Nerve Biopsies: Frequently Asked Questions
Because it is an invasive procedure, nerve biopsy is appropriate for the diagnosis of serious nerve disease. Possible diseases which require assessment by nerve biopsy may include vasculitis, amyloid and neuropathy. Inflammatory disease of the nerve can be diagnosed by biopsy and it is often important to firmly establish diagnosis before initiating certain medical regimens. Nerve biopsy is performed under local anesthesia and is an outpatient procedure. Typically completed in one to two hours, patients can expect to spend one half day or more at the outpatient center in preparation and follow-up for the procedure.
Surgeons at any hospital or surgical facility who are familiar with diagnostic nerve biopsy procedures can obtain a specimen, which should then be sent directly to the Neuromuscular Pathology Laboratory for staining and interpretation.
Biopsies can also be performed at the Johns Hopkins Outpatient Center and for inpatients at The Johns Hopkins Hospital. Patients can expect to spend one half day or more at the outpatient center in preparation and follow-up for the procedure. The tissues obtained at the time of biopsy are prepared in the Neuromuscular Pathology Laboratory at Johns Hopkins.
Nerve tissue obtained at biopsy is studied in great detail at Johns Hopkins. Frozen sections of nerve tissue are routinely prepared with the following stains:
- Acid phosphatase
- Gomori trichrome
- Congo red
Patients undergoing nerve or muscle biopsy will receive instructions in advance. Patients should not take aspirin, aspirin containing products, or nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen for 10 days prior to the procedure. Patients taking Coumadin, Lovenox, Plavix or Ticlid will need to follow specific instructions relating to these medications.Our staff will secure a patient’s insurance authorization once the appropriate referral forms have been completed.
Patients who have a nerve biopsy in the leg must expect to use crutches or another assistive device for two full days after biopsy. Training with crutches is provided. Stitches do not need to be removed but must remain completely dry for two days.
Staples, when used, will require professional removal 21 or 28 days after the biopsy. In general there are few complications and the resulting scar heals well. Removal of the nerve at biopsy can result in a small numb patch which may resolve over time.
The results of pathological studies are interpreted by designated neuromuscular specialists in the Johns Hopkins Department of Neurology.
After the biopsy, a report on frozen or paraffin specimens will be sent to the referring physician, generally within one to two weeks. A report on plastic nerve specimens will be provided in three to four weeks.
If you have any questions or concerns, please contact 410-614-4278.
Protocol for Sending Nerve Biopsy Specimens
Notify the Lab
Please notify the Neuromuscular Pathology Laboratory two days in advance that a nerve specimen will be arriving. Please contact:
Obtain and Prepare the Specimen
A surgeon familiar with a diagnostic nerve biopsy procedure should obtain the specimen. Full thickness nerve approximately 4 cm in length is needed.
The nerve is handled as follows. The nerve is placed on a 3x5 index card by the surgeon or the technician. DO NOT STRETCH THE NERVE. Work on the index card. Cut the nerve into 3 sections as detailed below with a double-edged super stainless blade on the index card.
- Cut a 1 cm piece for section #1 and place it on the top left hand corner of the card.
- Cut the card around the nerve and place it face down in a container of 4% paraformaldehyde prepared as follows: For 24 ml total solution (or 2 bottles), pour 12 ml 8% Paraformaldehyde and 12 ml 0.2M Sorensen's Phosphate buffer into a graduated cylinder.
- Mix well by placing parafilm over top of cylinder and inverting several times.
- Pour 13 ml of this solution into a biopsy fixative bottle and label as 4% Paraformaldehyde.
- Use the remaining 11 ml solution to prepare the 3% glutaraldehyde/4% paraformaldehyde needed below.
- Cut a 2 cm piece for section #2 and place it at the bottom of left hand corner of the card.
- Cut #2 into 3 smaller pieces.
- Cut the card around the nerve and place it face down in container marked 3% glutaraldehyde/4% paraformaldehyde prepared as follows: Into the remaining 11 ml of 4% paraformaldehyde solution add .7 ml of 50% Glutaraldehyde.
- Mix well by stirring with a pipet. Pour this solution into a 2nd fixative bottle and label 3%Glutaraldehyde/4%Paraformaldehyde.
- Pin one end of the remaining nerve section #3 (1-2 cm) to the index card and freeze it in 2-methylbutane (isopentane) in a metal cup surrounded by dry ice in a rubber bucket.
- Cool the methylbutane in advance by dropping small pieces of dry ice into the methylbutane (see muscle protocol).
- When the nerve segment is thoroughly frozen, pack section #3 in sufficient dry ice and the other sections in regular ice.
Ship the Specimen
Ship overnight to:
The following information will be needed. Tissue samples cannot be processed unless this information is provided with the specimen.
- Patient's name, address, date of birth, and hospital ID number
- Hospital charge number for billing directly to the hospital
- Brief clinical history
- Identification of muscle biopsy site, date, and time
- Name, address, phone and fax # of referring pathologist and attending physicians