Endoscopic Treatment of Craniosynostosis: Pediatric Endoscopic Neurosurgery 2018

My pleasure to introduce Mark Proctor from Boston Children's Hospital who will be talking about the endoscopic use in craniosynostosis, which I think all of us who do this kind of surgery have, have seen that revolution in, in the surgical approach from being a very morbid, uh, large open surgeries to slowly becoming more and more minimally invasive. Um, uh, Doctor Proctor is gonna, uh, talk about a lot of the, the really great ways in which we can, uh, hasten the process of, of, uh, children's hospital stays. We can, uh, decrease blood loss, we can decrease OR time. Um, a lot of new, uh, new research is coming out on the time under anesthesia, uh, uh, at a younger age, uh, being cumulative. And since pretty much all these kids are infants or uh at least toddlers, um, this becomes very important. So, without further ado, uh, thank you, Doctor Proctor, for joining us. Uh, we're all looking forward to your talk. Mark, I'm gonna remind you, since, uh, again, it is interactive and and I expect a lot of questions to be generated from your talk. So, so please try and finish by about 9:25 or so, or 10:25, excuse me. Thank you and welcome. This is a great format. Nice to be here. So I'm gonna talk to you guys about the endoscopic treatment of cranial synostosis and, uh, you know, disclosures to, to make, and I'm just gonna start with a little bit of basic anatomy here. So this is just normal skull anatomy in infancy, and we could see that the skull is made up of about 5 major bones. Separated by several of these growth plates called the sutures here. So, you know, I, I think this is probably basic for most people, but I think it's a useful way to frame out the, the talk and, and what we're trying to do in endoscopic surgery. So 11 thing I always address with patients is why is the skull made up of these, of these five bones? Why are we not like other animals that don't really suffer from synostosis? And, and truly the, the issue in, in humans as opposed to other animals is the, the very rapid growth of the brain in the first year of life. So we are born at a very immature state in our brain development compared to most mammals. We have very rapid growth of that brain in that first year of life. Uh, slows down considerably over the 2nd year of life and past about 2 years of age, it's, the sutures play a very small role in the growth of the skull or the brain, but in those first couple of years, they're quite pertinent. And, uh, so if we think about that and we think about Berkow's law, which is, you know, it's a relatively, um, Primitive way of looking at it, but it actually frames out the problem pretty nicely. It, it defines that skull growth is normally perpendicular to the sutures, and if the bone is closed, then you get growth parallel to the sutures because you get compensatory overgrowth in the other, in the other areas. Uh, synostosis affects about 1 in every 2000 live births with sagittal being by far the most common in about half of the children that we see. Uh, and here are just some, uh, common skull deformities. Again, they're all a little bit over exaggerated for, for illustration purposes, but if you go from the normal skull in the middle, you can imagine, well, what happens if this closes. You get less lateral growth and more AP growth, and here's your saggy synostosis skull. Similarly, here you have myopic, uh, bilateral coronal, you're not getting growth in the AP direction, so it compensates by growing wide and also high. So you get the terricephaly, unilateral coronal, you know, it all sort of fits pretty well. And of course, the deformational plagiocephaly, which is what we see by far most commonly in the, in the clinic. So kids with really normal skull bones that are just influenced by external pressures. So going through some of these uh specifics a, a little bit more, this would be saggy synostosis, right? So this is the patient positioned for surgery, this is the front of the head, back of the head, and whereas normally in almost every, uh, normal skull shape, the back of the head is the widest part of the head. In sagy synostosis, the back of the head is the narrowest part of the head, you get a wide and bossed out frontal region. This is a coronal synostosis, unilateral coronal, so fairly classic. Here it is, a patient that has it on the left with the classic Harlequin eye, which is a plain X-ray finding, um. And then these are the views you'll see on a 3D scan on the patient with the condition on the right, so that suture is closed, they're flat here. There's always this orbital uh dystopia where one orbit on the affected side is higher and shallower, and the nose deviates towards that size, uh, side as well. So the nose always points up to the affected side. This is metopic synostosis, again, a fairly Clear example based on both looking at the child and looking at the CT scan. So this, in the, in this bone, this condition, essentially those two bones are locked together and unable to push out in this, this direction. Uh, and here's a metopic patient. Uh, this is just pre and post and endoscopic, uh, treatment. These are, uh, we'll go through this a little bit more, the laser scans used for the helmeting. And lambdoid synostosis. And just to point out that this is a very rare condition. So we see about 100 new synostosis patients a year at our institution, and in any given year, we'll see on average 1 lambdoid synostosis. So that, and that should be about the percentage. It should be about 1 to 2% of all synostosis cases. And it, this is an easy one to confuse with deformational changes. I think the, the easiest examples to see is that you, you should have sort of an extended mastoid on that, on that side, so your mastoid should be low on that side. So now I really wanna get into the endoscopic treatment, and I, I sort of look at the, the treatment of, uh, endoscopic of synostosis as part of a, part of a cycle that, you know, what was the treatment for many decades, it was strip craniectomy up here at the top of the screen, right? So people would do bi coronal skin incisions, take out a piece of bone, uh, and then. Just, you know, let, let the skull correct itself. Well, why did we ever get to these bigger procedures, these, these, you know, um, relatively as a. Described the introduction relatively sort of morbid procedures. Well, it's because the results of the strip craniectomies, they just weren't great, right? In about a third of the patients, the bones fused together before you really got any correction, and uh this was sort of recognized by Tessier and the whole line of uh craniofacial surgeons, and that's how we got to the cranial vault reconstructions, the frontal orbital advancements. And then in the mid-nineties, uh, David Jimenez and his uh plastic surgery associate, Constance Peroni, they said, you know what, you know, we have new technologies now. We can do these operations endoscopically, so the much smaller incisions, less blood loss, and then we can use some adjuvants like a helmet, uh, that, that was their preferred way, but there's springs, there's distractors, there's all sorts of ways of doing it, uh, to, to get back to strip craniectomies as a, as a A viable alternative. And what I'd like to stress is I really think it is a viable alternative to doing these open operations, as long as you're getting the patients early and you're treating them in a sort of pretty holistic manner where you're, you're both doing the surgery and willing, willing to follow them closely afterwards for the helmeting. So, how do we address these things in our institution? I'd say The current trend, it's, it's, it's a different trend, and you, you'll keep people hearing people say, hey, strip craniectomy, that failed, that doesn't work. And I would say, well, the current operations are sort of philosophically different. So we think of open surgery as a mechanical operation, which we do a lot of, we do, you know, half of our volume here is open surgery. Uh, we take off the bones, we put them in the right place, we fix them in place. I wanna make it clear, that's not a panacea, right? When you take off all these bones and do all these, do all this work, those bones don't grow normally over time. They don't, they don't just, uh, then follow the mature pattern of a, an unaffected skull. So the results you have at the end of surgery aren't necessarily completely predictive of what you're going to have 5 or 10 years later. Endoscopic surgery, I think it was a a release procedure. If I'm gonna do this, I have to rely on the brain to move the bones out over time or I have to use something like springs or distractors. Uh, I do have to use some sort of adjunct to direct the growth because just by opening the bone doesn't mean it's automatically gonna take on that new position. And how did we get there in the first place? It's cause there was a lot of experience using helmets for deformational changes. So I think of this, you know, as I explained it to, to families, conceptually, we're turning the synostosis into a deformational problem. We're, we're opening the bones so that they're malleable. And then we're reshaping it with with the helmet. Interestingly, it's been met with a lot of skepticism in the craniofacial community. I think a lot more so than a lot of the other endoscopic procedures we will be talking about today. And uh this is just a, you know, sort of a brief aside. If we look at when, when scopes first started to become really viable alternatives to open, uh open operations, it was really cholecystectomy, first reported in 1987 by a team in France, and it really met very significant early skepticism. But now, if, if I start to suffer from gallbladder disease, I definitely want to treat it laparoscopically. I don't want some open operation like, like my mom had 50 years ago. And this is some of the early literature on laparoscopic cholecystectomy, which I just find sort of amusing, you know, laparoscopic cholecystectomy, passing fancy or legitimate treatment option. These were the titles of these original articles, laparoscopic cholecystectomy. Let us control the virus. I mean, it was really looked upon early on as some, some sort of rogue procedure that was gonna pass and we were gonna get away from. Laparoscopic cholecystectomy, fantastic. You could just see the incredible sense of irony and skepticism in that treatment option. But then it started to evolve a little bit, right? So laparoscopic cholecystectomy, evolution, not revolution. So really reputable surgeons started to say, hey, this is actually a, a good way to treat this disease. And over time, you see laparoscopic cholecystectomy threat or opportunity, it became clear that laparoscopic cholecystectomy was gonna be a viable treatment option, and you had to figure out how do you fit this into your overall treatment paradigm. And one quote I really like from this article here is only surgeons involved with open cholecystectomy and management of its potential complications should before this procedure. And what I want to stress there is you don't want to start to treat. Cranial synostosis in an endoscopic fashion if you don't really know how to treat cranial synostosis holistically, doing open procedures, etc. Uh, I was involved in the development of these parameters of care for synostosis, which was a big project through the CDC, uh, going from 2010 to 2012, and essentially, endoscopic surgery is considered a very viable treatment option, but it was really stressed. You, you want a very, uh, experienced team to be doing any treatment of synostosis. Uh, so, now I'm gonna start a little bit with technique. Uh, so I'm gonna check my time check here, um. And I wanna start with looking at saggyl synostosis. So this is just sort of normal positioning for a patient with saggyl synostosis. This is very nice head holder. It's just, it's, uh, we, it's called the Doro cause that's a company that makes it, but it, you know, as opposed to pinning the patient, it's a nice way of cupping the ears. Uh, this is, uh, pads that slide apart, lets the tube come out between them, and we initially used the beanbag, but that was very hard, and when you deflate a beanbag. Uh, it becomes a very firm substance. So this was a very nice way of positioning the patient, giving the anesthesiologist good access. And here's just sort of a top-down view of that, uh, same, same patient. This is, you know, how we prep it, and this is the ultimate drape. And, uh, this, this, I will, I will stress that the, the scope nature of this case is, is not as sophisticated as a lot of the things you're gonna hear today. The scope is very good for the lighting, it's good for visualization, but there are people who do the same operation without use of the endoscope. And uh we just use a 0 degree endoscope. We try not to even use our good neurosurgical scopes because We don't want to damage them doing a case that's relatively blunt from its endoscopic perspective. And here I have a couple of minute video that'll sort of take us through a procedure. So here we are just setting up that uh head holder. Positioning the baby there, uh. Just injecting local and you can see, here we are making the incisions. I do a lot of this with the Colorado needle, and I think really meticulous technique is necessary to keep the blood transfusion rates down. So, for saggyl synostosis, we'll make these two incisions, come down, score the periosteum. Do a burr hole at either side that we chat out. And then we'll locally expand it with kerosons, and I'm shooting for about a 2 centimeter gap. So here I've just started the hole on one side. Doing the same thing on the other side. Or I should say not side, but back in front. Uh, in this case, this is the front incision, that's the back incision. And in a minute, we'll switch over to the scope on the list in a minute, we'll switch over to the scope view. So here, once we've started those holes, now we're gonna bring in the scope, and you'll see uh the perspective we have from the, from the scope. So here it is bringing in the scope. We've already started our hole here, and here's the Here's the bone. Here you can see the ridge, that's the ridge of the sagittal suture that's fused together, and we're using the scope to dissect the dura off the under surface of the bone. And we'll generally do that from both directions. Although in this case, I think you'll see we actually here we connected to the other hole. So just coming from the back, we're able to position it. This is now between the scalp and the bone. And again, just another, another look here. This is a ridge of dura, and here's the ridge of bone. And once we've completed that, that separation, then I generally take the scope out to, to use these Tessier bone cutting scissors and uh Complete the strip, and sometimes it'll come out in one large piece, sometimes we, we get two halves, it's sort of, you know, breaks in the middle, um, front to back. So here you'll see us taking out one piece, so that's the posterior portion. And here you'll see us taking out the other piece, which is the uh Anterior portion of bone, and then I just like to line it with gel foam. Uh, some people like to cauterize the edges of the bone with a suction cautery. I think that's also very viable, um. And then we just close it up with absorbable sutures, and that's the, that's the procedure. The general duration is, is approximately 30 minutes. Uh, here you can see this is a different case. Here, the bone came out in one piece, you can see sort of our kerosene marks from the back and kerosene marks from the front, and then we just take out the strip. Uh, with regard to how wide of a strip, again, we do about 2 centimeters. There's a recent study that just came out from both a combined study from Hopkins and DC where one was taking out 6 centimeter strips and one was taking out 2 centimeter strips. Another study from Saint Louis showing that, and everyone sort of come to the same conclusion that the narrow strip is just as effective as a wide strip. So most centers have now gone to a narrow strip with no barrel staves on the side. Uh, we just dress the incisions, uh, independently. This little dressing here is just, I just put on for about 6 hours just to keep a little tampon on over the top of the head, and the patients don't go home with that. And these are the helmets, and, you know, I'm not beholden to any specific helmet maker. If they're, if they're in the Boston area, we'll tend to use the orthotist here at the hospital, but I've got patients that, uh. Get helmeting really done all over the world. Uh, so as long as you have close communication with your orthotist, I think this is a very viable way of doing it. And the ortho the orthosis basically just lets you grow out into the available areas, right? You can use springs or distractors. The only thing I'd say is the helmet lets you adjust in real time, right? If you're, let's say, the top of the head is getting a little flat, you want a little bit more rounding, you can adjust the helmet, or a springer distractor, you can't do that with. And these are just different versions of helmets. This is a child with bilateral coronal, metopic, and sagittal. And these are the laser scans that just show you those adjustments over time. So here is immediately after surgery, and this is a six-month scan. So it, it clearly leads to pretty effective changes in the head shape, sustained changes in the cranial index over time, and, and I could tell you it's been compared now by multiple groups, very similar, uh, results from a cranial index perspective to the open operation. Head growth is very good and sustained over time. Again, just another laser scan. These are the scans used to make the helmets. We're not doing anything outside of ordinary care here. Unilateral coronal, I'm not gonna go through in any detail, but just to show you some, some classic cases here, right? So here, here you go, classic left coronal synostosis, the orbit's higher here, nose is deviated, uh, the topic because this is 1 year's, uh, treatment, the topic normally closes over time, but here you could see what we call neo suture formation. It's almost like the patient never had a few suture here. The orbits are nearly level at this point. The nose is straight. Um, we've done a lot of studies looking at the 3D dimensions of the face in these kids. So we, we have 3D photogrammetry that we do on all of our patients, uh, 6 months, 1 year, and then every year. And what we found is that the, the actual facial asymmetry, um, Improved significantly more in this endoscopic group than in the frontal orbital group, and we think this is just the early release. We can tell you we had similar findings in the astigmatism where it got much better with the open sur uh the endoscopic surgery compared to the open surgery. What this is, these were our 1st 100 consecutive cases, so no case was left out here. Uh, it was for all different types of synostosis. So mean surgical time was 48 minutes, estimated blood loss was 23 mLs, 8 transfusions in that 1st 100 patients, and we found that the risk factor was the weight. So if they were under 5 kg, it was a much higher risk. So now we really wait till over 5 kg for all of our patients, and transfusion rates are down to about 3%. And it was a median hospital stay one day. Cost, this was the first cost study that came out from our center. Um, and what we found was the cost of treating this endoscopically is 40% of the open operation. There's now two other really good studies, one from Saint Louis and a third study out from the Midwest in the United States, showing the same results. Cost is always about 40% in the endoscopic. And I can tell you in our study, we include every cost, all hospital costs, the home costs. We, we included the gas mileage for the patient. And families getting to and from the orthoist, so it's a pretty comprehensive study, so, um. The interesting story behind this is our new plastic surgeon, when he arrived, thought endoscopic treatment would be more expensive, so he, he conducted the study and was very surprised by the outcome. So in my last slide here, you know, what I would say is in experienced centers, whether you're doing it open or endoscopically, in this day and age, you should be very safe procedures. Uh, but I would strongly suggest that In the current paradigm, you should have access to both minimally invasive techniques or open techniques, and if you really want to service the patients. Needs completely, you wanna be able to do this endoscopically and have the whole, you know, soup to nuts of the being able to perform the surgery, you know, the being able to do the neuropsych testing and follow up and looking at the, you know, having a good orthotist, etc. available for you. And I, I think generally the outcome should be excellent regardless of your technique. Thank you very much. Thank you, Doctor Proctor. That was, that was great. We have some great questions coming from the audience. If I, if you don't mind, I'll share some of these questions with you. Um, the, the first question is about the heat emission from the scope. Uh, it was a good question because you were showing the dissection using the scope sometimes for, uh, pulling the superior sagittal sinus off of the, uh, overlying skull. The question is whether you've ever seen or do you know of, uh, heat, um, heat emissions causing any damage. Uh, I, I am not aware of that. I would say that the, the exposure of the scope to the door in any one location is very brief. Uh, I don't, I don't usually use the scope at 100%, uh, the light lighting source at 100%. We're usually, you know, more like 70 to 75%, but it's a very brief exposure that that whole dissection for saggy synostosis case is gonna take you 20 or 30 seconds on average. So I haven't seen that. I think in, in my experience, it seems to generate less heat than say the drill would, uh, but we have certainly haven't seen any injury from it. It's wonderful. Um, another question came up, uh, you might be able to answer in, in a couple of different ways is the maximum age, uh, that you would recommend or, or have seen for endoscopic surgery. And I know, obviously some of this depends on, um, how thick the skull is and how big a child is. Uh, a big 3 month old might be out of range, whereas a small 6 month old might still be in range. How would you, how do you go about picking that age group? Sure, well, I, I think if you, if you think about the growth curve I showed early on, I mean that really gives you your window for when the surgery is gonna be helpful. So if, if you're using a helmet, which means you're, you're relying on that brain growth. I would say your ideal age is about 3 months. Uh, so if I'm seeing a patient the day they're born, what I tell the family is I'd like to do the surgery about 10 to 12 weeks of age. Uh, if for some reason they are markedly below that 5 kg mark, we may push it out a little bit. Uh, but 10 to 12 weeks is, is the sort of ideal age that we're, we're aiming towards. Now, what happens if you see a patient, they're coming to you for the first time and they're 4 months? Uh, or 5 months, or, you know, you're getting out towards 6 months. So I'd say that the oldest I've ever done, which was a mild sagile synostosis, was, uh, 7 months of age. Um, I think the result was reasonable. The the parents were both physicians, they were really quite, uh. Quite, uh, committed to doing it endoscopically and, uh, do I think you get, you can get as much correction? I, I don't because you're, you're just that much further along in your head growth curve, uh, but if you're, if you're starting with someone with say a cranial index of 0.62, which is quite low, normal being about 0.75 to 0.8, and you're starting out at 6 months of age, I don't think you're gonna get a very good correction, and I wouldn't offer it. But if their cranial index is starting at 0.7 or 0.72. Then I think it's reasonable to push the age out a little bit longer till, you know, maybe out to 5 or 6 months, but I, I would be very reluctant to go past 6 months. I'm gonna jump in here, Mark. Thanks. That was, that was amazing. Um, you know, and I think that, uh, it, it's, it's highly interesting to revisit this issue of suturectomy, given the context of the, the previous 4 decades in pediatric neurosurgery, and it's, it's really, really me, what, what would be your, uh, counter to the idea that we've done this before and it doesn't work? We hear this a lot. Um, and this has been done before, and what's different about doing a suturectomy today versus in the 1960s when there was a revision rate as high as 20%, right, so it's a, you know, I think I went over this sort of in that, that slide comparing open to endoscopic is, I think if you do this without some sort of adjuvant treatment, you're probably gonna see that similar 20 to 30% suture closes back before you get any significant correction and not having a very effective result. But I do think, and I, you know, again, I didn't, I didn't devise this, it was real, really Dave Jimenez and his and his, uh, plastic surgeon, Doctor Baroni, but The use of some adjuvant, and some groups are choosing springs, some, some are using distractors, we prefer the helmets, but I use springs as well, um. You are directing the growth in a new direction. So if you have a, uh, let me just grab something here from my, my shelf here. So if you have a saggyl synostosis case here, right, and you, you take out the strip, and now you use a helmet to prevent that front to back growth, then you're really promoting that growth out laterally. So it's, it's, it's not just that it, it, this isn't the only direction it can grow, it can still grow in length. Um, but by directing the width, it's very rare to see a refusion before you get your correction, and, you know, and, and we have a paradigm for that, right? We're not trying to stop the AP growth completely. We think that would be bad. That would be a volume reduction procedure, and we don't wanna reduce the volume in the, in the skull. But in the helmet we're shooting for a 2 to 1 growth in width to length during the course of the helmet. So, uh, what that effectively means that if you start with the cranial index in the 0.75 range, after about six months you're gonna be about 0.8. So I, and, and I think you could do that if you, if you know your orthodists well and you work with them closely, you can do that pretty effectively. You can really promote. With over length growth, but allow for both of them to continue to grow. Very important to track your head circumference through all this. You do not wanna stop growth of the head. You don't wanna see a fall off on the growth curve. In fact, if anything, you wanna see it jump up a little bit with the operation. Yeah, thanks for highlighting that the importance of a dynamic interface between the orthotist and the neurosurgeon or a craniofacial surgeon and, and frequent checks of helmet fit and making sure you're getting the, the correction, the fit you want. I think that's vital. Um, a couple of other questions I wanna highlight since we have a couple of minutes. Uh, your, your video is very instructional. Um, instructive. The, uh, preoperative evaluation, I wanna get a couple more elements of that. First, at the time of surgery, can you comment on, uh, the use of a lines, the use of Foley catheters, uh, whether you can make any global statements about that. Some of that has been advocated as being, uh, reducing the overall morbidity in time of surgery. A safe endeavor, something you exercise or not? So when we first started doing these and we now have, uh, we have just over 500 endoscopic cases, so we've evolved a little bit over time. The first cases we treated very much like our open cases, uh, so we would, we, excuse me, we would have two large, uh, well, you know, large for a baby a lines. We don't typically use central lines on any of our patients. We'd have two line, uh, sorry, 22 IVs and a, and an arterial line. Um, in those patients, Foley catheter, I think that was probably variable. I could tell you the standard now is that we, we always do two IVs. I won't, uh, it's very rare occasion if, if they're really struggling to get a second IV, will I consider doing it without a second IV, uh, but no Aline, no Foley catheter, um. You know, honestly, Mark, some of these patients truly could go home the same day. I've never been bold enough to, to do that. We, we always keep them overnight. But, you know, the way insurance markets happen to work around here, a lot of these are not even considered admissions, they're considered 23 hour observations cause that the insurance company then doesn't have to pay the hospitals much money. So they'll, we have a uh an observation area in our, in our recovery room region, so a lot of the patients will just stay there overnight, go home first thing the next morning. Yeah, we're, we're anxiously awaiting your lead to discharge them the same day. The uh, the other question I have is, uh, you know, you show a lot of, uh, CT scans, and I want you to make a comment if you can about the utility as either a preoperative adjunct or diagnostic aid. What, what I have found is I've transitioned into adopting an endoscopic suturectomy and less invasive approach, that you're forced to make the decision somewhat earlier. When the normal evolution of synostosis would manifest on a sequential basis. I find that I'm relying more and more on imaging from a diagnostic aid because I want that question answered sooner. Did you find that, so can you comment on the utility of diagnostic imaging, either plain or uh plain X-rays or CT? So, in, in fact, I think we've probably gone the other way. We're doing less and less imaging. I, I'd say the average saggy synostosis case, it, it tends to be so classic that most of us are gonna be able to do that without imaging, you know, none of these are 100%. And if there's, if there's ever any question, I mean, what I never wanna have happen, well, two things, especially, I never wanna go in and find an open suture where I thought it was closed, right? So if, if, if I have any question, I'm always gonna get some sort of imaging. Uh, the second thing I'd rather not have happen is I told the family that everything was fine and the suture ended up being fused, you know, so. I would say in our experience, probably it's, it's well under 10 to 20% of the patients where you, you're required to get that imaging study to make that distinction. We will, you know, if say for something like Sagy, I'll, I'll consider just an X-ray instead of a CT scan because I think that's pretty clear cut. Uh, unilateral coronal, I think it's, you can almost always diagnose on exam based on nasal deviation, height of the eye, ear position, etc. So that's a, that's actually a rare one. We, we rarely are, uh, recommending scans for unilateral coronal lambdoid, I'd say I would never consider going in surgically in lambdoid without a CT scan. I think that's a very difficult diagnosis to make. Uh, and the other thing we've started to do with some regularity now is ultrasound. So there's much more literature coming out on ultrasound, being able to show an open versus closed suture without any radiation exposure. Something we have not tried, but I've presented to our radiologists is MRI. So, there are people that are showing the sort of black bone, uh, studies. We have not done at our institution, but I think that's a very potential viable thing to do. Which will show the suture being open or closed as that technique evolves and obviously show the brain in better detail than any of the studies. Yeah, thank you. I, and I think the take home is, uh, imaging is rarely necessary, but certainly if there's any ambiguity, it, it makes all the sense in the world. So, so thanks for addressing that. A couple of questions that came in as we were discussing this, um. Have to do with the the use of the helmet that all would agree that it's a very vital adjunct to the procedure. Decisions about when to discontinue it, uh, is it, uh, based on a timeline that is very standardized at 12 months, or are there parameters that one uses along that continuum to say now's the time to stop. So I think that differs a little bit by suture. So for, for metopic synostosis, what we found as soon as we got to the shape we wanted, there's essentially no regression. So if we, if it took 3 months and we've had kids helmeted for as short as 3 months, we got them out, you know, from, uh, you know, we got them out from this, this shape to, you know, I can't use both hands here, but to a more rounded shape, we would stop, so we could stop as soon as 3 months. For saggy synostosis, there's definitely regression. So let's say, let's say your, your goal is to make them perfect, which would be 0.82 at 2 years of age, cranial index. They will regress, uh. A little bit more up to one year of age and even a little bit between 1 and 2 years of age. So generally what we see between 1 and 2 is that they lose on average 0.02. So if we had got them up as 0.84, they'll settle back to 0.82. Uh, so Our average length of time in the helmet is 7 months from, from surgery. So a sagile child, I'm gonna push closer to a year unless the cranial index has exceeded that 0.82 range, and then I'll, I'll potentially drop off earlier in discussion with the family, like, you know, if they lose a little bit, will you be OK with it, or would you say, damn, I wish I went a little longer. Uh, for uni coronal again, no regression, but almost none of them are perfect at a year, so we almost always go to a year for unic coronal. I will say for Sajel, some people have pushed that out to 18 months like Jimenez will standardly now do 18 months. I just think the loss between 1 and 2 years is so small that the value of the helmet is very small. Great. Thanks for addressing those questions. Another question that came up was in regard to the amount of bone removal in a coronal versus a sagittal. Do you have any comments on the amount of bone you removed? Uh, for coronal, I, I also will remove about 1 to 2 centimeters, so it's pretty similar amount. I'd, I'd say most people I know doing this operation, that's fairly standard, like they were always only doing about 1 or 2 centimeters for coronal, which changes the reduction in the amount of bone in the, uh, in the saggit. All right, thanks, Doctor. Yeah, it's fantastic. Thank you. Thank you very much.