 Once you start trying to interpret your anatomy as a clinical neuroanatomy, it becomes a correlative clinical neuroanatomy, translational clinical neuroanatomy, things completely change their perspective. You understand? So, let's talk about anti-survival fixation, the indications, technical tips and complications. So, basically we say that, oh everybody is getting old, but sometimes you know these patients have cervical myelopathy and we think they are getting old, you know. So, we know that, what are the indications for anti-survival disease? All of you I think know the difference between Smith Robinson and a Klobber's technique. So, basically they are just names of two scientists, Smith Robinson is just putting on a veg graft, right? And Klobber means there were, Klobber was another famous scientist, a neurosurgeon, so what he did was, he had a cylinder, so what you do is, you first put the cylinder, take a dowel of tissue, dowel of tissue from the eye lacrest and you put it at the cervical spine and just kind of drill it through, manually drill it through. So, exactly the same size dowel is taken out from the cervical spine, so then this dowel you put it there, so that's the Klobber's technique. Smith Robinson on the other hand means you drill and then take a wedge of bone and fix it there, so that's the difference between Klobber and Smith Robinson, both of them are equally useful and so therefore, what are the indications? Of course, you all know this, these indications, one is osteophytosis, disc and single or multiple level radiculopathy and if there you are talking about radiculopathy, then there has to be when would you operate, if there is a persistent neurological deficit, progressive neurological deficit, if there is a static neurological deficit, but with severe radiculopane that is your indication and of course, there has to be a clinical radiological correlation. So, these are your indications for surgery for this. Another very interesting thing is that if you review the literature on this, I mean I am just going to the next level because I am sure you all of you know about cervical. So, the important thing is that they found out that rather than you know doing a copectomy, a long segment copectomy, spinal stability was better maintained and there was less chances of kyphotic deformity developing by doing a multi-segmental disectomy rather than doing a long segment copectomy. So, unless there is something which is pressing from behind the body, if there are osteophytes or multiple discs of multiple level, then a lot of people recommend multiple level disectomy with osteophyte removal rather than doing a long segment copectomy. So, when would you not do a vertebrae to me? So, if you are doing a copectomy, anything more than three segments. So, anything less than three segments, you could do a copectomy, but anything more than three segments, then I think it is much better to go from the posterior approach, you do a laminoplasty if there is kyphosis or a laminate, I mean depending on what it is. But definitely, definitely with a long segment compression, canal stenosis, no copectomy, less than three segments, that is the recommended thing right now. And of course, we all know the other indication, we have an ossified posterior longitudinal ligament, different discs, tumors, fracture subluxations, you know this. So, you have a fracture subluxation, all of them will require plating, so now we come back to this. This is my favorite quote, so this is a very interesting thing, so now what we need to do is to actually go back and plan the surgery, before we actually do the surgery. So, coming on to this, correlative anatomy, what the very interesting thing is if you look at the vertebral artery, so vertebral artery goes through the foremen transversarium here. But if you actually look at the vertebral body and look at the groove of the vertebral artery, there is a very interesting thing that you will observe, where will you actually injure the vertebral artery in a copectomy or in a dysectomy, at what point will you injure, when you start your surgery, when you end your surgery or in the middle of your surgery. The vertebral artery is right in the middle, between the anterior and the posterior bodies, you just see the groove, so there are two points at which you can injure it. One is when you are using your monopolar to actually dissect of the longest coli here. And when you dissect of the longest coli here and your monopolar goes here inside, that's when you injure it. And the second point where you injure is when you are drilling it and you are standing on one side and the drill goes oblique, reaches the cortex at the middle of the vertebral body and goes laterally, that's where your vertebral body is. So, although you will see the vertebral artery when you are actually doing orthophyte removal right at the depth, the greatest chance of its injury are at the middle level, when it is directly lateral to it. Just remember that, so when you are actually doing a copectomy, you must be continuously aware of the midline. So that's one important thing, so you have to define that, that's the second thing that you need to do. Then the other thing is, where is the oncovertible joint? That's another very important thing, where is the oncovertible joint? So, Zygapophysiologian is simple facet joints, okay. Oncovertible joints are these, you know the edges of the vertebral body and why are they important? Why are they important? So one is that, the second thing is osteophytosis always occurs at this point. Why does osteophytosis actually occur? So in an unstable spine, it's trying to become more stable. The only problem is, either it impinges into the intervertible formula, or it impinges backwards and causes core compression, right? So is that clear? So this is all correlated in your anatomy, right? And the other very important thing is, I mean, when you're actually doing surgery, when you're actually doing surgery, please look at the range of movements. You know, because sometimes what will happen is, there will be bony and chelosis at multiple levels. And along the bony and chelosis of multiple, the point where there is a disc collapse will be the only point which is moving. The postoperatively, the patient says, what is the commonest complaint the patient will make when you fuse such a spine? There's only one movement. There's a bony and chelosis C345, bony and chelosis 12. So you have to prognosticate, you have to tell the person. So you must remember the range of movement. And another is short neck. This is a big mess, because if there's a short neck, there's a big mess, because then you need to give extension and a lot. So these are small practical points which you need to look at. Now, supposing there is, what are the major continuum? When it's a severe osteoporosis, definitely you need to be careful. The second is some trauma, tracheosophial trauma, there is a mild fistula or something, infection. That's what I'm saying. But then you need to also look at the red herrings. What do you mean by red herrings? So these are false. These are false things. You think of something and it's actually not that. You understand? So you think of cervical spondylosis, it's not really cervical spondylosis. So what are those things? If you get fasciculations, if you get disproportionate wasting, then if you're getting weakness much more than tightness, that's a red herring. Then very important thing, hundreds of patients have seen patients make a mistake. Short shuffling steps with less arm clearance and asymmetry. So always look at their arm clearance. A patient with cervical spondylosis will not have any difficulty in arm clearance unless there is weakness of the arms. Decrease arm clearance with short shuffling steps. So gait is not only lower limbs, it's also upper limbs. Very, very important. That's one thing. The second thing is joint pains, red herring. You must make sure there's red. Then step ladder deficits, that's a sign. You will get some osteophyte somewhere, but it might be indicative of, in surgical terms, even an AVM. Some bleed within this. Then some cerebellar or central chord signs, you know that. And sudden weakness with minor trauma, look for what? Sudden weakness with minor trauma, what do you look for? C-rejunction, Atlanta Exile Dislocation. And of course, if there is pain, pain will never happen. That's a red herring. You've not gone with contrast study done. So if you get a contrast study done, you will get enhancement there. That's a tuberculosis or rheumatoid or whatever. So these are red herrings. You must always remember all these when you're diagnosing. Of course, we all know about the usual stuff, so I won't talk about it, but let's talk about the Pavelov's ratio. What is the Pavelov's ratio? Pavelov's ratio, canal body ratio. Not body canal, canal body ratio. So canal body ratio, it's usually one, right? So 0.7 to 0.8, I mean, that's the thing. The other thing is, what you really need to look at whenever there is an osteophytosis is either a static or a dynamic diameter. And what is a static diameter? What's a dynamic diameter? So static diameter is from here to here, from here to here, body to spinal, the minor line or the basic spinous line. This will never change. Never, never change. What will change is the dynamic diameter. What is the dynamic diameter? From here to here. The posterior part, the inferior most part and the posterior part of the border here to the uppermost part of the spinal laminar line of the vertebra below. And this inflection extension will definitely change. So always look at dynamic diameter when you're looking at osteophytosis, right? The other very, very common mistake which everybody makes. So this is the base diameter and this is the facet. So this part in between is the laminar. So the canal extends from here to here. Don't say the canal is narrow by looking at this point and operate wrongly. The canal extends from here to here, right? This other important thing is ishi hara index, which is the curvature, curvature. I mean, you just look it up. I won't go into detail, but you must know that there is actually an objective way of assessing spinal curvature. Look it up and I'll, you know. So of course, what you need to do is that when you're looking at an MRI, what are the common mistakes that you make? Common mistakes that you make. Diagnosing cervicals, ponderolotic, myelopathy, when there is a sagittal plane deformity. What do you mean by a sagittal plane deformity? So somebody has a tauticalis, okay? Now what you're seeing is that when you are taking a sagittal section, at some points you have a mid-plane section and at some points you have a paracetal section in the same section. But you think, oh, there is ponderolotic myelopathy without assessing the coronal images which are not there and without actually looking at the patient who has a scoliosis which is less than 30 degrees. So you can't actually see them without their, I mean, unless you remove the clothes, right? Just make sure there is no scoliosis, right? One important point. The second thing is taking two thick sections. That's the second mistake. The radiologist doesn't want to give you too many sections, okay? So you will miss out an osteophyte or a disc. Take thin sections of the area if required. Ask him to make thin sections at that particular level. When you're doing a clinical examination, you must always write your point of suspicion, your clinical level of suspicion. There is the importance of the clinical examination. You say, this is C5 myelopathy. Please look at C56 or look at 4, 5, whatever, right? You must specify this, that then they look at it carefully, right? That's a very important thing. So now, when would you actually go in for a 360 degree fusion? See, sometimes, you know, there is severe osteoporosis. There is significant kyphotic deformity. Significant kyphotic deformity, one-side fusion will not work, right? And then, of course, there are several risk factors for non-union. Somebody is on glucocorticoids. For example, if somebody is on glucocorticoid for rheumatoid arthritis. Severe rheumatoid arthritis. Glucocorticoids for a long time. You need to actually do a complex, long-segment fusion. Otherwise, short-segment fusions don't work for these patients, right? So you must be aware of the fact that, you know, these are segments which will require long-segment. And the other thing is, when would you require a fibular graft rather than an iliac graft? When it's more than three-level long-segment. So there, you know, iliac graft, it will curve, so you will not be able to mold it into place. So, and then, of course, we talk about the incisions. So we all know these levels. These are the classical levels. You have this thyroid trichoid, and of course, you can actually see the upper trichia. You can actually palpate, and you can, so you have these levels. So this is what we are. Now I'll just show you a video of the operative steps and then highlight all the points in the operative steps. So there's a single, there's a copectomy here, right? And there's a compression, right? Two-level compression, because not only one, but two, but you see the cord, it's completely narrowed here. So we just did it. So now a small, very small incision. You don't need a long incision because you can actually undermine the edges, and you get a very good space there. You seldom have to use a vertical incision. Seldom have to use, horizontal is enough. The important thing is that, you know, platysma has to be, you know, excise. You must make sure that you have undermined it adequately. Then you get a huge space there, huge space there, right? So that's the second step. Define the sternocleidomastoid, palpate the carotid artery, you know that, right? So you palpate the carotid artery, and then just medial to that, tracheostefil space. Now here is the importance of an anesthetist. So if he's your friend, then he will give an adequate relaxation. And when you are putting those retractors there, if there is adequate relaxation, then the patient will not develop any dysphagia or hoarseness of voice, you understand? And the second thing is to actually go quite above and below, and create space between these muscles, tracheoesophageal muscles, the paratracheal muscles, and between the sternocleidomastoid and the carotid sheet lactally. Create adequate space, and then open the pre-vertible fascia and see for both longest coli. So now here is the importance of the midline, because if you have an OPLL, you will not do a total job unless you define your midline, right? So here you must actually define the longest coli and just create adequate space for yourself. There's another reason why you need to create adequate space for yourself. If you have adequate space for yourself, when you're putting your retractors, then you don't know how much pressure there is on the tracheonisophagus. And if the relaxation disappears, then there's going to be a significant pressure without your even realizing it. So now you see both these bodies define them, localize them. And once you do that, make sure that you are in the midline and then you start doing it. When you're drilling, you don't worry about the bleeding. All you have to do is to have to create a gutter which is a minimum of 1.8 to 2.5. That's the range of the gutter. And make sure that you have pillars on opposite sides. This is very important. And make sure that you are beyond the disk spaces on both sides. This is very, very important because you might leave a little bit of osteophyte or a disk above and below. And then, of course, and the depth, there are two ways of assessing depth. One is go on doing a dyssectomy. When you're doing a dyssectomy, you know your depth. You know your depth. Every time you reach a point, go do a little more dyssectomy. Go to the next step. The other way, what is the other way of doing it? As soon as the trabicular bone disappears, you will get an absolutely white cortical bone and the bleeding disappears. So then you know you are almost reached the dura. And then, of course, you just put in a graft and the plates. And the principles of putting the plates I'll just explain in a minute. So then the whole thing has to look absolutely bloodless later on. And please, please, please, I mean, I'm very conservative about this, but put in a drain. Because you don't know that one patient who develops a small collection here and develops certain respiratory distress. And if your resident is not sharp enough, he's going to miss it. And you might lose that patient. And especially with a long segment of equipment, it's always better to put in a drain and just take it out the next day. Now, there are two issues associated with just putting a graft without putting in a plate. One is that there is graft subsidence over a period of time. Now what is graft subsidence? What happens is that the edges, when you remove the cortical bones, then it kind of compresses itself on the graft. And the graft goes into the vertebral body. So that's known as graft subsidence. And that takes place over a period of time. Now the problem is that this plate helps in load sharing, which means that a part of the load is transmitted from the graft that you have in the center. And part of the load is transmitted through the plate that you have on the side. So that helps in load sharing. And that is why, even when you have done a very good grafting there, you need some kind of load sharing equipment by putting in a plate. The second very important thing is that try and not put rigid constructs, which means what is a rigid construct? Rigid means you put in a screw and it stays in place. It doesn't move out. Now the problem with that is that if this is not wide enough, this is not wide enough, many of the local companies will make those rigid ones which do not move up and down. When there is graft subsidence, what will happen is that the screw does not have the ability to go up and down with the subsidence. So what happens is it loosens. You understand? Then of course, what are the complication avoidance methods of the problems that you face? Of course, tracheo, you see the recurrent laryngeal nerve and superior laryngeal nerve. What is the best way to avoid this complication? Don't see the nerve. Don't see the nerve. So you don't see the nerve. So you know where it is, but don't see it. So that's the best way to. And then, of course, vertebral artery, I've already told you. So two places where the vertebral artery can get injured are here. So it's actually quite in the middle, not quite lateral. Not deep down. It's quite in the middle. And then neurological injury. One is as soon as the trabicular bone is over and the cortical bone becomes old shiny. So that's when you need to change to a diamond drill, plenty of irrigation so that that's where you shouldn't cause an injury. And usually there'll be a posterior longitudinal ligament behind, but still you need to make sure that you don't injure the bone. The second is, of course, at the last part, when it's a thin bone, use a kerosene sponge. Now, two common mistakes. One is I've seen people, they don't make the bone thin enough, and they use a larger kerosene sponge. The head of the kerosene sponge has to be the smallest possible. So what you're doing is only removing a very, very thin transparent shallow bone without any effort and you're not putting the foot of the kerosene sponge deep into it, because that's where you cause injury, especially the nerve root injury. That's where, you know, there's a sudden monopyrus or something is because of that. The other very important thing is, this is a very, very important point. This is not a usual disk situation where it's a soft disk and you can just remove it. But if there's an ossified posterior longitudinal ligament and there is an asymmetrical ossified posterior longitudinal ligament, what happens is that at one point, there's a lot of compression and on the other point, there's less compression. And if you're drilling uniformly, if you're drilling uniformly, what will happen is that soon at the point of less compression, the dura will prolapse out. Once that prolapses out, then it is impossible to reach the point of maximum compression. So read the radiology, go to the point of maximum compression first, make it uniform, and then come to the dura. This is very, very important because with OPLL, this is a big problem. You know, all those people who are experiencing OPLL will immediately identify with what I'm saying. The other very important thing is you make the gutter too narrow. This is a very, very important problem. You make the gutter too narrow and the bone doesn't fit and you can't go in. Make sure your gutter is wide enough. A wide gutter is very, very good. It's very easy to do work with a wide gutter. Never work with a very narrow gutter. And the third point is that if in an OPLL, you find that the bone is not getting removed from the dura. Either you can remove it with the dura and then put in a fat with a febrile glue and put a bone graft over it that is one way, or the other is you just leave a little floating bone there. Just leave a floating bone there and that works very well. But usually you remove the bone because sometimes it gets ossified again. So it's much better to remove it than not to remove it. But if it is not getting removed, just leave the floating bone there. It works very well. Now, what are the communist problems which cause plate extrusion? One is that you keep the plate away from the vertebral body. This is the communist. Because what happens is as soon as you keep it away, the screw loosens and this comes out. This is a very, very common problem. The second is that when you actually put the screw is directed downwards. It's always a compressive force there. So that plate is providing a compressive force. So they have to go up and they have to go down. Is that clear? These are two very, very important reasons why the plate. And the third is that the length of the screw is not adequate. So it has to be of adequate length that it reaches up to nearly the posterior mass. So you have to measure all these things beforehand. The other thing is graft extrusion. Common problem. In your mind, what do you think are the common causes of graft extrusion? So one important thing is, see one very, very important thing why it comes out is that you try to take a very long length. Just don't do that because what will happen is you artificially try to force it into. And as soon as the patient flexes a little, it kind of comes out. So the very important thing is that the length has to be just right. So that you put it in place. Just snugly fix it into place. That's a very common problem. And the second is the width is not enough. When the width is not enough, then it's a very narrow thing and you try to either it breaks or it slips out. These are two very, very common problems by way. These are very simple problems but they are very common. And the third very common problem is that it's not a trichortical graft because it will not providing strength. So it will break. It will get fractured. So these are three very common problems which are responsible for this. So you see that this is an OPLL here, right? And this is how we went. And we left this, okay? Yeah, we left this huge thing there, right? And this is a classical point. So you must know where the midline is and if you're working from one side, you will naturally drill on the opposite side. You'll naturally drill on the opposite side. Another very important thing is disphase your hoarseness. Your anesthetics is not your friend. You know, proper relaxation. You won't know because you know the thing is under the tractors, the whole trachea isophagus on one side and on the other side. So that is fun. You must make sure that they're adequate relaxation. The second is adequate exposure because what happens is sometimes you have not exposed vertically adequately and then you're trying to pull. So just dissecting between facial planes makes a lot of difference to reach the point. And like I told you, you need a trichortical graft there. Finally, the last two points that I'd like to mention. In a child, when you think that the child is lying supine postoperatively and you don't want the child to be having a position of flexion of the head because you know, that's the worst position for patients who have some kind of cervical problem. It's very, very important for you to understand that there's a disproportion between the head and the torso. And the head is larger than the torso when a child is less than nine years of age. So even when you're putting a child supine, there is flexion of the head. And so what you need to do is to elevate the body a little so that the child is actually in extension. This is one important point. Any craniovertebral junction, any cervical spine, you must remember this fact, especially in a child, right? The second very important thing is immobilization. I'm sorry for this slide, but this is a very, very precious slide for me. So in 1977, there was this guy called Jackson who actually looked at all the external orthosis and the degree and the freedoms of movement which is provided by each of them despite placement. And you will be surprised to know that with a Philadelphia collar that you put place, it's almost 45 degrees of movement are still permissible by a Philadelphia collar. An external occipitomandubular brace still provides 40% of movement. And a four-pose brace still provides this movement. So the only two...