Relation of preoperative nerve-conduction values to outcome in workers with surgically treated carpal tunnel syndrome.

Ninety-three workers having undergone carpal tunnel decompression were assessed 16 to 100 months after surgery. The results of outcomes pertaining to symptoms of numbness, nocturnal awakening, and pain as well as job status were compared to the patients' preoperative nerve conduction study findings. Significant differences in preoperative nerve-conduction values (NCVs) were found between groups reporting poor results and those reporting good results. These differences were such that those reporting poor results had more normal NCVs. Those reporting job changes because of carpal tunnel syndrome also had more normal preoperative nerve-conduction results. Data indicate that those with terminal latencies 1 ms greater than the testing facility normal value or with sensory conduction velocity 10 ms less than the facility norm were more likely to benefit from surgery. This study suggests the need for caution when considering carpal tunnel surgery in workers with normal or near normal nerve-conduction results.