Failed endoscopic carpal tunnel release. Operative findings and results of open revision surgery.

From 1994 to 1997, 22 patients (24 wrists) underwent open revision carpal tunnel release for persistent carpal tunnel syndrome after a primary endoscopic release. The age range was from 21 to 77 years. At the time of revision surgery, 22 wrists had an incomplete release of the flexor retinaculum and two patients had median nerve transection (one partial and one complete). One patient had release of Guyon's canal and not the carpal tunnel. After the open revision carpal tunnel release, 20 patients returned to work with five patients returning to jobs of lighter duty. In addition, these 20 patients had significant improvement in symptoms. The remaining two patients had sustained a median nerve injury and did not return to work. One of these patients developed a painful neuroma in continuity of the median nerve which required vein wrapping with a saphenous vein graft. This study indicates that endoscopic release of the flexor retinaculum holds the same risks and complications as open release. Based on our study we believe that patients with persistent carpal tunnel syndrome after failed endoscopic flexor retinaculum release can be successfully treated with open release.