Well, thanks very much. My name is Dan Schub. I'm here in Baltimore, so not a long trip for me and Charlie, for that matter. I wanted to thank Bob and Justin for the invite, and Joni, as well as Katie, who I just met, for setting everything up in the NNS and the NREF. So this is something that we've been involved with for years, and like Bob said, this is something that maybe, I don't know, in my training was something that was really off the side in terms of deformity. So it's becoming mainstream for all you folks, and if you're coming to courses like this, you've probably already self-selected yourself to say, I'm interested in this, I'm going to learn more. So you're going to learn a lot this weekend, but as Bob said, this is a constant thing that we're all learning. So my job today is coronal deformities, and this is going to dovetail with what Bob already said, and it's going to dovetail with what people are going to say in the future. So if you see repetition, it's probably a good thing, because these fundamentals are good to go over again. Here's my disclosures, which I don't think are relevant to this talk. So here's a patient. This is a young 14-and-a-half-year-old patient, and all the numbers are up there. These are standing scoliosis films, which, as Bob said, are now a must. I mean, I basically get them on every single patient. So someone asked about fusions, and lack thereof, pretty much every single patient gets standing films, because they may have a deformity as time goes on, even if they don't have one now. So you'd like to get a baseline, at least to the very least, on those patients, even if they're not doing an aggressive treatment. But this is a patient that, say, comes to the clinic and has all these numbers, and as a neurosurgeon, I'm putting neurosurgeons on the spot for today. This is not a patient, you know, as a neurosurgeon, often our residents will say things like, well, we need to decompress them, and I'll always say, this patient's not complaining of any leg pain. This patient's not complaining of any neurogenic claudication. This patient's not complaining of any cervical myelopathy. That's not the problem, okay? The patient's actually not complaining of significant pain. Maybe a little bit of pain near that rib hump, right near that thoracolumbar curve, but really this is not their problem, okay? Likewise, they're not complaining of any overt instability. Overt instability in the setting of trauma, overt instability in the setting of tumors, or gradual stability in the setting of a spinal prosthesis. This is a slow curve. So the really question becomes deformity. So you have to change your thinking a little bit when you see people with deformity issues. This is not something that you're going to decompress and fuse, and really the three things we can do as spine surgeons is what? Decompress, stabilize, or realign. And so this is really kind of the third, all right? And this is a picture that you'll probably see multiple times, and this is the goal. No matter what x-rays are done, whether it's a 3D, whether it's a rotational view, this is what you really want to have. You want a balance of the head over the neck, over the hips, over the feet, okay? And the numbers, I'm not a big fan of memorizing numbers, I'm a big fan of memorizing trends, and I always tell patients the absolute is not the important thing, it's the trend. So as you'll see in some of the later talks, is that a lot of these numbers are driven by the nature of the sacral, by the nature of the pelvic incidence, and the way that the sacrum and the pelvis are hooked together upon birth, and become the way you are once you start walking upright. So these numbers are generals, but in general you can have someone with a pelvic incidence of 85, like a lady I saw two days ago, and requires lumbar odosis to be commensurate with that, as you'll learn in the workshop with, I think, Praveen or Justin later on. Since I'm doing coronal, this is just a quick thing about sagittal balance, but here is the coronal idea, okay? So you drop these plumb lines from C7, you try to match it up, the C7 plumb line, you try to match that up with your, basically your central sacral vertical line, which is this CSV. So here's your central sacral vertical line, and here's your plumb line, and these are off. This is a balance issue, okay? And sometimes we call this a trunk shift, when the ribcage is shifted off the pelvis. And this is our scoliosis, or our coronal curve. So these are different issues. You can have a patient, as we saw in the first patient, I'm going to bring you back to that one, who actually, their central sacral vertical line and their C7 plumb line line up. They are in balance, coronally, but they have a big curve. So this patient is off balance. And then these are these vertebrae that we're talking about before, that Bob mentioned. The stable vertebra is when you drop this, or when you raise this line, does it go through the pedicles? Okay, that's a stable vertebra. The neutral vertebra is when you look at it, do the pedicles look at you en face? Are they, is this thing rotated? That's a neutral vertebra. And then the end vertebra are the vertebras at the end of the cob, the longest, let me put my arrow here. The end vertebra, you'd have another end vertebra way up there, so you could argue that the end vertebra may be here, and may be here. Your goal is to draw the biggest angle possible, that's your cob, okay? And here we go, cob angle, the most tilted, neutral, without the rotation, stable, bisected, and the end vertebra are the two bodies at the end, okay? And scoliosis, the term scoliosis really is a coronal malalignment, so we often, the surgeons do this, we often say spinal deformity. Patients don't necessarily like that when I say, yeah, you do have a deformity. And so they're like, I thought I just had scoliosis, I didn't know I was deformed. But they're kind of, you know, we use that term together because scoliosis, sometimes people think of as just a curve in the coronal plane, as opposed to a deformity, say at the lumbosacral junction, or cervical thoracic kyphosis. Those, spinal deformity encompasses all those as an umbrella term, but scoliosis we often think of a coronal issue, and as, in primarily. And really we think about 20 degrees or so. And these are the presentations, anything from complaints of how they look, to the closed mid-fitting weird, to thoracic malalignment, rib cage mechanical pain, and then they can get neurologic issues, or they can progress. And so really the global way to approach these patients for the rest of this talk really is to think of what are the symptoms, what is the patient complaining of, number one. Identify that the alignment is abnormal, and that's by looking at standing films and characterizing the curves. What is the etiology? Because that'll define what you decide to do. And then how is this going to behave over time? Can you get clues to how it's going to behave over time? Yes. The age of the patient, if they're young, will determine significantly, and the scale to maturity, and the curve magnitude, and the type of anomaly. And then is it, as Bob showed you, is it stiff or flexible? Why does that matter? That matters significantly because if you're going to fix this or treat this, technically you want to know if it's going to be flexible, so you put them on the bed and they can move to their rod, or do you have to break them up in some way and release, do some kind of releases. And then finally, what are the goals for the patient, should they even be treated? So you have to first think about, once you've managed to get on those x-rays and ask the patient what's going on, you want to kind of characterize what the deal is. Is it congenital? Idiopathic? Is it neuromuscular? Degenerative? Here's a patient with laminectomies who's slowly breaking down over time. Traumatic, infectious, iatrogenic, or syndromic like this NF patient. Alright, so these patients can have significant scoliosis that's sent to me for a tumor management, and you look at their scans and they have a significant kyphoscoliosis that you cannot ignore in taking out their neurofibroma, for example. Just a brief thing on idiopathic scoliosis, I think Pete is going to talk about the ways to treat this, I just want to talk about this in relation to the coronal issue. Really it's a spinal deformity occurring during growth of childhood or adolescence, and really the big two keys that I take home on these patients, and you can get delved more into these, is two things that are going to impact the curve and the curve progression. How old they are, meaning how skeletal mature they are, and how big the curve is. And you can do this with x-rays and you can do other types of dosimetry testing to look at their bones, and dialysis. And as we know the indications are neurologic compromise in general, but when we see, so when you all take your oral boards for neurosurgery, anyone that's DGEN, anyone that's DGEN is going to be followed for a number of months. That's the answer. Anything that's trauma or tumor or what have you is usually the opposite, you usually want to be, but this is the issue that we do in practice and it's the issue that we feel is a field we should do, so deformity is no different if they have pain and functional debilitation. In terms of deformity severity and progression, you look at children who are growing and if they failed bracing, or if their curves are a certain amount, usually we don't think about things until they are at least above 40 degrees, but usually we think 45 or 50, and if they progress 5 degrees in a year, more than that. And this is a paper that came out in the 1980s which I think really sums it up, at least for me, where you look at basically a plot of two different factors. Riscer grade, which is the scale to maturity, versus the degree of curve. So if you look at this, 0 to 1 means younger, so younger is associated with more curve progression and so is a larger curve to start with. So if you go 0 to 1, you're all the way up to 68% on this group, whereas if you do the opposite where you have smaller curves in older children and Riscer grades 2 to 4, you're really looking at 1.6. So if you look at children and they're older, their curve may not progress if their bone is mature, and if the curve is smaller, and it makes sense. In terms of the fusion surgery, when fusion is considered, the goal is to either correct the curve without negatively impacting global balance, and that's going to be brought up by the sagittal talk, I'm sure, as well as the pelvic issue. So back to this patient, if you drop a C7 plumb line and make that match with your central sacral vertical line, this patient is in balance, okay? So if this patient's curve is going to be changed, you cannot shift them off to the side or forward, which would be even worse, because outcomes are terrible with that. So this is the type of operation that one can do in these patients, which maintains sagittal and coronal alignment. Now, as Bob said, we used to give a talk on this, and I'm just going to touch base on it because it does matter with coronal issues, but we really want to base your learning and base your practice on getting the basic angular measurements. In the old days, they used to classify these by the King classification, where it really was just kind of match it. It's almost like a pathognomonic. If it looks like this, this is how we think we're going to manage it. And then Lenke, with a number of other authors, came along and really tried to break this down based on segments of the spine. And the goal of this Lenke classification, which is a big classification that may seem complicated, is really to define what you're going to fuse and what you can get away with fusing and what you, if you don't, will be a problem. So they broke it down into basically three proximal, a main, and thoracolumbar, so proximal thoracic, main thoracic, and basically said, define those curves and quantify them. And if the curve is big, the biggest curve is a structural, and if the other curve does not bend out or is a certain size, that's also structural. And what does that mean? That means you've got to fuse it. That means you've got to put it in your fusion construct. So here you have all these types, main, double, double major, triple major, and basically this is kind of how they break down, too. You can have one curve in the thoracic, you can have a double thoracic up in the middle, you can have a double major, thoracolumbar, you can have all three are majors. In essence, a triple major means all three have to be fused, and a main thoracic means just that area has to be fused. That was the goal. It gets a little more complicated, they have lumbar modifiers, seeing the nature of the lumbar curve, and they have sagittal modifiers, which is becoming more and more important in the adult deformity field, probably all fields, where if they're positive or not, if they have a kyphosis or not, then you also have to treat that kyphosis. And when you put all these together, you can create basically 42 combinations, or 40, yeah, 42 combinations. So the idea is not so much to memorize this, but just to have some understanding of how to measure the curves, and to think about what you'd have to treat. Okay, that's in the child. And it may leave you confused, but once again, the goal is really to help define your curves on a coronal and sagittal plane. So the keys to the AIS coronal deformity really are, are they mature, how big is it, and then classify it, maintaining balance. Briefly discussion on adult deformity as it relates to the coronal plane. These patients present differently, as Bob said, okay, these are patients who classically have the neurogenic claudication, the radiculopathy, the stenosis, and the low back pain. And they often have in their images more rotatory subluxation, and a lot of things really are based on the lumbar spine, okay, not as much on the thoracic spine. But you can have adult deformity patients who start off with a scoliosis and can progress later on in life. And as I said, they present differently with neurogenic claudication and often balance issues. And when this was originally classified, it really was once again, kind of a color scheme, blue, purple, polka dot, what have you, just describe what you see. And as we've moved on from the EBI classification to the Schwab classification, where now we're starting to get more like the Lenke, where we're describing where the curve is, do we have modifiers in the lumbar, and do we have subluxation modifiers? And this really has peaked in the SRS classification, where it's all kind of together. And you can see it can get very complicated, more so with the sagittal alignment now, where you can have an EBI basically saying, this curve is a 3A, that's all it is, to a Schwab where it gets a little more complicated to this SRS, which is really kind of looking at the location, the magnitude, and the sagittal balance. And more recently, and Bob had mentioned this as well, is if you look at asymptomatic individuals, what we're finding out is that the goal of someone my age is probably not the same goal in terms of parameters as someone who's twice my age. Because as we age, our natural or asymptomatic ranges of these curves probably changes from childhood to adolescence to adulthood and to elderly. So the adult deformity keys in terms of coronal are really, what is a patient complaining of just like the child? Usually these are a little bit different, and they often may require rigid releases, unlike the children, and surgery can be a big deal. We can go from the front with a number of lifts. Something like this, and Charlie will talk about this I think tomorrow or later today in terms of lateral approaches. Okay, these are ways to do it. Segmental posterior manipulation, whether it's from rods, if they're rod contouring and placement, rotational issues. Here's a neuromuscular type where you can take the rods and you can really slide the moment from a classic C-shaped curve. One can compress on the convexity and distract on the concavity. A lot of us don't distract in general because that is often kyphosing, but that can be done. In children or flexible spines, you can do derotation maneuvers, which you really can't do in the adults unless they're completely released at multiple levels. This is something that pediatric deformity surgeons will use a lot. Adults use this less, and this can be done from the back or from the front. And then finally, there's osteotomy techniques where you can take different levels of bone from one side or another and create these asymmetric PSOs or asymmetric osteotomies to help a coronal alignment issue. So in summary, at least from coronal, and you've got to put this all together with the sagittal and with the techniques, is that adolescents and adults have different presentations and coronal issues seem to be bigger in children with AIS. And the treatment obviously depends on the presentation, natural history, and the global alignment. And you have to think about what your goals are in order to not send the patients off balance. Thank you very much.

coronal deformities

spinal surgery

scoliosis

alignment correction

treatment goals