What is a Pinched Nerve? Nerve Compression, Entrapment

Nerve compression or pinched nerve, sometimes referred to as nerve entrapment, is a condition where a single nerve or a group of nerves is affected by pressure on the nerves. This is usually due to compression, constriction or stretching of the nerve to produce symptoms such as pain or discomfort along the course of the nerve, tingling or numbness and muscle weakness. In most cases, the condition is short-lived and patients recover fully with conservative treatment, but if the pressure on the nerve is allowed to continue, it may lead to chronic pain and permanent nerve damage, requiring surgical intervention.

What does a pinched nerve feel like?

Signs & Symptoms of Nerve Compression

Symptoms may vary from mild to severe, depending upon the pressure on the nerve, and result in a temporary or permanent condition according to the duration of nerve compression. A foot or hand “falling asleep” or experiencing “pins and needles” is a simple example of nerve compression. According to the site of compression, there may be added features, but the general symptoms of nerve compression are :

  • “Pins and needles” or tingling sensation, also known as paresthesia.
  • Burning sensation
  • Numbness or decreased sensation in the area supplied by the nerve
  • Pain radiating outwards from the injured area
  • Muscle weakness
  • Twitching of the muscles
  • Coughing, sneezing or straining may aggravate the condition, with increased sensation, especially if the nerve originates in the spinal cord.
  • A foot or hand “falling asleep”.

How does a pinched nerve occur?

Causes of Nerve Compression

Pressure on a nerve by the surrounding tissues, such as bone, cartilage, muscle or tendon, results in disruption of nerve function and symptoms of a pinched nerve, or nerve compression.

Picture from Laserspineinstitute.com
Picture from Laserspineinstitute.com

The cause of nerve compression may be :

  • A herniated spinal disc may cause compression of the nerve root
  • Spinal stenosis or narrowing of the spinal column
  • Injury
  • Inflammation
  • Narrowing of the bony tunnel through which the nerve passes, due to bone enlargement, swollen tendon sheath or thickening of the ligament.
  • Osteoarthritis
  • Poor posture
  • Obesity
  • Repetitive finger and hand movements on the computer or mobile phone
  • Repetitive activities in sports such as tennis.
  • Jobs that require repetitive hand, wrist or shoulder movements.

What are the conditions associated with a pinched nerve?

Conditions Resulting from Nerve Compression

Different conditions arise as a result of nerve compression at different sites. Nerve compression may occur at any level along the vertebral column as a result of injury or inflammation.

  • Carpal tunnel syndrome occurs due to compression of the median nerve as it passes through the carpal tunnel at the wrist. There is pain and paresthesia along the distribution of the median nerve with the thumb, index and middle finger and half of the ring finger. In later stages there may be muscle wasting of the palm. Carpal tunnel syndrome is a very common condition, occurring most frequently in women between 30 to 50 years of age. Some of the factors predisposing to it are rheumatoid arthritis, hypothyroidism, diabetes mellitus, acromegaly, certain immune system diseases and edema of the carpal tunnel produced during pregnancy. Activities requiring repetitive flexion and extension of the wrist may also play a part in developing this syndrome.
  • Radial tunnel syndrome is the compression of the radial nerve in the forearm.
  • Cubital tunnel syndrome or “tennis elbow” is the compression of ulnar nerve at the elbow. Leaning on the elbow or prolonged flexion of the elbow may produce this syndrome.
  • Peroneal nerve compression.
  • Femoral nerve compression.
  • Sciatica is when the sciatic nerve may be trapped, producing the typical symptom of pain radiating down from the lower back, through the buttocks and down the legs. Sciatica may occur due to pressure on the nerve by a herniated lumbar disc or the pyriformis muscle.
  • Radiculopathy is nerve irritation as a result of a damaged disc. This may be due to degeneration of the disc due to normal wear and tear associated with age or as a result of injury. The spine is made up of vertebrae, with an intervertebral disc positioned between each vertebra to act not only as a cushion and shock absorber but also to provide mobility and flexibility to the spine. The disc is composed of an outer ring protecting the soft center, and when this outer ring is damaged the disc may protrude or rupture, causing radiculopathy.

Depending on the level at which this occurs, there will be symptoms of :

  1. Cervical radiculopathy – irritation of one or more nerves in the neck (between cervical vertebrae). This may cause tingling, “pins and needles” sensation or burning pain in one or both arms.
  2. Thoracic radiculopathy – pinched nerve in the thoracic (mid back or chest) region may cause pain in the mid back, shoulder blades and chest.
  3. Lumbar radiculopathy – most often causes sciatica or pain along the sciatic nerve distribution (lower back). There is burning or radiating pain, shooting all the way down from the lower back, through the buttocks, down the back of legs, often reaching till the feet. The sensation may be on one side or on both sides and may be associated with numbness and tingling.
  • Piriformis syndrome causes symptoms of sciatica due to compression of the sciatic nerve by the pyriformis muscle. Athletes such as runners and cyclists are more prone to develop this syndrome, as also people with jobs where they are required to sit all day.
  • Cauda equina syndrome involves the bundle of nerves, called the cauda equina, which extend down from the bottom of the spinal cord and over the sacrum. The cauda equine may be compressed by a ruptured or herniated disc, tumor, injury or swelling due to an inflammation, resulting in pain in the lower back with reduced sensation in the buttocks, thighs, bladder and rectum.
  • Peripheral neuropathy
  • Cervical spondylosis occurs when there is degeneration of the discs and vertebrae of the neck, causing pressure on the spinal cord in the neck. This usually affects middle-aged or older people and in most cases is due to osteoarthritis. The initial symptoms may be unsteady walk, with pain and loss of flexibility of the neck.

How is a pinched nerve diagnosed?

Tests to Diagnose Nerve Compression

Diagnosis is often possible clinically on taking proper history and on examination of the patient, but in case of severe symptoms and if diagnosis is uncertain, certain tests may be done.

  • Nerve conduction study or nerve conduction velocity test where patch type electrodes are placed on the skin and the nerve is stimulated with a mild electrical impulse. This produces an effect like an electric shock and is done to assess any nerve damage.
  • Electromyography (EMG) is a test done to measure the electrical discharges produced in muscles and it gives information of any damage to the nerves leading to the muscle.
  • Magnetic resonance imaging or MRI may be done to obtain information about any nerve root compression in the spine.
  • Computed tomography or CT scan.
  • X-ray
  • Myelograms enhance the diagnostic imaging of an x-ray or CT scan by injecting a contrast dye.

How is a pinched nerve treated?

Treatment of Nerve Compression

  • Rest to the affected area.
  • Avoiding any activity that initiates or aggravates the condition.
  • Immobilization of the area by a splint, brace or collar. In case of carpal tunnel syndrome, a splint may need to be used both in the daytime and at night.
  • Physiotherapy and exercises to strengthen the muscles in the affected area.
  • Drugs to help in relieving pain and inflammation include :
  1. NSAIDs – nonsteroidal anti-inflammatory drugs such as ibuprofen and naproxen.
  2. Corticosteroid injections into the affected area.
  • Surgery may be required to release the pressure on the nerve if the symptoms of nerve compression do not improve with conservative treatment. Depending on the location and type of compression, surgery may involve removal of bone spurs or part of a herniated disc in the spine, or incising the carpal ligament to relieve pressure on the nerve.

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