What is the brachial plexus?
The brachial plexus is a network of nerves that originate in the neck region and branch off to form most of the other nerves that control movement and sensation in the upper limbs, including the shoulder, arm, forearm, and hand. The radial, median, and ulnar nerves originate in the brachial plexus.
Causes of a brachial plexus injury
Brachial plexus injury (BPI) is an umbrella term for a variety of conditions that may impair function of the brachial plexus nerve network. The majority of pediatric and adult brachial plexus injuries are caused by trauma. The most common inciting events may include:
- High-speed vehicular accidents, especially motorcycle accidents
- Blunt trauma
- Stab or gunshot wounds
- Inflammatory processes (brachial plexitis)
- Compression (for example caused by a growing tumor)
A brachial plexus injury occurring during birth is called birth related brachial plexus palsy or obstetric brachial plexus palsy.
What is obstetric brachial plexus palsy?
Obstetric brachial plexus palsy occurs in less than 1% of live births. It is most common when there is difficulty delivering the baby's shoulder. During delivery, the baby's shoulder may become impacted on the mother’s pubic bone causing the brachial plexus nerves to stretch or tear (shoulder dystocia). The prognosis for recovery depends on the pattern, complexity, and severity of injury. Erb's Palsy refers to an injury of the upper brachial plexus nerves leading to loss of motion around the shoulder and ability to flex the elbow. Klumpke's palsy refers to an injury of the lower brachial plexus leading to loss of motion in the wrist and hand.
Types of brachial plexus injuries
Brachial plexus injuries are categorized according to the type of trauma experienced by the nerve. The following are the types of brachial plexus injuries:
- Avulsion – this means the nerve has been pulled out from the spinal cord and has no chance to recover.
- Rupture – this means the nerve has been stretched and at least partially torn, but not at the spinal cord.
- Neurapraxia – this means the nerve has been gently stretched or compressed but is still attached (not torn) and has excellent prognosis for rapid recovery
- Axonotemesis – this means the axons (equivalents of the copper filaments in an electric cable) have been severed. The prognosis is moderate.
- Neurotemesis – this means the entire nerve has been divided. The prognosis is very poor.
- Neuroma – this refers to a type of tumor that grows from a tangle of divided axons (nerve endings), which fail to regenerate. The prognosis will depend on what percentage of axons do regenerate.
Symptoms of a brachial plexus injury
BPI may result in some of the following symptoms:
- Loss of sensation
- Muscle weakness
- Paralysis of some or all of the muscles of the shoulder and upper limb
Some patients may experience avulsion pain (a burning, crushing type of pain) in the distribution of the injured nerves.
Diagnosis of brachial plexus injury
Due to the complex spectrum of brachial plexus injuries, a detailed and comprehensive understanding of the exact nature of injury in each patient is required for proper management.
Multiple modalities are utilized to diagnose a brachial plexus injury including:
- History taking and clinical examination
- Electrodiagnostic studies (EMG, NCV, SNAP, SSEP)
- Imaging studies (CT, MRI)
Some of these evaluations may need to be repeated on a regular basis to track the progression of recovery of function. Used in combination, these modalities provide valuable insights into the elements of the brachial plexus that have been injured including information about the severity of the injury and prognosis.
Treatment for a brachial plexus injury
Due to the broad spectrum of brachial plexus injuries, it is difficult to estimate the rate of spontaneous recovery. The potential for spontaneous recovery depends on the type and severity of injury. Therefore, prognosis must be assessed for each patient individually based on the type and severity of their injury, and the progression of any spontaneous recovery that may be occurring.
Nonsurgical treatment options for brachial plexus injuries
Depending on the degree of severity, some nerve injuries are able to heal on their own. If this is not a viable option for a particular patient, a surgical option may be recommended by the physician. Physical rehabilitation therapy is always part of the recovery process for a brachial plexus injury.
Surgical treatment options for brachial plexus injuries
The degree of functional impairment and potential for recovery depend on the mechanism, type, complexity of the brachial plexus injury, and time from injury. The most important decision your surgeons will make is determining if and when surgical intervention should occur. Learn more about surgery for a brachial plexus injury.
Dr Allan Belzberg is a world-renowned neurosurgeon in the treatment of peripheral nerve injuries. He treats on average 500 nerve injuries every year and has published research publications focusing on improving surgical repairs of nerve injuries and discovering new treatment options. Catch up on the latest research on nerve injuries.