Lecture: How to Get Started with Descemet Membrane Endothelial Keratoplasty (DMEK)

Learning DMEK can be a daunting prospect for a solo cornea surgeon, but the learning curve doesn’t have to be so steep! This live webinar is an overview of DMEK surgery, from donor selection and preparation, through the intraoperative steps, to post operative management.

Lecturer: Dr. James Lehmann, former Orbis staff ophthalmologist (2005) and currently a cornea surgeon at Focal Point Vision in San Antonio, Texas, USA.


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DR LEHMANN: Very good. So good morning, everybody. I hope you can hear me. It sounds good. My name is Dr. James Lehmann, and today I’m gonna be talking about DMEK. The target of this talk would be cornea specialists all over the world. And the main goal of the talk is just to have you get over that initial fear of starting with DMEK. Because you go to meetings, and you can kind of hear about DMEK, and you hear how daunting it is. It’s 8:00 am in the morning, here in San Antonio, Texas. So good morning to everybody. How about buenos dias. Bonjour. My name is James Lehmann. I’m a cornea specialist in private practice here in San Antonio. I do about 60 corneal grafts a year. And now I’m about 80% DMEK. No relevant financial disclosures for this talk. I’ve had the privilege to work with Orbis for many years, first with the flying hospital, and then with different programs. This is a picture from Jerusalem, India, and Jamaica, over the last few years, to help teach DMEK, DSEK, and PK in other countries. So this is a little overview of the talk. You can see from the picture how clear and pretty this cornea is. And this is the goal. DMEK is the best rehabilitation for a defective corneal endothelium. And your corneas will look like they never had any surgery done to them. We’ll be going through each of these topics, from background, instrumentation, through the steps of the surgery itself. So here are the first preliminary questions, just so I have an idea about the audience. And Lawrence will pull up these slides. But how many DMEKs have you performed? And we can get a tally there. None, okay. So most people haven’t performed any. And then about one out of five have just begun. So pretty much a novice DMEK audience. That’s fine. Question two: I have easy access to prepared/stamped DMEK tissue. This is gonna help me to know about: Do you have to prepare the tissue yourself? Or it can come from an eye bank? I’ll get the results there. So that’s what I thought. Most places outside of the US, Canada, and Europe wouldn’t have access to prepared/stamped tissue. Here’s another question. Which of the following is a contraindication to DMEK? Having a tube in the anterior chamber, being aphakic, having a poor view, an iris defect, or peripheral anterior synechiae? And we’ll get the results there. Okay, so kind of all over the board on this one. We’ll go into this in the talk. Some of these are relative contraindications that can be overcome with experience. But I would say aphakia would be the strongest contraindication. Another question, just to test your knowledge about corneal preservation. A cornea preserved in Optisol can be preserved for five days, 10 days, 14 days, or 18 days? This is relevant when you receive a cornea from the US and you have a limited time to place it. So everybody seems to be on board with that. And if you’re doing a combination of a DMEK and a phaco, what would be the refractive target for Plano result? What do you shoot for so that you get zero? Spherical equivalent, of course. And we’ll get the results there. Around -1 to Plano. So that’s good. As we know, there’s a mild hyperopic shift with any endothelial keratoplasty. So let’s talk about background of corneal transplantation. This is a photo from a patient of mine who had an original square graft done in the ’60s. This cornea was from a 60-year-old back then, so it was over 100 years old at this point. Back then, they had steel sutures and special knives that could cut only in this square pattern. And it was a one size fits all, for a long time, essentially since the last 20 years. So in the history of endothelial keratoplasty, we were shown that you could use an air bubble to stick onto a recipient cornea. And then in 1999, Dr. Terry but good result that involved perforation of the extra stroma, which was very difficult, and it wasn’t until 2004, where we used a microkeratome to prepare the DSEK donor, and that was the gold standard, until Dr. Melles showed us you could do the same thing without the posterior stroma, to do the DMEK. Until 2012, not many people were doing DMEK across the world. There were problems with preparation, et cetera. So the beauty of DMEK is precise anatomical replacement. You can see a clear, thin, compact stroma. And this is a patient, postop day one, that I did last week, and this is a patient with an Ahmed tube that I trimmed here. You can’t get these results with DSEK. You have less refractive shift. What are the downsides? Learning curve. And you have to have a somewhat normal anterior anatomy, can’t have an anterior chamber lens, and you have to have a good view for surgery. So here’s a chart showing just what’s happened in the US over the last decade. You can see in 2011 endothelial keratoplasty surpassed penetrating keratoplasty as the predominant corneal procedure done in the US. We do about 40,000 to 50,000 grafts a year, and now the majority of those are done by endothelial keratoplasty. So this includes DMEK and DSEK. And then this next slide shows you the change. Since 2012, only about 3% of endothelial keratoplasties were DMEK in the US, and last year it was 23%. I would say it’s closer to 30% now. I just don’t have the latest data, but you can see that huge increase. So many more surgeons in the US are doing DMEK, and it’s mostly due to preparation of the donor at the eye bank. This is the number per month. Before 2012, it was 100 a month, and now we’re about 500 to 600 a month. So donor selection. Here in the US, when you request a cornea, you receive a PDF or a fax with information about the donor tissue. Where it’s from, characteristics about the donor, how they died, and then specs on the tissue. So you read these things and you choose your cornea. The donor cornea selection in DMEK is slightly different than with DSEK and penetrating keratoplasty. You kind of want older corneas, because they’re easier to manipulate during surgery. And the other characteristics — cell count, preservation time, days to surgery — all those are very similar. We’ll go into a few differences here. Just to reference some landmark studies done in the US over the last 20 years. The cornea donor study by Dr. Holland and others showed that donor age was not very significant until you got to much older tissue. Cornea surgeons always wanted younger tissue, and this study showed that there was not a significant difference in the outcome, unless you were really in the upper ages there, with 70-plus. The corneal preservation time study which was just published this last fall compared DSEK tissue that had been preserved from 0 to 7 days and 8 to 14 days. And all of them did well. But the 12 to 14 day corneas were still good, but slightly worse. This is relevant in DMEK, because we want older corneas. I use corneas from 45 to 65. This allows you to harvest it easier, it’s not as adherent to the underlying posterior stroma, and you’re able to unroll it better in the eye. So there has been a trend in not using diabetic corneas, because of problems harvesting. These tears that you can get, when preparing the cornea. So more studies are showing that there is an increased risk of harvesting from diabetics. But on the other hand, there are many more diabetics in the population. So we haven’t figured out a good middle ground on that. I still take diabetics. We don’t want pseudophakic patients, because harvesting it is difficult with previous incisions. And so, when we have a patient with endothelial dysfunction, and we want to decide what kind of surgery they need, we talk about preoperative planning. The first thing you have to talk about with surgery is you have to think: What kind of anesthesia am I gonna use? Is the patient able to cooperate and position if needed? Because of this air bubble problem? What does the anterior segment look like? Is the patient phakic, pseudophakic, aphakic? Should I do DSEK or DMEK? So the anesthesia I use for DMEK would be peribulbar anesthesia. And what the goal would be is if the patient is comfortable and the eye is controllable. That it’s not moving. Additionally, the patient has to be able to lay flat the night of the surgery, so that the air bubble points up and sticks the endothelium to the new recipient. Also, the patient has to be cooperative. Because sometimes you have to rebubble, and we do that in the office under topical anesthesia. And so the patient… I think in many countries, especially those I’ve visited, it’s better to take a patient back to the theater, if this is the case. But if you’re gonna be doing this in private practice or in a setting where you don’t have ready access to a theater at all times, the patient has to be, as we would say, with it enough to undergo a rebubble under topical anesthesia in the office. Who’s the best candidate for DMEK? It would be somebody with Fuch’s dystrophy, or mild pseudophakic bullous. An ACIOL makes it extremely difficult to unfold the graft. I could say that’s definitely a contraindication, and would move to DSEK in that scenario. Iris damage — the more synechiae, iridotomies, the more missing iris tissue, the more difficult the case. Additionally, minimal stromal scarring. You don’t want to do endothelial keratoplasty in somebody who is gonna have 20/70 vision because of the scarred cornea. This can be difficult to assess, and it takes some experience and multiple cases to know how much stromal scarring is prohibitive. Also, you want to make sure that if they have a PCIOL that you’ve dilated the patient and it’s stable. You want to make sure it’s not dangling or there’s a big rent in it, because the surgery could dislodge the lens. You want a good view, Fuch’s dystrophy, pseudophakic, no ACIOL, no iris damage, and a stable PCIOL. So this is a patient with corneal edema and Fuch’s dystrophy. This would be an ideal candidate. These, not so ideal. These would be amenable to DSEK or PK. Here is too much stromal scarring. Even if you did successful DMEK or DSEK, they would still have poor vision. And this last case, not much to work with there. People can do DSAE in these eyes if they’ve been nicely vitrectomized, but you have to look at the visual potential as well. ACIOL would be a contraindication to DMEK, in my opinion. DSEK you can do with an ACIOL, but if it’s in there and causing inflammation and corneal edema, it may be worth doing a two-step procedure and suturing one to the sclera, or doing the new intrascleral haptic fixation technique. So in my hands… This case with a PCIOL that’s in the AC here, I would do a two-step procedure in which I remove this lens, suture a lens to the sclera, and then came back and did a DSEK. In terms of lens management, if you’re gonna do contract surgery at the same time as the DMEK, you have to be a good cataract surgeon, because the view is always quite poor through these corneas, and it oftentimes is the hardest part of the case. The DMEK, you’re kind of relaxed and breathing happily. And it’s during the phaco part that’s difficult. There’s a hyperopic shift with DSEK and DMEK. I aim for 0.5 to -1. I hesitate to put in a multifocal IOL, because as the cornea deturgesces in the weeks after the keratoplasty, oftentimes the astigmatism can change, and I’ve seen patients have a big shift in their astigmatism from what we measured preoperatively. I would hesitate to put in a toric lens. There are surgeons who do it. If you’re just thinking about debulking the astigmatism, in a sense, you can do that, but oftentimes, I think it’s safer just to stick with a standard monofocal IOL. The question that pops into my mind often is: Do I do DMEK or DSEK on this patient? This is an anterior chamber after DSEK. You can see this posterior lenticule here. I think both are very good surgeons. And as a cornea surgeon today, you need to be able to do both of them. But I’m more and more doing DMEK in eyes that perhaps I would only have done DSEK in the past. Things like tube shunts or iris defects. There’s better vision, faster recovery, and less refractive shift with DMEK. And I think overall it’s a good surgery. The only real contraindication I have is if there’s an ACIOL. Then I always go with DSEK. If you have a failed PK, I’ve been doing DSEK on these, but there are many presentations at the meetings about doing DMEK with these. The issue with doing DMEK under PK is it’s difficult to strip the endothelium underneath it, because you can disrupt the graft-tissue interface here, and it’s hard to peel. So I still do DSEK on these eyes, or PK, depending on what their best corrected vision was, if they had successful vision in contacts or glasses. But that’s a lecture for another time. More about penetrating keratoplasty. So we’ll continue here. Again, these are eyes, glaucoma surgery with pseudophakic bullous. I see this more than anything. Cataract surgery doesn’t cause pseudophakic bullous anymore. It’s mostly with glaucoma surgery, so in these eyes, I’ve been doing DMEK, and having good success, like that picture I showed on the second slide. Again, you need to have experience. These wouldn’t be the first cases that you did. But they do great. So in a summary of preoperative planning, kind of the checklist you would run down: The anesthesia, I suggest peribulbar anesthesia. The patient needs to be cooperative enough to lie flat during the surgery, the night after the surgery, and to possibly undergo rebubble in the office if needed. I think the best cases are Fuch’s dystrophy or mild pseudophakic bullous. So when I travel to places like South America or India, of course, there’s pseudophakic bullous there as anywhere, oftentimes after complicated cataract surgery. And the patients we see are two or three years after the complicated cataract surgery. By then, it’s really hard to do these surgeries. It’s almost better, once you have access to tissue, and you become comfortable prepping the tissue, to wait three months after the complicated cataract surgery to fix the cornea, instead of many years, because it sometimes would preclude DMEK, and you would end up doing a PK or DSEK. So again, the easiest candidates are mild pseudophakic bullous, those with Fuch’s dystrophy. In every country in the world, there’s Fuch’s dystrophy. And I would at first avoid eyes with anterior segment pathology. Additionally, if the view is good enough, I would do peripheral iridotomy in the clinic. But oftentimes in developing countries, the corneas are so edematous you have to do it at the time of surgery. So a good trick is to use a vitrector, without inflow. So tissue prep. In the US, when people first started doing DSEK, each hospital would have to buy a $35,000 microkeratome, and the surgeon would prepare the DSEK before the case. That would be cost prohibitive in many locations. It takes time, money, and if you damage the cornea, you’re still out the money that you have to pay for the cornea. The same thing with DMEK. When it was first done, the surgeon would have to harvest the DMEK, prior to the surgery. It takes, even in good hands, 15 to 30 minutes to do. And again, that’s time, money, and the risk of damage to the tissue. So now it’s evolved to the eye bank preparing the DMEK tissue, and it arrives in a viewing chamber, like this. Many eye banks now are putting that S stamp on there, to help with tissue orientation, and that’s been a big leap forward, in terms of surgeon comfort and confidence, in terms of performing DMEK surgery. So nowadays, we request the cornea. There’s an additional fee that’s charged for preparing it. And we’re even getting eye banks that prestain it and preload it. So here’s an old-fashioned way of preparing the cornea. So I’ll start slowly. But this is called a Bechert Y hook. This is done under high mag. And we’re scoring Descemet’s and endothelium, just outside the limbus. This is helping to create that initial groove. There’s many ways to prepare endothelial tissue for DMEK. And oftentimes people will start with a scraper where the scleral spur will be up here, because it’s kind of the natural start of the endothelium, and allows easier harvesting. So you’re using the red reflex and scoring all the way around, 360, at about a millimeter in from the limbus. So you still have plenty of area to punch. Then you stain it, and you can see where the scoring has happened. And then you use this device called the Microfinger. You can also use a Sinskey hook in this. If a tear is gonna happen, it happens right here. So by using this Microfinger, you tease the edge of the endothelium up, and you’re able to peel it without getting that tear. So again, you go 360 degrees with this. Now, this is gonna be the first step for many DMEK surgeons, when you get your hands on some tissue, to start harvesting it. So the next slide will show the instrumentation you need. And you can look at this in more detail. I can make this presentation available to Orbis. But once you’ve gone 360, then you start to peel the tissue towards the middle. This is all under Optisol in this viewing chamber. And we try to preserve the central 3 millimeters. Now, in this case, we’re not gonna place an S stamp. If you’re gonna do an S stamp, you peel it all the way to a hinge that you would have here at the bottom. Now you’ve transferred it to the punch. And then you use Weck-Cels to get rid of the Optisol, and that causes the DMEK tissue to lie flat. And then you do partial trephination with an 8 millimeter trephine. It has to be a new trephine. Can’t be reused, because it has to be sharp. You stain it so you can see where you cut it along the edge here, and you’re removing this little ring. That tells you that you had a good cut, because there’s no tags. Obviously if you were doing this surgery, you would do this before you had the patient receive anesthesia. Just in case there’s any problems. So I would prep this, and then block the patient and bring the patient into the OR, with this on a back table, covered. And we’ve done that before, in different countries. So the bottom line regarding tissue preparation: in the USA, it’s better to get it from an eye bank, because it’s prepped for you already. It’s less financial risk to the surgeon, less OR time, and just makes it easier overall. You can see here there’s a prestained, preloaded DMEK tissue, and that’s kind of the next generation of delivery there. All right. So we’ll talk about instrumentation. These are the instruments you just saw in that last video. One second here. So I can show you here. This is the Moria Microfinger. And these are a pair of straight tiers, the Bechert Y hook, and a pair of scissors, in case you get a tag. This is half-time on the talk. If there are any questions, I can take them at this time, on patient preparation. Surgical planning. Tissue preparation. I’m looking at my little Q and A box. I don’t see any questions. So just let me know if there are any issues, and I’ll continue. Patient and theater prep for DMEK. All right. So patient preparation. We talked about doing this inferior iridotomy. Needs to be at 6:00. And this can be done preoperatively, if there’s a good view. If not, it can be done intraoperatively. We talked about IOL calculations. It’s good to have a white to white measurement, just to make sure that the recipient is in the majority of patients, in the 11 to 12 millimeter range. In some countries, the corneal diameter is smaller, and you would make the DMEK smaller. In the US, we use 8 millimeter DMEKs, for basically 12 millimeter horizontal diameter corneas. But in India, it was 11.5, so we used 7 millimeter grafts. So you would just adapt that to your location. And in terms of anesthesia, we talked about the peribulbar anesthesia. When you’re doing the surgery, it’s essentially a cataract tray with a few extra instruments. One is the reverse Sinskey hook. Another is a blunt 8 millimeter trephine. You need a 10 cc syringe with BSS, you need a TB syringe with a 30-gauge needle, and you need a cohesive viscoelastic like Healon. Additionally, this is what I use to verify the graft orientation. It’s a handheld slit lamp made by the company Eidolon. It can be purchased online. In other countries, there may be other handheld slit lamps, or you may want to prep the graft and use an S stamp. To load the donor, we prepare a back table just like with any cornea case. You need a petri dish, you need BSS, you need a sterile viewing chamber to have the graft transferred into, and you need some Trypan blue. There’s different ways to load the DMEK. Anything from a modified Jones to this IOL injector. This is what I use. In the US, it’s distributed by Bausch and Lomb. But in different countries, it’s under different names like Medicel. It’s available in almost any country. It doesn’t have to be this device. As long as it has a cartridge that’s similar, you can find one in your country that would work. I use the 2.8 millimeter size, and I use a 3-2 incision for that, so it’s the bigger one. Additionally, there’s a spring that’s present in the middle of the injector. And I remove the spring, because you don’t need it in DMEK surgery. So again, many ways to inject the graft. The one I’m gonna show in my videos and the one I’m used to is injecting with this IOL injector. So how do you prepare the eye for surgery? All right, so we’re gonna go through the surgical steps. But they work like this: First you make some traction sutures. Many DMEK surgeons don’t use traction sutures, and I believe they make the surgery easier, because it’s easier to manipulate the graft. I’m gonna demonstrate this technique. You mark the cornea, you make the incisions, you fill with viscoelastic, you remove the endothelium, and then you remove the viscoelastic. So we’ll talk about that. This video shows placement of traction sutures. They’re about 3 millimeters posterior to the superior and inferior limbi of the cornea, and they’re gonna make it easier to unroll and unfold. This is my first step. You take an episcleral bite. The main take home point on this is you want to use a spatula or tapered needle. Anything with a triangular shape you don’t want. You can use vicryl. This is silk. Either a spatula or a tapered needle. We mark the cornea. This helps to center the donor. We mark the central 8 millimeters of the cornea. This is just a blunt trephine, marking the epithelium. And we’re gonna come by — I sped up the video here — marking the central aspect. That’s gonna help us later in the case to get the central graft. Also where we want to strip with our reverse Sinskey hook. Nothing fancy there. And the incision. This is a patient — you’re probably looking at the cornea, saying: Hey, this patient doesn’t need surgery! But there are guttata there. And the incisions are just like with cataract surgery. So you would be sitting temporally over on this right side. And those are the two paracenteses, we fill the eye with Vision Blue, we rinse it out, this helps to stain the capsule for the cataract surgery part, but it does pick up a little bit where there’s been dropout of cells on the endothelium. And this is a 2-6 keratome that we would enlarge after the cataract surgery part, so again, you’ve got two paracentesis I make them superior and inferotemporally. It just depends on how shallow the AC gets when you’re doing the injection. So those are the incisions. And then the preparation of the recipient also involved stripping the Descemet’s membrane. So this is a different orientation here. The surgeon is sitting temporally, but the video is kind of 90-degree rotated. You’re going in here with a reverse Sinskey hook. So this is familiar to anybody who is already doing DSEK surgery, because we have to remove Descemet’s in that surgery. So I go just outside the central 8 millimeters, to about 8.5, 8.75. And I like to go around twice. With a moderate amount of pressure. You want to see a little bit of whitening. Not too much, because then you’re just tearing up posterior stroma. And you go to the distal aspect of the anterior chamber, and you start raking the Descemet’s into the middle. You don’t need any other instrument, other than a reverse Sinskey hook. And the red reflex from the somewhat dilated pupil is helpful to see what you’re doing. You want to try to minimize any tears or tags out here. But more importantly, you just don’t want to be so rough that you damage the posterior stroma. Because that can cause an irregular surface that makes it harder for the DMEK graft to adhere. So we’ve got all the Descemet’s, and we just remove it from the eye. Here’s another case that’s already kind of part of the way through. Just has nice visualization of the edge of Descemet’s there. And we’re just kind of bringing it to the middle here, making sure it’s been harvested nicely all around the sides there, and then you’re just gonna pull it out of the… Pull it across the center with moderate pressure there. And it tends to want to come all by itself. All in one piece. It’s not very difficult, this part of the surgery. And you kind of get the idea here. This one is being a little more stubborn. But if you grab centrally, it’s all gonna want to come in. There we go. Just very patiently, with a nice moderate amount of pressure. Get it out of the eye there. All right, so… Next step: It involves loading the donor cornea. So like I said, when I request tissue, it arrives like this, in a… Minimize my screen really quick. There we go. All right. So I receive tissue like this, in a viewing chamber. But this viewing chamber is not sterile. So I just got a question: Do you dilate the pupil to see the red reflex? That’s from that last slide. In a combined case, the pupil is somewhat dilated from the cataract part of the surgery. I use that, and then I will place Miochol in, after removing the viscoelastic, to perform the DMEK part. But if it’s a DMEK alone, no, I don’t use any dilation. In fact, we want the pupil small. In a pseudophakic bullous, the Descemet’s membrane and endothelium — because it’s been damaged so much, it stains very nicely with Vision Blue, and that’s all you need to do. In a Fuch’s patient, that’s not the case, but you can have good visualization to do the Descemetsorhexis. So moving along here with donor cornea loading. Again, I receive it from the eye bank like this. Already trephinated at 8 millimeters, with the S stamp. Which you don’t need, but it’s nice to do. So we’ll take it out of this, stain it with Trypan blue, and load it into the injector. I do all of this under the microscope. It’s only attached in that central 3 millimeters. It would be tough to ruin it at this point, but you could still tear it. That’s just some heme and debris there. I like this video, because you can see… When I let go there, kind of that it’s only attached there. That’s where the resistance started. We pick up the Descemet’s membrane, and I take the scleral rim and we transfer it to another piece of the table, and now we’re getting all the Optisol off. You have to use two Weck-Cels here, because if you just use one, the graft will run with that capillary action. We’re putting the Trypan blue in here. Different surgeons will leave this cooking for different times. I’ve seen this up to 3 minutes. It used to be thought that the longer you had it it was toxic to the epithelium, but studies have shown that’s not necessarily the case. I do it for 30 seconds, but I think somewhere around a minute is probably the best. And we transfer it in a petri dish with BSS into the cartridge. A little bit of glare here, but I have some other videos you can see. And you tap it into the barrel of the cartridge here. So this is all underneath BSS. And now you can see me advancing the cartridge. So that’s the plunger. Getting the back of the cartridge. And then now you have to be careful not to eject the DMEK. So you have to tilt the tip of the injector up, so that the water — BSS — falls out of the tip of the injector. And I’m doing this under the scope. Until you get engagement of the plunger into this last part of the cartridge. And then you know it’s a pretty stable entity here. And you can go ahead and transfer to the other… You can move the microscope back, and begin to inject the graft. So basically now we’re at the steps of the surgery. Again, I lost my little pointer. I’m gonna come back right here. All right, so… So this is where there is a lot of difference in terms of doing surgery. But I’ve tried to simplify it in a way where we break it up into three parts. So you have to inject the graft, there’s different ways to do that, you have to do the dance, as I call it, to get the graft in the correct orientation, which then needs to be confirmed, and then you need to put a big bubble of air underneath it, to stick it to the posterior stroma. Injection can happen in many ways. But I’m just showing you here the way that I do it. This eye had a pretty good chamber, so I didn’t need to use an AC maintainer. And I got the tip of the injector inside the eye. You have to be completely in the eye. It can’t just be like phaco, where it’s wound-assisted. And that’s achieved by a consistent pressure with rotation. Stabilization of the chamber here. I’m putting a little BSS into the chamber, so that it deepens a little. Conversely, you can use an AC maintainer. And then you inject the graft. Now, you have to be careful when you withdraw the injector that the graft doesn’t come with it. So sometimes you do what’s called dumping the AC of any fluid. This AC is already pretty empty. And you can see when you remove it nothing wants to come with it. So that’s an injection. Again, there’s many ways. There’s the modified Jones tube. There’s the Geuder glass. And there’s different ways to do it. They all achieve the same goal, which is injecting the graft into the anterior chamber. And then you have to suture the incision after that. I think you find just what you’re comfortable with, and attending a DMEK wet lab and playing with the different injectors is a good way of doing that. So here’s injection. Here’s another case I’ve done recently. This is in a glaucoma tube patient. The tube is up here. I had to use an anterior chamber maintainer to keep the chamber deep. You can see a little bit of iris prolapse. Consistent pressure, putting the injector into the eye and injecting the donor off to the side here. I don’t want this thing running, so I pull it out of the eye and then withdraw the tip of the injector. That’s another way of doing it. I’ll show that again. This is the latest case I did I think last week. The view was poor, so I had to debride the epithelium. Again, consistent pressure, rotation, to get the bevel through the incision. Injection of the graft into the anterior chamber. With removal of the anterior chamber maintainer. And then removal of the tip. Now, in this case, I injected the graft a little bit off-axis, so that it wasn’t just sitting right by the incision, wanting to come out. This makes it a little bit harder for it to come out. And you can see the chamber is quite flat here, through the stria and the cornea. So that’s injection. The next part, after you suture the wound, it’s the dance. And the dance has different moves. But there’s four essential moves, in my opinion. Sorry, I’m losing my little pointer. There we go. We’ll do that again here. All right. You have to be able to flip the graft, in case you have it upside down. You have to be able to unroll the graft. You have to be able to unfold the graft. And you have to be able to center the graft. Different surgeons do these steps in different orders. Some surgeons center the graft first, and then unfold it or unroll it. I feel like unrolling it is the best thing, and then centering it. And that’s where the traction sutures come in helpful. So I’ll show you my technique, but again, there’s different ways of doing this. All right, so the first step: Flipping the graft. So you’ve got the graft in the eye. You have a suture through the main wound. And now you use your paracentesis and use your syringe with BSS. That’s the flip. That’s all there is to it. You go under the graft and inject into the anterior chamber. It makes a wave that comes back and flips the graft. If you’ve got it in the wrong direction and you have to flip it, that’s what you do. This can be performed in the first step, if you can verify the orientation with the S stamp, or it can be done once you unrolled it a little bit. Unrolling the graft. This is different from unfolding. Unrolling means you’re trying to get it in an orientation in which you can verify the position, whether using a slit lamp or an S stamp. Different people do it different ways, but there’s three key components. You can tap the cornea with the AC flat, or you can release fluid through one of the paracentesis, which causes the chamber to shallow and the graft to unroll a little bit. So you either tap it or release fluid. By manipulating the depth of the anterior chamber, making it shallower, you unroll the graft. By making it deeper, injecting fluid, the graft will start rolling up again, which is helpful if you need to verify orientation using the handheld slit lamp, but not helpful for unrolling the graft. This is a shallow chamber, the graft just after injection, and I’m using a tap technique to unroll it. Now I’m thinking… That’s easy. The surgery is already done. But you have to verify the orientation. This could be upside down. If you have an S stamp, it may tell you already that it’s upside down. Again, here’s a different technique. So we have the graft. And we need to unroll it. I’m gonna use BSS — did you see that? I just shallowed the chamber through the main wound, causing this to unroll slightly. And now I’m tapping this incision here, so that it can come out. So now I have it in this orientation, called the tricorn hat orientation. This is what you use when you need to verify the position. Again, I’m gonna show this video. So instead of tapping it, I released fluid from the AC, and get it to unroll on its own. Now a little bit of tapping, a little bit of tapping, and I go to this paracentesis. I release some fluid, and that allows it to open. So again, you can tap or you can release fluid. And we want to get this orientation. The question is: Is the graft like this? Or is it the hat upside down? If the hat is upside down, you need to flip it. So this is what I use with the handheld slit lamp. The tricorn hat can be… It can have orientation in the correct way, or it can be upside down. Now, I don’t use the S stamp, because when I learned to do DMEK, there was no S stamp. And what I do is, at this step, we turn the lights off in the OR, and then I use a slit lamp beam. You can see here that it creates a light beam on top of the graft — that you can see these two rolls. If you see one broad beam, that means it’s upside down. But if you see these two beams separated by a black space, it means you’re in the correct orientation. I want to show that again, just to kind of hammer that point home. You turn off the lights. You get this handheld slit lamp, and I’m running the beam over the graft, and I’m seeing two distinct lines here. That tells me the graft is in the correct orientation, and these rolls are showing me it’s in the correct tricorn hat configuration. So this obviates the S stamp. Which is a good technique too, but I feel like it’s unnecessary. So I’m showing you the video… Sorry, I keep using the pointer. So different tricorn hat configurations. You see here on the side that the… Oh, sorry. I keep losing the pointer. I don’t know why. It doesn’t like it. All right. So you look with these two different orientations. When the light beam goes over it, and you see two distinct beams, that means you’re seeing these things. That means you’re in the correct orientation. If you see one distinct beam like this, it means it’s upside down. We already talked about that. And the next step, after you confirm the orientation, is to inject what I call “small air”. This is a small air bubble that helps you to unfold the graft. Not to unroll it. It’s already been somewhat unrolled. But to unfold it. This is a 30-gauge needle, with only about 0.3 of air going in the eye right here. It’s a TB syringe, and it’s got to be a good syringe with good action. And you put a bubble underneath the graft. And this is gonna help you to unfold the graft. Okay? So this differs from people who center the graft first. And then just unroll it. This works if the graft is decentered. Because you’re able to manipulate the eye easily with the small air. So here’s our picture of the graft with the small air bubble under it. And we have to talk about unfolding it at this point. So there’s always two kinds of folds. This is called a point lock fold. And then this would be just a rolled fold. Okay? And so there’s two techniques to get these out. So the graft has a small air bubble underneath it, but it’s not completely unfolded. All right? So this is where you use the traction sutures to help manipulate the eye position, to use the bubble to your advantage. So we’ll show some videos here. This is the rolled fold. This is where the graft has this big roll in it, right here. And we’re gonna use the air bubble to unroll it. Unfold it, rather. All right. So what we do… We rotate the eye to get the bubble to come uphill. And then you create space between the bubble and the fold. And the bubble itself will come up and unfold the graft. Now we’ll show that graft is decentered. So now we’re gonna show how we get it centrally. But we see we can unroll it that way. Here’s a graft showing that point lock fold. This thing right here. Okay? So in this situation, again, we use the bubble. And we roll the eye, but you just touch the point of that fold, and it unrolls like that. So very easy. All right, so now we have to center the graft. And this is where you do what are called golf swings. So you want the eye — not too firm. And we want to rotate the eye using those traction sutures, so that it goes downhill. So here’s that same case. We have the eye rotated now away from us. So that you can golf swing it into the center. So you see how easily you’re able to manipulate that graft with an air bubble, with those traction sutures. Because you get the graft to go downhill. So if you use the technique in which you center the graft first, and then you unroll it, or unfold it, and then it gets out of position, you’re not able to do this. This is why this is a nice technique, of using the small air to put the air bubble underneath it, and then you can use these traction sutures to manipulate it. Again, I’ve seen many surgeons struggle with centering the graft. And this allows us to do that easily. So here’s a fold. Here’s a decentered graft. But we’re able to get this graft where it needs to be. So we rotate the eye so that the bubble is gonna come uphill. And we’re gonna create space between the bubble and the edge. And use its energy to come up and unroll it. All right. So now it comes nicely. So now it’s been unfolded. But look how offcenter it is. If you don’t have an air bubble in here, there’s no way that you’re gonna be able to get that graft centered. So now we rotate the eye so that the graft is going downhill. We rotate the eye away from us, and we use this golf swing to get it centered. I’ll show a little bit more of this video. And I know we are kind of running a little low on time now. About 13 minutes left. So I’m gonna speed things along here. But you use golf swings to rotate it. As long as you keep the air bubble underneath the center of the graft, and there’s a little fold, but that’s okay. We can just tap at it, and it will be okay. As long as you keep the bubble in the center of the graft, you’re able to golf swing that to center it. And so this is a nice technique. It works in deeper chambers. You can still center and manipulate the graft. Whereas with the technique about centering it first, and then unrolling it, it only works if you can shallow the chamber. So again, we get a nice centration here. All right, so after you’ve centered it, then you want to fill the eye with air. So you go back to your small bubble, and you fill the eye. Now, you don’t have to fill it so firm like a DSEK, where the pressure is 40. But you want it firm, but not too firm. Then the patient goes to the postoperative area and they lay flat for 45 minutes. That’s kind of the next step. And then we go back to the operating theater, and I use 3CC syringe with a 30-gauge needle, and we remove enough air to clear the inferior iridotomy, and I put a bandage lens if needed. Then we patch the eye and we see them the next morning. They lay flat all night. This is an edited full DMEK surgery, which is one of my second to last slides. So we’ll show this. I’ll kind of move along through the cataract part, because this isn’t really the topic we want for this talk. But you can see — just kind of standard cataract surgery. Get the lens in. Now we’re doing some stripping of the endothelium. I’m moving things along. Now I remove the viscoelastic. Now we’re gonna inject Miochol to get that pupil to come down. We’re prepping the donor here. So staining it. Now we’re gonna load it up into the cartridge. And you can see this. This one is a little better video. It doesn’t have so much glare. We’ve got the cartridge submerged under BSS here. This of course can all be practiced in a wet lab, so you can do a good job, when it comes time to do the surgery. Sometimes it doesn’t scroll up quite as much. And it doesn’t want to go into the injector. So you just have to sometimes manipulate the fluid around it a little bit, and get it to shrink up. And then you can get the edge into the cartridge like that. And now… We’re gonna inject it. This eye didn’t need an AC maintainer. The chamber stayed deep enough. Injecting it off-axis here. And then we’re gonna dump any fluid in the anterior chamber, and then remove the device. There we’re unrolling it. Checking to see if it’s in the correct orientation. So we turn the lights off. This isn’t a very good video to see here, but it’s upside down. So then we need to flip it. Like that. And now we’re in the right orientation. A little air. Got that point lock fold right here. We need to knock out that point lock fold. That’s the next step. So we’re gonna deepen the chamber a little bit, so that we can manipulate the graft. And then make the bubble go uphill. Touch the point lock fold. Get it to unroll. And you get the idea. Small air and then big air. All right, so postoperative care. This is pretty straightforward. We see the patient the day after surgery, and then about three days afterwards. It’s helpful to have the anterior chamber OCT to confirm the graft position. I wouldn’t say it’s totally necessary, but if the cornea is edematous, you can’t really see the orientation. The graft is too thin. So I think most hospitals that I’ve visited now have these anterior chamber OCTs, and I think it’s a helpful device. So talking about rebubbling — let me go back to this slide. Oftentimes you’ll see the peripheral detachment here. If it’s less than 30% on postop day one or three, and they still have a bubble, you can get them to position more. Most of the time, this is inferior, and they didn’t lay flat the night before, but if you just see a shallow peripheral detachment like this, you don’t have to rebubble it. If most of the graft is detached like this, then you do need to rebubble. And so the rebubbling, it’s like the last step of the DMEK. I put a full air bubble in, let them lay flat for 45 minutes, and remove it, and then position it again just like the surgery. And oftentimes we can get it to stick again. We talked about rebubbling. If you need to rebubble, and there’s no air in the anterior chamber, it can be difficult, because you can dislodge the graft. So you have to have good visualization, and you have to be very careful. I also say don’t give up. I’ve had grafts that I’ve had to rebubble two, three times. And I can get them to stick. So as long as you know the original surgery was not traumatic, and that there were no shenanigans at the eye bank, preparing the tissue, you can be very successful with rebubbling. Some other OCT findings, if you look in the bottom right there, that’s one scrolled up, resting on the iris. That would be one that you would have to raise the white flag and just redo the surgery with new tissue. But the other two, I’ve had these scenarios, it but the other two, I’ve had these scenarios, and been able to get them to stick again. Long-term, the benefit of DMEK is less risk of rejection, so we’re able to get the patient down to every other day steroids for life. These patients see very well very fast, so they want the other eye done in a month or so. They don’t generally want to wait, like with PK or DSEK. So we’ll go back to the questions. These are three of the original four, and see how well everybody was listening. So Lawrence, if you can pull up the polling device: Which of the following is a contraindication to DMEK? Ahmed tube, aphakia, poor view, iris defect, or peripheral anterior synechiae? All right, good. Aphakia. All right, next slide. We already got this one right. But you can run it anyway. A cornea preserved in Optisol can be preserved for how many days? Let’s see the results. All right, 14 days. And again, the CPTS study showed us that corneas are good up to 14 days. Generally everybody had good results with DSEK. There was a slight decrease in the 12 to 14 days. And if you’re gonna do a DMEK/phaco and you want them to end up with Plano, spherical equivalent, what do you shoot for? Most of you guys had a good handle on this, even before the questions. You can show the results there. Yeah, around a -1. -0.5 to -1. So I want to thank you for your attention this morning. I think we’re running five minutes early, so I can answer any questions that anybody has. And this is my email at the bottom there. [email protected]. Feel free to email me with any questions. And this is a picture of Alpamayo, a pretty mountain in the Peruvian Andes. If we have any Peruvians out there, you’ve got some good mountains down there. And I’ll open up for any questions. Okay. So… Dr. Sah asks: Have you tried head down positioning to reattach an inferior detachment, if there is a bubble in the AC on the first postop day? I don’t think they have to go head down, just because that’s so inconvenient for the patient. I would just fill the AC with air. And then leave them for 45 minutes, laying flat in your office or back in the theater. And then leave enough of an air bubble to cover the entire graft, so that if they lay flat, it’s being covered. So again, it’s the initial pressure. And then a large enough air bubble that clears the inferior iridotomy, that allows them to lay flat, and have that inferior part. So the next question is: Dr. Pandya says — the main indication for DMEK? In the US, it’s Fuch’s corneal dystrophy, but in India, I think it would be pseudophakic bullous keratopathy. Dr. Paracha says nice surgery. Thank you. Dr. Al-Jassar asks: Loading the graft in the cornea, what are the take-home tips? So loading the graft — I guess that would be injecting the graft. The main take-home tip is to have the right incision size. If you’re using the modified Jones tube or the Geuder, it’s a much smaller incision. If you’re using the Viscoject injector, like I just showed, you need a 3-2 incision. Don’t be afraid to use the anterior chamber maintainer. As long as you remove it before you withdraw the tip of the injector, you’ll be fine. Dr. V asked: Do you use SF6? Many surgeons use SF6, but I don’t think it’s necessary. I think you use DMEK the way that you learn it and then stick with it. I use air. I keep a full air bubble for 45 minutes in the holding area, the postoperative area, and bring them back in the theater and remove enough air to clear the inferior iridotomy. So a full air bubble for 45 minutes. Now, that eye is not tense, tense, tense. It just is probably in the 30s, pressure-wise. 25 to 30. Okay. Another question. During rebubble, any risk of graft displacement? That’s a good question. If there’s still an air bubble in the anterior chamber, and this is where SF6 is kind of helpful, because it sticks around longer — but if you do have a bubble, it’s very easy to rebubble. You just have to carefully enter the anterior chamber, release a little bit of fluid, and enlarge that bubble. If it’s several days out, you have a detachment, and there’s no air in the anterior chamber, you have to be very careful that you’re not folding the graft over with any air bubble that you place in. So again, you’d have to enter the anterior chamber carefully, make sure you don’t hit the edge of the graft, go centrally, and put an air bubble in. So it can be difficult. Okay, Dr. Pandya asks: Any other media except Optisol? So I know in other countries where you’re harvesting your grafts you use MK medium, because that’s for 48 hours after the graft. In India, for example, you get the cornea, and you use it immediately, in the next few days. So you could do this through MK. You just have to use it in the first 48 hours. I just show Optisol, because that’s the medium term media. That’s what we use in the United States. So you could do it in MK. Dr. Paracha asks: How much is the learning curve period for this technique? I would say in your first 50 cases, something like that. I think you need to have a proctor who knows what they’re doing for the first five cases. And then I think you can handle it. After preparing somewhere between 5 and 10 donors, you can do it very reliably and surgically. You just need kind of a coach in there at first, to make sure you can get yourself out of any predicaments that happen when you’re doing the case. So proctor for the first five to ten cases would be ideal. Maybe the final question here. Dr. V asks: Do you try to get the DMEK scroll oriented in the right direction in the injector before insertion? A lot of surgeons do that. They use what’s called the V sign, where you can see it’s in the correct orientation. But the issue is, if you’re using the IOL injector, you have to rotate the injector to get it in the eye, and then you would have to reorientate that once you’re in the eye. I don’t feel that’s necessary. However, if you’re using the glass Geuder injector or the modified Jones tube, it could be helpful. And so it’s not a technique that I use, but a lot of surgeons do. There’s many techniques. I feel like the handheld slit lamp is helpful for me, because it doesn’t rely on any preceding steps to ensure that it’s good. As long as I know the graft’s in there, I can see if it looks like the hat or not, and I’m comfortable with that. Dr. Ziiatdinova asked: What do you think about PDEK? I think harvesting the tissue is very difficult. You have to use the big bubble, and it can be traumatic to the endothelium as well. I think there’s a place for it. If you were limited somehow in the tissue that you got, the PDEK would be helpful, but if you’re able to get tissue that’s, like I said, 60 years old or so, you would be set just doing DMEK. Honestly, I haven’t seen enough PDEK to be able to see what the advantages are. What is the ideal age to do the graft? Dr. Babu asks. 60 years old would be the target on the donor tissue, I feel. If you can get around 60-year-old. It’s the nice balance between healthy young tissue and ease of unrolling and unfolding. I think that’s it. I don’t see any other questions. Yeah. I think that’s good. So I appreciate your time. Looks like we finished on time. And thanks again, Orbis.

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March 5, 2018

Last Updated: October 31, 2022

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