Surgery: Simple Limbal Epithelial Transplantation (SLET)

This video demonstrates a simple limbal epithelial transplantation surgery in a patient who presented with corneal vascularization and pannus as a result of chemical injury. A limbal biopsy was taken from the normal contralateral eye of the patient and the affected eye was prepared for the transplant. The limbal biopsy was cut into pieces and was populated on the cornea of the affected eye which was covered with amniotic membrane using fibrin glue.

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


Dr. Roberto Pineda: For this young man, actually had a chemical injury to his left eye. And with, I believe, lye. That’s become vascularized with the pannus. And we’re going to be doing a procedure called a simple limb ball epithelial transplantation. Our first biopsy, one clock hour of limbal tissue from the patient’s right, normal eye. And transplant it to the left eye after we remove the pannus and place an amniotic membrane. And also be using fibrin glue in this case as well. Again, usually taken from the upper limbal area. Usually I just take a three by three millimeter area.
Can you tell us why you want to repopulate the contralateral eye with these limbal stem cells? What is that trying to achieve?
When you’re trying to reestablish the limbal stem cell population in the left eye which has been destroyed by the chemical injury. And by doing that we prevent kind of conjuntivalization of the cornea with vascularization which has happened on that left eye. So, basically, this is a simple way to reestablish that — those cells — which are located in the palisades of Vogt in the limbal area. Obviously, we don’t really want to cauterize this area. We don’t really want to affect the limbal stem cells.
When you harvest this tissue, is it important that you maintain the orientation of what is epithelial and —
Actually, unlike a conjunctival autograph, this does not require orientation. Which is very convenient.
What percentage, or what fraction of the full thickness of the cornea and limbus do you think —
I think no more than 50% is required. But I think you want to get like a third, ideally.
So, we just harvested this little area here.
And, again, there’s no need to re-approximate I proximate the conjunctiva, you harvested superiorly so it’s covered by the eyelid.
Right. I don’t typically use VICRYL sutures to close this, and there’s enough redundancy in the conj, it heals over very quickly. We don’t do anything special. We put a little ointment in at the end. But nothing else required.
We may have to lyse the symblepharon first before we replace the speculum. That’s going to be much better. We’re going to have a little stream of fluid here. So, one of the issues, of course, with these cases, there’s a lot of bleeding. Now we can put the lid speculum in. So, we’re going to do a 360-degree here. And, again, this tends to be a very bloody procedure.
Do you think as there is so much addition and assembly and all these things, we can do it like two or three passages before going for the stem cell graft like amniotic membrane patching or grafting. We could do that earlier and then we could reduce the inflammation?
Yes, yes. I think what you’re pointing out is very important. But in the acute phase, you know, when this patient had his injury, I really think that’s the time for intervention. You know, reducing inflammation, controlling symblepharon formation. All of this is very important. So, I think what you’re bringing up is a part of the kind of intervention you want to provide these patients with as early on as possible. And I think, unfortunately, you know, many of these patients don’t get that kind of aggressive treatment that’s needed early on with their disease.
My kind of motto is to be very aggressive with managing these patients with symblepharon, with lysis, with amniotic membrane, with vantage contact lenses. I mean, they still may end up with, you know, symblepharon formation and some vascularization, but, you know, if you can control it in the beginning, it’s going to be that much better when you have to go in to do the rehabilitation later. And, you know, that’s the part that is hard to deal with because it requires a lot of time and attention on the part of the ophthalmologist.
But you want to basically work your way around the limbus to find the limbus. I mean, some eyes, I’m sure you’ve all seen this where is pannus is so bad that you can’t even tell where the limbus is. I think here we can find that area but it takes a little time and effort. Then again, we’re not doing anything — I think this is a very important point. I’m not doing anything over the cornea except I just cut some adhesions. But I’m trying to just focus on kind of clearing out the sclera. Okay. I think we’re pretty good.
I don’t normally excise a lot of the conjunctiva. Some people do. Definitely no consensus on that. But just kind of leave the conj recessed because we’re going to cover it with the amniotic membrane. And again, you know, I’ve not used any cautery. I try to avoid cautery because it just creates inflammation.
So, we’ll put a little brimonidine on here and then we’ll just start removing this pannus.
So, two questions. When will you see maximal effect from that limbal stem cell transplant. And then, B, what would be the earliest you would consider a PK in follow-up?
So, one of the great things about this procedure is that it tends to just get better and better over time. So, if you’ll get someone at six months, one year, two years, five years, things just continue to improve. I don’t think anyone really knows the maximal effect, but for in terms of a secondary surgery, most people would consider at the earliest doing something six months after this procedure to preferably waiting a year after this procedure before doing any additional surgery.
So, I’m trying to find the — kind of the best place to enter here. Let’s see if we’re in the right spot. So, sometimes it’s a little hard to tell. I don’t think we’re quite deep enough.
So, this is the patient who had the chemical injury with alkaline like lye?
Yes. This is a lye injury.
That is correct.
What if — it was a patient of — or Stevens-Johnson syndrome?
I don’t think you would do SLET in those cases because they’re usually bilateral cases.
And I, of course, these are patients we all want to desperately help.
So you prefer amniotic membrane patch for Stevens-Johnson syndrome in the acute case?
Yes, yes. It’s really helpful for preventing symblepharon and also reducing inflammation.
Well, I mean, how many days? Like within one week or something?
Every week replace — it’s going to melt. It’s going to melt very quickly. So every week you keep replacing, replacing, replaces.
Until their disease starts to quiet down. Could be a little challenging. I was trying to make a few incisions here to see if there was another layer interface. But I don’t think there is. What we don’t want to do is we do not want to perforate. Because that would require tissue. So, I think the emphasis on diseases like Stevens-Johnson need to be in the acute care of these patients. And that really means the hospitals have to have good communication with the ophthalmologist so that there can be aggressive in that early acute phase. When there is actually something we can do for these patients and not in the end stage where there’s very little we can offer these patients.
I think this is what we’re going to have to deal with here. And, you know, not all cases do the corneas completely clear. What we’re trying to do is just reestablish the limbal stem cell population so that we can do a PK later on. So, this patient might need a penetrating keratoplasty at a later date.
So, now we’re going to take the amniotic membrane.
Is it a double layer amniotic membrane?
It is a thick version of a dehydrated amniotic membrane, so it’s much thicker than the standard dry. It’s like double the thickness.
Are you using fibrin glue?
Yeah. We will use fibrin glue. So, we’re just preparing the fibrin glue here. So — but, yeah, you can use certainly VICRYL to secure anything that you’re not comfortable with. Yeah. One time when doing one of these cases I did actually perforate the cornea which ended up — we ended up needing to do a corneal transplant for the patient. Because it was so thin. So, sometimes these can be very deep and they can be very — even if you find the interface, they can be so thin. Now we’ll take the specimen, our biopsy.
So, this ideally we cut up into several pieces. Probably eight to ten to spread on the surface. Once you have your pieces you can kind of spread them around the periphery. And you can cut up any ones you feel are too big or too bulky.
So, basically I put fibrin glue on this to hold the pieces in place. And that’s it. Just going to let this sit here for a little bit. This is not the prettiest procedure, and it doesn’t look good when you finish normally. Unless you get that nice clean interface. Sometimes you remove that pannus and it’s kind of crystal clear underneath and that’s a really nice feeling.
So I just want to make sure that you don’t lose your tissue. So, again, we’re just trying to make sure the glue is not sticking to everything, which it usually does. Hold on —
So, for how long the contact lens will be there?
The contact lens will stay there until the surface re-epithelializes. So, that’s usually about two weeks. So, usually this is a very satisfying surgery because it’s a little bit kind of miraculous surgery because you’re taking a eye that really looks relatively hopeless and, you know, providing significant improvement in vision.

3D Version

December 20, 2017

Last Updated: October 31, 2022

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