William Mack, MD, a neurosurgeon at Keck Medicine of USC, discusses minimally invasive neuroendovascular and open microsurgical approaches to the management of cerebrovascular disease. He also addresses the manner in which laboratory studies can be leveraged to answer questions generated in clinical medicine and advance patient care.
Yeah. Hello. My name is William Mac. I'm a professor of neurosurgery at KEK Medical Center of U. S. C. And today I'm going to speak about vascular and endovascular neurosurgery. Specifically, I'm gonna talk about some advances in both patient care and laboratory science. So to begin with, the field of vascular and endovascular neurosurgery is very exciting. And there's been a lot of movement in the last 10 or 20 years. Here is shown a picture of a minimally invasive operating room called the Angiography suite, where catheters air steered through the blood vessels to treat blood vessel disorders. This is a minimally invasive way of treating vascular disorders, and a lot of what I'm gonna speak about today. Likewise, across the street, we have a laboratory in the silken neuro genetic Institute, where we look at the mechanisms of inflammation in cerebral vascular disease, stroke low blood flow to the brain, and we try and tie these findings into what we see in the clinic in the operating rooms. First, I'll start to talk about stroke. This is a big part of our practice. Stroke is the third leading cause of death and the leading cause of disability in the world. Billions of dollars are spent on stroke annually in the United States. As you can see from the picture, ischemic stroke is a blockage in one of the blood vessels in the brain where not enough oxygen gets to the brain tissue. We see patients with stroke all the time. This patient that I'm showing here is a 64 year, 65 year old woman who presented, unable to speak and with right sided weakness. As the pictures show, she has a blockage in the artery in the left side of her brain. This is causing a very small esque emmick stroke in the left hand picture on the purple and a large area of low blood flow to the brain that could be saved or salvaged by our procedure. The procedure we used to try and salvage this tissue is called mechanical thrum Back to me. That's putting a device up through the blood vessels into the brain and removing the clot in a minimally invasive fashion through a needle stick in the leg. There's multiple different devices that could be used for this procedure, and this slide doesn't even show all of them There's been an evolution from the left to the right side, starting with ah corkscrew like device that is able to extract the clot from the blood vessels. Moving Toe Aspiration Systems, which construction the blood clot out of the vessels and what we call stent retrievers, which are stents on a wire that could be used to engage the clot in the blood vessel and then pull it out down through the access in the leg. In this patient that I showed. This is the angiogram that that was performed when we shot pictures of the blood vessels of the brain. This was a 79 year old woman unable to speak or move her right side. When we put one of our stent retriever devices up through our minimally invasive incision in the groin, we can see flow to the left middle cerebral artery that we didn't see on the previous pictures. This stent allows the contrast or blood to flow through, and the and the brain to get oxygenation through the bloodstream. Once the stent is removed, there's no longer a narrowing in the blood vessel, and the brain is perf used, so this patient went from having no blood flow in the left middle cerebral artery territory or the left side of her brain to having complete blood vessel complete blood flow in that area of the brain. These patients who have this procedure often return a substantial amount of their neurological function, depending on when the procedure is done. Another disease that we focus on his carotid artery disease or stenosis. Rather than being a large stroke. This is a narrowing in the blood vessel in the neck, which can cause a stroke. It can cause a stroke, either by a small piece of plaque coming off the neck, blood vessel and lodging in the brain as I showed before. Or do the low blood flow to the brain from the narrowing. This is responsible for about 20% of strokes from this decrease in blood flow. The procedure we use for this in the operating room is a carotid endarterectomy. This is where we make a small incision in the neck, and we open up the carotid as seen in the right hand side of the picture, and remove the plaque that was in the carotid artery, and so it back up. So there's good blood flow through the blood vessel. This procedure has been done for a long time and is a very good procedure to clean out the blood vessel. There have been newer procedures through the minimally invasive routes that I talked about in the groin or leg blood vessel, where we can steer our catheters up through the blood vessels and put a stent into the carotid artery rather than removing the plaque. What we do in those procedures is use a balloon to dilate the plaque in the carotid artery and then place a stent in the artery to keep it open. This slide shows a number of the different stents. They have different designs and shapes based on the connections of the metal. They're either open or closed cell with mawr room or less room between the connections of the night and all, or the metal and the stent to protect from the from the plaque dislodging during the procedure. Along with these stents, we deploy em bolic protection devices or often filters. You can see pictures of these. These air pushed past the plaque and opened up to catch any debris that may go north towards the brain. When we're opening the blood vessel in the neck, I'll show you a picture of this. This next picture shows a patient that had radiation to their neck and surgery previously, so they were not a good candidate for the open carotid endarterectomy procedure. We did a carotid artery stent on this patient. You can see in the left hand picture. There's an extreme narrowing in the blood vessel, along with an irregularity. This patient was not getting enough blood flow to the brain through this blood vessel in the middle picture, we've already used our balloon and replacing the stent where the arrow is, and in the far right picture the stent is placed. You can see that not only is the blood vessel opened, but it's much more regular. If you look at the top of the picture, you can see the filter device placed, which is up at the top of the artery that was being treated in order to catch any plaque or debris that would happen to be removed during the procedure and go up the bloodstream. Cerebral aneurysms are a problem that we see frequently these air Dilip ations of the blood of ah section of the blood vessel, forming a type of balloon in the blood vessel, which is prone to rupturing or popping. These often don't give patients any problems until they rupture, but once they do, they become a serious threat to their health. Here is a picture of a 45 year old man who presents with presented with a ruptured brain aneurysm, and this shows are clipping technique where we open a small piece of bone on the side of the skull, were able to split the lobes of the brain off to the side and get into where the blood vessels are and put a little metal pinch clamp or clip around the aneurysm so that blood flow no longer flows into it. Alternatively, we can use our minimally invasive endovascular techniques and treat these aneurysms from the inside with what we call coils. These air a list of prior coil shapes and sizes and show the evolution from the beginning standard coils to different shapes and configurations that we're able to deploy through our catheters into the aneurysm. These pack the aneurysm from the inside here's of a Cares, a case of a 52 year old with an irregular aneurysm at the top of the carotid artery. You can see that on the picture on the left that demonstrates the filling of the sack at the top of the of the artery on the right. You see that that blood filled sack packed with coils no longer having any blood flow go into it. So this is an aneurysm treated with coils. If the neck of the aneurysm is wider and the coils won't stay in, we can use other devices, such a stents or balloons to assist keeping the coils in these aneurysms. More recently, some newer devices have gone on to the market to treat brain aneurysms. The first type of treatment is called flow diversion, and this is where we put a stent that has mawr dense braids than many of the other stents that we use into the blood vessel in order to have the blood flow go through the blood vessel but not into the aneurysm. This basically excludes the blood flow from the aneurysm, and the aneurysm clots and thrombosis is over time. Several different trials have shown the efficacy of these flow diverting stents, and there's several different brands on the market. Here's a case of a 70 year old man you can see on the left. He had a very large right internal carotid artery aneurysm that was just below the level of the I. He had some double vision as this was compressing one of the nerves in the middle. You can see an X ray. We put in to flow, diverting stents. We telescope them together to treat the aneurysm. At six months, we shot another angiogram, which is shown on the right hand side of the screen, and there's absolutely no filling of the aneurysm left. So this aneurysm was cured by these flow diverting stents without even putting anything into the aneurysm. Even more recently, interest tacular flow diverting devices have come onto the market these air devices that we can place in the aneurysm and they divert the flow away from the aneurysm. The benefit to these devices are we don't put anything in the patient's parent vessel. When we do put things stents in the patient's parent vessel, we have to have them on dual anti platelets, which are a type of blood thinning agent or anti platelet agent. With these new devices. We don't have to use dual anti platelet agents with our treatment, so it makes the patient more comfortable and less apt to bleed it. Yeah, here's an illustration. This was a 54 year old woman who presented with an aneurysm that had not ruptured. She presented with dizziness and found this aneurysm on an Marie. This is at the top of the basilar artery or the basilar apex. The middle picture here shows the woven Endo bridge or Web device being deployed into the aneurysm that you see on the left. And on the right side. You see a follow up picture from six months later that shows absolutely no filling in the aneurysm. The aneurysm has completely thrombosis and clotted off. I'm going to switch gears now from the endovascular sweet to the operating room, where we've also been using minimally invasive techniques to do surgical procedures. Here you see an interest cerebral hemorrhage, which is a blood clot in the brain, pushing the tissue aside and causing neurological dysfunction. We used to do these when we operated on him through very large craniotomy, Zor incisions in the bone in the skull. Now we're able to use a port or a small tube to do the procedure through a very small quarter sized, um, removal of the bone and skin tissue above the level of the blood clot. Yeah. Here you see a picture of the entire skin opening and bone opening that has to happen to get this small tube in to respect a deep hematoma or blood clot within the brain tissue. This is the patient's cat scan. On the top, you see the hyper density or white in the right side of the brain, which is the blood clot causing compression and neurological dysfunction in the bottom. You see a scan after we did our minimally invasive port assisted procedure, where almost all of the blood clot has gone and the brain has gone back to a relaxed, unsheathed ID position. This was all done through that quarter sized incision that I showed. Importantly, I mentioned at the beginning of this talk that we have an extensive laboratory effort where we mimic the and and study the surgical considerations that we've seen in the operating room and in the angiography suite, and we model them in the laboratory. This allows us to ask questions in the clinic and the operating room. Bring them to the laboratory model. These very questions come up with answers, solutions and translate them back to the clinic. The first model that we had that we had adapted is a middle cerebral Artery stroke model, which mimics the first case that I showed you, Ah, large blockage in an artery of a patient who presents with a stroke. In this, we're able to study inflammation. Look at the cells that are involved in the stroke. Look at the time course that that occurs with and hopefully design therapies. Thio, treat or reduce the burden of these strokes. More recently, we've developed or refined a model of carotid artery stenosis, such as the narrowing in the carotid artery that I showed earlier in the In this talk. This is a much more subtle, ah subtle insult in terms of ischemia, these animals. These mice do not have large strokes and are not affected in terms of their arm or their leg, but just have very subtle behavioral deficits that are somewhat similar to patients having difficulty balancing their checkbook are carrying out some of the everyday functions that they typically dio. In this case, we narrow the carotid arteries by about 70% and decreased blood flow to the brain. And, as you can see in our Doppler tracing on the top right when we put our first coil on, it doesn't lower the blood flow that much because of the collaterals in the brain. But when we put the second one on the other side, we get the effect that we're looking for. You see stains here that shows subtle white matter injury and behavioral tests. Working memory on the bottom left demonstrate subtle deficits in working memory. Most recently, we've been studying inflammation in the way of air pollution and particulate matter here in Los Angeles, in collaboration with our environmental engineers, they've collected particulate matter or air pollution from the 1 10 freeway region, and we've distilled it down to nanoparticles and exposed the mice to these air pollution or filtered air. And we've carried out our cerebral hypo profusion and stroke experiments. What we're seeing is that air pollution, or the particulate matter that composes it, does have a profound effect on the evolution of stroke and cerebral hippo profusion. In either case being exposed to the air pollution makes the insult the stroke or the low blood flow to the brain manifest as worse neurological injury than if a patient had not been exposed to air pollution. So this gives you an idea of some of the cutting edge procedures and techniques that we've been employing in the operating room and angiography suite and how we're trying to use the laboratory to model these and answer the questions that will help drive our patient care towards better outcomes. Thank you for your time.