 So, Tyrionocleotomy is not based on the Tyrion, when you make the Tyrional Barrel, it is based on the Tyrion, the Barrel is not at the Tyrion, that you must remember, sometimes you say Tyrionocleotomy make the Barrel on the Tyrion, the Tyrion is not the point, so when you tell your resident because all of you are now seniors, you may be asking someone else to open this skull for you, so where to make the Barrel, you have to give instructions, how will you give that, you cannot say make it on the Tyrion something like that, so what will you tell your resident, what landmarks, bony landmarks are there when you donate Tyrionocleotomy, there are three important bony landmarks, one is always visible superior temporal line, second is lateral margin of supraorbital rim and third is where these two are meeting and with the frontal process of the magnetic bone, so these three meet at a point, so this is the point superior temporal line, lateral margin of supraorbital rim and the frontal process of the magnetic bone, they are meeting here at about half a centimeter below and inferior, that is the Tyrion, that is the where you make the key Barrel, not the Tyrion, so when we see bones are meeting half a centimeter posterior and inferior is where you make the key Barrel, now since I have we have talked so much about the key Barrel, I will just give you one more point which I think is also time has come to talk about that, nowadays almost everybody is using a drill, I mean Giggly saw maybe some people but most of the people have a drill and use it, when using a drill then you have to modify according to your structure, so when you are doing a Tyrion, you have to be using a drill, it is not necessary to make a Barrel at the key Barrel, it is not required because what we do is we make a Barrel leg here, you make one Barrel here, you come like this, come like this then drill this part a little bit, that is also acceptable and it is come in textbooks also now, it is not necessary to have a key Barrel always to make it a, you have a drill, you are used to the drill, you make one Barrel here, as you make the second Barrel just behind it in the temporal area, frontal temporal region, this bone cannot be cut with the B1 bit, this bone, you can come like this, come up to here, when you are coming like this, you are coming the base, this will always stuck here, take it out, you can just rotate it, take it out, use the AMA towards what are at the terminology, keep on changing depending on the bits available, you drill this part then you can break it, coming back to this sterional again, there are two structures to protect when to making a skin incision, one is superficial temporal artery and there is a facial nerve, so which are temporal you can palpate and be planning your skin incision accordingly because it can be variable and sometimes quite often you can cut the superficial artery, it is always better you do not cut the main stem, it divides into two, a frontal and a parietal, your possible will have to cut sacrifice one branch when you are taking incision, but always try to be careful about the fat, it should not coagulate the main superficial temporal artery, the second is how to protect the facial nerve, the frontal branch which crosses around the middle of the jigayoma and because if you you may do a grill conatomy sometimes patient have a little bit of grouping of this thing, this is not uncommon, this we have seen, so there are two ways to avoid injury to the facial nerve, one is you directly skin you take it down to the muscle, you take it down to the muscle and erase the muscle along with everything, you will not damage the facial nerve at all, so this is one example, but sometimes you want a little more exposure at this base and you want to take a separate flap, skin flap separate and a muscles flap separate, so how to do that as a classically described by Jassar Gail always follow that principle, the temporal muscle has a superficial temporal fascia and a deep temporal fascia, the deep is on the deep surface of temporal and superficial and superficial, the superficial temporal fascia in the anterior part of this frontal temporal and the anterior one fourth splits into two and encroaches a fat of fat, which is called the sickle shaped superficial fat of fat, so once you are reflecting thus you are in the signal lose a real tissue, lose a real tissue we always dissect, the posterior part you keep on the signal like that, when you come to anterior cut that superficial temporal fascia and turn into the facial fat of fat, if this is a temporal muscle the anterior one fourth of temporal muscle and then tear 25 percent of one fourth of temporal muscle, the superficial temporal fascia with flit and that, so in the entire part of the incision with your knife you enter into this superficial temporal fascia and see the fat of fat and go below it, because the superficial layer of the superficial temporal fascia will carry the facial fat, in this way you will avoid those things, so this was just what we are going to add on to the, this is standard teriyanocardomy, these few points will help, I have learnt this over years and years, it is better to know where forehand why spend time in cutting and doing damage before you learn, before coming to the teriyanocardomy again, the positioning everyone will be well in different place and many times you ask your assistant to position and you come when the teriyanocardomy is made, till now I will always like to be present when the position is made, I think I follow the principle I will advise you also to follow it, when the position is made, after that you can go out and come back again if you want, but when positioning is done you always will be there, one basic rule to follow when you are positioning patients supine, lateral, 3 quarter prone, prone is you draw one line from the extent of this you like this, okay, everyone knows this line from one extent order in meters to the, a legion is anti-aito it, you can do in supine position, then that basic rule, a legion which is anti-aito this line you can do in supine position, a legion which is basically posterior, you have to modify your position, which can be, if the legion which can be either prone or sitting or semi sitting or a lateral, so these things you have to choose depending on your legion, now whether you want to use a sitting or a prone or a lateral will be decided upon your preference and your experience, I have given up using 3 quarter prone or part position most of the patients, the position should be simple, because it is convenient to the patient to the anesthetist and to the surgeon, just give an example a CP angle tumor, so the position this cat for a CP angle tumor or 3, one is lateral or part one position, second is supine with the head turn to one side with the shoulder and third is a sitting, so there is no right and wrong again, I personally do in supine position, I think this was most comfortable position with one pillow under the ipsy lateral shoulder, turn head only little bit, when you turn in the head you almost look at the sternum asteroid also, of course it should not be too much flexed, if you flex it too much, you have a other anesthetist to check the airway pressure, do not turn it too much, if you turn it too much and the sternum asteroid becomes taut, that means you may be putting some pressure on the vein and most of you have good operating tables, you can turn the table, why turn the patient when you turn the table with some support on this side, so this is a little bit about positioning, about retro mustard approach in almost all CP angle tumors, unless it is a jugular foreman tumor extending into the C 1 C 2 area, you need not open the foreman magnum, it is not required, unnecessary bone word is not required, you need not remove the foreman magnum day, so what is required is when you are using a lazy ass, the lazy ass is starting above the pinna, this is the supermajus, just not above, just at that level of pinna, but one finger blade or two centimeter behind the mastoid base and when you are going in fairly, you turn it medially, why do you turn it medially, just to avoid engineering the vertebral artery one and you can have a better exposure of the foreman magnum area, but you need not expose the foreman magnum completely to do that, then third thing I wanted to add was, we have talked a lot and you must have seen so many skull base approaches, anterior patrocel, posterior patrocel, orbitosarcomatic, keyhole and everything, the skull base approaches have also evolved, at present, I think posterior patrocechomy should be relegated to a historical archive, most of the times, 99 percent of the times, you will not require to do posterior patrocechomy to remove any tumor, so posterior patrocechomy we have spent so many years learning how to do mobilization of the visceral nerve, how to do the semi-circular canals, but at present, I think most of the people who have done this also have left it, so you must be familiar with orbitosarcomatic, of course, has come to stay because it gives you very advantages, orbitosarcomatic, a standard retro sigmoid approach and some variation of far lateral, this is enough, you need not go spend hours doing a lot of skull base bony work, okay, so just few tips because this is my favorite approach, orbitosarcomatic approach, I am quite fond of this approach, so I will just tell you and I do it in a single piece, so I will just tell you how I do it, orbitosarcomatic is a good approach because it gives you a basal approach and it can be used for complex anterior circulation rhythms for, if you are operating once in a while upon posterior circulation rhythms and for the petroclival region, because it allows the assess to look up into the brain without having to retract the brain, so that is very important, without having to retract, you can look up, orbitosarcomatic can have very variations, I will just tell you a standard orbitosarcomatic, that involves exposure of the frontal region, the temporal region, orbit and the zygomatic region, so the bones which you have to remove is frontal, temporal, part of the orbital roof, okay, across the zygoma here and the root of the zygomatic process, I will just tell you in a single piece what bony cuts you have to make, then depending on that you can do your bony exposure, you have to make one cut here, the zygoma has two roots here, one is going here and one is going here and the lower part is that you do not have to go here and open the temperamental joint, so this has to be cut here, this can be cut with a bit or a saw, whatever it is your choice, what are you, or with a central saw, just a giggly saw or a cut, so this one cut has to be here, other cut has to be across the zygoma, if you are too close to this area, you will fracture it here, how to know where to cut is, always look for the zygomatic facial foramen, it is usually present in the center, this is the level where you should cut it, at the zygomatic of facial foramen, sometimes there are two foramans, sometimes there are one and most of the time there is a foramen available and once you see one foramen, the superior most is the, first one foramen is the one level where you should cut, so you should cut here and third is, when you are here at the superorbital notch, it is always possible as your Sanjay already told you, just do a little bit of drilling and take this nerve along with the periorbita, so what I do is, make one burrow here, one burrow here, one cut here, one cut here and stop, I do not, and come here, and this one little bit, I do not cut this thing here, because I want to remove it as a single piece, I do it as a single piece, it is just a variation, your choice what do you want to do, so from here to here and stop here, then you have to carry this cut into the orbit, okay, and you have cut here also, and the other cut is like this, so this is one cut, one cut here, cannot be like this, like this, and this you can use various ways of cutting this, always use a chisel and hammer, because that is the best way to avoid cutting the dura, if you use any power instruments, you can cut the dura here, okay, I am not going to detail of this thing, and then you can just break it like this, so this was about orbital diagrammatic, so since lots of when talked about, so many crinotomies and positioning, I will just show you one more thing, just you tell me now, how will you deal with this patient, this is nothing unusual about this, all of you see this, so if you mark this tumor on this skull, how will you do it, you see the first step before making crinotomies is to be exactly knowing where the tumor is on the skull, so what are the landmarks we will use to mark this tumor on the skull, the simple thing we will say every day, what landmark will you use, okay, one is you must know the coordinates which are, second landmark, Parathalaminase, okay, so one is you must know how far behind the cordon switcher the ligian is, Parathalaminase, you were approximately know where the ligian is in relation to the cordon switcher and Parathalaminase, this is one thing, second midline, you must know when you look at the cordonal images, how far from the cordonal images, so one is, sahital image will tell you cordon switcher, Parathalaminase where the ligian is, you can approximate RDA if how many centimeters behind or in front of the Parathalaminase, cordon switcher, second is how far from the midline, Next, what is the third dimension? The third thing is, you see, you have to know how high from the base or how far from the midline it is. So, how do you make out that, which cuts will help you marking it on the skull. You know from the cordonless switcher, you know the platylaminase. So, you must know above the orbital middle line, how much high it is. So, you look at the axial cuts, they are either usually they are 5 mm or 10 mm. You see the first cut, orbital middle cut, it at how many centimeters above the orbital middle cut, the legion is started appearing. So, that you can do, this is the orbital cantho-meter line. Suppose, it comes in the sixth cut and each cut is 1 centimeter. So, from this cut, it is starting 6 centimeters above and ending about maybe 9 centimeters. This is a basic rule. I mean all of us follow this, but we must know how to teach it to your students also. So, these are the cordonless switcher, platylaminase and how high above the orbital middle cut the legion is starting. So, this will help you making the legion on the skull before you mark it, cannot make. Okay. So, what do you mean or what approach will you use for this, the orbital diagrammatic. Okay. And what else, orbital diagrammatic with what, additional anything, ACP drilling, because you want to decompress the optic nerve, the optic nerve is not involved, it is pushed to one side. So, if you, patient may have come to you only with vision loss and you do a tumor removal and vision doesn't improve, what is the fun. So, that is why the drilling is important of the ACP. In this patient, orbital diagrammatic with drilling of the optic nerve, so that you decompress and remove that. Now, this, what issues will you have while planning the approach? For additional information, we would join and how will you plan your approach for this patient? There is a vessel inside the tumor. So, your concern should be this vessel. So, you may do an angiogram also to know whether and you have to know that whether the cavernous sign is IC is also involved or not, but cannot be able to use for this. Or you want to do endoscopic, different experience people may be using different approaches. For example, if I have to do it, I will use a standard terional with a little skull base work with a swenard ridge drilling, every extension of the orbital foreman, I will remove that also. And you have to be aware that it is not necessary, that if there is a legion in the cavernous sign is just leave that, not necessary to do a total exigen. Sometimes it is better to be safe and you have to do extra duraly, this is a meningioma. So, most of the supply will be from the extra duraly. You de-bascularize that dura before you open it, okay. You can de-bascularize the dural opening can be little just on the tumor, keep on removing the tumor till to get outside. So, terional cannot be with swenard ridge drilling and possibly ACP drilling if required depending on the extension of the foreman. De-bascularize the dura, open the dura and keep on de-bulking the tumor till you become, de-bulking the tumor is very important. Till it becomes smaller and smaller and smaller, then you have to see around the reckoning approach. I mean we will not discuss what this is about approach. You have seen so many approaches. So, you can come through the top, endoscopic and through the foreman you can enter into this curve, okay. Again, what is the problem in this? Simple, why am I showing you this? It is simple thing, anyone who has done his neurosurgery anywhere with the two years of experience can do this thing. What problem can you have? If this looks like a same, but nothing to worry about everything. But still sometimes you can have problem with these delusions. Why? What surgical problems can you create which can cause postoperative morbidity? This is a meningioma, but normally we do not have, I mean you can have of course meningioma, there is edema around it, which is a little unusual. So, this edema can be usually because of what? Yeah, venous compression or pile breach or sometimes we wear secretory meningioma. So, the problems you can have is and sometimes in this region, you almost always have one vein on the anterior spec, one on the posterior spec, anyone. So, in this what has happened, one of the vein has been correlated. So, you have a post-op in edema. So, this increases the morbidity in the post-op period. So, as like any other tumor remain, the principle is do not coagulate any vein and in meningioma especially do not cross the arachnoid. You keep on debulking at the end of the tumor, you should not be seeing normal brain, you should be seeing only arachnoid. At the base, you should be seeing arachnoid all around, you understand what I am saying? So, this is what, what cannot be will you use, DACA aneurysm. You see, this is a routine DACA aneurysm and many people, I mean, of course, sometimes the people get lost while trying to find where the aneurysm is. You keep on searching whether you are proximal distal and you keep on dissecting and no aneurysm seen. What are the cannot means available? Again, I am saying no right or wrong. What are the available cannot means for this? What principles will you follow? What happens is, sometimes if you are not careful, you make a cannot mean which is to posterior to above the base. This is a skull base. See, somewhere here is a crystalline. So, this aneurysm, DACA aneurysm, standard DACA aneurysm which are at the genu or almost always within 1 to 2 centimetres of a skull base, okay. So, your cannot mean has to be a little basal, whether you use a unilateral or bilateral is a personal of choice. Some people do a bilateral, basic frontal and then cut the crystalline, a durab of the crystalline. Some people use a unilateral parasitical approach, but you are too far behind. You will always be hitting somewhere here, then keep on searching here and you come along the base. Release the CSF first, so that you have a control. So, this what I want to say DACA aneurysms are not very distal, they are distal, but they are close to the skull base, almost always within 2 centimetres of a skull base. So, depending on that you have to plan your cannot mean. Either you use unilateral or a bilateral is again depending on what is your preference. It has to be just above the supra-orbital margin and then you go. This is just switching tracks approach. This patient has come to neurosurgeon because of para-pareces. So, that means obviously there is a spinal extension, para-pareces and posterior column signs approach. This was a hydrated, I mean we have now post-op histology also pre-operative we consider hydrated as a possibility. So, the aim in hydrated is to remove it without spilling it, otherwise you have a lot of chaos. So, in what we did I mean you can we did a therocotomy and this was removed and total. But during and total removal it looked that it may rupture. So, what the cardiac CT was just put a needle inside and without trying to spill, the he fall felt that it is going to give rupture inside the classic cavity. So, you can do a controlled without allowing spillage that we done. And the same sitting then we turn the patient prone and did a hemiline. So, it was extra I mean let me on that side. Okay, just switching tracks again. So, this is a MC impact. What will you do for this? I am already showing you what we have done, decompressive. What precautions while doing a decompressive? Many a time all of us have seen you have a small, you see why just large what is called a trauma flap, all of you are not familiar, it is very important it may look, but some city is justified trauma flap for these type of, otherwise you have a chaos, large trauma flap. This is smaller than what I would prefer for this type of thing. So, just one last few. What will you do? We have done both, frame based and frameless also, but for this situation for navigation guided biopsies also is because you have to go transferable. If it was in involving the mid brain, you could have come from above or thalamus, but in this you will have to transgress, if you go from frontal standard, you have to come through the thalamus or the mid brain, so that is not justified. So, when you doing this steutatic biopsies through the Pustey force, then navigation is helpful. Again, I think last one or two approach, this patient has been advised by consider that Sajid is required to prove the diagnosis, so what approach will you use? What I thought was that this tumor is surfacing here. So, this is simple, follow this vallicula and this turned out to be a sort of peanut or something and it was soft circuable tumor, it was extra axial, most of it came out. So, the approach, it looks like that you have to go like this, but if you are going like this, you will be transgressing all the nerves and going at T to the nerves and the aim is always do no harm. So, surgical planning is, it is surfacing here and once you into the tumor, you can go just keep on entering into the tumor. This is a least minimally damaging approach. Again, this was just showing what I told you before also, importance of veins, not difficult to remove this tumor, but you may have to plan your kinatomy depending on the venous nerve, MR venogram sometimes is helpful depending on the nerve. So, it preserves, almost always in this location, you have one vein and here, one vein for here, sometimes it between all. A basal bifrinter kinatomy, you may or initially I used to you include this orbital rims along with the kinatomy, but not as I stopped doing it and the important thing is, in this what we were saying that day, this, all attachment is here, so before you open the door, D-bascular is it, D-bascular, D-bascular and in this, you can remove this whole tumor without having to see or touch the brain, just remain in the tumor. This is very important, you can remove this tumor by any means, but you removing this tumor without having to touch or retract the brain is most important thing. This is again, orbital diagrammatic or something like that. Approach, there are three approaches available for this. One is, you do a postiparitosectomy, pre-sigma approach like this. The other is, you do FTOZ, you do or you do a sub temporal. Third is, you can go a retro-sigma approach and like this. In this patient, I use a retro-sigma approach, the nerves are spread on both the sides and you can work between them and it was totally seen by simple retro-sigma approach. Why I showed this is a retro-sigma approach is one which is very good for some of these patients sometimes, you can avoid lot of bony work and you can extend the retro-sigma approach if required by doing a tentative incision or from behind if required a little bit of retro-sigma anti-retro-sigma. So, do not give up on retro-sigma, this is an excellent approach and it can take care of so many legions without doing a extended skull base work. Approach, I would do a propane event without seeing a venogram. Whatever veins are there displaced, whatever veins are there, they are displaced. This tumor is no way inclusive. This is a meningioma. This is displacing all the veins. So, whatever approach you go, you first see the tumor. So, I went for this for a propane approach because it can give you exposure by cutting the tent from below and if required of the opposite side. Again, last approach, what I am saying is I am again emphasizing retro-sigma approach is a good approach. Total removal by retro-sigma approach. You see, this is called a lateral supra cerebellar approach, you know, did you have to recover and how do you tackle this tumor? This cannot be seen by any angle from the retro-sigma approach. So, how do you tackle this? Always remember that the anterior incision you give from this side can also be done from inferior also. You just cut the tent, you see the under surface of the temporal lobe and the middle part of the temporal lobe. So, again emphasizing maybe it is an old thing, retro-sigma approach is a good approach. Can be used without doing a pre-sigma approach in many of the cases. Same again, simple retro-sigma approach, no need to, they are totally seen by simple retro-sigma approach. That is all.