 This presents some straightforward causes, cases so we don't do, for example, call it cyst removal. We do it microscopic, endoscopic assisted for visualization, but in general we do it standard. The equipment is quite limited we use, so may fit fixation. We have an endoscope with one working channel and so with one working channel you are even limited with your possibilities to, on manipulation, we use a foggy, monopolar, in some cases a forceps or, for example, in difficult cases for penetration we use a pair of scissors. So this is a case similar to what we have seen starting a month ago with the supercell assist causing the head circumference to be too big and it's always very important that you, as it was visible with the presentation now that you really think about what you want to with your intervention because you have to choose your trajectory and you can't manipulate, it's impossible. You will harm the phonics, you will cause hemorrhage in the perenchyma. We always say to our residents don't do ventricle tourism, so it's dangerous, it's really dangerous, so choose what you want to do before and then do the job and otherwise you have to do a sediment intervention however. So this after puncturing the lateral ventricle right on you see the cyst. In this case we took a, not for perforation but for shrinking, we took a bipolar coagulation and then it just takes time. You have to shrink it stepwise, shrink, shrink. And now you, the forearm monroy, there's no major attachment so there's some kind of communication, left-right communication already. Now you have this nice view similar to what you have seen, the pituitary stalk, the client's posterior pulsation but apparently it's not completely free and only if you have really made a penetration so that the subordinate space is susceptible then there will be a clinical effect. Now it's quite floating and we let it like this. You can, could even enlarge it of course. There you can of course. In this case where you have a lot of space you can visualize it. So this was a lady with 33-olds which had typical signs of acute hydrocephalus which was visible in the CT scan. The family reported that there are some memory disturbances and we saw this mask, a thalamic mask and we decided to carry out a hydrocephalus treatment and a tumor babsy and what maybe perhaps were important that in general. So you may have risk of bleeding of course with the ETV but also with the tumor babsy but in general perform first the trigger systems to me because there's a less risk of hemorrhage which may blur your vision and after you've done that then go for tumor babsy. And you see it's not that chronic so it's not that transparent like you may see it in other cases and there the basilar artery is just behind it so it's a bit atypical, more lateral perforation we choose and it's a quite standard procedure that's very nice about it. You can't see it anywhere so this is a tumor not too superficial and if you have appropriate pieces stop before it starts to bleed and you will have some trouble. So it was a glioblastoma but it was one of the few patients she's now six years in follow-up just biopsy and she went well, no. She's lucky yes but the memory disturbance after radiation therapy so it's a problem but otherwise she's doing quite fine. Here you see the mask now it's follow-up, six years follow-up and you see that the tumor is literally not any more present and there you see this T2 artifact due to the CSF tumor and this arachnid cyst it's always a matter of debate if you do surgery or not patients go with headache to their GP or neurologist and they make a picture like that but this is one of these cases where there's some mass effect visible and we just made parietal excess perpendicular to the plant root and you can do it microsurgical but what is nice is that you don't empty the room and you don't have a collecting space and so it's quite good to work and you have less risk of a hematoma or stuff like that and it's always the same technique you do some shrinkage to get resistance and if you have some resistance you can perforate it easily and then you make the communication that's always the same principle because it's not a high flow if you have a high flow hydrocephalus or high pressure then the opening may be small but if it's low flow then it's better to make a bigger opening I think that's perhaps the rule which is mentionable so follow-up was fine like this and the last video just may appear that there's some bleeding when doing ETV and it's the simplest method to stop it just to stay in place make a bit of compression in it ask their anesthesiology if there's any change in blood pressure or heart rate and then it stops perfectly like this thank you