Learning a new surgical technique can be daunting, doubly so when the tissue must be prepared by the surgeon! Register to begin the transition to DMEK. The webinar is led by Dr. James Lehmann, who has performed over 300 DMEK surgeries and has taught surgeons in Peru, Israel, India, and China. Some of the critical steps that will be addressed include preparation of the donor tissue, selection of patients for your first cases, and key intraoperative principles.
Lecturer: Dr. James Lehmann, former Orbis staff ophthalmologist (2005) and current cornea surgeon at Focal Point Vision in San Antonio, Texas, USA
DR LEHMANN: Good morning, everybody. I’m Dr. James Lehmann. Thanks for joining. I’m gonna try to get everything going. Okay. So good morning. Welcome from San Antonio, Texas. I hope your Mondays are beginning nicely. We’re gonna talk about the transition from DSEK to DMEK. A little bit about me here. I’m in private practice in San Antonio, Texas. I do a mix of cataract, cornea, and refractive surgery, and mostly DMEK these days. And I’ve had the fortune to work many times with Orbis and with SightLab doing training programs about DSEK, DMEK, and PK, most recently in India. So I have experience teaching and doing wet labs and such. We’re gonna go over the background: How to pick donor for DMEK, how to evaluate the patient, prepare the donor, what instruments are needed, how to prepare the recipient, load the donor, and the steps for surgery. Before we get started, we’re going to do a few preliminary questions. Just so I get an idea about the audience skill level and experience level, I want to know if any of you have performed any DSEKs. And we’ll give it a few seconds and Lawrence will show us the results here. Okay, so most people here are just learning. Okay. We’ll go to the next question. How many DMEKs have you performed? Sorry, I’ll go back one slide here. Here we go. How many DMEKs have you performed? All right. The next one would be: I have access to prepared DSEK tissue. So this would be that your eye bank is able to prepare DSEK tissue for you to use. Or do you have to harvest the tissue and prepare it yourself? Okay, most of you have an eye bank that gives you availability for that. The last one is: my eye bank will give me prepared DMEK tissue. Okay, about 50/50. Now we’re just gonna do a few questions about what we’ll talk about today. Which of the following would be a contraindication to DMEK? A patient with an Ahmed tube, an aphakic patient, poor view, iris defect, or peripheral anterior synechiae? So which one you couldn’t do a DMEK in? We’ll get the results here shortly. And we’ll go over all of this too. Okay. Keep moving along. So a cornea preserved in Optisol can be preserved for 5 days, 10 days, 14 days, or 18 days? Okay, that’s correct. And my talk somehow disappeared. One second. Where is my keynote? Sorry, guys. Sorry, Lawrence. There we go. I got all these closed captions instead. Got it, okay. All right, and last question: In DMEK/phaco, what should the refractive target be for plano results? Should you aim for -2, -1, plano, +1, or +2? I’ll look at the results here briefly. That looks pretty good. Moving right along. So background: This is what keratoplasty was in the ’40s. This was a graft done with a square graft. You can see it’s not round. They used a double knife, and would prepare these in either steel or silk sutures at the time. And this is what we had. For any kind of corneal disease, until the early 2000s. So it was one size fits all. And as endothelial keratoplasty evolved, now we have so many different kinds of options. But it was first performed in 1998. Dr. Melles doing a PLK, showing an air bubble could be used to stick tissue to the cornea. Then in 1999, a DLEK, which was very difficult. You had to do posterior trephination, so it didn’t catch on. Until 2004, when microkeratome was used to prepare DSAEK tissue, decreased the learning curve a little bit, and made it easier to adopt. That’s picture B here. And Dr. Melles in 2007 did the first DMEK, where we’re just doing anatomic replacement of the diseased tissue. DMEK is precise anatomic replacement. That’s a post-op day one cornea. How clear it is. They have better vision and less refractive shift than PK, but there’s a learning curve and possibly fewer candidates, because of the surgical steps. It requires mostly normal anterior segment anatomy. So here are some statistics from the EBAA. That’s our United States association of eye banks. And you can see the number of PKs is pretty stable. And you can see the number of DMEKs increasing. So from 2013 to 2017, the number of endothelial procedures has stayed about the same. Okay? But the percentage of DMEK has gone from 6% to 26%. So it’s definitely growing in popularity. And so how do you know if you’re ready to start doing DMEK? First of all, you have to have some experience. A cornea fellowship, either a short-term one or a full year, and you have to have some experience doing penetrating keratoplasty. I would suggest at least 25 to 50 PKs, to give you an idea about how to hold and manipulate tissue and sutures as well, and at least 25 DSEK. Now, the skill set involved in DMEK is different than DSEK, and a lot of surgeons now learn it at the same time in the United States in their cornea fellowships, but what DSEK teaches you is about air management, bubble management, how to pick the right patients, how you can deal with postoperative complications and such. So I think it’s important to have done DSEK prior to learning DMEK. And then most importantly, you need to participate in a wet lab. Either with somebody in your local country, who’s got experience with this, or attend one of the national or international meetings. But you have to learn about donor preparation, especially if your eye bank can’t prepare it for you. And that’s a skill unto itself that requires practice on research tissue. You also have to learn how to load the donor. And you have to learn about graft manipulation. You can do all of this in a wet lab, so when you’re ready to do your first cases, preferably under the supervision of an experienced surgeon, that you’re able to have that success that you desire. A little bit about donor selection. Because it is different than DSEK and PK. DSEK and PK are pretty similar type criteria. You want a young, healthy cornea, with these nice numbers here on the side. Many of you already know about these. In the United States, when we’re offered a cornea, we receive a tissue detail form like this. And what’s nice now is I’m seeing the endothelial picture. We used to get a count, and the counts are not always accurate, but the picture is, and you can see uniformity of endothelial cells, nice shape, and this makes you very confident that it’s a good cornea. They’re able to repeat the corneas fast to take nice pictures like this. That’s something we only had in the past few years. You want age of death to be 15 to 65, 12 days or earlier, D to P if it’s refrigerated, 20 hours. 10 hours if not. DMEKs are a little different. Here we don’t want young corneas. The scrolls are too tight and harder to harvest. 45 to 65 is the sweet spot for me. We don’t like pseudophakes, because preparation can be difficult. There can be some cuts in the endothelium that you can’t see. Diabetic donors — there’s a little bit of controversy whether there are more tears during preparation. I think this is not an absolute contraindication. But especially when you’re preparing tissue for the first few cases, you don’t want to use a diabetic donor. Some important studies about corneal tissue. You know, the corneal donor study showed us that you can use older corneas, and more recently the corneal preservation time study showed that you can have success with DSEK, with any age corneas from 0 to 14, and there was no significant difference in the results, the primary graft failure or 3-year survival rate, up to 12 days. So for many of you, who live in countries where you import tissue from another place, I know there’s always reluctance to use corneas after 8 days, but the data show that up to 12 days you’re not putting yourself at any disadvantage. So I would encourage you to use cornea tissue up to 12 days. The different preservation solutions. The most popular now is Optisol GS. In the United States, you can ask for it with amphotericin B in it. There’s a little bit of debate about how useful that is, but I know in other places you use the MK media, just because the corneas are used so fast. The preoperative evaluation. The decision here, since we’re talking about transitioning from DSEK to DMEK, is: Which one do I do? What type of anesthesia do I use? And how well does the patient cooperate? So when you’re trying to assess, to do DSEK or DMEK, you want to determine how difficult the case is, how complex is the anterior chamber, how clear is the cornea, how easily may I be able to maintain and control a bubble. For me the contraindication to DMEK would be having an ACIOL. You have to switch it out. Never forget that DSEK is a good option. We’ll get into this a little bit more. How to decide? This pain scale I have here is not postoperative pain scale for the patient. It’s how painful is the surgery for the surgeon? How extensive is the chamber? Was there a history of angle closure? Is the eye small? Is there any possibility the patient has vitreous prolapse? Is there an ACIOL present? How clear is the cornea? Most of the time you can improve the view tremendously just by removing the epithelium, but you want to get an idea if there’s extensive scarring or not. Lastly you want to talk about bubble management, and that would be: Are there iris defects? Is there hypotony? Would there be ways the bubble couldn’t be maintained firm in the anterior chamber? And lastly you want to assess the lens status between proceeding with the posterior chamber lens, or doing phaco, or IOL exchange if there’s a problem with the current lens. Here are complex cases. You have an old style ACIOL with corneal edema, here a modern Alcon style IOL, here extensive scarring, here aphakia with iris defects. All of these might not be the greatest candidates for DMEK. So you could do DSEK, depending on the age. You also could do a staged procedure, in which you remove the ACIOL, suture the PCIOL to the sclera, and proceed with surgery. You want to do pre-op OCT in complicated eyes. This is gonna help you plan your surgery and make sure you don’t have any surprises when you start your surgery. It’ll tell you if there are any membranes, how extensive are the PAS, et cetera. So I recommend this, especially when you don’t have a great view into the anterior chamber. We’ll also talk a little bit, in this preoperative management, about lens management. So you can do a combo case. That would be if the patient is phakic with a cataract. If they’re pseudophakic, what I want you to do — you want to dilate that pupil and verify the stability of the IOL. If it’s a pseudophakic bullous keratopathy patient, you need to verify the IOL is nice and stable. If they have an ACIOL, you can do DSEK or you can replace it, but you cannot do DMEK in a patient with an ACIOL. I’ll say that and then I’ll go to the next meeting and see somebody do a DMEK with an ACIOL. If they’re aphakic, I would recommend a secondary IOL, and then DMEK or DSEK later depending on the parameters. So when you’re doing cataract surgery in combination with DMEK, there is hyperopic shift, but not as much as with DSEK. You want to aim between 0.5 or -1. I would suggest a single piece acrylic or silicone IOL, and you need to be aware there’s gonna be change in the axis and the magnitude of the astigmatism. So this is a little bit unpredictable. I’m doing a paper right now trying to figure out if there’s any kind of pattern in this, but I wouldn’t go with toric or multifocal IOL with this, unless they had a lot of astigmatism and you were just trying to debulk it. So often the cataract is harder than the DMEK part. This is a case of a dense cataract, and corneal edema. You have to avoid any complications during the cataract part, because that will set you up for failure with the DMEK part. So no tear in the anterior capsule, definitely no tear in the posterior capsule. You have to make sure and be diligent that there’s no residual cortex or nucleus, and there’s no iris damage, because that can cause bleeding and make the phaco part more difficult. We’re not gonna show the whole video, but I just wanted to demonstrate the difficulty in the view. There’s vision blue there, tiny pupil, dispersive viscoelastic. So I have to be an experienced phaco surgeon to do these types of cases. Otherwise you could have the best phaco guy or gal at your institution do the case and then come back later. There’s no shame in doing a staged phaco-DMEK at all. In fact, in your first cases, you definitely don’t want to do these combo cases, because they’re much more difficult, in terms of getting the graft to behave nicely, because you don’t have a tiny little pupil. I’m gonna fast-forward a little bit here, just to kind of show that the phaco part is really the hardest part in these procedures. All right. So if somebody has a failed PK, oftentimes you want to determine: Would they be better off having just a full-on repeat PK? Or can you just fix the endothelium? There’s always issues that go into this, but you can do DMEK in these cases. They’re difficult because you have to strip inside of the margin, without disturbing the graft/host interface. Also you want to make sure that you measure the diameter of the graft, and when you order the tissue, if you’re ordering the DMEK from the eye bank, you need to order a smaller size than this, so that it can fit. The main determinant in this, which would be for a different lecture, is if the patient had a lot of astigmatism, or very irregular surface, you’re probably better off just repeating the PK, because that’s gonna be an issue, if you just do an endothelial keratoplasty. But if they were seeing well in glasses or contacts, an endothelial keratoplasty alone is probably a better idea than a repeat PK. Again, that can get a little complex. So this would be glaucoma surgery. This is probably the second most common referral I get. Patients had multiple glaucoma surgery, and now has corneal decompensation. You can do these — these pseudophakic cases can definitely be done with DMEK. You need to have experience. They’re harder cases. Sometimes you have to trim the tube. The view may be poor. You need to do gonioscopy, assess the extent of PAS, and you have to think about the visual potential. If this is a counter-fingers eye, a 2400 eye, maybe they’re better off just doing a DSEK, if you’re more comfortable with that technique. Nobody has looked at survival rates of DMEK versus DSEK in patients with tubes. But they don’t last long in these eyes either. They last five years, if you’re lucky. So it would be interesting to find out, as more and more people do DMEK, if DMEK ends up more successful than DSEK in these eyes. The anesthesia I would recommend would be peribulbar. You want to make sure the patient can lie flat, in case they need to — so they can position after surgery, and additionally, so they can lay flat in the clinic, for a rebubble, if they need it. The best first cases are patients with Fuch’s dystrophy, in cases with good potential, in eyes that have just had cataract surgery, or are gonna be staged cataract surgery and then DMEK. You need to avoid eyes with complex anterior segments, and I like to perform iridotomy with a YAG one week later. You can use a vitrector during the initial steps, not with fluid coming in — just using viscoelastic in the anterior chamber, and using I and A cut. A lot of doctors do it that way, especially if the eyes that you’re operating on have very poor views. So we talked about the anesthesia. People do these under topical anesthesia, but I prefer peribulbar. And again, patient cooperation. They need to be able to lie flat. They also need to be able to tolerate a rebubble in the office, just with drops, if that’s gonna be necessary. So it’s good to have that talk with the patient. And we talked a little bit about the ACIOL. Which ones would you leave in place? This goes for DSEK, not DMEK. But if the eye is quiet and they’ve had the ACIOL forever, they have normal pressure, and maybe the other eye is blind, and this is their only eye, like a 90-year-old patient, you probably don’t want to do a staged suture in which you have to suture an IOL and then do DSEK or DMEK. Especially if they’re on anticoagulant medicine, because sewing IOLs are rough surgeries, and they can be on a monocular patient — they can be risky, and they may not be able to stop whatever anticoagulant they’re taking. So again, there’s a lot to consider, but the main take-home point is: If the eye has been quiet, and the cornea has decompensated just because of proximity to the ACIOL, especially if they’re monocular, you might want to just do DSEK, and not the staged procedure. Here are some old style ACIOLs we see sometimes. And just like I said, if you’re gonna do an exchange, I prefer to do it in two surgeries. I like to do an IOL exchange with a sutured IOL, and then either a DSEK or DMEK. I feel like if you combine them, it’s a very big surgery, and there’s less chance of success for the graft. So that’s what I vote for, is a staged surgery, when you’re gonna do an IOL exchange. We talked a little bit about aphakia, trying to determine if you can do an EK or a PK. You’ve got to first determine if there’s a need for an IOL, and if so, then again the staged procedure. If not, you can do DSEK in this. Easier in my opinion, because you can put a safety suture through it, and if the eye has been vitrectomized, it’s easier. Here’s a picture of Cinderella in the glass slipper that doesn’t fit the stepsister. When is PK better than endothelial keratoplasty? In some cases, it is, when there’s a lot of stromal scarring or haze. If the patient’s had bullous keratopathy for years, the view is awful, and a lot of times I’ve done DSEK or DMEK in that patient, and it turns out they don’t see well, because I underestimated the extent of the stromal scarring or haze. If there’s high astigmatism or irregular astigmatism, they may be better off with a PK. So preparation of the donor. The way this has evolved in the United States, is first we used to do it in the operating room. It’s evolved now where the eye banks in the US do it. And the reason for that is because of time, money, and risk. If you tear a donor, you’re responsible, or your surgery center is responsible for the payment on that. And that’s not the case if the eye bank prepares it. It’s kind of evolved even further now, where they stain and mark and load it for us. So now I’m getting my DMEK tissue in this bottom picture, prestained in a glass cannula. So a little bit more on the preparation. This is the technique that I still use. You start by using what’s called a Bechert Y hook. What is it sitting in here? This is a viewing chamber, a plastic viewing chamber, under an operating microscope, in Optisol. And what you’re trying to do here is you’re trying to go about a millimeter inside of the limbus, where you have a clear zone, and you’re scoring — and now I’m gonna start speeding up the video — you’re scoring Descemet’s all the way around here. What’s the point of this? This is where you’re gonna get that edge. And there’s gonna be some tags that happen, where some of the tears start to run a little bit. But you want to go all the way around, with moderate pressure, in order to get a 360. Then you stain it, and you can see where your tear was, okay? And you go and you remove these tags. These are not connected to anything. And you use an instrument like a Sinskey hook. This is the Moria microdissector, and you’re starting to lift that edge. This is the most tedious part, but also the most fun, because what you’re trying to do is get that edge lifted without causing a tear. And you have to go 360 degrees around. You can’t skip any areas here. And the idea is to get an edge lifted all the way around. I’m gonna let you see this a little bit. And now when eye banks put S stamps on it, they put a hinge in the lateral aspect of the graft. But when I’m demonstrating here — since I learned before we used to have S stamps — is we peel until the central 3 millimeters. So now that edge is 360 free, and now we’re pulling it to the middle, and you want to pull it to the middle in all four directions. Here you can see… It’s been pulled to the middle in all four directions, and then you lay it back down and you do the trephination. You don’t want to do the full thickness trephination, because you lose the edge. You just want to tap the trephine, using a nice new sharp one, and restain so you can see the edge of your graft, and now you can see that it was cut nicely. And then the proof that it was cut 360 is you pull off this little ring, of that edge of tissue that you had prepared. So what you have here is an 8-millimeter DMEK that’s attached only there in the central 2 millimeters of the cornea. So that’s the technique that I use. Now it’s been prepared for me, I don’t have to do that, but you still need to know it, and honestly, in most countries, you’re gonna have to be preparing the donor yourself. I’ve visited doctors in India who can do it way faster than I can. They can do it in ten minutes. There’s different techniques. This is just the one I use. There are different instruments for that. The two that I use are this Y hook, and the microdissector by Moria. And then if you want to put an S stamp on it, you can find videos about it on the web about how to use a derm punch, and then put the S stamp on the stromal side. The instrumentation during the surgery itself is basically a cataract tray, and you need this guy, which is the reverse Sinskey hook. I like to use a cohesive viscoelastic. Like Healon. Not a dispersive viscoelastic. I also use this, which is a handheld slit lamp. This helps me to confirm orientation of the graft. Now, there’s many tricks for this. So you can learn other ways. But oftentimes, even if you use the S stamp, it gets distorted, and if you don’t know how to determine the graft orientation, except for the S stamp, you’re kind of in trouble. So you always need a backup. What I use is this handheld slit lamp. So I’ll show you some pictures of that. In the OR setup, you have of course the patients draped, but then on a back table, you have the stuff that you need to load the donor. You need some vision blue, you need a teflon block, and a petri dish filled with BSS solution. And then to load the donor, what I’ve evolved to now is using this Geuder glass cannula, that you can see in the bottom picture, where you suck it into the neck of the cannula with one syringe and attach another syringe on the back. For this, you need the Geuder glass cannula. You can use a 2.4 or smaller incision, and you need two syringes, as well as the tubing that comes with the glass. In the United States, this is single use, and now it comes with the graft already in it. Otherwise it would be an additional cost at the time of surgery. Now, it’s glass, and I guess you could just resterilize it. Different countries have different rules about that, but unfortunately in the US we’re kind of hand-tied in this respect. The other thing you could use is an IOL injector. This is the one I recommend, by Medicel AG. In the United States, it’s distributed by Bausch and Lomb, and it comes in two sizes. I recommend the 2.8 millimeter version. And there’s a spring present in here that you need to remove prior to loading. This is that I used to do. The other popular technique in the United States is called a Jones tube, and it’s similar to the Geuder glass cannula. Just a little bigger. So now we get to the fun part. Almost to the fun part. Regarding patient preparation, like I said, patients need an inferior peripheral iridotomy. You need to do IOL calculations, aim for -1 to -0.75. It’s good to know the white to white so you know what kind of graft size you want, and again, I recommend peri or retrobulbar anesthesia. In terms of the surgical steps, first I like to place traction sutures, which is a little unusual. Most DMEK surgeons don’t do that. Then you mark the cornea. You make the paracenteses, and we’ll go through this. The traction sutures — what do you do these for? I use a 6-0 silk for a tapered needle, and it’s good to have that tapered needle or a spatula needle. You don’t want a cutting needle, because you’ll go too deep. These are episcleral bites, and the next thing is to mark the cornea. Just to center the graft at the last step. I use a blunt 8 millimeter trephine, or an optical zone marker, and we want to center it on the geometric center of the cornea. Not necessarily the pupil. I also like it a little more temporal. Excuse me, nasal. Because my paracenteses then won’t interfere. Because I sit temporally, when I do this surgery. The incisions — you want them to start and end prior to that little line I just made here. Because if not, you have this tunnel going into where this little graft is going to be sitting. This is when I used to use the IOL injector, and I like to have an AC maintainer, but nowadays I just make two paracenteses. I sit temporal, so these are 45 degrees from my temporal incision that’s gonna be right here. We’re putting some blue in the eye there, because it helps to do the rhexis for the cataract surgery, and here is just using a 2.8 millimeter keratome. The take-home point here: You’ve got your main incision here, two paracenteses, 45 degrees away, that are not so long. You want them in the plane of the iris, and you want them to stop, before you get to this edge of where your graft is gonna be. Otherwise, if you inject air into that, later in the case, you’re injecting air into the interface, and you’re gonna want to restart some steps. Here’s the next surgical step, which is removal of Descemet’s membrane. This is a combined cataract and DMEK. I’ve already removed the cataract, and the IOL is in the bag here. And the eye has cohesive viscoelastic in it. So I go around twice, and I go just outside that little area that I outlined earlier. So you’re overstripping about half a millimeter or so. The reason for that is because you want a little leeway in that graft position. You don’t want it to just sit perfect on the 8 millimeter graft onto an 8 millimeter hole. So once you’ve gone around, then you go to the distal edge, and you start peeling that Descemet’s membrane, and you want to make sure you have one big piece, and that it’s freed up on the sides here. And you can get good visualization here, because of the red reflex. One bad thing about a combo DMEK/phaco is that you never really get the pupil as far down as you would like. And that can make graft unfolding difficult. But in this case, it is beneficial, because you see Descemet’s membrane so clearly. So anyway, then you remove it from the eye. Here’s another picture with a little better visualization. And you can see how I’ve gathered it up on the sides here. Because if it’s gonna be attached anywhere, it’s normally attached wherever they had previous incisions, or where you’ve made some. And then you’re just focusing in there. You don’t want to make too aggressive movements here, because you’ll cause little gashes in the stroma that will leave tags or an irregular posterior stromal surface that can keep the graft from adhering 100%. So anyway, you guys get the idea. Try to remove it all in one piece. And it’s really fun to do this, because it feels like you’re doing something you shouldn’t be doing. So that’s half-time. Just want to make sure you guys don’t have any questions or anything. Let’s see. All right, and then we’ll get into loading the graft, and then steps of surgery. I can’t see if there are any questions. Hm, I guess there are none.
>> None at this time.
DR LEHMANN: None at this time. Sounds good. We’ll keep moving. Thanks, Lawrence. So loading the donor. Remember, the donor’s been prepped for us, or if not, this is what you’re doing, after practicing it many times in the wet lab. When would you do it, if you’re peeling it yourself? You’ve done the first part of the DMEK, and you’ve done the PI, and then you put an air bubble in the eye and make sure there’s no bleeding. That’s when you’re really good at it. In the beginning you want to do this before you do the case, in case you damage the donor and you’re unable to proceed with the surgery. But once you’re good at it, you can do the first parts of the surgery before peeling the donor. In this case, we’ve already had a donor prepared by the eye bank, and all we need to do is dye it with Trypan blue and load it into the glass cannula. So here are the steps involved. So it’s been prepped by the eye bank, and it’s only attached here in the middle. So I’m lifting it. I can be aggressive there, because I know it was only attached in the middle. I laid it back down into the scleral rim, and I’m gonna stain it with vision blue. How long to do this? Somewhere between 30 seconds and 2 minutes, most likely. I’m using two Weck-Cels to get rid of that blue dye, and we’re gonna have a nice folded up graft that’s nice and blue. You pick it up, preferably the same edge where you picked it up before, and you’re gonna transfer it into a petri dish that’s filled with BSS. There’s gonna be some glare here. I apologize. But you lay it down and it floats, and you can see how it starts to behave. It goes in its little scroll, and now you use the Geuder cannula, where you’ve attached a 5cc syringe to the narrow neck, you suck it up into the neck of the cannula, and attach the 3CC syringe to the back of the cannula, so you have an injector. And here is a surgery I did when I used to use the IOL injector. Here it’s prepped by the eye bank, and attached at the anterior 3 millimeters. I lost my grip there. This is the same technique where we lift it out. But I’m gonna fast-forward here. Okay, so… Here we’ve stained it, we’re putting it into a petri dish, but there’s a cartridge involved at this point. So I put it into the cartridge and I’m gonna push it up into the neck of that cartridge. Now I’m advancing the plunger of the cartridge. And then you’re gonna see it… That’s the graft right there. Now, we don’t want the graft to shoot out the end of the cartridge. So at this point, you have to start rotating the tip of the injector up. And being real gentle, so that fluid comes out of the end, but the graft doesn’t. And you have the graft safely loaded, once the plunger hits this point right here. And then you’re ready to inject it. And we’ll show some examples of that. Here’s one little thing that you should be doing, is culturing the donor rim. Why is this? Endothelial keratoplasty has a higher rate of fungal keratitis than PKs do, and it’s really difficult to treat, and it seems like it’s always candida. If you do a donor culture, and it turns out to be positive, you need to follow that patient very closely. You need to treat them, and possibly redo the transplant, even though it’s a nice beautiful eye that’s quiet, because of the high risk of this interface fungal keratitis, which can appear years, even, after the surgery. So fortunately this is very rare, but I think it’s a good policy to culture your donor rims. So we’ll go through the surgical steps of DMEK. First you want to inject. Then you have to put a suture through your main wound, and then you’ve got to get that graft in the right location and orientation, and then you’ve got to stick an air bubble under it, to make it stick. So that’s simplified, but that’s basically it. So we’re gonna start with all the steps here. I’ve got about 22 minutes. So here’s injection with the glass cannula. That’s through a small incision, 2.2 millimeters, and pretty straightforward. Here’s with an IOL injector. Okay? So I have an AC maintainer. And you can see how much more difficult it is to put this injector in, because it doesn’t have so much a bevel. It’s a little too flat. Then you can see the plunger pushing the graft forward, while the AC maintainer is maintaining it, then I remove the AC maintainer, and you remove the graft. I mean the injector. So either way works, but you can see it’s a little more elegant with the glass injector. There’s no doubt about it. So you’ve got the graft in the eye, you did the suture to close the main incision, now you need to get the graft in the correct position. You need to get it centered. You have to have it in the correct orientation, and you have to unfold it. So how do you do that? Well, many surgeons have many different ways. I’m gonna share mine. There’s basically five maneuvers you have to learn. You have to learn how to flip the graft, if the orientation is not right. You’ve got to learn to unroll it, so that it’s not scrolled. You have to be able to confirm the orientation, either with the S stamp or with the flashlight. Then you have to unfold it, get any of the peripheral folds out, and you have to center it. Now, most people you talk to center the graft before you unroll it, but I’m gonna show you why that’s not a good technique. To center it first and then unroll it requires that you’re able to manipulate the anterior chamber and flatten it, but you can’t do that in every eye. You’re gonna get some eyes where you can’t unfold the graft, because you can’t flatten the AC. So with my technique, you can do this in any type eye. I say my technique. It’s not really my technique. This was something that was first done by Frank Price ten years ago. Let’s show that again. So that’s flipping it. Okay? So again, you see the orientation here? Maybe it’s not in the correct orientation. The folds are upside down. So you inject fluid underneath the graft, and it comes around the AC, flipping this thing over. Just like that. Now to unroll it, this is where you tap the cornea. We’re trying to get it to unroll. You can either tap the cornea, and then you see the rolls expanding there, or the other thing you can do is tap the paracentesis or the main wound, causing fluid to come out of the eye, and that will unroll it slightly. Okay? So here’s an example of that. I’m filling the AC. And then here I’m tapping my incision, and you saw how it opened a little bit. Even more so. You see where I let fluid out of the eye there? It unrolled. Now we’re getting it into the orientation that we like. I call this the tricorn hat, and this is my goal when I’m unrolling it. To get it in this configuration. It doesn’t matter if it’s in the center of the cornea or in the periphery. If you have this orientation, you’ll be successful with the surgery. This hat can be upside down or right side up. That’s what you have to figure out. The way you do it without an S stamp is you use a flashlight and you shine it, and you can see there are two separate white bands that are separate. It tells you that it’s in the correct tricorn orientation. If you just see one distinct long band, it means it’s upside down. I’ll show you here. Two distinct bands like this, it’s in the correct orientation. Ignore this cannula. It was just the best picture I found. If you see one long band like this, it’s in the wrong orientation. It’s upside down. So we’ll show you again here. When you see two separate bands of light, you know you’re in the correct orientation. Okay. So once it’s in the correct orientation, this has been confirmed, I use a 30-gauge needle and 0.5CCs of air, and I go in and inject an air bubble under it, and I call that the small air. And what that does is that’s gonna help you to unfold the graft. I used a different verb here, unfold. As opposed to unroll. To me, unrolling is when you’re getting it in that tricorn hat configuration and you’re confirming orientation, and now you have to unfold it. Because there’s two kinds of folds. We’ll get into that. But here where I go underneath the graft and put the air bubble. Again, slowly. Now, look at this big pupil here. This is as small as it’s getting. What if you had to collapse the AC and put the graft here on the IOL? That’s not gonna be good for the graft. That’s why the bubble is better to unfold the graft. So we unrolled the graft already, confirmed its orientation, and I put the small air in, so I can unfold it. That’s a fold right there. That’s a fold. There’s two types of folds. One is called a rolled fold, a straight fold like this, and there’s one called a point lock fold, where it folds in the shape of a triangle, and there’s a little point in the fold there. Once you have an air bubble like this in the eye, if you push here, that will get that to unfold. But the rolled fold like this, you have to be able to push in between the fold and the bubble, so that the bubble comes up into this fold, and opens it. So we’re gonna show you some energy. Again, the point lock fold? Easy. You just tap here on the point lock. The rolled fold — you have to use a traction suture to rotate the globe so the bubble is gonna up the hill, and you tap the space between the bubble and the fold, using the bubble’s kinetic energy to unfold the graft. So here’s a rolled fold. You can see that straight fold, like I’m talking about right there. So I just deepen the chamber a little bit, and I’m gonna use the traction suture, gonna rotate the eye this way, and I use that space between the bubble and the fold, and that was an easy one to get out. Here’s a little more difficult one. Excuse me. Let me go back here. Because the fold is a little bit bigger. So I’m rotating the eye. And then I’m using the cannula. I push down. And then I release quickly and use that graft to come up and kind of release that fold. And now the graft has been decentered, and so I’m gonna have to recenter it. So I’ll show you that. All right, getting a point lock fold is even easier. You can rotate the eye and you just tap on that fold, and it opens like that. Then once you’ve had it unfolded, then you want to center the graft. And you want to rotate the globe, so that it goes down the hill. You want to use smooth, broad strokes, and the eye can’t be too firm. So here’s a video of centering it. Getting rid of that last fold. And then I rotate the eye, so that it’s going this way. And you can see just with some gentle strokes here… I get it centered in the area that I want it. Inside my blue marks. And once it’s centered in my marks, then I’m good. Then I know that graft is gonna be okay. So that’s nice and centered. Now, if you center the graft first, before you unroll it and unfold it, you have a little less control over this aspect. And the last step that you do is you fill the AC with air. So I go back in a paracentesis, I gently go back to where my other bubble was, and I enlarge it, and that gets us a full fill. Now, the eye doesn’t have to be firm, firm, firm. It just has to be moderately firm. I might have to go back and give it a little more air, but it doesn’t have to be a rock hard eye. Here’s just a little video of all the moves. We’re trying to unroll it first. Here are the tricks of flipping it and tricks of getting it to unroll. I’m trying to flip it there. Now I have a good orientation, but I want to confirm if it’s the right orientation. So I use the light. This may be hard to see in this video, but I have it the right way. So I’m gonna go under the air bubble, being careful not to damage the pupil, and I put a little air bubble underneath it. That’s the little air. But now I’ve got the folds. I’ve got to unfold it. First I deepen the chamber a little bit, because it’s too flat. All right? And these are point lock folds. So I rotate the eye so the bubble is coming up here, tap on the point lock fold there, and there you go, voila. Same thing on this side. But I’ve got to rotate the eye now. I need the bubble to help. Point lock fold, rotate the eye, touch the tip of the point right there, and it’s unfolded. Now some golf swings to get it centered, and I like that, and I’m gonna augment my original bubble. That’s two bubbles. That’s not quite as pretty, but we got it. And there we are. Those are all the steps. So I’m gonna fast-forward. We already saw the steps. I bring the patient back to the operating room, and you can see this picture here — I use a 3cc syringe filled with BSS, I go in, aspirate, put a little BSS in there, fill the AC a little bit, get a meniscus on the bubble, and suck out some of the bubble. Just to clear out the graft. And then we do patch and shield and see the patient the next morning. In terms of postop care, you see them the next day, it’s helpful to use OCT to confirm the graft position, and I see them 3 to 5 days later, because if there’s a detachment, it’s generally detached at that time. So when to rebubble? This looks like a less than 30% detachment. So it’s a shallow peripheral detachment. What I do is I would not rebubble something like this. I would just have them position more. Maybe they weren’t doing it in the correct orientation, but just get it where the bubble would be in this area. If they come back on day three, and there’s a bigger detachment, and it’s on both sides here, they would need a rebubble, so I would do that under topical anesthesia in the procedure room, and generally you can get them to stick. You need to never give up on these. If your surgery was good and solid, and you had that correct orientation, you can keep fighting to get that graft to stick. I think I’ve rebubbled 3 to 5 times in the past. To get a graft to stick. And again, anterior chamber OCT — helpful. In the clinic, I use a 30 gauge needle on a 3CC syringe and have them lay flat again and just do just like I would on the initial surgery. Don’t give up. Some findings that are not as great. Here is one where it is scrolled up on the iris. That would be a bad scenario. This is my OCT, by the way. On this patient, you just have to redo the surgery. And I would use new tissue. In terms of long-term postop care, I get the patient down to prednisolone acetate 1%, Monday, Wednesday, Friday, for life. And these eyes heal faster than DSEK. They’re seeing well in two to three weeks. We normally do the other eye about a month or so after the first one. I’m gonna skip through the complex cases, because I think we only have about 10 minutes. And then we’ll go through our ending questions again, and we’ll take any questions from the audience. Which of the following would be a contraindication to DMEK? Ahmed tube, aphakia, poor view, iris defect, or PAS? Remember, PAS is… If there’s 360, yeah, you’re right. You pretty much can’t do any kind of endothelial keratoplasty. But iris defects can be problematic. Poor views can. But there’s only one on there that’s a true contraindication. Let’s see the results of the poll here. I think that aphakia would be the winner, in my opinion. We had this one already, so I’m gonna skip that one. And then in DMEK/phaco, what should be the refractive target for a plano result? There’s a range, of course. And there’s no absolutes. But more or less we’ve got to get the gist that we’re gonna aim on what side of plano? See the result here? Yeah, so everybody got that one right. That’s good. I want to thank you for your attention, and I’m happy to take any questions that you guys have.
>> Thank you, Dr. Lehmann. You can go ahead and stop your share and bring up Q and A. There are two questions so far.
DR LEHMANN: Okay, so I’ll go to the questions. Anonymous attendee. What is the meaning of DSEK and DMEK? So DSEK stands for Descemet’s stripping and endothelial keratoplasty. That’s the original surgeon. DMEK would be Descemet’s membrane endothelial keratoplasty. Basically DMEK is just replacing the endothelium, and DSEK is replacing stroma also, by a microkeratome or manually. Can we do DMEK in ICE syndrome? Any special precautions we have to take? You can. It doesn’t mean they won’t have problems with the glaucoma aspect. But you can. I haven’t done DMEK in an ICE syndrome, but it can be done. I also would take into account the iris issues. Keeping the bubble happy and everything like that. DMEK and ICE — depends on the severity of the case. In summary, yes. It can be done. But it depends on the case. If there’s very little iris, and they have bad glaucoma, I would fix the glaucoma first, I would do the cataract surgery part first, and then possibly come in with the DSEK, if the view is bad. It all depends on those complex anterior chamber questions that I raised. Okay, the next question is: By OnePlus6. Donor preparation by different technique can affect outcome? Yes, obviously you’ve got to be gentle. The donor preparation is as difficult as the surgery, but it’s something you can practice in a wet lab and get very efficient at. I think putting an S stamp on it does damage, obviously, where you’re putting the S stamp, but you still can have success with that. It’s just like anything. Once you develop your technique and you become efficient at it, you’re gonna have good results. The tissue I get from the eye bank is all good. I haven’t had a primary graft failure in the last two years or so. But often you can see if the preparation was traumatic, with the stain, if you put stain on that, and you see the dropout of endothelial cells, you know that it was a rough preparation. So you’ll learn that as you play with it in the wet lab. Dr. Singh asks: When the graft is introduced, is the scroll with endothelium on the concave or the convex side? Oh, sorry. So the graft is always on the outside. It always scrolls out. Okay? So depending on the configuration, when it comes into the eye, you’ve got to remember it’s scrolled like this all the time. So the endothelium is on the outside, okay? That’s the difficulty in the surgery. So that’s what you have to fix, by using bursts of BSS, to get it in the correct orientation. Now, a lot of doctors really fixate on how it’s gonna be introduced into the eye, and try to get it in a double scroll configuration. But it’s difficult. And it can make the surgery shorter, but you still have to be able to manipulate the graft, because it doesn’t always end up that way. All right, and then Dr. Manda asks: Would you just explain again why aphakia is a contraindication? Well, you can’t get the graft in safely in DMEK. A DSEK you can put a safety suture through, and bring it in the eye, under a glide or something, and suture it, but if you put a DMEK in an aphakic eye, where is it gonna go? It’s gonna fall back onto the retina. That’s why in my opinion — why it’s contraindicated. If you put an IOL in or you have some sort of scaffolding, that would be a possibility. But for me, I think DSEK is a safer surgery to do in aphakia than DMEK. Also aphakic eyes, generally speaking, if they have in iris, they’ve got some problem with them that is gonna decrease their best corrected acuity, and you may not get the benefit of better vision after DMEK. Next question: How much is the best corrected acuity we can achieve after DMEK and DSEK? DMEK, 20/20. DSEK, probably 20/25, 20/30. It’s also the speed at which you get it. DMEKs are fast. DSEKs take a while. In a patient with two glaucoma tubes, already had a DMEK, what do you prefer? Re-DMEK or taking out the glaucoma drainage tubes? Those tubes have to be trimmed. If they’re sticking into the anterior chamber and they’re anywhere near the graft, they’re gonna cause the graft to fail. That’s why DSEK is sometimes harder in these cases. You can get retrocorneal membrane and stuff, from the graft hitting the — if the tube is on the angle and then hitting the graft. But the tubes may not have to be removed. But they would have to be trimmed. If there’s two tubes, do you know which one is working? Which one is not working? You can remove the one that’s not working and trim the one that’s working. That’s what I would recommend. And Dr. Pandya asks again: If a graft got flipped unknowingly, can we change it after the first postop day or immediately? If the graft is flipped, it’s done. You’re killing it. If you put the air bubble on and stick it with the endothelial side onto the posterior stroma, the patient is gonna have severe edema on postop day one, and the graft is gonna be dead. Flipping it in the clinic the next day is not gonna do anything to fix that problem. The surgery has to be repeated. With new tissue. And then last question I have here is: When operating on a PBK, do you strip off the endothelium? Absolutely. Yeah, I think you do. You’ll find that that endothelium is bad. It’s opacified. And in this case, you can stain it with vision blue. Vision blue won’t stain endothelium normally, but it will if it’s all damaged, like it is with PBK. In this case, it’s very helpful to stain the endothelium with vision blue or Trypan blue prior to removing it. Also you’ll find a retrocorneal membrane sometimes, adhesions to the angle, so in PBK, especially if the eye is really bad, you definitely wanted to remove the endothelium. All right. Looks like we’ve got them all answered. So I appreciate your time. Looks like we have to be finishing now. So thank you for your time. And if any of you have any questions, you can always contact me by email. That was the last shot there. But it’s [email protected]. I’m happy to answer any questions, and I’m happy to talk with you guys independently. So thanks again for your attention.