The Blind Leading the Blind: Bone Marrow Aspiration Volume?
Recently on the blog site of a company that sells a bone marrow concentrator machine, a rather bizarre post appeared suggesting that patients should seek doctors who used a bone marrow aspiration volume that was published in the research. Confused? You’re not the only one, as I wasn’t sure what the point was either other than it provided a great opportunity to take a look in depth at the science of bone marrow aspiration. In addition, it also provides a demonstration of what I call the “blind leading the blind” and why your doctor is probably doing a BMA wrong.
First, a bone marrow aspiration is what allows the doctor to harvest stem cells from the back of the hip. The doctor numbs the area thoroughly and then uses a stiff needle called a trocar to extract what looks like thick blood from the bone. Most patients and many physicians conceptualize bone as having the consistency of cement, when in fact it’s more like hard plastic. Hence the right type of needle can easily be worked through bone into the space containing the stem cells. Our data collected way back in 2009 shows that about 9 in 10 of our patients thought that this bone marrow harvest procedure was no big deal.
The reason why the machine manufacturer blog post was silly is that the total volume of bone marrow to be taken, like anything else, depends on the dose of stem cells needed. Meaning more should be taken if more stem cells are needed and less if less are needed. This volume also should be adjusted by age, since fewer stem cells are found in the bone marrow of older patients. The single biggest mistake we see novice physicians make is taking a rather large volume (like 60 ml) from a single site. Why? Anything more than about 5-15 ml taken from a single site will mean that fewer stem cells are harvested. We’ve actually known that smaller volumes taken from many sites is better than a larger volume taken from a single site, going all the way back to the late 90s. Newer studies have confirmed the same thing. Our own internal research has also confirmed this many times. Despite this, colleagues who have taken courses sponsored by bone marrow machine manufacturers seem confused when I tell them that their technique of taking a large volume from a single site is reducing the number of stem cells for their patient. Based on the physicians I’ve spoken to, regrettably most are using this high volume=low stem cell numbers technique.
Another big problem we see out there in the stem cell wild west is that the doctors using automated bone marrow concentrators are truly flying blind when it comes to yield. This means that the machines don’t count the cell numbers obtained, so the doctors have no feedback on whether a lot of cells was obtained or very few. Think about this for a second, the research above shows that the doctor’s technique is a big factor in whether the patient will have enough stem cells harvested. Yet the doctor has no idea how many cells he got, because the machine he bought from the sales rep has no way to count them. This is a bit like a blind man learning to hit a baseball. As you might imagine, even if he hits the ball, without someone telling him how far and in which direction it went, he could never hone his skills to get the ball to go where he wanted. While every Regenexx provider has always had the ability to count the number of cells in the sample to maximize the yield, 99% of the other physicians don’t have that ability and therefore are a bit like the blind man playing baseball. This is also critically important, as our registry data shows that for knee arthritis, getting past a minimal cell dose is critical for success.
Finally, imagine driving your car with thick black paint on the windshield. You would surely crash in seconds! Despite that vivid description, this is what many physicians who have taken these courses sponsored by machine manufacturers are doing. By this I mean that they don’t use imaging guidance (ultrasound or fluoroscopy), to ensure that the needle to take stem cells is in the right place. Not only does this impact the average doctor doing the procedure, but, more concerning is that it impacts the research that we physicians rely on. Take for example both studies above; they both were without imaging guidance. The second more recent paper by stem cell pioneer Phillpe Hernigou is predicated on the concept that exactly 2 cm was used between each draw site on the pelvis, yet describes no use of x-ray guidance (fluoroscopy) that would have been critical to ensure that the needles were placed at that distance. This could seriously impact some of the study results (the good news for this particular study is that it’s unlikely to change the main findings).
The upshot? It’s the blind leading the blind right now. As a result of what’s taught in courses sponsored by machine manufacturers and an inability to have real time feedback on cell yields or even where the needle was placed, most physicians aren’t maximizing the stem cell yields from patient BMAs. This is unfortunate, as patients pay out of pocket for these procedures and should be upset if the draw isn’t performed properly. How can you make sure that you’re getting what you paid for? Look for these three things:
1. The doctor draws from multiple sites on each side
2. The doctor has the ability to count the cells he gets
3. The doctor places the needle to draw cells under fluoroscopic or ultrasound guidance