So, please interrupt me if you have questions during this. This is for you, after all, so I'd rather that you stop me and we have a little more interaction than I just keep barreling through these. So, a couple points to begin. It's an important technical skill, this bypass technique that Peter began speaking about. It doesn't matter what you're going to do, whether it's tumor surgery, vascular surgery, you're going to need to feel comfortable around arteries, and if you feel like you can repair an artery, it will give you that level of comfort that will give you confidence. And so, I think it's worth developing. A couple things that are important, just to highlight the need for bypass, in looking at my giant aneurysm series, what I found is I'm doing more and more indirect aneurysm occlusion, less direct aneurysm occlusion, which means more and more bypass. So, as we've moved towards more endovascular therapy and less hypothermic circulatory arrest for these lesions, you really see less and less direct clipping and more and more of this indirect. So, it really plays a role for cases like this one where you're going to do a flow shift by a bypass and a proximal or distal occlusion or a trapping. So, giant aneurysms, more and more. And the other thing is that, and this is really meaningful to me, I've tried to move away from traditional ECIC bypass because I think these intracranial bypasses, the ones that are more reconstructive, that use brain vessels rather than scalp arteries, tend to be more satisfying and a little bit more technically challenging, but more user-friendly in the sense that you're not harvesting, doing a lot of extra work to harvest a temporal artery or an occipital artery, but just bringing in the arteries that are right there anyway. And this is an example of different in-situ techniques for middle cerebral aneurysms. I'm going to take you through this in detail, so we'll spend some more time going through that. So, here's some statistics from my practice in San Francisco. And a lot of aneurysms, but what you see most importantly is that only about 4% end up needing a bypass. So, you could say, well, why do we spend all this time in this lab or in these lectures talking about bypass if it's only 4%? The answer is that you just never know from this number where this number's going to come from. And you always have to have that ready to go as a contingency plan. You go into many of these cases thinking that you're going to clip, but sometimes things tear or the anatomy isn't as you anticipated on the angiogram. And so, usually in those situations, the contingency plan involves a bypass. So, even though it's only 4% in reality, I end up thinking about these maybe in about 20% of the aneurysms that I evaluate. So, in terms of this idea of arterial reconstruction rather than ECIC bypass, this is how I think about it. I think about four different techniques. The in situ bypass here is a side to side connection. It brings two arteries together with a side to side connection so that you can preserve the integrity of the donor artery. So, if you have a side to side anastomosis, it doesn't matter that you're donating or borrowing flow from that because you're preserving both inflow and outflow. So, it's a very nice way to reconstruct an artery. Reanastomosis is also very elegant. It's what's shown here, bringing things together end to end. The problem is that it's only useful for some aneurysms because very few aneurysms actually are just one inflow and one outflow. So, as nice as that is and as quick as that is, it's not as frequent as we would like. Bifurcation is like your classic STA-MCA bypass where it's an end to side connection. So, this is a very easy translation from what you've seen and probably learned and I'll show you how useful it is. It's a great way to rebuild a bifurcation or a trifurcation or what have you because it gives you a lot of options. And finally, interposition graphs are helpful if you're trying to do an intracranial bypass but you just don't have enough length of artery to work with. So, you have to bring flow from a donor that's a little bit further away with a short segment. So, those are the four different techniques, the three different types of anastomosis. And there really are four good sites that you can use for these techniques. The sylvian fissure obviously, a lot of vessels there and a lot of space to work in. The interhemispheric fissure is nice because if you position the head and allow gravity retraction to do its thing, you can really open that up. The carotid cisterns and the crural cisterns down at the basilar apex get deeper. So, they're a little harder but you have some space and you have some options there. And the cisterna magnet, really a great spot to do bypasses and for the pica bypasses that Peter just showed you, really is a nice working area. So, let's start with the insitus. As I mentioned, it's a side-to-side anastomosis. It preserves flow in the donor. What makes it a little bit more tricky is this intraluminal suture technique, which you have to do. But what you gain by doing that is that you're not having to move arteries around in the way that you do, say, an STM bypass where you flip things from one side to the other. With this, you're just leaving things as they are and your suturing techniques kind of work around the space. I'll talk about this reversal stitch in a video and that's that no mobilization of the donor, which is really important. So, here's a case. This is an endoscopic pituitary adenoma resection that went bad at an outside hospital. This was done with limited view and they got into a perforator, I imagine, had some bleeding, had a perforator infarction. And if you look right here, what you see is this P1 segment dissection. So that P1 segment was injured by probably the ronger, the pituitary ronger, and you can see the result. If you think about your endovascular options, really the only one is a takedown. There's no other way to deal with that pathology. And if you did that, you would risk, I think, an occipital infarct. So the bypass option for this would be an SCA-PCA bypass. This shows you how SCA below and PCA above, which I'm cutting there, lie in parallel to one another. So they're perfectly matched for this side-to-side connection. To do this bypass, what you need is two arteriotomies and then you sew the arteries together. And then this suture line, this first suture line, is between the two outer layers, sewing the two inner layers together, and it's a running continuous suture. You can practice this downstairs with your turkey wings, but basically, you're just bringing these two parallel vessels together. This is that reversal stitch to bring the needle from the inside, the interluminal side, to the outside, and then you can tie it to the other suture. This now is the outer suture layer. You bring those two outer layers back over the top, and it's just a running continuous again. There's no interluminal suturing for this one. This is all extra-luminal. But there you have the completed anastomosis. And this next zoom-out shows you the depth. You're really pre-temporal, all the way at the ambient cistern, tentorial incisura. So it's a good six to eight centimeters deep. It's about as deep as you can go. But on this icy green, you can see a nice connection between SCA and PCA. And now, with that in place, now we can deal with the aneurysm. You can see the pseudoaneurysm here, and it's so fragile that just a little bit of lift here is going to cause it to rupture. This is the basilar trunk here. So there it goes. It starts to bleed. We've got our proximal control here on the basilar trunk, so it's very easy to deal with that bleeding. And with that control, we can trap the pseudoaneurysm. So that first clip is proximal P1. Second clip is distal P1. And now that dissection is closed completely. And thank goodness we put the bypass in first, because if not, you'd be doing that bypass under duress with ischemia time. So here's our connection. You can see SCA now feeds the PCA, and it also continues on to supply the rest of the SCA. So there's your trapping. There's your bypass. It's all done right in close proximity, and it's a very nice way for a very difficult problem that if left to the endovascular team, they would just have taken down the PCA. So that's an example of the in situ bypass. And here's the result. You can see on the postoperative angiogram, P1's gone here, but if you look here, P1's filling out very nicely through this donated flow from the SCA. So that's in situ. And I really like that bypass. It's really a nice way to go, because you frequently will find these arteries in parallel. You can find them at pica. The caudal loops of pica are parallel just like that. You can find it with the PCA, the SCA. You find it in the ACAs over the corpus callosum, because the ACAs run right and left parallel to one another. And where else do you find it? MCA. So the sylvian arteries are also right next to each other. So really, there are a lot of opportunities for that in situ bypass. Now reimplantation is the next one I want to talk about. This is the end to side. This is the one that's analogous to the STA, MCA. You preserve the flow in your donor. So when you reimplant your recipient, you're not taking away from the donor, but the recipient really is a transected artery that's got to be moved. So you're really taking one vessel off of an aneurysm and revascularizing it directly. So that's really what this is about. It does require that you mobilize the implanted artery. If you're taking down a pica from the aneurysm, you've got to make sure you can drag it over to the vert, for example. And that's not always possible, so you have to inspect that and make those decisions. The other nice thing about this is that you have the option for multiple reimplantations. So for example, if you've got an MCA that you're rebuilding and it's got two arteries coming off, you can do two reimplantations, not just one. So it gives you the option for a double or a triple reimplantation. So it's a very good, versatile, reconstructive technique. These are those triangles that I've spent a lot of time thinking about and trying to define for people, because as we just talked about in that last lecture, there's a lot of morbidity that comes with working around 10 and 12, and not so much 11, but 10 and 12 primarily. Patients have trouble swallowing, they get aspiration complications, they get really sick and can die. So you really have to deal with those two nerves really carefully and delicately. What always helps for me is to think about triangles, anatomical triangles. So this one is very important, this Vago accessory triangle, defined by medulla, vagus nerve, and accessory nerve. So this is that Vago accessory triangle, and that's your working window for pica aneurysms. The 11th nerve runs right along the dura and the skull base, so it's really plastered against the skull base and doesn't allow you to get much in front. The medulla behind you, you can't get any further than that, and 10 defines the upper limit. So this is really the space that you have as your kind of working arena. And if you think about the 12th nerve, the 12th nerve comes off from the preolivary sulcus in front and deeper to these other nerves, and it bisects that triangular space into this infra-hypoglossal triangle and this super-hypoglossal triangle. And you'll find aneurysms that are in all of these different spaces. They could be super-hypoglossal, infra-hypoglossal, they can be, sorry, under the 12th nerve, and they can be completely outside of the Vago accessory triangle. So it's helpful to think about where you are, how deep you need to go, and what's going to be your working space. As you define those things for yourself in your mind's eye, you can then, I think, be a little bit more delicate with the nerve. All that being said, this is to demonstrate the re-implantation, which moves it from the super-hypoglossal to the infra-hypoglossal triangle. Here's the aneurysm. It's calcified, un-clippable. There's really no way to clip that. So this is going to require this re-implantation. This is the view with the far lateral approach. Your 11th nerve is your orienting nerve running up here. This is your vertebral artery. This is all aneurysm here, and this is pica coming off. So as we inspect this, what you see is that dentate ligament. We can cut that, get some more exposure of the vert, which is right underneath always. So here's the vert, that V4 segment proximate. This is all aneurysm down here. And that's going to be our landing zone for the pica re-implant. This really comes off the base of the aneurysm, and that clip there is basically to occlude it and allow us to transect it. Here we've trapped the pica origin. Now I'm transecting, and there's enough mobility usually with pica because it's so tortuous that you can free it up from the aneurysm and drag it up to the vertebral artery. So this is the maneuver for the re-implantation. We're essentially taking it off the aneurysm. We're trapping that segment of the V4 proximally, and we're making an arteriotomy. So here's our arteriotomy in the vert, and that's going to be our donor site. The pica now, you can see, has a lot of redundancy, a lot of mobility. So we can move it up to the vertebral artery. And just like the STA when we do a traditional bypass, I like to cut it at 45 degrees, cut an extension down the axis of the artery just to widen as much as possible that opening. So instead of just a circular transection, we've actually cobra or fish mouth this thing, so it's like a cobra head. So the suturing here is all extra-luminally. It's two knots at either end, and then running continuous sutures from one end to the other. And what I do, and what you'll practice downstairs, is place all of the throws first, and then go back through from the first throw all the way to the last throw and just tighten it up. And here you can see that unlike the in-site to where everything stayed kind of fixed, you have to move the artery from one side to the other. So that first suture line, you move everything to the left. For the second suture line, you move everything to the right. And so it does require that mobility, which you don't always have the luxury of. But there's the postoperative angiogram. The pica's now feeling offered, and we've re-implanted that. So that demonstrates the re-implantation. And that's pica. You know, you can see how you can move through the triangles to get that done. But you can do that in the Sylvian-Fisher for MCA aneurysms. You can take a frontal or temporal trunk off of an aneurysm and move it to the other one, the other trunk, or to the proximal M1, a variety of options there. You can do re-implantations on the ACA, and I think I might have a picture of that. Yeah. Here's a pericallosal re-implantation. So looking at this aneurysm, here's a thrombotic, large aneurysm. Here it is angiographically. You can see this would be a tough neck to reconstruct because the flow kind of comes in and works its way around. So this is our pericallosal here. This is our callosomarginal going over the cingulate gyrus here. And when you look at the interhemispheric Fisher, you can see how things lay out there. And at surgery, what I like to do for these to increase the space is to turn the head, instead of nose up, nose to the side, so the midline is horizontal. So the way we're looking at this here, the phalx and the midline is this direction. So here's your midline plane. This is gravity retracting the dependent hemisphere. Here's the inflow artery. Here's the aneurysm. Here's the pericallosal. And here's the callosomarginal. So the idea here is that we're going to take this artery off of the aneurysm and we're going to drag it up to the callosomarginal up here. So here it's transected. Here's the arteriotomized callosomarginal. And here's our suture line. In this case, because there wasn't a whole lot of mobility, I sewed this suture line interluminally, like I do for the in situ bypasses. And here's the second suture line. But it's the same technique, running continuous, and we've got that re-implanted. And you can see here, after you've re-implanted, the aneurysm can be trapped. So it looks like this. That does require mobilization from on top of the corpus callosum under the cingulate gyrus to above the cingulate gyrus up here. So you have to have a little bit of freedom of the arteries to get that done. You can do that other sites as well. You can do that, I've done it at the carotid cistern, taking the temporal artery off of the MCA and dragging it down to the SCA for a complex SCA aneurysm. So that's another form of re-implantation. I showed you the pica. So those are the different ways that you can do that. Okay. Re-anastomosis. So let me go back. This one now is the third variation. This is now end to end anastomosis. So it requires splicing out the aneurysmal segment, bringing the two ends together. Usually requires that there be a one-to-one match. You can do a one-to-two match. It's much more challenging, but you can do that as well. Requires some redundancy, meaning that if you've got a long segment, like a giant aneurysm that you're excising, it may be difficult to bring those ends together. And if you have too much tension, there's a point of diminishing return where if it's too tight, you're going to pull your sutures through or you're not going to get the arteries together. So you have to have that. So there is some art in selecting how you're going to choose this. And better with smaller fusiform aneurysms because of those concerns. So this is an example of a giant MCA. You can see here, a lot of thrombus in this, a lot of edema around it. It primarily involves the M1 segment so that we'll have good vessels to work with. This is the sylvian fissure. The frontal lobe is here. The temporal lobe is here. These are the veins distally in the fissure. And this is all giant thrombotic aneurysm. This is our inflow. This is our outflow here. And you can see how adherent this is. And really, the disease segment goes from here to here. So it'd be real nice to bring those together. But in order to create that redundancy, that mobility, the first step in this case was to go in with a CUSA and just debulk the aneurysm. If you take out some of that mass and reduce that tumor mass to basically a sac, then it'll free up those ends so that there's some ability to bring them together. So that's what I've been doing here. I've been just taking out thrombus, cutting down the aneurysm. And at the end of it all, these ends of artery now are free. So here is the transected proximal end. And that other distal end just flashed by. There it is. Distal end here. You can see the M1 is nice because it's got a lot of muscular tissue in the wall. So you've got some meat to hold on to. And these pull together very nicely. The nice thing about end-to-end reanastomosis is there's usually perfect caliber match between one end and the other. The techniques are identical. One suture at one end at 12 o'clock, the other at the other end at six o'clock. And then the bites are basically circumferential, going from one knot to the other. So, unlike the other anastomosis, where I try and get the arteriotomy to be at least twice to three times the diameter of the artery, here it's simply the diameter of the artery. So, there are fewer bites. You'll notice in these, there may be six bites or so. The other anastomosis are about a dozen bites. So, this ends up being a faster, I think, quicker, usually easier bypass than some of the others. The M1s can be a little bit larger than, say, PICA or others. So, I think in this case, there may be more than six bites. But you can see that you just go from one end, one knot to the other knot, placing these loops of suture. And then at the end, once they're in place, then you have to go back and tighten them up. The advantage of this technique, rather than the interrupted technique, is that you essentially tie four knots, not 24 knots or whatever it is. And so, it's faster. Here's the third knot being tied. And so, you've got your suture line completed. Now, to get to the other suture line, you have to roll things the other way. So, there's got to be a little bit of roll to the vessels to bring the two suture lines into view. And you can see how moving the clips downwards, the other direction, brings that back wall up more superficially. And that allows you to place these bites in the second back wall. So, there it is. There's your completed anastomosis. It's end-to-end. It's a splicing out of the aneurysm, essentially. And it's a very beautiful way to reconstruct that. Endosigning shows good flow across the bypass there. The trunks coming off the M2 segments. And there's our gutted aneurysm right there. So, Sylvian Fish was a beautiful spot to work with for really any of the different bypass techniques. But, particularly that M1 segment is really nice because it's meaty. Let me show you this one. Because this one shows a lot of different things. It shows, number one, how you go into a case with one plan and it doesn't always work out. And when things don't work out, usually the bailout option is a bypass. Second thing it shows you is that you never know how you're going to get arteries together. You have to have all these different variations of technique ready to go. And so, in this case, I'll show you my thinking on this one. This looked relatively... For a bypass, does it take the time to bypass? For you, it takes a long time. So, this aneurysm looked to be pretty accessible in the distal fissure. And my thought was to come in here, try and clip reconstruct one of these junctions here, and then bypass the other one. So, this looked to me like just a classic bifurcated trunk distally. And the idea was to then figure out which of the... Find one of these arteries. I think this was the one that I had chosen because it's bigger than this one. Find this one on the cortical surface, do an STAMCA bypass, and then go down to the aneurysm and do a reconstructive clipping that just goes from one, from the inflow to the other outflow. That was the plan. I think you can see it a little bit better here. There are two. There's one outflow there and... Yeah, maybe the other outflow is here. But in any event, it was a bifurcated anatomy and I was going to bypass one and clip to reconstruct the other. So, here is the STAMCA bypass. And you can see that there's good flow. Here's the recipient. The anastomosis is open. So, everything looks good. So, now I'm down in the deep insular area. I've got the aneurysm trapped. And in working this, I've transected the aneurysm. There's the inflow and I've torn it. You can see this is bad tissue and I've torn the base of the aneurysm from the afferent artery. This is now the inside of the lumen. And so now, I really can't do that clip reconstruction from inflow to the outflow. And so, what I'm doing instead here is I've taken the afferent and I'm bringing it to that other efferent. So, this is an end-to-end connection. So, I think, okay, I've dealt with that problem with the bypass. But now, here's the icy green. You can see it's not patent. And now, when I go back up here and I look at my STA, that's not looking very patent to me either. So, I've got two occluded bypasses. And so, I'm more concerned about the angular artery. So, I've taken this from the aneurysm and I'm bringing that together with the afferent, the inflow, end-to-end. So, my thought is I'm just going to salvage the bigger of the two outflow vessels using this inflow with an end-to-end. So, there's that. And now, this looks good. I've got that saved. And so, now, I'm just kind of reviewing my options here, trying to think how I can save this thing. And so, I decided to go for broke and use the afferent also for an end-to-side reimplantation. So, this is end-to-end. This is end-to-side reimplantation. And I'm going to bring this second trunk together with this outflow artery. Okay, and here it is. Now, it's a T bifurcation. Here's the donor. This is the one trunk here, the second trunk here. And you can see everything fills now. There's some spasm here in this artery because it's been manipulated. But we've essentially dug ourself out of a deep hole with both a reanastomosis and a reimplantation, both of which were unexpected. So, that's just to make that point that, remember that 4% number I was talking about? You just don't know in many of these cases whether you're going to need it or not. No, no. Had a small CT finding of some edema around the aneurysm. So, but most of that cleared. There might have been a little bit of an infarct, but not clinically apparent at follow-up. So, lastly are the intracranial graphs. And I should say that I think that area does have some, enough collateral to get you through that window, that ischemic window of your bypass. You have to view it almost as if, you know, you've got an MCA embolus and you've got that three-hour time window. Kind of view it the same way. Sometimes, you know, you think, my gosh, you know, I've kept this artery occluded for 45 minutes. How are they ever going to not have a stroke and not have a deficit? But if you kind of stand back and think about what we do for embolectomy, you've got to think of it in those terms. There's usually enough penumbra and collateral to the penumbra to kind of get you through that short-term window, particularly in the setting of an interoperative event where you can put the patient in burst suppression, you can raise the blood pressure, you can do things that will get you through. So, lastly, the intracranial graphs. Now, these are a little bit more complicated because it's two anastomoses rather than one. It can be any of the different variations, end-to-side, side-to-side, what have you. It's a little harder because you have to get a graft. The radial artery is usually perfect because size is well-matched and the length needs are usually small or short, so it usually is sufficient. And sometimes, all you need is like five centimeters, which can be harvested very quickly. So, it's a great source for that. Let me show you this case. This is a subarachnoid hemorrhage patient and if you look very carefully, what you see is just this dissected segment of the A1 from the carotid terminus all the way out to the acom. And if you look here, you can see that disease segment. If you also notice here, there's no contralateral A1. So, this patient's ACA territory is completely dependent on the right A1. So, you can't just go in and endovascular occlude that. And the ACA is very poorly collateralized distally. So, this took some thought and the thought was that we would do a graft from the MCA. So, I would use one of these donors here and bring this over to the acom. Now, the other thing is that normally I sew the deepest, hardest end of a graft in first and save the easier part for later. And so, normally that means sewing this in first, but if you think about it, you'd have to close your A1, do that anastomosis, and then do your second anastomosis to the MCA. So, you have two periods of ischemia when you're doing each of the two anastomosis. So, in this case, the thinking was to first, well, to reverse that and sew in the donor site first and then bring it up to the recipient site second. So, it meant sewing the harder bypass end second. Make sense? So, this is that view. You're now looking at the dissected segment. This is the ACOM here. So, carotid is here, the terminus is here. And you'll see that as I transect the A1 segment, it's completely dissected and diseased. This is, well, this is the distal stump of A1. And I kept having to cut back to get normal tissue, taking me almost all the way to the ACOM. And in this case, the lady, she was a smoker, she was morbidly obese, so I could not use her radial artery. It was too diseased. This is a saphenous vein. And I've already sewn in the MCA, which I haven't shown you. But now, this is the saphenous vein graft. This is the stump distally of the A1. And this is now just that first connection to bring them together. And so, what you'll notice here is that this is about yea big, and this is about twice as big. So, there's a tremendous mismatch between the saphenous vein and the distal A1. You'll also notice that I'm doing interluminal suturing because it's really hard for me to kind of see around this tight window. And so, that complicates it as well. So, you just never know what it's going to take. But in this particular case, it took interluminal suturing despite the fact that this is an end-to-end, and usually I don't do that. The other thing I'm doing here is I'm sewing both suture lines towards myself. So, now this extraluminal suture line is from the top down. You can see all the bites here along the way. And I wasn't quite able to get rid of the redundancy, so it takes a little clip there to just take off that little tag of extra tissue that I couldn't incorporate in the suture line. But now, as we take off the clips, the bypass fills, I had to clip the AECOM itself to get enough room on the distal A1 stump because there was so little of it. But here we're going from sylveon fissure out to the AECOM through this large saphenous vein graft, and you can see nice filling out of the ACA territory. So, that's an example of an intracranial graft. There are many, many examples. I just chose this one, but we use these grafts in the interhemispheric fissure for complicated AECOMs. You can use it down to the basilar apex for a trunk aneurysm. You can use the VERT to vertebral artery or to pica for a pica aneurysm. Really, a lot of options there. Here's her postoperative angiograft. Here's her postoperative angiogram, and she recovered well. So, these are just some summary slides showing the four different techniques in the four different sites. So, we've got in situ here using the anterior temporal artery as a donor. We've got reanastomosis, which I showed you. Here's a reimplantation of a temporal trunk to a frontal trunk, and here's a bypass graft from the A1 to the superior trunk. So, those are MCA options. ACA options are shown here. Again, the four different variations. Here are the pica variations, the caudal loops of pica coming together as a pica to pica. Here's a reanastomosis. Here's the reimplantation, which I showed you, and here's that vertebral artery to pica. And then, lastly, the basilar. These are the hardest ones. I showed you this one, pica to SCA, or sorry, PCA to SCA. I didn't show you this one. I didn't show you this one, but here's that anterior temporal artery that's reimplanted to SCA as a donor. So, that's a donor reimplantation rather than a recipient reimplantation. Yeah? I was gonna ask if you could go through your thought process a little bit on selecting a donor and potentially longevity of the graft after site selections. Radial arterial versus saphenous and that sort of thing. Yeah, so, very few of our grafts have occluded long-term. We have not imaged all of them. In the ones that we've imaged, which is probably more than 50, we've only had one occlusion, but we're trying to get these patients back for a reasonable review and being analytical about it. So, the grafts, I think, are patent. I think radial artery stands a longer, better chance of remaining patent than the saphenous vein because it's matched in caliber. It's arterial, not venous. It doesn't have valves. It has just, I think, a better likelihood of staying open. And it's shorter. If you're using a radial artery, it usually means that you're doing a short-segment graft. So, I don't think you need to worry about long-term patency. You do have to worry about patency short-term, meaning that the ones that we have had occlusions usually go down in the first 24 hours. So, if something's going to happen, you'll either know it at surgery and you should fix it right then and there or, you know, get your immediate post-operative angiogram and deal with anything that's happened right then. If you get through that first 24-hour window, I think you're fine. I think your second question was, how do you pick amongst the many selections? Well, I think that's what I've been trying to impress upon you. You don't always know until you get there. And it may depend on whether there's one inflow and one outflow, in which case the excisionary anastomosis might be best. It may depend on the redundancy of the tissues, meaning that if there's a lot of redundancy and you can pull things together, you've got that option. If you don't have that option, you think of your four other choices and pull one of those out. The thought, the idea is that in surgery, when you've got a problem, there are too many things going on in your head. You've got the, you know, like that case I showed you, if you're anxious about that bypass occluding or you're, you know, you're feeling the stress of your temporary eclipse or your, you know, your OR team is a little frenzied, you may not think of an option that's there right for you. So if you just remember the four different variations, you can just say, stop, let me go through each one of these four things and think, all right, is there a re-anastomosis option? Is there an in situ option? Is there some graft option? You can kind of methodically work your way through to sort of keep yourself focused on your options. And then it's just a matter of, you know, addressing, you know, are you able to get those arteries together? Are you able to harvest a radial artery? Is there a re-implantation option with a good donor vessel nearby? So that's really what I do. Sometimes you end up with multiple good options. Like last week we had a case that I could have either, it was a pica aneurysm. I could have either re-implanted it on the vertebral artery or I could have done a pica to pica. And I just looked him over and I said, you know, I don't want to involve the other pica if I can just work on one pica, so I'm going to try and re-implant this rather than do a pica to pica. And that was my thought process for that case. Other times I think, well, you know, this re-implantation looks a little bit more difficult because I'm too close to 12 and I don't want to get a 12th nerve palsy. So I do a pica to pica. You know, it's just, I think it's a gut feel at the time. Other questions? Yeah. Yeah. Whenever you think about it, my rule of thumb is if I've thought about it, prep it out. Because if you think about it and you don't prep it out, not only will you kick yourself, but it usually means that you're going to need it. It's when you prep it and have everything ready that you don't need it. And I think that, you know, I've planned for hundreds of bypasses. I've only done, you know, 138 or whatever that slide says. So, you know, you have to be prepared and ready way more frequently than you actually use it. And I love to do bypasses. You know, it's one of my favorite operations. They're challenging. They're creative. They're very elegant. But inside of myself, I only like to really do them when I have to do them. I don't want to do unnecessary work and I don't want to take a risk that might backfire. So you really have to prepare and plan for these things, both mentally and physically in the OR as you get your radial artery site ready. But you really want to have a reluctance to actually pull the trigger because, you know, a clipping option is much faster. And a clipping option is, you know, I think often less risky. So it's preferable. But you can see the numbers. This is a big number. I think we're up to about 170 or so now. And this slide is just to impress upon you that pretty much all of these cells are full with this exception. And these numbers are even bigger now. But you use all of this stuff. If you think about it, you'll use it. And if you have the skill level, you'll use it. So you should get down into the lab this afternoon and really practice, ask questions, develop your competencies, and when you get home, practice and develop your competencies. These are not things that you develop in three hours in a course. You really have to spend... Well, I can tell you in my case, I spent a year doing research that required a lot of these techniques as part of the animal model I was using. So I did hundreds of bypasses as a resident. And that's where it came from for me. And I work with my residents. I encourage them to spend time in the lab. And that's where it comes from for them when they do develop it. And for guys like Dr. Rina, who never developed these skills, he never does these as part of his practice anymore. And so I'm sure it must bother him to see me doing these great cases like this. I'm just kidding. I love Howard. So you've got to take these comments with a grain of salt. So in summary, I think we're moving away from ECIC bypass. We're moving towards arterial reconstruction. I think that's the way to think about this. Think about your ECIC options and have those in your back pocket. But remember these because there are many more options here, and I think they're a lot easier to work with. To harvest an occipital artery takes about an hour, and it's a pain in the neck. A pike-at-a-pike bypass, if you decide to do that, takes two minutes. You just mobilize the vessel, pull it over, and you can start suturing. So remember these things. We've published on this, so if you don't believe what I'm telling you, you can read about some of our results in more detail. But I think here's the key. Spend some time. Commit some of your free time to practicing. You can do it in turkey wings in your living room. It doesn't really require that you have a course like this. You can just go to the supermarket, grab a suture and a needle holder, and really practice these things on your own.

neurosurgeon

bypass surgery

vascular surgeries

giant aneurysms

endovascular therapies

intracranial bypasses

arterial reconstruction

sylvian fissure