Bone Marrow Biopsy

General Description

A bone marrow biopsy involves the extraction and subsequent analysis of a bone marrow sample, the spongy tissue found inside most bones. Bone marrow contains stem cells that give rise to blood cells (white blood cells, red blood cells, and platelets), playing a crucial role in the immune system.

The biopsy is usually performed alongside a bone marrow aspiration, in what is known as a bone marrow study:

• In aspiration, a small amount of bone marrow fluid and cells are extracted.
• In biopsy, a portion of bone containing marrow is removed.

When is it indicated?

Bone marrow aspiration and biopsy are used to diagnose and characterize hematologic disorders suspected due to abnormal blood test results. These conditions include:

• Anemia.
• Blood or bone marrow cancers, such as leukemia, lymphoma, or multiple myeloma.
• Bone marrow metastasis from cancer originating in another area.
• Viral, bacterial, or fungal infections.
• Hemochromatosis.
• Disorders involving abnormal blood cell production, such as leukopenia, leukocytosis, thrombocytopenia, thrombocytosis, or polycythemia vera, among others.

Additionally, a bone marrow study is used to stage a disease or monitor the effectiveness of its treatment. It is also the procedure used to extract bone marrow for transplantation.

How is it performed?

In both procedures, aspiration and biopsy, the sample is typically taken from the iliac crest, the upper edge of the back part of the hip bone. Occasionally, aspiration is performed at the front part of the pelvic bone or the sternum, and in children under 18 months, in the bones of the lower leg.

Generally, bone marrow aspiration is performed first. A small incision is made, and an aspiration needle is inserted until it reaches the marrow, where a sample of the fluid is extracted by suction. Several samples may be needed, sometimes from both sides of the hip.

For the bone marrow biopsy, a trocar—a tool consisting of a thick needle and a cannula—is used. The trocar is inserted deeper into the bone using pressure and rotation to obtain a cylindrical sample of marrow tissue.

Risks

Both aspiration and biopsy are safe procedures that rarely present complications. Possible issues include:

• Excessive bleeding: the risk is higher in people with clotting disorders or low platelet counts.
• Infection in the skin or bone: may occur in individuals with compromised immune systems.
• Cardiac or lung injuries caused by needle penetration in aspirations performed at the sternum.

What to expect from a bone marrow biopsy

This is an outpatient procedure that does not require hospitalization. Before starting, the patient’s blood pressure and heart rate are measured, and a sedative may be administered to help with relaxation. The procedure is performed with the patient lying face down, on their side, or face up, depending on which bone is used for the sample. The body is covered with a drape, leaving only the puncture site exposed. That area is sterilized and injected with a local anesthetic.

During needle or trocar insertion, the patient must remain very still. It is normal to feel pressure as the needle is inserted, as well as a pulling or dragging sensation, and even pain, while the sample is aspirated and extracted. During the biopsy, it is common to feel more pressure and a twisting sensation as the trocar is inserted and removed. A cracking sound may also be heard. The entire procedure takes about 20 to 30 minutes.

Once the samples are taken, pressure is applied to the area for about 15 minutes to stop bleeding, and a small dressing or bandage is placed. It is common to feel slightly dizzy and experience leg numbness for a few minutes, so the patient should remain lying down on the examination table. If intravenous sedation was given, the patient must stay in the recovery area until the effects wear off. If only local anesthesia was used, they may leave once the bleeding has stopped. At home, the dressing should be kept dry for 24 hours, and rest for a few hours is recommended. The area may feel stiff or sore for a few days.

Specialties that request a bone marrow biopsy

Both bone marrow aspiration and biopsy are commonly requested in hematology and oncology consultations.