Minimally Invasive Carpal Tunnel Release: A Technical Note and a 20-Year Retrospective Series

Introduction The surgical treatment of carpal tunnel syndrome (CTS) has been enriched, during the last years, by different minimally invasive techniques to decompress the median nerve at the wrist as the endoscopic approaches or modified open technique. However, controversy remains about their safety and complication rate. We present the results of our minimally-invasive technique to median nerve release at the wrist. We will discuss the instrumental preoperative assessment, surgical steps, post-operative management, and complications. Methods We retrospectively reviewed clinical and neurophysiological data of all patients admitted at our institution between January 2001 and December 2020 for CTS surgery. The technique, performed under local anesthesia, is based on a single, small, linear transverse incision proximal to the wrist fold. After unsharpened dissection of subcutaneous tissues, a grooved guide is inserted in a slightly medial direction towards the fourth finger; this strategy prevents possible damages of nerve branches that could originate at this level. A second small incision over the guide's tip allows a wide corridor in the context of the ligament. The carpalotome is then inserted into the guide; the two minor wounds are closed with 5-0 prolene sutures. The final result is a wide release of the nerve. Results A total of 1568 operations on 1371 patients were performed using the described technique at our institution. The patients' cohort showed a higher prevalence of women (68%), with a mean age of 56.4 years (range 24-88 years). Paresthesia and numbness of the first three fingers were the most frequent signs and symptoms. All patients were submitted to a preoperative electrophysiological evaluation, which revealed the typical signs of CTS in most patients. The US evaluation of the median nerve at the wrist was a more recent introduction, dating from 2018. In 47 patients, despite an electromyography (EMG) not showing marked neurophysiological signs of severe CTS, the ultrasonographic evaluation was strongly consistent with the clinical diagnosis. In such patients, carpal tunnel release determined the resolution of symptoms. In 99.8% of total cases, we obtained a complete symptoms remission, with the disappearance of acroparesthesia and numbness. Conclusion The use of this technique has become widespread at our institution due to fewer local complications, a very low rate of recurrence, faster functional recovery, and reduced surgical time if compared to traditional open surgery and to endoscopic release too.