The clinical update on the utility of the clinical examination for carpal tunnel syndrome1 is a review of a review. The original article highlights the pitfalls of using MEDLINE-based reviews to generate clinical practice guidelines.2 The basic assumption of Kathryn Myers' clinical update is that electrodiagnostic studies represent the gold standard for diagnosis, an assumption the authors of the original article themselves admit is flawed.
Myers extracts the recommendation that “decreased pain sensation in the median nerve distribution is the most helpful finding in making the diagnosis.” This finding will only help to diagnose advanced carpal tunnel syndrome, in which the patient's sensation at rest is impaired. Use of this finding will indeed increase the specificity of the examiner's results but will seriously decrease the sensitivity of the clinical examination. If practitioners follow this guideline they will grossly underdiagnose carpal tunnel syndrome and will exclude many patients who would benefit from treatment.
Recent studies point to the carpal compression test as the most reliable and valid physical examination test for the diagnosis of carpal tunnel syndrome.3,4,5 The goal in recommending a clinical examination technique for the diagnosis of a disorder is both high specificity and sensitivity, and the carpal compression test is a markedly better way to achieve this goal than assessment of median nerve pain threshold.
Signature
Timothy J. Best
Hand and plastic surgeon Sault Ste. Marie, Ont.
References
- 1.Myers KA. Utility of the clinical examination for carpal tunnel syndrome. CMAJ 2000;163(5):605. [PMC free article] [PubMed]
- 2.D'Arcy CA, McGee S. Does this patient have carpal tunnel syndrome? JAMA 2000;283:3110-7. [DOI] [PubMed]
- 3.Marx RG, Bombardier C, Wright JG. What do we know about the reliability and validity of physical examination tests used to examine the upper extremity? J Hand Surg 1999;24A:185-93. [DOI] [PubMed]
- 4.Marx RG, Hedak PL, Bombardier C, Graham B, Goldsmith C, Wright JG. The reliability of physical examination for carpal tunnel syndrome. J Hand Surg 1998;23B:499-502. [DOI] [PubMed]
- 5.Mackinnon SE, Dellon AL. Surgery of the peripheral nerve. New York: Thieme Medical Publishers; 1988.