Transcript

- Hello, ladies and gentlemen. Thank you for joining us again. Today we're privileged to have with us, Dr. Theodore Schwartz from Cornell University. Theodore we'll be talking to us about endoscopic transnasal resection of pituitary tumors. Theodore thanks again.

- Aaron thank you so much for having me today. I'm a professor of neurosurgery at Weill Cornell Medical College, New York-Presbyterian Hospital. Also have appointments in neurology and neuroscience and otolaryngology. Today I'm gonna talk to you all about endoscopic pituitary surgery. Try to cover what some of the advantages may be of using an endoscope to remove pituitary tumors, and also talk to you about some of the limitations and try to give an honest appraisal of this topic. I work at Cornell. We have an Institute of minimally invasive skull base and pituitary surgery. I worked very closely with an otolaryngologist named Dr. Vijay Varun, and in my opinion is very important for a successful endoscopic pituitary program particularly if one's gonna do extended approaches to have a collaboration between neurology, neurosurgery and otolaryngology. The rhinologist or the otolaryngologists really have a very strong working knowledge of endoscopy and nasal anatomy and nasal sinus anatomy. That can be extremely important in trying to approach the pituitary area as well as the parasellar area. So we're gonna go over a few topics in which the endoscope is helpful. I'm gonna divide it up into the approach then the resection. And I'll talk a bit about microadenomas versus macroadenomas. We'll talk about the closure and we'll also talk about complications. So why do we use an endoscope for pituitary surgery? What's the main advantage? Well, in my opinion, one of the limitations of the microscope is that when you use a microscope and you do a standard subclavia or even a trans nasal approach, you have your lens and your light source outside of a narrow tube. And that narrow tube is formed by the Hardy retractor. So the light can only pass parallel to the walls of the tube, and you have limited lateral exposure to the tumor. When you use endoscopy, you can actually pass the endoscope, which means the lens and the light source down to the end of the narrow tube, which is really the nasal corridor and your lens and your light source are at the bottom. So you can look all around and you can see the extent of the tumors, and you can look around corners. We use a lot of intrathecal fluorescein in our surgeries. And I say that because when I show you some of the movies, you're gonna see that the cerebral spinal fluid is dyed green. We pretreat these patients with Benadryl and decadron, and we haven't had any adverse effects with using low dose fluorescein. We find it very helpful, not only in small microadenomas, at the end of the surgery to make sure there's no leak, but also in macroadenomas at the end of our closure, if there is a big tumor and a big CSF leak, we wanna make sure that there's no CSF leak at the end of the closure. So let's talk about the approach. In endoscopy, there is less disruption of the nasal mucosal, sort of at the forefront of the nose, but when you go deeper in the nose, when you do nasal endoscopy, there's actually quite a large opening in the anterior sphenoidal sinus. Some people will resect the middle turbinate, for example, to make room because you do need room for your endoscope, as well as your instrument. So although it's considered a minimally invasive approach, it's really pretty invasive once you get past about two thirds of the septum. So the opening that you need in the sphenoidal sinus is actually larger than you might need with a microscope, because the advantage of the endoscope is that you need to look around. And the only way to see around is to create a space to see through. Another advantage of the endoscope is that you're less likely to get lost because when you go up through the nose, there are a lot of anatomical landmarks. You have inferior turbinate, middle turbinate, superior turbinate, the ostium, the septum, all of those landmarks will be visible to you and I'll show them to you in a movie. And so the approach becomes much more straightforward. We do our surgeries, mostly with the endoscope on a scope holder for a lot of the surgery, although not all of the surgery, when we need to look around corners, we then take a 45 degree or a 30 degree scope and have my assistant navigate that scope and manipulate it so I can see while I'm operating around corners. But when I'm working straight ahead in the I'd rather have that scope held steady. I like my eyes not to jiggle around. And I find that an advantage. We do a lot of the surgeries through one nostril, and then sometimes we'll elevate the endoscope and work with one hand in each nostril, particularly if we wanna work towards the patient's right, we need to triangulate down. So it's useful to have a hand going in the other nostril. So with the transsellar approach, again, here's the anatomy that we see endo nasally, the corona you see straight in front of you, the middle turbinate is up to the left. We're on the left side of the septum. And the septum is in the midline. When we go past the middle turbinate, we see the superior turbinate and just medial to that superior turbinate, you can see the ostium of the sphenoid sinus. Now the ostium of the sphenoid sinus sits about a third of the way down from the skull base, two-thirds of the way up from the floor of sphenoid sinus. So when you open your ostium, you wanna open inferiorly. In this picture, you can see that we've taken the posterior septum down. We're looking at both ostia of the sphenoid sinus now bilaterally. And once we remove the remainder of the septum and the rostrum will have a great view into the cell at the back of this anti wall the cell or the backlog of the sphenoid. This view shows you this panoramic view where you can actually see the carotid arteries and the carotid prominences, you can see the clivus, the sellar floor, the clivus the other side, sorry, the carotid on the other side. When you look up and laterally, you get a good view of the optical carotid recess, which is between the optic prominence and the carotid prominence. You have a very good idea of where the optic nerve is and where the carotid is based on the bony anatomy of before you even drill the floor of the sellar. When you look upwards above the sellar, you can see the tuberculum sellar, and we drill this off and we're doing large macroadenomas, and I want to get an extra capsular dissection. I'll show you an example of that. And we can also remove the planum sphenoidale, which sits a yet above the tuberculum sellar for even larger tumors. This would be a standard opening we would use to take out a pituitary tumor, we'd like to open from cavernous sinus to cavernous sinus, get a really big opening all the way down to the floor and up to the tuberculum and make sure we have great exposure. And then we would generally take a doppler at this point, make sure the carotid artery was not in our field before we began to open the dura. So I'm gonna show you a movie of the approach and Aaron, if you could load that movie up, please. So in this example, we are moving through the nose. You can see the middle turbinate and you can see the septum on the side. We're coming up to the ostium on the left side, we're gonna open the ostium with a mushroom punch and that'll take us right into the sphenoid sinus. So it's really can be that simple. We're gonna... here you can see the ostium opened up. Now we're taking a tissue shaver and taking down the septum, cauterizing and cutting the septum to create a large cavity in the back of the nose, here you can see from ostium to ostium a large cavity that will fit the instruments as well as the endoscope so that we can work and see in this cavity. At the end of this opening, you can see the sellar, you can see the septations within the sphenoid sinus. And then we'll remove a bit more of the post-arrest modes here to see above and enlarge this opening to do our surgery. We move back to the slideshow. Actually, I can click on it.

- I haven't had you very well mentioned the fact that in endoscopic approaches, maybe upfront before you get to the sphenoid, there is less invasion, but when you get into sphenoid, actually there's potentially more invasion than using the typical Hardy retractor. Do you think if you compare them combined, which instrument causes more I would say soft tissue and bony, I guess, invasion, the hardy retractor or the endoscope?

- So the endoscope in and of itself doesn't cause any damage whatsoever. So the opening that you make is made by a Kerrison drill, or it's made by a drill or a tissue shaver. So as opposed to a Hardy retractor, which, you know, when you turn that Hardy retractor to get more and more opening, it's sort of a uncontrolled opening. And if you turn it too far, you can get a fracture. You know, either of the steroids or other structures, that could be very dangerous. So the endoscopic approach at least is very controlled. And although the opening you make deep is larger and potentially there's more risk of getting bleeding from the sphenopalatine artery. You can see everything. So everything's done in a very controlled manner. And if there is bleeding from an artery, you can cauterize it and cut it. And so if you look at nasal outcome after these surgeries and people are comparing this, I think that in the short run, the nasal outcome may be a little bit worse, but in the long run, I think the nasal outcome is probably better with nasal endoscopy. So moving on, I'm gonna talk a little bit and show an example of a small microadenomas. What do we do with the sphenoid mucosa? Well, in small tumors, we try to preserve the sphenoid mucosa. And if we can keep the mucosa intact, you can actually close the mucosa at the end. If we're doing a large tumor and we're harvesting in nasal septal flap, then you'd wanna remove all of the mucosa. Because if you lay your flap down, you can get a mucocele behind the flap. If you don't remove all of the mucosa. Can we show the next movie, please?

- Thank you.

- So in this movie, we begin by opening up the mucosa over the sellar. We've done the approach and we gently flap back the mucosa and try to preserve it. We will, you know, put pieces of gel foam in there and patties to stop the bleeding and keep them mucosa back. And then we can create this mucosal window and drill the floor of the sellar with a diamond drill until we get to the dura and click off some of the bone. It's very thin, but then try to use a Kerrison to make a controlled opening of the bone. Cavernous sinus to cavernous sinus. Here we are using a sickle knife to open up the dura, and then we will try to remove the tumor. In this particular case, the tumor was large enough. It was hard to do an initial, extra capsular dissection so we chose to do an internal decompression first. We send off our specimens to pathology. The first move is usually to remove a tumor from the inferior portion of tumor all the way back to the back of the sellar, and then start to work your way laterally along the medial wall of the cavernous sinus. You can see with the endoscope here, we have an angled endoscope looking around. You can see around the corners, you can see the walls of the cavernous sinus. You can see little bits of residual tumor that may be hanging down from above attached to the pituitary and diaphragma. And all of these can be removed under direct observation. There is a little CSF leak in this case, you can see some green fluorescein. So we fill the sellar with fat. We like to buttress it with a small piece of Medipore reconstruct the floor the sellar, so that fat doesn't fall out. And then we will try to close the mucosa and you can see that the mucosa will kind of stick to itself and you can reconstruct the mucosal closure and then put dura seal. We'd like to use dura seal over that, just to make sure there's no CSF leak. After about a week or two, that dura seal will be absorbed. And we wouldn't do any further closure in this situation. No nasal simple flap would be indicated because it's a fairly small tumor. Next slide. I'll go back to this.

- Theodore I have a question. How do you close the mucosa together? You use sutures, I assume it will be difficult to suture them at that level.

- No, we just approximate the mucosa and by approximating it, it tends to stick together. And if it didn't stick together, we wouldn't suture it close. We just leave it where it is. But if you have enough of the mucosa freed up, there's enough slack on it, that you can actually bring it together and get it to stick together as we did in that case that I showed you. So in terms of now resecting tumors, I have to say that for microadenomas, the endoscope probably is not such a huge advantage over the microscope. We have been removing microadenomas with a microscope for many years. Surgeons were very good at it. And if the pathology is straight in front of you, I think that a microscope is a great way to remove these tumors and an endoscope is not necessarily a huge advantage. There may be an advantage. There may not be an advantage, but it's gonna take a huge number of patients first to answer that question, 'cause I think both surgeries are probably equally safe and effective. Here's a video now of a resection of a microadenoma. We could go to the video and what this is gonna show is an attempt at an extra capsular dissection. This was a non hormone producing tumor. It was a little bit on the large side to get a complete extra capsular dissection, but we always try to preserve the capsule in the plane between the pituitary tumor and the normal pituitary gland. So what you see here is we're flapping back the leaves of the dura, covering the normal pituitary gland. And then we find a plane of dissection between the tumor and the normal pituitary gland. And this is really helpful, not only to preserve the normal pituitary gland, but to try to make sure we get out the whole tumor. Now it is not always possible to get a on block resection of pituitary tumors 'cause they're very soft and the capsules are very small. Although we always try to do that particularly with tumors that are less than one or two centimeters. In this situation, what you'll see is that we began that effort. And then unfortunately we got into the tumor a little bit and had to internally decompress it, but we were able to get most of the tumor out in an unblocked fashion to the point where we were very comfortable seeing what the plane of dissection was between the tumor and the normal pituitary gland. And we could preserve the gland and take out most of the tumor. In a minute, you'll soon see that the tumor is out except there's clearly some residual tumor left behind, there's some CSF leak above the normal pituitary gland. So we take our instruments and try to get out the residual tumor. In order to do this more successfully, we'll take an angled endoscope and angled instruments and try to dissect off the last bits of residual tumor from the interior portion of the normal pituitary gland. And here I think is one of the advantages of endoscopy for small tumors. It's very get hard to get this kind of a view around the corner as the pituitary starts to descend into your cavity without having angled view with a 45 degree scope. The closure again, because there's a CSF leak, involves a fat graft, a little piece of Medipore, and then we'll cover it with dura seal to make sure there's no postoperative CSF. Here's just a post-op scan showing a nice image of a fat graft within the sellar. You can see the normal pituitary gland above. You can see the size of the opening, which really extended from the tuberculum down to the floor of the sellar. And on this view, you can see the stock. And then of course the normal pituitary gland off to the right side, as well as above and the fat graft in the area of the tumor. And you can see how the resection went all the way to the medial wall of the cavernous sinus. Here's the carotid and near the cavernous sinus.

- You know Theodore, I really like what you mentioned that I agree that endoscope may not be a significant advantage in section of microadenomas, but it may be an endoscopic assisted micro surgical removal of the adenomas is different, would be something very desirable that I personally use. In other words, use the microscope to clean it out real well, but at the last, for the small pieces at the end, because really resection of the functioning tumors is so important as much as you can that using endoscopes to make sure all the last pieces are out is really a significant help. Thank you.

- Yeah I think that if you're transitioning to endoscopy and you wanna start with a microscope and then put the endoscope in the end to look around, I think that's absolutely reasonable for microadenomas. For macroadenomas, I think it's a slightly different story, particularly bigger ones, because I think with the development of endoscopic skull-based surgery approaches, we've now started to do much bigger exposures, the super sellar area and of the cavernous sinus, that many surgeons are not comfortable doing with a microscope, although some are of course, and I'll show you some examples of that. So it's really in the macroadenomas that I think the endoscope makes a bigger difference with improved visualization. We can look around corners to the lateral of sellar. We can look into the cavernous sinus, we can open up the cavernous sinus. We can go through the planum and to break the lump to the suprasellar cistern. And of course, down into the clivus as well. An example of lateral visualization will be given here in the next video. If we could start that one, this is an example of a macroadenoma that we took out mostly with a zero degree scope. And then what happens is the arachnoid and the diaphragma start to herniate down into your operative field. So we go in with an angled scope and we felt we took out all the tumor, but the... and the diaphragma herniated down, but perhaps not as far down as it should have. And then with an angle endoscope, we were able to look up into a corner and see a significant amount of residual tumor in the lateral gutter that we couldn't see with the zero degree scope. And you might not have seen it with a microscope either, but with an angled endoscope, you could really see up into that corner and take out the residual tumor and get a more complete resection. So one of the advantages of the endonasal approach is that it is in my opinion, easier to get into the cavernous sinus, at least the medial cavernous sinus through an endonasal endoscopic approach. We as we all know, the anatomy of the cavernous sinus is such that cranial nerves three, four, the first and second divisions of the fifth cranial nerve or in the lateral wall. And when tumors arise medially, they push these contents further laterally. The sixth cranial nerve can sometimes be within the cavernous sinus, but it is also lateral to the carotid artery. So there's a corridor through breaks in the medial wall of the cavernous sinus. So we can follow and take advantage of the trajectory of the tumor to get tumor out of the cavernous sinus. Here's an example of a tumor that invades into the posterior cavernous sinus from medial to lateral, that we removed through an endonasal endoscopic approach. The way we do this, is you remove the bone over the cavernous sinus, and you can do that because the cavernous sinus contents are intradural. If you take your doppler and doppler out the location of the carotid and you open up the sellar all the way to the carotid, and then you can work with angled endoscopes and angled instruments around behind the carotid as you see in this example. Here let me just get my pointer activated. As you can see here, we're working behind the carotid with an angled suction and angled scopes. And the key is that we're doing this under direct division. It's not blind scraping of the cavernous sinus. So here's an example of a tumor invading into the cavernous sinus that we resected. And there's a movie where I can show you an example of a direct visualization of cranial nerve six, and you can see that we're able to see the nerve, see where it is and remove tumor adjacent to the nerve without damaging the nerve itself. Here's an example of the carotid artery, the nerve, and the tumor adjacent to the nerve that we're resecting with a suction as a soft suckable tumor without overly transplanum. But I think it's the greatest approach really for the extended transsphenoidal approaches and the greatest advantage of endoscopy is in these extended approaches for giant tumors that go up into the suprasellar cistern. These are for three centimeter, four centimeter, five centimeter tumors that are extending into the suprasellar cistern, compressing the optic chiasm. And in these situations, we can do extended approaches and drill out the plane and then tuberculum in order to perform an extra capsular dissection. This is just an example of the bony anatomy that you'd see coming in from below. In addition to opening up the sellar, we will drill out some of the tuberculum and in some circumstances, even some of the planum, depending on the size of the tumor and what's needed. Here's an example of a pituitary tumor that extends anteriorly over the planum. It should be essentially impossible to take out through a standard transsphenoidal approach of if you already just open the sellar. But if one takes a drill and drills off the planum and uses an angle, 30 degree endoscope to look upwards, you can remove the entirety of this tumor through a purely endonasal approach and avoid a craniotomy and avoid any brain retraction. This is just a post-op scan with some fat graft in there that is taking the place of the tumor that we resected. The fat of course will go away over time. Here's another example of a tumor that extended over the planum. You can see very clearly here, the bone of the tuberculum and the bone of the planum that needs to be removed. And we use our navigation to determine this in order to get out the suprasellar tumor, and sometimes tumor that's even invading into the frontal lobe. There's an example of that on a coronal slice. Here then is a post-operative scan. And this situation we've harvested a nasal separate flap. So when we did our closure, we placed a flap over this 'cause obviously there was quite a large CSF leak at the end of the surgery. And you can see we remove the tumor up into the frontal lobe and left a back, perhaps a piece of Medipore, and then a nasal separate flap below. And I'll show you examples of that closure, even giant tumors that extend through the frame of the medial wall into the lateral ventricles can be removed through a purely endonasal approach. And we can avoid a craniotomy that shows you the post-op scan. You can actually see the piece of Medipore here and then fat graft holding Medipore host fat graft place. Here's an example of another macroadenoma. I'll show you a video of this one. You can see that this large suprasellar part of the tumor from action below may be difficult to remove, but if we remove this part of the tuberculum, we then can go extracapsular and have a direct view above the tumor in order to get out it's residual contracts. We use our navigation again to show us how much of the tuberculin planum needs to remove. We don't wanna remove too much more than we need. We wanna remove just the right amount. Can you play this video, please. So in this video, we're doing a removal of the floor of the sellar, and we wanna go all the way lateral, just to the cavernous sinus. And in this situation, we removed all the bone that we would need to remove for a standard transsphenoidal procedure. Here we are taking the floor of the sellar. We wanna get all the way down to the floor, but then in order to do this extended approach, we have to take a drill and drill out the tuberculum. And then you can see how the dura changes its consistency when you get to the tuberculin and the planum above the in dag dura within the sellar becomes a much wider and much thicker. That's when you know that you're starting to go into the suprasellar area, we take a Kerrison and keep removing the planum until we have an adequate exposure that mimics our exposure laterally, where we know the cavernous sinus is. Here we're going back to a diamond drill to further remove more of the tuberculum and now starting to remove some of the planum sphenoidale in order to work above just the standard approach that we would get by removing the sellar floor, or the doppler is very important here to make sure that when we open up the dirt, we don't open into the carotid artery or even the coronia artery. And then we'd like to make our incision, of course, in the midline where we know it's safest, start in the midline where you know there's tumor and then tank angled scissors and extend our incision in each of the four quadrants. You can actually see the nasal septal flap, where we store it up for the end of the operation, waiting through the end of the operation. Once we've completely opened the dura, you can see there's a very large tumor that can't wait to get out. And we dissect the dura away from the tumor in all directions. And then we'll start to internally decompress this tumor. This is not a tumor we can take out on block. It's a very large tumor. So we first do an internal decompression and then we try to work the capsule. Of course, it's nice to get a frozen section at the beginning of the operation. And then we do our resection of the inferior part of the tumor. We work in all four quadrants. We start in purely sucking out the tumor and go all the way back. We wanna get back to the back of the sellar. So we know the posterior margin, and then we'll start to work our way laterally under direct vision, taking tumor out along the medial wall of the cavernous sinus on either side, starting on one side and then working on inside. We don't want those superiorly too quickly because then the diaphragma will descend into our field and won't be able to see. Now you can see the diaphragma actually beginning to descend here. We still have some more tumor. And now we start to work suprasellar. So this is the capsule of the suprasellar tumor that we're taking out in an extra capsular fashion. You can see how the ability to retract the dura and the normal pituitary gland superiorly is very helpful. You can see the fluorescein on the other side of the arachnoid, and we try to preserve that as best we can and as carefully as we can, although we often have retinol in the arachnoid that cause CSF leaks, we try to make those as small as possible, but often they are quite large. We try to preserve that plane and continue to dissect the tumor out as much as we can on block, because if we have the tumor breaks up, it's fairly easy to leave a large chunk of tumor behind, and we don't want that to happen. So we try to preserve the tumor in one piece. Here we are working laterally as well as superiorly and continuing to try to work the plane between the tumor and the normal pituitary gland. Here's you can see a fairly large retinol in the arachnoid above, but we're very comfortable closing weeks like this. And I'll show you how we do that. We continue to work the tumor until we can get it all out. A small bit of residual tumor left laterally. There's bleeding in the medial wall of the cavernous sinus. Now we work laterally to the other side, you get a small amount of tumor off the medial wall, the cavernous sinus on the other side. At the end of the operation, we irrigated out, put some patties in there, try to get good hemostasis. These giant macroadenomas do you have a tendency to bleed afterwards. I will often fill the cavity with flow seal and then irrigate out the flow seal. And then when we have good hemostasis, we fill it with that. We buttress it either with Medipore or a piece of bomber. This is a piece of bomber that we harvested to keep the fat in place. And then we'll cover this with a nasal septal flap that the ENT colleagues can harvest at the beginning of the operation. Here we are bringing the flap up from the nasal cavity nasal pharynx. We wanna make sure that the nasal septal flap covers the entire defect and lies flat. Make sure that it's the mucosa is facing in the correct direction. So it's producing mucus outwards and not inwards, but we have to make sure that everything is covered. And then we keep it in place by using dura seal. Although other sealants can be used, we like to use dura seal and we'll take a 14 gauge Angie cap and put it through a rain curate in order to direct the flow of the dura seal exactly where we want it. So that's how we take out giant macroadenomas, and here's a post-op scan. So it shows you we remove this big tumor. Often the cavity expands. This is post-op day one or two. You'll see an enlarged cavity with a fat graft in there, and this will all descend over the next month. It'll come down and you won't see anything. And then you can see the cavernous sinus on either side could be free of tumor. Here's just a lateral view of that with a fat graft covered by this nasal septal flap and a piece of bone, you can see it in black line here, which is the bone we use to buttress the fat graft so fat doesn't fall out in the nose. Often we will see patients who have had prior microscopic sub labial resections using a Hardy retractor of macroadenoma, and there will be residual tumor in the suprasellar cistern that they were not able to see. And this is just an example, the case that had a prior transsphenoidal surgery, there was some residual suprasellar tumor. We went back in and did an extended approach. Can we see the next movie please? And what we generally do in these situations when there's residual tumor is we'll go back and find that the prior surgeon may not have removed enough bone and that the opening may not have been adequate to see the suprasellar tumor. And so we'll drill out more of the planum and more of the tuberculum above the prior opening in order to get exposure into the suprasellar cistern. I like to use a diamond drill to avoid tearing the arachnoid. Here we are removing the prior bone graft that was placed by the previous surgeon, and then take a Kerrison to enlarge that opening and open up the dura. And you can see the optic nerves above and often we're working in direct view of the optic chiasm, and the optic nerves in order to do suprasellar tumors, particularly those that extend into the third ventricle. Here we're using sharp dissection. As I dissect a tumor, that's very stuck to the floor and the inferior aspect of the optic chiasm and dissecting it free from the normal pituitary stock and the superior axial arteries, which can often be seen laterally. Here we're beginning to see a view into the third ventricle. You can see the apendima of the third ventricle posteriorly, below the optic chiasm, and we'll carefully dissect residual tumor off the back and inferior aspect of the chiasm. We're looking up into the move for the third ventricle. You can see the framing of monro or indices or Lexus, the mass into radial and the telecoradial. They're all clear and free of tumor. That's how we know that we've accomplished what we wanna accomplish. I'm gonna move on to the next movie for the next case. So here's a post-op scan. Let me just go back. Here's the post-op scan, and you can see how we've gone up into the third ventricle to remove this residual tumor and get a complete resection. Here's just another example of a tumor that was left behind after a prior transsphenoidal surgery. And once you can see his residual suprasellar tumor and on the post-op scan, after an more extended approach, we were able to remove the rest of the tumor and go up into the third ventricle. This next case is particularly satisfying. This is a young girl who's given us permission to show her image who had a gigantism. This is her at age nine. This is her at age 11. She grew dramatically. She had a prior transsphenoidal surgery. And after that surgery, some residual tumor was left in the suprasellar cistern and she was told that this was a unresectable and she would have to be treated with medication, which wasn't working. As you can see the residual tumor is not difficult to approach with an extended approach, although it isn't a suprasellar cistern and I'll show an example of how we took that out. Can we go to the video please? So once again, we extended the bony opening from the standard transsellar approach and extended it to transspheniodal approach. Here we are going through the prior opening. You can see that there's been remiparcelization. Once we remove the mucosa, we're now extending the prior opening into an extended approach by removing some of the tuberculum. We'll then open up the dura. You can now see the optic chiasm optic nerve, the arachnoid reinforcing, and here's the residual tumor it's right in front of us. When you do an extended approach, we'll dissect the tumor free from the arachnoid and dissect it free from the bottom chiasm, doing careful extra capsular dissection, not trying to pull on anything, cauterizing and putting any attachments that may be found between the optic chiasm and the tumor itself. We use microdissection techniques, even endo nasally, and we now have instruments that we can use that are bay and edit. And here's the residual tumor that we're removing from the suprasellar cistern. There's now some more soft tumor attached to the back of the chiasm and the floor of the hypothalamus that we can gently dissect free and make sure we get a complete resection, 'cause of course, we're trying to cure this young girl of gigantism interact from haggling and we can only do that with a gross total resection. Finally, some tumor left along the diaphragma is removed sharply by first blindly, and then sharply by dissecting it off the residual floor of sellar. And after surgery, you can see, we can look up into the third ventricle and get an excellent view of the clean third ventricle. This is fascia lata that we use from time to time when we do extended approaches, this is our gasket seal closure. We take a piece of fascia lata that's larger than the opening. We buttress it with a piece of Medipore, to make sure that it doesn't move. This ensures a watertight fascia and that the fascia lata does not all out on the skull base. And then we can cover this with a nasal septal flap. And in this situation would probably use a lumbar drain as well, or they are too. As you can see in the post-operative MRI, the suprasellar tumor has been completely removed through an extended approach. You can see a small piece of Medipore that is holding the fascia lata in place, which is of course what the gasket seal tries to achieve. And she was cured of her acromegaly. So thank you very much. I hope this has been an illuminating discussion for all of you about some of the advantages of endonasal endoscopy, as well as extended skull-based approaches and the removal of the pituitary tumors. I like to think that endoscopy has added quite a bit to a removal of pituitary tumors, but there still is debate there and still are some outstanding surgeons who only use a microscope. So this is not to say that one must use an endoscope, but it's one perspective and one point of view that I think is of value. Thank you very much.

- Thank you, Theodore. And I wanna appreciate for a superb technical job in terms of showing the videos really being one of the leaders that you have been in endoscopic surgery, I think endoscope is definitely a big and important endometrium in the hands of skull-based surgeons. And I think its role would only expand with time as instrumentation and people like you would push the limits further and further again, thank you for your time.

- Thank very much I appreciate

- And we'll look forward to having you with us next time.

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