Reoperation for carpal tunnel syndrome.

Although primary carpal tunnel release is usually successful, reoperation is needed in up to 3% of patients. Common indications of reoperation are previous incomplete surgery and postoperative fibrosis. Although most patients improve after reoperation, persistent systems are likely and failure is more frequent than after primary carpal tunnel surgery. Risk factors for failure following reoperation include the presence of an active Worker's Compensation claim, pain in the ulnar nerve distribution, and the absence of abnormality on preoperative EMG.