Reducing Neurologic and Vascular Complications of Endoscopic Carpal Tunnel Release Using a Modified Chow Technique

Purpose: To reduce the rate of median nerve injury occurring during Chow's original 2-portal technique, we developed a modified procedure. The surgical technique was introduced, and the results were evaluated with regard to the clinical findings, nerve conduction studies, and Disabilities of the Arm, Shoulder, and Hand (DASH) score. Methods: We analyzed 119 hands of 119 patients with idiopathic carpal tunnel syndrome who underwent our procedure, wherein a cannula assembly was inserted after a partial division of both distal and proximal parts of the transverse carpal ligament through the entry and exit portals. Postoperative examinations, including evaluation of numbness, grip strength, pinch strength, tenderness over and around the wounds, and nerve conduction studies, were performed at 1 month (n = 119), 3 months (n = 119), 6 months (n = 102), and 12 months (n = 39). The DASH score was also evaluated preoperatively and at 3, 6, or 12 months postoperatively. The rate of structural damage to the median nerve, the tendon, and the artery was calculated. Results: The patients resumed their daily activities or work by 13 days postoperatively. Tenderness around the wounds was detected in 66% of patients by 3 months postoperatively. Numbness disappeared or decreased in 99% of patients by 6 months postoperatively. The DASH score was available for 82 patients, and it improved from 28.2 to 18.3 points postoperatively. Nerve conduction studies indicated a significant decrease in motor distal latency postoperatively. Temporal worsening of median nerve function was observed in 2 patients; however, no structural damage to the nerve, tendon, or artery was observed. Conclusions: We found no injury to the tendon or artery and no laceration to the nerve in all 119 patients. However, temporal worsening of median nerve function was observed in 2 patients. Level of Evidence: Level IV, therapeutic case series.