Short-term results of endoscopic (Okutsu method) versus palmar incision open carpal tunnel release: a prospective randomized controlled trial

Abstract

Purpose: The surgical techniques widely used in Japan for idiopathic carpal tunnel syndrome (CTS) are the Okutsu method of endoscopic carpal tunnel release (ECTR) and palmar incision for open carpal tunnel release (OCTR). However, no prospective randomized controlled trials (RCTs) have compared treatment outcomes between these two procedures. This RCT compared short-term outcomes between ECTR and OCTR for CTS.

Materials and methods: Subjects were 101 hands (79 patients) treated in the department. ECTR was performed on 51 hands (40 patients), and OCTR was performed on 50 hands (39 patients). For assessment items, the following patient-based outcomes were evaluated: 1) changes in subjective symptoms; and 2) impairment in activities of daily living. The following items were also evaluated by physicians: 3) abductor pollicis brevis-distal latency (APB-DL); 4) sensation; and 5) muscle strength. All these assessments were made in postoperative weeks 4 and 12.

Results: Recovery of muscle strength at postoperative week 4 was significantly better with ECTR (p< 0.05), but no significant differences were identified between groups in any of the other items. The ECTR group showed transient postoperative exacerbation of subjective symptoms in two hands (4%) and of APB-DL in three hands (6%). Comparison of hands with improved and exacerbated postoperative APB-DL in the ECTR group revealed significantly greater preoperative electrophysiological severity in exacerbated hands (p< 0.05). The cause of postoperative exacerbation with ECTR was considered to be transient nerve dysfunction resulting from the unique aspects of the ECTR procedure.

Conclusions: Compared with OCTR, ECTR offers superior recovery of muscle strength in the early postoperative period. At the same time, ECTR may carry a risk of transient nerve dysfunction in the early postoperative period. Caution must therefore be exercised when using ECTR for patients with severe electrophysiological findings.