Endoscopic Approaches to Pediatric Epilepsy Surgery: Pediatric Endoscopic...

We'll move on to uh the next talk, which is by Doctor Sandy Lamb. Um, we wanna thank Doctor Lamb for joining us and discussing a topic that, uh, is very different than the rest of the topics today, and, and we're all very, very interested in hearing her talk on the use of. Of uh pediatric neuroendoscopy or the use of endoscopy in pediatric epilepsy surgery. Um, Dr. Sandy Lamb comes to us from Texas Children's where she's the director of pediatric cerebrovascular neurosurgery and um very much looking forward to your talk. Thanks, Sandy, for joining us. Thank you very much for inviting me. Um, so sharing the screen. Perfect. All right. Um, so, yes, this is, uh, we're gonna switch gears a little bit, um, and talk about, um, the development of endoscopic approaches to, to epilepsy surgery. So, this is a very much a story that, that I wanna share with everybody. Um, so, at Texas Children's, we have a, a quite a big pediatric epilepsy surgery program. Um, and a little bit of background, uh, for epilepsy surgery, uh, especially in children, um, there, we know that there are detrimental effects on the developing brain, um, especially in the, uh, setting of recurrent seizures and, uh, long-term anti-epileptic drug therapy. So, when surgery can be performed safely, uh, we want to Deploy that early. So our goals are seizure freedom or at least reduction in the seizure burden. There are seizure-related injuries. There's exposure to medications, and there's a lot of improvements in quality of life for the children and the parents that can be at stake. So we also take advantage of the plasticity of the developing nervous system. So, we know the International League Against Epilepsy has a consensus for recommending early surgical intervention, um, pretty much when, when it's safe to do so, um, because of the, um, reasons that I, I explained before. So, we have kind of a spectrum of options, right? So, we have maximally invasive approaches, um, and that is with a, a full open craniotomy that gives the surgeons very good control and very good visualization, especially when a lot of these children have abnormal anatomy. Um, there is associated morbidity because these are big surgeries. Now, minimally. Invasive approaches have been very vogue and have been explored very intensively of late, um, but we have to make sure that when we want to kind of push the envelope and do this more minimally invasively, that we can achieve a complete disconnection and can offer outcomes that are similar to our tried and true, maximally invasive approaches. So, um, there's a spectrum of types of epilepsy surgeries that we can offer to children, um, and I will kind of selectively talk about a, a few that we can, um, think about. Uh, a different type of approach. So, in kind of for full disclosure, uh, at Texas Children's, um, one of my colleagues, Dan Curry, has been a, um, a pioneer in stereotactic laser ablation. So there's very much a minimally invasive focus already in in terms of epilepsy surgery. So, when you think about disconnected. Versus resective surgeries and epilepsy surgery. Um, on the screen, you'll see there's the disconnective surgery type spectrum is hypothalamic hematomas or corpus callisotomies or hemispherectomies. Um, in terms of techniques for kind of resecting or, or destroying, um, lesions, uh, we have craniotomy, endoscopic, um, Uh, focused ultrasound, uh, stereotactic radiosurgery, or, uh, stereotactic ablation. Now, um, at TCH, uh, I, I really can't talk about endoscopic approaches to hypothalamic hemaratoma, um, because, uh, it, it's a pretty robust practice, um, here for stereotactic ablation for hematoma. So I won't be talking about endoscopic approaches for that. Um, and this is a, a, a center that is a very pro, um, ablation. So, in, in light of, um, the big experience for using the, the laser, why, why am I talking about endoscopy? So, let's kind of talk about our, our focus on minimally invasive, uh, surgery first. So we have done cost comparisons, um, so for laser versus open surgery. For hamartomas, um, we don't have the open experience here, but when we use national databases for, uh, what open surgery for hamartomas, um, uh, would have in terms of a hospitalization for surgery, we can compare that versus, um, what we've been doing here with laser ablation, and we can show that a minimally invasive approach, uh, is, is, um, better or a little bit less in terms of, uh, utilization. So we've developed minimally invasive pathways for epilepsy surgery, for stereo EEG and laser ablation, but then we realized that, you know, when you have a hammer, not everything is a nail. Um, we did, um, corpus callisotomies with the laser, uh, kind of trying to push this technique, and we realized that maybe it wasn't really better than open surgery. So then we realized maybe there's a role for something else, um, and that we should always be examining what we do, so that, uh, we can. And try to see, well, our experience with open surgery, our experience with laser surgery, we always try to do the right surgery for the right patient. So, is there a role for something else? And this is where the endoscopic surgery program came into existence for pediatric epilepsy surgery at TCH. So when we looked at corpus. Callicottomies. We looked at about 10 callisotomies, um, for laser ablation versus open craniotomy. We realized that there's actually no difference in length of stay or discharge destination. Uh, most of the children needed to go to rehab, and with the laser ablation, actually, um, 3 of these children needed re-operations and 1 even had a transient hemiparesis. So there was no clear benefit of the laser ablation over the open approach, but um with the goal of thinking about minimal access, but still being able to do a disconnective surgery safely and completely without having the children be on a a high dose steroids for a long time, or having um the need for re-operation and having An incomplete disconnection, is there something else that we can offer? So when you look at, um, laser ablation for, uh, for corpus callisotomy, you'll see that you actually need multiple trajectories because the anatomy of the corpus callosum kind of dictates, um, how you would approach it with these kind of straight line, uh, catheters. So when you look at. How you can do the laser ablation, um, it's a little bit hard to control these straight lines with, with these, um, with curvy anatomy, essentially. So, um, this is how a transient hemiparesis can occur. So, when we look at that, we realize, well, this, this, um, would actually be a role for endoscopy, so that we can try to minimize the surgical corridor, uh, or the surgical access, but still be able to do the, the surgery. So, when you look at the, the evolution of endoscopy, um, corpus callisotomy has been described, uh, with cadaveric studies first, and then, uh, corpus callisodtomy, uh, series described by some groups. So, Matt Smith in Saint Louis, uh, just did a great technical note and series. And you can see that there are, there are different um types of ways to tackle this, and I, I like how Doctor Grant talked about, um, uh, endoscopic controlled or endoscopic assisted. So, we opted for the endoscopic assisted way, uh, almost like a trans nasal transhenoidal type of surgery where you can use three hands, um, and, uh, actually have that control. So, the learning curve is, is a little bit less, um, because it, it does give you very good visualization and, uh, you can use, you know, the surgeon can use, uh, both hands as if, um, under a microscope. So, navigation is really important. We use a straight, uh, sinoscope, uh, that gives very good lighting and, uh, very good visualization. So, when we do this with the navigation, we actually navigate with the, uh, the straight endoscope, so we can navigate in real time. Um, and then the steps described, um, uh, it's actually just like you would do in, in an open surgery. So it would be an intrahemispheric approach. Uh, you go to the corpus callosum. Um, and you actually just do a, a white matter, um, disconnection. You can use a Cusa or a controllable suction. Uh, your landmarks are your pericallossals. You want to see your ACAs, um, and then you want to see the rostrum, and then I'll, um, if you're doing a, uh, complete corpus callistotomy, you would go all the way back to the splenium. So, um, here's an operative video, uh. If I can Uh, so, it's a, a short, uh, kind of quick, uh, edits to show you the highlights of the steps. So you would go intrahemispheric, if you look for the corpus callosum. And as you can see, this is with the endoscope, but it, it's actually very natural, um, for the surgeon, um, you know, I, I can actually use the bipolar and the controllable suction, um, and then, um, now I can actually look, uh, for my landmarks, uh, anteriorly. And then, uh, we're actually gonna take a cruise uh around from the, uh, anterior portion of the corpus callosum. You'll see the faults, uh, you'll see the pericallossals and the landmarks we were talking about, and then all the way back to, uh, where the splenium was, um, which is now gone. Um, so you can actually do a very nice, uh, subpeal resection, just like you would do a normal, um, open epilepsy surgery. Uh, and, uh, and do a complete corpus callisotomy. So, uh, when you look at the, uh, incision, uh, it's, um, paramedian, um, and, uh, uh, coronal and precoronal. So, and then you can also look at your postoperative DTI, uh, especially when we were first starting out, uh, we wanted to look at this to confirm that we did a disconnection well. So, looking at, at, um, well, if we can do corpus callisotomy, um, well, uh, is there a role for, for applying the endoscope for, for other types of surgeries that we would normally do with a traditional open craniotomy? Now, the hemisphorectomy has been described with endoscopic assisted approaches by two groups. Um, and if you look at the evolution of techniques, uh, it's over time for just hemisphorectomy, it's gone from anatomical. To functional, um, a functional hemispherectomy to a functional hemispherotomy, and, um, there are, uh, approaches where you resect a lot of tissue or more kind of res uh disconnective approaches, uh, from laterally or from paramedian vertically. So, um, this is kind of what we developed, uh, here over time is when we looked at our traditional approach to, um, looking at the literature and actually doing a lot of work in the cadaver lab to figure out what is safe, what we can access, what we can see with the endoscope, um, is actually, uh, pictured here where we, uh, use a paramedian, uh, vertical approach with one burr hole. So, when you look at a hemispherectomy, like what are the required steps, right? So when you think about, well, how are we gonna deploy this, this endoscopic approach. So, in a big open approach, um, you can do a question mark incision or a T-shaped incision, uh, but then you would actually, um, Uh, need to actually get into the ventricles so that you can reach your corpus callosum, your hippocampus, your tail of your hippocampus, actually do a white matter disconnection, uh, do insular cuts and do a frontal basal disconnection. So, uh, cadaver studies and kind of proof of concept studies, uh, were described by Al Cohen, uh, with two burr holes, frontal and occipital. So, the frontal approach gives you a view, uh, pretty much at the foramen of Monroe, and occipital, uh, into the atrium gives you a, uh, a view of your temporal horn. So that when I tried to do that in the cadaver lab, it didn't, it didn't make ergonomic sense to um To me, in terms of uh how I could reach the temporal horn and what I would do to the hippocampus from a kind of parallel straight on look, if I had an occipital burr hole. Now, when I looked at how um Willemir would describe a vertical um permedian approach hemispherectomy or a disconnection, that actually seemed a lot more accessible in terms of uh minimizing the access corridor and applying the endoscope. And this is how the two previous groups that have described endoscopic hemispherectomy uh have approached it. So, Doctor Sood and Doctor Chandra. Um, have described a small series of, uh, applying endoscopic approaches, uh, both callisotomies and hemispherectomies, and described basically the steps that are, um, uh, that are needed, uh, to, to achieve a full disconnection. So when we went to our cadaver lab, um, we, we kind of developed our, uh, a fallback plan. Uh, which is how do you actually reach the temporal horn, uh, from up top, if there's tissue in the way or if you can't see, or if you can't quite navigate there, um, or you just don't have enough control. So you can always convert to an, an open approach, um, and, and turn a full craniotomy, or, um, actually approach through a middle temporal gyrus. So we worked that out in the lab, and that seemed to be a good fallback for us to be able to get to that area. Um, I will show a video, uh, of, of how we apply this on patients now, which we've been able to actually do with one burr hole. Uh, this is what we saw in the cadaver lab first. So we did an intrahemispheric approach. We'd go to the corpus callosum, and then we'd get into the, uh, body of the lateral ventricle, and then be able to see the anterior portion of the corpus callosum and then see all the way into the splenium. And then actually be able to look into the ventricle and look at our ventricular landmarks, look at the choroid plexus, uh, be able to look into the atrium, and then, um, look into the temporal horn after we do an insular cut, and then actually be able to do a hippocampectomy, uh, which was not previously described in the, uh, in the published, um, small series. So the frontal basal disconnection is a little bit tricky in terms of um you're inside the ventricle and you're trying to figure out, um, you know, how to actually, you know, do a full disconnection, and then also to make the uh insular cuts. So you're looking at your um anatomy from inside the ventricle, um, looking at the foramen of Monroe and where your caudate is. So we were able to do this in the cadaver lab. So then we applied this to pretty carefully selected patients, and I, I think case selection is very important, um, when, when trying to develop new techniques, and I totally agree with um, the previous speakers and Doctor Proctor, which is, um, that you have to have, uh, a lot of experience and comfort with the open surgeries and the full armamentarium before thinking about trying to minimize your access corridor. Um, and to be able to, um, uh, be very familiar with the anatomy. So, uh, we use neuron navigation, and, uh, you can see our scan for our first patient actually, uh, was a post-stroke, um, uh, epilepsy patient. So there was already a lot of, uh, a lot of room. So this was actually a very good, uh, first patient for us. Um, So using the neuron navigation, um, you can see that the yellow is actually with our straight endoscope and then the green is where we would use our pointer. It, uh, also a paramedian incision. Um, we use the, the pins in this way so that we could still draw a question mark incision, uh, in case we had to convert to open and also, uh, leave that area, uh, for a second burr hole if we needed to do a middle temporal gyrus approach. So here is our operative video. Uh. This is a a a uh another patient who actually had a little bit more brain tissue. Um, so we, uh, would get to the corpus callosum first, uh, and then get to the anterior portion. We're looking for the ACA's doing a subpeal uh dissection. We're next to the ACAs and working on a frontal basal disconnection there. Uh, this is a very nice view with the endoscope and being able to use two hands with the bipolar and de suction. Um, and then you can see we can use different types of, uh, instruments in here. This is posteriorly looking at the splenium, um, and then, uh, a good way of, um, having that floppy brain, uh, be a little bit out of the way is to use a cotton ball to help do a little bit of retraction. And actually looking into the temporal horn, uh, we'd have to be familiar with the intraventricular anatomy and then go lateral to the caudate, uh, confirming with the neuronnavigation and also knowing that that's the described way, uh, of the lum as well. And that's looking into the temple horn. You can see the ependea and looking at the hippocampus. This is with the hippocampus gone. Um, you can see that we, we can actually do a very nice appeal, um, resection here, and here we're actually using a two suction technique to be able to do the disconnection and, uh, and resect some of the tissue, and that's the, the midbrain on the other side of the arachnoid, and we're able to see, um, cranial nerve 3 and the PCA. Uh, as well. So, then we follow basically, um, the hippocampectomy, uh, posteriorly, um, to the tail of the hippocampus and try to connect that with, uh, where we have, uh, done our callootomy and, and our splenectomy. Uh, that was putting the cotinoid into the atrium to try to slide into the temporal horn to help our bearings. You can see that's, that's our disconnection, that's our faults, and, um, this is confirming our, uh, all of our disconnections, and that's the tent right there, um, where it's, um, white, and then that's our frontal basal disconnection, where we've, uh, basically followed the ACAICA. Um, and then, uh, able to connect that with our hippocampectomy. So we have our post-op imaging and our DTI to, uh, to take a look as well. Um, and I think really, um, having the intraoperative navigation with the landmarks, uh, was very helpful, but I also think that knowing the anatomy and knowing what to expect and, and what things are gonna look like, even if the navigation fails, uh, is very important. Um, but knowing that I can reach things safely and I can actually put the instruments that I need in to be able to control for hemostasis and to be able to do the disconnections as well. So, I think there are um definitely opportunities to expand uh endoscopic applications for epilepsy surgery. Uh, our, uh, preliminary results show that we can do safe application. We have a small case series so far, but, uh, I've been really impressed with, um, how the, the children Actually been able to um kind of mobilize, uh, a lot quicker. There's a lot less soft tissue edema, uh, and their recovery is, is faster. Um, and, uh, and I, I was actually quite, uh, pleasantly surprised that, uh, our anesthesia colleagues really did not see the need to transfuse any blood, um, and that our blood. Loss was actually um, much less than our, um, open craniotomies for hemispherectomies. And uh we've had comparable seizure outcomes, um, so far, but we need long-term follow-up and we need, uh, more patients. Um, and also our operative time has been, uh, comparable to the open ones so far. So, um, in terms of our case selection, um, I think we can expand, um, uh, our Uh, the types of cases, um, vary gradually, uh, but we definitely need multi-center experience and, uh, collaboration. So, I'm very excited to, to share the story with you, um, and, uh, I, I hope, um, Uh, you'll contact me if you're interested. Thank you. Thank you, Sandy. It's uh no doubt a tour de force and a, uh, uh, paving a new path that we all look forward to the future of this. It's, uh, it's tremendous application and, uh, what I, what I wanna comment on is the, the fact that you jumped into it. It seems like in a very intense way, the pre-clinical validation through, uh, a lot of work in the cadaveric lab and, uh, for, for innovative procedures like this, uh, as well as more simplified procedures. It, it really Harkens back to an early tenant that we all talked about, and that is the experience with uh both the equipment available as well as the familiarity of anatomy. Um, credit you for, for again taking this to a, a new level. We look forward to your future work. I think you've silenced our chat room. I don't see any questions coming in whatsoever. So, so, um, if, if there aren't any questions, do you have any further comments for Sandy? Uh, just very, very impressed. Thank you for joining us on that. Thank you. And I just want to congratulate you for being, uh, here present through the whole, uh. Or web seminar because uh you're a couple hours behind us and uh and, and, and I, I've watched you from the early morning. So thanks for being present to the whole, through the whole seminar thus far.