Reasons for Having a Nerve Biopsy

A nerve biopsy is a minor operation to remove a small sample of nerve for normal testing to cure diagnosis. The operation is performed under local anesthetic. The patient will be asked to lie down, and a local anesthetic will be given where the biopsy will be taken. A small cut is made, and the nerve is carefully exposed. The sample of nerve is then taken.

The wound is then stitched. Self-dissolving stitches are used beneath the skin and in the skin. A plaster is then applied. The patient should let the doctor know if he is allergic to any types of plaster. Sural nerve at the ankle is the most common site for nerve biopsy.

Reasons for having a Nerve Biopsy

If someone has neuropathic symptoms or disease, testing of a small piece of nerve may give important information on the type and severity of the disease. Nerve Biopsy is usually performed for evaluation of certain hereditary, autoimmune/inflammatory, infectious, and amyloid neuropathies.

Establishing a diagnosis can allow specific treatment to be given. In a portion of cases, the findings are nonspecific or reflect changes seen in an end stage nerve, and a precise diagnosis may not be made even after a biopsy.

Risks of the Nerve Biopsy

The wound may ooze a little, and this is normal. If there is excessive bleeding, the patient should seek medical advice. The wound can sometimes become infected, so the patient should consult his treating physician. If the wound looks red or swollen, then treatment with antibiotics may be appropriate.

If the patient is having pain or discomfort after the biopsy, when the local anesthetic has worn off, the patient should take simple painkillers such as Tylenol. The sural nerve supplies sensation to a small area on the outer portion of the foot. This may lead to loss of sensation or altered sensation, including a prickling sensation and/or discomfort, and occasionally persistent pain in these areas.

Patients with neuropathies already have sensory loss in these areas, and the sensory loss in these areas may not be appreciated. If pain at the biopsy site remains severe and/or becomes persistent, then the patient might need steroid injections or another surgical procedure to remove the tip of the biopsied nerve that may have formed neuroma (entangled nerve fibers).

Stages of the Nerve Biopsy

Before the Procedure

The physician will explain the nerve biopsy to the patient and offer him the opportunity to ask any questions that he might have about the procedure. The patient will be asked to sign a consent form that provides permission to perform the procedure. Read the consent form carefully and ask questions if something is not clear. Notify the doctor if the patient is sensitive to or are allergic to any medications, latex, tape, and anesthetic agents (local and general).Notify the doctor of all medications (prescribed and over-the-counter) and herbal supplements that the patient is taking. Let the doctor know if the patient is having a history of bleeding disorders or if he is taking any anticoagulant (blood-thinning) medications, aspirin, or other medications that affect blood clotting. It may be necessary for the patient to stop these medications prior to the procedure. The patient will need to arrange for someone to drive the patient home after the procedure.

During the Nerve Biopsy

A nerve biopsy is typically performed on an outpatient basis. Procedures may vary depending on your condition and your physician’s practices.

This routine is followed generally:

The patient will be asked to remove clothing and will be given a gown to wear. During the procedure, the patient will need to lie as still as possible. The skin over the biopsy site will be cleansed with an antiseptic solution and shaved if needed. As the physician injects a local anesthetic to numb the area, the patient will feel a needle stick and a brief stinging sensation. The doctor will then make an incision through the numbed skin and the fatty tissue under the skin and will expose the nerve. After this he/she will obtain the biopsy specimen. The patient may feel a shooting sensation during the procedure. Low level of pain is not uncommon for Nerve Biopsy. The doctor will close the opening in the skin with stitches and adhesive strips. A sterile bandage/dressing will be applied. The nerve tissue sample will be sent to the laboratory for processing and examination.

After the Nerve Biopsy

Once the patient is home, it is important to keep the biopsy area clean and dry. Since self-absorbing stitches are used, they will not be removed by anyone. Adhesive strips usually will fall off within a few days itself. The biopsy site can be tender or sore for 2 to 3 days after a nerve biopsy. Take a pain reliever for soreness as recommended by the doctor. Aspirin or certain other pain medications may increase the chance of bleeding. Be sure to take only recommended medications. The patient may resume his usual activities as instructed by the doctor. Usually the patient will be required not to bear any weight with the biopsied leg for 2–3 days. Please keep this in mind when planning for the procedure. The doctor can give additional or alternate instructions to the patient after the procedure, depending on his particular situation.

Processing of the Muscle

The nerve biopsy is processed and examined under a microscope. Different tests are performed depending on the suspected diagnosis. The processing may take at least one week or more. This is followed by detailed analysis leading to a full report, which may take up to three to four weeks.

The result is sent to the referring doctor, who will then explain the findings to the patient. Any sample remaining after this analysis is stored in case further analysis or re-analysis is required in the future.