A recent article by Charles and Souayah1 concludes that electrodiagnostic testing for spinal disorders is of little value. As neurologists and physiatrist subspecialists in the field, we disagree. Much of the evidence presented is incorrect, incomplete, or outdated, leading to faulty conclusions. This short letter can only highlight a few problems. The authors claim that no practice guidelines are available when these are readily available from the American Association of Neuromuscular and Electrodiagnostic Medicine and others.2,3 The article cites early unmasked studies to claim that paraspinal EMG has such a high false-positive rate that it is useless. This contrasts with the modern literature. For example, a masked, double-controlled study using validated reproducible techniques and established norms found that abnormal paraspinal EMG was 100% specific, in great contrast to the low specificity of diagnostic imaging.4 In addition to positively diagnosing spinal nerve disorders, EMG has also been shown in various situations to detect diseases that mimic spinal disorders, localize pathology for surgical and injection treatments, establish the duration of symptoms, establish the severity of disease, and predict or validate outcomes from certain spinal treatments. The literature, in contrast to this article, shows that electrodiagnosis is a useful and validated test for spinal disorders. A more detailed response can be found at www.aanem.org/defending-edx.
Disclosures
A. Haig has received funding for travel and speaker honoraria from academic organizations and universities; serves/has served on the editorial boards of PM&R, The Spine Journal, Journal of Back and Musculoskeletal Rehabilitation, Journal of Rehabilitation Medicine, and Portuguese Journal of Rehabilitation; is President of Haig et al consultants and has served as a consultant for Center for Health Care Research and Transformation, Jerudong Park Medical Centre, Brunei, and on occasional legal cases; performs electrodiagnostic clinical services and research at the University of Michigan; and has received funding from the NIH and the Center for Health Care Research and Transformation. T. Dillingham has received funding from the NIH. J. Kincaid performs EMG (50% effort) as chief of the EMG laboratories at Indiana University and Indiana University Health. P. Grant reports no disclosures.
- © 2013 American Academy of Neurology
Author Responds:
Our article1 did not conclude that electrodiagnostic testing for spinal disorders is of little value. We concluded that in a subset of patients with spinal trauma with radicular symptoms (STRS), there is limited evidence to support the use of EMG/nerve conduction studies (NCS). The American Association of Electrodiagnostic Medicine practice parameter for needle electromyographic evaluation of patients with suspected cervical radiculopathy was not a practice parameter offering guidelines for STRS.2 However, the article indicates that the sensitivity of needle EMG was 50% to 71%, an issue we discussed in our article.
Cho et al.3 found that none of the reviewed studies addressed the utility of electrodiagnostic testing in prognosticating outcome or response to treatments. Again, there was no discussion of a subset of patients with STRS.
The masked, double-controlled study using validated reproducible techniques and established norms did indeed find that abnormal paraspinal EMG was 100% specific. This study also found that abnormal paraspinal EMG was 30% sensitive.4 We agree that EMG has also been shown in various situations to detect diseases that mimic spinal disorders. This is why we concluded that EMG/NCS in STRS are indicated when there is a differential diagnosis between a root lesion and a distal neuropathic/myopathic lesion.1
The reaction of Haig et al. to our review has led them to underquote the points of our article, thereby disingenuously recreating our review of the literature into conclusions that we did not make. Good medical practice in patients with spinal trauma with radicular symptoms begins with the history, physical examination, and appropriate imaging study. As neurologists and clinical neurophysiologists, we see countless requests for EMG/NCS in these cases. Our review of the literature focused only on the clinical subject of STRS. We concluded only in this subset of patients that EMG/NCS is indicated and appropriate when there is a differential diagnosis of a root vs a distal neuropathic lesion that cannot be resolved by history, physical examination, and imaging. In the other patients with STRS, after completing the clinical evaluation and integrated imaging, any additional information from EMG/NCS, including paraspinal mapping, will have limited practical clinical usefulness in diagnosis, treatment decision, and prognosis. Our review is relevant and timely to address the epidemic of electrodiagnostic fraud in a scholarly manner5 and to address uncomfortable and costly unnecessary electrodiagnostic studies. There are cases of STRS that are complex with so many comorbidities that clinical judgment may need bolstering by EMG/NCS. An honest clinician neurologist or physiatrist who is treating patients with STRS should not have fears that our conclusions will lower their income. Relevant studies discuss electrodiagnostic testing and methodology of nerve root function that complements information from history, examination, and imaging studies in patients with radiculopathy, and demonstrate variable sensitivities and specificities due to various timing, anatomical, and comorbidity reasons. However, there are no practice parameters or established guidelines on the clinical utility of EMG/NCS in the evaluation of STRS. Current practice can include a systematic referral to the electrodiagnostic laboratory seeking information about neurologic complaints from STRS, and for preoperative and postoperative diagnostic and prognostic evaluations. This review suggests that such referrals, without clinical or imaging correlates, can be of low yield, notwithstanding the expense and discomfort from testing. It appears that unless there is a clinical differential diagnosis including a peripheral neuropathic/myopathic lesion vs a root lesion that cannot be resolved with the history, neurologic examination, and imaging studies, there is limited evidence to support the use of EMG/NCS in the evaluation, treatment, and prognosis of patients with STRS. Most study sample sizes are small, nonrandomized, or inadequately powered to assess improved outcomes from EMG/NCS studies. Better evidence for utility of EMG/NCS in STRS is required in the form of randomized clinical trials or large-scale outcome studies.1
Disclosures
The author reports no disclosures.
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