Measurement of pressure in the carpal canal before and after endoscopic management of carpal tunnel syndrome.

In forty-six patients who had carpal tunnel syndrome, a technique of continuous infusion, given under local anesthesia and without a pneumatic tourniquet, was used to measure pressures in the carpal canal before and after endoscopic release of the transverse carpal ligament (retinaculum flexorum manus). Pressures were similarly measured in sixteen subjects in a control group. The mean preoperative pressures were significantly higher in the patients who had carpal tunnel syndrome than in the patients in the control group when the pressures were measured under four conditions: with the wrist in the resting position, with active grip, and with maximum passive extension and flexion of the wrist. The mean pressures improved significantly postoperatively and were in the range of values that were found under each condition for the control group. Measurement of pressure in the carpal canal before and after operation may be useful in diagnosing carpal tunnel syndrome and in determining the effectiveness of endoscopic management.