Source: Neurocase  |  Posted 9 years ago

Sonographic measurement of the median nerve cross-sectional area of the wrist is a sensitive and specific indicator of the presence of carpal tunnel syndrome, according to a small study.

Prompted by suggestions that sonography may be a good alternative to electrophysiologic studies, investigators from Prince of Wales Hospital and The Chinese University of Hong Kong compared sonographic measurements of the wrists of 35 people with and 35 people without carpal tunnel syndrome. Their goal was to determine the usefulness of this technique and the best diagnostic criteria. Participants with and without carpal tunnel syndrome were matched for age and sex.

Drs S. M. Wong and J. F. Griffith and colleagues analysed eight separate sonographic criteria in each wrist and compared data from the two groups to establish optimal diagnostic criteria.

The investigators found that increased cross-sectional area of the median nerve proximal to the tunnel inlet, at the tunnel inlet, and at the tunnel outlet was the most predictive measure of carpal tunnel syndrome, with significant differences between patients and controls.

Using a receiver operating characteristic (ROC) curve, the investigators determined that a cut-off value greater than 0.098 cm