It's a real pleasure to introduce the scientific session number two, focused on the spine. I'm Zoe Gogowalla coming from Boston, and I'd like to first introduce my co-moderators, Dr. Mike Steinmetz, who is a professor of neurosurgery and chair of neurosurgery at the Cleveland Clinic, and Dr. Michael Wang, who is professor of neurosurgery at the University of Miami. We have two world leaders in robotics and navigation to lead our discussion this afternoon, Professor Nick Theodore from Johns Hopkins and Professor Juan Uribe from the Barrow Neurological Institute. So again, a real pleasure to have everybody, and we're gonna get started with an open discussion conversation between professors Theodore and Uribe on the topic of navigation and robotics. So Dr. Uribe and Dr. Theodore, take it away. Thank you. So Juan, I'm curious as we get started here, when you started using navigation, did you start in residency with spine or after, or when did that evolution start in your career? Yeah, which is very interesting, Nick. You know, like most of us, we start using x-ray for everything, fluoroscopy, heavy fluoroscopy. And if you do an MIS, you know, you go home every day at night and you're basically glowing in the dark, you know? It's so disgusting. And, you know, when you're early in your career, you know, navigation was just starting and I got exposed to navigation near 2007, 2008, around that time. And I give it a try and it was a little bit hard, Nick. And because I was doing good with the fluoroscopy and the outcomes were good, you know, we always err on the patient side. So, but then I can tell you on the last five years, my practice changed dramatically. So you ask me today, I will say 90 plus percent of my cases, I have navigation somehow in the case, you know? Sometime I use the x-ray as we call Sentinel, but otherwise I think I can tell Nick, you tell me if I'm wrong, in five years, almost everybody will be somehow navigating. See me that will happen with the brain. Remember when brain navigation came, you know, 15, 20 years ago, people were laughing like, oh, convexity meningioma, why you need a navigation for? BP shown why you need it. Today, I bet that if you have a convexity meningioma and the navigation system is damaged, I can tell you that the case get canceled. So I don't know, Nick, what you think, but. We, I mean, I agree with you a hundred percent. I mean, image guidance came out really when I was in the beginning of my residency and I remember doing cases where we were localizing with our finger and it dawned upon me that obviously once we have that technology, it did change everything. And all the push was for cranial, I think at the beginning and the workflow was better. I remember early on with image guidance in the spine, and this is where I think a lot of people got lost, was that it was, it disrupted our workflow and it took a lot of extra time. And if you recall the point-to-point registration where we had to touch the spine, touch the spine's process, then find that mark on the CT, touch a facet, find that mark on the CT. And the reality is that that took an hour and added an hour to the case. And I think we lost a whole bunch of people. Roger Hartle wrote a beautiful article, it was about 2013, showing there's about 10% adoption of image guidance in the spine at that time. And the reality was everybody said it was because of disruption of workflow. So that's gotten better. And to your point, I think just like in the cranial, I think the numbers are now rapidly increasing. And I think part of that has to do with our trainees and we don't really have as much time with them as we used to have. And they have, the millennials certainly seem to be adopting of this type of technology. Not that supplants the need to know anatomy and anything else, but the technology that could potentially enhance their accuracy in any given procedure. Nick, can I explore that a little bit further perhaps with both of you? How have you found navigation helpful as you teach residence procedures? So, you know, Zoe, that's a great question. And I think the paradigm is switching. I mean, I learned, we opened everybody up and we saw the anatomy and we touched it. And, you know, we sat there for hours contemplating over where the entry point was going to be. And the reality is now, number one, since things are condensing and we don't necessarily have MIS, since we're doing more minimally invasive, we have less of the opportunity for those big exposures and those big opportunities for them to learn. So I think what we're moving towards is a hybrid where there's going to, we all have to know the anatomy. That's the key. And Dr. Sontag taught me that you don't leave the operating room, you have to know the anatomy. And the fact of the matter is that once you, you know, so we're going to teach that with cadavers and with image guidance, with planning and everything else, you're going to have to understand. And there's going to be a trust, but verify policy with image guidance as we get better. The paradigm switching, same situation applied. You know, are you off with the cranial navigation? You need to know if you're off. If you're touching the right here and it's telling you you're in the pineal, you know, you're not accurate. We have the same checks and balances in the spine. So I think it's just a different way of learning things. People who say that it can't be adopted because we have to teach it the old way or what happens if the technology breaks. I think we're going to be past that era because I think it's becoming more robust. I don't want to say people are becoming more reliant on it, but they are, but they'll also know checks and balances to make that paradigm safer. So from a teaching perspective in the millennials, it's pushed me every single day to try new things and to make us better at what we do. And that includes teaching. Well, can I ask you guys a question? You guys are both at premier academic centers that are well-known for their expertise in spine and neurosurgery. For the average neurosurgeon out there in a community hospital, you talk about a robot or a nav system, and you're talking something like a half million to $1.5 million capital equipment proposition or something along those lines, right? How do you guys approach that? You know, maybe like, well, I want to buy this system. How do I approach my administrator or which system do I choose? How do you guys address that? Maybe start with Juan first. Yeah, that's a really good question and it's very provocative, Michael, because this is something that every surgeon that is right now practicing will face at some point on their careers. So you cannot deny what is the truth. Technology comes with a price, yeah? And we live that with the iPhones, with the phones, cell phones that were extremely expensive. Let's see, for example, the flat screen TVs where like only the royalties can have it and now you can get in the corners. That is similar to that. The thing is that part is a process and the process has to move. And we jump at different stages on the wagon, let's put it that way. And because of the Nick work, you know, the pioneer of, for example, they say on the robotics and navigation, if that step was not performed, it will never be where are we right now. So the question is, how can you justify million dollar toy, as they say, just to guide you to put a screw? Because this is what you listen on the bad side when you're trying to block the adoption of degeneration. But I would say that when I was using the robot, what, four years ago, Nick, 2016, 17 was commercially came available. I mean, it was like a big show, the case. You know, it took forever, all the flow. But I can tell you today is actually putting, make the robot working with navigation. It becomes almost a flow, similar to what you were doing before. So I would say you had to convince your administrators that actually in your investment, not only in the patient's outcomes, but also in the safety of your OR team, the lack of radiation exposure, there's a lot of benefit that comes with new technologies. And specifically, this is opening the window for what is coming that is gonna be even better. I would say we just scratching the surface of the potential of this. And when Nick was mentioning Dr. Sontag today, you know, when we learn from Dr. Sontag and our pioneers, you know, at that time, navigation was just like a concept, like a flying cars today, you know? And you're very ahead of everything, Mike, as well. And you see today, if you ask Dr. Sontag, one of them, they will absolutely endorse you to get into. Same thing like they were fighting with a pedicle screw that they say that was the worst thing ever. And take a look, where are we at? Can we do spine without pedicle screws? And I have a surprise for you. Take a look, what do I have on my side? Hi, guys. The greatness of the greatness. Hey, good to see you. What do you think, Nick? I love it. I'm jealous. I think that, you know, I think you hit the nail on the head. I think the other issue, Mike, is that the adoption of the technologies from the surgeon, right? I mean, you're not, nobody's convincing or strong arming anybody into doing anything. Surgeons have to understand that this is gonna help them. If it doesn't help you in this stage in your career, if you can do it, you're doing everything open or with x-ray and that's the way you do things safely, then so be it. But the change, the sea change is happening with the younger generation. They're in the operating room. Again, they're not on call every other night like you were, Mike, and Juan, I was, and they don't have the hours. We're gonna talk about the 10,000 hours, whatever it is, for spine surgery. That time has collapsed now. They have so much more to learn in endovascular and functional neurosurgery, peripheral nerve. Our specialty is so complex that when that time gets collapsed, we have to have something that enhances their ability to do some simple procedures, even more complicated procedures, and Juan's right. But it is gonna be driven by the surgeon at any given juncture in time. I think that's where the movement is happening. Nick, speaking of being driven by the surgeon, could you share with us some of the thought process in your mind? You have been a innovator and a leader in developing robotics for neurosurgery and for spine surgery. Can you describe the beginnings of that and some of the things that helped you develop robotics for our specialty? Sure. Well, I mean, I really owe everything to the man sitting at Juan's right, to Volker Sontag, who taught me really the basics of spine surgery and was always an early adopter. Whenever we wanted to do something new and image guidance came out and Robert Spesser was all on board with that, we were coming along for the ride in spine. You know, the spine wasn't really the focus of image guidance at the beginning, but the reality came when we saw what it could do. The question was one of attention. And what I always talk about was we're looking at once, and whether it's brain or spine, you're using image guidance, your head keeps turning around to the screen. Every time your head turned, there's an attention shift. The hand moves a little bit. And the basic question that was posed was, can we automate that accuracy? Can we take us to that point where we don't have to be looking back and forth and being chained to the machine? In other words, as your hand moves and your head moves. And that was the very simple, basic premise. And Neil Crawford, who was for years the chief of biomedical engineering, biomechanical engineering at the BNI. And I really started this project on nights and weekends over the course of 10 years, 15 years actually, of seeing how we could actually use real-time image guidance and marry it with robotics. And Juan is exactly right. Right now we're putting screws in. He's also right that not in the long too distant future, these machines will help us with decompressions. They are going to help us with osteotomies. They are going to help us with the more complicated things that we do. We're already navigating inner bodies and things like that. But the journey really was one of persistence because the reality is I thought there was a need and I'm glad it took as long as it did because I think if it had come out five years earlier or when we had more missteps, it would never have reached the adoption. Now we're looking at, when you look at robotics now in spine surgery, there's probably 400 plus units of all robots placed worldwide, which is a lot of cases, 70, 80,000 cases now done with robotics. I'm talking about all comers. And that number is continuing to grow every year. So I think we're close to getting across that chasm. But if you had asked me 10 years ago, it was a slug. And the fact of the matter was we never thought that it was going to, you always have doubts about everything because everybody does things their own way. But it's been reassuring to see that we're all getting to that point where technology is becoming part of our lives, not just the iPhone, but robots. some image guidance. Nick, I've got a question from the audience and I do want to just let the audience know to please use the Q&A button on the right side of your screen if you would like to ask a question to our panel and you could also use the chat button that's going to interact with the rest of the folks in the audience but use the Q&A button for questions. So Nick, this question is addressed to you and it's from Eric Knottmeyer who'd like to know if and when robotic surgery will be used for laminectomy or I guess other forms of decompression as well. So Eric, good to see you virtually. The answer is 100% yes. The drawback and the fundamental question is who's controlling the drill and the end effector. The FDA pretty much has a hard stop for autonomous surgery. They are not going to allow a free floating arm to do a laminectomy even though that would probably be the most precise way to do it. The FDA is not quite ready for autonomous surgery yet. So the reality is how are we going to plan and conceive of that so you can imagine robot taking you to a trajectory and you doing the drilling and taking it down to a millimeter of bone left. So that will happen absolutely. It's a little bit more complicated than the screw paradigm because again we're now dealing with three-dimensional geometry whether it's a laminectomy or a facetectomy or a pedicle subtraction. It will happen. I'm going to tell you probably in the next three years we'll see that coming out as an offering. I've got a question for both Nick and Juan. Really focusing on robotics and going back to I think Mike Wang's question around purchasing. So you know when you talk to the robotic, so who has a robot out now? It's often like what's coming up next? Like you know what's the next iteration? What's the next technological advance for the software? In some hospital systems there's a question that's been focused around when to pull the trigger, right? When is it mature enough to go out and buy one? And I know that's not an easy question to answer but can you at least discuss it, right? Because some people were very early adopters bought the you know first gen robot and others are waiting for whenever it's quote-unquote developed enough and like when is that? And you guys are both adopters so maybe that's a bad question but maybe just discuss that concept for the audience because I know a lot of people are facing that. Yeah and that's a really good point Mike but the question is I like to make comparisons which is easier to digest. So a question for example is let's say on cars right now. Are you ready to buy the electric car? You know when the first electric car you know the Tesla came there was a lot of skepticism and today you know people are getting more and more. So I'm gonna send the question back to you Mike. Are you ready to buy the electric car or you think the world is ready for the electric cars? If I ask you today, if I ask you five years ago. Yeah you know I think the world's ready now. I mean I think it's much more accepted than it was maybe five or plus years ago and I think it is sort of this glass half empty, glass half full. If you could spend your whole life waiting for the next iPhone or simply buy it knowing that a year or two it's going to be upgraded and it's almost a mentality issue. I think with robots at least in my impression is you're going to have to buy a version that's mature enough and this is my take on it and knowing you're going to it's going to be upgraded, the software is going to be upgraded, the end effectors may be upgraded but in my opinion it's mature enough. I mean it's no longer a first gen device right. It's been multiple generations of and Nick as you just pointed out thousands and thousands of cases showing that it'll work, but again, you still talk to people that look at a robot simply as a robotic screw, device to put a screw in. They don't see all of the software, the planning, and what's next? I mean, augmented reality, predictive analytics, whatever's next. So I still think there's, that being said, I mean, you put the question back to me, I'm gonna put it back to you and Nick again, is that still, I still think you have a half of the surgeons or more that are still questioning, is it mature enough to buy this? Yeah, and it depends on where you are in your career. Right, I mean, I've given this presentation, you know, LSRS and talked about robots all over the world. And the reality is that when you are in the last two or three years of your career, probably not gonna be an adopter. And if you're mid-career and things are going great and you have a workflow, whether it's image guidance or x-ray, you're not gonna, you may not wanna change. So again, the driving force is the surgeon. What I see though, is when I can take a junior resident through an MIS TLIF in two hours and watch the screws go in perfectly and then guide them through the decompression part and teach them that the more critical part of the case and still get the case done in two hours, that's a game changer. Because again, in, you know, a lot of MIS sort of went by the wayside when it was difficult to teach trainees, especially more junior level trainees, even the basics of what we were doing. So that's why I think when they started adopting it and they realized, okay, I think I can do this and then understand how to do it safely, that's where things change. So again, all driven by the surgeon. But it's time for the Tesla. Yeah. And Mike, remember when you started doing the mini open TLIFs and the, you know, working with the tubular decompressions and, you know, comparing to the standard open one level posterolateral fusion that will take half of the mini open TLIF, how would you went through that core, Mike? And do you see that similar to the robotics and navigation or you think we're dealing with different animals? Is that for me or Mike Steinmetz? For you, Mike. Yeah, I mean, you know, I gotta tell you, that's one of the big onerous things about trying to teach people is that those trajectories aren't so easy. And as Nick Theodore was saying, like being able to guide a trainee through this with greater confidence and not just have to take over the case for them. They're working with the robot, the robot's working with them or the navigation system or the AR system. It's really, I think a wonderful teaching tool, but to what everybody said before, you also need to know the anatomy, right? So it's tempting and I've done this before. I've been guilty of this. I start teaching them this way and they get too accustomed to it. It's kind of like the brain guys that can't do a craniotomy without the stealth that's happening now. They can't even find like the right or left side of the head. And I think I heard about a case like that, that they couldn't figure that out, right? We don't want that trap for sure, right? Because that's dangerous. But I do think it is a very, very interesting way for people to see the anatomy differently. They can see it the traditional way, this new way, and it actually might make them even smarter. Hey, thanks, Mike. I've got another question from the audience. I just want to remind everybody we've got about five minutes so we'll probably be shut off then. So we'll try to monitor that. But question one was directly to you around navigation for laterals. Are you using it for your lateral approaches? And if you are, can you talk about how you use it? Yeah, so that's a great question. Actually, it will be a great venue for the next session, which I'm going to show doing a prone lateral with navigation, which I think is essential for this type of case. The answer is yes, navigation loves lateral because having the actual view of the spine and you able to define where to dock your dilator in the psoas, it makes a big difference, you know, in terms of avoiding vascular or lumbar plexus injuries. So I think what you mentioned before, Mai Wang, is that I see it with my fellows. They come from programs where they don't do too much navigation of MIS techniques. At the end of the year, they don't feel confident putting a PAYCOL screw that is not navigated or percutaneous. They feel that, for example, S1 screws, they feel that they do a better percutaneous or navigated than open, which is very interesting, you know? Once you get through this and make it flow, you get addicted to it. There's an additional question from the audience. I'm just going to read it verbatim. This is for you, Nick. It says, what is the advantage of a robot in a laminectomy if it can't limit exposure? Well, first of all, we're not using it for laminectomy. When you say it can't limit exposure, I guess I don't know what that means. The part of the, one of the challenges I will tell you, though, is that it's beautiful for percutaneous. Sometimes we struggle with some of the open cases because of tissue deflection. If we're doing a revision case in a 400-pound person, that's where things, even with robotics, run into trouble, just as getting those trajectories saved. So, you know, again, it's, there's a, it's a very interesting, the learning curve is different for everybody. If you're purely MIS, it's easy. If you're an open person, sometimes those people, even with open, with image guidance, they struggle a little bit because in the regular image-guided paradigm, we use the chicken foot or we use the pointer to be able to deflect the tissue, which with the robot, you really can't do because everything is set. So it really depends on how, what the, what particular case you're talking about. But there are, there are challenges, and those challenges are just like there are with open surgery, and they're things that are learned as time goes on. Maybe just one quick question for both of you, for Nick and for Juan. For both of you, as you just look maybe a year or two out in the future, what do you think, Nick, is the next, the next advance for robotics in spine surgery, and then turning it over to Juan after that, what do you think is the next advance in navigation for spine surgery, looking in the very near future? So I think, I think, so I think we will have some sort of augmented bone cutting ability with preset trajectories and depths. I think that will be, will be part of this. And then the secondary thing will be utilizing the image guidance and robotic aspect for an alignment assessment. And part of the end game is how are we doing in surgery, or how are we correcting those patients, especially in the open deformity cases? And I think that goes perfectly married with robotics and with image guidance. So I think we're gonna see a little bit shift in not just doing the navigation, but also getting feedback on alignment, for instance, and how we're able to give ourselves a report card as we walk out of that room with how our reconstruction has gone, rather than waiting for the patient to stand up and realizing we didn't quite hit the mark. Great, great. Juan. Yeah, I echo Nick a lot. I think is definitely we are living in the world of enabling technologies. It's what we're gonna be facing on a spine. And I think small changes in the next five years, which, for example, multiple tasks at the same time, be able to put two pay call screws at the same time navigated or three or four, you know, that can be something that is very close and possible. Integration of multiple technologies, having your head up display where you can see all your screens, you know, fluoroscopy, monitoring all at the same time. All these are short terms, pretty much now technology that we have it. And then also this one is very important that this thing is happening. And I see that Nick is pioneering on this, making the navigation almost real time. Don't forget that we rely on a CT made 15 minutes, two days, three days ago. And if anatomy change, then open the window for a big complication. So, you know, be able to do and actualize real time information to give the feedback and put it back. I think those are short term, easily reachable technologies that it will make more adoption in general. Terrific, terrific. Well, I wanna thank both Dr. Theodore and Dr. Uribe for outstanding discussion on robotics and navigation technology. It looks like, and I think you've made the case very well that this is a firm part of spine care today and a lot of exciting advances in store for us in the very near future. So thank you very much for that discussion. And I think we're right on time. We'll turn it over to Dr. Steinmetz for the next portion of the afternoon. Thanks, that was a great session. So I have the privilege of introducing our four new speakers, one old one with Juan, but the next session is really a technique session to really understand the prolateral, kind of pick it apart and understand how four experts are able to perform such a procedure. So I'm gonna introduce them all at once. We have in our panel, Juan Uribe, Luisa Pimenta, John Polina, and Bill Taylor, all experts, world-renowned surgeons in MIS, lateral and now the prolateral. And so I'm pleased to introduce Juan Uribe to kick it off and give us his presentation on prolateral surgery. Juan. Yeah, thanks very much, Mike. And obviously AANS for big effort, be able to put together in a last minute this amazing meeting. So yes, this block, we're going to talk about prolateral interbody fusion, which is becoming a more popular procedure. And in the next minutes, we will have different speakers and each one showing different aspects of the prolateral interbody fusion. So first question is, who face the benefits of prolateral surgery? I mean, the first question, why are we doing this? And I can tell you right away, there is two big main drivers, which one is the time and money. Money, why? Because the more we save time in the OR, the more we save time for the health system without compromising patient outcomes, the more attractive is the proposition. So that's why we think that the benefits comes more along these lines. So, but when you do it prone lateral versus lateral with the patient on lateral position, you have to understand that is advantages and disadvantages like anything else. So what are the advantages on the prone lateral? First, doing the posterior work, pedicle screw placement, laminectomy, obviously they're right there. The position is very good in terms of orthogonal for the patient. We as a spine surgeons, the natural way to do a spine, we always think it's prone position. Then lordosis is our friend, patient in prone position, the natural way to provide lordosis. And which this one is very important, navigation and robotics is very friendly when we're using the prone position. Why? Because the patient is more stable, less movement, more chances that the navigation work good. And then obviously on the lateral is we have much better ergonomics. It's more natural to approach the spine from the side. We have the patient in lateral position. Is obviously more intuitive approach to get from the side. And this is important. Once you start doing prone lateral surgeries on the lateral position, it's less deeper. And also another possibility is that you're able to do a ellipse on five one on the lateral position, which is very complicated. I'm not sure if someone is doing it an ellipse in prone position. So let's go about the difference between prone lateral and lateral on the lateral position. So this is important because if you start considering doing lateral in the prone position, you have to take away of these three fundamental differences and let's go over each one then. Okay, one is don't forget gravity always is the king. So when you put the patient in prone, all your instruments are going to migrate anterior. Your hands go anterior. So you have to be careful. You're not gonna have more vascular injuries, more misplacement of cages and so forth in the anterior part of the spine. So you have to be aware that you have to correct yourself that things are going to move anterior. And second, the retractor tends to move superficial. So retractor likes to come out. So you need to make sure that retractor always stay deep and well seated on the spine. So you are aware of these two changes that will make a big difference. And then the third one, which is very interesting is what happened to the psoas. This is on a recent study that we performed. So you're seeing here, these three MRIs are MRIs made on voluntary participants on different positions. The one on the left is the patient with the lateral position with the knees flex. The middle one, the patient regular standard supine MRI and the third one, the prone with the knee extended. So you're looking here, believe it or not, the prone position with extended legs, actually the psoas move posterior, which is good because we are thinking that indirectly the lumbar plexus migrate at least the big branches posteriorly with the muscle, which make somehow less interaction with the nerves, potential less nerve complications. And if you compare the prone to the supine, they're very similar. And in the lateral, you see this tendency to move anterior. So conclusion in here is that prone lateral move the muscle a little more posterior, it will make a little more easier your work, but you have to be aware when you're placing your dilator, make sure that your dilators, they don't come this way, which is also a natural way to go lateral. Make sure that you go exactly lateral to that. Okay, so what I'm gonna show you from now on is one of my cases and I walk you step by step and then if you want to go deeper, we published it last year. This is the reference. If you want to get into details is a free access and you can see a step-by-step what I'm doing. One thing interesting with the prone lateral, which I don't have exact explanation why, hopefully Dr. Polina, Taylor and Pimenta can help us to elucidate this or any of you in the audience later on as you do it, why we get in more lordosis when we do the lateral in prone position versus lateral. Because at the end, you put the implant, let's say this case is a 15 degrees implant, but if you're looking here, when you do lateral versus prone that is in the bottom, definitely the gain or lordosis is more. And in the few cases that we have experienced, which is around 30, 40 cases, we've seen a trend to getting more lordosis when doing it in prone, which is very interesting. So let's see the example of the case so we can move. So this is a classic everyday case. This one, everybody that is in the audience have this case, patient with some stenosis and then some spondylolisthesis on deflection extension, grade one, patient has a back and leg pain, fail all the treatment. So in this case, we put the patient in prone. This is a prone lateral case. I want to show you how we do the whole flow. So initially as you see here, we're using a combination of fluoroscopy and navigation. My ideal case scenario is in the future, I can migrate 100% to a navigated technique. So you see here, we're marking the target, which is four, five on the posterior third patient in prone position as you see here. We mark the posterior line, and which is very interesting in here is since we're using a navigation, what are we going to start is first, we want to start with the screws. And the reason is because where you need more critical denavigation is actually during the placement of the pedicle screws, but there is no margin of error. When you go lateral, if your system is few millimeters off, you're okay. But as you know, when you put in the pedicle screws, you have to be in a good position. So what we do is first, initially we put the pedicle screws. And as you see here, we do it in navigation and we keep this fluoroscopy as a sentinel image, make sure that we have once in a while one shot and we have real time information. So the screws are placed in a modular fashion. Notice that they missing the polyaxial heads. And the reason is because we don't want towers on the screen coming along while we're doing the lateral part. So once we put the screws on this fashion that is modular using the navigation system, now we proceed lateral, start dissecting the abdominal muscles. And as you see here, in this case, navigation is very handy. You see here, we guide into the retroperitoneum, the dilator, and as you look in the screen in the middle, we pick what part of the psoas muscle can we go and enter, we verify with fluoroscopy, make sure that the informations are for real. And then we proceed to do the monitoring, make sure that we are in front of the lumbar plexus, and we use commercial directional EMG monitoring. And then once you define and you know that that you are in the front of the plexus, then the next step is confirm the location of your retractor as we see here, using the navigation as well, make sure that your transoas, make sure that you are in a good position. Then follow by start doing what we call the carpentry. So now is the call, make sure that you go through the end plates, and you take your disc as good as you can, as you see here, navigation again, very handly, diminishing the amount of radiation exposure for the patient. And for the surgeon, you see here on the top left screen, the advantage of having a three dimensional view of the spine. And then as you see here, later on, we're doing the box cutters to take most of the disc out, take a look on the video, this top screen where we have this small camera mounted on the retractor, will help us to with the ergonomics of the case, so we can have a more easier access to the anatomy in terms of visualization. So as you see here, you go with your box cutter, you finishing your work on the disc space, you place the case and then which is very interesting, then you capture the polyaxial heads later on, on the screws pass your road. And this is basically your final product. So as you see, prone lateral position is basically similar procedure as the lateral fusion in the lateral position definitely is safe and reproducible. This is very important. So you have to understand that for a procedure to be safe and reproducible, it has to be able to perform in any other modality of, of systems, there is definitely potential for savings in terms of time, because you have access to the posterior spine, laminectomies, you name it. And obviously we need as any other technique is too early need for prospective trials. So always we have opening visiting options that here at the Barrow, if you want to come and spend some time with us and learn this technique and you want to get more ahead, don't hesitate to ask questions. So, Mike, this is what I have to show. We keep going now with Dr. Paulina, I believe so. No, it's with me, Pimentel. Okay, so I'm here. I'm here to talk a little different. My, my, my presentation says QTP is not prolateral and I will try to prove what I'm talking about. So in the last three years, we have been judging what we did, you know, 20 years ago. And after all these 20 years, why only 20% of the surgeons adopt lateral technique? And we came with several reasons that these happen. One is the neurological complications, the lack of lordosis, basically. It's more important is that it's not a familiar position lateral. And the need to flip the patients is also another important point. So in looking to the single position technique in lateral and judging what happens with that, at least on our side, we found that it's not so efficient for pedical screw placement. It's also more limited to short construction and not very, and it's not able to combine more complex posterior procedures like osteotomy. So why we think that is not simply positioning the patient in prone, that is important. We have to make sure as Juan described that we fix the patient in the table correctly. This is one thing. You'll see that we have those positioners and that embrace the patient in the pelvis and in the thoracic and the belly falls down in the Jackson table. And this is a very important, efficient point. The second is that we are able to do simultaneous actions, right, lateral and posterior. For instance, doing lateral while somebody else does the T-lift or place the screws while the PA suture the previous approach. We also think that is more reproducible because as Juan said, we did a study some time ago in Brazil showing that in prone the psoas migrates posteriorly and brings the plexus posterior, so clears about 20% the space, especially important for L4-L5. We also think that is more reproducible because our positioner creates a very strong coronal bending, allowing to achieve L4-L5, clear the pelvis from L4-L5 levels as you can see in this image here. We also study the amount of coronal movement comparing to the chance to do the L4-L5 without this coronal movement is the lower line here. You can see this is the way Juan does. And this is with a coronal bending, the amount of movement that we make with the pelvis, very important. And this is how we do the positioner breaks, basically brings the pelvis down as well as the ribs in case we go to other levels. We have to say that this is still lateral procedure and it still has the same advantage of MIS procedure, short recovery, less blood loss, etc. We also did a study in Brazil comparing the lordosis in lateral and in PTP, and we saw that the PTP lordosis 50% level per level, segmental lordosis, so it's 50% better. It's not only time is money, right Juan? It's better for the patient. So we position the patient in prone and you'll see in this case, for instance, how much open the level, and this facilitates a lot and gets better results. Because alignment is big part of what we do all the time is super important, even in short construction. See this case here, a spongy adjacent level disease that just by the position open about 20 degrees, we have cases that we implanted 20 degree cages without taking the ligament. We will not make probably as many ACRs taking out the ligament. It's a procedure that's nice, but it was implanted because in lateral, we didn't have enough lordosis. That's the reality. Right now, we will probably avoid the ACR techniques. Also, because of the positioner, we can previously align scoliosis cases and allow these make it better and in the near future, we'll have even more capacities to help the deformity world. This is our positioner that is a carbon fiber, and is very low profile and easy to access from under the table and make all these corrections. The second important part of the PTP that again is not simply a prone lateral is the retractor itself. The retractor is lighter, is a single piece, so it's much stiffer. As Juan said, we have to fight gravity and this is probably the best way to fight gravity. We have a two blade retractor that we really make it orthogonal to the spine. We have features to make this happen. We open one blade per time, so we can open first anterior, fix anterior and move the psoas backwards, just the amount necessary for our cage. Just to finish, the last one is a new neural monitoring that has the potential to use SSEPs and we will then monitor the health of the femoral nerve and not relying on the time to make it safer. It's, again, better for the patient. This concludes my presentation. Thank you. Thank you. I just want to get started here. Earlier, you heard Dr. Rebake talk about the idea or the value of operating in the prone position through the psoas muscle and then Dr. Pimenta taking that idea and really over the last several years, evolving it to a very distinct surgical platform and procedure in and of itself called PTP. What I want to do is spend a few minutes here and just show how we can apply these concepts of prone transovasal surgery to common cases that we all encounter in our clinic every day, every week. First is the use of PTP for adjacent segment breakdown. This here is a 72-year-old who had a prior 4-to-1 fusion many years ago with progressive both back and leg pain to the point he was very disabled. Exhaustive non-operative treatment was done. You can see in his preoperative images, he has a PILL mismatch of 32 degrees with a segmental kyphosis at L3-4 of 10. He has a breakdown in regards to degenerative spondy and disc collapse. I'm sure a common clinical entity we all see. I opted to do a PTP on this patient. Some of the advantages talked about earlier is that in the prone position, particularly with PTP in its novel unique patient position, we're able to restore alignment and particularly in the sagittal plane quite effectively to the point where we're able to get significant changes and correction without having to perform more advanced releases or osteotomies. What you see on the left is the pre-op standing x-ray. This is just the patient, what they look like in the patient holder in the prone position with reduction of the spondy, restoration of disc height and correction of the kyphosis. What this allows now is to really correct the alignment and the underlying issue here in a true MIS fashion doing a PTP. What was opted to do is the inner body first. A 20-degree cage was placed in the absence of an ALL release or an ACR and then a limited posterior fixation married into the prior 4-to-1 fusion, a very MIS straightforward approach. None of these correction, it was done with any posterior column work or anterior ALL release. This was all as a result of the patient just being in the prone position in the prone positioner that's unique to PTP. Then you can see here when you compare the pre and post-op images, significant improvement of the segmental kyphosis at 3-4, but also correction of the spinal pelvic mismatch. You can see there was over a 20-degree mismatch, almost a 30-degree mismatch. Then you're able to correct the patient within 10 degrees on the post-op images all through the position without any bony work or an ALL release. Another example, similar cases with spondylolisthesis, and here is a common clinical problem, a 4-5 spondy due to a lysis grade 2. Similarly, you would expect in the prone position that you would get improvement of the listhesis similar to the first case I showed. However, this is an example of a more fixed listhesis where the spondy doesn't really move in the position or in the positioner. What the PTP allows is the variability for the surgeons to change their plan, if you will, on the fly, depending on what we're able to get in the position and in the positioner. What opted to do here was actually do the posterior releases first and place our pedicle screws at L4-5. Using a fixed temporary rod at L5 and reduction towers at L4, we're able to pull the 4 back on 5 and reduce the spondylolisthesis quite nicely, as you can see there. What that allows then is a much easier docking and approach to the disk space in the prone position. Because as was stated earlier, when you start to move things posteriorly in the prone position, the psoas and the plexus moves back with it. That allows for safer docking of the retractor. You can see here, in fact, I opted to dock the retractor more posteriorly because I was getting safe trigger EMGs. With the novel monitoring platform where we can monitor nerve integrity, we're more comfortable leaving the retractor back there. Then the novel retractor in and of itself, being a two-bladed retractor, each blade is allowed to move independently, gives us the variability even in exposing the disk space through the psoas muscle and how we do that by moving either the posterior or anterior blade independent of the other. Once you're able to get everything situated that you're happy with in regards to alignment and exposure, go ahead and place the inner body graft, big biomechanical graft there with the screws in and then just lock down the rod to get a really nice post-op imaging in terms of what we're able to accomplish. Another application we could use a PTP is in deformity. As we stated earlier, the prone position lens itself is very, very lordosing friendly, if you will. In this case, you'll see it is this is a patient, 63-year-old, typical posture of a spine deformity patient prior decompression fusion at 4-5. It failed a long non-operative treatment course. His pre-operative x-rays you can see here with his post-op changes at L4-5, he had normal cob alignment with a PIL mismatch of 36 degrees and an SVA that was positive of 13 centimeters. When I would look at an x-ray like this, I start to worry or wonder how fixed this deformity was and how much bony work and osteotomy I might have to perform in order to get the patient in alignment. Like many, I find pre-op CTMI deformity patients necessary, particularly when I'm looking at doing stuff in a PTP approach. You see you have vacuum changes at 2-3, 3-4, and 5-1. In fact, this is pre-op MRI showing severe stenosis at the upper levels there. As you can see one of the benefits when applying PTP, particularly in deformity, you start to get sort of more lordosing effect in the positioner in the position. And here, we just use this as an example of the pre-op images compared to the intraoperative floral. You start to see those disc space open up, the five ones, that's the fish mouth a little bit, and you start to get this sense that things want to move in alignment. And applying these principles now, you again, you're able to have access to both the posterior and anterior column. And depending on what you want and what you need to accomplish for the patient, you can choose to approach or attack this problem either anteriorly or posteriorly in order to correct it. The other advantages is now you have access to five one. And when I say that you have access in the form of the posterior inner body, access for a TLIF or PLIF, unlike with lateral procedure, which I found very difficult to access five one you're able to access that posteriorly in the more sort of traditional, if you will, posterior inner body approaches. And so what we opted to do here is start anteriorly and here's our intraoperative floral of the two, three, and three, four PTP approach. And there you have restoration of height. You're starting to see more sagittal improvement or sagittal alignment improvement in that approach. And again, these are done without any ALL release or any PSO or any significant bony work. And then what was followed up here is a TLIF at five one and then Smith-Pete osteotomy is at two, three, and three, four, and then fixation done from two to pelvis, just as you see here in the x-ray. You have access again, you have the spine surrounded and you're able to get pelvic fixation, posterior fixation, do bony work or inner body work all in a very efficient workflow manner using the PTP technique. And in fact, this patient, if you look at the post-op radiographs, we were able to get really good spinal pelvic harmony compared to our previous pre-op x-rays, improvement of the global sagittal alignment all through one approach, through the prone PTP operation. Again, being able to access the spine at five one and the pelvis, both anterior and posterior columns as well. And here again, just to reiterate the power of the procedure, you see the pre-op AP and post-op lateral. And just to give you an idea of the level of correction you're able to accomplish with this approach. Thank you. Thank you. Thank you for having me speak today. I think that I'm going last, which is probably an indication that everyone said everything there is to say, but I hope I can at least give you a few tips and ways to avoid complications. Dr. Polina touched on some expanding indications, so we can go over that pretty quickly. These are my disclosures at the bottom. I always remind everybody when we start is that you really need to look at this as a lateral approach. So the standard disclaimers that we all know for the lateral approach, be it abnormal lumbar or transitional levels, six vertebrae, fixed deformities or counting levels or changes in the MRI scan at the level of the four or five, considering that you have vessels which are split or location of the lumbar plexus, all of those things stand, you still need to do this orthogonally. So it doesn't change the fact that you still need to do the good standard things that we did when we were doing the lateral approach. All of that with good patient selection is certainly how you're gonna stay out of trouble from the very beginning. So look at your radiographs, line the patient up orthogonally when you start, look at your MRI scan and make sure you're really talking and you know which level you're working at and where the psoas muscle is, where the plexus is and where the vessels are. As already been mentioned before, positioning the patient with a patient position is very helpful. Remember, if you're using a Jackson table, it's very, very easy to flex the legs and flex the pelvis. When you're in the prone position and you put the person in flexion, you actually decrease the area available at four or five. So you have better in the lateral position with the patient a little bit flexed. When you extend the patient's legs and the patient's pelvis, when you extend them, you actually open up that space at four or five, making the access easier and preventing any complications or any problems from the access. As mentioned, it gives you great access to both back at five one T-LIF and a four or five PTP we're doing here. But I do think if you want to avoid complications and I certainly use navigation and robotics now a hundred percent of the time, I don't have a fluoro in there at all. And you really, if you work at it, you really can get this down. You can avoid your radiation issues. And also you can benefit from the increased and improved screw placement, both with robotics and navigation, which I think make your case faster and easier and is absolutely well done in the prone position. I also think that we sort of look at robotics as a way to access screw placement. And what I really think actually it does a really good job at is pre-planning for your lateral approach. Juan mentioned a second ago, but what you can do is you can mark the incision. You can look for safe access. You can identify the spot on the skin where you're going to start. And you can identify where you want to go. And if you put down a marker beforehand, it's really quite easily. So I use robotics to identify my starting point, to identify my trajectory. I have placed the first dilator with robotics into the disc space and through the psoas muscle, but I find that's probably easier to do freehand with navigation. But I'm a hundred percent navigated with everything now. And the flow of that is really easy. PSI is panoraspinous process array. I've used both the CT navigation and an O-arm and other robotic platforms. And it works very well in all of that. I do think that one of the things that we sort of don't talk about enough is how did we reinvent this procedure? So the idea being is that this is not a simple prone lateral as you heard from Dr. Parmenta. What we have done is to reconsider every step of the procedure because this is a different procedure. And if you're not doing that, you're really not doing your patient any favor. So the first thing that we look at is where should you place the dilator? And I know we have lots of OLLIF fans and we have lots of people that want to go farther posteriorly, as far back posteriorly and open the retractor anterior, which was traditional in another lateral surgery. The reality is, is that either of those, if you do a anterior or an ATP or an OLLIF approach, you have a higher instance of vascular injuries, which can be seen in these studies. And if you do a farther posterior approach where you're going as far as you can posteriorly, you have a higher problem with nerve injuries. So the reality is splitting the difference and going trans psoas is really an ideal opportunity in the prone approach. And that's also an ideal opportunity because the retractor has been redesigned too. So redesigning the retractor to allow you to go mid psoas, opening it up in either direction, and then also attaching it rigidly to the bed. If you want to avoid complications and you're trying to do a prone position, what you will find is one of the biggest risks and one of the biggest problems is the patient moving on the bed and disengaging the retractor from the patient or disengaging the attachments. So the attachment from the retractor, the way it's attached prevents the patient from sliding across the bed and rigidly attaches the retractor to the patient. In addition, you heard a little bit about trying or concerns about moving anteriorly. And that is fixed by not thinking about moving farther posterior, but reinventing and rethinking how the retractor is attached. A light retractor with two blades works very, very well in this situation. The other thing that we really want to do is independently open the blades. So if you are looking for an ALL retractor or you're not independently opening each blade, you're probably opening the retractor further than it needs to be. So the idea being with the two blades and two shims, one in the top and the bottom, you can very, very easily open the retractor only enough to do the surgery. So this is how you prevent nerve or lumbar plexus or femoral nerve injuries. You prevent it by using your trigger DMG to go mid psoas or to go into safe space. You use your navigation to identify that safe space preoperatively, you position the patient appropriately, and then you open your retractor only enough to do the surgery, which holds and keeps from the nerves can be compressed. So that's the one way that we look at it. But the real thing that you really need to do if you're not is really consider SSEPs. SSEPs give you the advantage of real-time information on the femoral nerve. So if you want to prevent nerve injuries, number one, blunt approach, good positioning, lock the patient to the bed, lock the retractor to the bed, lock the retractor to the patient, and only open it enough to do the surgery. Go in the mid psoas or in a safe space and then open into a safe space. Don't be married to opening the retractor anteriorly or posteriorly. You can just go to the safe space. And my feeling is that instead of trading vascular versus nerve problems, mid psoas is a perfect approach. But when the retractor opens up, the only opportunity you have to prevent a nerve injury is really SSEP monitoring. This was a good study done here in which you sort of looked at if the SSEP is normal, there's almost a zero chance of having a femoral nerve injury. And in fact, I'm not aware of a normal SSEP, a saphenous SSEP, and you want to make sure that you have good monitoring and a good way to monitor those patients. I've seen a couple of people where they're sort of peeking underneath and sitting flat. I understand the importance of orthogonality, which is absolutely critical for avoiding complications. But once you have your retractor in, once you're orthogonal, then you can rotate the bed so you're working through the retractor in orthogonality. And that's the importance of attaching the retractor to the patient, attaching the patient to the bed, attaching the retractor firmly so it doesn't migrate, and then rotating the patient once that's all done. And we really can do that both with navigation or C-arm, either one. But work orthogonal, but rotate the bed so you have easy and safe and comfortable working position rather than leaving the bed flat. So that's sort of a quick overview of how do we avoid complications. We sort of looked at some of these cases in which we certainly have people that have a significant kyphotic deformity with prior surgeries, positioning the patient prone, as Dr. Venta said, gains you about six degrees, but we found the real thing that I find which makes your surgery safer and easier is you're no longer relying on indirect or direct decompression. You're no longer relying on hyperlordotic implants. You're no longer relying on an ACR if you need a lot of correction. You simply can do a release in the back, a cage in the front, and you can get a harmonious correction very, very easily. And I think these cases, especially with longer deformity constructs, you're gonna find so much advantage to doing this. This is a pretty typical example of someone that we've done recently. Clearly she had a flat back from a outside institution where they did a three-level ALIF and instrumentation posteriorly. She collapsed over the front, screws migrated into the disc space, got tight stenosis up above, and very, very symptomatic. And so what really the prone position allows you to do is take advantage of gravity, take advantage of the lordosis that's created, do your posterior work quite easily, and do a facet release or any release that you want posteriorly, rather than concerning yourself with hyperlordotic implants or an ACR. Monitor the patient with SSCP monitoring, and then really you rely on position and release and ALL resection if necessary to get your correction. And that's really what makes this important is single position, maintaining your lordosis, and getting a good correction. So I was sort of charged with how to avoid complications, and I think it really starts from really rethinking the entire procedure. So what does the prone position do? It gives us more lordosis, but what it really does is open up that retroperineal space. It opens up the retroperineal space, it moves the psoas and the plexus posteriorly, but that's only if you have a good position and that you extend the legs rather than flex them. Don't simply put the person prone on a standard positioner. And the patient positioner allows you to control that lordosis and in coronal correction, it really anchors the patient to the retractor, and it anchors the retractor to the bed, and the patient gets anchored to the bed, and that prevents the complication of inadvertently removing the retractor and causing problems. And what you really avoid anterior, the way you avoid anterior movement of the retractor is by choosing the correct retractor that locks in place, a single piece, two blades, controlling that, and docking mid psoas. The mid psoas docking keeps you away from the femoral plexus posteriorly, it keeps you away from the vessels anteriorly, and it makes it much easier. So the access has been sort of rethought, retroperineal access. If you look farther posteriorly and sort of feel the quadratus, the retroperineal space opens up. Use your SAF and SSCP monitoring while your retractor's deployed. Only open the retractor enough to do the surgery and use your triggered EMG to gain safe space. I think navigation and robotics are one of the real advantages to this procedure. You can integrate them easily in your operating room, and it makes the procedure much more routine and much, much safer for the patient. So the conclusions really work simultaneously, and you can speed this procedure, but no repositioning, so time is a factor, and it really, the patient's under anesthesia for less time. It's really a single position. Lordosis improves the nerves and the psoas muscle move posteriorly. But what really this does is it makes your decision-making simpler. You no longer have to think about indirect decompression or cage size or other things. What you can do is simply do what you would normally do and take advantage of the lateral procedure with its large cage, high fusion rates, good lordosis, and good indirect decompression, and also use navigation and robotics for that. So in summary, this is not just the prone. Don't think about using the same equipment. Think about how you're gonna position, how you're gonna lock the retractor, extend the legs, saphenous nerve monitoring, and think about how you're gonna traverse the retroperitoneal space and then where you're gonna dock, which can be done robotically or it can be done with triggered EMG or both preferably, and then monitor the patient while you're doing it and simplify your procedure, no longer relying on things that you're concerned about, which would be lateral plates, multilevel procedures. All of those become very, very easy. And I think you'll have an excellent result of sort of rethinking the prone position for the lateral surgery as a new procedure with new equipment and making an excellent result. Thank you. Well, it gives me a great pleasure to be able to introduce Reg Haid as the next speaker. Reg is obviously the WNS president, but also a former spine section chair. And he's here for the Sontag lecture, and he's gonna talk to us about what Volker taught us. And to me, this is truly amazing. This is like a master commenting on a greater master's or more senior master's teachings. It's kind of like hearing Luke Skywalker talk about what Yoda taught him. So Reg, we are very much looking forward to this talk. I'm sorry that we're not in person in Orlando, but hopefully we can reach an even bigger audience and be more impactful this way. Well, Mike, thanks so much. Volker, I think he just called us both old. So it's a real honor to give this talk. And Volker, I wish you and I were here in person and having a Manhattan afterwards. So several years ago, I got the Meritorious Award for the spine section. I listed four men who were my mentors, the last of which is my dad. The third was Volker. And I said that Volker taught us to innovate and taught us integrity. So really this whole thing is what would Volker do? And it comes down to the two I's, right? It comes down to innovates and it comes down to personal integrity. Nick Theodore, who was a resident, which when I remember him, talked about how Volker was a early adopter. And I think Volker and Robert, the B and I at those times, really, really pushed it. So I do what old guys do, right? I talk about the past and I talk about lessons learned. And this is what this is about. So to all the young guys out there, everybody's in a rush, right? Our careers are journey, it's a process, it's an evolution. If you were in the Southern hemisphere, it would be a walkabout. And I know Volker trained with Ben Stein at Tufts. He did pineal region tumors. Neither he nor I plan on becoming spine surgeons. When I told my chairman, I was gonna do an orthopedic spine fellowship, he told me I was, quote, wasting my career, that I was not a bad cerebrovascular surgeon. So what I wanna share with you now is to have an initial plan in mind, but be open to travel and open yourself to serendipity and to end up in a different place from where you started. So as an analogy, I'm gonna show paintings. It's from the same painter. And I'm gonna ask you to guess who this painter is. When I first showed this, somebody said Rembrandt. It's not Rembrandt. But I'm gonna show you the evolution of a painter who was open to transform things. So my personal journey, I was an old-fashioned neurosurgeon. We clipped aneurysms, there was an endovascular. I spent time with Al Roden and Shaker and Samuel Mephi and Chandra Sen. So I did a lot of skull-based tumors. Like all of us, we did nucleomas. In my training, we did stereotactic cryoablation for Parkinson's and tremors with thalamotomies. I did ripples or perks. And then 1994, when I was at Emory, I switched over. I just couldn't do everything well. And that's when I went to spine. And that was my personal choice to focus and subspecialize, which at that time wasn't done a lot. So what I wanna do is think about the contradistinction between my career and the first session of the day where we're talking about robotics and prone trans-SOAs and how far that we've come in just my career. So when I was a resident, we did posterior cervical LAMs and lumbar LAMs. We did anterior cervical discectomies, no fusion, no plating. That was an orthopedic procedure to fuse. We did corpectomies for tumor where we would put in Steinman pins and polymethylmethacrylate. Again, when you went to the spine section, all you heard about was Chiari's and tumors. Posterior cervical fusions was wiring at the time, 18 gauge wire. In 86, I worked with Joe Maroon and Gary Onig doing percutaneous discectomies. We put a ton of halo braces on and I had to go work with the orthopedist to learn how to harvest an iliac crest graft. Again, when I was a chief resident, there were no lumbar pedicle screws, no thoracic pedicle screws, zero 3D correction. I scrubbed in with the orthopedist to do Harrington and Lucas. There were no A-lifts, X-lifts, T-lifts. We did a few plifts, but again, that's with autograft iliac crest and no screws, zero scoliosis. And if you wanted to go to the crest or the ilium, you had to use a Galveston technique, which was not that good. Again, same artist, who's this? Same guy. So my fellowship was really an interesting time. I went and I was a staff with Al Roden where I learned skull base and drilled out temporal bones. I was an orthopedic fellow. And then at that time, I went to Bethesda, Maryland, where we had Volker, Ron Applebaum, Paul Cooper, myself, Kevin Foley would stop in, Dave Pauly, former SRS president would stop in. And we'd literally taught ourselves. We taught ourselves. So when I went to the first Barrow Symposium, Volker, November of 88, Ian Kalpas was your fellow. I think Steve Papadopoulos was interviewing or something. Applebaum had just published his 14 anterior cervical plates with the Caspar system. One of the participants asked about the new CD clotrile duplication instrumentation. And your orthopedic faculty said, no, that's just hogwash. Harrington rods are fine. And being young and stupid, opened my mouth. And I said, no, no, no. I use CD instrumentation for 3D correction. And I was not so blatantly told by your orthopedic colleague, little boy, go home. You don't know what you're talking about. So I went to visit Arnold Menezes in December to learn trans-orals. We started doing corpectomies for DGEN, tumor and trauma. I learned from George Seifert how to do allografts. So during my fellowship year, Volker, we had a doubling ass course and you taught people how to take 21 gauge wire and twist it. That was our hands-on. And I helped George teach how to take a piece of allograft bone and notch it like Tom Whitecloud did to do corpectomies and put people in a halo. October of that year, Paul Cooper came down from NYU, bought a bunch of Roy Kimme plates. We could not get them. So we designed them ourselves. It's called Hay Plates. I put them in the mail, sent them to Volker and Volker and Ian Kalpas did some posterolateral mass plates and got in trouble from the orthopedist. Volker then and I, we met Matt Songer who talked about Songer cables. And that was like, oh my goodness, this is really something. I went to Larson's lab and learned the lateral approach and Volker, you came and other people and I taught you guys pedicle screws. And I remember certain very famous neurosurgeons said they wouldn't let me teach them because I wasn't board certified teaching them pedicle screws. So then what did I learn? Well, I learned lumbar pedicle screws at that time with the CD instrumentation. We did posterior fusion techniques with onlay fusion. There were no thoracic screws then. We did hooks and rods with universal instrumentation. We started doing thoracotomies. I did my own lumbar retinal approaches. We used allograft tibia or femur for our corpectomies. And I went to the Letterman Spine Center where Kaneda was there showing his interior device. Same artist. Hopefully you guys are starting and gals are starting to realize who this person is. So all of our innovations that Volker and I started working on, we're all team-based, right? We all had surgeons and engineers. We did a market analysis, financial analysis, but again, we were lucky. We caught the right wave at the right time. So when young people ask me about innovation, don't just innovate to innovate. There has to be a real need with a volume. There has to be a market who will accept it and buy it. It's gotta cost, be reasonable, valuable. And you have to have resources. You have to have financial resources, know-how, time, materials. Case in point, I did not have my resources with my first pad with Mike McMillan. So we actually thought about taking out a vertebral body and we would put in tibia or femur and just lock it in place, turn them over and put in pedicle screws in the back. We called it a box-in-one for L2 and three burst fractures with retropulsion. So we designed this device. You would put an urgency in place, turn a turnbuckle. It would expand. Well, University of Florida, and we shared this patent, Mike and I had no knowledge about how to get this to market and that patent languished. So again, you have to understand how to do this. So after my fellowship, again, I went out to Bethesda with Peter Claire's course with Volcker. And again, we had Andreas Weidner come over, Dieter Grob come over from Germany and Switzerland. And we learned from our European colleagues. And again, Volcker's Prussian and I'm Bavarian. So I think there was a kindred spirit because we would drink beer afterwards. We learned about anterodontoid screws and transarticular screws. And we learned from Wolf Caspar himself, how to plate. And Caspar showed us how to do a plate at C2,3 for Hayman's fracture. We thought he was crazy. He was so far ahead of his time. And again, so I taught people some posterior cervical plates. We didn't have rods back then. For the rest of this stuff, we just kind of did it. You know, there weren't courses. There really weren't textbooks. We just, I had a fellow, Barry Birch. We put in C1 lateral mass and pedicle screws and got the original stealth. The Papadopoulos was working on an Ian Kalpas and we put in pedicle screws all the way down. We had to design some spacers for Smith-Robinson that were tantalum. That didn't work well. So we converted that to allograft and now to peak. Volcker designed a thing called the bendmeister which he still calls the Meisterbender where we could take a Steinman pin or a rod and actually bend it or we could cable into the occipital things. I started working with Chet Sutterlin where we designed some occipital plates. So we would put screws in with the axis plates. And again, people saw this and screws in the occipital and thought that we were absolutely crazy. And we were called young Turks. At that time, Steve Papadopoulos, Kevin Foley and Ian Kalpas were working with navigation which was a total pain in the keister back then. Kevin and Mo came out with tubular posterior decompression and we started working on the arthroplasty designs in the late 1980s and had the first two out of three arthroplasties. After fellowship again, we just started doing thoracic pedicle screws. We just kind of did it. Curtis Dickman and others started teaching us the work of stopping things with the industry labs in Cincinnati. Osteotomies, I learned from Dave Pauly and Ogilvy and Chris Shaffrey and all of our orthopedic colleagues. And again, Volker would teach courses about how much of the rib to take out, how to drill down the pedicle. He and Robert, how to bend the patient. This was cutting edge at the time. Again, this stuff wasn't invented yet and Volker helped to invent it, right? So we started inventing A-lifts which came out of our laparoscopic labs. Once we figured out laparoscopic demand in a surgeon, we just converted that to a small mini open approach. Cages came around for plips. Shaffrey and I and Kalpas visited Harms to do T-lifts. I went out to San Diego and learned from Juan how to do an X-lift. And I find it very interesting now that Volker is next to Juan in their office watching this. And I think about Volker, how much spine surgery has changed in our careers. It's absolutely mind boggling. Surgeons didn't do deformities. Now we do deformities all the time. We didn't do osteotomies. The navigation, the robotics, it's just endless what's happening. So what Volker has always done is he's defined the need. He's defined his assets. He's gathered all of his assets and formed a great team. He and Robert have always been great at forming teams and they just did it, right? You just go do something. You don't talk about it, you just do it. And you build it on what you know how to do. Pablo Picasso said, I steal from everybody. I steal from everybody too, as does Volker. You take every good idea out there from surgeons, from orthopedists, from ENTs, from industry, from biospace engineers, from hip and knee surgeons, and you integrate all this information together. So the first thing I did in 88 was a lateral mass plate. Now, almost all the innovations are iterative change. There are very few things that are just instantaneously transformative. So we steal ideas from multiple sources and we go outside the box to learn, okay? So the things that are in yellow are the things that I had the honor to work with Volker on. With the Codman plates are the first J&J spinal implants. With Medtronic, we've done a bunch of plates that's still in use. Alex DeCaro and I worked on the absorbable plate, which didn't work out so well. And Kevin Foley and I worked on an artificial ligament, which still sits on the shelf. And I still think it's a great idea. Our spacers, again, we started with tantalum. It was too thick. And so Brad Coats, the engineer, said, why don't we just mill allograft bone? Well, what's happened from then? We go to peat, we go to porous peat, we go to titanium, we go 3D printed titanium, on and on and on and on, iterative change. Chris Schaffrey, Linky, Jim Schwender and I worked on some Crescent and Boomerang T-Lift devices. I helped design the first expandable device, T-Lift, which again, expandable devices now are just everywhere. They can go up, around, sideways. They can realign concavities and chronal things. Again, the materials keep happening and the less invasiveness keeps happening. Again, we started off with hooks and rods and straight distraction compression rods. We're so advanced now. We can go up and down the spine. We can navigate, we can computer plan, we can realign, we can create apps that we use on our phone to assess people in the operating room, pre-op and post-op to see if we accomplished our goals of alignment, which when Volker and I started, we didn't even understand at all. Again, who's the artist? This starts to become a little more famous now. So why is this important? Okay, here's the message today. Almost every implant and every technique I did not learn in my residency. The foundation was in my residency. How to think was in my residency and fellowships. And it continued to evolve over week-long courses, AANS, SRS, industry courses. I would go visit people, okay? And you just go visit an expert and you pick up a pearl at a time. And so much, it was colleagues training each other. I can remember the lab at Bethesda, Volker and I talking about, how do you figure out what links screw in a cast bar? How do you go bicortical? Well, by now, if you can't figure this artist out with starting around this blue period, et cetera, that's kind of sad. I need to go away and spend less time in neurosurgery. So how do we expand to this? How do we get to Chris Schaffrin, the past president of AANS, the president of the SRS? How did we go from Volker's time where he was told by his orthopedic colleagues he could not put metal in the spine? And Volker was the man, okay? Volker was the man that changed spine surgery. And that is not an exaggeration. And then we have Juan. It's kind of interesting, Volker's English and Juan's English are both kind of broken. There must be something about being in Phoenix and having broken English, but this is Juan's case here and this is Juan's case. So if you look at Volker at what you and I did, and now look at what Juan does as the Volker Sontag chair at the Barrow, it's light years. So you can't just ask customers what they want and give it to them. That's Steve Jobs, right? By the time that they figured out, they've already built it. So one of my favorite things is to ask the naive question. There's a consultant out of McKendrick, Peter Drucker, and Drucker said, ask the naive question in business. If we weren't doing something the way we are now, how would we do it? If we're not doing something the way we are now, how would we do it? So during my fellowship, I told Dr. McMillan, the orthopedist, we'll be doing a fusion without harvesting the crest. And Mike told me, think out of the box. I remember very clearly telling Mike, Mike, there is no box, period, right? So don't think out of the box to all the young people out there. There is no box. So what's the think out of the box come from? So I would ask Theodore to do this, but he's already figured it out. Never lifting the pencil from the page, connect these dots with four straight continuous lines. In the sake of time, we're all spine surgeons. It would take us a long time. Here's one answer. Here's another answer. There's not one answer. So out of the box is a metaphor, right? It's lateral thinking. It's creative thinking that rejects the accepted paradigms. And this is credited to John Adair, an academic leadership theorist. And I look at it as the judgment of Solomon about the baby. Completely different way to think about things. So Clay Christensen, who Bill Caldwell had as a speaker at the AANS, he just passed in the past couple of years. He's been called the most influential business person with ideas of the 21st century. And he's a guy that coined disrupted innovation, right? Everybody talks about disruption now, but this was 25 years ago. And he's talked about innovation that creates a new market and disrupts and is transformative. So if you think about neurosurgery in our world, think about the adoption of new ideas. I remember Robert Spetzler and Nick Hopkins arguing about coiling. I was told that I was raping the spine because of pedicle screws. Picasso, who's the artist, was told he didn't know what he was doing. When Al Roten used to teach people the operating microscope, they thought it was unnecessary. I went to visit Dave Lunsford in 87 when he just got back from the Carolinsta with the first gamma knife. Elvis came on the Yes I'll Live and Show and they wouldn't show him from the waist down. So why do some innovations become adopted? I remember showing lateral mass plates in 1889. I was told that's just stupid. Neurosurgeons would never do that and they would never drill and never tap. Why is it you go to a neurosurgery convention and there's blue blazers? How do religions catch on? What about democracy? This morning we talked about robotic surgery, lips for seizures, CRISPR therapy. Well, no matter what it is, if there's a promulgation of new ideas, it's hard, right? Whether it's Islam, Christianity, instrumentation, Volcker can tell you it's been hard. Jeffersonian democracy, hard. Kevin and Rick Fessler took big hits because of MIS. So no matter what our personal stance is, we have to have ambiguity of thought, which our country's lost. We have to be able to hold two competing ideas in our head at the same time and think about it's not polar, it's not black or white, it's gray. And the last thing I want to leave you with is there's two concepts of cultural advancement. This is within the neurosurgical field and with all the history of mankind. The first is there's a multi-generational advancement from Volcker to me, to Praveen Momineni and Mike Kaiser, my fellows, to their fellows and their fellows' fellows. And the last is what Volcker's talked about with Spetz is disruptive technology, right? And so everything that we do has multi-generational advancement and it's interrupted by disruptional technology. And this occurs in neurosurgery, in spine surgery, in art and music. It occurs in physics from Newton to Maxwell to Einstein to Hawkins. Thierry Desjardins was a French scientist priest. One of my favorite quotes, and I studied him in college, is we work together by standing on the shoulders of previous generations. In Volcker, I stood up on yours and people stand up on mine. And that's why when we look at this format today, it's exciting to see what these young people are accomplishing. But this happens everywhere, right? It happens with Frank Lloyd Wright, Gary. It happens in music, art. It happens in warfare, unfortunately. It happens in math, physics, and neurosurgery. Because if we take time to set back and not be so self-absorbed, but be outward thinking, nothing that is great is ever achieved in one human being's lifetime. If we think about our neurosurgical lifetime, from Cushing to Danny to Drake to Yossergill to Rodin to Spetz to Hopkins to Volcker, right? Think about over the generation of neurosurgery, what's happened and how we take such good care of people. And this is in spine surgery, it's in functional neurosurgery, it's in everything. So it's always disruptive thought by individuals. It's multi-generational. It's adopted by a society or a specialty. And this is even in Western thought, right? Whether it's Socrates or Marcus Aurelius. I was a philosophy major, so political philosophy was Hobbes, Rousseau, Locke, Jefferson. Again, it's individuals that have deflection points that are disruptive, but there's iterative changes over culture, which is what spine surgery's done. Music's the same way, right? Elvis and Chuck Berry were disruptive. I remember I loved Clapton and told him it was drug music. My son years ago talked about Lady Gaga. I thought she was a freak because I failed to understand her talent. So disruptive technology is not always easily accepted. Why are some ideas advanced? Why do some ideas make it? What drives us to innovate? How does this relate to patient care? Well, obviously by now you figured out that it was Pablo Picasso from the self-portrait. And if you look at that guy, how disruptive he was, how he started off as a draftsman and went to create the cubist and the actual essence of what something is in his lifetime. He did not stand still. So Picasso had disruption of thought and that thought diffused throughout his lifetime. And I'd like to put to you then that patients are some of the principal drivers, right? Patients want less pain, smaller incisions, outpatient, low complications. They want to get back and play and work faster. So though we want that, we are continuously pushed, but that's that push and pull, right? Sometimes the best thing for our patients is not the MIS. Sometimes it's the big Chris Chaffrey, big dog daddy deformity. So that's up to us as gatekeepers to figure out how much to listen to our patients and how much to tell our patients. And Volker and I have talked about that over the years. So the ultimate use of technology is unknown. Might be the thing about robotics today, the thing about prone trans-so-acidic. You know, it's not opinion, it's outcome analysis, it's cost analysis, it's resource allocation. And how do we measure outcome and cost? There were several papers this morning from the QOD that I was part of that I'm very proud to be part of looking at the value and the science of our outcomes, not Reg's opinion, but what does the data say? Because we have to show value where technology will not get paid for. Lewis Carroll was kind of a crazy guy, but he was very creative and very imaginative. And Alice in through the looking glass told the queen of hearts, it's no use. One cannot believe in impossible things. And the queen had a good answer. And she said to Alice, I dare say you haven't had much practice. When I was your age, I spent at least a half an hour a day imagining impossible things. So my last slide, this is Mandela when he was preventing the bloodbath in South Africa and he united the country with the World Cup Rugby Championship. And at some point we have to dream, we have to advance, we have to create, we have to assume risk, we have to be disruptive because remember, I stood on Volker's shoulders, now you young people are standing on mine. Volker, it's an honor. Thank you so much. Hi, Reg, that was a phenomenal speech, talk, not only giving us the history of spine, the neurosurgical history of spine, but also correlating to arts, to the music, to philosophy, and how this all evolved us that we're not only have a tunnel vision such as only spine, but we have to look at the whole picture, just as we treat patients, that we have to treat the whole patient and not focus on one patient at a time. And not focus on one particular thing and think of their thoughts and their pain and discomfort, and also think of the family. Reg, I really wanna thank you for a terrific talk, giving us all insights on your thinking about spine, and of course, your tremendous contribution to the field of spine and neurosurgery. Thank you again, and hope to see you soon. Thank you. Reg and Volker, that was really, really terrific. A real privilege to listen to that talk and inspirational words about the history of spine. We have a few minutes break, about 20 minutes break, and we'll be back to continue more great spine talks and education at 4 p.m. Eastern time. So we'll see you in just a few minutes. Thank you. Well, hello, everybody. Welcome back from the break. It's been a fantastic session so far, and I think we'll just continue that into the early evening here. It is my pleasure to introduce Dr. Catherine Miller, who's gonna talk about something that's incredibly important to all of us as spine surgeons, which is sort of that optimization of the patient with medical comorbidities such as osteoporosis. She's gonna give us a presentation on optimizing those patients with osteoporosis. Catherine. Thank you, Dr. Simons. I'd like to thank everyone for letting me give this talk to you today. So I'm gonna talk about osteoporosis, which is a topic that we are all familiar with, but I don't think many of us as neurosurgeons feel like we're experts in the field. I do think it is important for us to know how to optimize these patients to decrease the risk that is commonly seen in this patient population. I have no disclosures. So as we all know, osteoporosis is characterized by decreased bone mass, and this comes from a result of impaired osteoblasts and osteoclasts, a decreased functioning of the bone marrow with poor vascularity, which ultimately results in a change in the microarchitecture of the bone. There are two types of osteoporosis. The first is primary osteoporosis, which is broken further down into postmenopausal, which obviously affects women, and then senile, which can affect both men and women, but is most common in women. Secondary osteoporosis is a consequence of an underlying medical condition, such as renal disease, vitamin D deficiency, hyperparathyroidism, and can also be associated with multiple medications. In the next five years, it's estimated that the world population is going to rise above 8 billion people, and at least 10% of those people are gonna be above the age of 65. And why these numbers are important to us is because osteoporosis is proportional to the aging population. So the significant social and economic burden that's associated with osteoporosis will also continue to rise as the population ages. We see a similar trend in the U.S. government data looking at people over the age of 65. This number is also expected to increase to over 70 million people by the year 2025, which will represent about 20% of our U.S. population. This is a chart from the CDC showing the correlation between age and the prevalence of osteoporosis. It's broken down into men and women, and you can see for each decade, there is increase in both osteopenia, which is represented by the green bars, as well as osteoporosis represented by the blue bars. And we look at total numbers. This is a slightly old slide, it's about seven years old, but the numbers expected by 2030 for osteoporosis and osteopenia range over 70 million. So this is something that we are gonna continue to see as our population ages, and these people do need spine surgery. I think another big piece of the puzzle is the economic burden that comes with osteoporosis. A recent study looked at the estimated costs for just the direct medical costs of osteoporosis and said it would be about $80 billion by 2040. When you factor in the indirect costs, such as lost wages, loss of productivity, as well as caregiving needed for these patients, it can range almost up to $100 billion. The scary part about these numbers is this is just estimates for fracture costs and the related morbidity to it. It has nothing to do with spine surgery or the adverse effects that we see with these patients. And again, many of us are saying, why is this important to us, we're surgeons, but several papers have retrospectively looked back at patients undergoing spine surgery, and one report stated that about 20% of people undergoing spine surgery had osteoporosis. When they narrowed that search down to the geriatric population, they found about 70% either had osteopenia or osteoporosis. And I know from the people that I'm seeing in my clinic, they're significantly elderly, and many of these people do have severe stenosis or other pathologies that have to be treated. And here's just a list of some of the commonly treated spinal diseases in the elderly, and some of them do require surgical fusion, which obviously is gonna be affected by osteoporosis. So that that is the challenge for us as spine surgeons. When we think about the biomechanical considerations related to a surgical fixation, either it's pedicles through pull-up strength, insertional, a twerk, or fatigue failure, all of these are directly affected by bone mineral density. So in patients with impaired mineralization, compromised healing, or poor activation of their stem cells, they are at a higher risk of having some of these adverse effects that I've listed here, either pseudoarthrosis, proximal juncture failure. They can also have fractures in the pedicles or compression fractures. And here are just some pictures that I got off the web. And as we can imagine, images like this lead to worsening pain, can have neurologic deficits related to them, spinal malalignment, trouble walking, and ultimately require revision surgeries, which also increases the cost in care for these patients. And as I mentioned, I don't feel any of us as neurosurgeons think that we are experts in the field. So I did look to the experts of endocrinology to give us their recommendations. I found a recent publication of the guidelines for both treatment and diagnosis of osteoporosis. This came out in May of 2020. It's a very robust, it's about 50 pages. They have all the data and literature that they looked at. And while it is very general, it does not have any specific spying recommendation. So we have to take that with a grain of salt, but I will try to marry their guidelines with what literature we do have related to osteoporosis infusion and try to give us the best recommendations possible. There is just to know a second clinical guideline out by the American College of Physicians. This is just a few page guideline. It's not as robust as endocrinology. So I really just revert back to the endocrinology guidelines for kind of where I'm getting my information from. So in order for us to optimize a patient for surgery, we have to investigate whether or not they have osteoporosis. And again, why this is important to us is I think it in many folds can affect how we make our decisions. When we're thinking about what we're going to do for a surgery, whether or not to instrument a patient may be affected by their bone density. When you think about what levels you want to instrument, you might include additional levels if you're worried about poor fixation. If you're doing a deformity correction, you may reconsider where you want to get your correction from or how you would get that correction or accept a lesser degree of correction just based on the high risks if they do have osteoporosis. Timing of surgery can also be affected. You may decide to delay a surgery if it's not emergent to start treatment of osteoporosis, which can improve outcomes. I think a big portion of this is patient education. Knowing whether or not someone has osteoporosis gives us realistic expectations of what they possibly could have in the postoperative period as well as what risks that they are at a higher level for given their poor bone marrow density. And then there's also intraoperative techniques, things that we can do, and I'll touch upon a little bit later, to try to decrease some of these risks. So the DEXA scan is the thing that is recommended for determining what a patient's bone marrow density is. Again, this is a table coming from the National Osteoporosis Foundation that recommends who should have a DEXA scan. It usually is women over the age of 65, men older than 70, but you could investigate patients that are younger if they have a higher risk profile or if there's any patient that has a fragility fracture. And again, this is not something that we use a common preoperative workup like we do for a chest X-ray or EKG, things that we normally do for our preoperative workup, but this should be something that we consider, especially if we're worried about a patient and their postoperative expectations. So the results of the DEXA scan gives us a T-score. The T-score is the standard deviation between the bone density of our patient and that of the bone density of a young, healthy 30-year-old woman. Normal is considered negative one and above. Osteopenia is negative one to negative 2.5, and then anything below negative 2.5 is considered osteoporosis. There are many papers out looking at other things that we can do to investigate the bone density without getting a DEXA scan. These are two papers that have been out for a while now, but they looked at a CT scan and looked at the Hounsfield units and compared that to the bone density. And they did find a significant correlation between the Hounsfield units, the bone density, as well as the T-score. And so many of us are already obtaining a CT scan as part of our preoperative planning. So it's a possibility that we'd be able to use this imaging along with or in a different way compared to the DEXA. This is another way people are using the preoperative CT scans to look at possible risk of a future fracture. So this is the paper that looked at patients who underwent fusion. When they went back and looked at their preoperative scan, they found that the Hounsfield units of those who had a fracture above the level of fusion was much lower than those who did not. So this is something that can help educate us and our patients just to give them a complete risk profile. And it might actually affect if we decide to add additional levels to our fusion. Another tool that we have is online. It's developed by the World Health Organization. It's called the FRAX tool, Fracture Risk Assessment tool. This is an online profile that you can fill out for each one of your patients. And what it does is it gives us the 10-year risk of a possible hip fracture or a total osteoporotic fracture. So here's the questionnaire. I've just filled it out for this is a standard patient that I would normally see in my clinic. They look at height, weight, if they've had a prior fracture, if they are a smoker, they use steroids, they have rheumatoid arthritis, if they drink a significant amount. And then there's also a place where you can include the T-score if they've already had their DEXA scan done. And right here in the red box is what we ultimately are looking at. Again, this is a 10-year probability of a hip fracture for this patient would be 6.7. And then for a major osteoporotic fracture would be 21. And it said that anyone that has a hip fracture greater than 3% or a major osteoporotic fracture greater than 20, those are the people that should be started on treatment regardless of what their T-score is. So even if they're osteopenic or they have a normal bone density, they should be started on treatment. So this is a table that I pulled from the endocrinology guidelines, who should be started on treatment. Again, obvious is if someone has osteoporosis or a T-score less than negative 2.5. For the osteopenic patients, if they do have a known fracture already, or if they have that high frac score, so they have those higher risks in the next 10 years, those people should be started on treatment. And then also patients that have a spine or hip fracture with little or no trauma, those people regardless of their bone density should be started on treatment. Other things that we should be looking at, and if you've already filled out the FRAX form, you would have already asked these, but if someone has alcohol or tobacco use, how much they exercise, steroid use, all of these things can affect bone density. And then there's several other labs and other things that we can do to rule out secondary osteoporosis. This is a chart that I pulled from the guidelines, and I don't know if any of us as spine surgeons are interested in ruling out all of these possible causes for secondary osteoporosis. I think it's more pertinent that if we are worried or if we get a DEXA scan and it does show osteopenia or osteoporosis, that we refer our patients either back to their primary care provider or their endocrinologist so they can complete this workup because there's a lot of things that need to be ruled out in order to ensure that it's primary rather than secondary osteoporosis. And then here also are the tests that they recommended. So there's a significant amount. So I think, again, this is probably better in the hands of a primary care provider or endocrinologist to complete this workup and make sure nothing's being missed. So if you're waiting for your patient to undergo workup for possible osteoporosis, or they just recently got a diagnosis, there are some non-medical optimization things that we can do for our patients. And so you can encourage them to have a nutrition diet, make sure they're getting adequate calcium and vitamin D. If they have known vitamin D deficiency, treat this appropriately. Ensure that they have regular exercise, make sure they do not fall, which is a big thing where I live with our elderly population. And then encourage them to stop smoking and stop excessive alcohol. Again, that is a big issue where I live. But these are just general recommendations that you can make to any of your patients. And I've really started even younger patients who I'm not as worried about osteoporosis. We kind of go through these, I call them bone health recommendations, just things that they can work on because really people say that prevention is the most important principle when you're trying to manage osteoporosis is just even preventing it from happening. So onto medical treatments. Again, the goal of these treatments are to improve the bone biology, help the healing response, as well as if possible, increase the bone density in our patients. And so again, this is just briefly who should be treated with the DEXA score as well as a FRAC score if you've completed those. Also just getting a history if someone's had a fracture with little or no trauma. Again, you might not have the DEXA or the FRAC score, but those people should be started on treatment. This is just a table from a recent publication. Again, it's quite small. I don't expect anyone to read it, but this just shows the many different options that are available to treat osteoporosis. And again, while we might not be the ones prescribing the medication, I do think it's important for us as surgeons just to know what options are available, their mechanism of action, and then if any of them have been studied in terms of what their effects would be on a spinal fusion. Knowing some of this might help if we are doing a referral back to the PCP or the endocrinologist that we could request that they do not start medication X if it's been shown to have an adverse effect in terms of fusion. I think kind of the low hanging fruit here is preoperative vitamin D deficiency. This is something that's actually quite prevalent that I was surprised about. Here are several papers that looked at patients undergoing spine surgery and the preoperative vitamin D status. And there's actually a significant amount of patients who have surgery whose vitamin D level is quite low into the deficient scale. So they range anywhere from 25 to 74% of patients had vitamin D deficiency. And it has been shown to be an independent predictor of prolonged time diffusion, as well as pseudarthrosis. This is another study that was a systematic review of five different papers looking at vitamin D deficiency and outcomes. And what they found from this is that people with vitamin D deficiency undergoing surgery did have higher non-union rates, took longer for them to fuse, as well as had worsening outcomes. When they supplemented these people though, their outcomes did improve and they did have an improved fusion rate. So vitamin supplementation, I think is fairly accessible. It's relatively inexpensive. The majority of vitamin supplements don't actually need a prescription. So again, this is something that kind of good bone health that I recommend to all my patients, regardless if I'm worried about osteoporosis or not. But here are the doses and again, some of it depends on whether they have just normal vitamin D level or if they're insufficient or deficient. And you should also supplement this with calcium as well. Moving on to other pharmacologic treatment, they're usually broken down by their mechanism of action. You have your anti-resorptive versus your anabolic medication. And again, this is just a list, not for anyone to read and memorize, but just more to see that there are several options available for treatment. Again, some of it varies from dosing to timing and scheduling. And there's some that you're taking daily and there's some that's an injection just once a year. So again, all of this plays into what you would prescribe for a patient. And again, some of this is out of our realm and kind of falls back into endocrinology for when they would choose what medication. But here's briefly their flow sheet for patients that are at high risk for osteoporosis. And what they do recommend for a first line is the bisphosphonates or denosumab, which is polio. They go on further. And again, I don't expect everyone to read this, but they talk about how long you should have patients on these medications, what you should do for a drug holiday and other things to consider for each of these medications. A second flow sheet they have in their guidelines are for patients that are at very high risk or people that have had prior fractures. So instead of recommending the bisphosphonates, their first line for these higher risk patients are the anabolic. So the teriparatide, the valoparatide. Prolia is also included in here. And then this is also for patients that if they cannot take oral medication, so some of these are injectable. So we'll start off by going through the bisphosphonates. Again, this is the oldest and the broadest class of drugs, the one where the majority of the literature has been done. The goal of these is to disrupt osteoclastic borne resorption. It induces osteoclast apoptosis. There are several drugs that I've listed here. And as with any drug, there are some complications, but I won't go through all of those. I think the biggest controversy with bisphosphonates is there has been some prior, both animal and clinical studies that have shown some evidence that it may inhibit fusion or there might be some inhibitory effect on the osteointegration around implants. However, there's no clear consensus that have been all of the literature that's been published. I think a thing that I picked up while doing this talk and which I did not know is that if you are worried about bisphosphonates and someone's been on them and you want to stop them before surgery, this medication actually is slowly released from the bony surfaces. So it's not like if you stop it, it will be gone out of your system in time for surgery. The medication can be around for months to even years, the bioactivity. So again, that's just something to consider looking forward for surgery for one of your patients. There are several papers written about bisphosphonates. This is one of the randomized control trials looking at cylindric acid versus saline. They looked at fusion out rates as well as vertebral compression fractures. And what they found is that the fusion rate at three, six and nine months was higher in the study group compared to the control, but there was no difference overall at their one year follow-up. When they looked at the vertebral compression fractures, there were significantly more in the control group than there was in the study group. They also, as expected, found an increase in the bone density in the study group. And then also improved patient outcomes at nine and 12 months. This is a more recent paper. It came out in 2020 out of the Kaiser Group looking at their National Spine Registry. It looked at patients who had been treated with bisphosphonates for either osteopenia or osteoporosis at least six months prior to their surgery. And what they found or what they were looking for mainly was at operative non-unions. There were none in the bisphosphonate group for the osteopenia patients, seven in the control. And that's compared to in the osteoporosis group, there was three in the bisphosphonates and four in the control. So what they concluded is that the bisphosphonates did not have an effect on operative non-unions compared to the controlled. And this does correlate with several prior studies, including a randomized control trial that it just showed that bisphosphonates did not have an effect on a fusion level. I think one caveat for this study and something that I picked up when I was reading it is that they did heavily use BMP in these patients. So about 75% of the people undergoing these fusions had BMP used. And then lastly, on the bisphosphonates, this is a recent meta-analysis that was published this past year, looking at three randomized control trials and four non-randomized control trials. And what they showed overall is that bisphosphonates had a higher level of fusion, less compression fractures, less pedicle screw loosening, as well as less cage incitings. Moving on to the anabolic agents, there's teriparatide, which has been around for a while. It was FDA approved in 2002. And then more recently was abaloparatide, which was approved in 2017. These are anabolic agents. So what they do is they promote one formation and inhibit osteoblast apoptosis. This is an interesting picture below that just shows the bony growth that you can see with treatment of these medications. A caveat with these medications is they should not be used with anyone that's had prior skeletal irradiation because there is a slightly increased risk of osteosarcoma that was found in several rat studies. And several papers have looked at teriparatide because it's been around longer and it results on spinal fusion. This is a paper that looked at patients compared to teriparatide to bisphosphonates. And what they found is that the teriparatide group actually had higher bony fusion rates and a faster fusion. This paper again compared bisphosphonates to teriparatide. And again, teriparatide had increased pedicle screw fixation with less loosening in that group. And then lastly, looking at the insertional torque was better in the teriparatide group than just a control group. The one paper I could find on a bowel paratide, and again, this was just recently FDA approved, so there's not any significant clinical data. So this is a paper for spinal fusion in rats, but they did show a higher, a two higher fold fusion rate compared to controls, although it was not significant. And then the last anabolic agent is a new agent that was just approved in 2019, bromosomab. It's a monoclonal antibody against sclerotin. It increases the osteoblast activity, so you are going to have an increase in bone density, just like with teriparatide and a bowel paratide. They're saying that it's a rescue drug, so it can be used for people that have very high risk fracture. So that was that second flow sheet that I had shown from the endocrinology guidelines. And it is an option for treatment in people that have already been treated with a teriparatide or a bowel paratide, or if people have had prior skeletal irradiation, because that would preclude them from using a teriparatide or a bowel paratide. Dinosumab or Prolia is also a monoclonal antibody. It inhibits osteoclast absorption of the bone. It is an injection. There are some of the complications there. There's not really any significant literature on just dinosumab itself. I did find several papers looking at teriparatide in combination with dinosumab, but I couldn't find any just solely looking at dinosumab and its effect on fusion. But the combination of these two medications did have a higher rate of fusion at six months, but it was similar at the 12-month mark compared to controls. Calcitonin is a medication which alters absorption of calcium. There is an increased risk of malignancy by the FDA. There's really no data that I could find looking at calcitonin and its effect on spinal fusion. However, it has been used to reduce pain secondary to fractures, and this is for an unknown mechanism. And then lastly is raloxifen. This is a selective estrogen receptor modulator. It stimulates an estrogenic response in the bone tissue. As we all know, these medications are often increased risk of DVT or PE. And again, there's limited evidence that I could find in the published data looking at its effect on spinal surgery. So I think really I had talked mainly about preoperative optimization of these people, but there are some surgical considerations that we should all think about when moving forward with patients, especially if they do have known osteoporosis. The pedicle screw options we have available to us, they have, you can use an increased diameter, which increases the pull-out strength. You can use HA coated screws, which also improves the bone screw contact or bony ingrowth. You can use cement augmentation, whether with a fenestrated screw or a solid screw. There are some expandable screws that have been shown to increase pull-out strength. And then you can also consider a vertebroplasty at the UIV or the UIV plus one. Biologic considerations, again, we all know there are several options in this area. Whether or not to use these is kind of up to every surgeon and they know what they kind of use mostly and what works best in their hands. But again, just knowing our options and what we can do to try to facilitate some of that fusion. And then lastly, maximizing outcomes. Again, some of these are just kind of basic spine tips that everyone knows. But I think the biggest thing is that we want to prevent osteoporosis. So some of those basic general good bone health things are things we should talk to our patients even before we start worrying about them having osteoporosis. I think getting these patients referred to an endocrinologist immediately or either diagnosis or optimizing their treatment prior to surgery would be the best case scenario. When we think about our actual fusion, if we do longer constructs or giving more points of fixation, avoiding obviously constructs that stop at the junctions, using hybrid constructs can improve strength, adding either iliac or sacral fixation to help with stability, considering anterior column support to increase the load sharing, thinking about the trajectory for your screws, trying to get the best purchase possible, and then some other tips that we all know. So in summary, I think that we all know that osteoporosis is an increasing issue that we are all going to be dealing with for some time to come. Again, while we might not be experts in the medication and what's available, I think we should all know the kind of at least basic classes that are available, how they can affect our surgical fusions. As of right now, based on the guidelines from the endocrinologist, I think their first line for just basic risk patients would be bisphosphonates. And then second line would be teriparatide. If you do have a patient with a severe osteoporosis or at higher risk, then teriparatide or avalobaritide might be your best first option. And there's also the non-surgical modalities for management that we discussed. And then using this data to help us with our preoperative planning, to try to get successful surgical outcomes, and then considering different technical options that we have to try to enhance our fusions and prevent any of these adverse effects. Thank you. Thanks so much, Dr. Miller. That was a wonderful review of osteoporosis and spine surgery. Next, it's my great pleasure to introduce Dr. Christopher Schaffrey, who will speak to us on complex case discussion and spinal deformity. Dr. Schaffrey, as we all know, is a global authority on spinal deformity correction. He's a professor of orthopedics and neurosurgery and leads the Duke Department of Spine Surgery. He is a past president of the AANS and a past chair of the spine section. So it's a pleasure to have Dr. Schaffrey speak with us on spinal deformity. Thank you, Zoe. Thank you for the kind introduction. And it's a real honor to be part of this amazing, amazingly informative session. So what I was asked to do was to show a couple of cases and then give information related to the cases. There's a certain amount of polling that's gonna go on. And when we heard from Reg Haidt's great talk earlier, there's clearly more than one way to do something ideally, but I think the concepts of what you're trying to achieve become important to know. These are my relevant disclosures. And I think that I've done some development work for deformity-based systems for both Medtronic and for Nuvasiv. So the first case is a 61-year-old woman who has had multiple different surgeries. Originally had surgery as an adolescent for idiopathic scoliosis, had several revisions due to an infection that had several different lumbar surgeries that have been done, and she presents with significant back pain and difficulty standing upright. She's finding that she's leaning forward when she stands any period of time and leans over towards the right side. She has minimal radicular pain, really no symptoms of neurogenic claudication. So what's happening, and this is her CT myelogram, and you can see from the vacuum phenomenon, despite three lumbar operations, that she is vacuuming in her L4-5 and L5-S1 discs, consistent with a persistent non-union. And the question is, how do we best treat this condition? She's fairly miserable. Should we do something simple like link the fusions together? Should we do an A-lift and remove the previous pliff cages that were placed? Should she have an L3 or L4 ACR procedure done? Should she have posterior column osteotomies? Because you probably can get a little bit of movement for that. Will that be enough to correct the deformity? Should she have a PSO, probably an L4, an extended PSO at L4? And the next, I'm gonna go back. You can see these are the questions related to this. And if you all would just answer to see what the current climate is for how to best fix this condition, then I'll give you some information regarding what my thought process was. So I think they're gonna come back with a reordering of that. I can't quite see it. There we go. Unfortunately, the screen is really small on mine, so I can't see what people had recommended, but let me just see if I can expand that, which I can't. Well, anyway, so that's a question to ask ourselves. And then the next question with this is this person has coronal imbalance. I think this is something that has been fairly under-recognized and at least some work from Steve Glassman said, well, look, if it's under five to seven centimeters, it's probably nothing needs to be done. So do we do nothing for this? Do we correct it through our posterior column osteotomies? Do we wanna do a correction through a PSO? Can we correct it through an ACR? Do we wanna use something additional like a kickstand rod to push the spine over or do we need to use multiple techniques? And this is the next question to consider. So basically what I did for this case is I did a revision T3 daily act. I extended up higher because there was a little bit of degeneration in the proximal disc. I did a right-sanded kickstand rod to help with the correction. I did an L4 extended pedicle subtraction osteotomy and I used multiple rods to reduce the risk of rod fracture. And you can see that there are five total thoracolumbar rods that are in place. And how did I come to this decision to do this case? So how do we determine what the best technique is for an individual patient? So We all recognize that one of the principal drivers for spinal deformity is the loss of lumbar lordosis. What has been shown is that most lumbar lordosis should occur in the lower part of the lumbar spine, typically either L3-S1 or L4-S1. As you lose this lumbar lordosis, it's very closely correlated with the development of symptoms. If you do not correct this loss of lumbar lordosis, there's a very high incidence of persistent symptoms in the development of proximal degeneration. What's happening, the principal measurement that we need to understand, and you'll see this as I get into the Rousselet classification of spinal deformity, is the pelvic incidence. The pelvic incidence determines the amount of lumbar lordosis. This sets the shape for the rest of the spine. If you have a low pelvic incidence, you have a vertical sacrum, and you have a high pelvic incidence, you're going to have a horizontal sacrum. Where you put your lumbar lordosis is going to be, in large part, dictated by this, which I'll show you in some subsequent slides. Basically, what happens is by knowing these three factors, if we know the relationship between the pelvic incidence and the lumbar lordosis, we understand the amount of pelvic retroversion, which is a compensatory mechanism to show how much any individual is trying to compensate for a spinal pelvic mismatch. If we know the sagittal-vertical axis, which is another measurement of the severity of mismatch, we have a good understanding as far as what measurements we need to do, and how we may need to correct a specific deformity. There's a very close correlation between these parameters and health-related quality of life issues. Again, this is showing the same thing in a manner. What happens if you have good spinal pelvic balance, you have the most economical stance posture, and this is why people who are really well-balanced have so little pain because they're not trying to compensate for their different mismatches. These are the three highly correlated measurements as we've discussed. There's a bunch of research that's gone behind this to show how important this is during the assessment of spinal deformity, but also how if this is corrected, that patients will improve. This is the basis for the Scoliosis Research Society SWAB, Adult Deformity Classification. By knowing these measurements and us trying to generally get close to these is a good starting point to understand what the goals are, particularly for younger adults. Now, what's happening is we understand what we're talking about. The ideal lumbar lordosis should be within 10 degrees of the pelvic incidence in young adults. If you're 35 years old, this holds very true. But unfortunately, what happens is that there are other factors that come into play. What happens is that people who have a very small pelvic incidence, this is before any other surgeries, they need more lumbar lordosis to compensate for their spinal pelvic alignment. On the other hand, people who have a very large pelvic incidence, this is approaching the 70-80 degree range, they need less lumbar lordosis to be well aligned. The average person you want to match them for patients with a small pelvic incidence, you want to do a little bit more. People with a large pelvic incidence, you probably can get by with a little bit less for the average young adult. This is something to consider when we're treating this patient. This patient's in their 60s. I used to think 60s was old, but now I think that that's more in the middle age classification. What's happening is that the consequences of not restoring lumbar lordosis the proper amount are pretty catastrophic. In this particular study, what they found was looking at people who were having 1-3 level fusions for degenerative spinal anesthesis, what they found was that if you did not restore the appropriate alignment, the adjacent segment degeneration was present in over three-quarters of the patients. What happens is a lot of times you do a small surgery in trying to avoid something major. If you don't restore it all across these smaller segments, you're going to end up resulting like this lady clearly showed with a much more substantial problem. We do realize that two-thirds of the lumbar lordosis in general should be between L4 and S1. That's the consequence of doing, and you saw she had a pliff at L4-5 and L5-S1, and she actually lost lordosis with that operation, which set her up for the variety of other different problems. What happens is we have to understand what the contributions are from the various vertebrae from their discs and vertebrae. But in general, if you remember the two-thirds rule, you'll generally do pretty well as far as estimating what degree of lumbar lordosis should be present. Now, what's happening is that again, the amount of correction we need to get and where it's corrected depends upon whether someone has a low pelvic incidence or a high pelvic incidence individual. If you have a low pelvic incidence, you really want to enhance lumbar lordosis between L4 and S1. If you're an average pelvic incidence, you still should emphasize that, but it's not quite as important, and people will tolerate lumbar lordosis, for example, at the L3 or L3-4 disc. Finally, if you have a very high pelvic incidence, the importance of lumbar lordosis from L4 to S1 is lower. Again, people will tolerate the apex of their deformity being at the L3 level. For example, with this patient, if she had a very high pelvic incidence, she might be a much better case for an anterior column reconstruction, an ACR procedure at the L3-4 disc, for example. That's certainly a consideration and something should be added into the factors when you're deciding how to go and correct a spinal deformity. These principles have been really elegantly defined by Pierre Rousselet and his various morphotypes of the spine and pelvis. If you look at the histogram over here at the bottom right portion of the slide, you can see that there's these different types. Generally, in the bottom left-hand of the slide are patients who have a low pelvic incidence. On the right side, the dots in the purple, people who have a very high pelvic incidence. Again, where you're located and where this should be is dictated by these different morphotypes. For example, if you are a low pelvic incidence person, the apex of your lordosis is, in this case, the type 1 type spine shape is at the L5 vertebral body. If you're a high pelvic incidence, and that's best example by type 4, you can have your apex of your lordosis be at the base of the L3 vertebral body. For example, for a type 1 person, if you do this with a very low pelvic incidence, that's a person that probably would benefit from a-lifts at L4-5 and L5-S1 to really restore the lordosis in that location. If you're a type 4 person and has a high pelvic incidence beforehand, then an ACR would be a wonderful option as would a pedicle subtraction osteotomy at either L3 or L4 would both be good choices. What's been shown is that by doing this, and this is called the GAP score, by doing this, it has a real high association. If you're well-aligned, that you have a very low incidence of complications. If you're mal-aligned, you have a real high incidence of doing it. You want to be able to have this proportionally rated. For example, if you are well-aligned, well-proportioned, then the risk of mechanical complications such as PJK is about 6 percent, but it's far, far higher if you're mal-aligned. This is some additional information looking at these different points showing the importance. This shows a long fusion case, but you can see that the PJK, which occurred at the cervical thoracic junction, was directly attributable to the lack of lumbar lordosis in the appropriate location. You can see that the apex is at L2, where the apex really should have been at the L4 level and resulted in this problem. You can see the results from that. What's happening is if you have a well-aligned spine, and we're talking about PJK, and you're going to see a little bit more about this in the next case, that you can reduce by two-thirds the incidence of PJK by having your spine well-aligned. Work through the ISSG is shown exactly the same thing. Working down lower reduces in most cases, particularly those who have a low pelvic incidence, the risk of PJK occurring. Now, the second factor that's taken into consideration for realignment is the age of the patient. What has been shown is that when we look at things, and this is some work through the ISSG, that you can see the amount of realignment, the aggressiveness of realignment decreases as you age. You don't have to get the same degree of decompression in somebody who's less than 35, that you need a lot more realignment precision than you do somebody, for example, that is greater than 74. One of the factors is that younger patient require a more rigorous alignment than older patients. Again, if you over-correct, particularly in the elderly, there are some catastrophic consequences. What's happening is that this isn't easy to do, and then the ISSG, which has a bunch of very experienced surgeons, that basically only a third of the patients were able to achieve appropriate age-adjusted alignment thresholds. Those who were under-corrected had worse clinical outcomes, but those who were over-corrected had a much higher risk of mechanical complications. Corrections beyond age-adjusted thresholds does not have significant benefit, and in fact, it's highly associated with the development of PJK. This is some more work, again, looking at the same factors, showing that if you correct appropriately, the risks of having a problem are lower. Now, this leads into the second case. I think it hits on some of the points that Dr. Miller made so well in her last talk. This is a 76-year-old woman with lower back pain and difficulty standing upright. She's been bending to the side for overtime. She can only stand for less than five minutes. I was concerned because of her bending and the very rapid progression of this, that she might have an underlying neurological problems such as Parkinson's. She was evaluated very closely for this. You can see her different measurements, including her increased thoracic kyphosis, which is a real concern in somebody that's 76 years old. You can see this is a CT scan. This is her MRI scan, which shows she doesn't have extensive stenosis. This is a more of a camp dichromia picture, again, showing the results from the CT myelogram. I put her into four months of aquatics physical therapy, and you can see she's a little bit better with that. We underwent a very extensive medical evaluation, including a DEXA scan, which showed that her T-score was minus 1.8. Despite that, we treated her with teriparatide because of that. She had an extensive cardiac workup. And the question is, the next poll question, is this patient a surgical candidate in any of your hands? Yes or no? So while they're doing this, I'll continue to march along. And one of the questions that I have when I'm looking at a patient, whether they're a surgical candidate, is looking at their frailty. And what happens is frailty, I think, is an increasingly well-understood concept, which really shows the ability to bounce back from major stresses, such as a major deformity surgery. And the fact is, both of these patients are 79 years of age. And the question would be, are these the same people to do an operation on? So it's not clearly only the chronological age. The chronological age, I think, again, this gets into the concepts of frailty. And the question is, can we alter frailty to either make the patients better to avoid surgery, but can we also alter frailty to make them a better candidate? So this is our Duke system here. So everybody gets into a program of prehabilitation. We draw these labs, a complete blood count, a metabolic panel, anemia panel, albumin, vitamin D levels, hemoglobin H1Cs, on all of our patients. And we put them through a vigorous screening and optimization process if any of these are abnormal. So if you're going to do this surgery, what should it be? Should it be, no, absolutely, I'm not gonna do it. The worst of her curvature is from T10 to L4, but you recognize she's got increased thoracic kyphosis. Should she be done T10 to the ileum? Should she be done T3 or T4 to the ileum? Should she be done, placed in the cervical spine because she has camp to cornea, or should there be some other level that we choose? So we'll give a moment for the polling. Again, I can't see it very well. It may be no surgery, which again, is something that is a consideration. But this is what I did. This is three days post-operatively, and why I'm taking a three-day post-operative X-ray is because there's clearly something gonna go wrong. But this is her three days post-operatively. And I looked at it and I said, boy, that looks pretty good. But if there's a problem, it is that I did not adequately restore the lumbar lordosis at the lumbosacral junction. The rest of it looked good, and I may have slightly overcorrected her thoracic kyphosis. So here she is six weeks post-operatively, okay? And she said she was lifting something and felt a little bit of a pop. And you can see that she's clearly developing proximal junctional kyphosis. She's got wedging of that top T3 vertebrae. And the question is, what should I do? Should I put her in a collar and observe it? Should I extend this to C7 or T1? Should I extend it to the mid cervical spine? Should I extend it to C2 or should I extend it to the occiput? So I'll give a second for you guys to discuss this. And I think that most of us who do a lot of adult deformity, probably have one or two people that are fused from the occiput to the pelvis. And I'll tell you, they are very, very debilitated by that type of a surgical intervention. So basically this is what I did. This was an extension up to T1. And fortunately I did this fairly acutely. And because of that, I was able to get good correction in her particular case. So how do we avoid PJK? And there's some factors that you can't. Older age by itself is not modifiable, but frailty is. And it's been shown that more obese patients are at bigger risk of PJK. Those who have comorbidities leading to frailty is associated with PJK and older age is done. There are operative factors. So the greater the magnitude of correction is important. The amount of residual malalignment, if you under correct them and or if you over correct them, that's an issue. And it's been shown, for example, in this patient, for those patients who have more than 55 degrees of thoracic kyphosis, there's a very high risk if you stop at the cervical, probably at the thoracolumbar junction. So there's different factors as far as rod alignment. You can see in this particular case, the rod isn't bent into the thoracic kyphosis, which has been considered a factor. And there's some belief that the muscle dissection, the set joint violation are all associated with it. So these are the techniques that I've done to reduce PJK. Some things I've tried and have not worked. I've tried doing a soft landing where I put books. I've tried interoperative vertebroplasty at the top couple of levels, which hadn't worked well for me. But what's happening is I've learned the things that have worked is to avoid overcorrection of the sagittal alignment and have an age specific. I wanna have the rod bent into the right orientation. I wanna have a physiological lordosis following the Rousselet criteria. And in certain cases, the addition of a ligamentous support through a tether has been a help. So what's happening is these are some of the studies have looked at things like using hooks for a soft landing. I've tried them. And if you look at the literature, it just hasn't been particularly successful. The use of prophylactic vertebroplasty in for as far as early PJK has been shown some potential benefit, but this study and others out of Johns Hopkins, which really is the leaders in this area have shown that many of these patients eventually develop PJK up to a third of the patients by the use of this technique. So we try to look at this a little bit more academically. And this is some work that was done looking at finite element analysis on the impact by using a variety of different techniques. And what we did is we looked at the segmental motion. We looked at interdiscal pressure. We looked at the pedicle screw forces and did that. And that led to my beginning to use polyethylene tethers. And this is some work looking at Justin Smith in my patients, this was by Tom Buell. And this showed that technique of a simple, this time was a polyethylene suture material that was tensioned by distraction of a cross-link. And you can see that it reduced the incidence of PJK by about half in my patients. And again, shows some of the differences. So one of the questions is how far up do you do? How tense do you make this? This was again, another finite element analysis. And what we found was a preload of about 50 Newtons was sort of the ideal weight, ideal tensioning. And a UIV plus two configuration is what mitigated PJK the most. And this is a video. This is in operative neurosurgery. And there's a long video that shows the exact specifics of the technique. But in summary, what you see here is what we did is this type of a configuration to a device that was able to be tensioned. We tensioned it to 50 Newtons. And this again, shows a post-operative radiograph. And using this technique, we looked at it, this was Chris Ames using a very similar technique where he did a kind of a weave technique and showed a mark reduction in PJK. So our ISSG group looked at a lot of different factors. And what we found in our group was if you perfectly age adjusted and gap adjusted alignment of the spine, the addition of a tether or an implant or a hook or a soft landing or vertebroplasty really didn't add very much, okay? If you had it perfectly aligned. However, if you were somebody that didn't perfectly align it and sometimes it's a bit difficult to tell in the operative table that you can see that by adding a tether in particular, it reduced the PJK rate by two thirds. So this PJK issue remains a major problem. You know, the etiology are incompletely understood but we're understanding that alignment, bone quality, fragility, muscular envelope are all very important. You wanna avoid over-correcting. You wanna do age adjustment and gap adjustment alignment. You wanna contour the rod at the UIV into the kyphosis. You wanna store lordosis more caudally and when you have any question, I think adding a ligament of support tether has been shown to be advantages. So basically there are the high points from my talk. There's a lot of different ways to be able to go and do it. But the fact is that I think that I've made the points and I've got four seconds left. So I'm gonna end at this juncture. Thank you. Wow, it's impossible to follow Chris Chaffee. That was a tour de force. So now we're gonna go to the other end of the spectrum of the world of spine, which is endoscopic. And Nathaniel Brooks from Madison, Wisconsin and I are gonna talk briefly about endoscopic techniques. We're gonna go in a little bit of reverse order. I'm gonna talk about fusion and he's gonna, I believe, talk about decompression. So thanks for hanging it to the end, hanging out with us to the end of this Zoom session. So these are my disclosures. So I just wanna reiterate this power of endoscopy issue. I think that if you haven't tried to use the working channel endoscope, I think you're missing out. The endoscope allows us an incredible amount of leverage by being able to work through this quarter. It really doesn't matter how big or how small the patient is. It's really easy to do these surgeries. And I'll give a shameless plug to Christoph Hofstetter, one of our former fellows. This is a book he involved me in and it is a fantastic work. As he said, there would be no BS in this book. It's gonna be all real neat, real information about how to do endoscopic surgery. And I could tell you that it's generally divided into the transforaminal and interlaminar approaches for the lumbar spine. And I'm gonna focus on the transforaminal approach because currently there's nobody doing any interlaminar endoscopy for fusion. But I'll draw your attention to the most popular lumbar fusion procedure, which is called a T-lift. And the T in T-lift actually stands for transforaminal, according to Harms. It's not a pliff, it's a transforaminal interbody fusion. And we worked together, Lou, Tumi, Ellen and I on this concept of the Kambens prism and understanding how you go through the transforaminal space or the extraforaminal space. And it's traditionally bordered by the exiting route, the facet joint medially, and then the end plate or the bottom of the disc. Now, there are a lot of transforaminal approaches. As I started to get deeper into this, I started to realize that there are multiple approaches available. And here's some diagrams. So if you think about open surgery, like open T-lift, right? What you can do is you can expand the triangle by simply retracting the dura. So open surgery allows you to pull that one dimension, that vertical dimension of that triangle medially, expanding the overall size of the triangle for decompression, disc resection, and also cage placement. So you can retract that dura. Now, if you do something like a tubular T-lift, you're probably taking away less bone coming from outside in. So now your medial confine will be the bone removal, the facet removal, and not the dural sac itself. And so that's a little more limiting. And of course, true percutaneous or endoscopic approaches rely on the native anatomy, meaning you're leaving the facet alone to get that approach in, right? And so this is what it looks like. And there's multiple approaches through this native endogenous zone, if you will, without significant bone removal, right? And so we started to talk about these different approaches, like an endoscopic 1A access. This is an approach that is intended to get to the centrum of the disc, like with a discography or with an endoscopic fusion, and other approaches like 1B, which is well-suited for a foraminal disc coming somewhat caudally and targeting that extraforaminal space, and a 1C access, which actually lies dorsal to the fecal sac, getting you central to the canal for central canal decompression, ligament and flavum removal more centrally, because you can avoid the DRG in that manner. So this video kind of shows what we do with fusion. This is an awake fusion. You can see here endoscopically assisted. There's a PARS fracture, an L3-4 PARS fracture in spondy. And what we're going to do here is we're going to do everything essentially percutaneously endoscopically. We're going to access with a spinal needle into the disc space through Kambin's triangle, docking just lateral to the central. You can see I'm feeling my way through, feeling my way and slowly dilating that up. And I want to stay as medial as possible. The reason being is that as you start to really horizontalize your approach, you get closer and closer to the dorsal root ganglion. And that's really your enemy here. The only structure truly at risk in these approaches is going to be your DRG. And in this particular case, what we're going to do is we're going to lift that inner body space up. So here we are. We're going to use the endoscope to leverage a fusion. We have to dilate up to a minimum of six millimeters. So think about that working channel being six millimeters, right? And that allows us to access with a standard working channel transframmable scope. We're going to go in here. And one of the beauties of doing endoscopic surgery is that the ability to see really deep inside the body, the brilliance of the color, the illumination, clearance with the fluid of all this material and being able to see the exiting nerve root there really is spectacular. So here we are working around that exiting nerve root, taking away disc material, cleaning it out. And it will allow us not only decompress the nerve root, we can also remove bones selectively. And we can also get that end plate cleared for fusion, right? So after that, we're going to go into a slightly larger working channel, about seven and a half. And this allows us to use portals that allow larger instruments for more efficient disc removal. We're going to be able to use a combination of curettes and brushes. First, we drill to make sure our access is good, make sure just like a standard T-lift, we can reach to the contralateral side across the midline and then automated punch curettes to clean off the end plates, free it of cartilage and automated brushes. These are stainless steel brushes that allow you to clean out the disc material. And you can see that this becomes an extremely efficient way to manage this problem. You can see what the system a drill here, we are entering with the brush. That video shows how it looks on the fluoroscope, cleaning the end plates. And then we check our disc removal. So this is a way of using OmniPIG to check with a balloon to be sure you have good disc removal. We can see a little bit of disc that we're going to go back and get on the contralateral side. And then expandable cages. So we're going to access to allow for expandable cage placement. And then finally, screw placement as well. So here we're leveraging off-label BMP. BMP has resulted in an extremely high fusion rate. That BMP is going to be placed the contralateral side away from the nerve roots. Very important because as we expand our cages, we're doing this without direct visualization, right? We're doing this and we don't want to push that BMP up against the nerve roots. So we want to go all the way deep with the BMP, get to the other side. And now we use an expandable cage here. We're using Spinology's OptiMesh. Gives us tremendous power like hydraulic jack to get inner body distraction and whatnot. And then we use our standard percutaneous screw technique. We're going to close that less than one centimeter incision for access for the decompression, disc removal, inner body fusion. And then we're going to start to place our Jamshidi needles. Now we usually use one step screw systems. This is an old video from about seven years ago when we first started doing this. Accessing under AP view, going two centimeters into the pedicle without passing the medial walls. And we're using X-Borrel as well for local analgesia. So you'll notice we don't use a bovie. There's no bovie cautery, no bipolar. So we're just using local injectable anesthetics with epinephrine and that gets us excellent hemostasis. Because again, these are all really, really tiny openings. And people ask, well, how does this really help you? Well, you think about when you're operating on patients who are taking aspirin or maybe they're taking certain anticoagulants that can't stay off their anticoagulants. We don't worry much about bleeding. Certainly they need to be off their anticoagulants for a little bit, but we can quickly get them back to that because we have essentially no fear of things like epidural hematoma, CSF leak, all those other potential complications and issues in terms of trying to get the correction done. So the whole surgery again is very rapid. We're able to get this done. And the endoscope is really critical. I think that the endoscopic piece of this is what makes this different. If we were just purely doing a percutaneous fusion, you could say, well, are you actually preparing the end plate properly? Are you actually able to get enough decompression of the exiting and traversing nerve roots, right? So this is an interesting technique and we've been able to do this a lot. And over 300 cases, we've done about 330 cases now at University of Miami. And people ask me, well, what is it like when you do these surgeries and why would I even bother because it's so hard to learn or I'm not used to it? And here, I'm gonna show you examples of this. This is Mike Wang against Mike Wang. These are both a T-LIFS MIS. On the left, you'll see a traditional MIS sort of tubular T-LIFS done under general. And on the right, you'll see the awake endoscopic T-LIFS. So I'll just show you how it looks in my operating room. This is taken off Epic, of course, patient de-identified. So let's start to track these events. So on the asleep MIS T-LIFS, I'm in the room at 725 and it's a good day. So for the awake fusion also 725, by the way, different days. It's not me against a fellow or resident or anything like that. So in the asleep patient, we need to get an A-line in sometimes, IVs, intubation. This is pretty quick, 749 for Miami. That's pretty darn quick. We're ready to get going. Of course, for the awake fusion, they can just flip themselves over. So, you know, they're ready to go at 732. And then we're gonna get to the procedure start, 8 a.m. versus 738. Procedure finish, 1056 versus 830. And of course you gotta wake the patient up. So that's the difference of 11 a.m. versus 835. So that's T minus 121 minutes for the first case of the day before turnover. So just to give you some idea of that power, if I save 151 minutes, I'm sorry, 151 minutes was per case, then I'm looking at, if I do 100 of these a year, I'm gonna say 15,100 minutes, which is gonna be 251 hours, which is 10 days a year, 24 hours a day, counting to basically something like that. So you start to see the power of what we do. Hopefully you guys will be able to see this maybe live at one of our upcoming meetings in the future. I wanna give a shameless plug to our neurosurgery podcast as well. Please have a listen. So with that, I'm gonna move on. Great, thanks everybody. My name is Nathaniel Brooks. I'm a neurosurgeon at the University of Wisconsin in Madison, Wisconsin. And I'm very proud to be invited to this great collection of speakers. This has been a great group discussing all sorts of different aspects of both navigation and minimally invasive and maximally invasive surgery today. So I'm gonna talk about a slightly different aspect of using the endoscope compared to Dr. Wang, which is decompressive techniques. And I basically just chose one technique to discuss today just because this is what I consider to be essentially the starter case. This is the case if you're gonna pick up endoscopic spine surgery where you wanna start a simple lumbar microdiscectomies. And I'll talk about the technique and what kind of cases to pick. So the interlaminar approach is a minimal access approach to the lateral spinal canal and used in similar situations to a traditional open microdiscectomy. And the nice thing about this and the reason that I, because I largely self-taught in this, using this procedure is that I felt that not only I had a good understanding of the indications, but also that you could easily convert this to an open procedure if you're feeling like you're not getting enough of the decompression done or you have some concerns intraoperatively. So it is, if you're going to pick up an endoscope and start working with it, a good way to start because you can always convert. Indications are L4-5, L5-S1 disc herniations, typically looking for a large interlaminar window, which is denoted here on this image with that red outline. And that gives you the opportunity to access the disc pathology without having to do any drilling, which is probably a couple steps harder than just the typical endoscopic procedures. Of course, the usual indications of a minimum of six weeks of conservative care. And it's nice to pick patients who are younger, who've had their disc herniations for shorter periods of time, because early on it's a bit more of a challenge to figure out how to deal with calcified discs and those kinds of things. Equipment that you need are endoscope, excuse me, endoscope camera and monitor. So we use actually the same monitor and camera as the general surgeons and orthopedic surgeons use for their procedures. Irrigation system is also the same as what the orthopedic surgeons use. And then fluoroscopy, which is again, of course, the same. So no additional capital costs for that. Typical capital costs really only relate to the endoscopes and acquiring those. Setting up the scope is pretty straightforward. There's the coupler for the camera, light source, and then just to speed up the talk a little bit here, that you also attach an irrigation source. The surgeries are done under constant flow irrigation, which allows visualization to be improved. You don't have as much trouble from bleeding and things like that. Positioning is the same as you would do for a traditional open lumbar microdisc. You're gonna do a prone positioning, Jackson table, if you have that, or if you can use Bardeen's, both are possible as long as you can get good fluoroscopic images. Localization is done simply by localizing the intralaminar window or on the side of the disc herniation. Typically trying to target the midpoint of that intralaminar window so that you have good access to the lateral aspect of the lamina canal. So it's a two-step approach. Of course, you make an incision and then also place a tissue dilator. And then over the tissue dilator goes what looks like a miniaturized tubular retractor as Dr. Wang was describing. That essentially looks like a tubular, very small tubular retractor. You can see that in this fluoroscopic image it has a bevel on it. And we think about this retractor as actually being a tool. So a lot of people will look at these procedures and say, hey, why are you doing it single-handed? And actually this is your second hand. And the first hand is the tools that you're using through the endoscope. And then the third hand actually is irrigation which we'll see later. So taking a disc out is pretty straightforward. And so the first part is to prepare the ligament and clean up the ligamentum flabum. And then we open or traverse the ligamentum flabum, dissect the nerve root away from the disc and then remove disc material. And then the final step, of course, check your decompression. So starting on the first step, this is as we've doctored tubular retractor and endoscope outside of the ligamentum flabum, just removing whatever muscle might be around or fat. It depends on the patient what this is gonna look like. What you're seeing there is a bipolar electrocautery that helps with both controlling bleeding and then to some extent dissection similar to our monopolar electrocautery in an open procedure. The next step is gonna be traversing the ligamentum flabum. And typically, even when I was learning, I thought this was like the most frightening part of the operation because of course you have this, what's called a micropunch, which looks like a pretty sharp implement and is, but it is shaped in a way that kind of will push away soft tissues off of the front of it. But also more importantly, once you kind of get through the ligamentum flabum here, you actually, the irrigation will flow into the epidural space and push the dura away from the ligamentum flabum. So as we go along here, you'll see that we eventually pop our way through. And you can see that the dura is below. The other thing you can do is do a more conventional approach. You see here where we are, we've gotten through the ligamentum flabum, but you can do a more conventional approach where you actually will use a Penfield-4 or something along those lines to help get you through the ligamentum flabum. Once you get through, you're gonna advance into the canal. You start with the bevel of the retractor facing medially, and then we'll use the tip of it to rotate and push the traversing nerve root off of the exposed disc material. So that is what we're seeing here. At the top of the screen is the spinal canal and actually the traversing nerve root just strung over a disc there, and then a large disc herniation, some epidural fat. One of the troubles with the early adoption of these is that it can be very confusing about what's what because you never see it quite this magnified. Just for the interest of time, I'm gonna speed up a little bit. We would get into the canal. And then at this point, we're dissecting the traversing nerve roots with what looks like a kind of a nerve hook. This is a flexible one that can fit down the working channel of the endoscope, and you can see disc material essentially filling up about two thirds of the screen. So where you're seeing the fat, that's the midpoint of the canal and the traversing nerve root. And once I get to this point, I can rotate the retractor, which I'm doing now, and that isolates the disc from the nerve root, and we can just start removing disc material as we typically do. And then once we get to the end of the disc removal, we just wanna make sure we have an adequate decompression. Again, this is a little bit different when you first learn it. Of course, you wanna try and do it just the way you would do it in a conventional open procedure. And that meant that in the early days, I would use a nerve hook like this and make sure there was no disc underneath the nerve. But as I've gotten more facile with this and learned from others, You can also look for just pulsation of the nerve root as an indicator that you're decompressed. So that can be an easier way to make sure and verify. There is a good ability to move. So you're not, even though you seem like you might be targeted in one position, you can actually swing that scope medially, rostrally and caudally, especially in the larger interlaminar window. So you can get a lot of disc material, even if it's migrated medially or caudally or rostrally. The endoscope, as you can see, is a nice visualization tool. You get a very clear view of neural structures. It's a 25 degree scope. So you have a little bit of confusion about when you're first learning about where you're targeting with your instruments, but you get used to that. And of course, you could see that I could rotate around my tool. So I could actually, it's almost like you're standing down at the bottom of the tubular retractor and looking around your instruments. So you have a lot more visualization capability. That's the size of our incisions, the tiny little incisions. And I do think that endoscopic procedures are very valuable. Of course, they do have limitations and can be a challenge, especially early adoption and learning takes some time. And certainly I think the residents and fellows that I train now will have a much easier time than I did as I was essentially learning gradually over time, but essentially on my own. And then redo surgeries can be a little bit more difficult to do because of distorted anatomy. Migrated discs are a little bit more difficult. So I don't recommend doing that early on. And then of course, your angle of approach to the disc space. So your overall targeting really affects how much disc you can remove in the disc space, which is an important consideration. You just don't have as many degrees of freedom once you're in the canal, depending on how you target from the surface of the skin. So in conclusion, the interlaminar full endoscopic discectomy is an effective, reproducible, minimally invasive approach to remove disc pathology. And most importantly, for those of you who may consider adopting this, I think it's a good starter case to learn. Certainly when I was first training, there was much more gravitation towards the transforaminal approach, which I thought was a good approach, but I was a little confused about the indications and what I was gonna be able to do with that procedure. I felt that the interlaminar approach was much easier adoption for me, just because of the ease of understanding the indications and what I could get done with the procedure. So I have left an addendum of a lot of other things under this talk, just so that you guys can have them. And I'm gonna quickly go through them. So when it's recorded, you can pause and look at them. It just has data, steps to starting, and training. So thank you very much, everybody. So Mike, Nathaniel, thank you so much for those terrific talks. I think for a lot of us who don't do endoscopic surgery, it seems like a daunting task. And that sort of leads me to my sort of first question to really both of you, is how long did this take for you, Mike, to learn this, and Nathaniel, for you to learn this, and how long do you think it would take the average spinal surgeon to acquire this skill? Mike, do you want to start? Maybe I can answer for... Yeah, why don't I answer for transforaminal, and maybe Dan can answer for interlaminar, because they are a little different. I think that I'm still learning. I think that there are so many things you can do in endoscopy. And when you see some of these true masters in endoscopy in China or Korea, they can do some crazy stuff with the endoscope. Like you've probably seen the papers where they're drilling out an artificial disc that's like pushing against the nerve root, stuff that's hard to do in open surgery. Right. But I would say, if you start with the simple cases, you can probably build, like I'm thinking about Meng Guang, one of our fellows from last year, like within the first year, he'd done like 30% of his cases endoscopic. And if you focus on it, you can learn it very quickly, but it is very different. It is quite different. Everything looks different. The colors, the textures of the nerves versus muscle. At first, we thought everything was nerve. We looked at everything, and I said, that's nerve, it's got to be nerve. And then as you get a little experience, you get a little bit smarter. Yeah. I would say my experience was, it definitely, when you have nobody to train you, it takes a while because everything you're doing, you're kind of doing in kind of the, always keep in the back of your mind, you don't want to have bad outcomes and you don't want to have things turn out poorly. And I have all your partners and the orthopedic surgeons say, what are you doing and why are you doing that? But, so I took a kind of a slow adoption pattern to it. Training residents and training fellows, I can see that they can pick it up easier. They just have a little extra hand to tell them that's okay, this is okay, this is a good indication. This is how you set up the drapes, all that kind of stuff. All these things which kind of drag you down and slow you down initially. You know, the interlaminar discectomy with appropriate patient selection, I think it's a very straightforward case. And so you can pick that up. I give people, you know, 15 to 20 repetitions before they feel like they're reasonably solid in doing it. But then when you start to get into using drills and doing things that are a little more complex, I do posterior cervical frame anatomies and things like that with the endoscope as well. Those are just a bit, take a bit more time. But again, just like everything in neurosurgery, when you really look back on how long it took you, I mean, we all trained to do micro discectomies open. And when we were training to do them open, it took us probably years to figure out how to do it. We just didn't recognize it because we were learning how to do everything else all at the same time. So you have to give yourself a little bit of leeway when you're first learning how to do these things. And then I think it's been a valuable technology for me, like Mike Wang and Mike Steinmetz are both using it as a platform technology. So you can take what you learn to do discectomies and do fusions. You can do thoracic discectomies, all these different things that are potentials and can be valuable ways to use the endoscope. So I think it is worthwhile in the end. Hey, guys, great, great presentation. And for all the participants, please use the Q&A box on the right side of your screen to submit questions for San and Mike. And I'll relay that to them. I don't see any. And yet, Mike, I was gonna ask you a question around sort of the superior articulating process. So how do you deal with those patients that have really significantly overgrown facets or really collapsed foramen? How do you get medial enough in order to be safe enough in Kamden's triangle? Yeah, that's a great question, Mike. When people ask me, am I a candidate for the endoscopic fusion versus a traditional open, it's really all about the facets. The bigger the facets are, the more it pushes you laterally, the closer it pushes you to the DRG and the smaller that corridor gets. And because we're so used to just taking the facets off with an open surgery or tubular surgery, you can't really do that easily endoscopically. Now, I know Christoph has done this. He's sat there for two hours and drilled that facet out to make the space. So he says he can fuse L5-S1 transforaminally. But for the typical surgeon, they're not gonna take the time to do that. So when I see a very overgrown, meaning laterally overgrown, not depth, but if it's pushing you out laterally, then you gotta take a very horizontalized trajectory. I think that's a case where you run the risk that you're gonna hit the DRG. The other thing that helps you though is a spondy. So if you're gonna start cases, spondys are great because that drags that, usually L4, right? L4 nerve forward away from your access point. So that makes it a lot easier to do the spondy cases that way. I'm just gonna follow up. All right, guys, there's a question. Oh, go ahead. So I also had a question. Go for your question and I've got one from the audience, but go ahead. Okay, quick question for both of you. CSF leak, you guys probably don't have them very often, but what do you do? I'll say in my experience, the only times I've had them are in redo cases. And as you can see, those tools look giant on the screen, but they're very tiny. So I've actually just left them alone and haven't actually had any patient who's had anything symptomatic occur from those. So that's been my experience. And the only times I've had them is in transfer animal cases. Those are usually the ones I'm doing revision cases from a prior disc or herniation or something like that. So there is some scarring to help you as well from that. Yeah, I have the opposite experience probably just reflects our experience. So the only ones I've had were interlaminar. And yeah, no, I did have to take one patient back and have to fix it sort of mini open days later. But I think, yeah, they're quite rare. Christoph Hofstadter talks about the third hand, meaning the pressure of the irrigation, keeping the dura kind of away from you, which is a really nice feature. Great. Hey guys, I've got one question in the Q&A box. Please participants send questions if you'd like for our panel. It has to do with endoscopes and maybe I'll rephrase the question a little bit. And can you comment on the endoscopes that are available? Maybe the pros and cons. The question specifically asked about sorts, is that the best scope that's out there? But do you wanna comment maybe on scopes, maybe some of the benefits that you see in some of them that are out there? I know it's kind of a tough question because we're talking about specific brands. We try to stay away from that. I guess my comment so far, I'm gonna be pretty generic about it, but you certainly wanna look at companies that are dedicated primarily to spine so that they're engineering towards spine applications as opposed to being overly, I guess, kind of have it just as a slight spinoff of their company. But I think that just generally speaking, I'd seen this as I was kind of looking into endoscopy over time. I didn't adopt it for about three or four years. And by the time that I did adopt it, every company that I'd looked at three years previously had come up with better drills and better graspers and better tools overall. So I think that there are a lot of good options. You just have to investigate them and look at them and see what works for you. And look at them at meetings and things like that certainly when we come back online, so. Hey Mike, there's one last question. I know we're out of time. Okay, so go ahead. I was gonna ask one more, but I know we're out of time. Sorry, there's a question from Ron Riesenberger from Mike Wang. And that is, can you talk a little bit about the decompression that you're trying to achieve when you're doing an MIS TLIP? Not seeing much ligament and plagum removal. Are you relying on indirect decompression or how do you ensure decompression, particularly if there's some lateral recess stenosis? Yeah, thank you, Ron. I think for most of this endoscopic stuff, we're relying heavily on indirect decompression, but there's also disc removal. And there's also, you can open the frame in and you can spend the time to drill that stuff out. You can really take time to drill and decompress only pretty much on the ipsilateral side. It's very hard to get to the contralateral side transforaminal. You can do an interlaminar like San was indicating. But I think what we're gonna see is that this is gonna change. There is a sweet spot probably somewhere between six millimeters and 14, where we're gonna end up, where we're gonna be able to do a lot more efficient flavinectomy and bone removal that isn't quite so small as what we're shown today and isn't quite so big as what most people are doing. So I think, look forward to that coming out in future meetings at the WNS. I think we are out of time. Mike Steinmetz, did you have any other questions that you wanted to ask? No, thanks. So that was, I was gonna read Ron's question too, so I thought it was important. I know we're out of time, but I thought it was an important question. So thank you for reading it. All right, perfect. Thank you very much, everybody. It was great discussion. Thanks, everybody. Bye-bye. Take care. See you tomorrow.

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