Evaluation of Risk to the Suprascapular Nerve During Arthroscopic SLAP Repair: Is a Posterior Portal Safer?

Abstract

The purpose of this study was to compare the risk of glenoid perforation during SLAP repair for suture anchors placed through an anterolateral portal versus a posterolateral portal of Wilmington. Ten bilateral cadaveric shoulders were randomized to suture anchor placement through an anterolateral portal on one shoulder and a posterolateral portal on the contralateral shoulder. Anchors were placed into anterior, posterior, and far posterior positions on the glenoid rim (1 o'clock, 11 o'clock, and 10 o'clock positions for right shoulders). The shoulder was then dissected, and the distance from the suture anchor tip to the nerve was measured if perforation occurred. The maximum load and failure mechanism of each anchor was assessed with a materials testing system machine. Only 2 of 20 anchors placed in the posterosuperior glenoid through the posterolateral portal perforated compared with 16 of 20 of the anchors placed through the anterolateral portal (P < .05). The mean distance from the perforated anchor tip to the suprascapular nerve was 2.5 ± 1.4mm for the anterolateral portal and 4.4 ± 0.6mm for the posterolateral portal (P= .18). We did not observe a significant difference in biomechanical strength (P > .05). There is a high rate of glenoid perforation in close proximity to the suprascapular nerve when placing anchors in the posterosuperior glenoid through an anterolateral portal. Use of the posterolateral portal results in a much lower incidence of glenoid perforation for anchors placed in the posterosuperior glenoid, but there is a higher risk of glenoid perforation for an anchor placed in the anterosuperior glenoid from the posterolateral portal. There is a higher risk of injury to the suprascapular nerve when suture anchors are placed in the posterosuperior glenoid through an anterolateral portal compared with a posterolateral portal for SLAP repair.