High resolution ultrasonography in the diagnosis of the carpal tunnel syndrome.

Purpose: Carpal tunnel syndrome (CTS) is a neuropathy caused by compression of the median nerve in the carpal tunnel. Our purpose was to evaluate the role of high-resolution ultrasonography (US), performed with a 10-13 MHz probe, in the detection of morphovolumetric changes of the median nerve to confirm the clinical diagnosis.
Materials and Methods: Fifty healthy volunteers were examined first by US; subsequently we studied 294 wrists in 186 symptomatic patients, calculating the cross-sectional area of the median nerve at three levels: before the median nerve enters the carpal tunnel, at the carpal tunnel inlet and at the outlet. US was considered diagnostic for CTS when the median nerve area increased at the inlet or flattening was present along the carpal tunnel.
Results: Ultrasonography showed pathologic findings in 267 wrists: in 261 cases morphovolumetric changes of the median nerve were found; in six cases anatomic variant of the median nerve was detected. Surgery was performed in 277 cases and all patients became symptom-free. The sensitivity of US was 96.3 % .
Conclusions: Our study confirms that quantitative ultrasonographic assessment is a useful support in confirming the clinical diagnosis of CTS.