Hi, I'm Dr Abhishek Gray with the Department of Neurosurgery at University Hospitals Cleveland Medical Center. Thank you for having me for the 2020 Stroke Conference and Neuroscience Nursing Symposium. I'm gonna talk about mechanical throwing back to me and the current treatment recommendations and also do a couple cases at the end as well. First, it's important to talk about the different stroke types for our purposes. Today, we're gonna be talking about ischemic stroke. Uh, there's also interesting girl hemorrhage and subarachnoid hemorrhage. And the presenting symptoms can be different from the with the three different types of strokes with the scheme IQ stroke, The focal neurologic deficit is often sudden. Onset, um happens right away, whereas with intra cerebral hemorrhage, it is usually more progressive over minutes, two hours and then with subarachnoid hemorrhage. Often there are no focal neurologic deficits. Headache is usually not present with the scheme IQ stroke, the exception being strokes in the posterior fossa or in the cerebellum, or that can cause headaches. Whereas with interesting girl hemorrhage, there is headache and subarachnoid hemorrhage. It's usually classified as the worst headache of your life. Um, depressed consciousness can happen within cerebral hemorrhage and with subarachnoid hemorrhage but usually does not happen with ischemic stroke and patient history is really important initially, uh um, to try to find out, you know, Are there any red flag signs that we need to be aware of? Was there any collapse or loss of consciousness Headache, worsening of neurologic deficits, seizure activity at onset, any anti thrombin attic or anti platelet therapy, previous stroke or brain surgery on g'quan, neuropathic disorders or things that cause, um, quadrille apathy such as general or liver failure of eligon, insee and diabetes? First things first. You know you always have to remember your A B CS and maintain oxygenation. Be alert to airway problems such as difficulty handling secretions or swallowing. Uh, this is especially true with patients with large vessel inclusions with high end I a stroke scale. Twenties. Um, early loss of airway and strokes can't suggest that this may be uninterested Abril hemorrhage rather than an ischemic stroke. Um, elevate the head to 30 degrees to prevent aspiration with nausea, vomiting in the left lateral recumbent position that can avoid that as well assessed for cardio respiratory tolerance of testing and treatment. You know Can this patient tolerate a CT scan laying flat? Oh, are even more time consuming an Emory or a neuro intervention without protecting the patient's airway or stabilizing the patient from a cardio respiratory standpoint? Hypertension. Something to note is usually not a sign of ischemic stroke. In fact, usually patients are hypertensive. We'll talk about this a little bit further with diabetes P A. But patients for Ivy T P A. Are eligible for with blood pressures less than than 1 85/1 10. And, um, sometimes we will have to give medications to bring their blood pressures down. So we that that patient can be eligible for T p A. However, you want to be careful about that because often times your blood is your blood pressure is a response to an area that's ischemic, and it's getting collateral circulation from other vascular territories. And and you need that blood pressure, Uh, for that, uh, area of the brain to not fully die so hyperglycemia can be a big mimic er of acute stroke. I've seen patients with hypoglycemia with ah, full on almost left M C A or right M C. A type picture where they have a cute weakness of both arms and legs of one side, Um, with very focal deficits. Um, communicate with a D physicians and nursing staff, the diagnosis and and what the plan of Care is. Review the the stroke scale with the nursing staff page, a stroke alert or a brain attack page. If the stroke is suspected to be less than 24 hours, if not already done here, here's some stroke mimics Ah, lot of patients with suspected stroke ends up not being a stroke at all, but one. Oftentimes, one of these other problems we'll, uh, talk about in this slide, uh, 10 to 30% of strokes in the E D and 50 to 70% of in house meaning patients that are already hospitalized. Um, who a brain attack pages called on really has something else going on, such as hypoglycemia as we talked about seizure toxin, encephalopathies, metabolic disorders, delirium or dementia sink API migraine complex migraine especially, or a spinal cord problem. Um uh or psychogenic. So when it comes to the acute stroke guidelines, I think before we talk about throwing back to me, we have to talk about Ivy t p A, which is a standard of care. And, um uh, the n i N D s study and then later e cast three expanded the window for intravenous tp a therapy for acute ischemic stroke. And, uh, now, this is standard of care for less than three hours and then even up to 4.5 hours, uh, for patients, for certain patients. As you can see, um, here's some of the different studies studying I've thrown valises. This slide shows that time is brain, and the impact of time to treatment is crucial. You can see that the odds ratio for a global good outcome, uh, dropped significantly at three hours from 90 minutes and then even more so a to 4.5 hour mark. Here is a visual aid to help kind of patients and families make a decision. Uh, sometimes and also kind of emphasizes how effective I v t p a is, um, over here for the under three hours window for every 100 patient eligible for I v t p. A. 32 benefited on Day three were harmed and the rest were unaffected for the 3 to 4.5 hour window. Again, it's a little less effective, but still very effective for every 100 patients. 16 benefit three were harmed and the rest unaffected to Here's some guidelines that are a little bit out to date, but basically, you know, we want a narrow expertise. Um uh, and a CT had done quickly, and I v t p A within 60 minutes. If there is a throwback to me that's going to be done, we'd like to get the intervention started with access growing access time at 90 minutes from door to groin, then transfer when indicated within two hours and stroke unit admission within three inclusion criteria for I v T p A. Therapy, um, you know is a diagnosis clinical diagnosis of acute ischemic stroke. Uh, there's a measurable, functionally impairing neurologic deficit. Um, just remember that beware of the patient that is sometimes, you know, referred to us too good for a candidate. The patient that is improving. Just remember that those patients sometimes do poorly without Ivy T P. A. Because there's still a clock there that's blocking the blood flow. However, their exam maybe fluctuating. Let's say with blood pressure. If you're augmenting their blood pressure or, uh, their auto mapping, as we would say, and keeping their blood pressures up. They may be doing okay because of collateral blood supply. And they're doing horribly when that collateral blood supply is not there. Eso it's care Carefully. Document time of last known to be well on den neuroimaging to make sure there's no hemorrhage before giving I v T p A. So here's some CT imaging of ischemic stroke when you have hyper acute stroke. Um, and you see someone within a couple hours from her from the patient stroke, you usually see no changes at all. Sub acute stroke meaning. After 68 hours, you will see this Hypo Density form within 68 hour, 6 to 8 hours. And then, after weeks, two months after a chronic stroke, you can see a chronic volume loss. You can see how the insula on the right side, which is left screen, um, is much bigger and more prominent, with some areas of volume loss and hypo density. Um, on this stroke that's been there for a long time. There are some early in FARC signs that is not always the most sensitive, but This is Ah, hyper dense M C. A sign where the middle cerebral artery and origin them One segment has brightness on C. T. Where there may be thrombosis. Um, you can see loss of gray white differentiation. Where in the middle image. If you look at that, you have lots of great white differentiation on the patient's right frontal area that screen left on. Then after days you could see that's much more evolved with a very clear, hypo dense area, the dark area on the right frontal area, the C T scan. There is an aspect score that we use. Basically, um, you get points knocked down from areas of the brain that have gray white differentiation loss. Here's a standard window C T scan. That's brain blood window. We can window that a little bit too. Uh, basically amplify, um, and exaggerate gray white differentiation. And you can see that the some loss of great white differentiation that you can see on the on the very far left side is amplified and you can see a lot more clearly. There's great white lost differentiation in the middle C T scan, and this correlates to an M. R I with diffusion weighted imaging that shows a large territory left Makkah Infarct on the Marie DW sequence on the right side. Here's some predictors of outcomes after I b t p A. Um, patients do better with obviously A Z talked about early time to treatment UH, age less than 70 Normal CT scan uh, less severe neurologic deficits and absence of diabetes, hypertension and heart disease patients with more severe, uh, symptoms. And I stroke skill greater than 20 major CTN FARC signs on Does core abilities we talked about have poorer outcomes and then advanced age over 80 years old high and I stroke scale. Uh, major early signs of CTE in FARC's baseline dementia, poorly controlled hypertension, thes air All, uh, increased risk of interest or cerebral hemorrhage after i v t p a on bond. And that could be a result of re profusion hemorrhage in the area of where the brain has been injured from the ischemic stroke. Relatively rare conditions such as, uh, or a lingual angio oedema. Uh, that can happen with I V T p. A. That's usually treated with diphenhydramine and maybe even steroids if needed. In rare cases, you need to administer epinephrine and get the anesthesiologist involved for possible intubation. If it's a severe Ana Fleck tick type reaction, so certain therapies that it's better to avoid if we can right after TP has given such Aziz Foley catheter, arterial lines and things like that Sometimes, uh, you have toe look at the risks and benefits when someone has poorly controlled blood pressure or has morbid obesity. And we're not getting a good blood pressure tracing from the cuff. And let's say we get a recapitalization, um, with mechanical thrown back to me in those situations that may be appropriate to get an A line in, even though the patients just had t p a, uh, to get more strict, a better blood pressure control. Just remember the T p. A. Um it catalyze is conversion of fiber inbound plasminogen to plasma in which cleaves fiber imagen from Platelet GP to be three a receptors and into fiber and split products. Um, uh. It's half life is about 3 to 6 minutes, but the terminal half life is 26 to 77 minutes, and the depletion of fiber fiber energy persists up to 24 hours and platelet inhibition persist for 12 hours. Fiber engine levels less than 1 50 are associated with interesting bill hemorrhage when hemorrhages suspected. And, um, you know some of those things that you wanna watch out for if someone who's given i v t p a for ischemic stroke develops headaches, nausea, vomiting or acute hypertension. Discontinue the I V T p a. Stabilize the patient. You know, again, your A b CS Um, get a stat C T head. And if there is hemorrhage, treat the patient with cryo precipitate and platelets. There's also on our website protocols for ivy T p a reversal. So, um, now we'll talk about endovascular therapy for acute ischemic stroke, mainly mechanical thrown back to me. Well, look at a video over here. So there are several ways to, uh, do mechanical thrown back. That means the two main being stent retriever and aspiration throwing back to me. Uh, here's a video that shows a clot, uh, within the left middle cerebral artery. Um, this is the internal crowded artery that by for kids into the anterior cerebral and middle cerebral arteries and then the middle cerebral artery by kids into a posterior an entire division or inferior Sapir division. Um, on these air the M two, Oftentimes the clot is right at the M c a bifurcation, and we will go in with a large catheter, um, from the common from our artery in the groin, all the way up into the internal crowded artery. And then we will, ah, put a micro catheter, um, through the clot, and then we will put the, uh, the wire Sorry, micro guide wire through the clot and then the micro catheter over it. We'll take the wire out and put in a, uh, a stent retriever, which is essentially a stent that is connected by a wire. And we will deploy this within the clot. And over time, um, the stent will expand with the idea of grabbing the clot. Usually, actually, the stent retriever goes on the side and not through the directly in the middle of the clot, But but grabbing the clot overtime is nonetheless, uh, similar phenomena. And at this time, you actually often see if you were to do an injection, which I sometimes do. Uh, during this time, you'll see partial re canonization. At this time, even though we haven't really suction the whole clot out. You can use a balloon guide catheter to reverse flow. And then during that time, where we have grabbed this clot with the standard retriever and we're bringing it back out and we will wreak, analyze the blood vessel that way. So, you know, when I did my fellowship about five years ago, uh, over here in neuron interventional was a really exciting time because, ah, lot of studies came out, uh, promoting that it was clearly, uh, beneficial in certain circumstances to do thrown back Toomey's. And it became, uh, really went from the wild, Wild West, where anyone could do whatever they wanted. Even though a lot of people, including, um uh, my mentors at this institution feeling strongly that thrown back to me is warranted to now being, uh, level one, uh, standard of care. So patients with large vessel occlusion who are eligible for I v t p a with large vessel occlusion, intracranial internal crowded artery, or M one segment of the middle cerebral artery. No pre stroke disability. So basically modified Rankin zero or one, then receiving I v tp less than 4.5 hours the night stroke Still greater than or equal to six and aspects we're talking about, Uh, that was a scoring system of, uh, essentially 0 10 of six and higher, where you haven't lost too much of the brain, uh, to, uh, already to ischemic stroke. Um uh, and that's again when you're looking, you're looking at the great white differentiation on time to growing within six hours of symptom onset. Then, uh, there were two additional studies that were for late, uh, recognize stroke or wake up stroke. And that was the dawn trial in the diffuse three trials. And we were, uh, one of the highest on rollers in the world for the dawn study. The doctor silo was the primary investigator. Uh, that was exciting. We were enrolling patients here and had, um, you know, really good outcomes on, but it was very exciting to see the results. And this, uh, expanded the window with advanced imaging for patients even beyond that. Six hours. So here's some visual similar visual aids that we were talking about with I v t p a. With endovascular uh, thrown back to me. Eso patients within the six hour window. Um um uh, for every 100 patients treated, uh, less than six hours. 34 benefited Onley. One was harmed. Um, and then for patients not eligible for T p a again, uh, even more people benefited. And then again with the 6 to 24 hour window, but again, with advanced imaging Um, in those patients, um, that's the major difference here. Um, that it's not that these patients have those more specific criteria that we'll talk about a little bit. 50 benefited, and only one was harmed. So, um, here's some endovascular trials. The five randomized trials that came out in 2015 and then again in 2017, don and diffused three trials that expanded our windows. Here are the two studies that, when you know, beyond six hours for wake up stroke and here's some inclusion and exclusion criteria for that Don and diffused three used somewhat similar Um uh, Don had a little bit more strict criteria when it cames thio Um uh, maximum volume of, uh, infarct. But it also had a more even more expanded window up to 24 hours instead of 16 hours. Um, and you can see over here. Here's the modified ranking scores at 90 days withdrawn by throwing back to me versus control, which was best medical management, and you can see the huge difference. Uh, with you know, again, we're looking for modified ranking of zero one or two, which means essentially functionally independent, with very minimal to no deficits at 90 days, and you can see the huge difference. Um, withdrawn Beck Toomey's, um, instead of medical over medical therapy um, diffuse three very similar results. So this changed our clinical practice guidelines, obviously. And we added the don trial imaging criteria and diffuse three imaging criteria that we now use for any patients beyond the six hour window that has a large vessel occlusion. Um, um, uh, that we consider for advanced imaging. Um, I think this is just kind of highlights those things that we're looking for. And here's some updated guidelines. Um uh, perform a non invasive vascular study as quickly as possible for patients who meet criteria. Um, but do not delay i v t p a. Proceed with c t a. Prior to obtaining, crafting and patients without a history of renal impairment, because that's just gonna delay the care. And, uh, it is not recommended to perform additional imaging beyond CTC ta or M r m r A for patients with stroke onset less than six hours, meaning that again that advanced imaging takes time. Um, and don't do it. Uh, if you have a patient that's within the original six hour window, Um, uh, which we know patients already benefits so from so And then when there is when you're in that extended window beyond six hours under 24 hours, then you do have to get the advanced imaging, and we'll show a few examples of this, um, either CT perfusion or, uh, m r I uh huh. Um, you know, just the patients presenting symptoms alone can be sometimes a big predictor of large vessel occlusion. Patients with and I choke scale greater than six have, uh, pretty good likelihood of having a a, uh, large vessel occlusion in the internal carotid artery. Or are m one segment N c a. A patient with an eye trucks he'll greater than 10 have even better. Bigger specificity for that. Mm. Um, when acute stroke is suspected on the last known well is less than 24 hours. Um, you wanna get a nice stroke scale? Uh, prioritize evaluation for I v t p A. So you can get that in a quickly as possible and go straight to C. T. Um, if there's no hemorrhage, um, administer the i V t p a ineligible patients if and I stroke scale is greater than six and less than 24 hours. Go to vessel imaging, usually with the C t angiogram, Um, with head and neck. If seti a shows a large vessel occlusion, uh, then, uh, transfer the patient Teoh University Hospital's Cleveland Medical Center Uh, we're working right now on expanding, uh, thrown back to me therapies out to a Hoosier medical center as well. But for right now, transfer of care to one of the throne back to me sites, university, hospitals Uh, CMC, uh, to consider, uh, you know, either thrown back to me straight to there and back to me or advanced imaging. If it's a beyond six hours, um, r i v a t p i v T p. A goal is within 45 minutes. Um, remember, good outcomes are more likely if there's good overall collaterals, and, um, but eso a patient may be doing okay or fluctuating, but generally collaterals decline over time. And those patients, uh, don't continue to do well. So, uh, um uh, a patient that is kind of fluctuating, but has a large vessel occlusion. You wanna air on the side of doing it thrown back to me if they're eligible? Um um, on because those collaterals we're probably gonna go away and they're gonna be on the worst end of their exam. Um, time is everything. For every 30 minute delay and timeto endovascular treatment, that translates to a 10% decline in the probability of a good, functional outcome. After you've done your throwing back to me, it's very important to figure out. Well, why did this patient have a nesky pick? Stroke to begin with? Um, ISAT intracranial atherosclerotic disease within the vessels. Um, is it extra cranial after Socratic plaque in the carotid IDs? Uh, that m belies door O. R uh, ruptured and included the vessel. Uh, is it aortic plaque? Uh uh. Atrial fib. Relation that causes rumba. Symbolic cardio. Anabolic stroke. Um, thrombosis in the left ventricle. Andi, this is another slide. This is a study in jama neurology in 2005 that looked at almost 2000 patients and about 13% of those patients with acute ischemic stroke ended up having a worsening of their stroke. And this looked at, well, you know who are like which of those people are were likely tohave worsening of their stroke. And one of the biggest risks is actually a patient with a large vessel occlusion. So, you know, vessel image ing is extremely important. Um, even beyond just the ability to do thrown back to me or are being eligible for a throwback to me, it also tells us you know which of those patients are at increased risk of stroke worsening in the acute period. Uh huh is off. All the vessels are open. And that's amore cardio, anabolic, crypto genic or a lacuna stroke. They're much less likely to get worse. Uh, in that acute period than a large vessel occlusion. I have a couple of cases that we can go through here. Um, first cases a 64 year old man with a history of smoking and atrial fib, relation on a picks, a ban. However, he was non compliant on the medication hey, presented to try Point e D via E. M s after his daughter heard him fall and found him unresponsive on the at 3. 30 in the morning at Tri Pointe is a nice stroke. Scale was 17. His blood pressure, uh, was relatively normal. Heart rate was elevated at 1. 26. And his, uh, cat skin was negative for any sort of bleed, but did have a hyper dense right M c a sign. So no tp a given was because of his patients, a picks, a band, and also kind of unknown time of onset, you know, this is controversial. You can you can argue. Well, his daughter found heard him fall. And maybe that is the onset. Um, but really, the last known normal for this patient was before the patient went to bed. So, technically, this is an unknown, uh, or last known well was the previous night. And this is a, you know, wake up stroke. Um, he was transferred to the university hospitals, Cleveland Medical Center. His n I stroke scale was against 17 here. Um, he was taken for advanced imaging with m r i m r. A rapid protocol and Rapids, a software that helps us determine. Um uh, determine, uh, volumes for ischemic brain and brain that is at risk and calculating a penumbra, which is the mismatch between the area that's at risk and the area that's already dead. Um, here's the D W. I sequence of them are I, um You can see that on their rights, right brain left side of the screen that there's some diffusion restriction or infarct already, and the deep structures in the basil ganglia. The patient does have this what we call in Iraq noid cyst. Most likely that's relatively large and the left side of the brain that's inconsequential. He's probably had that his whole life on M r A. Shows a cut off of the middle cerebral artery m one segment on the right side. And here's some, uh, um maps to show us what area of the brain is actually at risk. And you can see here that a relatively small area of the brain on the D W I sequence is actually dead, whereas the majority of the right side of the brain is actually at risk so very high, uh, penumbra and this rapid software calculated that to where? Um, the affected infarct brain. I was 11.9. Uh, and, uh, the area at risk are, uh is 123. So huge mismatch over there. So we took this patient to narrow angio kind of under the dawn criteria because this is a wake up stroke. Um, And here's the cut off. This is an injection into the right internal crowded artery, and you can see there where the internal crowded artery splits up into the anterior and middle division. And just as it splits up into the middle division, there is a cut off there at the most proximal segment of the middle cerebral artery. So this is the M one cut off way, uh, did a strength retriever throwing back to me here, um, and got a full recapitalization over here where you can see the middle cerebral artery is now re catalyzed and flowing. Um, so time is brain. This was ah, last known. Well, technically was the night before 23. 30. Uh, Andi, The daughter heard him at 3. 30 in the morning. Tri Pointe, we've got there at 4. 30. Um, hey was admitted to you H at 6. 40 in the morning, growing access at 8. 55. Oh, revascularization time was 9. 54. Um, we got a full recolonization. A tiki. Scoring is something we used for the amount of recount amount of blood vessels that freak analyzed, and three being full recapitalization and zero being complete, cut off without any flow beyond the area of occlusion. So we went from Tiki zero to Tiki three. Um, and, uh, post procedure immediately. Has a nice stroke. Skill improved from 17 to 9. Um, hey, had his work up and was found that this was cardio metabolic on, but he should be on his a pixel ban. And there was education given to him for compliance with the medication on, but he was discharged to keep rehab facility with an eye stroke scale of two compared to 17. So pretty fantastic outcome for this patient. Um, here's some follow up imaging you can see again the left side of the brain. There is that Iraq noid cyst and you know, very easy to be fooled by that and think, Oh, what's going on there? Is that a bleed or mass? And is that what's going on. But remember, this patient had left body symptoms, right? Brain? It's really completely unrelated to this arachnoid cyst that's been there his whole life. His real problem is the stroke on the left. Sorry. Right. Middle cerebral artery. Uh, occlusion you can see on the m r I that there's some, uh, infarct in the, uh, basil ganglia. Um, but outside of that, the majority of his right side of his brain is, uh is intact. And, um, the blood vessels are fully open with the right M c a territory. And there's no profusion deficit. Uh, follow a profusion imaging. One last case. Um uh 62 year old man with history of hypertension to slip anemia, aortic insufficiency. Who had a valve replacement in 2001, Presented with acute left sided weakness. His and I stroke scale was 15. Hey, had stopped his aspirin for a hernia repair he underwent earlier on in the day, mhm following discussion with the surgeon who performed the procedure. Uh, said that any sort of bleeding in the abdominal wall we could control on DWI decided thio proceed with I v t p A. After that discussion, andan the patient was transferred. Um, we got an m r I on, uh, profusion imaging. You can see here that the right internal crowded artery is really almost non existent. Kind of ends in almost a stump, and there's maybe trickles of flow at some point. And there's also an occlusion of the right middle cerebral artery. The internal carotid artery on the right side again, screen left, um, reconstitutes at the level of internal credit already terminus. And you can see a wisp of, ah flow in the anterior cerebral artery and then also the proximal m one segment of the middle cerebral artery. But really not much beyond that, you can see the area of actual infarct of already dead brain is actually very small on the diffusion weighted imaging on the top left hand side compared to the area that is at risk right next to it, which is really essentially the whole middle cerebral artery territory. So this patient we took too narrow angio. Uh, this is a right common carotid artery injection. You can see the corroded artery bifurcation with a what looks like a ruptured, ulcerated plaque causing critical flow limiting stenosis of the proximal right internal crowded artery. You can see the external crowded artery and its branches as well. Um, so this gets tricky of what you do over here. Um, because patients with neck occlusion or neck critical stenosis thes patients were, you know, excluded in the lumpectomy trials. And it's still controversial. Now, of you know what to do in this area, some people will say you should only angioplasties and, uh, angioplasty and not put a stent down here. Um, because of the, uh, chances from instant thrombosis, if you want to give high dose anti platelet therapy and giving high dose anti platelet therapy increases risk of hemorrhage in the setting of I v t p A. There's a lot of back and forth, um, way decided, um, in this case because of how narrow this was, um that we would do a stent and kind of do a half dose Plavix type of situation. So, um, you can see the severe limitation of blood flow and the right internal priority distribution and middle cerebral artery territory with the injection we stent in the area and you can see how we've opened up the right internal crowded artery. The flow immediately got dramatically better. But there is, um um some, uh, important middle cerebral artery territory. Branches that are missing eso Then we went through the standard crowded ended aspiration throwing back to me, and was able to open up a majority of the right middle cerebral artery branches and increased profusion. Um, we got a tiki to be re canonization. I would say in this case, his and I stroke scale improved dramatically. Eso this was really a combination of two things. One was the critical stenosis causing flow limitation and thrombosis in the middle cerebral artery, causing no flow to certain areas of the brain. So, um, on the patient was discharged on day two. Um, we decided again on that case to do a, uh, half dose Plavix load that night after the stent placement of 300 mg and then 300 mg the following day. Again, this is ah, a kind of a hot, controversial topic. You'll have people on both sides of the fence where, um, you know, 1 may say, do not in any circumstance put a stent in and the cute throwing back to me and other times where it may be appropriate. Andi, I think with endovascular therapy and the setting of acute stroke, you know, there are a lot of cases like that. You know what? Which m two or even m three occlusion? More distal inclusions. Do you go after, um uh, and when do you go treat and acute neck conclusion versus other times where you don't And, uh, there's a lot where There. It's not black and white. Um, on And, um but I think you know, this job's very gratifying in the sense that's one of the few things we do as neurosurgeons on your interventionist, where you see a pretty dramatic response and you can really affect the quality of life of someone. And they could go from really being nursing home bound with the track and peg to walking out of the hospital potentially, Uh, And, um, here's a picture that I took when I beat the helicopter here for acute throwing back to me. Thank you very much.