Young Neurosurgeons Discussions with the Experts; EC-IC Bypass surgery 1980-2025

SNI Digital Innovations and Learning, a video journal which is interactive with discussion. Now, offering this program and all of its others on podcasts on Apple, Amazon, and Spotify,

an association with SNI, Surgical Neurology International, an internet journal with NCF as its editor-in-chief, are pleased to present a new SNI Digital series on young neurosurgeons discussions

with experts.

This first in the series is with Rob Leonard, who is from the University of Utah, Eric Nussbaum and James Osman. The topic is our experience with UCIC bypass surgery covering 55 years in several

vascular

Dr. Leonard is Assistant Professor and Associate Program Director for Neurologic Surgery and the Residency Program at the University of Utah and Director of the Skull Base and Vascular Anatomy

Laboratory.

His references are his background. Fellowships and training are listed here, starting with Medical School at Ohio State, residency at San Diego, at the University of California, and fellowships

at, in San Diego, at the University of California, University of Arkansas and at Utah and at

USC, in Reserval Vascular Surgery,

Skull Base Surgery, Neuroendovascular Surgery. Dr. Nussbaum is well known in, by 2SNI Digital He's the chair of the National Brain Aneurysm and Tumor Center, the Director of Complex Cranial

Neurosurgery. Midwest Mine and Brain Center in Minneapolis and St. Paul, Minnesota, and the Associate Editor-in-Chief of SNI, and SNI Digital, and he has 35 years of experience in several

vascular surgery and neurosurgery.

These are some of Dr.

Nusbaum's publications, and you can see there from amazamarthemecom. He has

multiple scientific publications and PubMed and on

SNI. Dr. Osmond's a creator and CEO of SNI and SNI Digital, editor-in-chief of SNI Digital, former professor of neurosurgery at the University of Minnesota, Michigan, Illinois, and UCLA,

former chairman. If you'd like to participate in this SNI Digital Young Neurosurgeons series, discussions with experts, please send us your CV in a brief summary of your interests and work. We are

interested in creative and innovative ideas from young neurosurgeons worldwide as models for others. Send your CV and summary to Dr. Osmond or Dr. Nussbaum at the email's listed below. First off,

just thank you. I really appreciate the opportunity to present. It's been nice to see some of those other videos that have come across and it's an exciting series. So I really, again, just thank

you And so my background is I did my neurosurgical training at University of California, San Diego, did endovascular as part of my in-folded training and then it did extra open vascular and

skull-based training at a few different places. One with JD Day at Arkansas and then a full year here at the University of Utah with Dr. Caldwell and then additional time with Dr. Russ and at USC

So I've tried to pick up as much as I could from. my mentors and have a skull-based and vascular practice now here at the University of Utah. And I think you had a background, you got a PhD in

something, didn't you? I can. I didn't get a PhD. I

did about three years of basic science research before residency, but I didn't get a PhD and I was doing stem cell work

and a little bit of translational work regarding stem cells and stroke and then stem cells for a few different clinical applications. Okay. And

so you guys are, oh, you have how many people doing vascular work at Utah? There are five total. So there's four dual-trained enovascular and open vascular nurse surgeons, me, Carl Budahowski,

Ramesh Grande, and Craig Gilbert and then Dr. Caldwell does open basket. Okay.

What's your long-term goals?

So,

really to continue building practice in complex cranial surgeries. So, I have a passion for open vascular, in particular for cerebral revascularization and bypass. And I think I got that through a

few of my mentors, Dr. Caldwell and Dr. Russin in particular, to try to innovate in that field and then also continue with open vascular surgery as an adjunct to endovascular and kind of really

have a open decision process in treating these patients and coming up with some hybrid solutions or really whatever is the best option based on individual patients and clinical indications.

As a percentage of your work, how much do you do? Just trade bypass versus intracranial grafting.

To clarify, do you mean with an interposition graft versus just a single donor without an interposition? Right. Most of it is, I would say the simpler non-interposition graft at this point, the

indications for higher flow with interposition are just fewer and far between. So the majority of it at this point is

direct bypass with lower flow indications. Okay. And how do you measure the lower flow?

So I'll get into that a little bit, but

with STA versus

an interpition graft from the more proximal, ECA, but we've done some work with the Sharbell flow probe looking at how to manipulate the STA branches, try to optimize flow in these flow

augmentation settings, and also just get actual quantification of the flow levels.

How do you select the people before surgery?

So for Moemoya, it's probably more defined, basically people with symptomatic Moemoya disease. And then for the extent of occlusive disease, it's patients who have failed medical management with

flow deficits on imaging is,

and who don't have a good endovascular option. And I'd say the last part of that's the one that's changing the most, with the basis trial and evidence for angioplasty, people are getting a little

more aggressive on that Bypass is maybe becoming a less frequent for those patients who who historically or at least in the recent future Or in the recent past would have would have been candidates

for for bypass

Are you any questions before I think the real meat of what we want to see from Rob here is some of the cases he's doing right? Eric Yeah, I think so. I'm so how much relask worker you guys doing

like how many times a month are you doing a bypass low flow versus high flow? Just curios. Yeah. Um, so the the main people here who do bypass our me, um, dr. Caldwell and dr. Buddha house

case is actually three of us Uh, which is is a high number for any institution. Um, especially given the relatively low indications, but I would say we're a pretty high volume center overall. I

mean for example this past week we did three I did two and dr Dr. Budhaski did one.

All low-flow STA2 STMCA, and one was actually a case I'll present today which was an STA to ACA for kind of unique indication.

But I'd say on an annual basis, probably on the order of 20 to 30, probably closer to 30, the majority of being lower-flow. So it may be 25 to 5-ish ratio

Okay. Well, I think there's no point

in us at this point going through the randomized controlled trials. I think you reviewed that in your talk pretty well, but

I think there's still some difference of opinion And the one study you cited was in JAMA of 2025,

long-term follow-up out of China and so forth. And I think, from my point of view, And you know, we won't talk a lot about this because it's devolved into an issue of emotional rather than logical

thinking. And

there's a major deficits, and I think this latest study shows that, and that is the major mortality turns out to be, and you quoted it here. This is the graph, right? Can you see it? Yep, I

can see that. And this is the study, and the problem here is right here. This is a problem. Yeah. And after that, surgery stays the same. And unfortunately, I don't know, I don't know, I

don't know if we talked about this before, but to me, having a mortality or having death early on in an annual SDA bypass,

I think that's really rare and I don't understand the 30 day mortality or something's wrong. And that essentially biases all the statistics and this study shows it very well. If you had a lower 30

day mortality, the difference would be very significant. So anyway, we won't get into that. There's some major defects in the studies. If I didn't see you quote the articles in the New England

Journal of Medicine, early studies, and their comments on it by Thor Sunt. Do you remember who Thor Sunt was? I do, I never interacted with him personally, but I'd certainly have heard of him.

Yeah, Thor was an authority in this stuff and revealed the corruption that study, they could, went back two and three times, they could never get the same data twice and it wound up being a

political issue and so forth and so on And after that, there was a.

a lot of, there was a lot of corruption in that study. Nobody wants to report that because it was the first surgical study to be randomized and they wanted to, they put a lot of effort into that.

The government put a lot of effort into it and

basically, it was at the time when coronary bypass surgery was hit its fruition and it was really growing and they didn't want another category coming in with bypass surgery. They didn't want to pay

for it None of that ever made the literature, but that's contaminates all the earlier studies. So I think the thing to do is to get into, is to get into the studies that you're doing, what you

guys are doing and show us that and our audience is going to learn more from seeing what you're doing and have us an open discussion about. So you want to do that? Yeah, I'm going to say anything,

Eric, I

No, I mean, I'm curious. So it's interesting, more and more, it used to be a relatively small percentage of the revass that I used to do, and it's become an increasing percentage, maybe along

the lines of what you had alluded to. It's an interesting population. I certainly, my experience, I agree with Dr. Alesman, has not mirrored that type of high mortality, but they can be

difficult patients to manage in terms of perioperative, ischemic stuff going on I'm just curious what your experience has been. Have you seen an 8 or 10 mortality, and what are you seeing in terms

of

the morbidity, and by morbidity, I'm really mostly interested in perioperative stroke? Yeah, I must admit, I don't think we here, and me personally have seen certainly the mortalities from this,

I have this discussion We had a patient. This past week, who had

a cabbage in May, really high risk from just a cardiovascular standpoint and had flow dependency from the left-sided ICA occlusion and his collateral flow was tenuous. So,

he was a tough patient, I think probably about the highest risk peri surgical that you could get, or perioperative And

he was, we weren't able to do our normal things that we do for these surgeries with birth suppression. I can only do EG without SSEPs or MEPs

and we couldn't really control the blood pressures that well. But ultimately, he went through surgery fine without any strokes and without any cardiac events. So, that's somebody that sticks out

as about as high risk as you can get and we were able to get him through from a an aesthetic standpoint with dedicated.

neuroanesthesiologists, and I think that's probably the biggest difference, you know, I have a slide on it, but you know, there weren't

intraoperative

pathways that were established during those trials,

to my understanding, there weren't dedicated neuroanesthesiologists, it was really unclear about the monitoring status, and I think

if you're able to do those things, the risk is relatively low. I mean, you're using birth suppression for a bypass, is that because you're worried about the cross clamp time, or what are you

thinking there? Can you stop sharing so we can see each other full screen for a minute, Rob? Yeah. Okay, and then we'll come to your cases, but this is good We're into the heart of this,

good You know, that's something that. was done when I did my fellowship here with Dr. Caldwell and I have continued it. The idea is exactly that. I mean, it's an M4 vessel. It's small. I think

the collateral flow to that is gonna be picked up and the risk of stroke even without burst depression is quite low, but just basically adds another level of protection is a thought while you're

augmenting their blood pressure during the case. Okay, no, I was just curious. I haven't ever used that before

What kind of operative time? What's the, how long are you cross clamping the M4? And what's your total operative time? I'm just curious because I've seen a huge variation from institution to

institution. Yeah,

you know, I think on average the cross clamp time is 30 to 40 minutes and that's gotten lower as I've done more and more, which I think is

within the realm of what's published

There certainly are people who do it faster and overall operative time is on the order of on the low side, maybe three and a half to four and a half hours somewhere in there. Okay. We try to do it

pretty quickly.

Just for again, a lot of these patients have comorbidities, cardiac issues. We tend to think and I tell the patients that the biggest risk in the surgery is really going under anesthesia, their

indications for surgery are they have tenuous cerebral blood flow. So, you know, what we do doesn't necessarily affect that very much. It's just if they drop their pressures in the OR, their risk

of stroke is not insignificant. Completely agree. And for Moya Moya, are you preferentially or always doing a direct bypass or using, you know, in the younger kids, for example, I don't know if

you're operating on that population, Are you doing any of the.

peal synongiosis or EDAS or any of the other procedures. Certainly for the adults, we'll do combined and that's a direct width. We do an edam, so we invert the dura, tuck

that under the bone edges and then actually do a hinged bone flap where we suture the temporalis muscle together first and then put the bone flap on top of that to allow the muscle to gently settle on

the surface of the brain So you get revascularization indirectly over time from the dura and the muscle. And there's some data, not level one, but retrospective cohort data to say that direct or

combined, at least in adult, ischemic or

atherosclerotic disease. I think also for Moa Amoya is better than indirect as far as long-term stroke prevention. Kids is a bit of a different story.

and they have a good STA size-wise. I don't think you lose much to give them both. Obviously, they have a higher propensity to grow in blood vessels and you may not need that. So it's a bit of a

mix. If they're older, we certainly done a combined on that more if they're younger. We'll do this to indirect. I agree. Why don't we go to some of your cases 'cause it'll give us a chance to

bring out all these things for the audience and so forth. Okay. Okay.

I'll share again here.

So, this is just to show overview of kind of how the field has progressed over time with all these trials and don't need to necessarily get into that.

You can go by that. Yeah.

These are the two main ones, ECIC, CAS,

and CMOS I think this may be worth highlighting just this slide in particular or this graph. So

we alluded to it earlier, or you did just or showed it, that the long-term CMOS data basically affects this curve here, which is in these patients with decreased reserve, their long-term stroke

risk over four or five years is quite significant, almost 40. So

if you look only at two years, you're less likely to get the benefit of a bypass, but if you look over, in that case, the CMOS fall update of seven plus years, you're just more likely to see the

benefit of it. So this, I think, is probably the biggest criticism of all these trials. They're relatively short-term follow. I think

it's

a good point. You go through that? Yeah.

This is a point I sometimes make is that, you know, just because initial randomized control trials fail, you know, we know from the stroke data that that doesn't necessarily mean that they were

done correctly and there's not a signal there. Also for

ICH. I agree with that, too. The original data has to be discarded. It was totally corrupted study. It's of no value. Subsequent studies really didn't approve it very much. And

that graph is very significant. It shows you what we just talked about. If you eliminate the earlier mortality, what happens?

Yeah, exactly. You alluded to that, we've talked about it. So, but I think unfortunately, I don't know, I haven't looked at it recently, Eric, I don't know if you have but the American Heart

Association Stroke Council still has really outdated analysis of the bypass study. It's incorrect and they never evaluated bypass for post-year circulation in any form. And it's still ruled out And

that's just a tragedy. It just,

what it did is destroyed neurosurgical

input into the vascular field. Some of that was intended. Okay, go ahead. Yeah, yeah, and I have a few slides on post-year circulation, but I think you mentioned is a good talking point as well.

Yeah, and okay, go ahead and go in behind. Let's go to the cases Yeah, and this is just some videos. You know the thing, you just had them that slide is payancy rate.

I don't know, what was your payancy rate and how do you measure this, Eric, and what you did? For me? Yeah. So early on, probably for my first 150 bypasses, I did an antigram, either

intra-oper post-op on every patient. I thought it was very, very important to know. I mean, we'd get into it. It was a big problem that I had with the, you know, with the JAMA study from 10,

15 years ago, because they only used ultrasound to look at patent and see, and I'm not sure I trusted it, and I had an issue with it, and I talked about it with them in some of their planning

sessions. But, I mean, I think, you know, if you can't maintain patent and see after the surgery, then there's no reason to expect that the surgery would be effective or beneficial to the

patient, and so I think it's critically important. More recently, I do the ICG in the operating room see that the bypass is open. and I've accepted that. And then post-operatively, we'll do an

angiogram of patient has an episode of any kind, you know, any type of TIA or anything like that. I wanna know what's going on with the bypass. When we did this very early on and did lots of

angiography, because it was really the only way you could tell what was going on in the circulation. And we did four vessel surgery by angiograms. You do that, Robert? We do, ICG, video

angiography, which I think is good intraoperatively. I mean, I think you do get definitive answer as far as flow with that in addition to the Doppler. So we end up doing six month angiography on

all the patients as opposed to immediate and then I get an immediate post-op CTA Um, so. you know, I think with the combination of ICG and CTA, I can say definitively that these bypasses are open

immediately, and then we look at six months with the NGO. But agree, if there's any question or issue or they have problems post-op, we'll do the NGO right then. I think one of the studies you

showed at a 90 patent say, I think that would be extremely rare in our experience. And we did angiograms on everybody because there was no other technique at the time they didn't have intraoperative

flow measurements or anything. And we did it liberally. We did it after surgery. We did it and we then brought them back and did it repeatedly. So you've got long-term data and one of the things

you were able to show with that is you were able to show that the bypass grew. It grew from the day you did the bypass and it depended upon the collateral, the collateral circulation to the brain,

which is why we did four vessel angiograms. And I don't I'm not confident actually in CT angigrams. But four vessel angigrams, you could really evaluate what the flow was to the hemisphere. And

you could see how it would adjust if they had a middle cerebral occlusion and how the flow would be redistributed. And you just don't get that idea. You can get it with a flow meter at that time,

at that moment at surgery. But, and Fadi had done some postoperative flow measurements which really didn't take off very much but it was a very, very innovative technique. But in the end, in

essence, if you don't understand what the flow is by angiographic, angiographically, by four vessels, you miss a tremendous amount and you also miss growth. And if you, for example, in Moya

Moya and others, initially, we didn't put the bone flap back. It was, you know, a little small hole. And if you didn't put the bone flap back, you could see in those people who had a a vascular

deficit, they would revascularize through the muscle onto the brain surface. And it was all related to the amount of collateral flow.

And so those people, in fact, we even did a separate study where we had people who had very compromised intracranial collateral,

and they developed very robust bypasses because obviously there was a great demand And another time what we did is, when they had carotid aneurysms,

I think we talked about it. You did that once, I thought, is you did a bypass, and you didn't want to close off the carotid immediately. So you took a silverstone clamp and put it in the neck,

and you included it down to about any percent. So you cut the flow, and you did it and it repeated angiograms. And after you saw that the

bypass was taken, than it usually took about. a week to become increased and so forth and so on, then you could put the clamp down. After a while, we didn't do that, but it just shows how

important the collateral circulation is. So, okay, why don't you go ahead with the cases when you've talked about some things as we go. Go to it. Yeah, yeah, and just to follow up, I don't

know if you can still see the screen here, but to follow that point, that study with Dr. Sherbel does show that there's about a 50 decline in these direct flow rates at six months. And it's a

little bit unclear. And if you do the same bypass in every patient, why some patients have an ingrowth of the direct bypass and others have a decline in that direct bypass. And we see that it's

an inverse relationship with the indirects based on their

preoperative flow deficit. And then actually another thing that we looked at is how you manage the two STA branches. So this is a retrospective study from my fellowship here, but the two factors

that influenced direct flow at six months was, again, their preoperative deficit on perfusion and then whether the non-donor SDA branch was taken. So in patients who had the non-donor SDA branch

taken, they were more likely to have higher flow rates within their direct graph versus their indirect And then this first was true if it wasn't taken. Okay, let's come on to the cases. All right,

so

this recurrent strokes despite mask medical management, they had a right ICA occlusion. They actually in this patient had progressive left ICA stenosis which kind of complicated things, more than

the standard patient can see their strokes, see their flow deficit all on the right side here on perfusion This is their angio. basically showing that ICA ends

right as it's going into crannily and then there is good cross filling across the ACOM, but obviously it's not enough with its perfusion and recurrent strokes. And then this is the left side where

there is some progressive stenosis in the superclinoid ICA region. Yeah, good. So this guy is compromised. Yeah And you know, I guess there's some

question how you could manage this patient. If you felt that the left ICA flow was the limiting factor, you could theoretically just stent that side and try to augment flow to the contralateral side.

But we weren't sure whether that was flow limit enough. So we ended up doing a bypass low flow to the right side And then secondarily stented the left ICA. This patient had a very nice ingrowth of

their direct bypass here. This is at six months. You can see a fair portion of the MCA filling through the direct bypass. And then there's less cross filling needed since a lot of that is filling

through the

graft. And then this just shows the secondary standing of that left ICA. So, you know, these are kind of the normalization of perfusion deficits that we see pretty standardly

with this bypass. What did

the vertebral basilar circulation look like? I thought I had that, but I think in this case, there was some pure collateralization from the right PCA. I guess I didn't show that, but that's

fairly common, you know, with these patients as well, obviously.

And so, what happened to the right carotid? Did it, did it, did it, did it, did it.

This is a common injection here. So there's, I think that I just didn't hold it out long enough or I didn't get an image that held it out long enough but it filled the same, it just stopped as soon

as it went into cranial, right at the ophthalmic level.

I think it's a good case. I guess my only common is I like how you say like the ingrowth at six months. I mean, my suspicion is it would have looked pretty much the same a day after surgery. You

think that there was a big change because this is, I think, kind of what one might have expected. Yeah, that's a good point.

We tend to - obviously, these are dynamic. They don't look the same immediately after as six months. So

you're right. It may very well have looked exactly like this preoperatively. And that's an argument to do an angio immediately and even maybe at six months both to see how it evolves. Um, I think

just from an academic perspective, I mean, again, probably from Jim and I haven't done a lot of early post-operative angiography, it's fairly unpredictable, but it's not that common that, you

know, it's barely filling immediately after surgery and then you get a lot more filling. I think with the indirect, obviously you're going to see the changes, but this would be very typical for an

immediate post, you know, in my experience for an immediate post-operative arteriogram to look like this. Yeah. What's interesting, there's a study recently at NYU that looked at the suturing

technique and long-term flow rates and they actually showed that

a running anastomosis promoted better

long-term growth or long-term filling of the bypass as opposed to interrupted. I know people have traditionally felt the opposite, that the interrupted allows it to expand further I'm curious, what

do you normally do?

Personally, for STAMCA, I pretty much always do interrupted. Once in a while, if it's a really big vessel and it's kind of laying out perfectly, I'll do a running on one side maybe, but I've

always been interrupted because I think it's more, allows me to be a little more precise and for exactly the reason you just suggested, I suspect that that's maybe a self-fulfilling prophecy in the

sense that if somebody's more comfortable doing running and they like it, maybe they do a better job with it, you know? And so then their long term, it looks better, but it doesn't make much,

why would, I mean, it doesn't make any sense intuitively that you do a running and that you're gonna get better flows later on, I would think the opportunity for expansion would be better with the

interruptives, but maybe there's something counterintuitive about it. I like the interruptives for these, I like the running for, you know, the high flow for aneurysm, you know, for vane graphs

or things like that Interesting. Why do you like the running for the bigger vessels? Oh, I just feel like you have to put a lot of interrupted sutures in, and so she goes quicker.

Early on, we looked into that, and it came from the vascular surgeons. Actu is a guy I didn't refer to by the name of Solaji, who was a very famous peripheral vascular surgeon, a surgeon, and

they did a study of interrupted versus running suture. And that's where this conclusion came, that if you did interrupted, you would have growth of the bypass. That's where the study - that's

where it came from. And so I basically did what Eric did is we did him interrupted. And until if you go down and do a deep bypass,

you don't have that luxury, or you can do that. But it's a lot more maneuvers. And what you can do is if you take - You've got to have a long needle holder to do that. you go down there and then

you can make a running suture. The problem with that is you don't know what's going on in the other wall. And if you catch the other wall, you've just occluded your bypass. And so we always use

stents. I know a lot of people don't do that. We always use stents and we take them out. The problem with stents is you do, it does damage some of the endothelium, but it does prevent that from

happening And I know there's differences of opinions about it, but that's, so ours is pretty much what Eric was doing. And if it was a bigger vessel, yeah, I can understand that, but that's

where that data came from. And I'm still looking at this angiogram here. Now this was done how soon after surgery in this patient? Six months. Six months. And initially when you did it, the

carotid was not filling beyond the terminus must have been very stenotic, right?

Yes, yeah, it basically occluded there. Yeah, it was basically occluded, yeah. Okay, but you see, there's a little retrograde perfusion into that. So if it's highly stenotic or basically

occluded, and if you did that anceogram, you got pretty good filling on the, and this is qualitative, on opposite right side, right? Now you go to the post-op film that you did, and

you're

basically filling all the way back down, probably to where the carotid was, right? And we may not see it because the flow may be so slow that it doesn't show up in the angiogram, and the diasin

going by as robustly, but, and it's not going to the other side,

and you're still filling cross from the, to the right to the left. Any thoughts about that, Eric?

No, I mean, just what I said, I think it's very unpredictable You know, we have some. it would be interesting we could we could sit down again together the three of us could sit down and look at

I mean I could share probably and I'm sure Jim you could like 25 post-op day one angiograms and some of them fill out a wedge of the middle cerebral territory because the collateral is taking care of

the rest of it some of them fill out the whole hemisphere

some of them when there was a problem in the other hemisphere actually crossed the acom and fell out part of the other hemisphere or a lot of the other hemisphere and i think there is a dynamic nature

to it why that happens i don't know but sometimes it might look different at six months i don't know that it matters as long as the patient's doing well and they stop having problems um but i do think

there's some unpredictability to it um for whatever reason i think the the only time you really get into trouble or with some of the occlusive disease or moi or more you know you can you can sometimes

get a vessel that's disconnected from the other vessels. And so. You can, unfortunately, once in a while, bypass into a vessel that really isn't connected back to the middle cerebral tree, for

example. And I have some examples of that, most notably in some aneurysms, where I wanted to do a bypass, and then an occlusion where post-update one or two, we did an angiogram, and we saw that,

unfortunately, the bypass wasn't connected back up, and I had to go back and do a second bypass to a better vessel. So that happens occasionally More with the moia moia, I think, more with the

very bad occlusive disease, but

yeah, this is a great case. I think this would be a classic example of a patient who one might expect would benefit from the revascularization on the right side. And when you mentioned the stent on

the left side, I would have done this first, even if you were planning upfront to do the stent, If you have a problem with that left-sided vessel related to the stent, then she's really in trouble.

Once you have the bypass in place, you have a lot more comfort level doing that. And our experience with angioplasty in stanting the enter circulation has not been that great. I mean, not in terms

of disasters, but in terms of recurrence stenoses, we've had a lot of trouble at our center with that. And we have very strong endovascular and they do a great job But it hasn't been long-term so

happy. I don't know, like, do you know I have long-term follow-up of the left carotid stent in this case? I'm just curious. No, not in this case. This one's probably within the last year. So,

you know, we'd have to look. I would say, you know, we've done more and more recently as a group, you know, especially my partners of intracranial stenting with these blue-mounted cardiac stents.

And that's what you're using. Yeah, that's what Sharp Bell's using. Body's using those also, yeah. And the outcomes I've been impressed by for the most part. So I think it'll be, it's certainly

a moving target. Keep an eye on it. I just saw a patient from Chicago who had one of those done and they had a pretty severe stenosis at 18 months and ended up needing a bypass. So that's the thing.

I mean, I think you're exactly right that, short term, even intermediate term is okay, but if the patient's 50 and then you get a stent, even when they're 65, you know, what's going on? I kind

of a suggestion, Rob, as you, we talked about it and I sent you the paper on a vertebral basilar disease. As you get into this, obviously you have to focus on the vertebral basilar circulation.

And it's very worthwhile since you're doing the anchogram anyway.

is to get, to do the, you have to do both vertebrales. You cannot just inject one. You have to do both. Because sometimes the other one as goes down the other way or it's, the flow is different.

You inject both vertebrales and you look and see what's happened to the rest of the circulation. My guess is what's happening in this guy is he's feeding this entire right hemisphere off a collateral

from his post to your circulation And you don't know that right now and you can't tell that. But you see the flow across the anterior cerebral and the picture on the right is less than it was pre-op.

So you've displaced it with some of the circulation on the right side, right? Yeah. But that doesn't fill out the whole hemisphere. So my guess is this man over time because he had basically two

very threatening stenosis. He had one in the internal carotid on the right and he had one in the, a stenosis on the left that you can still see there. And so he's got two of the four vessels

compromised. And my guess is he's gonna have robust circulation from behind and it's really worthwhile to know that because it changes your perspective on the whole thing. So, and you're right

there, you can take it, you can take a shot, you can always show it. And as you show the films, I usually show the whole thing. So, just as a pointer to you, think it would add a lot to what

you're saying, okay? Yeah, no, I appreciate that. We certainly did, I just, for whatever reason, didn't include it in the story. No, you look at it, you say, no, it looks okay, and so

for it, but you'd be surprised. Sometimes, a poster you're communicating is absent, and you don't know what it's gonna happen half the, 50 of the time, or one is small, the other is larger,

stenotic, I mean, there are all kinds of things you'd see. And people got rid of that when they went to CT, because CT shows you everything at once. and it doesn't show the posterior circulation

as well, and it doesn't show you the smaller vessel circulation. So I really don't like CT angiograms, although most people have gone to them, because it doesn't tell you the detailed vascular

anatomy. And you're gonna learn that with this, with seven Tesla angiograms, it's gonna make everything totally different, okay? Yeah, no question. I think it just tells you whether it's patent

or not Yeah, that's a good case. Okay, so what's the net? We got another case. Good case, another good discussion. Oh, there you go. This, so this one's a little bit different. This is

actually a very recent patient from this week. So I add her in. 72-year-old has some interesting steno-clusive disease of the bilateral proximal ACAs. So she has some cross-filling, or not

cross-filling, she has some PO-cloud relation largely from the bilateral MCAs. You got to show a vertebral injection or touch your cuspids could it be unhappy with you? She's filling the Colossal

vessels from the

back from the back, right? That's right. Yeah, they're they're fairly hypoplastic And I don't have it

But To

your point there is some filling from the from the PCAP O cloud was not a ton And she's had refractory strokes largely in the left ACA territory

But she does have

Flow deficits in both from a perfusion perspective. Yeah, it tells you that I think Eric's right is coming up the post-year circulation But it isn't enough. Yeah, so she constantly gets a

schematic and in the anterior cerebral distribution So I think you're absolutely right. So this one was was interesting Um, I can't say I've done a lot of direct

ACA bypasses, you know, the things that I looked for is whether there was anything big a three down in the hemisphere and her mascara Fisher that a jump graph could plug into, but she didn't really

have good filling of her a threes from anything and you couldn't see them very well even on

CTA. For whatever reason, they just had withered away. So I don't think there was really an option for a higher flow graft. And then I guess I considered just doing all indirect, which may have

been enough. But this was her lateral injection of the left ECA in that bottom corner. So she has a fairly

small parietal branch of the STA that I didn't think was going to help me much. I thought maybe this frontal branch, if I could get enough length and trace it out, you know, up here could give me

enough to do a direct ACA, cortical, in addition to some dural flip or pericranial graft on top of the brain. But I'd be curious, you know, if you had any other thoughts?

Let me jump in first. We, I think we reported it in Spassler reporting, and after that it was called a, we call it a bonnet bypass, which is what you were trying to do. You get a long length of

the STA out It's still a millimeter all the way out there. And then you can go across the, you can go in the hemisphere of inter, inter hemisphere, or you can, you can, you can bring it in from

one side and vascularize the other side, opposite side. And so that's, that's one way to do it. And, but, but she is really ischemic in the anterior part of her anterior cerebral. That's where

she's deficit What's your thoughts, Eric?

I've done about five of these with an indirect and gotten really robust collateralization and

very, very happy with the result. I've done only two or three of these direct. I've never been able to get the STA to stretch enough. I actually used the longer Ipslot or STA and then borrowed the

opposite STA and did it as an end-to-end a couple of times It works, but

the truth is that these days I would try and indirect first and I've been very happy with the results. I can show you some great pictures. In fact, I've been meaning to report that, but I haven't

and I need to hold some of those. What do you mean by an indirect bypass? Oh, yeah, I just mean, as opposed to doing a direct and astomosis along the lines of the internet, you know, an E-dass

or something like that or a muscle procedure, actually just do bilateral parasagittal strip craniectomies and leave the bone off and leave the dura open and the scalp and the dura will grow

neo-vascularization to the brain. And we've had really dramatic, dramatically favorable results with that. How old, well, 72 is a little bit older. I mean, I've been, had good experience more

than the 40 and 50 year olds with this, but I mean, obviously you're going to do a direct. So that's great. I mean, I just find it's, it's harder. And by the time you get it out far, it's a

small vessel. And, you know, sometimes I worry about how much, you know, it'll help, but let's see what you guys, what you guys did in Utah. What'd you guys do, bro? Well, it had all those

thoughts. And then the other, the other issue is with these frontal branches of the STA, probably about 50 of the time, they end up with a,

frontalis palsy just because they're, you know, the nerves are right in there, which I tell patients and it's not the, not necessarily the biggest deal to some people, but it certainly is a

problem, but it does typically get better in what I've seen. So my strategy was to take this frontal STA and trace it all the way out to about here and try to plug it in and not fully

interhemispheric, 'cause I didn't know whether I'd have enough length and have a big enough vessel to do that. But try to find a cortical vessel, somewhere around the vertex to plug into and then

combine that with indirect. So this is what we were able to do.

This is the frontal branch that was traced all the way out. This is a small window in the bone toward the vertex. This was

the distal ACA vessel that we were really with the new to the standard.

end-to-side anastomosis, flowed well on ICG

and Doppler. And then this is the CTA, just showing that graph going in, targeting that frontal region,

plugs in right about here. So not fully toward that inner hemispheric space, but certainly where I think those ACA vessels are. And then we did a paracranial graft that we laid on top of this that

was vascularized and then did a dural flip. So we tucked those dural leaflets on the surface of the brain in this area and then did bur holes on the posterior left side and then bilateral bur holes

on the right side with dural inversion. So again, this was a patient from this past week. She did fine from the surgery, didn't have any issues and long-term it will have to see, but I think

that'll hopefully give her enough, especially with the indirect growth. You didn't do an angiogram yet, right? No, not yet, okay.

Oh, I'm sorry. No, go ahead. Yeah, I was gonna say, look, I think it's a great case and I congratulate you on it. I probably would have done an angiogram intraoperatively just, I think you,

I would have been happier if your enastomosis was a little bit higher up on the convexity. You know, you're gonna get at the MCAACA watershed and hopefully irrigate the ACA, but you know, a few

times what I mentioned when I've done it, I've done an intraoperative angiogram just to kind of feel very happy that I'm bypassing to an ACA, a true ACA branch. I think it's a great case. Don't

get me wrong, I'm not taking away from it at all, but I think

you're getting beaten up by the older guys here who like Angioc, who love Angiography. No, that's fair. I like it as a, I mean, I just feel like it's, it helps. Of course, if you get up too

high, then you got to deal with bridging veins potentially and causing other problems. But

I think in and of itself, it's a great case. But I'm sure you recognize that at the time, it's harder than a simple STA, you know, cortical MCA or whatever anastomosis. We've gotten into it.

It's similar, you know, I've done a bunch of it, occipital artery to PCA,

anastomosis. And, you know, I get used 110 usually and it's a little bit more finicky and I worry about the patency rate, that type of thing. But that's a great case. And I appreciate it. I'm

very curious when you do your delayed intro, your delayed angiography to see the degree of in growth and how much of it you feel is coming from your direct bypass and how much ends up coming from the,

from the Dura and from the indirect, I'll be very curious about this case. Please let me let me know what happens with it. I think those are great points and I completely agree that, you know,

it's a lot of work for maybe not the most long-term robust directory vascularization, especially with all the vascularized tissue we put on there. In this case, it was interesting. She was not the

easiest anesthetic and multiple times. You know, I was back and forth with the anesthesiologist and how she was a little fluctuating to with her pressure. So we were really trying to get through it

quickly And I had the same thought when I ended up looking at the post-op CTA. We had navigation and I thought I was a little bit more medial with that craniotomy. But I do think we irrigated, like

you said, certainly at least a watershed zone and having some help as it waterfalls over. Yeah, don't misinterpret constructive points as criticism. You know, I think these are great cases and

good job. Oh, no, thank you. I think that's the whole purpose we're trying to get people with experience and discuss what they would do. It's obvious there's not enough randomized studies to know

and I'm sure if they're ever going to be done well. So you're kind of going by the seat of your pants here trying to figure out the best thing to do. You guys did a reasonable job. I mean, that's

a very difficult situation and a reasonable job. You could put it a little in a position graft in there. That's another way to do it. But the more suture lines you have, the greater the risk of

having a problem in my experience.

So

I think you did fine. And just the angiogram is going to be extremely interesting. Yeah. Yeah, I agree with that. Let me see. You're right. I think a good takeaway from this discussion is that

certainly from an academic standpoint, seeing how the angiogram evolves with the direct versus indirect. We know when we look at six months. that there's a lot of indirect in-growth and presumably

decrease in some of the direct flow over time in patients, but I think that really document how that changed over time is important. So certainly we'll make that change. Did you use a flow probe in

this case? We typically do, in this case we did not, because I was really trying to get it done quickly. Yeah, it's a little harder to do in that location too, but it had been interesting to see

what the flow was I'm sure the flow over the hemisphere was good, but interhemispherical, it had to be really poor. I mean, that's a guess. Yeah, yeah, I would certainly agree. Okay, got

another case on anything. They were almost in this jumper time here, but good cases. This one is another interesting one that doesn't really fit the mold. And I have a PCA, or I have a vert

injection, so I'm glad I threw that in. So this is a 57 year old with a chronic left ICA occlusion She was sent to me by my partner who really didn't know what else to do for, or if we had options,

because she had progressive cognitive impairment despite being on medical management. So this is her left ICA occlusion. She does have some, it actually occluded down in the neck, and then she

does have some ECIC collateralization that it constitutes, and then just really trickles in here, but not great She has some filling through a patent PECOM into the ICA, which then fills out the

MCA, and then she does have a little bit of crossfilling from her ACA

territory, or sorry, through the ACA as well. Oh, she's 57, okay. Yeah, so you know, typically the typical patient we're treating these days has a perfusion deficit. I think that's a pretty

standard hallmark to say that they're flow dependent or they have, you know, some flow. issue. In this case, her her profusion was very unremarkable. And she had not had strokes. But her speech

and her speech was severely affected. And she did have progressive cognitive issues documented with mocha testing and with high level neurocognitive evaluations. So I was hesitant to offer

her anything. I really, you know, didn't think she had flow issues based on this picture. I saw her a few times and she had progressive issues and eventually in talking with my partners,

presenting her at our neurovascular conference, I went and up offering a bypass

and it grew in very well This is our six-month

picture here and you can see that STA really dilated up well and a significant portion of the MCA territory and I can't really explain it but she had essentially complete resolution of her cognitive

symptoms and whether this was placebo or what you know I don't know her certain you know the bypass is filling that MCA territory and the filling that you see from the vert injections and

cross-filling has nearly gone away

but this was an interesting case I really can't fully explain it. Well let me tell you some of the

earlier studies that were done in bypass and it's in the earlier literature which most people don't look at anymore but but there was a whole series of cases I'm sure Eric you'll remember this there

were a whole series of cases done with this quote cognitive impairment Rob and it was basically related to and people that bypasses on them and they approved and nobody

but I've seen it myself. And it's related to a vascular insufficiency to the brain. And she's telling you that because she's got speech trouble and she's got cognitive trouble. I mean, how else is

gonna demonstrate if it was further back and she's got a parisis. So it's brought a primarily frontal lobe. And

so I wouldn't discard, I think take your experience from this positively This can be part of the syndrome of cerebral ischemia. And maybe the studies aren't good enough to show you that. And I

don't know what your perfusion studies showed. But this, I've seen this, Eric, you've seen this before, haven't you?

Yeah, absolutely. I mean, I was gonna say sort of something similar. I mean, the problem here is that,

If you do this operation repeatedly for cognitive impairment, you will find some of the patients will get better. And it probably is more than placebo, but we don't really have an explanation. We

don't have a good way to select those patients out. The fact that she was younger is good. I think, you know, I mean, I would have been, if this had been a 75 year old patient, I mean, I might

have been kind of critical of you for doing the operation, but obviously the result speaks for itself And I think we've gotten kind of away from this because we've gotten beaten up by the controlled

trials and by, you know, reimbursement issues and challenges and challenges from the stroke neurology world or from the neurology world. But yeah, this doesn't bother me. I wrote a paper a number

of years ago on, I think we put together a series of patients who had longstanding neurologic deficit. that

was not expected to improve with bypass that resolved very quickly. And I think one of them had cognitive issues as part of the picture. I'm quite confident that it happens. Exactly what's going on

underlying when you can't prove a perfusion deficit. You know, I think it's harder to know. I also like the idea that she had speech trouble as part of it 'cause I think that that kind of makes you

feel a little more comfortable and just straight cognitive stuff.

But you would expect that we're gonna do better with these patients over time, you know, with the metabolic imaging and things like that, being able to differentiate between two forms of dementia

as opposed to, you know, something that increasing the perfusion might help. But anyway, I mean, we don't understand that, you know, there've been trials with some of the Alzheimer's patients

where people were putting shunts in them and some of them were getting better Like, why is that? I don't, you know, I'm not sure.

I agree with Dr. Osman. I mean, I would take it as a win and feel very good about it. Yeah, yeah, you know, we've started to look at cognitive outcomes post bypass. And I think, you know,

you mentioned from an overarching perspective, the criticisms of these trials and all of their outcomes were strokes or combination of stroke and death. But cognitive outcomes, I think, especially

in left-sided disease, no question if you really hone in on it and have the right population are gonna have a positive effect And this patient, I think, is a bit of a one-off without a perfusion

deficit. But for patients who really squarely fit the standard category of perfusion deficit, medically refractory, ischemic events, we've seen across the board and are starting to gather data and

present that data that cognitive improvement would almost be expected as a rule in these patients. Yeah, I'm just looking at this angiogram.

And there's a lot of stuff in this, Andrew. I'm gonna take the third picture in, which is the vertebral injection. And the vertebral injection shows this huge robust posterior communicating,

connecting with the internal carotid, right? And then you feel the mental cerebral. It goes pretty far out. Now, this is, I don't know where it is in your sequence, but it's going pretty far

out already. You're already up to the

end of the fissure there on the left side. And this is just filling from the vertebral, crossing over, filling, retrograde into the carotid, and then filling out in the hemisphere. You're asking

a lot. And then -

so I think the lady, this tells me, this lady's in trouble. And then you look at the right side, the next picture, next to it, or the right side of the opposite side It is robust. You see that,

I mean, the filling is, and you didn't do anything there, and it's robust, and it's seeing how she's filling, her interior is filling not only to the right hemisphere, but it's filling over to

the left hemisphere. So it tells me the indications are, is she is deficient in her flow, in her circulation, and her oxygenation to that left hemisphere. I think you did the right thing. I

think that was exactly right, and she got better because you probably corrected this would be interesting to see again what that integrant shows. Yeah, yeah. Well, so, yeah. And your bypass,

obviously, is working, it's robust, it's filling, it's filling down the middle, the middle cerebral group. So there's obviously other vessels that are being taken over there by collateral.

She's got something, I think, is that going through the orbit? The one in the second film, yeah. She offered - Oh, yeah, her collateral, exactly. proper external. So whenever I saw it going

through the orbit, that tells me she has got a tremendous demand and need for circulation. And so this lady is telling you in many different ways, she needs exactly what you guys did. I think you

did a good job. Yeah, next time, next time when you guys see

this, you're probably going to have the same reaction, which is your chance of triggering yourself to do this is your threshold is going to be lower. Yeah, and we have a protocol to, you know,

before and after these surgeries, we get mochas and cognitive evaluations to really start to understand how they're changing over time This is good. See, this is where the older literature has a

negative influence. You know, well, I'm going to see her in clinics or more and so forth and so on.

Uh, and I think going forward, you're going to operate on this patient earlier.

Yeah, and I think you're going to see these similar results and you had a terrific result with this girl. She has her speech was restored and everything else. Yes. Yeah, it was quite a remarkable

turnaround. And I counseled her extensively. I wouldn't necessarily have expected that, but we were quite pleased. Present that to neurology Yeah. No, exactly. They were following her and we're

similarly impressed. Yeah. So I think we spent about an hour here. Do you have anything else you wanted to show us? But I think we got a lot of good discussion here. And hopefully the people who

are watching this will learn a lot of things out of it. But did you have any other case you wanted to show? I don't have any other cases. I have a few slides on on posterior circulation, but we

can defer that, whatever you think. Well, what we could do on that is, why don't you go with that a little bit and then come back and. and show us some of your experience with that. We can

comment on that, okay? Okay, that'd be great. And congratulations to you and your associates. You're trying to be careful and do the right thing, but very good cases. I really wanna say

something.

No, look, I agree. I think that there's no doubt in the, I think in the mind of most probably experience fast-doing neurosurgeons that there are patients who benefit with ischemic disease from

revascularization. It's a matter of finding these patients and doing the operation well with low morbidity and obviously low mortality. And I'm still interested you can come back. You can talk

sometime about the Moi Moi experience if you're doing a lot of that, just because I'm seeing a lot of it and they're a heart, I find them to be a little bit of a harder patient population,

especially the young women. The children are fine. The children we do very well with I don't know why they're the young. You know, the 20, 30-year-old women who are very symptomatic, who've had

numerous ischemic events before, I find harder to manage, so I'm just curious. But yeah, in a perioperative period, do you mean? Perioperative, yeah, yeah. Yeah, we probably do about 60, 40,

atherosclerotic or steno-clusive disease versus muy amoia, just for whatever the population is here.

But I would say we've had similar outcomes with both. I personally haven't seen too much of a difference

as far as the perioperative issues with muy amoia. We certainly have seen people especially left-sided bypasses have fluctuating symptoms in the first week to two weeks post-operatively and we'll get

a full workup and there won't be a stroke, Right. Hemorrhage and then it just is, you know, a period of time where that brain is getting used to the flow. And that probably happens maybe a little

bit more in the more and more if that's what you're talking about. I think that's probably more what I'm talking about. But yeah, it's a great experience, good job. Well, thank you both. I

really appreciate the time. Okay, that's terrific. Did

you ever have to talk to Fadi about his flow measurements? I know he did a lot of work on it, it was very good

And actually, I think it was very threatening to the neurologist, did you ever talk to him about that? He had a company, sold it to somebody, and I don't think much happened with it, but it was

a really good use of intraoperative flow and they could take it down to various segments of the middle cerebral and, as you know, anterior and the different vessels, and you could get flow rates.

And you could see it before and after surgery I thought it was a terrific idea and that's not the whole answer either. because not only you have to get blood there, but you've got to get all the

nutrients and the oxygen and so forth. And I think the fact that you guys are doing these cases, your mortality is extremely low. It means you're paying attention to all the details. I was just,

I just do not see a 90 morbidity

mortality. I just, I don't, I don't get that. It makes no sense to me. And you've got to pay attention to all those details, you guys are, you took a high risk guy, you were very careful, you

had a good result. That should happen. Yeah, yeah, I agree with that. And we've used, I don't know if we use the probe that you're talking about, but we have the Charbell flow probe here,

which is, just tells you, mils per minute. We did it, we did it by MR. It was an happy MR. Oh, yeah, yeah, I'm familiar with that, yeah. And I don't know what happened to it, but that is,

since you guys have a lot of volume, that would be worthwhile. if it's around and it's still valuable. That's what we need.

Because you're gonna find out that segmentally the perfusions are not exactly what you think, nor are the flows. And it's gonna become very important in the post-year circulation that you're getting

into. Yeah, to try to match that or replace what you need exactly. Okay, Rob, we appreciate it. Thanks very much, Eric. Thanks for all your time. Thanks, Jim And

come back,

and we can do some more of this, okay? I look forward to it, I really appreciate it. Okay, thank you. Thanks, have a great day. Yeah.

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Young Neurosurgeons Discussions with the Experts; EC-IC Bypass Surgery 1980-2025

James I. Ausman, MD, MA, PhD

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