How is bone marrow aspiration done?

Bone marrow is usually aspirated from the sternum or iliac crest in adults. Most patients need no more preparation that a careful explanation of the procedure, but for some very anxious patients, meperidine (Demerol) or an antianxiety medication may be useful.

First, the skin area is cleansed as for any minor surgery. Then a small area is anesthetized with lidocaine (Xylocaine) through the skin and subcutaneous tissue to the periosteum of the bone. The bone marrow needle is introduced with a stylet in place. When the needle is felt to go through the outer cortex of bone and enter the marrow cavity, the stylet is removed, a syringe is attached, and a small volume (o.5ml) of blood and marrow is aspirated. The actual aspiration always causes brief pain, so the patient is warned about this. Taking deep breaths or using relaxation techniques often helps.

If a bone marrow biopsy is necessary, it is best performed after the aspiration and with a special needle. Several types of needles are available, the procedure varying according to the type of needle used. Because these needles are large, the skin is punctured first with a surgical blade [no. 9 or 11] to make a 3 or 4 mm incision.

Only the iliac bone is used for this procedure, because the sternum is too thin.

The major hazard of these procedures is a slight risk of hemorrhage. This risk is increased if the patient’s platelet count is low; therefore a platelet count is obtained before the procedure. After bone marrow aspiration, pressure is applied to the site for several minutes. After a biopsy, pressure is applied to the posterior iliac crest for 60 minutes by the combination of a pressure dressing and having the patient lie recumbent in bed. Most patients have no discomfort after a bone marrow aspiration, but the site of a biopsy may ache for a day or two.