What is Brachial Plexus Palsy?
Brachial Plexus Palsy in newborns is caused by injury to the nerve roots or nerves to the arm typically during the birthing process. About one to two in 1,000 full-term newborns suffer a Brachial Plexus Palsy. Some injuries can be due to traumas or accidents.
The most common case of injury is during childbirth when there is difficulty delivering the baby's shoulder, which causes over-stretching of the neck, leading to stretched or torn muscles in the neck and shoulder regions (the brachial plexus).
Any of several nerves can be involved in an injury to the brachial plexus, which is the network of nerves which stem from spinal cord rootlets in the neck between the vertebrae C4 and T1.
The brachial plexus is located just behind the collar bone and divides into the three main nerves which descend down to the muscles of the arm and hand. Smaller nerve branches reach out into the shoulder and the muscles which stabilize the shoulder blade.
- Stretched nerves cause temporary weakness of the arm
- Torn nerves may result in a neuroma, a lump of swollen tissue that results when nerves try to heal and reconnect
- Torn nerve roots that have disconnected from the spinal cord cause root avulsion, the most serve condition.
If nerves are stretched, it is likely that movement will return within a few months, and may be improved through physical therapy. If nerves were torn, especially at the root, there likely is nerve damage that may be treated surgically.
What are the Symptoms?
- Baby holds the arm turned in at the shoulder
- Elbow is straight, the wrist bent, and the hand fisted and turned backward
- Most babies can open their hand somewhat
- Most can straighten their wrist somewhat
- They cannot move their shoulder or bend their elbow
- The feeling in their hand and arm is usually normal
In severe cases or Complete Brachial Plexus Palsy
- The arm hangs limply by the baby’s side, with the hand open.
- There usually is little or no feeling in the arm and hand.
- The child also may have a droopy eyelid on the same side.
How is it Caused?
A brachial plexus injury occurs when the brachial plexus (the group of nerves that supply the arm and hand) is over-stretched, typically during a difficult vaginal delivery. Mild injuries (stretched nerves) will likely heal with time. Severe injuries may result in compromised motion, decreased sensation as well as atrophy.
What are the Risk Factor for this Injury?
- Excessive weight gain during pregnancy
- Diabetes, preexisting or gestational
- Abnormal position of baby (especially breech)
- Abnormal shape of the uterus
- Mid- or high-forceps delivery
- Large size and/or wide shoulders of baby
- Stiff neck – “wry neck” – which does not permit head to engage into the birth canal
How are Brachial Plexus Injuries and Palsies Diagnosed?
With mild injury to the nerves of the brachial plexus, a pediatrician will examine the child periodically to determine if damage is mild or severe. If a child is referred to a specialist, further diagnostic tests can pinpoint nerve damage.
When injury is detected, physical and occupational therapy will be instituted early and close clinical observation will determine if the child will need to undergo surgical restoration. If there is insufficient neurological improvement by 3 to 6 months, surgical correction may be the only possibility of regaining any strength or sensation in severely affected nerves.
Electrodiagnostic testing, including EMG and somatosensory response can confirm the diagnosis and indicate the degree of damage. If surgery is indicated, these tests will also be used during surgery to carefully select which nerves will be targeted for repair.
How are Brachial Plexus Injuries Treated?
Injured or torn nerves may regenerate if the protective sheath (myelin) around them is intact. Growth rate is about one inch per month. Once a child has been evaluated, a physical or occupational therapist and/or neurologist will develop a plan of treatment. If surgery is recommended, a neurosurgeon will also be part of the care team.
For mild injuries – stretched nerves:
If nerves were only stretched, a physical or occupational therapist can teach family or friends how to care for the baby to restore nerve and muscle function.Many babies recover completely with a regular exercise program:
- The child should be positioned so she/he does not lie on the arm
- The child’s arm, shoulder, wrist and hand should be gently exercised several times a day.
- Movement during exercise may cause pain, which should subside after two or three weeks of the exercise program
For more serious injuries:
Babies with brachial plexus injuries should be seen weekly or biweekly by a pediatric physical or occupational therapist beginning at two or three months of age.
A physical or occupational therapist may recommend the following:
Use of various splints as needed that will
- protect the arm
- extend the arm for proper muscle development
- straighten the fingers
- Therapeutic stretching to maintain the arm’s range of motion
- Use of pushing and pulling toys and activities to strengthen the arm
Surgery for Brachial Plexus Palsies
If there is little to no improvement through physical and occupational therapy by three months of age, a child should be reevaluated, and neurosurgery may be recommended. It is important to move forward with neurosurgery before the child reaches one year, to assure best outcomes.
Other surgeries related to improving functioning of tendons or muscles and even bones may be recommended for older infants (2-4 years old) depending on outcomes from therapy and neurosurgery.
If neuromas have developed (clumps of nerve tissue caused by nerves trying to heal and reconnect) a neurosurgeon may remove scarring along the nerve pathway, called (neurolysis) and graft the two ends of the nerve with a nerve taken from another location.
Children’s neurosurgery team uses the most sophisticated intra-operative monitoring techniques to assure best outcomes during reconstruction of delicate nerves and tissue. Intra-operative monitoring includes the use of EMG and somatosensory response to identify and test the nerves to be repaired.
After this surgery, the child will need to keep the arm and shoulder in a sling, so it remains immobile for several weeks.
Orthopaedic and Plastic Surgery
Since the introduction of early and effective therapy for newborns with brachial plexus injuries, surgery of tendons, muscles and bones may not be necessary, or may be done later in life. If nerves are repaired early in life, they can regenerate and other structures will not be compromised. If surgery is required, it may be recommended for older infants, aged four to six.
In some cases connective tissues between muscle and bone that have been compromised due to nerve damage can be repaired through a tendon transfer. The surgeon separates the tendon from its normal attachment and reattaches it in a different place. This can be helpful in improving shoulder and wrist motion as well as elbow position and hand grip.
Tendon transfers are generally performed when the child is older– at about 3-4 years old. Physical therapy may continue indefinitely after surgery.
In some cases, if function of the arm has been severely compromised, it is possible to realign the arm bone surgically by turning it and/or transferring muscles so the child can turn his or her shoulder. Severe elbow, wrist and hand constrictions can sometimes be treated with muscle and tendon releases.
Low current electrical stimulation can help strengthen weak muscles. Children must be old enough and intelligent enough to report discomfort and to cooperate with a physical therapist to use this approach. Outcomes indicate that electrical stimulation may be an important additional therapy.
What Can We Expect?
Some children make full recoveries from their injuries and grow up unaware of any problem. Even with these children it is important to encourage activities that require use of both arms so their limbs continue to strengthen evenly. Activities such as swimming and rowing will lead to better cosmetic appearance as well as function.
Nevertheless, other children will have various degrees of compromised function of their arms and hands. They can expect to participate fully in life with ongoing physical or occupational therapy. In some children, shoulders, arms or hands may be smaller or may not be fully flexible and may lead to greater fatigue of the involved limb.