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Nerve Conduction Studies for Carpal Tunnel Syndrome: Gold Standard or Unnecessary Evil?

2017; Slack Incorporated (United States); Volume: 40; Issue: 4 Linguagem: Inglês

10.3928/01477447-20170627-01

1938-2367

Jeremy D.P. Bland,

Nerve Injury and Rehabilitation

Letter to the EditorNerve Conduction Studies for Carpal Tunnel Syndrome: Gold Standard or Unnecessary Evil? Jeremy D. P. Bland, MB ChB, , MB ChB Jeremy D. P. Bland, MB ChB Orthopedics, 2017;40(4):198Published Online:June 27, 2017https://doi.org/10.3928/01477447-20170627-01Cited by:8PDFView Full Text ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinkedInRedditEmail SectionsMore"Nerve Conduction Studies for Carpal Tunnel Syndrome: Gold Standard or Unnecessary Evil?." Orthopedics, 40(4), p. 1981.Fowler JR. Nerve conduction studies for carpal tunnel syndrome: gold standard or unnecessary evil?Orthopedics. 2017; 40(3):141–142. doi:.10.3928/01477447-20170419-01 LinkGoogle Scholar2.Graham B. The value added by electrodiagnostic testing in the diagnosis of carpal tunnel syndrome. J Bone Joint Surg Am. 2008; 90(12):2587–2593.10.2106/JBJS.G.01362 Crossref MedlineGoogle Scholar3.Tan JS, Tan AB. Outcomes of open carpal tunnel releases and its predictors: a prospective study. Hand Surg. 2012; 17(3):341–345.10.1142/S0218810412500281 Crossref MedlineGoogle Scholar4.Straub TA. Endoscopic carpal tunnel release: a prospective analysis of factors associated with unsatisfactory results. Arthroscopy. 1999; 15(3):269–274.10.1016/S0749-8063(99)70033-2 Crossref MedlineGoogle Scholar5.Bland JDP. Do nerve conduction studies predict the outcome of carpal tunnel decompression?Muscle Nerve. 2001; 24(7):935–940.10.1002/mus.1091 Crossref MedlineGoogle Scholar6.Padua L, Padua R, Aprile I, Pasqualetti P, Tonali Pfor Italian CTS Study Group. Multiperspective follow-up of untreated carpal tunnel syndrome: a multicenter study. Neurology. 2001; 56(11):1459–1466.10.1212/WNL.56.11.1459 Crossref MedlineGoogle Scholar ORTHO Orthopedics Orthopedics 0147-74471938-2367 SLACK Incorporated Thorofare, NJ 10.3928/01477447-20170627-01 10.3928_01477447-20170627-01 Letter to the Editor Reply: Fowler John R. , , MD Pittsburgh, Pennsylvania The author has no relevant financial relationships to disclose. 01 07 2017 40 4 198 199 Copyright 2017, SLACK Incorporated 2017 SLACK Incorporated I thank Dr Bland for his comments. I whole-heartedly agree that it is incumbent on all of us, not just those who practice electrophysiology, to demonstrate that our tests and treatments make a positive impact on the care of our patients. I again assert that, for most patients with carpal tunnel syndrome (CTS), the addition of nerve conduction studies (NCSs) does not add significant information and therefore does not make a positive impact on patient care. I clearly stated in the guest editorial 1 that the "routine" use of NCSs is not supported by the literature. I agree (and stated in the guest editorial) that there are times when the diagnosis is not clear and when NCSs may find an unexpected diagnosis. However, I think that those cases are relatively rare, and I would be interested to see a "number needed to treat" for how many patients with "classic" CTS must be tested to find an unexpected diagnosis that positively affects patient care. The flip side to that is how many patients will we treat, with either splint, injection, therapy, or surgery, who did not truly have CTS but rather had asymptomatic slowing of the median nerve across the wrist? I know that Dr Bland has performed a truly impressive amount of research regarding the electrodiagnostic evaluation of CTS. I encourage him to query his Canterbury database to try to calculate the number needed to treat. According to Dr Bland, "Nerve conduction studies do not absolutely define the presence of CTS." I would argue that many proponents of NCSs and also many physicians and surgeons incorrectly assume that NCSs do define the presence of CTS. My impression is that the average physician or surgeon in practice just looks at the NCS report and if it shows slowing of the median nerve across the wrist, considers it diagnostic for CTS. Dr Bland's depth of knowledge and experience allows him to "see the whole picture." I especially appreciate his stating, "Using the results rationally requires a detailed understanding of the relationship among NCS results, examination findings, and treatment outcomes." I do not feel that I was arguing over the rate of false-positive and false-negative results but rather just pointing out that, in certain clinical scenarios, NCSs may not be as "accurate" as some might think. In addition, I was not at all implying that clinical diagnosis is correct 100% of the time but merely that the addition of NCSs did not appear to change the outcome of carpal tunnel release. 2 The cut-off values used for a positive diagnosis of CTS on NCSs can vary greatly between laboratories, and there is no universal standard. In a recent review, Chen et al 3 noted that of the 1111 articles published on the distal motor latency of the median nerve, only 1 article met their criteria for high statistical and methodological standards and was performed with normal, healthy controls. This highlights the lack of high level of evidence studies despite a large volume of research. Chen et al found that a distal motor latency of 4.5 milliseconds for the medial nerve was the upper limit for normal, healthy controls. In my review of the literature, I have noted that nearly all studies use a cut-off value well below 4.5 milliseconds for a positive diagnosis of CTS. I concede that looking only at one cut-off value greatly reduces the diagnostic accuracy of NCSs and should not be used as the sole diagnostic criterion in clinical practice. However, the lack of standardization and that many laboratories use values well below this cut-off value are concerning. I would be careful concluding that patients can or should be indicated for surgery based on the results of NCSs. Although I agree that, anecdotally, patients with more severe disease, based on either history and physical examination or NCS, may be more likely to be offered surgery, my review of the literature has found little evidence that this strategy improves patient outcomes. I base my surgical indications mostly on a failure of nonoperative treatment. If patients do not experience symptomatic and clinical improvement with a course of splinting, activity modification, and/or injections and are not satisfied with continued nonoperative treatment, then they are offered surgery. Many patients who have mild disease, from both a clinical standpoint and a NCS standpoint, do not get better with nonoperative treatment, are offered surgery, and do well with carpal tunnel release. It is an honor to have a true expert in the field such as Dr Bland respond to my guest editorial and share his thoughts. I find it incredibly interesting that, despite literally thousands of articles having been published on the diagnosis, treatment, and prognosis of CTS, many questions remain unanswered. I hope that high-level research will be conducted that helps to answer some of these questions and improve patient care. John R. Fowler, MD Pittsburgh, Pennsylvania Next article FiguresReferencesRelatedDetailsCited by Goru P, Butaliu G, Verma G, Haque S, Mustafa A and Paul A (2022) Effectiveness of ultrasound-guided local steroid injection to the wrist for the treatment of carpal tunnel syndrome: Is it worth it?, Egyptian Rheumatology and Rehabilitation, 10.1186/s43166-022-00121-5, 49:1, Online publication date: 1-Dec-2022. Tsamis K, Kontogiannis P, Gourgiotis I, Ntabos S, Sarmas I and Manis G (2021) Automatic Electrodiagnosis of Carpal Tunnel Syndrome Using Machine Learning, Bioengineering, 10.3390/bioengineering8110181, 8:11, (181) Kincaid J (2019) Upper extremity neuropathies Clinical Neurophysiology: Diseases and Disorders, 10.1016/B978-0-444-64142-7.00049-7, (197-205), . Chesterton L, Blagojevic-Bucknall M, Burton C, Dziedzic K, Davenport G, Jowett S, Myers H, Oppong R, Rathod-Mistry T, van der Windt D, Hay E and Roddy E (2018) The clinical and cost-effectiveness of corticosteroid injection versus night splints for carpal tunnel syndrome (INSTINCTS trial): an open-label, parallel group, randomised controlled trial, The Lancet, 10.1016/S0140-6736(18)31572-1, 392:10156, (1423-1433), Online publication date: 1-Oct-2018. Kleggetveit I and Jørum E (2018) Diagnosis of carpal tunnel syndrome, Scandinavian Journal of Pain, 10.1515/sjpain-2018-0089, 18:3, (333-337), Online publication date: 26-Jul-2018., Online publication date: 1-Jul-2018. Babaei-Ghazani A and Roomizadeh P (2018) The Role of Electrodiagnostic Studies in Carpal Tunnel Syndrome: Beyond Confirmation of Diagnosis, Orthopedics, 41:2, (67-67), Online publication date: 1-Mar-2018. Sonoo M, Menkes D, Bland J and Burke D (2018) Nerve conduction studies and EMG in carpal tunnel syndrome: Do they add value?, Clinical Neurophysiology Practice, 10.1016/j.cnp.2018.02.005, 3, (78-88), . Jones C, Stephens J and Gatchel R (2018) Musculoskeletal Pain and Disability Disorders Handbook of Rehabilitation in Older Adults, 10.1007/978-3-030-03916-5_6, (125-143), . Request Permissions InformationCopyright 2017, SLACK IncorporatedPDF download The author has no relevant financial relationships to disclose.