Injury of the suprascapular nerve during arthroscopic repair of superior labral tears: an anatomic study.

HYPOTHESIS: The purpose of this cadaveric anatomic study was to investigate the risk of iatrogenic suprascapular nerve injury during the standard drilling techniques in arthroscopic superior labrum anterior-posterior (SLAP) repairs.

MATERIALS AND METHODS: Cadaveric shoulder girdles were isolated and drilled at the glenoid peripheral rim by use of standard arthroscopic equipment reproducing common drill locations and portal orientations for SLAP repairs. Drill hole depth was determined by the manufacturer's drill stop (20 mm), and any subsequent drill perforations through the medial bony surface of the glenoid were directly confirmed by dissection. The suprascapular nerve was then isolated to note the presence of any observable direct nerve injury from the drilling. The bone tunnel depth, subsequent distance to the suprascapular nerve, scapular height and width, and humeral length were also recorded.

RESULTS: Eighteen drill perforations through the medial glenoid wall occurred in 8 of 21 cadavers (38%). Twelve perforations occurred through anterosuperior drill holes with only one associated nerve injury. Six perforations occurred through low posterosuperior drill holes with four associated nerve injuries. Five of the six shoulders with low posterosuperior perforation also had an associated anterior perforation. No perforations occurred through high posterosuperior drill holes. Of the specimens, 5 had bilateral involvement (4 female and 1 male). Specimens with a perforation had a significantly shorter scapular height (P = .007) and humeral length (P = .01).

CONCLUSIONS: The suprascapular nerve is at risk for direct injury during arthroscopic SLAP repairs from penetration of the medial glenoid with arthroscopic drill equipment in cadavers.