What is the brachial plexus?
The brachial plexus is a network of nerves which run from the cervical spinal cord to the muscles of the upper limb.
What is brachial plexus birth palsy (BPBP)?
Brachial plexus birth palsy refers to an injury to these nerves sustained during childbirth. The nerves of the brachial plexus may be stretched, compressed, or torn. This may result in loss of muscle function and subsequent paralysis of the upper limb. Injuries may affect all or only a part of the brachial plexus, resulting in varying degrees of upper extremity involvement. Injuries to the upper brachial plexus (C5, C6) affect muscles of the shoulder and elbow, while injuries to the lower brachial plexus (C7, C8, and T1) can affect muscles of the forearm and hand.
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What are the types of brachial plexus birth palsy?
Brachial plexus birth palsies are often separated into different categories, depending upon the type of nerve injury and the pattern of nerves involved.
There are four different types of nerve injuries that may occur:
- The nerve roots are torn from the spinal cord – the injury occurs at the spinal cord.
- This is a less common form (roughly 10 to 20 percent of brachial plexus cases).
- It cannot be surgically repaired directly – damaged tissue must be surgically replaced (nerve transfers).
- It can injure the nerve to the diaphragm, causing difficulty breathing.
- A droopy eyelid on the affected side may indicate a more severe injury (Horner's syndrome).
- The nerve is torn but not where it attaches to the spine – the injury occurs outside the spinal cord.
- It's a common form.
- It may require surgical repair.
- The nerve has been stretched but not torn – the injury occurs inside the spinal cord.
- It's the most common form
- Affected nerve(s) may recover on their own – usually within three months of the baby's life.
- The nerve has tried to heal, but scar tissue has formed and presses against the injured nerve or interferes with nerve function.
- It may require surgical treatment with nerve reconstruction and/or secondary tendon transfers.
Terms used to describe different patterns of injury:
C5-C6-C7 (formerly called Erb's palsy)
- This represents roughly 60 to 70 percent of brachial plexus birth palsy injuries.
- It involves the upper portion (C5, C6, and sometimes C7) of the brachial plexus.
- A child typically has weakness involving the muscles of the shoulder and biceps.
- Home physical therapy begins when a baby is 3-weeks old to prevent stiffness, atrophy and shoulder dislocation.
C5-T1 (total plexus involvement)
- This represents roughly 20 to 30 percent of brachial plexus birth palsy injuries.
- This represents roughly 20 to 30 percent of injuries.
- It is usually associated with an avulsion (a tear of the spinal cord).
- The sympathetic chain of nerves has been injured, usually in the T2 to T4 region.
- The child may have ptosis (drooping eyelid) miosis (smaller pupil of the eye), and anhydrosis (diminished sweat production in part of the face.
- The child may have amore severe injury of the brachial plexus.
- This almost never occurs in babies or children.
- It involves the lower roots (C8, T1) of the brachial plexus.
- It typically affects the muscles of the hand.
How common is brachial plexus birth palsy?
Brachial plexus birth palsies occur in approximately 1-3 out of every 1,000 live births. Risk factors for the development of brachial plexus birth palsy include: large gestational size, breech presentation, prolonged or difficult labor, vacuum- or forceps-assisted delivery, twin or multiple pregnancy, and a history of a prior delivery resulting in brachial plexus birth palsy.