Introduction:
Damage to the brachial plexus’s nerve group, as in cases of difficult deliveries, causes poor sensation and muscle weakness in the newborn’s shoulder, arms, and hands. This injury is called neonatal brachial plexus palsy (NBPP), brachial plexus birth palsy, or Erb’s palsy. About one to two in every 1000 babies are affected by this condition.
Where Is the Brachial Plexus Situated?
The brachial plexus is formed as the nerves from the spinal cord pass between the bones of the neck (called vertebrae) and arms and travel to the arms, hands, and fingers. They combine on the side of the neck, almost near the shoulder, from where they branch out, creating a ‘plexus’ or a ‘network’. These groups of nerves travel behind the collarbone, called the clavicle, and supply the arms. Nerves supplying the hands and fingers are situated at a lower level in the neck, deep in the armpit. Nerves supplying the shoulder are situated at a higher level in the neck.
How Is Brachial Plexus Nerve Injury Caused?
The following are the reasons for brachial plexus birth injury:
-
Long durations of labor.
-
Increased weight of the baby.
-
Breech position (position of the baby such that its feet or buttocks are positioned near the vagina).
-
Compression of the brachial plexus nerves when the baby is in the womb.
-
Complicated delivery.
-
When the baby’s shoulder or neck is stretched while pulling out.
-
Obese mother.
-
When the baby’s shoulder is fixed or caught in the mother’s hip bone (pubic bone) after the head comes out. This condition is called shoulder dystocia.
-
More than one baby is delivered, like twins, triplets, or multiple deliveries.
-
Use of vacuum or forceps during delivery.
-
Previous history of delivery with brachial plexus injury.
When the brachial plexus nerves get stretched during the above conditions, the increased force causes nerve tears. Sometimes, the nerve roots of the brachial plexus emerging from the spinal cord can also be damaged. This results in decreased sensation and weak muscular movements.
What Are the Types of Neonatal Brachial Plexus Birth Palsy (NBPP)?
Based on the severity of arm paralysis, neonatal brachial plexus birth palsy (NBPP) can be classified as:
-
Duchenne-Erb or Erb-Duchenne Paralysis: Only the upper arm is affected in this condition.
-
Klumpke Paralysis: The klumpke paralysis is a rare and affects the lower arm.
What Are the Different Types of Nerve Injuries?
Brachial plexus birth injury is based on the type of nerve injury. These nerve injuries include:
-
Neuropraxia (Nerve Stretch): This is a common condition that occurs on the spinal cord's exterior part. It heals on its own within three months after delivery. The nerves are just stretched but not torn.
-
Neuroma: Some but not all the nerves are damaged due to stretching. Scar tissue is formed, which compresses the healthy nerves, but only some nerves recover.
-
Rupture: As the name suggests, the nerves are torn on the exterior of the spinal cord as a consequence of stretching. Self-healing the nerves is impossible; therefore, surgery may be required.
-
Avulsion: The nerves are torn from the spinal cord, which is a serious nerve injury. Surgery is difficult and involves nerve transfer from another part of the child's body. Horner's Syndrome is characterized by damage to the nerve tract on one side, resulting in eyelids drooping. This condition is associated with avulsion.
-
Total Plexus Involvement: All the nerves of the brachial plexus may be involved and represents 20 to 30 percent of brachial plexus injuries. The child will be unable to move their shoulder, arm, or hand.
What Are the Signs and Symptoms of Brachial Plexus Birth Injury?
The signs and symptoms include:
-
Weak hold or grip.
-
Numbness.
-
Awkward position of the arm, such as arms bent towards the body or limping.
-
Partial or complete loss of movement in the shoulder or arm.
-
Absence of Moro reflex or startle response (as a response to the sound, the baby throws the head backward, opens its arms and legs, and later moves them back in).
The baby usually does not experience any pain. However, if there is an accompanying fracture, the babies experience mild pain, but the fracture resolves within ten days.
How to Diagnose Brachial Plexus Birth Injury?
The doctor will physically examine the child for the above signs and symptoms. If the injury is confirmed, the doctor will proceed by taking X-rays, MRI (Magnetic resonance imaging), carrying out a nerve conduction study (NCS), and an electromyogram (EMG) to evaluate nerve and muscle function. The collar bone (clavicle) will be examined to find if there are any fractures.
What Is the Treatment for Brachial Plexus Birth Injury?
Various treatment modalities include:
-
Observation: Usually, the injury resolves in 3 to 12 months; however, frequent observation during this period is necessary to note the progress.
-
Physical or Occupational Therapy: Physical therapists (experts who focus on improving the body movements and function) and occupational therapists (experts who enable the patients to carry out day-to-day activities) assist the baby through exercises called the range of motion exercises or ROM exercises, which enables the movement of arms to prevent stiffness (joint contracture) and to tighten. Parents at home can follow the same.
If the injury does not heal within nine months of age, then a group of specialists, namely neurosurgeons (experts in surgery of the nervous system), neurologists (experts in treating diseases of the brain and nervous system), pediatric orthopedists (experts who treat joints, ligaments, and bones in children), brachial plexus specialist, physical and occupational therapists work in unison to proceed with the treatment.
Various modes of surgery include:
-
Nerve Grafts: This is done by taking a nerve from the back of the foot or rib and replacing it with the damaged nerve. Nerve grafts and nerve transfers are successful in infants between three to nine months and are not advised in infants beyond one year.
-
Nerve Transfer: This is done by transferring a nerve to the injured area from a muscle. Nerves take time to repair. Hence physical or occupational therapists must rehabilitate the baby after the surgery to enable normal movement.
-
Muscle Transfer: A muscle is commonly taken from the child’s thigh and is used to replace the paralyzed muscle of the arm.
-
Tendon Transfer: The end of the muscle attached to the bone is called the tendon. This process is carried out in children beyond one year of age by removing a normal functioning tendon from its attachment area and reattaching it in the shoulder area to enhance function.
-
Osteotomy: This is a procedure in which bones are cut and reattached in the desired area to improve the position of the hand and the arm to enhance their function.
-
Release of Joint Contractures: The soft tissues, which are thick and present around the shoulders and elbow joints, are relieved to improve movement.
What Are the Complications of Brachial Plexus Birth Injury?
The brachial plexus injury can cause the following complications:
-
Stiffness, abnormal contractions, and tightening of muscles can be permanent.
-
Complete or partial nerve damage can be permanent and lead to arm paralysis or a weak arm.
Conclusion:
The injury caused by brachial plexus birth injury resolves within nine months to a year after delivery. Usually, surgery is not needed in most cases. However, early diagnosis and treatment can ensure quick healing and a positive response to surgery. It may take some time for the nerves to improve their function. The healing period requires assistance from physical and occupational therapists to build strength, range of motion, and control of movements.
