 I have to talk today about the operative treatment of fractures of the odontoid. So what is the problem here is it is difficult to imagine this bone which you just saw and imagine it inside a human body in three dimensions and then try to put the screw to fix a fracture which occurs commonly over here at the neck of the odontoid here this is one. I remember the first time I put an odontoid screw it was in 1997 or 98 and the next day morning when I put up the picture you know we had to have a morning meeting with the chairman and to show him what you have done yesterday. So I showed the post-op screw and he said oh my god this patient must be dead you have put the screw in the brainstem because it is difficult to imagine where this screw is going in an x-ray especially if you see an AP view of a fractured odontoid screw you will think that it is in the brainstem anyhow because of the complicated shape because it is difficult to imagine there is no disc you know here so sometimes identification is a problem because disc is a very good identification you can go into the disc you can put a needle stick a needle take an x-ray confirm where you are but here there are no discs it is difficult to put something inside and take an x-ray to confirm and there are all these ligaments attached to it the apical which is attached here the ailer they go on the sides and the transverse which kind of holds it together opposed to the C1 arch and stops it from pressing into the brainstem there are many other ligaments but let us not go into that these are some of the earliest reports which I could find on operative treatment of odontoid fractures so way back in 1980 that is 34 years from today so it is nothing new it is nothing new this operative treatment of the odontoid fracture has been around for a long time the report say that the incidence is increasing but there may be two or three reasons and it is a kind of a skewed observation because I think the number of people is increasing the number of wheels is increasing the speeds are increasing the roads are getting better there are more accidents and that is why your diagnostic ability is getting better you did not have CT scans and MRIs before now you have all of these and I think this is just a indication of all that technological advance that the incidence of odontoid fracture at least the pick up rate of odontoid fractures is increasing two peaks you see in the graph one in the young mostly motor vehicle accidents mostly hyper extension injuries and then the second peak in old people more than 75 or 80 years where a relatively trivial injury a fall in a bathroom hit against the tub or the wash basin or trivial injury can lead to odontoid fracture and usually what is seen is most of the young ones have an anterior type 2 and most of the old ones have a posterior type 2 if you see the embryology of the odontoid process these fracture modes generally follow that the tip is from a different sclerotome the fourth occipital the rest of the body of the odontoid is from a different sclerotome and then the rest of the C2 bodies from a different so that is where the commonest fractures occur this one is very rare I have seen only one maybe two and it looks more as if it's the ligament which is gets torn off due to a hyper extension and the tip a little bit of the bone gets torn off with the ligament which gets torn off otherwise it is not much of clinical significance to this type 1 fracture it is just there in the books I've never seen it maybe once or twice most common is this where the odontoid gets fracture at the neck and this is the one which we deal most commonly sometimes this fracture may extend into the body it may be a complicated fracture in the shape of an X Y Z all kinds of things or it can be a like a necklace extending into the body and some people have been kind of pushing the envelope trying to fix the fractures in the body as well but for the young people I won't advise you to do that don't push the envelope stick to the book stick to the the classical teaching only type 2 need to be fixed anteriorly this you can leave it when you have white hair like me why does it happen why do we need to fix it because of the vasculature you know they're kind of end arteries which supply the odontoid process and in a fracture they get disrupted and so there are the very high non-union rates even if it is not displaced it won't fuse and sometimes it gets distracted or move anteriorly or posteriorly and then it doesn't fuse and if it doesn't fuse it's going to cause chronic pain in the neck literally and that's why you say pain in the neck I think it came from non-union of odontoid fractures anyhow so that's the reason why we feel the need to fuse this so that that pain in the neck goes away if you don't do it it may lead to non-union classification we already know so type 1 just the tip type 2 at the neck type 3 the body's involved simple basic classification very easy to remember 2 can be divided into 2 a and p anterior if it gets displaced anteriorly posterior p I think this is a very good working and a simple classification for day-to-day management of these fractures this should suffice there are other classifications available but this is suffice how do you manage them type 1 if there is no instability and usually there isn't it's just the tip and it's so rare that you'll probably see once or twice in your lifetime just a caller for three months and it should be fine type 2 there are many things which have been described in literature you reduce and you fix anteriorly with an odontoid screw you reduce and you put a halo and wait till it fuses you may have to excise the odontoid if it is gone posteriorly pressing on the dura or pressing on the brainstem or the cervical medullary junction and it is not reducing sometimes you may have to excise it or you have to go from the back you go open the joint distract it try to pull it forward reduce it basically you have to reduce it if you don't reduce then the problem will remain that is one way or only posterior fixation or a transarticular screw there are many ways to fix it and type 3 usually the classical teaching is reduce try to get it back in position as close to normal anatomy as possible and put a halo wait three months any fracture will fuse it should fuse unless there is some soft tissue trapped between the two fractured elements and then it's going to be a non-union so before 85 everybody was putting a halo where nobody was putting any instrumentation for these fractures I think one of the largest and the oldest report was apple bomb in 92 I think he published 162 odontoid fractures with the anterior odontoid screw fixation and very good results so that I think renewed the interest in the surgery all over the world and since then there have been many series so there are some controversies with it why I explained to you the non-union and some people have actually studied compared people who have been put on a halo to people who have an anterior screw fixation and they found that the risk of failure of halo is 21 times higher than surgery if the patient is more than 50 years of age so it's not that halo is an answer to all there is a failure rate and significantly higher than an operated patient one screw versus two screw I think it depends upon the anatomy all my life I've done one screw and it has worked very well but if you have a big odontoid process if it's a seven foot or six foot eight inches man with a big odontoid process maybe you can get two screws in because the one screw may not give you the rotational stability which two screws provide but if it is a thin odontoid a small person one screw is good enough and this has been studied and written up and proved that the pullout strength and fusion rates and everything is the same there is no difference between one screw and two screws putting two screws in the odontoid can be tricky it can be difficult one screw works equally well we have seen all these now let's see what happens after rigid externally mobilization like I said 21 times higher rates of non-union especially if the patient is more than 50 years of age and there are so many reports to show 42% 50% 77% 91% doesn't fuse so if you can reduce it and fix with a screw either from the front or the back that definitely has better results than putting just a halo again the same thing and the fusion rates after surgery most of the reports the lowest fusion rates are around 90% that's very high compared to the failure so if you know how to do this operation your patients will be happier what about comparing anterior and posterior which one to do there are some disadvantages of the posterior surgery there is significant reduction of head rotation if you immobilize the C1 C2 joint this movement will definitely go because this happens at the C1 and C2 joint you can imagine what's the problem if you stop saying no you know saying no is very important even for a surgeon even for a spine surgeon you must learn and never forget when to say no and if you do that your patient is not going to be able to say no yeah so there's a significant reduction of that very important rotatory movement of the head and C1 on top of C2 you need to dissect muscle you need to expose the joint you need some bone graft either you cut off the C2 spinous process or you harvest bone from somewhere but you need some bone to fill up that joint so there is one extra scoop involved extra bone involved and you need to wait till it fuses you need to immobilize otherwise it's going to move so some collar or some some kind of restriction of neck movement is indicated but there are some patients in which you cannot do an anterior odontoid screw you have to do a posterior which are those patients irreducible if you cannot get the two pieces together you cannot put a screw through one into the other as simple as that is no complicated science involved in it it's not rocket science it's not neurosurgery if you can't get the two pieces together you can't put a screw from one to the other and very old fractures if the patient comes four months after injury apart from these contraindications all patients with type to odontoid fractures which are less than three months can be operated whether they should be or not is a clinical decision it's a clinical judgment it cannot be on a book you have to see the patient you have to see the x-ray you have to see the picture and you have to decide but apart from those two contraindications every fracture odontoid which can be reduced and which is less than three months can be fixed with an anterior odontoid screw you need to study all these things at least in the beginning when you are still learning it took me years to understand the anatomy and imagine it in my head imagine what it looks like actually inside the body because in the body you just see the posterior element or if you're going anteriorly you don't see anything because your incision is somewhere at C5 and 6 and you've kind of made a tunnel on the vertebral bodies and you reach C2 3 will I'll describe the technique now so looking at the x-ray again and again and again looking at the CT looking at the reconstructed images when we started off there weren't any three-dimensional reconstructions in the CT scan it was just a CT scan either axial and later on a sagittal and a coronal but now you have beautiful 3d reconstruction which can actually tell you the exact anatomy as in the patient look at the MRI look at the soft tissue try and look at the ligaments see if there is any other injury all these are important and decide which one is it so that's what it looks like you know there is a clear cut fracture you can see the anterior arch of the C1 that's the odontoid process so the transverse ligament keeps it together and that's why these pieces this and this stay together while the rest of it moves and it causes some compression on the cervical medullary junction and that's the dangerous part of this operation which is rare mind you it's not that all odontoid fracture kill they don't mostly nothing happens but there can be that is the danger this compression on the cervical medullary junction and if you see the x-ray that's what you'll see it's difficult to make out very faint but you can see the C1 this is the C2 this is C1 C2 on one side that's the odotoid process it should have been here which is overlap by the teeth but maybe you can see a margin here some kind of a fracture here so you put him on traction whatever you need to do extension or flexion depending upon the mechanism of injury and the displacement but you have to get the two pieces together if you can't get the two pieces together you cannot put an odontoid screw remember that if this is the only thing you remember you'll do well if you can't get the two pieces together you shouldn't be doing this operation at all okay okay the C2 is here and the odontoid and the C1 has shifted back so this is a posteriorly displaced again you need to put him on traction mobilize it somehow try and get it aligned only when it is aligned can you do an anterior screw otherwise you cannot few more so now what I mean is the 3d CT reconstruction you know you can have these beautiful images which tell you exactly what is happening the exact anatomy as it is in the patient earlier we didn't have it so the operation is a little bit tricky you need to be sure that you're in the midline so you need x-ray in one plane to confirm the midline and you need to make sure that your tip of the screw is directed at the right place at the top of the odontoid process or at the C1 tubercle so you need another x-ray in the second plane so you need x-rays in two planes before you can do this surgery remember that or if you have only one x-ray machine in the OT then you need to do an lateral then again do an AP then again a lateral and again an AP and it is very difficult to reproduce the image especially when everything is covered with sterile towels and you cannot touch anything you will be standing like this and asking somebody AP lateral and sometimes it is difficult to get the same image again so the best thing is to have two x-rays two image intensifies which can tell you about the AP and lateral at least in the first few cases you must have this and that's one of the drawbacks not every operation theater has two x-rays which can be spared for the same operation through and that's the principle you have to start at the disc between C2 and C3 take out a little bit of disc see this surface of the C2 body make your small starter hole here and then direct the drill bit or whatever you're drilling till you negotiate the fracture and you engage this one and this is the concept of the lag screw you know the only the tip is threaded so this threaded part holds the displaced or the fractured segment and pulls it and this one is like a nail so it's a nail and a screw and if you have worked with orthopedics this is a brilliant concept you've seen carpenters do it for I don't know how many years but then the orthopedics people adopted it and it works very well especially in this fracture because if there is a distal segment which you need to pull down and keep it under tension only then it's going to fuse for any fracture to heal you need it you need to be under tension and finally after removing a little bit of disc and exposing this surface of C2 this is what the ultimate result is going to be so you can imagine to get this angle this is the bone this is the isophagus trachea and the skin will be somewhere here so you just imagine where your skin incision is going to be you see that this is the angle at which you are working so this is two three four five six so your skin incision will be somewhere around C6 while your screw is starting from C2 and going up to the orthopedic process so you'll be working at an angle like this you won't be able to see any of this you'll be barely able to see the disc between C2 and 3 cut off a little bit of disc see this surface and the rest depends upon your two x-rays whether you are putting it in the right place or not okay so here is what it looks like and this is the x-ray which I showed my chairman of the department in 1997 and he said this patient must be dead I don't know where the screw is and then I showed him the lateral x-ray also and he said oh So we looked at our this is old data now it's probably 150 I don't know who's writing it up now I think it's 150 patients now so till 2006 and I started in 1997 we had done only 42 most of them were males and the ages were children as well as elderly gentlemen most of the patients did not have this deficit and you see very few people had it most of them were just pain nothing else but pain most of them are anterior as we saw from literature even literature says that most of the displacement is anterior so first 11 patients we had only one x-ray in our operating room we didn't have two x-rays so I had to do AP then lateral then AP is in lateral and sometimes I had to de scrub I had to remove my gloves and go and adjust the x-ray myself to get the exact image back again few millimeters I used to advance the screw and then I used to get scared I don't know where the screws going so but after we had two x-rays then it was much easier so most of these patients have been done with both and all the patients I've used the single lag screw or four millimeter diameter in 11 patients and after that we had this hollow titanium which you can put on a guide wire you know everything can become guided then it makes life simpler when you are sure that it's not going to go anywhere it's going to go on your guide wire so the later patients I think we had done with this lag screw no major complication nothing in fact and we had follow-up data of 37 patients of the remaining five one we never knew what happened to him and four when this was written up four were still very recent just a few months so we didn't have long-term data but out of whatever we could see all 37 had very good fusion with the anterior worldwide screw so fusion rate till that time was almost almost 100% if we consider only the follow-up patients so the advantages of this are immediate direct fixation of the fracture you're dealing with the pathology if you go and fix from the back and you fuse the joint you're not dealing with the pathology there may be advantages disadvantages sometimes you may have to do that but if you can deal directly with the pathology that is the best and here you're putting a screw right across the fracture and causing it to compress and fuse preserves the normal mobility of C1 and C2 which is very important there are fusion rates are very high more than 90% in the lowest reported cases and there is immediate improvement of cervical pain because the movement the moment that micro movement between the fracture segment goes away the pain goes away completely so here is a 32 year old which we had fixed and as you do it more and more you learn now this one is protruding slightly more than it should you know all these minor things these small things but these small things can cause a problem and if it's a thin patient who has a very thin neck it can actually press upon the esophagus of the trachea and it can cause a problem so you have to make sure that the head of the screw is buried completely under the level of the vertical body and it doesn't project out is another example and that's what it looks like on a CT scan if you do a post-op CT it should engage the top the cortical surface of the odontoid the most distal cortical surface otherwise you won't get that lag effect because it's only that when the screw threads hold the cortical bone that you get that lag effect if you're still in the cancerless bone you won't get that lag effect so to get that lag you need to engage the cortex on the distal side of the odontoid and well it should be placed right in the middle hopefully and in this patient it's everything was alright and this is where the C2-3 disc is so that's how it should be another patient before traction once you put him on traction everything looks aligned there is still a gap but it looks at least the displacement which is gone now and now we can be fixed with an odontoid screw and that's what we did and it worked alright and the oldest patient which I had done and now there are other colleagues who do all these things 80-year-old gentleman 15 days old injury no neurological deficit but he was bedridden due to the pain he used to come with his head held like this and used to say it hurts so much that I can't even move otherwise he was neurologically ill and immediately after surgery everything was fine and this spilt is probably because of some muscle plasm and not because of any rotatory he confirmed that so x-ray CT and MRI studied properly understand the anatomy reduced with traction the sine cone on of anti-rototoid screw fixation is reduction if you cannot reduce it you cannot do this operation and the operation has to be based on these two and you should be able to manage suppose the erotoid screw while doing the surgery you realize that you can't do it it's not possible to put the screw either you're not getting the angle or the C2 body for something wrong with it or your screw something is happening it's not going into the right place then you should be able to do the other operation to turn the patient over and do a posterior surgery if you cannot handle everything don't go into it what will you do if you can't do it you have stuck the patient is the same so all rounds you should be able to do everything then only so it's the treatment of choice for acute type 2 erotoid fracture which can be reduced and if you do it properly there's no mobility and there's immediate mobility you can make the patient stand and walk and do everything almost immediately and a single screw is sufficient to provide good fixation and fusion thank you very much