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Primer on Pediatric Spinal Deformities: Idiopathic and Congenital Scoliosis

Andrew Jea and Jean Pierre Mobasser

December 10, 2016

Transcript

- Good afternoon, we're doing another session of the AANS Operative Grand Rounds, and we are talking about spine surgery here today. I'm Jean-Pierre Mobasser. I'm one of the complex and minimally invasive spine surgeons with Goodman Campbell Brain and Spine and Indiana University. And today, we have Andrew Jea, who is the chief of pediatric neurosurgery here at Riley Hospital in Indiana University, also with Goodman Campbell Brain and Spine. Good afternoon, Andrew.

- Good afternoon, Jean-Pierre. It's great to be here.

- Thank you for joining us today. We have an interesting topic on spinal deformities, and obviously, this is geared towards the pediatric population.

- Yes, we're gonna be talking about different types of scoliosis that you see in the pediatric population, idiopathic scoliosis, congenital scoliosis, and neuromuscular scoliosis.

- We're gonna probably split this up into two sessions just because of the length and breadth of the topic here. So why don't we get through about 45 minutes to a natural stopping point, and then, we'll start another session at another time.

- That sounds good.

- Okay, why don't you go ahead and get us started?

- Sure, you know, first of all, I apologize for the slide background. This is when I was at Texas Children's Hospital in Baylor, obviously, I'm here at Indiana University, in Riley now. So this is directed at the house staff meant as a primer to pediatric spinal deformities.

- Yeah, I would also say that it's probably directed beyond just residents and house staff. I think, this is become a bigger and bigger topic for even adult surgeons and looking at sagittal balance and deformity even in degenerative spine.

- Perfect, good point. So this is what we'll eventually cover probably in a couple of parts for this talk. Scoliosis, different types of sagittal imbalance, as well as spondylolysis and spondylolisthesis. So just to get some definitions out of the way, we classify a curve as scoliosis if it's greater than 10 degrees, less than 10 degrees, we don't even call it scoliosis. There's different reasons for scoliotic curves. One is a functional reason, something such as leg length discrepancy or a disc herniation which is causing pain and causing a patient to splint to one side. And then there's the structural scoliotic curves, which is what we deal with most often.

- So Andrew, if a parent has a kid that has a eight-degree curve, and they see the x-rays and they're concerned, and their question is, "Do we have to worry about this as they grow up? Does this degree of curve mean anything to their future development of a scoliosis?"

- So there's a couple of things that you would need to look at at eight degrees, even though we don't call it scoliosis. So if there are any red flags in the patient's history or exam that we can tease out how old the patient is. So these are things that we would look at with the patient in clinic, but if it's an older child near skeletal maturity, no other red flags, again, which we'll list a little bit later in a couple of slides. I would tell the parents not to worry about an eight-degree curve or curvature less than 10 degrees. So this is an example of a type of functional scoliosis, due to leg length discrepancy. The important thing to see here is that when the patient's standing, you see an obvious curvature of the spine, but when you ask them to change positions and sit down, that curvature goes away, So, structural scoliosis, something that persists despite position, or if there's a history of a progression, or if it's associated with a rib hump deformity. And this is an example of a structural scoliosis. As you ask this child to change positions from sitting to standing, no change. If you ask them to do an Adam's bend forward test, you might likely see an accentuation of a thoracic rib hump deformity. And this is the Adam's bend forward test. And again, another example of the Adam's bend forward test, and in fact, even with bending x-rays, you're trying to overcome the curve and you're unable to.

- So Andrew, when we deal with adults, a lot of times we have to get lateral bending x-rays to see if it's a fixed curve, how much mobility there is. It helps us in planning for surgical procedures. With children, my impression is, a lot of them are more mobile. Is that less necessary of a test?

- I personally don't get any bending films at all pre-op. I think, it's an option. If you talk with a lot of our orthopedic colleagues, they like to get bending films precisely for that reason, for preoperative planning, to plan where they would do osteotomies to loosen that curve to get as best correction as possible. But like you, Jean-Pierre, I don't think it's absolutely necessary because I think that we can get a pretty good correction of the curvature even looking at static x-rays. I think, we know where the apex is, and I think we already know where we're gonna be doing our osteotomies to loosen things up in the spine.

- So Andrew, obviously, orthopedic spine surgeons really have a headstart on us neurosurgeons when it comes to deformity in the pediatric population, but the neurosurgeon's involvement and experience is growing exponentially each year that goes on. Do you feel we're at a point where we have something to teach or offer the orthopedic surgeons, or are we still learning from them more so than them from us?

- No, I think, we're building on our adult spine experience. I think, as residents go through training and neurosurgery residents, as they come out of residency, very comfortable in taking care of spine cases, even the most complex of spine cases, including instrumentation, three-column osteotomies. I think, it's just a natural area that neurosurgery is gonna expand to. I think that pediatric spine deformity, is probably the last frontier that really separates orthopedic surgery from neurosurgery. And again, I think, it's just a natural course of where neurosurgery is going. And I think, more interesting question, I'd like to get your viewpoint on this, Jean-Pierre, is, is it enough after finishing residency to do complex spine surgeries, whether they're adult or pediatric cases?

- Yeah, I would tell you that my experience has been over the past 13 years of teaching and training residents, that residents today are getting a better training in deformity surgery than we were 15 years ago. And obviously, there's large variations from program to program, but I do think that they are coming out well-equipped to handle complex spine issues.

- Yeah, that's been my impression as well, saying that though I do think that there's a lot to be gained by interacting with our orthopedic colleagues and not competing with them. I think, there is a lot of room to function collaboratively. I think, one greater range which I would encourage residents, fellows, young faculty to get involved with is the Scoliosis Research Society, which traditionally, has been an orthopedic professional society. But recently, there has been an influx of neurosurgeons into the society. And I think that they also recognize the benefits of partnership with neurosurgery. I think, they get to see things through a different perspective as well. So moving on with our presentation. So these are the different types of scoliosis that we typically deal with. I think, you divide pediatric scoliosis into three different types, idiopathic, congenital, and neuromuscular. Idiopathic is by far the most common type of scoliosis. And that can be broken down into infantile, juvenile, and adolescent. Nowadays, pediatric spine surgeons, group infantile and juvenile into early onset scoliosis, which again, we'll briefly touch on later on in the presentation. Congenital scoliosis is a very interesting type of scoliosis that deals with bony abnormalities and problems with formation and segmentation of the spinal column to give scoliosis, which again, we'll briefly touch on. Neuromuscular scoliosis is where I see neurosurgeons, kind of naturally fitting in into management of pediatric patients with spinal deformities. These are patients that we see anyway, the myelomeningocele patients, the cerebral palsy patients, the spinal muscular atrophy types of patients, the muscular dystrophy types of patients. So probably, in part two, will spend a little more time dedicated just to neuromuscular scoliosis.

- Andrew, do you think that with the congenital bony anomalies that we see, that you're more likely to also see a pelvic issue or a leg length discrepancy associated with those?

- Yeah, absolutely. I think, that when you see a congenital scoliosis, you're worried about some sort of systemic insult, during development and more extensive workup needs to be done. So I think that not only do you need to worry about disorders of the pelvis or extremities, I think, you also need to work up the heart, the kidneys, the GI system, the central nervous system, and to image the spinal cord as well.

- Andrew, are you personally, measuring the children's leg lengths when they come to clinic with a scope? Can somebody else do that for you?

- No, I'm measuring the lengths of the legs in kids that come in for evaluation of scoliosis. I think, it's a very important part of the exam. How I do it is, I lay the patient down on the examining table in a supine position, and then feel for the ASIS, and measure it down to the medial malleolus. And I don't do that on both sides. Usually, for a discrepancy of less than two centimeters, it's clinically insignificant. You don't need to do anything with that. If it's greater than two centimeters, they may need further evaluation by orthopedics and may need an orthotic, like a heel lift to deal with that, like discrepancy. But I think it's important that you do the measurements just like measurements in other things in pediatric neurosurgery, like head circumference. I think, it's very operator-dependent, and I think, it's better for one person to kind of consistently get measurements. So as mentioned, idiopathic scoliosis, the most common form of scoliosis, infantile, juvenile, adolescent. Infantile and juvenile grouped into early onset scoliosis.

- Andrew, let me ask you a question about that. When we say there are the young, the infant and juvenile, than the adolescent, are you saying that the adolescent children are people who did not have any scoliosis at a younger age and it developed with puberty or are these sometimes people that may not have been recognized early enough?

- Yeah, not a good point, Jean-Pierre. You know, I think, assuming that it's not a misdiagnosis, the label's infantile, juvenile and adolescent refer to the age when the scoliosis is diagnosed. Of course, you know, I can imagine situations where there was a juvenile scoliosis, like, probably wasn't addressed, until the patient was a teenager. But in that case, if you know that there was onset earlier on in life, you'd probably call it a juvenile idiopathic scoliosis, rather than adolescent idiopathic scoliosis.

- Yep, I'm just sort of wondering out loud that if a child has a perfectly straight spine, is a six, seven or eight year old, and an AP view and a normal lumbar lordosis, what are the chances that that person's got to develop a significant adolescent scoliosis?

- Probably, very low. But it happens, that's what the definition of adolescent idiopathic scoliosis is, is that around the time of puberty, all of a sudden there's a curve that develops. The etiology for why that happens or the path of mechanism to why that happens, no one knows if there's a genetic reason and environmental reason, a lot of research is being thrown at that. But the answer to your question, Jean-Pierre, is we don't know at this point, why that happens or what the risk is for any child to develop adolescent idiopathic scoliosis, when up to that point, they do perfectly normal. One thing to point out is that infantile scoliosis has a very good natural history. Many of those cases self-resolve over time, and usually nothing needs to be done about that except for observation. So a little bit more about adolescent idiopathic scoliosis. Which of the three is the more common of the idiopathic scoliotic forms? It usually occurs around the time of puberty and the etiology, again, is unknown. There's some tests that have been developed to predict once you're diagnosed with adolescent idiopathic scoliosis, what your chances of progression are. Some of you may have heard of the ScoliScore, which basically takes DNA samples from the mouth to try to make that prediction based on a series of genes, but it's not 100%. And it's still rather than experimental. Usually, adolescent idiopathic scoliosis, is a cosmetic problem. There's usually no functional implications to it like pain or neurologic deficits. And there's usually no systemic effects like you would get with neuromuscular scoliosis, such as this curve being so bad that it causes restricted lung disease. And then right heart failure usually does not happen with adolescent idiopathic scoliosis. These are usually normal, otherwise normal, healthy teenagers. Some of the things that you may look for on physical exam, you look for a trunk shift. You look for a shoulder asymmetry, and this is something that may not be comfortable doing in the exam room, but it's very useful to have the patient at this row, so you can get a good look at the contour on the shoulders and back both from a coronal view and a sagittal view.

- I know this is a slight step backwards, but obviously, if you're having adolescents undressed, do you have your nurse practitioner in the room with you, or is the child's parents good enough to have in the room in doing that?

- No, I would have a chaperone, either a nurse practitioner or a nurse that's in clinic. I would not rely on just a parent being in the room to act as a chaperone. So other things you would look for on physical examination, pelvic tilt or pelvic obliquity, and rib hump deformity, especially, on Adam's bend forward testing. And that really brings out a rotational aspect of the scoliosis and will accentuate the rib hump deformity. And there's usually not a kyphotic component, associated with it. If you do see a kyphotic component, that's a red flag. That's not your typical AIS, adolescent idiopathic scoliosis curve. There are some examples. So here's shoulder imbalance. Here is a truncal shift. Here's a rib hump deformity on Adam's bend forward testing. And you'll see a lack of a kyphotic deformity when looking at the patient from a sagittal profile.

- So obviously, these are some pretty, significant deformities for a child. And you imagine an adolescent girl, who does not wanna have this sort of problem, how often are you doing these surgeries because of that social anxiety and phobia that's developed with the curve like this?

- Yeah, Jean-Pierre, this is a cosmetic surgery. And kids with neuromuscular scoliosis, the curves are usually more severe. There's actually a functional component to it, a restrictive lung disease, right heart failure, which is life-threatening. In adolescent idiopathic scoliosis, you're usually doing surgery for cosmetic reasons. And I'm not saying that that's not a good reason, that's a very good reason.

- Yeah, would you say, is there a certain age you try and wait to a child to get to in their skeletal development, before you would do the operation?

- Yeah, I think, you know, you don't wanna affect the final height by doing the surgery too early. Usually, the onset of menarche signals that there's probably another two years of growth remaining, which isn't a lot. So I think that once they're in that second growth spurt, kind of on the upswing, I think that that's the right time to do surgery. There's other radiographic markers that you can look at for evidence of skeletal maturity. I think, the most common one used, and one I use is the research sign, is the ossification of the iliac crest. And a Risser five is a child that's skeletally immature. So I think that anywhere from a Risser three upward, is probably a good time to do scoliosis surgery. I'll also say that once you correct the curve, you almost get an immediate gaining in height. So I think what you may lose with the fusion, you gain immediately with correction of the spinal curvature. So I'll counsel patients and families that way too. I'll say that, "You know, yeah, we're taking away growth, but we're not taking away normal growth." So if you're growing sideways, and once we do surgery, you will actually gain a couple of centimeters of height instantaneously.

- What do you think about these growing rods and these attempts that have been made to continue to allow the spine to grow, but sort of try and change the direction of that growth?

- Now, that's a great question. That's actually the subject of many presentations and debates at big spine meetings, like the Scoliosis Research Society. So growing rods are used in early onset scoliosis, such what children with severe enough curves, where they've failed conservative treatment, even braced therapy, and you need to do surgery. But they're too young to do a definitive surgery because you wanna preserve growth. So there's been a number of attempts that fusion with surgeries. One of the more common ones is the use of a single or dual standard growth rod. The disadvantage of that is that every six to nine months, you need to take the child back to surgery to lengthen them, by assigning them to kind of keep up with growth. It's not physiologic at all, it's a lot of surgeries. The rods are usually placed very superficial supramuscular, so above the fascia, the paraspinous muscles. And you can imagine that there's a lot of mood problems, a lot of Some of the more innovative growing rod constructs, include the Schiller procedure, which involves placing the rods on rails, basically. Having special screws at the last joint and the distal end, performing a limited fusion over the apex. The rods actually don't tighten down to the screws. There are special screw caps that keep the screw head and the rod loose, so that it directs growth over time. The advantage of that is that you may not need to do as many lengthenings, and you may not need to change up the rods as often in six to nine months, you might get a couple of years before you need to take the child back to surgery. Unfortunately, the preliminary data shows that after about two years, the rods no longer grow on their own. Something comes up, the mechanism and things stick together, and some of the more innovative things, are percutaneous lengthening of the rods. So rods that you put in every several months, you percutaneously crank them up. Same disadvantage though, after a couple of years, the mechanism sticks and they now function, and you need to do surgery again. And then VEPTR, which stands for vertically expandable prosthetic titanium rib. So that was meant to deal with respiratory insufficiency and to expand the rib cage that's been extrapolated to use on the spine, either rib to spine, or spine to spine, or spine to pelvis. But that functions a lot, like the standard growing rod constructs where you'd need to take the patient back seriously to the operating room to lengthen them. Same disadvantages, wound problems, wound breakdown, extrusion of the instrumentation in very young children. It's a very difficult a problem to deal with, Jean-Pierre. Like I said, there's no magic panacea for this yet. And actually, that was what I was gonna talk about in early onset scoliosis and later on topic, and go very quickly through that. So the workup for adolescent idiopathic scoliosis, are full spine x-rays. AP and lateral in standing position on upright position, and patient can't stand. It's very important to do this all in one shot. It's not useful to get separate thoracic spine x-rays and then lumbosacral spine x-rays, and then try to put them up side to side and figure out what the sagittal balances or the coral balances are. And we talked about some of the definitions for scoliosis in that 10 degree cutoff. Jean-Pierre, our full spine x-rays, I imagine, that's in use in adults spine also, because of the emphasis on sagittal balance and achieving sagittal balance.

- Yeah, absolutely. I think, that we've had a real change in the past five to 10 years in adult degenerative surgery, not even talking about deformity surgery, and looking and understanding why these one and two level lumbar degenerative cases, are continuing to break down above. And there is a growing belief that looking at the pelvic parameters and the mismatch between lumbar lordosis and pelvic incidence, may explain why we're seeing these subsequent adjacent level breakdowns to some degree.

- And we'll have to say that, and pediatrics, has been very little published about lumbopelvic measurements and parameters. It's just not something that we concentrate on right now, but can following the trend in adult deformity surgery, that's probably gonna be the next research opportunities to look for normative values and then see where we're kind of correlating, where we're off in these lumbopelvic parameters and in outcomes.

- Yeah, the pelvic parameters, have become such an important talking point. It's so many meetings that you really, almost can't attend an adult degenerative conversation, nowadays without becoming a topic of focus.

- So these are just examples of full spine x-rays, and again, you get a very good look at overall coronal and sagittal balance with these full spine x-rays. They're very important in the workup of these patients. Pending x-rays, again, it's plus minus. I personally don't use them. I don't even use them for preoperative evaluation. I think that you get all the information that you need from the static x-rays. These are examples of bending x-rays, and what other spine surgeons are looking for is to see if you're actually able to bend out of the curve, or if it's a fixed curve where you would plan your osteotomies to get the best outcome possible. So, another question that comes up is, so you started brace therapy and you're seeing the patient back in clinic again, should you ask them to be out of their brace or should they be in their brace, when they take their follow-up x-rays? I think that depends on how you wanna follow them. If your initial baseline x-rays were done without the brace, and you should continue to follow them without the brace on. If your initial x-rays that you wanna start following them with, or with the brace on, then you should continue following them with the brace on. I don't have any more

- Not to divert us too much, but bracing is somewhat of a controversial topic. Can you tell me your thoughts on the value of bracing in patients, and have you found a subset where you think it's more valuable than others?

- Absolutely. So going back to our definitions, so less than 10 degrees, not even called a scoliosis. 10 to 20 degrees, you would call it a mild scoliosis, nothing but expecting treatment needs to be done, so close observation. Between 20 and 40 degrees is moderate scoliosis, that's when brace therapy should be initiated. Brace therapy, if it's initiated early enough, and if the patient is compliant, there's actually a possibility, a chance that you can cure a child of their adolescent idiopathic scoliosis, just with brace therapy alone. The controversial topic is how long they need to be in the brace per day. It used to be, the answer was easy. Everyone said, "23 hours a day." You were allowed out of the brace for one hour, just to clean yourself, take a quick shower, and then in the back of the brace. And you would sleep in the brace, you would go to school in the brace. You would try to do your activities in the brace. Not very popular with kids and compliance rates were, they could be better. Then people brought up nocturnal bracing. So wearing bracing only at night, only when they're at home, when they're sleeping. But when they're out and about, when they're at school, you don't need to have it on, so you don't have that stigma of wearing a brace. Then they did a prospective randomized trial looking at different lengths of brace wear during the day to find out which regimen had the best outcome. And what they found was that 18 hours or more brace wear, that gave the best outcome. So I think, we're back to wearing the brace as long as possible, rather than even nocturnal bracing. But I think bracing definitely has its role in treating adolescent idiopathic scoliosis. Again, I think, with a proper brace wear, if it's initiated early enough and the child's compliant, there's a chance that surgery can be avoided. We talked about some various radiographic measures for skeletal maturity. I think, menarche is also very important, the age of menarche. And I think, the best way, the gold standard is probably just looking at a growth curve over time. So as a patient comes to the clinic and gets measured in vertical height as you're following that growth curve, when they start to plateau, that's obviously, when they reached skeletal maturity. Here's an example of Risser sign and this iliac crest apotheosis, calcify over time or ossifying over time. And it starts from lateral and goes medial. So stage one is lateral and stage five is medial. Jean-Pierre, I bet you, this is something you probably don't look at in adult spine surgery at all.

- That would be correct. So here's another cartoon of what the iliac crest apotheosis ossification, looks like over time.

- But it is nice that you showed it, 'cause now, I don't have to pretend like I understand, next time I hear somebody mention it.

- That's funny. So you know, as a neurosurgeon, and this differs from orthopedic surgery, especially, if a child is heading towards surgery, I like to get not only x-rays, but a CT scan for planning as well as an MRI. You know, I think as neurosurgeons, we don't like surprises. On the contrary, our orthopedic colleagues, some of them are very comfortable operating on a child just based on x-rays alone. So I would say, yeah, for neurosurgeon, I think, it's more comfortable, getting some more advanced imaging. And I think it helps you plan out the size of your screws, where you're gonna put screws, where you might use hooks, where you might use bands or wires to supplement your construct. Here, you know, I get an MRI, if we're moving towards surgery, I'll get an MRI earlier if there are red flags. So, what are the red flags? So if the age of onset of scoliosis, is less than 10 years of age, so if it's early onset, if it's in a boy, so I think if a teenage boy gets scoliosis, that's actually a red flag, that usually doesn't happen. And I would say that that child needs further workup with an MRI to make sure that there's nothing else more serious going on. And we can talk about what you might be looking for on the MRI. If there are neurologic deficits, obviously, should be painless, over the deformity. You can get pain over the secondary curves as the spine is trying to compensate, but deformity itself, the structural approach should be painless, or if the curve is atypical in any way. So if you get a sharp curve that gets rapid onset, if there's a significant kyphotic deformity, associated with it, if the curve is to the left, that's probably the softest call of an atypical curve. But those might be relative indications for further workup with an MRI. So what would you see on MRI? So you're looking for a chiari, a syrinx, a tethered spinal cord, and most seriously, something that you're worried about the most is, a tumor, intermediary spinal cord tumor. So, those are the things that you would get an MRI for. Jean-Pierre, you have anything to add to that?

- No, I would agree. I am curious why the atypical curve is to the apex, to the left. What is the thought behind that?

- Yeah, you know, I've looked in the literature many times and I can't get a good sense of what a left-handed curve would predict. And I think that it's not clear. I think most adolescent idiopathic curves, go towards the right. And I think, a minority go towards the left. When I did a study looking at even right-handed curves and getting an MRI of all these patients, about 14% of them still have some sort of abnormality. So you know, I don't know, it's something that's written in the books, and I thought I just mentioned but like I said, I think that that's the softest call of all when you label something atypical in adolescent naturopathic scoliosis. And it used to be, if you were thinking about an anterior approach, so through economy, or if you're planning a thoracoplasty, it'd be important to get pulmonary function test, not pre-op, because you may actually worsen pulmonary function with those aspects of surgery. I think, nowadays, with most people being able to do everything from just a straight postural approach, less important to get pulmonary function tests in adolescent idiopathic scoliosis, much more important part of the workout for neuromuscular sclerosis. So, this is Lenke's classification for adolescent idiopathic scoliosis, types, one through six. I think, that Lenke came up with this classification system to help determine upper instrumented vertebrae and lower instrumented third, but basically, to help take levels of where you would instrument. I think, it's a very nice system. I think, it's very sophisticated. I think, that it can be simplified though. I think, that you can view all types of adolescent idiopathic scoliosis as either being instrumented from T2 to T4 in that region as the upper instrumented vertebra to about L2 to L4 as the lower instrumented vertebra. Again, I think that it's great that you commit this to memory. I think that practically, I think, there's much more straightforward ways of determining instrumented levels. I think, for the house staff and for young faculty, I think, a good rule of thumb is that if you cover 13 or 14 vertebral levels, so from TX to LX, you basically covered that deformity. So, TX to LX, meaning T2 to L2 or T3 to the L3 or T4 to L4. And I think that once you get the lower instrumented level settled, you can kind of determine the upper instrumented level with that rule of thumb. And to determine the lower instrumented level, I don't know if you can, this shows up very well, but you draw the central sacral line, and basically, what it touches the last vertebrae in the lumbar spine, that's your lowest instrumented level. And it's usually between the end vertebra and the neutral vertebra, so it puts you where you wanna be. And based on that, you kind of figure out the upper instrumented level. The caveat is that if there's significant shoulder imbalance and you wanna correct that shoulder imbalance, you would start at T2, that would give you the best chance at correcting that shoulder imbalance. I may have oversimplified things, but that's what's kind of gotten me through a lot of the kind of complex thinking of, you know, how to instrument scoliosis. Jean-Pierre, do you have any pearls to share regarding that even in the adult world?

- Just curious who this Lenke person is, you're talking about.

- That's funny. So, that's my little rule of thumb, and you know, Lenke has been very supportive. He's a orthopedic surgeon. He spent most of his career at Washington University. He's made great contributions to the field, and is very respected in the orthopedic and the spine world. He since moved to New York, I believe, it's Columbia University, and he's very open to train the best qualified candidates, whether they're orthopedic residents or nurse surgical residents. So I would urge young trainees if they're interested in learning more about deformity, I think, that Lenke would be a good resource.

- I suppose, he's okay.

- We talked about this already, Jean-Pierre. Maybe the one thing we didn't talk about is, how often do you need to bring patients back to clinic for follow-up if you're just following them, if it's a mild or moderate curve? So I think, every six to 12 months, I think, is reasonable. I think in the period of slow growth, and this is in general, this is in AIS. But the growth spurts in a child are zero to five years of age. So if you're following a child with a curvature in that age range, you probably wanna bring them back to clinic a little sooner rather than later. And maybe, in the three to six month range, during the period of five to 10 years, it's a period of slowing down growth, and you can actually space it out a little bit. So they're not getting all this radiation from x-rays, and then 10 to 15 years of ages, the second growth spurt, where you probably wanna follow them a little more closely as they finish up group. And we talked about this, for moderate curves, less than 40 degrees, bracing has a role. For greater than 40 degrees, it's a severe deforming and surgery is indicated, And I'm just quickly going through these slides because we covered that in our discussions previously. So here are some examples of some old braces, which looked like medieval torture devices. You have the Milwaukee brace, and kids were still able to be active in the Milwaukee brace. Nowadays, we use a derivative of the Boston brace, and you've probably seen them before. It's like a TLSO brace when these thermoplastic TLSO braces, except they're engineered to be de-torsional. So there's cut-outs in the brace and other parts of the brace where it actually pushes on the spine to try to get some correction with the brace wear. And this is severe curves, and here's an example of adolescent idiopathic scoliosis case that we operate on. This was early on in my career, and there's a significant improvement in the curve, but it's not I would say, as your career matures, I think that you become a lot more comfortable with maneuvers and you kind of push the envelope, a little bit to try to get that straight spine. I think, that the philosophy--

- Let me ask you, because this is a point where things may vary a little bit between treatment of an adult deformity, and a child deformity, and that when we're assessing an adult, we're looking for a first level area where you would start or stop something. But I guess with children, there's some compensation going where you know that if you correct the apex, then those levels below can be spared and will level out. And it looks like on this x-ray that those levels at the L2, three, and four areas where there was angulation are now straighter with the curve being corrected above.

- Correct. I think, in this particular case, Jean-Pierre, I think that there were two structural curves here. I think that this goes beyond a compensatory curve up here. So I think that there was a classic curvature, as well as thoracolumbar curvature. So this construct was meant to span both those structural curves. You're right, though, if you're able to determine that the there's a secondary curve or a more minor curve, that corrects itself. You just address the structural curve, and that's the goal of treatment.

- Yeah, I was talking more, if you look at the bottom of your construct where you stopped, it's now below the level on the post topics, right, when it was angled on the pre-op.

- Oh, I see what you mean. Yeah, you're absolutely right. So right, we'd want to try to spare the lumbosacral junction as best as possible. And we certainly don't wanna go into the hip. We don't want to cross the SI joint that has significant implications. And in the ability to walk actually, the SI joined, is very important in smoothing out at the gait cycle and a lot of implications for doing that. So as best as possible, we would like to stop shorter L5-S1. This is an example where an anterior approach or anterior lateral approach is done in a very selective fashion, just to address selectively that the curve, and this is another example of where you were talking about before, Jean-Pierre, that by addressing just the structural curve, and you did that with a very limited fusion, the compensatory curve straightened out by themselves spontaneously. This is another example. And this really is an example of things that were done in the past, which is a Harrington rod construct, which is basically treating scoliosis with distraction. So you put anchors above and below, and you take a lot, and you distract over that to try to get as much correction as possible. So the first real attempt to treat scoliosis with spinal instrumentation goes to Paul Harrington. Another example of our Harrington construct. So again, I'm gonna group infantile and juvenile idiopathic scoliosis, under the early onset scoliosis, as well as the congenital scoliosis, very difficult to treat. This is where you would try a bracing, you'd try casting, and if all that else fails, you would go towards a growing rod construct or fusionless surgery to try to preserve growth. When we talk about all these options for growing rod construct, that should have, nowadays the magic water, the percutaneous magnetic rod. Infantile idiopathic scoliosis, has a very good natural history. A lot of it corrects spontaneously as the child gets older. Congenital scoliosis are a very interesting group of scoliotic deformities. It's a bony abnormality of the spine, a problem with both formation and segmentation. So a segmentation problem would give you a bony bar on one side, which tethers the spine on one side while allowing unopposed growth on the other side of formation problem is what we typically call a hemivertebrae or walk vertebrae or a butterfly vertebrae. And these are some different forms of hemivertebrae. The rule of thumb here is if there is a growth plate associated with it, so if you have a disc space, and you have an end plate or growth plate associated with it, that's something you need to watch very closely. If you have a hemivertebrae that's completely incorporated into the particular bodies above and below, you don't need to worry about that as much. There's very little growth potential for that hemivertebrae. Even for these fully segmented hemivertebrae, the natural history is pretty good. You have time to watch these children and watch them get a little bit older, before you need to intervene. And the older a child gets before you intervene, and do plan a big spinal fusion, the safer than surgery is. Example of probably a hemivertebra, there may be a fusion on the contralateral side. That's actually the worst combination. When you have a hemivertebrae on one side and a bar on the other side, that natural history is very bad that you may need to intervene sooner rather than later. This is natural history, not bad with your one of the types of deformed vertebral bodies, worse when you have a bar. And by far, the worst of all of these different forms, is a bar on one side and a hemivertebra on the other side. We talked about this already, you know, that a congenital scoliosis may herald, or it might just be the tip of the iceberg, and may necessitate further workup to look for systemic abnormalities as well.

- Let me ask you not to sidetrack you at this point, but we are now doing so much neuronavigation interoperatively that we've moved away from preoperative CT scans to reduce radiation, because we found that with navigation, we can access pedicles that were more difficult and worrisome that we needed preoperative planning. Are you using navigation? Has that reduced your need for preoperative CTS?

- I am, I'm using a navigation. Love it, I think it makes a surgery a lot safer. I still get a preoperative CT though, Jean-Pierre, yeah, and I'm one of those people, like, they just don't like surprises. I actually draw a preoperative plan. I have a whiteboard in the operating room and actually draw or sketch out a preoperative plan, even down to based on my review of the preoperative CT, how long the screw should be, what the diameter should be, things like that. So while I use a navigation, I still get a preoperative CT scan. I thought you were gonna hit me on, what about radiation and what about the risk of cancer in the future and all that stuff?

- Well, I think those are important topics. And I do think though, getting your surgery done properly and using the tools that you need to achieve your results is important. We have found in adults over time that navigation has helped us so much that I no longer need or require a preoperative scan. I can figure out what size screw at the time with the probes and the projections, and get an accurate placement. And so, all the things that I'm sure you see as well, but everybody does things differently. And I just think that if that's what you need to do it comfortably, that's certainly within reason.

- So the treatment for congenital scoliosis, just like any other early onset scoliosis, very controversial, it's not one best treatment. Things that have been described are in situ fusion early on. They try to fuse a child in place and try to keep the deformity from getting worse, to do a fusion on one side, to actually create a bar on the convexity and let the concavity grow to catch up with that convexity. And then, most intriguing, a resection of the hemivertebra followed by a short segment fusion. So this has also been looked at in Miami Children's Hospital, very well known pediatric orthopedic surgeon, Dr. Harry Shufflebarger, looked at these three different types. And what he found was, and again, this is not unexpected, but it was just nice to see someone write about that, that as you go from in situ fusion to having vertebral resection and instrumentation, the risks of surgery go up. But also, thankfully, your buck also goes up. So you might actually, be able to get an excellent correction, but again, at the price of high risk. Very quickly, I just kind of give everyone a little taste of a neuromuscular scoliosis. And then I think, we'll end. So neuromuscular scoliosis is, again, something that pediatric neurosurgeons, went across often. We'll probably see them for other reasons, like hydrocephalus and patient having a shunt in or patient in Spina Bifida Clinic or Spasticity Clinic. So patients with cerebral palsy, muscular dystrophies, spinal bifida, not so much poliomyelitis. I think, that's something that's really not seen that much nowadays. A lot of people extrapolate what you see in adolescent idiopathic scoliosis and extrapolate that to neuromuscular scoliosis. I don't think it fits too well. You know, I think that these kids have so many other things to worry about, that I think it would be unfair to call a 40-degree curve, in a child with a neuromuscular disease, a severe curve, and therefore must do to surgery. I think that your threshold to operate is probably a lot higher than you would be in an adolescent idiopathic scoliosis case. If you do do surgery, it's straightforward. There's actually not much planning that goes into neuromuscular scoliosis cases out. You know, I feel bad for saying, and I might be kind of drawing the curtains away from their wizard of Oz and over simplifying things. But in neuromuscular cases, you simply wanna control the entire spine. If you try to do a selective fusion, the child, because they have neuromuscular problems, they're gonna fall apart above or below where your expectation is. So the thinking is, you do a fusion from T2 to the pelvis. And there's not much more discussion other than that. And I think that that's my last slide for now, John-Pierre. And again, this is something we can touch on in the next part of our series, I guess.

- Yeah, I think that was a great session. And I think that was very educational, and a good starting point, so I think we'll end things for today. And then, we will come back and address the other pediatric deformity issues that you mentioned at the beginning of the talk. So thank you, Andrew, for taking the time. I appreciate it, and I will see you at the next session.

- Jean-Piere, thanks very much. Thanks for the invitation. See you at the next session.

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