Introduction: The open approach for releasing the A1 pulley shows high dissatisfaction rates. Percutaneous blind release is as an alternative achieving similar effectiveness and better results but the lack of visualization puts at risk the adjacent anatomy and its indicated only for the 3rd and 4th fingers. Recently, an effective percutaneous method for releasing A1 in every finger has been described assisted by the visualization with ultrasounds (US). Despite the reported safety, this US-technique poses a risk to the adjacent anatomy due the orientation of the blade. Our purposes were to develop a new percutaneous US-guided A1 release (USGAR) that lessens the risk to adjacent anatomic structures and to determine the precision, safety and efficacy of our USGAR.

Methods: To determine how to lessen the risk to adjacent structures, a descriptive study with a power-Doppler US (Logiq Book XP Pro 5–11 MHz, GE) was done in 100 fingers from 10 volunteers (3 females and 7 males; mean age 29,8 years, range 25–49 years). Measurements, on a transverse section of A1, included: lateral vascular angle (LVA), medial vascular angle (MVA), distance to lateral artery (DLA), distance to medial artery (DMA), lateral latitude (LL), medial latitude (ML), pulley thickness (PT) and synovial space width (SW).

A descriptive study was developed in 5 formaldehyde preserved cadavers, 50 fingers (3 men and 2 women, average age at time of death 60,6 years, range 52–81). US identification of topographic markings was followed by USGAR and open dissection. Measurements included real (RL) and US (UL) A1 length and distances from: markers to proximal (MP) and distal A1 edges (MD); markers to A2 (MA) and neurovascular (NV) bundles (MN); and from the surgical release to A2 (SA) and NV (SN). The length of any incomplete release (IR) and damage to adjacent structures were recorded. Mean values, Standard deviation and range were gathered. ANOVA was used to analyze differences (significant at p < 0.05).

Results: In our volunteers, we obtained the following values (degrees or mm): LVA, 20,9 +/− 14,03 (0/83,7); MVA, 23,3 +/−13,06 (0/61,5); DLA, 8,96 +/−3,08 (3,5/20,6); DMA, 7,59 +/−2,56 (3,7/16,8); LL, 2,38 +/−1,53 (−1/6,5); ML,: 2,56 +/−1,84 (0/10,8); PT, 0,79 +/−0,22 (0,2/1,5); SW, 0,33 +/−0,19 (0,1/0,9). Differences were not significant among fingers. In our group of cadavers our findings (mm) were: RL, 10,1 +/−1,36 (8/13); UL, 10,84 +/−1,38 (8/14); MP, −0,56 +/−1,3 (−5/2); MD, −0,19 +/−0,95 (−4/2); MA, 4,56 +/−1,64 (1/9); MN, 18,78 +/−4,11 (11/27); SA −1,08 +/−1,67 (−5/2); SN −13,17 +/−3,55 (−22/−6). There was a 1 mm IR in 2 fingers and minor puncture-like erosions in 6.

Conclussion: Our new method for USGAR minimizes the risk of accidental damage to adjacent anatomic structures. The method is precise, effective and safe in cadavers. This has set the bases for a clinical phase at our Institution.