Background and purpose: Carpal tunnel syndrome is one of the most common causes of orthopedic referrals. Today, many surgeons tend to perform minimally incision surgery (MIS). This study was conducted to compare the results of open surgery and MIS by Smillie knife.

Materials and methods: In this prospective study, 72 patients (98 surgeries) with carpal tunnel syndrome were randomly divided into two groups of open surgery (n= 46) and MIS by Smillie knife
(n= 52). Clinical improvements were investigated in both groups according to the Boston Carpal Tunnel Syndrome Questionnaire (BCTQ). Electrodiagnostic improvement, duration of surgery, length of incision, and complications were compared between the two groups using paired-sample t-test, independent t-test, and Chi-square test.

Results: Paresthesia resolved immediately after surgery, except in two cases in open surgery group and one case in MIS group. After the surgeries, no difference was seen in electrodiagnostic parameters between the two groups. The number of individuals with pain was significantly lower in MIS group in week two and six after the surgery (P=0.035 and P=0.011 respectively). The Boston score showed no significant difference between the two groups after three months but after six months the score was significantly different in MIS group (P=0.515 and P=0.029 respectively). One patient in open surgery group suffered wound dehiscence after removal of sutures.

Conclusion: MIS is associated with quicker clinical improvements and because patients receive no anesthesia, it is superior to classic surgery.