Subcutaneous local anesthesia versus intravenous regional anesthesia for endoscopic carpal tunnel release: a randomized controlled trial

Abstract

This study compares the effectiveness of subcutaneous infiltration of a local anesthetic agent (LA) versus intravenous regional anesthesia (IVRA) during endoscopic carpal tunnel release. Forty-four patients suffering from severe symptoms restricting normal daily activities-such as persistent loss of feeling in the fingers or hand, or no strength in the thumb in spite of prolonged nonsurgical treatment-and with electromyographically proven carpal tunnel syndrome were enrolled in this study. All underwent endoscopic carpal tunnel release. Twenty-two patients had an endoscopic release of the median nerve under LA (LA Group). The other 22 patients underwent the surgery after intravenous induction of regional anesthesia (IVRA Group). The operating room in-out time and tourniquet time were evaluated in both groups. The patients were also asked to evaluate the pain associated with the tourniquet during surgery using a visual analog scale. The Michigan Hand Outcomes Questionnaire was used to assess the functional outcome preoperatively and at both 2 weeks and 6 months postoperatively. One patient in the LA Group needed an additional application of prilocaine, whereas 3 patients in the IVRA Group needed additional LA and 1 of these required propofol. The tourniquet time and operating room time were significantly lower in the LA Group (p = 0.01 for both). There were no complications related to the endoscopic surgery. The Michigan Hand Outcomes Questionnaire did not show significant differences between the groups at either postoperative follow-up examination. Endoscopic carpal tunnel release with subcutaneous infiltration of LA was well tolerated and effective. Injection-associated problems such as increased thickness of the synovial layer or impaired endoscopic view did not occur.