I've actually learned a lot from this. I'm also out of the Ojiman, Berger, Dufault school, and there's several things that, in terms of things I think I'll use to change my practice in terms of more monopolar stimulation. I'd like to know how I can get myself one of those brain misses for the OR too, because those are pretty cool. So, I'm gonna talk a little bit about how we do it. I just actually, Jim Rutkod just said we've probably talked a lot about stereo EEG, actually hasn't come up at all here, so I just put in a couple of slides too, because it's mostly a tumor crowd, to mention a little bit about stereo EEG and how it's gonna change some aspects of mapping. So, one of my colleagues, Mike Sisti, years and years ago coined the term that he always talks about, skull base versus skull top surgeons. So in fact, if you're a mapping surgeon, an epilepsy surgeon, a mapping tumor surgeon, you're a skull top surgeon, as opposed to a skull base surgeon. So, in skull top surgery per se, obviously temporal, extratemporal epilepsy, primary, I'm also gonna talk about secondary metastatic tumors, because I think they're a great way to use mapping, particularly in Rolandic regions, as well as to practice your skills when you're first starting to map, as well as approaches to cortical, subcortical, vascular lesions and other deep-seated lesions. And as multiple speakers have said, it's a pretty simple paradigm. We wanna maximally remove our tumor or our epileptic focus while minimizing the patient risk. And we're gonna hear this afternoon about all the ways that potentially we can map going forward. But I think right now, as Professor Dufault has shown us, awake mapping is necessary and sufficient for what you need in epilepsy or tumors to be able to remove what you need to, and to be able to overall affect the results you want. So as I said, I was fortunate enough to train in Seattle. Dr. Berger had just been there a couple of years when I got there as a resident. Hugh came when I was a resident. Dan Silbergel, who's still out there, has done a lot of mapping work over time. And of course, all of us started with Dr. Ojiman. So if you were out there at that time point, you kind of drank the mapping Kool-Aid. And it's one of those things where, over time, you realize that, in fact, that there's so many applications for this across the board, and it's amazing now to see a room like this full of people here all here for the same purpose. One aspect of it, though, as we see here, there's a lot of different ways to do this. And while I started with the same way that Dr. Ojiman and Dr. Berger taught me, how I do it now is very, very different in a lot of ways. And I'll try to go through some of those. So it sounds pretty simple, but there's a bunch of principles we have to think about. Obviously, as everybody says, you have to pick the right patients, the right pathology, as well as the patients in terms of being able to tolerate the OR environment. You have to spend a lot of time on their scans. As was talked about in the anatomy lecture yesterday, which was fantastic, what's the patient's sulcal anatomy? What's their actual gyrosulcal anatomy around the area you're going in? And as Hugh Dufault was saying, you should go in the OR with your three-dimensional map already there. Or as I say to our residents all the time, you should have the case dictated before you ever start. So what are you gonna see where? What are you avoiding? Where are the problem points? What do you wanna do in what order? And again, what's the patient's pathology, their anatomy? What's your surgical goal, and can you actually achieve it? And then, as people have said, what's the patient's educational background? What's their job, what's their interest? You actually have to meet your patient, get to know them, what's important to them. Are those things you want them doing in the operating room or need them to do? And then, you also have to know yourself. What's your experience? What's your case history on these kind of cases? So you're not gonna go in, and the first time you're doing mapping cases, you're not gonna start with a dominant temporal insular glioma, just like the first time you do a skull base tumor, you're not gonna start with a six-centimeter Petrus meninge. So know your learning curve, your experience, your results. Know your team. So do you have the neuroanesthesiology backup that you need? Is your neuropsychologist or neurophysiologist there? Are they gonna be there for every case that you need? If not, what's the backup plan? Who's your epilepsy monitoring person who's figuring out if you're doing ECOG while you're there? And I think most importantly is know when to stop, because you can always do more, right? But obviously, if you get into a situation and you're uncomfortable, then stop, because you can always come back, but you can't put the deficit back. And I think for all of us, I had seen hundreds of cases as a resident, but the first time you go yourself and you're in there and you're deep down and you're below the insula chasing a low-grade glioma and you're trying to figure out, is that low-grade glioma or actually is it striatum, because the striated tissue looks a little bit like low-grade glioma? If you're not certain, you can always go back. So, and again, know the goals of what you're doing. So on the left is a 1p19qIDH1 mutated oligodendroglioma. The goal of this surgery is complete total resection that's going to be achievable. On the right, in the middle, is a little bit of blood from an outside institution biopsy of a p53 infiltrating astrocytoma that's infiltrating right into the primary hand motor area with function completely infiltrated by tumor. So your goals of these surgeries are going to be very different. You're still going to go about them in similar fashion, but what you're going to achieve is going to be very different. And then again, the specific surgical issues that we've talked about here, I mean, it seems after two days here, you know, very commonplace, but at least in the United States, most neurosurgical residency in terms of neuroanatomy is cortically based. So we learn about cortex. We learn what gyrus is here, what sulcus is here. Hugh's up here showing a video saying, well, of course, this is where the IFOF is, and there's SLF3. You know, I mean, in general, that's not something that we're all integrating. I don't know about everybody in the room, but, you know, our residents are not walking up to scans necessarily the way they should be thinking, where's the white matter pathway relevant to where we're going to be on the deep side, which is the most dangerous part of the surgery. Sorry. So just my quick slide on advanced imaging, we've talked a lot about it. You know, I think we have amazing amounts we can get through it. One of the issues that many people have focused on is that it's very helpful, but it's not enough. The other issue, which a couple of people have talked about in the breaks here, you have patients who come to you who actually they come in because, particularly in a place like New York, everybody doctor shops, and they say, well, aren't you going to have a functional MRI? Aren't you going to have DTI? You can't, because they've been told that's the way to protect their function, that functional imaging is actually the key. And so you have sometimes patients you say, okay, well, you know what? It's a useful tool, and this is why it's really useful, but they're already coming in kind of brainwashed saying, well, you know, I need every one of these advanced modalities. And so a lot of times in those situations, it's the right thing to do just because of the fact for patient satisfaction also. So this was an interesting case just from a couple of years that really taught me something when you think you know most of what there is to learn about what happens in the OR. This was actually a bilingual lawyer who came in with this low-grade glioma. And what you see here, these are anatomically aligned images, is that on the brain image on the right, there's that little lip of cortex that was overlying the tumor. And the tumor was almost like an iceberg, almost nothing at the surface. So when we stimulated that lip of cortex with him awake, we got absolutely nothing. And we took out everything that appeared to be the gross tumor, and I was trying to think, should we push the resection further like Hugh's been proposing in terms of supratotal resections, and still awake, kept him awake the whole time. And at the end, once the tumor was out, both languages right in that lip of cortex. I've seen it twice now. I've never seen it before, but two times now I've seen that. So negative at the start, wide awake, functional after the tumor came out. So almost like a functional undercutting by the tumor at the start. So acute plasticity in an OR setting. So in terms of the preoperative anatomical imaging, as I said, really studying the vascularity, planning your approach. Dr. Berger talked a lot about preserving veins, which I think is critical on all of these surgeries. What are your at-risk arteries at the depths of what you're gonna be doing? What's the sulcal anatomy? And as I said, finish the case in your mind mentally before you ever start. And then for, as I mentioned before, for a motor strip met. So again, I think these are great cases for mapping because of the fact that most of the time they're subcortical. There's usually a lipofunctioning cortex in the primary motor area right over it. And it's a great case to get your team going on to work with. And you'd say, well, why not just gamma knife these? And I'll get back to that a little bit at the end. And then again, as Rich Byrne showed yesterday, what do you do for a glioma patient where they can't be mapped? And what's the best approach on that? And there's a lot of ways we can talk about that. And I'm gonna show one case at the end. So our patient positioning is pretty similar to a lot of the other groups. I prefer to position people supine if I'm working in the paramedian region. So basically hand motor medial, I'll keep somebody straight supine. And for language and hand plus face motor, then lateral position, straight lateral. We use Mayfield pins for everybody. Again, maximizing patient comfort, letting the patients help position themselves, and then really sedate them at that point for pinning is what we like to do in general. Being very careful about airway CO2. Again, most of the time when the patients are comfortable, particularly when they're in the supine position, they're gonna be sitting up a little bit. A precordial Doppler can be helpful because you can find a little bit of air before they wake up and start coughing. So again, this is just a standard OR positioning. We use a Mayo stand over the head. It's really simple. It keeps the drapes off their face, gives the anesthesiologist a great corridor. So you're frameless stereotaxy on the opposite side from a Mayo stand. There's a precordial Doppler in place here. We tend to try to use whenever possible the minimum amount of exposure that we need. We'll map beyond the margins with strip electrodes a lot, do a five millimeter or six millimeter hair shave just to keep the hair out of the wound even though there's no need from infection purposes. And again, as other people have said, set up for EMG for continuous recording or while you're stimulating. So here's what it looks like draped from above the patient's head. And again, with a Mayo stand there, the anesthesiologist can stand up. They've got a nice tall corridor to talk to the patient. If the patient's lateral, they can see their screen the whole time for all of their testing. And then again, relatively small exposures. So this is a primary hand sensory region glioma exposure. And you can see here, we've got basically a three by two and a half centimeter exposure. And once the tumor's removed, that's the primary motor strip that's actually above the primary hand sensory area where the tumor was removed. And so we like to do small exposures. We don't use ECOG arrays anymore. We use a single strip electrode, one four contact strip that we move around as we stimulate for after discharges point by point. We use that same strip for SSEPs. We use that same strip for motor stimulation, for continuous SSEPs if we need it, just one strip. I don't use any numbers anymore, any little white pledges in the OR because in a limited exposure, you're gonna have a limited number of places where you're actually needing to mark. So you mark them, you photograph them, and then you remember them. And then that way, we're not using any other equipment besides one four contact strip or a small grid if we need it. So again, limited scalp and cranial openings if possible. Again, Professor Schramm taught me a decade ago how to disconnect a hemisphere through a finger long incision for a complete hemispherectomy. So if you can disconnect a hemisphere through a finger long incision, you can resect almost anything else through a quite small incision and limited exposure. In terms of the Ogiman Stimulator, as I said, we use a strip electrode as a workhorse for SSEPs, motor stimulation beyond the craniotomy. Mitch taught me as a resident to stimulate leg motor through a strip electrode interhemispherically, and that works great. You can also use it if you're just working in the SMA region to do your motor stimulation just behind that. Again, continuous motor stim or SSEPs during resection. And one of the things too, if you're operating particularly in the SMA region, at the end of surgery, just very simply, just always confirm if your primary motor stimulation's working. Because if it's working, you can tell the patients with 100% certainty that they're gonna get better, that it's an SMA problem. And then when you go by the next day and they're mute and they're not moving at all, you're not left saying to them, well, I don't know how long. Because if the motor system's working at the end of your resection, it's going to recover. But if you don't test it at the end and you could have possibly undercut it, it's gonna be hard to know what to tell them. So again, we do use after discharges for negative mapping, use cold saline as I was taught by Mitch as a resident. And also, I find that a lot of times with grid mapping, because you've got one centimeter distances in standard grids, that sometimes you get unusual results that just don't make sense with grid mapping. You'll get a much larger area of positive stimulation in an epilepsy patient than makes sense. Those patients, when you bring them back to the OR, I find you have much more accuracy with the patient awake, stimulating their brain than you do through a grid if you're uncertain about it. So if we get anything unusual on our grid mapping, we'll just bring them back when we remove the grid and do the resection with them awake. So in terms of awake testing, we've had lots of talking about that. So the main thing too, again, is just modifying your tasks. In New York, we have a ton of multilingual patients. Sometimes we have dialects that we can't find translators for. We bring family members or friends in the OR. We test them ahead of time. We have them train with the patient, and then we have them come in the OR and actually help test the patient if there's a dialect that we can't find an interpreter for. And again, we use visual naming, reading, but we also use auditory naming, which I'll touch on very briefly. So again, here's a small subcortical cavernous malformation. This is actually a left-handed person. This is the dominant hemisphere. As a lot of patients in New York are, this is a polyglot, multiple languages. And so again, a very small exposure, SSEPs through a strip electrode. You can see the hemocyter, which is right on top of the dominant face area. So again, just finding a safe access point to go and remove a small cavernous malformation. Great case for simple mapping. So again, studying the anatomy of an individual patient, their lesion, knowing that on some below-grade gliomas in particular, diffusely infiltrating ones, you're gonna have function within the tumor. Again, we do use frameless stereotaxy. We use adjunct imaging, but honestly, we can't always get it to the degree that we want. I'm not fortunate enough to have the backup radiologic team that Dr. Berger has. Again, your sulcal anatomy, particularly if there's a sulcus at the boundary of where you're going in an epilepsy resection or a tumor resection, you can push that resection all the time, right to that sulcus, even if it's a half a millimeter away from a site. Interoperative awake testing of function. Rich Byrne mentioned this a little bit. I don't think there's anything better than having an awake functioning patient, particularly people are talking about awake or asleep. For me, if it's hand motor, there's nothing better for me than having a patient awake carrying out a task where I don't have to keep stimulating at any point, even with direct cortical stimulation. If you have a patient sitting there, you're in or near the hand motor area, and they're sitting there and they're tapping their fingers every 30 seconds for the anesthesiologist and the physiologist, you know the hand's fine. Same thing speech-wise. Once we do all of our baseline testing, our neuropsychologist just sits there and carries on a conversation. Where'd you grow up? What kind of work do you do? What sports do your kids play? These people are now carrying out spontaneous answers to normal speech questions and functions. You can't get a better language test than that in terms of testing somebody's function. So we prefer to have people awake during that critical part and actually just continuously test them. And again, the sub-peel technique that Professor Dufault showed us, really an epilepsy surgery technique being applied more and more over the last decade to brain tumors. And again, knowing your white matter boundaries and preserving all vasculature. So this is just a slide to remind me, particularly in the epilepsy world where you don't have a tumor. A lot of epilepsy resections, maybe there's subtle dysplasia, but the brain basically looks normal. So you gotta figure out where are you stopping. And as we learned with our anatomy lecture yesterday, that the posterior part of the superior frontal gyrus, it's contiguous, runs right back into the medial part of leg motor. So again, you have to be able to figure out there's not gonna be a sulcus there to stop you. So where do you have sulci? Where do you not? Where are your dangerous boundary points gonna be? Also in the epilepsy world, this is what a stereo EEG implant model looks like. So instead of opening up with a large craniotomy and putting on a big grid, stereo EEG is putting in as many as needed in terms of depth electrodes that are giving you a 3D representation of the brain through two millimeter screws in the skull. So instead of putting electrodes on the cortex two dimensionally, we're putting them all through the brain. Now, anyone here from Italy or France will kind of think, what have you Americans been doing for the last 30 years while we've been doing this? But it took us a while to catch up and realize this is a really valuable technique. But again, when you think about mapping this, it's totally different, right? You can't map a whole area of the temporal lobe to find a language area with stereo EEG. So you have to figure out from your electrodes, what can you and can you not? You can map white matter pathways that you can see exactly where they are. You can look at connectivity. You can look at cortical, cortical evoked potentials, but it's a whole new arena for studying the brain and learning how to map using these type of electrodes that we're all just figuring out. And then afterwards, this is actually a posterior dominant temporal lobe following a stereo EEG implant. And again, just ending up, you're doing a similar sorts of resections, but a much, much smaller approach. So we did a stereo EEG implant, found the epileptogenic zone right at the posterior sylvian fissure area, and we're able to remove this whole area. It's, this was actually a case of periventricular heterotopia, where in fact the epileptogenic focus was over top of the periventricular heterotopia, but not in it itself. So just in the last couple of minutes, so this is a map that Marla Hamburger, our physiologist, sorry, our neuropsychologist put together now over 10 years ago, almost 15 years ago, basically looking at the difference between auditory and visual naming. If you look at the red dots, those are all, the red and blue dots are all the visual naming sites, and the yellow dots are auditory naming sites. So basically answering a question in response to an auditory cue instead of a visual cue. And then you can break down differences between auditory comprehension and impaired retrieval, but basically what the arrows here show on the bottom is what happened to naming function when we removed auditory naming sites. So in fact, we test all of our dominant temporal lobe patients with visual and auditory naming, and spare auditory naming sites also. And then finally, just to touch a little bit on a couple of things, other examples so that people haven't touched on yet. So as I said, I think awake mapping for brain MET subcortically is a great place to practice your mapping, get it going. In our hands, when we do mapping-based resection, the patients do better in terms of function as well as seizure control than they do with radiosurgery to those primary targets. And in fact, this is one small series here of about 30 MET patients for Olandic MET patients, and we had 94% of them at six-month follow-up who were better and back to functionally normal. And so if you look at these two cases, these are two highly functional gentlemen, both about the same age in their 70s. The larger MET on the left elected to have surgery. Most of the time on these types of surgeries, a lot of times we're coming down through transcentral sulcus. The guy on the right really didn't want surgery. His wife had actually had a glioblastoma, unfortunately. Relatively small tumor, a bit of edema, a little bit of weakness, some seizures, and said he wanted GammaKnife. So the guy on the left actually already had a free flap over this for squamous cell cancer that we had to go through. And we went through about, if you can see there, there's a one-centimeter marker. So it's about a two-centimeter exposure at the back of the central sulcus. We found a safe window between aspects of hand motor, took out that MET, off steroids, actually still alive two years later doing fine. Again, oftentimes going through the central sulcus is what's necessary for these, right down the central sulcus. We don't usually map the motor part of the central sulcus because we're avoiding that in other epilepsy cases. But I can tell you in tumor cases, we do find function down on the motor side of the central sulcus down in the depths. And you often have to work between individual fingers to get there. So contrary to some of what we heard yesterday, we definitely found function there. And we also, when the METs stretch out the motor strip, you can find individual digit representation there also. How about the other guy who got Gamma Knife? So three months out, you'd say home run. Looks great, hasn't had any seizures. But three months later now, he's got a little bit of radiation damage despite a pretty low dose. He had 18 grade very conformally. He actually, when he passed away, had a substantially hemiparetic arm with major seizure problems. And that's why we've mostly gone to trying to resect primary METs in the Rolandic area or language area rather than Gamma Knife. Because these are very seizure-prone areas and I think the patients do a lot better and they're great cases for awake mapping. And then finally, this is a case of a high grade glioma who was aphasic despite multiple days of steroids. And so we said we would just do a debulking approach first with fluorescein guidance. So then the question becomes, when you know you've left some gross tumor, but there's all this infiltrating disease beyond the margin, should you or should you not consider doing more in somebody who's now getting better language-wise? And I think that's certainly a point for debate. So I'll finish up with one last case. This is actually a physician from out of state who was visiting her physician brother, had a speech arrest seizure, came in aphasic. After a couple of days of steroids, got better. And so basically for this, we were just looking for what's a safe approach mapping-wise to get down to this tumor. Took out both of these tumors at the same time, just through an approach through the frontal operculum with her awake and following her, mapping her function. And actually this turned out there was multiple other lesions in the brain. And through a combination of therapy over time, just got her six-year Christmas card last year. And I don't think we would have been happy going after that tumor without her awake. So again, just a few touched points. When you go ninth in a how I do it, most of the things have already been said. I would like to actually give my acknowledgments to the same people here. George Ogerman was a large part of the reason that I went to the University of Washington to train. Dr. Berger taught me so much of what I know about epilepsy and I've continued to learn from he and Hugh Dufault over the last 15 years. And the rest of the people are our team at Columbia because you need a team and it's never an I, it's always a we on this. So thank you very much. Thank you.

awake mapping

surgical procedures

epilepsy resections

tumor resections

brain mapping

patient outcomes