Good morning. I tried to put my talk together really from a practical standpoint and particularly for those of you who are interested in starting your own mapping program. What might you need for that? What are the basics? I'll say another few things that I think are unique to our center and then we'll do some cases. So first, these are my disclosures mostly related to intellectual property with cortical mapping. Awake surgery and mapping are really not new. This is the protocol that Adrian Verbruggen used at our center in the 1930s and you can see they're using awake surgery morphine and scopolamine back in the day when they were measured in grains and not grams. Epilepsy surgery has a long history in Chicago. This is the 1940s. Percival Bailey working with Fred and Edna Gibbs in the back over here and this is the team that taught Walt Whistler, that taught me a lot of the mapping that I do. And then I also spent some time with Dr. Ogiman and Dr. Olivier. So what I do is really a mixture of all of the things that I've learned. Most of it comes from the epilepsy side. So I've done a lot of epilepsy surgery. My practice is entirely brain tumor surgery and epilepsy surgery and I have a bit of a bias about electrocorticography which we're happy to discuss. But in reality, the majority of my cases are brain tumors and it's obvious to me the value that mapping brings to brain tumor surgery. We put all this together in our own cortical stimulation mapping protocol. I think that, you know, if you're going to be doing this at your center, I strongly recommend that you start by putting together your own protocol and you share it with your partners, share it with, you know, the nurses and the techs. Everybody in the operating room should know how you do what you do. I'm one of three people at our center that does epilepsy map or I'm sorry, mapping surgery. Dr. Munoz here does at least as much as I do. Dr. Sani who I think is here this morning as well. So I put all this together just so that we're all speaking the same language, doing the same setup and that you go to the operating room, you know, all of this will be there when you show up. So when do we do mapping? You know, this is just my opinion. Cortical mapping is appropriate in cases where focal appearing gliomas or epileptic foci or overlapping speech motor sensory cortex or their subcortical tracts where maximal resection may reduce symptoms, either mass effect or seizure or confer a survival benefit. So when don't I do mapping? This is again my opinion. Not everyone will share this opinion. I don't personally do mapping when there's a well-defined lesion with well-defined boundaries where a partial resection doesn't make any sense. So this is a dominant insular cavernous malformation. This to me is not a mapping case. It doesn't make any sense to leave any behind. The boundaries are very obvious. It's a straightforward lesionectomy with low permanent morbidity from this sort of an operation. So when do we do it? I think the perfect indication for mapping is a low grade glioma adjacent to eloquent cortex. So if you just take a look at this, it's just an algorithm we put together. Here's the surgery side and our decision for surgery. And if you go to the motor here, we'll do a decision about awake or asleep. I usually do them awake, but not always. And then if there's, if we do the mapping and there's no new deficit, we take it to gross total resection. If there's a new deficit, we stop. So I typically stop when we see about a three or four out of five strength. As soon as we see that starting to drop off, that's when we know we've done as much as we can. On the speech side, same thing, all of them done awake. If there's no new deficit, we take it to gross total resection, new deficit. And I'm fairly liberal in what I consider to be a deficit. If they start to hesitate getting their words out, if there's any perseveration, any of that, we stop. We know we've gotten as much done as we can. If you stop at that point within six weeks, almost all of them are going to come back to normal unless there's a vascular injury. In my opinion, these are the relative contraindications for awake craniotomy. We're, you know, we'll usually do an obese person, even if there's some airway concerns, we'll usually get those done with good extension of the neck and good anesthesia, we can usually get them through. I haven't done anyone less than the age of 10, but obviously the patient has to be cooperative. Mary Stratus went through a lot of this yesterday. We usually do functional imaging ahead of time, and we do pretty extensive preoperative counseling. The patient has to, number one, agree, consent, understand, know what they're going to be doing, and then we practice with them so that there's no surprises. These intraoperative troubleshooting we'll talk about a little bit later, but it's really coughing, apnea, and seizures that can give us trouble. So here's the logistics of cortical mapping at our center. So we have a mapping team, as the other presenters have. We have three neuroanesthesiologists who feel comfortable with the technique. We have seven epileptologists at our center, so there's always somebody available who can come up for the EEG monitoring, and then a neuropsych team, some of whom are here today. We do bipolar stimulating. We use map tags and, of course, the EEG leads. Our map tags have evolved over time. The first 40 or 50 years of mapping at Rush were done with paper mapping tags like you saw with the others, and then Lorenzo's laughing right now because we went through this thing where it went to plastic, and then those were outlawed, and the whole thing, you can't have something that might possibly be left behind in the brain. We never, half a century, never had a problem with this. Now they're all outlawed, and now we've had to create our own map tags with strings attached, attached to a unifying member so nothing can be lost. We have to recreate this every day. If this hasn't happened at your center yet, don't be surprised if it comes. Your safety team may bring this your way. So cortical stimulation mapping, the motor mapping, we can do awake or asleep. If they're asleep, you have to remember that you have to use a rapidly reversible paralytic. If you have four twitches, that doesn't mean that you're reversed. 50% of the motor in-plate may still be blocked with four twitches. For that reason, we'll sometimes combine it with EMG, as Mitch and others have described here today. Speech mapping has to be done awake. Standard naming protocols, that's what we do. Naming, we'll sometimes do repeating, counting, but primarily we're just doing the naming. We want the preoperative language accuracy to be at least 80%. If you give these people some pain medicine, maybe a little propofol, don't be surprised if they cannot cooperate with your language mapping. Everything has to be reproducible. Two out of three views, normal, standard Boston naming cards. So Mary went through this yesterday. We do the asleep, awake, asleep technique. I think you can get away, at least in our experience, you can get away without sedation if you're doing a convexity tumor. If you're in the middle fossa, though, the middle fossa is very pain sensitive. The temporalis muscle is pain sensitive. The middle meningeal area of the dura, very pain sensitive. It's hard for us to get patients through that without some, you know, deep sedation for the craniotomy. We always cooperate with the anesthesiologist to give them the best airway possible. We always pin the head. We do our craniotomy under deep sedation. We turn off the sedation during the craniotomy. We'll inject the middle meningeal artery as shown earlier. We ask them to hyperventilate prior to the opening. The only exception is if we plan a pre-mapping decompression, we'll occasionally do this. If there's an area of the tumor that is clearly away from eloquent cortex that comes to the surface and it's a very large tumor, sometimes I'll just open the dura, use our suction device, decompress the tumor until the brain is pulsating, and then open the rest of the dura. It does, I think, add a little bit of safety, and I'll show you a case later where you'll see what can happen if you don't decompress ahead of time. We always check patient comfort, go through the patient instructions again, EEG grids, and then I check the stimulator function. You're all familiar with this stimulator. We've, a couple of different people have gone through it. You have to remember that this stimulator is designed for obsolescence. It's supposed to be thrown out after five uses, and I've had cases where it didn't work after two or three uses. We have three boxes, and usually three of these available, and there are times we have to go through them because you'll find out sometimes this is no longer working and you really have to have a backup. I'll start off to make sure that the stimulator is working by stimulating the temporalis muscle, if it's available, at eight milliamps. If it moves, it works. We'll also check the digital display. There's a sound that comes with it, and when we're doing EEG, you should see the artifact on the EEG. If you don't see artifacts, something is not right. Three-second train, 60 hertz, one millisecond pulses. These are all very standard, except for when we're doing grids. I'll show you that later. I'll start off at one milliamp. We'll go up to eight. Remember, that's from baseline to peak. This is not peak to peak. Peak to peak is double that. I'm talking about the settings on the stimulator box when I'm talking one to eight. We'll increase the stimulation by one milliamp at a time until we see either after discharge or a behavioral change. I like to start with sensory, then go to motor, and then go to speech. It's just patients tend to tolerate the sensory a little bit better. That gets them used to the idea. That is, if all those are available for stimulation at the same time. We'll stimulate and move so we avoid summation and after discharge. This is what the stimulation looks like on EEG. If you don't see this and you're running EEG, then something is not right. Something's not hooked up. This is what an after discharge looks like. You can see it's a regional effect. It's not a focal effect. It's not happening between your bipolar stimulator. This is a remote effect, so that region of the brain is now having a focal seizure. That will go away over time. You can use cold saline or not. It'll eventually go away. It can generalize, so that's why we look for after discharge. I'm learning something today that you can get away with that without having to look for after discharge, but that's what we've always done. Our cortical stimulation parameters, we tried to make heads or tails about where we expect to see a physiologic response, where do we expect to see after discharge. I can tell you in hundreds of cases, it's been really hard to parse this out. This is a mapping case here, about 30 stimulation sites. Stimulated, you can see here, we went up to 14.5 milliamps. This is at .3 milliseconds, so you can divide by three essentially to the other parameters. With no physiologic outcome and no after discharge, here we went to 3.5 and got an after discharge in adjacent cortex. It's difficult to say exactly what is going to give you what at what stimulation level. We tried to make sense of it. This is a series of about 90 patients, consecutive patients that we looked at. This is motor response in green. Sensory response, I'm sorry, this is after discharge motor and sensory response here. We could not figure out and we could not predict when patients would get a response based on their demographics, based on their pathology. All we could tell was that if you're going to use general anesthesia, you need to start at higher levels and you'll need to go to higher levels with your stimulation. This is our setup in the operating room. This is a left-sided craniotomy. Here's the surgical team. This is the neuropsychology team over here with the neuroanesthesiologist. On the other side to my left are going to be the neurologist, neurophysiologist. Here's the EEG monitor there. This is just a standard stimulation case here. There's a certain rhythm to it in the room. You can listen to it. What you're going to see here is we'll get speech arrest right there. You'll be hearing the neuropsychology team speaking. Then you'll hear the response from... So this is the flow. This is what you should be expecting to hear. So the neuropsychology team says, what is this? There's a three-second stimulation by the surgeon. The patient then says, this is A, and then names the object. Then over to my left, I'll hear from the epileptologist, AD or no AD. The neuropsychologist will note whether there's a speech alteration or not. The surgeon tags. We move on. Doing it this way with that sort of a rhythm, it can be actually quite quick. I saw some of the... When we did the survey to find out how long does it take to do speech mapping, there were quite a few people that were saying over 30 minutes. It really should not have to take that long. Once you get used to this, you can really get the speed down. Here's an example of a speech mapping case. This is a 62-year-old right-handed woman who had had progressive left temporal glioma and seizures. She'd had a subtotal resection 12 years earlier. Chemotherapy, radiation therapy, medically intractable epilepsy, growing glioma, some speech problems, and memory problems. So the question for us was, can we remove the rest of this and the part that gets up to the portion of the inferior parietal lobule without hurting her? fMRI was sort of sparsely positive through this area. So we decided to do this awake with mapping. Here's the mapping right here. Bottom line is the entire temporal lobe was negative to 8 milliamps. So I proceeded with the resection. And we ended up with a complete surgical absence of the dominant temporal lobe back 9 centimeters. No speech deficit. One point I want to make though is I'm removing all of this. I'm not going into this deep parasylvian fMRI area. I'm not mapping that. I don't know for sure if that's critical or not. But you can do very large resections in the dominant temporal lobe. Some of this might be plasticity. Some of it might be that she just doesn't have a temporal speech area. Whatever it is, we can get very large resections safely if we do the mapping. Here's another example of that. This is a very large glioma. Left side, frontal lobe, temporal lobe, parietal lobe, sylvian fissure right here. fMRI sparsely positive. We've done the mapping here. Here's our map tags. Motor, sensory, two separate speech areas, inferior parietal lobule. Here's the sylvian fissure which Mitch pointed out. We'll bolster that with gel foam at the end. Another 9 centimeter dominant temporal lobe resection without a new speech deficit. Now this person came to us with difficulty with reading. She left us with difficulty with reading, but no fluency or naming problems in her speech. So you can see we've resected a good portion of that fMRI speech area, but not the deep parasylvia, not the stuff in the inferior parietal lobule. Motor mapping example. I think Mary showed some of this yesterday. Here we have the motor movement here and then just discussing what we've done here. We found motor hand. All of this was negative day after discharge. With the resection, I always start away from the most critical functional area and then work my way towards it. If I have a choice, I'll work towards motor first and then towards speech. Motor mapping, similar flow, stimulation, movement or no movement from anesthesia, and the physiologist and then the neurologist says after discharge, no after discharge. Here's a case where we decided to use general anesthesia, 29 year old headaches, confusion, and seizure. Very large glioma, somewhat remote from what should be speech cortex out laterally. She was a little confused. We had too much mass effect. I decided to do this under general anesthesia and just map motor. You can see a significant mass effect here. Here's the resection looking into the ventricle and an intact patient. You can see we can take this exactly to the precentral sulcus now because we know precisely where the motor area is. When you do these larger sections, you really have to watch out for these veins that are sagging. You have to fill that cavity with saline, otherwise that vein will pull free. Motor and speech mapping, same thing. We use a lot of ultrasound. We find the precentral gyrus here. We find inferior to this. We find speech function. Very large glioma, a lot of mass effect. If I had to do this over again, I would probably have resected first because if this person gets a seizure, that would come up aggressively. I'll start the resection again remote from the area of function. I'll work towards motor and then towards speech. Here's our resection with the operculum spared. The patient had a slight amount of speech difficulty towards the end, which caused me to stop. There's our resection. Again, mass effect. Now, this is what can happen if somebody coughs. You've got a large tumor and somebody coughs and bucks when they wake up. This person had some problems with asthma and some sleep apnea. When he woke up, I'd opened his dura, started coughing. You can see the subarachnoid hemorrhage that can come up. You have to be careful of this. That's why, in my opinion, it makes some sense to do some decompression remote from functional areas before you open the dura in some cases. Subcortical stimulation, I use a lot in the insula. You can get a nice resection with this, finding the insula, the internal capsule before you go through it with good, durable results. This is just my personal experience in the last few years. This is just cases that involved speech and sensorimotor. We're getting very good resections here. No more mortality. I had two perforator injuries. These are enormous tumors with two perforator injuries and moderate hemiparesis as a result. Mapping does not protect vascular structures. That's an important take-home message. When I can't do it, I'll do subdurals and depth electrodes. Here's our series of about 150 of these that we just published. I do combined depth electrodes with grids. We do this slightly different. We use a GRASS unit, two-second trains, 50 hertz, 0.3 millisecond pulses. This is the way we've done it at Rush for 30-some years. We've never changed the parameters. It's interesting how the mapping goes when you're using 0.3 milliseconds. But we can get really, really nice mapping done with the subdural grids. As Dr. Schramm pointed out, this is done luxuriously over a couple of hours, and we can get some very nice mapping. We combine that now with gamma frequency mapping just to learn the technique. I really think the gamma frequency has a future in mapping. I just want to thank the Rush neuro-oncology team and our mapping team, and thank you for your attention.

awake surgery

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