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

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.

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.

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.

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.

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.