What is a Nerve Biopsy?

Nerve Biopsy is a procedure where a sample of a peripheral sensory nerve is removed and studied for specific or supportive diagnostic information. It is invasive, expensive, and may not provide a specific diagnosis. However, it does provide a role in supporting the diagnosis along with clinical examination, whereas other tests such as nerve conduction studies are limited.

Indications for performing a Nerve Biopsy procedure include:

• Vasculitis
• Amyloidosis
• Sarcoidosis
• Leprosy
• Tumor infiltration
• Fabry’s disease
• Giant axonal neuropathy (GAN)
• Adult polyglucosan body disease (APBD)
• Hexacarbon neurotoxicity
• Hereditary neuropathy with liability to pressure palsies
• Glycogen storage diseases (GSDs)
• Chronic inflammatory demyelinating neuropathy
• Charcot Marie Tooth disease
• Other demyelinating neuropathies       

How is a Nerve Biopsy procedure performed?

• The procedure is typically performed in an outpatient setting by a neurologist
• Local anesthesia is administered
• A minimum of 6 cm of nerve segment is removed in order to perform all the required diagnostic tests
• The entire procedure may take about 2-3 hours
• Patients can experience pain after the procedure, which usually resolves in 2-3 weeks. However, some discomfort and numbness can persist for longer. Allodynia, which is a heightened sensation of discomfort with non-painful stimuli, is also reported for up to a year after the procedure
• 90% of patients should have complete recovery from sensory loss within 18 months of the biopsy, though persistence of sensory loss and allodynia has been observed until years later. The resolution of sensory loss is due to surrounding nerve fibers taking over the functioning

The most common site for Nerve Biopsy is the sural nerve (located in the leg). A concomitant muscle biopsy of the gastrocnemius (calf muscle in the leg) is performed in select cases, depending on the diagnosis. The tissue is processed using multiple methods. High resolution light microscopy is then used to study the nerves. In certain cases, electron microscopy, biochemical, or DNA analysis may be needed.  Even though the Nerve Biopsy does not yield a specific diagnosis in many cases, the pattern of abnormalities seen will aid in the diagnosis.