Dr. Sandhu discusses technological advances and evaluation of current and emerging techniques in spine surgery used to preserve spinal mobility.
Faheem Sandhu, MD, PhDProfessor, Department of Neurosurgery, Georgetown University Medical Center Director of Spine Surgery, Medstar Georgetown University Hospital Co-Director Center for Robotic and Minimally Invasive Spine Surgery All right, thanks everybody. It's a pleasure to be here. Pleasure to uh be invited by Dana who's one of our trainees. It's great to see you doing well. And uh you know, just like, uh you want to see your kids flourish and uh go out into the world and uh be successful. It's really gratifying to see that. Uh And uh as Dana said, I, uh you know, I'm really uh focused on minimally invasive spine surgery. So that's kind of the bulk of my practice. But uh but motion preservation uh really makes sense uh in the, in the continuum of uh spine care and, and some of the concepts of minimally invasive spine surgery, which uh really are aimed at maintaining as much function of the normal spine as possible whenever we have to address uh various pathologies. But uh but I think, you know, the spine is a structure that is meant to move and should move when uh uh when we can allow for that. So I'm going to go through, you know, some of the technologies and approaches that we now have to maintain motion preservation in the lumbar spine. I think it's more commonly understood in the cervical spine and more commonly practiced among surgeons, uh, across the world. Uh, but, uh, Lumbar, uh, motion preservation arthroplasty has had a kind of a tainted past and, and so, you know, it hasn't been adopted as readily. Uh, but I think hopefully after you see this presentation you'll realize that, uh, uh, it's a, it's a very viable and, uh, good option for your, for your patients. So, um, uh, you know, I'm, it's, it's not moving with the arrows. Uh, no, let me see. Sorry. Mhm. Mm. Turning up the door now. There we go. Ok. Yeah, slow to respond. Um, yeah, my disclosure is, I do teach, uh, for, for the company that, uh, um, uses or makes the main device that we use. Uh, so, you know, for people with, uh, degenerative disc disease, uh, this is a common problem, especially amongst younger people. Uh, it starts in, um, people's twenties and, uh, extends into their fifties even sixties. But, uh, uh, there's a certain percentage that just do not respond to conservative treatment and, uh, you know, what do we do with these people? So you have to figure out who, who are candidates for surgery and who, who are not. And, uh, uh, we all have the usual treatment strategies of physical therapy, injections, medications and, uh, when, when those people fail all treatments, you know, what, what do we have to offer them? So, it's either you know, uh some surgeons will say we have nothing to offer you. Uh others will offer them fusion. But uh but this is the same group of patients that would fare well with uh disc arthroplasty. Very normal. It's uh it's someone on the team. If you're on the line, you could please mute yourself. Yeah. OK. So yeah, so the goal is similar to fusion. Uh but with uh with disc replacement, you want to eliminate the pain, uh restore disc height, uh maintain the, the range of motion. And then long term, why do we want to preserve motion? It's really to prevent some of the sequela of fusion and that's predominantly adjacent segment degeneration. And you'll hear patients say, oh, I don't ever want to get a fusion. It's gonna cause this domino effect. And you know, then I'm, if I fuse one level, then I'm gonna get another and then another and uh they're not wrong. This is a real phenomenon and you'll, you'll see some of the data but uh but also maintaining motion which should help faster recovery and faster return to work and uh uh uh function and uh in society. Um So like I said, the lumbar, uh Arthur Plasty has a has a very interesting and uh long past, I mean, the first device was uh uh this device, I mean, it was implanted in the US in 2000. Uh but it goes way back to 1982 when it was first implanted in Germany. It was developed by uh uh uh Karen uh Budner Janz who was uh Olympic gymnast and also an orthopedic spine surgeon. Uh but she had the idea that the, as a gymnast, uh the, you know, the spine should stay in motion. Um and it went through several iterations of design and became this, she disc, which was used in the, in, in Europe in the late nineties and then came to the US for uh initial ID study and uh was approved and uh sold um but then taken off the market as well. And uh this is, this was a second generation device and uh differed from the first and it was uh Semicon trained uh uh and uh also developed in Europe, came to the States in the early 2000 with the ID D study and uh the only device to have both one and two level uh approvals by the FDA and then the third generation device uh the trial started uh late in the 4007 and was approved in 2015. Uh And now there's a seven year uh data on the outcomes from this uh from this patient group. Uh This one is also Semicon but has a mobile core and you'll see with the data that uh that adds some advantage in terms of uh uh outcomes and functionality. Um So, you know, comparing the three discs, the first one the she which is no longer on the market was unconstrained device had five degrees of motion. You get a p lateral as well as rotational movement. This was probably a design flaw because uh for the lumbar spine, uh it's actually too much motion and they had a lot of failures if the device was not placed perfectly. Um And uh and there were several reasons why it was taken off the market. One was maybe the design and uh implantation issues. But uh the company that sold, she also acquired prodi and they had to make a business decision, uh which which device to promote and they, they chose to promote prodi because the outcomes were a little better and the safety profile was a little better. Uh but simultaneous with that when they made the change, uh Medicare coincidentally also decided uh to not cover uh lumbar arthroplasty, which makes sense because, you know, Medicare covers uh patients over age of 65. And this really isn't a surgery for people in their mid to mid sixties or or older. This is really a surgery for younger patients. So, um uh that those things happened simultaneously and really hurt the lumbar arthroplasty field. And a lot of surgeons felt, you know, it was dangerous, we shouldn't do it and uh just ignored the possibility altogether unless you were at a special center like the Texas Back Institute which had done all the trials participated in that. And really believed in arthroplasty. And I credit those uh uh those surgeons for helping keep the uh the field alive because it was still a very good uh surgical option for patients. Um The the other devices you can see the prodi is semi constrained. So it doesn't translate in the anterior posterior way as well. But with the mobile core, the new active L does allow for better motion in that direction. Um So in terms of, you know, data, uh arthroplasty, cervical lumbar is the best data we have in spine surgery because there have been so many randomized controlled studies as part of the FDA approval process that this has given us great data on fusion as well as uh arthroplasty. And so there have been at least, you know, I mean, there's 13 devices that have gone through some form of trial, most of these won't ever get approved in the US. Um because of design, I mean, metal and metal devices are never going to get approved because of the hip uh uh history of arthroplasty. Uh some of these elastomeric devices which are lower on the list also probably won't get approved. Uh And a lot of the companies aren't, they, they're very expensive to do these studies. It's like in the order of 30 to $50 million to conduct the study and get the approval process. So uh unless they have a real device that's going to make a difference, most of these won't make it to the market, but they are sold outside the US. So you may see these devices in patients who have had it implanted out elsewhere and then some of them are actually pretty good. But uh for the reasons I mentioned just won't get approved in the US. Um But you know, when you look at some of the randomized control studies and uh pool the data, so do meta analysis and then the power of the, the the data is greater. Uh They, they clearly demonstrate that uh you know, there's a, a better result, uh reduction in adverse results or events with uh arthroplasty than uh fusion and that this was in one study, but it only pooled two randomized studies. Uh uh when uh Ziegler and his group uh pooled uh five of uh of the studies um or actually sorry, four. they, they saw that uh arthroplasty was much more durable and uh gave better outcomes than uh fusion. And um just to break down the data, they, they analyzed all the papers and found four publications that were um worth doing a meta analysis. And when you look at the uh the pool data from all the meta analysis uh compared to fusion from these four studies. So it's basically pro she maverick and uh and then a combined pro uh she sorry. Uh OK. Well, uh but OD I uh va scores all favor arthroplasty over fusion and this is a five year data. So we're looking at patients after five years, um It wasn't quite statistically significant but showed trends toward favoring arthroplasty and same with reoperations. And most of this is, you know, due to adjacent segment issues, some implant issues. Um but that was uh statistically significantly favoring arthroplasty over fusion and same with uh willingness to do surgery again. So, uh uh arthroplasty group patients wanted, they would do it again over fusion patients. Um And then when you look at it schematically, uh the full trend is toward arthroplasty better. Uh And the ones that are statistically significant on this chart and the on the bottom are two checks. And the ones that are trending toward arthroplasty is just one check. But you can see uh when you pull the data together, uh it's more powerful, but uh definitely shows that arthroplasty patients do better than fusion patients and uh in terms of pain, disability reoperations and patient satisfaction. So, not unexpected. I mean, you, uh you assume that it's intuitive that if you maintain the motion, uh you're gonna have less pain and more functionality. So uh the outcomes have been better. Uh There's cost studies that show there's uh uh some cost savings when you do uh arthroplasty over fusion. And depending on uh you know what you're using in terms of cage bone graft material, uh screws rods, but also in terms of return to work. Uh and uh all of that and use of long term medications. And then uh looking at the other uh sele of fusion, the adjacent segment degeneration, uh what did that show in the two groups and consistently whether you look at it at two years of follow up or the five years or, or greater, uh it was about the same, you know, about a three fold difference in uh uh adjacent segment disease if you had a fusion versus uh maintain the motion with an arthroplasty. So, I mean, there's clearly, you know, some age related, no natural history degeneration, which is about, you know, this 9 to 12% that happens over time. But if you fuse the spine, uh you basically triple that uh uh number and increasing the strain and uh forces on the adjacent level. Um So this is real, I mean, our patients that we fuse will develop adjacent segment disease and a number of them will end up needing surgery. Um And uh in the, in their meta analysis, it was uh you know, twice as many patients uh needed reoperation for um uh Jason segment disease. Um uh whereas the radiographic differences were about three fold. So, um not everyone who has uh radiographic change ends up needing surgery, but many do. Um and then the, you know, the unexpected events, the serious adverse events or uh reoperations were consistently less in the arthroplasty group than in the fusion group. And uh and that was true in the five year and also in some of the long, longer term observational studies that were done. Um So now in terms of, you know, who are these patients that uh should get arthroplasty and uh I think uh successive for any surgical procedure, but in particular, uh arthroplasty depends on patient selection. So it's very, very important to, you know, choose the right patient, understand the pathology and uh and then uh treat them accordingly. And then obviously, you know, whether potential complications for any procedure that we do and uh uh many of them start by the patient selection. Uh Some are, you know, technique related what we do during surgery in terms of disc preparation, uh size selection, things like that. Uh and then postoperatively, it could be the complications related to the device or uh or the technique as well. Um And uh you know, so patient selection, you know, obviously for your first patient, you may not want to choose a very obese patient. Uh but uh things like uh previous fusion fracture, uh uh contained non contained disc or, you know, uh migrated disc herniation. These are some of these are relative contraindications. But uh you know, the uh osteopenia, uh you want good bone quality for placing an arthroplasty device. You can't have a mobile spondylolisthesis, uh significant scoliosis, um infection, significant joint arthrosis. So people who don't have healthy facet joints are not great candidates for um uh arthroplasty and then obviously, chronic steroid use autoimmune disease, those things factor into just uh access and uh clinical outcomes, bone quality and then psychological disorders you always want to uh consider in patient selection. Um and a number of other things, I think metal allergies are rare, especially these devices are basically Cobalt chrome with polyethylene core. But some people do have allergies and uh that may need to be tested. Um uh Obviously, pregnancy is not a indicate not a time to be placing these uh but osteopenia. Uh uh this, most of this data is from the ID E study. So which were very stringent in their uh uh selection criteria. But uh they did allow for some people with osteopenia and the cut off was minus one as the T score. Um And I would recommend that every patient that has an arthroplasty, whether they're in their twenties or thirties still have a Dexa scan because you really want to make sure there's no uh osteopenia. Um And uh because this is the last thing you want to see when your patient does really well after surgery and then comes in at their first post op with this X ray of subsidence of the device. And uh uh may or may not require like in a share situation that's uh disastrous because it's an unconstrained device in the newer devices. The 2nd, 3rd generation prodi active L it, it may not require revision but it, it may influence their long term outcome. Um And just another example of visualizing a change cooperatively that may, if you see this, you know, you may want to change uh uh the selection of doing an arthroplasty and convert to fusion. So you always have to have that uh uh as a bailout for patients and, and counsel them accordingly. Um And uh we talked about the mobile spondylolisthesis that sometimes doesn't show up on a, on an MRI scan because they're lying supine. You really have to get uh dynamic X rays for everyone to rule out that they do, they do not have a mobile spondylosis. I get AC T scan as well to look for any potential pars defects that may not show up easily on the on the MRI scan. Um Obviously, people who have significant facet arthropathy are not candidates for uh disc replacement because you're, you're basically just replacing the anterior portion of the motion and you still need to have functional uh posterior joints to maintain the motion. And, and uh if you don't, you'll just, you know, uh have chronic back pain just in a different location. Um uh But people who have had multiple surgeries for disc herniation, uh if the if the facets are preserved, which most of them are nowadays with uh I think uh current techniques of microdiscectomy. Uh These people are actually very good candidates for uh disc arthroplasty. Um And uh that's an example of a patient with recurrent disc herniation that had an arthroplasty procedure. Um uh in a case like this where the facet is missing uh due to previous surgery, obviously not a good candidate for uh arthroplasty. So don't want to do that. And then certainly when you see this diagram in your clinic, uh I don't know if you want to do any surgery, but uh this arthroplasty is probably not gonna solve all these problems. So, um and then uh at least in our area, we use an access surgeon to uh uh get to the anterior spine. This is the picture you should see. Uh And fortunately, my access surgeon provides this view uh consistently. So you want to have access to the complete uh disc and then it makes our job very easy to just do a very complete discectomy and then place uh uh the the device in the center of the disk space. And uh uh there's some contraindications, obviously, if someone's had previous infection, peritonitis, uh uh ruptured uh diverticulum or radiation, they're not great candidates for a retro peritoneal approach. Um um obesity kind of a relative contraindication only because uh it's very hard on your excess surgeon potentially. But uh uh you also want to be sure you can visualize the spine uh with the x rays. So that's uh uh it's critical because you can't place a device even uh properly unless you know, on the x rays where it's going. Um and then uh you know, there, there are other considerations, retrolisthesis. I don't think that's uh that's a contraindication. II, I don't think that's physiologic that uh uh it causes problems. Uh But uh you know, people are concerned about significant dispace collapse. Sometimes uh Schmorl's nodes you have to be aware of. I don't think they're a contraindication. Just have to be careful not to violate the endplate too much. But usually you have enough surface area of the, of the endplate that's still placing an arthroplasty device is, is very straightforward and, and then if you're worried that the, the spine looks small and the device may not fit, it's good to get measurements. Uh I personally never encountered someone who we couldn't fit the smallest device and even in a very petite woman, uh we've been able to put in the the smallest device so it tends to fit uh there, they have size option that tend to fit everyone. Um And uh you know, the collapsed disc of people think, oh, this is not a great candidate for Arthroplasty. I gotta just fuse this. But if the facets are good, you know, it's really technique related about mobilizing the segment and distracting the disc space. But they're, they're actually really good candidates for arthroplasty. And I, I would say this is uh uh one of the ideal situations, these people do very well with the disc replacements. Uh And you can see this is the same patient with uh once the disc is mobilized, you can place um a good sized device and restore physiologic height and uh lordosis to that segment of the spine and, and uh restore motion. Um that this is another example and you can see how it's not that difficult to open the disk space and place a arthroplasty device. It is important during surgery to get a complete discectomy, release the posterior longitudinal ligament and remove as much of the disc as possible. Because as you saw in some of the previous pictures, the device is pushed very posteriorly. So if you have uh some retained disc material, you're potentially pushing it back toward the canal and the fecal sac and nerves. So you really want to do a complete discectomy almost like an A CD FI I personally do it that way now with Bran Jours, uh but you can use a curette and, and pull out that, that posterior round of uh of disc material. And uh and I mentioned this earlier where if there's a situation where you, you can't place an arthroplasty device, whether it's access or violation of the endplate, various reasons, you might not want to place it, then you have to have a bailout of uh of a fusion. So having a stand alone, uh a lift device available is uh is important for any arthroplasty procedure. Um Fortunately, I, I personally have not had to convert any to uh fusion, but uh you, you should always uh talk to patients about that and uh and have it available. Um technical errors. You obviously devices work better when they're in the right place. I mean, you want it in the center of the disk space as posterior as possible. So you know, if it's off to one side, it's not going to function as well. I think the newest generation of devices are a little more forgiving than devices like the she the first generation or even the pro disk. Um But this is probably an era of incomplete discectomy. Uh But also, you know, marking midline, which is an important thing to do during surgery. So you get x rays and the spinous process is actually not the best marker for determining midline. You really want to look at the end plates, make sure they overlap with each other, the vertebral bodies and the position of the pedicle. So they're symmetric on both sides and uh and try to choose the midpoint between the two pedicles. And uh the spinous process is probably the third thing that if it lines up that's fine, but I wouldn't rely on that. It's just the the center point um because people have too much anatomical variation in the lower lumbar spine. Uh And then, and then just aim for midline positioning with posterior placement of the arthroplasty device. Um And so, you know, when you look at the, now the data for the third generation device, which is a little different because the first two studies were done comparing arthroplasty diffusion. Now the third generation device, because there had already been good data with arthroplasty. They just did a trial comparing themselves to the two other arthroplasty devices. So it was uh active L versus prodi and share in the controlled limb. Uh And so, you know, it was for single level uh patients between 18 and 60 years of age and they had to have significant back pain from OSU and the exclusion criteria. We kind of went through that list, but they did allow for patients with previous surgery. So, Microdiscectomy, Heiny laminotomies were still candidates as long as they didn't have too much facet removed. And, uh, and they couldn't have symptomatic degeneration at more than one level. So that's an important criteria for the study. And then, um, and, but they were able to do a subgroup analysis after the study and looked at people who had uh prior surgery versus those that uh uh had no prior surgery and both groups did well and uh uh showed, you know, significant improvements compared to the control groups. Uh And remember this is arthroplasty versus arthroplasty. So, uh this device is just, uh doing a little better than the other arthroplasty. Uh And um, and so it was a durable solution for both uh patient groups, which is nice to know. And then the two year data showed that the active L third generation device was better than the other two devices. Uh long term outcomes and, and that was sustainable, you know, from the earliest time point to the two year of time point. And now, now we're up to five years uh sorry, seven years, but the five year data was very similar. Uh they had, you know, uh 325 patients also, they had better range of motion with the newer generation device uh compared to the control group. Uh at uh five years, you can see there's been a steady decline in the prodi group over that time period. Um And uh and they think that some of that has to do with the design of the device. Uh Also the uh there's a difference between the active L that the smallest core size is 8.5 millimeters versus prodi has a, has a 10 millimeter height as the starting point. So you might be distracting the facets a little more and over time, then they develop more facet arthrosis and loss of motion. Uh But for, for all of those reasons, they uh the active L did better. I I think this is a very interesting uh subgroup analysis uh about adjacent segment disease. Uh because there were so many patients in the prodi group that lost motion over that five year period, they were able to look at, you know, what was the rate of adjacent segment disease in the that group that lost motion. So they had patients that had no motion, one degree, two degree, three degrees all the way up to the normal, greater than eight degrees that you want to restore. And there was almost a 1 to 1 correlation with the more motion you had the less adjacent segment degeneration there was on uh X rays after five years. Uh So this, you know, I think very compelling data that uh preservation of motion is clearly linked to uh you know, preventing adjacent segment degeneration. And uh and you can see it five years um when you preserve the motion uh better like in the active L group, uh Most of those patients had just the natural history of adjacent sandwich degeneration about 8%. Whereas the pro group where they lost a fair amount of motion, it was up to 19%. And then the overall, when you look at the arthroplasty as a whole, control and val there was about 10%. So, um and then seven year uh results uh uh continue to demonstrate the similar findings. Uh This paper actually won the top paper for 2022 and the uh uh in that journal. Um but the active L had better range of motion at seven years than the prodi did was significant. And then still patients uh uh had less sight uh adverse reactions as well as uh uh significant reduction in back and leg pain. Uh At the seven year time point compared to the control group. And then most of them, uh actually all of them were narcotic free at the seven year time point as well. Uh which is a big difference from their starting 0.7 years prior. Um, and, and 95% of the active l patients remain free of any secondary surgery, uh adjacent segment surgery. And then the question that a lot of people wonder about device, you know, will it fail? Do I have to revise this revision is a nightmare? So I don't want to do it. But if you look historically and this is worldwide data of ex plan cases because they have to be reported to the FDA. And there's ongoing safety surveillance being performed. It's only 0.04% explan rate. So it's very low and I, I think it's very different than the share experience. And uh most of that has to do with the design of the, of the device. Um So, you know, having that Semicon train and uh uh mobile core, I think, make a big difference. So I'm gonna shift gears completely now. Uh So that that surgery is very good for um younger patients and uh maintaining motion. It's an anterior approach, uh doesn't work well when the facets are, are damaged. Uh But uh you know, the the question is, are there options for older patients? And uh you know what happens when the facets are diseased and you have stenosis, can we still offer them motion preservation? And I think uh uh we can. And now this year a newer device was approved, uh I was part of the ID study for that device and um uh its history is about 20 years old, but it's basically uh facet arthroplasty. So now for older people, uh more pathology in the, in the lumbar spine, there's uh there is an option of uh uh facet replacement. Uh The first device was called tops. And that's the one that is currently uh approved and designed, but it was a completely intact uh device and uh implanted uh into pedicle screws. Um and they started an ID study, but then there are some financial issues with the company. Uh so it didn't continue. And then the, the two other devices which were kind of in c two construction of this uh arthroplasty device. Uh Both companies ran out of money during their ID study. So those uh devices never came to market and probably never will. But in 2011, another company acquired Tops and was using it O US uh had great data outside the US. And uh uh and then brought it to the US for an ID study starting in 2017. It was completed, got approved uh just this in 2023 August and uh and now it was being used uh readily, but um you know that it's a fairly straightforward system to use. The technique is almost identical to what we do for uh a posterior lumbar fusion like a tiff or pl uh but you're not going to put in an inner body cage. So it's a little less in, in that way. And uh uh if, if you needed a revision in the future, it's very easy to remove the device place in uh rods and bone graft material. And then, uh and that would be, you know, uh a revision strategy if, if ever needed. Uh But uh but it's a fairly durable device and you can see uh uh and the cartoon schematically how it works. It allows for flexion extension, lateral bending and even rotational motion that the, the interior device doesn't uh doesn't allow for as well. Um And they, the ID study, well, technique wise, you can see this is just a video showing uh the technique uh and, and for the study, it was specifically patients with grade one spondylolisthesis and stenosis. And I'll go into the details of that in a moment, but just showing you the, the surgery which is very uh typical laminectomy, uh full facetectomies, placement of screws and then you're trialing the device. So this is a trial to s it comes in three different sizes depending on the patient's anatomy. And um and then they uh prepare it on the back table. They have to uh inject a little bit of saline into that core to help with the, the motion. Uh And then it, it gets implanted as one device. It's a little bit bulky uh to go in. But uh it's more the, the side to side. Uh um, but the, the prominence, it's no higher than the patient's normal spinous process. So it's uh uh it's not something that they, they can feel uh much, but it uh uh it functions very well to preserve motion. And, um and in their ID study, um is also a device that can only be used for single level. And you can imagine how it's designed. You can't stack them there. It's really just one level disease that you can treat. It's not because of the angles and size. It's not amenable to L five S one, but uh L two to L five are the levels that can be treated. Um And in this study, we had patients that were aged 35 all the way up to 80 because it's uh treating pathology that is present in older people and they tolerate this. Uh And similarly, you couldn't have a mobile spondylosis, but uh grade one that did not move much um is uh is an ideal. Um And then there are 37 centers. Uh One of those was Georgetown, um good mixture of neurosurgeons, uh some orthopedic surgeons as well, but two thirds were uh uh neurosurgeons in this group and some academics, some multispecialty groups. Um The demographics, uh what you would expect, uh, average age was, uh uh in the mid sixties, uh, you know, pretty equal between males and females. It was predominantly Caucasian uh group and the majority of treated levels were L 45, which you would expect because that's where we tend to see the most number of spondylolisthesis uh as well. Um And then their composite success was, was a very stringent one. So they, uh they had six measures of what they considered clinical success in this study. And there was no reoperations or lumbar injections following surgery, a reduction in odi of greater than 15 points. Uh no neurological changes in the post op of window and then no major adverse events. And uh and they looked at fusion status obviously for the control group, which was the tiff. So it was two thirds to the tops device and one third uh fusion tiff. And, you know, they saw a really drastic difference between uh the tops and the fusion group. So the overall clinical success was 77% in the tops group and only 24% in the fusion group which uh even the FDA was a little surprised by that. Uh So they, they actually made the company go back and remove the uh the no fusion criteria from uh from that. So when you looked at the subgroup analysis, you know, they were, they were better in most things. Uh they were only equal in the no major, uh, adverse events after surgery. Uh, but, uh, tops was better in almost every category, uh, of the six other than the fusion status because that was, you know, not something that you look for. I mean, they look for fusion in tops, you know, if the spine spontaneously did, but they, you know, you don't expect it in a motion preservation, uh, surgery. Uh, so they, the FDA said that cat and let's look at the outcomes and, and see the difference. But even in that setting, it was still statistically better for tops. So still 20 plus points, greater success with the tops compared to the Tiff group. Um And then when you looked at the reported outcomes, uh a lot of the even in the early time points following surgery, patients did better with tops than fusion. So you look at the six and 36 week and three month time points, they were, you know, much lower than the fusion group. Uh And, and then it was sustained, it was better uh for each category and each time point, uh and same with uh VA S back scores, uh which, you know, says something because you'd expect uh patients to be very similar in that early post-operative window that you're just recovering from muscle retraction, you know, incisional pain that but uh it says something that, uh you know, our fusion patients are really adjusting to being stiffer and uh it's not necessarily an easy adjustment. Uh But when you preserve motion, uh they tend to have a little less pain and in back and uh overall uh functionality um and similar, uh they had a little better, you know, reduction in leg pain as well. Um And then, uh the subsequent surgical interventions, uh the biggest take home, you know, there were, you know, similar situations, there were some wound uh issues. Uh They were mostly in the tops group, there was a seroma hematoma and then one infection that required surgery, a couple of retained drains, uh you know, but uh and then some screw loosening uh that happened in both groups uh that required another surgery. Uh But the, you know, the, the the category to look at most closely is the adjacent segment degeneration and who required surgery. So there were, you know, 3% of the fusion group that uh uh needed surgery for adjacent segment issues and that uh two year follow up period versus zero obviously in the tops for adjacent segment uh issues. So, and overall, there was uh you know, a difference because of uh predominantly that. And then uh this is radiographically, the device does preserve motion. So when you look at uh motion at one year, two years for the tops device versus uh the fusion, they're preserving uh lateral bending, they're preserving flexion extension motion. And uh this is angular motion in both directions um as well as the uh uh translation because the, uh, there was translational motion. All these patients had uh spondylolisthesis, but it didn't get worse, uh, with the, uh, with the tops surgery. So they, they maintained uh, the, uh small slip that they had preoperatively. Um But, uh, but I think with facet replacement, it's a good solution for older patients that have severe stenosis or spondylosis. Um, or uh obviously the, the, the most, uh or I should say the least invasive uh efficacious way of preserving motion. And, and I would do this prior to placing at tops is just doing a mentally invasive laminectomy in the setting of a spondylosis. Uh So, you know, if you can do that prior to doing tops, I think that's reasonable, but some people just have such severe facet pathology that they would be better candidate for tops than just doing an mis laminectomy or, or if there's a significant degree of back pain that goes along with the uh with the ridiculous stenosis component I would consider tops over just Ami S laminectomy. Um But the device is durable. You don't get screw loosening the explant rate for this is extremely low. It's less than 1%. Uh and they have uh greater than 12 year follow up in Europe and in Israel, that shows great durability of the device for that time period. And uh and, and from the data we got at the in the ID study, there is clear superiority over fusion with the tops device in this setting. So I think this adds, you know, another tool in our uh in our Armamentarium for treating grade one spon the but also maintaining motion. And many patients will ask, you know, II I want to maintain motion. I don't want to fuse my spine and get this domino effect. And for older patients, I really didn't have much to offer them other than a minimally invasive laminectomy. Um but not everybody is a candidate for that. And, you know, for those patients that also have severe foraminal stenosis as well as central stenosis balsis. I would always tell them, you know, fusion is your answer. But now I think we have uh tops which is a, which is a good alternative. Um um So with that, I would uh thank you for your time.