Assessment of Traumatic Nerve Injuries

American Association of Neuromuscular & Electrodiagnostic Medicine AANEM ASSESSMENT OF TRAUMATIC NERVE INJURIES Lawrence R. Robinson, MD Jeffrey G. Jarvik, MD, MPH David G. Kline, MD 2005 AANEM COURSE G AANEM 52nd Annual Scientific Meeting Monterey, California Assessment of Traumatic Nerve Injuries Lawrence R. Robinson, MD Jeffrey G. Jarvik, MD, MPH David G. Kline, MD 2005 COURSE G AANEM 52nd Annual Scientific Meeting Monterey, California AANEM Copyright © September 2005 American Association of Neuromuscular & Electrodiagnostic Medicine 421 First Avenue SW, Suite 300 East Rochester, MN 55902 PRINTED BY JOHNSON PRINTING COMPANY, INC. ii Assessment of Traumatic Nerve Injuries Faculty Lawrence R. Robinson, MD David G. Kline, MD Professor Boyd Professor and Head Department of Rehabilitation Medicine Department of Neurosurgery University of Washington Louisiana State University Medical Center Seattle, Washington New Orleans, Louisiana Dr. Robinson attended Baylor College of Medicine and completed his res- Dr. Kline is currently a Boyd Professor and Head of the Department of idency training in rehabilitation medicine at the Rehabilitation Institute of Neurosurgery at Louisiana State University (LSU) Medical Center in New Chicago. He now serves as professor and chair of the Department of Orleans. He earned his medical degree from the University of Rehabilitation Medicine at the University of Washington and is the Pennsylvania, then performed his internship at the University of Michigan. Director of the Harborview Medical Center Electrodiagnostic Laboratory. He performed residencies at the University of Michigan and Walter Reed He is also currently Vice Dean for Clinical Affairs at the University of General Hospital and Institute of Research. Dr. Kline has served on sever- Washington. His current clinical interests include the statistical interpreta- al editorial boards including Neurosurgery, Microsurgery, and the Journal tion of electrophysiologic data, laryngeal electromyography, and the study of Reconstructive Microsurgery, among others. He is also active in many of traumatic neuropathies. He recently received the Distinguished medical societies. Dr. Kline was recently named a Boyd Professor at LSU, Academician Award from the Association of Academic Physiatrists and this which is only given to faculty members who have attained national or year is receiving the AANEM Distinguished Researcher Award. international distinction for outstanding teaching, research, or other cre- ative achievement. Jeffrey G. Jarvik, MD, MPH Professor Department of Radiology and Neurology Adjunct Professor Faculty had nothing to disclose. Department of Health Services University of Washington Seattle, Washington As Director of Neuroradiology at the University of Washington, Dr. Jarvik’s clinical work encompasses the entire range of neuroradiology. His clinical and research focus has been on spinal and peripheral nerve imaging. His academic focus has been on health services as it relates to diagnostic imaging, e.g., how diagnostic imaging influences therapeutic decision making and patient outcomes. Dr. Jarvik is a member of the American Society of Neuroradiology, the American College of Radiology, and the Radiological Society of North America, among others. Please be aware that some of the medical devices or pharmaceuticals discussed in this handout may not be cleared by the FDA or cleared by the FDA for the specific use described by the authors and are “off-label” (i.e., a use not described on the product’s label). “Off-label” devices or pharmaceuticals may be used if, in the judgement of the treating physician, such use is medically indicated to treat a patient’s condition. Information regarding the FDA clearance status of a particular device or pharmaceutical may be obtained by reading the product’s package labeling, by contacting a sales representative or legal counsel of the manufacturer of the device or pharmaceutical, or by contacting the FDA at 1-800-638-2041. Course Chair: Alan R. Berger, MD The ideas and opinions expressed in this publication are solely those of the specific authors and do not necessarily represent those of the AANEM. iii Assessment of Traumatic Nerve Injuries Contents Faculty ii Objectives iii Course Committee iv Traumatic Nerve Injury to Peripheral Nerves 1 Lawrence R. Robinson, MD Peripheral Nerve Magnetic Resonance Imaging: The Median Nerve in Carpal Tunnel Syndrome 11 Jeffrey G. Jarvik, MD, MPH Surgical Management of Nerve Injuries 19 David G. Kline, MD CME Self-Assessment Test 29 Evaluation 31 Member Benefit Recommendations 33 Future Meeting Recommendations 35 O BJECTIVES—This course will provide an overview of the evaluation and management of traumatic nerve injuries. After attending this course, the participant will (1) understand the importance and time frame for the electrodiagnosis of nerve trauma, (2) learn the “state- of-the-art” concepts and future potential of neuroimaging of peripheral nerve injuries, and (3) learn the most important principles of the clinical and surgical management of peripheral nerve injuries. P REREQUISITE—This course is designed as an educational opportunity for residents, fellows, and practicing clinical EDX physicians at an early point in their career, or for more senior EDX practitioners who are seeking a pragmatic review of basic clinical and EDX principles. It is open only to persons with an MD, DO, DVM, DDS, or foreign equivalent degree. A CCREDITATION S TATEMENT—The AANEM is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education (CME) for physicians. CME CREDIT—The AANEM designates attendance at this course for a maximum of 3.25 hours in category 1 credit towards the AMA Physician’s Recognition Award. This educational event is approved as an Accredited Group Learning Activity under Section 1 of the Framework of Continuing Professional Development (CPD) options for the Maintenance of Certification Program of the Royal College of Physicians and Surgeons of Canada. Each physician should claim only those hours of credit he/she actually spent in the activity. The American Medical Association has determined that non-US licensed physicians who participate in this CME activity are eligible for AMA PMR category 1 credit. CME for this course is available 9/05 - 9/08. iv 2004-2005 AANEM COURSE COMMITTEE Kathleen D. Kennelly, MD, PhD Jacksonville, Florida Thomas Hyatt Brannagan, III, MD Dale J. Lange, MD Jeremy M. Shefner, MD, PhD New York, New York New York, New York Syracuse, New York Timothy J. Doherty, MD, PhD, FRCPC Subhadra Nori, MD T. Darrell Thomas, MD London, Ontario, Canada Bronx, New York Knoxville, Tennessee Kimberly S. Kenton, MD Bryan Tsao, MD Maywood, Illinois Shaker Heights, Ohio 2004-2005 AANEM PRESIDENT Gary Goldberg, MD Pittsburgh, Pennsylvania Traumatic Injury to Peripheral Nerves Lawrence R. Robinson, MD Professor and Chair Department of Rehabilitation Medicine University of Washington Seattle, Washington EPIDEMIOLOGY OF PERIPHERAL NERVE TRAUMA 60% have a traumatic brain injury.30 Conversely, of those with traumatic brain injury admitted to rehabilitation units, Traumatic injury to peripheral nerves results in considerable 10-34% have associated peripheral nerve injuries.7,14,39 It is disability everywhere in the world. In peacetime, peripheral often easy to miss peripheral nerve injuries in the setting of nerve injuries commonly result from trauma due to motor CNS trauma. Since the neurologic history and examination vehicle accidents, and less commonly from penetrating trau- is limited, early hints to a superimposed peripheral nerve ma, falls, and industrial accidents. Out of all patients admit- lesion might be only flaccidity, areflexia, and reduced move- ted to Level I trauma centers, it is estimated that roughly 2- ment of a limb. 3% have peripheral nerve injuries.30,36 If plexus and root injuries are also included, the incidence is about 5%.30 Peripheral nerve injuries are of significant import as they impede recovery of function and return to work, and carry In the upper limb, the most commonly reported nerve risk of secondary disabilities from falls, fractures, or other sec- injured is the radial nerve, followed by the ulnar and median ondary injuries. An understanding of the classification, nerves.30,36 Lower limb peripheral nerve injuries are less com- pathophysiology, and electrodiagnosis of these lesions is crit- mon, with the sciatic nerve most frequently injured, followed ical to the appropriate diagnosis, localization, and manage- by the peroneal and rarely tibial or femoral nerves. Fractures ment of peripheral nerve trauma. of nearby bones are commonly associated, such as humeral fractures with radial neuropathy. CLASSIFICATION OF NERVE INJURIES In wartime, peripheral nerve trauma is much more common and most of physician’s knowledge about peripheral nerve There are two predominant schemes that have been proposed injury, repair, and recovery comes from experience derived in for classification of peripheral nerve traumatic injuries; that World Wars I and II, and subsequent wars.20,35,40 of Seddon35 and that of Sunderland40 (Table 1). The former is more commonly used in the literature. Seddon has used the Peripheral nerve injuries may be seen as an isolated nervous terms “neurapraxia,” “axonotmesis,” and “neurotmesis” to system injury, but may also accompany central nervous sys- describe peripheral nerve injuries.35 Neurapraxia is a compar- tem (CNS) trauma, not only compounding the disability,

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