Carpal tunnel release has been performed in our institution on 378 patients (a total of 461 hands) since 1987. Of these operations, 175 were right-sided, 120 were left-sided, and 83 were bilateral. The technique used for the operations was outpatient microsurgery (with most patients under local anesthesia). During this surgery, a longitudinal incision of 3 cm was made; the incision never crossed the wrist flexion crease. Five patients had the recurrent thenar branch exit through the middle or ulnar part of the ligament, and in all these patients, the branch was preserved. Perioperative complications included four stitch abscesses managed on an outpatient basis and three wound infections for which the patients were admitted to the hospital for wound care and for intravenous administration of antibiotics. One wound dehisced after a steroid-dependent patient had fallen; this was primarily repaired; in another patient, a trigger finger developed 6 months after surgery. The mean time before the patients returned to work was 6 weeks (range, 2 d-16 wk). The mean follow-up for these patients was 37 months (range, 6-72 mo). In 332 patients, all painful dysethesias completely disappeared. In another 30 patients, marked improvement was seen in dysethesias, so that the overall improvement rate was 96%. Motor improvement occurred in 349 (97%) of 360 patients who had experienced motor weakness before surgery. In seven patients with bilateral symptoms, the symptoms in the contralateral side resolved after unilateral surgery. Eight patients had persistent incisional wound pain that required persistent medication and that delayed or prevented return to work; six of these patients were receiving workmen's compensation.(ABSTRACT TRUNCATED AT 250 WORDS)