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You all the way from Yarmouth. So um please bear with me if things don't go so well. Um So the first thing is what the first thing I wanted to cover was what is adult deformity? What is adult degenerate adult scoliosis? Um Because you might think it's an age definition based on, you know, once you get over 18, you're an adult and therefore you have adult scoliosis, but there are two distinct pathology groups with adult scoliosis. Ok. Um So the first is the adolescent idiopathic, which you've been hearing about all day that turn 18 and become adults. So they're adult idiopathic scoliosis. And that's the same pathology just in a slightly different age group. And my co to you, I'm not going to spend a lot of time on that because my counsel to you is treat that pretty much the same as the idiopathic curves. They've completed their skeletal growth. So their risk of progression is a lot less. But in terms of angles measurements, pathology and principles, they are all very similar except for you might notice that the curve is going to be a lot more stiff. The dissection is more difficult Um So you uh probably need to plan your metalwork density a bit differently. But um those young adult scoliosis, that is a progression of the idiopathic scoliosis that we see that is a distinct pathology from what I'm going to spend most of my time talking about today, which is the adult degenerate deformity. So the scoliosis Research society consider that to be the people over 55. But in reality, the exact age cut off isn't really important. It's the identification of the different pathology and therefore very different challenges that you get. So, in the idiopathic group, they do have a difference in um sagittal profile, but it tends to remain fairly well balanced throughout their life. Um But in adult deformity, as you'll show with a an exam, good examples. Um Sagittal profile is key. So it's not so much about the coronal plane deformity. So the SJ PC on, on the A P curve, it's more about the lateral x-ray and the tilting forward, the pelvic tilt and all of these exciting things that I'm sure you're all desperate to hear about. Um One final point is, don't forget in adult deformity, the iatrogenic deformity, I the ones that we have caused or the ones that we have made worse by performing surgery really start to come into their own in this age group as well. So those with some um some sagittal plane deformity that we where we fuse one level and we fuse that incorrectly and we create a whole bunch of other problems that cascade up the spine. Um, those that have a slight curve are taking bone away and that curve becomes much more progressive and progresses rapidly because we've destabilized the curve itself. Um, those ones are also prevalent as an what I would call an adult deformity. Ok. Um, and something that you're much more likely to see in an adult just because more adults have surgery. Ok. So just at the back of your mind, don't forget that there is an iatrogenic group here. Ok. And that, um, that's kind of one of the whole principles of the get it right. First time thing in spine surgery is that if you, um treat one level badly, then you can cause a deformity that starts to create a whole cascade of events. Um, so in, in the back of your mind, just have the iatrogenic group. And if I was doing an exam viva, um, it would be one of the things that I would mention sort of low down the list. But I think something that's important to consider and always have on your, on your little radar, um, look for signs of previous surgery. Um, and whether that might be something to consider. All right. Um, so as I said, adult surgery is less about the coronal plane deformity as you can see from this x-ray, they do get a Coronal plane deformity. But, and that is important and it can often be um a, a consequence of rotation just like in uh idiopathic scoliosis. But um the way the spine responds to that coronal plane deformity is very different and the coronal plane deformity is less of a problem. Ok. The curves are very stiff. Ok. So, one of the main principles of adult deformity is that you can't, you know, you can, but you are much less likely to be able to force this spine where you want it to go just by putting some screws in and putting some big metal rods in like you can in idiopathic scoliosis. Ok. The forces we use in idiopathic scoliosis are already high enough and these curves are very stiff, they're not gonna move if you just give them a pull. All right. And you're also talking about a patient group in which they bone density is starting to reduce. So they've, they're well past their point of peak bone density and therefore the grip that you're gonna get with your pedicle screws is gonna be less and therefore you're gonna be able to ask less from your screws. So you can't rely solely on putting some big screws in and putting some big metal rods in. You've got to do something to address that stiffness, ok? And we'll talk about that a bit later as well. One thing I really wanted to talk about as a bad prognostic sign and something that you'll see in the textbooks is lateral slip. OK. So the lateral ESIs that you see here. So if we look at, I don't know if you can see my point of it. If you can. We've got L5 down the bottom here, which is looking quite stable and level. We've got L4, which is quite a quite drastic tilt. But when we come over to L3, what we see is due to some of the rotation and the lateral ESIs that that bone is significantly laterally malaligned when compared to the bone below. And that's a very poor prognostic sign. Ok. What it means is that the acute rotation of the spine is quite severely mismatched between one level or another and that this bone is rotating off the, the bone below it. And of course, what that does is it allows the deformity to progress quite rapidly because there's a mismatch between the forces that are applied through the bone. And so that is a poor prognostic sign and something that if you see it, you should have a sort of a discussion about, you know, if you're talking about principles and things a discussion about that in itself AAA an indicate a relative indication for considering surgical intervention. Um But if you see that the worst thing you could do is an isolated decompression because you're almost certainly going to upset that and cause worsening of the deformity, which is where your eye Atro deformity starts to come in as well. OK. Um Rotation does remain a significant contributor in these um patients, but the deformity is about so much more than rotation. Um And the coronal deformity that you see in the idiopathic curve is much more complex. OK. So as I said, the cob ale tells you only part of the story. OK. And the cob angle you might be fed up with by now. And indeed, it's a problem you've got a whole world of other wonderful angles that you can remember in a deformity. And um I'm going to try my best. They can be quite confusing when you first introduced to them. And so my um my advice to you is that don't worry if you don't get everything I say today, number one, obviously, it's recorded and you can look back on it. OK? But number two, just go away and have a little read about them, have a little um think about what these angles are actually measuring and what they actually represent and how things are moving to change those angles and why they're moving. I would try to explain that today. But if you can understand that, then you can understand quite a lot about the compensatory mechanisms and a lot about the decision making surrounding adult deformity. You, you'll have noticed me already s a couple of times, talk about balance. OK. So there's basically balance is a way of describing what happens to the spine when you ignore the bit in the middle. OK. So is the head over the top of the pelvis is essentially the question. OK. And you there are various angles you can measure et cetera. But what you're really asking is is the curve balance. So whatever happens in the middle, does everything cancel itself out to create balance? Or at least if it doesn't is the body able to employ its compensatory mechanisms to try to maintain that balance. OK. And the final thing about Scolio is about degeneration that I want to impart as an important key concept is failure is everywhere. OK. So screws fail, fusion fails. Um if and the spine can fail. OK. Um So a lot of the principles that we employ are about trying to prevent failure. OK? So it's as much about trying to prevent what you've done from failing as it is about doing the actual correction. OK. So, um and, and unless you get all of that right, first time, what you will have is failure. OK. Sick. What we've got here is a very basic representation of a lateral radiograph of the pelvis. OK. And what you will notice is that down the bottom here, we've got a circle which is the femoral head. OK. So the first thing is your x-ray must include the femoral heads. And in theory for, if you've got a good radiograph, those should be overlapping or near enough perfectly overlapping. So that you know where the center of the femoral head is OK. Also on your lateral radiograph, what you need to see is the sacrum and you need to be able to clearly define the, oh, sorry, you need to be able to clearly define the superior endplate of S one. OK? And if you can't see those things, then that x-ray is not going to tell you what you need to see. All right, and you'll see that that's not I I it's very difficult to take a good one. A good x-ray, especially in scoliosis. All right. So we've got these three angles that we're gonna start with. And these are the first concepts that we're going to introduce. So the first is sacral slope. How much is the superior endplate of S one sloped in a downwards dire direction compared to the horizontal? And it's as simple as that. So sacral slope is just, how much is that downward slope compared to the horizontal? Ok. And I'll give you a table of normal values in a minute. So don't worry about what the normal values are quite yet. Alright. I I just want you to understand the concept. The second value that I want to introduce is pelvic tilt, ok? Your pelvis can retroverted and Antivert, ok? And what you can do and you can actively do this, you can probably do it sitting on the chair right now if you want is you can tilt your pelvis backwards and forwards and what that does is it affects the alignment of your spine. Ok. And so it's one of the compensatory mechanisms that the body can introduce, tilting your pelvis forward will increase your pelvic tilt. Well, sorry, we'll decrease your pelvic tilt because what you'll do is you'll bring your sacrum up towards the center rotation of the femoral head. And so as your sacrum comes up, your sacral slope will increase because your tilt cause you're twisting your pelvis up and forward. But your pelvic tilt will decrease as you retroverted your pelvis, the sacrum and coccyx will come in a downward direction which decreases your sacral slope because the S one becomes more horizontal but increases your pelvic tilt. OK. And so that introduces us to this final concept called pelvic incidence. OK. The pelvic incidence is actually by definition, the combination of pelvic tilt and sacral sle. OK. It's a constant measurement that define is individually specific, but it defines the um relationship between sacral slope and pelvic tilt. OK. And is pelvic incidence is sacral slope plus pelvic tilt? OK. And what you can do is you can actually draw a line at 90 degrees to the superior border of the N plates of the sacrum. And you can draw another line from that center of the SS one Nplate down to the femoral head. And the incidence is the angle subtended by those two lines. OK. But what they actually represent is sacra slope plus pelvic tilt, which is a constant of your pelvis. Ok. I'm sure that's all clear as mud. Ok. But why is that important? Ok. Well, it's important because it tells us about the compensation, but it also tells us about the normal anatomical makeup of this person's pelvis. Ok. So that pelvic incidence is a constant. OK? And that pelvic incidence should have a relationship to the lumbar lordosis. OK. So the lumbar lordosis is essentially a cob ale that you take from the side. OK. So you take it from the superior end plate of LL one and the superior end plate of S one. OK? And you take an angle. So tender between those two and that's your overall lordosis that your lumbar spine achieves that lordosis should be within 10 degrees of your pelvic incidence individual. OK. So when, and it's when you start to get mismatches between these, that we start to lose balance. OK? And these are the normal angles, OK. So pelvic tilt should be 13 degrees plus or minus six crus leg, 42 degrees plus or minus eight pelvic incidence, 55 plus or minus 10. And you'll see plus or minus 10. It's quite a lot actually, Lumb lordosis is slightly different to men and female men have slightly less. OK? But again, plus or minus 11 degrees allows quite a lot of wiggle room. Thoracic kyphosis is 40 degrees. And you'll see that that's roughly similar to the lumbar lordosis ie they cancel each other out to achieve balance. OK. And don't worry about the sagittal offset value. Ok. So pelvic tilt should be 13 sacral slope, 42 pelvic incidence, 55 et cetera, et cetera. OK. So these are the numbers if you want to learn them for the exam as the normals. OK. And they are important. OK. But the ranges are quite broad. So it's all really about the relationship between them and the mismatches specifically. Oh, so what I want to talk to you about now is more of a diagrammatic representation of what I was trying to explain before. How do we achieve balance and how does the pelvis change and this concept of retroversion? OK. So these, these A and D these are balanced curves. OK? And what do you mean by balance? Well, if we draw a line straight up from the center of the sacrum? OK. And a line from C seven plum line down which is just a line straight down from the center of C seven on the lateral view is that within an acceptable distance? OK. And if it is then the curve is balanced, OK. We start to over here get into the complicated realm of compensation. OK. So the body can achieve balance by retroverted the pelvis. So you if you see here, this sacrum is um more anteverted. I it's coming closer to the center of the femoral heads, we can retroverted that pelvis by tilting it backwards. And what that does is it can compensate for a loss of lumbar lordosis. OK. And keep that C seven plum line within the realms of acceptability over the top of the sacrum. OK. So what the body is doing is it's bringing the pelvis back, which is pulling the whole spine in a more upright position. OK, which is bringing C seven back. And as it's bringing C seven back, it brings that sa uh C seven plum line closer to the center of the sacrum. OK. So that's one big compensatory mechanism. OK. That allows the spine to achieve its um balance. OK. And what it can also do is it can employ this mobile transitional segment in the middle of the spine to recreate a bit of lordosis. So this would be normally a transitional, fairly flat segment between T 10 and T 12. And what it can do is because it's mobile because it's the floating ribs is it can employ a little bit of lordosis here to compensate for the lack of lordosis in the lumbar spine. OK. If we look down here again, this hidden imbalance, OK. So I compensated loss of balance. What we, what we can also see is that that employment over a period of time of lordosis over that transitional segment can be can become higher. OK? And that pelvic retroversion can continue to develop such that um we compensating more and more to try to bring that pelvis over the back. OK. And then on this final sort um section over here, what we have is the pelvis not being able to compensate any further despite maximum retroversion, despite employing all our compensatory mechanisms and the sac, central sacral vertical line or the sagittal vertical axis, which is what SAS VA stands for starts to become quite significantly positive. The patient starts to develop what we call a sagittal plane deformity. I their whole body is tilting forward and that is the first step of failure. OK? Because when the body starts to tip forward, the forces at the center of gravity continues to move forward, there's more force on the anterior portion of the spine, the muscles start to fatigue everything out faster and they actually a downward spiral. OK. If you have a low pelvic incidence, it's much more difficult for you to compensate than if you have a high pelvic incidence. Ok. Sorry, other way around. So if you have a low pelvic incidence, the compensatory mechanisms are a little bit easier. OK. But, and, and so low pelvic incidence, you employ a bit more of your compensatory mechanisms for the same result. Does that make sense? Ok. Dear, as mud, I'm sure you'll have to go back through it and get it really right in your head. OK. So this is a case. OK. And this is a case that um we've done fairly recently in Norwich. OK. So this is a pre op film as you can see, the um x-ray is as clear as mud. Ok? But there's the center of her femoral head helped by the fact that she's had a hip replacement. So for us to see there's a sacral slope. Ok. So that's her sacrum there. And what you can see is her sacrum is almost horizontal. I'm sorry, almost vertical, which means she's retroverted her pelvis. So she's maximally compensating. You can see here, her lumbar spine is almost dead straight, isn't it? You could, she's got barely any lordosis here. She's compensated by removing as much of her thoracic kyphosis as possible. But yet she still has a huge positive sexual balance, ok? 15 whole centimeters, which is vastly higher than it should be. Her sacral slope is low. It's only 12 degrees cos she's retroverted her pelvis. Her pelvic tilt is 28 degrees cos she's retroverted her pelvis all the way back. Ok. And her lumbar lord pelvic incidence is 40 degrees, which is that constant and her lumbar lord A is only two whole degrees. So rubbish. So the sacral slope is low, the pelvic sorry, the sacral slope is low. The pelvic, she's tilting her pelvis, the pelvis is compensating, the lumbar lordosis is hugely low and it's just way too much loss of lordosis for her spine to cope anymore. She's unbalanced despite employing all of her compensatory mechanisms and therefore the FV is very positive. So what's the solution. Well, she needs a whole ton more low doses, doesn't she? So, what we need to do if I go back to here in a minute is we need to bring this all the way back over here? Ok. So the only way you can do that, so you can either straighten her kyphosis, but she's already doing that and it's not working or you can give her low doses to curve her lumbar spine back such that we can put her spine back, her head back over the top of her pelvis. And if we don't achieve that, everything we do is fighting against gravity all the time. OK? So unless we get her C seven plum line somewhere in the, in the vicinity of her pelvis, then everything we do is gonna be fighting against gravity for the whole rest of the fixation and either the screws will pull out or she's gonna fall off the top. So the bit that we don't fuse is gonna continue to move forward. So this is what we did for this lady. OK? And it's a really good employment of the um of the principals. OK? So the first thing we did is a whole bunch of releases. So we did an operation at the back of our spine. We took out all of the facet joints and we put some screws in just because we were there. All right. But the screws aren't part of the release. We took a whole bunch of bone away to give as much movement as possible because you know, this is gonna be stiff. OK? We also know that the L5 S one is the most likely place to not fuse. OK. Cos that's the bit where the most force is going. And it's also the one where you've got sheer forces which as I'm sure you will know from your basic science, shear forces are bad for bone union. All right. So then what we did is we did anterior lumbar fusion. So we went to the front of her spine which allows us to do even more releases, releasing an anterior longitudinal ligament, take out the entirety of her disc. And then we put some lordotic cages in her spine. So, so basically some wedge shaped cages to wedge that spine open and to try to recreate that lordosis. So, whereas before she had almost no lordosis, only two degrees, we give her 38 degrees of lordosis. OK. Her pelvic incidence has changed to 59 degrees. She's got a pelvic tilt to 30 degrees and her sacra scope is 29 degrees. OK. So that pelvis com, her compensatory mechanisms are no longer to the extreme. And as a result of even just doing that first stage of releases, we've only addressed this tiny, little bit of a lumbar spine. Ok. We've not even touched anything up her high spine yet she's on already gone from 15 centimeters positive to four centimeters, which is much more acceptable. Ok. So it's really powerful to do a, a good base correction. So, correct the base of the curve, employ lower doses good releases. And from that, you can really affect the overall alignment of the spine. Ok. And then we did stage two, which is concentrating a bit more on the Coronal correction, but also fine polishing the, the, um, the Sagittal correction and unfortunately she hasn't had a full length scoliosis views, but we already know her saal balance was acceptable. You can see that we've put some long rods down into her pelvis. Ok. So she's got S one screws and then she's got S two IACC screws. She's got screws all the way up. She's got an excellent, lovely Lordosis here. We put another cage in from the back to the level above just to get a good fusion to reduce her risk of nonunion. And overall, she's now standing upright. We've corrected some of her Coronal plane deformity as well. She's still got a bit of electral ESIs here, which I did tell you to be wary about and we are wary about it. Ok. But overall, her balance is much improved when compared with before. How do you decide how far to go? Well, you need to get way past the bit where you, where you're employing your curve, but you also don't want to stop at the apex of any kyphosis because if you stop at the apex of a kyphosis, they're gonna continue to slip forward and fall off the top. Ok. So, Nonunion is our main point of failure. It's usually at the bottom of the spine and it is a big old race. Ok. So it's now a race between her fusing and her, um, screws rods, something breaking. Ok. She can also fall off the top of that construct. Ok? And that's why you got to choose where to stop and choose that point. Usually a couple of levels higher than you think it's gonna be at any fixation point. The screws can pull out and we always get Dexa scans, but they can be falsely raised because of the overlap of the bone and because of the sclerosis associated with the um lumbar spine, scoliosis. So, hip e hip Dexas are more reliable, lumbar spine, Dexas can be falsely raised and we need to be aware and we know the complication rates are high and I'm going to quickly talk to you through a little bit about anterior surgery, something that you won't have heard of. So far posterior surgery, the approach is easy, just make a cut in the middle and peel the muscles off. Ok. For anterior surgery, you need a bit more an anatomical ana uh awareness, ok? And it's an anatomy that we're not used to in our um spine training. Ok. So it's a, you can either use a laparotomy style incision or a fan of steel. But um, it, it doesn't really matter. You make your incision in the midline, you find rectus abdominis and you one centimeter from the lateral border, incise the rectus sheath, you then dissect the muscle so that the muscle goes medially. Ok? And you gently then go through the, in the, um, the second layer of the rectal sheath. OK? Which takes you into the abdominal cavity if you're in the midline, OK. Once you're in the abdominal cavity, you stay extraperitoneal. So outside the peritoneum and this is a retroperitoneal approach. So you should not be seeing the bowels. You should just be seeing the peritoneum except for the colon, the descending parts, which is a retroperitoneal structure. OK? You then stay nice and natural, work your way right around the pelvic wall until you feel the iliac crest. Once you feel the iliac crest, you can then get onto Ile Ais and you can gently sweep all of that bowel away. So you turn your hand around at this stage, you sweep all of that bowel away, OK? And start to work your way backwards and across towards I OS, OK? When you get to I OS, you'll see the ureter and of course, you don't want disrupt that, OK? And that goes with the peritoneum, OK? Once you retract ureter, you then come to the medial border of service where you start to get into Tiger territory, OK? And at L5 S one it's below the bifurcation of the IV CS and the um ileac. So you, you can either then work in between them. So come over the top of them and work in between the trouser legs, which is obviously fun because you've got danger everywhere you go or you can gently dissect them off and peel them away from the anterior portion of the disc, which allows you a good access to the disc, ok? You must take out the entire disc, OK? Um And you can release the A L, OK? And there are a whole bunch of complications to worry about which we're gonna go through in the next stage. But that's your approach. OK. So it's a retroperitoneal approach. You incise the rectal sheath, dissect the rec go lateral to the rectus abdominals, muscle inside the internal portion of the rectal sheath, stay extra peritoneal. Take, make sure you go lateral to the colon, take that with you. OK? It's always left sided because the liver's out of your way. All right. Um Come over the top of, so take your beware or two, you can find it because of the peristalsis. OK? Take that with, you, find the veins and the vessels and uh either work between them or dissect them off. OK? Always do this with a vascular surgeon. Uh almost everywhere I work except for Ipswich has a vascular surgeon. Now, um access. So, always have a vascular surgeon with you because if it bleeds. It's very bad. This diagram on the right is just really a brief pictorial representation just to help you with the um the nomenclature. So a Alif anterior lumbar antibody fusion, it's showing straight through the middle, but actually, obviously it's a priority, no approach, but you're approaching the disc straight on. OK. So anterior straight on um oh is oblique. OK. So what you do is you come in this oblique channel between the muscles and the vessels, OK? And you're putting your disc in, you're putting your cage in from a side on you. But rather than um putting it in um in from that oblique channel and turning it anteriorly, what you're doing is you put it from the oblique channel and you're coming in more laterally. OK? This over here is lift, OK? Or extreme later. That's a Trans P OS approach. So what you do obviously at this level, you would, you wouldn't do it at this level because the I crustal is in the way, OK? But what you do is you make your incision, direct lateral, OK? You come move, you move your peritoneal structures away and then you, oh sorry, then you employ this plane here. OK? Which might be behind the kidney or whatever. All right, then you find P OS and you use directional um uh directional um neurophysiology monitoring to work out where your lumbar plexus is. Once you know where your lumbar plexus is, you employ your tractors to obviously to stay away from the lumbar plexus and then you split O us and you can get to the disc that way and come all sideways, which means you stay away from the vessels, ok? You obviously need to make sure you're far enough forward when you're doing this approach so that you don't approach into the canal, which is very easy. All right. T liff is transforaminal, which is a posterior approach that comes this way and then cliff is posterior which comes direct from the back. Complications avail live obviously, bowel damage, vascular damage, which includes death. You're much more likely to get a venous thromboembolism. And so you wanna be able to restart anticoagulation quickly on these because you're retracting the veins and therefore you're gonna get venous stasis damage to the ureter damage to the bladder. So you catheterize them, that's very important. And there's this little thing called the hypogastric nerve which supplies the sexual function in men. And therefore, you can get sexual dysfunction, retrograde ejaculation. And that is the thing, believe it or not, that puts almost all of the patients off from having. It's not the bowel damage, it's not the bleeding to death, it's not the damage, it's the sexual dysfunction. And that's the thing you get to that. And that seems to be the, the nail in the coffin for a lot of people who decide not to go with the anterior surgery. Ok. So just as a pictorial representation. So just because it, it wasn't so clear on the last one. This is your xli or lateral lumbar to body fusion. The complications to that are pretty much the same as an Alif plus lumbar plexus damage. OK. So the lumbar plexus sits inside. So us and so you're going straight through that. And so there's a risk of damage to that, OK? You can damage the kidney if it's up high. OK? As in if your approach is up high and you cannot get to L5 S one, as I said to you before, because the iliac crust is in the way. So you have to do that anterior oblique. Um that is a whistle. So tour of the angles associated with um into body fusion. All right, I'll stop sharing so that everyone can see what's going on. Um The key principles are work out what's wrong and why it's wrong. Work out how the patient is compensating and whether they're still balanced and whether they've overcome those compensatory mechanisms. OK? Don't worry as much about Coronal balance while it's still important. That's not the main thing. Sagittal balance is your key failure method. OK. And recreating low doses has to be key, the spine is extremely stiff in these people. OK? And so releases are vitally important. OK? You can't force the spine back to where you want it to be. You have to release it. OK? And you buy those releases then you can bring things back. You don't have to go anterior, but it increases your fusion ability. OK? It also increases your release and therefore can increase your correction. OK. The reason it increases a fusion is because you can put a much bigger cage from the front than you can from the back, bigger surface area, better fusion. OK. Um But it's a multitude of methods. It's huge surgery in patients that are less fit because obviously they're older. Bone density is also key complications are high. And so this is not a decision to be taken lightly, any questions. Oh OK. So hang on, I've got some questions here. Uh So do you attempt fusion on, on, on smokers? Absolutely not. OK. This is such a big operation. You don't want any chances fu uh the use of nicotine. So it's not just smoking, the use of nicotine increases your nonunion rates by up to 20 times. So you do not get on the operating table for any fusion. For me to be honest, if you have not stopped smoking and if you are not invested in your health enough to stop smoking while you have your surgery, then what, I'm not going to invest the time in you to have the operation. And I know that can be controversial, but there is very good evidence to say that that is um a very detrimental thing. And so I don't offer fusion to patients who still smoke Ok. Um, if the dexo shows osteoporosis, do you not go ahead with surgery? No, the best thing you can do in that circumstance is optimize their bone mineral density, which includes a referral to the rheumatologist, starting various infusions, even teriparatide if you need to, but you wanna have optimized that before you do any surgery. Ok. Because again, you don't want your screws cutting out. The worst thing you can do is an operation that fails. OK. Tlif is an alternative to Alif. Yes, it definitely is. OK. You definitely don't get better as good fusion rates, especially at L5 S one. And you, and I'm certain you don't get as good low dose as correction. Ok. So it is an alternative and there are units doing all posterior corrections because they don't have anterior surgery and indeed, they didn't have anterior surgery in no, relatively recently. But um, in my hands, a LIF is far superior for those reasons. Ok. Hip first or spine first. Ok. All right. So, hi. So, um, really what you're talking about there a is, um, is those with degenerate hips who therefore can't use those compensatory mechanisms more sort of most commonly, you'll see that in something like an bond? Ok. Um That compensation is slightly different because uh because they have a few spine and so they can't employ the compensatory mechanisms as well as, as well as they might. Um But if you've got arthritis of the hip or the spine. Um, for me, hip first every time. Ok. The two reasons. Number one, it's a much easier and much more reliable operation. Ok. So they are much more reliably gonna get pain relief from their hip. And if that makes their life, their quality of life good enough, then they may never need their spine surgery. So, hip first for me, every time, do you use the lengthy classification for determining upper level of fusion in D Gensco? I don't, so I'll be honest with you, I don't often use any classifications. I find them helpful only for understanding principles. So my counsel to you with regards classifications is to learn the principles behind the classification rather than memorizing the numbers. OK. So if you can understand why that class is as it is. So why does this matter? Why does this matter, how do I put all those things together? Why does the combination of this and this make it worse than the combination of this and this? Then if you can understand those principles that will serve you much better than memorizing numbers on a classification? OK. So I don't use any classifications personally. OK. Um But yes, that, that is a method OK. Is approached to Axon different than normal deformity correction. Yes, because you can't free it. Yeah. So basically Axon is fused all the way. OK. Um And so you have to un fuse it. OK. So that's not the same as doing a release. Ok. Um In Axon, you're talking about doing osteotomies and you have to do a bony level correction. You can't correct through the disc. You have to correct through the bone because it's all bone pretty much. Ok. So that's a very different method and uh something uh that is a whole another torque. Ok. Uh Can I fill out a form? Thanks. Uh What patient factors influence who, who gets offered surgery? Ok. So sagittal imbalance is actually not as high as you think. Ok. But patient factors, so how much pain they're in, how motivated they are for the surgery? The BM I, their smoking status or the BMI I is falsely low. It's falsely high in these patients. So they lose height, um, their compliance, their overall general health, their bone mineral density, the deformity that they have and whether it is solvable and a multitude of other things, including not least sort of personality and whether they're the kind of person that's gonna cope with the rehabilitation and the very long recovery up to two years to recover from this surgery. So they have to be invested in it. Ok. And the people that can't comprehend or understand that properly are probably not ready for surgery. Does that make sense? And anyone who's in any doubt whether they want the operation, um, they shouldn't have it. Ok, because they, they gotta have it, they gotta be ready for it and they got to know what they're getting themselves into. Ok. So if, then in any doubt, whether they want it, then I'd say they probably shouldn't have it. Ok. That's all the questions. I'm a little bit late five minutes, but never mind. Awesome. Thank you very much, Mister Marm. Um Fine. So I think that's the last talk for today. So if, uh, and we'll just make sure you fill in your feedback forms and, uh, I think that's about it. Cheers. Thanks very much. Thank you.