Effect of patient positioning in axillary nerve safety during arthroscopic inferior glenohumeral ligament plication.

PURPOSE: To evaluate the risk of injuring the axillary nerve during an inferior glenohumeral ligament (IGHL) plication and finding out whether shoulder position (either beach chair position or lateral decubitus position) has any effect in this risk.

METHODS: The axillary nerve (AN) was identified through a 3-cm posterior incision in 12 cadaveric shoulders. Under arthroscopic visualization, a curved indirect suture-passing device was placed through the posterior and anterior bands of the IGHL. The distances between the device and the AN were measured with the shoulder specimen placed at simulated lateral decubitus position and beach chair position.

RESULTS: There were no cases of nerve injury nor the suture-passing device came closer than 10 mm to the nerve. There was an increase in the injury risk to the AN when inserting the device at the posterior band of the IGHL in the beach chair position [median 13 mm (range 10-21 mm)] compared to the risk in the lateral decubitus position [22.5 mm (20-26 mm), significant differences, p < 0.001]. When the device was inserted at the anterior band of the IGHL, there were no significant differences (n.s.) [lateral decubitus position: 18 mm (14-24 mm) vs. 16 mm (13-18 mm)]. When comparing differences between bands, there were no differences in the beach chair position, but the risk was lower for the posterior band in the lateral decubitus position (p < 0.001).

CONCLUSIONS: During plication of the posterior band of the IGHL, the risk is higher if the procedure is performed in the beach chair position. The posterior plication is safer than the anterior plication in lateral decubitus position.

CLINICAL RELEVANCE: This study helps the surgeon to better understand the proximity of the nerve to the IGHL and to highlight that the risk of nerve injury during capsular plication might be reduced in the lateral decubitus position.