gms | German Medical Science

Objectives/Interrogation: The axillary nerve (AN) is at risk of iatrogenic injury during arthroscopic shoulder procedures that use anchors or sutures in the anteroinferior or inferior margin of the glenoid (6-o'clock position). This injury most frequently occurs in a so-called "blind spot" that is located between the surgical exposure limits of the medial deltopectoral approach and the posterior approach to the AN. The aim of this study was to evaluate the feasibility of exploring the 6-o'clock position using a lateral deltopectoral approach, extended as needed with an anterior axillary approach. We hypothesized that 1) the lateral deltopectoral approach allows neurolysis of the AN at the 6 o'clock position, and 2) that an axillary extension of this approach enables sufficient exposure for AN repair, graft or nerve transfer.

Methods: Four axillary nerves were dissected combining the deltopectoral approach-medial to conjoint tendon (A), the deltopectoral approach lateral to conjoint tendon (B) and the axillary approach (C) in three sequences: A-B-C, B-A-C and C-B-A. After the first approach was completed the proximal and distal margins were marked. Additional exposures with the second and third approach and the 6-o'clock position were also marked. When the three approaches were completed, the AN was excised and the amount of exposed nerve with the three approaches was measured.

Results and Conclusions: The deltopectoral approach using the medial interval to the conjoint tendon did not allow exposure of the AN at the 6 o'clock position. This exposure was accomplished using the lateral interval of the deltopectoral approach and the axillary approach. The deltopectoral approach lateral to the conjoint tendon allowed 28-46% length of AN exposure, including the 6 o'clock position, but not to the level of the terminal branches. The axillary approach was able to expose the terminal branches of the AN (but not the nerve-muscle junction) and the 6 o'clock position of the glenoid. A combination of the 3 approaches exposed 81-94% of the total length of the AN.

The deltopectoral approach allowed visualization of the AN at the 6 o'clock position when explored lateral to the conjoint tendon. The achieved visualization allows the surgeon to assess continuity of the nerve at the 6 o'clock position, perform neurolysis, but not perform nerve repair at this site. If nerve repair with or without graft or a nerve transfer is attempted, a combination of the 3 approaches should be used with an axillary extension of the incision.