A nerve biopsy is a minor operation to remove a small sample of nerve for normal testing to cure the diagnosed disease. The operation is performed under local anesthesia. The patient will be asked to lie down, and a local anesthesia will be given where the biopsy will be done. A small incision is made, and the nerve is carefully opened up. Then, the sample of the nerve is taken.
The wound is then stitched. Self-dissolving stitches are used under 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. The sural nerve which is present 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 conducted for calculation of specific 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 may sometimes become infected, so the patient should regularly consult his treating physician. If the wound is found to be red or swollen, then the treatment with antibiotics may be appropriate.
If the patient is having pain or discomfort after the biopsy, when the local anesthesia 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 can lead to loss of sensation or altered sensation, including a prickling sensation 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 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 the patient’s condition and the 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 anesthesia to numb the area, the patient will feel a needle pricking 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, the patient 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.
After the Nerve Biopsy
- Once the patient gets 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. Some of the different tests are performed depending on the suspected diagnosis. The procedure can take at least one week or more. This is followed by detailed analysis leading to a full report, which may take up to three or 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.