Nerve injuries can be caused by different reasons, including car and bike accidents, sports accidents, falling from a height such as construction accidents, and surgeries for head and neck cancer. Once a nerve is cut from a muscle, it has to be reinnervated within about 18 months before the muscle atrophies. Since nerves only generate one millimetre per day, sometimes they cannot regenerate and reach the muscle before it wastes away.
A nerve transfer is a surgical procedure used when a patient has a nerve injury causing complete loss of muscle function or sensation.
Nerve injuries are best-treated immediately after the injury because nerve grafting will most likely be needed. Nerve injuries that are surgically treated by nerve grafting usually have protracted recovery. The nerve for grafting is usually harvested from the leg.
Nerve transfers involve nerves with less important roles or branches of a nerve that perform redundant functions being transferred to other nerves to restore function in a more crucial nerve which is severely damaged.
Nerve transfer surgeries are usually required when a nerve end has lost function, or when nerve reconstruction requires extremely long nerve grafts. In the upper extremity, nerve transfers are commonly done for injuries of the brachial plexus, (nerves near the neck and shoulder). Other indications of needing a nerve transfer include complex injury to the peripheral nerves, associated with fractures, dislocations, lacerations and injuries from projectiles and cancers.