Sural Nerve Biopsy

When nerve symptoms don’t have a clear cause, it can be frustrating to keep searching for answers. A sural nerve biopsy is a small outpatient procedure that lets doctors look at a nerve under the microscope to find the reason behind the problem.

What Is a Sural Nerve Biopsy?

The sural nerve is a small sensory nerve that runs down the back of the calf to the outer side of the ankle and foot. It carries feeling only, with no role in muscle strength, which makes it a safe nerve to sample. In a sural nerve biopsy, a short piece of the nerve is removed and studied by a specialist to diagnose conditions that affect the peripheral nerves.

Who Needs a Sural Nerve Biopsy?

A nerve biopsy is usually requested by a neurologist when blood tests, nerve conduction studies and other testing haven’t explained a neuropathy. It can help diagnose:

• Inflammation of the blood vessels supplying the nerves (vasculitis)
• Inflammatory neuropathies, such as chronic inflammatory demyelinating polyneuropathy (CIDP)
• Amyloidosis and other deposits in the nerve
• Certain infections, inherited neuropathies and rare conditions

Other Tests First

• Blood tests: for diabetes, vitamin levels, thyroid problems, autoimmune and other causes
• Nerve conduction studies and EMG: to show which nerves are affected and how
• Skin biopsy: sometimes used to look at small nerve fibers

A nerve biopsy is considered when the answer could change your treatment.

How a Sural Nerve Biopsy Is Done

1. Anesthesia: An outpatient procedure, usually with numbing medicine, sometimes with light sedation.
2. Incision: A small incision is made on the outer side of the ankle or lower calf.
3. Taking the sample: A short segment of the sural nerve is removed and sent to a specialized laboratory.
4. Closing: The incision is closed with stitches and a dressing is applied.

Benefits and Risks

Benefits

• Can provide a diagnosis when other tests haven’t
• Can identify treatable causes, such as vasculitis or inflammatory neuropathy
• Usually a quick, same-day procedure

Risks

• A permanent small patch of numbness on the outer side of the foot, which is expected
• Tingling or discomfort at the biopsy site, which usually fades over time
• Infection or slow wound healing, especially in people with diabetes or poor circulation
• A biopsy that doesn’t provide a definite answer

Why Choose Dr. Betsy Grunch for Your Sural Nerve Biopsy

• Duke-trained: Dr. Grunch completed her neurosurgical residency at Duke University School of Medicine, one of the top neurosurgery programs in the country.
• Working with your neurologist: Dr. Grunch coordinates with the doctor who requested the biopsy so the sample is handled correctly and the results get back to the right team.
• Experience you can count on: She has been in practice since 2013 and performs 400 to 600 surgeries a year, more than 5,000 procedures over her career.
• A teacher at heart: As “Ladyspinedoc,” she is known for explaining nerve and spine conditions clearly. You’ll leave your visit understanding your diagnosis and every option in front of you.

What to Expect

Before the biopsy

You’ll meet with Dr. Grunch or one of her physician assistants to review your symptoms, exam and nerve testing, and to decide together whether a sural nerve biopsy is right for you. Our team will review your medications (including blood thinners you may need to pause) and coordinate with your neurologist about which leg and which tests are needed.

Procedure day

The biopsy usually takes 30 to 60 minutes, and you go home the same day.

Recovery timeline

• First days: Keep the leg raised and limit walking to what you need.
• Two weeks: Stitches are removed at your follow-up visit.
• Several weeks: Results from the specialized laboratory can take a few weeks and are shared with you and your neurologist.
• Months: Tingling at the site usually settles, and the numb patch becomes less noticeable.

Caring for yourself at home

• Your incision: Remove the dressing on day three and leave the stitches in place. You may shower starting day three. Gently clean the incision and pat it dry without scrubbing. Leave it open to air, and don’t use ointments or creams. A small amount of brownish-red drainage for a few days is normal.
• No soaking: Don’t soak the incision in a bath, hot tub or pool for six weeks and until any scabs are gone.
• Swelling: For the first few days, raise your leg above the level of your heart for about 30 minutes every two to three hours.
• Activity: Walk short distances, and avoid long periods on your feet and strenuous exercise for about two weeks. Protect the incision from bumping or rubbing on hard surfaces.
• Medications: Take pain medication with food and avoid alcohol while taking it. Most people need it for up to two weeks. Take a daily stool softener and a laxative as needed. Don’t take blood thinners such as aspirin, warfarin, Xarelto or Plavix for five to seven days after surgery, until the office tells you to restart them.
• Driving: You may drive once you’re no longer taking narcotic pain medication. Riding as a passenger is fine.
• Smoking: Smoking slows healing. Our office can help if you’d like to quit.
• Follow-up: Your visit is about two weeks after surgery, when any stitches are removed. If you can’t work during recovery, our office can complete employer paperwork.

Call the office at 470-293-9800 if you have a fever over 101°F, redness, warmth or significant drainage from the incision, new weakness or numbness that wasn’t there before surgery, calf pain or swelling, or constipation that medication doesn’t relieve. Call 911 for chest pain or shortness of breath.

Download your patient instructions

Your instructions depend on the type of surgery you have. Our team will give you written instructions before you go home, and you’ll find other patient sheets on our Patient Resources page.

Frequently Asked Questions

Will I lose strength in my foot?

No. The sural nerve carries feeling only, so removing a small piece doesn’t affect strength.

Will I have numbness afterward?

Yes, a small area on the outer side of the foot and ankle will be numb. Most people find it becomes less noticeable over time.

How long do results take?

Usually a few weeks, because the nerve is studied with special stains and microscopes.

Who decides if I need a nerve biopsy?

Usually your neurologist, when other tests haven’t explained your neuropathy and the result could change your treatment.

Is a nerve biopsy painful?

The area is numbed during the procedure. Afterward, soreness is usually mild and improves within a couple of weeks.

Take the Next Step

If your neurologist has recommended a nerve biopsy, our team is here to help. Dr. Grunch and the Southern Neurosurgery team will work closely with your neurologist.

Call 470-293-9800 to schedule an appointment or contact us online.

Have a question first? Ask our virtual assistant anything, 24/7.

We see patients across metro Atlanta and North Georgia at our offices in Gainesville, Sandy Springs and South Atlanta (Riverdale). Find the office nearest you.

Related pages: Peripheral neuropathy · Neuropathic pain · Peroneal nerve decompression · Peripheral nerve decompression

This page is for educational purposes only and is not medical advice. It does not replace individualized care from a licensed physician. If you have sudden weakness, numbness or loss of function, call 911 or go to the nearest emergency room.