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Grand Rounds-Bypass Techniques for Complex Intracranial Aneurysms

Jacques Morcos

December 15, 2012

Transcript

- Hello folks, thanks for joining us again. Today we have a special guest, Dr. Jacques Morcos from University of Miami. He's one of the most amazing teachers and superb surgeons I've ever worked with. He's gonna talk to us about techniques for complex bypass procedures especially related to cerebral aneurysms. He's gonna start his talk with a series of slides followed by three detailed videos. Jacques, thanks again for joining us and please go ahead.

- Thank you, Adam. Again, it's a wonderful pleasure to join you for this webinar this evening. And I will be talking about bypass techniques for complex aneurysms. As Adam you well know you and I did the webinar before discussing bypass technique for STMCA aneurysm in which I discussed general principles of bypass surgery, which I will not repeat here. So I will carry it from here onwards. I'd like to remind people that there are several types of bypass. I put this table together to try to summarize all the types of bypasses one can create, and you can see that's a two by three table. If on the left, we write down the type of donor we're using. And in the columns section, we put the number of anastomosis, either one or more than one, we can categorize really all existing bypasses. And you can see here, I will not go in each detail that they can be inside two bypasses, short grafts, long grafts, and the STA-MCA or occipital artery to PICA. Here of course, there is no such bypass because you cannot create a bypass from a distant extracranial donor site with only one anastomosis. So tonight I will show three videos, one for In-Situ, one for short graft, and one for long graft bypass. These grafts, as we all know, the STA is the most versatile donor we can have. It is not always low flow, it can be quite high flow and low flow, designation is a misnomer, you can use it for double barrel bypasses. The saphenous vein graft is excellent conduit, there is an issue of the valves in the vein. That is an issue, whether you keep it In-Situ, or whether you reverse the graft. When I use it, I do not reverse, I do not create a valvotomy, I keep the valves In-Situ so as not to disrupt the endothelium, and I generally have it taken endoscopically from the thyroid and make a long incision. But the long-term patency of vein bypasses is definitely slightly lower than the radial artery bypasses here, which are generally medium in size. They are the ideal caliber match and suturability of most intracranial vessels, but they are limited in length to about 23 centimeter. And you have to certainly do an Allen test to document that they are not essential to the circulation of the hand. They can go into spasm post-op, and of course there is a forearm scar. How do we tunnel grafts? I generally use preauricular subcutaneous tunnel using 28 French chest tube using the blunt end of the chest first to avoid seventh nerve peripheral injury at the parotid gland. I don't like the post oracular tunneling. And I generally don't use the trans-middle fossa floor, the tunneling, and of course the bonnet contralateral bypass is very rare scenario. Which anastomosis to do first, generally the intracranial anastomosis is best done first. That's usually the more difficult of the two and the limiting one to the length of the graft. And generally when one more than one anastomosis is done, it is essential to strategize so that the least ischemia is incurred on the intercranial circulation. There are lots of details about the geometry, the angulation, the conformality of an anastomosis. Again, too many details to discuss in this present webinar, but suffice it to say that the end to side is usually the easiest, the end to end is more prone to stenosis. The site to site bypass is generally the hardest, the side-to-side is generally done in a PICA to PICA or an A3 to A3 bypass. I generally prefer to angulate the bypass at about 45 degrees, rather than a 90 degree angulation. It is more physiologic and it will direct the flow in one direction. Of course, it's important to get a large cross-sectional area and to achieve what's called this elephant foot design, when you do an end to side anastomosis. Use of instruments, I generally favor curved needle holders to add one degree of freedom to the wrist movement. I generally prefer 3/8 of a circle of a suture needle, it is better than half a circle. Again, it allows you more control of your suturing. I generally use small needle BV or a V 70-3 from the ethilon variety for the small bypasses. And for larger conduit, like a vein, I would use a BV 130-5, for saphenous vein graft. A 10-0 is generally for an STA-MCA or an IC-IC bypass. An 8-0 is when a vein is involved, generally a 7-0 in the neck for the common carotid or the ECA external carotid artery. And I generally prefer ethilon rather than proline although I do use proline in the neck. So let's just quick examples of long grafts, a saphenous vein. This is how we take endoscopically, the saphenous vein from the thigh. This is a physician assistant from the cardiothoracic unit. These are the endoscopic equipments to take the saphenous vein. And this is a view you get with an endoscope in the thigh and you strip the vein, and of course you have to tie the side branches on the back table. Radial artery, an example of use of radial artery in this giant vertebrobasilar dolichoectatic aneurysm. You can see it's partially thrombosed as most of them are. The patient had no good posterior communicating arteries. Here is a radial artery taken from the forearm. Here is a radial artery going through a subtemporal approach. With self retaining retractors the radial artery goes into side to the P3. This is direction of flow in the PCA, this is an anastomosis completed. And by the way, these numbers that are in blue boxes, as you might see throughout the talk relate to CC per minute of flow measured after the anastomosis. This is an excellent flow, more than 40 CC per minute through the graft, and this is now tunneling the graft down to the neck where it's sutured and to site to the common carotid artery, so there is a completed anastomosis, and that is a op a CTA showing a patent anastomosis. So radial artery is really ideal for posterior circulation bypasses. The aneurysm thrombosing four months post-op and there is an angiogram documenting the nice radial artery conduit. And we occluded the vertebral artery with coil occlusion at the time. And there is another view of the CTA. Another category as we said is In-Situ and short grafts. In-Situ and short grafts can be used in anterior or posterior circulation. I'll show a little bit an anterior circulation example, the ideal In-Situ reconstruction of this unclipable aneurysm. It was very calcified and partially thrombosed and the neck was calcified. The idea reconstruction when that is the case is to do an end to end reconstruction, an excision, end to end reconstruction. This is a post operative angiogram showing the reconstructed vessel. This is a 79 year old woman with a warning leak in this aneurysm, which you can see here, right MCA. This is a pre-op MRI/MRA, again showing the right MCA aneurysm. She did not have an STA because of a previous facelift. The aneurysm is partially thrombosed on this angiogram, and it has a complex morphology. This is a M1, this is a temporal M2, this is a frontal M2, which quickly bifurcates and not the interior temporal artery. The aneurysm is dysmorphic at its base, and you can predict that clipping might be either difficult or impossible. And indeed at surgery, I was not able to clip it. And what this case demonstrates is use of the anterior temporal artery into side, going to an vessel efferent to the aneurysm and the anterior temporal artery is an excellent donor for this sort of In-Situ bypass. And the aneurysm was trapped and recirculation preserved because of the interior temporal artery. Again, that's a view of the 3D angiogram showing the anastomosis M2 side of the interior temporal artery coming this way, this due to the aneurysm and the aneurysm trapped between clips. And that's the post-op MRI, she did have a small stroke that was clinically not significant, and she made a full recovery. An example of a posterior circulationm, there is a PICA partially thrombosed aneurysm in an elderly woman with TIAs. Again, the perfect use of an end-to-end anastomosis of the PICA, the PICA is particularly redundant, and the excision of the aneurysm resulted in this reconstruction of the PICA without needing to clip. And she did not turn a hair and did very well as well. So this is the simplest In-Situ reconstruction. This is an example of a subarachnoids hemorrhage from this PICA aneurysm. We can see the blood in the ventricles and the cerebellar medullary cistern. This double origin, probably dissecting PICA aneurysm, again, not amenable to endovascular treatment. Here it is again, and you can notice the double origin of the PICA. There is one origin coming from the level of C2, one origin coming from C1, and they meet together in a common trunk that leads to the aneurysm. Here is a view at surgery through a far lateral approach acute blood. Here is a first origin transdural of the PICA at the level of C2. Here is after the blood has been removed from the fourth ventricle, but not attacking the aneurysm yet. Here is the second origin at level of C1. This is C2, C1, the aneurysm is burdened in this clock. This is a distant PICA. Please note the perforators and how it would have been unwise to trap or endovascularly occlude the segment. It would have undoubtedly resulted in an infarct to the posterior cervical cord. And now we isolate the two origins meeting to the common trunk here to yield the aneurysm. And after exposing this aneurysm, it is clearly a dissection that's not clippable. Again, end-to-end anastomosis after excision is the ideal treatment. There is a completed end to end anastomosis. And that's a post operative angiogram showing a nice reconstruction and disappearance of the aneurysm. And again, a different view of the post-operative angiogram. How to avoid complications. I've learned through mistakes mostly over the years, that it's very important, of course, heparinize thoroughly with not intravenously, but irrigation with heparinized saline in the lumen of the anastomosis. Thorough cleaning of the fascia on vein grafts and radial arteries, because these, they can catch the suture, the running suture. Do not make the mistake of having the graft being too long, because once you establish flow, the graft will lengthen and can kink on itself. I do not like to excise ellipses of vessel wall on the recipient artery, I prefer the anastomosis to be as wide as possible. When doing an end to side I do not anchor the heel and the toe simultaneously. I anchor the heel generally first, and I keep the tool free as I will demonstrate in the video, that leaves me more room to run the suture. When you have a flap formation in a plaque, do not do an endarterectomy as this will lead continuous dissection of that plaque. You're better off trimming it and tack it up with the stitch. Getting out of trouble for occluded recipient, you of course reopen the anastomosis or you just make an opening, a slit in the donor, just above the anastomosis, through which you can explore both the donor and the recipient vessel. Fix the kinks, remove external compression. And if you have hyperperfusion problem interoperatively, you can certain use ultrasound, evacuate an intercerebral hematoma, and manage the blood pressure appropriately. And to finish my slide, PowerPoint presentation, and again, with a sense of levity, as I mentioned to my residents and fellows and trainees, that I've established what I would call the 10 commandments of bypass surgery. I will not read to you the biblical language of it, but just read the real English language of it. Commandment one, select your patient appropriately, make sure the bypass is necessary and that it is superior to other simpler methods. It's very important to do the simplest bypass possible, so-called expediency. It is important to be arrested physically and mentally because it is a demanding procedure that requires surgical proficiency. A common mistake is to focus on a tree and forget the forest during bypass surgery. It's very easy mistake to make, you have to acquire the experience and to be able to master both the forest and the tree at the same time, and that certainly comes with experience. Very important to clean the last segment of the donor graft, that is commandment five. Commandment six, use irrigation heparinized saline to combat any clot formation. Commandment seven, use flow quantitation interoperatively, I cannot stress how important that is. Commandment eight, do not stitch if possible, rather deal with the aneurysm at the same time. Commandment nine, very important to educate through training courses and commandment 10. I'm sorry, the slide does not show you to reformatting, do not hesitate to break any of the previous rules, if the opportunity arises, essentially be creative and be adaptable. So I'd like to start with the first video of a giant thrombosed left MCA aneurysm. I'll be using a left cranial orbital approach. I'll use radial artery graft going from the common carotid in the neck to the temporal M2. It's a 53 year old female with progressive headaches, and she had been watched by at another institution with this aneurysm back to 2008. And you can watch the natural history of this enlarging aneurysm. And this is now 2011, getting larger, more headaches, and now she comes to me. Notice the fenestration in the M1. Here is the angiogram domenico ectatic. So I decided, of course, this is a high-risk aneurysm to leave untreated. So there is a cranium orbital approach, you can see the periorbita there. After all I do a 2PC see a cranial orbital approach or osteotomy is here. We open the dura, We're gonna take a radial artery from the arm. Here is the radial artery. Very important, I cannot overstress how important it is to clean the distance inch of it. Now we've split the Sylvian fissure. You can see the mass of the unopened aneurysm here to our left. Here is now the distal M2. It's again, a temporal M2 aneurysm. So this is the vessel coming out of the aneurysm for just a few millimeters before it bifurcates. So instead of, of course, suturing to this very difficult segment, we're better off suturing to this three year segment. This is the end of the radial artery. I like to use ink to mark and size up the width of the donor to the width of the recipient artery optomix excuse me. We are put temporary clips on both ends of course. It is a deep anastomosis, you will notice the it's not on the surface. This is deep by the aneurysm. This is a 9-0 Epsilon suture, and here is my point about not anchoring both ends. So you go out in, out in, on the donor, in, out on the recipient, and please notice how using a curved needle holder makes it easier to make turns. So we tie this and we're going to run one side of the wall without anchoring to the other end. If I had anchored this end, I'll be to be very tight and very crowded. I won't be able to see both edges easily. So here I have the liberty of being able to push up the donor you see to one side so I can catch one wall and then catch the other wall. The vision is so much better when the two ends of the donor are not anchored simultaneously. Notice, I alternate sometimes between a needle holder or a forceps, the forceps is weaker, but it is a lower profile. And if the wall is not too thick, it is a quicker way to pass a needle. And also notice that my hand gets in the way, because it is a deep bypass and the thumbs the finger get in and out of view, we are a little bit tunnel visioned at that depth. And that is a similar experience to when you do a PCA bypass subtemporal as well. Kind of similar feel. I'm almost finished with half a wall. You notice the loops are left loose to be tightened after the entire suture has been passed, because if you tighten them as you go, undoubtedly, one or more loops will loosen and then you'll have a leak. So you want to tighten them at the last possible minute before you tie the suture to itself. And I do usually do two loops around the forceps so it doesn't loosen. And the difficulty of course, is to drive that thread that roll all the way down rather than pull up the complex. So we've done one half, now, we're inspecting inside the lumen heparinized saline, we take another suture, and we do a seminar running from that side as well. Again, it's easier, at least in my hands, it's easier to run a suture towards myself rather than away from myself. We doing the same thing. Now the view is a little less because we're anchored on the other end, but again, you have to do it to do it bite by bite, making sure we don't catch the back wall as we do that. Again, leaving the loops loose, And at that depth, it's not always possible to catch both walls in one bite. So it's perfectly fine to do it in two bites as I'm doing here. Particularly as you notice, when you have to pass the needle facing yourself, and here probably is the hardest stitch is to really curve it almost straight out of the field. When you don't have room for your hand to lean your hand backwards, as you have the luxury of being able to do in an STA-MCA bypass, for example. So here I'm tightening the loops one by one. And as you will notice later, I will tie it to itself. And when I release the clips, you will see there will be a small leak here, and it's a simple matter to add one or two interrupted stitches at the leak site. I will put a temporary clip here, so I don't have an entire column of blood. Rather I'd rather have heparinized saline in it. So I released the clip. I noticed the leak here. I re-close the clip, at least it got the air out. I'll put one interrupted suture. And again, as you will see, it will need a second one. At first, it seems fine, but in a second, there will be a small leak. And I thought, even though it might be okay and I could put surgicel, this is a rather large caliber bypass. I will add a second interrupted stitch. Here is the other stitch, and that will take care of that leak. Now, a step that's very important. Once we removed the temporary clips, I probably edited out of the video. It's important to measure flow in the recipient before we proceed to make sure there is no thrombus in the recipient and if there is a problem, this is a time to deal with it. So now I've done the radial artery preauricular subcutaneous into the neck where the common carotid is exposed. I like very much the common carotid rather than the external carotid. I only use the external carotid when the patient feels a balloon test occlusion. The common carotid is easier. It's more superficial. It avoids kinking, the problem of kinking, the graft against the angle of the mandible. It's a more natural curve. Yes, the graft will be a little bit longer, but I don't think that's significant. You can see me using an aortic punch, like the cardiac surgeons use for coronary bypass grafting. You can see a self suctioning device in the background. You can see, I lifted the common carotid towards me to make the anastomosis more superficial. And this is a seven or proline, exact same technique, of course, a lot easier larger vessels. And the more superficial you can go very fast with this. And this is an excellent anastomosis, of course, for trainees to, to get their bypass experience going here. If a mistake is made is very easy to revise that bypass. Same technique, tightening the loops one at a time. And then for the back wall, you will notice my assistant will need to lift and evert this radial artery this way so I can see the back wall. Again, so now my assistant is everting the graft and I run the back wall again with relative ease because I can see very well seven or proline. And again, please notice that the curved needle holder really makes it easier. I can manipulate the needle in whatever direction I wish it's much harder to do this if you're using a straight instrument. You can back suture with a curved needle holder. You cannot easily back suture with a straight needle holder. And again, we tighten the loops, same technique. Notice the diamond dusting on these instruments. They're very eight traumatic. And even though your first few bypasses, you will probably tear sutures, but with experience, you know how much you can get away with when you manipulate it. Releasing the bulldogs, and you can see the natural unimpeded course of the radial artery, get some anastomosis. I'm sorry. Get some hemostasis going back to the head, making sure everything working, and now we're ready to open the aneurysm. We're gonna temporarily trap it. And we're going to do the usual thing we do with the partially thrombosed aneurysms. We're going to enter it with a knife here is a temporary trapping just below the level of the anastomosis. This is avert common trunk I talked about earlier of the temporal MQ. So while I'm doing this now bypass flow is going. There is no real ischemia going on now. So here is the second all of the aneurysm, we're gonna open it with a 15 blade, the usual thrombus, we're gonna take a coosa, we're gonna empty it. Yes, we are rushed for time, but not that much because the bypass is Peyton and his circulating profusing the brain. But of course, there's no reason to be too slow in this step either. You will notice also that thrombus will take me to the ostium of the temporal M2 where it's heavily atherosclerotic. So also notice that the clip, this temporary clip I put in is actually occluding one of the branches. So that cannot be the final clip that the final clip needs to be proximal to that, to free up this bifurcation point. To do that it was necessary to do an endarterectomy as which is what I'm doing here. Notice the ostium of the stem portal. Now, I place the permanent clip below this one. Then we will release the first one. Now, the bypass flow that's coming down this way, goes into that branch. And the ICG shows it to be Peyton as well as a flow measurements. Here is a Peyton bypass to the ICG, taking it down into the neck. And the anastomosis looks good at the common carotid as. And the aneurysm now is trapped completely. And we will proceed with the closure. Here is a post op MRA. It looked like the graft is stenosed, but it is an artifact of MRA because on angiogram, it looked perfectly fine. I'm sorry, the aneurysm is occluded. You can see the trapping clip here, preserving the frontal end to and the lenticular strides and the patient did extremely well. No strokes. There is a source the MRI postdoc with no stroke and aneurysm is cured, and we can proceed to the next video.

- I wanted to ask you three questions. Number one, this was almost a distal M1 aneurysm, is that correct? And you distill it trapped. It is unique to put clip proximal to the aneurysm or not, or this was-

- Yes. No, it was, they did not show because of the subtraction. There are clips across the origin of M2. It's really a fusiform temporal M2 aneurysm. The M1 is short, but it's the lenticular strides were already-

- Taken.

- I had taken off in the proximal.

- So you did put proximal clips to the aneurysm on the temporal branch of M2.

- I did it probably wasn't clear in the video, they were edited out, but on the post-op angio, you can see them.

- Okay.

- So yes, the aneurysm is trapped. We only included, I guess, in the video, just the distal trapping clip from.

- Your second question is a general question. If you are occluding the internal carotid artery for a fusiform M1 aneurysm, it's only a Hunterian ligation so, occluding the carotid distal to the anterior cordial. Do you think an STA-MCA bypass is adequate, or do you need to high-flow bypass?

- See I, again, following the lead of Faddy Chevelle, who really was the first to explore this concept of measuring flow, really, we should not call them high flow, low flow, and STA I've measured STA flows of 140 CC per minute. So again, you tailor it to what you need. If you measure the flow in the STA, you measure the flow in the vessel you're planning to sacrifice while the temporary clip is on. The difference between baseline flow and flow with temporary clipping. If that difference can be provided by the STA, the STA is all you need. If it cannot be, then you take a higher caliber flow, a caliber graft, such as radial artery. I, you know, I cannot really answer the question in general terms, except that I am guided in every case by quantitative flow measurement to tell me what I need to do.

- And the last question is, if you have an option of bypassing to the temporal versus frontal branches, do you have a preference to which one would be the donor or the recipient vessel?

- I generally like the temporal, they're a bit more redundant, a bit more free in anatomy space. And generally generally have a slightly better collateral.

- Thank you. Let's go ahead to your PICA PICA bypass splits.

- So this is a left vertebral artery, PICA origin, large partially thrombosed aneurysm. You will see from the history in a second. And again, I think Samuel Hamadi who now is my partner who had helped me edit those videos. She's 66 and has three week history of gradual foot weakness. You can see the source images of the MRA. You can begin to see a by Loeb PICA aneurysm here, here is on the DSA. The problem here, the PICA arises from the base of the aneurysm. So maybe this part could be coiled endovascularly, but I don't believe that to be the best statement for this case. And look at this other low pointing totally different direction. Really not cannot be done satisfactorily by coiling, perhaps flow diversion, but really we don't have too much data in this location for flow divergence. So I elected a far lateral approach. You can see the position the way at least I like to do it. I still like to do a hockey stick incision. Some prefer a straight incision. The first few slides will be to remind, at least the people in the audience who are not too familiar with the far lateral approach, what the surgical steps are. At least I elevate the myocutaneous flap all essentially in one last, as opposed to creating that space between layers. Important to this notice the very large in this case, a very large Emissary, a conduit Emissary vein, which I will have to deal with here is C1. I'll be looking for V3 segment of the vertebral artery over here. I like to remove arch of C1, at least half of the arch of C1 with a foot plate of midas rex drill one cut here. A second cut here just beyond sulcus arteriosus is sulcus arteriosus protecting the V3 segment of the vertebral artery. And then if need be as often is the case you drill with diamond, that remaining stump arch of C1. Here is a tiered so-called teardrop craniotomy. If the forum and Magnum lip allows you to do it, you can certainly try a start. I'm sorry, your craniotomy with a foot plate here, or you can certainly add the Burr hole here to start it. It doesn't really matter. The to do proper far laterally to get to the condyle. We're gonna drill this with a diamond drill up to the condyle, but not into the condyle in this case. Those are the steps of the approach. The purpose is to have a dura opening that is very flat laterally. Now notice here the difficulty of this case, or the slight difficulty of this, really large calendula Emissary vein, that was in the way. I knew the patient had the paint and sigmoid sinus. So I knew I could sacrifice this, but be aware that occasionally the calendula Emissary vein is the only Venus channel. Notice the articular surface of the occipital condyle. This is what this three-quarter proposition gives you. It gives you an excellent view of the occipital condyle. If the patient had not had the neck placed in that position, it's very hard to see this. So I'm dealing with the calendula Emissary vein look at its canal, it's quite large, we keep drilling this bone. Now, we're into really the super calendula portion of the far lateral approach in this case. And I needed to get this bone out of the way. So I reached the equator of the forum and Magnum, which is what you want to do with any far lateral approach. Here is a V3 segment of the vertebral artery. Arch of C1 stump has been drilled thoroughly beyond the entrance into the Vista dura ring. I'm sorry, not the distributor ring, the vertebra ring. Now, we're ready to open the dura. This is a glimpse of what you're gonna see later in the video of spinal accessory nerve, the we're gonna have a glimpse of the aneurysm in a second. These are ninth and 10th nerve nerves, and this is an intradural V4 segment of the vertebral artery. It is a heavily atherosclerotic wall of the aneurysm. Here is a distal vertebral artery beyond the aneurysm. And this will prove to be non-clippable. And what may not be very obvious in this picture is the PICA origin arises just from here from the base of the aneurysm. I did try to clip it, but could not clip it. We, after these slides, the video itself will show in in a second. But again, to show you what will happen, this is the two loops of PICA, which I will end up bypassing side-by-side side-to-side PICA in the Tino venal tonsillar segments of the PICA beyond the perforators, the so-called source segment of the PICA. You can see what this exposure does for you, in the same view, we have the aneurysm up here and we have the two PICAs at the midline here. Again, steps of the approach, which I will elaborate on during the video, you have to do the back wall. Then you have to do the front wall and that's the anastomosis completed. Look at the aneurysm there. Now, we can proceed with trapping of the aneurysm. The set of cerebellar tonsil is lifted with self retaining retractor. And this is the three clips. Now, here is the actual live video. I'm trying to expose the distal vertebral, figuring out whether I can clip this and preserve the PICA. It has been edited out of the video, but I had a few attempts at placing the clip here and the clip kept slipping on the vertebral. At this point, I guess the video. Yeah, at this point, I made the decision to go to the bypass and improving the view here, just in case I could clip it so cannot be clipped. So we go to the bypass. Side-to-side bypass offers a different set of challenges compared to the end to site. First of all, obviously you have to do it in a running technique. You don't have the option of interrupted because the back wall is away from you. You cannot shoot your upside down the stitches. So you end up usually with four temporary clips into what will end up being as an H configuration, the letter H. I like to use a 27 gauge needle to puncture the artery and then use either a diamond knife or a beaver blade. You see that needle, the purpose of it is to start the hole. And then in that hole, you put your knife and you can certainly use scissors, but I prefer to use a diamond knife or a beaver knife as you see in this case. Again, I like to ink the wall because they get to be very thin and tough to see the edges. I noticed some backflow from a perforator. So I replaced my temporary clip on this side of the perforator. So you absolutely don't want any blood back flowing during your bypass. Here is the 10 oh V75-3 Ceylon suture. You have to start with the back wall out in on one side since I'm right-handed. I don't go out in, on the right side, on the right vessel in, out on the left vessel. You tie the knot and here is a key step. You have to pass the needle behind that knot to grab it from here. Otherwise you cannot turn the back wall. So you grabbed it from here. Now you go out in on the left vessel, again because I'm right-handed, you can reverse all this, if you're left-handed. Out in, on the left vessel, in, out on the right vessel. And then now you're on it from inside the lumen. So it's that step of passing the needle behind the stitch that gets the beginners a little bit in a quandary. What's going on there, but that's a key step. Again, of course, you have to have measured your two cuts I, again, like to leave the loops loose. And I, of course, don't anchor this end either for the same reasons I mentioned before. Now, the loops can be tightened one by one. You will see a repetition of a theme in this presentation with how at least I suture in a running technique. I tie it to itself. I make sure I have not stenosed the arteries in the process. You pass it in all the four directions. Now I'm satisfied, and this is a time by the way to fix any mistakes. Because once we do the front wall, we cannot see the back wall anymore. So frontal of course is easier. We're gonna run it in a similar way. Again, very important not to grab the back wall by mistake. And again, same technique, loose loops to be tightened hand over hand before the final dying of the suture. When I say hand over hand, I mean, one hand pulls the other hand gives counter traction against the tissues. Now, I tie it to itself. Now, I released the distal clips first. It's good to see some backflow. It's good to get the air out. I hate a bypass that has absolutely no leaks whatsoever. When the clips are removed, you should be worried that it could be thrombosed. Tiny little leak here in this axilla, very easily fixable by placing the surgicel, not necessarily on it, but as you see here, I'm pushing the two vessels against each other, and that stops the leak immediately. Now, the bypass is structured. I'm happy with expectancy. I proceed to place the trapping clips, distill vertebra, proximal vertebral, and PICA. So three permanent clips here. I just revise the approximate vertebra to place it a little closer. And I do an ICG, which I believe is not in this video, but shows excellent patency. Aneurysm is gone. There will be a post-operative angiogram, which will demonstrate the results. A little bit of surgicel. Here is a post-operative angiogram. One vertebral injected. Here is a bypass, anastomosis is here, It is a trapping clip. Here is the anastomosis. You can notice the so-called elephant foot design. What I mean is that the anastomosis site is actually wider than the caliber of each vessel. That's what you want. You not want any stenosis. And the aneurysm is clipped. You notice through the CT that the condyle has not been entered it's through far lateral. Here is condyle, barely the cortex of it here.

- Beautiful work Jacques, that really a spectacular job on a very, very difficult couple of cases. Let's go to the last fall, which is, I believe a giant PCA aneurysm is that correct?

- Yes, thanks Adam. So this is the last case, a fusiform giant PCA aneurysm. It's at the P2 P3 junction. I will be using a third technique that I would like to demonstrate is that of a short interposition graft. She is 63 years old was having progressive difficulties. You can see the partially thrombosed PCA aneurysm showing on this MRA. You know, it's partially thrombose of course, because the source images show some patency in the vessel. We will appreciate those in a second, much better. When we do the 3D reconstruction here is thrombus and here is the MRA reconstructed images. You have an idea what's going on, but really it's a DSA left vertebral injection that shows us ugly, looking like string of three beads. You can think of it. The old test was negative. There is no, I'm not negative. There is no good pecan, but please notice the P1 is healthy. P1 is healthy then P2 becomes aneurysmal follow the 3D rotation. P1 is healthy, then three different partially thrombosed globes in a fusiform manner. And here noticed very dolichoectasia. Very I'm sorry, I see a very unusual appearance. And so I thought endovascularly, I'm worried about sacrificing the PCA. So I elected to do a radial artery graft. I'm ready to go to the neck, but you will see that during the case, I changed my plan instead of bypassing to the neck, I will bypass from the PCA to the MCA because it happened to be there and there's no reason to go to the neck in this case. I do need a sizable bone flap to be able to go subtemporarily, to get to the PCA and through the Sylvian fissure to get my original plan is to get to the P1 and trap the aneurysm through the Sylvian fissure. But as you will see shortly, I cannot get to the P1 because of the mass of the aneurysm. It prevented me from getting approximately control of the PCA. And you will see very shortly, the actual PCA aneurysm, herniating into the Sylvian fissure with the thrombosed posterior communicating artery. I had never seen a pecan lifted up like this sitting in the Sylvian fissure. So clearly I have no access to the PCA through the Sylvian fissure. So my plan changes interop. Now I'm I'm subtemporal, but I had the bone flap land this way in case I needed to do this. So now, we're subtemporal I do have to sacrifice a couple of small bridging veins to get to the PCA in the P3 segments. So I am subtemporal. I can go pre temporal and I can go transville. So you notice we have three surfaces of the temporal lobe exposed. Subtemporal surface pre temporal, and Sylvian fissure surface. So here is now the distal healthy PCA. This is edge of tentorium. In these cases, you really cannot do these cases without the self retaining retractor. And I'm trying to identify a good segment. This is salamu genitals branches branches. So obviously where I need to bypass is this segment. This is the end of the aneurysm. You can see the atheroma, you can see the white atherosclerotic wall. So this is the only healthy segment available to bypass to. What I'm doing here to even give me more room is cut the tentorium I've already identified the fourth nerve. I like to cut the tentorium from its middle towards its its edge. It's better control this way. If we get into venous bleeding in the tentorium, it's very easy to coagulate or even inject tissue sealant. And I shouldn't get back. You can see the added room I have. So, now I want to pull this edge this way. Now, this is a trick I learned from is to use an aneurysm clip, to actually pull the free edge of the tentorium to itself. And that venous bleeding can easily be stopped with a little tissue sealant in it that stops the bleeding very easily. Now I have a lot more room to do the bypass at that depth. That is probably the hardest bypass to do among all bypasses subtemporal to PCA. Fairly close in difficulty would be ACA interhemispheric approach. So here is the radial artery. Again, cleaning very thoroughly its end, and putting an olive tip needle, fixing any side-branch leaks, either with a bipolar or with a clip or preferably a silk tie. If you use a tie, don't tie it too close to the trunk. I did fish mouth it a little bit so I can avoid stenosis if slight fish, mouth of the donor, and I'm putting ink on the recipient. Again, there isn't much room here except where the clips between the two clips. So you will see a repetition, a little bit of what I said in the first video. When you suture at depth, I like to bend a 27 gauge needle, make your first puncture site, use your either diamond knife or beaver blade because it's the radial artery. I'm gonna use a nine hole and I'm going to use agains three eighth of a circle rather than half a circle. By now, those of you who've been watching this whole webinar will be used to what I'm going to say next. You're gonna do out in, on one vessel in, out on the other vessel, anchor it don't anchor the other end run one half of the wall. Again, the importance of a curve needle holder to make these tight deep turns.

- We'll go to the next video momentarily.

- That is the running of one half of the wall. Leaving the loops loose. Again with experience, you kind of learn the sweet spot. What I mean with those three loops, you're leaving. If you leave them too loose, they get in the way. If you leave them too tight, you cannot grab them at the end. So about where I'm doing it right now, I guess, is what I feel is the best compromise between not too loose, not too tight. And again, notice I'm passing the needle almost backwards. You cannot do that with a straight needle holder. You need that curve to go backwards on yourself, to do the final end of the suture. Now, we tighten one by one, one hand pulls the other hand generally pushes down on the vessel wall, traction, counter traction, and I tie it to itself and I flipped the graft and I'll do the other side. Before I do that, I'm inspecting inside to make sure the lumen is healthy and there is no flap formation. And we're on this side.

- Can you comment again why did you not go to the neck and use the MCA in this case? Would you explain that again, please?

- Yes, I was planning as you know, to go to the neck. I had not opened the neck. I prepped it. Actually, it will become clear in a second here. I'm going to, remember I split the Sylvian fissure and I noticed there were redundant, healthy M3 branches. So why create a new incision and tunnel it and have a longer graft. I have a donor setting in the Sylvian fissure. So, and as you will see in a second, it's an M3 branch, which tolerates eminently, temporary occlusion. As you know, we need to keep grafts short as possible. So here is the M3, very easy to suture this to this, instead of going to the neck, the only reason I had split the fissure, as you recall, is to get to the aneurysm. I had not split the fissure to do this, but I noticed it's there might as well use it. So I could go to the actual M2, but why put the entire empty territory at risk of temporary ischemia? I might dwell go to M3. It's plenty big to match the radial arteries. That's what I'm doing as you can see, of course the flow is still going down this M2, it's only this M3 that is under temporary ischemia, which is not a big deal at all. Same technique, after doing that deep anastomosis, this anastomosis of course is much easier and we'll go faster, but exact same technique. I don't know Adam if you have any questions. This is probably a good time because it's set a petition. So when I can-

- So you're essentially going, the graft is going on the lateral temporal lobe and just goes into the Sylvian fissure. And although you're absolutely right, there is a big advantage of a shorter graft, which is nice to have, I guess we have to always remember that this puts two intercranial vessels that risk better than one. Although M3 is relatively a much distal vessel and it sacrifice as much as consequences. But again, if you don't have a very good M3 and it's small and it's not easily accessible, probably it's not best to place one of the M2 branches at risk with this pipelines, do you agree?

- Yeah, you know, M2 also you get away with, I mean, that's where we do all as you know, all long graft bypasses. I really do not recall a single instance of a complication due to the temporary occlusion portion of the surgery of an M2. So I probably still would have gone to M2, but certainly again, I agree with the principle of what you're saying. Let's put it this way, if you're a beginner at bypass that is not the first bypass you want to do, you certainly go to the neck, do the safest thing you can possibly do. But you know, after several cases you acquire a certain confidence. You, can do it. I'm removing now the temporary clips, it's a good anastomosis. We did do an ICG, which I I believe is edited out of this video, but you will see the... By the way, you can see the graph going around the temporal lobe around temporal lobe, into the Sylvian fissure removing all the clips. The next point to make is what to do with the aneurysm. I could have placed a distal clip on the P2, P3 just before the anastomosis, but I did not. That probably would have cured the aneurysm. I've had one bad experience of doing that. The so-called distal occlusion. So I elected in this case to coil the aneurysm on post-op day one, to have complete obliteration of the aneurysm reserving P1 and here is a bypass going from the M3 to around the temporal lobe, to the P3. And the aneurysm is now of course, completely occluded since it was coiled coil occlusion of the PCA. And that really finishes my presentation.

- Well, Jacques masterful work. Really, this is masterful surgeries by really people who have extreme experience with vascular neuro surgery requires a lot of, you know, a maturation of technique rather than just starting for a beginner neurovascular surgeon. And I wanna really thank you for your time this evening, and thanks our viewer for being with us.

- Thank you, Adam, for the invitation you. Thank you so much.

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