I'd like to welcome everyone once more to yet another episode of the Front Row Series, this new educational series from the AANS NeuroU, the new educational website of the AANS. Today's webinar will be focusing on skull-based surgery. Again, the Front Row Series is a series that features renowned experts from around the world. The topics include skull-based cerebrovascular tumor radiosurgery and more. Participants will have access to both the live and the archived events for CME. And again, for the first time, participants can also submit cases for expert discussion. Today's experts really need no introduction. We have Dr. Danny Provodello. Dr. Provodello has been at the forefront of minimally invasive brain surgery, particularly endoscopic surgery. He's an alma mater here. One of these alma maters is here at the University of Pittsburgh. And I kind of consider him kind of a mentor from afar. I've learned a lot from his presentations, and every time I hear him speak, I learn something. And we also have Dr. Gabriel Zeta. Dr. Zeta is one of the rising stars. He's already a in the field of brain tumor surgery and skull-based surgery. And he leads a very strong research effort, but also a fantastic clinical effort as well. So I'm looking forward to both the discussions today. Again, for the participants, please put your questions in the Q&A, and then we'll get to them a little bit later. And then we'll have the time to go over some cases and see what our experts think. I guess we'll start with Gabe. All right. Welcome you both again. So Gabe, take it away. Share your screen. Sounds good. Thank you so much, George. And thanks to the AANS for having Dr. Prevodello and I here. So for about half of the hour here, I'm going to talk mostly about keyhole approaches and some other minimally invasive endoscopic approaches, mostly to the skull base. And then Dr. Prevodello will talk about endonasal versus lateral approaches. Here are my disclosures. So I'm going to kind of talk about the current catalog of minimally invasive and endoscopic surgery to the skull base, highlight some of the benefits that endoscopic and keyhole approaches provide, and then review some of the most common approaches that can facilitate really 360-degree access to the skull base, whether it's anterior, middle, lateral. And of course, there's been a major evolution with the endoscope and minimally invasive surgery that is still underway. And it's very fun to be a part of this in any way whatsoever. The angled endoscope in particular has a very defined role in minimally invasive surgery, even going back over 40 years now. Some of my older colleagues from USC here described some of the first applications of the angled endoscope, even for endonasal surgery and vascular surgery. And then we're now at a quarter of a century since the first pure fully endoscopic approaches to the pituitary and skull base. And of course, we get beautiful views after removal of a craniopharyngioma, for instance, where you see these amazing views of the basilar apex and brainstem and mammillary bodies, and really allows you to see in anatomical compartments that you couldn't see otherwise. And of course, how far we've come, this is some of the earliest video of endonasal or transphenoidal surgery with an endoscope over half a century ago, and how far we come with optics and our technology. It's really amazing to be a part of this process. So minimally invasive surgery, of course, has an important role throughout surgery and neurosurgery is no exception. And of course, there's endonasal approaches, which won't be the focus of my talk, but of course, we know that keyhole approaches and less bone removal, et cetera, can really afford better outcomes for patients and faster recovery rates. And we're so limited by our optical technology. And in the last several years, we've seen really a variety of different optics, whether it's the microscope, endoscope, or in later years, the exoscope, there's a questionable evolution, which I'll come back to. But I would say it's really more important to use all of these interchangeably to achieve whatever kind of visualization or optics you need. And so really with small natural corridors and keyholes, we can access the skull base and even subcortical and intraventricular regions through minimal access points. So I'll be reviewing some of these, but really focusing on the skull base. In terms of neuroendoscopy, I have pretty much an adult practice. I don't do a lot of pediatrics. So we do some intraventricular neuroendoscopy, obviously through small burr holes. This is mostly ETVs and biopsies, occasional other treatments such as septum pellucidotomies. I no longer do colloid cyst surgery with a neuroendoscope in a CSF medium. Of course, endoscopic endonasal approaches make up a large majority of what we do with natural corridor endoscopic surgery. And then I'll be focusing today on keyhole craniotomies, whether they're endoscopic purely or endoscopic assisted. And then finally, I think the latest in minimal access surgery is port-based surgery through very small craniotomies, which I do think is very important. I'll just be showing one or two examples of that. And just in terms of caseload, over about a decade, this has been our service development, mostly endonasal endoscopic approaches, but really a selected use of a lot of these other ones, but well over a thousand cases now in our minimally invasive catalog. So endonasal approaches I won't be focusing on. Suffice to say that we can access the entire midline skull base and Dr. Prevodella will be talking about lateral skull base surgery a lot more, whether they're direct or extended procedures. And of course we treat a lot of pituitary tumors, et cetera, with this. And this isn't the focus of what I'm doing, but of course we can access anything in the cella, even larger pituitary tumors we can treat with direct procedures and they rarely need extended approaches. Then we have the use of the angled endoscope, as I mentioned, to look into the supercellar region or cavernous sinuses, and that can afford additional tumor resection without the need for an extended approach in some cases. But really the pathology can sometimes dictate whether something lends itself to an endonasal approach or requires a craniotomy, whether it's a traditional open craniotomy or a minimally invasive craniotomy. And these are some of the factors that we look at. Firm tumor consistency is an interesting one that I think requires more research in an effort to try to predict which are the more firm tumors. And so for pituitary tumors and meningiomas, we like to score these and we're obviously working on different neuroimaging techniques to try to predict this. But in pituitary tumors, we know that more firm tumors need to be resected with extra capsular resection and this can also limit the extent of resection, especially of the supercellar regions. So we have quite a catalog of endoscopic skull base approaches. For extended approaches, we require different instrumentation and a much different setup. And so you want to make sure that you have all of this ready before doing these approaches. And then it becomes a decision-making process of endonasal versus open, keyhole or traditional craniotomy for tumor resection. And I'll be focusing on the latter for this, but it's important to have all of this in your armamentarium when you're doing skull base surgery to make sure you can approach things from above or below and really develop that clinical acumen. So for a lot of anterior skull base tumors, obviously there's the transtuberculum and transplanum techniques. And these really lend themselves for craniofringiomas, which are mostly done this way, I would say, at most academic centers, including our shop. For meningiomas, it's a different story. And I think myself included, a lot of surgeons are 50-50 about that. It's always important to understand the neurosurgical anatomy from above and below, whether it's the nervous anatomy or the anatomy of the carotid artery, and of course, in relationship to the bony anatomy. And to understand the course of the carotid artery, whether you're seeing it from an open craniotomy or an endonasal approach or a minimally invasive keyhole approach, we have to be able to understand this anatomy from all directions. So for craniofringiomas, they really lend themselves to endonasal resection. And we only really do craniotomies when someone has had an extended approach from below, or we require a more virgin approach, or there's another contraindication. But most of these we can do safely through an endonasal approach now. For meningiomas, it really depends on the extent of tumor growth and invasion. Especially lateral extension. So well-suited meningiomas can definitely be an endonasal approach. This was a very well-suited tuberculum cell meningioma for an endonasal approach. And so just for those of you, this is what the workflow looks like. We've done a trans-tuberculum approach and are decompressing the tumor and doing sharp dissection away from the optic nerves, and you can get great visual outcomes doing the operation this way. So it's important to know how to do these procedures. What I'm going to focus on mostly today is our keyhole approaches, in particular the eyebrow or superorbital approach. And this can be done with a variety of incisions, whether it's a true eyebrow incision or an eyelid incision, or even sometimes a hairline incision, a standard frontotemporal hairline incision with just a small superorbital craniotomy can be done as well. Just for the trainees, one of our major workhorse approaches is the tereonal approach, and you can do this with a standard or a mini-tereonal approach, but it's really a very lateral to medial approach. And of course you can add an OZ or a modified OZ when needed, and that will help you look superiorly and down into the middle fossa. But looking back towards the basilar cistern and basilar apex or working between the optic nerves can be difficult, and so sometimes a more subfrontal approach, especially with a superorbital craniotomy, can be very helpful and give you a different trajectory that's more similar to an OZ. So I'm a huge fan of the superorbital approach. Sometimes you're limited by the morphology of the frontal sinuses, but no matter how you do your incision, a superorbital approach gives you a more midline anterior to posterior trajectory, much more similar to an endonasal approach than a classic tereonal approach. So there are many indications for a superorbital keyhole craniotomy. This was of course developed for vascular lesions, especially by Pernetsky's group for a variety of aneurysms, particularly ACOM aneurysms, but of course is widely used for anterior skull-based tumors, in particular tumors of the olfactory groove and planum sphenoidale, and then well-suited tuberculum cell meningiomas and clinoidal meningiomas. I will use this for recurrent craniopharyngiomas where we have extensively used an endonasal approach. This is also a great rescue operation or salvage operation for craniopharyngiomas, and then for frontal sinus pathology and other orbital roof tumors can also be very useful, can also be very useful for anterior third ventricular tumors by going through the lamina terminalis above the optic chiasm. So the steps of this, we usually just do a midline eyebrow incision. Other people will do an eyelid incision, and they're both, they can both be very useful for this. You want to watch out for the superorbital nerve more medially, and the frontalis branch of the seventh nerve laterally, also very important. I do not remove the orbital rim for this, and I also do not prepare a pericranial flap. I just take a lot of caution to avoid the frontal sinus, and I'll use navigation to avoid that as well. Once we've done our small craniotomy, after doing a McCarty burr hole at the anatomical keyhole, we'll do about a three by two centimeter superorbital bone flap, and then we'll drill down the undersurface of the orbital rim, but not remove the orbital rim completely, and then work our way under the gyrus rectus to whatever the pathology is. So here's an example of a mostly planum sphenoid alley and tuberculum meningioma. We're on the right side. We make a midline eyebrow incision, and I like to use these low profile lone star retractors. We then do a McCarty burr hole, and after drilling down the undersurface of the orbital rim, we open the dura and flap it over the orbital rim. Now we're debulking this tumor. We're trying to devascularize it by taking off the skull base, and this is sped up a little, but two-handed dissection away from the chiasm, and then the left optic nerve here reaching cross-core. Careful dissection away from the carotid arteries, and then tumor removal and bony replating, and then for a closure, we do a multi-layer closure with a subcuticular stitch and dermabond at the end. In a young woman who does not want an eyebrow incision, we'll do a standard hairline incision, which heals better oftentimes in women with thin eyebrows, and then we'll do the same very small superorbital craniotomy, and here's just another example. This one could have been approached endonasally as well. I did this one several years ago. What I like about the minimally invasive keyhole approach is that the hospital stay is usually about two days. You don't have to worry about a lumbar drain or any kind of sinonasal morbidity or CSF leak, and I think that a well-performed craniotomy can often be better than an extended endonasal approach and selected meningiomas. I don't think that's the same for craniopharyngiomas, but with careful selection of meningiomas, I think that the outcomes, especially hospital stay outcomes, may be better, and so just an example of the pre- and post-op imaging here. You can see preservation of the pituitary stock and gland and decompression of the chiasm, and her vision got much better. Just another few examples of lesions that we've treated with eyebrow approaches, a variety of meningiomas, and then this patient allowed permission to use his photo but tends to heal very well, especially when patients are challenged follicularly like I am. This is a nice way to have the scar heal and not have it be visible. Occasionally, with pituitary macroautonomas, which can almost always be resected endonasally, this happened to be a very firm one, and I could not get the superior component to descend safely, and we used a flap here, and so I was left with this residual tumor here. This was several years ago, probably would have done more of an extended approach now, but this was a young man in his 40s, and rather than radiate this component on the chiasm, we definitely wanted to resect this. You could go back through the nose for something like this, but we did an eyebrow operation, and you can see the resection there, and his vision was preserved here and has done well since then, so it can be a great salvage operation. Here's a planum sphenoidally meningioma, and of course, this can also be performed endonasally, but with selected use, an eyebrow craniotomy can be great for this. This was a one-night hospital stay, and I think I have sometimes a preference for doing these with craniotomies for that very reason. This was a patient with a craniofringioma operated on several years ago and radiated with recurrence. There was vision loss. It was pre-chiasmatic, which is very critical for craniofringiomas, and extended out laterally, and because it was radiated and adjacent to the carotid artery, this was a great tumor for an eyebrow, a superorbital approach, and we were able to completely resect this, and I felt like I had great control and visualization of the right carotid artery, and working between the optic nerves can also help with a tumor such as this one. Here was another patient in his 70s who presented with a rare arachnoid cyst of the cella and supercellar region. Occasionally, you'll see true arachnoid cysts here. I think a lot of people would approach this endonasally, and there would be nothing wrong with that, except these have a high risk of CSF leak rate and a need for reconstruction, so we did this with a full endoscopic eyebrow approach. He had a frontal sinus morphology that lent itself to this, and the goal here is just to fenestrate and decompress the cyst and send the anterior wall for biopsy. We preserved the arachnoid and vasculature on the optic nerves. This is about a one-hour operation and no need to worry about a CSF leak risk. He went home post-op day one with improved vision, and that was essentially our goal. He's in his 70s, and we had no recurrence over the last several years, and all you need to do is, of course, not resect the whole cyst, but open it and fenestrate it, and now you see a decompressed optic chiasm over the top of this. I think sometimes this is even favorable to an endonasal approach when there's no worry about a CSF leak risk. The eyebrow approach is a very powerful approach for anterior skull base pathology in terms of keyhole approaches. I want to talk a little about pineal region surgery and then a little bit about CP angle and posterior fossa surgery. For access to the pineal region, there's, of course, many different approaches. I'm going to focus on the super cerebellar infratentorial approach as one of the most commonly used ones. Of course, there's a very robust history of surgery in the sitting position for these tumors, and we no longer do that. We do these fully endoscopic without the microscope whatsoever, at least as far as our super cerebellar infratentorial surgery goes. It really lends itself to an endoscopic approach with minimal retraction once you've gotten the cerebellum to kind of fall away from the tentorium and you've sacrificed the necessary veins on your way in. This is also about a three centimeter cranny right below the torcula and we do this in concord position and without any more sitting position which can be ergonomically challenging for the surgeon as well. So this was a woman who presented with symptoms of normal pressure hydrocephalus. She had a pineal cytoma causing obstruction and so we're doing this fully endoscopically under the tentorium here. Here's the vein of Galen and we're sacrificing one of the superior cerebellar veins and now we're working around the capsule of the tumor, dissecting it away from the tectum and then gaining access to the posterior third ventricle. So we'll see a gush of CSF and we know we've decompressed her CSF pathways here. You can use two-handed micro dissection and then we're really looking into the third ventricle there. Here's the resection of the residual there and we know we've decompressed the CSF pathways and achieved at least intraoperative gross total resection which was confirmed on MRI and she had no need for CSF diversion or a drain and has not had a recurrence several years later. Here's another patient with a metastatic melanoma causing a Peronard syndrome. He had a hemorrhage into this tumor which is of course common for melanoma and this could have been treated with primary radiosurgery but he was symptomatic with a hemorrhagic lesion and so we thought this would be best suited with a resection rather than just radiosurgery. Same approach, we're now working around the melanoma tumor, dissecting it away from the habenula and the tectum and then gaining access to the posterior third ventricle and careful dissection from the tectum and he had post-operative radiosurgery even though it was a complete resection. Again, we're looking into the third ventricle afterwards, some surgery cell down at the bottom there and he went on to have a radiosurgery and no recurrence to date and gradual improvement of his Peronard syndrome. Again, we can do small craniotomies in the CP angle and posterior fossa and I'll just show you again where some of these endoscopic approaches can be very useful. One great example is epidermoid tumors which really lend themselves to an endoscopic resection so even when we start with a retrosigmoid craniotomy in a microscopic approach, careful dissection away from the cranial nerves and vessels, we hit a limit because of our ability to look around these anatomical corners so we'll put an angled endoscope in really with epidermoids because they can be curetted and suctioned out, you can work safely around anatomical corners to take additional tumor off the brainstem and cranial nerves even though you don't have to take the whole capsule if it's not safe to do so. Here's just another example of a 30-degree endoscope looking around corners and we were able to get this completely removed here. One more recent example of an epidermoid, we're doing a left retrosigmoid craniotomy here with an angled endoscope and able to look around corners more closely at the brainstem and work around cranial nerves. And you can see the post-op scan there, we're able to achieve a complete resection there and no more restricted diffusion. So the final thing we're doing with the endoscope at least in the posterior fossa is we will use this to as an adjunct to fourth ventricular tumors now. This was a not a keyhole approach but this was a patient with a fourth ventricular glio-neuronal tumor causing hydrocephalus. We'll start with a suboccipital crani and a telovilar approach but once we hit a limit in looking up into the fourth ventricle at the roof of the fourth and towards the aqueduct, rather than looking up at the top of the fourth ventricle, we'll start with a suboccipital crani and a telovilar approach. And towards the aqueduct, rather than do extensive vermian dissection, we'll put an angled endoscope in through the foramen of majandi. And you'll see when we go from a microscopic to endoscopic approach here. So we're now looking up towards the aqueduct, I can resect additional tumor from the roof of the fourth and I can make sure the aqueduct is open and that will give me confidence that this patient will not need a shunt and she's done well to date. And then after even medulloblastoma resection, we'll use an angled endoscope to look up and make sure that we've decompressed the aqueduct and roof of the fourth. So once you see patency of that aqueduct, it can be very helpful. So I'm going to just finish with some minimally invasive approaches to the ventricles here. As I mentioned earlier, I've transitioned to doing colloid cyst surgery all with a port-based surgeries. Not quite keyhole, but very small dural openings of about 14 millimeters here and docking a port in the lateral ventricle. And then using two-handed dissection to take this colloid cyst out. I prefer this to a CSF-based, a neuroendoscope channel approach where you're essentially using one hand to dissect and then you're in a water medium. So any bleeding will really cause a poor visualization. So this is the way I do almost all my colloid cysts now. And you can get a complete resection, no need for even an EVD or a CSF diversion in a case like this. And my favorite part is when the port is removed, the sulci come back together and white matter collapses. And finally, this was a patient with a ruptured cavernous angioma of the lateral and third ventricle. I want to just call your attention to the long axis of this cavernoma, which is why we chose a right to left port-based approach. You can see our trajectory there. So it's about a three centimeter craniotomy, but a very small dural opening. And then docking the port in the lateral ventricle, and then really working on extra capsular resection of the cavernoma, toggling over as we look over to the left side at the thalamus and hypothalamus there, and really trying to avoid the left fornix, which is the dominant side of fornix. I'll just zip ahead. Then we put an angled endoscope in just to look around and make sure we've resected the whole cavernoma, make sure there's no residual there. So really a combination of optical technology here. We go from routinely from exoscopic to endoscopic or microscopic to endoscopic, et cetera. So gross total resection. He did have a short-term memory deficit that improved several weeks later. So to go back to my initial point here, I don't think there's a true evolution. We use all of these interchangeably depending on what we're doing. And I think versatility is really key when you're doing minimally invasive tumor surgery. A lot of excitement in the future about advancing technology and miniaturization, robotics, multi-port surgery. So I hope I've been able to share with you some of our techniques for keyhole, minimally invasive endoscopic tumor surgery, and really with an emphasis on versatility and tailoring these approaches to your patients and pathology. So thank you, Dr. Zanonos, and to the AANS front row series, and to my colleague, Dr. Prevodello as well. Okay, that was a spectacular presentation. It really illustrates like this 360 refinement in approaches, how you really stalled down to what you actually need and just use that. And everything works out so beautifully. We're going to proceed with Dr. Prevodello now to discuss a little bit differently in terms of when to use ventral versus lateral approaches for certain skull-based lesions. Dr. Prevodello, take it away. Thanks so much, George. It's a beautiful presentation. It's amazing how our practice is so similar. I'm really happy to see all the, if I would say one aspect that I probably would do a little different is I still do intramuscular transcallosal for very small colloid cysts when the ventricles are not dilated. But I do port as well. I do port as well. Very good. I'm not intraventricular under the water, under the spinal fluid as well, because I do think that some of them I was not doing a good... I actually started getting recurrences in the ones that I removed just part of the walls of the cyst. So I agree with you, like a very, very great talk. So what I'm going to try to do here is to really basically go through cases and try to show my rationale when I did endonasal, when I did open, very similar to Dr. Zada's philosophy here. So I think the presentation from Dr. Zada really prepared for this and I don't need to go through much of the concepts. I can just skip directly into how we did as example. So for the most part, like I would say for more than 90% of the cases, pituitary denomas, we do that endonasal. Even when they invade the cavernous sinus, I think this is the concept that I think it became for the last 10, 15 years, more evident that we can actually go and follow this tumor into the cavernous sinus because the cranial nerves are pushed laterally, even the cranial nerve 6. This talk here, I'm not going to go much into the videos because I think the idea is to really show the philosophy. I would just show some key moments of the video here where we went beyond the media wall of the cavernous sinus that you can see right here. And when this tumor are suckable for pituitary denomas, you can really get amazing resections by coming endonasal. So here we open this in the face of the carotid there and you can see the media wall of the cavernous sinus. And that's the way we kind of go there and explore. In these cases, no CSF leak at the end and we use the collagen matrix for reconstruction. You can see that we really get nice resection. So this is something in general, like I think of multiple years ago, people consider a peeling of the middle faucet to enter this cavernous sinus and we do that very rarely now, only when not able to do endonasal. Another nuance of pituitary surgery is when there is tumor coming into the anterior skull base. Historically, these were cases that we did craniotomies to resect them. And nowadays, like Dr. Zada mentioned, we would do a planectomy here and attack this tumor. So the quick example here, going above that tumor and going to the subarachnoid space. So that is not a limitation for us to go endonasal and resect these tumors. And here, again, not going to go into much details, but really show that the ability that we have to go endonasal and resect these tumors, even if they go into the subarachnoid space. Here's the final view here of the supercellar with the dorsal aspect of the gland. And then, of course, we do reconstruction with a nasoceptor flap. In these cases, you can see here the reconstruction and this space actually had normal pituitary gland function after this type of surgery and no leakage with this type of reconstruction. Then when you see pituitary adenomas that I'm jumping already, like to the flavors that go a lot beyond the subarachnoid space, like they go like this, that's when there's no way. Like this is not something you'll be able to resect only endonasal. There's a very narrow kissing carotid arteries there. And you can follow this tumor as much as you can here, but it comes in an anterior angle and it becomes impossible. So this is an example where I combined an endonasal and an open approach. I'm not going to go in details here, but you can see in one point during surgery, coming endonasal, it was very suckable tumor. So I actually got excited. Maybe I can keep going and take it out, but look at the narrow space. And we're looking at the 70 degree endoscope all the way up. And this comes in the negative angle. You cannot just keep going. So we had to combine with an open approach. And then interestingly, I actually tried to come through the sylvan fissure. I can even come back here and show it to you. But as I came through the sylvan fissure, I got to see just the neck of the thing again. I actually had to do exactly like Dr. Zada. I put a port actually coming from the frontal area and resect the tumor. A little bit of residue around the anterior cerebral arteries there, but the combination of both approaches were excellent here to get a resection. Moving to meningiomas, I think for most of the meningiomas, we prefer endoscopic endonasal based on the fact that most of the time this tumor is located under the chiasm and between the optic nerves. And you get that good visualization of that space coming endonasal. I'm going to show some of the nuances when it goes beyond, particularly the anterior clinoid on top of the optic canal. That's when we would use other approaches. These are examples of the post-op MRI. We always like to see the stock and the gland preserved with the flap in position with the MRIs. These are examples of very standard tuberculum salaminae meningiomas that we resect endonasal. I think these are the first 10 on my career. We've done close to 100 these days. But you can see here like the stock preserved in these cases and even more complex going down, we were able to kind of reach down there and resect. A lot of people ask, how about the optic canal? I do think of the optic canal, we actually can address better coming endonasal because tuberculum salaminae meningiomas invade the medial aspect of the optic canals. So I used to use these daisy scissors to open the canal and then explore and decompress the nerve. Nowadays I use this, I have to disclose, I designed this and I do get royalties for the use of this, but I really love it. So I engage in like, I call it a can opener and I just slide it forward all the way to endoxine. I always struggle to come cutting in that negative angle and then I open up and you can see the optic nerve is nice and preserved there and then you can remove all the invasion of the meningioma located inside the canal. When it gets bigger and more invasive like going to the Sylvan Fisher, even like this, that's when you start considering, can I do this endonasal? These are the hard cases. This is a case that I prepared to do endonasal followed by a craniotomy. I prepared the family, I said if I do craniotomy only, this lady was 800 to 2800 bilateral, basically functionally blind and I felt that if I went endonasal and made the hole here to come back a few months later to take the rest, I thought that would be the best. That was many years ago. This is one of the first times that I thought about staging coming endonasal and coming open for cases and I was amazed because when I did this case, I was actually able to roll this tumor away from the Sylvan Fisher, see the bifurcation there and the optic nerve was so thin you could see the anterior cerebral arches through it but we didn't touch by coming endonasal. With the good exposure and the tumor not being so hard, we were able actually to get a complete resection of this tumor. I always show this case because for me this was one of the most important cases of my career for my own learning here to see the potential of what the endonasal can do. I got this whole tumor out and post-op this patient did great, improved a little bit the vision, able to read a book these days but it's still like, as you saw, there was a lot of damage already in that optic nerve but she did get some improvement and no problems, no leakage, see the stalk and the gland preserve and the nasoceptor flap. Then you think, wow, it can do everything endonasal and this is very important if you paid attention in Dr. Zada's presentation. You got to really look case by case and this is an example of a meningioma that's small and I've seen some neurosurgeons present, they go there all this just because they're small and these endonasal guys. This is a case that if you analyze is more on the plenum and this was actually invading the optic canal from the top and I analyzed this case several times and the optic nerve was actually pushed down by the tumor. So it's not a tuberculin cell meningioma, I mean it is, but the way it grew, it grew from the top of the optic nerve and it's easier to see when I had like moving the coronal plane and so we decided to do like a frontal approach with an eyebrow incision on this case because we landed right on the tumor protected the nerve. You can see we're able to open the canal, the optic nerve on this here and this is the post-op MRI. So it's very important to look case by case and understand the anatomy. I think one of the things we're saying for years is try to avoid crossing the plane of these nerves and by coming with a keyhole approach like Dr. Zadeh's style there, we were able to get this tumor out of there. This is another case that came when right at the beginning of the pandemic and everybody was afraid of doing endonasal cases, what's going on and that was one component but I thought about like well this optic nerve is really pushed laterally here, I could come endonasal, you know, usually I don't pay a lot of attention on the encasing of the arteries there, but one thing for me was very important. The fact that it was going beyond the optic canal and was invading the anterior clinoid and was young lady. So if I go endonasal here, I will leave disease laterally in this corner. So the optic nerve is this darker area here. See how much of the disease is laterally there and also invading the clinoid. So I did this with an open approach and you can see this is the post-op, the preservation of the stock and the optic nerve. This one I did not do with an eyebrow and the reason is because I want to do an anterior clinoidectomy and usually if I need to drill more, when you come in like with the eyebrow, you have, like Dr. Zadeh pointed out, an angle that is just from the front and when I take the clinoid, I like to have that terione combination where I can roll that clinoid out and for that reason, I did a more traditional incision with a small craniotomy, but removing that anterior clinoid to decompress as well. For the most part, plenum and some of the disease on the olfactory cleft here with the dema, if the patient lost the smell, which I test in every patient for the last, I think, seven years, we've been testing every patient with disease on the anterior scobes, we prefer endonasal when I know I can reach, if the tumor doesn't go beyond the meridian of the orbits or on top of the optic canals like I showed before, then endonasal. It's a good alternative because we don't manipulate the brain and the beauty is that you don't see a footprint on the brain afterwards. You know, the flare changes disappear and the cephalomalacia basically doesn't form. However, if your patient has normal smell like this patient, then I consider an open approach to try to preserve smell. So this is a patient that had a edema on the left side, a quite large tumor, lateral expansion of the base of this tumor, so we did an eyebrow. We did an eyebrow for him. He had the same problem, Dr. Zada. He had this, how do you call the follicular issue? Like he didn't have the complete follicular presence in his head, so it was a good alternative for him. He loved it. This patient loved it. He was like a motorcycle guy and the eyebrow incision barely could see and we were able to get the whole tumor for him. I've been watching him for more than, I think, five, six years and no recurrence and I was able to drill some of the hyperostosis from the top as well for him. So those are very important aspects, particularly smell. When you see a patient like these, then the smell is gone, but tumor is very large. And this is a patient I love to show this because it was done by another neurosurgeon here at Ohio State and 10 years before I met this patient. He did a bicoronal, bifrontal approach, did a good job, a little bit of more encephalomalacia, but not too bad, no DWI, but he left this part here. He left this hyperostosis, and that's what I like to show because this patient came to me 10 years later losing vision with that recurrence there. Also had a little powerful semen in joma that is irrelevant there, but it had a disulfatory component and a tuberculum cell component. And she was really like compromising her vision. So bicoronal already done before I came endonasal and it showed to me that I was able to get the whole part of the tumor that was growing back. And it showed to me the fact that these two approaches are complementary to each other, like the endonasal and the open approach. And the open approach, if you wanna remove everything, probably need to be more aggressive with the hyperostosis. So what I start doing cases like these that I see the hyperostosis laterally, a lot of hyperostosis, very vascular tumor, some edema, instead of like going bicoronal and attack this and leave some behind or doing endonasal and compromising by not really resecting the tumor completely. I've been doing this in these two stages. I go endonasal and I debulk the tumor, devascularize the tumor. The tumor collapses and I make sure that I don't manipulate the interface between the tumor and the brain. And then I come back with a small craniotomy in stage two and get that tumor out of there. And that's what I call the closest it gets from SIMSA-1 for these larger tumors. And I have done a series of these now with a very good outcome. I'm very pleased with this sequence of strategy for these patients using the two approaches. So for craniopharyngioma, I really agree with Dr. Zada. Most of the time we come endonasal. It's a midline disease that grows under the optic chiasm, sometimes even posterior where it grows from the stalk below the hypothalamus. And the endonasal view that you get really allows you to make decisions in preserving structures. And sometimes you need to make a decision to leave a little bit of disease, attach it to structures. So here's an example where we start and we find a pituitary stalk running in this type one we call, running under the tumor there. And then we identify the optic nerve anteriorly and then dissect around. And this is taking that tumor from the third ventricle and getting a very nice view from below. And you can see the walls of the hypothalamus there. So it works well for this tumor. We were able actually to preserve function for this patient. And these are examples of craniopharyngiomas for the most part that we would just go and use an endonasal approach with a vascularized reconstruction. Sometimes we preserve the stalk and the gland depending on the situation. Sometimes patients already have one hypopituitarism and we will just sacrifice the gland in order to resect the tumor. But then this is a recurrent that case I showed the video five years later came with this disease. And my fellow was like, let's go endonasal, let's go endonasal. And if you look here, there's attachment to the anterior cerebral, it's off centric. And I studied this well, the optic nerve appeared to be below the tumor. And we did an eyebrow here, right side as well. In this case, Dr. Zazada and explore here, the cistern, we found the carotid and just quickly here, just to demonstrate that the tumor was really sitting on top of the right optic nerve. And here's dissecting away. It would have been a disaster to come endonasal with a redo surgery and do that dissection there. So I was very pleased we came from the top and just showing here the bulking of the tumor, dissecting from the anterior cerebral artery and getting a complete resection for this patient. And you're closing the eyebrow incision, the subfrontal approach. Large cranial pharyngiomas, they're located in the third ventricle is another situation where an endonasal, it's very difficult to, because the optic nerve gives you a very narrow space in between the optic and the pituitary stalk. So for this case, for instance, I came with a transcalosal remove. I was trying to remove everything, but then I made a decision at the end to leave this piece because I was not able to find where the chiasm was. It was very adhering there. So I decided to leave this piece behind. And actually a few months later, I came back endonasal and took that out. So we were able to really complement again and have the complementation of coming endonasal and with the transcalosal approach. A few more demonstrations here of, this is a case here, we came transclival. And to go quickly here, because I know because of the time, George, what I'm gonna say for the most part, for transclival, we look at the cranial nerve. So for this meningioma, we're looking at the third nerve and sixth cranial nerve. If it's medial from those cranial nerves, we will go endonasal. And this is what we did here. We actually were able to observe the sixth nerve down here and the third nerve above. This was actually in between, off-centric is a petroclival meningioma. And we were able actually to remove this tumor that was growing for this patient. I actually watched this tumor first and then once it grew, I took it out. And here you can see a good example of an indication of a transclival approach for this patient. Other examples are chordomas. Chordomas in between the sixth cranial nerve. I'm not gonna go through the video here, do it to the time, but you can see this basically, we had the sixth nerves bilaterally protected on the back. Tumors there, meningiomas, there are pitreous more located in less clival. We'll go with the retrosig or sometimes anterior pitreosectomy, but definitely not with the endonasal. Same thing with this pitreoclival that has much more like implantation on pitreous than clival. So we also came with a retrosig approach. When it goes down for the skull base here near the foramen magnum, the concept that we have is like to be between the vertebral arches, as you see in the axial and above C1, C2. Basically, if I go endonasal, I only will take that apical ligament there and not destabilize this patient. So that's a very important concept. And this is another case here that I looked, where is the 12-cranial nerve? And the 12 is lateral to the tumor. So then this tumor was also small, but I was watching and it grew after a year. So I decided to take it out, young patient. So we came endonasal and I'm going to go just straight to the point here where you can see the 12-cranial nerve lateral here on the left side. And this is the meningioma that we landed right at the base and we were able to mobilize it out in respecting basically the position of the nerves. So a lot of our decision to make a summary is really about the neurovascular structures. Very important to have, not to cross that plane. You see the vertebrae back there. And like, if it is more lateral for it, like this one where the 12-cranial nerve may be in play here, then we came lateral in this situation with a far lateral approach. These are examples of a case that initially you look, oh, it's a form of magnum, it's right there. But if you pay attention, it's behind the odontoid. And more than that, the spinal cord is actually unterolaterally here. So for these, I actually did a Chiari approach. I removed the C2, just midline, removed C1 and part of C2, and I came from the back. And you can see here, there was just this area of attachment of the tumor. So we were able to go from behind, open the dura. This dura to dura here, if I remember correctly, was 18 minutes of surgery. The vertis pushed there, no need for far lateral, and the cord was pushed unterolateral. So this gives you like the important aspect of really pay attention, where are these structures when you indicate approaches? Now, just to finalize a little bit about albino fossa very quickly here, Georges, we're almost done, I promise. The trigeminal schwannomas. For me, the trigeminal schwannoma is a great example. I'm gonna pause here. I always look at the position of the carotid artery and how much of the tumor is in contact with the sphenoid sinus. So here is an example. I see this big corridor, so I know I can come here and resect this tumor endonasal. If the carotid is located guarding the tumor, then I would do a peeling of the middle fossa. Just here to show just the moment where we dissect here the sixth cranial nerve on top, and we were skeletonized the carotid, and we were able actually to go all the way to the posterior fossa there, and then get that whole tumor out and cover here with the nasal septal flap to see the post-op resection of the trigeminal schwannoma from there. Tumors that start on the bone, like chondrosarcomas, are perfect examples of what's coming endonasal, and really no need for a craniotomy. Basically, you come to the source of these tumors at the pitreoclival synchondrosis, and this is the post-op in these cases when we come and drill out, and we're able to go all the way lateral. If the tumor has an implantation behind the carotid, like I said, and has like a presence really on the middle cranial fossa, these are the ones we will do a peeling of the middle fossa like this, and go extra-dural to then reach the tumor. In this case, and you can see here, debulking the tumor and taking the tumor out. But basically, then we'll go open on these cases. So we'll do the approaching extra-dural, and then in this case, there was tumor intra-dural, so we had to open the dura as well. Chordomas that go from several places, we always start with the endonasal transclival. Most of the time, that starts more midline, and in this case, I was able to remove most of the tumor coming endonasal, was already a recurrent chordoma. But I left disease in the pitreous apex. I actually thought that this was the end of the tumor. There was a membrane, and the carotid was just hanging in the middle by coming endonasal. Patient had this meningioma associated, and I saw this lesion there that was residual. Instead of just give proton beam, like the same idea like Dr. Zada showed the case, you could just go ahead and do proton beam. But no, we did a peeling of the middle fossa and complemented with the open approach here. But see, this is V3, and we went with the Doppler, identified the carotid, protect the carotid, and take that chordoma that is recurring into the pitreous apex. We got a nice resection for this patient, and then sent to proton beam. This patient is still alive like seven, eight years later. Just to finalize then, to show that I showed a sequence of events, and we have a few cases where we actually did a combined. This is a view coming from a open approach. This is V3. This is a low-grade sarcoma that was actually mainly epidurally, and we have the retractor through a craniotomy here. This is the view from outside. And we combined with an endonasal at the same time. There was a lot of tumor. This is at the end of the resection where we resect the tumor, a low-grade sarcoma that was located here. And we are like connecting the dots and having some fun here. I got one are happy that we were able to help this patient. And this shows that for me is an example how complementary to each other is, like the endonasal and the open approaches. And invite you for our next course. Hopefully COVID is not gonna be a part of the story anymore. All these variants, they're happening. So hopefully, May of next year, you guys can come and be with us. Thanks so much. Dr. Peronello, there was another fantastic presentation. Again, such an overflow of like pearls just doing in half an hour. Yeah, yeah. Sorry, I have to go a little quick. One of my favorites was the one for the trigeminal schwannomas and the carotid artery. I think many people have been burned trying to do that one way or the other. And then it's a retrospect that you figure that out. Let's hold a couple of the questions and then see a couple of cases and see what our experts think. I just wanna comment really quickly. Dr. Peronello, great talk as always. I was learning a lot from you. I love this idea of the giant olfactory groove meningiomas that you debulk from below. And then you stage it and come back in from above. It's a great idea. So you don't get a CSF leak when you just work within the tumor, is that right? Is that the goal? No, you have to really be careful not to expose brain, by the way. It's very important. Like stay really into the tumor. Actually, the larger ones with a large base allows you actually sometimes finish the case with a nice debulk thing and you don't see any CSF. You gotta rely though in the navigation, right? Because you don't wanna leave too much behind and you don't wanna get through the capsule and get an artery on the other side. So that's the only aspect that you have to consider when you're doing those. But I'm very pleased with that. Have you used the endoscopic ultrasound for that reason to sort of know how much capsule you've left? I've done, I've done. Yeah, we've, and now that they have a better technology, I'm sure we've used more and more, but that's a great point. Yeah. All right, let's go over a couple of cases. So the first one is a young man. He did have a history of multiple cavernous malformations and a prior surgery for one of them and presented with headaches, a third nerve palsy and this was going on for three weeks. It was a complete palsy. He was on steroids, not really improve and he had this lesion here. Initially, actually he came from a hospital that was a little bit confusing about what this was. They originally thought it was an epidermal, but he was in history and everything. There was more and more evident that this was likely another cavernous malformation coming into the ventral midbrain. You see here exactly where it is. It's like in the ventral midbrain here. I got him in between the two. So we brought peduncles sort of right behind and we did do an angiogram to make sure it's not like a thrombosed aneurysm or something, but he did have prior imaging that didn't show aneurysm there, but you always want to make sure. Some important points here, kind of the solid components of the lesion were sort of tucked in in the medial side. I don't know if you can see my pointer as well, but on the medial side of the peduncle, and you can see here, this is the PCA and the SCA, and there's a good amount of, at least the cystic component, maybe some solid components that were above the level of the PCA and a pretty tall posterior clinoid processes as well. We also did fiber tracking and the corticospinal tracts were pushed posteriorly and it did look actually that this was on top of the oculomotor nerve, pushing it inferiorly and a little bit laterally. So here's a question now, would you treat this patient or would you just observe it with that deficit? And if yes, what would you think as an approach? Do you want to go first, Danny? Yeah, sure. So I would treat, I think, as you mentioned that it's not getting better, there's a lot of mass effect. It's very ventral, the fibers, motor fibers are posterior. The third nerve being pushed inferiorly is, I'm impressed that you were able to get to that conclusion because that's when you look at the imaging initially, it's hard to tell. It's pushing inferiorly, but I wonder if it's inferior medial or infralaterally there. Or lateral, it's a little bit hard to see, but if you look at this, it's a little bit more lateral than medial. Yeah, because here's what I think, if you go eyebrow or any craniotomy, it's very difficult to get to the interpeduncular fossa and to see the mammillary bodies where this is kind of nearby. I would favor in this case, because you could complement with an endoscope, like through that approach, but I would say that it's probably on my hands more like a very deep and far away. I would tend to order, to recommend a transposition of the pituitary gland on that right side, particularly. I've been doing hemitransposition. So what I would do is actually disconnect just the right side. I flip the gland to the side, remove the dorsum and that posterior clinoid and part of the tuberculum as well. So I have a full corridor from above to bottom. And I should be able to work even above the third, because that's usually where you land in more medial. So that's what I would do here to work in the interpeduncular fossa. In my opinion, the best approach for interpeduncular fossa is a pituitary transposition. Dave? Yeah, I agree with Danny. I think you could do an OZ. I mean, it's essentially getting to the basilar apex and as Danny said, an interpeduncular cistern. So you could do an OZ. An eyebrow is good for this, but it's a reach and you have to work around the infundibulum, but you can get through the membrane of liloquist to the basilar apex in P1. So that would work, but it is a reach past the optic nerves and infundibulum. So I would also do a trans-tuberculum, pituitary transposition on one side and take down the dorsum and posteroclinoid and you'll have a great view of the upper brainstem and cavernome. And yes, I would treat as well. Yeah, so I had extensive discussion with him about whether to do something or not, obviously. And, you know, I mean, some of the approaches that I was thinking about, one is just doing sub-temporal, but, you know, there were these solid components that were in the medial side of the peduncle and will be hard a little bit to see. Thought about also doing, again, an OZ, whether you do it like through, you know, an eyelid, et cetera, or like a full OZ. One of the issues, again, is like that, there were a decent amount of it that was above the level of P1. So you would, you know, either have to elevate the P1 or try and work in between the perforators, the P1 perforators, which is not ideal. You can consider it coming from the other side, but the basilar are just in a bad spot right here. It's kind of in the, exactly in the middle. And then again, I was thinking exactly what you suggested, and that's exactly what I ended up doing. The pituitary transposition, again, you get this beautiful use in the interperiduncular fulsa. And this is the case, you know, exposing like really widely to get access to the cavernous sinus, removing the middle clinoids on both sides. It also, a little bit of the upper planum, I'm sorry, the upper thymus. The upper column, yeah. Just to get this inferior view and be able to do the transposition and start resect the posterior clinoids. I did do, I did resect both posterior clinoids here. If I did this case again, I probably only had resected one of them. I, it was kind of at the beginning, and I didn't want to have as much room as possible, but again, doing the transposition here, transcavernous approach, coagulating and dividing the inferior alveoli seal, and then resecting the two posterior clinoid poses. Again, I resected both here. I probably didn't need to do both of them. And then coagulating the superior inter-cavernous and opening in the planet to make our way down. This, as both of you were describing, sort of doing this transposition, but preserving the medial wall, the cavernous sinus that potentially can preserve some of the venous outflow. That's the superior visceral artery there that is important to see and preserve. And then opening the membrane liliquid from this approach. Let me speed it up a little bit, but you can see the lesion here. This is the malformation. This is actually the third nerve that was pushed a little bit laterally. Yeah, I love your AR overlay of the third nerves. Really cool. And then, you know, the PECOM still did an ICG here to make sure it goes through most animals and all that, although we had an intergram, I still wasn't sure. But then opening into it, and this instrument also are very helpful with the grasp instruments. But most of the solid components were actually, again, tucked in the far end. And that's coming to the end of it. And multi-layered reconstruction. So one of the issues, again, I did respect both postural planners. Again, this was probably a mistake. I did manipulate probably the postural gland a little bit more. So he did have transient DI. And his third nerve got a little bit better, but he still has essentially a third nerve. He can open his eye, but he still have some ophthalmoparesis even a year after. But no evidence of recurrence. So another case, and I want to be respectful of everyone's time. I know it's been a long day for everyone. So just one last case. I know, you know, we discussed a little bit. One of the main discussion points in the topic of heated discussion is the supercellar meningioma. It's always tends to recur. It tends to revolve in people shouting at each other at conferences. But so we have this man, this middle-aged man who presented with pretty severe left optic neuropathy, also right hemianopsia. But you can see here the optic nerves. I'll show you the full MRIs if you need to see any more. But you see like there are optic nerves here essentially encased. And, you know, Dr. Perardello was talking a little bit earlier about, you know, this slight extension over the clinoid. You also can see like that there's a frank extension kind of very deep into the optic canals. This is a full MRI. Please let me know if you'd like me to stop somewhere to see some more details. But I guess we'll start with Gabe now. See what happens. How old is this patient, George? He is late 50s. Okay. Let's maybe go back to the sagittal please on the last slide or whatnot. So the base of this meningioma going, you know, all the way almost from the olfactory groove back to the back of the diaphragma is a long, almost on-plock meningioma. It's probably about four centimeters almost or over three at least. And then you have bilateral optic nerve invasion. This is going to be a very invasive tumor from what you can tell. You know, would I fault someone for doing an endonasely? No, I would do this one with an eyebrow. I can't see the frontal sinus morphology that well. If it's a large frontal sinus, I would probably do an OZ or a terianal. But I would do this one from above. I think you can do, you can drill out the optic canal, open the falciform ligament when you need to, and you have better control over the circumferential decompression, superior and lateral for the optic nerves. And then this is a case that needs radiation to me afterwards fractionated radiation. It may be a grade two tumor, but when you see complete encasement of the optic nerves like that, that's an important sign. So for me, this is a case from above and then really try to preserve those, the nerves of course, and then drill the canals open and then probably follow up with some fractionated radiation Yeah, I agree. I think I was, for the most part, when I look at the shape and the global picture of the tumor is a tumor that I would say I would do endonasel. It looks like most of the tumors I've done endonasel. But that aspect where the nerve is navigating through the tumor and there's very narrow nerves there with the tumor already outside, I would say that I probably will have a better control of the nerve by going open. What I do is I call the frontal lateral. So it's a terione with a little larger, I would say. The main reason is like I mentioned earlier, for some of these, I remove the clinoid to get a space to manipulate the nerve. Then I open up, I find the nerve ipsilateral. The left side is the worst side. I have a tendency to open the side that is worse on these cases. Some people go in the contralateral, but I rather start on the worst. And then I found the chiasm and I follow to the normal side and I find the nerve sometimes posterior and I roll the tumor forward by coming open. And I think it's safer in that perspective. So I probably would do it. That's what I would have done here. What did you do, Georgios? So excellent points. And that's exactly what I was thinking. One of the main things that also Dr. Ziada was talking about earlier was that that may be like an invasive tumor. If there's parasitization of the microvascular of the optic nerve, what I was thinking is that that's definitely not something I'd like to do blind. So that was my main concern, that if there's like mPLAC, meningioma on the optic nerve, that there was no plane, just trying to pull tumor from underneath the optic nerve. I was really scared about that, that that would devascularize the nerve and essentially cause an impact to the nerve, especially nerves that are pretty tedious like that. And for that reason, and that's my general tendency with this, the tumors to try endonasally, and every tumor is different as we discussed, but I guess my bias is to try as much as possible and visualize that microvasculature. Yeah. And that's, we ended up doing endonasal. I do like to try and go way up in the canals, like over the roof and expose the plant and sometimes it allows you to sort of push the, as you both know, push the dura up and then sort of even get that further exposure over the optics. And this thing, that two millimeter diamond, sometimes it allows you to get really into that, into that area. So like on the left side, that's the worst side here. Sort of really getting above the nerve. That also allows you to get a little bit further lateral. You can't really get it onto the dura, obviously of the anterior clinoid itself, but if tumors are sort of ballooning over the anterior clinoid, you know, you could potentially fall in there. The tumor wasn't very fibrous. It was somewhat fibrous. It wasn't completely suckable, but it was workable. And, you know, as expected, there was, it was insinuating between many things, but actually the planes weren't all that terrible. That was part of the tumor, but, you know, the most important part, again, that I was worried about is microvasculature. You know, again, I'm having a little bit of a hard time sort of just working between the nerves to really see, you know, these little vessels like coming from above without significantly manipulating the nerves. You know, an endoscopist is obviously like a very good adjunct and you can work with it, but sometimes it's a little bit hard to work in that tight corioleocumoral triangle or interoptic triangle with, you know, all these instruments there. These are, you know, some of the tumor that was. There was definitely tumor lateral to the nerve, right, Georges? Right, yeah, we went above it. I saw it. You kind of went and reached out there. Those planes, that's actually very nice how you got it off those optic nerves. I mean, I've seen them directly invade the nerves. Right, so, you know, yeah, this is obviously lucky. It wasn't, you know, I was lucky that it didn't directly invade them, but. Yeah, yeah, yeah, yeah, you need our knife, man. That's right. I was gonna say, yeah, that's a great explanation. Who makes that, Danny? Is this the X1 or no? Is it a different? No, no, that's the same brand that Georges was using there. It's like made in Japan. It's from Feather, Feather Blade. Yeah, this is going, again, above here. And, you know, I won't belabor this, but one of the issues that I did wrong in this case, sometimes I'd be hybrid with some of the gel foam. I think I did that a little bit more here, just to. But, Georges, let me ask you a question, because one thing you didn't show us, and I was thinking when I was answering, you didn't show a T2. And I bet you this tumor was not very ugly in T2. And I'm gonna ask you, like, if it was exactly the same, but a dark T2, would you go open then? I'm not, you mean in terms of the consistency? Yeah, more calcified, firm T2. That's the key, absolutely, always. I mean, I would say that, I would say still yes. And the reason is because that, if you go open, you even more have to rely on, you know, debulking and then working, you know, on the nerves. You really have to manipulate the nerves a little bit more, at least in. Yeah. No, it is. I don't have much. That's what I asked, yeah. But there's certainly no wrong way, you know, there are pros and cons to both. One of the things that I did do here, as I said, he actually woke up fine. But, you know, by the night, he actually started having decreased vision. And I took him back immediately. And one, he did not have a hematoma, but like the, I had put a little bit, you know, that gel actually sort of swell up. And we opened up everything and then removed some of it and repacked it. But we took him immediately. So fortunately, you know, he ultimately did do well. He was, I saw him at one year back and he did quite well, actually. His vision improved. And that was because again, the tumor was not invading directly the nerves. There was good arachnoid or platelet. So grade one, grade one tumor. Grade one meningioma, yes, grade one. That's an amazing outcome. Cause to me, it looked like it was wrapping all the way around, even going, was it going into the optic canals too, you said? Yeah, especially under that. Yeah, that's a great outcome. Yeah, he opened up, yeah. That's a very nice outcome, yeah. We just wound up with some, a couple of questions and then we'll have everyone go home. I guess the question first for Dr. Prevodello. So Denny, you spoke a little bit about it during your presentation, but you know, again, there's always significant controversy about, you know, smaller tumors are easier and therefore, you know, sometimes those are correlated with potentially biased outcomes, et cetera. So what, can you comment a little bit about your philosophy about smaller tumors in the same area, let's say a tuberculum, small tuberculum versus a small jugular tubercle versus a small, you know, as compared to a lateral approach, how do you tend to think about this? No, I think that, you know, it's interesting because if you have a very small, let's say a petroclival meningioma, small petroclival meningioma, they can be very difficult with an open approach. They actually might be more difficult. A small, any tumor ventral to the brainstem, if you go open, then the tumor did not create space for you. So that, and then if you come endonasal, you may be just like directly there. So it's something definitely we're taking consideration. So that's what I mentioned earlier because then people would think, oh, the small tumor, these guys that do endonasal, they're gonna try to go endonasal for that one. And I think the size is not as important as the location, right? So if you have a tumor that is small and is medial to the coronal nerves, then the endonasal usually will be your answer because the small ones that are medial to the coronal nerves will require extreme level of manipulation coming with any lateral open approach. So that's what is in my mind when I think about these cases, yeah. Exactly, great points that, you know, many times a larger tumor actually opens up the spaces and creates corridors for you if you're gonna do it open. So, and it actually, the smaller the tumor, the harder sometimes they are if you're gonna do it, you know, from a lateral approach to the same areas. We actually did a, just to compliment, we did a study once where we put a, like in a cadaver, we inflated a foley balloon in the pre-medullary system, like in the pre-punctine system, and we kept inflating. And we compared the different approaches to get to that area, kind of simulating different sizes of craniopharyngioma. And when we made it very large, you actually get very nice corridors coming from lateral because you could, it basically distended, created more space between these structures. So you have more space between PCOM and the third nerve, for instance, to enter medial versus the small ones that everything was compact on the sides. Right, right. Gabe, you know, in your developing career, how did you evolve in terms of, you know, trying to go more minimalistic and minimally invasive and keyhole versus open? Can you tell us a little bit about this growth? You know, did you- Yeah, well, I definitely have become more aggressive with extended endonasal. I think most of us have, and it's because of people like Danny and Paul, who I think have really, you know, demonstrated what could be done in a lot of ways that I've also become more aggressive with that. Other than that, I think, yeah, I try to do things with smaller and smaller craniotomies and approaches. And as I mentioned, versatility is key, but there haven't been a lot of other trends. I've always tried to incorporate these aspects into these cases. But I think if there's one trend I would look back on, I think it's doing more extended procedures as I feel more comfortable with a learning curve. And then I would say for meningiomas, I still think a good old-fashioned mini craniotomy sometimes is shorter for length of stay. I'd love to hear what you guys think about that, you know, because I still go back to it sometimes that craniotomy patients can go home post-op day two. And my extended cases, they, you know, with a lumbar drain, which I still use, can stay in house four or five days. And so I'd love to hear how that works for you, but here I still prefer a good craniotomy sometimes. No, I would like to mention that I just look at my olfactory groove numbers, because we're trying to work on a paper where we show endonasal for the ones that lost the smell, the combined approach for the large ones, and the craniotomy for the ones that we're trying to preserve the smell. And it's interesting, because then we did craniotomies for small tumors, because they still have smell, versus the endonasal that they were a little larger, and the length of stay is better for craniotomy on those cases. Yeah, because exactly for the reasons you just mentioned, you're worried about CSF leak, you don't want to discharge yet, there's a little wetness there, you want to observe another day. If you use a lumbar drain, then I'm sure then it's extended even longer. Yeah. Yeah, I think you both beautifully illustrated this, and spoke extensively about this, but much of the discussion about what approach to use is not that much. Well, if everything is equal, then one may lead you to have like a more or less length of stay for one reason versus the other, but I mean, it's always the key is to try and preserve, neurovascular function, right? Don't cross nerves, because those are the things that are going to be there for the long run. If someone stays a day longer or shorter. Agreed. So that's first, and if everything is the same, then yes, but it's very much true that sometimes there are craniotomy, people can be mobilized and get going much easier. And sometimes it's more comfortable, because like packing their nose, not being able to breathe, all those things, actually, it is very impactful in the quality of life, as opposed to craniotomy, there are not much moving parts, especially eyebrows, it doesn't involve the temporalis. People can go home and possibly want- But it makes a difference. And if you look at the data that my former fellow just finished with me, Steven McGill, he put together a lot of the outcomes for the tuberculin-salomon endowments. He is showing with the long-term that the recurrence rate is less, significantly less for endonasal approaches. So to your point, George, is exactly what you said, like you may end up with the risk of a leakage. For years, we've been talking about better outcomes for vision in this endonasal, but now we are seeing even better results long-term with less chance of recurrence. So I think that few extra stressful days with the patient, maybe staying a little longer at the end of the road, like long-term, is better for the patient. Yeah, I think that's a really good point. If you can get a Simpson 1 resection and better visual outcomes, then it seems to be worth it. Yeah, yeah. It's not free of recurrence. Now that I'm getting older here, like I just got one 10 years later that I started having a little bit of enhancement under the optic. Initially, I thought, ah, I think this is nothing, came back again, and it looks a little bigger, so I sent for radiation now, but he's intact. It does happen. It's not free of recurrence, but the endonasal, I think, overall, better long-term. Excellent. Thank you again so much, both of you, for sharing your precious time. Spectacular presentations and fantastic tips, surgical tips and tips in terms of philosophy. I'm sure everyone that viewed this here learned a lot. I certainly, again, learn a lot every time I hear you both present. And for everyone that's gonna be accessing this online at their leisure, I think that's gonna be a wonderful resource. I wish you a great night, and I wish to see you back and then soon live somewhere so we can catch up. Sounds good. Thank you so much, George. Danny, nice to see you. Thank you. Thank you, Gabby. Thank you, Georges. Bye, guys. Thank you. See you. Okay, bye.

skull-based surgery

endoscopic approaches

pituitary adenomas

tuberculum cell meningiomas

individualizing treatment

successful surgeries

brain tumors

endonasal approaches

open approaches

craniopharyngiomas

hyperostosis

radiation following surgery