I have so many questions, I don't know where to start. My son hurt his arm in a waterskiing accident. Evidently the boat jerked his arm so hard, a nerve pulled away completely. They are talking about doing a nerve transfer from the pectoral muscle in his chest. If they do that, how will he use the chest muscle?
Trauma to the upper arm during accidents can result in avulsion (complete tear) of the brachial plexus. The brachial plexus is a group of nerves that start at the spinal cord in the neck area. At this level, the nerves are called spinal nerve roots. The nerve roots branch out and form the three main nerves to the arm.
In the basic nerve transfer procedure, the selected pectoral nerve is divided on one side and then surgically attached to the torn nerve. The nerves are close enough to the area of damage that re-routing them isn't too difficult. The closer the nerve is placed to the muscle target, the faster the recovery will be. This is important because if a nerve pathway isn't used, and the muscle doesn't contract, both soft tissues start to atrophy (waste away).
Pectoral nerves are used for several reasons. The nerve is broken down into several parts or segments. Usually, not all segments are destroyed. So there is some part of the pectoral nerves that are still working. At the same time, there is segmental innervation of the pectoralis major (chest) muscle. Segmental innervation means that more than one nerve controls the muscle. If one part of the nerve plexus is torn, another part can be used to signal the muscle to contract.
The pectoral nerves also have a large number of motor fibers. This increases the chance of success for reinnervation of the affected muscles without losing nerve function to the donor muscle.
The placement of nerve transfers and grafts for brachial plexus injuries depends on where the nerve root was ruptured and how severe the tear was. With the right placement of nerve graft or nerve transfer, new nerve fibers will grow back to the place where the nerve was damaged.