Ultrasound evaluation of patients with carpal tunnel syndrome before and after endoscopic release of the transverse carpal ligament.

To evaluate the cross-sectional area of the median nerve using ultrasound in carpal tunnel syndrome patients before and after endoscopic intervention.Twenty patients with carpal tunnel syndrome (15 women and five men; mean age 55 years) were prospectively evaluated. Informed consent was obtained from all participants. The study was approved by our Institutional Review Board (IRB). Median nerve cross-sectional area was evaluated at the proximal level before and at 4, 8, and 12 weeks after endoscopic release of the transverse ligament. In the present study, the median nerve cross-sectional area cut-off point was 10 mm(2). Repeated measures analysis of variance test (ANOVA) was applied to compare the reproducibility of ultrasound measurements before and after intervention.The mean cross-sectional area of the median nerve was 15 mm(2) (SD+/-2.1) before surgery; and 11.1 mm(2) (SD+/-3); 9.2 mm(2) (SD+/-2); and 8.6 mm(2) (SD+/-1.6) at 4, 8, and 12 weeks after surgery. Repeated measures analyses of variance were found to be statistically significant (p<0.001).The results of the present study demonstrated that there was a decrease in the cross-sectional area of the median nerve after the release of the transverse carpal ligament.