Carpal tunnel syndrome: indication for surgical treatment based on electrophysiologic study.

A prospective study of 50 hands from 45 consecutive patients surgically treated for idiopathic carpal tunnel syndrome was conducted to determinate the recovery capacity of the median nerve after open surgical release. Subjects were evaluated by clinical history, physical examination, and electrophysiologic testing. Motor and sensory terminal latencies and motor and sensory conduction velocities were examined before surgery and 2 weeks, 2 months, and 6 months after surgical decompression. All patients showed improvement of postoperative electrophysiologic values; the amount of improvement was dependent on the degree of preoperative impairment. Complete restoration of clinical and electrophysiologic nerve function was observed only in patients with mild carpal tunnel syndrome.