Changes in electrophysiological parameters after surgery for the carpal tunnel syndrome.

Carpal tunnel syndrome is a common condition, affecting mostly females. Nerve conduction studies are performed routinely for the diagnosis of carpal tunnel syndrome. Surgical intervention for release of the median nerve at the carpal tunnel is the treatment of choice. Few studies have looked at the improvement in the electrophysiological parameters after carpal tunnel release. This study compared the distal motor and sensory latencies, motor and sensory amplitudes, and sensory conduction velocities of the median nerves across the carpal tunnel in patients with the carpal tunnel syndrome preoperatively and postoperatively at 18 and 42 weeks, respectively. The results showed improvement in all the studied variables, except the distal sensory latency, 18 weeks after the surgery, whereas the distal sensory latency improved only at 42 weeks postoperatively. These findings denote the differential affection of the sensory and motor fibers in the carpal tunnel syndrome and confirm the value of nerve conduction studies in the evaluation of patients who do not improve or who have recurrence of their symptoms after carpal tunnel release.