 Okay, I think roughly goes through to the topic Dura repair which is very important. Of course we have to differentiate in between Dura repair in trauma and in our surgical cases where we create Dura leakage and then we have to repair it. So basically you must be aware that most of the leakages that we're dealing with are at the frontal basal area, lateral basal is very rare that you have to do surgery on, combinations are even more rare. The roof of the ethmoid is mainly affected and the olfactory fossa as well as the frontal sinus. The sphenous sinus basically is well protected and especially in the trauma cases it's less than 10% where you get the leakage from there. So this is basics to the where can be CSF leakages come from. Then what is the algorithm, the diagnostic algorithm that we are using? First of all of course the patient's history that is important and then you have to do a couple of investigations. We do special thin slice CT scans, MR imaging with special CSF sequences, a diagnostic evaluation of the nasal cavities with an endoscope by an ENT may be helpful and that what we have now used routinely is not the better to transfer in but the better trace protein test. Better trace protein is very sensitive. You can really differentiate especially when we do this endo nasal surgery we can really differentiate in between secretion from the mucosa and pure CSF. If it is positive and the leakage will not stop by itself we do a surgical repair. During the surgery it can be helpful to administer fluorescein and this is another tool that you can use intraoperatively. So first of all to come to the CT scan, CT scan may show you the irregular side at the here especially at the frontal roof that you can see where there is a bony defect. Therefore the CT scan is good whereas with the MRI with special sequences you can often really see where the CSF runs through which is the ethmoid plate right here so that you can localize the lesions. So once you know where the lesion is you can then think of what is the best approach to go there. So these are the approaches to the frontal basal skull base. Endo nasally there's the paraceptal approach to the olfactory fossa and to your third of the olfactory fossa. This is pretty easy. You've seen it yesterday. Once you go in we have not done the approach to the cribiform plate but it's just midline approach you go to the cribiform plate you're just there you see the leakage immediately then you have the paraceptal approach with a sphenodotomy. If you want to go to the posterior sphenoid wall to the cellar floor to the sphenoid roof transethmoid is needed if you have to go to the middle and posterior third of the olfactory fossa and to the ethmoid and very difficult of course is that if you have a lesion at the lateral wall of the sphenoid sinus then you have to combine the transethmoid with a pterygoid and sphenoid approach to come far lateral and to close that defect. Basically let's come to the grafts that can be used you know for closure. You can use autologous nasal grafts autologous extra nasal and of course heterologous grafts. So first of all what are the autologous nasal grafts you can use the middle turbinate seen it yesterday with you cut the middle turbinate you can use the middle turbinate for closure. The septal mucopericondrium you can create this vascularized mucosal nasal septal flap or even other flaps like from the inferior turbinate or the palatal flap for closure. Autologous extra nasal graft, abdominal fat, fascia or temporal fascia and then of course there are a variety of dural substitutes available that you may use in special instances. We use fascia tutoplastis fascia human fascia that is the heterologous graft that we are using in my department. So besides the grafts of course you have to think of what is the technique of the dural reconstruction. You can use a single free graft for example single free graft is good at the olfactory groove. If you just have a lesion there a tiny lesion then a single graft may be sufficient just as an overlay and you give some glue and fix it right there. Multilayer free graft is important for for example large surgical defects once you have made that. As I told you for a plant of fennel dalamene in germo, cranium, foreign germ or whatever you need multilayer free grafting and then in combination with the vascularized pedicle flap. Just to show you the skull base if you have a lesion at the cellar that kind of defect then you can use a kind of what we call the occlusive technique because you can put in some graft right here and use it as occlusion because this will keep in place because of the special anatomy of the cellar. So for example if you have a leakage from the diaphragm as it is shown here we usually just take a little bit of fat keep it there with glue and that's it. The fascia is doing at least as well but as I showed you from the cosmetic point of view we like to just to make a small umbilical incision per umbilical incision take a piece of graft put it in there keep it there with glue and that's it. But if you have a leakage for example here in this flat area at the planum sphenoidala or planum esmoidala then fat or whatever you would take as occlusive will not fit because if you want to push it in by the pressure of the CSF it will pop away and you will have a leakage again. So this technique will not fit for this kind of anatomical side and therefore you need a multi-layer technique that's what we started with first multi-layer means that you have an underlay which is intradural and the other one is extradural or even extra-osseous so that you have at least two different layers that keeps the CSF from running out but we have realized the larger the defect the less this is sufficient if you do not use a flap as well and so in the larger the defect is then we use this nasal septal flap you've seen it yesterday so the basics for the flap is that the pedicle comes from the sphenopelaton artery which is the posterior nasal artery and the pedicle is limited by an at the superior apex of the koana and then another incision at the side of the sphenotosteum and the pedicle is in between and then you have to create a broad flap a broad flap that can cover you know your defect but you must be aware not to destroy the orfaction as you have seen it yesterday that means the first 1.5 cm here should be spared this is the superior apex of the koana actually now we are running from here get a good pedicle and then you go parallel to the infirterbinate that is the infirterbinate go all along here even up to the nasal orifice really high up here make the incision right up here and then stop there just make an incision the curvilinear incision right here and then you go back at this point you stop you see the ostium side this is the superior turbinate and then you make your second incision along the ostium and then this is the more difficult part you must now go along parallel to the superior turbinate but now not too close to the skull base because here is the orfaction but on the other hand you must make a broad flap people do often the mistake right there you come back too early and then you have a kind of banana flap you see it must be a broad flap otherwise you have a very narrow flap that will not fit so you must really once you have seen the turbinate go up all the way and create a broad flap and then you push the mucosa from the cartilage and from the bony septum and at the end you have the nice pedicle right here and you can push then the whole flap into the nasal pharynx and then you do it in the myxillary sinus if you have to do some clival work it may be cumbersome that your pedicle is in your way you must be careful doing the surgery by drilling not to come to your flap and destroy your flap so in clival cases we sometimes push it in the myxillary sinus it's out of the way otherwise in the nasal pharynx and keep it down there at the beginning it may be good to mark it for example with the mucosa so that you bring in the correct side on your bone because if you put in the mucosa side on the bone then you will have some mucosil and infection on that so that you not mix up the correct side you can just mark it this is in a patient the flap has already been created this is just the last pieces that we make the incision and pushed it then back and at that time we used something I just want to show you this is the flap now you see it's not that easy to work with the flap push it into the nasal pharynx at that time we used a duress substitute it was called neuro patch here I will never use it again because the interesting thing is that what we learned the lessons that we learned you should use whatever graft something that is smooth and that you can nicely fit to the defect like this neuro patch here is difficult to bring in and often you have edges where the CSF may leak and then we put in the flap you see here but that flap was not correct in place you must take your time for the flap that the flap really overlays the whole defect and as it was here and then we put in some surgical seal or gel foam to keep it in place but I just want to show you this this was a clavocodoma I will show you the next video because this patient started leaking again but at the end we think everything is fine was well in place we were happy with it but the patient started leaking some 4 or 5 days after surgery at that time actually we did not use the balloon catheters that we are using now to keep it in place there are different solutions for that but I just want to show you how it looks like I think the surgery we have done then was a week after and this is the flap we put in the first surgery we put in some glue and I think some gel foam or surgery seal on that and left it in place like this and this is now the video this is just a week after look here how nicely this flap in a weeks time has been fit here but you see it moved from the lateral side here this is the dural substitute the neuro patch and you see there is some leaking there so if you have in extended skull based surgery this is a lesson we learned if you have a leakage again in a patient where we put in a flap we immediately go in again we never would try to use something lumbard drain whatever because they will go on leaking go in again identify the lesion here it was easy you see this arachnid has been built this was all gone in a weeks time and now we just put some fascia we have identified the area where it still was leaking we just left the whole flap on the other side and just push that part of fascia underneath this dural substitute and closed it that way and then brought the flap back in position and that was sufficient to close that leakage I have realized if you have a leakage in extended skull based surgery when you use multi-layer grafting and an asus septal flap you know spot where it is and then you don't have to remove everything you can just work on that tiny little spot but of course best is that you have a broad flap that really covers everything but I just want to show you the flap will shrink pretty quickly on and it may move a little bit and this may be a reason for leakage again what we doing after the surgery day after we do an MRI with the contrast medium just to see if the flap fits if you get an image that it fits and then some principles for the grafting very important this side that we have to put the graft on must be prepared by removing the mucosa never leave any mucosa on the bony side where you have to put the graft on you get an infection you get a mucosil definitely in pituitary surgery I did not say it yesterday in a normal pituitary adenoma not creating any leakage I leave the mucosa when it is possible because then you still have the ciliary function and it keeps the pneumatization of the sphenate sinus if there is a chronic infectious thickened mucosa take the mucosa off if I have extended scalpel surgery take the mucosa off you have to take the mucosa if you need a graft then very important the bone surface irregularities need to be smooth by drill you have to have a flat surface of the bone where you can really put the flap on the layers have to be prepared meticulously you have to avoid folds that was one of the mistakes of this neuro patch you have seen if you have something with folds that's not good you have to avoid folds and no synthetic material should be between the layers and one has to consider the shrinkage of the graft doing scarring that means the graft must be well larger than the defect size so if you think of that you can do a proper closure but if you do extended scalpel surgery that is my opinion or my feeling this is often surgeries lasting 4, 5, 6 hours so we have done the same that the Americans do we have built two teams so I stopped to do the flaps bringing in again because to be honest after these kind of surgeries you are a little bit not a little bit you are just exhausted and then at the end you are just fed up you want to finish the surgery and if you don't do that meticulously then the flap is not well in place and the patients start leaving and this is just really bad for the patient for everybody go in again look for that so we have now teams you know for preparing the flap this team will bring back the flap at the end and the surgeon who is doing the main pathology the tumor is different so we split our work and I think it is worth doing so what is the decision making if you have a minor leakage minor leakage I mean for example pituitary adenoma leaking from the diaphragm things like this where we use the occlusive technique interoperatively we put in a layer or obliterative technique that is what I told you and then a patient starts leaking again this is the only situation where I put in a lumbar drain and most of the patients that stops if I put some fat in the cellar and the patient leaks put in a lumbar drain for three or four days that's okay the smaller the leakage is the more you can use a lumbar drain that does not do any harm but I personally I know that others have different opinions to that but if you have extended scalpel surgery a large defect I am absolutely reluctant to use lumbar drain I have seen patients getting comatose with that really really it's really dangerous because you have a huge leakage the patient leaked a lot during the surgery and if you then are not carefully looking for the lumbar drain and you know about it you know how deep the lumbar drain what's the amount of CSF that is going on I have seen patients getting comatose if you're not keep an eye on that lumbar drain I'm very reluctant I don't do that so we do multi-layer and the flap if the patient starts leaking again I go in again I do a redo surgery and then if I just have realized it's a small like you've seen it before just a small leakage because the graph did not fit perfectly we do the redo and then you may put in a lumbar drain in that second step as well that is safe nothing will happen by that factors of influence of course you have to see what you've done if you've done a subarachnoid dissection so exposure that is a high flow if you've been in the third ventricle must have a very very good closure the size of the dural defect of course is important the location is important and of course the anatomy of the patient so thinking of all that you must have a plan beforehand how you want to reconstruct a dural defect and this is something very important because especially for the extended scalve surgeries everybody who is starting with that will have some mistakes and problems and I remember a child with a cranial for angioma I had to do four surgeries and finally I ended up to do a transcranial reconstruction of the defect because I was not able to do it endonaisily and it is mainly the lesions very difficult which are close to the carotid and the optic because there it is difficult really to get a flap fitted you know this is an area that may be very very difficult yes we have come back now to use what we call the reverse flap if we do the nasocephal we try to do the reverse flap if you nasocephal flap on one side before you take the posterior septum you raise a flap on the other side as well not the complete flap but the side at least where you take the posterior septum so the mucosa on the other side is still there and you just have resected the bony posterior septum and in that defect then you can flex you know you can bring around the mucosa from the other side so that at least parts of the blank septum ipsilaterally where you have moved the flap is covered and that is very nice yeah that helps healing that helps healing I mean the American group has shown that even if you don't do that after I think four or six weeks you have a re-epithelialization on the blank septum but it's much better if you've got that kind of reverse flap yes that's why we do it okay thank you