What happens during the bone marrow biopsy procedure?

What is involved in a bone marrow examination? What is a bone marrow aspiration? What is a core bone marrow biopsy? What tools are used in the procedure? So what you can expect on the day you get a bone marrow biopsy is generally you would, speaking very broadly, you would come to clinic, you would check in, you would be roomed in a clinic room, and then your provider like myself would join you in the room and go over the consent for the bone marrow biopsy. You can have a family member join you for support. We'll have a tech from our lab join us in the room to help process the tissue as we get it for the pathologist. We're doing this test, this is the definitive test to evaluate the health and function of the bone marrow or the blood making system. And so in order to do this we have to sample the bone marrow with a needle. We numb the skin and the bone of the posterior iliac crest, which is on the back of the pelvis. So when a patient has this done it feels like the back, but it's really the back of the hip bones or the pelvis bones on either side of the sacrum. And so we numb the whole area with lidocaine and then we use a needle to get an aspirate, which is a liquid portion of bone marrow that looks like a blood draw. And we can tell the difference between peripheral blood and bone marrow because there are bony and fatty elements in the bone marrow that tell us we're in the right spot. And then the second needle gets a core biopsy of the bone, which is similar to like those ice cores that you see in Antarctica where they can tell the different stages of the climate change. So we get, it's about a millimeter in diameter and about a centimeter in length. And it goes from the surface of the bone into the bone marrow so the pathologist can look at that bony matrix where all of those cells are made. And with the aspirate and the bony core biopsy the pathologist can tell us about the health of the bone, any malignant process in the bone, and it helps us make decisions about treatment. When we're getting the aspirate, usually a patient feels some pressure because lidocaine takes away the sensation of sharp pain but not pressure or temperature. So if you numb someone's whole arm with lidocaine and dump cold water on it, you could still feel cold water. So it's important for a patient to know that there are some sensations in bone marrow biopsy, but there shouldn't be a lot of pain. That's our goal, is to have it as pain free as possible, but you will have some sensation. So as we get the aspirate, sometimes there can be a feeling of intense pressure in the bone as we pull that liquid aspirate out, but that part is very quick. So usually we can manage that with some deep breathing exercises that we coach the patient through. And then to get the core biopsy, usually patients feel some pressure during that part, but there's less of that intense pressure change because we're not getting the aspirate anymore. And then from start to finish, the biopsy usually takes about 10 minutes, 12 minutes, maybe max, from the first numbing poke to the very end. Sometimes when we get into the bone marrow, it's more difficult to collect the samples and it takes a little longer, but I would say on average that's pretty fair for the amount of time a patient can expect. If you were to get this with conscious sedation, so you weren't awake for it, kind of like a colonoscopy, it would be the exact same procedure I discussed except at our facility that's done in interventional radiology. Sometimes they use a CT scanner to find the correct spot in the bone. And then to address your third question, they do use what we call a needle driver. And so this is an electric tool that helps drive a needle kind of similar to our hand tools, but it's on the end of the driver. And this tool can help speed up the procedure, but our pathologists don't see a major difference between the quality of the samples we get with the hand tools and the needle driver. So in the outpatient clinic, if you're not doing this sedated, you can expect your provider to use the hand tools. But at some centers and maybe in the future here, patients may have a bone marrow biopsy with that electric needle driver. So it's difficult because I think patients get used to what they're used to with bone marrow biopsies. They start to know what to expect. They kind of get a comfort level with the discomfort. They know exactly what to expect, how much sensation they'll have and how to get through it. So both the electric driver and the hand tools, I primarily use the hand tools. I would say with the electric driver, the procedure can be done a little more quickly. And the length of the core is usually a little bit longer, so that's better for the pathologist. But the process of procuring the core is actually a little more intense. It requires a little bit more force, but it's much quicker. So there are tradeoffs. Basically, I think it goes quicker, but you have a little more intense sensation during the procedure. So as of right now, we don't offer one or the other. We use primarily the hand tools in the outpatient clinic. But if you go center to center, each center is different. So at Seattle, they'll do something different. At Stanford, they'll do something different. So any cancer center you go to, it's just kind of what their providers or nurses who do the procedures are using at any given time. What is a bony core? So there's two major layers of the bone. So there's the outer thick covering called the cortex, and that's made up of the cortex and the periosteum, so that strong outer covering the bone. And the medullary cavity is that lacy, reticular bony structure where the bone marrow actually lives and our blood cells are made. And so you get that whole cross section with the bony core from the surface into the middle so the pathologist can look at the health of the bone itself. Are both the aspirate and core biopsy used by the pathologist? So everything from that sample is used. The cortex is not as important. So what they really want to see is the medullary cavity, the bone marrow itself. So from the liquid bone marrow, we make slides for the pathologist, and then we preserve some of that liquid bone marrow in anticoagulants, either EDTA or heparin, and then different tests can be run on that. So genetic tests and flow cytometry tests, basically like cell phenotyping tests can be run on that. And then the core biopsy itself, slides are made from the bone, and then the bone is processed and decalcified, and that can also be evaluated in the microscope. And then the last portion is we make a clot from the liquid bone marrow, and that can be frozen and sectioned and looked at under a microscope as well. So everything we collect is used to help us make a diagnosis about what's going on in the bone marrow itself.