Erb's palsy is a form of brachial plexus palsy. It is named for one of the doctors who first described this condition, Wilhelm Erb.
The brachial plexus (BRAY-key-el PLEK-sis) is a network of nerves near the neck that give rise to all the nerves of the arm. These nerves provide movement and feeling to the arm, hand, and fingers. Palsy means weakness, and brachial plexus birth palsy causes arm weakness and loss of motion.
One or two of every 1,000 babies have this condition. It is often caused when an infant's neck is stretched to the side during a difficult delivery.
Most infants with brachial plexus birth palsy will recover both movement and feeling in the affected arm. Parents must be watchful and active participants in the treatment process to make sure their child recovers maximum function in the affected arm.
The brachial plexus is formed as the nerves to the arm, hand, and fingers pass from the spinal cord, between the bones of the neck (vertebrae) and go into the arm. Along the side of neck, these nerves merge together. From there, they branch out to form a "highway system," or "plexus," of nerves.
This system of nerves then travels behind the collarbone (clavicle) and spreads out into the arm. The nerves that go to the shoulder lie higher in the neck than those that travel to the hand and fingers. Nerves that provide feeling to the hand and fingers lie lower in the neck and deep in the armpit.
In most cases of brachial plexus birth palsy, it is the upper nerves that are affected. This is known as Erb's palsy. The infant may not be able to move the shoulder, but may be able to move the fingers. If both the upper and lower nerves are stretched, the condition is usually more severe than just Erb's palsy. This is called a "global," or total, brachial plexus birth palsy.
In general, there are four types of nerve injuries. All can occur at the same time in the same infant. The symptoms of a nerve injury are the same (loss of feeling and partial or complete paralysis), regardless of the type of injury. It is the severity of the injury that affects both treatment decisions and the extent of recovery possible.
A stretch injury that "shocks," but does not tear the nerve is the most common type. This is called a neurapraxia (new-rah-PRAK-see-ah). Normally, these injuries heal on their own, usually within 3 months.
Neurapraxia can happen in adults, as well as infants. For example, when it happens to football players who are injured during play, it is called "burners and stingers."
A stretch injury that damages some of the nerve fibers may result in scar tissue. This scar tissue may press on the remaining healthy nerve. This condition is called a "neuroma." Some, but not total, recovery usually occurs.
A stretch injury that causes the nerve to be torn apart (ruptured) will not heal on its own. A rupture happens when the nerve itself is torn.
An avulsion happens when the nerve is torn from the spinal cord. Nerve ruptures and avulsions are the most serious types of nerve injury. It may be possible to repair a rupture by "splicing" a donor nerve graft from another nerve of the child. It is not possible to repair an avulsion from the spinal cord. In some cases, it may be possible to restore some function in the arm by using a nerve from another muscle as a donor.
Brachial plexus stretch injuries in newborns usually occur during a difficult delivery, such as with a large baby, a breech presentation, or a prolonged labor. It may also happen when a birth becomes complicated and the person assisting the delivery must deliver the baby quickly and exert some force to pull the baby from the birth canal. If one side of the baby's neck is stretched, the nerves may also be stretched, and injury may result.
- Weakness in one arm
- Loss of feeling in the arm
- Partial or total paralysis of the arm
A pediatrician is usually the one to make the diagnosis of a brachial plexus palsy injury, based on weakness of the arm and physical examination.
Your doctor may order an x-ray or other imaging study to learn whether there is any damage to the bones and joints of the neck and shoulder. He or she may also do some tests to learn whether any nerve signals are present in the muscle of the upper arm. These tests may include an electromyogram (EMG) or a nerve conduction study (NCS).
Because most newborns with brachial plexus birth palsy recover on their own, your doctor will re-examine your child frequently to see if the nerves are recovering. It may take up to 2 years for complete recovery.
Daily physical therapy is the main treatment method for Erb's palsy.
Because a baby cannot move the affected arm all alone, parents must take an active role in keeping the joints limber and the functioning muscles fit. Your doctor or a physical therapist will teach you how to do exercises with your baby to keep your baby's arm in good condition.
Daily physical therapy and range of motion exercises, done as often as possible during the day, begin when a baby is about 3 weeks old. The exercises will maintain the range of motion in the shoulder, elbow, wrist, and hand. This will prevent the joint from becoming permanently stiff, a condition called joint contracture.
If there is no change over the first 3 to 6 months, your doctor may suggest exploratory surgery on the nerves to improve the potential outcome. Nerve surgery will not restore normal function, and is usually not helpful for older infants. Because nerves recover very slowly, it may take several months, or even years, for nerves repaired at the neck to reach the muscles of the lower arm and hand.
Many children with brachial plexus injuries will continue to have some weakness in the shoulder, arm, or hand. There may be surgical procedures that can be performed at a later date that might improve function. Your doctor will discuss the various treatment options and make a specific recommendation based on your child's individual situation. Do not hesitate to ask questions. There is much that you can do to help ensure a good return of function.
In some children, the affected arm is noticeably smaller than the unaffected arm. This occurs because nerves do have an effect on growth. Although the affected arm will continue to grow as the child grows, it grows at a slower pace, and the size difference will become more noticeable as the child gets older.
Children are very adaptable. Be supportive and encouraging, and focus on all the things your child can do. This will help your child develop a healthy sense of self-esteem and compensate for any limitations in function.
The American Academy of Orthopaedic Surgeons
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