A nerve biopsy is the removal of a small piece of a nerve for examination.
Biopsy - nerve
How the Test is Performed
A nerve biopsy is most often done on a nerve in the ankle, forearm, or along a rib.
The health care provider applies medicine to numb the area before the procedure. The doctor makes a small surgical cut and removes a piece of the nerve. The cut is then closed and a bandage is put on it. The nerve sample is sent to a lab, where it is examined under a microscope.
How to Prepare for the Test
There is no special preparation.
How the Test will Feel
When the numbing medicine (local anesthetic) is injected, you will feel a prick and a mild sting. The biopsy site may be sore for a few days after the test.
Why the Test is Performed
Nerve biopsy may be done to help diagnose:
- Axon degeneration (destruction of the axon portion of the nerve cell)
- Damage to the small nerves
- Demyelination (destruction of parts of the myelin sheath covering the nerve)
- Inflammatory nerve conditions (neuropathies)
Conditions for which the test may be done include any of the following:
- Alcoholic neuropathy (damage to nerves from excessive drinking of alcohol)
- Axillary nerve dysfunction (damage to the shoulder nerve that leads to a loss of movement or sensation in the shoulder)
- Brachial plexopathy (damage to the brachial plexus, an area on each side of the neck where nerve roots from the spinal cord split into each arm's nerves)
- Charcot-Marie-Tooth disease (inherited group of disorders that affect the nerves outside the brain and spine)
- Common peroneal nerve dysfunction (damage to the peroneal nerve leading to loss of movement or sensation in the foot and leg)
- Distal median nerve dysfunction (damage to the median nerve leading to loss of movement or sensation in the hands)
- Mononeuritis multiplex (disorder that involves damage to at least two separate nerve areas)
- Necrotizing vasculitis (group of disorders that involve inflammation of the blood vessel walls)
- Neurosarcoidosis (complication of sarcoidosis, in which inflammation occurs in the brain, spinal cord, and other areas of the nervous system)
- Radial nerve dysfunction (damage to the radial nerve leading to loss of movement or sensation in the arm, wrist or hand)
- Tibial nerve dysfunction (damage to the tibial nerve leading to loss of movement or sensation in the foot)
A normal result means the nerve appears normal.
What Abnormal Results Mean
Abnormal results may be due to:
- Amyloidosis (sural nerve biopsy is most often used)
- Inflammation of the nerve
- Loss of axon tissue
- Metabolic neuropathies (nerve disorders that occur with diseases that disrupt the chemical processes in the body)
- Necrotizing vasculitis
Risks of the procedure may include:
- Allergic reaction to the local anesthetic
- Discomfort after the procedure
- Infection (a slight risk any time the skin is broken)
- Permanent nerve damage (uncommon; minimized by careful site selection)
Nerve biopsy is invasive and is useful only in certain situations. Talk to your provider about your options.
Chernecky CC, Berger BJ. Nerve biopsy - diagnostic. In: Chernecky CC, Berger BJ, eds. Laboratory Tests and Diagnostic Procedures. 6th ed. St Louis, MO: Elsevier Saunders; 2013:814-815.
Shy ME. Peripheral neuropathies. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 420.