I'm going to go over some anterolateral skull base approaches, and particularly what we're going to do in the lab this afternoon. And then Franco is going to expand on that as well. So I don't have any disclosures. And most of the pictures I'm going to show you today, if you're interested, are from these two books, the Two and Van Loveren atlases. I did my fellowship with Dr. Two back in 1997. And there you can see it. That was the end of my fellowship. You see how happy he is that I'm leaving town. You see how enthusiastic I look. Not the empty, broken shell of a man that you see before you today. And this is Tanya Hines, who's the artist who drew most of these pictures. She's just an incredible artist. You can show her this bloody video, and she would make these fantastic drawings that you'll get to see today. And what we're going to talk about is frontotemporal craniotomy, orbital optic osteotomy, anterior clinoidectomy, and orbitozygomatic. And can I just see, how many people have done an orbitozygomatic craniotomy on a living person? So really most of you. Yeah. OK, good. So I'll go through it quite quickly. How many of you have taken the clinoid off extra-durably in a living person? Yeah, at least half. Good. OK. And so the question then becomes, so basically you know how to do it. The question becomes, who gets what? Who needs what? And I think, oh gosh, at least five to ten years ago, there was a real push that like all a-comma aneurysms needed an orbitozygomatic. I just don't personally think that's true. It's a philosophy thing. I think the standard frontotemporal craniotomy works really well for most of the things we encounter in our day-to-day practices. For instance, this tumor, this is sort of not a medial, not a lateral sphenoid wing, but I don't think you need to take off the orbital rim to take that tumor out. And of course, everybody knows how to do a tereonal or a frontotemporal craniotomy, so we won't spend any time on that. But when do you do an orbitozygomatic? Well for me personally, it's when I want to look far up, like up into the third ventricle, or when I want to look far down, like into the infratemporal fossa. And this is just an example. This is a relatively young woman I saw many years ago from a little town in Minnesota who had fatigue. Think of it as the Upper East Side, John. Think of it as just the Upper East Side. So she had some just constitutional symptoms, amazingly, which she was able to ignore, ignore, ignore, ignore. Finally, she has a seizure in the middle of the night, which wakes her husband up, and she came in. And this is what her visual field is, if you can imagine that she was functioning with just inferior temporal visual field, basically, and this is why. So she had this tumor not too uncommon from the one that Dr. Caldwell showed in that young child, so giant pituitary tumor. So to be able to look up here, I think it's helpful to have the orbitozygomatic process off, and this is just the post-operative picture now, 12 years later. She's continuing to do okay. Looks like a dog chewed it out, but actually it went pretty darn well. Yeah, it was a difficult tumor. This is another case. This is a terrible recurrent, recurrent, recurrent chordoma that to be able to dissect this and feel confident in this. Unfortunately, this patient's now died of his metastatic disease, but that was a case for me. And of course, so here's where the controversy comes in, right? So we just talked about this over lunch. So to me, this is a case for an orbitozygomatic. So when I see one of these, I think, this is how I'm going to do them. A lot of the staff, faculty would obviously do this endonasal, so on. So this is a six-year-old guy from Rochester, actually, who has this cranial pharyngeoma. And I really think I can, just for me, I sort of climb the learning curve of learning how to operate cranial pharyngeomas through a frontotemporal approach. I just can't make myself not do it. And so I think I get a good resection. I'm able to save the pituitary stock quite a lot. There's just another case, a young woman who was in veterinarian school. And you can see, interestingly, she has quite a shallow cella, right? So you get a very good look, looking up through an orbitozygomatic, coming this direction, and as well, just working along the floor. And so this is her follow-up. And once again, you can see her pituitary stock is intact. So that's looking up. What about looking down? Well, this is a two-year-old girl from a small town in Iowa. So you'd say Staten Island, for instance, right? So she's obviously got this problem here, and she's got this big tumor in her infratemporal fossa and remodeling. You can see it's really quite, I don't know if you can appreciate it, but this is the mandibular condyle, which has been all eroded, and her pterygoids have been pushed medially. And so she has this big tumor, and they did a needle box, a desmoid tumor. So to take that out, you really got to get wide around it, where they have a really high recurrence rate. So this is kind of what we did, is this FISH approach, where you got to skeletonize the facial nerve. We did an orbitozygomatic, and then you can get down. This is actually the mucosa, the nasopharynx, and then, of course, you got to fill up this hole when you're done. So we take a latissimus flap to do that. And this is her now, several years later. So the flap is a little bit, she still has a little bit of fullness, but looks a whole lot better, and so far, so good in terms of recurrence. This is another case where we really had to look down. So this is a 25-year-old guy from just north of the Twin Cities, who initially presented elsewhere at 2006. So a 19-year-old male with recurrent epistaxis should really make you think of one pathology, and that's a juvenile neuroangiofibroma, and sure enough, that's what he had. He had embolization resection elsewhere, and did just fine. Then he was kind of lost. He showed up a year and a half later with some recurrent epistaxis, and they said, well, your tumor's back, and we got to do another operation, and probably going to do it through lateral rhinotomy. And interestingly, he and his family thought that that was such a horrible undertaking, such a bad thing to go through, that they basically said, we're not going to do that, and they went home, and as best I can tell, for the next four years, he spent in his parents' basement playing Nintendo and eating Hot Pockets, like a frighteningly large amount of Hot Pockets. Like if you know how many Hot Pockets, you would stage an intervention and say, no more. Whatever the LD50 is for Hot Pockets, this guy ate it. And so then he showed up in 2012, interestingly, with just a little bit of epistaxis, but mostly pain. He was having a lot of pain, and he went into his local doctor and said, I need some stronger pain medicine, because I had this tumor, and they said, well, let's get an MRI scan. So this is what he started with in 2006, and this is a very characteristic look for a JNA in a young man, this tumor filling the nose, going up to the skull base. And I would say most people operate these now certainly endoscopic. We did a lot of them through lateral rhinotomies even earlier in my career, and that works well too. But they're pretty bloody tumors, but you embolize them, take them out, and usually patients do pretty well. But this is when he showed up back in 2008, so he clearly had recurrence, and I just point out that he had this over here, going all the way over to foramen ovale, which changes the landscape a little bit. And then this is what he showed up with in 2012. So that's a problem. That's a bad problem. And as you recall, the thought of a lateral rhinotomy was just too overwhelming for Haina's family to... So my ENT partner called me and said, you got to come see this guy, we got to figure this out. And of course, I was just indignant, how could this guy let this happen? No, we've got to go through all this. And I was going to run in there and say, we're going to saw your head open and take this thing out. And they're like, no, no, no, maybe you better not talk to him, maybe you just better... Maybe I'll talk to him and you can meet him after he's under anesthesia. So that's the extent. And then I made the mistake of saying, well, we better get an angiogram. That's just the internal injection. Of course, they'd already embolized the external with the first operation, taking most of the external. So it's fed mainly by the internal carotid. You can see it elevating the MCA. So I mean, you really need exposure to get control of this. And so what I did is an orbital zygomatic, I think, was very important to be able to look down into the infratemporal fossa as well as to look up to the high extent of the tumor. I actually exposed his carotid in the neck because I thought if things go really bad. We did a balloon occlusion test, which he thankfully passed. I said, you know, maybe I'll just have to take his carotid if we can't get the bleeding stopped. Then we did a lateral rhinotomy, medial maxillectomy, and then I used fasciae latae and fat from his leg. It takes about 14 hours. And I was saying to somebody earlier, as we were really struggling, I mean really struggling, lots of blood loss, we ended up losing 20 units during this case. And the resident, Jeff Jacob, who was working with me said, you know, maybe we should use the aqua mantis. I don't know if any of you have used that before. I'd never even heard of it, but let me tell you, I think it saved this patient's life because I could not stay ahead of the bleeding. And we took it out and I just saw him back in October. So I'm worried. He might have a little bit of tumor yet in his cavernous sinus. I don't think this is tumor here. That's just packing or just granulation. But I'm worried about right there. So we're just following him. But he's doing well. And this is what all that looks like. So this is pre-op. And you can see what happens if you don't reconstruct the maxillectomy defect. You see how this eye is depressed and he's got a little enophthalmos. But the other thing I'd point out is, you know, boy, it's just heresy now to talk about doing a lateral rhinotomy on somebody, right? But you can see it heals very well. It's not a disfiguring thing at all. Yeah, I don't know if you've rubbed Hot Pockets on there. You know, the other thing I noticed is, that's the same t-shirt. Isn't that incredible? He's a good guy. He's a good guy. I like that guy. So I'm just going to quickly go through how I do an orbital zygomatic. And this is what we want you to do in the lab this afternoon when we go downstairs. So there's lots of ways to do it. You can do a one piece or a two piece. Some people actually talk about doing a three piece. And the issue is whether or not you need to leave the masseter attached to the zygomatic arch. So a lot of people think that that is important. Otherwise, they get more TMJ dysfunction. So the true one piece where you take it all out and then put it on the back table and take a picture of it and show it at the meetings, I don't think many people do that anymore because you don't want to detach that zygomatic arch from the masseter. And I'll just kind of show you that. So Juan Carlos went through this. I'm going to just go through it very quickly. The interfacial dissection is very important because you don't want to get a frontalis palsy. You expose the orbital rim body arch of the zygoma. You do a frontotemporal craniotomy like you're all used to. But you have to do a true McCarty burr hole. Does anybody know who McCarty was? That was McCartney. So Colin McCarty was chairman in neurosurgery at the Mayo Clinic and he described the McCarty burr hole for taking out orbital meningiomas. So it's a burr hole that exposes the frontal dura and the periorbita. There's five bone cuts and I'll just go through those real quick. So you start out with your standard incision. You do a frontotemporal craniotomy with this burr hole exposing some of the periorbita. If you don't get it, if you just do a frontotemporal craniotomy, well you can always drill down the sphenoid wing and expose the periorbita so it's not that important. But you've got to have this exposed to do an orbital zygomatic. So this is what you start with. And then these are your cuts basically. And I, so this is just the orbital part of the burr hole. I don't try and go all the way back to the superior orbital fissure. I don't care frankly about leaving orbital rim, or excuse me, orbital roof. I've never reconstructed an orbital roof in literally hundreds and hundreds of these types of craniotomies and I've never had a patient get a problem with that. Sometimes they have some pulsatile enophthalmos to start but it always goes away. So the first cut is just across the orbital rim. The second cut is across the roof of the orbit, which is parenthetically why I do a two piece. Because if you do a one piece, you just bring this cut and you stop here. And then you've got to blindly cut across this roof with your bone flap still here. So you put the frontal lobe at a bit of risk and the orbit at a bit of risk. So I think it's better to do it as a two piece personally. And what I really do is I make this all in one cut. I just take the foot plate on the spiral bit, so what we used to call the B1. And I just cut across the rim and then over to the roof to this orbital part of the keyhole. And then I bring the foot plate in from this side. So the foot plate is sitting in here and you just cut straight down until you reach the inferior orbital fissure and you'll get your drill back. And then that's that cut. And then this is, though, you might say the hard cut or the important cut, is you have to dissect the periorbital off with a Penfield 4 until you fall into the inferior orbital fissure. It'll just fall in there. There's nothing in there that you're going to hurt. And then you take the foot plate and stick the foot plate in here and then cut up and across the body of the zygoma. And that's what it looks like. So you have this kind of protecting the orbit. And then you put this in and cut across. And then, of course, the fifth cut is just across the root of the zygoma. When you make this cut, at first you may be quite tempted to try and cut this flush with the squamous temporal bone, but you'll cut right into the TMJ if you do that. So you kind of want to cut up or away from the squamous temporal bone. And then I leave this attached to the masseter. I wrap it in a basset trace and soak sponge and fish hook it out of the way and just leave it there for the whole case. And then basically what that allows you is you can take off the squamous temporal bone flush with the floor. You can take off the lesser wing of the sphenoid in about 2 and 1 half minutes instead of tediously drilling it. And of course, you can modify this if you want to get fancy. So you can just do the temporal part and take off the arch of the zygoma if you have something like a mainly middle fossa pathology like this chondrosarcoma. You can just do the frontal temporal craniotomy and take off the orbital part if you have something like a frontal orbital meningioma. You can just take off the body and arch of the zygoma and leave the orbital rim up here if you're primarily working in the front of the middle fossa. This is a case I did just this week, actually. This is a woman originally from Cameroon who now lives in North Dakota, if you can imagine, like how unfair she must think life is. So she escaped kind of not a pleasant life in Cameroon and ended up in North Dakota. So anyway, she had this funny exostosis that was discovered in 2006 when she started to have some jaw pain. And the oral maxillofacial surgeons talked to her about taking that out. But she said, well, it's not that bad. It really grew and she got a lot more trouble opening her mouth in pain. So this is how we, you know, so just a linear incision. This is the TMJ here that the OMF guys exposed. We made a, we just cut the zygomatic arch here and then pushed it down with the masseter. And then we could work in here and just disconnect it from the TMJ here and take it out. And then that's just the reconstruction. It's pretty simple, just a zygomatic osteotomy to get to the infratemporal fossa. Of course, if you want to be really sexy, you can do it all as one, like I say. But I don't, but then this cut across here is kind of blind. I don't think that's so good. The important thing about this slide is when you put this back on, you really have to get a plate across here, across the body of the zygoma, especially if you've left the masseter here. Masseter is a very strong muscle. If you don't do that, every time they chew, this will rock and it'll cause pain. And I'll tell you, coming back a month or three months later to do this is not very much fun. So you really want to do it the first time around. And I just want to say a couple words about doing an anterior clinoidectomy. And I think Juan Carlos reviewed that quite well, so I'm going to go quite quickly. But for a tumor like this, I don't see any point in taking off the orbital rim or the body of the zygoma. You're really working in the lesser wing of the sphenoid, so you can do a frontotemporal craniotomy and then basically drill out all that hyperostatic bone down to the periorbita. Sometimes you can take it out with a ronjour. And then you can just bite off that lateral wall over the cavernous sinus. And then you're left with this clinoid here. And then I always bring in the microscope at this point. A lot of people do take off the clinoid without using the microscope, but I think it's helpful. Because there's three things that hold the clinoid into the head. The lesser wing of the sphenoid here, which you've removed, the roof of the optic canal, which is this, and the optic strut, which of course is underneath the optic nerve. So the next step after you've taken off the lesser wing of the sphenoid is to unroof the optic nerve with a diamond drill, lots of irrigation. And as Juan Carlos mentioned, that meningo orbital band you can cut, and Sebastian Froelich wrote a very nice paper about that. There's the reference there. So basically, you know, the nerves are down much and fairly, so you can cut this and peel this back, which gives you a much better view of the clinoid. And then you can hollow out the clinoid and kind of take it out piecemeal. Of course, be careful, because as we just saw, the carotid is deep in there. You can't just go to town with the drill and plunge it in there. You can get a bad surprise. And when you do that, of course, you've got to be thinking about, does this patient have a pneumatized clinoid? And this is the biggest one I've ever seen. So this woman had this very, you know, certainly resectable meningioma here, but look at her clinoid. This is big pneumatized. You can see how far out the sphenoid sinus went. So you know, if you drill in the anterolateral triangle even, I think you'd end up in the sphenoid sinus. But as long as you know this is here, it's OK. If you don't know it's there, these are the patients who literally leak CSF before they get out of the operating room. I mean, this is a hole at the bottom of a big funnel. So all you have to do is you just got to know it and plug it, and it's not hard. And you don't have to try and strip all the mucose out or completely fill this entire sphenoid sinus. You just got to plug the opening. This is that case six years later. And so this is what we want you to see today in the lab, is we'll do an orbital, a two-piece orbital zygomatic, take off the bone, decompress, frame in rotundum, and then you start to peel the dura back. And there's a variety of ways you can do this. This is kind of the, we call it the Hakuba technique. I don't know if Dr. Hakuba really was the first to describe it, but he's the one who made it make sense, I'd say. So there's the maxillary strut, V2. So you can kind of peel this dura back. You can peel it up off of V3 and connect the dots. The other way you can do it is what I call the DeLenz approach, which is you actually make an incision along the sylveon fissure, and then at this meningo periorbital band, you tee it. And that gets you looking down at the optical carotid cistern. That's the clinoidal segment. And a lot of atlases, including the one that my boss Fred Meyer has and Dr. Tu's atlas, talk about cutting the distal dural ring over the carotid. And I would say, don't do that. The distal dural ring is part of the adventitia of the carotid. So you can trim it. You can trim it over here, and you can trim it over here, but you really can't get a beaver blade under there and cut it, or you're really running the risk of seeing the inside of the artery. And then what DeLenz described is cutting the oculomotor trigone, and you can do that for about 7 or 8 millimeters, but then the fourth nerve actually crosses over the third nerve. So if you keep going, you will actually cut right across the fourth nerve right here. But this is what we want you to be able to see today. When you take the clinoid out, you'll see the clinoidal segment. You'll see the distal dural ring. This is the approach, frankly, I would use for that third case that Dr. Jane showed of that meningioma, is then you can open the falciform ligament. You can drill here. You'll get into likely an ethmoid or even the sphenoid sinus, so you've got to know that. But then you can even open up the dura on this side as well. You can see the ophthalmic artery. You can see 3 and 4 in the lateral wall here. So I'll stop there and let Franco talk.

anterolateral skull base approaches

frontotemporal craniotomy

anterior clinoidectomy

orbitozygomatic approaches

reconstruction after surgery

fourth nerve preservation