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February 23, 2000

Clinical Diagnosis of Carpal Tunnel Syndrome

Author Affiliations

Phil B.FontanarosaMD, Deputy EditorIndividualAuthorStephen J.LurieMD, PhD, Fishbein FellowIndividualAuthor

JAMA. 2000;283(8):1000-1003. doi:10.1001/jama.283.8.999

To the Editor: Dr Atroshi and colleagues1 reported on the population prevalence of carpal tunnel syndrome (CTS), but their methods and conclusions raise 3 questions.

First, this study addresses patients not hands. Surely there was not 100% concordance between symptoms, physical signs, and nerve conduction studies between the patient's hands. How did the authors analyze data for a patient with bilateral symptoms but unilateral physical findings or nerve conduction studies?

Second, physical findings are notoriously unreliable in the diagnosis of CTS, especially in less severe cases. "Clinically certain CTS" would be more accurately described as "clinically suspected CTS." Furthermore, CTS was defined as either symptoms plus signs, or symptoms plus positive nerve conduction studies. In light of the greater reliability and clinical accuracy of nerve conduction tests,2 it would seem prudent to define CTS as symptoms plus positive nerve conduction studies, with or without physical signs.

Third, caution should be used in interpreting the findings on occupational hand use. Because this is a cross-sectional study, cause and effect cannot be inferred between work and CTS, especially in light of the methods, which relied on self-reported hand use and did not account for vocational or recreational hand use. Even with these caveats, the occupational association with CTS was quite tenuous.

I also take issue with the suggestion in the Editorial by Drs Franzblau and Werner3 regarding alternative tools for the diagnosis of CTS. Magnetic resonance imaging (MRI) has both technical and economic limitations, and the limited data in symptomatic and asymptomatic patients do not support its routine use in the diagnosis of CTS. Similarly, their recommendation for measurement of carpal tunnel pressures lacks sufficient scientific foundation. It is quite likely that increased carpal tunnel pressure is the final common pathway in the development of CTS.4 However, any clinician who has experience in using Wick catheter measurements of intracompartmental pressure realizes that this test is fraught with technical difficulties and that obtaining reliable measurements is extremely difficult. It is unclear how the use of 2 additional, unproven methods would increase diagnostic accuracy.

Atroshi  IGummesson  CJohnsson  ROrnstein  ERanstam  JRosén  I Prevalence of carpal tunnel syndrome in a general population.  JAMA. 1999;282:153-158.Google Scholar
Jablecki  CKAndary  MTSo  YTWilkins  DEWilliams  FH Literature review of the usefulness of nerve conduction studies and electromyography for the evaluation of patients with carpal tunnel syndrome.  Muscle Nerve. 1993;16:1392-1414.Google Scholar
Franzblau  AWerner  RA What is carpal tunnel syndrome?  JAMA. 1999;282:186-187.Google Scholar
Werner  COElmqvist  DOhlin  P Pressure and nerve lesion in the carpal tunnel.  Acta Orthop Scand. 1983;54:312-316.Google Scholar