Definition and Diagnosis
During childbirth, after the baby's head is delivered, the shoulder may get stuck. This is unpredictable and is called a shoulder dystocia. The priority in this situation is to delivery the baby as quick as possible so that oxygen is not cut off. Although the true cause is uncertain and controversial, with continued pushing by the mother, or perhaps with pulling by the person delivering the baby, the brachial plexus of nerves between the spine and the shoulder (which control shoulder, arm, and hand movement) can be stretched and damaged. Damage to these nerves causes limb paralysis, which may be permanent.
If the stretch injury to these nerves is severe, they may even be torn apart, which may prevent spontaneous recovery. Birth brachial plexus palsy occurs in about 1-2/1000 births. Risk factors include diabetes or excessive weight gain in the mother, and a large baby. Examining the baby after delivery confirms this diagnosis. X-rays of the shoulder are important to exclude fractures and dislocations. A pediatric neurologist periodically examines your child as they recover.
Treatment Options
Physical therapy performed by the mother at diaper changes maintains arm range of motion and promotes recovery. Fortunately, most babies recover in a number of months. If the baby is not able to lift the hand to his/her mouth by six months of age, then surgery to repair the brachial plexus may be helpful. If this looks to be the situation, a high resolution MRI of the cervical spine is performed to exclude nerve avulsion from the spinal cord, along with electrical testing under sedation. These tests help determine if surgery is necessary, as well as what type of surgery to perform.
Besides surgery, the only other option is continued physical therapy, which is chosen by some parents. Some children who spontaneously recover good strength in their arm without surgery nevertheless continue to have trouble rotating their arm outward (like a tennis swing). These children may benefit from a much simpler surgical procedure where a single nerve transfer (see technologies and techniques available section) is performed.
MRI of the cervical spine in a newborn revealing a fluid collection that indicates rootlet avulsion from the spinal cord (asterisk)
Surgery
If indicated, surgery is performed under general anesthesia and takes several hours. A pediatric anesthesiologist provides anesthesia. The brachial plexus of nerves is exposed via an incision on the side of the neck above the clavicle. Damaged nerves are exposed and examined both with a microscope and intraoperative electrical testing.
Nerves are repaired with a variety of techniques (see technologies and techniques available section), including scar removal, nerve grafting, and nerve transfers. If nerve grafting is performed, the sural nerve is removed from the calf via an incision behind the lower leg. The sural nerve is minor sensory nerve. Therefore paralysis from removing this nerve does not occur. The baby wakes in the operating room and the family may visit in the recovery room shortly thereafter. By repairing the brachial plexus, these nerves now have the chance to regenerate. This regeneration takes 3-9 months to create muscle contraction. Therefore, immediately after surgery the child's paralysis is unchanged. Furthermore, even if surgery goes perfectly well, it unfortunately is not guaranteed to work.
A "success" is considered movement against gravity and some resistance. There is an approximate 75% chance of success for each nerve repaired. The surgeon will provide a better estimate of success following the operation. The reason for surgical failures is uncertain, but this partly depends on the nerve repaired, type of repair, and timing of surgery. Alternatively, for a simple nerve transfer to reanimate external rotation of the arm, surgery takes about 90 minutes and requires a small incision above the clavicle.
Exposure of the brachial plexus above the clavicle. This child had a neuroma (stretch injury) of the upper trunk causing shoulder and arm weakness.
Complications
Risks of birth palsy surgery include infection, additional paralysis, diaphragm paralysis, fluid on the lung, artery damage, and reactions to anesthesia. All of these risks are quite rare, but do occur. Before any operation, the surgeon will speak to you at length about each on of these risks. If only a nerve transfer is performed, then these risks are much reduced. Blood loss is usually minimal, therefore, blood donation by the parents is not recommended.
Recovery
Children spend a few days in the hospital for observation after surgery. Since in adults this procedure is not very painful, it likely the same for children, nevertheless, any signs of pain are treated with medication. The operated arm is gently immobilized for one to two weeks after surgery. All sutures are absorbable under the skin, so they do not need to be removed. Physical therapy is re-started about two weeks after surgery. Because surgery was used to repair the damaged nerves, they now have the opportunity to regenerate. As mentioned, this process takes 3-9 months to create muscle contraction. A more complete recovery may take even longer.
Further Reading
