The brachial plexus is the network of nerves that sends signals from your neck spine to your whole upper limb; shoulder, arm and hand. A brachial plexus injury occurs when these nerves are stretched, compressed, or in the most serious cases, ripped apart or torn away from the spinal cord.
Injury to the brachial plexus can occur in several ways.
- This is a common cause of severe brachial plexus injury. Common trauma includes motor vehicle accidents, motorcycle accidents, falls or bullet wounds.
- Contact sports. In contact sports, players get into collision with other players and their brachial plexus can get stretched. They can experience burners or stingers (electric shock or a burning sensation shooting down the arm) which can last for few minutes or days.
- Difficult births. Newborns can sustain brachial plexus injuries during problematic birth, such as a shoulder dystocia, a breech presentation or prolonged labor. If an infant’s shoulders get wedged within the birth canal, there is an increased risk of a brachial plexus palsy.
- Inflammation may cause damage to the brachial plexus. A rare condition known as Parsonage-Turner syndrome (brachial plexitis) causes brachial plexus inflammation with no apparent cause and results in paralysis of some muscles of the arm and numbness or pain.
- Noncancerous (benign) or cancerous tumors can grow in the brachial plexus or put pressure on the brachial plexus causing damage to the brachial plexus.
- Radiation treatment. Radiation treatment may cause late-onset damage to the brachial plexus.
Signs and symptoms of a brachial plexus injury can vary greatly, depending on the severity and location of the nerve injury.
Minor damage often occurs during contact sports, such as football or wrestling, when the brachial plexus nerves get stretched or compressed. These are called stingers or burners, and can produce a feeling like an electric shock or a burning sensation shooting down your arm and numbness and weakness in your arm. These symptoms usually last only a few seconds or minutes, but in some people may linger for days or longer.
More severe symptoms result from injuries that seriously injure or even tear or rupture the nerves. The most serious brachial plexus injury (avulsion) occurs when the nerve root is torn from the spinal cord. This commonly occurs following a fall from height or a road traffic accident. Signs and symptoms of more-severe injuries can include weakness or complete paralysis of muscles in your hand, arm or shoulder, lack feeling or numbness in your arm, including your shoulder and hand and severe pain over the upper extremities.
When to see a doctor
Brachial plexus injuries can cause permanent weakness or disability. Even if yours seems minor, you may need early assessment and constant monitoring of recovery. Early physical therapy limits muscle wasting and joint stiffness. Consult a hand surgeon if you have:
- Recurrent or constant burners and stingers
- Weakness in your hand or arm or complete paralysis
- Neck pain
It is important to be evaluated early. Surgical treatment is usually initiated within six months after the injury if patients show no sign of improvement spontaneously. Delays in treatment may compromise outcomes of nerve surgeries.
To make a diagnosis, your doctor will review your symptoms and conduct a physical examination.
Further imaging and test may be required to help diagnose the extent and severity of a brachial plexus injury,
- Electromyography (EMG). This test evaluates the electrical activity of your muscles when they contract and when they’re at rest and thus determine whether the muscle is denervated (not receiving signal from nerve) or getting reinnervation (recovering)
- Nerve conduction studies. These tests may be performed with the EMG, They measure the speed of conduction in your nerve and provide information about how well the nerve is functioning.
- Magnetic resonance imaging (MRI). This imaging test can often show the extent of the damage to the brachial plexus and also help to assess the status of blood supply to the limb.
- Computerized tomography (CT) myelography. This is an alternative to MRI. In CT myelography, a contrast material is injected during a spinal tap, to produce a detailed picture of your spinal cord and nerve roots.
- If blood vessels supplying your arm might be injured, an arteriogram will be performed. A contrast material is injected into an artery or vein and imaging is performed to check the patency and continuity of your blood vessels.
Treatment of brachial plexus injury depends on several factors including the severity of the injury, the type of injury, the length of time since the injury and other co-existing conditions.
Nerves that have only been stretched may recover without further treatment. While waiting for recovery, you will need physical therapy to keep your joints and muscles working properly and to prevent stiff joints.
If you failed to recover spontaneously within the expected time, surgery is warranted. Surgery to repair brachial plexus nerves should generally occur within six months after the injury. If nerve surgery is performed later, the muscles may not recover their function completely.
There are various surgical techniques.
- The nerve healing process sometimes forms scar tissue that must be removed surgically to improve the nerve’s function (Neurolysis).
- Surgical repair of the nerves is often required for nerves that have significant surrounding scar tissue requiring excision or that have been cut or torn completely. Most of the time, during surgical repair, nerve grafting is required. In this procedure, the damaged part of the brachial plexus is removed and the resulting gap is bridged with sections of nerves harvested from other parts of your body, commonly from the leg.
- When the nerve root has been torn from the spinal cord, surgeons often take a less important functioning nerve and connect it to the damaged nerve.This is called nerve transfer or neurotisation. Surgeons may perform this technique at a level close to the targeted muscle in an effort to speed up recovery rather than doing a repair (nerve graft) farther from the muscle.
Sometimes surgeons may perform a combination of neurolysis, nerve grafting and nerve transfer.
After the repair, the muscle or sensation do not recover immediately. New nerve tissue needs to grow towards the paralysed muscle and sensory apparatus before muscle contraction and sensory restoration can recover. Nerve tissue grows slowly, about 1mm a day or an inch (2.5 centimeters) a month, so it can take more than a year to know the full benefit of surgery. During the recovery period, you must keep your joints flexible with exercises. Splints may be used to keep your hand and wrist from curling inward permanently.
Sometimes, patients come late for treatment when the nerve surgery will most likely result in poor outcome. Occasionally, the initial nerve surgery failed to restore any functional movements. In these scenario, secondary reconstruction can be carried out. Various options are available:
- Muscle or tendon transfer. Muscle or tendon transfer is a procedure in which your surgeon removes a less important functioning muscle or tendon and transfers it to the paralysed muscle or tendon to restore the weak or absent motion. Occasionally, the whole muscle and tendon is harvested from the thigh and transferred to the paralysed arm, and the surgeon will reconnect the nerves and blood vessels supplying the muscle.
- Fusion of flail joints. This option stabilizes the flail joints allowing better positioning, improving the function of other functioning but weak muscles and appearance of the hand. It is commonly performed for the wrist.
Pain from brachial plexus injuries can be very severe and debilitating. It has been described as severe crushing sensation or a constant burning pain. Narcotic medications and other pain-killers are often used initially, but may be changed as your recovery progresses to optimize pain relief.