Medial perforation of the glenoid neck following SLAP repair places the suprascapular nerve at risk: a cadaveric study

Background: Although suprascapular nerve injury after SLAP (superior labrum anterior to posterior) repair has rarely been reported, the direction of anchor insertion is toward the suprascapular nerve. The purpose of this study was to evaluate the risk of suprascapular nerve injury during the drilling and anchor insertion for anterior SLAP repair. Materials and methods: Twelve cadaveric shoulders were mounted in a lateral decubitus position (to mimic actual surgery) and 1 suture anchor for anterior SLAP repair was inserted arthroscopically from the anterior portal at 00:30-1:00 o'clock in right shoulders (11-11:30 in left). Then, cadaveric shoulders were dissected to determine the pathway of suprascapular nerve, the location of suture anchor, and anchor perforation of the glenoid wall. Distances from suprascapular nerve to suture anchor tips (which perforated medial cortex of glenoid)-that is, nerve-anchor interval (NAI)-were measured. Glenoid widths and heights were also measured to evaluate the correlation between glenoid areas and NAI. Depth of drilling was also determined. Results: All suture anchors perforated the glenoid wall. Mean drill depth was 14.2 (+/- 2.8) mm and mean NAI was 3.1 (+/- 2.7) mm. In 4 shoulders, suture anchor tips contacted the suprascapular nerve. The mean height of the glenoid surface was 30.0 mm (+/- 2.5), its mean width was 22.9 mm (+/- 1.9), and its mean area was 2164.3 mm(2) (+/- 334.1). No correlation was found between glenoid areas and NAI (P = .277). Conclusion: Suprascapular nerve lies very close to drilling sites and suture anchors during arthroscopic anterior SLAP repair. The present study cautions that care should be taken when anterior anchors are being inserted. Level of evidence: Anatomic Notes. (C) 2011 Journal of Shoulder and Elbow Surgery Board of Trustees.