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Traumatic Brachial Plexus Injury


Definition

The brachial plexus (brachial means arm and plexus mean communication or meeting point) refers to the nerves that exit the cervical spine and pass down to the shoulder and arm. Five major nerves comprise the brachial plexus: C5, C6, C7, C8, and T1 (C refers to cervical [or neck] and T refers to thorax [or chest]). These nerve pass under the skin in the neck and axilla, where they are vulnerable to injury. When the neck and arm are forced away from each other during trauma (e.g., car accidents, motorcycle accidents, falls) the brachial plexus nerves can be stretched or torn apart. If the force is severe, these nerves can even be pulled away from the spinal cord where they originate. Damage to these nerves causes pain, numbness, and weakness in the shoulder, arm, and hand. The pain can be quite severe, and is often described at burning, pins and needles, or crushing. In general, the C5 nerve controls the rotator cuff muscles and shoulder function, C6 controls flexing the arm at the elbow, C7 partially controls the triceps and wrist flexion, and C8/T1 controls hand movements. Several patterns of injury occur, the most common is referred to as an Erb's palsy. This is when C5 and C6 are predominantly affected. These patients are unable to lift their arm or flex at the elbow. Severe atrophy can occur in the shoulder muscles. Another pattern of injury is when C8/T1 is mostly damaged. These patients have hand weakness and pain. Some finger movement may remain, however. The most severe type of injury is when the arm is completely paralyzed due to extensive brachial plexus injury.


Diagnosis A brachial plexus injury is diagnosed with a thorough history and physical examination. Imaging of the spine with either MRI or CT myelography is important for determining any detachment of the nerves from the spinal cord, which determines prognosis and treatment. Electrical testing also helps guide treatment and predict outcome, however, in general, it should not be performed until 3 weeks after injury. Direct imaging of the brachial plexus is usually not helpful with currently available techniques. It is important to see a physician who specializes in examining, diagnosing, and treating brachial plexus injury within the first few weeks after the accident.

Treatment Options In general, patients are observed for spontaneous recovery during the first 3 months after injury. Many patients regain some function during this time. Surgery is not immediately performed because many people may spontaneously recovery without treatment. Furthermore, delicate nerves that may have spontaneously recovered may be injured with early surgery. During this waiting period, pain is aggressively controlled and physical therapy is performed. Imaging of the cervical spine and electrical testing is also performed. No medication is currently available to hasten recovery. When paralysis remains at 3 months, and electrical testing does not indicate an early recovery, then exploratory surgery is often indicated. Recovering nerves are protected. Injured, non-functional nerves are exposed and examined with both a microscope and intraoperative electrical testing. When possible, injured nerves are repaired or replaced, which allows recovery. Repairing nerves with surgery gives them the opportunity to regenerate themselves. Nerve regeneration progresses about one inch per month. Therefore, even after successful surgery, it can take up to 6 to 12 months before the regenerating nerves reach their target muscle and for movement to occur. Surgery is usually scheduled between 3 and 6 months after injury. If you wait much longer than this then the chances of surgery working decreases with time. The exact timing and type of surgery is often different for