Anterior transfer of the long head of triceps nerve to the terminal part of the anterior division of the axillary nerve through two incisions: A cadaveric feasibility study.

Purpose: Restoring shoulder function after axillary nerve injury is always a challenge. Transferring a branch of the radial nerve destined to the triceps onto the anterior division of the axillary nerve has become the preferred technique. However, this is not always possible, especially when the axillary nerve is severely injured around the posterior part of the humeral neck. The purpose of this cadaver study was to assess the feasibility of transferring the nerve of the long head of the triceps through an anterior and lateral humeral neck tunnel, directly onto the branch of the anterior division of the distal axillary nerve where it enters the deltoid fibers, by two surgical approaches.

Materials and methods: This anatomical study was performed using 6 fresh cadavers (12 shoulders). A medial brachial approach was used to locate the radial nerve and its first branch, innervating the long head of the triceps. Then a second, transdeltoid approach was made to locate the end of the anterior branch near where it enters the deltoid fibers. The long head of the triceps nerve was transected as close as possible to the muscle, to provide the longest length possible. Then an anterior and lateral subdeltoid tunnel was made to retrieve this branch through the transdeltoid approach.

Results: The long head of the triceps nerve could always be sutured to the anterior branch of the axillary nerve. Given the 7-12 mm surplus length (mean, 8.8 mm), tensionless suturing was possible in an anatomical region amenable to easier microsurgery.

Discussion: Transfer of the long head of the triceps to the anterior branch of the axillary nerve through an axillary or posterior approach remains the preferred method for reinnervating the deltoid. However, in some patients, the axillary nerve is injured at or beyond the typical microsurgical suturing zone, which means that transfer cannot be accomplished under optimal conditions. For this reason, we suggest making the transfer more distally, using a dual approach that allows direct suturing of the long head of the triceps nerve onto the anterior terminal branch, which shortens the distance between the sutured nerve and the deltoid, and should improve outcome.