THE SENSITIVITY AND SPECIFICITY OF ULTRASOUND FOR THE DIAGNOSIS OF CARPAL TUNNEL SYNDROME: A META-ANALYSIS

Fowler, J. R., Gaughan J. P., & Ilyas, A.M. (2011).  The sensitivity and specificity of ultrasound for the diagnosis of carpal tunnel syndrome: A meta-analysis.  Clinical Orthopedics and Related Research, 469(4), 1089-1094.

The Skinny –The authors sought out to determine the sensitivity and specificity of ultrasound therapy for the diagnosis of carpal tunnel syndrome using three scenarios. 1.) using all studies regardless of reference standard 2.) using all studies with electrodiagnostic as the reference standards and 3.)  using all studies with clinical diagnosis as the gold standard. 

In the Weeds – The authors found a total of 19 articles that were included in the review.   Remember, sensitivity indicates a true positive rate and specificity indicates a true-negative rate. 

They found the sensitivity and specificity of ultrasound was 77.6% (71.6%-83.6%) and 86.8% (78.9%-94.8%), respectively. 

They found the sensitivity and specificity of electrodiagnostic testing to be 80.2% (71.3-89.0) and 78.7% (66.4-91.1, respectively).

Bringing it Home– Ultrasound showed a higher specificity but electrodiagnostic had a slightly higher sensitivity.  Although ultrasound may not replace electrodiagnostic testing as the most sensitive tool for diagnosing carpal tunnel, it may be a feasible alternative to electrodiagnostic testing as a first line confirmatory test.

Overall a very nicely done study however it was not without its limitation.  There was a lack of heterogeneity among the studies reviewed.  Both, ultrasound and electrodiagnostic testing it very operator dependent. The upside of ultrasound is it can be performed very quickly, it is often less expensive, and off course it is essentially pain-free. 

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