Myelofibrosis

Definition

Bone marrow aspiration, which is also called bone marrow sampling, is the removal by suction of fluid from the soft, spongy material that lines the inside of the bones. Bone marrow biopsy, or needle biopsy, is the removal of a small piece of bone marrow. The bone marrow is where blood cells are made.

Purpose

Bone marrow aspiration is used to:

• Pinpoint the cause of abnormal blood test results
• Confirm diagnosis or status of severe anemia from an unknown cause, other abnormalities in the blood's ability to store iron, or irregularities in the way blood cells are produced or become mature
• Diagnose infection

Bone marrow biopsy is used to:

• Obtain intact bone marrow for laboratory analysis
• Diagnose some types of cancer or anemia and other blood disorders.
• Identify the source of an unexplained fever
• Diagnose fibrosis of bone marrow and myeloma when bone marrow aspiration has failed to provide an appropriate specimen.

Bone marrow aspiration and bone marrow biopsy are also used to gauge the effectiveness of chemotherapy and other medical treatments. These procedures are often used together to ensure the availability of the best possible bone marrow specimen.

Description

These procedures should be performed by a physician or nurse clinician. Each procedure takes about 20-30 minutes. It is usually performed on an outpatient basis, but can be done in a hospital if necessary.

The skin covering the biopsy site is cleansed with an antiseptic, and the patient may be given a mild sedative. A local anesthetic is administered. The hematologist or nurse clinician performing the procedure will not begin until the anesthetic has numbed the area from which the specimen is to be extracted. In adults, the specimen is usually taken from the hip or sternum (breastbone). When the patient is a child, the biopsy site is generally a vertebra or long bone in the leg.

In a bone marrow aspiration, a special needle, known as a University of Illinois needle, is inserted beneath the skin and rotated until it penetrates the cortex, or outer covering of the bone. It may hurt a little at first, but the most painful part is when the marrow is being aspirated (sucked out). At least half a teaspoon of marrow is sucked out of the bone by a syringe attached to the needle. If more marrow is needed, the needle is repositioned slightly, a new syringe is attached, and a second sample is taken. The samples are transferred from the syringes to slides and sent to a laboratory for analysis.

Bone marrow biopsy may be performed immediately before or after bone marrow aspiration. The procedure is performed with a special needle, which has a hollow core, much like a leather punch. In bone marrow biopsy, the needle is inserted, rotated to the right, then to the left, withdrawn, and reinserted at a different angle. This procedure is repeated until a small chip is separated from the bone marrow. The needle is again removed, and a piece of fine wire threaded through its tip transfers the specimen onto sterile gauze. The patient may feel discomfort or pressure when the needle is inserted and experience a brief, pulling sensation when the marrow is withdrawn. Unlike aspiration specimens, which are smeared, these samples contain bone marrow whose structure has not been disturbed or destroyed. Microscopic examination can show what material its cells contain and how they are alike or different from one another. The bone must be decalcified (a process which takes place overnight) before it can be properly stained and examined.

Preparation

The physician should be told of any medication the patient is using and any heart surgery that the patient has undergone.

Aftercare

After the needle is removed, the biopsy site will be covered with a clean, dry bandage. Pressure is applied to control bleeding. The patient's pulse, breathing, blood pressure, and temperature are monitored until they return to normal, and the patient may be instructed to lie on his back for half an hour before getting dressed.

The patient should be able to leave the clinic and resume normal activities immediately. Patients who have received a sedative often feel sleepy for the rest of the day; so driving, cooking, and other activities that require clear thinking and quick reactions should be avoided in that case.

The biopsy site should be kept covered and dry for several hours. Walking or prescribed pain medications usually ease any discomfort felt at the biopsy site, and ice can be used to reduce swelling.

A doctor should be notified if the patient:

• Feels severe pain more than 24 hours after the procedure
• Experiences persistent bleeding or notices more than a few drops of blood on the wound dressing
• Has a temperature above 101°F (38.3°C). Inflammation and pus at the biopsy site and other signs of infection should also be reported to a doctor without delay.

Risks

Bleeding and discomfort often occur at the biopsy site. Infection and hematoma may also develop. In rare instances, the heart or a major blood vessel is pierced when marrow is extracted from the sternum during bone marrow biopsy. This can lead to severe hemorrhage.

Normal results

Healthy adult bone marrow contains yellow fat cells, connective tissue, and red marrow that produces blood. The bone marrow of a healthy infant is primarily red, with a limited ability to make blood.

Abnormal results

Microscopic examination of bone marrow can reveal granulomas, myelofibrosis, lymphomas, or other cancers. Analyzing specimens can help doctors diagnose iron deficiency, vitamin B₁₂deficiency, and folate deficiency, as well as anemia and leukemia.

Obesity can affect the ease with which a bone marrow biopsy can be done, and the results of either procedure can be affected if the patient has had radiation therapy at the biopsy site.

Key Terms

Aspiration

A procedure to withdraw fluid from the body.

Connective tissue

Material that links one part of the body with another.

Fibrosis

A condition characterized by the presence of scar tissue or fiber-containing tissues that replace normal tissues.

Hematologist

A medical specialist who treats diseases and disorders of the blood and blood-forming organs.

Hematoma

Blood that collects under the skin and causes swelling.

Hemorrhage

Heavy bleeding.

Myeloma

A tumor that originates in bone marrow and usually spreads to more than one bone.

Nurse practitioner

A registered nurse who is qualified to perform some specialized duties.

Vertebra

A bone that is part of the spinal column.

Further Reading

For Your Information

Books

• The Yale University Patient's Guide to Medical Tests, edited by Barry L. Zaret, et al. Boston, MA: Houghton Mifflin Company, 1997.

  Organizations

• Leukemia Society of America. 600 Third Avenue, New York, NY 10016. (800) 955-4572. http://www.leukemia.org.
• National Cancer Institute Cancer Information Service. 9000 Rockville Pike, Bethesda, MD 20892. (800) 422-6237.
• National Marrow Donor Program. 3433 Broadway Street NE, #400, Minneapolis, MN 55413. (800) 627-7692. http://www.atc.olivetti.com/red-cross/lance/nmdp.htm.
• The Wellness Community, 2716 Ocean Park Boulevard, #1040, Santa Monica, CA 90405-5211. (310) 314-2555.

  Other

• Bone Marrow Biopsy. http://home.cyberave.com/(hsquare/ndfiles/nd1506.htm.
• CanCareUSA Bone Marrow Biopsy. http://www.health.sa.gov.au/cancare/TREATS/TESTS/bmbiop.htm.

Gale Encyclopedia of Medicine. Gale Research, 1999.