 Thanks, Kristen. Our next speaker is Evan Joyce. He's a neurosurgery resident first year presenting on optic nerve sheath fenestration for IIH Hello everyone. I just finished my full re-rotation on neuro ophthalmology I didn't get to see an optic nerve sheath fenestration I did see quite a few patients with IIH and I thought that it was a good interesting tie-over to sort of my realm with CSF shunting diversions in Neurosurgery so So to start just a little historical perspective for IIH IIH So it was first described by Henry Quinke in 1893. This is two years after he introduced the lumbar puncture He presented a case report of 10 cases seven of which were women and three men with typical symptoms of IH with elevated LP pressures He originally called this meningitis cirrhosa. It was renamed to Pseudotumor Cerebrae in 1904 by neurologist Max Non, and then in 1937 Dr. Walter Dandy out of Baltimore published a 22 case report series that he had diagnosed patients with a lumbar puncture and pneumoencephalography encephalography where he Trefined and injected air into the ventricles to make sure there wasn't a mass lesion causing elevated intracranial pressure He treated his patients with Subtemporal decompressions and this paper formed the basis for the dandy criteria in 1955 neurologist Joseph Michael Foley coined the term benign intracranial hypertension, but this is mainly to distinguish between Cases that had a malignant cause such as a malignant tumor causing mass effect And this was abandoned due to the high incidence of visual loss with this condition So epidemiology for IH so it's an annual incidence of point nine per hundred thousand persons In the US and this increases first of you strafe I by women of childbearing age from age 15 to 54 and About five times more than that if you look at that Childbearing population that's obese with obesity being defined as greater than 20% ideal body weight And if you look at patient spot with II age 90% of them are obese and 90% are women in their childbearing age and the mean age of diagnosis is 30 So this is a concerning issue because as you see on the right the CDC publishes these pictures of the US each 10 years and they have to add new colors each 10 years that they publish It's the BC epidemic rages through our country. So numerous Proposed associations have been linked to IH But some of them have sort of been refuted Through different case studies and observational studies with proper controls So things I found that were not associated with IH But are sometimes commonly thought to be associated our pregnancy irregular menses OCP use multivitamin use quadricle steroid use not withdrawal and antibiotic use whereas associated medications include Nalodixic acid, Nitroferentone, Indomethacin, Vitamin A, Intoxication Isotrentinoin, which is also known as Accutane, thyroid replacement therapy, Lithium and anabolic steroids So a pathophysiology for IH Sort of all goes back to thinking about the mineral kelly doctrine Which is that there's a pressure volume relationship inside the fixed cranial vault You have three components primarily CSF brain prankima and blood both arterial and venous and these have to equal a constant Or if there's increase in one you have to see decrease in another typically and they dictate what the IACP is going to be inside the brain So observations in IH that can point to a pathophysiology One it occurs primarily in obese women during their childbearing years to its There's reduced conductance to CSF outflow seen in it Three typically or you have to see a normal ventricular size and no hydrocephalus with trantopendymal flow and Four on histological sections. There's no cerebral edema so currently the most popular hypothesis is that there's reduced CSF Absorption and on the right you see the arachnoid arachnoid granulations where CSF is absorbed from the sub arachnoid space into the venous sinuses So other thoughts would be other things that can change that CSF Volume including increasing production increasing the cerebral venous pressure venous sinus Stenosis and having increased brain water content. However as it's called idiopathic. We still don't really know So presenting symptoms for IH The most common by far is headache so 94% of patients will come in with headache and it's typical headache That's worse in the morning. It's occurs daily. It can be pulsatile and it has associated transient visual obscurations with it in about two-thirds and Pulsatile tinnitus Photopsia and eye pain in a smaller percentage So IH is diagnosed by the modified dandy criteria and this is the Very poorly readable version from the IH treatment trial that they used So one they said that there had to be signs and symptoms of increased intracranial pressure To there's an absence of localizing findings with the exception of a cranial nerve six palsy Three there's otherwise normal neuroimaging But CSF opening pressure of greater than 20 centimeters of water For the patient has to be awake and alert and there has to be no other cause for increased intracranial pressure present and for CSF opening pressures that are between 20 to 25 There's a they they used other qualifiers that that patient would have to have so above 25 They wouldn't need those qualifiers on the bottom So as far as treatment goes for IH It can be broadly broken down into either medical or surgical treatments for medical treatments The goal is to lower the ICP and treat symptoms mainly headache These are weight loss usually a goal of 10% or more a low-salt diet using serial LPs to reduce CSF volume or a lumbar drain and Going to medications that alter How much CSF is produced or how it's reabsorbed and also have some Ancillary benefits with decreasing appetite which complain to weight loss So those include diamax topomax and furosumad Surgical treatments are primarily decompressive or CSF diversion techniques These include some sub temporal or sub occipital decompressions like Dr. Dandy used optic nerve sheath fenestrations CSF shunting procedures from ventricular to peritoneal atrial drugular or pleural or lumbar peritoneal shunts gastric exclusion surgery in patients that are morbidly obese and More recently there's been reports of venous sinus stenting to help increase venous outflow and decrease ICPs So treatment in one review paper that I saw they had a nice algorithm to help dictate Which paths you should take and the main thing that I noticed was that as soon as you start having visual symptoms That's when you move towards surgical procedures. So without visual symptoms. It's typically medical management Once you start seeing visual symptoms you move towards surgical So first it's important to understand sort of the optic nerve Anatomy to understand why a procedure like optic nerve sheath fenestrations would be helpful. So the optic nerve runs within the optic sheath, which is a Tough fibrous leathery Dural membrane and dura mater as you remember it means tough mother. So it's very tough and fibrous and so inside there There's a thin area Here you can see it on both sides It's a subarachnoid space around the optic nerve and it's filled with these arachnoid Trabeculations and the pressure is transmitted from intercranial along these trabeculations up to the optic disc head Which is supplied by the central retinal artery and the posterior arteries and the thought is that With this pressure translation you start to see optic disc edema, which we see as papillodema on exam And this is dependent on the relationship of sort of the three different pressures the CSF pressure intraocular pressure and the blood pressure and so we grade papillodema on the prison scale and as you can see From left to right you see sort of increasing from grade one With sort of a nasal and feral temporal or inferior superior to a full halo You're striking obscuration of vessels as they exit the disc Obscuration of vessels as they're on the disc in total complete obliteration of vessels in grade five So it's important to think about papillodema because it correlates to visual loss and the thought being that with this pressure You start to have axon plasmic flow stasis. You decrease the fast and slow Axon transport mechanisms. You see optic disc edema and then you develop intra neuronal ischemia And as you can see there's correlation as you increase papillodema grade you decrease the sensitivity of light perception and it incurs in a predictable pattern so 30% of patients will present with visual loss and typically it's seen first as an enlarged blind spot and Inferior or partial inferior are our cue at neurofibal boundary bundle defect and this progresses through five different grades to almost complete vision loss So optic nerve sheath fenestration so this technique was first reported by D. Wacker in 1890s or 1872 He did a blind slit in the optic nerve for neural retinitis on a patient but it was maybe more first proposed for increased intracranial pressure by Heyreyer or Heyre who performed lateral arbitotomies on Rhesus monkeys that he had and put a balloon inside there had inflated it to sort of change the intracranial pressure and he Saw that when he causes fenestrations The papillodema would go away and he stated that thus it seems highly probable that the edema is mechan mechanical in origin And so the indications for optic nerve sheath fenestration are impending progressive or profound visual field compromise or a moderate compromise with persistent edema despite maximal medical therapy and there's been numerous different surgical approaches Described for this technique. I'll show you or Dr. Patel walk us through one in just a second but What's important to remember is prior to doing these there's a couple independent prognosticators If the visual field defect is outside 10 degrees from fixation there predicts an improved outcome Whereas if surgery is done greater than six months from diagnosis that Predicts worse outcome The first three or four I think So that was the initial neurosurgery approach and then the media approaches the one that's currently used In a few years ago, we did this cadaver studies I've presented this before to you all know this Anatomical studies of distances angle safety optic nerve position super orbital fissure Important basket of structures, etc. The earlier part of this video. I have some and asked me drawings to show how complex the orbit gets They're based upon this we decided to approach this super immediately now We designed a small incision lateral approach that wasn't really well for a number of years But we kept on getting calls that the ciliary ganglion was getting primed if you're not careful You basically blow the pupil. So this is what brought us Thinking about a different approach and so this little Cartoon thing that I did shows my approach to the supra oblique medial Tenant capital tendon. That's essentially your your approach. It's amazing how much of a space there really is between them Super oblique 10 millimeter campus. There's a lateral approach with the level can talk to me And then there is a media approach There's another one which is very popular in Asia where they split the whole island And they go on the wolf of the orbit. So there's about six or seven approaches including the neurosurgical one. This is a sketch drawing of Two or three quick cases here You do it through eight or nine millimeters these days in the early days. I was using 1.5 centimeters You become a little bit better. It's time goes by a blood dissection The one very many vessels this will be your orbital fat component There are some superior branches of the supra or public vein, which you can separate bluntly This is a blood separation. It's a general surgical approach Operating the abdomen It works really well in terms of opening up Cornice septi without Terry. You will not get a bleeder in the orbit if you use a separation technique And that's my go-to technique in orbital symmetry. So here's the anatomy This bears some discussion of your really lovely surgical technique, but it shows all the relative anatomical landmarks So there's a lot going on in this very complicated super media for the orbit And if you pretend like you're going for the media rectus muscles I used to get lots of phone calls from people all over the world. I'm in the orbit I can't find the nerve and so I started telling them pretend you're going for the media rectus muscle If you do that the nerve shows up there. It is in all its glory. You get a nice 70 meter, 70 meter and a half Exposure that's just to show the the surgical approach as far as the fenestration goes. We've just finished developing a surgical punch It's in a trial phase right now It just makes this whole thing safer and easier. So you make the initial cut Here, I'll show you a scissor technique, but now we've got a punch Which we just put it to that little slit and you punch two or three holes like you do the glaucoma glaucoma punch. We just had to design a different angle, a different cutting, because sclerar and the duro can carry different sort of degrees of thickness and tensile strength to cut This is a bit more primitive where you're cutting a larger window Pulling the sheath forward so you don't traumatize the nerve and you can get a very large portion of the sheath You can do it with headlight and lutes or you can use the microscope either way can pretty good Thank you, Dr. Tau. Yeah, so it's a great video to demonstrate the anatomy and the approach So We do optic nerve sheath fenestrations because it's been shown to improve visual acuity and visual fields So there's many case reports of doing this technique But there's no great prospective trials of surgical versus medical therapy nor other trials Prospectively unilateral versus bilateral optic nerve sheath fenestrations. We do see in this cohort of Studies that were greater than 25 patients. There are 74 percent increase or stabilization or improvement in visual acuity and 87 percent in visual fields So unilateral versus bilateral is a good question and there was a study published in 2011 at a University of Iowa that was a retrospective review and they took 78 patients and they that had optic nerve sheath fenestration 62 of which were bilateral and They massed observers and had them rate the prison score a grade at two weeks three months six and 12 months fall And what they basically saw is by doing a lino lateral They saw a decrease in both eyes initial pre-op prison score of three to point five For the operative eye and two to one for the non-op eye So it's slightly less decrease in the non operative eye But still a decrease whereas in the bilateral or patients They saw it equal for both eyes and they did see the visual acuity in fields improved at 12 months So the final question is a CSF shunting versus this fenestration So again, there's a lack of randomized controlled trials to guide this and it's very institutional and surgeon heavy or dependent Typically depends on severity of visual loss and the severity of symptoms But there's a good review looking at this and talked about optic nerve sheath fenestration Improves headaches in about half of patients and you see improvement in stabilization in the acuity in fields in Very high percentage is about 90 percent Whereas complication rates range from five to 45 percent and typically these are transient CSF shunting on the other hand, there's typically count comparing VP shunts to LP shunts and they have seen in retrospective reviews that there's not much difference as far as improvement of symptoms There is greater improvement of headache than visual symptoms But they shunting does not have a insignificant failure rate revision rate or infection rate up to 51% of patients in one study required re-shunting and 30% required multiple revisions over 10 years nor is it cheap So the incidence has gone up 350 percent But it costs about $12,000 and $10,000 to do a VP and LP shunt respectively So the trend right now is for optic nerve sheath fenestrations for visual loss in shunting for headaches Any questions Do you know how much So last December what I presented in Australia December called last We took a poll of all the advantage of Southeast Asia Australia is every certain shows up to your meeting So we had a zero percent uptake in December of 2014 We just did an internet survey and the uptake is 60% in Australia It's just a matter of teaching and showing the anatomy The commonest question I get is I'm in the orbit So we're cleaning up some of our videos Academy websites to show And then we're making the instruments easier. We've designed this thing Patel punch one two three Like Move it since helping me design some retractors that will allow us to get it to the orbit safely Yeah, so I had about four videos at the end of that and some of them are pretty impressive You can get as large a sheath You know as an aside the thing that's really made a difference. I mean, this is a good technique I'm proud of it. We've cut down the combinations and finished reviewing the last hundred cases We now remove intraocular retinal mastoma tumors So we now get a centimeter to two centimeters of optic nerve So touch wood today, we've never had tumor beyond the cut end of the optic nerve Which happens in about eight percent of cases around the world. So you condemn these children to radiation give authentic So it's a really exciting effect. We can use this approach They asked you a question is a big egress of fluid depending on how much fluid there is So we get another sound ahead of time for Judith and Kathleen asked me to do a demonstration Usually pretty impressive. Well, if you want to see it, I've got some videos Just as a quick follow-up, do you ever get persisted? Yeah And there's a lot of fluid What about late it's like late weekage Demonstrate official cases I See I can answer this without Without invoking any studies, but I've seen lots of movies post-ops And I don't think I've ever seen a new persistent period As a matter of fact, I've never seen any period organ Latina here's hardly even cruising but Weirdly you think all that fluid You think and yes No, I mean the patients asked well, where's the fluid go? You're I don't know, but it doesn't come out before forward. That's I've never seen a patient with any kind of So there is one study we do need to do prospectively That study presented about apple versus you To look and see what the effect is on the opposite after we do only one side we'll talk about that I'm not a little pro forma We can look at this. I talked to your previous fellow We never got anywhere There's a paper at the Academy last year. They talked about cystic Optic nerve sheets Collections after peristation as you know many things in plastic surgery are technically better. These people claim something like 40% 35% cystic Formations behind the globe after peristation, which implies Fibrous encapsulation with compression now as far as I know I've never seen that Who we have they actively gone and scan these patients looking for it. I think it would be ethical to scan them Unless you have a problem, so I don't think we've ever had that these people I'm claiming 35 or 40% I think that must be Many people do slits