What is Brachial Plexus Injuries?
The first known record of a brachial plexus injury, which is damage to a group of nerves in your shoulder area, goes back to around 800 BC. This was mentioned in Homer’s ‘The Iliad,’ when a character named Hector hit Teucer over the shoulder with a rock, causing him to lose the ability to use his bow.
In simple terms, the brachial plexus is like a grouping of five nerve roots named C5 to T1. They start at the backside of your neck and stretch into the armpit, ending in five nerves known as musculocutaneous, axillary, radial, median, and ulnar. Sometimes, the C4 and T2 nerve roots also contribute to this grouping.
The structure of the brachial plexus can be visualized like a tree, with roots at the top going down to trunks, divisions, cords, and branches at the bottom. It’s more common for the root and trunk areas to be damaged than the division, cord, and branch parts.
What Causes Brachial Plexus Injuries?
The brachial plexus, a group of nerves that sends signals from your spine to your shoulder, arm, and hand, can be injured in a variety of ways. This includes severe injuries from childbirth, hard falls, blunt force hits, high-speed car crashes, penetrating injuries, forceful pulling, or compression injury.
Injuries to the upper part of the brachial plexus can happen when the head and neck are harshly pulled down away from the shoulder and body. Likewise, injuries to the lower part of the brachial plexus can occur when the arm is forcefully lifted above the head.
For patients with multiple injuries, like the polytrauma patient, brachial plexus injuries are quite rare. However, with these patients, doctors often need to focus on other more urgent blunt force injuries to the head, torso, limbs, and major blood vessels first. This can make it harder to identify and treat an injury to the brachial plexus early on.
Risk Factors and Frequency for Brachial Plexus Injuries
Brachial Plexus Injury (BPI) is often seen in males aged between 15 and 25. Most of these injuries occur due to traffic accidents, particularly involving motorcycles or bicycles. These injuries are often serious, impacting the supraclavicular plexus, which is a network of nerves in the neck and one or many roots of these nerves are often torn off in about 70% of cases. The lower plexus is also usually affected, leading to lasting pain in 70% of these cases.
Second to traffic accidents, gunshot wounds are the second most common cause of Brachial Plexus Injury resulting in nerve blockage. Having this kind of nerve damage can result in substantial disability and ongoing difficulties with everyday activities. This puts a great strain not just on the patients themselves, but also on their caregivers. This stress can lead to both mental health and financial issues.
- BPI usually affects males between the ages of 15 and 25.
- About 70% of these injuries are due to traffic accidents, and 70% of these accidents involve motorcycles or bicycles.
- Of these patients, 70% have multiple injuries.
- About 70% of these patients have an injury to the supraclavicular plexus – a network of nerves in the neck.
- 70% of these supraclavicular injuries also involve the tearing off of one or more nerve roots.
- Of the patients with nerve root tears, 70% also have damage to the lower plexus and 70% of them have chronic pain as a result.
- Gunshot wounds are the second most common cause of BPI.
- BPI can cause substantial disability and make everyday activities difficult.
- This condition also places a significant strain on both patients and caregivers, due to mental health and financial issues.
Signs and Symptoms of Brachial Plexus Injuries
If you think you might have a brachial plexus injury (BPI), which affects the nerves in your neck, shoulder, and chest, it’s crucial to give a detailed medical history to your doctor. This should include the specific event that caused the injury, any associated broken bones, and any other trauma to your neck, shoulder, and chest area. The doctor will then carefully inspect you for signs of injury. Large bruises and swelling can suggest a deep trauma with potential harm to your blood vessels. This can be confirmed by checking your radial, ulnar, and brachial pulses on your wrist and arm.
A comprehensive neurological exam is important to pinpoint the location of the injury. For example, paralysis of the muscles along the spine may indicate an injury at the spot where the nerves exit from the spinal cord in the neck. The doctor might also check for muscle activity in the latissimus dorsi (a large back muscle) and the pectoralis major (a big chest muscle), as these muscles are supplied by specific nerves. This can help the doctor determine whether the injury is closer to the spinal cord or farther away.
Testing for Brachial Plexus Injuries
When looking for injuries in areas like the neck, collarbone area, upper spine, first rib, and shoulder blade, doctors often use X-rays as their initial tool. Additional tests like MRI and CT scans can further detail the extent and nature of injury and help make predictions about the chances of recovery. MRI and CT scans are especially helpful in identifying a tear in the meningeal lining of the spinal cord due to nerve root tears. However, sometimes bleeding at the injury site might distort the test results. Hence, it’s often advised to wait for 3 to 4 weeks from the time of injury before having a CT scan, to allow this bleeding to be reabsorbed into the body. An MRI is a less invasive option that can also reveal useful details, such as inflammation and edema (swelling).
A test involving the recording of sensory nerve action potential (the response of sensory nerves when stimulated) can help differentiate between injuries that are before the nerve ganglion (preganglionic) and injuries that are beyond the nerve ganglion (postganglionic). If specific areas of the body lose sensation, but this test shows that sensory cells are still working, it indicates an injury before the nerve ganglion. Electromyography, a test that involves inserting a needle into muscles to assess their electrical activity, can also help differentiate between preganglionic and postganglionic injuries by directly stimulating muscles connected to the nerves affected by the injury. In this case, muscles in the back near the spine, shoulder blade, and upper chest muscles may be examined.
The doctor will also check for certain symptoms related to nerve injuries. For instance, injuries involving the nerves connected to the serratus anterior muscle (a muscle near the ribs) can cause noticeable protrusion of the shoulder blade. Injury to the nerve component that contributes to the phrenic nerve from the fifth cervical nerve (C5) can cause one side of the diaphragm -the muscle essential for breathing- to elevate, which can be seen on a chest X-ray.
Treatment Options for Brachial Plexus Injuries
The best timing for surgery to treat Brachial Plexus Injury (BPI), which is a type of nerve injury, is still being debated among medical professionals. Immediate surgery is often necessary if the injury is serious, such as an open wound, a suspected tearing or severance of a nerve, or an injury involving a foreign object or blood vessel damage. Nerve repair can be optimized if the brachial plexus, which is a network of nerves, has been cleanly severed. BPIs resulting from less severe injuries often have a better prognosis and can be treated without surgery, instead allowing the body to heal naturally.
During this healing process, the patient will need to be closely and regularly monitored through physical check-ups, imaging studies like scans, and tests to measure nerve activity. If there haven’t been sufficient improvements in nerve function after three to six months, delayed surgery might be considered.
However, there are cases when surgery is not advisable. For instance, if a patient is physically or mentally not fit for surgery, or if there are local wounds or infections that may hamper the operation. Surgery may also be more difficult and complicated due to swelling and scar tissue around the neck region. Other factors that may contribute to avoiding surgery depend on individual circumstances.
If a BPI injury is more than a year old, it typically does not benefit much from surgical repair, except in children who have a higher capacity for regeneration. Patients who do not demand much from their physical functions and those with permanent stiffness in their joints due to previous injury might not be good candidates for surgery since significant improvements would be challenging to achieve. Furthermore, patients who may not adhere to or tolerate rigorous physical therapy, which can last for several years, are likely to have worse outcomes.
What else can Brachial Plexus Injuries be?
Thoracic outlet syndrome refers to a condition where the nerves or blood vessels in the neck or underarm are compressed. This can be due to muscle swelling or bone-related issues in the neck. It can also occur due to vascular injuries or from frequent overuse in sports activities.
Shoulder joint injuries could include conditions like dislocation, injury to the AC joint, pinching of structures in the shoulder, or tears in the rotator cuff muscles. These injuries often arise from traumatic events and can be identified using imaging techniques such as X-rays or MRI scans. Any resulting nerve problems are often temporary.
Issues with the cervical spine (neck area) can result in conditions such as neck sprain or nerve root pain. Patients may experience symptoms including neck and arm pain on one side, muscle weakness, and unusual sensations like tingling or numbness. These symptoms can be traced back to specific nerves as follows:
- C4 radiculopathy (nerve root pain): Scapular winging, which refers to the shoulder blade sticking out.
- C5 radiculopathy: Weakness in the deltoid and biceps muscles, located at the shoulder and upper arm.
- C6 radiculopathy: Weakness in the brachialis muscle and in the ability to extend the wrist; numbness in the thumb and index finger.
- C7 radiculopathy: Weakness in the triceps muscle and in the ability to flex the wrist; numbness in the middle finger.
- C8 radiculopathy: Issues with fine motor skills in the hand or numbness in the ring and little fingers.
