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Complication Avoidance in Cranial Surgery: AANS 2016 Tues Operative Session

William Couldwell, Michael Lawton, Robert Spetzler and Paul Gardner

June 12, 2016


- [Aaron] This session today, our speakers recorded no introduction, Dr. Robert Spetzler, Michael Lawton, Dr. William Caldwell, Dr. Gardner will have a great set of videos that I think you'll all find very instructive and interesting. So with that, I'd like to ask Dr. Spetzler to start his video series. Thank you.

- [Robert] I do wanna acknowledge my collaborators, Kalani, who's a chief resident, and Kaan Yagmurlu, who is a fellow who's doing a lot of anatomic resections. So the people that are not on there are, unfortunately, for example, Michael Hickman, who has done this computer animation, and the whole group of artists under Mark, direction. We can go onto the first slide. So what I have done this year as opposed to previous years is just literally talk about one topic, and that's cavernous malformations. And here you see cavernous malformation really right at the end of the aqueduct sitting right in the aqueduct in the posterior third ventricle. I think you can't overemphasize the importance here, you're retracting between, and that was the fornix. And I wanna point out, I don't know whether Michael Lawton will show, but here is the fornix here. And what we've done is we have gone lateral to the choroid plexus, and that puts the choroid plexus against the fornix, giving you one more protective layer to the fornix. Now, here, we're in the third ventricle, we have our lighted sucker, we're down deep, and we are right into the entrance of the aqueduct and we see the cavernous malformation. Now, with edited videos, what you're really missing is all the extra dissection that's time-consuming, and you'll always see the sucker being used as a counter pressure. I use this sucker really not only for section, not only to deliver light, but it really becomes a very important tool as a dissector. It's what I sweep around to get, and here are the cavernous malformation comes out, and here we see the postoperative exam, the MRI scan right where it was. This one is for an optic chiasm lesion. You can see it here, patient this old, but he's losing the last bit of his vision. We're going through an orbit of psychosomatic approach to get right to the chiasm. And here we're coming down, frontal lobe, temporal lobe. And one of the chief residents is opening the fisher here toward the bottom. And then we get down to the lesion. You could see the whole chiasm right here. You could see the cavernous malformation and the many mulberry lesions, and you'll always see these little veins getting to the cavernous malformation, which I think is really the pathology. It's sort of a budding process of the veins. So here we have hemosiderin everywhere. Hemosiderin is very toxic to the brain, and it's really that hemosiderin deposition that cavernous malformations do all the time that's so problematic. The end toward the third ventricle, and then always counter pressure as we take it off, going across the chiasm, the right optic nerve, the right optic track, right underneath. Tiny little pituitary-like instruments, and then just going back and forth cutting out the lesion itself. And when you have lesions like this here, you really are caught with the problem of do you have it all when they're diffused like this? And you'll see me toward the end spend a lot of time pulling out the tiny little white fibers that are all along here, which I'm sure are still all part cav mal, to get the rest out here. You see part of the cavernous malformation hanging down. And here you see the back end of the cavernous malformation, just using the scissors also to push away the normal brain or semi-normal brain, and there is the lesion, internal carotid artery optic nerve. And then really spending time to get rid of anything that looks like cav mal. These are little micro forceps that have teeth on them. They were kindly made by cogent for me. And so with the sucker as counter pressure, I'll go around and pick up everything that looks like a cavernous malformation residual. And here you see where the cav mal was resected. This is for a contralateral interhemispheric approach for an interventricular cavernous malformation. So here you see one up on the top. So what's the best way to get there really? The least amount of brain retraction. While you can do the whole thing by having the head horizontal, you are coming in from the left hemisphere, which is being retracted by gravity, and then we're going to go through the faux through the singular gyrus, right to the lesion. And that approach is a very, very safe approach. Singular gyrus is very tolerant for an incision. It is the shortest distance, but you can see coming from across the other side, and now we're in the ventricle. And if we did it right, we should be seeing the cavernous malformation right by the ventricle, and there it is, sitting right in the wall of the ventricle. In my mind, the ventricular cavernous malformations that sit in part within the CSF space have a greater risk because when they bleed, they're not being tamponaded by the surrounding brain. I had one cardiac surgeon from Oregon who had two hemorrhages, which were almost fatal because he cast it as ventricular system before we removed the cav mal. But you can see just a classic cavernous malformation, lighted instruments here helped so much in order to see these bipolar has a light source in it, which is shining right down at the region, and then you can, you see that utilizing the sucker as your retraction against the instrument that's holding the cavernous malformation, until we finally get all. No retractors in place, all gravity. And here, you can see the route right to where the lesion was. For the pontine cavernous malformation, this is a suboccipital approach. This is a very unfortunate a 24-year-old, because you could see the entire brainstem is full of telangiectasia plus the cavernous malformation. This is the approach. Just remember that the foramen of Luschka can really be opened up virtually completely, and that allows you from lateral to medial, this whole exposure. Just remembering your anatomy is a key in order to avoid the critical structures, identifying the facial colliculus where the MLFs are. Patient is prone, and here you see this classic picture of raspberries everywhere. Everywhere you look, she has this. And in addition, she has a cavernous malformation. Now we're lateral. We're in foramen of Luschka. With image guidance, we have decided that this is the entry point, and you can see right where we're going, right to the lesion. You can see it right there. You also remember that she had a very large venous malformation in addition to everything else. And now we find the cavernous malformation. This is the one that has bled several times symptomatic, but I don't think there's any way that we can predict her particular prognosis when the whole brainstem is full of telangiectasia. And I think telangiectasia in many ways, it's the precursor of the cavernous malformation. Now, because we're out laterally, we're really mostly in a medial longitudinal fasciculus, MLF. This is a robust entry zone. If we were over here, we'd obviously be hurting seven, threatening Six and MLF, but here you see the cavernous malformation coming out nicely. But again, look at the floor, the fourth ventricle, all these little raspberry lesions everywhere, and then removing the gel foam that I always like to place on the distal fourth ventricle to protect the aqueduct from any bloody discharge. Here you see the empty cavity where we were and the preservation of the large vein. This is a lateral supracerebellar infratentorial approach for this lesion. I love these, all these approaches along the tentorium, because you can go all the way laterally all around and naturally, then if you need to go to the retro sigmoid, you have this incredible access to the midbrain, things above superior Colliculus fourth nerve, third nerve, spinal cortical track, and this is all we need, this little incision, lateral, retracting the sinus, looking down into the ambient cistern. You see the fourth cranial nerve. You'll see superior cerebellar artery vessels. You can go and expose the posterior cerebral arteries, and you can see with image guidance going right down to the lesion. That is really the key. And then despite the fact that this is a number of millimeters below the floor of the midbrain, you can get down there, and you can use the light at sucker here, which really exposes this very, very narrow corridor adequately so you could do your job. Fourth nerve up above SEA, the sectors, no retractors in place. This is all just using the natural corridors, no drainage of CSF except what we've achieved when we opened the ambient cistern. And then you can see the various ages of the cavernous malformation as we're mobilizing it. And I think as we mobilize it, we take out pieces so that it fits through that small opening. And there it goes. And then again, even though I've said many times never bipolar in the brainstem, I do it all the time now. And then obviously we have to be sure it's clean. Here's the track. This is how we got in. Patient tolerates that remarkably well. This is for a pontomesencephalic lesion. As you see, a large one here. You can talk about a number of different approaches, but in this case, we chose the OSI approach. You could see the anatomy, and again, it's important, know where your third nerve fibers are, where your spinal cortical tracks are, mammillary bodies, et cetera. So here, we're opening, this is the optic nerve. Here we're going lateral to the third nerve. Now, we're lateral to the third nerve. You can see it's on a very high magnification. All that jerking you seeing is because I have the mouthpiece in between my teeth, and I'm moving it constantly. So I want to come in a little bit lateral to the cortical spinal tracks. That's why I'm lateral to the third nerve. And then I opened in line with the cortical spinal track rather than across, and then identify the cavernous malformation. And then with my foot braced against the operating room table, I grab a hold of it and pull as hard as I can. I guess that's why I've never been successful as a comic. Yeah. Tell him about you're the only one that I have to disclose that you happen to be my wife, and I pay her to do that. It's a large cavernous malformation, so we take it out piecemeal. You could see the different ages of the cavernous malformation from the different timings of hemorrhages, and then this of rotating movement to bring it out through an opening, which is significantly smaller than the diameter of the lesion itself. But you're really down very deep. You've got your carotid artery to the side, the third nerve to the side, you're in the ponds from an anterior trajectory. And this is where we went. And in this case, the patient had no change in the exam. So this is a pretty straight forward, anterior. You see the lesion here. We don't have to go across contralateral for everything. If you go straight down and that's the best projection to the cavernous malformation, then that's what we do. Beautiful anatomy. And again, here's the choroid plexus. I like to put the choroid plexus toward the fornix to give it extra protection. This is really not the opening I would have chosen. I would have made one little burr hole and going all the way a crowd. What is important is that you go across the sinus, that you tack the dura next to the sinus to the bone so you can put traction on it, and that actually allows you to bold the sinus just a little bit. Here's some cotton put above and below just to keep the hemisphere away while the CSF is straining. And then you can come really right straight down to the cavernous malformation, staying away from the fornix. And once you have that, naturally, the removal of this lesion becomes relatively easy. Again, you notice the light at sucker, that's made by cogent, looking at the vessels that have as the anterior spinal artery complex that we were looking at. And then now we're going out lateral, and you can see the diffused onus of the cavernous malformation. If you were just looking straight down, you would've thought we were done already, but you clearly see cavernous malformation over here, and utilizing the sucker, we really can inspect the area very closely and then just grab one little bit after another until we're very, very comfortable that we have removed everything that is cavernous malformation and could lead to recurrence. I think we're much better at preventing recurrence now, not still complete, but, and then anything that looks suspicious, we use the bipolar. Again, you saw the light and the bipolar. And that's really the exposure, and the closure. And as you would expect, there really would be no post-operative deficit. Thank you very much for your attention.

- [Aaron] Thank you, Dr. Spetzler. So Dr. Caldwell is gonna be a little bit late. He's in another session, so I'm gonna fill in for him until he gets here. Let's go ahead, and since we had such amazing cases for cav mals, let's talk about insular gliomas, 26-year-old right-handed male biopsy proven very large left insular frontal. So go ahead, please. You can see the functional MRI shows the function over the area. This is the large flap they had just for an open biopsy in the outside institution. We teed it off. The opening obviously involves opening the Sylvian fissure widely. You can see the tumor is coming through the transsylvian approach, the veins over it. We'll go ahead and just remove the tumor as much as we can through the transsylvian approach, the MC branches are identified early, as you can see right here, and then we'll work between these windows, between the MCA branches to remove as much of the tumor as we can. Unfortunately, the transsylvian approach will be limited and therefore we have to find a transcortical route. That's what we use mapping, in this case for motor speech. You can see the mapping and process. So language expression. As we find the most anterior part of the language, we'll go ahead and make a, therefore entering the posterior aspect of the full loop, leaving the veins over the Sylvian fissure intact. Use subcortical mapping along the posterior aspect of our resection cavity, so the motor fibers are not affected. Again, the patient is awake, which gives us another important feedback. Here is the small than two, arteries that should be protected at all costs. And then obviously neuro-navigation is used to remove most of the tumor until the normal white matter is encountered. The part over the cottage was left intact by more than 80% resection, which is accomplished. Mapping, especially important. But yeah, ligation of partially thrombosed anterior communicating artery aneurysms to the patient that progressive vision loss, partially thrombosed a, aneurysm, you can see the angiogram right side of temporal craniotomy. You can see the chiasm is significantly affected by the aneurysm fissure is exposed. The aneurysm is embedded in the chiasm. We'll go ahead and expose the A1 on the right. You can see the aneurysm again, embedded into the chasm, find a one Contra laterally and then clip strategy. One goes behind protecting high thalamic perforators here. Obviously there's will be a residual, in front of the A2. Temporary clip was used just so I can play around a little bit more and mobilize the neck and then I'll place it. I look across, can see that initially there's still some filling, both an ICG and flouricine and other straight clip is placed in a tandem fashion, open the aneurysm to compress the chasm, take the clot out. In this case, I didn't try to dissect the aneurysm wall because it was very embedded in the chiasm. I would have left to more injury to the chiasm. So this is just a quick case, nothing special about it. 62-year-old female with progressive visual loss, a very large chondrosarcoma off the anterior skull base, something that records both the top from the top and from the bottom approach. The, incision was used in this case. This cath lab is reflected anteriorly. In this case, we also elevate the prey cranium for the area of the closure. You can advance that a little bit faster for me, please, thank you. Here's a, craniotomy that was completed. The frontal sinuses were criminalized after which an extradural approach is completed to reach the tumor. Obviously doing this unilaterally will be problematic to reach the part of the tumor. Go ahead, please. You can see the old factory graph tract is disconnected. The tumor was removed from the top, then the closure was completed using the pre-cranial graft. And then we came from the bottom, and this time using the endoscopic approach, drilled away as much as we can, removed the tumor that around the area of the carotid artery and the ultimately the cranial closure is completed using that Prairie cranial graft, again, reflected anteriorly, the vascularized part, that piece of bone is placed to reconstruct this big defect just above the level of the pre cranium separating from the nasal cavity. There is the closure is performed standard fashion, and here's the final result. Relatively good resection of this, sarcoma. Anterior choroidal artery aneurysm, how can we clip these? Some of them originated from the neck of the aneurysm. 32-year female with thunderclap headache and xanthrochromia some stance on lumbar puncture. Here's the location of the aneurysm. Most often, the aneurism is originating from the neck. Here's the standard pterional craniotomy. Sylvan fissure is dissected widely. The rack with bands along this sphenoidal segment are disconnected. One of the bridging veins had to be quite just very immediately specially so one can see all the way across and elevate an untethered the frontal lobe, the internal quarter artery optic nerve, again, standard techniques for using a retractorless method for exposing the carotid artery, the origin of the aneurysm. Again, follow the wall of the, artery until the aneurysm is exposed. Here's the aneurysm itself, very easy to identify through this approach. Vascular control, proximately secure. Temporary clip may be placed if necessary. I'm usually generous in the use of the temporary clip. You can see the aneurysm completely across. he key here is to avoid grabbing the anterior core artery as it wraps around the most medial part of the neck. So one has to find the route of that artery. Obviously the origin of the neck and the anterior, artery has to be protected being at a clip, all this good in this area so you can see around the clip so that the artery is not compromised ICG often very helpful. You can see the artery beyond the tip of the clip lights, really easy operation, takes less than an hour to do and preserve the origin with a durable result in terms of excluding the aneurysm SAC. You can go ahead into the next one, please, for the sake of time. This is an interesting approach, posterior Peri-Hippocampus tumor, 62-year-old female with a seizure, single brain metastasis. I think going sup-temporal require excessive retraction, so we go across from the supracerebellar transtentorial approach and use a very small paramedian incision. I use lumbar drain in this case. You can see the turn of the head, the surgery is the highest point, two sutures around the tentorium, following the tentorium, cutting the tentorium in a T fashion, again, using the working angles as an important parameter of exposing the lesion rather than the operative space. So in this case, we're maximizing the angles even though the depth of dissection is going to be dramatically significant. So I put two sutures on the tentorial flaps. We'll go ahead and expose the posterior parahippocampal cortex. You can see these two sutures area of the tumor, and you can extend the anterior incision further. I use floor scene using the five 60 clearly identifies the boundaries of the tumor. No supratentorial retraction tumor is removed standard fashion. Very easy until quick plexus of the temporal horn is encountered. Obviously the PCA's branches are preserved here. You can see residual tumor that fluorescein fluorescence allows you to appreciate and therefore make sure you're all the way across that. Here's a branch through the temporal horn. You see looking all the way through the temporal horn and here's the work in corridor, again, avoiding significant mobilization of the dominant temporal lobe and here is the final result.

- [Michael] Thank you, and beautiful cases. So what I'd like to do is focus on some aneurysm techniques and discuss or show you some case examples, go ahead. First technique I wanna talk about was this cross-wise counterclipping, and a nice example of that is this vertebral artery aneurysm. You can see some mass effect on the Modela. In fact, her presentation was not subarachnoid hemorrhage, it was, I think, more of a mass effect. So here, what we've got as a far lateral exposure with the midline here, the condyle is up in the corner here and the cerebellum is down here. So our working window is in this triangle, this vagoaccessory triangle here, and the first step's always are to get proximal control of the vertebra, which is up here. The dentate ligament always overlays the vertebral artery, and so when you transect that, you really gain a nice exposure. You can see the rootlets of 12 running to their foramen, and here you can see 11 running up to juggler up in this direction. And this really forms this working maze to get through to the aneurysm. So there isn't a lot of space through the nerves, and so what we're gonna do is we're going to create a very small working window. This is just to have the PICA, the caudal loops of PICA in view, just in case the clipping doesn't go well, and we need to do a bypass, but our working window is gonna be right in here. And you can see now the medial wall of the aneurysm here, lateral wall of the aneurysm here, and then the vagoaccessory triangle in here that we work through. I use a temporary clip just to soften the aneurysm, that makes things a little bit more lax. And this is gonna be my little access window here, working away from the nerves, and the way that this counter-clipping technique works is that the heels go in at the same spot and the toes go away from each other. So you can see this is a 45-degree-angled finished rated clip with the toes aiming approximately underneath the dural ring here. And this is gonna take care of half of the neck, the proximal half. And having dissected this week and just worked the healing around the parent vessel and close half of the neck. So in order to get the other half of the neck, we're gonna have to put a second fenestrated clip. If you put the clip in the same direction, you've got to have extra room up in this direction. It's easier to cross the clips. So now we're going in essentially at the same spot, turning the clip 180 degrees and sending the toes distally pointing. So we're basically heel-to-heel on this middle portion, the heels overlap and the two overlapping blades then form this kind of angulated clip reconstruction. So the working window that we needed for applying those clips is quite small, we don't have to manipulate the nerves much, and you can see how the aneurysm blanches here. Confirms that we've got good flow in PICA, good flow in the vertebral artery, good flow in the megillah perforators and no filling of the aneurysm. This is YELLOW 560, so, has been injected, and I think it's a really nice way to bring out these perforators and make sure that those perforators apply to the brainstem is fine. And then since her presentation was one of mass effect, important to puncture the aneurysm and decompress. So this is that cross-wise counter clipping technique. It's a variation of the fenestrated clip application, but it's a real nice way to work through a very tight window of the cranial nerves. Here you can see. All right, this next case is also a PICA aneurysm. We'll stay down in that region, and you can see subarachnoid hemorrhage. You can see the lesion is right here. And if you look very carefully, it's a very small abnormality right at the origin of PICA. It wasn't clear to me initially what this would turn out to be, but you'll see here in a moment that this turns out to be a distal PICA fusiform aneurysm. So again, the vertebral perforates the dura here at the dural ring, the, over lies that, and as you cut the, and free up that gutter along the, you get a good view now of the anatomy. So the vertebral arteries here, the PICA is coming here and you have to just carefully separate the nerves from PICA so that you have the aneurysm in view. Now, this here is the proximal inflow. This is all aneurysm here, and this is outflow here. And what you'll see as I transect the aneurysm, oh, I wanna bring this to your attention. A small megillah perforator that's right at the very origin of the aneurysmal tissue. So I gotta preserve that. So this, I've taken this as close to that perforator as I can, and what I wanna bring to your attention on this side is that the dissected tissue actually extends further distally than I expect, so I have to keep walking back more distally and more distally again until I get rid of all of the abnormal tissue. It makes no good, make no sense and does no good to sew together disease tissue into your anastomosis. So you have to keep cutting back to completely remove that gap of disease tissue. And what that means is that the tension is greater on the ends because the gap is now larger. And so what that does, it creates a problem for me. It means that I can no longer rotate these ends of the artery. And so what you're seeing here is an insight to technique. I'm suturing this posterior wall of the anastomosis end-to-end, but I'm doing it intraluminally. So I'm inside the lumen of the artery here, and I have to pick up those two inner layers to sew it with an insight to technique. And when you do the insight to technique with such a small artery, like a PICA, it's helpful to leave the second anchoring suture off. So I'm gonna run this line from a single node here, and this is, because I needed a little extra tension or force on the suture. And I run that line all the way. That was just a 10-0. I don't need a 10-0 now anymore. I don't need a 9-0 rather for the second suture line because I've already approximated the vessels, but this is now a second stitch. It's my second anchoring stitch. And I'm gonna close off the opposite and the 180 degree end of the anastomosis, to complete that. And once that's together, then I can go back and I can take the slack out of that 9-0 suture. So I'm back inside the lumen, and I'm just working a loop by loop through the slack to bring that posterior wall together, and then I can tie it to the knot that I've placed on the opposite end. Now, this wall is much easier. You'll see now I've transitioned to an extraluminal technique. So there's been no rotation of the artery. I haven't moved the vessels at all. I've only changed the relative position of my needle from intraluminal now to extraluminal. And that's the answer to when you've got very little slack in the arteries and you don't have that ability, or you've lost that ability to rotate the ends. It's an important point because I think there's a hesitation to take out too much tissue in and remove the slack, but you've gotta get to the end of the pathology if you're gonna have any hope of having a, bypass. So here I've run the line. I've got my loops of suture. I'm just taking the slack out now, and you can see now here's the proximal and here's that perforator. Here's that distal end. And we've now completed the anastomosis. So the clips come off, there's a little leakage, easily handled with a little bit of a fibrillar, and some pressure. And there's that little preserved perforator. So this is that extra gap that I wasn't expecting, but that was also diseased. We've got patency here confirmed on the IC green and we've got a nice reconstruction. There's the vert. There's the PICA course now, and there's a vagoaccessory triangle once again. Post-operative angiogram showed a nice, PICA reconstruction here. All right, I'm gonna show you another subarachnoid hemorrhage case, this time being a basilar bifurcation aneurysm. You can see here from the angiogram, this is posterior projecting. These are some of the harder ones. And I chose this case for several reasons. One is I think many are not seeing vascular bifurcation cases, but I also want to show you the tricks that are necessary to get exposure, and that's one of them. Sometimes you'll find this temporal polar artery, one of the first branches beyond the Anterior coronal that can really lock in your temporal lobe. And so that's an expendable artery that you often will need to take, and if you're too hesitant in taking it, you won't be able to mobilize the temporal lobe the way that you need to. So here's the third nerve. This is the internal carotid PICALM coronal here. And the dissection goes along the third nerve through the membrane of Lula quest back to where the aneurysm is. So here's the second step I'm taking. Sometimes posterior communicating artery gets in your way. You can see we've got a very small working window, and by dividing PICALM, we can move these two ends of PICALM upwards and out of the way. This dramatically enlarged as your working window here. And PICALM is expendable as long as you've made sure that that's not a fetal PICALM, or fetal PCA. Now, here's the third trick, the post-decline node. Post-decline node is also an occupant of that carotid ocular motor triangle. And if you find that the bone is obscuring your view, you sometimes need to drill it down. So I've injected this ocular motor triangle here where the third nerve runs into its dural sleeve. I've injected that with TISSEEL. It forms a very nice cast, so you can control the venous bleeding, and now with the diamond drill, but we can take down the bone of the post recliner and further open the window. So we're basically one step shy of a trans cavernous approach, but this is all that we need. We don't need to take it to that next level of going into the cavernous science. We just do these maneuvers and that brings the aneurysm into view. Here's the, here's the P1 ipsilateral and here's the aneurysm projecting up and we've got to find its posterior projection back here. So I'm clearing a site here for proximal control. I'm gonna use a couple of minutes of temporary occlusion time just to soften the aneurysm. There's the SCA. So we're just proximal to the SCA, and here's the fenestrated eclipse. So for a posteriorly projecting of bifurcation aneurysm, this is the standard clip. It allows you to rotate this blade here posteriorly back down the entire neck, and also keep the front blade along where it needs to be up high. There's a little dog here at the heels of the fenestration, and that's closed with this small closing clip. Note that that window I'm using every bit of that window, and those little tricks that I made are what opened it up for me. So here's the view. We got icy green. It's gonna confirm that we've got patency here of the P one segment all the way through the fenestration. We've got the contralateral PCA on the opposite side, SCA here, all looks good. And now I'm gonna show you the YELLOW 560, because I think the yellow YELLOW 560 is a nice way to check the perforators. There's very brilliant shine through with with the yellow, and it's a great way to check the patency of these perforators. So one of the nice things is you're not looking away at some monitor. You're looking directly in the field, and here I need to make sure that I preserved every perforator. Here's one here, the critical one on the contralateral side. Here are the ones on the ipsilateral side on the high side of the P1. And here's some on the low side of the P1. So this is our check to make sure that each and every one of those perforators is taken care of. And so, again, the three tricks were the temporal polar artery, the division of the PICALM and the take down of the poster. Right, so here is a complex middle cerebral aneurysm. You can see that the origin of the temporal division comes really from underneath the underbelly of this aneurysm. The frontal division comes off over the top, so they're widely separated by this, morphology. And in this case, my strategy was that I didn't think I could clip reconstruct that. So what I'm doing here first is I'm putting a STA-MCA bypass, nothing fancy, but I'm taking care of that frontal division because I know that in order to reconstruct that bifurcation is gonna be very difficult. And if I can simplify my job by revascularizing the frontal division first, and all I need to do is to create a connection from the N1 to the N2 on the temporal side. So this is just an upfront step. You get it done, get it out of your way and you don't have to think about that other division for the rest of the case. Standard and decide technique. Here. You'll notice the artery flops nicely. You don't have to worry about insight to technique for this kind of a bypass. So that's our completed bypass, and that takes care of the frontal side of things. And now he can transition to the other trunk here. This is the M1 segment. This is that temporal division here, and aneurysm is all the way off the screen over in this area. So my first clip is gonna be a fenestrated clip because I'm thinking a tandem clip reconstruction is the way to go here. So I've softened the aneurysm. I've got this fenestrated clip on and you'll see, this is nowhere near where it needs to be. But so I apply a second fenestrated clip and then a straight closer to close the fenestration. This first clip, fenestration clip number one here is really only meant to be a scaffold for the second fenestrated clip. Okay? So that's our tandem reconstruction, but you'll see, as we go and check out our reconstruction here, there's compromise here of this outflow of the temporal division. So now this has fenestrated clip number two, I'm going on now with fenestrated clip number three, and now I'm gonna close off the fenestration, and this now becomes a scaffold. I can remove that. It's now a tentative clip. It comes out. But once again, fenestrated clip number three is even still too low. So here now, fenestrated clip number four, this becomes a tentative scaffold, and finally, we close off the fenestration here with a straight clip. So what we've done here is we've progressively walked the fenestrated clip further up the neck of the aneurysm to where it's finally in good position. And there's a little fullness here, which I can easily address within the fenestration with this curved clip. But now what we've done is we've rebuilt a very acute angle here between the M1 coming in and this temporal division coming out. And you can see there's nice fullness here that comes around that corner and make sure that that patency is wide open. Our ICG shows that there's a good flow, no delays. And when we puncture the aneurysm, it's completely quiet. So I refer to this as sort of a tentative stacking technique where you're tentatively walking a fenestrated clip further and further back with the help of this bypass so that you take the temporal trunk out of play, essentially, for the reconstruction. Here's the post-operative angiogram. Look at that reconstruction right there, it's very complex. And to have had the other division to worry about would have been tough. Another MCA aneurysm, this time a giant aneurysm. Here's the aneurysm. Here you can see angiographically, it's very much like that other one with an inflow artery, two widely separated outflow arteries. This case is a little different. I did not think that I could clip reconstruct even one of those branches because of their wide separation. So this, I'm doing an upfront double bypass. So this here, because he was a naturopath, the radial artery was unavailable, and I'm gonna use the A1 segment as a donor. The reason is that I'm a real believer in an intracranial-to-intracranial bypass technique, and to really push that philosophy, you can use the Circle of Willis rather than a second incision in the neck. Here is the A1, two little branches that I have to control first. But the idea here is that by using the A1 as a donor, you can spare the patient an additional incision. The graft is much shorter, and the A1 is a very tolerant donor site because with the AECOM, you can temporarily occlude that A1 segment for as long as you need to get anastomosis done. Now, you'll see, this is a very difficult anastomosis, is this wall of tissue here is giant aneurysm. So I'm up against the aneurysm here. It's a smallest craniotomy. So I'm up against a little blade of the retractor here. So it's not a lot of working space, very deep. And admittedly, it's a challenge to do this anastomosis, but you can do it. You can flop the artery nicely if you do this anastomosis first. This is the back wall here. This is our radial artery graph. So this is a end-to-side anastomosis with the A1 running continuous technique. And by doing this anastomosis first, what we're doing is we're arterializing the graft. The graft then becomes ready to re receive or supply each of the trunks from the aneurysm as we revascularize. So that's our completed anastomosis. Now we run up the Sylvian fissure. This is that frontal division. This is all aneurysm again over here. And we're gonna do this anastomosis side to side. So here's the frontal division. I've made an arteriotomy here in the vein graft. And this now will be an insight two technique. So like what I showed it down at the PICA, I'm gonna sew these inner layers, these two inner layers of vein graft here, arterial wall here together, running continuous. And that's gonna bring these nicely together. Same technique where the loops are placed, then tighten down at the end, tied to the node. And again, I saved the node at this end till things were secure and the suture line was placed. But now we can cinch it down, tie that down, and then we can run this outer anastomosis. So again, the second suture line for the insight to bypass pulls up and over the arterial autonomy so that it's a whole lot easier. So now we repositioned the temporary clips. We're perfusing now this trunk here, and we can go on to the third anastomosis or the second part of the bypass. So this year now is the temporal side for the temporal division. Here is the trimmed end of the vein graft. I'm also gonna use the insight two technique here because by doing that, I can shorten the window or the length of the graft, and I can just run this suture all the way around 360 and complete that. So now we've got, now we put our permanent clips on. That was a clip on the inflow. We've got a clip there on the M1. We've had a clip on the frontal side and a clip on the temple side. So now that giant aneurysm is completely trapped. We've got good flow on the bypass here along its course, but I'm not happy because one, one or two of the lenticular strides are trapped within those three permanent clips. So I've suctioned decompress the aneurysm. And as I repositioned this clip, I can free those perforators and this YELLOW 560 now will take a look down where those, strides were right here, and you can see I've freed them. I repositioned those permanent clips that backed them off of the frontal division, got them out, and now they're free, and postoperatively, now we have our double bypass. There's the donor site and the two connections. So an example of this double bypass or double reimplantation technique. Now last case, this is a, Dr. Spetzler showed some nice contralateral work. I wanted to show this for a more posterior contralateral exposure for an AVM. Here, to orient you, here's the tail of the, up here. The back of the head is here and the, lobe is down at the bottom of your screen. So the midline is here, falcotentorial junction is here, and the reason I'm doing this, I'm putting the AVM on the opposite side. And the reason is because the hardest part, the hardest margin of this AVM is gonna be going around that lateral portion of the AVM as it gets down into the atrium of the lateral ventricle. So to see the atrium, we wanna have that straight-line view across the midline and into the atrial region. So I'm cutting the faux. This is the straight sinus here running to torque yellow, which is way off in the distance. The top of the head is here. And as we skeletonized the straight sinus, what you'll see is that whole falcotentorial junction becomes freely mobile. And now here again, straight sinus, skeletonizing all the way down. And now that we can flop the falcotentorial junction away, we can get contralateral and we can pick up our feeders and veins here on the opposite side. So this now is the contralateral medial occipital lobe, PCA back here, the veins are going down to, and this is the tail of the splenium. And you can see how the faux holds the rest of the hemisphere up for us brings these feeding arteries that have been embolized very nicely into play. And now we can start our circle dissection, tell the splenium here, feed her from the piece from the pericallosals coming in. Here's the tail of the splenium again, we can pick up our splenial arteries coming in right here. And what's nice about these AVMs is that you can almost dearterialize the major stuff upfront. The ACA supply and the PCA supply are done very early on in the game. That means that as you now go around the, you really have a much quieter AVM. And so here, the AVM is kind of falling towards us, and this is the beauty of the contralateral exposure, because the hardest part is getting around this lateral margin. And you'll see here in a moment, I'm gonna enter the atrium right through here. And this gives you a straight-line view into the atrium. The ipsilateral hemisphere is here. We're working right over the cliff here of the ipsilateral side. We've entered the atrium, and it's an easy view to the lateral-most portion of the AVM. So what was originally the hardest part of this dissection becomes the easiest, and that is getting across here. If you came at the lateral, you would essentially have to go down the midline and then make a sharp turn to get around this plane, whereas with this approach, gravity pulls the AVM downward into your view, brings that, to you so that you can finish off these last remaining contributors on the lateral side. Now, with the preservation of the bridging veins, note the division of the, the preservation of the sinuses, and using gravity here to move this out of your way, and angiographically completely cured. Thank you.

- [Aaron] Now we have Dr. Bill Caldwell. Thank you.

- [Bill] Thank you, Aaron. So I've chosen a few cases. Each one, either to demonstrate a recovering from a complication or to try and prevent complications. This is an interesting case that it just took care of a couple of weeks ago. Maybe you can just stop it right there. So this is an extensive fibrous dysplasia case in a young woman. And she had an operation when she was younger where they whittled away at this, but they didn't really take care of it. And she suffered a very serious complication because it wasn't taken care of properly, and she presented with brain abscess. And I'm gonna show you this, treating her and then removing it properly. So she's got this extensive fibrous dysplasia involving all the anterior and middle anterior skull base here with this large brain abscess adjacent to it. So she came in very sick and she's got this orbital valve. She's got abscess in her orbit as well here. So what we'll do is, when they did it originally, the dural was never closed properly, and she ended up with sinusitis and now brain abscess. So we'll reopen their incision, and you can see what they've done. This was done by a plastic surgeon, they've whittled away and done all these different, they did partial thickness bone grafts and everything to try and reconstruct everything. So we'll get rid of a lot of this bone, and then immediately upon opening that, you can see the frontal sinus is a source of the infection that spread into cranially. And so this is, you have to drill this out. It's very easily, it's like drilling hard cheddar cheese, and it's very granular. This one is not very vascular, but it can be, but now I'm pulling the pieces out that are embedded in the frontal lobe. And you can see all the pus in the brain abscess adjacent to this. So what we'll do here is we'll just get rid of all this fibrous dysplasia. We're gonna decompress her orbit and removing all these mountains of fibrous dysplasia that are stuck in her frontal lobe. So this is the orbit, that's all involved. She's got proptosis as well, and you have to reduce all this. And so what I'm doing now, she's got that big plug that's in her orbit, and I'm removing this. And a simple matter, and you can see all the pus around this. So this immediately helps her proptosis. So you've got to take the time and remove all the diseased area. And so you don't want anything that's going to penetrate the dura like it did before. It's usually quite distinct so that you can get beyond it and find exactly where the edge is and remove it. It's also impinging on the left orbit as well. So now we're gonna go in and formally debris the rest of the abscess. So we'll open up the dura, find the abscess and just aspirate it. And then you'll have to go ahead and remove the rest of it, see all this extensive disease. And now I'm decompressing the left orbit. And so we'll take a fascia Lata graft, and now we'll solve the dura properly. And it's important to get closure all the way. I'm now filling all the empty dead space in the sinuses. We got right down into the nose and onto the hard palate, and we'll fill that up with fat. And then, so a vascularized pair of cranial flap in it's very tenuous in this case because it's a redo craniotomy. And so we'll go ahead and so this down as far behind your closure as you can write down on the plaintiff's Fino and Allie in this particular case. But this is really cleaning up from a complication of an inadequate surgery the first time round. And now we've also oversewn, and you can see we've drilled out the frontal sinuses as well. So hopefully we'll keep her from, and other complications similar. I didn't put back those pieces of bone and we had a cranioplasty made from the CT scan, and she's gonna have that replaced in a few weeks. This is her postop scan. Now you can see all the disease is gone that's impinging on her brain, and we've actually reconstructed the anterior floor much better. This is, yeah, this is a good case. Could you just stop it for a second? I'm gonna just show this case, because this is a hearing preservation operation in a little bit larger tumor than normal. And I'm gonna show you the technique that I personally use to try and optimize the nerve outcome in these patients. This is a woman with a left-side hearing loss and disequilibrium, and she's got heart failure, so we can't do an MRI. She's got a pacer. So this is her CAT scan here showing the tumor. I thought maybe this could be an aneurysm. We actually did a CTA on her, but it was a tumor. ABR at baseline, very good class A hearing. So I do these in the lateral position, and we do it through a small curved incision here. And make your opening. This is about a two-and-a-half centimeter opening. Open the dura, and then get right down on the tumor and find out where the IAC is. So we're gonna cauterize and open up a cuff of dura over the lip of the IAC so that we can drill out and get beyond the tumor early. So the important thing here is to make sure that you drill enough so that you can get clearly past the tumor. We always look at our scan before surgery to make sure that we're not gonna drill into the posterior semicircular canal. Here's the dura now overlying the tumor in the IAC. We're opening up that early. I like to do that to decompress the nerve early on in the dissection so when I manipulate the tumor, I don't squeeze it against the lip of the pores as much. We sound out with the facial nerve monitor to make sure we're not opening up into the facial nerve. We're not, in this case, the nerves on the backside of the tumor as usual. And then we're starting to gut the tumor with an ultrasound, a sonic aspirator. And then I'm gonna show you the technique that I use to peel it off the nerves. This is a very important instrument. We call this the wonder hook. It's actually an otology instrument. It's a very small hook, very, very fine. Now I'm peeling it off the seventh nerve here. And then the eighth nerve, you'll see a little bit to the left. And I use a small, soft, that we developed many, many years ago to hide and protect the nerve and use that as counter traction and peel up from medial to lateral, the tumor off of the nerve slowly. So the key here is to dissect and remove enough of the center of the tumor so that you can manipulate the wall and peel it up gently. So we'll continue to debulk the tumor and then peel it off the nerve. Now, this is on the eighth nerve itself. And we remove the capsule of the tumor as it becomes redundant and in our way, and then continue this maneuver slowly using countertraction with the small, over the nerve. So there you have it, the tumors removed, seventh nerve and eighth nerve laterally here. So we're just identifying the attachment to the supra vestibular nerve and we're gonna cut that. We'll wax the, any air cells that we got into. And then I like to put just a little plug of fat in here with some fiber and glue, just in case we have any micro-leaks that we didn't see and obviously wax the ourselves from the opening. And this can be closed. This size, a hole can be just closed with the large burrow hole cover. And we were fortunate enough to be able to preserve her hearing in this case. Nice watertight closure, and the ABR is still looks pretty good. And tumor has been removed. And you can see the amount of bone that we removed. We actually got into some, you can see that. This is a far lateral approach for a dural fistula, right where the vertebral goes through the dura. So it's a difficult location to get to. He presents with vertical gaze paresis. And his imaging shows the basilar artery here in a large draining vein. And on angio, you can see his right vert, you can see the fistula's connection here, and then an early draining vein. So a dural fistula right where the vert goes through the dura. So we can do a very targeted approach here using this curvilinear incision down a crease of his neck to get right down to the V3 segment and identify this. So this is the incision that we use. The key here is that the T piece of of C1 is just below the tip of your mastoid. And so when you get the patient positioned, you open up the skin and I go right away for the tip of the TPs. And you wanna separate the triangle of muscles, the suboccipital triangle that attaches there. So here we are now separating the vertebral artery from its J groove in C1. And we're gonna dissect out completely the vertebral artery from this location. Very commonly, a muscular branch comes off right here at the turn as it enters the dura. And then you've got to clean off all the soft tissue on the dura as it enters through the dura. We're drilling doing a Hemi laminectomy here at C1, and then we'll do a suboccipital craniectomy, a smaller one here to identify the dura, because we're going to have to cauterize, and what we'll end up doing is completely encircle around, circumferentially disconnecting the vertebral from the dura in this location. So the minute we open the dura, you can see the vascular supply here, very vascular. So take our time, cauterize. This is where the vert goes through the dura. And then we'll take a quick look and see if we can find that draining vein. So I'm just coming up just above the spinal accessory nerve here, and there's the draining vein. So we're cauterizing the dura all the time. It's very vascular. We'll cut C1 nerve here, and that gives us much war room. And then we'll go ahead and clip the distal, the draining vein. Now, it looked like it was more involved. So what we're gonna do is we're going to disarticulate and remove the vert where it goes through the frame of C1. So we're gonna mobilize the vert from the transverse framing, and pull that out of the way so that we can work on the backside of the vertebral artery better. So now we can go ahead and drill the comm dial a little bit, and then identify all this involved dura on the backside of where the vert goes through the dura. And so I'm cauterizing the dura and then we'll disconnect the vertebral artery circumferentially here from its dura attachment. And there you have it. So we're ready to close now, we've disconnected everything, our dura. And I close this far lateral approach in somewhat like a trans nasal operation, and that I use fat to bolster the opening, to obliterate the dead space and reduce the risk of a pseudomeningocele, 'cause it's very difficult, especially in this case, I don't wanna resew the Durham. And so we'll use fat and then close the muscle over the fat to hold buttress the area. And that's what it looks like. Fairly small incision. Post-op angio shows no more fissure. This is a 18-month-old child, that case of Doug Brockmyers that I helped him with. She presented with subarachnoids hemorrhage and hemiparesis. And she has a pretty significant subarachnoid hemorrhage, some intraventricular blood here. And we thought this may initially post-cerebral aneurysm, but when we did an angio, it was clear that it was a fistula with a large venous varix here that she bled from. So she had a ventricular drain placed since she had intervention color hemorrhage. And we'll go ahead and do a left temporal craniotomy on her and come in sub temporarily. Just a simple craniotomy placed centered over the middle fossa floor. We identify the fourth nerve at the tentorial edge here. She's got lots of subarachnoids hemorrhage, very hemorrhagic. And now what we'll do is we'll identify the third nerve and follow it back to the junction of the, and isolate the superior cerebellar artery in this case, and then follow this back and identify the large venous and the region of the fistula. Very small child, so we're going to try and do this quickly, try to reduce blood loss. You can see the rent where she suffered her subarachnoid hemorrhage, and we'll identify the region of the fistula and slowly cauterize and disconnect all the small vessels that are feeding into the fistula. Again, very vascular. It's a matter of just isolating the individual vessels feeding into it and then cauterizing them very well. Now we've got it down to a small pedicle here. We're gonna isolate these small vessels, divide them individually after we cauterize them, and remove the involved. And she had presented with a pretty significant hemiparesis initially, but she did very well. Ultimately, we were able to wean her ventricular drain. And we remove the fissure, take off the temporary clip off the superior cerebellar and the, and then close the dura, and close the scalp. Pediatric neurosurgeons always use absorbable sutures in the skin so they can avoid the painful part of taking them out. Here's the superior cerebellar and the post, cerebellar now free of fistula. Thank you very much.

- [Paul] I have to apologize, I actually, I put actual some pretty significant complications and not just complication avoidance, but so I think this will be somewhat interesting and hopefully not too, anything too bad here. There's a first case, there's a Vagal Schwannoma. This is a woman, is this playing? Yes, this is a woman, a young woman who presented basically with lower cranial nerve palsy in a familial schwannomatosis, and all of her lower cranial nerves nine through 12 at least are completely palsy and you see this very large Schwannoma, and the obvious approach here is a trans-mastoid approach with the limitation for anterior access being all was the facial nerve. She does have hearing, in this case, her hearing's intact as is her facial nerve function. Obviously we're working on doing a pre-sigmoid approach and dissecting down toward the neck. So here I'm stimulating the vertical segment of the facial nerve and dissecting out towards the stylomastoid frame, and obviously you can completely skeletonize and elevate the facial nerve in this area in order to gain better access in the pre-sigmoid space to the juggler framing, but this carries a very measurable risk to the facial nerve. This was a young woman who was very distinct about not wanting to have a, to avoid any facial nerve risk, even if it meant leaving some potential residual, so we did not mobilize a facial nerve. Here we're just performing the final resection of the jugular framing down to the frame and magnum. The posterior belly that gastric has been elevated, and as long as you stay anterior to the, digastric and C1, you don't have to isolate the vertebral artery here. I know it's sitting in this fat pad. And so here we're opening into the schwannoma itself. You can see we've completely skeletonized the sigmoid sinus as it goes down into the juggler bulb, which actually is still vaguely, deep to this schwannoma. So we're working medial to the juggler bulb here and just the, the tumor. Now, lower cranial nerves aren't functioning here. You can always make them function potentially worse, but she's really quite complete. It's a typical benign schwannoma, so has a reasonably good capsule to it. Here we see the posterior fossa dura once the tumor has been decompressed there, and now you can see the access that we had. And again, we're limited by the facial nerve and the fact that we didn't elevate it. So what we did is brought in an endoscope and working under that facial nerve segment, we're able to gain access really to the other half of the tumor. So here's the posterior fossa dura, and we're working below the facial nerve and out towards the carotid artery, the, carotid artery. I'm relying somewhat on the capsule of this tumor and knowing that I can peel the tumor in, but again, under direct visualization, I can see and ensure that I'm getting a complete resection without damaging anything inadvertently. Here's the superior pole of the tumor and just moving the endoscope around different regions. And now I'm starting to see here with a zero-degree endoscope, I can't really see very well up towards the vertical segment of the pair of pharyngeal carotid, just checking with my image guidance, to see him all the way at the depth of the clivus. And one of the things you remember is that sigmoid sinus was really quite exposed. I'm having to bring all my instruments in, in this window between the sigmoid sinus and the facial nerve. And one of the disadvantages of the endoscope is that you can't see your instruments as they're being brought in. So if I have my endoscope in the field here, it gives me this beautiful view here with an angled endoscope. I can see the schwannoma itself and I can peel it free. It's got a nice capsule here. So I'm appealing it free out of the distal end of the juggler frame and now, but I'm not able to really see where I'm introducing my instruments, so you have to constantly be aware of that and watch your instruments as you bring them in. Here's the final dissection of the tumor. And again, and then we're Doppler during the carotid artery. Here's the pair of pharyngeal segment coming up into the carotid artery, as it enters the skull base. And we're able to visualize this the whole time and use microsurgical technique the same way we would, but at the end, I'm bringing in image guidance once again, to sort of check all of these areas, I'm inspecting. You can see there is still some patency of the jugglers, I look in fairly and I accidentally injured the sigmoid sinus bringing instrument in. So this is an injury created by one of the disadvantages of the endoscope. So I tried a little, and I just a small muscle plug was able to control this. Here you see the postop, you see a little bit of blood product and fat, but a complete resection of the schwannoma, no more enhancing tumor. And you can see, I think there's a next cut here that shows the sigmoid sinus being patent as much as it was before you can see it's still filling. So this is one of the cautions with endoscopy when you're using it in a endoscopy-assisted fashion, is you really have to be very aware of all the structures around that you're introducing next to it. This next case also is I think showing a limitation of endoscopy. This is an endoscopic case in a 41-year-old man who presented essentially with Valsalva-type headaches, and this induced, from a relatively large extensive epidermoid tumor. You can see it extends all the way up behind the pituitary typical. Here you can see involvement of the PCA, PICALM and SEA on that side, and a typical DWI appearance. So we did a full trans clival approach, including pituitary transposition, where we stay extra dural to leave the pituitary within its a venous drainage and its blood supply. This is a nasal septal flap. It's a trans clival approach that gets placed in the sinus. I do wanna acknowledge my fellows, Dr. Chabot and Doctors, for the help, both with these cases as well as with the videos and putting these cases together, which is not a simple thing to do. So that was the right side of, and then this was just exposing the lower clivus. So here's the gland itself, the pair of clival carotids, and then all the way down to the frame and Magnum to expose this entire tumor. We can gain access even to some of the petrous bone in this case, and this using a needle tip Bovie just to remove some of the pair of pharyngeal tissue and the base or pharyngeal fascia to get down to the frame and Magnum. By extending below, we can widen our clival exposure, this so-called far medial approach, where we drill all the way out to the medial juggler tubercle can widen the clival exposure about 50%. Now here's the clival approach with a posterior clinoidectomy. And then skeletonizing the chronic gives me a little bit of access to the petrous bone here. And so this access to the petrous and the petroclival junction allows me to have a proximal control over the carotid. I can drill out bone of the petrous and I can do this pituitary transposition that sacrificing the inferior hypotheses artery. This is really a trans-cavernous sinus approach. And then I can carefully dissect through the posterior clinoid. And what this allows me to do is now the gland is free-floating, and I can elevate the gland to work up towards the upper clivus and. This is just stimulating ahead of time to make sure the sixth nerve is not pushed ventrally, and then accessing the tumor and starting to dissect the tumor here. So you can see the capsule is directly against the dura, so I'm sort of fortunate in that way, but as we sort of expected it to be, we can start to see the basilar come into view, have really an unparalleled view of the basilar here in order to gain access. And I, and again, using microsurgical dissection, this is that far medial approach that gives us access. You can see the lower cranial nerves because we've dissected the petrous bone here at the petroclival junction below frame in the serum, we can gain access much more laterally. Now here's the, access aspect of the tumor, there's tumor extending around the basilar, so have to use very careful microsurgical dissection. There's the left sixth nerve coming off at the vertebrobasilar junction. We've managed to preserve that. But you can imagine this is a very long exposure. It's a very long case, and it's relatively, technically challenging. And here, we're looking up now with an angle endoscope, it's about four o'clock in the afternoon now, and we're at the final aspect of the case. And here, I'm just trying to trim the tumor off of the SEA, and it's a simply generally one of those mistakes you only make later in the day, and I cut directly into the SEA trying to trim the capsule off the tumor. So one of the problems here, I don't have instrumentation that allows me to do some of the suturing you saw earlier in these bypasses. If you had an open access to this, at least I know Dr. Lawton, Dr. Spetzler would be able to put a 9-0 suture in this and probably keep patency in that vessel. The best thing that I could do here was either try to put a clip on it, or in this case, just seal with a bipolar, just the opening into it and hope that I can keep the vessel open. Now, because of that pituitary transposition, I could increase my dural exposure. So I have adequate exposure to this. I just don't have the instrumentation that allows me to control that. So here I'm suctioning free the residual tumor around that area. I'm Dopplering all the vessels. I did have some Doppler blood flow here, but this vessel did shut down. And here we see the postop with, well, I think quite a good resection, but at what turned out to be the price of that SEA, put a little SURGICEL on there to try to, again, maintain hemostasis, and then a multi-layer reconstruction for the clivus. We've gone to this inlay DuraGen followed by fascia Lata with fat to bolster to prevent a Ponting encephalocele. And then finally, of course, a vascularized reconstruction at the end. Did have a left partial six nerve palsy that completely resolved. In here you see that SEA and fat. If you can go onto the next case now. Well, it depends on if and where it does recur. I think there, if there's capsule left in this case, it would be lateral. And so in that case, I would do a retro mastoid approach if there were some recurrence there. I think the disadvantage to a midline approach obviously is the very lateral tumor. I probably can't cut capsule off of the lower cranial nerves laterally, and that's the most likely source for recurrence in that location. If you can play this, this is a 60-year-old woman who presented with diplopia, some very mild trigeminal symptoms and kind of unclear what this tumor was, I watched it for a long time, eventually she consented to at least a biopsy and debulking of this tumor. You can see is obviously largely in Meckel's cave. So here we've exposed, here's the gland, here's Meckel's cave, completely exposed through a trans-targeted approach to the maxillary sinus, the sphenoid and a partial posterior ethmoidectomy. There's infraorbital fissure and V2, and now I can open Meckel's cave and land directly on this tumor. This is using a Cartouche dissector named after Jack Cartouche, much like we would do, we used during, for example, pituitary surgery to stimulate. It's long enough generally to use endonasally, and I can stimulate quite well. So I'm able to do a dissection of the tumor. It's got a reasonable plane with the carotid artery itself, and here I'm just stimulating to make sure I'm not up on the sixth nerve. I Doppler the carotid to make sure I'm not impacting it. Seems to have a reasonably nice margin. So here I'm just dissecting the lateral aspect of the tumor. So it looks relatively like a schwannoma to me at this point, but one of the goals here, the two goals were to decompress the sixth nerve and also get a biopsy as well as get as much resection as you can. This is that Nico myriad device, which can be nice in a narrow corridor. And again, debulking the tumor and then extra capsular dissection using microsurgical technique, able to clear out Meckel's cave quite nicely here. I've pretty much cleared the carotid, so now I'm just seeing some attachments that frame in the serum. We've dissected it free, and now I'm waiting for pathology and actually had one of my trainees sort of testing the cartouche, and unfortunately that cartouche when he was testing, it ended up in the carotid artery. And so I was basically walking back in the room to see how things were going, and this is what I was met with. So immediately I place a Cottonwood on the artery, just like you would do with an open approach to have control over the bleeding, and then try to localize it better. Now, fortunately, I do have good proximal and distal control. We've gotten had wide access. So I put a proximal clip on the carotid. There's obviously a quite brisk back bleeding. We know from a preoperative CT angiogram that there's an intact circle of Willis. So one option you could contemplate here would be a sacrifice of the artery, but that's really not the goal here is to try to preserve it. You can see one of the challenges with endoscopy is the blood itself can obscure your field. It's very important to have a skilled endoscopy working with you that you've worked with a lot to be able to manage an injury like this. Here, I'm working with Dr. Snyderman. And so we have, we think, a control over the bleeding. We have our proximal control. It doesn't decrease the bleeding much. So I want to just try to get focal access to this point of bleeding and just pinch it off if I can, you. We can see the source of bleeding quite well. I have good visualization of it when it's not bleeding on the scope. And so I just wanna try to pinch this off. Here I'm gonna try and get a little more closer proximal control, and this is all realtime. The straight clip didn't work well, so I use just a 90-degree clip here to finally pinch off that opening in the artery. This is just a single shaft clip applier. It's made by Aesculap all the clip companies, I think at this point I know Mizuho makes one as well, and that really fits very well in the nose, but you do have to be a little more creative with your clip application. Here with Doppler in the artery to ensure it's open, I do, these patients whenever I'm dealing with an injury like this to prevent thromboembolism. And then of course at this point, I'm certainly not gonna do anything more other than close things up and go straight to angio, which is our next step. There's a last bit of the tumor there, just to be able to get a good fat graft around the aneurysm clip. This is one of the challenges. Fortunately, this is completely extra-dural. So I just wanna protect this and separate this aneurysm clip from the sinonasal cavity. So we place a fat graft around it. This dampens the pulsations of the artery on the aneurysm clip, which can wear through a nasal septal flap, which we've had happen, and then place the vascularized flap over it. And then of course, we'll go straight to angio from here. And so that that clip should be protected. And you can see actually the vessel, a little bit of subtle narrowing here, a little bit of regularity, but in pretty good shape and the post-op showing a nice resection. All right, if we can go to the next video then. All right. So this is also I think showing an interesting case, but somewhat of a limitation and difficulty. This is a very broad anterior posterior basial aneurysm. So difficult for coiling. You can see it's relatively low lying, so it comes up behind the pituitary. So I thought that we'd be able to access it again using this pituitary transposition through the upper clivus. So a straight midline endonasal approach. and we'll have to remove the floor of the clivus. And again, using this trans cavernous approach, going to the medial aspect of the cavernous sinus, I can gain access extradurally to the, and the posterior clinoid. By using a Kerrison, I can resect the dorsum in the midline, which splits the two posterior clinoids so I can dissect each one separately rather than when I'm dissecting this one, potentially compressing the other one into the contralateral artery. So here's opening the cavernous sinus, so it can have good access to dissect the posterior clinoid. And it's relatively tall posterior clinoid, so this really, I think doing an inter-dural dissection like this really gives me much better control of the clinoid to make sure I don't injure the artery at the same time. It's got a lot of, of course, dural attachments like you saw in the video of posterior clinoid Dr. Lawton showed from an intracranial access. And here's dissecting off the contralateral one. You'll notice the posterior anterior, has a very nice dural attachment around it. The posterior gland does not. And so it's much more prone to injury. So there's a greater tendency for at least some transient DEI, but essentially we leave the gland and its drainage intact. So here I've peeled away the periosteal layer of dura, which gives me a straight access to the meningeal layer of dura. I can then open that without bleeding from this basilar plexus because I've completely, the basil plexus lies between the periosteal and the meningeal layers. Here's the dural opening. And then exposure of the aneurysm. We have a pretty nice exposure, but one of the challenges is I can see very nicely the apex of this basilar aneurysm, but applying clips, I have to be very creative with. So here, I'm dissecting the neck. It's a relatively small aneurysm, it has a fair amount of turgor, and I think upfront here, I would have been better off trying to place a temporary clip to release some of the turgor. I tried to place a, I wanted to place a shank clip across this because of the anterior poster dimension of it. This is an initial clip, and because of turgor on the clip itself, as I apply it, it simply slides up on the aneurysm itself, and it actually ended up clipping down onto a small perforator off of the back side of the PCA here. And so I can't just pull this out because it's actually clipped on a perforator. Fortunately, I checked for that. So what I end up doing is placing a temporary clip here because now I need to work around the dome of the aneurysm. And this is the challenge when you're working in a nasally is as soon as you place that clip, it now flips into a different direction. So it's great when you're applying a single shaft clip applier in and out of the nose and the clip stays in the same trajectory, but now it's flipped up in this direction, I have to hold it with one instrument and try to redirect it into my clip applier. And so this is in some ways a limitation of the instrumentation, but also a limitation of the corridor. So this becomes very challenging to get that clip into the, I can't find a different corridor. I have two nostrils and so I have to really angles to get into this. So now we'll do a temporary clipping to decrease the turgor in the aneurysm, and here's that shank clip. So it's a bayoneted clip, but the heel of it acts as the anterior to clip off the anterior aspect of the aneurysm and it shanks around the neck of the aneurysm. First clip placement is an ideal, but fortunately I'm in line with that clip, so I can replace it. And again, some difficulty removing the clip because, again, it flips in a different direction. And so this is definitely one of the challenges. So I'll have to replace this shank clip. If you can just fast forward a little bit. So replacing my temporary clip, replacing the shank clip. Finally, I get a nice shank clip on place, and then I placed a second fenestrated clip to clip off the posterior aspect of the aneurysm, because it's a very big bowl anteriorly, and then when posteriorly, I can place this fenestrated clip with the endoscope. It does allow me to see those blades as I placed them with this fenestrated clip, which is, the fenestration is around the shank clip. And here we can see the clip and nice position on both sides of the basilar and postoperative result. So this patient ended up doing quite well. She was a middle-aged woman. She didn't really have a, she had a partial third nerve in the post-operative period, but resolved it completely and has gone on to do quite well. But I think these cases do illustrate some of the advantages, but also some of the potential limitations and complications you can have a working with an endoscope. This is of course the reconstruction is a challenge as well and one of the potential complications, you really have to cover this completely with fat around the clips and then a multi-layer reconstruction. All right, thank you.

- [Aaron] I have to mention that doing clip application through the analyzer approaches the final part of a learning curve in endonasal surgery, and obviously requires extensive amount of technical expertise. And obviously, one should not in any way, and we personally do not recommend anyone trying it without absolutely significant experience with endonasal microsurgery. Go ahead. What was the question there?

- [Paul] So the question is why not an open surgery or an endovascular surgery? Sir, the patient was considered for endovascular surgery. It was felt because of the broad anterior posterior neck, that there was a high risk that the patient would need stent coil at very least if not stent in-stent coiling because of the width and the broadness of the neck. And the patient actually was, we have for endovascular surgeon, it was discussed and it was felt that it was a reasonable given her young age also then to offer her a clipping of it. Now, why not craniotomy? That certainly is the standard of care for this. I felt that I could appropriately and safely treat it and I was fortunate to be able to do so. I don't recommend, I don't, I'm not trying to say this is a way they should be treated. This is partly I was trying to see what we're able to accomplish, what are the things that we can do? What are the limitations? We've avoided disasters with clipping in this way, but I think it does have the advantage of giving me proximal control. I have very direct view of the aneurysm, but it does provide significant technical challenges. So I think it's appropriate to question it and that's, I don't claim this as being the treatment paradigm for this.

- [Participant] Well, how can we be sure?

- [Paul] Well, you can see the perforators. You can bring the endoscope in and look at them, but you're right, from a lateral approach, you see the perforators as your place in the clip. There are definite advantage and disadvantage to it. I agree.

- [Aaron] I agree with you, these are very reasonable discussions, but for the sake of time, I wanna thank everyone, including our faculty, I wish you a great rest of the meeting and happy flight back home. Thank you.

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