LETTERS TO THE EDITOR
IMPROVING REFERRING PHYSICIANS’ UNDERSTANDING OF ELECTROMYOGRAPHY REPORTS I read with interest the study by Mauricio et al. regarding electromyography reports.1 The authors highlighted 3 important concepts for improving referring physicians’ understanding of electromyography reports: (1) referring physicians should be aware that normal electromyography/nerve conduction studies (EMG/NCS) would not exclude an ongoing process producing root demyelination or irritation without axonal loss; (2) the diagnosis and treatment of radiculopathy does not rest solely upon the EMG/NCS findings; and (3) the EMG temporal profile may not correlate with the timing of the patient’s symptoms. Many referrals to electrodiagnostic laboratories are for non-myelopathic traumatic injuries to the spine region that cause axial referred vs. radicular signs and symptoms. The history, examination, and imaging studies are essential elements for the diagnostic and treatment algorithm. Electrodiagnostic evidence of lumbar radiculopathy in symptomatic patients, combined with radicular pain and physical findings consistent with lumbosacral radiculopathy can be an independent predictor of long-term improvement in pain after intralaminar lumbar epidural steroid injection (ESI). Improvements in abnormal EMG/ NCS studies can be significant. However, patients with normal EMG/NCS studies also tend to respond favorably to lumbar ESI.2 Therefore, EMG/NCS cannot be used to justify or deny ESI therapy. Also, results of EMG/NCS studies cannot predict surgical outcome.3 EMG/NCS study can localize a lesion to a particular root; however, the pathophysiology of the lesion cannot be identified, and the specific anatomical level for laminectomy, foraminotomy, or ESI may not correspond to the root segment, such as with lateral vs. posterolateral disk herniation.4 EMG/NCS studies are an extension of the neurological clinical evaluation. Because they focus on the peripheral nervous system, one must recognize that lesions do not occur in electrodiagnostic isolation but are to be taken in conjunction with a thorough neurological examination and imaging studies to assess the patient’s clinical picture. EMG/NCS studies often have low combined sensitivity and specificity for confirmation of root injury and high combined sensitivity and specificity for distal neuropathic lesions, such as neu772
Letters to the Editor
ropathy, mononeuropathy, or plexopathy. The referring physician should recognize that the most important indication for EMG/NCS studies in the evaluation of patients with spinal trauma with radicular symptoms is to assist in distinguishing between root and distal neuropathic or myopathic lesions that cannot be resolved by history, physical examination, and imaging studies.4 James A. Charles, MD, FAAN Department of Neurosciences, New Jersey Medical School, Newark, New Jersey, USA 1. Mauricio EA, Dimber EL, Kennely KD, Rubin DI. Improving referring physicians’ understanding of electromyography reports when qualifying radiculopathies: a need for standard terminology. Muscle Nerve 2014;49:129–130. 2. Annaswamy TM, Bierner SM, Chouteau W, Elliott AC. Needle electromyography predicts outcome after lumbar epidural steroid injection. Muscle Nerve 2012;45:346–355. 3. Spengler DM, Ouellette EA, Battie M, Zeh J. Elective discectomy for herniation of a lumbar disc: additional experience with objective method. J Bone Joint Surg Am 1990;72:230–237. 4. Charles JA, Souayah N. EMG/NCS in the evaluation of spine trauma with radicular symptoms. Neurol Clin Pract 2013;3:8–14.
Published online 11 February 2014 in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/mus.24203
--------------------------------------------------------REPLY
We thank Dr. Charles for his comments. He has highlighted the important point that, while an electromyogram (EMG) is an extension of the neurologic examination, certain limitations must be recognized. An EMG must be interpreted in the context of the patient’s clinical symptoms, examination findings, and imaging studies. While the focus of our study was on the referring physicians’ understanding of the specific nomenclature used to describe radiculopathies, we realize that there may also be confusion surrounding the diagnostic value of the EMG findings.1 We agree that electrophysiologic studies should not be used in isolation in the evaluation and treatment of patients. In fact, prior studies of the sensitivity and specificity of EMG studies in lumbosacral MUSCLE & NERVE
May 2014
IMPROVING REFERRING PHYSICIANS’ UNDERSTANDING OF ELECTROMYOGRAPHY REPORTS I read with interest the study by Mauricio et al. regarding electromyography reports.1 The authors highlighted 3 important concepts for improving referring physicians’ understanding of electromyography reports: (1) referring physicians should be aware that normal electromyography/nerve conduction studies (EMG/NCS) would not exclude an ongoing process producing root demyelination or irritation without axonal loss; (2) the diagnosis and treatment of radiculopathy does not rest solely upon the EMG/NCS findings; and (3) the EMG temporal profile may not correlate with the timing of the patient’s symptoms. Many referrals to electrodiagnostic laboratories are for non-myelopathic traumatic injuries to the spine region that cause axial referred vs. radicular signs and symptoms. The history, examination, and imaging studies are essential elements for the diagnostic and treatment algorithm. Electrodiagnostic evidence of lumbar radiculopathy in symptomatic patients, combined with radicular pain and physical findings consistent with lumbosacral radiculopathy can be an independent predictor of long-term improvement in pain after intralaminar lumbar epidural steroid injection (ESI). Improvements in abnormal EMG/ NCS studies can be significant. However, patients with normal EMG/NCS studies also tend to respond favorably to lumbar ESI.2 Therefore, EMG/NCS cannot be used to justify or deny ESI therapy. Also, results of EMG/NCS studies cannot predict surgical outcome.3 EMG/NCS study can localize a lesion to a particular root; however, the pathophysiology of the lesion cannot be identified, and the specific anatomical level for laminectomy, foraminotomy, or ESI may not correspond to the root segment, such as with lateral vs. posterolateral disk herniation.4 EMG/NCS studies are an extension of the neurological clinical evaluation. Because they focus on the peripheral nervous system, one must recognize that lesions do not occur in electrodiagnostic isolation but are to be taken in conjunction with a thorough neurological examination and imaging studies to assess the patient’s clinical picture. EMG/NCS studies often have low combined sensitivity and specificity for confirmation of root injury and high combined sensitivity and specificity for distal neuropathic lesions, such as neu772
Letters to the Editor
ropathy, mononeuropathy, or plexopathy. The referring physician should recognize that the most important indication for EMG/NCS studies in the evaluation of patients with spinal trauma with radicular symptoms is to assist in distinguishing between root and distal neuropathic or myopathic lesions that cannot be resolved by history, physical examination, and imaging studies.4 James A. Charles, MD, FAAN Department of Neurosciences, New Jersey Medical School, Newark, New Jersey, USA 1. Mauricio EA, Dimber EL, Kennely KD, Rubin DI. Improving referring physicians’ understanding of electromyography reports when qualifying radiculopathies: a need for standard terminology. Muscle Nerve 2014;49:129–130. 2. Annaswamy TM, Bierner SM, Chouteau W, Elliott AC. Needle electromyography predicts outcome after lumbar epidural steroid injection. Muscle Nerve 2012;45:346–355. 3. Spengler DM, Ouellette EA, Battie M, Zeh J. Elective discectomy for herniation of a lumbar disc: additional experience with objective method. J Bone Joint Surg Am 1990;72:230–237. 4. Charles JA, Souayah N. EMG/NCS in the evaluation of spine trauma with radicular symptoms. Neurol Clin Pract 2013;3:8–14.
Published online 11 February 2014 in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/mus.24203
--------------------------------------------------------REPLY
We thank Dr. Charles for his comments. He has highlighted the important point that, while an electromyogram (EMG) is an extension of the neurologic examination, certain limitations must be recognized. An EMG must be interpreted in the context of the patient’s clinical symptoms, examination findings, and imaging studies. While the focus of our study was on the referring physicians’ understanding of the specific nomenclature used to describe radiculopathies, we realize that there may also be confusion surrounding the diagnostic value of the EMG findings.1 We agree that electrophysiologic studies should not be used in isolation in the evaluation and treatment of patients. In fact, prior studies of the sensitivity and specificity of EMG studies in lumbosacral MUSCLE & NERVE
May 2014
