The brachial plexus is a bundle of nerves that exits the spinal cord at the level of the neck. It travels under the collarbone, passes through the axilla (arm pit), and then separates into the major nerves that supply motor (movement) and sensory (touch) function to the upper extremity. The brachial plexus can be injured during childbirth when a large baby travels down a small birth passage, and the baby's shoulder gets stuck on mom's pubic bone. This causes the shoulder to be stretched away from the head. In the process, the nerves of the brachial plexus may be stretched, torn, or avulsed (pulled out of the spinal cord). This results in impaired motor and sensory function of the affected arm.
Detailed repeated clinical examination and history is the primary means of diagnosing and classifying brachial plexus injuries. We typically have our patients start with a therapist at 4-6 weeks after birth to begin stretches and evaluate those that do not recover function within the first 2 months. Patients are then followed with a team evaluated every 3 months until one year of age. Most children are followed annually after this to address issues with joint stiffness, functional concerns, and body image concerns that can arise as patients get older.
Less frequently, for more severe injuries that do not show recovery in the first few months, plain X-rays, ultrasound, sedated MRI, or sedated EMG and electro diagnostic tests can be useful to further clarify the anatomy of the injury for patients that may require surgery.
The treatment of brachial plexus palsies depend on the severity of the injury and the level of the spinal cord roots involved. Typically less severe injuries involve mainly the upper roots (C5 and C6) and severe injuries involve all roots (C5, C6, C7, C8, and T1). The Narakas classification system is a more detailed system that is often used by clinicians to discuss severity of the injury.
Mild injuries (Neuropraxia) may spontaneously recover with the help of stretching and range of motion to keep the affected muscles balanced.
Moderate injuries that involve more severe scarring of the affected nerves (partial ruptures and more severe neuromas) may need interventions such as botulinum toxin injections and stretching under anesthesia. During infant and toddler years, muscles releases and tendon transfers when children are between four and six, and sometimes nerve transfers to strengthen weak muscles are needed.
More severe cases, which involve nerve avulsions or ruptures, may require surgery to explore the brachial plexus, release surrounding scar, remove any scar preventing nerve regrowth, place nerve grafts obtained from the legs, and transfer of nearby nerves. The initial surgery for severe brachial plexus injuries are long. The usual timing for surgery is between 4-9 months of age, depending on the severity of injury. The recovery of the function of the affected arm is a slow process that happens over 1 to 3 years.
For moderate and severe brachial plexus palsies, the affected limb may have lifelong impact, such as weakness, limb length and circumference differences, joint stiffness, muscle imbalance and joint contractures.
There are several types of surgeries that may need to be done as children get older. These include:
The outcomes are dependent on the severity of the injury and the timing of interventions. Stretched nerves often return to normal function with no intervention at all. Torn and avulsed nerves represent a more serious injury, but microsurgery techniques and physical/occupational therapy return more patients to near-normal function than ever before.