A nerve biopsy is a procedure where a small sample of a nerve is removed from your body and examined in a laboratory.
Nerve biopsy can identify potentially treatable causes of neuropathy, such as vasculitis, atypical CIDP, sarcoidosis, amyloidosis, lymphomatosis, or leprosy, when other tests fail to diagnose these conditions. Given that it is an invasive test, however, a nerve biopsy is usually only recommended when the neuropathy is progressive, threatens to become debilitating, and other tests fail to identify a cause. (Oh, 1990; Midroni and Bilbao, 2006; Schroder, 1998). Vasculitis, amyloidosis, sarcoid and other multifocal disorders may also affect skeletal muscle so that biopsy of muscle in addition to nerve may increase the diagnostic yield.
Why a Nerve Biopsy Is Done
Your doctor may request a nerve biopsy if you are experiencing numbness, pain, or weakness in your extremities. You might experience these symptoms in your fingers or toes.
A nerve biopsy can help your doctor determine whether your symptoms are caused by:
- damage to the covering of a nerve (called the myelin sheath)
- damage to the small nerves
- destruction of the axon in the nerve cell (the fiber-like extensions of the cell that help carry signals)
- neuropathies (inflammatory nerve conditions)
Numerous conditions and nerve dysfunctions can affect your nerves. Your doctor may order a nerve biopsy if they believe you may have one of the following conditions:
- alcoholic neuropathy
- axillary nerve dysfunction
- brachial plexopathy
- Charcot-Marie-Tooth disease
- common peroneal nerve dysfunction
- distal median nerve dysfunction
- mononeuritis multiplex
- necrotizing vasculitis
- radial nerve dysfunction
- tibial nerve dysfunction
Risks of a Nerve Biopsy?
The major risk associated with a nerve biopsy is long-term nerve damage. But this is extremely rare since your surgeon will be very careful when choosing which nerve to biopsy. Typically, a nerve biopsy will be done on the wrist or the ankle.
According to New York University Medical Center, it’s common for a small area around the biopsy to remain numb for about six to 12 months after the procedure. In some cases, the loss of feeling will be permanent. But because the location is small and unused, most patients are not bothered by it.
Other risks might include minor discomfort after the biopsy, allergic reaction to the anesthetic, and infection. Talk to your doctor about how to minimize your risks.