Injury to the plexus nerves may occur with varying degrees of severity. The location of the injury is the overriding concern in developing a reconstructive plan. The least severe injury occurs when a nerve is stretched without causing a tear in either the axon or the sheath that covers the nerve. This is a neuropraxic injury and will allow a faster recovery that may not require surgical intervention. An avulsion, the most severe injury, occurs when the nerve root has been avulsed, or torn from the spinal cord. Experience has taught us that primary nerve graft surgery is not useful to correct avulsions. A rupture is a tear in the nerve root after it exits from the spinal cord. Primary nerve grating may be helpful in treating ruptures.
An obstetrical brachial plexus injury occurs about once out of every 1,000 births. The cause of these injuries has been a topic of much debate. However, most experts in the field agree that the cause is due to excess lateral traction (pulling) on the head of the infant away from the shoulder during the birthing process. The traction causes varying injuries to the nerve roots that can cause an interruption in nerve signals. The child is left with a partial or complete paralysis to his or her upper extremity.
Much research into the field of brachial plexus injuries has shown that a majority of patients who suffer these injuries (approximately 80%) will recover function to their arms without need for surgical intervention. These patients are initially treated with physical therapy and close monitoring. If certain milestones in functional recovery are met, these patients may need only therapy and strengthening exercises to recover completely. However, 20% of patients who do not recover function to certain muscle groups will require surgery. Our experience has shown that when that surgery is done early, patients recover more function. It is therefore very important that when a patient is diagnosed with a brachial plexus injury that the patient be evaluated as soon as possible by an experienced team.
Diagnosis of a brachial plexus injury is usually made when examining a newborn who cannot move his or her upper extremity. When a child has a suspected injury, it is critical that her or she be evaluated by an expert to attempt to determine the extent and location of the injury. Other signs such as a Horner’s Syndrome, facial palsy, hoarseness, and difficulty breathing may also help in assessing the extent of the injury.
The initial presentation can vary from the classic Erb’s palsy posture that signifies an upper root injury of C5-C6+/-C7. These patients have internal rotation and adduction of the shoulder, elbow extension, forearm pronation, and wrist flexion. A global injury involves the C5-T1 nerve roots where the patients present with a completely flail limb and claw hand.