 Okay, so let's start. How many of you have put an Odentoid screw? Okay, so this will be something different, which you haven't done before, most of you. So if you have read the book, it says that the Odentoid fractures are of three types. One is just the tip, which is very rare. I have maybe seen one till now. But the book says that this is the type one. Probably it's just the tearing off of the ligament on top with a small chip of bone. But this is a rare thing. The most common thing you see is at the neck, because if you imagine this is the head of a person, this is the shoulder, then this is the neck. And that's why it's called the neck of the Odentoid. If the fracture runs through here, it's type 2. And type 3 is more on the chest of this person. When it's gone through the body of C2, then it's type 3. And then different people have classified type 2 in different ways, A, B, etc. But basically you need to remember most things about this, because this usually the management is non-operative. You just give him a collar, it should be fine. This is also, you need to stabilize the neck. 9 times out of 10, you don't need any surgery for this. So this is the one which can be tackled surgically. Lot of literature, Odentoid fractures was in fashion about 15-20 years ago. And a whole lot of people have published a whole lot, one screw, two screw, this way, that way. One thing is that the incidence has been rising. Maybe because we are getting more wheels. That's why we have more high speed accidents. And that's why we have more fractures of the Odentoid. Earlier, the management was also not good at the accident side. So more and more people are surviving and getting into the hospital in a better shape. Getting investigated better. And that's the reason why we are picking up more of the Odentoid fractures. Young, mostly motor vehicle accidents. Mostly it's a hyper extension injury. Or the second bimodal peak is you see in old people, 80 years old, 85 years old. And as our population ages, we are going to see more and more of this. And this is going to be a problem because we don't know how to manage this. In an 80 year old with an Odentoid fracture, what do you do? In children, it is less devastating because the ligaments are lax and generally that area can have more space and more tolerant to shifts. And so the results are very good. Whether you fuse from the front or the back, the results are very good. Or if you don't fuse at all. So it seems that the fractures which happen more or less coincide with the embryology. Because if you remember the embryology, the tip of the Odentoid processes from the fourth occipital sclerotom. So the first type of fracture, this probably it fuses later. It becomes solid bone much later so the fracture can occur here. The rest of the denses from the second cervical sclerotom, this one. And there are five ossification centers and the whole thing fuses by about seven years. So you must remember these things. You know the vasculature, anterior and posterior descending arteries around the Odentoid process. They are perforators from the carotid. And because these vessels get disrupted, there are very high non-union rates. What if you don't do anything? What will happen is there will be non-union. And non-union can be a cause of continuous or intermittent but disabling pain in the neck. So to get over that somebody thought why not fuse it. And that's how the operations for the Odentoid process fractures became to be popular. So we have gone through this. So A and B is basically anterior and posterior of type 2. We have been through this how to fix. Type 2 is the one where there is some controversy. Whether you need to reduce and fix anteriorly or reduce and put a halo. Do you excise the Odentoid? If it has gone back and it is not reducing or you do a posterior fixation. But type 3 usually you can get around the surgery by putting a halo and waiting till the body fuses. So before the 80s not many people were operating on the Odentoid fractures. And in 92 Apfelbaum was one of the earliest ones to report actually the anterior Odentoid screw fixation. And he said it's the better way you can immediately mobilize the patient. No need for a collar and everything is fine. And he published a big series I think 160 cases or something like that. So what happens if you don't put a screw or don't stabilize it? The risk of failure is 21 times higher than surgery in patients more than 50 years. That was what was seen. What this means is non-union and non-union means continuous pain or maybe some other problems if it is mobile. And this was published in 2000. Then came the controversy about whether you should put one screw or two screws. But it has now been almost conclusively proved that one screw is as good as two. And in most part of the world the Odentoid is not as big that it can take two screws. And biomechanically it is proved that one screw works as well as two. So the fusion rates as well as stability is almost the same. There is no difference. And technically putting one screw is easier because the Odentoid thickness is not much. All these things we can discuss but we are going to concentrate on the anterior screw fixation. The most important advantage of this anterior screw fixation is that it gives immediate stabilization. The two pieces separate you put a lag screw. How many of you are from have got any touch with orthopedics? Do you know what a lag screw is? So it is not a fully threaded screw. So the first part of the screw is like a nail. And it is only the tip which has got threads. So the theory behind it is that the distal fragment is caught by the threads and the nail gets it together. That is the purpose of a lag screw. So Apfelbaum was an orthopedic surgeon or he was heavily trained in orthopedics if not a... I think he was professor of both orthopedics and neurosurgery. But he had a big orthopedic training and that is how he said lag screw is what we need in this. And so if you put a lag screw then you reduce the fracture. It keeps the whole thing together and it gives immediate stabilization. That is the biggest advantage of an anterior screw fixation. And the second advantage is that it is easier than the posterior C1C2 fixation. He just spoke about posterior fixations. You have to keep track of whole lot of things. The vertebral artery, the root, the cord anteriorly the... But here anterior screw fixation is much less complicated than putting a C1C2 fixation from the back. So we can skip all this. We know this high failure rates if you conserve. And look at the difference in the fusion rates. 40% is the lowest. Here the lowest is 90%. So it definitely fuses. You have to assess whether fusion is the treatment you want. As long as fusion is the treatment you want then anterior is better. You are giving you better fusion rates. So which one to do anterior or posterior? We know the disadvantages of posterior surgery. We have just been through that. But still if you cannot reduce the fracture, if the odontoid fracture cannot be reduced, the two pieces do not come in an anatomical position. Then you cannot do an anterior screw. And then you have to do something posteriorly to stabilize. And we have been through those procedures, what you can do. So reducibility is a sign con on for anterior odontoid screw. You must be able to get it in position. If you cannot then you should not attempt an anterior odontoid screw. Which patients to do? So all patients with type 2 odontoid fractures provided the fracture is fresh. Why is that? Three months. The freshness of the bone is gone. And if it's a hard bone, if it's a cortical bone it's not going to fuse. So then your screw is going to break. Every screw will fail if it doesn't fuse. Remember that. Every screw will break if it doesn't fuse. And if you put in a screw in a fracture which is old, which has got cortical bone or some soft tissue stuck. Many times there is a soft tissue. Fibrosis is growing between the two fractured ends. Then your screw is not going to heal the fracture. It's going to break. Whatever you can get, I don't believe in one thing, two things, three things. Whatever radiology you can get in a patient, please get it. MRI is no radiation apart from a little bit of money. And if your hospital can afford it, get an MRI in every patient. You'll at least know what's happening to the cord inside. But orthopedic people, you know, they are very reluctant to get an MRI done for some strange reason. But we should know what is happening in and around that whole area, including the cord in that area of the cervical medullary junction. We have been through this anterior and posterior. So here is an example. You can see the fracture. So this part has gone anteriorly. And that's how this is the one which is causing the pressure now. So if you cannot reduce it, you cannot put a screw. The odontoid screw is supposed to go from here to the top of odontoid. Your odontoid is here. So you obviously cannot put a odontoid screw in this case unless it reduces. So you pull, you give traction, you extend his neck, you do whatever maneuver you think is right depending upon the nature of the fracture to try and get it in line. Unless it is in line, you can't put a screw. Even this is not perfectly in line. So this is not perfect for an odontoid screw because the screw will start somewhere here and it will go this way. So it will take very little portion of the distal fragment when your screw is going to fail. This is not an ideal position for putting a screw. Why is it so? Because look at the fracture in the cross section. It's an oblique. It's placed more on one side. It's an oblique thing. So your screw is not going to work here. So you must be very careful and look at the anatomy of the fracture and decide whether your screw is going to do the job or not. Now sometimes it moves back, like in this patient. The odontoid is moved back. If you see the C2 body somewhere here and this whole thing has moved back and the C1 is shifted back. So again, reduction. If you don't reduce it, your screw is going to hang in mid-air, go into soft tissue somewhere here. So reduction is important. Once you reduce it, once you get it in a nice position, then you can put a screw properly. Another thing is that you need two x-rays. You know, you need to keep looking at the screw where it's going in an AP as well as in a lateral direction. So it becomes a little fiddly. So you have very little space to stand, the surgeon, the assistant. There's the traction there, the endotracheal tube and all the paraphernalia of the anesthetist. On top of that, you have these two x-ray machines. So sometimes it can be tricky. But if you have only one machine, even then it can be done. You keep shifting between AP and lateral and then the surgery becomes longer because every time you need to change to lateral, AP, lateral, AP, so it's difficult to reproduce the exact image again and again. A few centimeters the machine shifts, you may not get the same image again. So that's the trouble. So it's best done with two x-ray machines, which is difficult in many operation theaters. Have all of your operation theaters, have two x-ray machines. So with one machine, it's very difficult to do that. You'll spend a lot of time looking at AP and lateral again and again and just moving the x-ray machine. And by the time you're through, you're so tired and you're sick of the whole thing that you don't want to do or don't want to do it's screw ever again. But if you have two machines, then it's nice. So that's what you should do. So you must look at the CT, x-ray, MRI, everything carefully to decide whether this screw, this is what I mean by the lag screw. You see, only the tip has threads and the rest of it is a nail. That's how this tip pulls the disc fragment towards. It reduces the gap between the two fractures and that's how it's going to hold it in opposition. Fusion needs tension. If there is no tension between the two pieces, it's not going to fuse. It needs to be opposed. That's where you begin. So you might have to remove a little bit of disc anteriorly between C2 and C3 so that the head of your screw goes into the disc space like that. And you see the angle? That's the angle. So all this is soft tissue here. So just imagine where your skin incision is going to be. This is 2, 3, 4, 5 or 6 maybe. So your skin incision or where your angle touches the skin is going to be at C5, 6. So that's where you should begin. That's where your incision should be. That's where your exposure should be. And you should start dissecting from there. You go up till you get to this C2, 3 disc space. Then you'll give a small incision in the disc, remove some part of the disc so that you create a space for the screw head to lodge. So it should not protrude out because that's where the trachea isophagus everything is here. So it's going to obstruct. If you start here, the screw is going to project to the soft tissue here. That's not good. It should lodge inside the disc space. So to get that angle, you need to begin lower down. And it depends upon each patient. So you'll have to do an x-ray on the table, place a metal instrument in this angle and see where your skin incision is going to be. And that's where to begin. So that's where it should be. Right in the middle. Now what's wrong in this? One, it doesn't seem to be reduced there. I don't know. I can't see properly, but there's probably still a gap over there. And second thing wrong. Yeah, the head of the screw is not inside the disc space. It's lodged here. Third thing which is wrong, it's not taken the anterior cortex. I can still see the anterior cortical line here or probably here. So there are many things wrong in this screw. Still, it is probably one of the earliest ones you see. I don't think this machine exists in our routine now. So this x-ray must be at least 15 years old. We were very happy because the thing fused ultimately and the patient was fine. But there are so many things wrong in this. So I always put this to make sure that you know where things can go wrong. The result may be good, but it's not a good, it's not a well-placed odontoid screw. The head is not in the proper position. The tip is not in the proper position. And the lag effect is not there because your threads are still straddling the fractured part. That is the most important thing, why the gap between the fracture is not reduced because the whole lag effect has not come. This screw needed to be longer and the tip should have been somewhere here. So we looked some of our patients. We did it in 80 years, but now it's a controversy. People believe that maybe it should not be done, but still. Usually it doesn't cause much problem. Odontoid fracture patients come with just the complaint of cervical pain. Most of them don't have any neurological problem. Most of them, because eight of our patients did have cortiparesis. And that's why the MRI becomes important. If you have an odontoid fracture patient with complaining of neurology, you must get an MRI done and see because most of the time the odontoid fracture should not be causing any neurological thing unless there is a contusion inside or some injury inside. So most of them were one month. I mean we get late, we get patients referred from everywhere and if they are intact, they have to wait in line. So that's why the delay. But the earlier you can do, the better it is and the cutoff usually taken is three months. If it is more than three months, it's wiser not to attempt an anti-odontoid screw, it will fail. So earlier we didn't have to X-rays in our theatre. So the first eleven odontoid screws we did with, I did with only one X-ray and it was a big headache. It was a big headache. But then finally we had two X-rays and then it was much easier. And then we had image guided also. But frankly I have never used image guided. But nowadays these guys use image guided for practically everything. So what you use is a single, earlier ones we used steel screws, lag screws because the titanium screws were not available. I think the first screw I did when the titanium lag screw was not available. So I used the stainless steel lag screw, four millimeter diameter in the first eleven patients. And now you have all these things, the cannulated stuff available. You can do it percutaneous so that the guide wire then tracks everything. Your drill goes through, goes over, your tap goes over that and the screw also goes over the guide wire so things become much more easier. This can probably be done with a tube. This is one of the surgeries which can be done with a tube and there are some reports available which they have done with a tube. No need to make a big incision and do a lot of dissection. Usually there are no complications. Most of the patients don't have any problem except for the people who have been injured who have a cord contusion or a cord injury before. So they may continue with that process. Most of the patients, one was lost to follow but thirty seven, all of them showed good fusion including the one in which the screw was badly placed. So it's a forgiving surgery as long as you get the two things in proximity as close to each other as possible most of them will fuse and provided they are fresh. In one patient a posterior fixation had to be done because of persistent atlanto-axial dislocation despite good fusion of the odontoid. Odontoid fused but the atlanto-axial dislocation can you think of a reason why that would happen? So that's another reason why you must get an MRI done. No other thing will tell you about the ligament injury except an MRI and this is what happened. I think the earlier ones we did not have an MRI and then this fellow he actually still had AAD the odontoid fused but he still had atlanto-axial dislocation the traction got it in place the screw went fine the odontoid fused but AAD persisted. Immediate direct fixation preserves the normal mobility C1 C2 mobility is maintained high rates of fusion and immediate improvement of cervical pain which is because of the moving bone pieces. So here this screw seems to be better but still it could have been even better I think a couple of turns more and it should have been better and this we can't see it very clearly but I guess it's reached the top. Another one seems to have reached the top or seems to have reached the cortex at the back so fairly in the midline fairly well placed you can see it till the last cut which they showed us I think the one cut above it did not show the screw so it stopped somewhere here but it's gone through the fracture segment and the threaded part is beyond so it worked. So this was the oldest patient we did 80 years old we had a fracture the screw is slightly tilted it's gone off to one side but I think it straddles the fracture line and the distal part the threaded part is beyond the fracture line so it worked very well and he's the gentleman three days after surgery and he was fine and later on the odontoid fracture fused so everything worked out well. This is just a brief overview of the odontoid the obliquity of the fracture is also important that is I think it's common sense if you can see that your screw is going to push the distal fragment away the fracture is in such a way that the moment you touch the distal fragment it is going to push so it's dangerous but you can get around that it's not very difficult to get around that you can put a finger in the mouth you can actually push the odontoid and keep it there till you get it across the fracture and get it into the cortex on the other side and once you do that there's no need or you can use a sponge holder one used for cleaning put a sponge around the sponge holder put it in the open mouth and press the odontoid and see on the x-ray whether that is helping your direction or not there are two or three things you can do