Does Ultrasonography Contribute Significantly to the Diagnosis of Carpal Tunnel Syndrome?

Abstract

Recent studies have demonstrated ultrasonography as a valuable tool for confirming the diagnosis of carpal tunnel syndrome. The objective of this study was to investigate sonographic parameters of the median nerve in patients diagnosed clinically with carpal tunnel syndrome. 185 wrists in 185 patients, 149 women (81%) and 36 men (19%), with a mean age of 59 years, with the clinical diagnosis of carpal tunnel syndrome were examined sonographically. We measured cross-sectional area (CSA) of the median nerve at the forearm and at the carpal tunnel inlet, as well as the height (a-p dimension) of the nerve at the tunnel inlet and in the narrowest site in the carpal tunnel. Moreover, in all patients the severity of the disease was assessed by the Levine questionnaire. A significant variability of sonographic data characterizing the median nerve was found: the mean CSA at the tunnel inlet was 17.6 mm2 (range: 7-36) and height of the nerve at the tunnel inlet was a mean of 2.7 mm (range: 1.3-4.5). No correlation was found between sonographic data and severity of the syndrome as expressed by the Levine scores. Sonography of the median nerve contributes little to the diagnosis of a clinically relevant carpal tunnel syndrome and its routine use is not justified.