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Neuromuscular Pathology Laboratory

The Johns Hopkins Department of Neurology offers comprehensive services for the evaluation of nerve and muscle disease, including:

  • Clinical evaluation
  • Nerve and muscle biopsy
  • Tissue preparation
  • Pathological interpretation

Nerve and muscle biopsies are performed by specially trained physicians, usually as an outpatient procedure. Nerve and muscle tissues are prepared by the clinical specialty laboratories in the Department of Pathology. The results of pathological studies are interpreted by designated neuromuscular specialists in the department.

Contact Information

  • Neuromuscular Lab: 410-502-7260
  • Reference Histology: 410-955-3620

Our Services: Muscle Biopsy Analysis

Protocol for Sending Outside Biopsy Specimens

Outside nerve and muscle biopsy tissues may be sent to the Department of Pathology Laboratory for staining and interpretation; instructions for nerve and muscle processing are available on this web site. Specimens that have been obtained and stained elsewhere may be referred for neuropathological consultation (second opinion).

Protocol for Sending Nerve Biopsy Specimens

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.

Section 1

  • 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.

Section 2

  • 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.

Section 3

  • 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 Johns Hopkins Medical Institutions
Department of Pathology
ATTN: Surgical Pathology – Nerve and Muscle Biopsies
600 N. Wolfe Street
Pathology 7th Floor, Room 700
Baltimore, MD 21287

Phone: 410-955-3620 or 410-502-7260
Email: [email protected]

The following information will be needed. Tissue samples cannot be processed unless this information is provided with the specimen. The attached requisition must accompany the sample and contain all of the information listed below.

  • 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

Protocol for Sending Muscle Biopsy Specimens

Obtain the Specimen

A surgeon familiar with the diagnostic muscle biopsy procedure should obtain the specimen. Three strips of muscle approximately 2.5 cm x 0.5 cm parallel to the direction of the muscle fibers should be obtained. A muscle that is moderately but not severely weak should be used for the biopsy (4/5 on the British Medical Research Council Scale).

Electron microscopy of muscle is not routinely done but rarely indicated. If electron microscopy is requested, please contact Dr. Ahmet Hoke at 410-614-1196 before the biopsy is done as the tissue must be fixed in a special fixative at the time of the biopsy.

Send the Specimen

It is preferable that the specimen be delivered fresh within one hour after excision. If this is possible, wrap the muscle in a piece of saline-moistened gauze and place it in a container or plastic bag. DO NOT IMMERSE BIOPSY SAMPLES IN SALINE. Place in a styrofoam container with regular ice and send immediately by special messenger to:

The Johns Hopkins Medical Institutions
Department of Pathology
ATTN: Surgical Pathology – Nerve and Muscle Biopsies
600 N. Wolfe Street
Pathology 7th Floor, Room 700
Baltimore, MD 21287

Phone: 410-955-3620 or 410-502-7260
Email: [email protected]

Please notify us when to expect the specimen. The following information will be needed. Tissue samples cannot be processed unless this information is provided with the specimen. The attached requisition must accompany the sample and contain all of the information listed below.

  • 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

Specimen Freezing Procedure

If the specimen cannot be delivered in one hour, then it must be frozen immediately after excision, as follows:

  • Pour 2-methylbutane (isopentane) into a metal container that will hold a minimum of 200 ml.
  • Drop small pieces of dry ice into the liquid to cool it.
  • Surround the container with dry ice to keep it cold.

Immediately after excision, the muscle specimen should be stretched in the direction of the fibers to just beyond its in situ resting length, and pinned at each end to a small piece of stiff card (index card). Hold the piece of cardboard with the pinned muscle using a Kelly clamp or pair of forceps, and quickly immerse it in the cold liquid, vigorously shaking the card for 15-20 seconds. This technique disperses bubbles that form around the specimen which would otherwise prevent uniform freezing. When it is thoroughly frozen, pack the specimen in sufficient dry ice and ship overnight to:

The Johns Hopkins Medical Institutions
Department of Pathology
ATTN: Surgical Pathology – Nerve and Muscle Biopsies
600 N. Wolfe Street
Pathology 7th Floor, Room 700
Baltimore, MD 21287

Phone: 410-955-3620 or 410-502-7260
Email: [email protected]

Laboratory Staff

Ahmet Hoke, M.D., Ph.D.

Ahmet Hoke, M.D., Ph.D.
Director, Neuromuscular Division
Director, Neuromuscular Pathology Laboratory
Professor of Neurology
Professor of Neuroscience

Allan Belzberg, M.D.

Allan Belzberg, M.D.
Director, Peripheral Nerve Surgery
George J. Heuer Professor of Neurosurgery
Co-Director, Neurosurgery Pain Research Institute
Director, Brachial Plexus and Peripheral Nerve Clinic, Kennedy Krieger Institute
Professor of Neurosurgery
Professor of Plastic and Reconstructive Surgery

Clinical Laboratory Coordinators

Frequently Asked Questions

Nerve Biopsies

Below are some information about nerve biopsies.

About Nerve Biopsies

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.

How is nerve tissue studied 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:

  • H&E
  • Acid phosphatase
  • Gomori trichrome
  • Congo red

Paraffin-embedded sections stained with H&E are also routinely prepared. The principle analysis is performed on nerve tissue embedded in plastic. This procedure, while definitive, requires 3 to 4 weeks to be completed. Additional nerve tissue is routinely archived for future analyses.

Before the Procedure

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.

After the Procedure

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.

Biopsy Results

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 Dr. Ahmet Hoke at 410-614-1196.

Muscle Biopsy

Below are some information about muscle biopsy procedures.

About the Muscle Biopsy Procedure

Because it is an invasive procedure, muscle biopsy is appropriate for the diagnosis of serious muscle disease such as:

  • Myositis
  • Muscular Dystrophy
  • Toxic Myopathies
  • Vasculitis

Muscle biopsy is performed under local anesthesia and is an outpatient procedure typically completed in one hour or less. Patients can expect to spend half a day or longer at the outpatient center in preparation and follow-up for the procedure.

Surgeons at any hospital or surgical facility who are familiar with diagnostic muscle biopsy procedures can obtain a specimen, which then should 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.

How is muscle tissue studied at Johns Hopkins?

Muscle tissue obtained at biopsy is prepared for both frozen and paraffin sectioning at Johns Hopkins. Frozen sections of muscle tissue are routinely prepared using numerous different histochemical stains.

The standard staining battery on frozen tissue includes:

  • H&E
  • Modified Gomori trichrome
  • Acid phosphatase
  • Alkaline phosphatase
  • Esterase
  • NADH
  • COX/SDH
  • Congo red
  • PAS (with and without diastase)
  • Myophosphorylase
  • Sudan black
  • C5b-9
  • MHC-1
  • Fast Myosin Skeletal heavy chain
  • Slow Skeletal Myosin heavy chain

Paraffin embedded sections are done routinely and stained with H&E and when indicated with Congo red.

Immunohistochemical staining is available for:

  • C5b-9
  • CD 3
  • CD 8
  • CD 20
  • CD 68
  • MHC-1

Additional muscle tissue is routinely archived for future analyses.

Before the Procedure

Patients undergoing nerve or muscle biopsy will receive instructions in advance. Our staff will secure a patient’s insurance authorization once the appropriate referral forms have been completed.

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.

After the Procedure

Patients who have a biopsy in the leg must expect to use crutches or another assistive device for two full days after biopsy. Training with crutches is provided. Because of this, some patients may require assistance at home during the recuperation period.

Patients who have a biopsy in the arm must expect to wear a sling for two days.

Stitches do not need to be removed but must remain completely dry for two days. In general, there are few complications, and the resulting scar heals well.

Biopsy Results

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 Dr. Ahmet Hoke at 410-614-1196.