 So, this is a very visually I will take you to the entire spectrum of extreme and far lateral approaches to the skull basin I mean at the end of the presentation I hope that you will understand the differences between the nuances of different types of approaches as well as you will be able to do all of them without any problems I mean there is nothing to do it actually it is just the name which is more important. So, what is the basic aim of the approach you know it is not that you just want to do some stunts there it is not you are not trying to show off what you are trying to do is when you go from posty approach you have the spinal cord in front of you and because the spinal cord is in front of you therefore you are actually not able to retract the spinal cord and go anterior to the spinal cord. So, what you are doing is you either go just anterior laterally or completely laterally and reach anterior to the spinal cord from a lateral aspect which means that you will have to either drill the so you have to drill the condyles there. So, just to drill the condyles you may or you may not I will just tell you when you need to drill it and when you do not need to drill it, but this way you can actually go to the anterior part of the tumor and so the basic thing is that none of them this is from you know theory these are all cases which have been operated and this is completely visual. So, there are no written words there right except of course just to give me a hint that I should not forget those things. So, now of course a little bit about anatomy anatomy is the I used to hate anatomy so, but you know that is what God said when you hate anatomy then you must do anatomy all your life God is taking revenge. So, you know the external occipital patrobrans you know the superior nuclear line you know the mastoid and the mastoid groove here right all these things you know you know the stylo mastoid foreman where is the stylo mastoid foreman now here somewhere here and then you have foreman magnum juggler foreman. So, first I encourage you you know give you tell you the word the anatomy you already know then take you through the complex anatomy. Now, we come to some interesting anatomy you know a bit of this you know that this is the occipital condyle right you know that the hypoglossal canal is in the middle of it. So, from here to here this. So, it will be like this and it will be two-thirds and one-third where is the juggler process juggler process is this piece of bone right. So, this is the juggler foreman and this piece of bone is the juggler process right. So, just these three things which I esteem on ok is not relevant, but juggler process. So, this is very very important and I will tell you why it is important you will understand in a minute right. So, this you all got you located this yes all of you now look at it from the inside. So, this is the condyle this is the hypoglossal this is the where the hypoglossal now comes out and the other important thing is that this is juggler foreman and this is the juggler tubercular. So, there was a juggler process from outside and a juggler tubercular from inside. Now, you can imagine that if you actually rather than coming posteriorly like this if you come like this drilling the lateral one-third of the condyle staying posterior to the hypoglossal nerve then you get an access to the clivus and to the anterior foreman magnum. The only problem is that you have this juggler tubercle which sometimes comes in your way and causes a problem. I will show you real examples of then you know what are the different approaches what are the different approaches to this. So, first is just a far lateral approach far lateral approach means do not touch the condyle just go lateral like this and go anterior, but obviously it means that you cannot go to anterior you can maybe go up to this point, but you cannot go anteriorly that is a far lateral approach. The second is a transcondyler approach what is a transcondyler approach you go like this drill the lateral one-third of the condyle and reach the anterior part. So, one-third of the condyle no instability because the rest of the condyle is intact that is a transcondyler. A paracondyler approach what is a paracondyler approach you do not go to the foreman magnum you go to the juggler foreman and you just drill the juggler process here that here just drill the juggler this takes you to glomus you know for glomus we do dissections in the neck and you do dissections from the suboccipital area this takes you to the juggler foreman by the juggler process and then you go to the supra condyle area which of course is the lateral cliver. So, here by the supra condyler we mean that you actually move like this to the clivers without touching the condyles. So, there is a supra condyler, transcondyler, paracondyler and far lateral is that clear to everyone. So, that is the that is all I mean that is all there is to it now I just show you examples. So, you know you can do it actually. So, now let us go take examples. So, one the first is vortible artery mobilization. So, you will do an extreme lateral transcondyler approach with intra and extradural vortible artery mobilization when would you actually require this let us take this example. So, extensive anterior dural based humors reaching up to bilateral vertebral arteries meaning a meningoma obviously, but it means that it is attached it is not you cannot mobilize it a neurofibroma on the other hand you can you know decompress and mobilize but a meningoma stuck there you cannot mobilize. So, there that is when you want to go more anterior and how do you go more anterior I will just tell you. So, we have a clinical situation where there is a huge dural tail extensive causing cervical medullary compression both vertebral arteries within this meningoma right. Now, obviously I mean somebody says oh I can do it with an endoscope I can do it with a far lateral approach I can do it with a retro sigma approach acceptable I am not saying that I am just telling you the nuances now it is up to you to decide which approach you would like to take. So, it is like you know it is everything the Rajasthani thalis on the platter you can use this or that or that you understand how it is. So, that is how it is. So, this is a thing. So, what is the position? Now, the position is something there is some very small nuance that you really need to know about the position of this patient dead lateral. Why is dead lateral position important? Because if you rotate the neck even a little then you are the relative position of the foreman transorcerium or C1 and C2 changes and therefore, your vertebral artery changes you get it. So, therefore, it has to be dead lateral now whether you make a flap like this or a flap like this depends on what situation you are in. But supposing you want to do a mastoidectomy and all that. So, you would prefer this supposing you want to go up to the midline then you know you though there are different nuances to that, but you can use any of these flaps. Then coming on to this so, you made this and there are three important landmarks the one is external occipital protrusions the second is a C1 posterior arch. So, posterior arch in the posterior tubercle you cannot palpate right now, but then of course, when you are actually dissecting you can actually feel I am sure or C2 spinous process which you can actually prepare and the transverse process of C1. So, this if you go laterally right now you cannot do it, but this can be palpated during surgery. So, these are three important things. So, two structures in the midline external occipital protrusions C2 and the third is C1 transverse process. And then of course, you have different muscles which you need to reflect do not go into details you can reflect them all at one times and it actually helps you in the less atrophy it is better to remove them all in one piece rather than you know to do a piecemeal detection. This is just for your anatomical principles and then what you need to do is to come to the suboccipital triangle. Now what is the suboccipital triangle consists of three muscles at the level of the suboccipital region. So, one is attached to the transverse process going almost up to the midline second from the midline to another midline here inferior midline and the third is from the midline to the transverse process here and the three muscles are supia inferior oblique and rectus corpitis posterior major. I mean you do not have to remember them you do not even have to look for them you just have to understand the concepts. I mean you hardly are able to identify these muscles in real life situation, but you must understand the concept and what is the concept? The concept is that you palpate the transverse process of the C1 right do not worry about these muscles you just process the not the transverse the posterior arch of C1 just palpate which you can. So, go from the posterior to the posterior you just palpate it like that right once you palpate it then where is the vertebral artery in relation to that on the superior border lateral one-third. So, that is all there is the significance of this triangle the significance of the triangle you just do not worry about the muscles palpate the bones palpate the bones palpate the C1 arch and at the lateral one-third you have the vertebral artery right. So, a real life situation this is lateral mastoid this is the external occipital protuberance here and once you have retracted all your muscles in one piece you will have a triangle and do not worry about the triangle the only thing is you palpate the C1 arch here posterior to C1 right. So, this is just what you need to do is you can do it easily everybody has done it. So, it is not it is not something very difficult then what happens is this is the arch of C1 the hint that you are actually going to the vertebral artery is by two nerves the C1 nerve and the C2 nerve. So, you can you will clearly see the C2 nerve you will clearly see the C1 nerve and the other thing is the superior border of C1 which will take you to the vertebral artery is that clear you will clearly see this I will show you. So, what happens is when you are actually dissecting it you see the this is the posterior arch of C1 this is the edge of C1 you can actually feel it going there dissect along the bones you can see C2 going up here and vertebral artery will be somewhere here which you right now do not know where it is right and this of course is the mastoid. So, this is how it will actually look but it is not difficult at all just a simple thing we have all done it did the section we have all done right. Now, what happens is you drill it from the foremen transversarium I will tell you the operative steps in the next one I just wanted to do the first one is just mobilization. So, what is the significance of this the significance of this is that when you have taken out the vertebral artery from the foremen transversarium of C1 and sometimes also of C2 then you see and you have retracted it downwards then what you get here this portion is the occipital condyle. So, this is the sub occipital this is the dura this is the spinal dura and you can feel the condyle here and drill it. So, what you have done is you mobilize the vertebral artery which was like flat like this and coming like this and then going intradural here rather than doing that you have mobilized it downwards and medially and therefore, you get access to this portion once you drill this portion then what happens is you are working significantly anterior to the spinal dura you can well imagine this is that clear to everyone you understand. So, this is the significance of vertebral artery mobilization right and once you have mobilized you have drilled it and you open the dura you see this is the spinal cord and the cervical medullary junction and this is the tumor right. So, you have directly reached the interface between the tumor and the cervical medullary junction without touching the spinal cord otherwise you would have had to go from this aspect and you imagine that the spinal cord is between you and the tumor here is that clear is that clear to everyone yeah. So, just the small thing and after the tumor is removed you leave a dural cuff here and this is the cervical medullary junction you see the color has changed. So, this is the pink color which is in the foreman transversarium this is a red color which is on the C1 arch these are natural there is a dural cuff here and this becomes intradural here and this is the cervical medullary junction you can remove the entire thing. So, you can imagine you can see the contralateral vertebral artery also you can actually see the contralateral vertebral artery also right. So, this is the post operative. So, now what you have done is this is the condyle preop and what you have done is you have drilled a little bit of the condyle here and actually gone anterior to the core right see here you have drilled and gone anterior. So, now we go to the actual operative steps right. So, this is this huge tumor that you see now this is this is a significant tumor right and this is all anterior to the cervical medullary junction. Now, what are the operative steps? So, up to this point everybody can reach up to this point everybody can reach this is the suboccipital region you can see the vertebral artery you can see the C1 nerve root going like this and this is the C1 posterior arch just here do not use monopolar just follow it and use a periosteal disector. So, once you will go along the entire border you will definitely see part of the vertebral artery and you can see the C1 clearly. Now, what happens is the vertebral artery goes like this and then it goes through the fermatransversary and down and here there are lots of paravertible venous plexus do not let them deter you because it is very simple to actually dissect it from there what you can do is you can leave a little bit of tissue all around the vertebral artery. So, that it does not get thrombosed and then go on dissecting coagulating dissecting coagulating do not actually come to the vertebral artery take a lot of tissue along with it. So, that it does not get thrombosed just a small trick you understand and when you are beginning your surgery for this work from the side of the non-dominant vertebral artery. When you work from the side of the non-dominant vertebral artery if it is a midline lesion then the advantage is that even if something happens to the vertebral artery is not a problem at all yes. So, this is just small tricks to you know help you. So, now the next step is you have actually dissected out the entire thing you have traced it right up to its entry into the formant transversarium here. Now, it is very simple to just expose this and drill this part and using a diamond drill it is very simple to do it there is no problem at all right just do it. And the next step is that this is the drilling just drill vertically down and after you have drilled it you have actually seen the entire thing from here to here yes. So, you have seen this going like this going like this and this is where the condyle is this is where the condyle is okay. So, once you drill this condyle then this takes you anterior to the cord here right. So, you have drilled this and this so now it has become completely mobile. So, this is where the dura is there the posterior has been removed. So, it was horizontal like this and going vertical like that now all you have done is to mobilize it and turn it downwards when you have done it what do you get? You get this whole area here which you can drill and once you drill that you reach anterior to the cervical medullary junction is that clear? And then you open the dura once you open the dura what do you get? You get a lot of low cranial nerves and you get the 11th cranial nerve the accessory now spinal accessory now. So, this is the cervical medullary junction this is the cerebellum this is where the tumor is and this is the erecnoid over the tumor right. So, imagine because you have drilled this much of bone you are actually seeing from here otherwise you would have seen from here you understand the difference are you getting the difference? So, this is how it is the difference between going that way and this way and then when you open the erecnoid you can see the tumor anterior to the cord here and then of course with intertumoral decompression and preserving all the cranial nerves you can work anteriorly and go on mobilizing till you remove the tumor then it is possible to just coagulate the anterior margin and see the opposite vertebral artery. You can actually see the opposite vertebral artery mobilize the entire tumor here and this is so this is the cerebellum this is the cervical medullary junction this is the area which was created by the tumor and then finally you have the postoperative where you actually have been able to go like this to the anterior part of the cord simply because you have mobilized the vertebral artery right. So, now you have this it is not always necessary to mobilize the vertebral artery sometimes supposing you have a tumor like this which is a recurrent tumor where the vertebral artery was already compromised then all you need to do is this extensive tumor you take the same approach do not worry about the vertebral artery just take out the entire part. So, it is not necessary that every time you need to mobilize the vertebral artery you need to do all these things and so here you find that the contralateral artery was well preserved and the ipsilateral artery was already had already been ligated and therefore what you needed to do was complete removal just by this approach without without actually bothering about the vertebral artery in this case right. Now transcondental approach without vertebral artery mobilization so you have this patient who had the subrecnoid hemorrhage and intraventricular hemorrhage and when you see this angiogram you find that there is an aneurysm which is quite low down almost at the level of the condyle and this is arising from the pica right. So, there is a pica aneurysm so this is the condyle there is a c1 arch and there is this aneurysm lighted the foremen magma right. So, this is this aneurysm pica and why was not why was not this embolized you will understand when we did an angiogram what did we find we found that this is the basilar artery this is the vertebral artery right and so there was a dissection in the basilar artery so the basilar artery was not filling this is the dominant pica and there was a dissecting aneurysm of the pica here and this pica was bio hemispheric so the dissecting aneurysm was arising from a bio hemispheric pica and there was this solitary basilar artery which was supplying both the posterior cerebral arteries arising from the vertebral artery is that clear? So, they said no question we cannot go into it right. Now, this is quite lateral this is situated almost at the level of the condyle here this is a bio hemispheric pica and this is actually a dissecting aneurysm here and basilar artery is filling up very very little right. Now, this is quite lateral dissecting aneurysm so here again the same approach. So, this is superior this is inferior this is C 1 arch like I told you but you will always get this you will always see vertebral artery just superior to the C 1 arch here right. Then drill the C 1 arch right there is no need to mobilize the vertebral artery there is no need to because it is quite low down and so there is no need for a all you needed was a this vertebral artery is quite low down what you need to do is to drill this part of the condyle without mobilizing of the vertebral artery. Once you have drilled this then open the dura and you see that this is a part of the cerebellum this is a part of the foremen magnum right. This is the vertebral artery this is the dominant pica and this is the aneurysm. So, you imagine that by just drilling a little bit of the condyle you have actually come quite anterior to the cord you are actually seeing the complete aneurysm here you just reset out the and this is the pica. So, this is the dominant pica here. So, just see the entire you have the entire pica in your view then you just secure it and this aneurysm was clipped and the part of it was removed. So, imagine that you have actually reached quite anterior to the brainstem just by this time you have not even mobilized the you have not even drilled the condyle right. Now, when would a only pure far lateral suffice there is no need to drill the condyle there is no need to for vertebral artery mobilization just far lateral approach. So, you have the cystic lesion you have the cystic lesion which is anterior which is a cystic lesion. However, because it is mainly cystic you see that this is exactly occupying the same space with the other tumors were done doing but the point is that this is cystic. So, it is easily decompressible right and once it is decompressible. Therefore, what you do is the same thing you went by a lateral approach but this is the dura this is the cranial part and open the dura and here you can see again all the nerves and the C1 and all these nerves and this is the cerebellum here but this cystic tumor could easily be removed by not drilling anything. So, just decompression and the entire thing comes out. So, this is a far lateral approach right. So, you can understand that sometimes you will need if it is higher up tumor if the vertebral artery is coming in your way then you need to mobilize it bring it down right. On the other hand if there is a lot of gap between the condyle and the vertebral artery then you do not need to mobilize the vertebral artery you can just drill the condyle without mobilizing the and sometimes when you have a cystic tumor which is quite low down there is no need for anything you can just go by a lateral approach. And now this is another pica aneurysm. So, this is another pica aneurysm and this is the this is the pica right. So, this is from the vertebral artery and this is quite lateral. So, this is the midline this is the midline and when you assess the from the midline this is quite lateral. So, this is almost reaching up to the cerebellum pontine angle or the cerebellum medullary cistern. So, here there is no need to drill anything there is no need to mobilize anything what you can just do is this is the cerebellum this is the cerebellum these are the tonsils just retract the tonsils what you see are the low cranios you can see the distal pica right and you can see the aneurysm here. And what is this structure? I told you about this structure this is the jugular tubercle. So, you can see the jugular tubercle. So, sometimes you will need to drill the jugular tubercle to get proximal control. So, here you are not getting proximal control. So, if I had drilled all this area drill the condyle then I would have come anterior like you saw in the previous case here I have not done that. So, all I am getting is a distal vessel and I can see the aneurysm here and this is partially embedded into the jugular tubercle right. In this case I could apply a clip, but then it is dangerous because you do not have proximal control here. When would you not use any of these approaches at all far lateral extreme lateral or anything you have this classical case where you have the significant you know like classical you I will go lateral lateral lateral and then what happened was there is this extradural component. So, there is this huge extradural component means this will give you space a lot of space. So, when would you not use any of these far lateral approaches when it is there is an extradural component, when there is a dumbbell component which will give you enough space when there is a significant lateral component to the lesion. If it is a neurofibroma because a small neurofibroma can easily be mobilized even with a simple approach and if it is cystic lesion like you saw that neurointricist there is no need for any of these approaches no need for it you can just go lateral and remove it right. Of course, we have all these problems the most important problem is low cranial palaces because you know they are working between the cranial so you have to be very very careful about low cranial palaces and the other thing is venous bleeding. So, you must always have some fibrin glue and it is very simple just put a little surgicell with the fibrin glue it will completely stop your bleeding. There is a lot of paravortable venous plexus which may sometimes bleed and instability usually does not occur provided you have not drilled too much of the coxipodial condyle. So, there is no need to do it I mean it is just superfluous to actually do stability there is no need to do it. So, this gives you direct access to the anterior cervical medullary junction you must have it in your armamentarium I do not say that you need to mobilize it in every case. So, just in case you feel that it is anteriorly blaze meningioma which is completely adherent to the dura right and encasing both the vertebral arteries with no lateral component that is when you actually need to mobilize the vertebral artery right. And of course, even the contralateral vertebral artery can be mobilized using this approach is that clear. Thank you.