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BONE MARROW ASPIRATION

Why is Bone Marrow Aspiration being performed ?

Bone marrow aspiration means taking a sample of bone marrow by inserting a needle through the bone under anaesthetic and sucking a small amount of marrow into a syringe. The bone marrow is the place where the cells of the blood are produced. The commonest reason for looking at the bone marrow is to find the cause of an abnormality in the blood, for example anaemia or a low white blood cell count. A bone marrow sample can also help in the diagnosis of certain infections, for example tuberculosis. In patients with certain types of cancer it is important to know whether there is any evidence of the cancer in the marrow as this may affect the type of treatment given. Some people have aspiration of their bone marrow so that it can be donated to a relative with a serious blood or other disorder. This is a more complicated procedure and is not dealt with in this section.

Preparations needed for Bone Marrow Aspiration

The procedure only takes about 15 minutes, and you should feel well enough to go home after a short rest. There are no special preparations but it is sensible to have something to eat and drink beforehand as you will be less likely to feel faint during the procedure. This is normally done under local anaesthetic and the doctor must be told about any allergies to previous local anaesthetics. In this case, a sedative would be used instead.

What Happens during Bone Marrow Aspiration

The bone marrow exists throughout the body in the cavities of the bones, but there are only a few places which are really convenient for taking bone marrow samples. The commonest place to be used is at the back of the pelvis. If hands are placed on the hips, the thumbs will be over the place where bone marrow is taken. Marrow can also be taken from the breast bone (sternum). The doctor will first examine you carefully to choose the most suitable site. Then the skin will be sterilized by wiping with special fluid. Local anaesthetic will be used to numb the skin and the surface of the bone. A strong needle is then pushed through the skin and the outer surface of the bone until the tip of the needle is in the marrow cavity. No pain should be felt: only some pressure as the needle is pushed into the bone. A syringe is then attached to the needle and a small sample of bone marrow sucked out into the syringe. This produces an uncomfortable sensation and sometimes feels painful. This is because the local anaesthetic cannot be injected into the bone marrow cavity. However, the discomfort only lasts a few seconds. The needle is then withdrawn and pressure applied to prevent bruising. A small dressing is then put on. In some cases a trephine sample will be required as well as an aspirate. This is a tiny core of bone. The trephine sample is taken with a different type of needle. It is done under the same local anaesthetic after the aspirate sample. The reason for taking a trephine in some cases is that it provides a larger sample of bone marrow and increases the chance of diagnosing certain disorders.

Possible Complications of Bone Marrow Aspiration

Bone marrow aspiration is a very safe procedure and complications are rare. Excessive bruising can occur, usually only if there is some abnormality of blood clotting. Infection of the site can also occur but is very unusual.

After Bone Marrow Aspiration

When the local anaesthetic wears off, there may be some discomfort at the site of the marrow aspiration. This will fade over the next day or so. Painkillers are not usually required but paracetamol may be useful. The dressing should be kept dry for 24 hours to allow a small scab to form. After 24 hours the dressing can be removed and one can bath as usual. There are no delayed effects of the procedure.

If Bone Marrow Aspiration is not performed

It would be difficult for the doctor to make the right diagnosis and so decide on the correct treatment for your problem.

Effects on Family of Bone Marrow Aspiration

It may be sensible to ask a family member or friend to come with you and take you home afterwards. However, you will usually be able to drive.