Grand Rounds-Technical Nuances for Resection of Craniopharyngiomas

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- Hello, ladies and gentlemen, and thank you for joining us. We have one of our special guests back, Dr. James Rutko from University of Toronto. He will be talking to us about nuances for resection of craniopharyngiomas. We have a set of very exciting videos and that are coming up shortly after his brief slides. And I would like to thank Jim again for being so gracious and we all enjoy his great expert comments. Go ahead please Jim.

- Thank you very much, Aaron. It's great to see you again, and I'm happy to do this one in particular because craniopharyngioma has a lot of mystique and intrigue around it, and I'll just go through a few of my introductory slides for you. But at first, I just want to say I have no disclosures, just so that's quite clear. At the outset, we do realize that this is a very rare tumor, but because of its challenges by virtue of its location, it causes a lot of as I say, intrigued in the neurosurgery community. These tumors can be cystic or solid. The whole key to craniopharyngioma is actually it's attachment to the hypothalamus and it can be found anywhere along the hypopituitary and hypothalamus stalk. So here's a case very interesting years ago, I followed this child who had this lesion here that you can see, and it grew as of January, 2000. You can see that the lesions a little bit bigger, the child had headaches. I wasn't sure that the headaches were being caused by this lesion. But over time, after waiting about six to nine months, you can see the lesions much larger, and we decided to do surgery at this time. So craniopharyngioma is clearly will grow over time. One useful classification of craniopharyngiomas is sellar, which usually causes endocrinopathy, prechiasmatic causing visual failure or retrochiasmatic causing endocrinopathy and raised intracranial pressure. If you're going to do surgery on craniopharyngioma, especially in a child, you need to know this relevant regional anatomy, including optic nerves and chiasm, pituitary gland stalk, hypothalamus, intercranial carotid artery, anterior circulation and cranial nerves one through three. Clinical investigation is very important. There is a formal neurological exam neural endocrinological exam, neural ophthalmological, neural radiological, and finally neuropsychological examination. All of these should be performed when time permits on the child with craniopharyngioma. Treatment options include conservative management, which usually isn't very wise over the long run surgery biopsy versus resection chemotherapy, predominantly inter cystic therapy, radiation therapy, hormonal therapy. That means the introduction of endocrine hormone replacement therapy. Some of the avenues that you can pursue to approach craniopharyngioma include transsphenoidal, subfrontal, pterional, subtemporal, anterior interhemispheric, transcallosal, endoscopic and combined approaches, especially for the large craniopharyngiomas. Here's a very good paper from a few years back in the journal of neurosurgery by Van Effenterre and colleagues. And basically I had written to show that we really don't know what the best strategy is for craniopharyngioma. And so as a result in the future without class one evidence, it's really important for us to keep asking what is the best treatment for craniopharyngioma. I'm just having a little trouble advancing my slides here, here they are. So here's an article two by Jeffrey Wisoff, and this is a more contemporary 2010 article showing that in his viewpoint, Jeffrey Wisoff has been an advocate of radical surgery, gross total resections easiest at first presentation. However, in his series, there were three perioperative deaths, but he showed that subtotal resection, tumor size, hydrocephalus, and VP Shunt, all predicted negatively for progression pre-survival and overall survival. And he did recommend that an experienced surgeon that'd be responsible for a surgery in these cases. I like to show a case of a 12 year old female in my own practice as child presented with right visual failure, you can see on the sagittal view, there's prechiasmatic craniopharyngioma. So here you can see on this particular CT scan, calcium that is around the cystic capsule of craniopharyngioma, and this is virtually pathic mnemonic for this particular tumor. Here on the sagittal image, you can see that it is in fact, a prechiasmatic craniopharyngioma. And here's the same case prechiasmatic. You can see left optic nerve plaintiff's Finley dally. Here, you can see the tumor, subfrontal approach was used in this case. And as we approached this tumor, you'll see that we get further exposure. And basically what we did was exaggerates here, the tumor from the prechiasmatic space. Here, you can see the primary processes, post your planning process of sellar here. Here's the plane on dally. And then finally this leads us to an excellent resection. We use mirrors typically, or now the endoscope to look to see if there's any fragments of calcium left behind after the tumor has been excised completely. Here's the immediate post-op in this case. And what you can see here is a complete resection. Now many years later, this is what you'd like to see is removal of craniopharyngioma and here's the chiasm from above here. This was a child who had an excellent post-op at the course and had no additional complications after surgery with the exception of endocrine hormone dysfunction, which was treated with endocrine hormone replacement therapy. Here's the same case. I'm going to show the child of age seven and before surgery, here's age 10 now, and then age 12. When surgery was performed, here you can see this child age 13, three years later. And now here you can see at graduation. This child did not develop any change in body habitus because this was prechiasmatic craniopharyngioma. Unlike those that are retrochiasmatic where you can see on morbid obesity that can result from some of these cases. Some of the nuances for craniopharyngioma surgery. What you can see here is that supine, bicoronal scalp incision, orbital osteotomy, orbital roof cut, and ligation at times of the superior sagittal sinus divisional fault, gentle frontal lobe retraction that's key. So using a skull-based approach like this, we open CSF cisterns, drain CSF, and on occasion, if there's quite considerable hydrocephalus, we can use a ventriculostomy. Here's an adjunct. So this is the orbitotomy or orbitozygomatic approach can be used with good results for craniopharyngioma. There's another case six year old female, progressive visual loss in the left eye, short stature, was otherwise well. We did a number of investigations, including neuro psych testing before surgery. Here's the MRI scan. What's interesting about this MRI is the rather by lobed nature of this cystic craniopharyngioma. You can see one going up towards the base of ganglia here, another one in the temporal lobe in the next slide should be the video. So just keep in mind here, this basal ganglia component in this cystic component here. So the video I think is going to be brought up shortly. Here it comes, and you'll be able to see the operative approach. Now you can see my pointer showing these large cystic structure, and here we are operating manipulating here the carotid artery. Here's the systemic craniopharyngioma here that you're seeing as we're separating the carotid, basically from the optic nerve. Here you can see the separation further.

- And Jim, which sided approach is this? Would you please let me know.

- Yeah, we did it this in essence, through our favored to self frontal approach. And what you're looking at here is the right optic nerve. We would have done a unilateral sub frontal approach. So here as you can see now the middle cerebral artery going off to the side. This is the temporal component of the cyst that we're now dissecting carefully off of the middle cerebral artery. Here's the A2 segment. Here's the temporal lobe cyst that's coming away here. You can see the nice plaintiffs developers were removing this lateral cyst. Here's the right optimum. Now here's the large central prechiasmatic cysts that's being mobilized and taken away. And we're decompressing the cyst all the while, but it's coming away quite nicely you can see. It has rather large mass to it where we're able to remove it completely in this fashion. And here we are taking away the cyst from the chiasmatic space, and this is a cyst make inter operatively, but there's pituitary stalk coming down. It was infiltrated by the tumor. There was no way to separate this tumor from the stalk. And so we made that inter-operative decision to sacrifice pituitary stalk. Now using mirrors as shown basically to complete the resection. Here's a nice view showing the hypothetical.

- Always do an orbital psychosomatic for a standard craniopharyngioma. Do you do only if it's sort of high writing. So your bread and butter approach for craniopharyngioma. Could you please take us through that.

- Sure, so basically subfrontal approach with head slightly tilted back, a unilateral craniotomy frontal with orbital bar removal, then the dura is open and very gently as mentioned, elevating the frontal lobe until you get to the cisterns around the optic nerve and chiasm. And you're able then to drain a lot of CSF and you know, the whole worry here is not to do from retraction of the frontal lobe for fear of the frontal lobe injury. So that's been our standard approach. There are many others orbitozygomatic. I think later we'll see one of your cases that we'll show this, but basically this is a very decent approach for prechiasmatic craniopharyngioma. So here's the next next slide, I guess. And this was very interesting case. This is a child who had loss of vision, but look at this. So 1.5 years, so very young at the time of presentation. So because of this large, as you can see here, cystic craniopharyngioma, we wanted basically at first to put in Ommaya reservoir. There's the Ommaya that had been put in place, as you can see. And we'll show the video in this case. What we had in this case was a series of treatments with intercystic therapy with bleomycin after the child reached a certain age of maturity, which was about three or four years of age and the bleomycin wasn't working any further, we elected to do this surgery and you'll see the video coming to view now. So I won't show the whole video Aaron, because it takes time, but I'll show you some segments of it. So here we are opening it to the cystic now. You can actually see the Ommaya reservoir catheter in the depths of the cyst here which you can see. Now we're mobilizing the capsule and basically taking away more of the cysts that you can see. This has a very thick walled capsule, as you can see by virtue of having treated the craniopharyngioma with bleomycin. We are the second now off of the right optic nerve, which is located here that you can see. Here's the cyst wall, and you can see how thick this cyst wall is. And it'll be very careful as mobilizing the right optic nerve. Here we are mobilizing the left optic nerve, which you can see here. I need to advanced the video a little bit here because I think we need to see all of this. Here we are. A very thick calcified fragment that you can now see that's coming away. This calcium obviously shows up on the CT scan as we discussed at the very beginning. I wanted to show this aspect of mobilizing the fragment from the sellar, because as you're doing this, you're coming up against the cavernous sinus and what can happen sometimes is you can end up with some bleeding in the cavernous sinus, which may show up later. Here's M2 branches and they're stuck to the cyst wall capsule, which you can see. And it's very critical that these be removed with microdissection so as not to either cause them to go into spasm or to injure them, because you can end up with any pairs or stroke on that basis. Again, dissecting it off the right optic nerve. You can see here and we're taking care to be very credent about not injuring any of the micro vessels going to the optic nerve or the optic nerve itself is very, very key. So now I'm just going to advance the video a little bit more and see where this takes us here. Yeah, we're getting to a point now, we're in the right lateral sellar. This is the point I was trying to mention to you previously, what you'll see shortly is some bleeding coming from the seller and how you control. That's very important here. You can see some brisk bleeding coming from the cavernous sinus. Hope you can see that that's going to need to be stopped with some gel foam that's coming into view there and packing off. We'll be able to continue with the dissection and carry on, but it's very important that you know how to deal with bleeding like this, as it might arise, especially if the cyst wall is extremely rigid as it was in this case, it can be stuck to all sorts of important to neurovascular structures, including the cavernous sinus. So that stopped it up and we were able to continue the operation, just going to advance a little bit further here. Now we're moving to the superior pole of the cavernous or sorry of the cystic craniopharyngioma that you'll see, it's coming away quite nicely here and moving other pieces of the craniopharyngioma. This is a piecemeal resection could not be delivered all in one fragment because we had prior craniopharyngioma cystic scleral therapy treatment, which causes this not to be removed in one piece. Now here, you can see actually cutting the catheter, which is then removed at the end of the procedure. And again, dissecting more microvascular removal. Here, we are using a technique to mobilize the capsule further, take it away further. Now the left carotid artery is being dissented away from the tumor which you can see here. And I'll advance just a little bit further here towards the end so we can get to see the anatomy, what it looks like as we get towards the end of the procedure. Here, you can see the catheter has been mobilized underneath this patty. You'll see beautiful demonstration of the basilar artery and the brainstem as we're dissecting. Making sure that we don't leave any of the pieces behind. Now, we're basically taking this all the way from the sellar, which you can see here. And then finally, the view as mentioned of the brainstem in many cases, once you've removed the entire portion of the craniopharyngioma, what you'll see is the brain. There's the basilar artery, posterior cerebral arteries, superior cerebellar arteries, and the brainstem being seen behind all of this beautiful anatomy that you can see having a carefully stepwise and in a piecemeal fashion in this case because of the prior stereo therapy, having remove the craniopharyngioma completely. And I think at the end of this video, you'll see basically the approach that was utilized. Calcium's all been removed and this child is going extremely well. So those are some of the steps, Aaron, to remove a of craniopharyngioma using this video sequence.

- That's great nuances. Before we go to my taste is I would like to ask from your, obviously your pediatric practice, how many percent of your craniopharyngiomas are approached through an endoscopic way around?

- Well, I think now you'll see more and more cases in the literature and we're certainly using it when the primary focus or location of the craniopharyngiomas in the sellar itself. So I have some other cases that if there's time, we can talk about later in show but basically we have endoscopic approaches that are being utilized now on a more frequent basis. The problem in children is that the corridor of entry to the endoscopic endonasal approach is smaller. And at times not permissible in terms of using the endoscope. For example, on that 1.5 year old that I mentioned in showed the case of, I don't think that would be suitable because the sellar is way too small. And so you must gauge their experience with endoscopy with actual lateral corridors that are committed.

- Sure, I'm gonna also try to show some of the nuances we have used and get your opinion, Jim, I think this is the head position we all agree. This is a lesion along the anterior cranial fossa. So you don't want to extend the head too much. And also you don't want to sort of turn it contralaterally too much because of the tempo load will be on your way. So I think a little bit of extension to make the male eminence to highest point and turning it maybe 20 to 30 degrees away from you would be helpful in terms of approaching the base of the fore lobe. These are very basic, pterional opening approaches. We put a variable here to minimize bone loss along the keyhole and sort of go with a drill. And what what's most important for us is really drilling the pterional really well, especially in adults and secondarily drilling the roof of the orbits. We have been able to by drilling the roof a little bit, just to the level of a thin bone over the par orbiter, avoid doing the floor orbital zygomatic or a modified super orbital zygomatic osteotomy. And at the same time minimize the use of fixed retractors and be able to access the lesion. Obviously opening the anterior limb of the Sylvian fissure is important. This is challenging case of mine. I would like to get your opinion on how you would have done it. Again, your cases are pediatrics, mine are adults. And so I think this way we can hopefully cover both basis. 47 year old male with bilateral visual dysfunction and a very long standing history of personality change. And as you can see, Jim, it's a very sort of multicystic mass in the suprasellar space. Most likely a retrochiasmatic craniopharyngioma, very attached, obviously to the pituitary stalk. When you look at a case, what are you thinking in terms of planning your operation?

- Yeah, thanks Aaron. So on occasion on the sagittal MRI, you can actually take a good look to see where the optic chiasm is, and it looks like this might be adhere for example. So as you said, this likely situated, this lesion is behind the chiasm. So I spent some time definitely looking at the sagittal to try to get the location of where the chiasm is as is shown here. But I also look at the coronal because I want to know what the relative attachment could be to the hypothalamus. So we're a little bit in front of the hypothalamus sphere, but certainly if you were to make cuts going posterior to this lesion here in this particular section, if you went further posterior, you could sort of see where the potential attachment is to the hypothalamus. In my experience, the craniopharyngioma is typically attached in the unilaterally, as opposed to bilaterally in a flare sequence on a coronal will really help determine where do you have to be most careful in your dissection and removal. So try to minimize where possible the involvement of the hypothalamus vis-a-vis the lesion itself. So those are all some teaching points for craniopharyngioma Sylvian.

- Thank you, that was very helpful. So let's go ahead to the surgical video on this person. We did a left frontotemporal craniotomy because we felt that the lesion is mostly to the right side. So we get a sort of cross courts. In other words, if they most of the bulk is on the right we approach from left. So you get a more view on the right side. This is orbital zygomatic approach as you very well mentioned to start because this lesion really goes high. So if you remove the supraorbital bar and really expose the bone over the eye, you can eye socket, you can really get it hopefully in fair to superior trajectory. We don't usually use a pterional approach, but in this case we felt it would be important . This is MCA as the Sylvian fissure is being generously open. And again, that's because we want to create as much of minimal retraction. we have gotten away from using fixed retractors for two reasons. Number one, decreasing retraction fore lobe. And number two, because I think it gets on your way. Here is opening retinoid over the optic nerve and carotid artery and we wanted to approach this through laminar terminalis. So I'll hand it to you if you want to comment here, Jim, please.

- Yeah, so I really like your comments, Aaron, about a retractor surgery and that's becoming more and more important, I think, and more and more papers are being written on that topic. And just as you say, it provides more room and it probably does less harm in terms of the traction injury to the brain. So that's critical. So you've got a really nice exposure that's coming here. As you say, this is left sided, this is your obviously optic nerve. You've got your carotid artery here and you're now dissecting very nicely the plane. In my experience is really important to release all of the arachnoid as you're showing here. And I like releasing the arachnoid, going laterally out this direction. And then coming middle. Just like you're showing here is beautiful dissection. Very important that to get all these arachnoid trans removed, because that will minimize once again the retraction, but also maximize the exposure that you're going to see. So you actually can't do enough of this. So you really have to spend time. This also allows you to aspirate the CSF that's required to get the brain retraction so desirable, and then to help you find him to concentrate on the lesion itself as you're doing the dissection. So I see you're doing exactly what I would choose to do, which is open widely all the CSF spaces and take care of the arachnoid, all these adhesion which you're doing the combination of sharp dissection, and in gently teasing the arachnoid apart. The very good technique that you're demonstrating there. Now you're going between the optic nerve and the carotid artery. And you're basically demonstrating structures beneath and starting to see a lesion looks like coming into view or there again some arachnoid that needs to be carefully dissected way.

- I think that's the third nerve Jim right there. Third nerve on the left side. That's a posterior communicating artery. And again, a posterior crinoid right there opening everywhere just to get a good view of the extent of the lesion, where you are. I think it really helps to minimize them on a retraction on a fore lobe. And it gives you a better idea about the sort of the pathol anatomy of the lesion. And this is a really a laminar terminalis. And this is always makes you nervous. This is the P column, as you can see. I use the mouth piece a lot in order to minimize extra movements and it tremendously helps. This is contralateral A1 again, opening very widely following the ipsilateral A1 more posteriorly, and this is the ipsilateral optic radiation, as you can see right there, and here is again, contralateral A1, ipsilateral A1. And just about there, you see how far we have to go to see that there is a discoloration, because this is what tumor is giving you, rather than trying to make an incision more anteriorly and injure something. You should look for what it gives you rather than the surgeon making a decision to make the pathology and the structures will be the rule that the surgeon demands and here you can see opening the finished part of the chiasm and a laminar terminalis. Any thoughts there, Jim?

- Yeah, so it's amazing how far back you actually need to go to see the spectral chiasmatic craniopharyngiomas in their full extent. So again, the point about being very precise and also methodical with the opening of the arachnoid right across your entire visual field under the microscope will help you to see exactly where the best entry point is. If you choose to use an approach like the laminar terminalis approach. And that's always thinned out when lesion is stretched beneath and you're coming from above and you're trying to open up into it. So it helps you to identify the best entry zone if you will, in the laminar terminalis. So there, you're starting to develop this further, which is really nice and lesion should be coming into view soon. Here, there it is, I can see it coming to view.

- How would you have done this difference, Jim, as you can see, that really makes every surgeon very nervous, very nervous to make so much dissection within the chiasm and laminar terminalis, but I really don't think there is any other options to approach this lesion. And the window you work is so small. So you end up like, using these pituitaries and yanking on things, but as long as you're careful and then use sort of the number six dissect proton six dissector, and just delivering it in your field, being very careful, debulking it, and then mobilizing the capsule as you can see from the surrounding optic nerve and chiasm. And what's very important is that really the perforators at the bottom of this tumor that I end up leaving a little bit tumor at the bottom, not to injure the perforators. Do you have any thoughts there?

- Well, I like your emotion here, Aaron, where you're doing what's called centripetal movement or dissection. In other words, you're pulling the tumors centrally as opposed to reaching laterally or beyond the confines. That's where you get into trouble with craniopharyngioma. If you start reaching beyond what you can see. So all of these movements that you're demonstrating, which is sort of central forces delivering the tumor into the center of your field of view is critical to stay safe with craniopharyngioma resections. And I would do exactly what you've done here. The concern about going through the laminar terminalis. Yes, it is a little daunting at first when you're doing some of these cases for the first time, but in fact, you're not actually operating on or in the chiasm and obviously you're developing that plane that's given to you as you've demonstrated. And it's amazing how well this is all opened up beautifully just by taking advantage of the laminar terminalis and what it gives you and as a surgeon, that corridor of entry, which is so critical to remove retrochiasmatic craniopharyngiomas. But I see now you're getting your gentle traction. That's very, very important. This will help liberate the attachments to the surrounding structures. In your particular case, you need to be careful as you're going a little further posteriorly to determine what the attachment is like to the hypothalamus because that's largely what can determine the morbidity of these procedures is the attachment to the hypothalamus. But I can see that it's coming out piecemeal. You're delivering it centrally. It is a rather from a craniopharyngioma, but as you mentioned earlier, the corridor of entry is small, but you have all that you need here to remove this lesion. So everything you're doing is clearly an important aspect and part of the craniopharyngioma surgery, continuing to work with those centripetal forces, avoiding reaching beyond what you can see because especially posteriorly, that's what can get you into trouble in the hypothalamus.

- Thank you, Jim. I think two points I would like to share with you is using retractors in this area, fixed retractors would be really associated with significant morbidity. You can see how I use resection as a dynamic retraction on A1. You're so far back, and you can see A1 right here coming and going out of the view. If you put a fixed retractor here, you really are going to be asking for trouble and potential cerebral infarction in the A1 territory. So you have to use the dynamic motion, get all A1 as much as you can when possible, and then sort of move in and out to let the brain breathe with blood flow into it. So I wanted to emphasize that using link charrettes to reach a little bit farther has also been very helpful to me because you're right, it is a little bit blind, but it's much less risky in my opinion, rather than putting a pituitary round duro in there and just pulling on something very blindly. And the second point is when the surgeon exposes this, it can be daunting. It almost looks like this is not resectable, but do you have to persist and debulk in the middle because it's interesting just about halfway through the debulking and mobilizing, you find that the tumor is going to give up almost. It's going to tell you, well okay, fine, I'm going to start moving my capsule. So not to have the surgeon be disappointed too early and continue aggressive debulking and the central pedulum motion that you talked about and you will see things will start working out, especially halfway through.

- Yeah, so I agree completely with you, Aaron. And there's some nice traction that's a really important to gentle traction to bring down that superior labial of the tumor. And that's critically important. When I started doing craniopharyngioma surgery, I learned from Dr. Harold Thompson, who was arguably one of the masters in his day of craniopharyngioma surgery, but he had a slightly different technique. He would grasp the capsule after he had done a modicum of microdissection around and he would just, pull and he would pull higher until the craniopharyngioma came down and out. And in his hands, he had very good results. But I think most of us nowadays would do what you're showing us here, which is stepwise patient methodical dissection, let the tumor come to you and continue to develop those planes. Now I can more space that you're creating. Here, you're using a bit of traction I can see, and that's important. And something that's really hard to teach someone is how much can you pull? How much should you, along on cystic fragments of craniopharyngioma and it's something that you just have to learn through experience and feel, but there's no substitute for doing good micro neurosurgical dissection at first around the capsule itself so that centripetal force that you've demonstrated here time and again, will help you continue to take advantage of planes and to remove the lesion in its entirety.

- Thank you, Jim, as you can see at the end is really at the base of the third ventricle that demonstrate the end of our resection. You could see also live in a white matter on the edges, right before finishing that shoulder wall of the third ventricle. Wall of the third ventricles really are in my opinion, the seat of the soul. And it's really important not to mess with those. If the tumors are here into the role of the third ventricle, it is best to leave a piece of tumor behind. I can tell you that most difficult complications of at least my career have come about when I was overly aggressive with tumors in the third ventricle. And here's the post-op MRI. You can see, I intentionally left some tumor at the bottom of the cavity because there were a lot of perpetrators that I thought it's important to safe. And I guess somebody would have said, maybe I should have been more aggressive at the bottom. Would you have been aggressive here, Jim, in other words, remove the tumor attached to the P column and enter a corridor and taking more risk at a chance of a better resection?

- Well, I'm looking at the coronal here and I'm demonstrating and it looks like there's quite attachment to the sidewall. And this is exactly where the hypothalamus is going to be. So that's a judgment call. It's an inter-operative judgment call as to how stalk it appears to be what the lay of the landscape is with respect to the adhesion, and to the vascular structures which you've mentioned. But I think we always have to remember at first do no harm because the main morbidity here removing this last piece would be a morbid obesity and or a profound hypothalamic injury that may not be at all recoverable and could lead to a devastating result in consequences for the patients. So I have no worries or concerns about your having left this portion behind, because if you're taking this away and you had either a posterior circulation in part or hypothalamic injury, you will not have served your patient at all very well.

- And I really appreciate what you mentioned previously, which it requires obviously a lot of experience. That it was really attached to one of the hypothalamus. It wasn't attached to both and I could get it from here and it wasn't really easily coming off there. Would you have been aggressive at the bottom here where the P column and antique corridor ultra come off of the charrette Jim or you leave a sheet of the capsule along those important lesions come off of the internal quarter posterior wall?

- Yeah, so just as you did, I would have explored as best as possible the anterior circulation completely, you showed yourself walking along the carotid to the A1 segment, A2 is in view. You could see the P column and you know, all the important branches that come off the coroidal, the other meticulous strides. If you went further down and one for example, even you want to be absolutely sure that those can either be dissected free from the capsule and if they cannot. You should not really stress the situation because there are reports of pseudo aneurysms or false aneurysms, or even vascular injuries that result to aggressive dissection, those vantage points. So you were there, you saw it, it was adherence beyond, and you don't have an absolutely crystal clear viewpoint when you're doing craniopharyngioma surgery because you have a male corridor or so. If you see that you have adhesions and attachments that are going to be impossible to remove safely, the best thing, the wisest thing is to leave the thin capsule behind or some tumor behind and avoid stroke or perforated injuries.

- Thank you, Jim. And other adults, craniopharyngioma. I will review the details here 41 year old presented with the right sort of visual field deficits. And as you can see, this one is very cystic. Again, a adult craniopharyngioma. What are your thoughts looking at how to approach this lesion, knowing that it's sort of pointing more toward the left side?

- Yeah, so this is a predominantly cystic craniopharyngioma visual failure, which typically means that there is a focus point prechiasmatic, but not exclusively here because you can see on the sample of those go back quite some distance. But there is a solid nodule of tumor that's enhancing here, which you can see mostly on the left side. And I think for the case like this, you want to take into account where the visual impairment is, where your going to maximize your exposure so as not to injure the vision in the good eye, for example. So choosing all of these factors preoperatively, you can select for the best approach possible. I liked in your last case, the opportunity to go across court, as you said, because that really allows you to have a complete visibility. And that might be something that you're thinking about here. So coming in from the right side might be a very good approach for you here.

- Thank you, Jim. And that's what we thought. I think if we come here, you really have to make a turn and do a lot of retraction

- Exactly

- On this structure. So it's best even if his vision on the left was necessarily worse in this case, I think that the surgeon can protect that vision on the right side very well, but really the approach will be a lot safer from right to left. Obviously removal of the nodule is very important here. You just don't want to train with cyst. And would you agree with me that approaching this through a endonasal endoscopic, the cystic approach would be probably not a great wise idea because firstly, the teacher is on your way and secondly, the lesion is very high. I'm I might correct Jim?

- Yes, I would agree with you completely Aaron. However, there are reports and literature and I've certainly seen in presentations where endoscopically some neurosurgeon have use the approach even to retrieve very high nodules when operating on craniopharyngiomas. So while it has been done, it wouldn't be my preference. I think it would be potentially filled with some complications by using that approach. And again, this is a largely cystic lesion and by just draining the cyst alone is probably not going to be sufficient. You really have to try and get that nodule if you're going to be successful at controlling this particular craniopharynioma.

- Thank you Jim. And this is a right front of temporal craniotomy, temporal small salt, and scalp on the right. Again, we just, this is pterional right here. The value of really dissecting the nuance off of the lateral skin with wing and drilling that with on nuance. Usually that's fastest. And one nuance that I found very helpful Jim is really drilling this flat because if you, this is where your trajectory is right here. And if you can drill this very flat, thank you. It would help you to get more of an inferior spear view. You really don't have to put every patient through a orbital zygomatic craniotomy, and you will see momentarily for the sake of the residents, how we use the B1 without a foot plate and just go through all that gyration and make sure that is really as flat as you can get.

- I think that's a very important point Aaron. Every millimeter makes almost a mile of difference, and let's say exactly what you demonstrated in here. And I like this technique of using almost like a matchstick to flatten this out and really maximize your exposure. And there's no substitute or getting this. Every last millimeter of advantage throughout the case.

- Thank you and as you can see, there's not much temporal exposure, very minimal just to get the pterional exposed. And almost we got close to the par orbital, which is okay, as long as you keep the par orbital itself intact. And you can drill all the way to the superior orbital fissure to get a nice exposure. And what do you, this is again, a subfrontal approach. You don't need a temporal exposure. And after the doula is open, we put a tack up stitches right at the root of the rock rather than at the edges. And that also retracts as you can see and gives us a few extra millimeters, which can be lifesaving. And moving down, releasing CSF in this case, probably won't be useful because you're going to run into a big cyst. So opening the arachnoid membranes may not be very helpful here. So we're going to start opening the arachnoid membrane. On the left-handed surgeon. So it's always more difficult for left-hand surgeon to open the right side of fissure. And here I think trying to release as much CSF as I can before we start. And here you can see the cyst is somewhere here, but I'm moving more subfrontal anteriorly and I'm draining some CSF. So whatever you can do to drain CSF, it's important. Again, the relaxed brain is extremely critical in brain surgery. And again, no fixed retractors. We use only dynamic retraction to open the Sylvian fissure that you'll see momentarily, you can use fine duro forceps to open the fissure. How do you like opening the fissure Jim?

- Just like this is straight, teasing apart. The rack line is a very effective technique and it works extremely well in most circumstances. So it's, and then, I like sharp dissection, like using 11 blade actually to open the fissure by very carefully to something the arachnoid, opening, the arachnoid sharply, or you can do that very carefully under high magnification so as to avoid injury to the Sylvian vessels here, and as you know Aaron, some fissures way easier to split than others. And it just depends on a multitude of factors like disease, process itself, age of the patient, CSF spaces and so on. Some open up like a book, others close like a book. So it really depends on anatomy in unique anatomy for every patient.

- I want it to stress something. We do dissect from inside to outside. Like yesterday, you mentioned, You see, I went in and go and dissect here, I opened distally, stayed deep in the fissure and two branches. Sometimes you can do blind dissection and then you see move out. This inside, outside technique is so extremely important because the vessels really keep the place open for you. And then again, no fixed retractors whatsoever. And you see how the funnel load falls away from you when you do that in extension. And now you can appreciate the, again optic nerve retrochiasmatic location of this cystic craniopharyngioma. And now obviously you can start opening the capsule. This is poster to carotid artery, how aggressive are you to remove the capsule Jim?

- Well, that's a good question Aaron. This is a very extensive capsule and to chase it all over the place where you have system wall can be difficult. The problem with not removing all of it is that even though it didn't seem to have calcium, embedded in it throughout its entirety, it can still lead to occurrence. So if it's coming and you're able to mobilize the capsule as much as possible, it's probably best to try to take care of it because, otherwise even a small remnant of capsule unfortunately can potentially lead to recurrence. So you have to make that judgment interoperatively, how easy it's coming, how much of it you can safely remove. And certainly if there's thickness to the capsule and evidence of calcium de-position within the capsule that should go possible.

- And here is you can appreciate the dystall, the contralateral carotid artery, contralateral optic nerve. This is ipsilateral optic nerve and this is the nodule attached to hypothalamus. And again no retractors. You're using the gentle bipolar attraction to move, to look from inferior to superior and trying to dissect this nodule off of the optic nerve and then dissect the tumor off of the pituitary stalk if possible. And I think this is where you really need to be careful of the perforators. As you can see here, that's the one of the perforators on the contralateral side, this is one of the perforators sort of moving to the middleline. And it's key to be careful. This is the pituitary stalk. And as you can see, you can use sharp resection and dissect the tumor off of this stalk without necessarily taking the entire stalk and momentarily, you're going to see the nodule getting attached to the hypothalamus. Then I'm going to dissect by first, a gentle coagulation and then sharp dissection. Any nuances here Jim?

- Yeah, so I showed you a case where it was clearly infiltrating the stalk and we made the interoperative decision to resect the stalk. So that's something that you have to decide, and even if you leave the stalk behind and you've manipulated it a lot at the time of surgery by taking the craniopharyngioma away from it. Now the stalk may not function so well in any case afterwards. So what you're doing is I think preferable, which is identifying it, preserving it because anatomically that's what we should try to do, but we must also be cognizant of the fact that craniopharyngiomas also actually arise from here. And they may be intermingled to quite densely with the stalk itself and making a complete resection of the craniopharyngioma and leaving the stalk intact a very, very difficult task. So it looks like you've been able to do that. However here, that the capsule is coming away from it, and this would be preference if you can do this. What I should also mention is that not all cases are you able, for example, to identify the stalk, especially for large craniopharyngiomas, the stalk is either so flattened in a trophic as a result of size of the tumor that it's almost at times impossible to identify it. So there are certain cases when the stalk is not visible, as you're resecting the craniopharyngioma up to where at all possible, you should try to do so and preserve it.

- Thank you Jim. And momentarily a moment ago, you saw how it was attached to the hypothalamus. This is the capsule posterior to the carotid artery. I was relatively aggressive to remove the capsule here. I'm not sure that ultimately was a great decision as we'll see on the MRI. However, I think it's, if the surgeon can dissect it as to the best of his ability, it is important. I did leave a very tiny sheet of tumor over the hypothalamus. This is again to nodule and the content of craniopharyngioma that are being delivered anteriorly into the resection cavity. This is ipsilateral optic nerve that was very thinned out, carotid artery and working between the two and removing some of the contents of the nodule. Here is again, moving post. This is hypothalamus. This is contralateral optic nerve. And again, leaving just a tiny piece of sort of this membrane over the hypothalamus. Here is the hypothalamus, here's the tumor. This is the interface and avoiding pulling or aggressive burning of the nervous structures. Go ahead, Jim.

- Yeah, so I can see exactly where the plane is that you're developing there, but it is very adherent and you know, you've already been operating here, I'm sure for a couple of hours or so, but you really have to be on top of your game right there because that's where the rubber hits the road and where it's extremely important that you have the finest techniques to ensure that you don't carve into critical structures like the hypothalamus. And so you want to make sure that you've got good visibility throughout and that you keep the cyst wall in mind and that you don't unnecessarily harm a structure as important as the hypothalamus.

- And here's the stalk ipsilateral optic nerve, carotid artery. All the structures have been relatively well preserved. And this is I think the basilar artery, PCA and superior cerebellar artery. All being examined across the carotid artery and that's the brain stem. Really gives you a beautiful view. And here's that little membrane we left on that hypothalamus. You can see not using retractors. It really is nice to keep the brain as healthy as possible at the end of the operation. This operation went technically very well. And I thought, we did a really a great job, good closure, and he woke cup the patient after surgery with left-sided weakness for 24 hours. It was significant, I would say, three over five was strength. The strength and recovered right away. No speech difficulty, nothing else, left the ICU. And the postoperative MRI looked pretty nice, makes one to be very happy and brag about it. And here's the pituitary stalk. However, you can see there was an area of ischemia in the right thalamus and I felt like every perforator was preserved. What are your thoughts here, Jim? This patient didn't have any sequelae, but obviously we had a complication. So what do you think?

- Yeah, thanks Aaron. I mean, I see the lesion that you're talking about here. It's in the thalamus. I certainly looked at some of my cases in the past too MRI and at times, I am surprised that I'll see in some areas of ischemia. For some reason and fortunately, perhaps the lesions that I've seen in my own hands have been, although deep, they'd been in the anterior limb of the internal capsule for example, and it's pretty well tolerated there. It sounds like your patient made a very good recovery from this small amount of ischemia, but it is a concern. And it was one of the points that I mentioned during my video presentation was one of the absolute care you have to take with the microdissection of the very important perforators that are adherent at times to the capsule of the craniopharyngioma, because even the smallest branches can have important consequences to the patient and here you're demonstrating a small branch that likely against the thalamus, and thankfully did not have any long-lasting permanent sequelae. And I think we should all do and look very carefully at our MRI scans after surgery, including the profusion and diffusion weighted images, because we all stand to learn from them. And even if our patients wake up just fine, small areas of ischemia like this, we need to know about. So we continue to improve our skills at removing these tumors.

- And I cannot emphasize that surgical honesty is the key to anybody's success. And here is him doing really well, 48 hours afterwards, no pituitary dysfunction, a good outcome used with the permission of the patient while it could have for sure been different. But the surgeon has to be really very honest with themselves and do MRIs, 3D angiograms of the post-op aneurysm and realize that, although the patient wakes up, the aneurysm looked good, there could be a lot to be learned from watching your outcomes with detailed postoperative imaging.

- Thank you Aaron. So this was a very challenging case, a 13 year old male with headaches and Papilledema. And just by virtue of that presentation, you're dealing with a lesion that is going to either obstruct the CSF pathways and the third ventricle, which is the case here, or be a retroplasmatic craniopharyngioma. And the point I was making earlier about the coronal images is somewhat depicted here. And you can see that this very thick walled capsule of the craniopharyngioma actually has an attachment to adhere. So I'm going to just take a moment to pick up my laser pointer, because I guess I'm going to need that to demonstrate this a bit better. Here it is. So here's the demonstration of the attachment on the sidewall of the hypothalamus. Here, you can see more flare signal. I study these cases very, very intensely, and here's the actual image higher. And you can see with this projects up into the third ventricle causing obstruction of the CSF pathways. So here's the opposed St. Patient and we're demonstrating now the left optic nerve right optic nerve, chiasm. This is the left intracranial carotid artery using a cell frontal approach trans laminar terminalis. The laminar terminalis is going to be situated here as you'll see. A1 segment on this side, A1 on the other side, which you can see, and basically at the end of the procedure, just as you demonstrated in your cases, chiasm this is the big chiasmatic space. Here's the basilar artery. Posterior cerebral is on both sides. Superior cerebellar arteries. Brainstem is here A1, A2. A1 is here on both sides. We have both A1s that are able to show Lillequist is your friend. You only see Lillequist usually after the, or during the first operation, you have to go back in on a craniopharyngioma, such as this, the Lillequist membrane is no longer there to help protect you. So it's very important that you realize that you have one good shot to remove craniopharyngioma. I like the prechiasmatic cases I showed you. Here's a child. It's the same case, 1995. You can see here many years later, you can see that he's got some obesity that's developed from his presurgical state here. I would say this was mild to obesity, not as bad as some, but clearly as a result of removing deletion from the hypothalamus. There's another case, a 10 year old girl who has two year history of headaches, short stature, nocturnal polyuria, again, retrochiasmatic craniopharyngioma, coronal view, little bit of intensity here seen on the sidewall of the hypothalamus axial view shown here. And I'll take you through some of the surgical steps here and again, right optic nerve, left optic nerve, subfrontal approach. The olfactory nerve is shown here, prechiasmatic space. Here again, doing the dissection like widely of the arachnoid. We're able to get some length on the chiasm. We'll be showing the laminar terminalis shortly. There's the laminar terminalis you're seeing quite nicely. Right A1, left A1, the communicators here, laminar terminalis is coming into view beautifully just there. Now we've opened up into the laminar terminalis. We're working in front and behind that laminar terminalis as we're mobilizing and spread of extensive craniopharyngioma. Centripetal movements that are being shown here, as you demonstrated so nicely in taking care of here and here using mirrors to look in front of behind, underneath the optic tract. This is a blind corridor here for this approach. And so being sure that you remove the entire craniopharyngioma is you always important with either endoscopy or with mirrors as is shown here. And here's the view you can see now having to move a large portion of the lesion from the retrochiasmatic space. Here's the prechiasmatic space, long segment of A1 is being exposed for everyone to see here. And unlike the previous cases, I've shown this child. It took many years to develop, but she's definitely developed some obesity here. And I have permission to show her photograph here with the mother. And this is on a Christmas card that was sent to us afterwards. Obviously the family is delighted that she hasn't had recurrence now many, many years after the surgery. She's in fact graduated from SickKids, but she's definitely gained some weight as a result of the involvement of the hypothalamus and this being electrified as medic case. So other cases that I can show you here, for example, here's pre-op, post-op on the sagittal and the coronal images that you can see here. Nice for section this particular patient did not have the same degree of involvement at the hypothalamus that you can see. And so postoperatively did not have any hypothalamic issues, but it all comes down to the hypothalamus that you can see here. There is a grade zero on this paper by a Christian Saint rose and colleagues from Necker on pharma lad. You can see no involvement of the hypothalamus, some involvement of the hypothalamus, and extensive involvement of the hypothalamus going up to a great two level here, these authors would recommend that an experienced surgeon look after these cases. Whereas I think all neurosurgeons have the right to and should definitely be able to look after these types of cases where hypothalamus is not involved. Subjecting these patients in my opinion to a treatment such as radiation therapy or other types of non-operative therapy. Those those are not good ideas in my view. And here is that it's all written by Rick Boop about the pendulum that keeps swinging craniopharyngioma. Many things we still do not know about craniopharyngioma surgery, but we also don't know everything about radiation therapy, but the long-term effects of it are in many instances. So what is the future of craniopharyngioma surgery? Aaron, you asked me about endoscopic endonasal surgery, and here's an example of the series bike Assam. Here's a case that I had and showed a retrochiasmatic that we had resected completely in a nine-year-old male. And he went back to playing hockey, which she really enjoy to do that some three years later, he ended up with this occurrence that you can see here. And we asked ourselves what would be the best way of dealing with this. And the best way was with the endoscopic endonasal resection. So, Aaron, I don't know if you are able to show the video with this case, if it's available, that would be nice to show at this time. Beautiful, so here it is. Endoscopic, you can see the nice wide view that you have coming endoscopic. And initially here's the chiasm And now we're at the second sub chiasmatic to remove this craniopharyngioma, this small recurrence, and this all came out nicely in one piece. And I think because of its location, subchiasmatially redo several years after the initial tumor was moved. This was the best approach. Now we constructing this dural opening afterwards was a bit of a challenge, but we did so with an endoscopic approach using the nasal septal flap. And that's turned out to be very useful and is a way that we can minimize complications with craniopharyngioma surgery, such as CSF. Maybe we can both move back to the slides now, Aaron. And we'll conclude with just a few comments about endoscopic endonasal surgery and the view here by Ted sports and his group in a comment by an old field about the use of transnasal endoscopic surgery for craniopharyngioma. And here we are going to be discussing through the viewpoint of one of my mentors, Dr. Hoffman saying that only surgery is the best tool, but there are other options of course, for craniopharyngioma that need to be considered. Cyst aspiration is one technique. I showed the case previously, but we started with that. Here's a very interesting case of a large cystic craniopharyngioma without a mural nodule in which we decided to put in basically a cyst drainage therapy because there was nothing really to remove from the solid standpoint, here's the Ommaya reservoir that went in very nice result that you can see here only from cyst drainage. And that does not mean that this patient is cured of the tumor, but so far so good. Anyway, here's some other approaches neomycin alpha interferon isotopes can be utilized. And this is an approach that's been popularized by Kevin from Brazil. You can control craniopharyngiomas that are cystic using this technique. Three-year-old malware. I just basically showed a very large cystic craniopharyngioma. It's important when you're using this technique to make sure that the catheter stays in the cyst that there's no problem with leakage outside, especially if you're using bleomycin because it can be somewhat neurotoxic. Whereas the alpha interferon is not terribly toxic. Here's craniopharyngioma the St. Jude experience. Now talking about radiation therapy and here's the bottom line showing that in their experience, radiation therapy can be utilized with as good an experience as if they didn't demonstrate it with surgery. They have recommended limited surgery and the use of radio therapy because of the fear of some of the complications with more radical resection. So this is a very important point to make that some centers have chosen to use a more minimalistic approach for craniopharyngioma surgery. So stereotactic radiosurgery, the experience is accumulating and is getting better, but still a number of cases are small literature. One should really look at the series and here, they show that for at least the current craniopharyngioma offer residuals. Stereotactic radiosurgery is a very decent approach for small residuals as is shown in their hands. So very important finally to talk about the neuro sequelae of craniopharyngioma. Some of the neuropsychological effects, a lot of literature now is accumulating in the literature on such things as memory deficits for craniopharyngioma. Here's some of my cases, 10 cases where I looked at before and after surgery baseline and follow up, you can see that the patients, patients were pretty well served by the surgery that we performed without any evidence of major deterioration, perhaps some in the immediate verbal spheres, perhaps in overall some memory disturbance, but basically pretty well tolerated by patients with craniopharyngioma. So bottom line neurosurgical disease, in many cases, cystic therapy should be considered. Cystic craniopharyngioma radiation therapy can stabilize 75% percent of cases. Endoscopic endonasal neurosurgery, which we talked about is growing in popularity. So we'll be watching its impact on this disease and future studies and what we all do about the current craniopharyngioma remains a challenging problem to all of us so to this day. So if I showed that this panel of tumors to the audience, Aaron and I asked them which patient would have less likely sequelae of hypothalamic involvement left-hand panel or a right-hand panel, I think from the points that we talked about today, this is the case where you'd have to be very much on top of your game to remove this craniopharyngioma versus this one, because this is retrochiasmatic has involvement of the perforator system that we talked about much more chance of doing harm here than here, even using the best surgical techniques. So if you're going to tackle these particular tumors, you definitely have to know your anatomy, be very careful throughout the procedure so as to preserve all the structures, including the hypothalamus where possible and to know upfront that these are more challenging cases in my view than these prechiasmatic cases here. I think that concludes the discussion of these slides for craniopharyngioma surgery Aaron.

- And thank you, Jim. This was really spectacular, a great learning experience for me at the same time. If you say there are three most technical pearls in craniopharyngioma surgery, both in selection of patients and intraoperative techniques, what would you say those are to the young neurosurgeons?

- So I would definitely make a point at first of studying the preoperative images Aaron, I think there's no substitute for trying to classify craniopharyngioma into one of its counterparts, sellar, retrosellar, or prechiasmatic. Really important to try to do that a priority because that will determine aggressivity at surgery and what the potential complications could be. So that's point number one. Point number two that I think is really important as a technical nuance is opening up the arachnoid in the cystic just as you demonstrated in your case, because that allows for adequate brain retraction to be minimized in terms of any type of brain retraction injury. It also maximizes your exposure that you're going to get. So take time to liberate the cisterns drain CSF, open the arachnoid widely across your entire field, across the entire chiasm, going from left optic nerve, right optic nerve, making sure that you can fall out even along the middle cerebral artery, temporal lobe area, all of those systems need to be open widely, and that will maximize your exposure. And then finally, the third teaching point that's critically important and one that is really hard to teach is the centripetal movement that you need to mobilize the capsule. Let's say for a retrochiasmatic craniopharyngioma, because that is a critical step in itself to remove craniopharyngioma in this location, but also offers you the opportunity then to take hold of the capsule and use very gentle and progressive traction. To liberate once you've done the dissection, the fragments of craniopharyngioma that will come out that will open up other corridors and avenues for you to be successful in removing the tumor completely.

- Thank you, Jim. Thanks again, as always it's been great support of this program. I know would have not been possible without all your support. Thanks again.

- Thank you very much Aaron, nice time.

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