Four muscles play an important role in moving the shoulder. When an upper brachial plexus injury limits the ability to bring the arm up and rotate it out, surgeons at the Center for Nerve Injury and Paralysis will examine whether the supraspinatus and infraspinatus muscles were affected by the injury. If so, they can perform a nerve transfer to restore function to these muscles.
Nerve transfers involve taking nerves with less important roles â€” or branches of a nerve that perform redundant functions to other nerves â€” and â€śtransferringâ€ť them to restore function in a more crucial nerve that has been severely damaged.
In this type of nerve transfer, the centerâ€™s surgeons will often cut part of the distal spinal accessory nerve, which innervates the muscle that allows you to bring your shoulder blades together (as in a military posture), and plug it in (transfer it) to the suprascapular nerve, which provides function to the supraspinatus and infraspinatus muscles. The supraspinatus muscle works with the deltoid muscle to bring your arm up, and the infraspinatus muscle rotates it out.
Patients will still be able to move their shoulder blade after surgery. However, as they regain function from the nerve transfer, they also will be trained to use this nerve that used to bring the shoulder blades together to now bring the arm up and rotate it out to the side. The brain then learns this trick, and you are able to move the shoulder as you wish simply by thinking about moving the shoulder.
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.