Is Spinal Fusion Surgery Overused?

Total Page:16

File Type:pdf, Size:1020Kb

Is Spinal Fusion Surgery Overused? OR Manager Vol. 20 No. 4 April 2004 Is spinal fusion surgery overused? ost spinal fusion surgery is being done without clear evidence that it benefits patients, according to an opinion piece in the Feb 12 New MEngland Journal of Medicine. About 75% of spinal fusions now are done for reasons such as disk disorders that are beyond the original indications and aren’t backed by enough research. The authors conclude the costly procedure may be overused. The annual number of spinal fusions has been rising rapidly—by 77% between 1996 and 2001—compared with 13% to 14% for hip and knee replacements. Expensive spinal implants like pedicle Numbers of spinal fusion, knee arthroplasty, screws and cages, which can add thousands of and hip replacement in the US dollars to a case, also have been introduced without much in the way of research, accord- ing to Richard A. Deyo, MD, professor of med- 450,000 icine at the University of Washington, Seattle, 400,000 and his colleagues. 350,000 Knee arthroplasty 300,000 Time to step back? 250,000 Hip replacement “It seems that it’s appropriate to step back (total and partial) 200,000 and ask, ‘Is it really wise to be using instru- 150,000 mentation as routinely as we do,’ if we can’t Spinal fusion demonstrate any benefit to patients in terms of No. of operations 100,000 pain relief or function, and if the costs are high- 50,000 er and the complications are higher,” Dr Deyo 0 1993 1994 1995 1996 1997 1998 1999 2000 2001 told OR Manager. One example is instrumented and noninstru- Data are from the Agency for Healthcare Research and Quality. mented fusions. Though several randomized tri- Source: Deyo R A et al. N Engl J Med. Feb 12, 2004; 350: 722-726. Copyright © 2004. als show instrumented fusions had a slightly Massachusetts Medical Society. All rights reserved. higher rate of solid fusions, “It’s not clear at all that they result in any better pain relief or patient functioning,” he said. “And in most cases, the use of implants seems to be associat- ed with more complications.” As evidence that spinal fusions are overused, the authors point to wide varia- tions in use of the procedure around the country—in New England rates vary 10- fold from one place to another, according to a 1995 report—rapidly rising rates of surgery, high rates of reoperation, and high rates of complications. If evidence-based practice was followed, spinal fusion might be reserved for spondylolisthesis and only rarely performed for disk herniation or spinal stenosis with spondylolisthesis, they say. Recommendations for change The authors make several recommendations. Among them are better alignment of financial incentives with data on the effi- cacy of fusions and stepped-up regulation by the Food and Drug Admini-stra- tion. On the financial aspects, Dr Deyo said he didn’t have a specific proposal but is concerned “that in a sense surgeons are being paid the best for doing proce- dures where there arguably is the least evidence of benefit for patients.” He noted that spine surgeons have a higher income than other orthopedic and neurosur- geons and that spinal fusions pay better than other types of spinal procedures. The authors also advocate that the FDA require “more rigorous research” on spinal devices before they are introduced; for instance, looking at whether the 1 OR Manager Vol. 20 No. 4 April 2004 devices yield better pain relief and function in addition to a better solid fusion rate. What about new technologies like bone morphogenic protein (BMP)? “I think we need more evidence on these things,” he said. “In the case of BMP, at least there are some randomized trials to support its use, although they are very small trials and relatively short-term. I think it is not so clear what the long- term benefits will be and whether the benefit is worth the cost.” The authors advised similar caution on other new technologies, such as artifi- cial disks, electrothermal therapy, analgesic pumps, and implanted spinal stimu- lators. They also advise caution on new spinal implants like artificial disks. How could their article help value analysis teams in the OR? Dr Deyo said, “Many of the things are probably things people think about and already do to some extent—such as trying to standardize implants as much as possible.” he said. Another suggestion is tougher: looking to see whether surgeons recommend- ing new devices have financial conflicts of interest. “I think it’s worth it—unpleasant though it may be—for a hospital adminis- trator to ask, ‘Is the surgeon getting consulting fees from the company that makes the device? Or is this really a disinterested recommendation?’” ❖ References Deyo R A, Nachemson A, Mirza S K. Spinal-fusion surgery: The case for restraint. N Engl J Med. Feb 12, 2004; 350:722-726. Katz J N. Lumbar spinal fusion: Surgical rates, costs, and complications. Spine. 1995;20:785-835. Kuntz K M, Snider R K, Weinstein J N, et al. Cost-effectiveness of fusion with and without instrumentation for patients with degenerative spondylolisthesis and spinal stenosis. Spine. 2000;25:1132-1139. Copyright © 2004. OR Manager, Inc. All rights reserved. Phone 800/442-9918 or visit www.ormanager.com 2.
Recommended publications
  • Subchondral Bone Regenerative Effect of Two Different Biomaterials in the Same Patient
    Hindawi Publishing Corporation Case Reports in Orthopedics Volume 2013, Article ID 850502, 5 pages http://dx.doi.org/10.1155/2013/850502 Case Report Subchondral Bone Regenerative Effect of Two Different Biomaterials in the Same Patient Marco Cavallo,1 Roberto Buda,2 Francesca Vannini,1 Francesco Castagnini,1 Alberto Ruffilli,1 and Sandro Giannini2 1 IClinic,RizzoliOrthopaedicInstitute,BolognaUniversity,ViaGiulioCesarePupilli1,40136Bologna,Italy 2 Orthopaedics and Traumatology, I Clinic, Rizzoli Orthopaedic Institute, Bologna University, Via Giulio Cesare Pupilli 1, 40136Bologna,Italy Correspondence should be addressed to Marco Cavallo; [email protected] Received 2 May 2013; Accepted 17 June 2013 Academic Editors: E. R. Ahlmann, M. Cadossi, and A. Sakamoto Copyright © 2013 Marco Cavallo et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. This case report aims at highlighting the different effects on subchondral bone regeneration of two different biomaterials inthe same patient, in addition to bone marrow derived cell transplantation (BMDCT) in ankle. A 15-year-old boy underwent a first BMDCT on a hyaluronate membrane to treat a deep osteochondral lesion (8 mm). The procedure failed: subchondral bone was still present at MRI. Two years after the first operation, the same procedure was performed on a collagen membrane with DBM filling the defect. After one year, AOFAS score was 100 points, and MRI showed a complete filling of the defect. The T2 mapping MRI after one year showed chondral tissue with values in the range of hyaline cartilage.
    [Show full text]
  • Pain Management & Spine Surgery Procedures
    OrthoNet PPA Code List Pain Management and Spine Surgery Procedures AND Effective 01/01/2018 Major Joint and Foot/ Lower Extremity Procedures (Blue Medicare HMO PPO) CATEGORY PROCCODE PROCEDURE DESCRIPTION Pain Management & Spine Surgery Procedures Spinal Fusion 22510 Perq cervicothoracic inject Spinal Fusion 22511 Perq lumbosacral injection Spinal Fusion 22512 Vertebroplasty addl inject Spinal Fusion 22513 Perq vertebral augmentation Spinal Fusion 22514 Perq vertebral augmentation Spinal Fusion 22515 Perq vertebral augmentation Spinal Fusion 22532 LAT THORAX SPINE FUSION Spinal Fusion 22533 LAT LUMBAR SPINE FUSION Spinal Fusion 22534 LAT THOR/LUMB ADDL SEG Spinal Fusion 22548 NECK SPINE FUSION Spinal Fusion 22551 NECK SPINE FUSE&REMOV BEL C2 Spinal Fusion 22552 ADDL NECK SPINE FUSION Spinal Fusion 22554 NECK SPINE FUSION Spinal Fusion 22556 THORAX SPINE FUSION Spinal Fusion 22558 LUMBAR SPINE FUSION Spinal Fusion 22585 ADDITIONAL SPINAL FUSION Spinal Fusion 22590 SPINE & SKULL SPINAL FUSION Spinal Fusion 22595 NECK SPINAL FUSION Spinal Fusion 22600 NECK SPINE FUSION Spinal Fusion 22610 THORAX SPINE FUSION Spinal Fusion 22612 LUMBAR SPINE FUSION Spinal Fusion 22614 SPINE FUSION, EXTRA SEGMENT Spinal Fusion 22630 LUMBAR SPINE FUSION Spinal Fusion 22632 SPINE FUSION, EXTRA SEGMENT Spinal Fusion 22633 LUMBAR SPINE FUSION COMBINED Spinal Fusion 22634 SPINE FUSION EXTRA SEGMENT Spinal Fusion 22800 FUSION OF SPINE Spinal Fusion 22802 FUSION OF SPINE Spinal Fusion 22804 FUSION OF SPINE Spinal Fusion 22808 FUSION OF SPINE Spinal Fusion 22810 FUSION
    [Show full text]
  • Hounsfield Units on Lumbar Computed Tomography For
    Open Med. 2019; 14: 545-551 Research Article Kyung Joon Kim, Dong Hwan Kim, Jae Il Lee, Byung Kwan Choi, In Ho Han, Kyoung Hyup Nam* Hounsfield Units on Lumbar Computed Tomography for Predicting Regional Bone Mineral Density https://doi.org/10.1515/med-2019-0061 Keywords: Hounsfield Unit; Bone Mineral Density (BMD); received March 28, 2019; accepted June 7, 2019 Dual X-ray absorptiometry (DEXA); Quantitative com- puted tomography (QCT); Osteoporosis Abstract: Objective: Bone mineral density (BMD) is a very important factor in spinal fusion surgery using instrumen- tation. Our aim was to investigate the utility of Hounsfield units (HU) obtained from preoperative lumbar computed tomography (CT) to predict osteoporosis coupling with data of quantitative computed tomography (QCT) and 1 Introduction dual X-ray absorptiometry (DEXA). Bone quality is an important prognostic factor for spinal Methods. We reviewed 180 patients that underwent both fusion with instrumentation. Severe osteoporosis is a sig- QCT and lumbar CT for spine surgery. HU was retrospec- nificant cause of hardware failure such as pedicle screw tively calculated on the lumbar CT of 503 lumbar vertebrae loosening and pull-out after spinal fusion surgery. Thus, from L1 to L3. Femur DEXA was performed in all patients bone mineral density (BMD) is a very important factor in and spine DEXA was tested in 120 patients (331 vertebrae). spinal fusion surgery, and the diagnosis of osteoporosis BMD was grouped as osteoporosis (QCT<80mg/cm3, DEXA before surgery is very important. BMD using dual X-ray T score≤-2.5) and non-osteoporosis (QCT≥80mg/cm3, absorptiometry (DEXA) or quantitative computed tomog- DEXA T score>-2.5) for comparison of HU value.
    [Show full text]
  • Differences Between Subtotal Corpectomy and Laminoplasty for Cervical Spondylotic Myelopathy
    Spinal Cord (2010) 48, 214–220 & 2010 International Spinal Cord Society All rights reserved 1362-4393/10 $32.00 www.nature.com/sc ORIGINAL ARTICLE Differences between subtotal corpectomy and laminoplasty for cervical spondylotic myelopathy S Shibuya1, S Komatsubara1, S Oka2, Y Kanda1, N Arima1 and T Yamamoto1 1Department of Orthopaedic Surgery, School of Medicine, Kagawa University, Kagawa, Japan and 2Oka Orthopaedic and Rehabilitation Clinic, Kagawa, Japan Objective: This study aimed to obtain guidelines for choosing between subtotal corpectomy (SC) and laminoplasty (LP) by analysing the surgical outcomes, radiological changes and problems associated with each surgical modality. Study Design: A retrospective analysis of two interventional case series. Setting: Department of Orthopaedic Surgery, Kagawa University, Japan. Methods: Subjects comprised 34 patients who underwent SC and 49 patients who underwent LP. SC was performed by high-speed drilling to remove vertebral bodies. Autologous strut bone grafting was used. LP was performed as an expansive open-door LP. The level of decompression was from C3 to C7. Clinical evaluations included recovery rate (RR), frequency of C5 root palsy after surgery, re-operation and axial pain. Radiographic assessments included sagittal cervical alignment and bone union. Results: Comparisons between the two groups showed no significant differences in age at surgery, preoperative factors, RR and frequency of C5 palsy. Progression of kyphotic changes, operation time and volumes of blood loss and blood transfusion were significantly greater in the SC (two- or three- level) group. Six patients in the SC group required additional surgery because of pseudoarthrosis, and four patients underwent re-operation because of adjacent level disc degeneration.
    [Show full text]
  • Indications for Fusion Following Decompression for Lumbar Spinal Stenosis
    Neurosurg Focus 3 (2): Article 2, 1997 Indications for fusion following decompression for lumbar spinal stenosis Mark W. Fox, M.D., and Burton M. Onofrio, M.D. Neurosurgery Associates, Limited, St. Paul, Minnesota; and Department of Neurosurgery, The Mayo Clinic, Rochester, Minnesota Degenerative lumbar spinal stenosis is a common condition affecting middle-aged and elderly people. Significant controversy exists concerning the appropriate indications for fusion following decompressive surgery. The purpose of this report is to compare the clinical outcomes of patients who were and were not treated with fusion following decompressive laminectomy for spinal stenosis and to identify whether fusion was beneficial. The authors conclude that patients in whom concomitant fusion procedures were performed fared better than patients who were treated by means of decompression alone when evidence of radiological instability existed preoperatively. Key Words * lumbar spinal stenosis * laminectomy * fusion * indication The decision to perform fusion following decompression for degenerative lumbar spinal stenosis has been studied by many authors.[14,16,30,52,69] Unfortunately, no clear consensus has been reached to determine which patients are most likely to benefit from a concomitant lumbar fusion. Patient satisfaction following lumbar decompression alone ranges from 59 to 96%, with early surgical failures resulting from inadequate decompression and preoperative lumbar instability.[2,4,8,12,21,22,26,29,31,34,65] Late recurrence of back or leg problems may also result from acquired spinal instability. The goal of this study was to analyze clinical outcomes in patients treated with and without fusion following lumbar decompression to determine which patients benefited most. The ability to identify predictive factors for successful surgery with fusion would improve overall clinical results and decrease both early and late failures caused by persistent or acquired spinal instability.
    [Show full text]
  • Lumbar Spinal Fusion (Posterior)
    FACT SHEET FOR PATIENTS AND FAMILIES Lumbar Spinal Fusion (posterior) What is lumbar spinal fusion? Lumbar spinal fusion is a surgery to join two or more Vertebrae spinal bones — called vertebrae [VUR-tuh-brey] — so that they Normal disc eventually grow into one solid bone. Why do I need spinal fusion? Degenerated disc The surgery is usually done to correct instability of the spine. Arthritis, injuries, or simple wear and tear can cause some of the bones in your spine to slip or shift out of place. This abnormal bone movement can cause back pain. It can Instability also pinch nerves, causing pain, numbness, or weakness in your legs. The leg pain is called sciatica [si-AT-i-kuh] or radiculopathy [ruh-dik-yoo-LAH-puh-thee]. Spinal fusion can treat abnormal The goal of spinal fusion is to stop abnormal movement and movement in the spine. thus eliminate pain in your back and legs. Possible benefits Risks and possible complications Alternatives Spinal fusion may There are risks of complication with any surgery. These Spinal fusion surgery eliminate pain by may include complications of the anesthesia, blood loss, is usually done after stopping abnormal infection, and death. Common complications of spinal non-surgical treatment and painful movement fusion are listed below: options have failed. between diseased • Blood loss. With any surgery, there is the potential for These can include: vertebrae. life-threatening blood loss, but with current techniques, • Medicines this is rare. • Physical therapy • Infection (1 or 2 in 100 patients). Even with antibiotics • Traction and careful sterile techniques, there is still a small risk of Spinal injections developing a wound infection.
    [Show full text]
  • Use of Computed Tomography for Assessing Bone Mineral Density
    Neurosurg Focus 37 (1):E4, 2014 ©AANS, 2014 Use of computed tomography for assessing bone mineral density JOSEPH J. SCHREIBER, M.D.,1 PAUL A. ANDERSON, M.D.,2 AND WELLINGTON K. HSU, M.D.3 1Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, New York; 2Department of Orthopedics & Rehabilitation, University of Wisconsin, Madison, Wisconsin; and 3Department of Orthopaedic Surgery, Northwestern University Feinberg School of Medicine, Chicago, Illinois Assessing local bone quality on CT scans with Hounsfield unit (HU) quantification is being used with increasing frequency. Correlations between HU and bone mineral density have been established, and normative data have been defined throughout the spine. Recent investigations have explored the utility of HU values in assessing fracture risk, implant stability, and spinal fusion success. The information provided by a simple HU measurement can alert the treating physician to decreased bone quality, which can be useful in both medically and surgically managing these patients. (http://thejns.org/doi/abs/10.3171/2014.5.FOCUS1483) KEY WORDS • Hounsfield unit • osteoporosis • bone mineral density ITH an aging population, osteoporosis is increas- calculated from a region of interest (ROI) on CT scans ingly becoming a public health concern. Recent without any additional cost or radiation exposure. Values estimates suggest that more than 10 million peo- are calculated based on the following formula: HU = ([m Wple are affected in the US, with an additional 44 million - mw]/mw) × 1000, where m is defined as the linear x-ray 11 citizens at risk. The disease is typically characterized by attenuation coefficient of the selected voxel and mw the an age-related reduction in bone strength that predisposes attenuation coefficient of distilled water at room tempera- affected individuals to low-energy fractures.
    [Show full text]
  • Spinal Fusion
    Spinal Fusion North American Spine Society Public Education Series What Is Spinal Fusion? The spine is made up of a series of bones called “vertebrae”; between each vertebra are strong connective tissues called discs which hold one vertebra to the next and act as cushions. The disc allows for movements of the vertebrae and lets people bend and rotate their neck and back. The type and degree of motion varies between the different levels of the spine: cervical (neck), thoracic (chest) or lumbar (low back). The cervical spine is a highly mobile region that permits movement in all directions. The thoracic spine is much more rigid because of the presence of ribs and is designed to protect the heart and lungs. The lumbar spine allows mostly forward and backward bending movements (flexion and extension). Fusion is a surgical technique in which one or more of the vertebrae of the spine are united together (“fused”) so that motion no longer occurs between them. The concept of fusion is similar to that of welding in industry. Spinal fusion surgery, however, does not weld the vertebrae during surgery. Rather, bone grafts are placed around the spine during surgery. The body then heals the grafts over several months —similar to healing a fracture—which joins, or “welds,” the vertebrae together. When Is Fusion Needed? Fusing the vertebrae may be considered for several reasons. These include: treatment of a fractured (broken) vertebra; correction of deformity (spinal curves or slippages); elimination of pain from painful motion; treatment of instability; and treatment of some cervical disc herniations.
    [Show full text]
  • Kyphoplasty/Vertebroplasty, Thoracic Spine
    Musculoskeletal Surgical Services: Spine Fusion/Stabilization Surgery; Kyphoplasty/Vertebroplasty, Thoracic Spine POLICY INITIATED: 06/30/2019 MOST RECENT REVIEW: 06/30/2019 POLICY # HH-5641 Overview Statement The purpose of these clinical guidelines is to assist healthcare professionals in selecting the medical service that may be appropriate and supported by evidence to improve patient outcomes. These clinical guidelines neither preempt clinical judgment of trained professionals nor advise anyone on how to practice medicine. The healthcare professionals are responsible for all clinical decisions based on their assessment. These clinical guidelines do not provide authorization, certification, explanation of benefits, or guarantee of payment, nor do they substitute for, or constitute, medical advice. Federal and State law, as well as member benefit contract language, including definitions and specific contract provisions/exclusions, take precedence over clinical guidelines and must be considered first when determining eligibility for coverage. All final determinations on coverage and payment are the responsibility of the health plan. Nothing contained within this document can be interpreted to mean otherwise. Medical information is constantly evolving, and HealthHelp reserves the right to review and update these clinical guidelines periodically. No part of this publication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, or otherwise, without permission
    [Show full text]
  • Spinal Instrumentation Rescue with Cement Augmentation
    Published September 13, 2018 as 10.3174/ajnr.A5795 ORIGINAL RESEARCH SPINE Spinal Instrumentation Rescue with Cement Augmentation X A. Cianfoni, X M. Giamundo, X M. Pileggi, X K. Huscher, X M. Shapiro, X M. Isalberti, X D. Kuhlen, and X P. Scarone ABSTRACT BACKGROUND AND PURPOSE: Altered biomechanics or bone fragility or both contribute to spine instrumentation failure. Although revision surgery is frequently required, minimally invasive alternatives may be feasible. We report the largest to-date series of percuta- neous fluoroscopically guided vertebral cement augmentation procedures to address feasibility, safety, results and a variety of spinal instrumentation failure conditions. MATERIALS AND METHODS: A consecutive series of 31 fluoroscopically guided vertebral augmentation procedures in 29 patients were performed to address screw loosening (42 screws), cage subsidence (7 cages), and fracture within (12 cases) or adjacent to (11 cases) the instru- mented segment. Instrumentation failure was deemed clinically relevant when resulting in pain or jeopardizing spinal biomechanical stability. The main study end point was the rate of revision surgery avoidance; feasibility and safety were assessed by prospective recording of periprocedural technical and clinical complications; and clinical effect was measured at 1 month with the Patient Global Impression of Change score. RESULTS: All except 1 procedure was technically feasible. No periprocedural complications occurred. Clinical and radiologic follow-up was available in 28 patients (median, 16 months) and 30 procedures. Revision surgery was avoided in 23/28 (82%) patients, and a global clinical benefit (Patient Global Impression of Change, 5–7) was reported in 26/30 (87%) cases at 1-month follow-up, while no substantial change (Patient Global Impression of Change, 4) was reported in 3/30 (10%), and worsening status (Patient Global Impression of Change, 3), in 1/30 (3%).
    [Show full text]
  • Spinal Fusion Surgery Guide
    Spinal Fusion Surgery Guide TABLE OF CONTENTS Page 3: The Spine Page 4: Spine Surgery Page 7: Before Surgery Page 9: Pre-operative Medications Page 10: Day of Surgery Page 11: After Surgery Page 13: Post-Operative Instructions Page 16: Home After Surgery Page 17: Post-operative Medications Page 18: Glossary 2 THE SPINE Your spine is made of 26 bones known as vertebrae (7 cervical, 12 thoracic, 5 lumbar, the sacrum and coccyx). Each vertebra is separated by a disc (except the top two neck vertebrae). Each disc has a soft, jelly-like center surrounded by a tough outer layer of fibers known as the annulus. Discs, bony structures, ligaments and strong muscles stabilize the spine. The spinal cord, which is the nerve center of the body, connects the brain to the rest of the body, and passes through the bony spine and usually ends at approximately L1 or L2. Beyond that, nerve roots are present in a fluid-filled tube. The outer layer of this tube is called the dura. At each segment, nerve roots exit/enter the spinal canal on each side (left and right). Nerve roots come from the spinal cord and carry electrical impulses to and from muscles, organs and other structures. Compression or squeezing on the nerves in the spinal cord or nerve roots may be causing many of the different types of symptoms that you may be experiencing. These symptoms may include back pain, leg pain, weakness in the legs, numbness in the legs. Other more serious symptoms include problems with bowel or bladder function.
    [Show full text]
  • Anterior Cervical Fusion Surgery a Guide for Patients and Their Caregivers Contents
    Anterior Cervical Fusion Surgery A guide for patients and their caregivers Contents About the Spine . .1 . About This Surgery . 5. Getting Ready for Surgery . .10 . At the Hospital . 16 After the Hospital: Your Recovery . 22 Six Weeks after Surgery: What to Expect . .28 . Common Questions . .29 . www.VanderbiltHealth.com 615.322.5000 For information only. Not to replace the advice of your health care provider. Copyright © 2016 Vanderbilt University Medical Center. All rights reserved. HC1693 (01/2019) About the Spine The spine is a stack of bones that runs down the The spine has 26 bones middle of your back. It starts at the bottom of • There are 24 bones (vertebrae) that start at the your skull and goes all the way down to the end top of your spine. These are the separate bones your tailbone. The spine: that connect like puzzle pieces. There are: • supports your body – 7 vertebrae in the neck area (cervical) • allows you to move freely – 12 vertebrae in the chest area (thoracic) • houses and protects the spinal cord—the – 5 vertebrae in the lower back (lumbar) nerve center of your body. • The next to the last bone of your spine is the sacrum. The sacrum is actually 1 large bone View of the spine from the front made of 5 fused bones. • The bone at the very end of the spine is the 7 cervical vertebrae tailbone (the coccyx). 12 thoracic vertebrae 5 lumbar vertebrae sacrum coccyx - 1 - There are discs between most of the bones Details about the discs in the spine • Each disc has a spongy center (nucleus) and There are soft pads of tissue between most of a tougher outer ring (annulus).
    [Show full text]