Good morning. I'm going to pick up talking about adolescent idiopathic scoliosis. As Bob mentioned, it's it's a difficult area to break into from a referral standpoint mainly because of the pediatric orthopedic surgeons. I have the good fortune to work at a place where we get along very well with the pediatric orthopedic surgeons and so do a lot of the complex cases together and and have a nice a nice relationship which I think is very been very helpful and very fruitful. So talking about the basics of AIS which I think is important to understand as I mentioned yesterday because of it's because of the principles that we've learned about deformity over over the years from its treatment. Its prevalence if you define it at its minimum level of about a 10 to 20 degree curve is is not low 2 to 3 percent but only about a tenth of those are our curves of a magnitude that end up needing to be treated. It is by definition a disease of the 10 to 18 year old patients and about 9 to 1 ratio of girls to boys in in AIS. There are familial clusters so these are all important elements of the history and evaluation of the patient and typically these curves for reasons that are unknown are right thoracic or a left thoracolumbar lumbar curve and just I think what's been mentioned several times but you know we hang films you know make sure that you look like you know what you're doing when you when you hang deformity films we hang them with left on the left right on the right the opposite of the radiographic orientation and we name the curves based on the convexity. So right thoracic and left thoracolumbar lumbar curves are the are the typical directions of these curves if it's the opposite of that then it probably warrants some evaluation to make sure that there's not an underlying cause. It's rare that AIS causes pain you know there is this whole issue of backpacks and low back pain and adolescence and and there's a like in adults there's a reasonable low-level prevalence of low back pain activity related sort of thing and that's that's probably not related it's probably a true true unrelated situation in a patient with AIS and if there is significant pain in a patient with AIS again it would warrant a further workup to identify the source of it because it's very rare that there is significant pain in these patients and of course there's several treatment options as we as we talked about yesterday observation is is certainly an option bracing and and surgery. The genetics are important there is an increased incidence of scoliosis in first-degree relatives of course particularly female relatives so it's worth taking that history particularly not just a history of ODGF scoliosis but were you treated or was there an aunt in the family or a grandmother mother that her sister that was was treated either with bracing or with surgery because there is a higher incidence. There is an association in increased association in monozygotic twins and they're probably multiple patterns of inheritance of a tendency towards AIS. The natural history again there's a minimal difference in comparing patients with and without AIS in back pain, disability it's not typically a disabling condition. Cardiopulmonary compromise which is usually the first one of the first concerns I get asked about by patients or their parents is extremely rare and only an extremely large untreated curves there's therefore no increase in mortality as a result of scoliosis. This is really the the key or one key aspect of the treatment in adolescents of patients aside from the clinical deformity and that is that if a curve is around this is over this 50 degree tide marker so a skeletal maturity there's a significant risk of progression continued progression just simply from a biomechanical standpoint. Although I have several patients in their 50s and 60s with curves more toward the upper end of this that have not shown significant progression over a decade or two but this is the this is one concern is that if the curve is big enough it's going to continue to progress. Other concerns of course involve the risk of degeneration and back pain and disability down the road for the for the patient. Thoracic curves are the most likely to progress in the natural history studies followed by lumbar thoracolumbar double major. I'd say you know that needs to be modified a little bit because the secondary degenerative changes in the lumbar curves if there's a significant lumbar curve can cause those to to progress in sort of a secondary way after the age of 50 as the degenerative disc disease accelerates. So the reasons for treating again we talked about a little bit yesterday the clinical deformity is not to be underestimated in this patient population. Adolescence is a difficult time for many many kids and anything that that distinguishes differentiates one child from the rest depending on on that child's psychological makeup and social support can be very very difficult for that child. So the psychological effects are not not inconsiderable in many of these children and then as I mentioned the progression after skeletal maturity is another concern. So we talked yesterday about the low moderate and high risk for progression and the Cobb angle and the Risser sign so the magnitude of the curve the age of the child which is really a another proxy right for the growth potential and there's several ways to measure the growth potential of a child or estimate it right the growth history the parents height whether or not menstrual regular menstrual periods have started and the tide mark there is that after the onset of regular menstrual periods there's generally two years of additional skeletal growth that that occurs. The Risser score shown here you can see the iliac apophysis here is a Risser 3 illustrated just divided into quadrants the ossification starts laterally proceeds medially and a five would be a complete ossification of the iliac apophysis and then the hand x-rays I mentioned where we obtain just a an AP hand film and compare it to to the authoritative atlas to get a gender-specific skeletal age to help estimate continued growth. A skeletal age of 18 years being maturity. There is this genetic test of progression again this is I think still being sorted out exactly how useful this is we've backed off using it because of this cost it's not been covered by I think at this point any of the common insurance companies in our area but it's a it uses multiple markers to categorize patients as low versus high risk and there was was hope and I think still is that this could help identify patients who have what would might otherwise be considered a low risk curve if if in fact they end up being categorized as high risk based on these markers that you might intervene earlier with things like what Dan was talking about with stapling or anterior tether which are essentially internal bracing without the without the downside of the external orthosis. When we evaluate the patients who do need to do a thorough neurological examination again looking for anything that indicates that this is any anything other than idiopathic scoliosis including a skin exam look at the coronal and the sagittal balance look at the waistline asymmetry and I often start these or usually start these evaluation by asking the patients or the parents in as unleading a way as possible so what they've noticed because they'll tell you patients with a significant waistline asymmetry will say well this you know I'm always hitting my hip with my left arm but not with my right or I notice when I look in the mirror put on a bathing suit that I have a waist on one side and not on the other. Look at the leg length for small curves sometimes something as simple as a shoelift can can be effective in preventing preventing progression. Shoulder balance as we talked about a little bit is is significant and that's something that patients and parents will know and then the Adams forward bending test to look at the posterior clinical deformity element the rib hump or the thoracolumbar lumbar prominence and then finally the flexibility lay the patient down push on them sort of get a sense of how flexible the the curve is have them bend side to side and then do the full radiographic workup that we talked about. We also discussed the the lanky curve lanky classification so as we move out of the area out of the realm of non-operative treatment and into operative treatment that's where the lanky classification becomes important. As far as bracing I don't I didn't put a lot in in here about about bracing. The recent there's a recent study in the New England Journal I think last year bracing versus non bracing and it showed that bracing is effective in preventing progression and in a nice subgroup part sort of analysis or looking at the patients they they were able to determine how long the patient wore the brace each day and and basically compliance or brace use also correlated with control so we have the patients aim for about 20 hours a day if possible wearing the wearing the brace basically everything except for gym class or other sports activities. So in surgery the the goals of surgery prevent progression of the deformity during child during adulthood correction of the clinical deformity which bracing does not offer right bracing offers the possibility of a rest of progression but not correction ending up with a balanced harmonious spine with love and part of that of course is is having level shoulders. So there's several different options although more and more we're turning or using just a posterior instrumented fusion procedure doing less and less anterior surgery for AIS as we are for all spinal deformities. However interior instrumented fusion is an option interior release followed by posterior fusion is at least at our institution a historical procedure we had to actually convert this slide of an anterior release from from lantern slide because we don't haven't done one in in more than a decade and then growth modulation procedures and this is really a sub sub specialty the growing child the growing spine meaning the infantile and and the juvenile and the syndromic kids at our institution Mike Vitale basically does all of these it's with David Roy doing some of them but it's an incredibly difficult area of treatment however in the in the young adolescent or older juvenile patient anterior stapling or I think in rare cases still some people are doing these anterior tetherings where instead of a rod they're using a polypropylene rope basically to to arrest growth without doing fusion the idea that down the road, you can go in and cut that or remove it after growth is complete. The goal, as we talked about yesterday, or one goal with picking levels, is to keep the fusion as short as possible. So we talk about a selective fusion, and if you read through the literature, that's often a debate, when can you and when can you not do a selective fusion? That refers really to fusion of just one curve. And so therefore, the key is identifying a curve as either a Lenke 1 or a Lenke 5, so a main thoracic or the thoracolumbar-lumbar curve. Those are the situations where a selective fusion is or may be appropriate. There are a couple of other papers besides just simply the classification, but looking at some of the other radiographic features that may indicate that a selective fusion would be appropriate, that includes looking at things like the relative size of the two curves, right? So if the thoracic, for a thoracic selective fusion, if the thoracic curve is bigger by a factor of 1.2, then the thoracolumbar-lumbar curve, that may indicate that a selective fusion is possible. Also looking at the apical-vertebral rotation, these are all three-dimensional deformities, and there's a NASH-MO, a scaling system, a classification system of vertebral rotation based on the location of the pedicular shadow to the vertebral body shadow on the AP films. It's worth looking up a paper from the 60s, I believe, late 60s, maybe early 70s. So looking at the rotation, that's really a marker of the deformity that we miss on the AP and the lateral films, but pick up on imaging modalities like what Tyler was showing with the 3D imaging that's available now. And then finally, looking at how displaced the apical vertebra are relative to the CSVL, right? The apical vertebra being the maximally displaced, and if the thoracic apex is much more displaced than the thoracolumbar-lumbar, then that may be a selective fusion candidate. And similar criteria, looking at thoracolumbar, so these lengthy five curves, when can we fuse just the thoracolumbar curve and not the thoracic curve? Expecting that the thoracic curve is going to improve in a compensatory manner after correction of the thoracolumbar-lumbar curve as in this patient where we did an anterior fusion. Approach selection. I think it's important to know this, even though, again, we're doing mostly, even in the fives and the ones where we used to do anterior surgery, really doing all of those posteriorly. And the reason I think that's important to understand why we used to do these anteriorly is that we could save levels. So compared to hook constructs or hybrid hook-screw constructs, anteriorly could usually save about one to 1.2 levels on average compared to going posteriorly. And saving levels, of course, is important, particularly down in the lumbar spine. With pedicle screws and with derotation techniques that Joe talked about yesterday, the length of the construct for a posterior operation now is very, very similar, if not identical, to what we can do anteriorly. So we're not saving levels so much anymore going anteriorly. In an individual patient, if we feel for some reason that we can save levels, that's when we would go anteriorly. But that's really why this has moved more and more towards the posterior is that we can derotate these patients, probably do a better job with the clinical deformity, particularly that posterior rib hump, and therefore prefer the posterior to the anterior. But anterior is an option if there's a single structural curve, particularly these lanky fives are nice for the anterior, stay out of the chest for the most part. Patient should have normal or nearly normal PFTs since there is the potential for slight decline in pulmonary function. A hypokyphotic thoracic curve would be a reason to go anteriorly since this is generally a kyphogenic operation going in anteriorly. Need to have adequate bone quality, relative flexibility, and you don't want a very large child or any other significant comorbidity. And then on the right side, the relative indications to go both posteriorly, the main thing here is if there are multiple curves that need to be instrumented, posteriorly is generally the way to approach that. So again, indications and contraindications, thoracic hyperkyphosis, pulmonary compromise, certainly a reason not to go anteriorly. Posteriorly, the nice thing here is the correction, or one nice thing here besides the familiarity that we all have with the posterior approach is the ability to correct the clinical deformity. So with derotation, where we're actually spinning the vertebra in space, that leads to significant improvement in the posterior rib hump in particular. We can also, if necessary, and we rarely do this, but we can do a thoracoplasty where we resect the apex of usually three to five ribs that are maximally deformed to reduce that posterior rib hump. The situation which we still do that is patients who have a real sort of razorback, a very sharp deformity where the ribs are actually deformed. And so even though you derotate them, there's still a significant angular deformity to it, even though the prominence is less. So we'll take off the apices of those deformed ribs to give us a smoother contour and a better clinical appearance. Generally, we go cob angles plus one or two posteriorly. Beware the rule maker. It's not a hard and fast take-home rule there. I like to use more and more monoaxial screws. I rarely use fixed head screws that have no mobility. I like the ones that move in the sagittal plane. I think it stresses the screws a little bit less. I use a dorsal bony landmark technique with segmental screws. Approximately, if necessary, use hooks. I think it's important to be able to put hooks in. I don't know if we have them here on any of the instrumentation setups, but it's certainly something to look at if we do maybe take a few minutes today to look at some bailout procedures if you can't get screws in. And then beware the right thoracic curve as Bob and I were talking about a little bit yesterday, the right thoracic curve with a high left shoulder because you're gonna tend as you correct that curve to kick that shoulder even higher. And so picking the UIV, the upper instrumented vertebra, look carefully at that proximal thoracic curve, look carefully at the shoulder tilt, and also look at the sagittal plane to the degree that you can see it on the lateral film. Sometimes it's hard to see. Make sure that you're not missing an upper thoracic kyphosis that you don't wanna instrument just up to and leave unaccounted for. LIV at the other end, define the end vertebra, the neutral vertebra, and the stable vertebra. Generally, go at least to the end vertebra and then look at where your planned or proposed LIV is gonna end up relative to the CSVL. Generally like to get to at least a lanky B with your LIV, meaning you want that lowest instrumented vertebra to at least be touched at the lateral vertebral body by the CSVL. Anything that's more displaced than that generally is gonna have a significant angle at that distal junctional disc and be potentially high risk for adding on. So a couple of quick cases, a 15 year old girl, progressive clinical deformity, bracing, minimally compliant, 75 degrees, main right thoracic curve bends down to 55, a 60 degree curve bends down to 50 and change. Her upper thoracic, I don't know what happened to her, the upper bender here is 42 degrees and moderately flexible there. So this is a double major, we went to, yeah, double major, sorry. Went to about T4 here, shoulder balance not an issue, all posterior construct, and ending with a neutral stable level. Might, looking at the degree of the correction here, I think probably could have saved a level down below. As you see, we got L3 pretty neutral and pretty stable. Would be nice to save a level in the distal lumbar spine. This is sort of before some of the D rotation systems that we have now. 13 year old with a significant trunk shift. I don't have the measurements here. This is the case I showed a little bit earlier, a lanky five, flexible curve here. And one of the last anteriors that I've done, I think this was about three years ago or so, I'm not sure I've done one since then. We've gone to all posteriorly on these. But it's a nice selective fusion. You can see there's a residual curve here of no clinical consequence. And so we're not worried that that's going to progress over time. And finally, it's rare to see a curve of the magnitude of this next one. This is an 18 year old girl that had a lot of anxiety issues and had been scheduled for surgery on a couple of occasions with other surgeons and had backed out at the last minute. Ends up with an 85 degree, very stiff curve with a significant thoracolumbar lumbar curve. And this is one of the circumstances where we end up doing a vertebral column resection in an AIS case in order to try to translate this, translate the apex a little bit. And we also did thoracoplasties here. She had a razorback deformity. The other instructive element of this case that I remember pretty clearly is that, is related to monitoring. And monitoring these cases is essential. And monitoring for as long as possible is essential as well. We were closing skin. We had closed fashion. We're starting to close skin and lost our motors. Everything had been fine since then. And we sort of saw a quick loss of the motors as we were starting to close skin after a long day and open everything up. And there was a little small piece, a remnant of the dorsal vertebral body that as we had translated the apex had impinged on the cord and caused a loss of the motor. So we had to give up some of our correction, resect that. She ended up doing fine. But this was probably an hour and a half after we'd done our correction before we saw any change. So it's important to keep watching those motors. We do it until we're essentially on our very last layer before we let them stop monitoring for just that reason. So this is the archetypal spinal deformity. And even though you may not see much of it or build much of a practice in it, I think there's some reasons, compelling reasons to understand it. And if you have the opportunity to do this either with orthopedic surgeons at your institution or in your practice down the road, it certainly is a lot of fun, very rewarding and a nice break in a way from the rigors of adult deformity surgery. Thanks.

adolescent idiopathic scoliosis

curvature of the spine

treatment options

psychological effects

surgical approaches

fusion levels