Lecture: Penetrating Keratoplasty: Intraoperative Steps and Management of Complications

In penetrating keratoplasty, the surgical steps are crucial to ensure a clear, healthy graft! This webinar will focus on intraoperative steps like suturing techniques and graft alignment as well as avoidance and management of common complications. Log on to hear frequent visiting faculty Dr. James Lehmann share his tips and wisdom.

Lecturer: Dr. James Lehmann, Cornea Surgeon, Focal Point Vision, San Antonio, Texas, USA


DR LEHMANN: Hi. Good morning, everybody. My name is Dr. James Lehmann, and I’m gonna be doing the lecture today. Let me just share my screen. Okay. So today I’m talking about penetrating keratoplasty. I gave a similar lecture a couple of years ago. And it’s gonna be kind of the same topics. Maybe just updated, and some improvements from the last one. Here are my disclosures. None are relevant for this talk. And we’re gonna start with a few poll questions. And Lawrence, who is running this from Orbis in New York, will tally up our answers. So this is for the audience. I have performed penetrating keratoplasty never, 1 to 20 cases, 21 to 50 cases, and 51 cases plus. So go ahead and answer that poll. And in about ten seconds, Lawrence will show us the answers. This helps me to know kind of a little bit what level we’re at with the audience here. Okay. So never. So 86% of the audience either never or the very beginning. That’s good to know. That’s what this lecture is directed for. So which of the following is not a contraindication to a PK? Not a contraindication. Active OCP, untreated exposure, keratoconus with a scar, or active graft versus host disease. Which of those four diagnoses is not a contraindication? So go ahead and put your answer there. And Lawrence will tally them up for us. Okay. So 67% answered keratoconus with a scar. Correct. And then another question here. When performing penetrating keratoplasty, which is true? The donor should be larger than the recipient. Or the recipient should be larger than the donor. Which one is true? All right. Go ahead and put your answers in, and then Lawrence will tally them up for us. All right. 83% answered the donor should be larger than the recipient. And then the last question here: If a patient has a corneal scar and a mild cataract, the surgeon should do a PK3. That’s a corneal transplant and cataract extraction with IOL implantation. Or the surgeon should just do the PK and then months later come back and do the cataract, or the doctor should take the cataract first, then do the PK. Or the surgeon should perform DMEK. So we’ll get an answer here. Go ahead and tally them up for us. This is a little more complex. Corneal scar and cataract. Let’s see what the totals are. All righty. So we’ll get into that a little more. So here are objectives of this lecture. Number one, to understand preoperative planning for a PK, and then to learn about the intraoperative steps. Then we’re gonna learn how to avoid and manage intraoperative complications. So the preoperative part is important, because then you’ll have less problems intraoperatively. So a little bit of background. Penetrating keratoplasty has been done for hundreds of years, but it didn’t really get done in earnest until the ’50s and ’60s with Dr. Villejo in New York. This was a double bladed knife with graft and transplant. This was a picture I saw a long time ago. It used to be one size fit all. Every patient who was bad enough to need a transplant would end up getting a PK. And now we know that’s not the left. On the upper left is a PKP, to the right is a DALK, 95% thickness, leaving behind Descemet’s membrane and a little bit of the posterior stroma, then there’s a DSAEK on the lower left, an endothelial transplant where you have Descemet’s membrane, endothelium, and a little bit of posterior stroma, and DMEK, which is just a little bit of endothelial cells and Descemet’s membrane, and then you have Kpro, which is a PK with a center of a plastic cylinder, so if the rest of the cornea vascularizes and rejects, the center remains clear. In the United States, this is a little trend over the last 20 years of transplants. Basically 50,000 transplants are done a year, and in 2011 is when more EKs were done than PKs. Now PKs are leveling out around 17,000 a year. Of course, there was a dip last year, because of COVID. In the United States, the two main reasons to do a PK are keratoconus and a repeat corneal transplant. In India, for example, the indications are different. Mostly therapeutic PKs done for ulcers and then an optical one done for a regraft. That’s the most common reason in India. In Colombia, for example — I misspelled that, sorry about that. Spellcheck. Bullous keratopathy, corneal dystrophies. From 2018. So here’s an example of a failed graft. You can see a vascularized graft with superficial vessels. Doesn’t look like too many deep ones there. This would be a pretty common indication for a graft here in the United States. Of course, you want to figure out why it failed. Did the patient stop coming in? Did they stop using their drops? Is there some uncontrolled inflammation going on that we don’t know about? And you want to sort all these things out before doing another one. Here’s a picture of fungal keratitis. We have these too in the US, where a patient will have an infiltrate that we can’t treat with drops, it won’t get under control, and we end up having to do a therapeutic transplant. So let’s talk about some contraindications to corneal transplantation. These are reasons to treat the surface, treat the eye, before doing the transplant. Severe keratoconjunctivitis sicca. Severe dry eye needs to be treated before you do a transplant. Because if you don’t, they’re gonna fail. The surface isn’t gonna epithelialize. They’re gonna have epi defects, et cetera. Stevens-Johnson syndrome, of course. You probably wouldn’t be doing a PK in the short term on these patients. But even afterwards, if they have a dry ocular surface or keratinization, it’s not a good milieu in which to put in a new cornea. OCP is something we see in older people here in the United States. These pictures here show some scarring, symblepharon. This would be one you would have to be quiet and they would have to have what we call a wet eye. I know that sounds kind of simple, but basically they have to be able to make tears. You don’t want to have a keratinized surface, just like in Stevens-Johnson’s, or else they’re gonna reject that cornea. It’s not gonna thrive. Limbal stem cell deficiency is fairly common. If it’s unilateral, you would do a stem cell transplant in that eye first and let that heal up and come and do a PK later. If it’s bilateral, then you got some problems. You either have to do a living related donor or talk about doing a Kpro, if the surface is good enough for that. And then exposure. That would be like ectropion or if they have lashes coming in, or they can’t blink. All those things have to be addressed. And at least have a plan for it, when you do the PK, so that you don’t have the same pathology come back. Some more contraindications — active infection. Unless you’re doing it for that reason, if there’s an active infection somewhere, you want to treat that first. And HSV, you want to put the patient on Valtrex prophylaxis, or acyclovir, depending on your country. Around the time of surgery and even afterwards, to prevent recurrence. And you want the eye quiet before you do surgery. This is kind of the one I see the most. Uncontrolled glaucoma. And so glaucoma would be a great reason for a graft to fail. And you have to… You have to get that fixed. A tube or medicine before you do the surgery. Because if you just do the transplant, it’s gonna fail with that high pressure. I’m gonna go ahead and open up the question part. Here you go. Okay. I’m gonna go back to play. Okay. So… Already getting a few questions in here. One of them is: When do we have to continue the steroid? We’re not gonna talk too much about postoperative regimens, but basically… A steroid — they’re gonna need to be on it for life after a corneal transplant. In some form or fashion, once a day, twice a day, every other day, but everybody needs a steroid for life after a corneal transplant. The last contraindications are: Multiple previous rejections. So that would be if they’ve had two or three grafts and they failed. If you do another graft, guess what? It’s gonna fail. So you have to think that through and decide about the best next step for the patient. And then an inability to care for the PK. So if the patient is… Well, demented, or they have developmental delay, or they’re not in a social situation in which they can care for the graft, you have to think about this. Especially if it’s only one eye. And if they’re better off not having surgery. Okay. So a little bit about donor cornea selection. Here in the US, before we do a case, we send a request to the eye bank. And then we receive a tissue detail form like this, that goes over all these things, like the age of the decedent, the date of death, how long ago it was, how long the body was cooled, what the cell count is, and we get a picture of specular microscopy down at the bottom. So things to look for on this form are the age, of course, the cell count, and the picture is good to look at, and make sure there’s not a lot of pleomorphism or polymegathism. I also want to make sure I don’t have any white arcus that comes into the graft. And of course the other things such as the date of death — normally you want 12 days or sooner. Most of the countries I visited, they use them much sooner. We use them a little longer in the United States. And the standard of preservation. It’s about 20 hours that you would want to use the cornea. There’s a question here from Mr. Julio DeLeon about opacifications near the tracts. Okay. We’ll get to that. Why not younger than 15 years old? You can. That’s a good point. The thing is… So in PK, if you use a cornea that’s 4 years or younger, it’s very pliable. It’s very soft. And it’s a little bit more difficult to control the tissue in the surgery. Also, you have a higher chance of it getting distended and having higher K values, keratometry, afterwards, if there’s high pressure. Also, you kind of don’t know if these patients are gonna… Maybe they’re gonna end up having keratoconus, other types of issues. So it’s not a hard stop at 15. It’s not even a hard stop at 65. It’s kind of guidelines there. But I generally don’t like using young corneas. For DSAEK I do, but not generally for PK. The hard stop for me would be around maybe 3 to 4 years old. But you can use younger than 15, of course. These are just some guidelines. These are the donor cornea solutions. In the US, we mostly use the Optisol. But there’s great solutions across the world. And in Europe, for example, they use organ culture. They don’t really use the intermediate term storage like we do and refrigeration. And in terms of serologic testing, all the donors undergo these tests. Including COVID. And the main contraindications in the US — this was from a long time ago, but it’s mainly hepatitis that came back positive, not to use the donor, if there was a positive serology. At the eye bank, they put the corneas in these viewing chambers. You can look for endothelium, exposure patterns, and document the clear zone. So all that information is important to view prior to using the cornea. And of course you have the specular microscopy. And the videos here you can see from the left to the right that… Obviously the left is beautiful. Nice uniform cells. All the way to the right, where there’s dropout with guttata, which — you would probably not want to use that cornea. And then in preoperative planning, let’s talk about that. So there’s different element to the presurgical planning. And this is what’s gonna help you to not have complications during the surgery. So that begins with anesthesia. You’ve got to think about the patient’s lens status. If it’s a failed PK. And then some unique situations we’ll get into. So the goal for anesthesia in a PK is: You want the eye not to move. You want the patient comfortable. Those are the two things. If the patient is uncomfortable, they’re gonna squeeze. That’s gonna cause positive pressure and you’re gonna have problems. So in the US, I generally do probably 95% of these under local anesthesia. That’s a retrobulbar block. It’s sometimes a van Lint block, which is in the facial nerve right by the eye, and with facial sedation by the anesthesiologist. He’s giving them Versed, some sort of anxiolytic. I generally shy away from using propofol during the case, because patients will wake up and kind of be startled and tend to squeeze. There’s a question: Can we use donor corneas with prior refractive surgery? Yes, for endothelial surgery, but I wouldn’t use post-LASIK cornea for a PK or a DALK. I would use it for EK or DSAEK or DMEK. Back to the anesthesia. So again, I generally use local, but there’s not a problem using general if you want to use that. Okay? Actually, in most countries I’ve visited and done PKs, the cases are done under general aesthetic. So again, you want the patient to be able to cooperate during the procedure. This goes with the patient’s age and mental status. So the younger the patient, the more they’re gonna not be able to stay still. Also, if you’re gonna need to do additional intraocular procedures like an open sky cataract surgery or fixating a lens, which — I’ll show you some videos later — those may be something that makes you want to do under general rather than with a block. And that risk for suprachoroidal hemorrhage. If the patient is older, I generally would stop blood thinners on all these patients, but general anesthesia, technically, in my opinion, would have less risk of suprachoroidal hemorrhage, because the patient would be less likely to buck. Bucking means kind of squeezing. Or to be uncomfortable and increase that posterior pressure. So possible complications of the retrobulbar block. This goes for any kind of eye surgery. We know that. Globe perforation, intravascular injection, retrobulbar hemorrhage. You need to have good practice being able to do a good nerve block before doing it for a PK. But generally you can do these cases under local anesthetic. Now we’ll talk a little bit about lens management. So there’s kind of five scenarios that I kind of thought about in my mind. There’s a mild to moderate cataract. There’s a dense to mature cataract. There’s a dislocated IOL. There’s a poorly fit ACIOL and there’s aphakia. So all of these situations require a little bit different approach. The most common scenario is a mild to moderate cataract. So in this, I recommend leaving the cataract alone. And then returning 6 to 9 months after you’ve done the corneal transplant, to do the cataract surgery. After you’ve done some suture management. Okay? So we’ll get into that in a sec. But why do I say that? Because any kind of residual refractive error that you have after you’ve removed the majority of stitches and the patient is stable with a healthy graft… You can treat at the time of cataract surgery. And make it more equal to the other eye. So they don’t have high hyperopia or high myopia. And so what I typically do is an interrupted and running pattern. As you can see on the right here. And this is four months after corneal transplant. The sutures are very tight. I use 12 interrupted, 12 running, and I’ll bring the patient back at 4 months, and then I’ll do topography. And that topography will then show me where the tight sutures are. Those would be the steep axis, as seen on the topography. So in this picture, the one on the left — it shows the steep sutures are around 50 degrees. 30 degrees. Okay? So then I look on the patient and I would remove those sutures. Let me see if I can direct here. Let’s see. Okay. Mouse. And then… Okay. That’s not what I… Let’s try to do… Spotlight. Okay. Oh, sorry. I was just trying to show… I was trying to be able to point on my screen. But somehow they don’t let me point on my screen. Anyway… So back to this. So I’ve removed those two sutures. And then I bring back the patient a week later. I mean a month later, excuse me. And then I do the same thing. So now this is five months post-op. And I do topography. You can see the steep axis is 75. And you can see a nice line of astigmatism there. So I would selectively remove the sutures on the tight axis. And so I do that, and then I bring the patient back in a month. So now this is 6 months post-op. And now you can see we have pretty good cyl. It’s average K around 44.5. And about two diopters of cyl in this topography. So at this point, I know they have good corneal shape. And then I can go ahead and do the cataract surgery. So I would plan the cataract surgery at this point. I would leave the rest of those sutures in. For the long term. And only remove them if they became vascularized or they broke. So I always get that question. In these webinars. Like, how do I manage the sutures? What’s better? Is it a continuous or interrupted? So this was from a lecture last year, during COVID. One of the docs in India sent a question of: What are the advantages and disadvantages of continuous and interrupted sutures? So the bottom line is: Once the sutures are removed, there’s no difference. That’s from an old study, like 20 years ago. But to me, the combination gives me the flexibility to start removing sutures a little bit earlier. Like, I can do them at 4 to 6 months, instead of having to wait a year or nine months with interrupted sutures. Additionally, when you just have interrupted sutures, you really don’t want to remove two sutures that are next to each other. Because that creates an area in which it’s gonna be weaker. You don’t have that problem with the continuous suture. So at the time of surgery, when I place the interrupted sutures, I place them tight. When I place the running suture, I leave it kind of loose. And the idea behind that is: I want that running suture to stay forever, if I can. To me, and I don’t know if this is true, but it seems it would give a little more protection if they bump the eye. But it provides me kind of a framework in which to remove the tighter interrupted sutures early, and not have to be so concerned about leaving a weak graft-host interface. So my vote is a combination of continuous and interrupted sutures. The last thing I’ll say on this topic is that it looks a lot prettier when you do a continuous suture. So other doctors, when they look at your corneal transplant, they’re gonna say… Wow. That looks nice. I can’t do that. I’m gonna send my patients to Dr. Natajaran in India. Or if they see these interrupted sutures, they’re not even, they’re different lengths and everything, they’re gonna be like… Man, next time I’m gonna do it myself. I’m kind of saying that tongue in cheek, kind of in jest, but the bottom line is there are some practical and some aesthetic reasons to do a combination. So if you have a dense or mature cataract, this is a case from 2009 in which a patient had a ruptured globe. Violated the lens capsule as well. At this point, you can’t leave that lens in there. If it’s a very dense cataract, you don’t want to leave it. So you would do an open sky cataract extraction. In these situations, you can use a variety of lenses. You can use a rigid PMMA lens, like the Alcon CZ70BD, you can use a silicone lens, but what you don’t want to use is a one piece acrylic lens. Because when you do an open sky cataract surgery, the capsulotomy is not just like a phaco. You can’t be sure that you got that lens completely in the bag. So if you put an acrylic lens and any of it is in the sulcus, guess what? You end up having UGH syndrome afterward. So you can put in a silicone or a PMMA lens, but don’t put in a one piece acrylic lens. And if you’re worried about doing the calculations, use Ks of 45 and 45 and go ahead and take the axial length from the other eye. And that generally tends to work. So this case, afterwards, looks better. He was able to see well. And I still see this patient. This happened when he was in high school. And now he’s like a dad. And I see him what, now, 12 years later. Okay. So a Flieringa ring. I always get questions about the Flieringa ring. Why do we use the Flieringa ring? It just adds time to the surgery. I think it’s very important, if the patient is gonna be aphakic at any point in the procedure. So what does that mean? That means if you’re doing cataract surgery, for some time, you’re gonna take out the cataract before you put in the IOL. They’re gonna be aphakic. So if you’re doing a cataract surgery, you’ve got to put in a Flieringa ring. If the patient is aphakic already or if they have a dislocated IOL, you’re gonna need to use one of these rings. Because they work like a box kite. So this was a question that I got in 2020. What’s the advantage? And I thought these two pictures kind of show a good idea. Basically the eye will deflate once you take out the cataract. Or if you unroof an eye, if you take the cornea off, and there’s no Flieringa ring, it’s gonna shrink like a little deflated happy face balloon like that. But if you have the Flieringa ring, it’s like a box kite. It gives some structure to the eye. It creates depth in the anterior chamber. And allows you to put a lens in the sulcus much easier. If you don’t have that Flieringa ring, the posterior capsule starts to rise up. There’s not really any space between the posterior iris and the posterior capsule. It’s very difficult and more dangerous to put in a lens at that time. So save yourself a headache. Take the time to put in a Flieringa ring. Here’s a dislocated or poorly fitting IOL. What do you do in this scenario? What’s wrong with this picture? Obviously you’ve got a cornea that’s not happy, it’s cloudy, and you have a one piece acrylic lens in the anterior chamber. That’s a no-no. That’s why this cornea is unhappy. So you have to remove that lens. Some people would even say you can remove that lens and see if the patient will recover. And get good vision. If the cornea will recompensate and not stay cloudy. But in this situation, if you were gonna do a PK, which you could do a DMEK or a DSEK, you would have to remove the IOL for sure. So… It’s basically an IOL exchange. And to put a new lens in, if there’s no capsular support, you either have to suture a lens, and you can use prolene, or you can use Gore-Tex. Or you can do a Yamane technique, where you do intrascleral haptic fixation. So I’ll show some videos on this later. Most of the patients that have a dislocated or poorly fitting IOL — they have endothelial decompensation. Not necessarily like a corneal scar. So in these situations, you’re not really doing a PK. There may be a few. Okay? And I have some videos. But most of the time, you’re gonna end up doing a two stage procedure in which you fix the lens problem first. And then you come back and fix the endothelial problem. Aphakia — these may just have endothelial problems, or they may have a full thickness scar or something. And it’s basically the same situation. You either have to do a combined Yamane, or you have to do a Gore-Tex suture/prolene sutured lens. When did I decide between these? I’ve migrated to doing the combined Yamane technique. The sutured IOL is totally fine if that’s all you’ve got. And here’s pictures of lenses you can suture. The CZ70BD by Alcon. Many companies make a similar one. It’s PMMA and has those little eyelets that you can use to fixate. And there’s the Akreos lens by Bausch and Lomb that has the openings in the haptics that allow you to suture the lens. What’s the difference between Gore-Tex and prolene? Gore-Tex may not be available where you are. It’s definitely an off-label use of the Gore-Tex. It’s designed for suturing heart valves. And the needles aren’t right. You don’t use the needles. You use just the suture. And the prolene is much more available. Dr. Koram asked: Do you not consider an ACIOL for aphakia or IOL exchange if you’re going to do a PK? I think that that is… I think that’s a possibility. And if you don’t have other technologies available, I think that that’s a fine option. However, I don’t think it’s the ideal option. It’s not easy to put an ACIOL in at the time of penetrating keratoplasty and ensure that it’s gonna sit nicely. You can do it, and it takes some practice. You should do a PI. And the patient can be fine. But there’s definitely gonna be a higher chance of inflammation. Of corneal decompensation of the donor later. Because you have an AC IOL right next to it. These eyes are complicated, and there’s not just one size fits all right answer. And so I think you have to take it on an individual basis. But I think that’s definitely a reasonable option. If some of these newer technologies aren’t available to you. Presurgical planning. We’ll move on to failed PKs. So another question I get is: If you have a failed PK, do you repeat the trephination? Or do you try to take out the graft that’s there, without retrephining? I generally like to do repeat trephination. Because most of the grafts people had that were old or smaller, they may be decentered. If it’s a graft you did, and it was recent, and you want to put the same sized graft in, like let’s say that you just did a therapeutic graft, and now you have to do an optical graft, you can just dissect it and remove the graft that you put in. But if they had been in there a long time, I vote for retrephining. And then if they do have a failed PK, let’s say a patient — you’ve never really seen comes to you and they have a failed PK, and you’re trying to decide: Do I do a PK or do I do a DMEK or a DSEK? The most important things are to think about: What was the best corrected vision prior to the graft failure? Was the patient happy in glasses or in contacts? Because if that’s the case, you can do an endothelial keratoplasty rather than a repeat PK. But if they have an ectatic graft, or it’s vascularized, or scarred, or they never saw well in glasses or contacts, then I would go ahead and go for a penetrating keratoplasty. And so here’s a question. Excuse me. Here’s an example. This was a patient who presents with a failed PK. You can see edematous. Right in the middle of the picture is a bulla on the epithelium. And so what would you do in this scenario? They had good previous vision, but they had graft failure with corneal edema. Very minimal scarring. In this situation, I think endothelial keratoplasty would be the better option for that patient. And I kind of do DSEK in these patients, more than DMEK. I think it’s hard to get the DMEK to stick in these patients. So I generally do DSEK. And I would do the DSAEK in the area of the — smaller than the area of the transplant. So I would do a 775 DSEK. This is a vascularized scar graft. You can’t off the patient endothelial keratoplasty. That’s not gonna help anything. You wouldn’t have enough of a view to do it. Here you have to do a repeat PK. Did they have good limbal stem cells? It doesn’t look like it. You could do impression cytology and see if there’s any goblet cells, any corneal epithelium there, or is it all conjunctival epithelium? If that’s the case, you’re gonna have to do a stem cell transplant from the other eye and let it heal up before doing a PK. Another option, if you don’t have the other eye to do anything on, a Kpro may be the best option in this patient. Dr. Alam just sent a question in. It says: In the case of aphakic bullous keratopathy, would you consider an SFL/Yamane, or two stage? I prefer two stage. The Yamane can be difficult, you can have bleeding, virtuous prolapse, all these things that make it a little bit trickier when you’re trying to do the endothelial keratoplasty. Plus I think it’s a little more traumatic on the graft to put that in an eye with all the inflammation from the Yamane or sutured IOL. So I have moved to doing two stage procedures in which I fix the lens problem first and then I let the patient heal for about a month or a month and a half and then I’ll go and do a DSEK in those scenarios. So this is a picture of a Kpro like we talked about in a patient with a vascularized cornea. That’s gonna be your best choice. Another question from Dr. Mohammed Adli. He said: Who usually performs the retrobulbar block? Is it the anesthesiologist or ophthalmologist? I think it depends on your hospital situation. I operate with an anesthesiologist who does great blocks. So he does them for me. When I visited Jerusalem Eye Hospital, the anesthesiologist did the blocks for me as well. But sometimes it’s the resident who’s gonna do the blocks. Whoever is best at them and the most comfortable, in terms of relationship with the surgeon. So let’s get to the fun part. Surgical technique. We’re gonna talk about these different steps. Beginning with recipient eye preparation. So… We talked about the Flieringa ring. If you’re gonna do cataract surgery or they’re aphakic. When we prepare the eye, we want to measure the corneal diameter. We want to mark the center. And we want to determine the donor size. So my standard is 8.25 into an 8. So the recipient — 8.25. Excuse me. The donor 8.25, the recipient, 8.00. And I like to mark using an old-fashioned RK marker for the sutures. So here’s a video of the Flieringa ring. Okay? And… Basically you want to oversize it, where there’s about 2 millimeters between the limbus and the ring. And when you connect it to the eye, you’re trying to do episcleral bites. And you want to use a needle, either vicryl or silk sutures, that’s a spatula needle. Not a cutting needle. You don’t want to penetrate too deeply into the sclera. The passes you make do not have to be radial. They can be tangential, oblique, like this image. Because it doesn’t really matter. What you want to do is get it centered the best you can. And you want to do those little bites there. Some eyes are easier to do than others. But once you’ve done this, you have good structural support. Kind of fast-forward here to the end. And you can even — if the eye is kind of rolling down or something like that, you can kind of use a suture like — another suture stay to kind of move it more centrally in the microscope. A few more questions here. Do you do combined procedure for PBK or only corneal transplantation? Of course that depends on the situation. Most of the time for PBK, we’re just doing endothelial keratoplasty, not necessarily PK. And Patrick Atta asked: For Kpro, do you use a new cornea or the patient’s cornea? I generally use a new cornea. It doesn’t have to be a good one. Meaning it can have poor endothelial cells. It can have haze. It can have a small optical zone. It can be from a 75-year-old. But I use a new cornea in those scenarios. So we’ve got the Flieringa ring. We know how to do that. And in terms of measuring… In this video, I kind of go overboard and measure a lot and mark a lot. But I start with the horizontal corneal diameter and mark the center of the cornea and then do the vertical diameter and mark the center of the cornea. And that kind of tells me where I’m gonna use my little cross when I aim with the vacuum trephine. And I mark the center with a Sinskey hook. And this is the geometric center of the cornea. This is not the pupil. Okay? And then I put a 75 trephine on there and I make sure that’s centered by rotating the eye around a little bit and mark the epithelium. And then I can use a marking pen. You don’t have to do all this. You can just mark the center. But I did this for illustration. This helps you to center the best. And now I’m using the RK marker to mark where I want to put my sutures. That makes life easier. So what’s the benefit of all these marks? All righty. I’m gonna go back a little here on the video. Now, check it out. When you trephine this — I used a smaller trephine than I’m gonna use for real trephination. So this helps me use the Barron trephine to mark the center of the cornea. That’s the cross hair. And you can look around. And as long as you’ve incorporated all the dots, you know when you’re on to that vacuum trephine that you’re centered on the cornea. And then the RK marks are really helpful, especially for passing the first two sutures. And so the next video is that host corneal trephination. So this is the same case. And then this is what I was talking about. Look here in the middle. I’m using the cross hair for the dot. But then I’m looking to make sure all these dots I did on the smaller trephination are inside mine. That means I’m not grossly decentered. I’m turning. Some people like to enter the AC, others like to stop and enter the AC with a supersharp. It doesn’t matter. Whatever you’re more comfortable with. If you cut all the way to where you get a little aqueous you have a more uniform cut, but it also decompresses the eye fast and it can make people a little more nervous and stuff. So entering in a controlled manner where you have the scissors going the same way every time is fine. So then I entered in a controlled manner. I’m right-handed and I entered right here. Now I’m putting in a cohesive viscoelastic, and then using those curved corneal scleral scissors to find that gap. The main key when you use these scissors — you don’t want to forget this — is you can put them in oblique, but you have to rotate them perpendicular to the cornea. So that you don’t get a shelf on the incision. So that the incision becomes vertical like this. If you end up cutting with the scissors kind of oblique, then you get what we call a corneal shelf. Where the cut is like this, instead of like that. Now, that’s not the end of the world. It sometimes gives you a little better framework if you’re doing it in a very thin cornea, like a pellucid. You want to kind of leave a bigger shelf, because then you have more surface area to suture into. But in most cases, it’s not necessary. So you saw that I went around to where I was comfortable, in this direction. And now I’m coming back with the other scissors. The other direction scissors, back to this way. And with my left hand, I’m kind of retracting back the cornea. And you kind of pull it centrally so that you expose this little gap, and make sure that you’re in the line that the trephine already cut. And so you want to be able to cut and then you can go back, and if there are areas that you didn’t like, that you left a shelf, you can go back with Vannas scissors and cut that to get a more even graft-host interface. So again, start with the good marking. Then you’re gonna trephinate. You go as far as you want, then you enter in a controlled fashion. You place viscoelastic. Cohesive. And then you go in and you use this left hand to retract centrally the cornea so that you can get those in the groove there. And then you make slow, controlled cuts all the way around. With the scissors as perpendicular as you can get them. Now, donor prep. Obviously you do this before you did what I just showed. Because you don’t want to be having that open globe and coming over and doing this. I like to do donor prep under the microscope. Because it helps me with centration. I hate cutting an off-center PK. It is so frustrating and it looks not pretty. So most places I go, I see the surgeons doing this, and they do it on the Mayo stand without a microscope. But you can use the microscope. So I use a little purple marker, and I mark the central area here. Of the Barron trephine. And that allowed me to center it better. And then I punch it. And I use a lot of force. And then I rotate it around and I use 0.3 sutures, 0.3 forceps to kind of rotate, and that makes sure there’s no connection to the graft. And then I put a little bit of Optisol back in this well. And then I cover it up. And then I go do the trephination of the recipient. So obviously you want to prep the donor before the recipient. I should have shown that video first. A little side note: These are called temporary Kpros. These are cases where the cornea surgeon is doing the case alongside a retina surgeon. The retina surgeon doesn’t have a view. So you want to take off the old cornea. These are mostly penetrating trauma or hyphemas, or something bad. And so you’re gonna put — you’re gonna trephinate the cornea, you’re gonna suture this temporary Kpro onto the eye, and they’re gonna do the retina part and you’re gonna take this part off and you’re gonna put the new cornea on. You don’t want to put a nice new cornea on and then have the retina get knocked in there with the vitrector, blah-blah-blah, for an hour. So that’s what a temporary Kpro is. They make them in different sizes, but you kind of want to do a little bigger than your normal PK when you’re doing these. Okay. So another situation. This is open sky cataract surgery. This is from a case that I staffed in China during an Orbis trip. I want to say maybe about ten years ago. So we’ve taken off the cornea. The patient is under general anesthesia. And you can see the cataract is pretty dense. So this is the trainee doing the surgery. He or she put some Trypan blue, and then the type of capsulotomy that you want to do in this scenario is just an old-fashioned can opener style capsulotomy. You don’t have to do a CCC. So you just want to make nice easy cuts, where they’re continuous, so that you don’t have a tag that runs out. And you just go all the way around. So I’ll move… So the surgeon is doing that. The capsulotomy in this area has been achieved and now the surgeon is continuing, and now we’re going over here, slowly, slowly, bringing everything to the middle here. You’re just trying to do them close enough together that you don’t have a tag that runs out. You verify by freely moving this cap, nothing is coming with it, so I know we’re pretty good. So now you remove the cap and you’re gonna use the cystotome to elevate the lens. The lens wants to come out. Even if they’re big, they want to come out. You don’t have to have necessarily a dilated pupil. So you elevate one pole of the lens and use the cystotome to kind of spin it out. And you can see that big old guy. Look at that. Holy moly. Okay. Now the cataract is removed. And now not much cortex there. The surgeon here is putting some cohesive viscoelastic to create a potential space between the iris and the capsular area. And this is a three piece silicone lens. You put that first haptic underneath the iris. And then with your second one, you grab the trailing haptic, and then you pronate your arm, you rotate down, tuck that trailing haptic under the iris, and then you let go. And then as long as both haptics are under the iris, you’re kind of in good shape. Then you can push down on the optic, you can coat it with viscoelastic, and move on to the corneal transplant part of things. Now, many questions I get in open sky is: Do you have to do cortical removal? Okay? It’s not the same. Most of these are mature cataracts, and you didn’t really do hydrodissection. So there’s not quite the same cortical plane like you have in cataract surgery. So when you remove them, you can kind of see: You can get a Weck-Cel. You moisten it, touch on the capsule, and clear any cortex that’s around the central aspect. And you can leave the rest that’s in the periphery. You don’t have to go in there with I and A and get all that stuff. That’s when problems happen. Because there’s not that expanded bag and space where you can put an instrument. It’s all compressed like this, because of the posterior pressure. So less is more in these scenarios. Dr. Adelle asked again: What should be the size of the donor cornea respective to the type of refractive error? I don’t think that really plays into it. I would say that you always want to oversize the donor. I like 0.25. And then fix the refractive error with contact lenses afterwards or cataract surgery if they’re older and have cataracts. Okay. So… Here’s another video of open sky. This is a patient that has posterior synechiae. You can see all that scarring where the scissors are cutting right here. Almost a pupillary membrane. And then they’ve had a previous transplant. You can see some stitches here. So I’m removing that pupillary membrane, and we’re gonna be left with kind of that dense cataract. And so… I’m using the cystotome. And I’m gonna go under there and try to retract the iris here. So that I can go and do a can opener-style capsulotomy that doesn’t leave a tiny little capsulotomy. I’m just gonna around and do this. Continue, continue. Using the push-pull to kind of move the iris out of the way. And you can see I’m just kind of scratching it and bringing them to the middle there. And then same thing in this lower quadrant. And the key thing is kind of elevating a pole of the lens, freeing it up. And another trick you can do is use a second instrument to push at the limbus, and that gets a pole up a little bit. Once you get the pole up, it really wants to come out, and you just spin that little bad boy out of there. Even big boys like that can come out. They want to leave. They don’t want to stay in there. Get that mean old cataract out of there. And using the Weck-Cel to clean that central part off. It’s a soft Weck-Cel. Don’t stick a dry one in there. And you can brush away on the central capsule any corneal material. You can use water to hydrate it and that helps to remove it as well. And once you’ve done that, there’s that water. You can blow it away and hydrate it. It just wants to leave. You can see fluffy edges here of it. And I’ve got a clear central capsule there. And now it’s time to put in the lens. So I’m gonna dry it off a little bit so I can see the anatomy a little bit better. And then viscoelastic underneath the iris to create that potential space. Where I can put that leading haptic. And I’m using a PMMA lens in this case. That’s a good example of the difference there. These play very nicely in the eye. Very inert material. So I’ve put that trailing haptic in. They’re just a little harder to do if the pupil is small. So I get that trailing haptic, I pronate my eye, I push down on the optic, I get it down under the iris, and I release it. And you just want that under. But it’s such a big optic. It stays so nicely back there. So… There’s that. We’re at 8:45. Okay. Here’s a case that I just did earlier this year. This is a situation in which they have a failed graft that’s cloudy. And they’re aphakic, because of trauma. I narrated it. You can find this on my YouTube page. But basically these are one of those cases where they’re aphakic. I’m gonna suture it in and do the Yamane. Here I’m marking. This is the most critical part. You do 2 millimeters, 2 millimeters, and 1. And I’m putting a Flieringa ring that’s shaped like an oval so I have room to pass the needles. Then I’m gonna prepare the cornea. And like I did in the other one, I put some Optisol and let it sit. I’m doing a paracentesis so I can put an AC maintainer. You want this eye firm as you pass these 30 gauge needles. And they’re attached to a syringe and now here I’m detaching it from the syringe and just leaving the needle there. Okay? And I’m doing the same here. Passing it through the sclera. And then I’m gonna begin the trephination. I’ve removed the AC maintainer. And now I’m entering in a controlled manner. And you can see how thick and edematous that cornea is. Now we’re left here with an open sky aphakic eye. I left a little hinge here, and there’s that IOL. So with one hand, I removed that… Starting to move that needle. And I’m gonna use just some tying forceps to dock the haptic into the needle right here. And now I’m doing the same on the other side. These are very pliable haptics. It’s called the Zeiss Lucia lens. And now you externalize the haptics. At the same time, I’m retracting the needles, and you use cautery to do a little mushroom at the bulb of the haptic. Same down there. And then you’re safe. They’re not gonna retract back into there. So now you can proceed with the corneal transplant part of it. So I put some viscoelastic, there’s the new cornea, and now I’m speeding this up. But I’m using my kind of initial painting there. And I’m gonna do my sutures. So there are the four cardinal sutures being placed right now. Once I have the four cardinal sutures in, then the next step is to… I refill the eye. Put some viscoelastic in there. And then I go ahead and do my 8 other interrupted ones. And now a running suture. And now closing the conj. And you’ll kind of see here at the end what the suture… You can see this case again on my YouTube page. But anyway, you can see at the end of the case there that we’ve got a nice lens. I’ll go back right there. You can see a nice lens there. I did a little iris work that I edited out, but basically: Cornea in place. And you can see kind of under the conj here, there’s that little bulb of a haptic. So patients do really well with this technique. A couple of questions. Aisha asked: Don’t we need to irrigate and aspirate cortical material? That’s what I was kind of talking about. It’s not as easy as it is during phaco. You don’t necessarily have to. The main reason you don’t have to is number one, most of these cataracts are very dense. They’re mature cataracts. So they don’t have a lot of cortical material. Number two, you can blow a lot of it out just with BSS. Trying to get a Simcoe or an I and A — a Simcoe gets better. But oftentimes, you end up pulling on the anterior capsule, where you were doing the capsulotomy. And it just creates kind of a headache and it’s nerve-wracking. If you can clear the central back of the capsule with a Weck-Cel or even the Weck-Cel — sometimes the cortical material will stick to it, and you can pull it. Those are fine, because the cortical material will dissolve on its own. So you can do it. If you’re gonna do it, do it with the Simcoe. But I’ve done a lot of these, and I find that it’s kind of a waste of time and the eye is open. So I don’t really like that. Dr. DeLeon asked for the Yamane procedure, do you do an anterior vitrectomy? In this eye, the patient had a prior vitrectomy done by a retina doc. But if it’s a Yamane, you can’t be doing that when there’s vitreous everywhere. You have to do a vitrectomy. But most of these eyes had penetrating trauma or RDs or something, and they had proper vitrectomy. Dr. Almousa asked: Why do you not go for a big CCC rather than can opener capsulorrhexis? I have tried both. And it’s very tedious to do a CCC in these eyes. Because you can’t put in viscoelastic and flatten the anterior capsule. It’s very round, because the eye is open. And it has a tendency to go out. Plus the pupil dilation, for whatever reason, when you open up an eye, it kind of comes down a little bit. It’s just not the easiest thing. You can do it. You can even phaco it. I’ve seen doctors use a phaco. But to me, it’s overkill and not needed. A CCC… It can be done. And I have done it before. I just find it’s… Not the most efficient use of my time. When the eye is open. Okay. So donor cornea suturing. So this is a video by Dr. Aldave. It basically shows really nice suturing techniques. So if you can remember anything from this talk, you want to learn how to suture nicely. And so you use those forceps the first time that have the two tines, and then you basically paint by numbers. Look over here — it’s how you grasp the needle, and what you’re shooting for is 90% depth. You don’t want it too short and you don’t want it too long. With your non-dominant hand, you kind of fixate on the recipient. And when you start pushing that needle, you want to see some arrow shaped striae occur in the recipient right there. That arrow shaped striae right there. Telling you you’re at the right level, and you want to come clear a millimeter anterior to the limbus. And when you pull it out, you want to do it in little pieces, not all at once, because it distorts the tissue too much. We do the 3-1-1 knot. You get it fairly tight. Everybody asks how tight. You want to say moderately tight. 3-1-1 surgeon’s knot and locked — very critical — into the donor. That’s what happened right here. He locked that knot. Let me see. Right before that. This is locking that knot forward. He’s locking the knot forward. You definitely want to do that with all the sutures. Otherwise, it’s gonna be loosey-goosey, and you don’t want that. So lock the sutures. Always towards the center of the cornea. And use those Pollack forceps if you’ve got them for the first pass of the needle. All righty. And the most critical suture is this next one. You want to align it very nice. And he had very good markings. So it helps. But you’re gonna see that V-shaped distortion of the recipient tissue. That tells you you’re in the right plane. You want to come out about a millimeter anterior to the limbus. After you’ve placed the four cardinal sutures, you can dry the cornea and you want to see a nice diamond shape here. And that tells you that you have good equal tension. And it looks real pretty too. Dr. Mathen asks: Do you prefer to bury the sutures in the donor or the host? I put them in the donor. Less likely to get vascularization and stuff. And then when I remove them, I always pull centrally with them. So that the knot doesn’t pass through the interface. Okay. So intraoperative complications. I’m gonna try to buzz through this. Basically we talked about anesthesia. If you need to put the patient to sleep, put the patient to sleep. When you do the Flieringa ring, you want to use a tapered needle. Or a spatulated needle. You don’t want to use a cutting needle. Because you’re gonna pass it too deep. How do you avoid improper trephination? You’ve got to be smart and you have to double check with your assistant or with the nurse that you have the correct trephine sizes. Always cut the donor first. And just verify before you do both that you have the right size. If you’ve cut it wrong, you don’t really have a good fix for that. So don’t do it. Materials for trephination. I like to oversize the donor 0.25. Some people go 0.5. I find that creates too steep a cornea. So 0.25 is what I like. Avoiding misalignment. You want to confirm that diamond shape. You can always remove one of the cardinal sutures and replace it if you need to. And then if you do have vascularization and bleeding, you can epinephrine drops on the cornea, Tisseel on the anterior segment, thrombin — all these things, as long as you remove them. But if they have vascularization, you need a 360 peritomy and get everything off the cornea. There can be a lot of bleeding. It can be long. You just have to be patient. A way to avoid the iris: Don’t trephinate the iris. When you see aqueous, you stop rotating. If there’s an AC IOL in the anterior chamber that you’re trying to remove, you have to cut it. Because sometimes it gets cocooned in the iris. To avoid trauma to the lens, you want to be careful when you trephine. Any sign of aqueous, you need to stop. If you’re not gonna be doing cataract surgery, you want to do preoperative pilocarpine to protect the lens as much as you can. During any iris repair, you want to lift the iris before you — so you don’t pass through the lens. Capsular rupture can happen with open sky, and you have to do vitrectomy at that time. You can still put a lens in the sulcus, but I would lean more towards that PMMA one, because it’s a little more rigid. As long as you have enough capsular support. You need to do a vitrectomy, and oftentimes a vitrectomy is easier to do than in phaco, because there’s not posterior flow of fluid going in, pushing vitreous forward. So it’s a little easier to do a vitrectomy. Dr. Mathen asked: Regarding oversizing, is there a rule for keratoconus? I do 0.25 for everyone. The only difference I do in keratoconus or pellucid is I’ll make a shelf inferiorly so you have easier suturing time. Again, if you do have a capsular rupture, it’s unfortunate, but it happens. You do a vitrectomy, and you’re able to have a good result still. If you have to put an AC IOL, it’s not the end of the world. And you can do that. Suprachoroidal hemorrhages — these are bad. We all know that. They’re risk factors — I think the main take-home is get their blood pressure under control. And have them discontinue any anticoagulation. I always send these patients for preoperative approval from their cardiologist. Especially if they’re older. You just can kind of minimize the risks. Also, if you’re doing anesthesia, I like to tell the patient — the anesthesiologist: Hey, I’m about to take the cornea off. Are they under? So you verify that they’re really sedated. You don’t want somebody choking — we call that bucking — choking on the tube and they… Buck and that’s when you get these problems. So… We went through the polls again. These are our final questions. So Lawrence, if you could pull the poll up again. Basically what is not a contraindication? You all did pretty good on this the first time. OCP, exposure, keratoconus, graft versus host. All right. Lawrence, go ahead and put up the… Answer. So we went from 67 to 88. That’s correct. Keratoconus with a scar is a great reason to do a transplant. And then we want the donor bigger than the recipient or the recipient bigger than the donor? This should be 100%. All right. Let’s see the answer. All right. 91%. Yay. And then the last question… Sorry. I’ll go back there. Sorry. Last question. If the patient had a… Sorry. Where did it go? It’s not letting me get back to that slide. Anyway, the last one is: If a patient has a corneal scar and a mild cataract, we want to do the cataract — excuse me, the transplant first, and then… All right. I think that’s it, guys. I’ll go ahead and pull out of here. I’ll stop sharing. And I have a few minutes to answer some questions, if y’all have any questions. It’s around… About five minutes here. Unfortunately, I’ve got to go to clinic. But I appreciate your time. We’ve got a couple questions. There are some questions about certification. So y’all can take that up with the Orbis folks. How much corneal neovascularization do you translate before going to a Kpro? Dr. Messenger… I would say… Figure out: Do they have a corneal epithelium? If not, do a stem cell from the other side. If you have a little bit, I would say less than 3 to 4 clock hours, I would be okay with. If it’s 360, the odds are that they don’t have good stem cells. And the it would be better to do… A stem cell transplant and a normal PK before jumping to a Kpro. And then lastly, Dr. DeLeon, how to treat superficial opacifications? Those are normally immune deposits. They can sometimes be from antibiotic drops. So I really wouldn’t be too… I would treat it with more steroid. Most of the time when it’s around the suture, it’s from an immune deposit. So I would treat with more steroid and see how that would work. And then… We already talked about continuing steroid. Thank you for your talk. Thank you. How do you treat corneal NV? Laser. It’s another topic. It’s hard to fix. I don’t have a good answer for that. Steroid is the easiest thing to try. Lasering doesn’t really help. Once you do it, it comes back. There’s a new thing using chemoembolization and mitomycin, but it’s an off-label use and I’m not that comfortable yet with that technology. How do I deal with anterior synechiae? If you’re not doing anything to the lens, I leave them alone. If you’ve got to take the lens out, I break them using a cyclodialysis spatula. And so… I’m gonna sign off, guys. I appreciate your time. And I hope to do this again in the future. Thank you very much.

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November 8, 2021

Last Updated: October 31, 2022

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