Ultasonographic indicators of carpal tunnel syndrome demonstrate reversibility following carpal tunnel release

Background: The objective of the present study was to use ultrasound examination to determine the cross-sectional area (CSA) of the median nerve and quantify transverse sliding motion during finger movements in patients with carpal tunnel syndrome (CTS). Method: CSA and transverse sliding motion were compared between 15 cases with bilateral CTS (30 hands; 3 men, 12 women; average age: 65.7 years) and a control group (30 hands) of ageand sex-matched healthy individuals. Furthermore, 13 hands of 12 patients who underwent open carpal tunnel release (2 men, 10 women; average age: 62.3 years) were assessed and compared before and after surgery. Results: The mean CSA was larger in the CTS group (16.9 mm2) than in the controls (10.0mm2), whereas transverse sliding motion was significantly higher in controls (6.6 mm) than in the CTS group (4.9 mm). The 12 patients with CTS who underwent surgery showed a mean preoperative CSA of 19.1mm2 that declined significantly to 14.2 mm2 postoperatively, and the mean transverse sliding motion increased from 3.2 mm preoperatively to 5.0 mm postoperatively. Conclusion: Combining CSA and transverse sliding motion as observed in ultrasound examination can improve CTS diagnosis. Increased CSA and decreased transverse sliding motion noted at the median nerve in the wrists of patients with CTS are partially reversible by open carpal tunnel release. Correspondence to: Ryusuke Osada, Department of Orthopaedic Surgery, Faculty of Medicine, University of Toyama, Sugitani, Toyama-City, Japan; Tel: +81-76-434-7353; Fax: +81-76-434-5035; E-mail: osa97@med.u-toyama.ac.jp