Nerve entrapment is a medical syndrome that develops when nerves become compressed (or entrapped) and restricted. This occurs due to a variety of causes, from trauma or injury to repeated or overuse activity.
Nerve entrapment syndrome is also known as:
- Nerve compression syndrome
- Entrapment neuropathy
- Compression neuropathy
- Trapped nerve
Nerve entrapment negatively impacts the nerve’s ability to do its job: send and receive messages from the brain. This is due to the impact of the nerve condition, which may include swelling, reduced blood flow and damage to the surrounding structures.
Types of Nerve Entrapment
Peripheral neuropathies are relatively common clinical disorders. The peripheral nerve system is a network of 43 pairs of motor and sensory nerves that connect the central nervous system (the brain and spinal cord) to the entire human body.
Although nerves may be impacted anywhere along the route they travel, and nerve entrapment may occur in nerves in the torso, limbs and extremities, peripheral nerve compression or entrapment occurs more at specific locations, most likely at sites where the nerves pass through narrow, tunnel-like structures.
The most common types of nerve entrapment are:
- Carpal tunnel syndrome (carpal nerve compression, at the wrist)
- Cubital tunnel syndrome (ulnar nerve compression, at the elbow)
- Herniated disc (in the spine)
- Peroneal nerve entrapment (in the knee)
Rarer types of nerve entrapment include:
- Suprascapular nerve entrapment (in the shoulder)
- Ulnar tunnel syndrome (in the wrist)
- Radial nerve compression syndrome (in the arm)
- Meralgia paresthetica (compression of the lateral femoral cutaneous nerve, affecting skin of thigh)
Symptoms of nerve entrapment vary. For some, pain is the sole symptom. Others may be pain-free, but experience any of the common symptoms listed below.
- Pain, generally in the area of the compressed nerve, but also possibly radiating outward. Pain may be sharp, aching or burning.
- “Pin and needles” (paresthesia) or tingling sensations
- Muscle weakness, especially with activity involving the affected nerve
- Numbness, particularly in the hand or foot
There are a variety of causes of nerve entrapment. It can be caused by trauma, such as from sprains or bone fractures, but is often due to repetitive or overuse activities. Duties in jobs or sports are examples. Even pregnancy that causes swelling of the extremities can result in compressed nerves. There is also a correlation to heredity; a person is more susceptible if he/she has a family member with a condition that lends itself to nerve entrapment. Some conditions that can cause nerve entrapment are:
- Tumors or cysts
- Autoimmune disorders
- High blood pressure
- Cancer or cancer treatments
- Neurological disorders
- Birth defects
- Thyroid disorders
A diagnosis of nerve entrapment begins with a review of symptoms, such as a patient’s experience with pain, tingling, numbness or other signs. A general background review of other medical conditions and habits may also provide useful information to identify the affected nerves.
Physical tests during an exam include testing the muscle strength and sensations. Following the physical exam, additional tests may be prescribed. X-rays are done if an injury or arthritis of the spine may be suspected. A CT or MRI can reveal a pinched nerve and provide useful information to determine surgical treatment.
One of the most common tests conducted is an electromyography (EMG), or nerve conduction study. This test measures the speed of the nerve impulse as it travels, thus assessing the function of the nerve.
Surgery for nerve entrapment was first performed more than a century ago. Today, among neurosurgeons, nerve entrapment treatments make up a sizeable part of a practice.
Before surgery is considered, all conservative options are exhausted. That being said, symptoms that linger should be addressed. It is vital that nerve entrapment be evaluated and treated as soon as possible. The sooner the treatment, the greater the odds of preventing any permanent nerve damage.
- Medication – Nonsteroidal anti-inflammatory drugs (NSAIDs); oral corticosteroids
- Steroid injections
- Physical therapy