Transfer of the rhomboid nerve to the suprascapular nerve: An anatomical feasibility study

Paralysis of the suprascapular nerve, in partial injuries of the brachial plexus, most often warrants a nerve transfer. Transfer of the spinal accessory nerve to the suprascapular nerve is performed most often. We propose to directly transfer the nerve of the rhomboid muscles (branch of the dorsal scapular nerve) to the suprascapular nerve in the supraspinatus fossa. This anatomical study included 10 shoulders. Dissection of the suprascapular nerve and the branch of dorsal scapular nerve to rhomboid muscles (rhomboid nerve) was performed through a posterior approach. Once the nerves were freed, the possibility of suturing the two nerves together was evaluated. Tensionless suture of the rhomboid nerve to the suprascapular nerve was possible in all shoulders in this study. In addition, the diameter of the two nerves was macroscopically compatible: the average diameter of the rhomboid and suprascapular nerve was 2.9 and 3mm, respectively. The diameter of the rhomboid nerve is more suitable than that of the spinal accessory nerve for a transfer to the suprascapular nerve. Moreover, the spinal accessory nerve is preserved in this technique, thereby preserving the function of the trapezius muscle, which could be used for muscle transfer if the nerve surgery fails. In addition, use of the rhomboid nerve allows the suture to be performed downstream to the suprascapular notch and avoids poor results linked to multilevel injuries of this nerve. Finally, if the posterior approach is extended laterally, associated transfer of the nerve to the long head of the triceps brachii to the axillary nerve is also possible. Rhomboid nerve transfer to the suprascapular nerve is anatomically possible. A clinical study will now be necessary to confirm this hypothesis and set out preliminary results.