Surgery: Penetrating Keratoplasty

This video demonstrates a penetrating keratoplasty surgery in a 28-year-old patient with a history of infectious keratitis. Dr. Pineda performed the corneal transplantation and there was no need for cataract extraction as the lens was clear. He explained his suturing technique and also spoke about the postoperative medication and follow-up.

Surgery location: on-board the Orbis Flying Eye Hospital in Chittagong, Bangladesh
Surgeon: Dr. Roberto Pineda, Massachusetts Eye and Ear Infirmary, Harvard Medical School, USA


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Dr. Roberto Pineda: So, this is a 28-year-old man who had a history of infectious keratitis maybe one year ago. And we believe he perforated at the time. And this is the resulting scar. He has adherent iris to the backside of this scar. Pupil does not dilate. We’re assuming that the patient may have a cataract as a result of the perforation and collapsed anterior chamber.
So, we’ll do a full thickness penetrating transplant here. We’ll assess the lens after we remove the cornea and be prepared to remove the lens if needed.
Thank you, sir. And can you tell us, how did you do the biometry, how did you do the calculations? What are your plans for this?
Usually with penetrating keratoplasty, depending on the type of trephine you’re using, the manufacturer, you get a sense of the average keratometry over time. So with the trephine we’re using, I’m making the assumption that my post-operative keratometry will be 45 diopters on average for this eye. He had a history of having similar vision in both eyes prior to the surgery.
So we use the axial length from the right eye to determine the biometry, IOL calculation, for this left eye. Which turned out to be 21.5 diopters. And we plan on inserting, if needed, a 21.5 diopter one-piece PPMA lens.
And it looks to be a fairly vascularized cornea bed right now.
It does have about maybe four total clock hours of corneal vascularization. Sometimes in the post operative phase we will use sub con junk five Avastin to help with the vascularization. Also, we increase the steroid drops to about eight times a day for the first week after the surgery. Interoperatively I like to use topical brimonidine for vasoconstrictive purposes which is very effective. More so than I find using adrenaline or epinephrine combination.
So, we’ll go ahead and start by marking the optical center of the pupil which we’ll do with the caliper. This is my standard technique whether I’m doing a DALK or I’m doing a PK. It’s always important to determine the optical or geometric center of your cornea. Even if you’re going to use an eccentric trephination. So, things can be a little deceiving without this reference point. It seems like in Bangladesh the corneas are a little smaller than the standard. In the U.S. they’re about 12 millimeters. Here they seem to be about 11, 11.5 millimeters.
So, this is — I’m just measuring here. And this is definitely smaller. This is even smaller. So, maybe this is 10.5 millimeters. So, we’re probably going to be using about a 7 millimeter trephine for this case. Remember, we’re removing a scar here. So probably part of the endothelium is quite healthy. So, we don’t want to remove the unhealthy epithelium.
So, if we make this, essentially, 5 millimeters, or 5.25, we can measure. Usually when I do this, I start with the limbus. Identify the limbus and make a mark in the center. And same thing on the other side. Limbus first and then center. And then go ahead and do the same thing in the horizontal. That looks pretty good. Excellent. So, you can see, we’re right in center. And after we establish our optical center, we’re going to make our marks with the — our K marker.
These markers are not used for radial keratotomy anymore, but they make very useful for penetrating keratoplasty or DALK surgery where you need to make a mark. Now, you’ll notice that the magnification here is low. We do not need high magnification for this case. Which is important.
You can see the radial marks here. I like to make a secondary mark just on the inside here. These are where I hopefully will be passing my sutures. And it provides a nice kind of artistic look as well. Now, the next thing we’re going to do is we’re actually going to prepare the donor tissue. And the reason we’re going to do that is in case we do not need to remove the cataract. We want to have the tissue ready. So, we need to determine the size of our donor punch and the size of our vacuum trephine. So, the host punch is going to be 7 millimeter. The donor punch with this is going to be 7.25.
Now, remember, we really just care about the optical center here. We don’t have to worry about these — you’ll see these peripheral blood vessels here. We can make the graft a little bit smaller. One of the risks of graft rejection is proximity to the limbus. So, if we don’t need to be by the limbus, we shouldn’t be by the limbus. So, making the graft a little bit smaller is going to be helpful here. Do we have any brimonidine here? Could we put in another drop, please? Brimonidine is one of my favorite supplementary medications for any type of conjunctival or vascular corneal procedure. Because it really is extremely helpful.
So, as I mentioned before, sizing is very important. You can see the superior part of this cornea is quite clear. The inferior has some scarring. And centrally we’ll find out what’s going on. We can go ahead and prepare the donor tissue. We’re going to put a little corneal shield on here while we’re waiting.
And this is a fairly young patient. What factors do you look for in the corneal donor tissue with such a young patient who has vascularization and you want a good survival transfer of this graft?
Obviously it’s nice to — although the cornea donor study did show a trend, it didn’t show anything statistically significant, the age is kind of indirect factor in survival. So, you want ideally a younger donor that matches the patient. In general, for me, I like to be within ten years. The donor tissue to the host. So, ideally this patient would have a donor who is 40 years or younger. And, you know, an endothelial cell count, again, is something that’s relatively important.
You don’t have to have a very high cell count, but you need to have a healthy cell count. Probably, again, for a young patient like this, you would be looking at something around 2500 or more. And I also look at death to preservation time. I usually try to keep that under 12 hours if possible. But, again, these are trends and not statistically significant.
So, this is a vacuum trephine. And we’re just going to center the tissue here. And we do that by just moving the tissue around and rotating the base of the device to make sure that it’s in good position. And we’ll turn on the suction just to keep the graft from slipping. And this kind of turning technique of the trephine base is a very good way to make sure. Because, of course, the cornea is not perfectly round, it’s a little oval. We can go ahead and punch. And we slowly lift off the top. Just to make sure because sometimes the — everything comes off.
And, again, then we usually put a little bit of Optisol on the graft. You don’t want it to dry out. You don’t want to forget about it. So, the vacuum trephine works best when it’s wet. And what’s nice about the Brimonidine is that it tightens the conjunctiva and makes it much less likely to get sucked up into the vacuum trephine which can be quite annoying sometimes.
What we do here is we line up two inner barrels. Once the two inner barrels are lined up with this particular model, we go back four to six quarter turns. So, one, two, three, four, five, six. Each quarter turn is 50-75 microns with this particular model. Some go up to a hundred. And then what’s very important here is you’re applying the vacuum trephine, you want to make sure that the cornea is perpendicular to your microscope. That way you can see down the barrel. I’m rotating the eye so it’s lined up with the cornea.
Now, we’re going to line it up — we know where our geometric center it. We can decide if we to want go higher or lower. But I think it’s actually pretty good. And once it’s in place, we’re going to press down a little bit. Okay. And we’re going to let go quickly. We have suction. That’s great. Okay. Now we’re going to rotate quickly. One, two, three, four, five, six. That’s our six. One, two, three, four, five, six. I’m going to wait a minute here. He’s belling a little bit. I don’t want to manipulate the eye too much until he’s a little bit deeper.
Right. Is that just the patient’s sedation —
I think it was a little light.
One thing I do, which we have not done which we will do at the end of the case is we will give a block at the end of the case. Sometimes I give it at the beginning. So, I’m just waiting a moment here. We’ll wait until the eye rolls down a little bit. Usually if they’re belling, if we do too much manipulation, we can have the eye risk prolapse and other things like that. So, we’ll just wait until the patient is a little bit deeper.
Now, you’ll notice there’s a little bit of blood here as well. Since we are doing it, I’m going to ask Alisa to put another drop of brimonidine into the eye.
And you’re using the Brimonidine for a vasoconstrictor.
Yes. Exactly. It’s for vasoconstriction. So, that, really, again, helps control the bleeding. And works quite quickly. I’m very impressed with it. Some of these eyes that are very inflamed and congested, it’s better — it’s coming down. We can see the eye rolling down a little bit. Again, we don’t want to do too much. I think we can see where we perforated was up above here. Usually we use some viscoelastic, so we’ll put some healon in.
Now, remember, the patient is phakic at this point. We don’t really know what the lens status is. So we’re going to take a little peek here. And we’re going to take the scissors to the right and that will take Utrata forceps. And we’ll use the Utrata forceps to peel the iris off. And we have to be a little careful if you kind of are a little aggressive in removing the iris tissue, you can rip off the iris.
So, what I like to do here, we can evert the tissue. We can see the edge of the graft. And we can kind of try to pull it away. We try to preserve as much iris tissue as possible. You want to be a little careful here. But we’re looking reasonably good. There we go. Some BSS, please.
I think the lens looks pretty clear. It looks like the lens is pretty clear to me. You know, I can get a good read reflex. My feeling is less is more. I mean, the patient can, in theory, have cataract removal in fact future.
But given his age, you know, if he was 65, I might consider taking the lens. But at 28, he still has accommodative ability. If I think that there’s a chance that I can keep the lens, whether it’s for one year or for ten years, I think it’s worth doing. So I prefer to keep the lens if I think there’s a chance, in young patients, and I think we’re ready for the cornea.
I believe the patent spatula is from Dr. David Patent. This gets turned over on the surface. You can pick it up a different way. I like to kind of flip it over. So, first thing that look at is I look at if there’s any arcus.
And if there’s a large area of arcus, I always try to rotate it superiorly to hide it under the lid. I don’t — it’s pretty uniform here. There’s a little bit here. But I’m going to turn the graft this way for optimal setting. And then we’re ready to start suturing.
And this patient, what type of suture are you using?
Because of the vascularization, for sure there would only be interrupted sutures. And a non-vascularized patient you could consider the use of a combination or running suture. So, the nice thing about the Pollack is it doesn’t require a helper. And now we’re going to use those artful dots that I placed to help with placement of the tissue. And always the first few are a little tough because you want — it’s hard to get the tension, hard to get the position correct. And then sometimes, again, we do a two and one, or three, one, one. Usually the first few I did do a three, one, one.
And Dr. Pineda, do you like to do alternating? So you put this stitch and then 180?
And do the counter-stitch?
Correct. So, again, these first four are usually the most challenging because you have to — you don’t really have a stable anterior chamber. So, now that these first few are in, we’re going to go to a two, one, one. Now, you do have to tie it a little tighter, the first few. It’s a little more difficult to sew in a phakic eye. You have to be a little more careful, obviously, about the lens.
And Dr. Pineda?
One of the things you said and I think would be worth reiterating is that you chose interrupted suturing, why?
Interrupted sutures, you know, they could be the standard for all your cases if you wanted it to be. But we use interrupted sutures here because of the vascularization. We have much greater ability to do selective suture removal in the post operative care. A running suture, unfortunately, requires that you be able to keep the running suture in for, you know, three to six months. And that may not be possible with a running suture in a vascularized cornea. So, usually vascularization leads to looser sutures in the post-operative period and higher chance of rejection.
And then, Roberto, you mentioned something very interesting about the use of vascularized graphs. The use of Avastin or anti-VEGF agents. What’s your experience or how do you do that? And what determines that?
Yeah. Sometimes we give it ahead of time. Before we do the surgery. Like, by two weeks. And other times we — we will do it afterwards. And I usually give it sub-con, at the limbus. I usually do it right in the office at the slit lamp. You know, it works very well in helping to control, particularly in the post-operative period the kind of progression or worsening of vascularization in the post-operative period because of the inflammation. And then to augment that, you know, we used steroids a little more frequently in the first week or so to reduce the inflammation as much as possible.
But there’s been some nice studies showing the infiltrate of leukocytes within hours after a graft. And things that, you know, those blood vessels bring in all those leukocytes. So, having those under control are nice in the post-operative period.
And then speaking of the post-op period, can you tell us, with this patient, what would be the post-op meds and how often you would see them in clinic?
Typical evaluation. You see them at post-operative day one. Usually we start with an antibiotic. Could be many had different types. But usually four times a day for the first week. And then usually steroid drops. I personally like to use eight times a day for the first week and then go down either to six or four, based on how the patient’s doing. The other important parts of the post-operative management are the interocular pressure. The high pressure is bad for the endothelial cells. So, a lot of times these patients can have pressure spikes. We use a lot of viscoelastic. You might be doing sneaky analysis, things that release pigment into the angle. So IOP spikes are common.
I typically will give all my post-op patients Diamox post-operatively to take to help reduce the IOP spike. And the second thing that’s very important is to manage the epithelial defect. So all the grafts, most of them the epithelium sloughs off right away. They have a 100% epithelial defect in many cases. And that needs to be managed. My expectation is that by one week the epithelium should be 50% healed at a minimum. If it’s not healed 50%, you have to do something to promote that. Which might involve a — placing a contact lens. It might involve a tarsorrhaphy. If the patient has a neurotrophic cornea. So, there’s a lot of things that you need to do to manage that.
So, I, essentially, if someone has a chronic epithelial defect, I see the patient every week until their epithelium is healed. So, just all the I would say is when you’re doing the surgery here, you want to make sure you have a nice formed anterior chamber when you have your eight sutures in place. I typically like to bury the eight suture when is I’m done before proceeding to the next eight. I think you — gives you much better idea of the kind of wound symmetry and tightness. And I replace any they need to before proceeding to the next stage.So, two quick questions about sutures.
When would be the earliest you would remove them because of astigmatism?
Yes. So, this is, of course, a very good point. The basic rule with sutures is, in the very beginning, meaning the first two months, you do not take out sutures unless they are loose. A loose suture is a liability for the patient. They are at risk for infection or enhancing inflammation leading to possible rejection.
But usually the earliest — it’s a little dependent on age — but for the adult, six to eight weeks is the absolute earliest you would consider removing a suture unless it was loose or broken.
And if it is loose, when do you remove it?
So, I remove it as soon as I see it. And if it’s — even if it’s day one, if it’s very loose, I will remove it. But it probably would need to be replaced. So anything in the first week, sometimes you have to bring the patient back to the operating room or to a minor procedure room if the sutures are very loose.
Okay. You guys did a great demonstration. And I’m very pleased that the patient’s lens is clear.
I am too.

3D Version

December 2, 2017

Last Updated: October 31, 2022

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