The sensitivity and specificity of ultrasound for the diagnosis of carpal tunnel syndrome: a meta-analysis.

BACKGROUND: Carpal tunnel syndrome (CTS) is the most commonly diagnosed compression neuropathy of the upper extremity. Current AAOS recommendations are to obtain a confirmatory electrodiagnostic test in patients for whom surgery is being considered. Ultrasound has emerged as an alternative confirmatory test for CTS; however, its potential role is limited by lack of adequate data for sensitivity and specificity relative to electrodiagnostic testing. QUESTIONS/PURPOSES: In this meta-analysis we determined the sensitivity and specificity of ultrasound in the diagnosis of CTS.
METHODS: A PubMed/MEDLINE search identified 323 articles for review. After applying exclusion criteria, 19 articles with a total sample size of 3131 wrists were included for meta-analysis. Three groups were created: a composite of all studies, studies using clinical diagnosis as the reference standard, and studies using electrodiagnostic testing as the reference standard.
RESULTS: The composite sensitivity and specificity of ultrasound for the diagnosis of CTS, using all studies, were 77.6% (95% CI 71.6-83.6%) and 86.8% (95% CI 78.9-94.8%), respectively.
CONCLUSIONS: The wide variations of sensitivities and specificities reported in the literature have prevented meaningful analysis of ultrasound as either a screening or confirmatory tool in the diagnosis of CTS. The sensitivity and specificity of ultrasound in the diagnosis of CTS are 77.6% and 86.8%, respectively. Although ultrasound may not replace electrodiagnostic testing as the most sensitive and specific test for the diagnosis of CTS given the values reported in this meta-analysis, it may be a feasible alternative to electrodiagnostic testing as the first-line confirmatory test. LEVEL OF EVIDENCE: Level III, systematic review of Level III studies. See Guidelines for Authors for a complete description of levels of evidence.