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Nuances of Technique in Cranial Surgery: AANS 2016 Monday Operative Session

Frederick Boop, William Couldwell, Juan Fernandez-Miranda and Paul Gardner

July 12, 2016


- [Aaron] My name is Aaron Cohen. Thanks for joining us for the Monday afternoon 3D sessions. We have a very exciting set of speakers. First one is Dr. Rick Boop, our president. Rick is a dear friend and as I've always said, the best most technically gifted pediatric neurosurgeon I've ever worked with and have seen many times him work. And second we'll have Dr. Bill Caldwell, truly one of the top three master surgeons ever created in neurosurgery. And we'll follow up with our other colleagues, including Dr. Paul Gardner and Dr. Juan Fernandez Miranda, pioneers and equally gifted surgeons in indoscopic surgery. So I wanna thank all of you for joining us. And I would like to ask Dr. Rick Boop to start our first set of videos. Thanks again.

- [Frederick] Well, thank you, Aaron. Everyone can hear I hope. And so let's see which of these, I've got four cases to go. This first one is a baby who was born with a lump of fat just above the sacrum. And if you could pause just a second there for me. Led to this MRI showing this fatty mass in the midline, there was a defect in the sacrum and this fat extended down through with a tail of fat coming into the dura and then intrathecally, as you see here. So this is a light pomelo, meaning a seal, and we categorize those as dorsal if they go through a defect and attached to the dorsum of the cord, transitional if they attached to the epicomus and then terminal if they basically are a stock of fat replacing the phylum terminality. So with this one being a transitional type than we would expect to have a separate file interminably. And in un-tethering these children, we have to cut that as well as debulk the fat. So we think that a dappling pang has taught us that these are probably a failure of disjunction when the flat sheet of ectoderm is rolling up and forming the neural tube and the cutaneous ectoderm has to separate from neuroectodermal. So typically these will insert at about the dorsal root entry zone. And this child obviously was recognized at birth, we were trying to follow and let the child get older and about six months of age, the urologist told us that the child was developing bladder instability, some detrusor sphincter dyssynergia, and that moved us forward with the surgery. So if we could continue, please. Otherwise a neurologically intact infant which was a bit worrisome. So what we've done is a replacement laminate plasty. The dorsal construct is elevated, this is that stalk of fat penetrating the end of the fecal sac here. And we're transecting it getting it out of the way at that level. And you can see the fat growing through the dura there. So now we're opening the dura and you can see that this fat pretty much fills the fecal sac and bulges a bit when we opened the dura and we got a little bit off to the side there, so we ended up using micro scissors to take it up to where we saw the junction between the a lipoma eliminating seal and the normal spinal cord here. We're resecting arachnoid, and you can see the rootlets here, the fat here. So, as I said, typically, these will insert at the level of the dorsal root entry zone. So if you stay in the fat, typically you're above the motor roots. This is just cleaning, cleaning off the arachnoid. And then look at inspecting the root, you can see here, the thick and phylum terminally, the phylum is always a different color and texture from the adjacent nerve roots around it. So if you're ever having to cut phylum terminally, you can tell by looking, it's all always obvious. You don't really need stimulation to tell you that it's not a nerve root, because there's no way to confuse this with a nerve root. And because it's got vascular supply to it, then we'll typically coagulate it, which always makes it contract so that when we cut it, you can hear the twang as it springs apart. Here we're taking the fat away from where it penetrates the defect in the dura. They always have a defect in the quadratus lumborum fascia through which they extend that is a variable size as well. And then here separating that fatty stock from the underlying nerve roots, here's where we get to the conus. You can see the remnant of the phylum here, and it's not dissecting away well, so this is where we bring in a KTP laser. This is a contact laser that I like to use because number one, it's hemostatic, number two, it doesn't char the fat, so we still have a nice visual cue as to what's fat and what's not, I apologize for the interference, our laser wasn't, our filter wasn't working well on the microscope that day. But we amputated that stock of fat as you see here and then the rest of the time just are de-bulking this fat, trying to minimize manipulation of this infants conus. And typically we get to a point where there's a blending between the fatty elements and the neural elements. There's kind of a fibrotic playing there, and that's typically where we'll stop and leave some behind. And so we next close the dura, put the laminate back here. She is a month postoperatively, bladders back to normal, and as best I can tell, she's still neurologically intact and no more lump of fat on the back, but hopefully this scar will look better over time. So this next child is an interesting case. It's a little girl who first came to us from El Paso. If we could pause the slide here once, if we could pause here. Presented with a fairly subacute two to three week history of progressive peripheral facial nerve palsy on this side and was found to have this exophytic brain stem tumor. So at the age of three, John Robertson and I approached this from a retro Sigma approach with neural monitoring facial and seven and eight nerve monitoring and de-bulked what we could until the auditory signals started to deteriorate, then we stopped. So if you could continue next. Go ahead and continue the slide. So she was asymptomatic for seven years and her scans were stable until this year when she came in with this scan. Well, this is her old scan. So pilomyxoid astrocytoma was her diagnosis at that time. So benign tumor with a more aggressive element to it. And then she comes in in February with an intranuclear ophthalmoplegia, which was fairly sudden in onset. It came on over about two weeks. At this time you see a large cyst with an enhancing cyst wall. So this is rostral, this is caudal, this is cerebellum. And our intent was to approach this through the floor of the fourth ventricle with curative intent. So we're elevating the left cerebellar tonsil here. You can see discoloration and a loss of normal architecture of the floor of the fourth here. And then opening up this cerebella medullar fissure, not resecting vermus but opening the fissure to allow us to get all the way up to the aqueduct without having to resect any normal cerebellum. And once we had adequate exposure, then bringing in a stimulator and stimulate. So you can see the floors kind of flattened out here. We're using the stealth to see where we are in relation to the system of the surface, then stimulating. So left fish, facial click, this was over here, right was pushed across midline, we got a response from the lateral rectus. Six nerve was stimulating up at this level. So decided to come down low and staying four or five millimeters to the right of midline to avoid the MLF medial longitudinal fasciculus. You can see the capsule of the tumor just under the surface here. And this was quite a tough fibrous capsule. So we were actually able to grab a hold of it and use it to dissect that enhancing cyst wall away from the brainstem then opening the capsule and using the ultrasonic aspirator at that point to debulk the tumor. You can see the typical gelatinous appearance of a low grade glioma clearly distinct from the adjacent brainstem tissue around it. And using somatosensory evoked potentials, brainstem evoked potentials throughout this portion of the case. Eventually getting to the point where we thought we'd gotten all of the solid tumor out and all of the wall out, and then proving that we could still fire the facial nerves and the lateral rectus with stimulation from the floor. And then drying up and just cleaning up, removing anything that looks like remnant of tumor. And this is a case where we've found the use of our intro-operative MRI to be very helpful. It's not uncommon for the focal brainstem tumors to require two or even three intraoperative MRIs, but you can see in the prone position here, we think we've got a clean resection cavity by T2 T1. And you can see on coronal and sagittal enhanced scan we don't think we've got any residual tumor left. Her brain stem evoke potentials did drop to just about just above 50% of that amplitude. And this is six days post-op just before discharge. You can see her neck is still stiff from the incision, but a motor function is fine. She still has residual internuclear ophthalmoplegia, she can look to the left and she can look straight ahead, but she still has trouble crossing midline. She gets double vision when she looks all the way to the right. But you can see her face is still working fine. So we're hopeful this pathology came back this time as a pilocytic astrocytoma. And there are occasions where in young children they'll have pilomyxoid histology but it'll mature and net recurrence, it will be a pilocytic astrocytoma. So we're hopeful that she's cured and won't require any other treatment. I'd like to give credit to Ryan Foley, Kevin Foley, son for editing these videos for us. If we could pause the video here, just a moment, please. So this is a child who was referred to us from across the state, and this is a case of what we call a growing teratoma syndrome. These are children who present with a mixed germ cell tumor. That is a germ cell tumor that's got both malignant and benign elements in it. So at presentation, he had elevated alpha-fetoprotein and beta HCG, was treated with chemotherapy on that basis. And his fetoprotein beta HCG went to undetectable levels, but the residual tumor continued to grow. And typically what continues to grow is the mature teratoma element of these tumors, which doesn't respond to chemotherapy, it doesn't respond well to radiation therapy and to my knowledge, the only way to cure these is surgically. So at referral, he was cachectic, he was a tube fed, he was unable to open his eyes. we don't think he was able to hear if he could hear, it was with impaired hearing, but he would speak, he would verbalize. And when he was stimulated, he would demonstrate decorticate posturing. So a very unusual presentation. If we could continue, please. So you'll see on his imaging, a large cystic and solid pineal region tumor completely compressing the tectum in midbrain, extending up almost to the corpus callosum here. So these are typically firm, they often don't respond to ultra spot sonic aspiration so our best approach is a trans-clozel sub-croyle approach for these, where if you need to, you can cut them out piecemeal with scissors. So here's the midline, we've pulled the dura over across the midline, one bridging vein we had to sacrifice which is not large. And you'll notice that we try to avoid using fixture tractors in all these videos. I don't think you'll see a fixture tractor at all, we gave up using them about 20 years ago. So once we get through the corpus callosum, normally the first thing we'll come to are the internal cerebral veins once we open up the choroidal fissure, in this case, the tumor had splayed them out laterally, so can see internal cerebral vein anteriorly here stretched around to that side. So here's a component of the tumor that is soft and gelatinous and can be removed with ultrasonic aspiration. But most of the tumor is this firm leathery connective tissue with areas of bone in it. This is the internal cerebral vein stuck to the tumor capsule, you can see us dissecting it away here. And typically the foreigner sees are out lateral to the ICVs. So piecemeal dissection, this is the atrium of the lateral ventricle, and there were contributions to the blood supply of the tumor from there that we had to take out laterally. Then following it back around to the flattened out midbrain underneath and taking the feeding vessels, this is the right internal cerebral vein. And we took a long time to dissect it out all the way to the back of the tumor where it was occluded by the tumor and probably a waste of time. But you can see the tumor coming out here. And this is the fourth ventricle we're looking down into from there. So inspecting the cavity making sure there's none left behind at the end, brain looks pretty good and he woke up to be a much better child. So here he is, mom sent me this cell phone video recently.

- Look how good am doing.

- [Franklyn] He says, "Look how good I'm doing."

- I've been doing so well, thank you for fixing me.

- [Franklyn] So in his pathology, all the elements were matured teratoma, so no need for chemotherapy or radiation and he should be cured. This last case is a child, a five-year-old who came up to us from Houston recently. He presented with hyponatremic seizures and this large super cellar tumor, cystic and solid, his SIDH was probably from hypothyroidism. And once we started him on steroids that unmasked, the glucocorticoids unmasked is diabetes insipidus. So you see a super cellar tumor with the kayak zone postfix, which is a bit unusual for these craniopharyngiomas. In his case, I'll mention that his alpha fetoprotein was 11, which is upper limits of normal. So we weren't sure whether this was going to be a germ cell tumor or a cranio, although by imaging we'd favor craniopharyngioma. So fox is pulled over, we're separating the two frontal lobes coming in anteriorly, identifying the anterior cerebral arteries. This is the gender of the corpus callosum, the anterior cerebral is coming around here, the anterior communicator and the tumor cyst capsule coming into view here. To pull this is Kim Foster helping me. Did you. We dissected this leather capsule out as much as we could before we aspirated in the typical motor oil color of fluid of a craniopharyngioma. Then you see here, the chiasm which is very densely adherent to the tumor capsule. So we start in tier two, it trying to dissect it off without using a much blunt dissection, because his vision as best we could tell it was intact pre-operatively. This was a knuckle of tumor that extended up to the lateral ventricle that we were able to pull back out and around taking a little feeding vessels here. And this is a spectacular micro dissector. It's a beautiful set of curates that he's produced that are great for dissecting tumors. They're sharp on the sides, but cup shaped. And I favored them a lot. So dissecting the left optic nerve on around to the side there. You can see that nervous pretty flattened here. As we dissect it away, you can see lamina terminus in the distance. This is chiasm here, left optic nerve over here. And then following it around to the right and dissecting the right optic nerve away from the tumor next. So it's getting bulky enough. It started getting our way, at that point, we cut up an opening and the tumor capsule and took some biopsies and then started to debulk. Yeah, I should mention that we're standing, we're using what we call a four hand technique, we have two oculars facing each other standing side to side across the patient, that's why you can see four instruments in the field. This is the undersurface that causes a little bit of extra epithelium stuck on the underside that we resected here and getting down to the level of the cell and the depths there and the tumor on preoperative imaging looked like it invaded the cavernous sinus' bilaterally, but did not in case the carotids, it was about 180 degrees around the carotids, but not in casing. So you see this thick leathery wall, you can see why sometimes people have trouble placing stereotactic catheters into these big scissors when the walls' this thick. And then de-bulking with the ultrasonic aspirator. And here's tumor capsule coming up out of the cellar, trying to open up the plane between the dura and the tumor sharply and then dissecting it out of the cell as we go then de-bulking using the stealth to tell us when we're adjacent to the carotid tier and eventually removing everything that looked like obvious tumor, and then coagulating the floor with the bipolars. So again, here's our MRI. We are a bit concerned, this is the chiasm and there's still a little streak of enhancement on the undersurface there although we thought we got all that loose. So we'll have to keep an eye on that. But aside from controlling his diabetes insipidus postoperatively, his vision seems to be as good as it was at baseline and he's he's out of the hospital doing well.

- Thank you, Rick, truly a work of a master surgeon. These cases are very unique and obviously extremely challenging. Before we go to Dr. Caldwell, I just wanna take a moment and thanks Zeiss Meditech, Deidre Watson Dorf, who is sitting right behind me at the table there, has done an instrumental job to make these videos work so well and seamlessly in a 3D fashion. So I wanna truly thank Zeiss for being such a strong supporter of neurosurgical education as they always have been. And specifically thank you Dorf for spending such so much of the evening and this morning to make sure everything works well.

- Thank you very much Aaron. I've chosen a few cases. Could you just hold on for just a second? Thank you. The cases I've chosen have all been chosen for to demonstrate a surgical principle or a technique, or to help promote a cause as in the first case. Now this is an old operation that's actually being re-polarized right now. And it's an intracanliculur tumor in a 55 year old man with left sided tinnitus and recent sudden hearing loss. And it's a small intracanliculur acoustic tumor. And the reason I'm showing this is that we've just, we're just publishing a large series of these patients with 75% hearing preservation with this approach, which exceeds the natural history and also radiosurgery. So I think it's something that we should be paying attention to. So this is done through a middle fossa approach. And the reason for that is it gets you out to the fundus of the canal, very beautifully as you'll see in the video. So it's a simple temporal craniotomy that we make it about four centimeters and we center it over the root of the zygoma, which is right there. And then you come in sub temporally and dissect sub temporally, the middle fossa floor. So here's the bone flat being lifted off. And then we come in a sub temporally and peel off the dura from the middle fossa floor. So what I'm doing here is I'm trying to identify GSPN, the greater superficial petrosal nerve, and then once we identify that, we usually cauterize and cut the middle meningeal artery, which is just lateral to the frame in a valley. And this usually then gives us enough room. And now what you wanna do is you wanna find the arcuate eminence and GSPN and you bisect that line. And that's where you're going to find the IAC when you drill, that's Darryl Brachman's line. And so Cloth now is drilling and finding the IAC. It doesn't take long, it's usually less than a centimeter down to find the IAC. And then when you drill off the IAC, you want to drill it off more than 180 degrees. And the reason for that is because when you start dissecting the tumor out, you don't want to push on the cochlear nerve and cause injury to the cochlear nerve. So one downside of this approach is that your facial nerve is lying on top of the tumor from this approach. But I find it very simple on these small tumors to dissect the facial nerve off the tumor. So we're opening up the dura now and you see the tumor with a facial nerve lying on it. So we'll cut the dura away and then define this plane between the facial nerve and the vestibular tumor. So we'll, de-bulk it and then we'll develop this plane between the facial and the cochlear nerves below you. You don't see that until the tumor's almost completely removed. So you rotate the tumor up from medial to lateral and gently move the facial nerve anteriorly here. We'll, de-bulk more of the tumor And then rotate the last piece of tumor up here And then identify the vestibular nerve that it's attached to and cut beyond the tumor. And then once you see it now, now you'll see the cochlear nerve which lies right below the facial nerve and posterior to it. You wanna wax all the air cells in case you got in with the approach, we put some fat in where we've drilled the IAC in case there's a small air cells that we can appreciate, put some fibrin glue and close up. Very quick operation, takes about an hour and a half. And we do ABRs during the case. And it's a beautiful way to be able to preserve the hearing. You could say, "Well, you could do this retro sic." and we certainly do it retro sic, but it gets you out to the end of the canal much better. So here's the post-op and the tumor has been removed. So just to remind you that that's an operation that you can do if people have a stippler symptoms and they're losing hearing, it's a great way to go, with durable hearing preservation. Now, the next case I'm showing to show an approach. And this is a approach that we developed a few years ago now, probably five years ago for approaching the cavernous sinus. This is a woman without ophthalmoplegia, she had had a bone marrow transplant. Now she's got this enhancing lesion in the cavernous sinus. She's had a bone marrow transplant for leukemia. And so the oncologist thought this was probably a recurrence of leukemia so we were planning to just do a biopsy of this. Now our philosophy is if it's medial to the carotid, we'll certainly just go endo nasally and remove it or biopsy it. But this is lateral to the carotid and we'll use a little Orbital tummy approach, that's very quick to biopsy this lesion and decompress the lesion. Could you run it please, Gheto? Thank you. So this approach is designed to come right beside the orbit underneath the temporalis muscle. And so we put an eye protector and then I usually fork this little incision just to give us a little more working room, but basically you're putting the incision right into the lateral canthus of the eye. And you dissect right down on the peri orbita of the orbital rim and expose about a centimeter and a half of that orbital rim. And we use a C1 bit, so we don't remove too much bone and then make a side cut. And you want to remove just over a centimeter of a window here. We usually drill for plates right now, so that we guarantee that we put it back in where it was before. So we don't have any cosmetic problems. And then we'll remove the lateral orbital rim, like a little bone flap just to undercut it with a chisel and then remove it. And then what you're going to do is you're gonna drill down through the oterion opposite to where your direction that you're usually used to. And you stay extra directly underneath the temporalis muscle and you lift up the dura off of the cavernous sinus. And in about 10 minutes, you're right on the lesion. And here's the lesion, you can see it, clearly not a leukemic infiltrate in this patient. So the tumor was quite fibrous, which was a little unusual and was not what we were expecting. So we went ahead and removed the tumor and the closure is really straightforward because you have an open dura. We just replaced the bone, lift up the retractor from the muscle and closed the subcutaneous tissue. And so we've used this operation for meningiomata and for decompressing the cavernous sinus with meningiomata that are symptomatic. And it's very simple and very fast. This was a case actually it's being published, it's a very unusual case of an EBV associated with smooth muscle tissue. It's a consequence of a bone marrow transplant, but completely unexpected in that location. This next case, could you stop it for a second Gheto? So this next case I'm gonna show you is a sort of a call to arms. and the operation is a bypass from the subclavian artery to the vertebral at the V3. And the reason that we're doing it is the woman has bilateral vertebral occlusions. And Fatty Sharp Ballon is group in Chicago here published a very important paper a couple of months ago, demonstrating that if you have somebody who's symptomatic from vertebrobasilar stenosis or occlusion, that you can help them, you can select them and you can reduce the risk of stroke because you can identify high-risk stroke candidates by using his ML algorithm that he uses to select people who have insufficient flow to the posterior circulation. So I think it opens up a whole new day of posterior circulation revascularization that we've kind of dropped over the last 10 or 15 years. Gheto if we can go ahead, please. Thank you. So this is a woman with bilateral vertebral artery occlusions. You can see the left is occluded but reconstitutes up here with muscular branches and the right reconstitutes by muscular branches and V3 is open here. So what we're going to do is we're going to re vascularize her from the subclavian artery to V3. And now V3 is a perfect place to sew an anastomosis because it's quite simple to do. And this is a fairly low risk bypass. So we'll do two adjacent incisions, I like to do a linear incision here, just a curvilinear incision to get down to V3. So we'll harvest a saphenous vein in this particular case. You can size this saphenous vein on the leg where you want to take it by using a preoperative ultrasound and trying to match it to the vessel that you're trying to replace. So you can do that and pick the position on the leg where you take your vertebral artery from. So we'll harvest the vertebral artery, you can do it also too with the radial artery. We'll harvest this after this saphenous vein here. And then we'll go ahead and expose the subclavian, which is a very simple thing to do. You just come underneath the subclavian vein just below the clavicle and you move the subclavian vein superiorly and identify the subclavian artery. So there's your subclavian artery. That's what you try to avoid when you put a central line in. And then we'll do a V3 exposure. The key here is to find the transverse process of C1, to feel it with your finger and that tells you exactly where the vertebral artery is. That transfers process of C1 is just below your mastoid. And you could feel it on yourself if you feel. So we'll expose V3, we'll prepare the vein graft, we'll run a tonsil clamp between your incisions, I like to bring a chest tube through and use it as a sion passer. So we'll identify the V3 segment, we'll clamp it off, and then we'll go ahead and perform the distal anastomosis. I like to use interrupted sutures and the real reason is I don't cinch the incision or the anastomosis when we saw it. It's a simple thing to do, it's a very easy bypass to do in that location. This is the proximal anastomosis, we'll use the thyroids cervical trunk here, we'll size the graft, prepare the end and do an antenna anastomosis from the thyroid cervical trunk. You just clamp it off, clamp off that segment of the subclavian, it's very well tolerated. Again, interrupted suture and then we'll go ahead and back bleed and then go ahead and open up the anastomosis. The beauty of this particular bypass is that you don't put your other carotid at risk because if you bring the interposition graft between the carotid and the vertebral, you put the carotid at risk, that's feeding the brain. And so that's what it looks like and postoperatively here's her bypass. And she did well and her symptoms went away immediately. And the last case is a very unusual case that I'm going to show you. And maybe we can just wait until the images show up Gheto. So this is a case of a very unusual indication for surgery, but we have a series of these patients. This is a 46 year old man I followed for many years. He had a craniotomy many years ago for this disease, but this is very unusual and you'll see what I mean. His brainstem looks like Swiss cheese, and this is a veer corobin spaces, could you stop that? And so what what's happening is the veer cover where the vascular penetrates the brain occasionally you'll get cases where the patients will develop lobulated cyst and they can get very large. And we've had them in the brain and in the brainstem, mostly in younger people. And this patient was becoming very symptomatic. He's a farmer from Washington state, and he's grossly symptomatic from this lesion. And you can see the size of these cysts, so he can hardly walk at this point. So what we're gonna do is we're gonna do three different trajectories into the brain stem to drain these cysts. The first one, we'll do a Tilo Vilar approach, and we'll come in through the fourth ventricle in a similar way to what Rick just showed you with that JPA. So standard suboccipital craniotomy, and then we'll come in and do a super facial approach above the facial nerve nucleus to the brainstem posteriorly initially. So open up the arachnoid Tilo Vilar approach. Here's the caudal loops of PICA here and we'll go ahead and then come in Tilo Vilar and show ourselves the floor of the fourth ventricle. Cory plexus, so we'll map out the fourth ventricle, you can see the stream megillah is down below here, and we're going to come above the facial nerve where it stimulates and go in the superficial triangle and get into all those cysts. And we'll finish straight multiple assists that through this one approach. And then we're going to bring him back and come in above and get more of the cyst we do this a few days later. So we close up and then this is a med port cranioclasty we use, and then bring him back through a retro sigmoid approach and do two other separate approaches to the brainstem through the retro sigmoid approach. So I like to do these patients lateral, you pull the arm down, it gives you much more room between the shoulder and the neck. This incision that we use is this S shaped surgical incision, it keeps the muscle out of your way. And then open up. This is right, the trigeminal area here between the sigmoid and the transverse junction. And then this gives us an approach, both retro sigmoid and super cell or beller you'll see. So I'm in coming in retro sigmoid here, and we're going to come in right between the root entry zone of the seventh nerve and the fifth nerve. So the root entry zone or the fifth and the exit zone of the seventh. And so we're going to then finish straight cyst through the peri trigeminal region, just below five in line with where seven is. Then we're going to come in and slip now above the cerebellum and go into the midbrain. And so we identify the fourth nerve here, you can see it coming into view here, and we're going into the mesencephalic sulcus and we'll identify that. And then penetrate that to drain more cysts. This is the lateral mesencephalic sulcus, just behind the parameter tracks. And again, we've got a beautiful view now and we can drain that big midbrain cyst that we had initially through all reasonable entry zones, and we've been able to drain all of the cysts through these approaches. That's what the closure looks like just through a simple burr hole, and I'm a broke cover. And there's that, if you make the incision in the same direction, you're looking, you don't have to worry about the muscle, spreads the muscle on your way. So here's the postoperative scans and he was significantly better. So I thank you very much. I think that was it.

- This is a 56 year old male with an incidental sort of a saccular fusiform aneurysm. You can see the aneurysm has a very broad base. You'll see more as we enter the case, how VM2 branches essentially originating from essentially high in the mid body of the aneurysm, a standard technique for exposing the sylvian fissure. Obviously the M1 has exposed.

- This sounds much better.

- So thanks, Ghetto ahead please. So here's exposing this aneurysm that's relatively fusiform, you'll see that the VM2 is starting really way close by to the dome. Let's go ahead and put a temporary clip to inspect everything well, you can see all, make sure it's all the way across the neck, and definitely not necessarily bringing in more flow in at least in that direction. Let's go ahead and study the morphology of the aneurysm a little bit better stuck to the temporal lobe. We'll go ahead and dissect that a little bit. These are aneurysms that most likely are gonna be the only ones that are gonna be, if any, of amenable to microsurgical techniques because of the advancements in endovascular neurosurgery. Here is a better view of how this aneurysm is relatively fusiform. There's really no neck that I can place it clip on. And so I find myself somewhat struggling right now of what's the best way to clip this aneurysm without living residual pathologic vascular wall behind. Here's looking over the dome, you can see VM1 from the other side now. I'll go ahead and do aneurysmal Raffi, something Yasha talked about years ago, still quite useful when necessary, because then I can fashion a clip to local over this without necessarily leaving some net could behind. So I try a curve clip, that doesn't work, I shrunk the aneurysm more UCI stay away from the neck and just shrink the part of the mid body of the aneurysm. Here's using an angled fenestrated clip to go over the dome close part of the aneurysm and here you can see some residual neck left behind from the other M2 can see this M2 coming from the neck, that part of the aneurysm looks well excluded. Now we have to manage this part, we'll put a straight clip. I bet there's gonna be some more flow through the aneurysm. At least all the feeding vessels or branching vessels are patent, I'll place in other clip just where I thought there will be some flow into the fenestration here's ICG, We use Floyd Hundred, it's a new technology that determines the, not only just absence of flow, also the intensity of the flow relative to the surrounding vessels. So you can see that everything is in a very red spectrum, that means it's feeling pretty quickly. So even though there's flow, I haven't compromised anything just because of this very complex vascular construction. Here's a fuller scene angiogram shows the aneurysm is good excluded but as you wait, it's filling in a delayed fashion. And that's one of the advantages of fenestration that just gives you such high definition assessment of the flow that if it's filling in a delayed fashion, you can be aware of it and manage it adequately. Obviously, managing this part is relatively easy, I just put another small clip that I thought where the aneurism will fill in distally and other small clip, again, the flow shows all the perforating vessels are intact, and as you can see, the aneurysm is completely excluded without any compromise of the surrounding vessels. This is an interesting case, "Accessory" Anterior Chordal Artery Aneurysm, unusual case, 32 year old female complaining of headaches, can see this aneurysm from the posterior carotid wall, somewhat sausage shape. We'll go ahead and open the Sylvian fissure again, using the inside to outside technique. I'll follow the M1 toward the bifurcation. Again, this aneurysm saw it unusual because there was some question about how related it was and to the cortical we used direct cortical stimulation for assessing motor fibers and descending tracts. Again, no fixed retractors as you can see as used, dynamic retraction have very high magnification. I intentionally operated at exceeding the high magnification because I think that trains you to be a better surgeon in general with using the microscope at its full potential. So here's the we'll go ahead and dissect along this menial segment of the sylvian fissure, here's the carotid artery. Now we have to somehow find this aneurysm see how it's related. It's a beautiful anatomy of the perforating vessels from the IC bifurcation, not coming along the P com you can see there's no aneurysm there. So this aneurysm is now a true intra-quantal artery aneurysm. The neck is probably somewhere here. If I can have another laser pointer with more battery I appreciate it, please. Thank you. Thanks Rick. So working across the MCA above and below it, just finding the neck. Rick, for some reason, this one is not catching all the way. And then we'll go ahead and put a clip, you can see there two... Thank you. Two enter anterior corral arteries there, very interesting. We went ahead and put a clip around the MCA and just worked through the very small corridor making sure that small vessel is not compromised. Appears to be intact. I use it attracted just very temporarily during this operation, less than probably just a minute or two, so I can hold the brain as a third hand. You can see how the fluorescence helps nicely in terms of in a deep view, all the peripheral vessels are excluded and the aneurysm, I'm sorry, the peripheral vessels are patent and the aneurysm is excluded . Labrador atherosclerosis, good view of pyyton seal, both vessels and their results are satisfactory. Here's the postoperative angiogram demonstrating complete exclusion of the aneurysm itself. Let's go ahead and talk about endoscopic transnasal resection of craniopharyngioma. I do believe this fact that craniopharyngiomata are essentially gonna be, most of them, not all removed through the endoscopic approach, just like pituitary tumors, essentially. We've moderate size craniopharyngioma floor of the cellar, and the dura is open and very, very small opening, more than adequate here. Very faint still I think Rick, this one, I apologize. Thanks for it. So I'll go ahead. As you open, you see a very small opening, all you see is tumor, but you have to be a little bit patient and remove and debulk and as you de-bulk here. Thank you. Go ahead Gheto, thank you. You'll go ahead and remove tumor. pituitary stock comes for you now we're using a 30 degree endoscope and we'll be able to see the pituitary stock really amazing view. We were able to dissect the tumor, now we see the chronic, the superior hypophyseal branch carefully dissect using microsurgery and be able to obviously preserve all the vessels to sub cosmetic area. Now where I think we're using still 30 degrees, we'll go ahead and use micro scissors to dissect the tumor from the underneath aspect of the Caesium. I personally very much enjoy endoscopic surgery. Here you can see underneath the caesium this patient has some visual deficits before surgery. So the tumor was recognized, continue to work on caesium, obviously this view is in no way possible transcranial lead. Make sure all the perforating vessels are intact. I believe right now I'm using a 45 degree endoscope John ting is, and the skull are rhinologist. You really can get amazing view of the posterior pole of the tumor. Again, not dissecting the tumor from the optic radiations from the right side, you see this stock is completely intact over the right aspect of the operative cavity. We'll go ahead and disconnect the last attachment of the tumor. Here's the part of tumor that is disconnected completely. Again, we're not pulling on a thing blindly, after the capsule is completely and micro surgically isolated. And these patients typically go home a day or two later vision, significantly improve, you can see again to their stock, completely intact, no die after surgery. And I truly, am a big believer and enthusiastic when it comes down again to pituitary stock completely intact after surgery. I think through the transparent approach, this view would be extremely limited and the optic nerve would place the tumor outside that surgeon would find himself or herself limited due to the presence of the optic nerve. Here's the gasket technique, the risk of CSF is extremely small using this method, again, we only remove a small piece of opening and that's more than adequate. There's a septal flap go store resection, no radiation. The visual decline now disappeared and this patient did extremely well. I believe my last case is a large pontoon cavernous malformation using the telovelar approach. 32 year old female from two pontine hemorrhages, large lesion came very close to the area of the floor of the fourth ventricle. I operate in the latter position because I love to sit during microsurgery and have more steady hands if possible, shoulders move out of the way. Telovelar approach a great contribution of Dr. Rouen. God bless his soul. And again, mobilization of the tonsils finding the floor of the fourth ventricle mapping the floor, making sure the facial celiclus is protected. You can see that the Vellum is being quite isolated and cut. Here's the mapping part. You can see the floor is relatively swollen because of the presence of hematoma. As the facial nerve is excluded in this case, it was located most superiorly here, we'll go and make it a various small incision. First step would involve evacuation of the hematoma, the compression of the lesion. In this case, not to have the brain stem gets sucked into the brain, stem up place a piece of cotton and let it stick. And this way I can move the walls without necessarily having the brainstem gets sucked into my suction and gets more injured, very small opening. Now the feeders to the malformation, the cabinet smell permission are disconnected and next, the malformation would be carefully dissected from the gliadin margin of the brain stem, but obviously for brain stem calves mouse, we leave the gliadin margin behind, the malformation is delivered in a very gradual fashion. Obviously, if the floor was relatively intact, no matter how thin of it, sure, you can also consider coming through the cerebral pontine angle and just between the seventh and the fifth cranial nerves, just to be able to protect the floor of the fourth as much as possible. And this was a larger piece of the tumor that was, will be eventually delivered through this small opening very large cavernoma as you can see here, the resection cavity is very carefully inspected to make sure these white strands that are part of the tumor removed here as the developmental venous abnormality, that should be protected if at all possible, here's our final operative corridor. And this patient's weakness before surgery is significantly improved. And here's the post-operative MRI. I believe that's my last case. Thanks very much Dr. Gardner Paul. Thank you.

- Hi, thank you. So, so this next case, largely because it's partly endoscopic is real quickly a young man who presented essentially looked like apoplexy so sudden onset severe headache and vision loss, but had this multiloculated mass. And so he was on the, or schedule. I said, let's get an angiogram. And unfortunately he has bilateral ophthalmic artery aneurysms, which are partially thrombosis. Now the difficulty is given the size of it, it's difficult to get distal control with an endonasal approach. So here we're doing a right-sided craniotomy and doing a resecting the climate in this side. And here you can see the neck of the aneurysm, I'm sorry, left sided, here you can see the neck of the aneurysm coming up under the optic canal. So now because they're bilateral ophthalmic artery aneurysms, and I can't really see the proximal neck well, we did an endonasal approach, here you can see this is our proximal control on that left carotid artery by exposing the cavernous carotid. And we come down to the pier clival segment, which is the proximal cavernous segment of the carotid artery. So that gives us us proximal control on that side. And then we have the contralateral and ophthalmic artery aneurysm, which is also partially thrombost. And so we'll expose that carotid and then do the super cellar approach. You see this a very wide approach to removing all the bone, all the way from one optical carotid recess, which is the optic strut to the other. And so because we moved the clinoid on the left side, we can see all the way through the optic strut in this patient. So now for my proximal control, which is really the first step, I'll open the medial cavernous sinus here, parasellar medial cavernous sinus. This is a little hook blade by Mizuho, and you just see some, a little bit of venous bleeding around the cavernous crowded, which can be packed off with some surge of foam. And now this gives me a very nice proximal control, proximal to the dural rings as it come around the optic strut. Now opening across the diaphragms and into the super cellar space, here, we start to see the distal, we see the optic nerve come into view, and then we see the neck of the aneurysm. So the one that big advantage of this is with this approach. I don't have to manipulate that optic nerve at all. I'm able to dissect the distal neck of the aneurysm there off of the optic. I don't have to lift up the optic nerve to see the neck of the aneurysm and here's the proximal neck being dissected. So now I have with an endonasal corridor, I've a very direct access in line, here you can see my partner, Dr. Jencuets working trans cranially here through the optic strut and the clinoid. And I have a very direct view and a really direct shot in line with a pair of chancroidal carotid artery. There I think he's just trying to distract me. And here I'm placing the clip across the proximal and the distal neck of the aneurysm again not touching this optic, again, the patient presenting with vision loss, I wanna minimize optic manipulation as much as possible. Here's the view simultaneously from below. You can see he's making sure that my clip lines up perfectly, but you can see with the trans nasal corridor, my clip is perfectly in line through the ipsilateral nostril with the ipsilateral pair of carotid artery. So that's the clip going into place. I can then do an aneurysm morphy to decompress the chasm You can see the chasm starting to come in view over top of this very large left side of the aneurysm. And then here's the right side up thalamic aneurysm. I think it would be very difficult or impossible to see this aneurysm or see the neck of the aneurysm through a transcranial approach. And so now I'm getting the proximal control on the right side, opening that medial cavernous sinus in the same way, dissecting the distal dural ring on the right side. And now I can start to see this aneurysm come into view on this side as well. Here's the distal neck of the aneurysm next to the between the chasm pair of carotid. You can see the ophthalmic actually coming off right here immediately and going into the optic canal. And so there's my proximal and distal neck. And I can again place a clip, in this case, I used a curve clip because the aneurysm, when a little bit superiorly on this side, rather than going directly immediately. So now really decompress the chasm thoroughly. One of the challenges with this you can see the clips stick into the sphenoid sinus a little bit so you do have to pack some fat around them so I do a durgin inlay and then some fat around it followed by a nasal septal flat for the reconstruction. But CSF leak is a concern with this approach obviously. So you can see a little bit of clips out and you want to make the fat a really protects the clip from the nasal septal flap. So here's the flat going up, very large flap fills the entire sphenoid and here you get a glimpse of the fat which is filling and protecting the clips. And here you can see the light with the ophthalmic coming off and the left with complete clipping actually got very nice recovery of all of his function. This is a very similar case of a approach. Again, this will be in 3D to what Dr. Caldwell showed with a lot of orbitotomy. And this is a 73 old man with a Multiply recurrent post radiation tumor. He's got some vision loss, but what he really cares about is he's got severe trigeminal neuropathy from this. He's got partial ophthalmoplegia, and he doesn't really use his vision in his left eye. Nevertheless, these are sort of what we consider options for relief of his trigeminal symptoms. And we plan for a lateral orbitotomy. One of the concerns with this is the frontalis comes very close, as opposed to lifting the frontalis anteriorly. You actually dissect medial to the frontalis and the frontalis goes lateral. So here we're plotting out the frontalis that allows us to you can directly stimulate it, know exactly where your frontalis is. This is obviously a cadaver model, a little bit different than we extend directly from the lateral canthus to take advantage of the eyeopening to gain access to the medial orbit. But it's really an identical approach that you saw earlier that Dr. Caldwell is obviously presented and published in the past. And here's a wide lateral orbitotomy and that gives us direct access onto the medial sphenoid wing. The temporalis muscle is pulled laterally here the orbit has a retractor medially, and I'm dissecting right down onto the cavernous sinus in a inter dural fashion between V2 and V1. You see going into superior orbital fissure, you have to be careful about your retraction on the orbit and let it up every 10 minutes or so. But this gives me a very nice corridor right here in between V1 and V2 here on doppler ring, just medial to Merkel's cave to doppler the carotid artery, so I've defined that. And now inferiorly working deep to V2. Unfortunately, this tumor had displaced a lot of the trigeminal laterally, so I'm forced to work around the nerve and here I'm starting to see some of the fibers of the casserole ganglion so I've defined the posterior aspect of it. And now I can chase once I've protected that with a patty, I can now chase the rest of the tumor into the posterior fossa to make sure I completely decompressed the tumor from the trigeminal nerve. So my main goal here is while I do get some decompression of the cavernous sinus, my main goal here is completely decompressed the Merkel's cave and the trigeminal nerve as extends into the posterior fossa. This is delivering that last piece from the posterior fossa. The tumor has dumbbells in the posterior fossa so I can go through the mouth of Merkel's cave like this, and we'll get a view here at the end onto the ponds through this approach. So here we can see the view between V1 and V2, following the concern ganglion back through the mouth of Merkel's cave into the posterior fossa. And now I'm just trying to clean up some of the edges, get maximal decompression resection that I can, resecting some tumor again from the underside of V2 and out toward cavernous sinus. And here you can see the preop and postop and enabled to resect everything lateral. We left the medial cavernous sinus component. The tumor has been relatively welcome trolled except for that lateral portion and it wasn't atypical meningoma. And he did have complete relief of his trigeminal pain. This next case is an example of using an endoscope to really assist a more traditional approach and extended retro mastoid combined with super cellar cerebellar approach. This is a 60 year old man who had a prior resection of this tumor two previous times, and was left with a transection of his fourth nerve, which of course makes our lives sometimes a little bit easier. He's otherwise neurologically intact. He does have a difficulty with tandem gait and walking largely due to brainstem compression but has this cranial nerve palsy. You can see this extensive pretty obvious epidermoid extending all the way up to the atrium of the occipital of the lateral ventricle. You can see involvement, another labial down-low of the IC, and then extending again across the tentorium, both super cerebellar, and then back towards the tent, back towards the ventricle rather. I'd like to thank a doctor's Zwagerman for all this help both with the cases as well as with putting these videos together. So this is a left sided retro mastoid and super cerebellar approach. You can see it's, you know, a lot of scar here redo surgery. And so here, I'm just dissecting the scar over the epidermoid between the tentorium above and here, I'm starting to see, I see lower cranial nerves dissecting the arachnoid free between nine, ten, and seven, and now working superiorly, We start to see the trigeminal nerve come into view. So there's a lot of tumor really involving the ponds and the trigeminal nerve. And I have a very direct view with the microscope for all this portion, both onto the ponds that the trigeminal route as well extending super cerebellar towards the midbrain. Here's the really the super cerebella route looking up towards the midbrain. And we can start to see a little bit of ankus come into view, I can see the PCA coming around the corner. There's a third nerve in the distance, but really you can see the issue here is with a microscope. I really start to lose visualization. So we'll bring in a zero degree endoscope under direct visualization, I'll cut part of the tentorium to all the way to the lateral aspect of this tumor. I can now, again, I just, because I'm using endoscope, doesn't change my surgical technique. I might use slightly different instruments, but still using microsurgical technique to dissect this SCA branch. And again, piecemeal resection of the tumor. But my big concern is I have PCA and SCA perforators. You can see these PCA perforators which are really intercalated in the tumor which is now scarred in. But I know there's a very large loculation of tumor here going up towards the ventricle. So kind of patiently working around these perforators and then since again, I can't get a good view of that PCA, bring in an angle to endoscope, and with this I really start to get a much better view of the PCA, so I can see the PCA coming around the corner, I can do a sharp dissection now, now that I can actually see the artery better, I think I can do a much cleaner dissection. The last thing you wanna do is reach around the corner when you know there's a vessel there and pull on this tumor because you'll have volts the PCA for sure, and then have a catastrophe. So now I'm working through the pocket, this is the midbrain you're looking at directly. And then we're working up just above the PCA out towards, out laterally towards the temporal lobe and the atrium of the ventricle. Again, we're working through the cut tentorium. You can expose the entire underside of the posterior temporal lobe by cutting the tentorium widely. And then I'm just using an angled grasper here just to basically peel tumor off of the mesial posterior temporal lobe. I know this area, it seems relatively clear, I don't think there are any PCA perforators in this area. I can see very clearly when I'm peeling there's a little bit of tumor left out most laterally toward the underside of the temporal lobe, I have a very hard time seeing and so therefore I don't wanna resect very aggressively and you can see where it's really thin to the temporal lobe out towards the atrium, a small amount of residual. This is just the area, I just can't quite reach from this approach. He had some very mild aseptic meningitis but really did quite well. I think we have one more case, but I think in the interest of time, Aaron, I think we'll probably skip that and go ahead to next speaker.

- Thank you. Just want to start emphasizing Dr. Rottens words on the importance of surgical anatomy, the importance to do accurate gentle, safe surgery. So please Gheto the go ahead. We're gonna do, first case is gonna be, the first case is gonna be penal Canaveral internal meningoma. So this is a case where we're going to have to use a lot of the surgical anatomy we actually learned in the lab. And then it is a tumor involves multiple compartments inside the cabin or centers we're going to left on task, but did you compare with anatomy involves middle fossa, but also post your fossa towards a Merkel's cave. So we need to understand the layers of the dura or the middle fossa trigeminal nerve. I need to brunch this, the different triangles of the middle fossa including medial antero lateral and colossal strangle. Because when I expose all these doing first the Hakuba, dissection of the dura, the middle fossa, then we'll do the lengths technique to cut through the roof of the cavernous sinus. So we can mobilize the dura and finally, we'll do the, the Colossus technique on doing the Pecos apex and getting to medical cave. So for a tumor like these, we want to have good space. We do our normally two psychometric craniotomy, two pieces. Do you see the catacombs, the body of this eyegoma? The nice thing about doing a two pieces technique is you can save a lot of the roof of the orbit. You see the osteotomy is really posted, are there. So when we replace this piece, although you say intact, and now we're going to start doing our extradural approach. The first step is fundamentally where we tell band qualities and transecting, it exposes the anterior climate, which is clearly hypostatic here. And this is tumor in the dura. We start pilling exposing the super wheedle fissure. Then the lateral wall, the carvenal sinus going back to us V2 and V3 will be in this area. And we peel completely these meningeal due to the temporal lobe. And I will start drawing out the hypersonic bone that is causing the proptosis on this patient. This is V2 and escalatornice. We drill the antero lateral triangle. This is V3 here, and this is the phenomena spinosum I like to drill around the phenomena spinosum so I can coagulate the already more proximal and transected, and then going from posterior to anterior exposing the Peter's apex. And now I'm going to try to find ESPN in this area, running longitudinally, I'm going under V3, which is here. So this is our ESPN. Now all the Peters Epic's been exposed, it's very important to mobilize V3 all the way on terriers. We can get the most anterior aspect of the Peter's bone, in our drilling. And the goal here is to expose enough through the fossal so we can get below the tumor and find five. And this recent dual opening release in CSF, we want to do a kind of ectomy. Before we go into drill, we start by unroofing the optic canal, continuously irrigation, exhale technique. And then we're going to drill below the optic nerve to find the optic strata detach the clinoid from the optic stride, this is the clodial in the conoidal space. This is the remaining piece of the optic strata. And this is the client which actually was formula small ring with a middle client, right? As you can see right here, these are space. And we have all the nerve exposed V2, V1, V3, and this is the extra external portion of the operation. Now we need to go internal for which we start opening the assistance. This is be to the stock. We can see two more here by corroded, and it's important to carefully open the Sylvian fissure also a bit because we need to mobilize the temporal lobe and this Sylvian fissure opening is going to help us, you know, mobilize a temper a lot more effectively. And here we go all the way to the carotid bifurcation and their next step is gonna be finding the oculomotor nerve find in three, opening the rac around three, and that I don't have recess of the interpreter in color system here. And we want to follow three all the way back to its origin from the brainstem, you know, for, from his, from his exit zone in the brainstem here. And then we keep opening the racking rates we can see visor, bifurcation, PC, and STA. This is a brainstorm right here. So now we're going to start finally getting after tumor, after all these wide exposure, extra blood, an intradural, and this is the tumor on the roof of the Cardinal sinus. We can see three at this level, and now we need to do this important castroid here that Dr. Lang describe and is discovered in ballsy petal clynal ligament, and is gonna allow us to mobilize now these hold due to the temporal lobe from superior to inferior along the tent. We are seeing the tumor that is growing out of the tent, and now we transect all the meningeal dura that has tumor on it. Now our next step is going below that in tentorium. So we're cutting through the tent, we find five, the posterial the five, this is cutting the dual ring around Merkel's cave and then the tumor within Meckle's cave is being removed. Our goal now is to transect this tentorium, remove the tumor that is in the post-it of fossa. And we can see here, the PCA, I'm sorry, the SCA and then we are transecting the tentorium here and you can see that it's a brunch here, which is a variation, this is the tentorial already of the SCA, and this is fourth. And as we moved the microscope, you know, the blood is being evolved from the artery, there is a nice hole in the SCA right now that we can not coagulate. So we just put a small micro clip to control that easily and with no problem, that's fourth. And we start getting towards the limit of our resection. We are looking back there was it an we cut extensively the fourth nerve from going back to the quarters immune system. And these are the end of the resection where we move all the tumor except the one that remained within the carbonyl sinus. And our goal would be to do radiosurgery for that remaining portion. You can see the early post-op in these patients, you got worse and in double vision, right after surgery, but she started recovering a few weeks later. And actually at three months, you can see here in the gamma knife. Solid with a full recovery, or almost completely covered her double vision. So these next next case now is interesting case of a patient who presents with two of many angiomas and both of them are symptomatic. The suprasellar one is causing right optic neuropathy. The pitoclival one is causing numbness. And she is, you know, asking for what advice and we, you know, I thought we could do these both from an endonasal approach using techniques that we have described on. Working around the optic canal and working around the petalclavel postal clinoid. So we're not of the anatomy, the approaches, as you know, endonasal approach by an aerial, we exposed up to the limits of this sphenoid. It is key to understand the anatomy of the optic analogy go endonasal so we can open it effectively. And now we're going to do a Supercell or an infrastructural approach that we are going to combine with a trans carbon techniques. So we can expose the poster climate inferior hypophyseal artery, we'll remove both. And then we'll open these lateral recess of the interpreter in color system. We will see three, we'll see the PCA and the SCA. So we have done the approach. We have reset part of the tumor. We're doing the supraciliary space resection of this tumor, which is multilobular. So you need to be very careful with your technique at here with two microsurgical principles of salve dissection, and careful technique to dissect the tumor from the vessels. This is the AECOM right here, and this is one eight to these, the contralateral, a two, there is an ankle of team are going towards the interhemispheric fissure. And then this is a frontal orbital brunch that attaches to the tumor and tumor is actually having some soup here, invasion right here. And this cut here is key, the cut on the dural, the optic canal. This is going to free the tumor so we can mobilize it. We're using here these forests and technique to look at the vascularization of the optic nerve. And after doing this cut, I can remove this tumor from within the optic canal effectively, you can see the atomic artery nicely exposed, and they can remove the tumor along with a dura that distal ring, an optical dura that's that's been involved. So we finished the first tumor, and now we go trans cabinets. We opened the the andrualdecabinal sinose, mobilized the medial wall. We can see the inferior hypophyseal already before we have also, we just coagulated and transect the artery. And that's gonna allow me to now expose the postal clynal that is behind. And these are very hypostatic postural client reader. So I to do an extended mobilization of the pituitary cut into the proximal and the distal drawing. So I can now get all the way to the top of the poster of clinoid drilling it. And finally we'll be able to detach it and then mobilize it. And you see this as the quite prominent postrial clynoit hypostatic and behind this kind of is where most of the tumor sits. So these approach will put us right on the right on target for studying tumor de-bulking. I know I'm going to find three, and this is the oculomotor nerve and PCA superiorly and SCA in fairly does the anatomy we described before. And the struggle here is the lateral attachment of the tumor, but Potter is the most dangerous, of course, the vascular already. And it performed in branches coming off the outer and they already so it's, but you have perfect visualization of this area. You can do nice, careful dissection to peel the tumor off the vascular. And finally resect the majority of these tumor. This is the extension laterally, and this is the resection cavity after posted a photo. And suprasellar andrea fossa resections. And our main concern is reconstruction. We use multi-layer technique. This is a fast, a lot of fat graft and the septal flap covering the whole defect, it perfuses nicely. As you got to see how that very nicely corporated with resection of both tumors, her symptoms got better, both the visual symptoms and the trigeminal numbness. Next case is you will be also an endonasal case. This patient also has two tumors. And, you know, one is this one that is a very ventrally located from a magnum meningoma. So you got an adjacent tumor that I believe is asymptomatic. So we just to go to these endonasal because the tumor is completely within the vertebral arteries. And with techniques we described on doing a middle condylotomy these a very nice case for an endonasal approach. So that's what we'll do. We'll do an lower transcaval approach working through the nasal fairings in between the station tubes. Key to drill these maxillary crest, flood it and then through the nasal fairings, we expose the lower climbers all the way down to the foramen magnum and see arch as you see right here. We use this formal as a landmark to describe or middle condylotomy the extent of it. And this is just about 20% as we investigated in the lab of the amount of the condyle you need to resect it as a medial 20% of the canal gives you access to the vertebral. Remember hypoglossal nerves always run down side to the vertebral artery.

- From the lower area.. Can you just put the volume, adjusts the volume of the video. So going through the nasal foregial fassial is a bit tedious. You need to either mobilize it down a complete dissect, transect these mussels, but finally you get into the form of magnet right here. This is a C1, and there is a nice group in this area that correlates with the level of the hypoglossal canal, the supracondylar groove, and again, from a magnum, this is the condyle, this is C1 mass. This is the C1, anterior arch same anatomy. As we see in the laboratory, and now we just continue our drilling through the inferior clivus all the way down to the forearm magnum. And now the most critical part is doing this middle condylotomy, which for these, this bunker is very useful because it allows you to do site the drilling of this middle conduct, and you see how the dura stores curving around. And this is the key aspect. You want to see that dura that is now going around the lateral wall of the front and Magnum that tells you that you have enough exposure now to do the tumor resection. So when I do a very white dural open-ended, since we have all these windows open like a book mill and and open superiorly and also inferiorally because that's gonna allow also the pulsations of the brainstem to assist with the dissection of the tumor, you see that dura is widely open, and we find our rac plain after some de-bulking, and we'll protect these arachnid plain and the medulla with coronoid patties during our dissection, detaching the tumor from the dura. And now we need to find vertebral arteries on each side. We know the hypoglossal nerves are going to travel behind the vertebralis. So this is one vertebral on one side is the contralateral vertebral. So we try to detach the tumor. Very important always to do large de-bulking of the tumor is built to take the two in small pieces and in that large single piece, and then these extradural dissection, what extra story meant with all the ragged bonds, the tumor is now very easy to mobilize, and this is one vertical already here. You can see through this of 12 behind, and then last arachnid attachments. You can see this have roots of 12 right here. And the last portion of the tumor being removed. You see the beauties we are working between both vertebral arteries, the hypoglossal nerves in these ventral approach. We can resect the lower attachment of the tumor, making sure that even the dura has been remove and exploring for any receivable that's 12 going to the hypoglossal canal behind the vert and the resection after, after resection the view. Now the challenge is always, the challenge is always reconstruction. So we came up with multi-layer technique for this is very important layer fassal under and then using fat grafts and extended flat double cover. The whole effect are key for, for avoiding CSF leak in this area. And this patient is still has that small tumor laterally that is asymptomatic and will address in the future if needed, but you see the full resection of the tumor, we're going from the front events, a lot trajectory, You can see here, the extent of the medial condylotomy as we go anterior, and we compare them with that parallel approach. Could you go to the very last one? So this case is a complete different cases, a young woman with this expanse frontal orbital mass, and I put this case just to emphasize the importance of supra total resection when possible in tumors in this population. And you need to base it on atomic alarms. In this case, I'll factor it, try again, the crowded nucleus or the ventral is three landmarks. And it's important that we keep anatomical principles to do these tumors. We hear a lot about mapping, but there is no point in doing mapping. In this case, you need to use anatomical mapping to do a good resection. We do fiber tracking just to understand a bit of the relationship the tracks will do. I'm not worried about any eloquent fiber track in this particular patient. And the first step is opening the assistance. I know that the old factory track is going to be a key landmark for this resection. Another long one is going to be the Sylvian fissure, because there were section goes from Sylvian fissure to the inter hemisphere fissure. So just open it to a little bit to know what it is. And then this is our resection area. This is cuter where the tumor is, can be identified the same in this frontal orbital GRI. So we design a CT discectomy and now we're going to do all sort of in block removal of the majority of these area, this frontal orbital region. This is interhemispheric fissure and we try to find the arachnoid to super arachnoidal dissection CPL. We tried to find out plain of white matter that is deep enough. This is again interhemispheric fissure. And now we're going to go from the midline, posted your superior margins here, and then laterally. We can see the corolla we use as a reference is your factory track. We can continue peeling the factory track. Remember our postrial limit is the olfactory trigon and tubercle and that's when you see the factory track becoming a triangle is where, you know, the anterior perforate, the substance is going to start, right? Oh, still, that's what I want to stop, but I want to endure any of the perforators going through the periphery, the substance. And this is the removal of the majority of these frontal orbital area. And now you can follow my landmarks, the optic chasm, back to the laminate terminologies. I can resect all these areas of brain here. We can see the A1 segment. I see this is still from the orbital. I'm not yet into the ventral striatum. You can see some of the periphery in branches. You saw that we are wearing the factory triangle already. This is now going to Sylvian fissure to complete our lateral extent of the resection and these all the way back this gray model here is the vertebral more carried nucleus, this is the frontal horn. Now I have my deep landmark. I can resect some of the white matter around and then complete the supra total resection of this tumor that did is some early evidence that these super total resection might reduce or increase the time until malignant transformation of these tumors. In fact this patient came up as an anaplastic astrocytoma and grade three, but she has no deficits. And this is her right after surgery two weeks after surgery actually in the clinic. Thank you.

- [Aaron] To everyone, including our dear faculty, and you guys have a great evening.

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