Transcript

- Dear friends and colleagues, thank you for joining us, for another session of the Virtual Operating Room. Today, our guest is Dr. Dan Kelly, from Pacific Neuroscience Institute. He's the founder, as well as the director of the Pacific Neuroscience Institute. He's truly a master surgeon, I've worked with him in the past, and I can tell you directly that his technical expertise within the skull base, and including the parasellar area is second to none. Dan is not only a master surgeon, but truly an innovator, an entrepreneur who has really established an incredible center of excellence at Pacific Neuroscience Institute, not only in neurosurgery, but other areas of neurosciences. Today, Dan will be talking to us about Resection of Tuberculum Sellae Meningiomas, either through endoscopic or minimally invasive approaches. He's internationally known for refinement and innovation in minimally invasive and endoscopic skull-based surgery. Dan, thank you for being with us, and I very much look forward to learning from your lecture today. Please go ahead.

- Thanks Aaron, and I really appreciate the opportunity to talk to you and the group. I want to say hats off to this amazing effort with the Neurosurgical Atlas. It's an incredible educational tool. I've looked through a bunch of the presentations so far, and I think it's really an incredible collection. So, I'm going to talk to you today, about tuberculum sellae meningiomas and our approach, and I want to thank my colleagues, particularly Dr. Barkhoudarian, Dr. Griffiths, Dr. Krauss, and our former fellow Jai Thakur, and our students, RJ and Alex. Coming to you from Santa Monica, California. Hopefully, you all can come visit at some point post COVID. So, tuberculum sellae meningioma is as we all know, present most commonly with vision loss, they're predominantly in women. In our experience, 80 to 90% are in women. They often invade the optic canals and they often expand, and deepen the sella. And really in discussing tuberculum sellae meningioma, this is really where applied anatomy comes into place, and the neurosurgical techniques that we employ. And it's really about applied anatomy, applied physiology, and of course, applied pathophysiology, and trying to determine what is really the best approach for removing these tumors. Some of which can be quite small, as shown here, and quite large, as shown as shown here. And so, we have to have versatile minimally invasive approaches to do the best for our patients. There's been a lot published on the approach to tuberculum sellae meningioma, both through the transcranial route and the endonasal route. We were actually the first, I think, to publish on the endonasal versus the supraorbital keyhole approach, back over a decade ago. And there've been many large series of traditional transcranial approaches and some comparison to the endonasal approach in this era of endoscopic skull based surgery. So again, with this concept of applied anatomy, when we look at the different types of tubercular meningiomas we, in trying to decide the best approach, we want to look at several things, the depth of the sellae, the laterality of the tumor, the invasiveness of the tumor. And as we can see here, in these examples, one of the things that's very common with tuberculosis sellae meningiomas is that they tend to deepen the sellae here, as you can see here, and this really allows an endonasal endoscopic approach. Here's another one with a relatively deep sellae, and the middle image here, this is a case where you could go in either approach. This particular image here, is a really a tuberculum and clinoidal meningioma, which I'll show you the video. And this is pushing the optic nerve medially, and in such a case an endonasal approach would really not be indicated, and this is a perfect case for a supraorbital approach. And then finally, we can have these larger tumors with a significant lateral extension, and these again, are also sizeable tumors in which a supraorbital or transcranial approach of your choice would be recommended. So, when we think about the approach again, I think it's very critical to consider the optic apparatus and the chiasm, and as we can see here in this drawing for most of the craniopharyngiomas, for example, we will use an endonasal endoscopic approach because the tumors are retrochiasmal, and the long axis of the tumor is along the nasal corridor. The supraorbital route on the other hand is one in which your trajectory is down the, essentially down the barrel of the ipsilateral optic nerve, and you're coming at about 90 degrees to the contralateral optic nerve, as you can see here, the chiasm and the two optic nerves. We often will use the mini-pterional approach for things that are more lateral, and lower in the middle fossae, and this is a good, another good approach to some parasellar lesions. So, I'm going to show some case examples now, of tuberculum sellae meningiomas that we approach from below. And then, I'm going to show some from above, and then I'm going to give a summary of our outcomes, but also suffice it to say that over time, we have transitioned to doing more and more of these through the nose, and I think part of that's more comfort with our endoscopic approach, more precision and better outcomes with the skull based repair, and a lower CSF leak rate using nasal septal flaps, and a better ability to decompress the optic canals bilaterally with the endoscopic endonasal approach, more so than with the supraorbital approach. So, the first case I'm gonna show you is a 46 year old woman with vision loss for approximately a year, and she came to us with minimal light perception in the left eye and decreasing vision in the right eye, headaches, Amenorrhea, and she had this sellar mass, and she had a mild prolactin elevation. And when we saw her, this was her exam here, 20 over 400 in the right eye, no light perception in the left, other cranial nerves were intact. And she came in with this scan here, and you can see a classic tuberculum sellae meningioma. You can see the distinction between the pituitary gland below the tumor and the bright enhancement, which lets you know, that if it's enhancing more than the pituitary gland you're almost certainly dealing with a meningioma, here's the axial view. This is showing, this is a coronal T2 view showing the invasion of the tumor out through the left optic canal, here. And you can see another T2 and what is a, and maybe we could move my image there. What's really impressive with this patient's profile was that in fact, she was pregnant and she didn't know she was pregnant, and her prolactin level, you can see of 119, but her HCG screen was positive. And we do know that in pregnancy that meningiomas can grow in women, and we recently wrote a paper about this, but this is a nice example of a meningioma progressing during a woman's pregnancy. So here, I'm going to show the video now of this approach and because she had the optic canal invasion, really bilaterally, we did an endonasal approach. So this is a, we've already raised a nasal septal flap. You're looking at the pituitary gland, here. We're working over the pituitary gland here, we're using the Doppler frequently. And this tumor was quite a rubbery and firm tumor. We're again, trying to elevate it away from the pituitary gland, knowing full well that this woman is pregnant and she needs her gland and her infundibulum to be intact. You can see that we've come over the top of the tumor now, and we're starting to see the optic chiasm and the anterior cerebral complex and generally dissecting the tumor. And again, separating, fortunately in most tuberculum sellae meningiomas, there is an arachnoid plane that will separate the tumor from the optic apparatus, and an arachnoid layer that protects the infundibulum. And so you can see, we're using a 30 degree endoscope here, and we're slowly working over towards the left side, where there is a greater degree of optic canal invasion. This is at the closure here, we're putting a fat graft in above the gland to fill the dead space. And then, we will put a layer of collagen and bone over that. This is our standard repair, and I'll note, we do not use lumbar drains for any of these cases. We stopped using them about eight years ago. So, there's the bone that's going in from, that was harvested from the septum, and then the nasal septal flap is laid into place. And then we reinforce that with collagen sponge tissue glue, and this precision placement of the Merocel tampons, for these cases we do two, Dr. Griffiths places them so that patients can actually breathe around them, and they do quite well with that. So, we can go now to the next slide. So, this is showing the repair. We always get a CT scan immediately after, because you want to be able to see the degree of air, if any, and see the fat graft placement and see the bone placement. And you can see here, that there's a bone flap in place, fat graft, you can see the Merocel. And on the Post-OP Day one MRI you can see again, the fat graft and the Merocel. And then again, you can see that again, a generous fat graft. There is still some elevation of the optic chiasm, but this patient, and notably, because she was pregnant, we did not give gadolinium, but you can see, it appears to be a gross-total tumor removal. She did have late onset DI, which subsequently resolved. She had marked improvement in her visual fields and visual acuity. And you can see here at six months out, after the successful delivery, you can see this with a gross total tumor removal. And here she is with her baby, and with Dr. Griffiths holding the baby. So, that's a really a nice outcome. So here's another case of a woman, 60 years old who presented with decreased vision for about eight months, we've done the approach. And really this is a, in some ways like a convexity meningioma, and we have to take the dural base there, again, working over the top of the pituitary gland. The initial internal debulking. And then, as you reach the tumor interface with the gland, you can see the infundibulum there, because this was such a fibrous tumor, we use the NICO, or we use the ultrasonic aspirator. You'll see, there's a nice view of the infundibulum, and it's always there with the tuberculum meningioma, it's always at the back here, and I think this is an important thing to see on this image, here. You can see the infundibulum coming down, and you can anticipate where it's going to be. So in this woman, again, very fibrous tumor dealing with the anterior cerebral complex and essentially just chipping away at the tumor here, little by little, copious irrigation, sharp dissection, not pulling too hard, preserving the arachnoid and the chiasm, and this was this part of the tumor was extremely stuck to the ACom area. And we achieved really a gross total removal with the exception of, maybe a little bit stuck on the vessel which we cauterized here. We thinned down with the NICO. You can see her chiasm, well decompressed here, and at some point you would have to say, this is enough and not try to go too far and have a vascular injury here. There's the infundibulum, pituitary gland intact. Again, fat graft collagen bone, all natural with a nasal septal flap. We do not use anything synthetic, in these cases glue, and there's the outcome. We can, let's see, let's go to the next. So, yeah, so here she is post-op again, large fat graft. You can see that the infundibulum and the gland are enhancing very nicely. Nasal septal flap is enhancing, not as robustly as some, but she ended up doing very well. She, here she is at five months post-op, now as most of you know, these fat grafts resorb, in her case, her fat graft did not resorb, And very interestingly, not only at five months, but at almost five years, she still has this sizeable fat graft, but she's doing well. She's had no recurrence, this little area of tumor we thought we might've left behind on the ACom has showed, on the cerebral complex, has showed no sign of coming back. So, she's doing very well, and so far so good. Now, here's a very challenging tumor. This is a recent case that we did, and I would have you all think about how would you approach this. And there's some very critical issues to think about. So this is a 39 year old man with progressive left eye vision loss, and you can see that he does not have a deep sellar. The sellar in fact is very flat. He has a fairly wide tumor. He has bilateral optic canal invasion, and he's got an extremely calcified tumor, and certainly that can give anyone pause to do this through the nose, but it's an important consideration in looking at this and thinking about it, nonetheless, we thought given the bilateral optic canal invasion, that's his presentation. The best we can do for his optic nerves is coming through the nose. So, that's what we chose to do. And, here is the procedure. You can play that video. So Dr. Griffiths here is raising the nasal septal flap on the right side, and obviously this is critical to a good skull-based reconstruction given that this is all gonna go. No, you can see we're starting the approach, doing a wide opening, and doing a bilateral optic canal decompression, copious irrigation with the drill. The tumor is already seen to be eroding, through the dura, here. Very important to expose the medial OCRs, important to use the Doppler frequently. And really this is such a critical part of the operation. You can see here, this is part of this calcified nature of the tumor coming through the dura here. Already, we know we're going to have our hands full with this case, but again, careful wide bony opening. And here we can see the finished product, with the bilateral optic canals exposed. And now we're starting that opening, and again, using sharp dissection to initially open, finding the top of the pituitary gland. And you can see this as an entire calcified mass here of the tumor. We often will incise the gland, to give us a little more room inferiorly, and that does not hurt the gland if you do it not too aggressively and not too deeply, but you can see this entire mass is moving and you have to know that of course they're stuck, this tumor mass is stuck onto the optic apparatus. So, this was a painstaking removal here. Now we can see the infundibulum. We have a nice view of the infundibulum right here, starting to see it right there, going up. And then, here the ultrasonic aspirator was extremely helpful. I'm not sure we would've been able to do this case, without it. We chipped away at the tumor, put it on a very high setting, and once we got out of this calcified core, the tumor was in fact rather soft, but you can see here, the infundibulum again, and taking care of not to put too much stress on that, nor on the superior hypophyseal vessels. There's a pecan there, and you'll see the superior hypophyseals coming in, right here, there's one, there's another one. A leash of them here and these have to be preserved, and so now what we've done is amputate the bottom of the tumor, and gotten this out, we know exactly where the infundibulum is, we can see it ascending up behind and under the chiasm, and now we have to deal with sort of the mushroom cap of the tumor, at the top here. And again, of course it is largely calcified as well. First, we should see the anterior cerebral complex here. And again, just careful methodical dissection. This large mass is finally freed up, and fortunately the top part of the tumor was not as stuck to the brain and came away a little bit more easily then the lower part. And then again, working on both optic canals and trying to bring this tumor out with careful dissection, and using the angled endoscopes here. Now, this is showing you the left optic canal decompression, here we've opened the left optic canal. You could see the optic nerve coming out there. This was really the final look, there's the carotid down below, right there. And you can see the right carotid, the left carotid, the gland intact, and what appears to be a gross total removal, same closure, fat collagen bone, and nasal septal flap, and then the Merocel tampons for any little belt and suspenders approach, so that there's no migration of the repair construct. Next. And this is the post-op, again, a large fat graft. I was not entirely happy with this bone graft. You can see it's a little lower than the planum, and you can see the fat is a little bit out into the top of the sphenoid. You can see the gland here very clearly, and you can see though that the tumor that was out, going out both optic canals is gone, and a nicely enhancing pituitary gland. The patient did, well, let me go back. The patient did very well, and had no postoperative leak again, no lumbar drain. We don't use lumbar drains in these cases, and I don't think they're necessary with this reconstruction protocol. So those are several endonasal cases there. So now let's talk about the supraorbital route. And I like to consider it as the "sweet spot" of the frontal temporal craniotomy, and it really allows a retractorless entry into the floor of the frontal fossae, and exposure of that area, the parasellar area, and the peri-sylvian areas. And it's view has certainly expanded with endoscopy, and we would encourage you all to use endoscopy. And when you think about the pterional craniotomy, this, the supraorbital is really a modification of that and a minimization of that. And when you combine that with the minipterional approach, you have two nice approaches that can be chosen one over the other for certain pathologies, and so we don't use the pterional craniotomy, we use the smaller minipterional, in some instances, but in fact, as I'll show you, we use the supraorbital approach much more frequently, about five to one of the supraorbital versus the minipterional. This is just a, actually a heat map of a manuscript we're working on showing our use over 13 years of the supraorbital versus the minipterional, and you can see that, I think data speaks for itself, about which approach you might use. And this is both intra axial and extra axial tumors, but just to show you the variety and locations and what you can do with these two different approaches. The supraorbital route is really an nice route to get you to many places from meningiomas, not only tuberculum sellae, but more that extend out on the planum, clinoidal meningiomas and some olfactory groove meningiomas, and even some that extend fairly high up onto the convexity, here. So a very versatile approach. The positioning is similar to a pterional craniotomy. We'd like to have the monitors in place and ready to move in for endoscopic assistance. But most of the procedure itself is done with the microscope, and then the endoscope is brought in. And this is a drawing from a recent publication on how we do the approach and some of the key anatomical landmarks, including the supraorbital nerve and notch here, the placement of the craniotomy, and the initial burr hole, and the incision. And so, I'm just going to go through a little bit of this. Basically, the incision is right through the middle of the eyebrow, and the craniotomy should be as tall as possible, after placement of the burr hole. It has to be at least two centimeters high, otherwise it can be a very difficult to use your instruments, particularly the bipolar. And you want to try to preserve the supraorbital nerve, as you can see here, and very little temporalis muscle and fascia have to be opened and removed. One question that comes up frequently is, "What about a big frontal sinus?" And in our opinion, it is not a contraindication, but you do have to prep for an abdominal fat graft. So, in this case, of this patient with a meningioma here, you can see that this is a large opening into the frontal sinus here, and this is simply filled with fat at the closure, and you can see the fat on the post-op scan here, and a nice cosmetic outcome. So, the key anatomical landmarks, again, the supraorbital notch and nerve, the frontal zygomatic suture, and then these branches of the facial nerve, here, again, showing the incision, literally through the thick, main thickness of the eyebrow like this, you have to get below the superior temporal line. If you don't get below the superior temporal line, you won't be able to place your burr hole. We take these skin incisions slightly past the supraorbital notch, but then we have to dissect out the nerve. And this is just showing again, some anatomical dissections from Dr. Rothon and team, showing these multiple branches of the facial nerve coming up, and we have actually changed our approach on this, making a more parallel incision to these and not going up as high. The original incision that we did was more of an arching incision like this, for the pericranial flap, but now we do this incision and then we tee it up straight along the nerve, and this preserves some of these multiple branches and has a likely, and reduces the risk of a frontalis palsy. There's just the exposure again. So, I'm going to show you a case here. We can play the video. So, this is a small clinoidal meningioma, in a woman with progressive vision loss and with the optic nerve pushed medially, as you can see here, so you could not do this safely through an eyebrow. So, here we're showing you the supraorbital nerve, the left supraorbital nerve, and we're protecting it and then we're making this pericranial cut, right here. We've already gone through orbicularis oculi. So there, you can see the superior temporal line and you can see the nerve branches, and then the single burr hole, and then the craniotomy is turned. Very important, to drill down the floor of the frontal fossae here, so that you have a big flush opening into the frontal fossa. You can see we're starting simply with the microscope here. Again, this is a small tumor, but really distorting the left optic nerve. So we're opening the arachnoid and we place a gel foam in the optical carotid cistern, to avoid getting all that blood there into the cistern. And then we start to remove the tumor, and fortunately the tumor, at least in this area is fairly soft. And you can begin to see the nerve here, the left optic nerve. And you can see that with the supraorbital approach, even though it's a relatively small opening, we often have three instruments in, sometimes four, it's very easy to have an assistant helping, through the corridor, using a keyhole instruments. So here, you can see we're now really starting to see the nerve and the optic tract, and we can see the super clinoid carotid artery here. And we can begin to see that the, now with the endoscope, we can clearly see the distortion of the left nerve. You can see the chiasm and the contralateral optic nerve over here, but you notice that with the 30 degree endoscope, we get this beautiful view of the attachment of the tumor to the nerve. And it was my impression that we were not going to be able to completely remove this without injuring the nerve. We did leave some tumor on, and we fully explained to the patient that she would likely need a stereotactic radiotherapy. Now, the closure here is very important. Well, I'll get to that, but basically the closure is done in a very meticulous way to provide for a good cosmetic outcome. Okay, let's go to the next. So, here is her immediate post-op day one MRI, and you can see no obvious residual tumor. This is her about, I don't know, this is maybe three months out and you can see the healing of her eyebrow and a really nice cosmetic result. This is a patient from many years ago, actually, who had another pregnant woman with twins and progressive vision loss, again, a pregnancy associated meningioma resulting in rapid vision loss, in her case, because of a poorly pneumatized sphenoid, and also this was early in our endoscopic time. We did this through an eyebrow. Also the width of the tumor is shown here. It may have been difficult, to get a good resection endonasally. So this is two years after removal, complete removal. We just saw her not too long ago, she's now 12 years out. Her twin boys are doing great. And so, a complete removal, and no recurrence and recovery of vision, a significant recovery of vision. And then this is a tuberculum posterior planum meningioma, here. As you can see, this touches, this is partly on the tuberculum here, going into the sellar. And this is a case again, from a few years ago, going through the right side. And again, you notice no retractors, three hands often in the operative site, and the debulking of the tumor here is a fairly old video, but again, making the point that these tumors are exceedingly approachable through this approach. And now bringing in the endoscope, and seeing the optic apparatus here, this is the right optic nerve and the chiasm, you can see the chiasm arching over this way, and now we're using a 30 degree endoscope and a ring curette to scrape tumor away from the tuberculum. One olfactory nerve was sacrifice, which is often the case coming from this direction. But again, you can see with this approach, because you start on the floor of the frontal fossa, the brain usually looks pristine, and there's just no need for a retraction. Next. This is post-op day one, he's now more than five years out and doing exceedingly well, no evidence of a recurrence. And just to make the point that you can remove quite large tumors through the eyebrow. This was approach that I did with Dr. Barkhoudarian, and you can see that a gross total removal, and this was a case in which we didn't use the endoscope because the tumor was so large. We had such a large cavity in removing this posterior planum meningioma, and we preserved olfaction. Now, here's an example of another case. This is more of a true olfactory groove, a little more interior, and this is important in the decision-making process of, you know, some people would say, well, you could do this through the nose and endonasally, endoscopic. The problem with that is, in a person with normal olfaction, which she had, as you can see from her olfaction score, you really guarantee Anosmia. So, in my opinion, that is not a viable approach given how much people prefer to keep their sense of smell. So, when you're looking at this to decide, which way could we go, if you, now, you could certainly do bicoronal, you can do a pterional. We did this through an eyebrow, and then the question is which side, the important point here is that she has a little bit of edema here in the brain. She also has tumor that is extending deeper on the left than the right, which would suggest that the right olfactory nerve is in better shape, and likely more preservable. So in that case, we would come from the left because we know that if we come, the side that we come from with a large tumor like this, we're going to have a very hard time saving that ipsilateral olfactory nerve. So here's the video, and we've already started again, we're coming from the left side, and we've drained the cistern. And we are starting to dissect the tumor here away from the frontal lobe. And, you know, this is a very large tumor there, we're opening up the cistern again, and starting to dissect the tumor away. And then internally de-bulk the tumor. And of course, using standard microsurgical technique with the ultrasonic aspirator, three hand technique here, you can see, this is a very useful approach for meningioma, skewering the meningioma with an instrument to pull it away from the brain, and that then allows it to be shaved away in progressive fashion either with micro scissors or the ultrasonic aspirator, and with a tumor of this size, this just needs to be done, repeatedly cauterizing the base of the tumor, the blood supply. And again, once you create room, then again, doing the same process again and again, in an iterative way. And here, we're starting to see the falx here and we're continuing to debulk the tumor. We eventually, will see the tumor that's going under the tentorium, sorry, under the falx, here. And this, in a similar fashion is brought down and with nerve hooks. And then eventually of course, we need to open the falx and remove part of it. And here, we're expecting to see the left olfactory nerve, I'm sorry, the right olfactory nerve come into view here. And this is where one needs to be extremely careful, as you reached this point in the case, the left olfactory nerve was sacrificed. And now, we're seeing the contralateral frontal lobe, here. And again, shaving down this very large tumor bit by bit, and then shortly here, I promise you will be able to see the right olfactory nerve. Just further decompression of the tumor, taking it down bit by bit. Fortunately, it was not too stuck to the brain on the contralateral side. You can see preserved plain on the contralateral frontal lobe, here. And then finally further dissecting in this posterior, sort of, lateral corner of the tumor. Now, this in fact is the, this is the left olfactory nerve here, and a key, small branch that we're preserving, here. And again, just taking our time, that is the stump, of the left olfactory nerve, which we knew we would need to sacrifice. And again, three hand technique, very important, copious irrigation, taking the blood supply away, cauterizing the falx further. Sorry, This video is a little bit long. I may have used a less edited version here, but again, showing the long process here, and cauterizing the falx and the attachment, this then allows us to see the right olfactory nerve here, which we are preserving all the way out to the cribriform, and you'll see, we bring in the endoscope here, for a final view. You can see the olfactory here. And now with the endoscope, with a 30 degree endoscope, again, we can see the olfactory nerve preserved, and then a final look and again, a complete removal with preservation of the contralateral olfactory. And I think this, the endoscopic assistance is really key here, to allow you to do that. I think we can go to the next image. And this is her post-op day one scan, and she has been doing well and she has preserved olfaction. So again, a large olfactory groove meningioma, it's able to do olfaction sparing with its approach, but endoscopy is really key. So, this is a paper we recently published, sort of a technical note on the eyebrow approach, and just to make the point again on cosmesis here, you can see that we really do have nice cosmetic outcomes, and this is very doable. We have one patient with a sort of a suboptimal outcome, and you do have to be very careful and meticulous, in this closure here. In some cases, you may see some settling of the bone or temporalis muscle atrophy, and we do fill in the gap below the eyebrow with bone cement, now. So, I'm going to end with this last video that is, I showed these two cases at the beginning of a smaller tuberculum meningioma, in a 52 year old woman, and then a much larger one in a 43 year old woman. And in the smaller one, because of its size and the left optic canal invasion, we went through the nose. And in this larger one, actually with some degree of bilateral invasion, but a much larger tumor, we went supraorbital. We can play that video now. So, here we can see these two cases, and compare and contrast them, mark the difference in size. I'm going to show you first, the smaller tumor, and what's most important here is this degree of optic canal invasion that you can see on the left, and which is for us a clear indication to go through the nose. And you'll see in the video here that this allows us a really nice way to decompress the optic canal. So, here we're harvesting a nasal septal flap and bone, putting the flap in the nasal pharynx, harvesting the keel of the sphenoid, for closure, and then doing the exposure. And again, with the focus of the left optic canal, decompression here, that's really the goal of the initial exposure. We don't need to decompress the right up to canal, and you can see this nice a decompression there pretty far out, along the left optic canal, using the Doppler prior to opening the dura. Very important to keep the blood out of sphenoid. So you have a good endoscopic view, you notice we don't allow much blood to accumulate around in the sphenoid, we irrigate frequently, and I think that really improves your image quality and improves your videos, for that matter. Here, we're taking the belly of the tumor out, just cutting away this dura sharply through the circular sinus and exposing the top of the pituitary gland, which is down here. And we use the Kerrison sometimes to remove the dura. It seems to be a very good instrument, if you have sharp Kerrisons. So here, we're at the bottom right, and we're starting to see CSF come through as we're mobilizing the right lateral aspect of the tumor. We're getting a nice view of the right optic nerve, over here, right here. And we know that this is really the easy part of the tumor, we know the challenging part of the tumor is going to be over here, where it's going out, the optic canal. And again, sharp dissection, use the ultrasonic aspirator, use sharp dissection, perhaps the NICO. Cut these arachnoid bands sharply, and again, gentle traction, be mindful of the pituitary gland and the infundibulum, which is going to be going up like this. Those are critical, and I'm just mobilizing this tumor away from the gland. And now we're starting to come over toward the mid part of the chiasm, and the left optic nerve. And here, the tumor was very fibrous, and we just kept chipping away at it. We're using a 30 degree endoscope here and shaving it, and shaving it away little by little and hoping that it eventually cuts us a break, and allows us to really take it away cleanly from the right, I'm sorry, from the left optic nerve. You can see that we're slowly making headway here, fairly bloody tumor, and very important to irrigate frequently, and keep the blood as much as possible, out of the field so that you can see what you're doing. So, you can really start to see the top of the chiasm and left optic nerve, coming in there. And now we have this stump of tumor, that's going out the optic canal here, and very soon we're gonna be able to see the top of the carotid and the olfactory artery take off. I'll show you that in a second. Unfortunately, this was a very bloody tumor, this area was, of the tumor was bloody there. So, you can see the nerve is pretty attenuated right here, but able to be gently removed. Now, we're opening the optic canal sharply, try and get this last remnant, and there is the olfactory nerve, I'm sorry, the ophthalmic artery right here that we're very mindful of. And then really just trying to shave off this very last bit of tumor from the optic canal, and preserve the ophthalmic. And we were able to do that, we did cauterize a little bit of the tumor there, but pretty much gross total removal. You can see the infundibulum there, again, the same closure, fat, collagen, bone, and the nasal septal flap. And this is a very effective closure, doing a reverse flap, Dr. Griffiths is doing a reverse flap here to protect the exposed nasal septum. And here she is on her CT, you can see the bone here, and the fat, that's from the recovery room. And this is her day one. And this is her three month postoperative MRI, no obvious tumor, and we've actually seen her since then, and no evidence of regrowth, and improvement in her vision. So, now here's this larger tuberculum and posterior planum meningioma that Dr. Barkhourdarian and I did together. 43 year old woman, with progressive vision loss. And you can see bilateral optic canal invasion, but given the large size we decided to do this through an eyebrow approach, and you can see this is through the right eyebrow. This is the setup here, this is again, the markings of the incision. And we'll just take you through this opening again. But I think, again, this is a really nice approach, even for these large tumors, provided you take all of the necessary precautions to maximize the exposure through this relatively small opening. Here, we're exposing and preserving the nerve here, and we're doing this pericranial cut, and we're actually going beyond the nerve, and we're going to retract the nerve a little bit. Now here, we're placing the burr hole, exposing the dura, and then doing the cut. And again, you can see the supraorbital nerve here, the right supraorbital nerve being retracted and protected, and coming around and completing the bone flap. And then, very important to drill down this inner table here so that you have a very flush wide opening into the frontal fossae, and you can see here, just measuring out the height. So there, where we're just exposing the right optic. And again, no retractor, we opened the cisterns to get some relaxation, cauterizing the tumor base, and then starting to internally debulk it. And this tumor was fortunately soft and allowed us, I think, a more complete resection than we might've gotten otherwise, if it weren't soft again, here's the optical carotid cistern, and just working on slowly decompressing the tumor, both, and this is working medial to the right optic nerve. This is the contralateral optic, sorry, that was, and this is the, actually the infundibulum here. And again, progressive internal debulking here. We're working along in the tuberculum area, between the two optic nerves and trying to remove tumor from the tuberculum. And you'll see when the endoscope comes in the view that we're afforded. Now, we have not opened either falciform ligament, and we have not drilled the optic canals here. And we'll show you the, in this case, we didn't do that. So, here we come in with the endoscope and you can see the entirety of the chiasm there. And you can see with this very angled 45 degree endoscope, we're actually looking up into the optic canals and able, with a ring curette to remove tumor within both the right and the left optic canals, this is the right optic canal here with a complete removal of that tumor that was not adherent. And so very helpful, this was the closure here, and you can see we've managed to preserve the nerve. We did not get into the frontal sinus here. Some tissue glue. Actually, we did get into the frontal sinus, and we, I think we put a fat graft in there, some tissue glue, and here's the closure. This is very important, this gap is over the eyebrow, and we put that bone cement there, which really provides a very nice cosmetic effect for the patient. And this is just the final closure, but it should really be done in a meticulous way, because this is what the patient's going to see, and their friends and family are going to see, and here she is on post-op day one CT. You can, or post-op day zero CT, and the MRI with the gross total removal. And you can go to the next slide. So, here's our series. This is 33 patients, 91% women from over about a 12 year period, and you can see that we did just over 60% through the eyebrow, I'm sorry, through the nose and 39% supraorbital route. And in our original experience, that ratio was essentially flipped. And so, we've been doing more of these endonasally, and this is very important here, on the anatomical factors. If we look at all of these cases collectively, you can see that the mean tumor volume, actually, I'm gonna go back here, sorry, the mean tumor volume was significantly higher in the supraorbital approach. The mean maximal tumor diameter was higher, the degree of lateral extension was higher and the percent above the planum was higher. So the endonasal tumors had more tumor below the planum, they had a deeper sellae and they had a more acute mean tuberculum angle. And that angle is this angle here. So, the more acute, that is an indication to go through the endonasal, and that's another factor which helps us decide to go endonasal. Interestingly, the optic canal invasion was fairly similar between the two groups. And here's our extensive resection. So, if you just look at gross total resection, 80% in the endonasal versus 39% through the eyebrow, but if you look at the extent of resection, volume metric were pretty high. So, these were, you know, near total removals with a very small amount of tumor left behind, perhaps adherent to, in the optic canal or on a vessel. So, this is a pretty high extent of resection. Most importantly, I think the optic canal decompression was done much more frequently through the eyebrow than through, I'm sorry, through the nose, through the endonasal approach, than through the eyebrow. But interestingly, vision improvement was similar within the groups. We found the endoscope to be helpful in additional tumor removal in four of the 10 supraorbital cases as we showed, in that last example. And one of the points I think with the supraorbital route is that you do not need retraction, and therefore the flare changes in the brain and these sort of retraction related injuries, that you might see with a more traditional craniotomy, do not occur. We had only increased flare in one of the 13 patients. We had one MRI that was missing, but in one of the 12 patients, we had increased flare, in none of the endonasal cases, did we have increase of flare changes. In terms of other complications, we had no new hypopituitarism, and I think this is in part due to just appreciating where the gland is, being careful with the superior hypophyseals and the infundibulum. We had no DVTs, PEs, MIs or mortality. We did have one CSF leak that we had to take back. We had one case of vision decline, in the supraorbital approach, one stroke, and one hematoma. Overall, pretty decent results. This is a trend line, and this is a graph showing over in our original series, and going back to 2005 to the current series. So, a total of 45 patients, and you can see that the blue is the super orbital approach with endoscopic assistance or without, and the green is the endonasal approach. And you can really see the trend here, that we've really been doing the majority of these now, particularly in the last decade through the endoscopic endonasal route, if these certain factors are present. And so, this is really our algorithm, the factors that favor an endonasal approach with the majority, and here's some examples, the majority of the tumors below the planum, the tuberculum angle is less than 135 degrees. Again, a more acute tuberculum angle here, like in this, or this. Minimal lateral extension. Presence of a hyperostotic tuberculum, like we're seeing in some of these cases here. And with, or without menial optic canal invasion. The factors that favor the supraorbital approach is that the majority of the tumor is above the planum, you have a larger tuberculum angle, and a larger tumor with lateral extension, and no medial optic canal invasion. And then, factors for either approach. If there's similar portion of tumor above and below the planum, and there's minimal lateral extension. And so, in general, really the tiebreaker there is whether or not there's optic canal invasion. And that's really key. So, if that's present, we will do those from below. So in concluding, I would say that as time has evolved, we're doing the majority of our tuberculum sellae meningiomas through the endonasal route. The endoscopy is certainly recommended for those cases that you do from above, and I think what the appropriate experience and technology, both routes are safe and effective. And I thank you all, for your attention today.

- Thank you. Great talk Dan, very useful, great techniques, really enjoyed it.

- Thanks.

- I want to ask you to two questions. Number one is, as we all know, when we do a transcranial approach, there's always these tiny amount of tumors that trail off or tail off when you're removing the tumor on the dura, that are not accessible via endoscopic approach. So, although the endoscopic approach is extremely useful, number one, because you're approaching the sub cosmetic lesion, via sub cosmetic route, therefore the risk to the chiasm optic nerves are less, and as other suitors have demonstrated, the endoscopic grafts for a section of tuberculum sellae meningiomas has better optic nerve function outcomes at the slightly increased risk of CSF leaks. So, that's a very known fact, however, there's still some missing data, long-term, if the recurrence rate of endoscopic technique is larger because of those very tiny, thin sheets of the tumor that are inaccessible laterally via endoscopic approach. And I don't think we just have enough follow-up yet, to assess that outcome. Is that something you can comment on, please?

- Well, I think you raised a great point, and if we go back to the Simpson grading, I think it's really challenging to get a Simpson grade one removal of these meningiomas, and we don't think we do, in probably the great majority of cases. And, but we do have some fairly long-term follow-up in some of these patients, where there's no evidence of tumor coming back, and it may have been a Simpson grade two or three. We don't typically use a Simpson grading system, but I know people still like to use it. I think that time will tell, you know, I think for a benign tumor that is radio-sensitive, you know, getting 98, 99% of the tumor out, and improving a person's vision, and not trying to go too far, I think is a reasonable approach. I tend to be a little bit more conservative. We certainly don't ever give radiation to anyone, unless they show clear tumor progression. So, but I know, that some of the traditional skull based surgical crowd, they still frown on this approach. But I think, as you said, the visual outcomes, and I didn't go through the literature on this, but the visual outcomes in large series are clearly better-

- Mm hmm.

- Clearly really better with the endonasal route, and I think also the degree of, the degree of, sort of collateral damage with traditional approaches is higher, than it is, say with the eyebrow. And you can see on those flare changes, which we just, you typically don't have any. And I think that's one of the beauties of the supraorbital approach, when it's augmented with endoscopy. So I think, you know, in the short term, possibly the complication rates may be lower and the trauma to the brain may be lower, for both the supraorbital and the endonasal. But for the, you know, the endonasal, can you do a Simpson grade one? Probably not very often. Does it matter? I'm not sure. So I think time will tell, but I think this is, when you're really, if your top priority is to restore vision, I think coming from below, when you have medial optic canal invasion, unless it's a really large tumor, it should be done from below.

- I agree, in my book I think there are two lesions after pituitary tumors where endoscopic endonasal approach has demonstrated clear superiority. I don't think we approach, unless extremely rarely any pituitary adenoma through the transcranial approach. And I think the next two lesions, that have demonstrated extremely good outcomes via endoscopic endonasal approach is craniopharyngiomas, and tuberculum sellae meningiomas. They appear earlier on, in their size, growth, and they have a very safe profile and good outcomes, in terms of protecting the optic apparatus. So, I agree with you, pituitary adenoma, craniopharyngioma, tuberculum sellae meningiomas, just ideal candidates. I would say, currently instead of the art of practice, duals are best approached via endoscopic endonasal approach. I want to bring up another controversial topic. For a sizable tuberculum sellae meningioma, the minipterional approach offers certain advantages that supraorbital may not. One of those is the early clinoidectomy, early decompression of optic nerve, less manipulation of the nerve and importantly, early identification of the nerve, because then you can protect it early on, and improves the efficiency of the operation. And again, there is fair amount of controversy. There's no randomized data, to show one versus the other better, terms of supraorbital or pterional with an external clinoidectomy, but I do believe that there is certain advantage in larger tuberculum sellae meningiomas with significant compromise of vision that early clinoidectomy exdurally, will protect the nerve more. Although, I don't have data for that. Would you please comment on that?

- I think you're probably correct on that. That's not something we do very often. I don't really have much experience with it. I will tell you, I think that that's, it makes a lot of sense, you know, and I think it makes sense also, I mean, this is why doing the endonasal approach for medial optic canal invasion makes good sense, because you are able to decompress one or both optic nerves early on in the procedure. So, I think that ability to do an early decompression is certainly beneficial. And it's something that probably more of us should be doing. The minipterional approach as we do it, I think can provide some challenges in getting over to the other side, as opposed to the supraorbital, with the supraorbital, you actually have a better view of the medial optic canal, of the contralateral optic nerve because of the height with the minipterional you're lower in the middle fossae. You're kind of coming in, on the plane of the optic chiasm and nerves, you come in about at that plane. So it's a little harder to get over to the other side, and I think that to me is an issue. But if you just have one optic canal, one optic nerve that's not doing well, you probably have with the minipterional, a great exposure. So, I think that's a nice alternative.

- Right. One of the interesting, that you very well alluding to Dan is that the potential space where the tumor infiltrates for this tuberculum sellae meningiomas is the medial part of the optic canal. That is so well, important to recognize, and there's been occasional cases where I have approached the more left leaning up tuberculum sellae meningioma with a right-sided supraorbital approach or eyebrow, because the view is so much better contralaterally along the area where the tumor infiltrates through the frame, and I think that's something that should be very well, sort of recognized. Before we close this session, I want to ask a question that I often ask, from some of our other guests. You, as someone who has done a skull-based surgery for a long time, with a huge experience. What is your best advice to a young neurosurgeon, in terms of what is the keys of success in skull-based surgery, technically? Obviously some of the most important things are experienced, patients, passion for excellence, don't pull on structures unless, you know where you are, and protect the perforators, and it's best to say, "There it is," and be wrong, than say, "There it was," and be right, thousand times, we know that. So, besides those, what are your pearls of advice, if you had to restart your career.

- Mm hmm. What would you have told yourself? Please remember these few points.

- I probably would've picked up the endoscope a lot earlier. I think the endoscope's wonderful tool, and I would suggest that, and I do suggest this, that when you're doing a craniotomy for a brain tumor, use the endoscope, even if it's at the end of the case to take a look and see, because you'll be surprised what you see. I think in that last meningioma I showed that we did from above, the utility of the endoscope in sorting out where is the contralateral olfactory nerve, for example. We did a couple recent medial sphenoid wing meningiomas, and through an eyebrow, and we debated whether to do pterional or, minipterional or supraorbital, and did them both supraorbital, and we would not have been able to get the tumor completely out without the endoscope. So, I think that's one thing. I think that the getting facile with both the endoscope and the microscope is key, getting facile, working through narrow corridors, I think is key. And I think that this is, you know, endoscopic skull-based surgery is not just through the nose. It's also through the eyebrow or the minipterional. And I think the more people can work through these smaller corridors, using good neuro anesthetic techniques, good micro instrumentation and endoscopy, you can do a lot more with less. You don't need these large, big exposures, which exposed the entire brain or a big swaths of the frontal lobe or temporal lobes to the air, to the outside world, for all that time. You just, you don't need to do that. And I think it takes time and it takes patience, and I, again, as I said at the beginning, this is really about applied anatomy and applied physiology and understanding what structures are distorted by what, and understanding the breaking points of key structures like use, like you mentioned, you know, not pulling too hard on things, using sharp dissection, anticipating things, using the Doppler, that's the other thing I'll say, because I keep, I hear about these vascular injuries that occur over and over again, medicolegally sometimes. And you know, the Doppler is a lifesaver, not only for the patient, but for you from a medicolegal standpoint, it will prevent you from doing stupid things and cutting a vessel, that was just a couple of millimeters away, but you didn't know it was there because you were relying on navigation, which is no longer useful, once you've taken out half the tumor. And I think those are sorts of things, this sort of, you know, avoiding complications is key. The other thing I would say, that's really important is irrigate frequently, keep the blood out of the field as much as you can because the more blood you have in the field, the less you can see, in particular, if you're using the endoscope, it absorbs a lot of light and it really degrades your image. And so, those are all things that I think are really important. You know, knowing the anatomy, I was just watching a talk by Juan Fernandez Miranda, you know, the anatomical knowledge that's out there now, in the skull-based community is pretty amazing. And I think that also is such a foundational key to success, but all these other things are in judgment and just not going, not trying to go for a great looking scan, go for, you know, a happy, great looking patient, I think is really the key. So.

- Thank you. Those are great pearls. We have sincerely appreciate your time today, and hopefully we can have you with us again, as a guest in the near future. Dan, thanks again.

- Thanks, Aaron. It's been a pleasure. Stay safe, bye bye.

- Thank you. Same to you.

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