Erb's palsy refers to the most common form of brachial plexus injury. "Brachial" refers to the arm, and "plexus" refers to a network of nerves. The brachial plexus is a network of nerves which transmits signals from the cervical spinal cord to the shoulder, arm and hand. Damage to the nerves of the brachial plexus can cause partial or total paralysis of muscles in the shoulder, arm, or hand.
Most brachial plexus injuries occur at birth. Approximately one or two babies out of every 1,000 born are affected. Nearly 90 percent of brachial plexus injuries resolve during the first year of life without the need for treatment. The remaining 10 percent of children require exercise, therapy, and, in the most severe cases, surgery. Even with the best treatment currently available, the most severely injured children will have substantial, lifelong functional limitations with regard to use of the affected arm and/or hand.
Anatomy of the brachial plexus
The brachial plexus is comprised of five spinal nerve roots that exit the spinal cord in the neck. These roots extend through the axilla (arm pit) behind the clavicle (collar bone), and then branch into nerves that enable movement (motor branches) and sensation (sensory branches) of the shoulder, arm, and hand.
The upper trunk of the brachial plexus consists of the C5-6 nerve roots, which exit the neck at the levels of the 5th and 6th cervical vertebrae, respectively. The middle trunk consists of the C7 nerve root, which exits the neck above the 7th cervical vertebrae. The lower trunk consists of the C8 and T1 nerve roots, which exit below the 7th cervical and 1st thoracic vertebrae, respectively. Erb's palsy refers to injuries of the upper brachial plexus, affecting muscles around the shoulder and elbow, and Klumpke's palsy refers to injuries of the lower plexus (C7-8 and T1), which affect muscles of the forearm and hand.
Erb's palsy comprise approximately 60 percent, Klumpke's about 5 percent, and mixed (upper and lower trunk involvement) perhaps 35 percent of all brachial plexus injuries.
Mechanism of injury
The most common mechanism of injury to the brachial plexus during birth is traction of the head and neck in a direction away from the site of injury. This results in a stretching of the affected nerve roots. Depending upon the degree of stretching, the resulting injury may be a praxis (stretch injury without tearing), rupture (partial tear), avulsion (complete tear off the spinal cord) of the affected nerve roots, or neuroma (in which scar tissue grows around an injured nerve which has tried to heal itself, and interferes with the nerve sending signals to the muscles).
Treatment of brachial plexus injuries
There are various types of surgical and non-surgical treatment available for children with brachial plexus injuries. The treatment required for any particular child will depend upon the nerve roots injured, and the severity.
Management of brachial plexus injuries must start with an accurate diagnosis, based upon careful physical examination during the newborn period or as soon as is practicable, along with any imaging studies, such as magnetic resonance imaging (MRI), CT scanning, or electrodiagnostic studies such as electromyography (EMG) or nerve conduction studies which may be necessary. A pediatric neurosurgeon and/or microsurgeon should perform an initial evaluation within six to eight weeks after birth, in order to determine whether the child may be an appropriate candidate for nerve reconstruction surgery, which generally must be performed within the first year of life.
Physical therapy and/or occupational therapy should be started as soon as possible, along with instructions to the parents on how to perform range of motion exercises with their child at home.
Children who might not benefit from nerve reconstruction surgery may nevertheless be helped by another type of surgery involving muscle transfers, generally performed as early as age two and as late as age eight, which may significantly increase function, even though nothing can be done to repair the damaged nerves.
For more information regarding treatment options, be sure to visit the Resources section below.
Can brachial plexus injuries be prevented?
Many cases of brachial plexus injury that occur during childbirth are preventable. Since there are known risk factors which increase the possibility that a baby will be born with a brachial plexus injury, the key to prevention is identification and management of risk factors.
Most brachial plexus injuries occur during deliveries in which shoulder dystocia is encountered. Shoulder dystocia is a condition in which one of the baby's shoulders becomes stuck under the mother's pelvic bone during the birth process. It is considered an obstetrical emergency, because a rapid, skillful response is required to avoid serious injury, or, in some cases, the death of the baby. If managed with the proper manual maneuvers, nearly all cases of shoulder dystocia can be resolved without any injury to the baby.
Although shoulder dystocia cannot be predicted in advance with certainty, the presence of a large (nine pounds or more) baby significantly increases the likelihood that shoulder dystocia will develop during labor. Babies with mothers who are diabetic are significantly more likely to approach or exceed nine pounds, and therefore special attention must be paid to the possibility of developing shoulder dystocia during delivery of babies of diabetic mothers.
Medical negligence may cause Erb's palsy or other brachial plexus injuries under the following circumstances:
The web sites listed below contain information which may be useful to people interested in learning more about Erb's palsy, Klumpke's palsy, or brachial plexus injuries, including resources which are available to help children with brachial plexus injuries and their families. Kenneth M. Sigelman & Associates is not affiliated with any of these other sites, and cannot be responsible for content. Please feel free to contact us if you aware of other helpful links to include in this site.
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