Authored by MCN Neurologists
Entrapment neuropathy arises due to nerve damage resulting from chronic mechanical compression.
The area involved depends on the exact nerve that is entrapped. Symptoms include pain and/or numbness and/or weakness.
The most common nerve entrapment is carpal tunnel syndrome, which results from chronic compression of the median nerve at the wrist. Symptoms include hand pain and numbness and grip weakness. Other common nerve entrapment syndromes include ulnar neuropathy at the elbow or wrist and lateral femoral cutaneous neuropathy, also known as meralgia paresthetica.
Ulnar neuropathy, similar to carpal tunnel syndrome, can result in hand pain, numbness and weakness. Lateral femoral cutaneous neuropathy results in numbness and pain in the lateral aspect of the thigh.
Nerve damage results from chronic mechanical injury to the entrapped nerve. Typically the sites of injury are locations where the nerve is close to bones and ligaments that provide only a small passage for the nerve to travel through. Over time, the repetitive rubbing, sliding or compression results in nerve damage. More rarely, nerves can be entrapped between muscles or other organs resulting in injury.
Examination and Tests
Your physician will complete a thorough history and physical examination to understand the nature of the injury. Images, including x-rays, CT scans and MRI scans, may be needed to assess the area of entrapment. An EMG (electromyogram) may also be ordered to define the location and/or severity of the injury. Blood tests may be performed to look for non-mechanical causes of nerve damage.
Treatment will vary depending on the location and severity of the nerve entrapment. For nerve entrapments in the arm, patients are frequently given splints or braces to try and reduce the amount of mechanical compression. In more severe cases, surgery may be needed to actually release the nerve from the area of entrapment. Physical therapy can often play a role in relieving symptoms by reducing entrapment. Some patients may need prescription medications or injections to help manage the pain of the injury.
Changing physical activities can often help reduce the injury, when nerve entrapment injuries are caught early. Similarly, those persons, who are at high risk for entrapment neuropathies, could change their activities and reduce their risk prior to nerve injury occurring. For example, people, who are involved in activities that require repetitive motion with their hands, are at high risk for carpal tunnel syndrome. By varying their activities and taking breaks from repetitive tasks, such as typing, people can reduce the risk of developing the problem. Ergonomic workstation designs can sometimes prevent entrapment nerve injuries and weight reduction can reduce the risk for nerve entrapment in the legs. Again, physical therapy is able to provide recommendations for adaptations in posturing and ergonomics to prevent or minimize the progression of many entrapment neuropathies.
For further information about entrapment neuropathies, click on the following links:
For more information on carpal tunnel syndrome
http://www.ninds.nih.gov/disorders/carpal_tunnel/detail_carpal_tunnel.htm (National Institute of Neurological Diseases and Stroke)
For more information regarding meralgia paresthetica
http://www.ninds.nih.gov/disorders/meralgia_paresthetica/meralgia_paresthetica.htm (National Institute of Neurological Diseases and Stroke)