Traumatic Brachial Plexus Injury

Definition

CT myelogram revealing a
small fluid collection indicating
rootlet avulsion from the spinal
cord (above). Fluid collections are
also seen near other spinal
nerves (small arrows, lower image).

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

An example of a severe brachial
plexus injury where C5 and C6
were non-functional, C7 was
avulsed from the spinal cord
(lifted in air), and C8/T1 were
damaged but partially functional
based on intraoperative nerve
action potentials.

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 each patient. Therefore, it is important for the patient to be evaluated early so that they may consider all of their treatment options.

Despite how well the surgery goes, the chance of recovery is somewhat uncertain. In addition to factors we do not understand, surgical success depends on the type of injury, the nerve injured, the age of the patient, motivation of the patient, and timing of repair. On average, there is a 50% chance surgery for each nerve will allow movement to return. This number may be as high as 90% for certain nerves and injuries. Your surgeon will provide you with an estimate about your chances of recovery. A "success" is defined as strength against both gravity and some resistance. In general, greater the distance a nerve has to regenerate, the less likely there will be a good recovery.

Surgery

Brachial plexus exposed (above)
in an adult with Erb's palsy
(shoulder and arm flexion
weakness). The upper trunk
(C5/C6) was heavily scarred and
nonfunctional (asterisk). Therefore,
it was removed and replaced with
multiple sural nerve grafts (below).

Three general types of brachial plexus surgery are performed:

• Erb's palsy repair (shoulder/elbow weakness)
• Complete brachial plexus reconstruction
• Isolated nerve transfers

Each patient may undergo a combination of procedures.

Erb's palsy surgery requires an incision along the side of the neck and/or the clavicle. The injured C5 and C6 nerves are identified and examined. Depending on the injury, one or more of the following is performed (see technologies and techniques available section): scar tissue is removed, the nerves are re-attached directly or with nerve grafts from the leg, or nerve transfers are performed. This surgery takes about four to six hours.

Severe injuries require a complete exposure of the brachial plexus. Although muscle and bone are preserved, the incision can be long, passing from the neck and over the shoulder. The nerves are examined and reconstructed with multiple nerve grafts and transfers. This surgery can take up to 8-12 hours.

When nerves are found detached from the spinal cord on preoperative imaging, then select nerve transfers away from the site of injury may be recommended. The incisions for these transfers are often placed above the clavicle, behind the shoulder, under the arm, or near the wrist. Your average nerve transfer takes about 90 minutes per nerve transferred. Although certain brachial plexus techniques are associated with postoperative pain (e.g., intercostals nerve transfers), in the majority of patients incisional pain is minimal. Nerve pain before surgery may or may not improve immediately after surgery. More commonly, nerve pain slowly improves as the nerves regenerate.

Complications

A branch to the functioning long
head of the triceps was cut and
attached to the nonfunctioning
axillary nerve to allow this patient
to once again lift their arm. This
is an example of a nerve transfer.

Although complications are uncommon, they can occur. A frank discussion with your surgeon prior to surgery is mandatory. Because of long surgery and large incisions, wound infections may occur in some patients. Damage to important arteries and veins going to the arm may occur, which can lead to loss of limb. Fortunately this is so rare it hardly ever occurs. Additional numbness near the neck or chest may occur, but this usually goes away in a number of months. Additional paralysis is possible, but this is rare considering any functioning nerves are either not exposed, or operated on very gently. Trouble breathing, especially when exercising, may occur after surgery and can be related to new diaphragm weakness, fluid on the lung, or air compressing the lung. The latter two of which may require chest tube drainage. The wound is often mildly swollen for a few weeks after surgery. This is normal and goes away with time. If sural nerve grafts are taken from the legs, then a patch of numbness on the outside of the foot almost always occurs, even though some patients do not notice it. This numbness may diminish over time. Because the sural nerve carries no motor fibers, foot paralysis does not occur after removing the nerve graft.

Day of Surgery

All brachial plexus surgery is performed under general anesthesia with intraoperative electrical testing and microscopic magnification. You should not eat or drink after midnight the day before surgery. Medications may be taken with a sip of water the morning of surgery. You wake in the operating room and may see your family an hour later in the recovery room. Depending on the extent of surgery, you may discharged the same day, or a few days later. Pain is well controlled and you are encouraged to sit in a chair and even walk within the first day after surgery. This movement prevents muscle spasms, which reduces pain.

Recovery

During the first two weeks after surgery you wear a sling to protect the arm and let the wound heal. Pain medication is prescribed as needed. One week after surgery you visit your surgeon who checks your wound and removes any sutures. After about two weeks, physical therapy is prescribed. For the first three months, therapy concentrates on shoulder and elbow range of motion. Immediately after surgery your paralysis should be the same. However, when movement eventually returns, strengthening exercises are performed. Recovery often takes one year or longer.

Kienbocks Disease- A cause of slow wrist pain

What is Kienbock’s Disease?

Kienbock’s disease, or avascular necrosis of the lunate, is a condition in which the lunate bone, one of eight small carpal bones in the wrist, loses its blood supply, leading to death of the bone.  The lunate is a central bone in the wrist, important for proper movement and support of the joint. The lunate, along with the adjacent bones on either side of it, the scaphoid and triquetrum, make up the proximal carpal row. This row of bones articulates with the 2 forearm bones (the radius and ulna), to form the portion of the wrist that provides the most motion.  Damage to the lunate can lead to pain, stiffness, and in late stages, arthritis of the wrist. Kienbock’s disease is most common in men between the ages of 20 and 40 and rarely affects both wrists.

What causes it?

There is probably no single cause of Kienbock’s disease. Its origin may involve multiple factors, such as the blood supply (arteries), the blood drainage (veins), and skeletal variations. Skeletal variations associated with Kienbock’s disease include a shorter length of the ulna, one of the forearm bones, and also the shape of the lunate bone itself. Trauma, either single or repeated episodes, may possibly be a factor in some cases.  Kienbock’s disease can be found more commonly in people who have medical conditions that affect blood supply, and it is also associated with diseases like lupus, sickle cell anemia, and cerebral palsy.

How is it diagnosed?

Most patients with Kienbock’s disease initially present with wrist pain. There is usually tenderness directly over the lunate bone, decreased motion or stiffness of the wrist, and there can be swelling. The diagnosis of Kienbock’s disease can often be made by history, physical examination, and plain x-rays. In early stages the x-rays may be normal and special studies are needed to confirm the diagnosis. Probably the most reliable special study to assess the blood supply of the lunate is Magnetic Resonance Imaging, or MRI . CT scanning, specialized CT scanning, and bone scan may also be used. Patients often have the condition for months or even years before they seek treatment, and especially in its earlier stage it can be difficult to diagnose.

             

          

What is its course?

The progression of Kienbock’s disease varies but is usually slow over many years. There are 4 stages used to classify Kienbock’s disease. In stage 1, x-rays appear normal, but the lunate has lost its blood supply and is painful and may fracture. In stage 2 the bone hardens due to lack of blood supply and appears abnormally dense on X-ray. In stage 3 the bone collapses and fragments. In the final stage, stage 4, the lunate is collapsed and the bones around the lunate have developed degenerative changes and become arthritic. In the early stages there may be only pain and swelling, but as the disease progresses the mechanics of the wrist become altered, which puts abnormal stresses and wear on the joints within the wrist itself. One should be aware that not every case of Kienbock’s disease progresses through all stages to the severely deteriorated arthritic end-stage.

What are the treatment options?

Treatment options depend upon the severity and stage of the disease. In very early stages, the treatment can be as simple as observation or immobilization. For more advanced stages, surgery is usually considered to try to reduce the forces on the lunate bone by lengthening, shortening, or fusing various bones in the forearm or wrist. Surgery can also be aimed at trying to restore blood supply to the lunate (revascularization), using a bone graft with a blood vessel attached to it. This is not an option in more advanced stages if the relationship of the bones has markedly deteriorated; complete wrist fusion may then be the preferred treatment. Hand therapy does not change the course of the disease; however, hand therapy can help to minimize the disability from the problem. Treatment is designed to relieve pain and restore function. Your hand surgeon will advise you of the best treatment options and explain the risks, benefits, and side-effects of various treatments for Kienbock’s disease

 What can I expect?

The results of Kienbock’s disease and its treatment vary considerably, depending on the severity of the involvement, and whether or not the disease progresses. The disease process and response to treatment can take several months. On occasion, several forms of treatment, and even multiple operations, might be necessary.