Carpal Tunnel Syndrome: A New Objective Evaluation Technique

Abstract

E Bigelow, M Bell. Carpal tunnel syndrome: A new objective evaluation technique. Can J Plast Surg 1998;6(2):99-103. Thumb abduction strength is impaired progressively in patients with carpal tunnel syndrome (CTS). In advanced cases abductor pollicis brevis (APB) weakness and wasting are evident. The APB muscle recovers power significantly after carpal tunnel release. A technique that objectively measures this function is described. The results of a study comparing 175 patients suffering from CTS with 132 controls are presented. No previous study has looked exclusively at the APB motor deficit preoperatively and at the postoperative recovery in CTS patients. Preoperatively, bilateral thumb abduction power was measured in patients with CTS by using a micrometer spring scale. The results were compared with those from a control group. A significant APB strength deficit was present in all CTS patients (P=0.001). A standard carpal tunnel release was performed by the same surgeon in all cases. The transverse carpal ligament was incised under direct vision with the use of an open technique. Thumb abduction strength was measured again four weeks postoperatively; significant recovery was observed in strength compared with the preoperative value (P=0.001). Thumb abduction power was, however, still lower than that of the control group (P=0.001). This test is a simple, inexpensive and reproducible way to evaluate the severity of CTS and to help diagnose patients with CTS objectively. It is a useful adjunct to monitor and follow CTS patients postoperatively.