 So, we go on to the third ventricleostomy. We have talked about the endoscope going from below and now we talk about the endoscope going from above. There are two basic indications. Hydrocephalus and tumours. We will talk about hydrocephalus now and it is not that if you know ETVs or endoscopy can replace all hydrocephalus, no it is not. VP shunt is the age old treatment. It is the gold standard treatment but it is the necessary evil. Everyone has to know about the VP shunt and will always know how to do a VP shunt. VP can replace anything but we have to understand this very briefly but what are the drawbacks of shunts, etiology of hydrocephalus, what are the problems that are faced with ETVs that you must know that when to abandon, what are the indications and what are the contraindications and can the ETVs replace some of the shunts or all of the shunts. Well shunts all of us have problems staying in the institution for 22 years. We have a gallery, a complete art gallery. A shunt is going to opposite side, horns, many of you are smiling and many of you may have had the cause of it, intramasphoric fissures in the brain and still you can have haemorrhages, extra dural in the ventricle, subdural while taking out or putting them in. Whatever you do, haemorrhages can happen. They can have over drainage, they can have infections, they can have endocolitis, migration to different places. So when this ETV came in it was like we talk about now the endonasal endoscopy. The ventricle endoscopy when I learned it in 2000, it was like the endoscope would cure all the hydrocephalus. It was never to be well-accepted indications, aqueductal stenosis, arachnid cysts, tectil plate tumors. Posterior fossa tumors are not an indication of third ventricle ostomy. Because the brainstem is pushed in front, intraventricular neurocystisircoses and dandy walker syndromes. There are some relative indications in which you have to guard that you may have to go in with a shunt. One is an aqueductal stenosis with a very small child less than 2 years of age. That's a relative indication. But other relative indications are past shunt infections, post meningitic hydrocephalus and post haemorrhagic hydrocephalus. A very important to note that do not do a third ventricle ostomy on a CT scan. You must have an MRI scan. You must have a T2 MRI scan in which you must see an aqueductal stenosis and you must see the third ventricle bulging down. An MRI would also help you to see the form in a monorail and plan your trajectory. Third ventricle ostomy should always be done under general anesthesia. There are some people who claim to do it under local anesthesia. Please do not do them because it can be very dangerous putting an endoscope with the patient bucking. Scopes can be hitting the forenecks everywhere. And the patient is supine on a headring on a horseshoe and the incision has to be planned. The incision is not the usual cocker point in front of the coronal suture. It's not that. You must see the T2 weighted MRI and it is usually the interpretant of the ocular cistern, the form in monorail, the line joining, the front to projection. A normal third ventricle ostomy is nearly about 2 to 3 centimeters in front of the coronal suture. Planning an aqueduct to a plastic or a tectal tumor biopsy is somewhere about 5 centimeters in front. So if you're planning both, you want to look at the aqueduct along with that you want to third ventricle ostomy, make a barrel in the middle somewhere around about 4 centimeters in front. So the technique is that you go in the lateral ventricle across the form in monorail. Why this trajectory is important? Because you cannot have a lot of movement in this area. You cannot have play unless it is a congenital hydrocephalus less than 2 years of age in which we have widened from a monorail and there's no septum polycytum. But in others, you cannot play around here. So you have to be there where your end trajectory is. You cannot be mobilizing too much. Go to the third ventricle. See the mammary bodies. Look at the premammary membrane. Always look at the dorsum cellae. In front of dorsum cellae would be the pituitary infundipulum. Behind it, puncture there. Do not puncture close to the mammary bodies because that will be the basilar artery. Always puncture. You can puncture with the Fogarty 3 French, then dilate with 4 French, 5 French. You can use a bipolar with no current. With more experience, you can use a fine scissors over the dorsum cellae. You can dilate the stroma with Fogarty's or you can even dilate with the ventricle ostomy probe. Very important in kids that you must plan your incision. Do not use straight incisions. Use a semi-circle or a curved incision. Let the barhole be in the center of that so that there is always some covering over that. Have another layer, one layer of pericranium that you can suture on top. When you incise the dura, do not incise the cruciate manner in a third ventricle ostomy. Take a V-flap or something which you can replace. Always plug the cortical wound with a gel foam and a good enough long gel foam that can come out so that it does not go into the ventricle, especially in this small kid. This is to prevent a post-operative CSF leak. This is a simple third ventricle ostomy with a tectal-plated lamina or a kid with a tectal-plated lamina. Look at the mammary bodies, look at the dorsum cellae, make a puncture there. That is, look for a second membrane. That is the first membrane. That is the mammary, pre-mammary membrane. That is the brain tissue. The inside is the second membrane is arachnoid. That is the membrane of lilyquist. Dilate with cereal for Fogarty catheters. When you are dilating, don't dilate it with your Fogarty being there because this interface is between the clivus and the brainstem. That does not move. It does not move with your balloon. Whenever you are dilating, you come out. The balloon should keep on coming out so that you do not avulse the perforators on anything. Say dilation should be in this area, not between the brainstem and the clivus. When you see the second membrane, you see the bacillor artery. That's a good third ventricle ostomy. Your scope around about an 8-millimeter scope should actually pass through and you can see that. When we talk about a more difficult third ventricle ostomy, the younger the child, the more transparent membrane would be. The more congenital abnormality, the more transparent membrane would be. The more the transparent, it is not simpler. The more transparent can be actually more difficult. This is the transparent, but it was more of this is the dorsum cellae. That's a pituitary wind balloon. This is an old video. We tried with three French, four French, five French. It looked that we can easily perforate it, but it doesn't get perforated. It is transparent, but it's pretty thick. Try the bipolar there, still nothing happens, because this is actually dipping down as well. This area which you are seeing is actually somewhere over the upper and the middle ives. You put some hard instruments, they are going towards the bacillor artery. With practice, you can give the safest thing which we found is to give a small incision over the dorsum cellae. The moment you give a small incision over this prememory membrane, it just slips back. There is already so much of this flow that it just slips back and you can see the second membrane. You can also give another small incision and that is the third ventricleostomy that automatically gets created and you can see then you can see the normal thing happening. Again dilation with the Fogarty with the balloon coming out. Do not dilate while you are right inside playing with perforators. Incision of the second membrane and inspection of the perforators beyond that is very important. You must be sure that you are successful. Aqueductoplasty is something that you stopped. Initially we were doing it, 10 years ago we thought that we should make two openings instead of one. We used to make a third ventricleostomy. Then we used to go back, look at the second membrane then go back into the aqueduct. See the aqueduct stenosis, do an aqueductoplasty. We did some, earlier we used to be more enthusiastic, put some shunt tubes there, think that our CSF flow will work but the shunt tubes used to be found somewhere in the later CT scans in the Furman magnum or somewhere one actually slipped down in the lumbar spine as well. So then and we were more, I was so like you know a tool then we used to put parts of flexible endoscope through the aqueduct and look at the fourth ventricle how it looks like but that these are things that should not be done. These were things that you actually do when you are learning things new. How do you assess the ETV outcome assessment? You must see the technical pulsatile flow. The clinical is very important for a child, regular head circumvent measurement. A CT scan may be after a, if the child is well maybe you may not need a CT scan but child is unwell get a CT scan, rule out a hematoma or a subdural formation. An MRI after three months and then after one year and one yearly till five years is usually advised in literature but I usually get it, don't get it done after one year. To see the CSF flow and also to see whether there is a sine CSF across. This is very important. Don't be disheartened if you have done an endoscopy. The fontanel is level. The child is not crying in healthy but the head circumference is not coming down because after a third ventricular ostomy in a child there is but these are small, small things that you must note. Even a 10% reduction of a ventricular size, a disappearance of a peri-ventricular ooze, presence of a T2 flow across the ostomy and straightening of the flow of the third ventricle. Resolution of the suprapinial races is the size of the MRI, if that disappears that is sure that your child is fine. But if there is a 10 pseudomoningo seal at your semi-circular initiation, if there is even one drop of CSF leak that means your ostomy is not working and prominence of sulci. So this is a pre-op and even this is a post-op and you have the peri-ventricular allocency finishes and your sulcai, gyri, better seen than previously. This is enough. But even a drop of CSF leak means do not keep on resuiting and get put a shunt. That's better. This is something that is, this was an aqueduct to Plasti plus the third ventricular ostomy. So you have a T2 flow and along with that is a sine through the, what about ETV failure? If you follow up your ETV kid till 5 years, usually after 5 years it never fails. The most important failure is within 4 weeks because non-absorption in which you have to put a shunt, delayed is after what you have created or it blocks. Then a redo ETV may be helpful. Predictors, most important predictors are the previous meningitis, myelomoningo seal, shunt malfunctions, repeated shunt infections, carry malformation. In all these, usually if you have all these, the success rate would come down below 30-40%. These are the complications, totally preventable are second membrane perforation and you should not be damaging the basilar artery and the hypothalamus. Do not use current over the thalamus and the hypothalamus. Partly preventable, that is something that is sometimes not in your control, a difficult perforation, stoma closure or gliosis, CSF leak meningitis. Not completely at all preventable as you cannot fight against the nature. If there is a CSF absorption defects, specially on kids less than 2 years of age. Plan this is usually we follow. We do an ETV after strict indication and patient selection. Do not do in kids which have a mantle less than 1 to 2 millimeters in size. Do not do with having no mantle. Follow the patient. The patient is well, just follow up. Follow for 5 years. If the patient is unwell, you suspect an ETV failure. If the CSF flow on an MRI, if you have a CSF flow, you do a UP shunt, do not wait. If you do not have a CSF flow, you actually do put an endoscope again. The stoma is open. Put in a VP shunt for the same opening or the same is closed to a redo ETV. Literature says that ETV and shunts, there is no statistical difference and the overall success rate of ETVs is right from 22% to more than 90%. The overall rate is around 60%. In literature, if you have myelomeningoceleinfection, the success rate is between 20% to 40%. And in children is around about 50%, less than 2 years. Above it becomes around about 70, 80% in some series more than 90%. So it is, a shunt is a necessary evil and endoscopy cannot finish all shunts. It is something that you have to know. But if you select your patients well, ETV has a very high success rate and very low complication. But for that, you have to planning your cases on MRIs, have a strict selection. Thank you.