The Diagnostic Value of Ultrasonography in Korean Carpal Tunnel Syndrome Patients

Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy. In most cases of CTS, characteristic clinical findings alone may be sufficient for diagnosis. Although the electrodiagnostic tests (EDT) have been reported to be high sensitivity and specificity, other studies noted a substantial false-positive and false-negative rate of 1020%. Since 1992, Buchberger et al. has been the first to quantify changes in CTS using ultrasonography (USG), many studies demonstrated a consistent and significantly increased median nerve cross-sectional area (CSA) in patients with CTS. The most frequently used criterion for USG study is at the level of carpal tunnel inlet, where the median nerve is identified most easily. However, the normal range and pathologic threshold of median nerve CSA vary widely between laboratories. The pathologic thresholds are ranging from 9 to 14 mm. The object of our study is to establish the clinical efficacy of USG in patients with CTS through reestablish the normal range and pathologic threshold of median nerve CSA at the level of carpal tunnel inlet in prospectively recruited patients with and without CTS; and also to correlate ultrasonographic measurements with electrophysiological measurements of CTS severity.