Ultrasound-guided minimally invasive thread release of carpal tunnel: a cadaveric study

Abstract

Purpose: Thread release of the carpal tunnel is the most recent of several minimally invasive ultrasound-guided carpal tunnel release techniques. The purpose of this article is to provide a step-by-step guide for minimally invasive, ultrasound-guided thread release of the carpal tunnel focused on transecting the transverse carpal ligament with minimal damage to the palmar aponeurosis on anatomical specimens. Methods: Fifteen ultrasound-guided carpal tunnel thread releases were performed on the wrists of soft-embalmed anatomical specimens, which were dissected immediately after the intervention. The procedures were performed by two musculoskeletal radiologists with 25 and 8 years of experience, respectively, in interventional radiology. Ultrasound visibility, completeness of transection, and damage to surrounding structures were evaluated on a score from 1 to 3. Results: We achieved a complete transection of the transverse carpal ligament in 11 of 15 interventions (73%) and an incomplete transection in the remaining four (27%). No neural or vascular structures were harmed. In two cases (13%), there was irrelevant damage to flexor tendons. The ultrasound visibility was rough in five specimens (33.3%), moderate in five (33.3%), and optimal in five (33.3%). Essential structures were delineated in all cases. Conclusion: Thread release of the carpal tunnel leads to only minimal damage to skin, as well as structures within the carpal tunnel and the palmar aponeurosis, promising a low amount of postinterventional complications. Relevance statement: Our study showed that minimally invasive ultrasound-guided thread release of the carpal tunnel is a feasible approach in the anatomical model. The results may provide a basis for further research and refinement of this technique.