89%) of patients referred to BHO clinic compared to 10% for those not referred. All patients (n=7) referred to the BHO clinic P2. Prospective randomized comparative study to meeting treatment criteria received treatment within 6 months investigate the role of intraoperative blood pressure before surgery whereas only 25% of patients not referred received on functional outcomes in operated cases of cervical treatment. spondylotic myelopathy CONCLUSIONS: Osteoporosis is not rare in adults undergoing thoracolumbar spine fusion with ~13-18% meeting criteria for Ayush Sharma Sr, MS, DNB pharmacotherapy. Pre-operative BHO referral increases screening B.R. Ambadkar Central Railway Hospital, Mumbia, Maharastra, and treatment. India FDA DEVICE/DRUG STATUS: This abstract does not discuss or BACKGROUND CONTEXT: Cervical spondylotic myelopathy (CSM) include any applicable devices or drugs. refers to signs and symptoms of compression of the spinal cord in the cervical spine either due to static or dynamic causes or more commonly as a result of a combination of both. Though a number ePosters: Basic Science/Biologics of variables exist, which determine the prognosis post-surgery, the role of intra-operative blood pressure has not been analyzed much P1. Evaluation of spinopelvic parameters in lumbar in current literature. The practice of elevating MAP, post spinal cord prolapsed intervertebral disc injury (SCI), is widely practiced and also forms a recommendation Ghanshyam Kakadiya, MS, MBBS of AANS/CNS Joint Committee Guidelines. This led us to investigate the role an elevated MAP has to play during surgery for CSM, in Department of Spine Surgery, Mohali, Panjab, India order to optimize outcomes and minimize complications. BACKGROUND CONTEXT: Spinopelvic morphology and PURPOSE: Comparison of the clinical and radiological outcome in orientation are usually described in terms of pelvic incidence two groups of 30 patients each who underwent surgeries for CSM, (PI), pelvic tilt (PT), and sacral slope (SS). The orientation and in which one group of 30 patients had intra-operative MAP in the morphology of the pelvis can affect degenerative changes in the normal range and other group of 30 patients had raised MAP intra- lumbar spine. Thus, here we investigated the relationships between operatively. various sagittal spinopelvic parameters and the degree of disc STUDY DESIGN/SETTING: This prospective randomized degeneration in young adults. comparative pilot study was conducted at a tertiary care spine PURPOSE: The study purpose was to investigate the relationships centre at Mumbai over 18 months from November 2018 to June between various sagittal spinopelvic parameters and the degree of 2020. IRB approval was taken prior to commencement. A total disc degeneration in young adults. of 84 patients were enrolled in the study as per the Inclusion and STUDY DESIGN/SETTING: A cross-sectional study. Exclusion criteria (Table 1). PATIENT SAMPLE: 180. Table 1: Inclusion and Exclusion criteria for the enrolment of the OUTCOME MEASURES: Various spinopelvic parameters were patients for the study assessed from the scannogram using the software. METHODS: A hospital-based cross-sectional study with a total of 180 cases was done. Patients presenting with back or leg pain having prolapsed disc on magnetic resonance imaging (MRI) were INCLUSION CRITERIA EXCLUSION CRITERIA included in the study. A standing radiograph of the lumbosacral spine from dorso-lumbar junction to mid-thigh was taken. Various spinopelvic parameters were assessed from the scannogram using the software. Clinical & radiological diagnosis of cervical RESULTS: The mean age was 39.27 years. L5S1 was the most Traumatic myelopathy common level. Mean SS, PT, PI, and LL were 37.78°, 13.52°, spondylotic myelopathy 51.33°, and 41.01°. Disc pathologies at L1L2, L2L3, and L4L5 level C1 to C7 levels showed a positive correlation with PT, PI, and LL. Disc pathology at the L5S1 level shows a positive correlation with PT and LL. A statistically significant correlation between SS and degenerative Maximum of 6 levels Preoperatively hypertensive spondylolisthesis at L4L5 was found from data with P = 0.023. affected patients Discussion: An increase in SS statistically significantly increases the chance of development of degenerative spondylolisthesis at Patients in which intraoperative Age > 20 years and < 80 year L4L5. An increase in PT, PI, and LL will cause an increase in disc BP is not able to be maintained pathology at L1L2. An increase in SS, PT, PI, and LL will cause an increase in disc pathology at L2L3. An increase in SS, PT, PI, and LL will cause an increase in disc pathology at L4L5. An increase in PT PATIENT SAMPLE: 84 patients, fulfilling the selection criteria were and LL will cause an increase in disc pathology at L5S1. randomly divided into two groups by asking the patients to pick up CONCLUSIONS: Standing lateral view radiograph from dorso- slips from a bowl. One group was named “NORMOTENSIVE” that lumbar junction to the mid-thigh is as good as standing whole had intraoperative mean arterial pressure in the normal range. spine radiograph for measurement of spinopelvic parameters. The normal range of MAP was drawn by the mean of 5 blood Degenerative spondylolisthesis at L4L5 has a statistically pressure readings, of which the first two were taken 2 weeks and Proceedings 59

1 week preoperatively and the remaining three were taken over two groups the improvement in MJOA scores were better for the 3 consecutive days immediately preoperatively at least 24 hours hypertensive group during the one-year follow-up although this before the surgery. The other group was named “HYPERTENSIVE” difference was statistically not significant. Similarly, improvement had intra-operative BP 20 mm of Hg higher than the preoperative in VAS scores were comparable between the two groups but at average MAP with the variation of +5 mm Hg. The preoperative one-year follow-up the VAS score of hypertensive groups was and intra-operative blood pressure recording was done by digital significantly lower compared to the normotensive group(p=0.02). sphygmomanometer. In our study, the ISI grade improved to Grade 1 in 66.7 % of the OUTCOME MEASURES: The outcomes were recorded, evaluated patients in both the groups from a preoperative ISI grade of 2 or 3 in and followed up by an independent observer at immediate 60% of the patients in the hypertensive group and 56.7% patients postoperative period, 3 months, 6 months and 1 year by the with ISI Grade 1 in the normotensive group. mJOA, visual analogue score (VAS) and American spine injuries CONCLUSIONS: Based on the study of the effect of intraoperative association impairment scale (ASIA) score. MAP on functional outcome of patients operated for CSM, we METHODS: The data was entered in Microsoft excel and analyzed conclude that MAP intra-operatively should be individualized using SPSS version 20.0. The qualitative data was analyzed using according to preoperative average blood pressure assessment tables and bar diagrams. The quantitative data was expressed of the patient. Keeping intraoperative MAP at higher level as mean and standard deviation. The association between two (preoperative MAP + 20 mm Hg) during surgery for CSM, can result variables was done with chi-square test. Comparison of mean in better neurological improvement. between two groups was done with unpaired t-test and comparison FDA DEVICE/DRUG STATUS: This abstract does not discuss or of mean values at different time intervals was done with repeated include any applicable devices or drugs. measures ANOVA and multiple comparison within groups was done with Sidak test. A p-value less than 0.05 was considered statistically significant. ePosters: Diagnostics/Imaging RESULTS: In our study the mean age in hypertensive group was 53.97 ± 12.31 years while in the normotensive group it was P3. Telemedicine visits generate accurate surgical 56.93 ± 8.76 years, with most of the cases in both the groups plans in spine surgery >60 years (40.0%) of age reflecting the degenerative nature of the pathology. There was no significant statistical difference in Alexander Crawford, MD1; Harry M. Lightsey IV , MD2; Grace Xiong, terms of age and gender distribution between the two groups. MD2; Brendan Striano, MD1; Andrew J. Schoenfeld, MD3; Andrew With respect to the mode of presentation, 36.7% presented with Simpson, MD4 signs and symptoms of myelopathy alone and 63.3% presented 1Harvard Combined Orthopaedic Residency Program, Boston, MA, with signs and symptoms of myelopathy and radiculopathy in US; 2Boston, MA, US; 3Brigham and Women's Hospital, Boston, the hypertensive group while in the normotensive group it was MA, US; 4Brigham and Women's Hospital, Dept of Orthopedic 40.0% and 60.0% respectively. In our study, OPLL on CT scan was Surgery, Boston, MA, US present in 30% cases in the hypertensive group and 26.7 % in the normotensive group. The most effected levels affected in both the BACKGROUND CONTEXT: The role of telemedicine is rapidly groups were C3-C6. The mean duration of symptoms in months evolving in all medical specialties, including orthopaedic spine till surgery in the hypertensive group was 9.23 ± 2.56 months, surgery. In particular, the utility of telemedicine to identify while in the normotensive group, it was 5.96 ± 2.98 months, and operative candidates and to determine surgical plans has yet to be this was statistically significant (p=0.0035). The preoperative demonstrated. MAP in the hypertensive group was 89.57 ± 9.05 mm Hg and in PURPOSE: The aims of this study were: 1. To assess whether the normotensive group it was 91.93 ± 9.93 mm Hg which was surgical plans proposed following telemedicine visits changed statistically not significant. The intra operative mean arterial after subsequent in-person evaluation and 2. To characterize the blood pressure in hypertensive group was 108.20 ± 8.48 mm Hg extent and types of virtual exams performed across providers at two and in the normotensive group it was 94.90 ± 8.21 mm Hg and tertiary care centers. this difference was statistically significant. On comparing the two STUDY DESIGN/SETTING: Retrospective cohort study. groups, there was no statistical difference in intraoperative blood PATIENT SAMPLE: The clinical registry of Mass General Brigham loss and postoperative stay between the two groups. Neurological (MGB) was used to review all telemedicine encounters within the improvement was documented in 19/30 (63.3%) patients of Division of Orthopaedic Spine Surgery between March 1, 2020 hypertensive group compared to 16/30 (53.3%) patients of and July 31, 2020 and to identify patients who were indicated for normotensive group, while 10 patients of each group remained elective surgery during their virtual visit. neurologically unchanged at one-year follow-up. The best recovery OUTCOME MEASURES: Patient age, biologic sex, race/ethnicity, was seen in patients presenting with a symptom duration less indication for visit, orthopaedic subspecialty service, indication for than 3 months, irrespective of the group. With respect to the surgery, the extent of the virtual physical examination, and pre- complications, one patient in both the groups had a transitional operative surgical plan were recorded. postoperative C5 weakness; whereas in the hypertensive group, METHODS: The clinical registry of Mass General Brigham (MGB) a postoperative dural leak was encountered which was managed was used to identify patients who were indicated for elective conservatively. Comparison of VAS and mJOA scores at various surgery during their virtual visit. The surgical plans delineated time intervals among the cases was done with All Pairwise Multiple during the telemedicine encounter were then compared to final Comparison Procedures. There was statistically significant pre-operative plans as documented following subsequent in-person improvement noted with comparison pairs of preoperative vs evaluation. Virtual physical exams were categorized based on the immediate postoperative, preoperative vs. 6 months, preoperative extent of maneuvers performed and assigned a value ranging from vs.1 year, postoperative vs. 6 months, postoperative vs. 1 year for 0, no exam, to 3, three or more maneuvers performed. both the groups. On comparing the MJOA scores between the RESULTS: In total, 1,601 virtual visits were abstracted in full. 59 Proceedings 60

patients were indicated for surgery with a detailed surgical plan procedure during cage installment and screw insertion. We based on virtual visit alone. In 55 of these 59 patients (proportion calculated the percent deviation from the epidural area (mm2) 0.08, 95% CI 0.03 to 0.19) the surgical plan did not change before and after surgery as well as the slip distance (mm) and after in-person evaluation. Inter- and intra-provider virtual exam disc space distraction (mm) and their differences before and after variability was evident both within and across MGB institutions. surgery to statistically examine the correlations between each of CONCLUSIONS: There is much work to be done to determine these parameters. how to best leverage the synergies between telemedicine and RESULTS: The epidural area was 48.5±18.5 mm2 before surgery in person evaluation for orthopaedic spine patients. Here, we and 81.9±42.2 mm2 after surgery, with a percent deviation of have demonstrated the capability of telemedicine to support the 60.1±47.4%. The slip distance was 7.1±4.2 mm before surgery development of accurate surgical plans across two institutions. and 1.0±2.1 mm after surgery, with a difference of 6.3±3.2 mm. Furthermore, this work highlights the substantial variability in The disc distraction was 5.1±2.6 mm before surgery and 8.6±1.1 the utilization of physical examination maneuvers conducted via mm after surgery, with a difference of 3.3±2.3 mm. The correlation telemedicine across institutions and providers. coefficient between the epidural deviation and the difference in FDA DEVICE/DRUG STATUS: This abstract does not discuss or slip distance, as well as that between epidural deviation and the include any applicable devices or drugs. difference in disc space distraction, were 0.54 (p<0.01) and 0.56 (p<0.01), respectively, thereby showing significant correlations. Furthermore, there was also a significant correlation of 0.47 P4. How does distraction of the disc space with (p<0.05) between the differences in slip distance and disc space lateral lumbar interbody fusion provide correction of distraction. degenerative spondylolisthesis? CONCLUSIONS: Distraction of the disc space in LLIF led to significant improvement in degenerative spondylolisthesis. The 1 2 Shuntaro Wada ; Hideki Murakami, MD, PhD ; Hirooki Endo, MD, ligamentotaxis effect not only improved spinal disc protrusion 3 4 4 PhD ; Daisuke Yamabe, MD, PhD ; Yusuke Chiba, MD ; Ryosuke and tucking of the yellow ligament but also provided localized 4 5 Oikawa, MD ; Minoru Doita, MD correction of degenerative spondylolisthesis. Therefore, this 1Iwate Medical University Orthopedic Surgery, Iwate Prefecture surgical technique provided sufficient indirect decompression. Yahaba, Japan; 2Morioka, Iwate, Japan; 3Morioka, Japan; 4Iwate FDA DEVICE/DRUG STATUS: This abstract does not discuss or Medical University, Morioka, Japan; 5Iwate Medical University include any applicable devices or drugs. School of Medicine, Morioka, Iwate, Japan BACKGROUND CONTEXT: Recent studies have demonstrated a good indirect decompression due to the ligamentotaxis effect of ePosters: Injections/Interventions disc space distraction during lateral lumbar interbody fusion (LLIF). However, as yet, no detailed examinations have been performed on P5. Liposomal bupivacaine does not decrease the correction of degenerative spondylolisthesis resulting from the postoperative opioid use or length of hospital stay in distraction of disc space based on this effect. patients undergoing ACDF PURPOSE: This study examined the magnitude of degenerative Eric Neufeld, MD1; Terence Ng2; Ben Schaffler, 3MD ; Cesar spondylolisthesis correction and how indirect decompression was Iturriaga, DO4; Alan Job, MD5; Austen Katz, MD6; Rohit B. Verma, achieved by distraction of the disc space in LLIF. MD7 STUDY DESIGN/SETTING: None of the cases had received special corrective procedure during cage installment and screw insertion. 1Northwell Health Long Island Jewish Medical Center, Queens, We calculated the percent deviation from the epidural area (mm2) NY, US; 2Donald and Barbara School of Medicine at Hofstra/ before and after surgery as well as the slip distance (mm) and Northwell, Hempstead, NY, US; 3Mineola, NY, US; 4New Hyde Park, disc space distraction (mm) and their differences before and after NY, US; 5Northwell Health North Shore-LIJ, New Hyde Park, NY, surgery to statistically examine the correlations between each of US; 6Northwell Health Orthopedics, Long Island Jewish Hospital, these parameters. Queens, NY, US; 7University Orthopaedic Associates, Great Neck, PATIENT SAMPLE: We examined the 24 cases of patients (6 NY, US male, 18 female, mean age 67.8 years) who had undergone BACKGROUND CONTEXT: Liposomal bupivacaine (LB) is local indirect decompression and fusion (IDF) by LLIF and percutaneous anesthetic perioperatively infiltrated into the surgical site to pedicle screw for spinal canal stenosis due to degenerative promote postoperative analgesia.1 Despite its widespread use, spondylolisthesis in single interbody space more than 2 years prior. definitive data demonstrating its efficacy is limited2 especially OUTCOME MEASURES: The epidural area was 48.5±18.5 mm2 in patients undergoing anterior cervical discectomy and fusion before surgery and 81.9±42.2 mm2 after surgery, with a percent (ACDF). deviation of 60.1±47.4%. The slip distance was 7.1±4.2 mm PURPOSE: To examine whether ACDF patients who received before surgery and 1.0±2.1 mm after surgery, with a difference of preoperative LB (LB group) exhibited decreased postoperative 6.3±3.2 mm. The disc distraction was 5.1±2.6 mm before surgery opioid use and length of hospital stay (LOS) compared to ACDF and 8.6±1.1 mm after surgery, with a difference of 3.3±2.3 mm. patients who did not receive preoperative LB (controls). The correlation coefficient between the epidural deviation and STUDY DESIGN/SETTING: Retrospective chart review. the difference in slip distance, as well as that between epidural PATIENT SAMPLE: 82 patients who underwent primary ACDF (n = deviation and the difference in disc space distraction, were 82). 0.54 (p<0.01) and 0.56 (p<0.01), respectively, thereby showing OUTCOME MEASURES: Surgical complications, postoperative significant correlations. Furthermore, there was also a significant opioid use, and length of hospital stay. correlation of 0.47 (p<0.05) between the differences in slip METHODS: Eighty-two patients who underwent primary ACDF by distance and disc space distraction. a single surgeon from 2016-2019 were retrospectively identified METHODS: None of the cases had received special corrective from an institutional database. Patient demographics, medical Proceedings 61

comorbidities, Surgical complications, postoperative opioid use, PURPOSE: We present the study design and early results of and LOS were collected. Data were analyzed using independent the first randomized controlled trial utilizing the Apple Watch to t-tests, chi-square tests, and multiple linear regression. objectively monitor patients before and after elective spine surgery. RESULTS: Fifty-nine patients received preoperative LB (LB group) STUDY DESIGN/SETTING: The study is at the Stanford University while twenty-three patients did not (controls). Univariate analysis Hospital and Stanford Neuroscience Health Clinic. revealed that the LB group did not require significantly fewer PATIENT SAMPLE: Our study is enrolling English-speaking adult opioids on postoperative day (POD) 0 (p = 0.471), POD1 (p = patients undergoing elective spine surgery by six neurosurgery 0.970), POD2 (p = 0.914), throughout the entire hospital course (p attending physicians at Stanford University Hospital. = 0.845), or throughout the entire hospital course after normalizing OUTCOME MEASURES: The outcome measures of this study by LOS (p = 0.538). There was also no significant difference in LOS are the correlation between objective patient measures and between groups (p =0.833). Multivariate analysis showed that the patient-reported outcome measures, change in objective outcome number of cervical vertebrae involved in the operation significantly measures before and after surgery, patient compliance with predicted opioid use on POD0 (p = 0.005) and throughout the wearing Apple Watch and patient satisfaction with their spine care. hospital course after normalizing by LOS (p = 0.024) but LB use, METHODS: Our study is enrolling English-speaking adult patients age, and body mass index (BMI) did not. For every additional undergoing elective spine surgery by six neurosurgery attending vertebral level involved, approximately 225 additional morphine physicians at Stanford University Hospital. Patients are randomized milligram equivalents (MMEs) were utilized on POD0 while 156 to either the interventional or control groups. Interventional additional MMEs were utilized throughout the hospital course after patients receive an Apple Watch, which they are required to wear normalizing by LOS. for 2-6 weeks pre-operatively and 1 year post-operatively. They are CONCLUSIONS: ACDF patients who received preoperative LB also asked to download an application developed for this study, did not require fewer postoperative opioids or exhibit a decreased NeuroCoach. This is a HIPPA-compliant app that is available on LOS compared to controls. Patients whose procedures involved the Apple app store and collects the following activity measures: a greater number of cervical vertebrae were associated with daily steps, distance traveled, flights climbed, calories, heart rate, greater opioid use on POD0 and throughout the hospital course and heart rate variability. Objective progress reports are provided after normalizing by LOS. The results of this study suggest that to the intervention patients and their surgeons at each follow-up ACDF patients, especially those with a high number of vertebrae visit. Both intervention and control patients receive surgery and involved, may require additional or alternative analgesia to follow-up visits per the attending surgeon’s standard of care. They LB. References1. Hamilton TW, Athanassoglou V, Mellon S, et respond to the following well-validated quality of life surveys pre- al. Liposomal bupivacaine infiltration at the surgical site for the operatively and at 4-6 weeks, 3 months, 6 months, and 1 year management of postoperative pain. Cochrane Database Syst Rev. post-operatively: Oswestry Disability Index (ODI), Neck Disability 2017;2(2):CD011419.2. Puffer RC, Tou K, Winkel RE, Bydon M, Index (NDI), Visual Analog Scale (VAS), EuroQOL-5 Dimensional Currier B, Freedman BA. Liposomal bupivacaine incisional injection Questionnaire (EQ-5D), 36-Item Short Form Survey (SF-36) and in single-level lumbar spine surgery. Spine J. 2016;16(11):1305- Patient-Reported Outcome Measurement Information System 1308. (PROMIS). All patients also complete a study-specific questionnaire FDA DEVICE/DRUG STATUS: This abstract does not discuss or about their satisfaction with their surgery and understanding of include any applicable devices or drugs. their surgical recovery. Our study is approved by the Stanford IRB and actively enrolling as of Sep 1, 2020. Further details are available at spinetrak.stanford.edu and clinicaltrials.gov/ct2/show/ ePosters: Interdisciplinary Care NCT04379921. Target enrollment is 100 intervention and 100 control patients, which is powered at alpha 0.05 and power 80% to P6. SpineTrak: The first randomized control trial detect a 15% difference in ODI. using the Apple Watch to objectively track spine RESULTS: To date, we have enrolled 6 patients (n=3 intervention; n=3 control) in SpineTrake. On average, intervention participants surgical patients have worn their Apple Watch 83.3% (+/- 37.5%) of the days since Christopher Leung, BA1; Harsh Wadhwa, BS2; Parastou Fatemi3; enrollment and for 12.6 hours (+/- 4.9) per day. Atman Desai, MD4; Christy C. Tomkins-Lane, PhD5; Corinna CONCLUSIONS: To the best of our knowledge, this is the Zygourakis, MD6 first randomized control trial to assess feasibility of using a 1Stanford University School of Medicine, Department of commercially available activity monitor in spine patients before and Neurosurgery, Stanford, CA, US; 2Stanford, CA, US; 3Durham, after spine surgery. Here, we present preliminary results of early NC, US; 4Stanford Healthcare, Stanford, CA, US; 5Mount Royal participants. Our ultimate goal is to determine whether objective University, Calgary, AB, Canada; 6Stanford Dept. of Neurosurgery, measures correlate with subjective PROMs and to develop a Stanford, CA, US novel combined metric to better track spine surgical patients in real-time.1. Epstein NE. A review article on the benefits of early BACKGROUND CONTEXT: Early mobilization after surgery mobilization following spinal surgery and other medical/surgical reduces complications and is associated with improved survival, procedures. Surgical neurology international 2014;5:S66-73. decreased length of hospitalization, and improved psychological FDA DEVICE/DRUG STATUS: This abstract does not discuss or well-being [1]. However, current methods for evaluating the include any applicable devices or drugs. mobility and outcomes of spine surgery patients are limited and rely on patient-reported outcome measures (PROMs) that are subjective and may be influenced by psychiatric comorbidities and chronic pain. There are numerous commercially available wearable activity monitors, including the Apple Watch, that allow for real- time tracking of objective measures that may allow patients and surgeons to better monitor post-operative mobility and outcomes. Proceedings 62

ePosters: Manual Therapy (mean pre-VAS= 38.1±21.0). OUTCOME MEASURES: The primary outcome measure was forward head posture (FHP), assessed by measuring P7. The role of forward head posture in non-specific craniovertebral angle on profile photographs. Secondary outcome neck pain measures, included pain intensity (VAS), neck disability index Hilla Sarig Bahat, PT, MPT, PhD (NDI), and neck kinematics. Neck kineamtic measures included University of Haifa, Kerem Maharal, Israel cervical motion velocity, smoothness and acceleration/deceleration ratio, quantified using a neck virtual-reality system. BACKGROUND CONTEXT: In spite of the high prevalence METHODS: This study employed a cross-sectional design. A of neck pain and its serious effect on the quality of life, the convenience sample was recruited via targeted advertising pathophysiological mechanism has remained unclear in the to the staff and students of The University of Haifa. The study majority of patients. Additionaly, radiological studies of the cervical received ethics approval from the University of Haifa (Number spine have not been successful in correlating structural changes 15/217).Experimental procedure After assessing eligibility, all and a specific dysfunction or symptoms in neck pain. Therefore, participants were required to provide a written informed consent. the clinical guidelines recommend that once traumatic or serious They completed relevant questionnaires and were then were pathology (such as fracture or progressive disease) has been ruled photographed in their natural, comfortable posture (craniovertebral out, patients with neck pain are often diagnosed with “non-specific angle 1). The second profile photograph was taken while wearing neck pain” and are referred to what is considered the first-choice the HMD (craniovertebral angle 2, Figure 1). The kinematic VR treatment- physiotherapy. The acceptable clinical approach to assessment followed in the same sitting position, and a third photo neck pain in physiotherapy includes assessing disabilities and was taken upon completion of the VR assessment while wearing impairments and subsequent treatment directed toward the the HMD (craniovertebral angle 3). Lastly, a fourth photograph was identified functional impairments. several impairments have been taken after the HMD was removed (craniovertebral angle 4).All established to be associated with neck pain, including restricted profile photos were taken from the left side at a fixed distance (80 cervical range of motion (ROM), reduced cervical isometric cm measured from the left foot of the participant).Prior to the VR strength, and impaired kinematics. Poor posture is traditionally assessment, all participants were required to perform a warm-up associated with various musculoskeletal disorders. Consequently, consisting of two cervical movements into flexion, extension, right educators in the musculoskeletal field have long taught postural and left rotation, followed by an introductory VR session to ensure observation as part of the physical assessment. Forward head complete control of the virtual tasks. Kinematic data were collected posture (FHP) is hypothesized to be associated with neck pain; simultaneously by the software during the VR assessment, and however, unlike the well-established impairments above, evidence data reports were automatically generated at the end of each in support of this relationship between forward head posture and session. In order to standardize the procedure, the assessment neck pain remains controversial. sequence was uniform for all of the participants. The study took PURPOSE: To investigate the relationship between FHP, and neck place at the physiotherapy department lab, University of Haifa. The pain intensity, disability, and cervical kinematics in patients with whole experimental procedure took an hour approximately. All the neck pain when compared to asymptomatic individuals. participants were assessed by the same qualified physiotherapist. STUDY DESIGN/SETTING: This study employed a cross-sectional RESULTS: There were no significant differences between design. A convenience sample was recruited via targeted patients with neck pain and asymptomatic individuals in FHP advertising to the staff and students of The University of XXX. (craniovertebral angle = 48.24º±7.29; 48.90º±5.89, respectively, The study received ethics approval from the University of XXX p>0.05). The neck pain group demonstrated more restricted range (Number 15/217).The study population consisted of volunteers of motion and slower neck movements (p<0.05).We found no aged 18-65 years old, with or without neck pain. Inclusion criteria significant correlation between FHP and neck kinematics, visual to the neck pain group were self-reported persistent neck pain analog scale, and NDI. (more than 2 months), with or without referral to the upper limb, CONCLUSIONS: Our study revealed no association between and Neck Disability Index (NDI) greater than 10% (mild disability). craniovertebral angle representing FHP, and neck pain, kinematics, The control group included volunteers aged 18-65 years old that disability or pain intensity. Accordingly, findings do not support the reported no systemic diseases or spinal pain. Exclusion criteria common notion that FHP is important when assessing neck pain in for both groups were a history of cervical fracture, dislocation or individuals with self-reported, non-specific neck pain. surgery; existing vestibular pathology; current intake of drugs FDA DEVICE/DRUG STATUS: This abstract does not discuss or which may alter pain or performance; and visual and cognitive include any applicable devices or drugs. impairment that could limit the ability of individuals to follow instructions. A single physiotherapist investigator, qualified as a direct access clinician, assessed the exclusion criteria. PATIENT SAMPLE: Forty-three volunteers were recruited to the study (18 males, 25 females). One female left the neck pain group due to motion sickness during the VR session, and her data was removed from the dataset (analyzed N=42). The control group consisted of 10 females and 10 males (mean age= 33.6±7.7 years), and the neck pain group consisted of 14 females and 8 males (mean age= 38.1±9.9 years). No significant group difference was found in age (p>0.05) or in gender (chi-square likelihood ratio= 0.37, p>0.1).Participants in the neck pain group presented with chronic neck pain (mean duration= 63.4±50.2 months) and a mild neck disability (mean NDI= 20.6±10.5). Pain intensity was mild Proceedings 63

ePosters: Motion Preservation P9. Late failure of cervical disc arthroplasty due to osteolysis P8. Is there a relationship between bony fusion Scott L. Blumenthal, MD1; Daniel Kiridly, MD, MBA2; Jessica after anterior cervical discectomy and fusion Shellock, MD3; Richard D. Guyer, MD1; Jack E. Zigler, MD2; Donna and heterotopic ossification after cervical disc D. Ohnmeiss, PhD4 arthroplasty in hybrid surgery? 1Center for Disc Replacement at Texas Back Institute, Plano, TX, 2 3 Junbo He, MD US; Texas Back Institute, Plano, TX, US; Texas Back Institute, Fairview, TX, US; 4Texas Back Institute Research Foundation, Plano, West China Hospital, Sichuan University, Chengdu, Sichuan, China TX, US BACKGROUND CONTEXT: Hybrid surgery (HS) has become BACKGROUND CONTEXT: Anterior cervical discectomy and an alternative procedure for the treatment of multilevel cervical fusion (ACDF) has long been the standard of care in addressing degenerative disc disease with satisfactory outcomes. However, spondylotic pathology in the cervical spine. More recently, some adverse outcomes have recently emerged, such as total disc replacement (TDR) has emerged as a motion-sparing heterotopic ossification (HO) and anterior bone loss (ABL). alternative to ACDF in appropriately selected patients. Multiple Furthermore, HO was found mostly located in the posterior and studies have found TDR to be noninferior or superior to ACDF with lateral of the cervical intervertebral disc space. The mechanism of respect to clinical outcomes and have reported lower reoperation anterior heterotopic ossification (AHO) formation may be different, rates following TDR. However, cases of late osteolysis requiring and its relationship with ABL was uncertain. reoperation following cervical TDR have been reported, and this PURPOSE: To investigate the relationship between bony fusion phenomenon warrants further investigation. after anterior cervical discectomy and fusion (ACDF) and PURPOSE: The purpose of this study was to describe 5 patients heterotopic ossification (HO) after cervical disc arthroplasty (CDA) who developed late osteolytic reaction after cervical TDR who in hybrid surgery (HS). required reoperation. STUDY DESIGN/SETTING: Retrospective analysis. STUDY DESIGN/SETTING: Review of cases presenting to a spine PATIENT SAMPLE: Clinical data of ninety-one patients who specialty center. had undergone consecutive 2-level HS between January 2011 PATIENT SAMPLE: Five patients, 4 males and one female, who and January 2018 and with a minimum of 2-years follow-up was underwent reoperation for cervical TDR removal due to late analyzed. osteolytic reaction were included. OUTCOME MEASURES: HO was assessed based on McAfee’s OUTCOME MEASURES: Data recorded for each patient was classifications while fusion success was evaluated according the general descriptive data, clinical presentation, timing of onset of Food and Drug Administration approved criteria. Clinical outcomes symptoms following index TDR, imaging findings, intraoperative and radiographic parameters were collected and used for the findings, culture results, and clinical outcome after TDR removal relevant comparisons. and fusion. METHODS: Clinical data of ninety-one patients who had undergone METHODS: A surgery log was reviewed to identify cases of cervical consecutive 2-level HS between January 2011 and January 2018 TDR removal due to osteolysis and the data recorded. and with a minimum of 2-years follow-up was analyzed. HO was RESULTS: Five patients were identified who underwent cervical assessed based on McAfee’s classifications while fusion success TDR removal due to osteolysis. Four cases involved the M6-C was evaluated according the Food and Drug Administration prosthesis, and one involved the Prestige LP. The devices were approved criteria. Clinical outcomes and radiographic parameters removed at a mean of 37 months following index TDR, ranging from were collected and used for the relevant comparisons. 24 to 54 months. Patients generally reported good symptom relief RESULTS: HO was identified in 48.4% of patients (44/91). The after the TDR implantation, then gradually developed neck and/or fusion rates of patients in the HO group and the non-HO group at arm pain over a period of several months. In all cases, osteolysis of 3, 6, and 12 months postoperatively, and the final follow-up were the vertebral body endplates contacting the prosthesis was evident 81.8% and 19.1%, 95.4% and 74.5%, 95.4% and 85.1%, and on plain radiographs, with CT needed to evaluate the extent of 97.7% and 93.6% respectively. The fusion rates were significantly bone loss. In 4 of the 5 cases, soft tissue swelling or a soft tissue higher at 3 and 6 months after operation in the HO group than in collection was noted anterior to the prosthesis on preoperative the non-HO group (P<0.05). Patients in both groups had significant imaging. Despite the extensive bony resorption accompanying the improvements across all clinical outcomes at final follow-up. osteolysis, only one of the 5 patients required a total corpectomy CONCLUSIONS: There was a significant relationship between bony and reconstruction with a cage (patient had received a 2-level fusion and occurrence of HO after HS, suggesting that both bony Prestige LP). In the other 4 cases, ACDF with an anterior plate fusion and HO are reflections of individual osteogenic capacity. was undertaken after TDR removal. C. acnes was identified from However, a reliable predictor of postoperative bone formation is operative culture in all cases, and all patients were treated with needed in the future to guarantee a solid bony fusion after ACDF and IV antibiotics for 6 weeks. Pathology results were available for two to further take full advantage of the motion-preserving from CDA. patients, and in one case they were more consistent with acute FDA DEVICE/DRUG STATUS: This abstract does not discuss or infection, while in the other case they were more consistent with include any applicable devices or drugs. chronic wear particle-mediated inflammation. In all cases, a good clinical outcome following revision surgery was achieved, with resolution of preoperative pain and neurologic symptoms. CONCLUSIONS: These cases of late osteolysis along with others reported in the literature are concerning, and spine surgeons should be aware of the possibility of this occurrence and address it accordingly with patients. The true etiology of these late cases of post-TDR osteolysis and their impact on the overall safety of the Proceedings 64

prostheses involved remain unclear. In particular, we have not yet CONCLUSIONS: This study illustrates that obesity is associated been able to identify whether the reported cases of late osteolysis with longer operative times, longer length of stay, and increased following cervical TDR stem from infection with C. acnes causing use of postoperative opioids. gradual bony resorption, or if the primary pathology is that of an FDA DEVICE/DRUG STATUS: This abstract does not discuss or osteolytic foreign body mediated reaction to wear debris, with include any applicable devices or drugs. possible secondary colonization. Long-term follow-up studies are needed to quantify the rates of late osteolysis in different prostheses designs, and more detailed pathological analysis may P11. Comparison of opioid consumption patterns of 3 aid in differentiating infectious from wear-mediated osteolytic interbody fusion surgical techniques reactions. 1 1 FDA DEVICE/DRUG STATUS: M6-C, 1-level (Approved for this Taryn E. LeRoy, MD ; Andrew S. Moon, MD ; Marissa Gedman, BA, 2 3 1 indication), M6-C, 2-level (Not approved for this indication), MS ; Jessica P. Aidlen, MD ; Ashley L. Rogerson, MD Prestige LP, 2-level (Not approved for this indication) 1Tufts Medical Center, Boston, MA, US; 2Tufts University School of Medicine, Boston, MA, US; 3Newton-Wellesley Hospital Spine Center, Newton, MA, US ePosters: Psychosocial/Behavioral BACKGROUND CONTEXT: Back pain and spine surgery have been major drivers of opioid consumption and spine surgery has P10. Impact of body mass index on opioid been linked to the opioid epidemic. With increased awareness of consumption in lumbar spine fusion surgery the opioid crisis, the focus postoperatively has shifted to managing surgical site pain while minimizing narcotic use. Numerous studies Taryn E. LeRoy, MD1; Andrew S. Moon, MD1; Marissa Gedman, BA, have compared clinical outcomes and fusion status of different MS2; Jessica P. Aidlen, MD3; Ashley L. Rogerson, MD1 lumbar interbody fusion techniques; however, there is limited 1Tufts Medical Center, Boston, MA, US; 2Tufts University School literature evaluating narcotic consumption postoperatively between of Medicine, Boston, MA, US; 3Newton-Wellesley Hospital Spine techniques. The aim of this study was to assess and compare in- Center, Newton, MA, US house and postoperative opioid consumption among three surgical BACKGROUND CONTEXT: The prevalence of obesity continues techniques. to rise in the United States. The CDC published that from 1999- PURPOSE: To examine posterior lumbar fusion surgical techniques 2000 through 2017-2018 the prevalence of obesity increased and compare opioid consumption across the techniques. from 30.5% to 42.4% and the prevalence of severe obesity nearly STUDY DESIGN/SETTING: Retrospective review. doubled. In lumbar spine surgery, obesity is associated with PATIENT SAMPLE: Three hundred and three patients who increased complications, worse perioperative outcomes, and underwent one- or two-level posterior lumbar interbody fusion higher costs. Obesity is also linked to depression and anxiety, surgery. which have both been shown to increase the use of opioids. We OUTCOME MEASURES: Primary outcome measure was opioid hypothesize that patients who are obese require more opioids consumption across surgical techniques both while in-patient and postoperatively. after discharge as determined by total morphine equivalent dose PURPOSE: To examine the association between body mass index (MED). Secondary outcomes included operative time, length of (BMI) and opioid consumption in patients undergoing lumbar spine stay, and discharge destination. fusion surgery. METHODS: This is a retrospective review of patients who STUDY DESIGN/SETTING: Retrospective review. underwent one- or two-level posterior lumbar interbody fusion PATIENT SAMPLE: Three hundred and six patients who underwent surgery at a single institution between 2016 and 2020. Patients one- or two-level posterior lumbar interbody fusion surgery. were stratified by surgical technique: posterior lumbar interbody OUTCOME MEASURES: Primary outcome measure was opioid fusion (PLIF), minimally invasive transforaminal lumbar interbody consumption across obesity classes both while in-patient and after fusion (MIS-TLIF), and cortical screw (CS) instrumentation with discharge as determined by total morphine equivalent dose (MED). interbody fusion. Age, ASA, BMI, depression, preoperative opioid Secondary outcomes included operative time, length of stay, and use, EBL and OR time were recorded and compared across surgical discharge destination. groups using one-way ANOVA and chi-square analysis. Total METHODS: This is a retrospective review of patients who morphine equivalent dose (MED) was tabulated for both in-house underwent one- or two-level posterior lumbar interbody fusion consumption and postoperative prescriptions and was compared surgery between 2016 and 2020. Patients were stratified by BMI as across surgical techniques using ANOVA analysis. follows: normal weight (18.5-24.9 kg/m2), overweight (25.0–29.9 RESULTS: 303 patients underwent one- or two-level posterior kg/m2), obese I (30.0–34.9 kg/m2), and obese II–III (≥ 35.0 kg/ lumbar interbody fusion between 2016 and 2020. 123 patients m2). Patient demographics and preoperative characteristics were underwent cortical screw instrumentation, 96 underwent PLIF compared across the BMI cohorts using one-way ANOVA and chi- and 84 underwent MIS-TLIF. There was a significantly higher square analysis. percentage of patients who had a history of depression and were on RESULTS: Three hundred and six patients were included in the preoperative opioids in the CS group (p=0.001, p=0.002). Patients analysis, of whom 19.3% (N=59) were normal weight, 38.9% with CS instrumentation required significantly less narcotics per (N=119) were overweight, 24.5% (N=75) were obese I, and 17.3% day while in-house compared to PLIF and MIS-TLIF (MED 80.65 (N=53) were obese II-III. Obesity is associated with significantly vs. 97.85 vs. 83.72, p = 0.030). Patients who underwent CS longer operative times and length of stay (p<0.001, p = 0.19). instrumentation received half the number of narcotics compared to There is no difference in in-house opioid consumption across PLIF patients after discharge (MED 956.15 vs. 2260.89, p = 0.003). groups (p = 0.207). Severely obese patients (Class II-III) are CONCLUSIONS: Patients who underwent CS instrumentation prescribed more than double the number of postoperative opioids required less narcotics postoperatively both while admitted and (p = 0.001). after discharge. CS instrumentation may be associated with less Proceedings 65

postoperative pain due to the less invasive approach, however, narcotics use especially in Asian countries like Pakistan. On the patient education and prescriber practice also play a role in contrary, these narcotics are luxuriously given to patients in the postoperative narcotic consumption. western countries. Main reasons being in developing countries FDA DEVICE/DRUG STATUS: This abstract does not discuss or like Pakistan, the bill of these medicines has to be covered by include any applicable devices or drugs. the patients themselves and not by health insurance companies. Additionally, the addiction to drugs, alcohol and other CNS suppressing agents is also less prevalent in Pakistan. Hence, P12. Prolonged use of narcotics after spine surgery: prolonged and avoidable use of narcotics after spine surgery is A requirement or a privilege more of a privilege than a requirement. FDA DEVICE/DRUG STATUS: Tramadol Hydrochloride (Approved 1 2 Muhammad Tahir Karim, MBBS ; Shehar Yar Abid, MBBS ; Shahid for this indication), Paracetamol (Approved for this indication). Ali, FCPS3 1Orthopedic Surgery Unit-I, Jinnah Hospital, Lahore., Lahore, Punjab, Pakistan; 2Jinnah Hospital, Lahore, Punjab, Pakistan; P13. Smartphone GPS signatures of patients 3Doctors Hospital & Medical Centre, Lahore, Pakistan undergoing spine surgery correlate with mobility and BACKGROUND CONTEXT: Increased use of prescription opioids current gold standard outcome measures over the past 2 decades has been associated with major increases Alessandro Boaro, MD in opioid-related overdoses and addiction treatment. Surgical procedures for patients with chronic painful conditions, such as Brigham and Women's Hospital, Boston, MA, US many orthopedic or spine procedures pose additional challenges, BACKGROUND CONTEXT: Patient reported outcome measures because such patients receive long-term opioids. Deyo, Korff, (PROMs) are currently the gold standard to evaluate patient’s & Duhrkoop (2015) found out that rates of opioid prescribing in physical performance and ability to recover after spine surgery. the US and Canada are two to three times higher than in most However, PROMs have significant limitations due to the qualitative European countries. This ratio is even higher when compared with and subjective nature of the information reported as well as the Asian countries. We sought to estimate the proportion of patients impossibility of using them in a continuous manner. Smartphone who didn’t need to use opioids after the end of 2 weeks following GPS can be used to provide continuous, quantitative, and common spinal surgical procedures and are usually given narcotics objective information on patients’ mobility, allowing an improved for prolonged periods of time needlessly. management of the patient during the recovery period. PURPOSE: The purpose of this study was to find out if the PURPOSE: The aim of this study was to use daily mobility features narcotic analgesics are really required as much as they are usually derived from smartphone GPS to characterize the peri-operative prescribed after spine surgeries or do they just work as a privilege period of patients undergoing spine surgery and to compare these for the patients and the surgeon. objective measurements to the current, gold standard, patient STUDY DESIGN/SETTING: This is a retrospective observational reported outcome measures. study. STUDY DESIGN/SETTING: This study consists of an interrupted PATIENT SAMPLE: This study included 89 patients between the time series design where spine surgery patients were prospectively ages of 25 and 65 years who presented in a major tertiary care assessed through smartphone GPS mobility traces and patient hospital of Lahore, Pakistan. Patients were selected by consecutive reported outcomes measures before and after surgery over a non-probability sampling technique. period of two months. OUTCOME MEASURES: Results were assessed on the basis of PATIENT SAMPLE: A total of 39 patients with evidence of spine post procedure pain and requirement of analgesia. disease (degenerative, tumoral or traumatic) who provided consent METHODS: The study utilized the data of patients operated and underwent spine surgery for their condition where enrolled in from October, 2019 to June, 2020. Adults who underwent 1 of 4 the study at two US academic centers. common spinal surgical procedures (discectomy, decompression, OUTCOME MEASURES: The outcome measures of this lumbar posterolateral fusion or lumbar interbody arthrodesis) were study included: individual measurers of mobility in the form of included in the study while patients with causes of pain other than smartphone GPS derived features, patient reported outcome spine were excluded. Patients were discharged on combination measures (PROMs) in the form of VAS, ODI and PROMIS, the of Paracetamol:325mg & Tramadol (HCl):37.5mg twice daily per measures of correlation between GPS features and PROMs. oral and the patients were assessed at 2, 4 and 8 week intervals. METHODS: Eight daily mobility features were derived from Patients were assessed about the need of narcotics use after the smartphone GPS data in our patient population for a period of specified period of time. The collected data was then analyzed in 2 months starting three weeks before surgery. In parallel, three SPSS v25.0. different PROMs for pain (VAS), disability (ODI) and functional RESULTS: Out of total 89 patients included in the study, 31 status (PROMIS) were serially measured. Segmented linear (34.8%) were males while 58 (65.16%) were females. 31 of the regression analysis was used to assess the trend before and after patients underwent lumbar discectomy, 25 patients underwent surgery. Student’s paired t test was used to compare pre-and post- decompression, 21 patients underwent lumbar interbody PROM scores. Pearson’s correlation was calculated between the arthrodesis and 12 patients underwent lumbar posterolateral GPS signatures and the PROMs scores during the recovery period. fusion. 87.64% of the patients didn’t feel the need to continue the RESULTS: Smartphone GPS features described a reduction in narcotic pain killers after 2 weeks of operation. Only 12.36% of mobility during immediate post-operative period, followed by a the subjects required to continue the narcotics for 4 weeks after progressive and steady increase with a return to baseline values surgery. one month after surgery. PROMs measuring pain, physical CONCLUSIONS: After 2 weeks of surgery, nearly all patients had performance, and disability were significantly different one month discontinued opioid use. These results indicate that spine surgery after surgery compared to the two immediate pre-operative weeks. among opioid-naive patients is not a major driver of long-term The GPS-based features presented moderate to strong linear Proceedings 66

correlation with pain VAS and PROMIS physical score during (summer), 4.4 (fall), and 3.8 (spring). Under the current state the recovery period (Pearson r > 0.7), whereas ODI and PROMIS DTR model, there is one DTR per week, resulting in an average of mental score presented a weak correlation (Pearson r ~0.4). 3.4 (winter), 2.6 (summer), 1.3 (fall), and 0.8 (spring) after-hours CONCLUSIONS: Smartphone-derived GPS features were shown to cases being completed per week. Under the proposed future accurately characterize peri-operative mobility trends in patients state DTR model, which increases the number of DTRs to two in undergoing surgery for spine-related diseases. Features related the winter and summer, the afterhour cases decrease to 1.4 and to time (rather than distance) were better at describing patient 0.6, respectively. Weekday-vs-weekend was determined to affect physical and performance status. Smartphone GPS has the demand for OR time only in the winter (P<0.01), with a sum of potential to be used for the development of accurate, non-invasive procedures completed Friday, Saturday and Sunday averaging 3.3 and personalized tools for patient mobility monitoring after surgery. while procedures completed Monday to Thursday averaging 3.9. FDA DEVICE/DRUG STATUS: This abstract does not discuss or CONCLUSIONS: Based on our preliminary model, seasonality and include any applicable devices or drugs. weekday-vs-weekend have been shown to be significant drivers of demand for OR time. In addition, a spine DTR optimization model has been identified which can meaningfully guide OR scheduling. ePosters: Socio-Economics/Industrial/ With respect to seasonality, our model suggested increasing DTRs Ergonomics to two per week during winter and summer. With respect to the weekday-vs-weekend, timing of the DTR would be optimal on Monday and Thursday. Our next step is to apply autoregressive P14. A case for using machine learning and predictive integrated moving average (ARIMA) time series analysis to a larger analytics combined with linear integer optimization and more detailed dataset to accurately predict future demand to improve operating room resource allocation for based on historical data, allowing for further optimization. The the management of spinal trauma results of this upcoming model have broad implications given Jay Toor, MD1; Aazad Abbas, BS2; Henry Ahn, MD, PhD, FRCSC3; the ease of reproducibility and generalizability to other trauma Jeremie Larouche, MD, FRCSC4; Albert J. Yee, MD, FRCSC4; Joel A. hospitals, as well as to other hospital resources such as inpatient Finkelstein, MD, MSc4 bed capacity. FDA DEVICE/DRUG STATUS: This abstract does not discuss or 1Mississauga, ON, Canada; 2University of Toronto, Toronto, ON, include any applicable devices or drugs. Canada; 3University of Toronto Spine Program, Toronto, ON, Canada; 4Sunnybrook Health Sciences Centre, Toronto, ON, Canada ePosters: Spinal Deformity BACKGROUND CONTEXT: Operating Room (OR) scheduling of trauma cases is a complex issue with significant room for P15. Correlation between the preoperative motion improvement. The Dedicated Trauma Room (DTR) model is analysis results and clinical outcomes in terms of increasing in prevalence across North America to help address this. However, application of this model has shortcomings with Patient Reported Outcomes (PRO) the adult spinal respect to matching supply and demand. Insufficient DTR OR deformity surgery time (underage) leads to after-hours operations, which have Ho-Joong Kim, MD, PhD; Dae-Woong Ham, MD; Jiwon Park, MD; been proven to worsen patient outcomes, increase OR time Byung-Taek Kwon, MD; Ohsang Kwon, MD and decrease efficiency. Conversely, excessive scheduled time Seoul National University Bundang Hospital, Seongnam-si, (overage) results in either unused or last-minute redistribution Gyeonggi-do, Republic of Korea of OR time. We hypothesize that a machine learning algorithm (MLA) can aid in predicting demand for OR time, and thereby BACKGROUND CONTEXT: Motion analysis for gait can provide aid in resource allocation to minimize overage and underage. In information on individual specific dynamic sagittal balance and our study, we compare the current state of DTR scheduling to a walking patterns in patients with adult spinal deformity (ASD). proposed future state that may be further optimized using an MLA. As far as we know, there has been no study to investigate the METHODS: The daily spine service handover emails of the association between the preoperative motion analysis and the orthopaedics department at a major academic hospital over a year patient reported outcomes (PRO) after the ASD surgery. were collected. The following data was extracted using a language PURPOSE: The purpose of this study is to investigate whether processing algorithm: 1) date sent, 2) number of procedures preoperative motion analysis results can predict postoperative completed and 3) admissions. The above variables were used to clinical outcomes in ASD surgery patients. quantify the demand on OR time. A preliminary linear regression STUDY DESIGN/SETTING: Retrospective observational cohort model was performed to determine the variables that significantly study. contributed to demand on OR time. Once the variables were PATIENT SAMPLE: Patients who underwent deformity correction identified, a proposed future state DTR schedule was created using surgery for ASD. a linear integer programming optimization model that minimizes OUTCOME MEASURES: Oswestry Disability Index (ODI), EuroQol the number of after-hours cases eligible for completion in a DTR. (EQ-5D),Preoperative three-dimensional motion analysis. Cases that were eligible were considered those that could be METHODS: Patients who underwent ASD surgery at a single completed non-urgently. This schedule was then compared to the center with motion analysis results were included. Data were current state DTR schedule. collected about patients' demographic characteristics, medical RESULTS: Seasonality and weekday-vs-weekend were two and surgical history. All patients were subjected to preoperative variables determined to significantly affect demand on OR three-dimensional gait analysis using a motion analysis system. time (P<0.01). The mean number of spine trauma procedures Uni- and multivariate regression analyses were performed to find completed per week according to season were 7.2 (winter), 6.2 the predictive parameters of postoperative 12-months ODI. Proceedings 67

RESULTS: A total of 76 patients who met the inclusion criteria were and the interaction between postoperativetime and HGS group enrolled. In univariate regression analysis results, the preoperative on the surgical outcome measures during the follow-up period radiologic sacral slope (SS) and the mean anterior pelvic tilt were analyzed using analysis of variance for repeated measures. angle (Ant-PT) in motion analysis were positively correlated with Nominal categories of surgical technique were analyzed with the postoperative 12-months ODI (β=0.17, p =0.025, and β=0.28, p Chi-square test. =0.010, respectively). Meanwhile, the mean trunk kyphosis (TK) RESULTS: The ODI score at 12 months after surgery was angle in motion analysis results showed a negative correlation with significantly lower in the high HGS group than the low HGS group postoperative 12-months ODI (β=-0.16, p=0.025). In multivariate (P < 0.001), which was best predicted by a multivariate regression regression analysis, stepwise backward elimination and all subsets model including age, gender, BMI, HGS, and preoperative ODI regression were performed to select the final model. The final scores. The overall ODI score, EQ-5D, and VAS for back pain had model showed that the mean Ant-PT was a significant predictor better outcomes in the high HGS group across each follow-up (p=0.021). The simple linear regression analysis showed that Ant- assessment (P < 0.001 for all follow-ups), while they improved PT showed a positive correlation with postoperative sagittal vertical significantly with time after surgery in both groups. axis (SVA) value in all follow-up periods, immediate, 3-, 6-, and CONCLUSIONS: Patients with higher preoperative HGS displayed 12-months with statistical significance. better surgical outcomes, in terms of disability and health-related CONCLUSIONS: The present study highlights that the preoperative quality of life at 12 months after reconstructive spinal surgery for Ant-PT angle in motion analysis was associated with poor ASD. clinical outcomes after the ASD surgery. Examining the sagittal FDA DEVICE/DRUG STATUS: This abstract does not discuss or balance parameters under daily living condition by performing include any applicable devices or drugs. preoperatively dynamic motion analysis might help predict the outcomes after ASD surgery. FDA DEVICE/DRUG STATUS: This abstract does not discuss or P17. Overcorrection of the upper instrumented include any applicable devices or drugs. vertebra relative to the center of the femoral heads is associated with proximal junctional kyphosis 1 2 2 P16. Influence of hand grip strength on surgical Hao-Hua Wu, MD ; Dean Chou, MD ; Kevork HIndoyan, MD ; Jeremy Guinn, BS1; Joshua Rivera1; Ping G. Duan, PhD, MD3; Zhuo outcomes after surgery for adult spinal deformity Xi, MD, PhD4; Shane Burch, MD2; Sigurd H. Berven, MD5 Dae-Woong Ham, MD; Ho-Joong Kim, MD, PhD; Ohsang Kwon, MD; 1San Francisco, CA, US; 2University of California San Francisco, Byung-Taek Kwon, MD; Jiwon Park, MD San Francisco, CA, US; 3The First Affiliated Hospital of Nanchang Seoul National University Bundang Hospital, Seongnam-si, University, Nanchang City, China; 4Neurosurgery Department Gyeonggi-do, Republic of Korea Shengjing Hospital of China Medical University, Liaoning, 5 BACKGROUND CONTEXT: No study has investigated the relation Shenyang, China; Department of Orthopedic Surgery, Keio between hand grip strength and treatment outcome of adult spinal University School of Medicine, Tokyo, Japan deformity correction surgery. BACKGROUND CONTEXT: Although matching lumbar lordosis PURPOSE: This study was done to examine the influence of hand (LL) with pelvic incidence (PI) is an important surgical goal for adult grip strength (HGS) on surgical outcomes of adult spinal deformity spinal deformity (ASD), there is concern that overcorrection may (ASD) patients. lead to proximal junctional kyphosis (PJK). We introduce the upper STUDY DESIGN/SETTING: A prospective observational study. instrumented vertebra – femoral angle (UIVFA) as a measure of PATIENT SAMPLE: Patient who underwent deformity correction appropriate postoperative position in the setting of lower thoracic surgery due to ASD with preoperative HGS test results. to pelvis surgical correction for patients with sagittal imbalance. OUTCOME MEASURES: The Oswestry disability index (ODI), EQ- We hypothesize that a more posterior UIV position in relation to the 5D, and visual analog scale (VAS) for back pain were assessed center of the femoral head is associated with an increased risk of preoperatively, and 3 months, 6 months, and 12 months PJK given compensatory hyperkyphosis above the UIV. postoperatively. The primary outcome measure was ODI scores 12 PURPOSE: The purpose of this study is to evaluate if increased months after surgery. The secondary outcome measures included UIVFA is associated with PJK in operative management of ASD. the overall ODI scores, EQ-5D, and VAS for back pain, assessed at STUDY DESIGN/SETTING: Retrospective Cohort Study each time point during the 12-months follow-up. PATIENT SAMPLE: Adult patients undergoing lower thoracic (T9- METHODS: A total of 78 consecutive patients who underwent T12) to pelvis correction of ASD with a minimum of two-year follow- adult spinal deformity correction surgery were included in this up were included. study. Patients were assigned to either the high HGS (≥ 26 OUTCOME MEASURES: The primary outcome is PJK and proximal kg for men and ≥ 18 kg for women, n = 26) or the low HGS (< junctional failure (PJF). 26 kg for men and < 18 kg for women, n = 52) based on their METHODS: In this retrospective cohort study, adult patients preoperative measurements. The preoperative ODI, EQ-5D, VAS undergoing lower thoracic (T9-T12) to pelvis correction of ASD for back pain, radiological parameters, and demographic data with a minimum of two-year follow-up were included. UIVFA was were compared between the two groups using independent measured as the angle subtended by a line from the UIV centroid t-tests. The primary outcome measure, ODI score (mean and to the femoral head center to the vertical axis. UIV posterior to the 95% confidence interval [CI]) at 12 months after surgery, was femoral head center was positive (+) and UIV anterior the femoral compared using an independent t-test. The secondary outcome head center was negative (-). A >10° kyphotic angle between measures, including the overall ODI score, EQ-5D score, and VAS the UIV and UIV+2 or a >10° increase from pre-op to post-op score for back pain, were assessed between the two groups during were used to determine PJK. Patients with PJK that required all follow-up assessments. To examine the secondary outcome revision surgery were defined as proximal junctional failure measures, the main effects of the HGS group, postoperative time, (PJF). Patients who developed PJK and those who did not were Proceedings 68

compared with preoperative and postoperative UIVFA, change usefulness, safety, and efficacy of C1 pedicle screw insertion. between postoperative and preoperative UIVFA (deltaUIVFA), However, the C1 pedicle screw is not commonly used because sagittal vertical axis (SVA), pelvic tilt (PT), sacral slope (SS), pelvic of the risk of vertebral artery (VA) and C1 root injury due to risk of incidence (PI), lumbar lordosis (LL), pelvic incidence minus lumbar incorrect screw placement when posterior arch thickness is less lordosis (PI-LL), thoracic kyphosis at T5-12 (TK) and the central than 4 mm in the thinnest part of the groove. The current safe sacral vertical line (CSVL). C1 pedicle screw insertion technique requires the guidance of RESULTS: Of the 119 patients included in the study with an lateral fluoroscopic image. Particularly in patients with posterior average 3.6-year follow-up, 51 (42.9%) had PJK and 24 (20.2%) arch thickness of less than 4mm, C1 pedicle screw insertion is had PJF. The average preoperative UIVFA was 7.0±0.7°, the not easy and more fluoroscopy can be required for safe insertion. average postoperative UIVFA 10.8±0.6°, and the average Fluoroscopy is time-consuming and has the risks of cumulative deltaUIVFA was 3.8±0.6°. Patients with PJK had significantly higher radiation exposure. Despite the high radiation exposure required postoperative UIVFA (12.6±4.8° vs. 9.4±6.6°, p=0.04), deltaUIVFA for safe insertion of the C1 pedicle screw using fluoroscopy in (6.1±7.6° vs. 2.1±5.6°, p<0.01), postoperative PT (27.3±9.2 vs. patients with a posterior arch thickness of less than 4 mm, no 23.3±11, p=0.04), postoperative lumbar lordosis (47.7±13.9° studies have compared the accuracy of the C1 pedicle screw vs. 42.4±13.1, p=0.04) and postoperative thoracic kyphosis insertion using fluoroscopy versus using the free-hand technique. (44.9±13.2 vs. 31.6±18.8) than patients without PJK at two-year PURPOSE: This study aimed to describe a free-hand C1 pedicle follow-up. With multivariate logistic regression, postoperative UIVFA screw insertion method in patients with posterior arch thickness of and deltaUIVFA were found to be independent risk factors for PJK less than 4 mm in the thinnest part of the groove, and to compare (p<0.05). DeltaUIVFA was found to be an independent risk factor the clinical and radiological outcomes of C1 pedicle screw insertion for PJF (p<0.05). A receiver operating characteristic (ROC) curve performed using fluoroscopy or the free-hand technique. In for UIVFA as a predictor for PJK was established with an area under addition, we introduce our free-hand technique to insert the C1 the curve of 0.67 (95% CI: 0.59-0.76). Per the Youden index, the pedicle screw through simultaneous direct visualization of the C1 optimal UIVFA cut-off value is 11.5 degrees. pedicle and protection of neurovascular structures, which is similar CONCLUSIONS: The more posterior the UIV is from the femoral to commonly used free-hand C2 pedicle screw insertion. head center after lower thoracic to pelvis surgical correction STUDY DESIGN/SETTING: Retrospective study, comparison study. for ASD, the more patients are at risk for PJK. The greater the PATIENT SAMPLE: We reviewed medical records of all cases of magnitude of posterior translation of the UIV from the femoral C1-2 fixation performed at a single institution between January, head center from preop to postop, the greater the likelihood 2012 and April, 2019. These cases were performed consecutively for PJF. Further investigation into the consequences of sagittal and retrospectively analyzed, yielding a total of 57 cases. Of these overcorrection in the setting of ASD is warranted. cases, 29 utilized C1 lateral mass screw fixation and were excluded FDA DEVICE/DRUG STATUS: This abstract does not discuss or from this analysis. The primary reason for using the C1 lateral include any applicable devices or drugs. mass screw technique rather than C1 pedicle screw insertion was ponticulus posticus, but other reasons for avoiding pedicle screw insertion include different surgeon’s preference. Only one ePosters: Surgery—Cervical surgeon at our institution preferentially chose the C1 pedicle screw approach rather than lateral mass screw except in cases P18. Comparison of the accuracy of C1 pedicle screw of ponticulus posticus, so this analysis reflects outcomes from a fixation using fluoroscopy and free hand techniques single surgeon’s consecutive data. Of the remaining 28 patients, only patients with postoperative computed tomography (CT) scans in patients with posterior arch thickness of less than and at least 3 months of follow up were included. Two patients had 4 mm a posterior arch thickness of more than 4 mm in the thinnest part Byung-Jou Lee, MD1; Jin Hoon Park, MD2 of the groove and one patient who did not undergo a postoperative 1Inje University Ilsan Paik Hospital, Neuroscience & Radiosurgery CT scan were excluded, resulting in a final study population of 25 Hybrid Research Center, College of Medicine, Goyang, Gyeonggi, patients. The primary surgeon utilized fluoroscopy for C1 pedicle South Korea; 2Asan Medical Center, Seoul, Republic of Korea screw insertion from March 2012 through February 2018 in 10 patients, and then transitioned to free-hand technique C1 pedicle BACKGROUND CONTEXT: The atlantoaxial stabilization technique screw insertion for the next 15 patients within the study time is widely used for various atlantoaxial problems such as traumatic, period. degenerative, and tumorous disorders. This method was first OUTCOME MEASURES: In all patients, preoperative CT introduced in 1994 by Goel and Laheri and was later popularized and magnetic resonance imaging (MRI) were performed to by Harms and Melcher, who applied polyaxial screw and rod determine the ideal lengths and diameter of the C1 pedicle systems. Generally, a C1 lateral mass screw fixation technique is screws. All patients also underwent CT angiography to evaluate used for C1–2 stabilization with a C2 pedicle screw. However, the VA morphology. Thin-cut CT was performed to identify screw entry point of the C1 lateral mass screw is covered with the large misplacement immediately after the surgery. The accuracy of paravertebral venous plexus, which can interfere with exposure and the screws was evaluated as follows: grade A (perfectly into the lead to bleeding. In addition, the screw head is close to the C2 root pedicle), grade B (0–2 mm of cortical breach), grade C (2–4 mm of and can cause postoperative occipital neuralgia. The C1 pedicle cortical breach), grade D (4–6 mm of cortical breach), and grade screw fixation technique was introduced by Tan et al. in 2003 as E (more than 6 mm of cortical breach). Grade A and B screws an alternative to the C1 lateral mass screw. This method involves were considered well positioned.19,20 The medical records of placing the screw into the lateral mass through the posterior arch. all patients were reviewed and the following data were collected: Furthermore, in biomechanical studies, the C1 pedicle screw was clinical presentation; follow-up time; radiographic findings with CT stiffer than the C1 lateral mass screw. Anatomic morphometric scan and MRI; and operative information including operative time, studies and primary case series studies demonstrated the estimated blood loss, and operative complications. The assessed Proceedings 69

clinical outcomes included the occurrence of occipital neuralgia follow-up. There was no significant difference in improvement after the surgery and postoperative change in Nurick grade for of Nurick grade between the two groups. After C1 pedicle screw functional improvement. The clinical and radiological outcome insertion using free-hand technique, no patients had iatrogenic measurements of both groups in the preoperative period and 3 neurological deficits or wound infections. months after surgery were reviewed and compared. CONCLUSIONS: This study showed C1 pedicle screw placement, METHODS: Fluoroscopic guidance Patients were positioned using the free-hand technique through the direct visualization of C1 prone, and exposure of the craniocervical junction was performed pedicle, was feasible and safe. The accuracy of C1 pedicle screw in the usual fashion. Sub-periosteal dissection was performed insertion using the free-hand technique was at least as accurate approximately 2 cm lateral to the midline. Since lateral mass as the fluoroscopy in patients with a C1 posterior arch < 4 mm in below the C1 arch was not visualized and exposed for screw thickness. insertion, there was not much bleeding. The medial and lateral FDA DEVICE/DRUG STATUS: This abstract does not discuss or margins of the lateral mass were identified only through palpation include any applicable devices or drugs. using a Penfield no. 4 dissector. Some bleeding from the epidural venous plexus during C1 lateral mass palpation was controlled by compression with a Gelform coagulant. The entry point of the C1 P19. Ambulatory single level posterior cervical pedicle screw was the midpoint on the posterior arch between the foraminotomy for cervical radiculopathy: A palpated lateral and medial margins of the C1 lateral mass. A pilot propensity matched analysis of complication rates hole was created using a 1.8 mm match head type burr, which was 1 1 1 enlarged and deepened with serial drill bits from 2.5 mm to 3.0 Patawut Bovonratwet, MD ; Julia Retzky, MD ; Aaron Chen, BA ; 1 2 mm diameter, followed by 3.5 mm diameter screw insertion. The Nathaniel T. Ondeck, MD, MHS ; Andre Samuel, MD ; Sheeraz A. 2 3 2 trajectory of the screw was approximately 10° of medial angulation, Qureshi, MD, MBA ; Jonathan N. Grauer, MD ; Todd J. Albert, MD and cranial-caudal direction was confirmed using fluoroscopy. 1New York, NY, US; 2Hospital for Special Surgery, New York, NY, US; Free-hand TechniqueAfter positioning and periosteal dissection 3Yale University School of Medicine, New Haven, CT, US of C1 arch as described above, the VA and C1 root were moved BACKGROUND CONTEXT: Single-level posterior cervical cranially with blunt dissection using a Penfield no. 4 dissector. foraminotomy (PCF) for cervical radiculopathy is increasingly being Usually the VA was not visualized, but sometimes could be seen performed as an ambulatory procedure. Despite this increase, spontaneously during dissection. Both the VA and C1 root can there is a lack of published literature documenting the safety of be protected and retracted using the Penfield no. 4 dissector ambulatory PCF. and a suction tip. In addition to protection of the neurovascular PURPOSE: To evaluate for potential differences in 30-day structures, suction and Penfield dissector indicated each medial perioperative complications between ambulatory and inpatient and lateral C1 pedicle margins and gave us clean visualization of single-level PCF. C1 pedicle which was most important in this freehand technique. STUDY DESIGN/SETTING: Retrospective cohort comparison The pilot hole was made by looking directly center of C1 pedicle on study. the C1 arch with a 1.8 mm high-speed match head burr. This hole PATIENT SAMPLE: Patients who underwent single-level PCF for was expanded in depth and width using a 2.5 mm diameter drill bit cervical radiculopathy from the 2005-2018 National Surgical and widened further with a 3.0 mm diameter drill bit to a depth of Quality Improvement Program (NSQIP) registry. 26–30 mm, which was measured with a preoperative CT scan axial OUTCOME MEASURES: Perioperative complications within 30 image. Using this serial dilation technique, we inserted the pedicle days and readmission within 30 days. screw in the C1 pedicle at a diameter of less than 4 mm. Palpation METHODS: Patients who underwent single-level PCF for cervical with a ball tip probe to check for wall violations and hole depth was radiculopathy were identified using ICD and CPT codes from the done during each step. The trajectory was determined by looking 2005-2018 NSQIP registry, which contains multi-institutional directly at the pedicle. A 26–30 mm long screw with a diameter prospectively collected data for the purpose of clinical research. of 3.5 mm was inserted. The Vertex Reconstruction System Ambulatory status was defined as discharge home on same day as (Medtronic Sofamor-Danek, Memphis, TN, USA) was used in all 25 surgery was performed (length of stay of 0 days). To account for patients. After inserting the screws, 3.0-mm rods were applied and potential selection bias due to nonrandom assignment of patients fastened using cap nuts. between the ambulatory and inpatient cohorts, 1:1 matching RESULTS: The mean diameter of the right and left C1 posterior utilizing a propensity score (a single score calculated from available arch at the VA was 3.4 mm and 3.3 mm, respectively in the patient demographic data to match patients between different fluoroscopy group, and 3.3 mm and 3.2 mm, respectively in the treatment groups) was performed. Each ambulatory case was free-hand technique group. In the fluoroscopy group, the accuracy matched with one inpatient case by age, gender, body mass index, of the screws was as follows: 13 screws were Grade A, 3 screws functional status, ASA, diabetes mellitus type, and hypertension. were Grade B, 1 screw was Grade C, and 3 screws were Grade D. Rates of 30-day perioperative aggregated and individual In free-hand technique group, 18 screws were Grade A, 10 were complications, such as readmission, thromboembolic events, Grade B, and 1 was Grade C. There was no significant difference wound complications, and reoperation between the matched between the two groups. However, 96.5% of the screws placed in cohorts were then compared using Chi-squared and Fisher’s exact the free-hand technique group and 80.0% of those placed using tests with Bonferroni correction. In addition, reasons for 30-day fluoroscopy group were rated as safe (Grade A or B). There were readmission after ambulatory single-level PCF were characterized. no known neurological or VA injuries. There were no cases of screw RESULTS: In total, 795 ambulatory and 1,789 inpatient single- revision in either group because incorrectly placed screws did not level PCF cases were identified. After matching, there were 795 cause any symptoms. Postoperative occipital neuralgia occurred ambulatory and 795 inpatient cases. Statistical analysis after in one patient in the fluoroscopy group and did not occur in any propensity score matching revealed no significant difference patients in the free-hand technique group. Most patients improved in individual complications including 30-day readmission, by more than one Nurick grade at the three-month postoperative thromboembolic events, wound complications, and reoperation, Proceedings 70

or aggregated complications between ambulatory vs. matched TXA perioperatively while 69 did not receive TXA. Preoperative inpatient procedures (p>0.004). The most common reasons for 30- diagnoses included spinal stenosis, disc herniation, and day readmission after ambulatory single-level PCF include surgical spondylolisthesis. Distribution of diagnoses was equal among site infections (46%) and pain control (15%). study groups. Patient demographics and comorbidities including CONCLUSIONS: The perioperative outcomes assessed in the age, BMI, cardiovascular disease, respiratory disease, diabetes current study support the conclusion that single-level PCF for and smoking status were evaluated and there were no significant cervical radiculopathy can be performed in the ambulatory setting differences between groups. Patients who received TXA had without increased rates of 30-day perioperative complications significantly lower mean operative blood loss than the non-TXA or readmissions compared to inpatient procedures. However, patients (41.1mL vs 77.4mL p<.05). There was, however, no careful patient selection should be exercised in order to determine significant difference in postoperative drop in hemoglobin (0.7 appropriate ambulatory candidates. vs 1.0, p=.332) or hematocrit (0.0, 1.8, p=.392) between the two FDA DEVICE/DRUG STATUS: This abstract does not discuss or groups. A total of 49 patients in the non-TXA group (71%) required include any applicable devices or drugs. drain placement while 6 patients in the TXA group (43%) had a drain placed (p=.062). There was a trend towards decreased drain output on post-op day 1 in the TXA group compared to the non-TXA P20. Does the use of IV Tranexamic Acid impact group (32.3mL vs 40.8mL, p=.056), however it was not significant. postoperative hemoglobin and hematocrit following There was also no significant difference in average length of stay anterior cervical discectomy and fusion? between TXA and non-TXA patients (3.2 vs. 3.6 days, p=.564). CONCLUSIONS: TXA has been reported as a useful perioperative 1 2 3 Ben Schaffler, MD ; Eric Neufeld, MD ; Terence Ng ; Cesar tool to decrease bleeding associated with spinal surgery. We found 4 5 6 Iturriaga, DO ; Austen Katz, MD ; Alan Job, MD ; Rohit B. Verma, in our patients who underwent ACDF that intraoperative use of 7 MD IV TXA led to a significant decrease in intraoperative blood loss, 1Mineola, NY, US; 2Northwell Health Long Island Jewish Medical however, there was no difference in the change in pre and post- Center, Queens, NY, US; 3Donald and Barbara School of Medicine operative hemoglobin and hematocrit between ACDF patients at Hofstra/Northwell, Hempstead, NY, US; 4New Hyde Park, NY, who received TXA and those who did not. There was also no US; 5Northwell Health Orthopedics, Long Island Jewish Hospital, difference in mean postoperative length-of-stay between the TXA Queens, NY, US; 6Northwell Health North Shore-LIJ, New Hyde and non-TXA groups. Additionally, while not significant, there was Park, NY, US; 7University Orthopaedic Associates, Great Neck, NY, a trend towards TXA patients being less likely to require a drain US postoperatively (p=.062) and those requiring a drain having less output in the early postoperative period (p=.056). While use of BACKGROUND CONTEXT: Spinal surgery is often complicated by TXA perioperatively for ACDF was shown in this study to decrease significant blood loss which can lead to increased patient morbidity operative blood loss, this change was not reflected in surgical and mortality. Tranexamic acid (TXA) is a synthetic antifibrinolytic hemoglobin change or overall length of stay. Further analysis of the agent that has shown promise in decreasing blood loss as well benefits of TXA on bleeding in ACDF patients is warranted. as need for postoperative blood transfusion when given during FDA DEVICE/DRUG STATUS: This abstract does not discuss or surgery. include any applicable devices or drugs. PURPOSE: Recent studies have begun to report on the benefits of TXA when given perioperatively during spinal surgery. Few studies, however, have looked at the effects of TXA in patients undergoing anterior cervical discectomy and fusion (ACDF). In this P21. Does the upper instrumented vertebra or lower study we aimed to evaluate the effectiveness of TXA in reducing instrumented vertebra decision affect the long-term intraoperative blood loss in a cohort of ACDF patients. outcomes after long segment posterior cervical PATIENT SAMPLE: 83 patients undergoing primary ACDF over a 3 fusion? year period. Jamie R. Wilson, MD, FRCS, MSc1; Eric M. Massicotte, MD, MBA, OUTCOME MEASURES: Pre-postoperative hemoglobin and MSc2 hematocrit change. Total operative blood loss. Drain output. Length 1 of stay. Dept. of Neurosurgery, University of Nebraska Medical Center, 2 METHODS: Medical records for all patients who underwent Omaha, NE, US; University of Toronto, Toronto, Ontario, Canada primary ACDF with a single surgeon at a tertiary center over a BACKGROUND CONTEXT: The impact of the choice of the upper 3-year period from September 2016-October 2019 were evaluated and lower instrumented vertebra (UIV, LIV) on the outcomes after retrospectively. All patients who underwent ACDF during this time long-segment posterior cervical fusion (LPCF) has not been well either with or without the augment of TXA were included. The defined. mean differences in intraoperative blood loss as well as the change PURPOSE: The objective of this study was to determine the effect from pre to post-surgical hemoglobin and hematocrit, measured of UIV (C2 or C3) or LIV (Cervical or Thoracic) on the perioperative at presurgical testing 1 week prior to surgery and on post-op day outcomes and complications after LPCF. 1 were analyzed in TXA-treated patients compared to non-TXA- STUDY DESIGN/SETTING: Retrospective cohort study from a treated patients. Additionally, the number of patients requiring single tertiary spine institution. postoperative drain and average drain output on postoperative day PATIENT SAMPLE: Adult patients undergoing long segment #1 were measured. Mean length of stay in between groups was also posterior cervical fusion with an UIV of C2 or C3, and a LIV of C7 or analyzed. This study was subject to IRB approval. T1/2. RESULTS: A total of 83 patients underwent primary ACDF OUTCOME MEASURES: Rates of complication and revision, during the study period. 3 additional patients who underwent Oswestry Disability Index (ODI), pain numerical rating scale (NRS). revision of ACDF were excluded for the purposes of this study. METHODS: Adult patients undergoing LPCF with a UIV of C2/C3 Of the 83 patients who underwent primary ACDF, 14 received were identified from the operative records database. Prospectively- Proceedings 71

collected outcome measures and perioperative complications clear visible bone bridge formation across the index level in 3D-CT. were recorded. Univariate analysis assessed the effect of age, No device-related complications were observed except 8(18.1%) levels fused, UIV and LIV on complication rate, Oswestry Disability cases of cage subsidence without neurologic deterioration. In the Index (ODI), pain numerical rating scale (NRS) and risk of revision subsidence-group, all of the cages were positioned posteriorly surgery. Multivariable regression was used to investigate the effects (more than 3mm distance from the anterior margin of the vertebral of age, UIV, LIV, gender and number of levels on all outcomes. body) and none of the anteriorly placed cages (24 patients, 54.5%) RESULTS: 131 patients were included, with a mean age of showed radiologic signs of subsidence. However, subsidence did 62 [95%CI 60-64] and mean follow up of 47[41-53] months. not correlate with fusion rate or clinical outcomes. Indication for surgery was myelopathy in 95%, with an average CONCLUSIONS: ACDF surgery using stand-alone 3D-PTC of 4 levels fused (range 3-8). Blood loss, duration of surgery, risk demonstrated favorable clinical and radiographic outcomes of complications or revision were equivalent between UIV groups in minimum of 24-month follow-up. Relatively high rate of (p=0.27, p=0.16, p=0.32, p=0.32). Risk of complication was postoperative subsidence was occurred in more posteriorly placed higher in the thoracic LIV group (OR 2.86[1.04-7.87]; p=0.042), cages. 3D-PTC should be placed within 3mm distance from and increased by 1.7[1-2.7; p=0.032] per level fused, without a the anterior margin of the vertebral body to prevent unwanted difference in the revision rate (p=0.61). UIV or LIV groups showed subsidence. no difference in ODI scores or NRS scores, which was unchanged FDA DEVICE/DRUG STATUS: This abstract does not discuss or with multivariable analysis. Increasing age was associated with include any applicable devices or drugs. improved neck NRS (-0.062[-0.11—0.017]; p=0.007) and thoracic LIV was associated with higher arm NRS (2.3[0.36-4.25]; p=0.021). P23. Allograft subsidence has minimal effect on CONCLUSIONS: The choice of UIV (C2 or C3) does not appear cervical alignment following ACDF to affect the risk of complications, revision rate or quality of life 1 1 outcomes after LPCF. Multivariable regression suggests age and a Harold I. Salmons, MD ; Zachariah Pinter, MD ; Anthony L. Mikula, 1 1 1 thoracic LIV has significant effects on post-operative NRS scores. MD ; Ashley Xiong, CCRC ; Arjun S. Sebastian, MD, MSc ; Brett A. 1 1 FDA DEVICE/DRUG STATUS: This abstract does not discuss or Freedman, MD ; Bradford L. Currier, MD ; Benjamin D. Elder, MD, 1 1 2 include any applicable devices or drugs. PhD ; Mohamad Bydon, MD ; Ian D. Kaye, MD ; Christopher K. Kepler, MD, MBA2; Ahmad N. Nassr, MD3; Scott Wagner, MD4 1Mayo Clinic, Rochester, MN, US; 2Rothman Institute, Philadelphia, P22. Fusion rate and subsidence after single level PA, US; 3Mayo Clinic/Dept of Orthopedic Surgery, Rochester, MN, anterior cervical discectomy and fusion (ACDF) using US; 4Walter Reed National Military Medical Center, Bethesda, MD, standalone 3D printed porous titanium cage US Jung-Woo Hur, PhD BACKGROUND CONTEXT: Studies investigating the impact of interbody subsidence in ACDF suggest a correlation between Seoul, Republic of Korea subsidence and worse radiographic and patient-reported BACKGROUND CONTEXT: With the advancement of 3D-print outcomes. To date, no studies have investigated whether allograft technology, porous titanium cages mimicking trabecular bone subsidence is associated with worse postoperative cervical structure have been suggested to decrease the incidence of alignment. postoperative subsidence and enhance bony fusion. PURPOSE: The purpose of this study was to assess whether PURPOSE: The purpose of this study is to demonstrate the clinical allograft subsidence is associated with worse cervical alignment and radiologic results of single-level anterior cervical discectomy following ACDF. and fusion (ACDF) using stand-alone 3D-printed porous titanium STUDY DESIGN/SETTING: Retrospective review of a prospective cage (3D-PTC) in minimum 24-month follow-up in a single institute. cohort of patients undergoing 1 to 3 level ACDF with an allograft STUDY DESIGN/SETTING: Retrospective observational study from interbody and anterior plating at a single academic medical center single surgeon experience between the years of 2011-2017. PATIENT SAMPLE: Forty-five patients with single or two level PATIENT SAMPLE: 66 adult subjects who underwent 1 to 3 cervical disc disease (CDD) underwent ACDF surgery using stand- level ACDF with an allograft interbody and anterior plating were alone 3D-PTC implant between December 2016 and December reviewed. 2018. OUTCOME MEASURES: Cervical alignment and cage subsidence OUTCOME MEASURES: The clinical outcomes were evaluated were measured. using the Visual analogue scales (VAS) scores for neck and METHODS: We performed a retrospective review of a prospective arm pain, neck disability index (NDI) scores and recovery of cohort of patients undergoing 1 to 3 level ACDF with an allograft postoperative dysphagia. The radiologic results were evaluated interbody and anterior plating at a single institution between the with serial plain film and 3D-CT to assess fusion status and device- years of 2011-2017. We collected demographic information and related complications. assessed cervical alignment on standing radiographs performed METHODS: Operations were conducted by a single surgeon in a preoperatively and greater than 6 months postoperatively. Cage single institute under same surgical protocol without any bone graft subsidence was assessed on CT scan performed at least 6 months substitute. All patients completed at least 24 month postoperative postoperatively. Patients with at least one level demonstrating follow-up survey. greater than 4mm of cage subsidence were classified as severe RESULTS: The VAS and NDI scores significantly improved subsidence, while patients with less than 4mm of subsidence at compared with preoperative values and maintained until the last each level were classified as non-severe subsidence. Student’s follow-up survey. Only 6(13.6%) patients complained immediate t-test was used to compare all means between groups. postoperative dysphagia with complete recovery after 1 month. RESULTS: We identified 66 patients for inclusion. The cohort All patients achieved solid bony fusion at the final follow-up with was 43.9% female. 56 patients were classified as non-severe Proceedings 72

subsidence with an average subsidence of 1.80mm, while 10 METHODS: Radiographic evaluation of 70 patients who underwent patients were classified as severe subsidence with an average posterior spinal fusion procedure for degenerative disease using subsidence of 3.28mm across all levels, with the difference in polyaxial screws was performed in a unic center. Among them, subsidence being statistically significant between groups (p=.006). 36 patients were treated using intraoperative 3D computed Preoperative cervical alignment parameters including C2 SVA, C2 tomography (Brainalb, Airo) whereas 34 patients were operated slope, C2-7 lordosis, C1-occiput distance, and T1 slope were not under fluoroscopy or C-arm. ThetaMA (angle between the rod significantly different between groups (p>0.05). On assessment of and screw corps), LambdaMA (angle between the screw and the radiographs obtained greater than 6 months postoperatively, there superior endplate of each instrumented vertebra), EcarT (distance was no significant difference in cervical alignment parameters between posterior wall and the rod) and Mismatch Analysis Index between the severe subsidence and non-subsidence groups (MAI) were measured for each patient in the two groups. (p>0.05). The differences between preoperative and postoperative RESULTS: Intraoperative navigation allows good positionning of cervical alignment parameters were also not significant (p>0.05). the screw and improve LambaMA index. However no significant While 46 of the non-subsided patients achieved arthrodesis difference was found between the two groups of patients according (82.1%), none of the patients in the severe subsidence group did to MAI (means of MAI : group 1 = 4.98 +/- 4.5 ; group 2 = 6.65 +/- (p<.001). Linear regression analysis demonstrated no significant 5.3). correlation between subsidence and C2-7 lordosis (Correlation CONCLUSIONS: Intraoperative navigation allows a better coefficient 0.040, R2 0.001) or C2 SVA (Correlation coefficient positonning of polyaxial screws but it doesn't not improve the 0.251, R2 0.063) (Figure 1). mismatch between rod lordois and lumbar lordosis. A study on a CONCLUSIONS: The present study is the first to assess the impact larger number of patients is needed to confirm these results. of allograft subsidence on cervical alignment following ACDF. FDA DEVICE/DRUG STATUS: This abstract does not discuss or Based upon the results of this study, structural allograft subsidence include any applicable devices or drugs. has minimal impact on overall cervical alignment following ACDF. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. P25. The minimally invasive antepsoas (MIS-ATP) lumbosacral arthrodesis and percutaneous fixation for long spinal fusion of 7 or more segments: A 12 ePosters: Surgery—Thoracolumbar year longitudinal study highlighting safety and effectiveness P24. Evaluation of intraoperative navigation to Chadi Tannoury, MD1; Aziz Saade, MD2; Rahul A. Bhale, BA3; Qasim improve the mismatch between rod bending and S. Ajmi, MBBS, FRCS4; Avilash Das, BA5; Tony Tannoury, MD6 actual postoperative lordosis in lumbar fusion with 1 2 poly axial screws Boston University Medical Center, Boston, MA, US; Boston Medical Center, Boston, MA, US; 3Boston, MA, US; 4QAAST1, 1 2 Thibault Cloche, MD ; Stéphane Bourret, PhD ; Abdollah Y. Moufid, London, United Kingdom; 5Boston University, Boston, MA, US; 3 4 MD ; Jean-Charles Le Huec, MD, PhD 6Boston University School of Medicine, Boston, MA, US 1 Institut Vertebra - Polyclinique Bordeaux Nord Aquitaine, BACKGROUND CONTEXT: Adult spinal deformities requiring 2 Bordeaux, France; Polyclinique Bordeaux Nord Aquitaine, long fusions to the lumbosacral junction are notorious for L5-S1 3 Bordeaux, France; Chu Poitiers Inite Rachis, Poitiers, France; pseudarthrosis and distal hardware related complications. The 4 Bordeaux, France minimally invasive ATP technique allows for substantial anterior BACKGROUND CONTEXT: Despite a good rod bending during column reconstruction thereby reducing the risk of posterior lumbar fusion surgeries, a mismatch can be observed between hardware failures (HF). the rod bending angle and the final lordosis of the fused segment. PURPOSE: This study is the first to investigate the incidence of This mismatch can lead to a failure in the restoration of the sagittal posterior hardware related complications following long segment balance and it is a risk factor of developing adjacent segment fusion (7 or more vertebrae) using MIS-ATP and posterior disease in short fusion. Three radiological factors are involved in percutaneous fixation (PPF). the mismatch between rod bending and lumbar lordosis during STUDY DESIGN/SETTING: Retrospective cohort study posterior lumbar fusion with polyaxial screws. This mismatch is PATIENT SAMPLE: Adult patients who underwent thoraco-lumbo- smaller when polyaxial screws are 1) perpendicular to the rod, 2) sacral fusions with or without pelvic fixation using MIS-ATP and parallel to the superior vertebral endplate and 3) have the same PPF between 2008 and 2019. depth. The combination of these 3 factors was called Mismatch OUTCOME MEASURES: Demographic, clinical, and surgical Analysis Index (MAI). Improvement of MAI is a key factor for the collected information included: age, gender, smoking status, follow- restoration of an economic sagittal balance and the use of patient- up duration (years), preoperative diagnosis, number of anterior specific spinal rods. and posterior levels fused, associated complications and revision PURPOSE: The purpose of this study is that intraoperative 3D surgeries. Pseudarthrosis, hardware-related, infectious and neuro- navigation can improve the Mismatch Analysis Index during short vascular complications were evaluated. fusion spinal surgery. METHODS: This is a retrospective review of patients who STUDY DESIGN/SETTING: Monocentric and retrospective analysis underwent long spinal fusion (MIS-ATP + PPF) to the sacrum and PATIENT SAMPLE: 70 patients with degenerative spinal disease pelvis for the management of adult spinal disorders between 2008 who underwent a short spinal fusion procedure using polyaxial and 2019. Postoperative clinical and radiographic complications screws. The population was divided in two groups: group 1: surgery were collected and analyzed. The following postoperative variables done using intraoperative navigation; group 2: control group. were collected: surgical site infections, neuro-vascular injuries, OUTCOME MEASURES: The Mismatch Analysis Index (MAI) was implant fracture, implant displacement, hardware prominence and compared between the two groups. related pain, pseudarthrosis, bony fractures, junctional disease Proceedings 73

(proximal and distal), and need for surgical revision. operation or procedure (i.e. post-operative discitis or SEA) were RESULTS: 143 patients were included in this study (72.7% excluded. females, average age 65.8 years). 62 patients (43.4%) never OUTCOME MEASURES: Patient demographics, including mean smoked, 49 patients (34.3%) were former smokers, and 32 patients age, sex, source of infection, comorbidities, presenting symptoms, (22.3%) were active smokers. The most common indications for spinal levels of involvement, length of stay, and 30-day readmission fusion included: degenerative scoliosis (76.9%) and degenerative were studied. Primary outcomes measures were reoperation rate, spondylolisthesis (17.5%). The average number of fused vertebrae complication rate, and clinical outcomes. per individual was 8.7. The most common levels fused were: METHODS: Patients were divided into two groups: those who T12-S1 Anterior / T10-S1 Posterior (53.1%). 44 patients (30.8%) initially underwent decompression alone and those who initially experienced a total of 48 complications. These included: deep underwent decompression with fusion. Operative notes, imaging infections (4.2%), painful iliac hardware (5.6%), pedicle screw studies, and other clinical records were reviewed. Frequency complications (6.3%), and proximal junctional disease (9.8%). Of distributions and summary statistics were calculated for all these, 30 patients (21%) required a revision surgery, mostly due to clinical and radiographic variables. Fisher exact tests were used proximal junctional disease (8 patients; 5.6%). Pseudarthrosis was to compare distributions for categorical variables, and t-tests were noted in 3 patients (2.1%). used to investigate differences in the distributions of continuous CONCLUSIONS: Long spinal fusions to the sacrum and pelvis are variables between subsets of patients classified by dichotomous technically challenging and notorious for hardware failure and data. A p-value of ≤ 0.05 was considered significant. revision surgeries. In our experience, the use of minimally invasive RESULTS: A total of 74 patients with spinal infection were reviewed ATP fusion coupled with PPF along with iliac instrumentation and 47 patients met the inclusion criteria. There were 27 (57.4%) provided a protective effect against posterior HF. Only 3 patients patients who underwent decompression alone and 20 (42.6%) (2.1%) developed pseudarthrosis. Furthermore, additional patients who underwent decompression and fusion. There were benefits of the MIS-ATP technique are inherent to its relatively safe no significant differences in the comorbidities, level and/or extent approach-related profile. of infectious involvement between the decompression alone FDA DEVICE/DRUG STATUS: Iliac-pelvic screw implants cohort and the decompression with fusion cohort. The reoperation (Approved for this indication), pedicle screw implants (Approved rate was significantly higher in the patients who underwent for this indication), Posterior longitudinal rod implants (Approved decompression alone (51.9% vs 10%, p = 0.004), which was a for this indication), Interbody Fusion Implant-Cage Devices larger difference than reported in previous investigations by other (Approved for this indication) authors. No significant difference was seen between groups with regards to complication rates or neurological outcomes. There was a trend towards discitis at the level of laminectomy (seen P26. The role of instrumentation in the surgical as increased T2 signal within the disc space) being a predictor treatment of spondylodiscitis and spinal epidural for reoperation for fusion/stabilization in patients undergoing abscess: A single center retrospective cohort decompression alone, but this did not reach statistical significance (p = 0.1071). 1 2 Jonathan Lee, MD ; Sean M. Barber, MD CONCLUSIONS: Additional studies are needed before reliable 1Houston Methodist Neurological Institute, Houston, TX, US; conclusions may be drawn, and patients with spinal infection 2Houston, TX, US should be managed according to their unique clinical scenario, but the results of this study suggest that decompression with BACKGROUND CONTEXT: Spondylodiscitis is an uncommon instrumented fusion for patients with SEA results in similar infection of the intervertebral disc with osteomyelitis of the complication rates and significantly lower reoperation rates when adjacent vertebral body endplates and represents 0.15 to 5% of compared with decompression alone. all osteomyelitis cases. The treatment of spondylodiscitis varies FDA DEVICE/DRUG STATUS: This abstract does not discuss or from conservative medical management to surgical decompression include any applicable devices or drugs. with or without instrumented fusion, depending on a multitude of factors. While decompression of the neural elements is often the primary goal of surgical intervention for SEA, the degree of bony and ligamentous destruction related to the infectious process P27. Diffuse idiopathic skeletal hyperostosis has at times led surgeons to supplement the decompression with extended to the lumbar segment is a risk factor of spinal stabilization out of concern for underlying instability. Little reoperation in patients treated surgically for lumbar consensus currently exists regarding the use of instrumentation stenosis in patients undergoing decompression for SEA, and reports of Kentaro Yamada, MD1; Yuichiro Abe, MD, PhD2; Hiroaki Nakamura, differences in complication rates and reoperation rates between MD, PhD1 those undergoing decompression alone compared with those 1 undergoing decompression and fusion are variable. Osaka City University Graduate School of Medicine, Osaka City, 2 PURPOSE: Our goal was to better understand the advantages and Japan; Eniwa Hospital, Eniwa, Japan limitations of each technique (decompression vs decompression BACKGROUND CONTEXT: In patients with diffuse idiopathic with instrumented fusion) in the treatment of SEA. skeletal hyperostosis (DISH), the segments without ossification are STUDY DESIGN/SETTING: This study consisted of a retrospective, exposed to higher mechanical stress, which has been thought to comparative chart review. cause poor clinical results in cases of acute spinal trauma. DISH PATIENT SAMPLE: Records of patients undergoing operative might similarly affect clinical outcomes in patients with lumbar intervention for spondylodiscitis at the authors’ institution between spinal stenosis (LSS), because of magnification of mechanical 2011 and 2018 were reviewed. Patients were selected who stress on lower non-fused segments. However, no studies have underwent neurosurgical intervention for a SEA. Patients who investigated in detail DISH as a potential risk factor of poor surgical developed spondylodiscitis or SEA as a result of a recent spinal results for LSS. Proceedings 74

PURPOSE: to investigate the association between DISH and P28. Risk factors for reoperation after reoperation in patients treated surgically for LSS in long-term decompression for lumbar spinal stenosis in patients results. STUDY DESIGN/SETTING: Observational study. with diffuse idiopathic skeletal hyperostosis PATIENT SAMPLE: This study included 1063 responders to a extended to lumbar segment postoperative postal survey out of 2363 consecutive patients who Kentaro Yamada, MD1; Yuichiro Abe, MD, PhD2; Hiroaki Nakamura, underwent surgery for LSS between 2002 and 2010. MD, PhD1 OUTCOME MEASURES: Lumbar reoperations due to progression 1Osaka City University Graduate School of Medicine, Osaka City, of degeneration, or non-union after fusion surgeries from postal Japan; 2Eniwa Hospital, Eniwa, Japan survey or medical records. METHODS: The survey included questions about reoperations BACKGROUND CONTEXT: Diffuse idiopathic skeletal hyperostosis performed at another hospital and the patient-reported outcomes. (DISH) begins most frequently in the lower thoracic spinal DISH was evaluated by preoperative standing whole-spine segments and extends to the upper thoracic segments and lumbar radiographs. Cox proportional hazards regression were performed spine. DISH which extended to lumbar segment (L-DISH) has to investigate DISH as a predictor of reoperation, with adjusting been reported as an independent risk factor for reoperation after for demographics, concomitant pathologies (degenerative surgery for lumbar spinal stenosis (LSS) (Yamada K. Spine 2018). spondylolisthesis or degenerative lumbar scoliosis), and surgical The increased mechanical loading to lower non-ossified segments procedures. Kaplan–Meier survival plot were also examined. in patients with L-DISH might be the cause of increasing revision Furthermore, characteristics of poor outcomes in patients surgery, however, it is still unclear about characteristics of poor with DISH were investigated. We also assessed selection bias surgical outcome in patients with L-DISH. by examining the differences between responders and non- PURPOSE: to investigate risk factor for reoperation in patients responders to a postal survey. with L-DISH in detail by the minimum 5 years follow-up of the RESULTS: Reoperations were performed in a total of 115 patients decompression surgery. (10.8%) within an average of 8.6 years after the initial surgeries. STUDY DESIGN/SETTING: Retrospective observational study. Patients who only had DISH were not associated with reoperation, PATIENT SAMPLE: This study included 57 patients with L-DISH however, reoperations were performed significantly more often (male 48 cases, mean age 69.5 years) out of489 responders to a in patients with DISH extended to the lumbar segment (L-DISH) postoperative postal survey who underwent decompression-alone than in patients without (22% and 7.3%, respectively; p < 0.001). procedure for LSS between 2002 and 2010. Cox analysis showed that L-DISH was one of the significant OUTCOME MEASURES: Reoperations at same level of the index independent predictors for reoperation (hazard ratio 2.05, p = procedures due to progression of degeneration from postal survey 0.009). More reoperations ≥1 year after the initial surgery were or medical records. performed in patients with L-DISH than in those without L-DISH METHODS: We have performed conventional medial facetectomy (p = 0.005). The cause of reoperation did not differ between the as decompression-alone procedure for LSS. The postoperative patients with and without L-DISH. The patients with stenosis postal survey included questions about reoperations performed adjacent to the caudal end of DISH had a high reoperation rate at another hospital and the patient-reported outcomes. DISH was (3 of 7 patients, 42.9%), although there were no significant (p evaluated by preoperative standing whole-spine radiographs. = 0.443). Several factors, but not L-DISH, were significantly Univariate and multiple logistic regression analysis were performed associated with responders to the survey. to investigate predictor of reoperation. Explanatory variables were CONCLUSIONS: The present study indicated L-DISH was investigated by demographics, parameters by preoperative plain independently associated with reoperation for LSS. Surgery-free radiographs, segmental intervertebral cleft and ≥2mm of facet survival was significantly shorter in patients with L-DISH than in opening by preoperative CT, and disc degeneration (Pfirmann those without L-DISH. The decreased number of lumbar mobile grade) and endplate change (Modic type) from preoperative MRI. segments due to L-DISH might lead to unfavorable outcomes. The Influences of DISH were evaluated by the number of vertebrae result suggests a negative effect of increased mechanical load not involved by DISH and sum of Mata’s grade of lumbar level as the only on the caudal end of DISH but also on the separated caudal evaluation for ossification in segments even without complete remaining segment, except extremely far from DISH end. Although ossification. low follow-up rate was the biggest limitation of the study, the main RESULTS: The mean number of vertebrae involved by DISH regarding L-DISH is valid for discussion because the presence was 8.8. The sum of Mata’s grade of lumbar segment was mean of L-DISH was not associated with either the responders or non- 4.7. A total of 10 patients (17.5%) and 11 segments underwent responders. Careful follow-up of patients is needed after surgery for reoperation at the index levels during mean 9.2 years follow- LSS with L-DISH. up. Univariate analysis indicated significant association with FDA DEVICE/DRUG STATUS: This abstract does not discuss or reoperation in surgical period (surgery ≥10 years ago, p=0.012), include any applicable devices or drugs. ≥ 10 degrees of segmental sagittal ROM by dynamic radiograph (p=0.014), and facet opening by CT (p=0.009). Independent risk factors for reoperation by multivariate analysis were surgical period and facet opening (adjusted odds ratio 17.4, p=0.013). CONCLUSIONS: Morphologic assessments of DISH were not associated with reoperation, but facet opening by CT was associated. Facet opening was reported as a predictor of segmental lumbar instability (Hasegawa K. JNS 2010). Patients with L-DISH frequently have some ossification in lower lumbar segments, and difficult to assess segmental instability by dynamic radiographs. Facet opening might be useful parameter to assess instability Proceedings 75

which leads reoperation especially in rigid lumbar spine like for symptomatic lumbar disc herniation and it involves removal of L-DISH. In conclusions, facet opening by CT was the independent a portion of intervertebral disc pressing the nerve root or spinal risk factor for reoperation at index levels after decompression for cord or both. Discectomy can be done either by open technique LSS in patients with L-DISH. or minimally invasive techniques like Loupe assisted discectomy. FDA DEVICE/DRUG STATUS: This abstract does not discuss or Minimally invasive discectomy has benefits like less blood loss, less include any applicable devices or drugs. post-operative pain, less chances of iatrogenic injuries to nerve roots or spinal cord, shorter hospitalization period and early return to work. P29. Microendoscope assisted versus open posterior PURPOSE: To evaluate the efficacy of loupe-assisted discectomy in lumbar interbody fusion for lumbar degenerative patients with lumbar disc herniation. disease: A multicenter retrospective cohort study STUDY DESIGN/SETTING: It is a retrospective observational study. PATIENT SAMPLE: A sample of 61 consecutive patients was taken Masayoshi Fukushima, MD who were operated in a major tertiary care hospital of Lahore. Tokyo, Japan OUTCOME MEASURES: Using the Modified Macnab’s Criteria (MMC), the long-term functional outcomes i.e. ability to return to BACKGROUND CONTEXT: Minimally invasive surgery normal work were assessed at 6 months follow up. has become popular for posterior lumbar interbody fusion METHODS: The study took data from patients of herniated (PLIF). Microendoscope-assisted PLIF (ME-PLIF) utilizes a lumbar disc who were between the ages of 18 – 80 years and microendoscope within a tubular retractor for PLIF procedures; were operated by the same surgeon over the period of 1 year. however, there are no published reports that compare ME-PLIF to Patients with spinal canal stenosis, previous history of lumbar disc open PLIF. surgery and patients with multilevel disc herniation were excluded PURPOSE: We compare the surgical and clinical outcomes of ME- from the study. A purpose built questionnaire was used to record PLIF with those of open PLIF. demographic and clinical data. Preoperative pain score by the STUDY DESIGN/SETTING: This was a multicenter retrospective pain VAS and functional outcomes by the MMC were assessed cohort study. upon enrollment in the study. The postoperative pain score by the PATIENT SAMPLE: A total of 155 consecutive patients who pain VAS and functional outcomes by the MMC were assessed underwent single-level PLIF for degenerative lumbar diseases at six-month follow-up. Data was entered and analyzed by using between April 2017 and June 2018 were registered prospectively. statistical package for social sciences (SPSS) version 22. Of the 149 patients with a complete set of preoperative data, 72 RESULTS: 39 out of 61 patients were females while 22 were males. patients underwent ME-PLIF (ME group) and 77 underwent open L4-L5 was the most common level of surgery and 42 (68.8%) PLIF (open group). patients had surgery of this level. The number of patients having OUTCOME MEASURES: Outcome measures were operative date, surgeries of L3-L4, L2-L3 and L1-L2 were 11 (18%), 6 (9.8%) postoperative complications, clinical outcomes and radiographic and 2 (3.2%) respectively. 58 (95%) patients reported no pain findings at one year after surgery. or restriction of mobility at 6 months follow up and hence, fell in METHODS: We compared the clinical and radiographic findings in Excellent category of the MMC. Only 3 (5%) patients reported both ME group and open group. occasional non-radicular pain and fell in Good category of the MMC. RESULTS: Of the 149 patients, 57 patients in ME-group and 58 None of the subjects were still handicapped or reported continued patients in open-group were available. The ME-PLIF procedure objective symptoms of root involvement after the surgery. required a significantly shorter operating time and involved less CONCLUSIONS: The long-term results of loupe assisted lumbar intraoperative blood loss. Three patients in both groups reported discectomy are substantial and almost all the patients in the study dural tears. Three patients in ME-group experienced postoperative got back to their normal routine of physical activities. So, Loupe complications, compared to two patients in the open-group. The assisted discectomy is safe and comparable with endoscopic fusion rate in ME-group at one year was lower than that in open discectomy and other minimally invasive modalities of discectomy. group (p=0.06). The proportion of patients who were satisfied was FDA DEVICE/DRUG STATUS: This abstract does not discuss or significantly higher in the ME-group (p=0.02) include any applicable devices or drugs. CONCLUSIONS: ME-PLIF was associated with equivalent post-surgical outcomes and significantly higher rates of patient satisfaction than the traditional open PLIF procedure. However, the fusion rate after ME-PLIF tended to be lower than that after the P31. Evaluation of the clinical result of combination traditional open method. of LIF with CBT screw as a minimally invasive FDA DEVICE/DRUG STATUS: This abstract does not discuss or approach for lumbar interbody fusion surgery include any applicable devices or drugs. Seiji Otsuka, MD, PhD Dept. of Orthopedic Surgery, Toyokawa City Hospital, Toyokawa, Japan P30. Functional outcomes of Loupe Assisted Discectomy in patients with lumbar disc herniation BACKGROUND CONTEXT: Japan has entered an unprecedented aging society. Accordingly, opportunities for surgical treatment 1 2 Shehar Yar Abid, MBBS ; Muhammad Tahir Karim, MBBS ; Shahid for patients with lumbar degenerative diseases accompanied 3 Ali, FCPS by osteoporotic spine are rapidly increasing. Along with this, 1Jinnah Hospital, Lahore, Punjab, Pakistan; 2Orthopedic Surgery complications due to bone vulnerability, such as loose screws and Unit-I, Jinnah Hospital, Lahore., Lahore, Punjab, Pakistan; 3Doctors bone dysfunction, are increasing, and various efforts are being Hospital & Medical Centre, Lahore, Pakistan made to overcome them. We have been used the LIF (Lateral interbody fusion) as a minimally invasive method for lumbar fixation BACKGROUND CONTEXT: Discectomy is a standard procedure such as the correction of the adult spinal deformity, or indirect Proceedings 76

decompression for the spondylolisthesis and lumbar canal stenosis P32. Preoperative cross-sectional area of psoas so far. Meanwhile, the cortical bone trajectory (CBT) technique, muscle impacts short term functional outcomes which provides high vertebral fixation stability and low invasiveness and is profitable for the fixation of an osteoporotic spine, has after posterior lumbar surgery been used for a posterior fixation method of LIF on the basis of Hikari Urakawa1; Kosuke Sato, MD1; Avani S. Vaishnav, MBBS1; the strategy that a combination of a big cage of LIF and the CBT Sohrab Virk, MD2; Yoshihiro Katsuura, MD1; Evan Sheha, MD3; technique must provide additional high stability. Takashi Kaito, MD, PhD4; Catherine Himo Gang, MPH1; Sheeraz A. PURPOSE: The purpose of this study is to evaluate the clinical Qureshi, MD, MBA1 result of this method, combination of the CBT screw and LIF. 1Hospital for Special Surgery, New York, NY, US; 2Northwell Health, STUDY DESIGN/SETTING: Prospective nonrandomized clinical Garden City, NY, US; 3HSS Stamford, Stamford, CT, US; 4Suita, study on the clinical outcome and radiographic findings of the Osaka, Japan combination therapy of lateral interbody fusion procedure and CBT technique. BACKGROUND CONTEXT: The decreased psoas cross-sectional PATIENT SAMPLE: A total of 40 consecutive patients that we could area has been used as a parameter of sarcopenia and reported follow-up more than one year were retrospectively reviewed. to be a predictor of increased risk of mortality and complications OUTCOME MEASURES: The patient’s pre-operative and 12-month in various surgery including spine surgery. However, it is unclear follow-up radiographic assessment were checked from plain which level should be selected to measure it on MRI and whether sagittal, coronal and axial CT image and sagittal, axial views. JOA the psoas size impacts postoperative functional outcomes in score, JOABPEQ (JOA back pain Questionnaire), VAS (Visual analog lumbar surgery. scale) of leg pain, paresthesia and low back pain were evaluated as PURPOSE: To (1) elucidate the optimal level for the measurement clinical outcome. by examining the inter-rater reliability at each level and (2) METHODS: A total of 40 consecutive patients that we could investigate the impact of psoas cross-sectional area on short-term follow-up more than one year were retrospectively reviewed. functional outcomes of posterior lumbar surgery. The Radiographic assessments were done by an independent STUDY DESIGN/SETTING: Retrospective cohort study. spine surgeon using medical imaging software and those are PATIENT SAMPLE: 212 patients who underwent minimally included a fusion rate, a ratio of bone cyst formation around the invasive posterior lumbar surgery for degenerative lumbar diseases. endplates, a ratio of CBT screw loosening. Moreover JOA score, OUTCOME MEASURES: Intraclass correlation coefficient (ICC) JOABPEQ (Japanese Orthopedic Association Back Pain Evaluation at each level for the purpose 1 and patient reported outcome Questionnaire) and VAS score (low back pain, leg pain, leg measures (PROMs) including ODI, VAS back, VAS leg, SF-12 PCS, paresthesia) were also evaluated as a patient – based outcome. SF-12 MCS and PROMIS PF at pre-op, 2 weeks, 6 weeks, 3 months RESULTS: In all, 22 male patients and 18 female patients (mean and 6 months for the purpose 2. age,72.4 years; range 41-93 years) underwent LIF procedure and METHODS: The cross-sectional area of psoas muscle was inserted CBT screws (264 screws) in a lateral or prone position. measured at each intervertebral level on T2-weighted axial images This procedure was performed for 9 spondylolisthesis, 21 spinal of preoperative MRI by two observers. Normalized total psoas area canal stenosis with low back pain, 7 adult deformity and 3 disc (NTPA) (mm2/m2) was calculated as total psoas area normalized degenerative diseases. An intervertebral fusion rate was 96.3% to patient height. NTPA at the level with the highest ICC was used (77/80 fused levels). A bone cyst formation around endplate was as a parameter in this study. Functional outcomes were compared detected in 2 fused lelvel (2.5%). A ratio of CBT screw loosening between patients with the lowest sex-specific quartile of NTPA was 2.7 %. Lumbar JOA score, JOABPEQ except for lumbar spine [low NTPA group (LG)] and the remainder [high NTPA group (HG)]. dysfunction and VAS were all statistically improved at one year A multivariate analysis was performed to elucidate independent status after surgery. predictors associated with failure to reach minimal clinically CONCLUSIONS: The combinational methodology of the important difference (MCID) in each functional outcome at 6 intervertebral large cages for LIF and CBT screw technique months. provides high stability for fixation of vertebrae without any RESULTS: ICC was highest at L3/4 [0.992 (95%CI 0.987-0.994)] formation of bone cyst around endplate and is really useful for bony compared to the other three measured levels [L1/2 0.983 (0.973- union and improvement of clinical index. 0.989), L2/3 0.991 (0.986-0.994), L4/5 0.928 (0.893-0.952)]. FDA DEVICE/DRUG STATUS: This abstract does not discuss or There were no significant differences in preoperative PROMs include any applicable devices or drugs. between groups apart from SF-12 MCS, which was significantly higher preoperatively in the LG. All of those PROMs were significantly worse at multiple timepoints in the LG postoperatively. Multivariate logistic regression demonstrated that low NTPA was an independent predictor of failure to reach MCID in ODI (OR = 2.68; 95% CI, 1.26-5.67; p = 0.010) and VAS leg (OR = 2.43; 95% CI, 1.13-5.20; p = 0.022). CONCLUSIONS: The decreased psoas cross-sectional area on preoperative MRI had a negative correlation with short-term functional outcomes after posterior lumbar surgery. Low NTPA, a sarcopenia-related parameter, was an independent predictor of failure to reach MCID in ODI and VAS leg at 6 months. NTPA is a highly reliable and readily assessable measure of muscle health and may be a useful tool to inform treatment options and postoperative expectations in individual patients. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. Proceedings 77

P33. Resolution of back pain following one-level CONCLUSIONS: Following MI-TLIF, patients with lower extremity neurologic symptoms with and without a significant component minimally invasive transforaminal lumbar interbody of back pain have improvements in back pain, leg pain, and ODI fusion regardless of their primary presenting pain complaint; however, Kyle W. Morse, MD1; Ram K. Alluri, MD2; Avani S. Vaishnav, MBBS1; patients who presented with predominantly leg pain were more Sohrab Virk, MD3; Evan Sheha, MD4; Catherine Himo Gang, MPH1; likely to meet MCID criteria for improvement in their back pain Sheeraz A. Qureshi, MD, MBA1 and ODI score.ollowing MI-TLIF, patients with lower extremity 1Hospital for Special Surgery, New York, NY, US; 2LAC USC, Los neurologic symptoms with and without a significant component Angeles, CA, US; 3Northwell Health, Garden City, NY, US; 4HSS of back pain have improvements in back pain, leg pain, and ODI Stamford, Stamford, CT, US regardless of their primary presenting pain complaint; however, patients who presented with predominantly leg pain were more BACKGROUND CONTEXT: Minimally invasive transforaminal likely to meet MCID criteria for improvement in their back pain and lumbar interbody fusion (MI-TLIF) is a commonly used procedure ODI score. to treat degenerative pathology in the lower lumbar spine that FDA DEVICE/DRUG STATUS: This abstract does not discuss or requires decompression and fusion. Patients undergoing MI-TLIF include any applicable devices or drugs. frequently present with lower extremity neurologic symptoms with or without associated lower back pain. While previous studies have demonstrated good to excellent outcomes after MI-TLIF for P34. Outcomes of combined thoracic anterior and neurologic symptoms as well as improvements in clinical outcome scores, the resolution of back pain as a presenting symptom while lumbar posterior tethering versus posterior spinal accounting for the impact of pre-operative alignment remains fusion underreported following MI-TLIF. Hao-Hua Wu, MD1; Satvir Saggi, BS2; Toshali Katyal, BA3; Sachin PURPOSE: The purpose of this study was to compare clinical and Allahabadi, MD4; Jeremy Siu, BS1; Mohammad Diab, MD5 radiographic outcomes of patients undergoing MI-TLIF with lower 1San Francisco, CA, US; 2Milpitas, CA, US; 3Oakland, CA, US; extremity neurologic symptoms with and without a significant 4University of California, San Francisco Department of Orthopaedic component of back pain. Surgery, San Francisco, CA, US; 5University of California - San STUDY DESIGN/SETTING: A retrospective review of prospectively Francisco (UCSF), San Francisco, CA, US collected data from a single surgeon surgical database from 2017 to 2019 was performed. BACKGROUND CONTEXT: In the treatment of skeletally immature PATIENT SAMPLE: The surgical database was queried for patients idiopathic scoliosis, outcomes for combined Thoracic Anterior and who underwent primary single-level MI-TLIF for degenerative Lumbar Posterior Tethering (TALPT) and posterior spinal fusion and conditions of the spine who had failed non-operative management. instrumentation (PSF) have never been compared. Patients with less than 1 year of follow-up, and those who PURPOSE: The purpose of this study is to compare the outcomes underwent surgery for trauma, tumor or infection were excluded. of TALPT with PSF in skeletally immature patients with idiopathic OUTCOME MEASURES: Patient demographics, pre-operative scoliosis. opioid usage, length of stay (LOS, hours), patient-reported outcome STUDY DESIGN/SETTING: Retrospective Cohort Study measures (PROMs), and radiographic parameters were collected. PATIENT SAMPLE: Skeletally immature patients with curves of at PROMs including Oswestry Disability Index (ODI), VAS-back, and least 40 degrees with at least two-year follow-up who underwent VAS leg pain were collected. Radiographic measurements including TALPT or PSF from 2014-2018 were included. pelvic tilt, sacral slope, pelvic incidence (PI), lumbar lordosis (LL), OUTCOME MEASURES: The primary outcome is revision. and PI-LL mismatch. Secondary outcomes include procedure duration, estimated blood METHODS: Patients were divided into two groups: Leg Pain loss (EBL), length of stay (LOS), total postoperative opioid morphine Predominant (patients reported greater than 50% leg pain upon equivalent (OME), foley duration, days to solid food, direct cost and presentation) and Non-Leg Pain Predominant (patients reported 30-day readmission. 50% or greater back pain). Multivariate analysis was performed METHODS: In this IRB-approved retrospective cohort study, TALPT to determine differences between groups based upon any and PSF were compared with respect to primary and secondary significantly baseline characteristics. Minimal clinical importance outcome measures. TALPT patients underwent a single-stage open difference (MCID) for ODI was 14.9, VAS-leg 2.8, and VAS-back anterior tethering for the thoracic curve and unilateral posterior 2.1. Patients whose preoperative scores were lower than the MCID tethering on the convexity of the lumbar curve. threshold were excluded from this analysis. RESULTS: Of 104 enrolled patients, 6 (5.8%) underwent TALPT RESULTS: Sixty patients underwent MIS-TLIF, of which 51 (85%) while 98 (94.2%) underwent PSF. There was no significant had information available regarding their pre-operative pain rating. difference in revision rate between TALPT and PSF (33% vs. 11%, Twenty-nine patients (29%) had predominantly back pain and 22 p=0.26). TALPT patients had significantly longer ICU length of stay (43%) had predominantly leg pain. Preoperative demographic and in hours (18.7±18 vs. 4.6±19.1, p<0.01), higher direct cost in USD radiographic outcomes were similar between the two groups. Both ($68,365±$17,863 vs. $50,277±$13,905, p<0.01), and increased groups demonstrated significant improvement in ODI, VAS-Back postoperative day 0 inpatient OME use (36.2±21.9 vs. 12±19, and VAS-leg at 1-year postoperatively. On multivariate analysis p<0.01). There was no no significant difference in case length, there were differences in ODI at 1-year, 1-year back pain, and EBL, LOS, foley duration, days to solid food and 30-day readmission 1-year leg pain between groups with those who initially presented (p>0.05). with leg pain having a lower ODI, VAS Back, and VAS leg. Patients CONCLUSIONS: Skeletally immature idiopathic scoliosis patients who presented with predominantly leg pain were more likely to who undergo TALPT have equivalent two-year revision rates to meet MCID criteria for ODI and VAS-back compared to those with PSF patients However, TALPT had significantly increased ICU stay, predominantly back pain. inpatient OME use on postoperative day 0 and direct cost. Proceedings 78

FDA DEVICE/DRUG STATUS: This abstract does not discuss or P36. What concomitant injuries must the spinal include any applicable devices or drugs. surgeon take into account in the severely injured patient? An analysis of 12,596 patients of the ePosters: Trauma TraumaRegister DGU Jakob Hax, MD1; Till Berk, MD2; Kai Oliver Jensen, MD3; Sascha P35. The difference of union rate of early-stage Halvachizadeh, MD4; Henrik Teuber, DO5; Teresa Di Primio, MD3; 3 5 spondylolysis among each affected lumbar spinal Roman Pfeifer, MD ; Kai Sprengel, MD level in young athletes 1Schulthess Clinic, Zurich, Switzerland; 2University Hospital Zurich, Department of Trauamtologie, Zurich, Zurich, Switzerland; Akihiro Nagamachi, MD, PhD1; Ayaka Hashimoto, MD1; Masatoshi 3University Hospital Zurich - Department of Trauma, Zürich, Morimoto, MD2; Koichi Sairyo, MD, PhD3 Switzerland; 4Zurich, Switzerland; 5University Hospital Zürich, 1Takamatsu Municipal Hospital, Takamatsu, Japan; 2Kuramoto, Zürich, Switzerland Japan; 3Tokushima University, Tokushima, Japan BACKGROUND CONTEXT: There is a lack of studies, with larger BACKGROUND CONTEXT: Virkki reported that there was no case numbers, investigating the prevalence of spinal column significant difference of union rates of spondylolysis between injuries occurring in severely injured patients. For the care strategy L5 and the other lumbar spinal levels. However, there were very of these injuries, it is important to know the type, distribution few reports about union rate of early stage spondylolysis of each and severity of concomitant injuries. Due to the severity of a affected lumbar spinal level, therefor it is not well known about that. concomitant injury, the immediate care of the spinal column PURPOSE: The purpose of this prospective study was to clarify the injuries can be deferred. difference of union rate of early stage spondylolysis among each PURPOSE: Data from the German TraumaRegister DGU® (TR- affected lumbar spinal level in young athletes. DGU) of the German Trauma Society (Deutsche Gesellschaft fuer STUDY DESIGN/SETTING: Prospective observational study. Unfallchirurgie, DGU) was analyzed to show the incidence and PATIENT SAMPLE: Forty young athletes with early stage lumbar distribution of injuries as well as the time of care (early within the spondylolysis participated in this study. There were 34 male and first 48 hours and late after 48 hours) with focus on spine injuries. 6 female. Their mean age was 15 years ranged from 9 to 18 years. STUDY DESIGN/SETTING: Retrospective trauma database All athletes were diagnosed as early stage lumbar spondylolysis by analysis. Included were patients from European hospitals with MRI at the first visit. They also underwent computed tomography at an Injury Severity Score (ISS) >/= 16 and an age >/= 16 years. the first visit to determine their stage and 3 months later to observe Furthermore, the collective was restricted to severe spinal injuries bone union at fractured pars interarticularis. with an Abbreviated Injury Scale (AIS) of 3-6 points. All plexus METHODS: We recommended them to interrupt sports activity and injuries were excluded. In the resulting population, an evaluation of wear a hard orthosis during at least 3 months to treat spondylolysis. the different concomitant injuries with AIS of 2-6 points was then Twenty-four athletes (accepted group) accepted and followed performed in relation to the height segments of the spine (cervical our protocol, however 16 athletes (refused group) refused our spine, thoracic spine, lumbar spine). recommendation because of their competition schedule. Refused PATIENT SAMPLE: A examination of 179,846 patients, who were group continued sports activities without a hard orthosis depended registered in the TR-DGU during 2008 and 2017, was performed. on the degree of their symptom. Spondylolysis was observed 3 OUTCOME MEASURES: The descriptive presentation was cases at L3, 6 cases at L4 and 15 cases at L5 in accepted group at performed using mean value, standard deviation and percentage of the first visit. Spondylolysis was observed 1 case at L3, 8 cases at the total collective. L4 and 7 cases at L5 in refused group at the first visit. Union rates METHODS: The TraumaRegister DGU® (TR-DGU) of the DGU was of each affected lumbar spinal level on computed tomogram were utilized. Data are collected prospectively in four consecutive time calculated in both groups. phases from the site of the accident until discharge from hospital: RESULTS: Union rates of L3, L4 and L5 was 100%, 83.3% and (A) pre-hospital phase, (B) emergency room and initial surgery, 80.0%, respectively, in accepted group. Union rates of L3, L4 and (C) intensive care unit and (D) discharge. The documentation L5 were 0%, 75% and 14.3%, respectively, in refused group. There includes detailed information on demographics, injury pattern, was no statistically significant difference of union rate among comorbidities, pre- and in-hospital management, course on affected lumbar spinal levels in accepted group, however, union intensive care unit, relevant laboratory findings including data on rate of L4 was significantly higher than that of L5 in refused group transfusion and outcome of each individual. The inclusion criteria (chi-square test p<0.0403). are admission to hospital via emergency room with subsequent CONCLUSIONS: Union rates of early stage spondylolysis of each ICU/ICM care, or hospital arrival with vital signs and death affected lumbar spinal level were more than 80% and significant before admission to ICU. The participating hospitals submit their difference was not observed among affected lumbar spinal level in data pseudonymized into a central data-base via a Web-based accepted group. However, that of L4 was significantly higher than application. Scientific data analysis is approved according to a peer that of L5 in refused group. Tezuka reported variations in arterial review procedure laid down in the publication guideline of TR-DGU. supply to the lower lumbar spine. From L1 to L4, each segmental The participating hospitals are primarily located in Germany (90%), artery was identified bilaterally in more than 90% of subjects, but a rising number of hospitals of other countries contribute data but it was identified in less than 10% of subjects at L5. Smaller as well. amount of blood supply for L5 posterior element may be a factor RESULTS: In the generated patient population, 12,596 patients of lower union rate. Surprisingly, union rate of L4 in refused group showed a spine injury. 72.7% were male and 94.4% suffered was 75% without proper treatment. It suggests that sports doctors blunt trauma. On average, the patients were 50.88 +/- 20.2 years allow some athletes with early stage L4 spondylolysis who must old. The most frequent accident mechanisms were car accidents participate their competition to continue sports activity. (19.2%) and motorcycle accidents (12.7%). The overall mortality FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. Proceedings 79

rate was 17%. When reviewing the height segments of the spinal internal database of our hospital. The control group consisted of 40 column, 39.7% of spinal injuries occurred in the cervical spine, adult and 42 pediatric non-pathological second cervical vertebrae 37% in the thoracic and 30.7% in the lumbar spine. In the group of specimens from the collections of the Institute of Anatomy, First injuries with an AIS 3, almost 50% of the patients presented a more Faculty of Medicine, Charles University in Prague. severe injury on another part of the body. Accompanying severe METHODS: We measured the dimension of the dens at the level head injuries (AIS 5) occurred mainly in connection with cervical of the inferior edge of the anterior arch of the atlas in the sagittal spine injuries (11.5%). An accumulation of severe thoracic injuries (a) and coronal (b) planes; the dimension of the dens base in the (AIS 5) was found with injuries of the thoracic spine (14.7%). Using coronal plane (c); the dimension of the C2 vertebral body in the the example of the moderate cervical spine injury (AIS 3), it was sagittal plane (d); the distance between the center of the base shown, that only 15.2% of the patients were treated early in the of the C2 vertebral body and the apex of the dnes (e); the angle presence of more severe concomitant injuries with a higher AIS. included by the line of the posterior–inferior edge of C2 and However, if the cervical spine injury was leading, 35.1% of patients the posterior–superior edge of the dnes (PDAA - posterior dens received early treatment. angulation angle); and the angle included by the line of the C2 CONCLUSIONS: The critically injured patients included in the base and the line connecting the anterior–inferior edge of C2 and study often had a severe spinal injury. An anatomical connection of apex of dens (SIA - screwinsertion angle). These measurements the concomitant injuries could be shown with regard to the height were applied to all radiological and anatomical assessments. The segment of the spinal column. The time of surgical treatment of values measured were then used to calculate means and standard the spine seems to depend on the severity of the concomitant deviations. Statistical comparison of all values was based on non- injuries in the data presented. In everyday clinical practice, the parametric tests, with the level of significance set at 0.05 in all concomitant injuries should be considered in a standardized calculations. manner when determining the time of spinal column treatment. RESULTS: The pediatric cohort was divided into 7 age categories: All aspects should be evaluated in order to establish a priority 0–1, 1–2, 2–3, 3–4, 4–6, 7–9, 10–12, 13–15, 16–18 years. Our orientated treatment plan. results show an increase in all dimensions of the dens with age in FDA DEVICE/DRUG STATUS: This abstract does not discuss or children. In patients < 6 years, these dimension are greater in boys, include any applicable devices or drugs. in the 7–9-year age category the values are almost equal, at the age between 10 and 12 years, greater dimensions are shown by girls and the age category of 13 and more years is dominated boys. P37. Anatomy of the dens and its implications for In adults, we observed a significant gender difference with higher fracture treatment: An anatomical and radiological mean values achieved in males, regardless of the measurement study performed on either CT scans or specimens. Differences between males and females were statistically significant (p < 0.05) in a, c, 1 1 2 Gabor Geri, MD ; Lucie Salavcová, MD ; Jan Štulík, MD ; Michal d and e values. Concerning PDAA, the angulation of the dens is 3 4 Barna, MD ; Ondřej Naňka, MD, PhD similarly age dependent. In infants and the youngest children, the 1Department of Spinal Surgery, First Faculty of Medicine, Charles dens shows a slight anterior angulation with the mean PDAA values University and University Hospital Motol, Prague, Czech Republic; exceeding 180 degrees. However, the shape of the dens gradually 2Klinika spondylochirurgie 1.LF a FN MOTOL, Prague, Prague 5, transforms into posterior angulation as early as between 4 and 6 Czech Republic; 3FN Motol, Prague, Czech Republic; 4Institute of years of age. With increasing age, the angle measured in children Anatomy, First Faculty of Medicine, Charles University, Prague 2, is reduced to values found in adults. When measured on CT scans, Czech Republic the mean PDAA was 162.7 degrees in males and 160.26 degrees in females; the mean SIA was 62.0 degrees in males and 60.2 BACKGROUND CONTEXT: Odontoid fractures are common degrees in females. On specimens, the mean PDAA was 169.47 injuries of the upper cervical spine in both children and adult degrees in males and 166.95 degrees in females; the mean SIA patients. In younger children, this injury typically present through was 65.42 degrees in males and 64.47 degrees in females. the synchrondrosis between the odontoid process and the body of CONCLUSIONS: During growth, there occur changes in all the C2 vertebra. Direct osteosynthesis of the dens with one or two dimensions of the axis that should be respected in evaluation of screws is a popular method of treatment of such injuries, however, imaging studies and treatment of concurrent injuries. Based on adequate fixation might be difficult to achieve in cases with our results, the anatomy of the odontoid process allows insertion abnormal or developing anatomy of the axis. It is currently unknown of two 3.5 mm screws as early as from the age of 1 year, except for what are the precise anatomical and radiological dimensions of the cases with pronounced anatomical anomalies. In adult patients, dens in respect to fracture treatment among all age groups. all dimensions of the dens in respect to size and angulation were PURPOSE: We hypothesize, that a profound knowledge of a normal greater in males than females in both anatomical and radiological anatomical angulation and dimensions of the dens in individual measurements. PDAA should be measured and considered during age categories may contribute to a better understanding of the reduction of displaced dens fractures in all patient populations. complex terrain of the craniocervical junction, particularly in FDA DEVICE/DRUG STATUS: This abstract does not discuss or small children. To address this, we aimed to answer the following include any applicable devices or drugs. questions:1/ at what age is the size of the dens adequate at all levels to accommodate two screws,2/ what is the posterior dens angulation angle (PDAA) in a healthy child and adult,3/ when does the angulation occur? STUDY DESIGN/SETTING: Retrospective analysis of prospectively collected anatomical and radiological data. PATIENT SAMPLE: Consecutive series of 100 adult and 203 pediatric patients aged < 18 years with a complete CT reconstruction of the craniocervical junction, identified in the Author Index 80

Abbas, Aazad: P14 Doita, Minoru: P4 Kanzaki, Koji: 26 Abe, Yuichiro: 32, P27, P28 Duan, Ping G.: P17 Karim, Muhammad Tahir: P12, P30 Abid, Shehar Yar: P12, P30 Elder, Benjamin D.: 2, 3, 63, P23 Katsuura, Yoshihiro: 60, 61, P32 Abudouaini, Haimiti: 4 Elysee, Jonathan: 46 Katyal, Toshali: 45, P34 Ahn, Henry: P14 Emerson, Blaze: 42 Katz, Austen: P5, P20 Aidlen, Jessica P.: 16, P10, P11 Emori, Haruka: 26 Kawaguchi, Yoshiharu: 1 Ajmi, Qasim S.: 17, P25 Endo, Hirooki: P4 Kaye, Ian D.: 2, 3, P23 Albert, Todd J.: P19 Errico, Thomas J.: 42 Kelly, Michael P.: 43 Ali, Shahid: P12, P30 Farooqi, Ali: 57 Kepler, Christopher K.: 3, P23 Allahabadi, Sachin: 45, P34 Fatemi, Parastou: P6 Kim, Han Jo: 46 Alluri, Ram K.: P33 Fehlings, Michael G.: 19, 20 Kim, Ho-Joong: P15, P16 Anderson, Paul A.: 37, 65 Finkelstein, Joel A.: P14 Kimura, Atsushi: 8 Arima, Hideyuki: 47 Fogarty, Casey A.: 53 Kiridly, Daniel: P9 Bae, Hyun W.: 36 Fogel, Harold A.: 54 KOBAYASHI, YUTO: 55 Bakhsheshian, Joshua: 12 Foley, Kevin T.: 22 Koda, Masao: 8 Banno, Tomohiro: 47 Freedman, Brett A.: 2, 3, 63, P23 Kolz, Joshua: 2, 51 Barber, Sean M.: P26 Fukushima, Masayoshi: P29 Kudo, Yoshifumi: 26, 27 Barna, Michal: P37 Furuya, Takeo: 8 Kwon, Byung-Taek: P15, P16 Beall, Douglas P.: 40 Gang, Catherine Himo: 9, 46, 58, 60, 61, Kwon, Ohsang: P15, P16 Berk, Till: P36 P32, P33 Lafage, Renaud: 46 Bernatz, James T.: 37, 65 Gedman, Marissa: 16, P10, P11 Lafage, Virginie: 46 Berven, Sigurd H.: P17 George, Stephen G.: 42 Lambrechts, Mark: 53 Bhale, Rahul A.: 17, P25 Geri, Gabor: P37 Larouche, Jeremie: P14 Bice, Miranda: 37 Goh, Brian C.: 54 Le Huec, Jean-Charles: 43, P24 Binkley, Neil: 65 Goni, Vijay G.: 21 Leal, Luana: 33 Blumenthal, Scott L.: P9 Grauer, Jonathan N.: P19 Lee, Andrew: 53 Boaro, Alessandro: P13 Guinn, Jeremy: P17 Lee, Byung-Jou: P18 Bono, Christopher M.: 54 Guyer, Richard D.: P9 Lee, Changhee: 39 Bou Monsef, Jad: 3, 63 Hah, Raymond J.: 12 Lee, Jonathan: P26 Bourret, Stéphane: 43, P24 Halvachizadeh, Sascha: P36 Lee, Ryan: 60, 61 Bovonratwet, Patawut: P19 Ham, Dae-Woong: P15, P16 Lenke, Lawrence G.: 43 Bowles, Daniel R.: 3 Hanish, Stefan: 53 LeRoy, Taryn E.: 16, P10, P11 Bruggeman, Adam: 36 Hanna, George: 36 Leung, Christopher: 30, P6 Burch, Shane: 33, P17 Hasegawa, Kazuhiro: 43 Lightsey, Harry M.: 35, P3 Burkus, J. Kenneth: 40 Hashimoto, Ayaka: P35 Liu, John C.: 12 Buser, Zorica: 12 Hashizume, Hiroshi: 5, 28 Liu, Limin: 25 Bydon, Mohamad: 3, P23 Hax, Jakob: P36 Logan, Andrew: 11, 41 Carson, Tyler: 22 He, Junbo: P8 Lord, Elizabeth L.: 13, 39 Cerpa, Meghan: 43 Hershman, Stuart H.: 54 Lotan, Raphael: 64 Cha, Thomas D.: 54 Hey, Hwee Weng Dennis: 43 Louie, Philip: 60, 61 Chaudhary, Chirag: 60, 61 HIndoyan, Kevork: P17 Luong, Marilan: 18 Chen, Aaron: P19 Hirase, Takashi: 14 Malacon, Karen: 30 Chen, Clark J.: 13 Hori, Yusuke: 6, 55 Malhotra, Neil: 57 Cherian, Nathan: 53 Hoshino, Masatoshi: 6, 29, 55 Manabe, Hiroaki: 34 Chiba, Yusuke: P4 Hoshino, Yushi: 26, 27 Manning, Blaine: 53 Chikawa, Takashi: 34 Houdek, Matthew: 51 Mansour, Ali: 42 Cho, Robert: 18 Hoyer, Daniel: 22 Maruyama, Hiroshi: 26, 27 Choma, Theodore J.: 53 Hsieh, Patrick C.: 12 Masashi, Takaso: 8 Chou, Dean: P17 Hsiue, Peter P.: 13 Massicotte, Eric M.: P21 Chung, Chloe: 22 Huang, Chengyi: 10 Matsumoto, Morio: 44, 8 Chung, Edward H.: 36 Hur, Jung-Woo: 59, P22 Matsuoka, Akira: 26, 27 Clarke, Michelle J.: 51 Imagama, Shiro: 8 Matsuyama, Yukihiro: 47 Cloche, Thibault: P24 Inagaki, Katsunori: 27 McAnany, Steven J.: 58 Crawford, Alexander: 35, 54, P3 Inoue, Gen: 8 McCarthy, Michael H.: 60, 61 Cummins, Daniel D.: 52 ISHIKAWA, KOJI: 26, 27 McGowan, Brian: 37 Currier, Bradford L.: 2, 3, 63, P23 Ito, Manabu: 56 Mesfin, Fassil B.: 53 Das, Avilash: P25 Iturriaga, Cesar: P5, P20 Metz, Lionel N.: 11, 41 Davis, Timothy T.: 40 Jensen, Kai Oliver: P36 Mihara, Yuki: 47 Desai, Atman: P6 Jivanelli, Bridget: 9 Mihas, Alexander: 42 Devana, Sai: 39 Job, Alan: P5, P20 Mikula, Anthony L.: 65, P23 Di Primio, Teresa: P36 Johnson, Paul J.: 37 Minamide, Akihito: 5 Diab, Mohammad: 45, P34 Kaito, Takashi: P32 Mirza, Muhammad Z.: 53 DiAngelo, Denis J.: 22 Kakadiya, Ghanshyam: 48, P1 Miyagi, Masayuki: 8 Author Index 81

Mok, Jung: 58 Schwab, Frank J.: 46 Wu, Hao-Hua: 11, 41, 45, P17, P34 Moon, Andrew S.: 16, P10, P11 Schwab, Joseph H.: 54 Xi, Zhuo: P17 Moore, Don K.: 53 Sebastian, Arjun S.: 2, 3, 63, P23 Xiong, Ashley: 3, 63, P23 Morimoto, Masatoshi: 34, P35 Shah, Akash A.: 39 Xiong, Grace: 35, P3 Morse, Kyle W.: P33 Shahrestani, Shane: 12 Yabu, Akito: 6 Moufid, Abdollah Y.: P24 Sharma, Ayush: P2 Yacoubian, Vahe: 16 Murakami, Hideki: P4 Sheha, Evan: 58, P32, P33 Yagi, Mitsuru: 44 Nagamachi, Akihiro: P35 Shellock, Jessica: P9 Yamabe, Daisuke: P4 Nagata, Kosei: 15 Shirahata, Toshiyuki: 26 Yamada, Hiroshi: 5, 28, 49 Nagoshi, Narihito: 8, 44 Simpson, Andrew: 5, 35, P3 Yamada, Kentaro: 29, 32, P27, P28 Nakamura, Hiroaki: 6, 29, 32, 55, P27, P28 Siu, Jeremy: 45, P34 Yamamura, Ryo: 27 Nakamura, Masaya: 44 Sklar, Matthew: 30 Yamashita, Kazuta: 34 Nakashima, Daisuke: 31 Slosar, Paul J.: 36 Yamato, Yu: 47 Nakashima, Hiroaki: 8 Song, Yueming: 25 Yamazaki, Masashi: 8 Naňka, Ondřej: P37 SooHoo, Nelson: 39 Yanagisawa, Yoshikazu: 38 Nassr, Ahmad N.: 2, 3, 63, P23 Sprengel, Kai: P36 Yang, Xi: 25 Neufeld, Eric: P5, P20 Stavrakis, Alexandra: 13 Yao, Yu-Cheng: 46 Ng, Terence: P5, P20 Stavrev, Vladimir P.: 62 Yaszemski, Michael J.: 51 Nohara, Yutaka: 5 Stephan, Stephen: 18 Yee, Albert J.: P14 Nori, Satoshi: 44 Striano, Brendan: 35, 54, P3 Yoshida, Go: 47 Oe, Shin: 47 Štulík, Jan: P37 Yoshii, Toshitaka: 8 Ohnmeiss, Donna D.: P9 Suzuki, Akinobu: 6, 29, 55 Yoshimizu, Takaki: 50 Oikawa, Ryosuke: P4 Suzuki, Satoshi: 44 Yoshimura, Noriko: 28 Oka, Hiroyuki: 28 Takahashi, Shinji: 6, 29, 55 Yoshizaki, Hidekazu: 56 Okada, Ejiiro: 44 Takeshita, Katsushi: 8 Yukawa, Yasutsugu: 5 Okano, Ichiro: 26, 27 Tamai, Hidenobu: 28 Zhang, De-An: 18 Okawa, Atsushi: 8 Tamai, Koji: 6, 29, 55 Zhu, Ce: 25 Ondeck, Nathaniel T.: P19 Tannoury, Chadi: 17, P25 Zigler, Jack E.: P9 Oshima, Yasushi: 15 Tannoury, Tony: 17, P25 Zygourakis, Corinna: 30, P6 Oshita, Yusuke: 26, 27 Temple, H Thomas: 40 Otsuka, Seiji: P31 Teraguchi, Masatoshi: 28 Park, Don Y.: 13, 39 Terai, Hidetomi: 6, 29, 55 Park, Jin Hoon: P18 Teuber, Henrik: P36 Park, Jiwon: P15, P16 Tezuka, Fumitake: 34 Pfeifer, Roman: P36 Theologis, Alexander A.: 52 Pinter, Zachariah: 2, 3, 63, P23 Tobert, Daniel G.: 54 Pipkin, William: 24 Tomkins-Lane, Christy C.: P6 Poon, Selina: 18 tong, elizabeth: 30 Qureshi, Sheeraz A.: 9, 46, 58, 60, 61, P19, Toor, Jay: P14 P32, P33 Toyoda, Hiromitsu: 6, 29, 55 Ramchandran, Subaraman: 42 Toyone, Tomoaki: 26, 27 Ratliff, John: 30 Tsuji, Osahiko: 44 Rawat, Suryanshi: 53 Upfill-Brown, Alexander: 39 Retzky, Julia: P19 Urakawa, Hikari: 9, 46, 58, P32 Rivera, Joshua: P17 Vaccaro, Alexander R.: 2, 3, 20 Rogerson, Ashley L.: 16, P10, P11 Vaishnav, Avani S.: 9, 46, 58, 60, 61, P32, P33 Rose, Peter: 51 Vallabhaneni, Ahdarsh: 53 Saade, Aziz: 17, P25 Verma, Rohit B.: P5, P20 Saggi, Satvir: 45, P34 Virk, Sohrab: P32, P33 Sairyo, Koichi: 34, P35 Wada, Shuntaro: P4 Sakai, Toshinori: 34 Wadhwa, Harsh: 30, P6 Salavcová, Lucie: P37 Wagner, Scott: 2, 3, P23 Salmons, Harold I.: 2, P23 Wang, Jeffrey C.: 12 Samartzis, Dino: 28 Wang, Tzong-Jing Victor: 56 Sambhariya, Varun: 24 Watanabe, Kota: 44 Samuel, Andre: P19 Watanabe, Masahiko: 23 Sardar, Zeeshan: 43 Wellings, Elizabeth: 51 Sarig Bahat, Hilla: P7 Williams, Seth K.: 37, 65 Sasaki, Kanji: 50 Wilson, Jamie R.: 19, 20, P21 Sato, Kosuke: 9, 46, P32 Wilson, Jefferson: 19, 20 Schaffler, Ben: P5, P20 Winzenried, Alec: 65 Schoenfeld, Andrew J.: 35, P3 Wood, Addison R.: 24 Schroeder, Gregory D.: 2 Wright, Steven: 11, 41 Disclosure Index 82

Range Key Shares, 1%); Research Support (Staff and/or materials): Level A: $100 to $1000 Halyard (D), Medtronic (D), Mesoblast (F), Relievant (F), Sollis Level B: $1,001 to $10,000 Phamaceuticals (D), Vivex (None); Scientific Advisory Board: Level C: $10,001 to $25,000 Medtronic (C); Speaking and/or Teaching Arrangements: Level D: $25,001 to $50,000 Medtronic (C), Vertiflex (Travel Expense Reimbursement); Stock Level E: $50,001 to $100,000 Ownership: Eleven Biotherapeutics (None), Flow Forward (None), Level F: $100,001 to $500,000 Metactive (None), Radius Pharmaceuticals (None), Sophiris Bio Level G: $500,001 to $1M (None), Spinetech (None), Sway Inc (None). Level H: $1,000,001 to $2.5M Berven, Sigurd H.: Consulting: Innovasis (B), Integrity Spine Level I: Greater than $2.5M (B), Medicrea (C), Medtronic (C); Fellowship Support: Globus Medical (D); Grants: AOSpine (E, Paid directly to institution/ Abitbol, Jean-Jacques: Consulting: Nanovis (C); Royalties: Globus employer), Globus (D, Paid directly to institution/employer); Medical (C), Nanovis (B); Scientific Advisory Board: St. Theresa Private Investments: Green Sun Medical (50,000 Shares, <1%); Medical (Advisory only); Stock Ownership: St. Teresa Medical Royalties: Stryker (F); Scientific Advisory Board: Globus Medical (<1%). (Stock options); Speaking and/or Teaching Arrangements: Aidlen, Jessica P.: Consulting: NuVasive (C), Zimmer Biomet (B). Medtronic (B), Stryker Spine (B); Stock Ownership: Globus Albert, Todd J.: Board of Directors: American Orthopaedic Medical (25,000 Shares, <1%), Providence Medical (2,500 Shares, Association (Nonfinancial, Treasurer-Elect), Hospital For Special <1%); Trips/Travel: Scoliosis Research Society (Travel Expense Surgery (None, Surgeon-in-Chief Emeritus and Medical Director), Reimbursement, Paid directly to institution/employer). Scoliosis Research Society (Nonfinancial, Past President); Bess, Shay: Consulting: K2M Stryker (B); Grants: DePuy Synthes Consulting: Nuvasive (B); Other: JP Medical Publishers (B), (F, Paid directly to institution/employer), Globus Medical (E, Paid Saunders/Mosby- Elsevier (B), Springer (A), Thieme Medical directly to institution/employer), Medtronic (F, Paid directly to Publishers (B); Research Support (Staff and/or materials): institution/employer), NuVasive (F, Paid directly to institution/ PCORI (D); Royalties: DePuy Synthes Spine (F); Stock Ownership: employer), SeaSpine (E, Paid directly to institution/employer), ASIP (D), Augmedics (F), Biomerix (D, 42,253 Shares), Bonovo SI-BONE (D, Paid directly to institution/employer); Research Orthopedics (D, 85,737 Shares), Crosstrees Medical (D, <1%), Support (Staff and/or materials): International Spine Study Group Cytodyn Inc. (F), Gentis (D), Innovative Surgical Designs (F), Foundation (B); Royalties: NuVasive (B), Stryker (E). InVivo Therapeutics (C, <1%. Advisory Board, Stock options.), Binkley, Neil: Consulting: Amgen (B); Research Support (Staff and/ Invuity (C, <1%. Member of Advisory Board, stock options.), or materials): Radius (F, Paid directly to institution/employer). Morphogenesis (E), Paradigm Spine, LLC (F, <1%.), Physician Blumenthal, Scott L.: Consulting: Aesculap (C), Bayliss Medical (C), Recommended Nutriceuticals (D), PMIG (D), Pulse Equity (F), Orthofix (None), Sites Medical (None), Vertera (None); Device or Spinicity (D, <1%.), Strathspey Crown (F), Surg.IO (E), Vital 5 Biologic Distribution Group (Physician-Owned Distributorship): (None, <1%. Advisory Board, Stock Holder), Zimmer Biomet (F). Aesculap (A); Scientific Advisory Board: Aesculap (B), Fziomed Alluri, Ram K.: Stock Ownership: Medtronic (B), Stryker (B), Zimmer (None), Vertiflex (B); Speaking and/or Teaching Arrangements: (B). Aesculap (D), Bayliss (None), Vertiflex (B); Stock Ownership: Anderson, Paul A.: Consulting: Amgen (C), Medtronic (B), Radius Centinel Spine (1%), Fziomed (1%), Vertiflex (1%). Medical (B); Device or Biologic Distribution Group (Physician- Bono, Christopher M.: Consulting: United Health Care (B); Other: Owned Distributorship): Pioneer/RTI (B); Stock Ownership: Titan The Spine Journal (NASS) (F); Royalties: Elsevier (B), Wolters Surgical (1%). Kluwer (A). Arnold, Paul M.: Board of Directors: AANS/CNS Joint Section Brooks, Nathaniel P.: Other: NASS (Nonfinancial, NASS Section on On Neurotrauma (Nonfinancial), CSRS (Nonfinancial), LSRS Minimally Invasive Procedures Chair). (Nonfinancial), Spineex (1%); Research Support (Staff and/ Bruggeman, Adam: Consulting: K2M (B), Medtronic (B), Nexxt or materials): Evoke Medical, (40%, Paid directly to institution/ Spine (Future Compensation Expected), NovaBone (Future employer). Compensation Expected), Prosidyan Spine (B, Outside 12-Month Bae, Hyun W.: Board of Directors: Prosidyan (Stock); Consulting: Requirement), SI-BONE (C); Scientific Advisory Board: Titan Spine Stryker (C); Device or Biologic Distribution Group (Physician- (E, Outside 12-Month Requirement). Owned Distributorship): Biomet (B), NuVasive (D), Stryker (D), Burch, Shane: Consulting: MEDTRONIC (D), Zimmer Biomet (C); Zimmer (B); Grants: Medtronic (E); Research Support (Staff and/ Fellowship Support: AOSpine (D), Globus (E, Paid directly to or materials): Empirical Spine (F, Paid directly to institution/ institution/employer), NuVasive (D, Paid directly to institution/ employer), Mesoblast (F, Paid directly to institution/employer), employer); Grants: MISONIX (A); Speaking and/or Teaching Orthorebirth USA Rebossis (E, Outside 12-Month Requirement, Arrangements: Medtronic (F), MISONIX, (A). Paid directly to institution/employer), Pfizer (E, Paid directly to Burkus, J. Kenneth: Consulting: NuVasive (C, Outside 12-Month institution/employer), Simplify (E, Paid directly to institution/ Requirement), Vivex (B); Royalties: Zimmer Biomet (E). employer), Zyga (B, Paid directly to institution/employer); Buser, Zorica: Board of Directors: LSRS (Nonfinancial, Co-chair Scientific Advisory Board: Difusion (Stock), Spinal Restoration of Research Committee); Consulting: AOSpine (B, Outside (Stock); Speaking and/or Teaching Arrangements: Synthes (C). 12-Month Requirement), Cerapedics (B), The Scripps Research Beall, Douglas P.: Board of Directors: Nocimed (Nonfinancial), Institute (Future Compensation Expected), Xenco Medical (B, Vexed (C); Consulting: Imaging3 (D), IZI (Nonfinancial), Johnson Outside 12-Month Requirement); Research Support (Staff and/ & Johnson (None), Lilly (D), Medical Metrics (Travel Expense or materials): Motion Metrix (B, Paid directly to institution/ Reimbursement), Medlantis (Travel Expense Reimbursement), employer), Next Science (F, Paid directly to institution/employer), Merit Medical (Travel Expense Reimbursement), Peterson SeaSpine (F, Outside 12-Month Requirement, Paid directly to Enterprises (Travel Expense Reimbursement), Simplify institution/employer); Trips/Travel: AOSpine (Travel Expense Medical (Travel Expense Reimbursement), Spineology (Travel Reimbursement), NASS (Travel Expense Reimbursement). Expense Reimbursement), Stryker (C), Techlamed (Travel Carson, Tyler: Consulting: GS Medical (Future Compensation Expense Reimbursement); Private Investments: Vexed (10,000 Expected), Nexxt Spine (B), TDI (D); Private Investments: Amplify Disclosure Index 83

Surgical (Future Compensation Expected). Dagenais, Simon: Consulting: US Spine And Sport Foundation Cha, Thomas D.: Consulting: Bio2 (B), Bio2 (B), GE Healthcare (B), (B); Other: Vertex Pharmaceuticals (Salary); Royalties: Elsevier NuVasive (C), NuVasive (B), Stryker (B); Fellowship Support: (A); Speaking and/or Teaching Arrangements: Drug Information AOSpine (F, Paid directly to institution/employer), K2M (F, Association (A). Paid directly to institution/employer), OREF (F, Paid directly to Dailey, Andrew T.: Royalties: Biomet/Zimmer/Lanx (D, institution/employer), NuVasive (E, Paid directly to institution/ Development of cervical fusion device); Consulting: K2M employer); Grants: North American Spine Society (D, Paid directly (Financial, Grant support. 100,000, Paid directly to institution/ to institution/employer); Research Support (Investigator Salary): employer); Speaking and/or Teaching Arrangements: Medtronic Donoghue Foundation (B, Paid directly to institution/employer), (Financial, Consulting; 8000); Research Support - Staff and/or Gordon and Betty Moore Foundation (B, Paid directly to Materials: K2M (E, Grant for FEM project developed through the institution/employer); Research Support (Staff and/or materials): Dept of Bioengineering at the University of Utah, Paid directly National Institute Of Health (E, Paid directly to institution/ to institution/employer); Relationships Outside the One-Year employer). Requirement: Biomet (2008-15, Royalties, E, Development of a Chiba, Kazuhiro: Board of Directors: Cervical Spine Research cervical fusion device). Society Asia Pacific Section (Board of Directors), Japanese Davis, Timothy T.: Private Investments: Alpha Diagnostics Orthopedic Association (Council Member), Japanese Society (10,000 Shares, 100%), ATAI Life Sciences (1,000 Shares, <1%), for Spine Surgery and Related Research (Council Member); Beckley Psytech (1,000 Shares, <1%), Compass Pathways Consulting: General Insurance Rating Organization of Japan (19,605 Shares), Forever Labs (1,000 Shares, <1%), Paradigm (Salary), Health Insurance Claims Review & Reimbursement Spine (1,000 Shares, <1%), Petehealth (1,000 Shares, <1%), Services (Salary), Japan International Cooperation Agency Prosydian (1,000 Shares, <1%), Source Surgery Center (100%); (Salary), Seikagaku Co, Ltd. (B, Paid directly to institution/ Research Support (Staff and/or materials): DiscGenics (D), employer); Grants: Asahikasei Pharma Corp. (B, Paid directly to Kolon Tissuegene (D), Vivex (D); Speaking and/or Teaching institution/employer), Astellas Pharma Inc. (B, Paid directly to Arrangements: Abbott Neuromodulation (C), Boston institution/employer), Chugai Pharmaceutical Co., Ltd. (B, Paid Scientific (D); Trips/Travel: Abbott Neuromodulation (Travel directly to institution/employer), Daiichi-Sankyo Co. Ltd. (B, Paid Expense Reimbursement), Boston Scientific (Travel Expense directly to institution/employer), Eisai Co., Ltd. (C, Paid directly Reimbursement). to institution/employer), Eli Lilly Japan K.K (B, Paid directly to Desai, Atman: Consulting: DePuy Synthes (B), Stryker (B). institution/employer), Kaken Pharmaceutical Co. Ltd. (B, Paid Devin, Clinton J.: Consulting: Stryker Spine (F, Paid directly to directly to institution/employer), Medtronic Sofamore Danek (B, institution/employer); Other: Medtronic Expert Witness (E, Paid directly to institution/employer), Ministry of Health Labor Outside 12-Month Requirement); Research Support (Staff and/or and Welfare of Japan (C, Science Research Grant), Nippon Zoki materials): Stryker Spine (E, Paid directly to institution/employer); Pharmaceutical Co. Ltd (B, Paid directly to institution/employer), Scientific Advisory Board: Wright Medical (None, Research Pfeizer Japan Inc. (B, Paid directly to institution/employer), design); Stock Ownership: Balanced Back (B, 105 Shares, 100%). Seikagaku Corporation (B, Paid directly to institution/employer), DeVine, John G.: Consulting: Spinal Elements (B), StartBox (A), Shionogi & Co., Ltd. (B, Paid directly to institution/employer), Ulrich (D); Speaking and/or Teaching Arrangements: AOSpine Smith & Nephew (B, Paid directly to institution/employer), Taisho North America (B). Pharmaceutical Co. Ltd (B, Paid directly to institution/employer), Diab, Mohammad: Scientific Advisory Board: Auctus (Nonfinancial, Teijin Pharma Ltd. (B, Paid directly to institution/employer), <2%); Stock Ownership: JAZBI (<1%). Zimmer Biomet (C, Paid directly to institution/employer). DiAngelo, Denis J.: Grants: Centinel Spine (F, Outside 12-Month Cho, Robert: Consulting: DePuy Synthes (C), NuVasive (E), Requirement, Paid directly to institution/employer); Stock Orthopediatrics (C); Scientific Advisory Board: ErgoBaby Inc. Ownership: Cagenix (199,000 Shares, 7.26%). (Medical Advisory Board, B). Dohring, Edward J.: Board of Directors: NASS (Travel Expense Choinski, Sabina: Other: North American Spine Society (Salary). Reimbursement, First Vice President); Other Office: AAOS (Travel Choma, Theodore J.: Consulting: Medtronic Inc (B); Speaking and/ Expense Reimbursement); Private Investments: Anzu (<1%). or Teaching Arrangements: AOSpine North America (B); Stock Elder, Benjamin D.: Consulting: DePuy Synthes (None); Scientific Ownership: Gentis, Inc (20,000 Shares, <1%). Advisory Board: Injectsense (Future Compensation Expected). Chou, Dean: Board of Directors: Lumbar Spine Research Society Enix, Dennis E.: Grants: U.S. Department of Health and Human (None); Consulting: Globus (D), Medtronic (B); Royalties: Globus Services (H, Outside 12-Month Requirement, Paid directly to (D). institution/employer). Chung, Chloe: Research Support (Staff and/or materials): Errico, Thomas J.: Board of Directors: Harms Study Group Medtronic (Salary). (None); Device or Biologic Distribution Group (Physician-Owned Chung, Edward H.: Consulting: Prosidyan (C, <1%, Paid directly to Distributorship): Fastenetix (D, Outside 12-Month Requirement); institution/employer). Grants: NIH via WashU (B, Outside 12-Month Requirement, Paid Chutkan, Norman B.: Device or Biologic Distribution Group directly to institution/employer); Research Support (Staff and/ (Physician-Owned Distributorship): Globus Medical (C); Speaking or materials): Pfizer (D, Outside 12-Month Requirement, Paid and/or Teaching Arrangements: AO North America (Travel directly to institution/employer); Royalties: K2M/Stryker (F); Expense Reimbursement). Speaking and/or Teaching Arrangements: K2M/Stryker (Travel Cunningham, Bryan W.: Research Support (Staff and/or materials): Expense Reimbursement); Trips/Travel: K2M/Stryker (C). Medi-Launch, Inc. (C, Paid directly to institution/employer). Erwin, William Mark: Board of Directors: Notogen (Stock options Currier, Bradford L.: Fellowship Support: AOSpine North America and salary support only); Grants: Skoll Family Trust (G, Paid (E, Paid directly to institution/employer); Private Investments: directly to institution/employer); Research Support (Investigator Spinology (1%), Tenex (310,000 Shares, 1%); Royalties: DePuy Salary): Canadian Chiropractic Research Foundation (D); Spine (D, Paid directly to institution/employer), Wolters Kluwer Research Support (Staff and/or materials): Skoll Family Trust (A), Zimmer Biomet (F, Paid directly to institution/employer). (F, Outside 12 month requirement, Paid directly to institution/ employer); Scientific Advisory Board: Notogen (Stock options Disclosure Index 84

only); Stock Ownership: Notogen (3,000,000 Shares, 33%). Society (None), Lumbar Spine Research Society (None), North Ferrara, Lisa A.: Consulting: OrthoKinetic Technologies (Salary, American Spine Society (None); Consulting: Asahi (B), Medtronic Paid directly to institution/employer); Scientific Advisory Board: (C), Wright Medical (C); Device or Biologic Distribution Group 4Web (<1%), Diamond Orthopedics (Salary, Paid directly to (Physician-Owned Distributorship): Stryker (F); Scientific Advisory institution/employer). Board: Bioventus (C); Trips/Travel: Medtronic (B), Micromedicine Finkelstein, Joel A.: Fellowship Support: Stryker Canada (E, Paid (A), Stryker (B). directly to institution/employer), Zimmer Biomet (D, Paid directly Ito, Manabu: Board of Directors: AO Foundation (C), Japanese to institution/employer). Scoliosis Society (Nonfinancial), The Japanese Society For Spine Foley, Kevin T.: Board of Directors: DiscGenics (None), MERI Surgery And Related Research (Nonfinancial), The Japanese (None); Consulting: Medtronic (C); Private Investments: Spinal Instrumentation Society (Nonfinancial). DiscGenics (672,000 Shares, 13%), SpineWave (753,000 Shares); Johnson, Claire: Board of Directors: NCMIC (D); Other: Brighthall Royalties: Medtronic (I); Stock Ownership: Medtronic (None, (B), Global Spine Care Initiative (None, Outside 12-Month 44,000 Shares), NuVasive (30,000 Shares, H). Requirement). France, John C.: Board of Directors: AONA (B). Katsuura, Yoshihiro: Stock Ownership: Moderna (<1%). Francis, Todd B.: Speaking and/or Teaching Arrangements: Kaye, Ian D.: Consulting: Camber Spine (Travel Expense NuVasive (B). Reimbursement). Freedman, Brett A.: Grants: US Government - DoD (I); Private Kelly, Michael P.: Fellowship Support: AOSpine (E, Paid directly Investments: JM Shuler Medical, Inc. (45%); Speaking and/ to institution/employer); Other: The Journal of Bone and or Teaching Arrangements: Medtronic (B, Outside 12-Month Joint Surgery (B); Research Support (Staff and/or materials): Requirement). DePuy/Synthes Spine (B, Paid directly to institution/employer), Gandhi, Anand A.: Private Investments: Lung Institute Dallas International Spine Study Group Foundation (B, Paid directly to (Owner). institution/employer), Setting Scoliosis Straight Foundation (B, Ghiselli, Gary: Board of Directors: Colorado Orthopedic Society Paid directly to institution/employer). (None); Consulting: Johnson & Johnson (C); Device or Biologic Kepler, Christopher K.: Grants: NIH (I, Paid directly to institution/ Distribution Group (Physician-Owned Distributorship): Impulse employer); Other Office: Clinical Spine Surgery (Nonfinancial); Neuromonitoring, Neurointerpretive Services (E), New Era Research Support (Staff and/or materials): CSRS (D, Paid directly Orthopedics (B). to institution/employer), RTI (C, Paid directly to institution/ Ghogawala, Zoher: Board of Directors: Cervical Spine Research employer); Royalties: Inion (None). Society (Nonfinancial, Chair, Research Committee Director, CSRS Kim, Han Jo: Board of Directors: AOSpine (B); Fellowship Support: Registry), GN2.0-Nidus (18,750 Shares, 66%), Joint Spine Section AOSpine (D, Paid directly to institution/employer); Research - AANS-CNS (Nonfinancial, Spine Section Chair). Support (Staff and/or materials): ISSGF (C, Paid directly to Gidvani, Sandeep N.: Other: AAOS (AAOS International Committee institution/employer); Royalties: K2M (D), Zimmer Biomet (F). Member); Private Investments: Spinal Balance (Promissory Kim, Jin-Sung L.: Board of Directors: ISESS (Nonfinancial), SMISS Note). Asia Pacific (Nonfinancial); Consulting: Elliquence (B), RIWO Gilliland-Johnson, Meagan: Other Office: North American Spine Spine (B); Grants: AOSpine (A); Other: Global Spine Journal Society (Salary). (Nonfinancial, Deputy Editor); Scientific Advisory Board: Amplify Grauer, Jonathan N.: Board of Directors: LSRS (Nonfinancial, Surgical (None). committee/board role); Other: NASS (D). Klineberg, Eric O.: Consulting: DePuy (C), Stryker (C); Fellowship Guyer, Richard D.: Consulting: Aescalup (C), Orthofix (D), Spinal Support: AOSpine (E, Paid directly to institution/employer); Kinetics (B); Royalties: Atec (B), Nanovis (D), Stryker - K2M (B). Speaking and/or Teaching Arrangements: AOSpine (C), Hah, Raymond J.: Consulting: NuVasive (D). Medtronic/Medicrea (C). Haro, Hirotaka: Consulting: Asahikasei Pharma (B, Paid directly to Knight, Reginald Q.: Consulting: Stryker Spine (B), Vertebral institution/employer); Grants: Stryker Japan (C). Technology Inc (B), Vertera (F, Outside 12-Month Requirement). Hershman, Stuart H.: Consulting: DePuy Synthes Spine (B); Kreiner, Scott: Research Support (Staff and/or materials): Abbott Fellowship Support: NuVasive (E, Paid directly to institution/ (Future Compensation Expected, Paid directly to institution/ employer); Speaking and/or Teaching Arrangements: DePuy employer); Speaking and/or Teaching Arrangements: Spine Synthes Spine (B), NuVasive (B); Trips/Travel: DePuy Synthes Intervention Society (Travel Expense Reimbursement). Spine (B). Lafage, Renaud: Stock Ownership: Nemaris (<1%). Hilibrand, Alan S.: Board of Directors: AAOS (Treasurer, Travel Lafage, Virginie: Consulting: Globus Medical (E); Research Support expenses); Private Investments: Paradigm Spine ($10,000 (Staff and/or materials): International Spine Study Group (F, investment); Royalties: Amedica (C), Biomet Spine (F); Stock Paid directly to institution/employer); Royalties: NuVasive (B); Ownership: Amedica (20,000 Shares, <1%), Spinal Ventures (3%). Scientific Advisory Board: International Spine Study Group Hipp, John A.: Consulting: Medical Metrics (A, Paid directly to (Nonfinancial); Speaking and/or Teaching Arrangements: DePuy institution/employer); Other Office: Medical Metrics (Salary); Synthes (C), Implanet (B, Outside 12-Month Requirement). Stock Ownership: Medical Metrics (593,445 Shares, 8%, Lawrence, Brandon D.: Board of Directors: AO Spine North America Scientific Founder and Chief Scientist). (Nonfinancial, Paid directly to institution/employer), Cervical Hisey, Michael S.: Consulting: Zimmer Biomet Spine (D); Private Spine Research Society (Nonfinancial, Paid directly to institution/ Investments: Medical Venture Fund (1 Share, <1%); Royalties: employer); Fellowship Support: AO Spine North America (E, Paid Zimmer Biomet Spine (B); Scientific Advisory Board: Innovasis directly to institution/employer); Trips/Travel: AO Spine North (A); Speaking and/or Teaching Arrangements: Zimmer Biomet America (B, Paid directly to institution/employer). (Travel Expense Reimbursement). Le Huec, Jean-Charles: Consulting: Medtronic (B); Scientific Hoyer, Daniel: Other Office: Medtronic (Salary). Advisory Board: Hyprevention (Nonfinancial); Stock Ownership: Hsieh, Patrick C.: Royalties: Medtronics (D), Nuvasive (C), Zimmer Hyprevention (0.20%). Biomet (B). Lenke, Lawrence G.: Consulting: Abryx (B), EOS TECHNOLOGY Hsu, Wellington K.: Board of Directors: Cervical Spine Research (None), Medtronic (F, monies donated to a charitable Disclosure Index 85

foundation, Outside 12-Month Requirement); Grants: Fox Family Foundation (Salary). Foundation (A), Scoliosis Research Society (D, Travel expenses, Okawa, Atsushi: Device or Biologic Distribution Group (Physician- Paid directly to institution/employer); Other: AOSpine (D, Travel Owned Distributorship): Medtronic Sfomar Danek (A). expenses, Paid directly to institution/employer; Broadwater (B, Park, Don Y.: Consulting: NuVasive, Inc (B), SeaSpine (B), Stryker Travel expenses); Research Support (Staff and/or materials): (B); Other: Globus (B). Adult Symptomatic Lumbar Scoliosis (B, Paid directly to Park, Paul: Consulting: Globus Medical (C), NuVasive (D); Grants: institution/employer), Complex CADS ISSG (E, Paid directly to DePuy (B, Outside 12-Month Requirement, Paid directly to institution/employer), Confirm S2AI Screw Placement By Routine institution/employer), ISSG (B, Paid directly to institution/ Fluoroscopy (B, Paid directly to institution/employer), EOS employer); Royalties: Globus Medical (E). Imaging (A, Paid directly to institution/employer), Fox Pediatric Pearson, Adam M.: Grants: OREF (F, Paid directly to institution/ Spinal Deformity Study (A, Paid directly to institution/employer), employer). Scoliosis Outcome Database Registry (A, Paid directly to Phillips, Frank M.: Board of Directors: Edge Surgical (None), institution/employer), Scoli-Risk-1 (B, Paid directly to institution/ ISASS (Nonfinancial), SMISS (Nonfinancial), Surgio (None), employer), Tropical Application Of Tranexamic Acid To Reduce Theracell (5.00%); Consulting: Augmedics (None), SI Bone (C), Blood Loss In Spine Surgery (E, Paid directly to institution/ Spinal Kinetics/Orthofix (C), Spinal Simplicity (None), Stryker employer); Royalties: Medtronic (I), Quality Medical Publishing (D); Royalties: Medtronic (B), Nuvasive (G); Stock Ownership: (A); Trips/Travel: AOSpine (B), Broadwater (B). Nuvasive (Future Compensation Expected), Vertiflex (G). Liu, John C.: Consulting: Viseon (None); Trips/Travel: NASS (Travel Poon, Selina: Speaking and/or Teaching Arrangements: Stryker (B, Expense Reimbursement). Outside 12-Month Requirement). Logan, Andrew: Other: Sensivision Health Technologies Prasad, Ravi: Scientific Advisory Board: Bicycle Health (Stock (Nonfinancial, Co-founder). options, Outside 12-Month Requirement). Lotan, Raphael: Consulting: Augmedics Inc. (2%), Epidutech Inc. Prather, Heidi: Other: AAPM&R (Salary, Senior Editor for the PM&R (5%). journal, Paid directly to institution/employer). Matsumoto, Morio: Research Support (Staff and/or materials): Przybylski, Gregory J.: Other: Cigna (Salary, Medical Director, Medtronic Japan (D, Paid directly to institution/employer), salary), Eli Research (B); Private Investments: Cyberknife (C); NuVasive (D, Paid directly to institution/employer), Zimmer Trips/Travel: AANS (B). Biomet (F, Paid directly to institution/employer); Scientific Qureshi, Sheeraz A.: Board of Directors: Society Of Minimally Advisory Board: Kyocera (A). Invasive Spine Surgery (Nonfinancial); Consulting: Globus Mayer, E. Kano A.: Consulting: Turning Point (Future Medical, Inc. (D), Paradigm Spine (None, Outside 12-Month Compensation Expected); Other: Wharton, Levin, Ehrmantraut Requirement), Stryker K2M (C); Other Office: Annals Of & Klein, P.A (B, Outside 12 month Requirement); Private Translational Medicine (Nonfinancial, Editorial Board Member), Investments: Lanai Health Solutions (30.00%); Speaking and/or Association Of Bone And Joint Surgeons (Nonfinancial, Teaching Arrangements: North America Spine Society (B); Stock Committee Member), Cervical Spine Research Society Ownership: Infinite Orthopedics (1%); Trips/Travel: AMA (Travel (Nonfinancial), Contemporary Spine Surgery (Nonfinancial, Expense Reimbursement). Editorial Board Member), International Society For The McAnany, Steven J.: Consulting: Medtronic (C), Zimmer Biomet Advancement Of Spine Surgery (Nonfinancial, Committee (B). Member, 2021 Annual Conference Program Co-Chair), Lumbar Mehta, Hitesh P.: Consulting: Stealth Startup (C). Spine Research Society (Nonfinancial), Minimally Invasive Spine Metz, Lionel N.: Consulting: Evolution Spine (D); Royalties: Study Group (Nonfinancial, Board Member), North American Evolution Spine (D). Spine Society (Nonfinancial, Committee Member), Simplify Mikhael, Mark M.: Consulting: Clariance Spine (B), GS Medical (B). Medical, Inc. (B, Clinical Events Committee Member), Society Mroz, Thomas E.: Royalties: Stryker (F). Of Minimally Invasive Spine Surgery (Nonfinancial, Committee Murphy, Donald R.: Consulting: University Of Pittsburgh (C); Member, Board Member); Private Investments: Tissue Royalties: CRISP Education And Research (D); Stock Ownership: Differentiation Intelligence (D), Vital 5 (E, Outside 12-Month Platform Support Services (19%), Primary Spine Provider Requirement); Royalties: Globus Medical, Inc. (A), Stryker K2M Network (19%), Spine Care Partners (19%). (None); Scientific Advisory Board: Healthgrades (None, Outside Nakashima, Daisuke: Board of Directors: Grace Imaging Inc., (C, 12-Month Requirement), Lifelink.Com Inc. (None), Spinal 56%, Paid directly to institution/employer). Simplicity, LLC (None); Speaking and/or Teaching Arrangements: Nassr, Ahmad N.: Consulting: DePuy (B, Outside 12-Month Amopportunities (None), Globus Medical, Inc. (None), RTI Requirement); Fellowship Support: AOSpine NA (E, Paid Surgical Inc. (None); Trips/Travel: Globus Medical, Inc. (B), directly to institution/employer); Research Support (Staff and/ Integrity Implants Inc (A), Medical Device Business Services (A), or materials): Pfizer (F, Paid directly to institution/employer), Medtronic USA, Inc. (A), NuVasive, Inc. (B), Paradigm Spine (A), Premia Spine (E, Paid directly to institution/employer). Stryker K2M (C). Neuman, Brian J.: Grants: DePuy Synthes (C, Paid directly to Ratliff, John: Consulting: Medtronic (B), NuVasive (B), Styker institution/employer); Other: ISSGF (Research support); Speaking Spine (C); Grants: AHRQ (E, Outside 12-Month Requirement, and/or Teaching Arrangements: Medtronic (B, Paid directly to Paid directly to institution/employer); Other Office: AANS/CNS institution/employer). (Nonfinancial). O’Brien, Colleen: Other Office: North American Spine Society Reitman, Charles A.: Board of Directors: NASS (Travel Expense (Salary). Reimbursement); Other: NASS (Nonfinancial, Committeee Oe, Shin: Consulting: Medtronik Sofamor Danek Inc. (D, Paid leadership); Scientific Advisory Board: Clinical Orthopaedics And directly to institution/employer); Endowments: Meitoku Related Research (B, Paid directly to institution/employer). Medical Institution Jyuzen Memorial Hospital (E, Paid directly Riew, K. Daniel: Board of Directors: Global Spine Journal to institution/employer); Other Office: Japan Medical Dynamic (Nonfinancial), NASS (Nonfinancial); Consulting: Biomet (None), Marketing Inc. (E, Paid directly to institution/employer). Happe Spine (Future Compensation Expected), Medtronic (I); Ohnmeiss, Donna D.: Other: Texas Back Institute Research Royalties: Biomet (F); Speaking and/or Teaching Arrangements: Disclosure Index 86

Biomet (C), Medtronic (Travel Expense Reimbursement); Stock Simpson, Andrew: Board of Directors: Vertebrx (Nonfinancial, 50%). Ownership: Amedica (B), Axiomed (E), Benvenue (C), Expanding Skolasky, Richard L.: Board of Directors: North American Spine Orthopedics (<1%), Osprey (1% options), Paradigm Spine (B), Society (Nonfinancial, Governance Committee Chair, Research Spinal Kinetics (E), Spineology (B, <1%), Vertiflex (B); Trips/Travel: Program Management Chair); Other: International Society For DePuy Synthes (C). Quality Of Life Research (Nonfinancial, Associate Editor). Rose, Peter: Consulting: K2M (B, Paid directly to institution/ Slosar, Paul J.: Consulting: Medtronic (C), Prosidyan (B); Royalties: employer); Speaking and/or Teaching Arrangements: DePuy (B); Titan Spine (F). Trips/Travel: K2M (Travel Expense Reimbursement). Smith, Justin S.: Consulting: Carlsmed (None), Cerapedics (B), Russell, Robb: Trips/Travel: Shanghai University of Traditional DePuy Synthes (C), K2M/Stryker (B), NuVasive (D), Zimmer Chinese Medicine (Travel Expense Reimbursement, Outside Biomet (C); Fellowship Support: AOSpine (E, Fellowship support, 12-Month Requirement). Paid directly to institution/employer); Grants: DePuy Synthes (C, Sakai, Daisuke: Research Support (Staff and/or materials): TUNZ Paid directly to institution/employer); Research Support (Staff Pharma (Nonfinancial); Scientific Advisory Board: TUNZ Pharma and/or materials): NuVasive (D, Paid directly to institution/ (Salary). employer); Royalties: NuVasive (B), Thieme (A), Zimmer Biomet Samartzis, Dino: Board of Directors: AOSpine (C), Global Spine (F); Stock Ownership: Alphatec (G), NuVasive (C). Journal, European Spine Journal (Nonfinancial, Deputy Editor, Spiker, W. Ryan: Consulting: Biomet / Zimmer (B); Fellowship Global Spine Journal Executive Editorial Board, European Spine Support: AOSpine / DePuy Synthes (D, Paid directly to institution/ Journal). employer). Sardar, Zeeshan: Speaking and/or Teaching Arrangements: Sprengel, Kai: Board of Directors: German Trauma Society Medtronic (B), Stryker Spine (C, Outside 12-Month Requirement). (Nonfinancial); Fellowship Support: NuVasive (B, Outside Sasaki, Kanji: Consulting: Medacta International (C, Paid directly to 12-Month Requirement); Research Support (Staff and/ institution/employer). or materials): CarboFix Orthopedics (A, Outside 12-Month Schaefer, Briana: Other: North American Spine Society (Salary). Requirement), DePuy (A, Outside 12-Month Requirement), Schneider, Byron J.: Consulting: AIM Specialty (B), State Farm Medtronic (A, Outside 12-Month Requirement); Scientific (C); Grants: SIS (E, Paid directly to institution/employer); Advisory Board: Committee On Emergency Medicine, Intensive Speaking and/or Teaching Arrangements: AAPM (Travel Care And Trauma Management Of The German Trauma Society Expense Reimbursement), NASS (A, Travel, Reimbursement, and (Nonfinancial), Medtronic (Nonfinancial, Outside 12-Month Honorarium for speaking/teaching). Requirement), Stryker (Nonfinancial, Outside 12-Month Schneider, Michael J.: Consulting: NCMIC Inc. (B), State Farm Requirement); Speaking and/or Teaching Arrangements: Insurance (C); Grants: NIH (F, Paid directly to institution/ Medtronic (B, Paid directly to institution/employer), Stöckli employer); Research Support (Investigator Salary): NIH (D, Paid Medical (B, Outside 12-Month Requirement). directly to institution/employer). Steinmetz, Michael P.: Board of Directors: AANS/CNS Section on Schoenfeld, Andrew J.: Grants: Department of Defense (D, Disorders of the Spine (Exhibits Committee Chair), Council of Paid directly to institution/employer), NIH (F, Paid directly to State Neurosurgical Societies (Vice Chair); Consulting: Globus institution/employer), OREF (F, Paid directly to institution/ (B), Stryker Spine (B); Device or Biologic Distribution Group employer); Other Office: Journal of Bone and Joint Surgery (Physician-Owned Distributorship): Biomet Spine (B); Speaking (E); Royalties: Springer Publishers (A, Outside 12-Month and/or Teaching Arrangements: Stryker (B). Requirement), Wolters Kluwer, Springer (B). Su, Brian W.: Device or Biologic Distributorship (Physician-Owned Schroeder, Gregory D.: Board of Directors: CSRS, Clinical Spine Distributorship): Stryker (C); Consulting: Gentis (C); Scientific Surgery (Nonfinancial); Consulting: Zimmer (C), Stryker (C), Advisory Board: LINK (C); Research Support - Staff and/or Advanced Medical (C), Medtronic (C); Royalties: Astura (Future Materials: Marin General Hospital Foundation (E). Compensation Expected); Trips/Travel: AOSpine (C). Sullivan, William J.: Board of Directors: NASS (Executive Schultz, Brittany: Other: North American Spine Society (Salary). Committee); Trips/Travel: NASS (B, Travel Expense Schwab, Frank J.: Board of Directors: International Spine Study Reimbursement). Group (Nonfinancial); Consulting: Globus (E), K2M (B, Outside Suzuki, Akinobu: Speaking and/or Teaching Arrangements: 12-Month Requirement), Zimmer Biomet (D); Grants: DePuy Asahikasei Pharma (A), Shionogi Pharmaceutical (A). Spine (H, Paid directly to institution/employer), K2M (E, Paid Takahata, Masahiko: Grants: Eisai Pharma (B); Research Support directly to institution/employer), NuVasive (E, Paid directly to (Staff and/or materials): Genetechnoscience (C), Medtronic (C). institution/employer), Stryker (D, Paid directly to institution/ Takeshita, Katsushi: Speaking and/or Teaching Arrangements: Eli employer); Private Investments: SeaSpine (None, 30%), VFT Lilly & Company (C, Paid directly to institution/employer), Pfizer (Nonfinancial, 50%); Royalties: Medicrea (C), MSD (F), Zimmer (B, Paid directly to institution/employer), Stryker (B, Paid directly Biomet (F). to institution/employer). Schwab, Joseph H.: Scientific Advisory Board: Chordoma Tannoury, Chadi: Consulting: DePuy J&J (C); Royalties: Wolters- Foundation (Nonfinancial); Speaking and/or Teaching Kluwer Publisher (A); Stock Ownership: 4Web (6,000 Shares). Arrangements: AO Spine (Travel Expense Reimbursement, Tannoury, Tony: Consulting: DePuy (C); Device or Biologic Outside 12-Month Requirement), Stryker Spine (B, Outside Distribution Group (Physician-Owned Distributorship): DePuy 12-Month Requirement). Spine (D); Speaking and/or Teaching Arrangements: DePuy Shellock, Jessica: Consulting: Alphatec (A), Centinel Spine (C), (Consulting Disclosed). SeaSpine (B). Temple, H Thomas: Consulting: Vivex Biologics, Inc (Salary); Other: Shen, Francis H.: Board of Directors: MTF (B); Consulting: DePuy HCA Healthcare, Inc. (Salary); Scientific Advisory Board: My Synthes (C), Medtronic (D), Nuvasive (B); Research Support Medical Images (Nonfinancial), Nova Southeastern University (Staff and/or materials): Medtronic (A); Royalties: Elsevier (B), (Salary); Speaking and/or Teaching Arrangements: Ortho Onkos Globus (D). (None), Stryker (B). Shin, John H.: Consulting: Carbofix (None), Depuy (B), Medtronic Theologis, Alexander A.: Consulting: Alphatec (C), DePuy Spine (A), Nuvasive (B). (B), Intuitive Surgical (B); Other: JBJS (B); Research Support Disclosure Index 87

(Staff and/or materials): Innovasis (C, Paid directly to institution/ Wilson, Jefferson: Consulting: Stryker Canada (C); Grants: employer). AOSpine North America (C, Paid directly to institution/employer), Tomkins-Lane, Christy C.: Grants: Mount Royal University (B); Neurosurgical Research and Education Fund (D, Paid directly to Other: Vivametrica Ltd (Salary); Stock Ownership: Vivametrica institution/employer). Ltd (16%). Wolf, Christina: Other: North American Spine Society (Salary). Truumees, Eeric: Board of Directors: Seton Family of Doctors Woods, Barrett: Consulting: Altus (D, Paid directly to institution/ (None); Other Office: AAOS (Editor-in-Chief of AAOS Now); employer), Precision (B), Titan (D); Speaking and/or Teaching Research Support (Staff and/or materials): Medtronic (C, Paid Arrangements: Stryker (C). directly to institution/employer), Pfizer (E, Outside 12-Month Xiong, Ashley: Research Support (Staff and/or materials): Xenex Requirement, Paid directly to institution/employer), Relievant (None). (F, Paid directly to institution/employer), Seikagaku Corporation Yagi, Mitsuru: Consulting: Johnson & Johnson (B, Paid directly (C, Paid directly to institution/employer), Stryker Spine (B, to institution/employer), Zimmer Biomet (A, Paid directly to Outside 12-Month Requirement, Paid directly to institution/ institution/employer); Device or Biologic Distribution Group employer), Vertex Pharma (D, Outside 12-Month Requirement, (Physician-Owned Distributorship): Medtronic (B, Outside Paid directly to institution/employer); Trips/Travel: AAOS (Travel 12-Month Requirement, Paid directly to institution/employer). Reimbursement (B). Yanagisawa, Yoshikazu: Private Investments: Fukuoka Mirai Vaccaro, Alexander R.: Royalties: Aesculap (None), Atlas Hospital (Nonfinancial, Outside 12-Month Requirement). Spine (B), Elsevier (B), Globus (E), Jaypee (A), Medtronic (E), Yaszemski, Michael J.: Consulting: Medtronic, (B Paid directly to Spinewave (None), Stryker Spine (G), Taylor Francis/Hodder institution/employer). And Stoughton (A), Thieme (B); Stock Ownership: Advanced Yee, Albert J.: Fellowship Support: Zimmer (E, Paid directly to Spinal Intellectual Properties (None), Atlas Spine (None), Avaz institution/employer); Other: Johnson & Johnson (D, Paid directly Surgical (None), Bonovo Orthopaedics (None), Computational to institution/employer), Medtronic (C, Paid directly to institution/ Biodynamics (None), Cytonics (None), Deep Health (None), employer), Stryker (C, Paid directly to institution/employer). Dimension Orthotics LLC (None), ElectroCore (None), Flagship Yu, Elizabeth: Grants: Empirical Spine (E, Paid directly to Surgical (None), Flowpharma (None), Globus (None), Innovative institution/employer); Speaking and/or Teaching Arrangements: Surgical Design (None), Insight Therapeutics (None), Jushi AOSpine (A), DePuy Spine (B). (None), NuVasive (None), Orthobullets (None), Paradigm Spine Zigler, Jack E.: Consulting: Aesculap (D), Centinel Spine (B), (None), Parvizi Surgical Innovation (None), Progressive Spinal FloSpine (B), Medtronic Spine (B), Orthofix (D), Simplify Medical Technologies (None), Replication Medica (None), Spine Medica (B); Royalties: Zimmer Spine (B); Scientific Advisory Board: (None), Spinology (None), Stout Medical (None), Vertiflex (None). Safe Orthopedics (future warrants); Speaking and/or Teaching Verma, Rohit B.: Consulting: Stryker (C, Outside 12-Month Arrangements: (none). Requirement). Zygourakis, Corinna: Consulting: Globus (B), Spine Align PPC (B), Walsh, Kevin M.: Private Investments: Spinalcyte (Future Stryker/K2M (A). Compensation Expected); Speaking and/or Teaching Arrangements: Medtronic (B); Trips/Travel: Stryker (Travel Expense Reimbursement). Wang, Jeffrey C.: Board of Directors: American Orthopaedic Association (Nonfinancial), AO Foundation (C, Travel Expense Reimbursement), Society For Brain Mapping And Theruapeutics (Nonfinancial); Fellowship Support: AO Foundation (E, Paid directly to institution/employer); Private Investments: Bone Biologics (51,255 Shares, 1%), ElectroCore (<1%), PearlDiver (25,000 Shares, 1%), Surgitech (<1%); Royalties: Biomet (F), DePuy Synthes (B), SeaSpine (C). Wang, Michael Y.: Consulting: DePuy Synthes (F), Spineology (C), Stryker (C); Private Investments: Kinesiometrics (None); Speaking and/or Teaching Arrangements: Medtronic (B); Stock Ownership: ISD (1%), Medical Device Partners (1%). Watanabe, Kota: Consulting: Kyocera Corporation (B); Grants: Nippon Zoki Pharmaceutical Co., Ltd. (B); Speaking and/or Teaching Arrangements: DePuy Synthes (B), Medtronic (B). Wetzel, F. Todd: Other: NASS (C, Paid directly to institution/ employer); Stock Ownership: Relievant Medical (40,000 Shares, 1%). Whang, Peter G.: Consulting: Atlas Spine (B), Bio2 (B), Medtronic (D), Orthofix (D), SI-BONE (E), Stryker (C); Other: Cerapedics (B), Empirical Spine (B), Ferring Pharmaceuticals (B), Relievant (C), Simplify Medical (D); Scientific Advisory Board: DiFusion (Travel Expense Reimbursement); Speaking and/or Teaching Arrangements: DePuy Synthes (C). Williams, Seth K.: Consulting: DePuy Synthes Spine (D), Expanding Innovations (A), SeaSpine (B), Stryker Spine (D); Speaking and/ or Teaching Arrangements: AO North America (B, Outside 12-Month Requirement); Stock Ownership: Titan Spine (15,000 Shares). Disclosure Index 88

The following participants have Nothing to Disclose:

Abbas, Aazad Hax, Jakob McGowan, Brian Siu, Jeremy Abe, Yuichiro He, Junbo Mesfin, Fassil B. Sklar, Matthew Abid, Shehar Yar Hey, Hwee Weng Dennis Mhaidli, Hani H. Song, Yueming Abudouaini, Haimiti HIndoyan, Kevork Mihara, Yuki SooHoo, Nelson Ahn, Henry Hirase, Takashi Mihas, Alexander Stavrakis, Alexandra Ajmi, Qasim S. Hori, Yusuke Mikula, Anthony L. Stavrev, Vladimir P. Ali, Shahid Hoshino, Masatoshi Minamide, Akihito Stephan, Stephen Allahabadi, Sachin Hoshino, Yushi Mirza, Muhammad Z. Steyn, Chris Arima, Hideyuki Houdek, Matthew Miyagi, Masayuki Striano, Brendan Bakhsheshian, Joshua Hsiue, Peter P. Mok, Jung Štulík, Jan Banno, Tomohiro Huang, Chengyi Molter, Michael W. Suri, Pradeep Barber, Sean M. Hur, Jung-Woo Moon, Andrew S. Suzuki, Satoshi Barna, Michal Imagama, Shiro Moore, Don K. Takahashi, Shinji Benny, Benoy V. Inagaki, Katsunori Morimoto, Masatoshi Tamai, Hidenobu Berk, Till Inoue, Gen Morse, Kyle W. Tamai, Koji Bernatz, James T. Ishii, Ken Moufid, Abdollah Y. Teraguchi, Masatoshi Bhale, Rahul A. Ishikawa, Koji Murakami, Hideki Terai, Hidetomi Bice, Miranda Iturriaga, Cesar Nagamachi, Akihiro Teuber, Henrik Boaro, Alessandro Jallo, Jack Nagata, Kosei Tezuka, Fumitake Bou Monsef, Jad Jensen, Kai Oliver Nagoshi, Narihito Tobert, Daniel G. Bourret, Stéphane Jivanelli, Bridget Nakamura, Hiroaki Tong, Elizabeth Bovonratwet, Patawut Job, Alan Nakamura, Masaya Toor, Jay Bowles, Daniel R. Johnson, Paul J. Nakashima, Hiroaki Toyoda, Hiromitsu Buchl, Eric H. Kaito, Takashi Naňka, Ondřej Toyone, Tomoaki Bydon, Mohamad Kakadiya, Ghanshyam Neufeld, Eric Tsuji, Osahiko Cerpa, Meghan Kanzaki, Koji Ng, Terence Upfill-Brown, Alexander Chaudhary, Chirag Karim, Muhammad Tahir Nohara, Yutaka Urakawa, Hikari Chen, Aaron Katyal, Toshali Nori, Satoshi Vaishnav, Avani S. Chen, Clark J. Katz, Austen O'Brien, David Reese Vallabhaneni, Ahdarsh Cherian, Nathan Kawaguchi, Yoshiharu Ohtori, Seiji Vira, Shaleen N. Chiba, Yusuke Kim, Ho-Joong Oikawa, Ryosuke Virk, Sohrab Chikawa, Takashi Kimura, Atsushi Oka, Hiroyuki Wada, Shuntaro Clarke, Michelle J. Kiridly, Daniel Okada, Ejiiro Wadhwa, Harsh Cloche, Thibault Kobayashi, Yuto Okano, Ichiro Wagner, Scott Crawford, Alexander Koda, Masao Ondeck, Nathaniel T. Wang, Tzong-Jing Victor Cummins, Daniel D. Kolz, Joshua Oshima, Yasushi Watanabe, Masahiko Das, Avilash Kudo, Yoshifumi Oshita, Yusuke Wellings, Elizabeth Devana, Sai Kwon, Byung-Taek Otsuka, Seiji Whitcomb, Gregory L. Di Primio, Teresa Kwon, Ohsang Pangarkar, Sanjog Wilson, Jamie R. Doita, Minoru Lahey, Donna M. Park, Jin Hoon Winzenried, Alec Duan, Ping G. Lambrechts, Mark Park, Jiwon Witiw, Christopher Ehsanian, Reza Larouche, Jeremie Pfeifer, Roman Wood, Addison R. Elysee, Jonathan Leal, Luana Pinter, Zachariah Wright, Steven Emerson, Blaze Lee, Andrew Pipkin, William Wu, Hao-Hua Emori, Haruka Lee, Bryan S Placide, Rick J. Xi, Zhuo Endo, Hirooki Lee, Byung-Jou Ramchandran, Subaraman Xiong, Grace Farooqi, Ali Lee, Changhee Rawat, Suryanshi Yabu, Akito Fatemi, Parastou Lee, Jonathan Retzky, Julia Yacoubian, Vahe Fehlings, Michael G. Lee, Ryan Rivera, Joshua Yamabe, Daisuke Finkenberg, John G LeRoy, Taryn E. Rogerson, Ashley L. Yamada, Hiroshi Fogarty, Casey A. Leung, Christopher Saade, Aziz Yamada, Kentaro Fogel, Harold A. Lightsey, Harry M. Saggi, Satvir Yamamura, Ryo Fukushima, Masayoshi Lin, Clifford Sairyo, Koichi Yamashita, Kazuta Furuya, Takeo Liu, Limin Sakai, Toshinori Yamato, Yu Gang, Catherine Himo Long, William D Salavcová, Lucie Yamazaki, Masashi Gedman, Marissa Lord, Elizabeth L. Salmons, Harold I. Yang, Xi George, Stephen G. Louie, Philip Sambhariya, Varun Yao, Yu-Cheng Geri, Gabor Luong, Marilan Samuel, Andre Yoshida, Go Goh, Brian C. Malacon, Karen Thomas, Santhosh A. Yoshii, Toshitaka Gong, Gary Xin Malhotra, Neil Sarig Bahat, Hilla Yoshimizu, Takaki Goni, Vijay G. Manabe, Hiroaki Sato, Kosuke Yoshimura, Noriko Guinn, Jeremy Manning, Blaine Schaffler, Ben Yoshizaki, Hidekazu Halvachizadeh, Sascha Mansour, Ali Sebastian, Arjun S. Yukawa, Yasutsugu Ham, Dae-Woong Maruyama, Hiroshi Shah, Akash A. Zhang, De-An Hanish, Stefan Masashi, Takaso Shahrestani, Shane Zhu, Ce Hanna, George Massicotte, Eric M. Sharma, Ayush Hasegawa, Kazuhiro Matsuoka, Akira Sheha, Evan Hashimoto, Ayaka Matsuyama, Yukihiro Shirahata, Toshiyuki Hashizume, Hiroshi McCarthy, Michael H. Simon, Jeremy Ian