So I guess we'll just carry on. So we're going to move on to a point-counterpoint. And we're going to start off with pediatric skull base surgery, expanded endonasal approaches. And then we're going to counter with open approaches. So the first speaker is Dr. Tyler Cabrera. And we think the mouse works. We'll find out. Thank you all for this opportunity. I'm looking forward to this. To preface this, Jerry Oakes had a symposium. And at the end of the symposium, he had one of the group show a video of a craniopharyngioma that had been taken out endonasally. And Jerry thought I was crazy when I was a fellow and ever suggested taking them out endonasally. And he turned to me and asked me when the last time was I did an open craniotomy for a cranio. And I truthfully answered, never. But what I really want to stress today is that it is not that endoscopic surgery has replaced open skull base surgery. And I hope that I'm going to convey that to some degree. But that the endoscope has become an incredibly advantageous tool to all of us in the field of skull base surgery, and particularly in the field of pediatrics. When I teach courses for adults, we talk about the key principles in skull base in children. And one of the things that I think I have learned in the time I've been doing this, there are times when there are lesions we see in kids that may very well be benign lesions. And that although my adult colleagues might want to run out and take them out right away, sometimes it is better to watch benign lesions rather than to put someone through a big surgery. I am also a strong advocate of a team approach for skull base surgery. And we'll talk a little bit about that as we go along. We do occasionally add sublabial approaches, which means I need my ENT counterparts with me. One of the big things that I think I was criticized on early on was that the adult skull base endoscopic surgeons had these giant sinuses to go through, and it made life really easy. But I'm a kid who grew up in the technology world, and so image guidance, I think, has really helped us with that. Hemostasis is a big deal. The first time I, one of the first big tumors we did where we had to drill out a lot of the clivus, we stopped the surgery because we'd lost too much blood. That has never happened again since that because we are incredibly meticulous with our blood loss. When we are doing large bloody lesions like juvenile nasal angiofibromas, we do conscientiously track blood volume to make sure that we're not getting to a point where we are dangerous. We try to stop at no more than a 50% blood loss volume. I had some British surgeons watching us one day who could not believe we went that far. We will also stage stabilization sometimes, rather than continuing late into the night. Early on in my career, I did a couple of occipital cervical fusions at 2 AM, which I try not to do anymore. Septal flaps, which were, or vascular flaps, were a big game changer in the adult world. One of the problems in children is until they're over the age of 14, sometimes the anatomy is just such that those flaps tend to be short. And I think the biggest criticism of the endonasal approaches is certainly the high rate of CSF leak, and we'll talk a little bit about that. I sort of want to highlight this tool with a couple of cases. This was a 19-month-old who presented with hemorrhagic papilledema. She was emergently shunted at an outside hospital and told there that she must have emergency surgery or she was going to die. The family opted to drive up the street to our hospital. There was some history of hyperphagia. Her hormones were somewhat intact, but low growth hormone, and this was her imaging. So, a show of hands, how many people would approach this from an open approach, and how many people would approach this from an endoscopic approach? Okay. So we had a discussion with the family, and the considerations, obviously, there was no sphenoid sinus in this 19-month-old, and she's very tiny. There's this huge anterior cyst. She had some preserved pituitary function, and there was a question of whether or not we would be able to preserve any of that. I will be honest. The conversation we had with this family was, yes, we can go and take out that solid component from an endonasal approach, but I don't know what's going to happen with that big, giant cystic component. So here is her postoperative imaging. So you can see that, obviously, the cyst did not come all the way down. Let's see if I can point at this. This funny thing here, this is actually part of our reconstruction of the skull base. That's a piece of gel film that is floating in her CSF space. You can see that the solid component is gone, but you'll also see that there is some enhancing wall up in the third ventricle. We routinely do not strip the walls of the third ventricle, so that was what I would expect. We ended up as anticipated that she was panhypopit. This was a 19-month-old. Taking packing out of the nose and having to do that and potentially treat crust, these kids often end up with repeat trips to the OR unless they are very good. She actually was able to do some of her stuff as at the bedside. Adjuvant therapy is always a question. So I know in many practices, people will do subtotal or near-total resections followed by radiation. We have been a home of gamma knife for many years, and if there's not a target, they don't want to treat with radiation. We have been looking at, in some cases, sending kids for proton beam also. In this case, we did not have any additional adjuvant therapy, but in her six months, she still had not collapsed the cyst. So again, tools, which, what do you do? This is not a discussion about all the options we have. The cyst child actually got P32, and you can see there on the right-hand side that we had complete collapse of that cyst after we instilled P32, and you can see that the enhancing rim that was left in the third ventricle is now gone. She's now about four years out without any evidence of recurrence. One of the things that we have always believed is that coming from an endonasal approach gives us excellent access and visualization of the optic chiasm. This is the view from underneath, the superior hypothesial vessels giving off the branches to the optic chiasm. And after saying this at meetings, we finally went ahead and looked at all of our craniopharyngiomas, and what we have found is that in about 88% of our patients, we actually have visual improvement, and we only had 4% of a decrement in vision in our patients. Now, this looked at both our adult patients and our pediatric patients. If we pulled out just the pediatric patients, which was about a fifth of that study, our numbers were very similar to that. If we look at that compared to some of the more modern large series, where the reports of improvement range from about 35 to 50%, and the deterioration varies somewhere between six and 15%, so certainly from a visual outcome standpoint, I would say that the endoscopic approach for craniopharyngiomas has been an effective tool. How low can you go? Can we abandon transoral approaches? This was a five-year-old who had a biopsy done during a TNA that turned out to be a chordoma. You can see that this extends well down behind the DENS. Certainly in our hands, we have found that we can get well below the synchondrosis. We can actually get down below the base of the C2, and we did consider this for a possible endonasal approach. It also had an intradural component, so we knew we were probably gonna end up with a large dural resection. Do you do a nasal flap? Do you just up front decide you're gonna do something else? What do you tell the families about expectations? And one of the things that we certainly talked about in this patient, given how low it came, was the concern for a possible CSF leak. We were able to get a complete resection. We were able to remove the intradural component, but that flap did need to come all the way down to the base of C2. So if you do get a CSF leak in that setting, what are your options? We've certainly looked at the possibility of doing repositioning of flaps. You can use fasciolata. You can use a temporal parietal flap where you bring in the paracranium from the side along with the temporalis. The other thing that we have looked at in these children is using paracranial flaps. So the paracranial flaps for these low defects that come all the way down to C2 are wonderful in these very young children. And you can see here, this is sort of the up close view, the paracranial flap has come in through a slot at the top of the nose through the frontal sinus and then has draped down. You can see on the pulled back view that we can really bring this down. We can actually probably get them down to about C3. And this has been a very effective way of treating these patients and being a solution for CSF leaks. So one of our ENT colleagues decided to take a look at our CSF leaks. This was specifically in our pediatric patients. And we looked at a total of 55 patients who underwent 70 surgeries. The majority of those patients, we do have active CSF egress during the time of surgery. And when we looked at our post-op CSF leak, this was all comers, so this is craniopharyngiomas, chordomas, purely cellar lesions and a variety of other lesions. We had a 23% CSF leak, requiring some sort of additional intervention. Chordomas by far were the worst with a 36% CSF leak. That really reflects data that goes back before we started being able to, using these paracranial flaps, and I'll be interested to see where we go with that. The other big question that people ask is, what is the morbidity to the facial structures? And we've now been doing this long enough that we've been able to go back and look at this. And so the numbers we've looked at are cellar denasion, cellar nasion mandible, cellar nasion maxilla. And these are based off of some standardized studies that have been done in mid-face growth in the ENT literature. If we look at, we used our younger children, so under seven, and these are the ones where we saw some changes in the older children, they really matched up with the normative data. In the younger children, they all had a short cellar-to-nasion distance, pre-op and post-op, and it didn't matter much on the disease type, but that was the overall. And what we saw in the post-op changes for these patients, that really the only place that changed was the cellar-nasion mandible angles. And what that is, is that those patients, although they were not way off from normative values, that they had sort of disproportionate growth of the mandible compared to the mid-face. But really, when we went back and looked at these, we are not seeing any sort of significant disfiguration. I said this was a tool. So there are times where we have to consider combined approaches. This was a 10-year-old with a large JNA. You can see that there was significant extension up into the middle fossa. So how do we approach something like this? We now pre-embolize all of our juvenile niozolangiofibromas, but you could see, even post-embolization, we had some significant feeders to this. We needed to figure out how we were gonna approach that middle fossa component, and we chose to do an open approach that approached both the sub-temporal and the middle fossa. We knew we had significant vascularity. We actually did intraoperative onyx embolization through that open approach, because that exposed a component of the tumor that was not embolized already. And how many surgeries do you do? This child actually underwent three surgeries, and you can see the blood loss was significant for all of these surgeries. But in our post-op imaging, where we went from this large component, much smaller component, and then at two and a half years, that's been persistent. I think one of the other things that is important is, are we actually making a difference from these minimally invasive procedures? We recently looked at cost data for our cases. Now, this takes all cases, so this may include some patients that had come back for recurrent surgery, but our average length of stays were longest in our patients who had juvenile, longest in our chordomas, which were five days. They were between three and four days for the other big ones, which is the juvenile nasal angiofibromas and the craniopharyngiomas. And if we looked at our overall operative costs, they were comparable. Now, one of the things is, we really wanted to do this and go back and compare this to historical data. One, unfortunately, we did not have good historical data for the costs, and we didn't have a lot of recent open craniotomies to do the comparison. So all I can do is take these as single numbers and at least length of stay, compare them historically, which are good. So we certainly feel like we see less morbidity from cranial nerves, brain retraction, and we have excellent cosmetic outcomes. The acceptance with families has been very good. We have now fairly, we have well confirmed that we're seeing less or minimal disruption of growth centers. Our recoveries are shorter. We also find that this can be a wonderful tool when you're doing repeat surgery. We have a fair number of repeat surgeries that are sent to us, and perhaps there's a lower biological cost than an open craniotomy. The disadvantages continue to be that our patients are small and that we can have problems with post-op care, and certainly, I think the biggest thing remains is the problem with our CSF leaks and looking to reduce that. We are a huge believer in the team approach, though we have chosen to use a pediatric neurosurgeon and our adult skull-based surgeons because of the large volume that they do. We do these surgeries in the pediatric hospital, and then they are taken care of by the pediatric neurosurgery team, and we have experimented with different models and felt that that has been the best option, and I would say that one of the things that we feel very strongly about is the team needs to have the skills to do open surgery because there are times when a tumor does not meet the requirements for an endoscopic approach. Thank you very much. I'd like to thank my adult partners, Dr. Gardner-Sneiderman, Fernandez-Miranda, and Dr. Wang. Thank you.

pediatric skull base surgery

endonasal approaches

endoscopic surgery

nasal flaps

CSF leaks