 Hey everybody. So I'm going to introduce our first lecture. This is Jason Foyerman. He's one of our Koria fellows. He's been a great fellow to work with. I've learned a lot from him. He did his medical school training at the University of Michigan. And he did his residency in ophthalmology at Baylor. And today he's going to talk to us about DMEX. So without further ado. Thanks, Renee. I'm all wired up here. So we have started transitioning to doing some DMEX. And I'm going to talk a little bit of background about DMEX and pros and cons of the procedure. And show a video of our first case with Dr. Mifflin and some of the lessons we learned. Okay. A little background. Endothelial keratoplasty. We do it for a variety of reasons. The most common nowadays would be foots dystrophy. Followed by pseudo-fakie grade, fakie bolus keratopathy. After cataract surgery, this is decreasing in incidence because of the advances in technology in cataract surgery. The rest of this group are patients that we operate on much more rarely, but anything really affecting the endothelium, posterior polymorphous dystrophy, ched, eye syndrome, and endothelial failure from trauma or prior surgery, which is kind of gets grouped back to that one, or ill prior penetrating keratoplasty. Prior to endothelial keratoplasty techniques being developed, which have really been only around less than 15 years, the old solution was to do PK, full thickness penetrating keratoplasty. There's obviously some risks that come along with that. It's an open-sky surgery. There, anytime the eye is wide open, there's risk of expulsive hemorrhage, which is, that's what this is a picture of happening in the back there, slowly. Infection. It's a longer recovery. We counsel our patients that it's going to take a year to rehab their eye. Sometimes it's shorter. There's risk of the hisses in the future. Once we've made that full thickness wound, it never gets back to full strength. There's risks associated with sutures, infections, abscesses, and there's more refractive unpredictability and astigmatism with full thickness penetrating keratoplasty. This is a cool slide that shows the evolution of endothelial keratoplasty over the past 15 or 13 or so years. The first procedures performed in the United States were these D-LEC procedure, deep lamellar endothelial keratoplasty, had a variety of problems. It was also very technically difficult. What was done here is actually a deep, intrastromal dissection on the host, which was technically challenging. Then that was also manually done on the donor and it was stuck on. There's issues with interface, irregularities, astigmatism. But it was the beginning of this evolution of this evolving technique that we do now. DSEC is depicted in the second OCT here. That was basically with the start of doing decimetorexia. So instead of doing a deep lamellar stromal dissection in the host tissue, just strip off decimes membrane, which allowed for a much more clean plane to adhere to on the recipient side. Initially it was a DSEC, D-S-E-K. Then the A, decimates stripping, automated endothelial keratoplasty, came in when we started using microkeratomes to cut the donor tissue. The focus of this talk is DMEC, where we do just a replacement. Instead of including a little bit of posterior stroma, we replace just decimates membrane and endothelium. You can barely even see any graft on this photo here. This is sort of the newest, but there's not a lot of data on it. It's not really taken off yet for a variety of reasons, but this is to make where it's kind of a hybrid between DSEC and DMEC. There's included stromal tissue in the periphery, but the center is pure decimates. These are much more challenging to prepare in the iBank. This is also challenging to prepare in the iBank, and I'll show some videos of that. That's probably the primary reason this hasn't taken off. The goal of DMEC is to get rid of some of the challenges surgically with DMEC in handling the tissues and giving it some structure to work with, but I won't focus on that. The advantages of endothelial keratoplasty in general are basically all the disadvantages of penetrating keratoplasty. You don't have a 360-degree penetrating wound. You just maintain the structural integrity of the cornea for the most part. It avoids inducing high levels of astigmatism like you get with penetrating keratoplasty. There's faster visual recovery and a lower rate of graft rejection. So, DSEC versus DMEC, this study looked at patients with who received a DMEC in one eye, a DSEC in the fellow eye, and looked at them one year after surgery. The average best-corrected visual acuity was better in the DMEC group, 24 versus 2032 in the DSEC group. 85% of patients preferred the visual quality in the DMEC eye. 85% of patients reported faster visual recovery in the DMEC eye, and there was no difference in endothelial cell loss in one year. This study is from the Frank Price group looking at rejection rates in the first two years after surgery. DMEC way down there, 0.7%, DSEC was 9% in this group looked at, and penetrating keratoplasty is 17%. So, it's lower rejection rate with DMEC as well. But then this number in 2012, 22,000 DSECs performed in the United States in only 748 DMECs. And so, why don't we have more DMECs in the United States given those results? And the procedure is, it's more difficult, it's more time consuming. The rebuttal to that is there's new, more standardized techniques that are emerging, so we're getting better at it. There's risk in preparing the donor tissue when stripping it in the R, which could mean lost dollars and lost tissue, which is a limited resource. There are emerging standardized techniques for that, and high banks are pre-stripping tissues, so the surgeon performing DMEC is increasing because that takes some of the burden off of the surgeon to have it pre-stripped. The re-bubble rates were really high initially when we started doing DMEC with the use of SF6 gas instead of air. It seemed to be decreasing. And some may ask if the patients are already happy with DSEC, why change? And one study demonstrated they do have better quality of vision. They have less higher order aberrations, but that can be argued either way. Patients who are not good quality candidates for DMEC are patients with glaucoma surgery, blebs, tubes, anything really, any hardware in the anterior chamber because the DMEC tissue is like wet tissue paper. It just, you know, it breaks easily, it's hard to manipulate as you'll see. So any ACIOL, if they have a poorly constricting or damaged pupil with inadequate iris support, you've got to have some sort of support behind it to get it to unroll in the anterior chamber if they're aphakic. DMEC has been lost into the back of the eye. And because we're using SF6, if there's a short post-operative period or mountain travel really for that matter. This is a photo that comes from, this is from the Portland EyeBank lines vision gift showing their pre-stripped tissue, how it comes. So they pre-stripped this area over here and then they leave just a little hinge attached and notch the scolera so you can see where the attached area is. So this, the introduction of the EyeBanks doing this pre-stripped tissue has started to increase the rate of surgeons doing DMEC in appropriate candidates. Our EyeBank here is working on being able to pre-strip tissue for us as well and then your future, that's a goal of wades in the near term. This is a video courtesy of Lions Vision Gift in Portland, Oregon that shows the process of stripping the tissue. The tissue is mounted on a tree fine and the periphery is scored. The tri-pan blue is added for visualization and the edge of decimase is just carefully under BSS, put back down in position, refloated and then put back in the optosol and ready to go. Made it look easy but it's easy to lose tissue during that to tear the tissue. Analyze with a specular microscopy to make sure. So the surgical procedure has some similarities to DSEC but there are some notable differences. There's a smaller incision because we're injecting the tissue in the scroll through a smaller injector, through a smaller injector, three to three and a half millimeter incision. We make a decimator axis just like we do in DSEC but the key difference there is that we make it larger than the graft as people feel that. If there's overlap between the DMEC and the edge of the strip decimase, that's more likely to detach. We want a soft eye when we're injecting because the material is very hard to manipulate. It moves around and if there's any sort of pressure from within the eye, once you take the injector out it can squirt right back out of the eye. A small pupil, you want to lose it posteriorly. You need some sort of platform to work on to help unfold it because it wants to scroll up and we make a PI inferiorly because we're using SOC. So as you can see once you strip off the tissue it rolls into this nice tight little scroll which is perfectly difficult to work with and conveniently the endothelium is always on the outside. It'd be nice if it would protect itself but it's just on the outside to be knocked around. This is the strip and stain decimase being sucked into a glass injector and it's felt that the glass injectors are less traumatic than some of the earlier plastic ones that are less traumatic to the tissue, to the endothelium. This one was a modified Jones tube that was developed by Mike Stryko in Portland where the Jones tube was just enlarged to create a reservoir for the tissue to float around inside. Once it's inside the eye then the dance begins to try to unfold it without touching it and there are now a variety of sort of standardized techniques that people are using. This is a photo from a paper by York describing some tapping techniques but basically little fluid bursts through the paracentesis can help unfold one side keep a shallow chamber so that once you do unfold one side of the graph that it stays unfolded and a finger on the side of the eye as you can see here can modify the chamber depth while you're working with it. Taps on the surface of the cornea are used to direct fluid waves into those scrolls to try to get them to unfold. If there's a double scroll tapping right in the middle will send fluid waves out into those to unfold them. If you have one side unfolded and one side scrolled up if you kind of hold a cannula on that unfolded side to keep in place and tap across and unfold that scrolled side and then little burps of the wounds if there's one little edge that's being troublesome and happens to be right next to a paracentesis or the wound burping a little fluid out of there can kind of get that last little bit to unfold. Once it's inside the eye orientation is important and it's sometimes difficult to tell the direction in which the graph is oriented. There are a few tricks that have been described. One is actually putting the S stamp on the graph. The EyeBank does that and that helps if you can see it inside the eye that helps confirm that you're going in the right direction. That's probably the easiest method. But people are using handheld slit lamps to check their orientation and then there's this Mutsuri sign where you take some sort of cannula and put it on top of the graph and move it either to the left or to the right so that it's under one of the scrolls and if it turns blue, you know you're covered by the scroll of the graph and you're in the right orientation. If it doesn't change colors when you move left or right, you know you're like this picture where the graph is upside down. Post-operatively, these are some good photos of what a detached graph would look like. Here it's a Demidas and OCT. You can see the graph detached over here. This is a properly oriented graph that you can tell because it's trying to curl that way. So the endothelium is on the right side and plus you can tell it's working over here. But then after re-bubble, it sticks back up. This is an example of a upside down graph. You can tell that again because of the curling of the graphs. It always wants to curl with the endothelium on the outside. So the endothelium is on the corneal side here. So this graph would need to be flipped over. So now I'm going to go through our first case which was a humbling experience but we learned a lot from it. So I've sort of been making a approximately three and a half millimeter incision. And this is shown with Dr. Mifflin's permission. I'm not sure if he's in here. So I'm going to make a shelved one just like we normally do with DSEC. Just a little bit smaller. Our normal three paracentesis that Dr. Mifflin likes to do with DSEC. There's some variations to that. And here we're injecting viscoelastic in Helan plotting out our area that we're going to strip decimals. And now he's putting a little Helan under the iris and that's in anticipation of making this PI here. We've taken a bent needle and a Sinsky hook. Stretch the iris there. Decimatorerexus, this wide area. And decimals are removed. And now we're just checking the size. That's that Stryko modified Jones tube. We're just checking the size of the ejector. It wasn't fitting quite as we wanted. So enlarging the wound a little bit. IA, we've got a little iris coming out because we've enlarged the wound. But a little myacal bring it back in and bring the pupil down for us. And now here's our graft. It's been stained with tri-pan blue. And we're lightly tree-fining. We used a 7.5mm tree-fine here. And the outer rim, the untree-fined rim is being removed now. It's just the graft in the center. And that little circle that you'll see is free-floating as we squirt BSS on it. That is a little, oops, that's a little stromal button that used to be in that opening there. And that's where the eye bank had removed a piece of stroma to put the S-stamp on this graft, which unfortunately is not very visible, but that's what that came from. And because of where we had tree-fined, it had kind of come around. It ultimately won't prove to be much of a problem, but that was one thing we noted that we could have avoided in this case. And so now the tissue's being stripped. It's pre-stripped. This is actually from a different eye bank. This was actually pre-stripped peripherally and was still attached centrally, but it doesn't really matter there. It comes off and scrolls tightly immediately, and we placed it in some BSS here. It's not very well stained, so we're going to add a little more tri-pan. And after a little more BSS, it gets sucked into the injector. And so we thought the hard part was going to be unrolling it in the eye, but just getting it in the eye was really the most challenging part of this particular case, as you'll see. So we're softening the eye, letting out a nice soft eye. We don't want to inject it and then have it squirt right back out our wound. And here we are injecting. You'll see fluid going here in a minute. The graft isn't moving. So we ran out of BSS. So we deepened up the chamber, filled our tube back up with BSS, and tried again a little movement, but then we ran out of BSS again. So this time we're going to go in and figure we should turn the bevel of the injector up so that we're not bumping into iris, bumping into anything. So then hopefully it'll come out. And I'm going to stop the video right there. You can see the graft is right at the edge of the injector, but we're going to go in and bevel up. But because the graft is right at the edge, this is another learning point, unfortunately as soon as it touches, it just comes right out. And so now we're half in, half out, a little BSS and take it back out of the eye and now the endothelium is really mad at us. But fourth time's a charm. The bevel turned kind of sideways. Nice deep chamber, not still a soft eye though. And we inject and it goes right in. And actually to our delight, it ends up perfectly centered and half unrolled. So now we don't have that much more work to do. Suture the loon of letting a little bit of fluid out of that paracentesis and gently tapping and directing fluid waves in that direction. Now we get a tone roll pretty quickly actually. And so here comes SF6 under the graft. Now we didn't really pressurize the eye as much as we normally do with desec. And we think maybe we should have really pressurized the eye and then let out a little bit of the SF6. In the words of Dr. Mifflin to seat the bead because I'll go through the post-op course here. The DMEC was in place on day one. There was a little bit of separation inferiorly. It stayed attached superiorly in day four but then the inferior 30% was starting to come off. On day six it was 50% detached. So that's when we pulled the trigger to re-bubble. So when we re-bubbled it, we kept the eye nice and pressurized for a few minutes. Really pressurized it back up. And it actually stayed attached since then but was slow to clear. Obviously there's a lot of trauma to that endothelium. Although she was last seen on the 18th of May which is now posted on month four. The DMEC was still attached and there was still a little bit of a demon but it continues to get better actually with every visit. Surprisingly in her vision it's now 2040 uncorrected. She's happy she actually called Dr. Mifflin this week to tell him that the DMEC guy is now seeing better than the other eye. She's ready to go on the other side. She had fuchs, I don't think I said that. Lessons learned. We had a little iris prolapse because we went to IAA after we had already enlarged the wound so that could be avoided by getting one before. We had that little stromal punch that was floating around on top of our DMEC while we were trying to strip it and that could have been avoided by refining not on top of that particular area if we moved to the side a little bit. The S-stamp actually didn't really show up and we're not sure where we kind of lost its clarity but it would have been nice to have that to confirm our orientation one more time. I didn't talk too much about that but it was actually easy for us to see in the OR that it did seem to be oriented appropriately as it was sort of auto-unfolding there when it came out. The biggest problem we ran into was in the injection and we now realize we need at least some chamber there and the bevel needs to be turned so it's not facing against the iris or any other tissue so that there's some room for the graft to come into the eye and a nice tight seal around the wound so that you don't lose fluid around the outside of that there. It's attached and we thought we would have been better off by really pressurizing the eye for a few minutes during the initial surgery and hopefully pushing up the graft a little bit better. And so in conclusion, D-MEC is a true anatomic replacement for patients with endothelial dysfunction, has a potential for better visual quality and lower incidence of rejections versus DSEC but there's a steep learning curve. How are the techniques being standardized? Questions? Oh yeah, I think it's the number that I've read. And so it's easier to unroll. That's basically what I've read about. Is that what you were... Yeah, I mean, I guess the problem is sound but the problem in this case is you really need that and I don't know what other options there are out there. Dr. Roscoe has some comments. So this is actually directed to the residents. I was unable to be there on Friday and I was overwhelmed and humbled and just so appreciative for the Faculty of the Year Award and I didn't know about it and then it was kind of funny because Elaine and Lynn and Alicia were all emailing me because I was stuck in Texas at a business meeting and I thought something was up so that's why I emailed Randy and I just said, Randy, I don't know what's going on but please explain that I can't be there and I actually had it on my calendar for two months as soon as Alicia had sent out the whole of the date. It was on my calendar but I just wanted to say that I think to be able to work with you is such a privilege for us as attendings and to be able to teach you is really... it's really a privilege and an honor and the fact that you gave me this award sends a tremendous message back to me at what I do.