An adult brachial plexus injury is usually the result of trauma to the neck and shoulder areas and is usually much more severe than in children. The mechanism of injury is similar to that in children, a lateral traction injury to the brachial plexus nerves in the neck causing damage to the nerves and a loss of function. In adult injuries, timing is also imperative and the ultimate results depend on severity of injury and timing of intervention.
After recovering from the initial injury, patients are closely followed to monitor for return of function. If in two to three months, blunt injury victims do not show significant improvement in function then exploration and repair of the damaged brachial plexus is indicated. In penetrating trauma, earlier intervention is needed.
In exploring the brachial plexus, intraoperative EMG is performed in order to assess first if the injury is an avulsion or a rupture of the roots, and second if any of the neuromas found conduct electrical signal. Unfortunately, adult injuries tend to be more commonly associated with avulsion injury and therefore have a worse prognosis. Another disadvantage is the greater distance a repaired nerve must travel to get to the motor end plate in the adult in the 18 months or so before the connection dies. This means that muscles that are further away, such as those that control the fingers, even if repaired can run out of time. The result is that secondary reconstruction is almost always needed to regain maximum function in adults.
Secondary reconstruction depends greatly on the deficits of the injury. The most difficult area to reconstruct is shoulder function in a flaccid limb. Nerve transfers, muscle transfers, and tendon transfers have all been used to improve function and the specific combination of techniques used to repair an injury is customized based to the patient.
Significant functional improvement can be achieved, but it usually requires a number of surgeries over a long period of time. Research is making advances in nerve and muscle regeneration, and we are actively including our patients, with their permission, in any study that may provide them with additional function.