When the deltoid muscle in the shoulder is paralyzed due to an upper brachial plexus injury, the person with the injury may be unable to move the shoulder. However, the person's triceps may still function, providing the ability to extend the arm. In this case, surgeons at the Center for Nerve Injury and Paralysis would perform a nerve transfer to restore function to the deltoid muscle.
Nerve transfers involve taking nerves with less important roles â€” or branches of a nerve that perform redundant functions to other nerves â€” and "transferring" them to restore function in a more crucial nerve that has been severely damaged.
For this type of shoulder paralysis, the centerâ€™s surgeons would make a single incision on the back of the arm to gain access to nerve branches that innervate the triceps and to the axillary nerve, which provides function to the deltoid muscle. The surgeons would then cut specific branches of the nerve that connects to the triceps and plug those in (transfer them) to the axillary nerve.
As only a portion of the nerves to the triceps are used for this procedure, patients will still be able to activate their triceps muscle and extend their arm after surgery. However, as they regain function from the nerve transfer, they also will be trained to use the triceps nerve to raise the arm up and out to the side. The brain then learns this trick, and you are able to move the shoulder simply by thinking about moving the shoulder.
Many similar nerve transfers are available for paralyzed shoulder muscles, and your surgeon will choose the most appropriate operation for your individual condition.
Recovery of function after nerve transfer is a long process. Patients generally see small signs of recovery three to six months after the operation, but in most cases, return of movement takes six to 12 months.