 So, the issue of the talk is the management of CSF leaks, and of course the management of CSF leaks is not as excited as doing great scalby surgery, but it's a very important issue because looking at the background, the CSF leakage is a serious and potentially fatal condition for your patients. About 10 to 25% of patients who have a CSF leakage are developing meningitis, and 10% of these die as a result of the meningitis, so it's really a fatal condition for the patient and you have to do something. What is reported in the literature, there is no evidence in the treatment of those CSF leakage. Classification in CSF-Rhinuria, the most reason for CSF-Rhinuria is a traumatic accidental in almost 80% and post-surgical, that means related to our treatment in about 16%, and there are some non-traumatic reasons which may be congenital or spontaneous, and some with a normal ICP and some with an elevated ACP, and if you have these elevated hypertension, you have to treat the hypertension as well, not only the leakage. Localization of the CSF leakage, of course, they are more often located in the frontal base because due to the nasal cavities, the paranasal sinus is more obvious to suffer a CSF leak than in these lateral basal fractures, for example. Most of the post-traumatic CSF leak after a scalp fracture is up to 50%, and of these patients having a CSF leakage, the risk of developing a meningitis within the first two weeks is 1.3% per day, that means after two weeks almost 20% will develop a meningitis, and in the first month it's 7.4% per week, that means almost 30% of those patients in the first month after a trauma can develop a meningitis, and if they have a CSF leakage, it may be subclinical, they almost all develop a meningitis in the following years. So what is our diagnostic algorithm to rule out or to find the CSF leakage? The first thing is if we have a clinical or an amnestic suspicion of a CSF ring we will ask if it's possible to collect this strain fluid, and then we send it to lab chemistry. I don't know if this beta-trace protein is known here, yes, so this is almost the same specificity and sensitivity as the beta-trace transferine, but it's easier to, it's not that time consuming, it's cheaper to have the results, and so this is our first choice in chemistry, and you see these are the levels in the serum, in the nasal secretion and the CSF, and you see how high it's up to 30% then 30 times higher than in the serum or the nasal secretion, and if you cannot collect fluid you can put a sponge in the nasal cavity for 8 to 12 hours, and you can send the sponge to the laboratory and they can look for a beta-trace protein. So if it's positive we have to look where we can find this CSF leakage. If it's not positive or we are not able to collect strain, this cystanochrome with a radionucleotide is an option, but as well you can do for diagnostic or also for treatment reasons, you can do these intratracal fluorescein and have an observation of the nasal cavity with an endoscope, and I show you a video, this was after a trauma, and the patient had a CSF rinsing, and these are the admirates, opened and you see this greenish fluid, there's no filter, this is only a normal endoscopic image without something special after a lumbotrainage and injection of these fluorescein, and you see these greenish fluid coming out, and so you have the diagnosis of a CSF leakage, you have the location of the CSF leakage, and after the reconstruction you have also a treatment control if there is no fluid coming out. So the imaging, it is reported that you have to use a high-resolution CT scan in a multi-planar reconstruction, and it's also, cystanochraphy is an option, but since these CT scans, the quality is so good now, meanwhile we haven't done a cystanochraphy for more than 10 years, so with a high-resolution CT, you almost can find the bony defects, and the same with the MRI, because of this really high quality of the MRI images, the cystanochraphy of the MRI, which is an option, is not always necessary, and again this is an off-label use, so it's reported to use it, it's reported that it is safe, but it's an off-label use, and only I want to show those, this is a frontal encephalocele, this and these are both so-called lateral sphenoidal encephalocele, or meningo encephalocele, which is a rare entity, and I will show you a video later on this patient, only to show the cystanochraphy with this radionucleotide, and this is indium, and this was a patient we had to operate four times on a persistent CSF leakage, and only to rule out after the fourth operation that it's really now solved the problem, the patient had an extra ventricular drainage, and via this drainage, we injected this radionucleotide, and we could rule out the persistent CSF leakage, so how to treat the CSF leakage, you have some non-surgical options, and you have some surgical options, and again there is no evidence in this, but what you have to know that in almost all patients within the first week, you have a spontaneous closure, yes, so you have on one hand the increasing risk of meningitis, and on the other hand you have a spontaneous closure, and you have to define where is the point, I have to switch from my non-surgical to the surgical treatment, and in the actual literature it's given that it's about 72 hours till one week, and it's exactly what was recommended by Denny in 1944, and then if you intend to go for a surgical treatment, you have to decide whether you go via a transcranial or a transnasal approach, and the transcranial approach was first described by Denny as well, the actual success rate were right, but the recurrence rate in this transcranial approach are as high as 27%, the advantages of this approach is that you have a direct access to the defect, and that you can also repair or reconstruct the defect at multiple sites, yes, but on the other hand you have a morbidity due to the transcranial approach with a potential hematoma, seizures, and osmia, the endoscopic approach was first described by vegan, you have a success rate up to 90% in primary surgery, and it's remarkably well tolerated and the complication rates are low. So what is our decision making for the transcranial approach? If the posterior wall of the frontal sinus is fractured, it's very difficult to reach with the endoscope, it's not good to control, so in this case we are going for extra-dural repair, if you have a major damage of the frontal base we go for extra-transcranial, if you have an extensive destruction of the nasal cavity it's difficult to go with the endoscopes, so we go transcranial, and if you have an indication for decompression like subdural or intracerebral hematoma, we choose the transcranial approach, and the transnasal approach, if we find in the CT scan a very defined localized leak, we consider the transnasal approach. If it is at the colibus or the sphenoid sinus, which is difficult to reach via the transcranial approach, we go for the transcranial approach, there is always the discussion whether it's easier to preserve olfactory function going transcranial or transnasal, this remains an open question, and if you have an intracranial hypertension, a brain edema or something like that, without the indication for decompression, then we also go via the transnasal route. Use of antibiotics, so given the current data, I think this is the most important statement, it's not possible to recommend the use of prophylactic antibiotics, so we do not give prophylactic antibiotics. For me there was some crucial point to deal with a CSF leak, the first is the flow, the higher the flow is, the more difficult is to handle the reconstruction or the defect, so if the sub-artnual space is opened, you have a rinsing, it must be open to have a CSF leak, if you have a large resection cavity after tumor reconstruction you have something like a cyst, it's difficult to handle and even it's more likely to have a persistent CSF leakage if you have a communication with the ventricle. On the other hand the next point is pressure, as I said if you have a hydrocephalus, you have hypertension, you have to treat this hypertension as well. On the other hand with a lumbotrainage you can decrease the intracerebral hypertension and for this, this is the reason why you have to consider a lumbotrainage. On the other hand you can use the pressure to create your wealth, I'll show you in the next image and the other thing is gravity because all your covering materials you put in a nasal cavity, they have the intention to fall down, so you have to fix them at the roof of the nasal cavity to have a good reconstruction. So there are multiple techniques for reconstruction and I'm focused now on the transnasal view because I think the transgranary view where the periostal layer is all clear, so I go for the transnasal techniques. There are some layer techniques that mean you need reconstruct the skull base with multiple double or three layers. You can use some autologous material like the metoterminate, like the mucoperishondrium and you can use some heterologous crafts. There is the obliterative technique we have seen yesterday in putting fat into the cellar to obliterate the whole space and I will highlight this vascular mucosa flap in the next slice, so only a video. You see this is what we call the one layer covering, but you have the impression that will not work. This is not safe, yes it may fall down, you have to fix it, but this is it's not a good reconstruction technique. You can fix it with a balloon and this is what is meant with this obliterative technique. So if you have your, this should be the sphenoid sinus, you have some leakage here, you try to put one fat piece in this defect to reduce the flow and you cover the whole space with fat and you lock it with an extra layer and we do not obliterate the sphenoid sinus if we have a very small leakage. Now these are the most more effective techniques, the double layer techniques that mean you have one layer in between the dura and the bone. This is a graft tutoblast, so a fascialata graft and you put it in between the dura and the bone and you fix it then with with glue, so this is what I meant if you put this graft in between the dura and the bone and you have some pressure coming from inside, you compress this construct and you will have a good good ceiling and if you put a lumbar drain in such a case, you reduce the intracranial pressure and this effect will disappear, so it's not always good to have this lumbar drainage and the external layer is only to prevent this intradural layer from dislocations or to prevent against the gravity and next step is a three layer technique that mean you have another intradural layer to reduce the flow if you have a large tumor or a resection hole here you can reduce with fat or something like that, you can reduce the flow and then the other two layers. Now coming to this mucoseptal flap, so the the idea is to create a large flap and this flap you can put wherever you have your your defect and again this is koane, this is the osteum, to the sphenoid sinus, this is the nasal septum, there is the attachment of the middle terminate, the nasopalatin artery is running here, so this would be the pedicle of this vascularized flap and this is a video in a cadaver dissection showing you how to prepare such a flap, the koane, middle terminate, the nasopalatin artery will run here, this is the septum and the first cut is along the floor and you can really go very very far anterior till the limbus of the nose that means where the where the skin meets the mucosa, yes this is this area and you really can go this is very very anteriorly and this was the first cut and the second cut is there is the osteum, you stay below the osteum, yeah below the osteum and then go but not cross the level of the middle terminate, stay beyond the level of the middle terminate so that you do not harm the olfactory area, in real life you can see some yellowish fibers that show you where is the olfactory area so you really can orientate at these fibers and you see this is koane, this is the flap raised, this is anterior sphenoid wall and this is again the suture here to the palatine bone so the sphenoid sphenopalatin foramen would be here, no there is there is this so sphenopalatin foramen would be here and for surgery you can place the this flap in the nasopharynx or in the maxillary sinus but avoid to twist the the flap because you have the artery can be twisted as well and then you have an ischemia of the flap. What is literally saying about this flap, this was a mono center study and it was the casam and privadello and and carot group so really expirient group in an endoscopic transnasal surgery and in the prevascularized flap area they had a CSF leakage in their surgeries up to 20% and you see after introducing the flap they reduced these incidents of CSF erinorea and with a more refinement of their technique there are now at about 5% of postoperative CSF leakage and this is a review multi center review and you see these are the CSF leakage after reconstruction and the vascularized reconstruction if possible it seems to be the best reconstruction but it's not always necessary yes and it's not without mobility so some principles one layer has to achieve the ceiling if you have you can put 10 layers if you have not one layer who is really sealed in this area the CSF will find this is this way so one layer has to be safe to achieve the ceiling the side must be prepared by removing the whole mucosa so you have to put the flap or the layers on the bone you have to smoothen the surface of the bone so that you avoid folds and that you avoid free spaces in between the layer and the bone don't use synthetic material between the layers and consider that the flap or all material strings a little bit so it have to overlap more than than only one two millimeters it really have to you have a good overlapping of the of your implants and of course you can use a combination of all those techniques you see an intradural a subdural layer and you see another layer which is the flap and then fix everything with that such a balloon catheter it's a normal urine catheter but it can be dangerous if you put it in a sphenoid sinus and you have an open the cellar is wide open you can push the catheter and all your materials against the optic nerve and you it can cause the blindness so it's you have to really think about what you're doing and it's only two cases this was a patient after a trauma with a with skull fractures and the persistent csf loss and because this was a leakage at the at the clival area we went for endoscopic closure you see there are multiple this is planum sphenoidality here this is the cellar floor this is lateral optical carotid recess midline septum and you see there are multiple fractures all around but there's no rinsing via these fractures the mucosa is removed this is carotid and see there is no rinsing via these fractures but you see there was this tiny hole and you see the arachnid is opened and this was the problem and you see you have to to smooth the surface to remove the the the septice and then we put the small piece of fat in this opening and the flap flap will will be positioned here so this is the positioning of the flap you have to look if you have the right side up and down you have to put the endosteal layer on the on the bone another that we put to to prevent a dislocation we put some fat above this and then we fixed it with glue and glue is not for sealing glue is only to fix the implants yes with glue you will never never seal a csf leak and after putting a flap we do the next day we do a MRI contrast enhanced and in a t1 contrast enhanced you can see where is the flap and if it's at the right position yes and if we have a balloon we see how much is inflated and this was the patient with these lateral sphinerida maningo seal you see there was a bulging of the lateral wall of the sphinerida sinus due to a very large system around the trigeminal nerve and this is the video again opening of the sphinerida sinus you see this is cellar floor this is midline with a with a septum and everything has to be drilled and you see there is the seal only by removing the mucosa it was evident and this is the whole bony defect yes and remember the the the sign this is septum here are the carotids here and here and this is the defect so we were afraid to push some material in between there and so we only did an overlay that meant we that meant we put again some fat and fixed it with glue and then two overlapping layers with fascia lata so this was the first one which overlays this and you see there was another small bone defect and so the other more overlapping fascia lata flap overlaps this defect and in this case we put again fat in the sphinerida sinus and and locked it with gel foam and the whole mucosa has to be removed or you will get a mucosil okay thank you