Ultrasound-guided thread versus ultrasound-guided needle release of the A1 pulley: a cadaveric study.

Purpose: To assess and compare two ultrasound-guided, minimally invasive procedures to release the A1-pulley (needle release and thread release) regarding efficacy and safety in an anatomical specimen model.

Materials and methods: Twenty-one ultrasound-guided needle releases and 20 ultrasound-guided thread releases were performed on digits of Thiel-embalmed anatomical specimens. A scoring system was developed to assess ultrasound visibility, intervention outcome (incomplete, almost complete, or full transection of the A1 pulley), and injury to adjacent structures (neurovascular structures, tendons, A2 pulley). Statistical analysis was performed to compare the score of the two groups (group 1: needle release,group 2: thread release). A P-value of ≤ 0.05 was considered significant.

Results: Needle release was completely successful in 15 cases (71.5%), almost complete release was achieved in four cases (19%), and incomplete transection occurred in two cases (9.5%). Thread release was completely successful in 17 cases (85%), and almost complete transection was observed in the remaining three cases (15%). In both procedures no neurovascular structures were harmed. Slight injury of flexor tendons occurred in two cases (9.5%) in needle release and in five cases (25%) in thread release. There were no significant statistical differences between the groups regarding ultrasound visibility, intervention safety and outcome, (P > 0.05).

Conclusion: Ultrasound-guided needle release and ultrasound-guided thread release have similar success of release, both being effective and safe techniques for the release of the A1 pulley.