The brachial plexus is a branching network of intersecting nerves that control movement and sensation in the shoulder, arm and hand. The brachial plexus originates from the spinal cord, emerging from the last 4 cervical nerves and the first thoracic nerve at the low neck level and passes the upper chest extending into the armpit.
Causes of Brachial Plexus Injury
Most traumatic brachial plexus injuries occur when the arm is vigorously pulled or stretched. Many events can produce an injury, including falls, motor vehicle collisions, knife and gunshot wounds, and most commonly high-speed motorcycle accidents.
Many brachial plexus injuries happen when the arm is pulled downward, while the head is pushed to the opposite side.
Different Types of Brachial Plexus Injury
Brachial plexus injuries differ significantly in severity, depending upon the type of damage and the amount of force placed on the plexus. The same patient can harm several nerves of the brachial plexus in varying severity.
- Avulsion (Neurotmesis). The avulsion is considered the most severe brachial plexus injury as it is defined by the complete disruption of both the nerve and the nerve sheath. Because of the severity of the injury, surgical therapy is the only option and the outcome is unpredictable.
- Rupture. A less severe, but still concerning, form of injury is defined by the nerve rupture, which is characterized by the partial or complete tear of the nerve, whilst maintaining the surrounding connective tissues. Surgical therapy might be needed to repair the damage.
- Stretch (Neuropraxia). The stretch of the nerves is considered the mildest form of brachial plexus injury. When the nerve is mildly stretched, it may temporary lose motor and/or sensory function. This type of injury usually heals by itself, or might require non-surgical therapy.
Symptoms of Brachial Plexus Injury
The symptoms vary depending on the type and location of the injury as well as from the mechanism of injury and forces involved in it. The most common symptoms of brachial plexus injury include weakness or heaviness, partial numbness or complete loss of sensation, loss of function (the patient can’t move the upper limb) and pain in the neck, shoulder and upper limb area, and sometimes diminished radial/brachial pulse due to vascular injury.
Diagnosis of Brachial Plexus Injury
The diagnosis is based on the clinical manifestations and the physical examination performed by the physician. Additional tests might be required: X-Rays, MRI, CT Scans, Electrophysiologic studies are all used to confirm the diagnosis as well as to determine the severity of injury and best course of treatment. Patients with brachial plexus injuries must be evaluated and treated within an appropriate timeframe to avoid permanent damage and loss of function. 9-12 Months after the injury took place, any residual symptoms are usually permanent.
Treatment of Brachial Plexus injury
- Nonsurgical Treatment
In the past, most of the brachial plexus injuries were treated conservatively (without surgery) and any residual deficit after 12-18 months would be deemed permanent. Nowadays, only mild injuries are treated non-surgically. Sometimes bracing is necessary. Physical therapy and electrical stimulation may improve the outcome. Lately, stem cell therapies are being investigated and preliminary studies show promising results.
- Surgical Treatment
Surgical treatment is typically recommended when examination and tests reveal a severe injury or when conservative approaches fail to improve the symptoms. The type of surgical intervention depends upon the clinical findings, type of injury, age of the patient and the timing between the injury and the surgery.
Among the options there are:
- Nerve repair, where the torn ends of the nerve get reattached
- Nerve graft, where a piece of nerve tissue from another part of the body is used to connect and repair the damaged parts.
- Nerve transfer, when the graft is not possible due to extensive damage to the existing nerve, a different nerve with redundant or less important role might be cut and connected to restore function in a more important region.
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