Erb’s palsy is a nerve injury to the brachial plaxis (the nerves surrounding the shoulder), which causes weakness or paralysis of the upper arm and sometimes affects rotation of the lower arm. Erb’s palsy is almost always a result of shoulder dystocia. It should not be confused with other injuries to the brachial plexus such as Klumpke’s palsy, which affects the hand, or cerebral palsy, which is caused by injury or damage to the brain.
Symptoms and Diagnosis
Because Erb’s palsy occurs at birth, symptoms are often present immediately. A classic indication is when the affected arm hangs to one side and is rotated inward, and the forearm is extended and rotated outward. Loss of sensation and muscle atrophy is also common. The injury often stunts growth of the arm, hand, and/or fingers, resulting in a smaller-than-average limb.
When the brachia praxis nerves are simply injured or stretched during birth, a complete recovery over time is sometimes possible; however, when the nerves are separated or torn from the spinal cord, there will be permanent damage. An MRI or EMG can confirm a suspected case of Erb’s palsy.
Risk Factors and Prevention
Because Erb’s palsy is usually caused by shoulder dystocia, the same risk factors apply to both birth injuries. Some common risk factors for shoulder dystocia are:
- A prior birth in which the infant experienced shoulder dystocia, even if it did not result in Erb’s Palsy
- Larger babies, especially those born to mothers with diabetes or gestational diabetes
- Babies with above-average birth weight
- Smaller mothers, particularly those with smaller pelvises
- Labors in which the second stage of labor (when the mother starts to push) lasts longer than two hours
- Breech position births
Shoulder dystocia, which can lead to Erb’s palsy, is preventable with proper prenatal care, a prepared and knowledgeable birth and delivery team, and timely intervention if symptoms are expressed.
There are three common types of treatment for Erb’s palsy:
- Nerve transplants—Usually from the opposite arm or limb, often performed on babies under nine months old
- Sub scapularis release—”Z” shape cut into sub scapularis muscle to provide stretch within arm
- Latissimus dorsi tendon transfer—Latissimus dorsi cut in half horizontally to “pull” part of muscle around and attach it to outside of biceps
A failure to properly evaluate the risk factors for Erb’s palsy and perform a timely C-section can result in a severe, lifelong injury.
Williams Obstetrics, 23rd Ed.
T. Russell – J. Tolliver, M.D.