I'll try to be fairly brief here. What I thought I would do is talk about a little equipoise about when I choose an approach through the nose versus approach transcranially. And so it's really about location, location, location. It's a real estate rule. And I'd just like to start off by reminding everybody that when you're talking about pituitary tumors, I think it's important, and we don't do much outpatient medicine now in residency training, but I see a lot of patients with tumors that I just follow. And I want to just make sure that everybody understands that these pituitary tumors are so common that about one in five people harbors one. And I think it's a fascinating question that what makes a tumor remain this size or what makes it grow. And I think it's really, they're so prevalent, I think it's really a question of the issue of senescence and what makes the tumor stop growing. So that's what we're looking at in the lab. But if you looked at our Utah population database, about one in six or 700 patients comes to treatment for a pituitary tumor. That's what the statistics are. And invasive adenomas are about 35% of them. And it doesn't necessarily indicate an aggressive phenotype. And carcinomas are rare, very rare, which metastases. So what are the risk factors for tumor growth? Obviously a younger patient, that's intuitive, a large adenoma, a high MIB1 index, and then P53 positivity. So if we have any of those features, we watch them very carefully or consider treating them. So if you look at the familiality of pituitary tumors, it's very interesting. We looked at this in the Utah normal population, the data bank. And if you have a patient with a pituitary tumor, the incidence of having a symptomatic pituitary tumor in one of their first degree relatives was much higher than the general population. So this is what I use to counsel my patients who always ask me, what are the chances that my children will have them? So let's talk about meningiomas. As Sam El-Mefti has aptly quoted, they're the good, the bad, and the ugly. Most of them are in this two categories, but some of them are just downright ugly. But I have the honor of doing this at Pocrates every year. And I look at the most recent literature. And it's amazing that if you look at incidental meningiomas, and we see so many of these nowadays because everybody's getting scans for mostly headache, and there's none that are specific to the base of the skull, none of these series. But if you look at them, there's a very consistent theme that about 60% of meningiomas have no growth over five years. So it's important to remember that whatever treatment you choose, you have to beat the natural history. And so I actually don't operate on incidental meningiomas. I follow them along. If they're symptomatic, I treat them. And if they're mildly symptomatic in old people, sometimes I just follow them along as well. So I think it gives you a background. It gives you some statistics to tell your patients that these are the chances, and we're going to watch you carefully. So the question is, in skull-based tumors, is do we do an aggressive removal or do a subtotal resection? And in incidental meningiomas, I just warn you, be careful in younger patients and those with surrounding T2 signal change, because that usually indicates that the p-arachnoid is breached, and they can be more adherent to the brain. So here's a case in point. Here's a 28-year-old woman, presents in third trimester of pregnancy with a six nerve palsy. She's got a cavernous sinus meningioma here. What do you do? Well, if you look at this scan on the left, she's pregnant. And so she was 35 weeks, so we induced her and delivered her baby, and her six nerve got better. And I've been following this tumor since. So I think it's just a case in point. And pregnancy is a real inducement for these tumors to grow. So what would you do with this case? Here's a 65-year-old woman with progressive visual loss. I just point this out because this is the basilar apex that's completely in the center of the tumor. I didn't know what to do with this. This was a doctor's mother, of course. And so what I did, she was otherwise asymptomatic from this. So all I did is I did a simple optic nerve decompression on this case. So here we go, left side, optic nerve. So we just remove the tumor, and then we'll also decompress the canal. And I have followed her now for many years since that time, and there's been no growth in the remaining tumor. So just to remind you that these can be very slow growing, and that the treatment can be worse than the disease in some cases. So let's talk about what in cases that we would do an open transbasal approach on. This is something that I think we talk about less nowadays that we're so involved with endoscopy. This is an old slide from many years ago. But I just point this out to let you know sort of the area of exposure that can be achieved if you decide to come from above. And I think that John just showed a case with anesthesio, that you get a beautiful view from above. So here's a large anterior skull basement angioma. We did a bifrontal craniotomy on this one. But I just show this because this gives you a beautiful view down into the nose. So instead of always just looking up, sometimes you can use your transcranial approach and look down as well. And we'll chase anesthesios down in the nose if they need a primary transcranial approach to do that. I think it was Blacklock that first showed this. He used to work at the MD Anderson some years ago. But when we were using endoscopic approaches less, we used to come from above, and we would remove the anterior skull base. And you get a beautiful view down to the region of the hard palate. And you can see it here in this cadaver dissection. Here's this phenoid nasal cartilage and hard palate. And then you can actually drill down and expose the entire basilar artery and drill the clivus out from above, too, and chase it down as well. Again, we're using the endoscopic approaches more. But if you come from above, you can actually look down into the paranasal sinuses. And so if you have a large anesthesia neuroblastoma, and it's in the brain, and we'll come from above, and we'll chase the rest of it out just coming from above. And this is you can come in, and you look around the corners, obviously, with an endoscope as well, if need be. So the limits of the approach are the orbits, and you can't look lateral to the orbits. And then anteriorly as well, and behind the pituitary gland. I think it's important to remember that you have a little bit of a blind spot. You can extend the transbasal. We do it very infrequently now. And then you actually remove more bone and avoid having to retract the frontal lobes of the brain as much. So what about the transnasal approach? And obviously, it's had a long history now, and it's an evolution. It's a 100-year evolution, really, of transnasal surgery. This is a picture from Schlaffer's original operation, where he just made a trap door the nose, removed the septum, and then marched right back to the region of the cella. And obviously, the focus with this was pituitary surgery initially. But this is an interesting slide. This is from 19 in the 20s, and this was a fellow named Oscar Hirsch, who was the first one to describe an endonasal approach. And he was very ingenious. He put a light source right up to the tumor, and he would operate on these patients awake in his office, and he would sit them up, which was very clever, because it reduces the venous bleeding. And had a remarkable success. And at the time when Cushing had stopped doing the endonasal approach, he kept it going, and then taught it to Guillaume, and then Guillaume learned it from Dot, who then taught it to Hardy, and then added the refinements that brought it into the modern age. And you could imagine that before decent visualization, we wouldn't be able to remove a microadenoma and preserve the pituitary gland. So this whole notion of selective adenomectomy was really just after the advent of the microscope into transnasal surgery. And about 1980, we started to expand the limits of the transnasal approach. And there's been this minimalism with endoscopy and radiosurgery, and then maximalism by increasing the exposure with different approaches. But we were exposing these areas, as John mentioned, but using the microscope before the endoscope. And I just show this slide, because this is 20 years ago now, and I was a young fellow, and Taka Fukushima and I removed that tumor with the transplanum approach that John just showed you with a microscope. And so we actually had started to do this before the endoscope was routinely used. And obviously, craniopharyngiomas, as John just beautifully showed you, if you look at the types of cases that you'll be able to address through the nose, either with an endoscope or a microscope, this gives you an example of the different pathologies that we did in our large series. But the real risk is obviously internal carotid artery hemorrhage, and then CSF fistula. Because if you come from a blow, it's harder to close, and the CSF leak rate is about five times what our normal CSF leak rate would be for pituitary surgery. So it's a significant risk, and we've got it down as low as we've been able to, but I still can't get any lower than about 5% right now myself for extended endonasal approaches. I just show you this because this is a fascinating video. This is Gerard Guillot, who is a very innovative neurosurgeon in Paris. And this is a video from 1962 that I'll show you that sort of resets the dial, I think, on where skull base endoscopic surgery. So this was in Hospital Fauche in Paris. And so what you'll see here is he's going to do an endonasal pituitary approach with an endoscope. So he's doing it with an ENT surgeon. You can't hear the video or the audio here. But here's the endoscopic view. He opens the floor of the cella. The neurosurgeon takes over, and now they remove the tumor. So it's remarkable that, you know, it sort of lay fallow for so long in my mind. But that was in 1962. And here's the publications on endoscopic and pituitary surgery and skull base surgery. And really, just the last two decades, really, it's really come into its own. And as I said, there's advantages to both the microscope and the endoscope. You definitely see better. Your surgeon's eye is at the surgical site. You can look around corners, and you've got better lighting. The trouble with the endoscope, I'll show you. And I think it's important to have equipoise and to be able to use both and use them both effectively. This is a study performed by one of my residents about 15 or 20 years ago now that showed that no matter what approach you use, you get definitely a better view with the endoscope. You can see it much better. It's because it puts your eye right where you're operating. And so the ENT surgeons were really the ones that helped us really learn how to use this technique. And I've had just the great pleasure of working with some terrific ENT people over my career. And here's a JNA, for instance. And this is ready-made perfect for an endoscopic approach. We would have to take the face apart 20 years ago to remove this, but you can do this through different portals of using the endonasal approach here. Here's the tumor in the back of the nasopharynx. Here's the middle turbinate. And then coming in through a transmaxillary approach with a little portal as well. And combining these cavities, this is Richard Orlandi and I removing this tumor. And then taking it off the skull base using both of these cavities. Now this tumor is too big to be removed just through the nostril or through the little Caldwell maxillotomy hole that we made. So we'll just push the tumor down into the oropharynx and retrieve it that way. But I think the endoscope has really revolutionized all of paranasal sinus surgery and anterior skull base surgery. It's remarkable because of the visualization. And then you get this beautiful wide-angle view. And I just want to remind everybody that this is the reason that you have the wide-angle view. And you'll notice this when you start to learn to use the endoscope. And this is a checkerboard, a symmetric checkerboard, but this is the reason is it compresses the outer limits because it's a wide angle. So let me just mention a few words about these transcribiform operations. So I think when we choose a meningioma to remove through the transcribiform, one other thing you want to think about is the sense of smell. Because if you come through the cribriform plate, you're going to abolish the sense of smell if there's any left. So if they do have smell, I come from the side that's the worst smell, and I come unilateral and try to lift it up and preserve the contralateral olfactory tract. This lady had lost her sense of smell. The tumor was enlarging. So this is a reasonable one. The other thing I want to mention is you want to see the relationship of the dural tail to the region of the orbits. Because when I decide whether I'm going to come in from above or below, it depends on how far that dural tail goes. So this one, I thought, could be done reasonably from below. And it's a simple operation. You just come in, you use your image guidance to just find exactly where the attachment is, and then we'll remove that area, and then remove that. And here's her post-op MRI. But let's look at this patient. And this is just a caveat. This is one of the things that I've learned over the years, is that you've got to be very careful with meningiomas. Here's a 56-year-old woman. She's got renal failure, so she didn't have contrast. She's got this tuberculum tumor. I thought, well, reasonable, but the tumor's going a little bit lateral here. So we do an endoscopic approach. We remove it completely. I chased the tumor over on top of the clinoid, though, and I had trouble grabbing it over there. But the scan I can show you looks fine. And I could tell you I was unsure about that clinoid, even though the scan looked fine. And here we are three layers later with tumor on the clinoid and visual loss. And I had to do a transcranial approach to salvage this and remove the tumor and decompress her optic nerve. So this is a slide just to demonstrate what you can see and what you can't from below. So from below, you get a beautiful view of the optic nerves inferiorly and medially. What you can't do is achieve much laterally over the optic nerve, because you're limited. And you can see it, but you can't operate very well out there. But you get a beautiful view. And so I think meningiomas are a particularly tricky one. And you've got to be careful about the cases you choose. The other thing is optic canal involvement. So here's an interesting case. I think this probably could be done either way. This is a tuberculin meningioma. The tumor's coming into the optic canal. But notice it's coming into the optic canal on the medial side here. And you'll be able to see that fine. What you won't be able to get is if there's tumor involving this dura here, because you won't be able to reach over and grab it and take a big margin around it like you would normally from above. So here's an example of what we try to do from above. We're very aggressive when we remove these tumors transcranially. And I think the real issue in these cases is whether you can achieve the equivalent Simpson grade removal from below. And just a couple of points that I want to bring up is that these tumors usually attach a little bit laterally. And they're often in this chiasmal depression here. And you'll see where the attachment is. So what I'm doing, here's the right side, right optic nerve. I'm decompressing the tumor. And then I'm bringing the tumor out from underneath the optic nerve. And then we'll do a complete removal of all the dura around the optic nerve. And I think that that is harder to achieve from below. So we open up here, completely remove the tumor from around the nerve in this area. And you want to decompress by indirectly moving the tumor away from underneath the nerve. And then we'll drill the canal out completely on this side. Because where these people fail is early recurrence around the optic nerve and around this area of the canal. So here's the area of attachment I was saying. It's usually eccentric to one side. I'll go ahead now and completely decompress the canal from above. Take the dura flap down. We'll drill out the nerve completely. And remove all the dura, both above and below the nerve. So ultimately, you're left with just the nerve. And you've removed all the dura around it completely. So the other point that I wanted to make about craniopharyngiomas, and I see this all the time in the literature, is you want to be able to predict where the tumor is coming from. And I'm going to show this case as an example. So here's a 38-year-old man who presents with confusion. And he's got this lesion that we thought was a craniopharyngioma. It's partially cystic, partially solid. It's supercellar. But I want to just point out here that the nerve or the pituitary stalk is in its native position. And if this tumor is arising in the supercellar cistern, or from the stalk, or from the inferior hypothalamus area, it will distort the position of the pituitary stalk. So here's another example. You see it's foreshortening the stalk. This is a very good key that the tumor is within the third ventricle. So I would specifically not choose a transnasal approach on this. The reason being that you're going to come through, and you're going to take out the floor of the third ventricle to get at that tumor. And that's unnecessary. So what we'll do, and I'll just show you this case as an example. Here we'll come in, do a translaminar terminalis in this particular case. But we would choose a transcranial approach, however you'd want to approach this, to be able to remove the tumor. So we're going to open up the laminar terminalis here. And then we get onto the tumor immediately. You can see that there's nothing in the supercellar cistern. It's all within the third ventricle itself. So I'm pulling the capsule of the tumor out here. There's the capsule, and then you'll see the remaining solid portion of the tumor coming into view. There's the solid portion. And you'll see when we remove this tumor completely, and we can take an endoscope in and look around the corners if we need to, but the floor is intact. And this patient had DI for a couple of weeks, and then it stopped, and the endocrine studies were okay after that. The floor is completely intact. Then the other point that I wanted to make before we close is just this whole issue of fine microsurgical dissection using the endoscope and the microscope. And this was something that I noticed when I was teaching residents with the endoscope and the microscope, that they had trouble, and I wondered if it was the lever arm of the length of the instruments through the nose that was making it harder for them to be as accurate as they would be with the microscope. But we did a series of these sort of dexterity studies and surgical dexterity studies using residents and then using experienced surgeons. And we used these standard movement disorder tests, the spiral, the tracing, the dot-touch test, and then we looked at different lengths of instruments that they were using, and then using the microscope versus the endoscope and visualization. And what you find is some very interesting things. So the length of the instrument didn't make that big a difference when we tested them, that they could overcome that fine, which was a little surprising to me, because I thought that was going to be the major issue. The major issue was when you use a microscope and an endoscope, here's side-to-side comparison. And these are naive junior residents to both techniques, okay? So they're not experienced in either techniques. You can see that using the microscope is a little easier for them to start with. And I think the reason for that is it's because it's a 2D versus 3D issue. And then if you do an expert surgeon in either technique, this is what you find. So we had people, and we had multiple people that were experts in either endoscope or microscope or both, and you find this is an interesting phenomenon, that when you use endoscopic visualization it takes a lot longer. And it's because I think you're hunting and pecking the whole time. You're looking for your place. And once you get out of that center beam, then you become very experienced with finding your way, and you use other techniques like moving the endoscope back and forth to make up for the 3D difference. But you're still hunting and pecking a little bit, and so it takes a lot longer. So this is what we see when we do endoscopic surgery, is it takes a lot longer because you're pulling the endoscope in and out and cleaning it, of course, but you're also looking for, you're searching for your target a little bit. So I think the way around this, obviously, is 3D endoscopes, and there is one that's actually out now, and we certainly have used that. I find it a little bit hard to use. I still get a headache with it, so it's not quite true. But I think this will be the equalizer, because once we have an endoscopic view that we're able to put our eye where we're operating and have 3D, then that's going to be the best of both worlds. So I think that's where we're going to go, and I'm going to just, I think, stop it here. Thanks very much.

pituitary tumors

meningiomas

tumor characteristics

tumor location

familiality of pituitary tumors

skull-based tumors