Diagnostic accuracy of ultrasonography vs. electromyography in carpal tunnel syndrome: a systematic review of literature.

A plethora of research investigates sonography vs. electrodiagnostic testing (EDX) for diagnosis of carpal tunnel syndrome (CTS). Through database searches, hand searches and communication with authors, 582 abstracts published from 1999 to 2009 were identified. A comprehensive systematic review process resulted in inclusion of 23 studies. Significant methodologic discrepancies among the studies limited the ability to complete a meta-analysis to identify specific diagnostic thresholds. Instead, the data were reviewed to provide implications for clinical utility of sonography as a screening tool as a compliment to EDX and to suggest continued and future research. The largest cross-sectional area of the median nerve within the carpal tunnel region has high potential for clinical screening, especially in individuals with severe CTS. Identifying swelling of the nerve through comparative measurements, qualitative analysis and Doppler techniques all require further investigation. Screening protocols may be enhanced through exploration of sonography in patients with mild CTS and false-negative EDX.