Percutaneous intrasheath ultrasonographically guided first annular pulley release: anatomic study of a new technique

The purpose of this study was to define in volunteers a safe area for performing a percutaneous intrasheath first annular (A1) pulley release under ultrasonographic guidance in cadavers for the treatment of trigger fingers. First, in 100 fingers of 10 volunteers, we used Doppler ultrasonography to determine the limits of the sectors enclosing structures at risk (arteries and tendons). From the synovial sheath's most volar point, we determined the relative position of the arterial walls and the distance to the flexor tendons. A scatterplot overlay of the arterial positions was digitally analyzed for determining the limits of the safe area. Second, we released the A1 pulley in 46 fingers from 5 cadavers, directing the edge of the cutting device toward our safe area from an intrasheath instrument position. The precision, safety, and efficacy of the release were evaluated by surgical exposure of the A1 and A2 pulleys and the neurovascular bundles. In our volunteers, we observed a volar safe area from +6.1° to +180°. Surgical precision was good in the cadavers, with no injuries to adjacent structures, a complete release in 44 fingers (95.7%), and an incomplete release of less than 1.6 mm in 2 fingers. This study determined a safe volar area for aiming surgical instruments from an intrasheath position for percutaneous ultrasonographically guided A1 pulley release. The technique can be performed safely in all fingers, but we suggest being cautious in the thumb and converting the surgery to an open procedure if ultrasonographic visualization is not optimal.