Clinical Outcome of Endoscopically Assisted Mini-open Carpal Tunnel Release

Background: Carpal tunnel syndrome (CTS) can be treated surgically. Although the minimally invasive open surgical method is widely used, it is not possible to directly visualise the entire length of the carpal tunnel, especially the proximal end, which is on the side away from the skin incision. In this study, we performed a mini-open carpal tunnel release with endoscopic assistance to release the entire length of the carpal tunnel under direct vision and investigated the treatment outcomes. Methods: The surgical method included an incision of <= 2 cm in the palm, cutting of the transverse carpal ligament under direct vision and cutting of the forearm fascia under endoscopic vision. A uniquely designed sheath was used for the endoscopic resection. We investigated the sex, age, medical history, symptoms, examination findings, anaesthesia method, operation time, thenar motor branch variation, postoperative complications, presence or absence of pillar pain and final examination findings of the target patients. Results: A total of 100 hands (85 patients) were included. Anatomical variations of the thenar motor branches were observed in 19 hands. At the final follow-up, hand numbness improved in all patients, while mild numbness was observed in 25 hands. The abductor pollicis brevis muscle improved in all patients with paresis, but 8 of the 27 hands remained completely paralysed. Pillar pain was observed in 36 hands at 8 weeks postoperative, but the condition improved in all patients. The clinical outcomes of this study were good with no cases of major complications or reoperation. Conclusions: The minimally invasive open surgical method described here can be reliably used to release the forearm fascia proximal to the carpal tunnel. The thenar motor branch can also be confirmed under direct visualisation, making it a relatively safe and useful approach.