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Atlas Innovations: Stealth Autoguide™: Initial Clinical Experience | 1-Year Update

David Adelson, Vivek Mehta, and Manish Shah

March 29, 2021

Transcript

- Hello, ladies and gentlemen, and thank you for joining us for another session of the webinars series from the Neurosurgical Atlas. Our lecture today is a special one. It's the Atlas innovation series, which we'll discuss new technologies which have made a positive impact on patient care. Today, we'll be talking about the Autoguide. It is a cranial robotic guidance platform that can make the work of the surgeon in terms of stereotactic significantly better. We have three speakers; Dr. Dave Adelson from Phoenix Children and Barrow Neurological Institute, Dr. Vik Mehta from Hoag Hospital, as well as Dr. Manish Shah from UT Houston. Dr. Mehta will be talking about his experience for the past year using this technology. And we appreciate his time for doing that. And in the middle of his lecture and at the end, we'll be further discussing these techniques and the use of this device by Dr. Adelson and Dr. Shah. And Vik, we really appreciate your time. Dave and Manish, thank you for being with us today. And Vik, please go ahead.

- Well, thanks Adam. Good morning everyone. And thanks to Dr. Shah and Dr. Adelson for joining us. I'm happy to talk about our initial experience with the Autoguide robotic planning system. We've had this onsite for about one year and have developed an early clinical experience that we'll be discussing. My disclaimers here and disclaimers from Medtronic. So here's the outline for my talk. I'm gonna review cranial robotics and neurosurgery in general. This is an area where I think we need to talk a little bit more about what's the hype versus the reality, and then have a discussion about what's driving the trend towards robotics. I'll then introduce the features of the robot and our decision-making process and how we analyze the features of the competitive systems and made our decision. We'll review our case experience, show some videos, summarize our data, and then share some files along the way and have some questions at the end. So robotics in neurosurgery, it seems like every year on the cranial or spine side, there's some new robotic platform, very highly publicized and people get really excited about us. And we took a step back and asked, is this a hype or is this really something we wanted to look into? No doubt, robots are becoming more popular in epilepsy surgery, particularly, as we see the shift towards SEEG over strips and grids. But really, generally in medicine and manufacturing, the automation of tasks is leading to improved efficiency and reduction of error. And again, in neurosurgery we're seeing paradigm shifts that drive towards robotics. With laser ablation having an expanding role in medial temporal lobe epilepsy and hypothalamic hematomas, radiation necrosis, deep seated tumors, cavernous malformations, and recurrent tumors. And we see that adjuvant therapies are becoming more effective and precision medicine playing a larger role. And that usually involves getting tissue for analysis and sampling. The boundaries of resection, What boundaries are recurrent? From a patient perspective, I think patients are seeking out more minimally invasive options options that will have less pain, will help them get home faster. And as we know, we use epilepsy surgery as an example, we know how dramatically underutilized it is. And part of that may be that the approaches that we've certainly been using have not been patient friendly. There's also a driver on the surgeon side, we want technology to make our cases more efficient and safer. We want a versatile platform that integrates with our existing technology. And whether you're a fellowship trained stereotactic epilepsy or functional neurosurgeon, or a general neurosurgeon with a basic experience with navigation systems, we want something that's seamless and can work for all. Then at the end of the day, as we think about these approaches, really what we ask ourselves is, does it make surgery safer? Does it improve accuracy? Does it reduce the overall risk to the patient? And is it less invasive while still achieving high therapeutic and diagnostic effects? And so I think the answer to those questions are being clarified. This is a review paper by a group of epilepsy surgeons discussing the role of technology in their host of issues discussed including the integration of navigation platforms, collaborative planning, reducing overall time, costs, reducing surgeon, error, fatigue, and minimizing waste. And from this, I think we have really good data that robotic platforms leads to faster and more accurate placement of electrodes in biopsies. And the systematic review and meta analysis comparing robotic and frame based platforms does demonstrate reduced entry point error and target point error with these approaches. So here are the currently available cranial robots, all of which can very accurately place electrodes or perform a biopsy or a place a laser fiber. And so looking back, our motivation to look into the potential differences between the platforms, I really liked the slide by Dr. Wolfsberger where he discusses needs what needs are. We'd like something minimally invasive, highly efficient, able to handle an increasing number of targets in cases. And then based on those goals, he described what the requirements of a robotic system are. And he concluded that maybe we need innovation in this area. So if we compare across the systems and we want to look at what differentiates them, we can easily see that the weight and size of one is clearly different from the other. Its happily named a miniature robot, it's just under two kilograms and an overall dimension of about 10 to 15 times smaller than the others. But size and weight is important, but that was not our primary factor. We really wanted to see data regarding performance. We were glad to see there several published studies from Dr. Wolfsberger's group. So first looking at accuracy, set up time, initial positioning and learning curve, we saw good data published in JNS that the Autoguide performed well with errors at entry of about 1.3 millimeters and a target of less than one millimeter. So, this definitely caught our attention. Particularly interesting, I was looking at implantation of depth electrodes systems. This is a large part of our practice. And you see from their published study here, that the robot was highly accurate and efficient. And a summary from this paper showing a depth electrode placement, real entry-- I'm sorry, real error entry and a target of 1.3 millimeters and 1.76 millimeters, which for SEEG would be accurate. And then finally looking at biopsy, similarly, very good published data regarding accuracy reduced overall time and minimizing the size of the skin and incisions. So, our decision making process as we began to look at the various systems, we wanted something that integrated seamlessly with our existing navigation platform. And whether one of our DBS surgeons or skull-based surgeons, the epilepsy team, or oncology surgeons, let their needs where we wanted them to feel comfortable with the system. We wanted a robot which was versatile that would be able to place an SEEG electrode just as easily as a laser ablation fiber or a biopsy needle. And because each of us have different focuses, we wanted everyone to be comfortable. Workflow and efficiency was important, but safety and accuracy was paramount. And as we made a business case to the hospital, we started thinking about the economics and the lifespan of these systems. We wanted something that would last but not so expensive, that it would be hard to justify making an upgrade once new versions were available. And now making a case for costs per case or cost per lifetime of the robot and the Autoguide system made sense both to us and to our administrators. So here's our case summary experience. We've done total of 15 patients with SEEG both unilateral and bilateral 13 biopsies, six laser ablations, and one RNS placement. You can see our average registration error for SEEG is 1.2 millimeters. Accuracy on target alignment ranges anywhere from 0.0 to 0.3 millimeters. Average electrode accuracy 0.29 millimeters and our placement time is right under five minutes ranging or trending down. When we started it was taking much longer, but as we optimized our work flows, we're getting much faster. We've done both unilateral and bilateral and placed total of 125 electrodes. biopsy results look similar and registration error was about 1.4 millimeters, still a very good target align-- Accuracy on target alignment. I had diagnostic tissue in all cases, no need for repeat passes or take back for a repeat biopsy. Very fast, 5.5 minutes for the average biopsy time once we perform your timeout and we've performed a posterior fossa biopsy as well. Laser ablation cases, we've done a total of six, four for epilepsy and two for oncology indications, a good registration error, good accuracy on alignment. Insertion times are ranging from six to eight minutes. And in all cases we've been able to place a fiber on target in the first pass. We haven't had to go back and replace the fiber, and we haven't had any symptomatic ICHs or any neurological deficits in these cases. So this is what the robot looks like, it's quite small. And next to the Stealth station. You can see it's housing this card, and you can see the relative size. The essential components of the system, or a rigid MAYFIELD or similar type skull adapter with a Starbust which allows attachment of the navigation arm, which will we're all familiar with, and attachment of the robot. This configuration does allow the robot in closest proximity to the patient, but you don't have to attach it this way. It does also have a bed attachment. The robot has its own tracking and continuous navigation feature, so, it doesn't depend on what position or what attachment you use, it can be accurate in either configuration. And hopefully you can see here that there are four possible areas where the robot can attach and be adjusted. If targets are further away, and you need a better reach, you can adjust this under the drapes and you can turn this clamp here under the drapes, which we've done if there are targets further away. Just another picture of how the system is set up, how it can attach to the MAYFIELD. So here is essentially our setup for SEEG. These are the essential components to place a depth electrode. You have your traditional navigation tracking arm. This is the drill which we'll get into a little bit in more detail. There's some features of the drill that are particularly helpful including a depth stop guide. This is a drill guide, this is a obturator, this is a SEEG reducing tube, your anchor bolt, a screwdriver, just a couple of pair of pickups, some local and your ruler. And that's really it, this is all we have on the side table when we're placing electrodes. So, as I mentioned, the drill has a depth stop guide. And when you plant your electrodes or your biopsy or your laser fiber, you can measure the thickness of the bone and you can set drill guide to avoid plunging. We found this helpful in terms of increasing the speed. There is feedback on the drill. So just like any other perforator or drill, you'll feel the inner middle and outer tables, but it's nice to have the guide knowing that it won't punch. This is the configuration in the O-arm, to give you the post-placement confirmation scan. This is what it looks like. And this is the kind of the workflow. And I think you can tailor this to your own needs and what you like. And Dr. Wolfsberger uses a certain set of... A certain workflow; localized entry point, where the pointer makes the skin incision there, then it positions the robot. It does the alignment, it does the drilling and then it does the final steps. I think Dr. Adelson first uses the robot instead of the pointer. He uses local, then drills and, and starts to biopsy needle or the SEEG electrode. I add one little different step, which minimizes the skin incision. So I will localize with the robot, I float the drill guide and I use the bovie to make a skin incision. And then I use a long cautery tip bovie to check for the drill opening in case there's any bleeding. And then I do the placement of the instrument. So this is... There's versatility, you can see what you like, you can borrow what you've used with a frame based approach or other approaches. There's a lot of versatility, there's no one way to do this, whatever you feel comfortable with. And we'll just look at a video of kind of the setup. So here's the robot to target and through the drill guide, I just use that long protected bovie tip and make my initial skin incision that way. This helps minimize bleeding, makes the incision as small as possible. And here is the drilling. So you've made your skin incision and you have your drill to the appropriate depth set. And the robot is targeted to the appropriate trajectory and you drill your initial hole. This is just a second view of the cautery through the skin. We can go to the next slide. And again, we talked about the drill depth stop, which we use. This is a view of the targeting of the robot in action. We can play this video. Oh, I'm sorry, this is the anchor bolt. So once you've drilled your initial hole, you back load the anchor bolt and screw in the anchor bolt. So basically three steps, skin incision with the bovie drill and load your anchor bolt. Next slide. This is a view of the anchor bolt being drilled in through the robot, so everyone can see.

- Well, Vik, that was great. I learned a couple of things there too myself, so I really appreciate you're giving this presentation and your experience today. I guess part of my question is, what did-- You kind of alluded to the learning curve a bit. And so, where did you find that you were able to kind of create new efficiencies from when you started to kind of, when you started really running through these things?

- I think I'm getting familiar with the system, getting hands-on understanding how the tracking with the robot works and how to set up your steps to minimize redundancy. I think having everything set up on your back table, having the whole team understand what the workflow and processes are, having all your equipment open and ready, having a backup target and entry point set up in case of a... For example, a biopsy, if you don't have diagnostic tissue, that helps. I think positioning of the patient and positioning of the robot are very important. You wanna test out prior to prepping and draping that the arm is going to reach your target and there's no collisions with the MAYFIELD. It's great to have an assistant who understands the remote for the robot. So your nurse practitioner or PA can control the robot while you're doing the work at the patient's head. So all these things they may cut down 15 or 20 seconds here, but when you put them all together, instead of 10 or 15 minutes, you're getting a biopsy or SEEG done in just a few minutes.

- Yeah, I liked your thought on making the incision with the bovie. I hadn't tried that. Part of our-- We do the same thing where we actually float the guide a little bit, just inject with local, make an incision and then use the bovie to make the incision. but yours looked like it might save some time going instead of the back and forth we do in order to sort of point at that particular entry site. One of the things that I didn't see come out on the video, and maybe you can allude to it, so after we drill the bone, I will probe with the bovie, with a K-wire and then use the bovie as a... To go through the dura. Do you puncture the dura with the biopsy needle? Or do you also do a coagulated entry through the dura?

- I will use the obturator, the feeler to see if oftentimes with the drill I've made an opening through the dura. Sometimes I have it. If I haven't, then I'll use the needle tip bovie to do that. But if I check with the operator and if I'm through, then I'll go ahead and go with the electrode and stylet or biopsy needle.

- Yeah, we have the same challenges. I think this is a wonderful drill just to maintain the accuracy and things like that. But one of the problems we was with the feel of going into and through the bone and then to avoid going through the dura. And so, do you-- What we did is we adjusted the RPM on it, so that we actually use it at a lower RPM, we used 15,000. For me, that gives me a little bit more feel for when cortex, cancellous and then inner cortex. And so we've avoided penetrating the dura in that way. What do you use with that?

- I initially started at 75,000, very fast. My rationale was with high-speed and initial low pressure, and I would sort of pulse the drill that I would minimize the air. What I found though, was that at that speed you have much less feedback, and there actually is a little bit more chatter or error at the when you're first starting to drill. So I've adjusted, I now do the drill at half speed. I don't pulse the drill, I keep it at a continuous pressure and continuous RPMs. I do go slower and that has improved accuracy. And I agree with you that it's much less likely to penetrate the dura in that way. So, the lower speed, continuous pressure technique has been my method now.

- Yeah, I would agree with you. I liked the lower speed for the tactile feel of the drill to be able to pass it without over-penetrating. I think that that's important. One of the other things that we had a challenge with and maybe you can address as well. When we were using the drill for the laser ablation, if you start the drill, like for example, if you pick your depth and you're still short and you now have to go and re-drill it, I think one of the important things is that the drill needs to be at speed before you enter the hole. Otherwise, it will create a wider opening. And so we were having anchor bolts that were not engaging well enough with the bone, because the hole, the chatter on the initial turning it on, tended to pull away more bone than the anchor bolt or for even the laser ablation or the SEEG electrode. Has that been at all your experiences? How do you use it?

- Yeah, I had one case with that exact experience. I drilled the pilot hole and because of the chatter, the opening in the bone was slightly wider than the diameter of the anchor bolt and the anchor bolt was slightly loose. So I did re-drill a hole, and that's what prompted me to go a little bit slower. I think the trajectory for the occipital approach, MTLE ablations, there is a potential for a lot of skive on the bone. And so just being very mindful of possible lateral deflection of the drill, which is one of the great features is that there's continuous navigation. So if you are deflecting laterally, you'll be able to see the error in real time. But also the trajectory through the bone is really at an angle. So you're not drilling perpendicular through the bone. So, having a feel and an appreciation for that angle and minimizing the widening of the hole is very important. But yes, I've had that same, same experience and I had to fix that.

- Are you using different anchor-- Are the anchor bolts that you use for your SEEG the same? Are the anchor bolts that you use for the same diameter as what you use for the SEEG? Or are you using a different diameter drill?

- For SEEG we're using the 2.4 millimeter drill and for the ablation or using the 3.2 millimeter. For biopsy, we are using... I started with the 2.4, but I've switched to the 3.2. The biopsy needle is a little snug with the 2.4. And since it's only one incision, I'm okay making the incision a little bit bigger to make sure that there's no collision with the needle as you enter the bone.

- Great. Did you ever quite-- I'm sorry.

- Yeah. How about integrating the O-arm for auto registration and let's say, or using the post placement exam and merging it with the pre-planning and sort of assessing the accuracy that way. Would you mind commenting on the use of the O-arm for workflow efficiency?

- Yeah, so I think there's... With the O-arm there's two components, either your registration component or your post-placement confirmation. And we've done both. I think if you're using bone fiducials with the O-arm, that's gonna give you a really high degree of registration accuracy. And post-placement, if you want to... Before, for example, if we're doing the laser ablation in case you wanna verify the placement of your laser fiber in the appropriate placement, that can be very useful. So we did that for several of our initial cases. It obviously does add time. After developing an experience and being happy with the results we've stopped doing that. We feel confident in the accuracy. What we routinely do for every case is after an SEEG placement, we get a CT scan and merge that with our plan and we'll look at our error. And you'll see that in the upcoming slides. Similarly with laser ablation, once we've done our post ablation scans, we'll do a full MRI and merge that back in with our plan and look at our error and see where we can correct. So there's a continuous process of quality improvement of identifying what are the factors in accuracy. I think one of the most important things is minimizing that registration error and making sure that that green cone of accuracy you get when you do your registration is less than one millimeter cone of accuracy encompasses the area that you are operating on. We get a stealth MRI and a stealth CT, which we merge. And then we do a registration based off of the stealth CT, which generally gives you a much lower registration error. So, we will tolerate an error in the range of about 1.3, 1.4, but you can usually drive that down even to less than one, which we attempt to do. If you're using bone fiducials or skin fiducials, I think that's gonna give you a much even better accuracy.

- Yeah, I would agree, I mean, I-- We only do MRT2 stealth initials scan. And I agree that the initial registration accuracy is important and then it's the inter-operative accuracy. I mean, again,, that becomes your total error. So if you're up above, you know, 1.3, 1.5, now you add on the extra 0.2, 0.3, now you may have potentially close to two millimeter error. And for some of the HH cases, especially the deep ones, that's where we felt like we weren't right on target. So, again, I think that I would agree that we usually shoot for hopefully, less than 1.0 on the registration. And then we will often during the actual drilling, if we felt like there was some drift or anything else, then we will just re-target and try again to make sure we can get us the accuracy as low as possible.

- Obviously, Dave, just like any other stereotactic system, the accuracy of Autoguide is dependent on the accuracy of the registration. Could you comment on your nuances of registration, Dave, particularly, please?

- Yeah, so we don't have O-arm at present. We just do our registration with surface registration. I agree with Vik, I don't do it until we get to 1.3 or better. Really, at least in the last couple of months that I can remember, all of ours have been under 1.0. Part of it is we do the surface registration, get as good a baseline as we can. And then we'll do point off of lateral canthus, nasion and other lateral canthus. And sort of then the calculated registration really gets us below 1.0. We haven't-- We've got a group here that helps us to get the registration and they do a great job that way.

- Got it. Before we even go to the cases, Dave and Vik, would you mind maybe discussing what are the pitfalls for someone who wants to use this system from the beginning? And sort of beginner, what are the pitfalls they should be watching for, please?

- Yeah, I'll start. I mean, I think that we're really looking at this from a number of angles and Vik covered a few of them being the size being one of our issues, the value, again, looking at accuracy and cost efficiency, having the smaller system was better for us in our workflow and our OR sizes and those kinds of things. The other issue for us was that it really was fairly seamless and we already had that image guidance system. And so, being an older person, I didn't really wanna learn too many new tricks. So, it was a little bit more integrated with kind of what we were using already. And so, learning new software was not as big an issue for this particular product.

- Vik, would you mind to comment on that please?

- Yeah. I did a dry run with the robot and I really liked the real time accuracy. I started with the right frontal brain biopsy, something that's very easy to convert to open if I had to, so I had a backup option and that sort of helped. So I did a couple of pretty straightforward cases, biopsy cases, a simple SEEG case. And then I ramped up the complexity as I learned the nuances, but also the team. And I think your team is gonna be really important for the accuracy and the efficiency. So I'll routinely have my nurse practitioner register the patient while I'm watching. And she's become very good at minimizing the error. And then on the scope tech side, making sure they're familiar with how the setup needs to be arranged to minimize any interference with the camera, the draping, all those things play a role. But I think in general, start with easy cases and then ramp up slowly, do a dry run, really understand the importance of the registration error, minimizing that. If you're most confident doing an O-arm spin with bone fiducials, then by all means do that.

- Yeah, I mean, I would agree. I think it's... The learning curve is actually fairly quick with it because of the efficiency of the system. I liked Vik's comments. The mayo stand should really have the minimal amount of equipment on it. It makes the SEEG go much quicker being able to kind of have your scrub just really, boom, boom, boom, and go through with it, it really does help with that efficiency.

- It makes good sense. Thank you, Dave, thank you, Vik. Maybe we can go ahead and do the cases and I'll let you guys discuss them and give us some of your, again, technical pearls for using this device sufficiently. Thank you.

- So example of some of the cases we've done, here's a deep seated mass. This ended up being a GBM that we did a biopsy on. Another case he was a really unusual enhancing lesion in the posterior fossa that we did a biopsy on. So it gives you an idea of the versatility or the range of the platform. So this is highlighting a little bit more on the registration sort of error and accuracy. You can see that we achieved a error of about 1.3 millimeters and that our green circle has expanded to the area where we're placing electrodes, and that really, this should be an accuracy of less than one millimeter. Here's one of our SEEG cases. You can see a unilateral case with some temporal, some frontal depth electrodes, kind of a variety of areas. So I think having the robot be able to reach all these is something that's important to check beforehand, you may require a change in the position of the arm under the drapes, which can easily be done. But this can tell you whether you're in the midline frontally or in the posterior temporal lobe, you can reach everything. Next slide. So, as I mentioned, we routinely do a post-op CT scan and overlay that with our plan. So you can see the yellow dot is our plan and we've got the electrode right under there, and you can see where its essentially dead on, up in the right-hand corner. And then we have trajectory views in the bottom two windows. And we can see it's as good as you can hope for. Dr. Adelson, any comments on this case? Did you place similar type of electrodes?

- Yeah, that it's an interesting case. And I guess I'm interested Vik, do you do the O-arm spin afterward to check all your accuracies on here for this? Let me ask you, and I mean, with regards to the SEEG electrodes, do you find that you have the better trajectories with the closer to the surface versus the deep? Sometimes we're challenged for some of these deep ones like the orbital frontals and/or the occipital where we're going a long distance or HH cases. I'm just interested in sort of how you gauge your accuracy. And do you do this type of post imaging about... On all the patients?

- We were in our initial, maybe five cases, we were doing O-arms spins, we're really happy with the accuracy. So now we've transitioned to a post-op CT scan once the patient's in the ICU and we secondarily bring the scan over. Where I find the most... Where I spend the most focus on ensuring the accuracy is really in the temporal areas. Because of, I think the greater thickness between the scalp and the bone through the temporalis muscle. Sometimes that muscle can be very bulky and you have several up to two centimeters of thickness between the surface of the skin and the bone. So if you're going to float the drill guide, you just have to be really conscious of that increased distance. I have resorted to making a slightly larger incision in those areas and anchoring the drill guide to the bone before drilling. It can, I think it does lead to better accuracy. It does increase the operative time slightly, but it's a trade-off that I'm willing to live with.

- Yeah, I agree with you. The temporalis is thick. The-- I would agree with you, I think that the bone anchor is useful. One of the ways that we... As I mentioned a little bit before, is when I use the obturator, I really try to push the obturator up against the bone. So either through the muscle or if we don't have, if we're in an area that doesn't have the temporalis and then try to really slide the bone anchor along that same trajectory, watching on the screen to see that it's not off plan. And I think that-- And if it does go off plan, then trying again. And again, just to try to keep the drift, excuse me, from occurring, so.

- Yeah, great points. I think all of those things, the-- I think once you've drilled your hole, that's really, you've committed your trajectory in that step. your anchor bolt, your electrode, they're gonna follow that initial opening through the bone. So maximizing the accuracy at the drill step is really important.

- Yeah, one other thing that we tend to do, I don't know what your thoughts are and I'm interested, is that I'll actually take the K-wire which we use the same for the laser, is that I'll actually go all the way to target with that, with the blunt end. And that way create the track for the electrode or the laser or the biopsy needle, so that it just sort of falls more within that. It just... To us, it helped with our accuracy.

- Yeah, I really liked that. I thought about that. For my RNS placement, I have done that since it's a more permanent electrode. I likely will incorporate that into my practice, I do like that. If you're-- Especially, if there's no way to avoid crossing a soft side and you feel like your plan is safe and you can get a little bit of deflection across the pia and arachnoid boundary. And it is nice to have a rigid track of something rigid having gone through and developed a mature track that you can then pass the electrode through. As you know, the electrode, even with the stylet in, does have a little bit of a wiggle at the tip, and you can get slight deflections, which usually are fine, I'll show a case of that, but I really like that idea.

- Yup, I agree. Okay.

- So we'll show this case, this was interesting. This was a SEEG case, which then required an open resection. And you can see here, this is a Sylvian fissure and this is a superior temporal gyrus. I love showing this to the neurologist. We had planned an electrode through the superior temporal gyrus, just inferior to the fissure by a couple of millimeters. And this is when we opened up after we removed the electrodes, this is what we found, really dead on. And I was impressed by how little surrounding brain injury there was. You can see the cortical vessels, you can-- Really, no traumatic subarachnoid hemorrhage or no injury adjacent to the fissure and the electrode. This is what I like to believe happens every time I place an SEEG electrode, is it goes in exactly at the right point without any injury to the surrounding brain. This is another SEEG case, this is unilateral. We can see registering off the CT scan, getting an error of 1.4. This was one of our earlier cases. We were driving down that registration accuracy even lower. You can see here a number of temporal electrodes some posterior electrodes, occipital electrodes as well. Go to the next slide. And this was one where we did do an O-arm merge. And so you can see we've got our plans here on the right. We've got our initial MRIs, which we plan off of. We've got a CT scan, now we've done an O-arm spin and we're merging that. And we got a really nice co-registration with the O-arm spin, even with the patient's head turned and potentially some artifacts from the MAYFIELD or from the anchor bolts. An O-arm scan does register or co-register really nicely with your preoperative plans. You can go to the next slide. Placement and confirmation. Again, just driving through one of the targets. Yellow dot is our plan and underneath you can see where the electrode is and you can see we're nicely dead-on. The trajectory views in the bottom window show that we're a perfect placement of the electrode. Next slide. Dr. Adelson, any comments on that case or utility you feel in O-arm registration?

- Yeah, we don't have an O-arm. I think that it makes sense. We do the same thing as you and that we get a CT scan afterward just to confirm that we haven't caused any bleeds and that our electrodes are in the locations that we tried to shoot for.

- Here's the case of a bilateral case. You can see a number of electrodes. And this highlights the versatility, I think of the robot. In this particular case, we did move the robot from one side of the bed, to the other, not as inconvenient as it sounds. It involves detaching it from one bedrail and putting it to the other. We can keep the patient draped in the same position. We don't need to turn the head. You do have to pin in a very effective way to ensure that you won't collide with the MAYFIELD, but it is possible. We have a number of targets on the right temporal lobe, few on the left side and frontally on the left side as well. You can go to the next slide.

- I'd like to interrupt you for a second here. We've just not found the ability to get the MAYFIELD in a way that avoid the robot. When I wanted to do bilateral, I have tried a number of different configurations and I've just not found one that satisfying mostly to try to get the contralateral temporal lobe. So it looked like on that, if I got your configuration correct, it was... Looked like the majority of your electrodes are on the right, you had a few on the left. This is exactly the kind of case where I've tried with... Trying to get the double pins in such a way not to interfere with the robot has been a challenge. How do you put your MAYFIELD on in order to avoid that? And then I don't anchor the robot to the bed, but to the frame as it is. And I've not been able to get it so that it then doesn't interfere with the star registration configuration.

- Yeah, this was a challenge. So what I do for bilateral cases is the double pin and go very low on the occiput in the midline, straddling the midline, single pin goes on the forehead as low as possible, taking care not to violate the... Or be at the level of the frontal sinuses. And then we angled the MAYFIELD down quite a bit, almost so that the arm is... The connector arm is below the ear. And that can give you the clearance necessary to get the robot into the bilateral temporal areas. 'Cause I think on the convexity or frontally or parietally, you can get it, but it's really the temporal areas where you have the biggest challenge. The reference frame is then put in the midline, so high on the midline. And then the arm on the bed does allow you to minimize any motion on the arm on the MAYFIELD, that is. So I had to become more of a fan of putting the robot on the bed, I think it's a little bit more rigid than on the MAYFIELD. I think when you've got a lot of weight, you've got the patient's head, you've got the reference frame and you've got the robot, they all essentially should move together. So if there's movement on the robot, there's movement on the head, but I like to see no movement at all. So on mounting the robot to the bed, I feel a little bit better with that. One idea we've come across that we haven't employed yet, but you can also put the patient in a frame for a Leksell frame or CRW frame. And if you have that frame rather low, you can attach that using a MAYFIELD adapter to the bed. And then that should give you the clearance for the robot.

- And how do you attach the robot to the bed? I didn't see that in your setup there.

- There's a bed adapter, so, and there's a Starburst bed adapter for the frame, for the robot.

- Yeah, for our bilateral cases, I'll interject, we actually put them in the MAYFIELD exactly like you did, which is a single pin and then the double pin across the back. What we'll do is we'll do one side at a time. And the way that we drape it out is that we have a body drain that is underneath there in the clear plastic drape. And so what we can do is do one side and then with the patient in the MAYFIELD, just unlock the MAYFIELD and then just turn the patient's head, 180 degrees. So, that may be configured like this and for the electrode placements, and then we just flip them 180 degrees. It does take a little extra time where we would be able to... I have to re-register and re-drape, but we just found that that created a little bit more efficiency than trying to struggle to get to the other temporal lobe or those kinds of things, so.

- I agree, I agree, those are good points. And I think bilateral cases certainly are challenging, but whether you're using a frame based approach or a robotic approach. And if you have to undo the drapes and go to the other side, it's certainly very reasonable to do that.

- Right.

- So again, showing our co-registration, taking an O-arm spin, merging with our preoperative imaging, another example of accuracy across one of the... This looks like an electrode in the left amygdala. Looking both at the probe's eye view in the right upper hand corner and the trajectory views. You can actually see how the electrode, one of the contacts at the end does deflect slightly. So there is, although you have a rigid stylet within the electrode, there can be a little bit of wiggle. So, Dr. Adelson's point about maybe taking a K-wire to target, I think that's a very good point. You can go to the next slide. Again, here's another case of a bilateral electrodes, a temporal coverage on the left side, some parietal coverage on the right and temporal coverage on the right as well. Go to the next side. Again, showing accuracy of this patient. And I'm selecting one of the parietal electrodes. And you can see here, we have a little bit of an error. And although our entry point was quite good, as we get deeper through the electrode, we're off. Next slide. What's nice about this and the reason I put this slide in is I can then go to my neurologist and say, whether this was targeted based off a MEG cluster or a structural finding on the MRI, I can show them this picture and say, "Is this acceptable? Do you need me to replace this electrode? Or are we in the range?" And in this case, we were close enough that it was acceptable. But we were able to tell we were about 1.4 millimeters off target to intended target. So that's the utility of being able to merge the scans. So this is a case of a laser ablation with a biopsy. Some of my colleagues stage these cases, there's a little bit of concern of introducing air, which can then create distortion during the ablation. There can be steam events or interference on the thermography. And so this was an example of a patient who had a low grade lesion within the amygdala. I chose to biopsy it through the temporal lobe and then do the ablation in a traditional MTLE sort of approach. So this is the position I used. I had the patient in a MAYFIELD and here's the position of the robot, which did allow us to get to both trajectories and from a single position. Here is our initial registration accuracy. And here is the placement of the laser fiber. So we took the post-op scan and merged it with our initial plan scan and you can see we got a really nice accuracy through the fiber. Go to the next slide. And here is the result of the ablation. So we were impressed, there's very little pneumocephalus. And I think that has to do with the small opening through the bone for the biopsy. If you're doing larger open biopsy, if you're using one of the other systems like navigus based biopsy, I think there tends to be a little bit more pneumocephalus, but it was nice to see very little pneumocephalus in this case Again, showing our ablation scans here and our DTI sequence.

- If I could comment, yeah, that's a fascinating approach. We do the biopsy through the same window. And I would agree that occasionally, we get some of the air artifact because of that. I had a case recently where that was indeed the case. So having two different trajectories and as accurate as possible without that error might reduce the risk of that. So I thought that was an interesting approach, not one that we've pursued yet.

- Thank you. This was one of our frame before we had the robot we were placing our laser fibers via a Leksell frame and showing how accurate the targeting was, of course, with the frame. But it's a nice comparison to see going from a non frame based approach, we're able to still maintain good degree of accuracy. Next slide.

- Just a quick question. Do you tend to do your plans the day of surgery or the day before? We have a workstation that on, first let's say, complex cases or the ones that I really want to battle with back and forth, I will do them the night before. Particularly, like a DBS case or like a deep RNS hybrid kind of case. Whats your experience with that?

- Yeah, we recently acquired the remote planning station and we love it. It allows the neurologist and I to sit in the same room. We usually plan oftentimes 10 or 14 days prior to surgery we order electrodes as needed, so we pick the appropriate electrodes. But it's really nice to not be in a rush the morning of to pick plans. So we do it together. We pull up all of our functional imaging, if we have a MEG, if we have tractography, if we have other functional scans, an FMRI, and with a cup of coffee, take our time and really think about the case. And it's not just planning the case, it's thinking about this patient's... What are our intended goals? So that's been a huge advantage. So, for me, ensuring that I'm being safe is the most important thing. Making sure not crossing any blood vessels or if I'm crossing that I'm willing to live with that risk. And we've been fortunate, we haven't had any hemorrhages, but every electrode you place has a little bit of a risk. So I'll often plan and then go back two or three days later, look at the plan and say, "Oh, this is not acceptable, I really need to be further away from a blood vessel than I was." So that's our workflow. We used to plan a couple of days before and/or sometimes the morning of, and I think it's less stressful to plan a little bit further in advance.

- You're a better man than I am. I don't think I'd have the patience to sit with my neurologist, even with a cup of coffee. What we do during our conferences, they give me a listing of electrodes of where they would like to have their studies and where the hypothesis is and we do go over that. I create a paper map and then I go in and put the electrodes in. And as I said, if I have a morning where I can get down there and plan out all the standard electrodes, I'd do it in that way. But, you're right, it does add a little bit extra stress, but it also... Doing it in advance, it's often difficult the day of surgery to just run in and use the plans. We have the remote workstation, but we've had some issues about getting the images sent over and I've had to do on one case where I had to redo the plans based on my memory of what I did. So, I think there's pluses and minuses to both.

- Thank you, thank you so much, Dave, really, a very productive discussion. Manish, thank you for joining us when you have an urgent case going on and just joined us, thank you. Manish, may I please ask your opinion, which I asked Dave and Vik as well. What do you see as the pitfalls of using this device in early learners? Would you mind sharing that with us? I know you have great experience using this robot.

- Yeah, thank you so much for having me, Dr. and Dr. Mehta and Dr. Adelson. I had the unique privilege of using the robots as well at our institution and we should be shortly publishing our series about that. And as you know, with such a small robot the worry is that there's going to be a lack of rigidity in comparison to a gigantic robot. I think Dr. Mehta gave a spectacular presentation in the comparison of the weights of the things and they share the size and comparison. So, the entry point rigidity, the rigidity affects the entry point error greatly more than probably the target point here. And so this device, as long as you can find a way to make it almost as accurate in entry point, especially for non orthogonal entries, it's basically as good as any other robot or frame system out there. And it has the benefit of being substantially cheaper. So, that in concordance with the fact that the vast majority of us have some kind of neuronavigation software experience, that our institution between our residents and staff probably at least, a large percentage of maybe it's half, half, maybe it's one where the other have the Medtronic Stealth system available. The experience with planning and operation makes this robot easy to use. From the beginning to now, we've probably done about 15 or 20 cases, and we've put in about a similar number of electrodes, biopsies and laser ablations. As Dr. Mehta says, we've drastically reduced our time for placement by custom making reducing tubes to fit our specific electrodes or laser ablation, things that we're gonna use, and we found that to be very helpful. And so that has helped a lot. We use checkpoints before we do certain non-orthogonal entries that are critical. As all of you know in robotics, the most critical thing to do is avoid a surface vessel. Those vessels are stuck to the dura, and they're very hard to move around. Usually, the sulcal vessels and the deep vessels get out of your way. And so if you can plan, and unlike Dr. Adelson, I think I'm more in Dr. Mehta's camp, I have to plan with the neurologist each lecture. And so we have the poor man stuff planning station. I have a resident or myself FaceTime the rest of the gang with Zoom or WebEx, and they just show me and then they... Or hopefully just the stealth. And then we sit and modify any electrodes we've already planned. And then the day of surgery, we get another CT with and then I just... I'm a paranoid finicky person and I go back and make sure we're not getting any surface vessels that day. So that's been my experience and I've been very happy at use this robot over the course of last years. It's much easier to use in terms of its software. And it's helped a lot of children.

- If I may ask you a question, I think may be you should referred to it, number one, the learning curve, how many cases we need to do to really get comfortable with this. And for the rest of the panel, if I may ask, what is your experience with this stealth and integrating robotics into a new platform that you may have already known about? If you could comment for those, Manish, first, I appreciate it.

- Thank you, I'll just say a couple of words. I know the other guys have excellent experience with this. At our institution we have a robotics committee and for each robot you have to do five proctored cases before you can do a new case. So Prof. Tandon is at my institution, he uses the robots a lot. I did five proctored cases with him and learned how to use that device. And I think basically it'd be about the same for this Stealth Autoguide if anybody wanted to use it, I would proctor them for a few cases. There are certain things that no one wants to see their colleague make the same error. So, thank you.

- I think that the... Again, the integration with Stealth and the Autoguide, really do marry up well. And it was really an opportunity for us to, as I mentioned earlier, I didn't have to learn a new software and new technology, so that really helped the learning curve. But I really felt... Unlike Dr. Mehta, we, our first case was an SEEG case, so that I could do 10 in a row. And we did improve our accuracy, the first one was quite slow. It was about the same as using the Vertek arm. But then, really, by the last series of electrodes that we placed we were down to the similar accuracy of about four to six minutes. So, I think the learning curve-- And that was all within one case, so. And we did have to fine tune certain things. And some placements are more technically challenging than others. The orthogonal temporal ones are not as complex. And I think those are the ones that... Or the biopsies. I found that doing a single, the laser or the biopsy, since it was a single placement, we tended to take more time because it was a single placement rather than sort of the repetitive that you would see with an SEEG. I would also echo Dr. Mehta's experience with having an experienced team. For the most part, I use the same people when I use the robot. Because very frequently, let's use the SEEG as a perfect example. We'll actually move to... Once we've placed the anchor bolt for our SEEG electrode, we'll actually move the robot to the next plan. And my assistant will be setting up everything and actually start the planning process while I'm placing the electrode through the anchor bolt. So, we've really cut down time between those electrodes and in order to do that just by creating this smaller efficiencies within the procedure itself.

- I agree, I think, with Dr. Shah and Dr. Adelson, both, all those comments they'll re-echo with me. And I was... I found it very easy because we used the Medtronic Stealth platform to integrate the robot. It was seamless, so I liked that. So planning was very straightforward. I think, starting from starting with a biopsy and having a backup, just helped me alleviate some of the concerns about potential initial problems, so. But I found that the learning curve on the biopsy was very, very easy. You basically target, you make your hole, you drill, and the biopsy needle and other equipment its the same as the other platform. So there's no difference in the technique of the biopsy. But the SEEG, if you're doing five or six electrodes, you might... And you don't have a second case that day, you might take your time and not worry so much about the efficiency. But if you're placing 15 electrodes and you've got three other cases to do that day, you're gonna be thinking about, "How do I get this done safely and efficiently?" And that's where I think a lot of the learning comes in, its how do you make it efficient while maintaining accuracy?

- I guess we have to emphasize that this device has been out just for a year, and this is the initial one-year experience. So that's an important point there. Vik, would you like us to go over your other cases? But before we do that, Manish, do you have anything else you wanna add that you feel is important in using this device?

- Nop, thank you, I agree with the comments that have been made.

- Thank you. Let's go ahead to your next case, please.

- So this was an interesting case. My partner sent me this case patient with a right temporal GBM and had standard therapy ended up having gamma knife to new area of recurrence just adjacent to the lateral ventricle and was doing quite well. And so our oncologists were interested in laser ablation for this patient. So you can see just adjacent to the ventricle, the small, new area of enhancement. This was not found to be consistent with radiation necrosis, given its location and the patient's overall condition, they asked me to consider performing the laser ablation, which we did. We can go to the next slide. We can see the result of the ablation scan. So, we started expanding into the oncology indications, cavernous malformations, say, something that's about two and a half centimeters, you might be able to get away with just doing the laser ablation. So, we're exploring. Team to be very interested, especially in those patients who are functionally not doing well, who may not be candidates for a larger open resection with... Their eyes are definitely on this technology for palliative and local control of the brain. Here's our post ablation scan. So I think when we talk about the learning curve, what are the expectations? I think it depends a lot on whether you've had prior Stealth experience. If you're comfortable with the workstation I think it's... The learning curve is very easy. If you've had a prior stereotactic experience, whether it's frame or frameless, it helps, the principles are the same. Verifying or confirming how accurate you are involves all of the subsequent steps of the preparation of registration and your technique. So, those same steps apply. If you've had any type of prior robotic experience, whether it's spine or cranial, it helps. You're essentially looking on the screen, doing the surgery. And if you're a cranial micro-surgeon and you're used to working through the microscope, it can be different. And so if you have some experience using robotics, that does help. If you're using an established workflow, just using a different platform to do those steps, where if you're learning SEEG or you're learning stereotactic biopsy for the first time, there's gonna be a different learning curve. I think if you're performing intra-operative CT confirmation, it helps. I think getting that real time feedback on your accuracy, it helps build your confidence, your team's confidence and can give you feedback on how to make small adjustments to improve that. And, things like incision planning techniques, whether you're making a larger incision or you're floating the drill guide, those things you'll develop on your own with whatever you feel comfortable with. There's nothing new about the robot. You're doing the same thing, you're doing the biopsy, you're placing an EEG electrode or you're placing the laser fiber, it's just a different way of targeting. So keeping in mind that the surgery is the same, you're just using a different device. Some technical pearls, just a list of things. I think we've gone over a lot of these things. But in general, pre-op stealth CT, I think that gives you much less registration error and improves your accuracy and allows for more accurate O-arm merge, if you are doing a postoperative O-arm spin, you could also use bone fiducials, post O-arm placement, at least initially, to compare your plan to the placement helps you build confidence and you modify your techniques as necessary. I started with an easy case, I did a right frontal biopsy and moved up from there. And I think you may wanna pick something where you have a backup, if you have a technical issue that you can easily convert to a familiar workflow. The six inch protected bovie tip for the skin is what I use and then the six inch needle tip bovie in case the dura is not open. We haven't talked about this, but if you have a non-sterile Autoguide tracker in your tray, you can actually plan the case and ensure that the position of the robot and the patient's head are all accessible, if you're doing contralateral approach, or if you're doing unilateral approach with electrodes that have a great distance between them. For example, if you're doing an anterior temporal tip electrode, but then you're also doing a posterior parietal occipital electrode. Before you drape, you can ensure that your robot is not going to collide with the MAYFIELD or having any other issues. Doing a dry run is always a good idea, get your team on the same page. It's new technology and fairly different from what you've been doing, it's nice to do a workflow. One of the things I learned from Dr Adelson's talk was there's a five-second magnet lock. And so once you've targeted, if you're doing 15 electrodes, you might be in a rush to get them all done. Just give it that five seconds for the magnet to lock and that will improve your accuracy a little bit. For SEEG, we did a case where we planned and we decided to go posterior to anterior and we realized that it's a lot easier to go from front to back to avoid collisions with the existing anchor bolts. We float the drill guide and use the bovie on cut, we minimized the skin incision, there's essentially no bleeding. The drill guide-- I'm sorry, the drill does max out at 14 millimeters. So if you need to go deeper than that, the bone thickness or the skin distance is greater, then just have a standard 2.4 millimeter drill, a hand drill on standby. And develop your workflow. So one of the things that helped us move much more quickly is once the anchor bolt is secured, my nurse practitioner will pass the electrode while I'm moving on to the next target. So if you have residents or you have mid-levels, you can do this in tandem, and that will greatly improve your efficiency time. So she'll pass the electrode and plug it in to the connectors for the Intraoperative ECoG while I'm moving on to the next target. So that can help. For biopsy and Visualase, I think it's okay to do the biopsy at the same time. I think the concern of pneumocephalus is there, but you can really minimize it. You can always place the laser fiber first and then do the biopsy. You wanna trial the robot to ensure that it'll reach. you can move the robot on the Starburst to different position under the drapes. And then again, O-arm to confirm, can help you prevent a trip back to the OR if your fiber is not where you'd like it to be. So I think robotics and neurosurgery is the future. We see this in spine, we see this in cranial application. I think the system is highly accurate, it's very versatile. I love the feature of the continuous navigation. So, when I've put the drill in, when I put the biopsy needle in, I'm getting real time feedback on whether I've introduced any error or not. It seamlessly integrates with the StealthStation, which is the station I use, so it's easy for me to work with. There's a small footprint. It makes it easy for the OR staff, you're not driving in a huge robot. If you're doing two cases in a day, it's fairly manageable. And I think the learning curve is manageable. I think if you're familiar with these cases, you're not gonna have any problem. If you're learning SEEG or stereotactic biopsy for the first time, I think within five or 10 cases, you'll be fairly comfortable with the workflow. And again, that continuous navigation really gives you a high degree of confidence about your accuracy and your safety, Dr. Adelson, Dr. Shah, any comments on closing?

- Excellent discussion. If I may ask a couple of questions, Manish, can you let us know how different is the learning curve for Autoguide, in your opinion, compared to ROSA or bulkier robotic stereotactic systems?

- That's a great question. I think they're all pretty comparable. It's like I said, if you are able to do five cases with somebody who knows what they're doing, it's gonna be much better. Obviously, the Autoguide has only been around for a year, but I'm sure they feel the same way. If you guys have questions, we're a phone call away and we're always happy to help. I think in terms of what Dr. Mehta was saying, you should probably try to start with an easy case first, I actually started out with doing SEEG and I was using the workflow that the company advised. And, it turns out that just the way our electrodes are and such, we ended up modifying that workflow and making different reducing tubes. But there are various ways to do this and whatever the equipment is that you're going to use, that you're gonna place in the patient, that can kind of dictate and drive the way you want your workflow to be. And there are plenty of people who have experience, so we don't repeat the errors that have been made. Please reach out. And I know that Medtronic is really excellent in putting all of us in touch. And so that would be my advice on reducing the curve and making it less steep for everybody.

- How many cases have you guys done so far? Or how many cases do you need to be really comfortable? Let's put it that way.

- Well, we started using it really, when it came out. And we're now a year plus out from its use. I really think it's really an integral part of our operating room now for all of our stereotactic cases. We use it very frequently. We use it for all our SEEG cases and we do a few a month and as well as laser ablations, which we do a few a month. So, I mean, we've done probably at least, 70 to 80 cases now with it. And I think that we are still learning on it. And I think that our efficiency and accuracy gets better. And actually, because of the other individuals here, I'm gonna try to incorporate some of their ideas into this and see if we can knock off even a couple of more seconds. I did want to clarify, we've been told that that five second delay is the locking, but it's really a monitoring. And recognizing that if we are off accuracy as Vik had pointed out, with that drilling, we're able to correct in real time the navigation to make sure that we are accurate. Because it's a smaller device and as I think as Manish pointed out, it seems like it shouldn't be as rigid because it's smaller and it's connected to the frame. But I think that having the real-time monitoring is important.

- Got it. Okay, those are such valuable comments, Dave, thank you. Vik and Manish, do you guys want to have your sort of final lap pearls of technique tools on spoken secrets about using this robot and improving its efficiency? So for people who do this procedure, what is your recommendation, to switch to this? Or advantages/disadvantages, if you want to have the closing comments. I sincerely appreciate.

- Yeah, I think if you're happy with your workflow and your equipment, the robot will help you achieve, I think, what you're doing with the other platforms. So there's not necessarily a reason to switch, but if you don't have a robot and you're looking for something, I think it's an excellent option. There are other options, we found that this was the right one for us. I think there is a community of people who are doing this. And it was very helpful for me to listen to some of the talks by the people who developed the robot, by Dr. Adelson and learn about the techniques and share feedback with others and incorporate that feedback. It's new, and so I think, gathering all that data and opinions is really helpful. I think what Manish said is exactly right, is don't make the mistakes we've made, learn from the errors. And overall, I think even for a very novice user, this can be incorporated into a practice pretty rapidly.

- Okay, thank you. Manish, do you have any other thoughts please?

- No, I think I'm-- All the great words have been said. But just don't hesitate to reach out and try to plan shorter cases. And, the first time you press those two buttons, that blue home button and the robot goes to where it's supposed to go, you suddenly forget all the pain and suffering that you had with the Vertek arm or the frame and makes you never want to use them again. So, we're quite thrilled.

- Thank you.

- One last comment is that obviously, the attaching the robot to the bedrail is at the discretion of the surgeon. I don't believe that's necessarily something that's written in the manual of this device, just as a disclaimer. So with that in mind, I wanna thank you very much. I'll again, mention to our audience that all our esteemed speakers are available as a resource for using this device. And I think just like anything else in neurosurgery, we have to get some experience and robots are here, they're here to stay. They're definitely gonna advance our workflow. And as you go through more cases, you're gonna find these devices to be even more and more effective and have a bigger potential in the future. So again, David, thank you for being with us and making the time. Vik, thank you. Manish, thank you with being on call and making the time to be with us at the end of the talk. And I wish you guys a great evening. Thank you.

- Yeah, wonderful to see you all. I hope to see you in person soon.

- Thank you.

- Thank you. Thank you all, bye-bye.

- Thank you.

- Bye.

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