Cross-Sectional Area of the Median Nerve Characterized by Ultrasound in Patients With Carpal Tunnel Syndrome Before and After the Release of the Transverse Carpal Ligament

Abstract

The objective of this study was to evaluate the cross-sectional area of the median nerve by ultrasonography before and after release of the transverse carpal ligament in patients with carpal tunnel syndrome. An additional goal was to correlate the cross-sectional area following surgery with clinical symptoms. Eighteen patients and 22 wrists were evaluated. All patients underwent Paine’s surgical technique for release of the transverse ligament. Cross-sectional area was calculated from sonograms taken at the pisiform bone level pre- and postsurgery. Postsurgical measurements were made at 4, 8, 12, and 96 weeks. Before surgery, the mean cross-sectional area was 19.7 mm2. The results following surgery were as follows: 4 weeks, 20.1 mm2; 8 weeks, 17.4 mm2; 12 weeks, 15.5 mm2; and 96 weeks, 13.5 mm2. Three patients remained clinically symptomatic at the time of their last follow-up visit. Cross-sectional area of the median nerve tends to increase 4 weeks after surgery for carpal tunnel syndrome, compared with the measurements taken prior to surgery, and then progressively decreases. There was no evidence of postprocedure correlation between the cross-sectional area of the median nerve and clinical symptoms.