Neurologic complications of shoulder surgery.

Nerve injuries do occur during shoulder surgery. Studies of regional anatomy have defined the nerves at risk. The suprascapular nerve may lie no more than 1 cm from the glenoid rim. The axillary nerve may run no more than 3 mm from the inferior shoulder capsule and passes near the lower extent of the deltoid split used as an approach to the shoulder. The musculocutaneous nerve passes as near as 3.1 cm below the coracoid. Interscalene nerve block is not commonly implicated in nerve injuries. Three-dimensional knowledge of nerve anatomy is essential during arthroscopy for safe portal placement and trochar direction. Nerve injuries are reported to occur in 1% to 2% of patients undergoing rotator cuff surgery, 1% to 8% of patients undergoing surgery for anterior instability, and 1% to 4% of patients undergoing prosthetic arthroplasty. Surgical techniques for the shoulder are improving and nerves seldom are injured by direct laceration or incorporation in suture repair. Commonly, the nerve injuries occur secondary to traction or contusion. These are avoided best by careful attention to patient positioning, retractor placement, and arm manipulation during surgery. Because of the contemporary nature of these nerve injuries, observation is almost always the treatment of choice, with delayed electrodiagnostic testing should nerve recovery not occur within a 3 to 6-week period.