An iliac crest bone marrow aspiration is a procedure to collect a liquid sample of the soft, spongy tissue inside your bones. This marrow is the body’s factory for producing blood cells, including red cells, white cells, and platelets. To assess the health of this tissue, a sample is taken from the posterior iliac crest, the back of the hip bone. This site is used because it is a large bone located away from major organs, making the procedure safe and accessible.
Reasons for a Bone Marrow Aspiration
A bone marrow aspiration is performed for several diagnostic and monitoring purposes. It allows physicians to investigate the cause of abnormal blood cell counts, such as anemia (low red blood cells), leukopenia (low white blood cells), or thrombocytopenia (low platelets). The procedure is a primary tool for diagnosing and staging blood cancers like leukemia, multiple myeloma, and lymphoma. By examining the marrow, doctors can identify cancerous cells and determine the extent of the disease.
Beyond initial diagnosis, this procedure is also used to monitor the progression of a known disease or to evaluate the effectiveness of treatment. For patients undergoing chemotherapy, a bone marrow sample can show how well the treatment is suppressing cancer cells and if the healthy marrow is recovering. It can also be used to investigate fevers of unknown origin, as certain infections can affect the bone marrow.
The Procedure Step by Step
Before the procedure, your healthcare provider will discuss your medical history and any medications you are taking, particularly blood thinners, which may need to be paused. Sedation may be offered in addition to a local anesthetic to ensure comfort. For the procedure, which takes about 20 to 30 minutes, you will be asked to lie on your side or stomach to provide access to the posterior iliac crest.
Once you are positioned, a healthcare provider will clean the skin over the hip with an antiseptic. They will then inject a local anesthetic into the skin and down to the surface of the bone, which will numb the area. You may feel a stinging sensation from the numbing medicine, but this quickly subsides. The provider then makes a very small incision and inserts a hollow needle through the skin and into the bone. While the bone itself cannot be numbed, the anesthetic helps manage discomfort.
With the needle in place, a syringe is attached to perform the aspiration. You will likely feel a sensation of pressure and a brief, but sometimes sharp, pulling or aching feeling as the liquid marrow is drawn into the syringe. This part is very quick, usually lasting only a few seconds. In most cases, a bone marrow biopsy is performed immediately after to collect a solid core of the marrow tissue. After the samples are collected, the needle is removed, pressure is applied to the site to stop bleeding, and a bandage is placed over the area.
Recovery and Aftercare
Immediately following the procedure, you will be monitored for a short period to ensure there are no complications. If you received sedation, you will need someone to drive you home and should plan to rest for the remainder of the day. It is common to experience some soreness or aching at the hip for a few days, which can be managed with over-the-counter pain relievers like acetaminophen.
At-home care involves keeping the bandage clean and dry for at least 24 hours. After this period, you can remove the bandage and shower. It’s recommended to avoid strenuous physical activity or heavy lifting for a day or two to allow the site to heal properly. While complications are rare, it is important to watch for signs of infection, such as increased redness, swelling, persistent pain, or any significant bleeding from the site.
What the Bone Marrow Sample Reveals
Once collected, the bone marrow aspirate and biopsy samples are sent to a laboratory where a pathologist, a doctor specializing in diagnosing diseases through tissue examination, performs a detailed analysis. The pathologist first examines the sample’s cellularity, which refers to the quantity of blood-forming cells in relation to fat cells within the marrow. A healthy balance changes with age, and deviations can suggest either an underactive or overactive marrow.
The analysis also involves a microscopic review of the different types of blood cells present. The pathologist assesses the number, size, and maturation stage of red blood cells, white blood cells, and platelets to determine if the cells are developing correctly. The presence of abnormal cells, such as leukemic blasts or cancerous plasma cells, can be identified, leading to a specific diagnosis. The structure of the biopsy core also provides information about the overall architecture of the bone marrow.