Birth trauma may cause peripheral nerve damage in the form of a brachial plexus injury, which occurs most often in large babies due to shoulder dystocia or breech delivery. Brachial plexus injury occurs in about 0.5-2 per 1,000 live births in the United States, with Erb’s palsy being the most common (in about 10% of the cases of brachial plexus injury, the entire brachial plexus is involved).
The brachial plexus is the nerve bundles located on each side of the neck from the fifth through the eighth cervical nerves (C5 through C8) and the first thoracic nerve (T1) that run from nerve roots on each side of the upper spinal cord to regions underneath the collar bone where they branch out as the major nerves of the shoulders, arms, wrists, and hands. Injury to the brachial plexus may thus affect the shoulder, arm, wrist, and/or hand of the affected side.
There are four types of brachial plexus injury: a stretch, praxis, or traction injury (where the nerve has been overstretched but not torn), which is the most common type of brachial plexus injury in newborns; a rupture, involving a separation within a nerve; a neuroma, involving scar tissue forming around a nerve injury; and, an avulsion, which is the detachment of a nerve from the spinal cord and is the most severe form of brachial plexus injury.
Brachial plexus injury may be associated with fractured clavicle (10% of the cases), fractured humerus (10% of the cases), subluxation of the cervical spine (5% of the cases), cervical cord injury ( 5% to 10% of the cases), and/or facial palsy (10% to 20% of the cases).
Shoulder dystocia increases the risk of obstetrical brachial plexus palsy by 100-fold, with the reported incidence of obstetrical brachial plexus palsy after shoulder dystocia ranging between 4% and 40%, according to one study.
Another study found that there has been a four-fold rise in the incidence of shoulder dystocia in the United States since the mid-twentieth century, which may be related to a trend in the United States since the 1980s toward the active management of the birthing process instead of a more conservative approach (the study found no comparable increase in most of the other eleven countries studied).
Erb’s palsy involves C5-C6 and is associated with lack of shoulder movement. While grasp reflex is usually present, moro, biceps, and radial reflexes are absent on the affected side. The affected extremity lies internally rotated, prone, and adducted. Five percent of those with Erb’s palsy also have ipsilateral phrenic nerve paresis.
Klumpke’s paralysis involves C7-C8, T1 and is rare. Klumpke’s paralysis is associated with the absence of grasp reflex and weakness of the intrinsic muscles of the hand. Horner syndrome is present if cervical sympathetic fibers of the first thoracic spinal nerve are involved (Horner syndrome is the disruption of a nerve pathway from the brain to the face and eye on one side of the body, which typically results in decreased pupil size, a drooping eyelid, and decreased sweating on the affected side of the face).
Prognosis For Brachial Plexus Injury
One study found that 88% of brachial plexus injury resolved within the first four months of life, 92% resolved within one year, and 93% resolved within four years. Another study of 38 patients with total plexus palsy and 28 patients with upper plexus involvement found that 92% of those patients spontaneously recovered.
For those who do not fully recover from brachial plexus injury, the long-term effects may include muscle atrophy, joint contractures, bony deformities, impaired growth of the limb, weakness of the shoulder girdle, and/or Erb engram flexion of the elbow accompanied by adduction of the shoulder.
If your child suffered a brachial plexus injury during birth that has not fully resolved, you should promptly find a local medical malpractice lawyer (birth injury lawyer) in your U.S. state who may investigate your brachial plexus injury claim for you and represent you and your child in a brachial plexus injury case, if appropriate.
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