 So, I will just walk you through the anatomy of this area. This far lateral or extreme lateral approach was used to be more common when we were doing surgically with the vascular legions of the vertebral basal system. Since we are no longer operating among these patients, they have become much less common for vascular legions. So, we are doing sometimes this now for tumors basically and for small tumors. For larger tumors, you do not need to do lot of bone removal because the tumor itself had made space and if you enter into a tumor, keep on debulking the tumor. You can easily do a good job without having to retract the neural axis in larger tumors. In smaller tumors, yes, you still need some of these approaches. So, just give an overview of why we need this approach because vascular legions are practically out for every one of us. So, I will just walk you through the anatomy. Basically, if you have a skull, just when we are talking about far lateral approach, you see we are talking about accessing this area from a lateral side. This is the occipital condyle. So, there are various terms used, far lateral, extreme lateral, transcondyler, all those things. Ultimately, your aim is to get to the ventral or ventral lateral aspect of the foreman magnum through a lateral approach. The amount of drilling of the occipital condyle varies depending on the legion. As I told you, larger legions is not really necessary to drill the condyle. In smaller legions, you may have to drill about one-third of it, more than there is really required in clinical practice. So, we will just go through the anatomy of it so you know what important structures come in the way and what has to be added. So, this is what we achieve. We are want to come to this area from a lateral aspect because here it is a cervical medriary junction, the cranial nerve, the spinal accessory artery, the vertebral artery. So, we have to avoid the neurovescuous structures and access this area from a postural lateral aspect. So, I will just show you different images as I have been doing of this area. This is an important structure. So, you have to come to this area without having to retract or touch or manipulate this area. That is the aim of this. There are various cones of regions. This is the occipital condyle. This is what angle a far lateral will achieve. This is what an extreme lateral when you are taken of the whole condyle. I am rarely using this approach nowadays because I do not feel it necessary for any of the legions which I am encountering. Most of the times, you can go right drill or remove the bone right up to the margin of occipital condyle and get there. Rarely sometimes you may have to do a little bit of it. If you are removing less than one-third of it, then no need of any stabilization procedure also for this. If you have occipital removal and you go a little more far lateral, then you can have access to this area. Various incisions have been described. You can use it in prone, you can position also part bench. Incisions, when heroes described with first far lateral approach, he used this incision. He used a lazy S. So, there are various incisions this time. One is you start in the midline, come like this and make a flap like this. Other is a lazy S like this. Other one is you come like this and here you go up to the midline in the middle force. You have to see two area. You have to say that incisions, they are four types of incision. One is one can, if you want to remove this much of bone, you can use a straight posterior midline incision, which is a very good incision because it gives you a no muscular dissection, no bleeding and you can go as lateral as possible if you go just extend your incision above and below. The standard posterior midline incision is very good if you are not planning to drill not all of condyle. So, just extend your vertical superior and inferior and you can go as lateral as possible. The second incision which has used is a, as I told you, a U shaped incision starting in the midline in the cervical spine, going up to the protuberance and curving like this beyond the ear. The routine one which we use is a lazy S, as you like we do in the rato-sigma exposure, but the lower part we go a little more laterally to avoid injuring, down to avoid injuring the vertebral artery, okay. If we go to the anatomy of this region, it is nice to know what muscle layers come in. Normally, when we are operating, we do not see all the muscles, although there are some people who do a stage by stage muscular exposure, normally it goes straight up to the bone. So, usually one must know the anotomy and the muscles which come into area. So, I will just show you what is the normal anotomy. So, this is the sternomestoid, the trapezius, the semisminalis capitis, the sphenus capitis and this most of the time we coagulate this occipital artery. Once you have taken out the sternomestoid and the trapezius are reflected, then you get longismus capitis, semisminalis. Then you come to the superior oblique, inferior oblique and rectus capitis and this is the so-called suboccipital triangle where the vertebral artery is there. This is the occipital bone, the C1 and the vertebral artery passes through the transverse foreman of the C2, then through the transverse foreman of the C1, comes out of the transverse process of C1 and courses along the superior surface of the arch of the atlas before it turns like this and pierces the dura. This part of an anotomy is very important. You must know two things. One, the vertebral artery passes through the transverse foreman of C1. It curves back over the superior surface of the atlas arch. Then it curves back and goes intro medially and pierces the dura. This area is approximately around 1 centimeter from the midline. And if you remain subpareosteal, due to subpareosteal resistance, you will never enjoy the vertebral artery. So when you are dissecting, always dissect from medial to lateral and remain subpareosteal. If you have subpareosteals, you will not damage the vertebral artery. And before you get to the vertebral, there is always a vertebral venous flexes, okay? And this is the facet joint. This is the so-called pedicle, the C1 posterior arch going the transverse process. And this is the pedicle where you put the screws in for when you are doing a transarticular pedicle screw fixation. This is the inferior facet. This is the pedicle. And above this, when you lift up there, you will get the superior facet of the C1. And this will be making a joint with the occipital condyle. So superior facet, occipital condyle, this is the joint. So when you are doing a suboccipital anotomy, you are going right up to here. So therefore, you must know where the vertebral artery is. And you have to come up to this point when you are moving the bone. This is just a diagnostic representation of the same thing I was saying. C1, pedicle of the C1 inferior facet, superior facet, occipital condyle, vertebral artery. This piercing the dura here. And this area is normally covered by ganglia, C2 ganglia, vertebral venous flexes occur there in C2 ganglia. So these are the standard steps. I will just tell you the standard steps. Suboccipital anotomy or connectomy, what are you comfortable with? Exigen of the posterior arch of the C1 atlas, once you have lifted off the periosteum. Mobilization of the vertebral artery may or may not be required. Most often in large tumors is not required. Some people mobilize it from lateral to medial, from medial to lateral. But I do not think it is really required. The tumor itself has mobilized the vertebral artery most of the cases in large tumors. So this is the bone which is, this is the suboccipital anotomy. The C1 posterior arch has been removed. The transverse foramen of the C1 has been deroved. The vertebral artery has been identified. And then you cut the dura like this. The various ways of cutting the dura. Some people like to mobilize the vertebral artery like this and cut it behind it. I normally do it like this only. It is not really required to, vertebral artery can be pushed this way or this way. But normally it is not required to open up the transverse process. You just lift this vertebral artery and mobilize it laterally and cut the dura like this. This is the opposite side, from this way, then you have to cut the dura lateral to the vertebral artery. So there are various ways which were initially traditionally described to on the dura in this area. So once you have opened the dura, this is what you will, the spinal accessory, the vertebral artery, piercing the dura and then coursing like this, originals of paica. So the aim is to get to this area and try to approach the legion from a postural lateral aspect. In normal anotomy, these things come into view, but we are not operating on patients in normal anotomy. We are operating on patients who have tumors here. So most of the times that these things are lifted up and this sex is lifted posteriorly and opposite side. Unless it is a dead anterior small legion, most of the times there is always eccentric legion at this, this place this area a little to one side, this gives you an entry like this. I will just show you what I did was just to show a life thing, I did a category sort of thing. This is the laziest thing I was talking about. The patient has been placed lateral. This operative side is up in the ear. So this is from behind the area, it is important to curve this laterally because if you do a straight dissection like this, when you are cutting going to the muscle area, you can damage the vertebral artery. If you make it lazy like this, then the chances of vertebral artery injury are much less. Because this is the important when you are doing a mobilization of the vertebral artery and you are dissecting superiorly from medial to lateral, the C1. So once you have done all that muscular work, patient is lateral like this. This side is up. This is a suboccipital bone, the C1 posterior arch, the C2. Can you see this? I appreciate this. This is the midline, somewhere here. This is a suboccipital bone, the C1 posterior arch and this is the C2. There was some vertebral plexus here, venous plexus, okay. Once you do a superior side dissection like this, then the vertebral artery gets pushed along with it. But you take out these vertebral plexus, you will get a vertebral artery here. This is a vertebral artery which has come like this out of the foramen of the C1. It is coursing over the C1 posterior arch. This is very important. I mean it is easy to injure if you do not know what you want. So this is suboccipital bone, midline, C1 posterior arch, C2. And this is the area of the occipital condyne. So now we have removed the C1 posterior arch, the suboccipital bone, this is the C2 and this is the dura which is pushed. I think this has become vertical. The photographer has taken it as a different view. This has become straight. This is superior. This is inferior. Same thing you are saying. Suboccipital dura, the dura of the cervical medullary junction up to the C2 is a C2. C1 has been removed. This is a vertebral artery, lateral position only. Same thing. So our aim is to open the dura like this and access from this side. So whatever incisions you give, ultimately the bony exposure has to be this much. Whether you take a posterior midline incision, whether you take a laziness incision, ultimately you have to expose this bone and up to the occipital condyne. The aim is this. Do not go with aims like far lateral, extreme lateral. You must know what you are aiming at. Your exposure should be on one side so that you have access like this. So this suboccipital bone, occipital condyne. Now once you open the dura, you can already see this is normal and not me. There is no displacement. You have seen the arachnoid covering the spinal accessory nerve here. This is the vertebral artery which will be piercing somewhere here. So this is the, you have already seen spinal accessory, some rootlets here, cerebellum. If you can appreciate this thing here, this is the where the vertebral artery is piercing the dura and entering into the canal and then it will be going up. Now you have cut the arachnoid. This is nicely seen. The vertebral artery is seen here going into, this is the paika which you are seeing here. So it is clear with this. So as I told you, we are not normally doing this approach for aneurysms now. We are doing it for tumors and when as soon as you open this, you will find a tumor here and your aim and if you have done this much of the session, this is fair enough. Same thing. I mean this, you can see the vertebral artery here. It has pierced this here and it is going like this. Same thing, vertebral artery, piercing the dura, going into the dura like this, spinal accessory, paika. These are the vagal nerve roots which you have seen here. So this is a good exposure of the far lateral approach. This is what your aim at when you are doing it. This much exposure is required and this sufficient for practically all clinical purposes. I was telling you, normally if you see large tumor, so this is the tumor. This is the cervical medullary junction. This tumor is large. You see, this is the edge of the spine neural axis. So your aim is to enter like this, not necessary to go like this. If you enter like this and keep on removing the tumor, you will ultimately have a total removal or as much removal as you want without having to manipulate the neural axis. Same this pre-op, post-op. So informant magnum as always say larger tumors are easier to remove than smaller tumors because smaller tumors and 3D plates, then you have to manipulate. In larger tumors, you do not have to do any manipulation. You just remain within the tumor. This is one area. Once you should be happy, you see a large tumor, there is a small tumor. So this small tumor, you have to work more and go more later. Sometimes then you may have to do some condylar drilling in this area. So this is just one. I will show you one. This was an interesting thing. Can you make a diagnosis in this? I mean, this is the measures I had and that is what I thought, it is easy enough. But only thing was, these are vertebral arteries. So most of the time, we are operating on benign lesions in this area, whether it is a meningioma or a need of 5 to 100 lesions, I have rarely operated on a malignant lesion. In all benign lesions, the vertebral artery is really not engaged in the tumor. Almost always it is pushed to one side. There may be some lobules on either side of the vertebral artery but it is never really engaged in a tumor, in benign tumors and rarely you will operate on a malignant tumor. So you must remember that the tumor itself has pushed the vertebral artery out of your field. So you have to respect the arachnoid pain and remain and then you will never injure the vertebral artery. This is just the same patient operative photographs I have just shown. Same thing you can see, this is what we already dissected in the cadveric things. The nerve rootlets is the arachnoid covering the lesion. It was a cystic lesion that was easy. The vertebral artery seen here, this is the beginning of the surgery, end of the surgery. So that this tissue has remained like this. We have not done any manipulation of this tissue except open the arachnoid. This is the intra-legional something, some calcification was seen. The vertebral artery is seen somewhere here, spinal accessory is seen. So this is the end of the surgery. So this is how it should like, pre-removal of, open the arachnoid, do intra-tumoral or inter-legional remover. Sometimes you may have to cut the denticulate ligament if you are going to be more below. And then Adyano suggest all the normal structures should be there without having to touch them. Okay. Thank you.