Neurosurgery: Arteriovenous Malformations
Guest: Dr. Raymond Turner – Neurosciences, MUSC
Host: Dr. Linda Austin – Psychiatry, MUSC
Dr. Linda Austin: I’m Dr. Linda Austin, interviewing Dr. Raymond Turner, who is an instructor in the Department of Neurosurgery and Radiology here at the Medical University of South Carolina. Dr. Turner, in this podcast, let’s talk about something called AVM, or arteriovenous malformation. Just what is that?
Dr. Raymond Turner: An arteriovenous malformation, or an AVM, is a short circuit between arteries and veins. Arteries are the blood vessels that bring blood to the brain. Veins are the blood vessels that take blood away from the brain. Normally, there’s a filter between the arteries and the brains, called capillaries, and that’s how the brain is able to get its oxygen and nutrients. When an AVM develops, it’s usually a developmental problem. So, people are born with AVMs, and they come in all sorts of shapes and sizes. But, generally speaking, it’s a short circuit, or disconnect, so the arteries feed directly into the brain.
Dr. Linda Austin: I’m trying to picture this. I’m imagining, for example, a city where you have one super highway that goes in and then it breaks up into all sorts of little side streets, and then they come back together and there’s another super highway that goes out, and all those little neighborhoods sort of keep the blood pressure down, and then it goes back into the exit highway in an orderly way. But, it sounds like, with an AVM, it’s as if there’s a direct side street that goes right from one super highway to the one going in the opposite direction. Just like you’re not supposed to make a U-turn on the freeway, it sounds like this is not a good thing.
Dr. Raymond Turner: That’s exactly right. It’s, essentially, like you described, a freeway system with no exits, so we can’t go to the side streets. Typically, when we look at an AVM on the brain, grossly, it looks like, actually, a bag of worms. It’s a tangled mesh of blood vessels. There’s no functioning brain in between these blood vessels.
Dr. Linda Austin: Why does that cause problems?
Dr. Raymond Turner: They generally don’t cause problems. This is a very rare condition, and oftentimes it’s a condition that doesn’t have many symptoms. The symptoms that this can cause include headaches, seizures, or stroke. When they bleed, they can cause a stroke. Generally speaking, this isn’t a devastating stroke that’s going to kill you immediately, fortunately. So, we’re able to, then, identify that the patient has a problem; that they have an arteriovenous malformation, and then we can formulate a treatment plan.
Dr. Linda Austin: I see. Now, am I right in thinking that an AVM can happen anywhere in the body; not just, necessarily, in the brain, but it’s, obviously, extra devastating if it’s in the brain, as opposed to in your big toe?
Dr. Raymond Turner: That’s correct. They can happen anywhere in the body. And, here at MUSC, we’re fortunate to have experts that specialize in AVMs of both the brain and the spine.
Dr. Linda Austin: So, a patient might become first aware of an AVM, how? How would they even know that they have this?
Dr. Raymond Turner: They probably wouldn’t it, unless it was giving them problems, such as having a seizure, having bad headaches, which would lead them to getting an imaging study that would then find that they have an AVM.
Dr. Linda Austin: And, how do you go about treating it then, once you’ve discovered it?
Dr. Raymond Turner: Well, once we’ve discovered it, the first thing we have to ask is: Should we treat it; do we need to treat it? Some AVMs are located in a part of the brain that is not very surgically accessible. So, to treat it, would do more harm than good. However, fortunately, most AVMs are small enough and in area of the brain where they’re readily treatable. So, our option to treating an AVM is actually a threefold approach.
Our first option is to surgically cut out the AVM by making a small window in the bone of the skull, and then going into the brain and just taking out the AVM, leaving the normal brain behind. The second option is to treat the AVM from within the blood vessels, essentially gluing it off so blood can’t flow through it anymore. And then the third option is to do radiosurgery, such as gamma knife. Now, oftentimes, we end up doing a combined approach. We would do endovascular; gluing off of the AVM, followed by surgical resection, to get a definitive cure. Or, we would embolize it through the blood vessel and then radiate it with stereotactic radiosurgery.
Dr. Linda Austin: So, let’s go into some of those terms a little bit more. When you say gluing it, I’m kind of picturing a big glob of glue.
Dr. Raymond Turner: That’s essentially correct. We’re going up there with very small catheters, very deep into the brain, right to the AVM. And, through that catheter, there are several substances that we can use to effectively glue off the blood vessel that’s feeding the AVM, but sparing the rest of the brain.
Dr. Linda Austin: And, you mentioned embolization, what is that?
Dr. Raymond Turner: Embolization is blocking off the blood vessel, or gluing off the blood vessel.
Dr. Linda Austin: I see. Putting some kind of plug into it? Is that right?
Dr. Raymond Turner: That’s exactly right. So, when we’re operating on an AVM, one way to think about is, if you’re going to do plumbing in your house, you’re going to shut the water off to the pipes before you start taking them apart. AVMs are very similar. If we were to occlude the blood vessels going to the AVM…
Dr. Linda Austin: Or, block.
Dr. Raymond Turner: Or, block them off, making surgery on them that much safer and easier.
Dr. Linda Austin: How long does this procedure take, generally?
Dr. Raymond Turner: Depending on where the AVM is located, surgery on the AVM can take anywhere from two to four hours, if we’re to do open surgery to cut it out. When we’re talking about blocking off the AVM, through embolization, we, generally, will do that over several sessions, each session taking anywhere from two to four hours. After each of those sessions, the patient will stay in the hospital overnight; for a day, and often go home the next day. And they feel back to their usual self within another day or so. When we do radiosurgery for an AVM, it’s typically half a day of treatment in the hospital, and you go home that night. So, it’s effectively a same-day surgery. You feel a little bit tired the evening of the radiosurgery but, otherwise, you’ll be back to normal the next day.
Dr. Linda Austin: You make it sound easy.
Dr. Raymond Turner: Things always sound easier than in reality.
Dr. Linda Austin: It’s like people watching a painter paint a beautiful painting. Yes, maybe they can do it in two hours, but it took them 20 years to learn how to do it.
Dr. Raymond Turner: That’s exactly right. The one downside of doing radiation to the AVM is that the effect isn’t immediate. When we surgically operate on the AVM, or embolize it, we see results immediately. However, when we do gamma knife on an AVM, we may not see that AVM disappear for 18 month to three years, after the treatment. So, during that time, the patient has to live with the risk of that AVM giving them problems during that time period.
Dr. Linda Austin: And I’m sure some people find it easier to live with that risk than others.
Dr. Raymond Turner: That’s exactly right. I see a lot of people with problems of the brain. And, generally speaking, there are three types of people that come into my office with a problem of the brain. One person is very thoughtful about what’s going on and wants to have the best thing done, and they’ll have treatment if that’s indicated. There’s the person the person that comes in who hasn’t eaten for six hours and just wants to lay there on the table, right then and there, and have the surgery; an operation, because they can’t tolerate having something in their head. Then there’s the patient that comes in, and it doesn’t matter how devastating their problem is, nobody’s going to be operating on their head. And those are the most difficult patients, if they have serious problems, in terms of getting them to understand what they’re risks are.
Dr. Linda Austin: Dr. Turner, we’re so glad to have you here at MUSC. We welcome you. This sounds like very important work that you’re doing.
Dr. Raymond Turner: Thank you very much, Dr. Austin.
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