Thank you. Next in our point counterpoint, we have Pediatric Skull Base Surgery Open Approaches by Dr. Levy. Thank you for allowing me to provide the counterpoint. The talk should really be called Skull Base versus Extended Endonasal Approaches because that's really the gist of what I'm going to be talking about. Really kind of address a couple of questions. Who are the patients that are eligible for Skull Base versus endoscopic procedures? Who are the surgeons that are performing these procedures? What pathology are we dealing with? What are the consequences of our action, whether it be skull base or endoscopic? Where anatomically are these procedures best utilized? And when are they best utilized? A number of years ago, there was a paper that came out that defined training levels for endonasal skull base surgery. And the basic levels were not difficult to reach. Basically, a competent ENT team felt comfortable with vascularized flaps, a neurosurgery team familiar with endoscopy, transnasal approaches, which is basically all of us. What was concerning is the advanced levels, which really demanded comfort with intradural and extradural skull base surgery, comfort with vascular surgery, and comfort with craniopharyngioma surgery. And this really puts it in a whole different plane. So who? There's no doubt there's a disparity in our training of residents, whether it be skull base surgery, vascular surgery, endoscopy, or as we're all aware of, pediatric neurosurgery. What's more problematic is from the time we're fellows moving on, we become pediatric neurosurgeons because we don't necessarily have an interest in skull base surgery. We don't necessarily have an interest in vascular neurosurgery. And my worry is that as we move farther away from that training in our fellowships, do we become less competent at what we do? And that begs the question, can we succeed in performing these procedures in isolation of a complete understanding of the anatomy? Or basically, are we wily coyote, oblivious to the fact of what lies below us, given the semblance of safety of a cloud? When you look at pathology, this is two large adult series with our series, and basically similar with pituitary tumors and chordomas, we had an overabundance of craniopharyngioma, difference in encephaloceles, and we had no meningiomas in our surgery. Complications, this was the largest series, adult series I could find. Once again, majority of pituitary adenomas, meningiomas. The question is, as pediatric neurosurgeons, is a CSF leak rate following vascularized flap of 6% acceptable? Is a 2% chance of a permanent neurologic deficit acceptable? Is a mortality of 1% acceptable in our populations? And how does that compare with our experience doing skull base surgery? Where I have a very simplified approach that I utilize in training my residents and fellows to skull base surgery, basically from the bottom for far lateral, basically extreme lateral, infracondylar transtubercular approaches, middle fossa approaches, you combine them with the leach, you get a combined approach, orbitozygomatic approaches, and subfrontal plus or minus transbasal approaches. For far lateral, I really prefer this with anything that's in the angle, especially large tumors that need a complete resection, such as ependymoma. Even smaller tumors that may lie in the jugular foramen, it's the activity of displacing the vertebral artery laterally, with or without the plexus, the dural opening that's very specific to get you to the jugular tubercle, which you need to take down, that there is no satisfactory option using an endoscope, especially if you need a complete resection. For combined procedures, this is a young boy that I operated on with a malignant meningioma from Russia, took a combined patrosal approach, was able to get a good resection, the complication is a significant hemiparesis and facial abnormalities post-operatively. Infratemporal approaches, there really is no adjunct for endoscopy, and so I won't discuss these because I don't see that there's an endoscopic approach to be useful for these type of tumors. And lastly, orbitozygomatic approaches, which there is no doubt that I've overused in the past, I was kind of like a hammer walking around looking for a nail for a period of time. I think that these are appropriate approaches for these large craniopharyngiomas or other tumors where you have a lot of lateralization, and I am not good enough with an endoscope to approach these type of tumors, or this kid that had solid ancestor components with posterior displacement, lateralized displacement, and this is another case that I did through an orbitozygomatic approach, and I don't see, really, that there's an equivalent endoscopic approach for this given the solid ancestor components. Also, I think that transcavernous approaches for primary cavernous sinus masses are the only way to go because I don't see a way of really working in a small cavernous sinus with an endoscope. Lastly, subfrontal and subfrontal transbasal procedure, which, for the grace of God, have really been knocked off by transnasal endoscopy. These are barbaric and really aggressive approaches. A lot of us used to do a lot of them, and it's very, very rare that I'll utilize these approaches for many, many reasons. It's funny because when I think back, the way I would have approached this lesion is through a subfrontal approach. Now, this can be cured with an endoscope quite easily. There are still some cases that I do do a subfrontal with or without transbasal approach, and once again, don't feel comfortable doing it isolated with an endoscope. So, basically, this puts us in the realm of transnasal surgery. So the question is, are you gonna stay directly in the midline, or are you gonna head lateral? The problem with the lateral approaches off of the midline is the anatomy's complex and be somewhat confounding. The pathology can also disrupt the anatomy, making it particularly dangerous. The corridor's small, and if you need an aggressive resection or a total resection, this isn't the way to do it. You can get to the cavernous sinus. You can get to Meikle's cave. You can get to the petrous apex. You can get to Glasscock's canal and below the petrous portion of the internal carotid artery, but once again, this is a difficult approach. Your visualization is not optimal, and it's something that I don't feel comfortable doing, and I've unfortunately learned the hard way. So when you're looking at the midline, you're basically talking in transcribiform to transoral approaches, and comparatively speaking, endoscopy's minimally invasive. Skull base is maximally invasive. The essential goal of both is one, a direct anatomical route to the lesion, avoiding any kind of neurovascular structures, and minimal to no brain retraction, which is really supposed to be the reason we do aggressive skull base procedures. Both are compromised by danger of CSF leaks and meningitis, the duration of the procedures, which can be long, blood loss, and morbidity, which can be quite extensive in both. It's my feeling that it's not the approach that you take, but it's the pathology and where you end up that tends to be most problematic. This is a contemporary series with the two bottom series being pediatric, basically, of what we're seeing. You can't really look at resection rates because it's apples to oranges. These are different series, some pure craniopharyngiomas, some not. Different elements of safety that are anticipated, so you can't really look at that for any discussion, but are we happy with leak rates that range from nine to 30% in the literature? Are we happy with the infection rates, the death rates, the brainstem injuries, and the complications from pure endoscopic approaches we're seeing in the literature? And I'm not certain that I am yet. So when do we use pure endoscopic approaches, or when do we combine them with open approaches? In our learning to do this, because we were latecomers to this, we kind of waited until everybody else did it, got a sense of what we could and couldn't do, and then learned from everybody else, so there's no innovation on my part. So we started small, pituitary tumors, and as we moved larger, we tended to go with larger and larger cystic masses, then felt more comfortable with solid masses, and then combination of cystic and solid masses, and this is a craniopharyngioma that we did endoscopically because there's not a lot of posterior displacement, and there's not a lot of lateralization of this tumor. But once again, that's a far cry from these type of tumors, which once again, I'd use an orbital zygomatic approach. Combined approaches. This is fibrosarcoma in a six-month-old. Started with a craniotomy for resection of the intracranial portion, staged with an endoscopic transnasal approach, we were able to remove the nasal component, and this child had a remarkable outcome. Dealing with clivus chordoma. Our approach is basically transoral, transnasal, followed by far lateral approaches. In this case, also needed a fusion. This is another case where once again, it's this posterior component that I use an elite approach on because I just can't get there safely from the front, whether it be through the nose or through the mouth. We use adjuvant therapy of proton beam, so we need to have room away from significant structures, so the best way for me to get there is through a far lateral approach. So in conclusion, endoscopic approaches are viable options and essentially replace most midline approaches to the skull base. I don't believe they're comparable at this point to orbital zygomatic, elite middle foster, combined pterosal approaches. I think surgeons need to excel at both, and I think Derek Bruce's idea that we need to stay contemporary and have a mastery of both makes it so we'll do the best job with these. From my first nine years of practice, I was also the number two skull base and vascular guy at UCLA County Hospital, so I was able to utilize that, which has kind of brought me to this point, and the fact that I do enjoy skull base and vascular. What is the goal for the tumors? Is it complete resection, subtotal resection, biopsy, decompression? I think you need to have that in mind when you approach these lesions, no matter whether it's through an endoscope or a skull base procedure. Is lesion amenable to the approach? Is this the correct approach? But I think the most important thing is when the outcomes are comparable, you need to take the approach you're most familiar with and you feel safest with, and that's where you're gonna have the best results, because it's much better to get a subtotal resection and stage that procedure than hurt somebody, a child, for the next 90 years, and that's not a worthwhile exchange. It's really minimized the use for subfrontal transbasal or transfacial approaches, and I'm really looking forward to endoscopy basically making most of the skull base approaches we take, which are really barbaric, go away, because that's really what needs to be the next step. This is a young man, very, very aggressive transfacial skull base approach for this tumor. We had a great-looking MRI, and he died from the procedure three weeks later. Thank you.

pediatric skull base surgery

endoscopic approaches

training levels

tumors

traditional surgical approaches