Endoscopic carpal tunnel release: modification of Menon's technique and data from 191 cases.

ABSTRACT

PURPOSE: Endoscopic carpal tunnel release using Menon's technique has been shown to reduce recovery time, although previous studies have shown that there is still a considerable risk of nerve complications. The purpose of this study was to evaluate data from 227 hands of 191 patients who underwent releases with Menon's technique. TYPE OF STUDY Prospective study. METHODS: Endoscopic releases were performed as an outpatient intervention by one surgeon. Follow-up evaluations included were analysis of satisfaction, quantitative measurements of grip strength, return to work time, and complications. After the surgery on the first 50 hands in 41 consecutive cases, the technique was modified. Prospectively, changes in the technique are due to difficulties maintaining the knife within the center of the cannula's slot and a relatively high complication rate. In the modified technique, a 2.7-mm 25 degrees endoscope and a triangular diamond-tipped knife were used to allow for more room for the instruments and a more safe procedure. RESULTS: During the first month after the surgery, 91% of the patients had better subjective satisfaction scores and by 12 weeks, 81% obtained 75% to 100% or greater grip strength. Within 3 weeks, 70% of the patients had returned to work. Twelve of 50 hands operated on using the original technique had nerve disturbance diagnosed at follow-up. Three of these 12 patients developed reflex sympathetic dystrophy. One patient had partial median nerve injury that was repaired at the time of the index operation. There was no serious complication observed in 177 hands of 150 cases operated on using the modified Menon's technique, except one postoperative hypoesthesia along the long and ring fingers that improved with time. CONCLUSIONS: The procedure is suitable for outpatient surgery and the risk of inadvertent damage to the neurovascular structures can be dramatically reduced with the modifications to the technique. LEVEL OF EVIDENCE Level IV.