So, it is a great pleasure to start off the lectures and talk about a topic that I love to talk about. So, what I'm going to be talking about really is the point of view of endoscopic endonasal surgery. What can be done through that approach and talk, I can't help it, I'm going to talk about what my biases are about what I think can be done and what I think is a proper approach. You know, the fact is, is that, and it starts really with the very basic approach which is the transphenoidal. And if you know how, and in your practice, know how to do a transphenoidal and do it well, at least from the endonasal, endoscopic point of view, if you start with that, then you can start understanding how you can do more, how you can go along the anterior cranial base, transplanum, transcribiform, and even transmaxillary. But what I focus on, and what I'll focus on in this lecture really is, how do I do the basic approach for a transphenoidal and for a pituitary? And I'll run through, I'll run through not just the approach but tumor resection technique. I think it's useful to know this is the most, the pituitary is the most basic of the endonasal, endoscopic skull base approaches. So that's what I'll talk about, but I'll try to hit on the resection of most of these. Having Juan here is a huge benefit because really he and his group are really the leading center in performing these surgeries. And getting his perspective, I think, is a huge benefit to these exposures. Most of these, the experience that I have is with pituitary tumors, but having done a lot of them in a relatively short period of time, I've had the opportunity to see, well, what can we do through this endonasal approach as well? And we'll talk about that. So this is the basic approach that I use. This is what most people do. So this, can I just see a show of hands? How many of you all are doing, at your programs, doing endoscopic endonasal work? Right, so, right, most people are. It's not the answer to all the world's problems. There are some cases that, in my opinion, are done better with a microscope, and I'm happy to discuss that. Using both nostrils, I think, is the right way to do it, having tried to do it early in my career through one nostril. The key is the size of the sphenoidotomy needs to be appropriate for the resection. You know, the difference between a microscope and an endoscope, the microscope is outside of the field. And so the necessary exposure of the sphenoid is smaller with a microscopic approach than with an endoscopic approach. So often people talked about this as a minimally invasive approach. It's not. The amount of anatomy that you have to remove in order to have enough room to maneuver and account for an extra instrument being in there, namely the endoscope, is more than with a microscope. So for most pituitary tumors, I don't remove the middle turbinate. However, there are advantages to removing the middle turbinate, and for most things you shouldn't have a religious view of your approach. There are times, for sure, for even pituitary tumors where removing the middle turbinate is a benefit. And for a regular pituitary tumor, I don't harvest a nasoceptal flap. However, you sure need to know how to harvest a nasoceptal flap to be able to do bigger cases. So there are lots of ways to set up a room. Happy to send the PDF of this talk to you all if you want to see it, if you think it would be useful. This is not the setup I use, but a lot of people will use a setup where surgeons stand on either side of the patient. That is a very useful way to operate that happens to be a good, creates a good working relationship between the person using the endoscope and the surgeon. I set it up a little bit differently where I stand directly in front of the patient's face, which is a less convenient. So the surgeon is standing here. It's a less convenient place for the endoscopist to stand, much more uncomfortable for the person driving the scope. But it is supremely comfortable for the surgeon. I think that there are advantages to that. Being a selfish guy, I like being comfortable. When you start doing these cases, you'll use different scopes. There are different length scopes that are used. Usually for the approach, you use a shorter scope than when you're doing the resection and using a person who's driving the scope and a person who's operating. By having a longer scope, you keep the endoscopist's hands away from the nose and out of your way. So these are the sequences for a standard transferonoidal. So how do I get there? The way I get there is by first lateralizing not just the middle turbinate. Again, I used to think that you really shouldn't remove the middle turbinate. I'm feeling, although I continue to not remove it, I'm not so sure it is such a big point anymore. I lateralize the inferior turbinate in addition, though. And that, I think, can really increase the amount of room you have inside the nose. And I started lateralizing it in cadaveric courses just to have enough room. And then I realized, well, if it makes enough room when I'm teaching these courses, why am I not doing them in the OR? And we'll do that to start off with. I do remove the inferior portion of the superior turbinate. You'll see why. Essentially, it gives a larger exposure of the anterior wall of the sphenoid sinus, so you can do a larger sphenoidotomy. So let's just go over the anatomy that you're going to be seeing and seeing in the lab tomorrow, because this is what you all should be doing. In my opinion, this is a good way of approaching the sphenoid. So that's middle turbinate, injecting it. And I'll go in and first medialize the inferior turbinate, then lateralize it. So if you do that, it really gives much more room inside the nose, not more room than if you remove the middle turbinate. But still, if you're not removing the middle turbinate, that maneuver is quite helpful. I'll lateralize the middle turbinate, not medialize it first. Go straight to lateralizing. You can see the superior turbinate coming in view and flipping the freer in the other direction, getting into what's called the superior meatus and lateralizing to isolate that superior turbinate. So this is sphenoid recess. There's the ostium. The ostium is always lower, people, than you think it is. The mistake in endoscopy is going too high early. It's always lower. Stay on the inferior border of that middle turbinate. So I will, after lateralizing the inferior turbinate, lateralizing the middle turbinate, identifying that superior turbinate and injecting it, which is the hardest part of the case, is getting that. If I had unedited this, how this got to there, it would have taken the entire lecture. So I will inject the superior turbinate, inject the septum, and then remove the inferior half of the superior turbinate. And you can see what that does is it exposes into the posterior ethmoids. And so you can see and more deliberately open the anterior wall of the sphenoid sinus as you expand the sphenoid ostium. So after I lateralize inferior turbinate, lateralize middle turbinate, find the superior turbinate, bite it, take the soft tissue shaver, make it go away, I expand that sphenoidotomy, then it's time to take the septum. That's probably too high power. Never to smell again. But I take that septum. So after you've started your sphenoidotomy and you know where the sphenoid is, I'll take that septum. Soft tissue shaver is a wonderful instrument. One of the key points is to elevate the mucosa off of the sphenoid ethmoid recess. If you're going to do a nasoseptal flap, you don't want to have bagged it. And if you've, the artery runs with the mucosa and it's wise to separate the mucosa and just bite bone. And then you simply repeat that on the other side. Does that make sense to everybody? So after you've done that, what you have to do is create one cavity. You create one cavity by removing the rostrum of the sphenoid. This is now in the left nostril. Already septectomy on the other side, removing the mucosa of the septum on the other side. And then you're left with the keel. It's a good idea, again, to destabilize the keel by biting inferiorly. And I like taking a straight through cut and biting superiorly as well so that as you're torquing this, it fractures easily and you don't fracture into the anterior skull base. All right, so you've created one common cavity, right? So this is, these are the steps that we've just talked about, right? Lateralizing inferior turbinate, middle turbinate, removing a portion of the superior turbinate so that you can do a more deliberate opening of the sphenoid sinus, initial sphenoidotomy, partial septectomy, do the same thing on the other side. And then what you're doing is enlarging the sphenoid, okay? And the question always is, well, how big of a sphenoidotomy do I need to do in order to take out a pituitary tumor? Well, I have certain biases about that. And for me, I'll simply tell you what, how I define a proper sphenoidotomy, okay? But the mistakes are, and the mistake I made early in my career was trying to do a minimally invasive approach. And I kept trying to do this small approach and never was happy with the exposure that I was getting. And once I realized that really the point is taking out the tumor, that freed me significantly. If you do not do a proper exposure, you will run into this problem. Do you see this, the instrument whipping around something? What it's whipping around is the endoscope. And it's whipping around the endoscope because I haven't done a big enough exposure. And in part, and you can argue that it's in part because the sphenoidotomy isn't big enough. It may also be because I didn't remove the middle turbinate, which then forced the endoscope to take a more medial position and be more in my way. One of the advantages of taking out the middle turbinate is that the endoscope can sit more laterally inside the nose. So don't put yourself in that position. So superiorly, the definition of this, for me, I know I've gone high enough when I can see most of the planum using a zero-degree endoscope sitting outside the sphenoid sinus. If you can see most of the planum, you're high enough. You don't have to see all of it. This is more than is necessary for most pituitary tumors, but not too much for a transplanum approach. But laterally, I like to be able to see both OCRs if they're pneumatized. I want to see where they are. And the superior exposure is seeing most of the planum. Lateral exposure is being able to see the OCRs. And inferiorly, it's simply being able to get your instruments below the tumor. Once you can reliably get your instruments below the tumor, you likely have gone low enough. So again, I will lift the mucosa off of the anterior wall of the sphenoid sinus so that I don't get a posterior nasal branch injury, bag my septum, my nasoseptal flap. But also what it does is it puts you at risk for postoperative epistaxis. So again, superior exposure, see most of the planum. Lateral exposure, see the OCRs. It's simply you need to be able to expose below the tumor. So for these three patients, you need to expose a different amount inferiorly. Here the tumor goes almost to the floor, so you need to expose there. In this patient, who had apoplexy, first this patient probably didn't need surgery. But the exposure to the floor is a waste of time. You only need to get down to here to properly take care of this tumor. So again, I err on being too low when you do these exposures. When I'm doing the exposures myself, I try to do as much of the exposure from one nostril as possible before moving to the other. And the Pittsburgh group really pushed warm irrigation. It makes a huge difference in terms of hemostasis. Remember, as your field gets more red, it absorbs the light, it gets darker, you can't see. So irrigating and getting your field clean is what you need to do. These are just small points. But for me, I think a lot of the small points really are helpful. I'm a right-handed surgeon. If I know, and we're looking at the cella, if I know where midline is and know where the carotid is, I will tend to open in the inferior right or inferior left-hand side of the cella so that most of my bites with a punch are up and forehand punches. And when I... You don't have to drill. This was thin enough. You could have taken a chisel and out-fractured it. But as you are opening the dura or opening the bony cella, it is important to do your bony exposure high enough and laterally enough. And you will see a reflection of the dura as you go superiorly. You should look for that reflection. It's not that every tumor has to be removed that way, but a proper exposure I think includes seeing that dura reflection superiorly and laterally. So the carotid, this is off towards the right side. Carotid is going to be here. And if you can see those dura reflections, then you know that you have exposed the dura properly. Before opening the dura, if I go on very laterally, the Doppler is a nice tool to use to make sure you're opening it safely. And the only point I make about opening the dura is I try to not blast through. I try to maintain the capsule of the tumor or the capsule of the pituitary if it's a microadenoma. I try not to cut into the tumor with the dural opening. It does take longer, and I'm not always successful. But it's quite useful if you're later going to be searching for the pseudocapsule of the tumor to not have gone directly into the tumor on the dural opening. Taking a little bit of time on dural opening can be very helpful. Tumor resection. How do you take out a pituitary tumor? These are easy tumors, so, you know, maybe I shouldn't belabor the point too much. But I'm going to talk about it a little bit, if it's okay with you all. So there are two basic ways you can take out a pituitary tumor. You can take it out piecemeal, right? Big tumor, just take it out in pieces. That's going to work almost every time. These are not malignant tumors. You can get a very good piecemeal resection of a tumor. But I would advocate, even with macrodenomas, whenever you can, remove it with the pseudocapsule of the tumor. You should. And there are... This is a small tumor where I didn't really... I removed it piecemeal, but not in a sequential way. The sequential way is removing the floor first, going front to back, then going out to the sides, removing each side, and then removing the top, right? You don't want to remove the top of a tumor first so that the diaphragm drops and you can't see a darn thing. You need to remove it floor, wings, top. This tumor really actually was such a soft tumor, it could have been removed in any way at all, and it would have been successful. Even with the tumor removed, the diaphragm didn't fall. It is awfully nice with the endoscope being able to look into the surgical cavity. I don't like an endoscope holder. I like being able to go in and look to the other side, look cross-court, and look for tumor remnants. The other advantage is at times you will see a large hole in the cavernous sinus wall. Obviously, once tumor is in that region, you're not going to, if this was acromegaly, you're not going to cure the patient long-term. But you can, with an angled scope and with this cross-court view, get a decent view into the cavernous sinus and more deliberately remove tumor than blindly remove tumor from the cavernous sinus, and I do think that is an advantage. One of the other advantages is being able to look in. This is an important point. Diaphragm, right cavernous sinus wall. This here, this gutter is the place that tumor will be left behind. You need to open that area and look in those gutters. This gutter was easy to look into, easy to know, but on the other side, a little bit harder to see. So the pseudocapsule, the resection of tumors using the pseudocapsule, I think is a key way to remove ACTH tumors. I got to tell you, this is one place that, although I'm persisting trying, I don't take these tumors out better than Ed Oldfield does, and he uses the microscope, sublibial approach, wide exposure, and does them beautifully, and beautifully every time. I have to wait for a case to potentially edit and show at a conference. And this is one of my better attempts, and this would look like one of his worst attempts at using the pseudocapsule. But I learn something new every day from him, and it's an honor and pleasure to work with him. So, again, if you can stay outside the capsule, here's the little adenoma here. Staying outside of it, not bursting into it, say, oh, I found the tumor, and then removing it, but staying around the outside of the tumor is the way to reliably remove these tumors and attain a long-term remission. You can also do that with macroadenomas. It's just that you're going to have to internally debulk it before. It's good to, if you haven't burst into the tumor with dural opening, you then find that capsule of the tumor. After you've defined the capsule a little bit, go back, internally debulk it. Go back. This is going around the left side of the tumor. Normal gland tumor. There's normal gland, right? And if you remove... This was an intercellular macroadenoma. You can do this as well for larger tumors. Often, a very firm tumor is great to remove this way and is something that I think you should attempt to do. For pituitary tumors, as you're starting to do them, patients that are older have better pneumatized sphenoid sinuses. Try to choose them. An ACTH adenoma is probably not, shouldn't be your first case coming out into practice. Those are tough cases. Nonfunctioning adenomas are tumors that you should focus on, in my opinion. So what about all the other things? So if you get good at these techniques, I think looking at the rest of the skull base is certainly possible to do, but I would advocate getting good at this first. I would. It's not very much bone to remove, though, to go transplant them. So that is primarily going to be done for meningiomas. Craniopharyngiomas are a rare tumor, right? So there are only about 300 new cases in the U.S. each year, but meningiomas you'll see all the time. And the question is, well, which meningiomas should be done this way and which shouldn't? And I think that Dr. Caldwell will discuss that some. The exposure for a craniopharyngioma, I think, is reasonably done this way. I'm not as good with the computer to be able to draw a trapezoid, but really the exposure really should follow. This is the optic nerve or the optic canal. This is... And so your bony exposure actually should follow that, and it narrows as you get towards the tuberculum. And so really it's a trapezoidal shape. There are beautiful drills that work in the nose to do an exposure, but this is the kind of exposure you're going to need to do. This is a nice drill where the irrigation goes right through the shaft and keeps the drill cool. There's a punch called a foramenotomy punch that Chris Schaffrey uses that I steal when I do these cases that is great to backbite along the planum. But that's the kind of exposure that you want to get when you're doing a meningioma or a craniopharyngioma. The key is getting out of there. Before I fully open the dura, I measure the defect and then this is at the end of the case. Lots of people use a fasciolata. That's probably better than using something like this, which is duragen. I tend to use the expensive products that are used instead of doing an autologous graft, but you've got to be able to do these nasoceptal flaps. They really reduce the incidence of postoperative CSF leaks dramatically. How you hold them in place is a dealer's choice. I tend to not use balloons anymore because I necrosed a flap by keeping a balloon in too tight for too long and it took it out and the flap was dead. So I tend to put them in. I've stopped using the nasal rockets even and have had success. So craniopharyngiomas. Let me show you a couple cases. This is a craniopharyngioma, a decent-sized craniopharyngioma. To approach this, it is very helpful to go across the plenum. This is dissecting around the left side of the tumor. You can see PCOM. And it's simply a matter, like anything, of trying to dissect around the tumor, internally debulking it, and pulling down the sides. That's superior hypothesial artery. Oh, look, did I get it? Might have. Third nerve you can see on the left side there. Brain stem. That's the chiasm there. And again, it's just a matter of getting the tumor smaller and progressively dissecting it. In the end, you can get very satisfactory resections of these tumors. And there is an advantage to getting straight into the tumor to do these. This kind of craniopharyngioma I was not able to completely remove. Did, as it was invasive of the third ventricular wall. You can see there. I simply had to make a choice of when enough was enough. In the end, the intraoperative view was okay. You can see there's obvious residual tumor. The post-op MRI looked a lot better than the intraoperative view. I was grateful to our radiologists for that. Meningiomas, again, I think this is one that you could debate. Should it be done from above or below? I think so much of it was visible there. I think it was a reasonable case to do from below. On the rare occasion to be able to use a bipolar in the nose. Oh, my God, that is rare to be able to and wonderful when you can. This was a little bit more firm. You can see left optic nerve. There are lots of instruments to try to deal with a tumor that's more firm. But you just have to be willing to be patient. These are not fast cases necessarily. I'll make it look faster in a video. Here is the pituitary stalk, left optic nerve, A1 on the left. It's just basic surgery, cutting it, making it smaller. But you can get very nice resections with these. Transcripiform approaches, I must say for meningiomas, I'm not an enthusiast. I don't have a problem with other people doing it. But for most, I have not found a perfect, decent-sized olfactory groove meningioma that I thought should be done by me from below. This case I, in the end, was planning because there was a lot of tumor in the nose. But I wanted to start off from above. And it turns out the whole darn thing came out just from above. And I thought it would be a great case for endonasal for a portion of it. But there was no portion of it that was useful. I think that likely, in my mind, a tumor that is almost all intracranial is most reasonable to be done transcranially. If there happened to be one that grew down, sure, I get it. You probably could do that from below. I just haven't found that tumor yet. I'm happy to take the referral for it. It's great, though. An endonasal approach is great for an encephalocele like this person had with recurrent bouts of meningitis, had a large encephalocele in the nose, easy to do with a small defect. That was repaired very well. It could have been repaired from above, too. But in this case, not hard to do from below with a good outcome. Thank you, guys. Thank you, guys. Thank you.

endoscopic endonasal surgery

transphenoidal approach

pituitary tumors

proper exposure

endoscope

pseudocapsule

long-term remission