This is a patient who had undergone prior congenital cataract surgery, he presented with corneal decompensation and an anterior chamber IOL . Dr. Mannis performed a penetrating keratoplasty procedure, removed the existing IOL and implanted a new IOL in the sulcus. Then an iridoplasty was done. Dr. Mannis also explained in detail about his suturing techniques while suturing the cornea.
Surgeon: Dr. Mark Mannis, University of California Davis
DR MANNIS: And our plan for this procedure is to remove the edematous cornea, fixate the lens, and then do a corneal transplant. This is a scleral expansion ring, called a Flieringa ring, and its purpose is to prevent the eye from collapsing when we open the cornea.
>> So, Dr. Mannis, in which cases do you use the ring?
DR MANNIS: We use the Flieringa ring in all children and in adults who are aphakic or in triple procedures, in which we are removing the support of the lens. In an adult phakic patient, such as someone with keratoconus, or in a patient with a pseudophakic, when we are not planning to do any manipulation, the ring is not necessary. The ring gives the surgeon a great deal more control over the eye, once the cornea is off.
>> So keep one on longer, and you cut one? So you keep it to suspend the eye, in case you need —
DR MANNIS: Exactly. We basically will have four separate sutures. I then clip these to the drape, and that lifts the eye, taking all the pressure off the eye. Also, I use a simple wire speculum, which is a lifting speculum, rather than a speculum that presses downward. So this one did not actually pick up sclera, so I’m going to replace it. It’s very important, when putting on the ring, not to tie the sutures too tightly, because you can induce a large amount of astigmatism with the ring, if you’re not careful. You simply want to have the suture snug around the ring, without pulling it all on the conjunctiva. Okay. So now our operative field is ready. This really prepares it so that we have plenty of control. The first thing we will do is mark the central axis of the cornea. So I would like a 7-millimeter Barron and a 7.25 millimeter Weck. So I’m going to oversize the donor by a 0.25 diopter. That essentially gives me an even fit. I’ll show you: This is the diameter of the cornea, which I’m showing you now. And that’s about about 11 millimeters, 11.5 millimeters. So that’s a normal-sized cornea. You want the size of the graft — so that the sutures stay in avascular tissue. That prevents vascularization of the graft. Oversizing by 7.25, since we’re doing a posterior cut, allows you to close the wound with a minimum probability of leaks, and without inducing myopia. Okay. The donor in this case is a 60-year-old, with a cell count of slightly over 3,000 cells per millimeter squared. It has been preserved in Optisol media, which will keep it alive usually for a period of about 10 days. Beautiful piece of donor material. Okay. So we’re gonna open the eye now, and we may or may not need the vitrectomy. I will need some Miochol at the beginning, to bring the iris down. And then we’ll decide how we’re going to do the fixation. So we’ll need the prolene suture ready. So this is the Hessburg-Barron trephine. It’s a 7-millimeter trephine, and it’s a suction device, which allows us very controlled entry into the anterior chamber. Each quarter turn of the trephine is 66 microns. So each quarter turn is 66 microns. One, two, three, four. That’ll take us to the corneal surface. Five, six, seven, eight. That’s 250 microns into the cornea. Since it’s so edematous, I’m going to take two more. One, two. So that’s about 450 microns into the cornea. So the unknown factor in this case is that we don’t exactly know how well or where the intraocular lens is fixated. This is the highest risk point in a keratoplasty, because it is at this point that sudden changes can take place, particularly with regard to the fluid dynamics in the retina. So it’s very possible at this point to get a choroidal hemorrhage. So I’m now going to dry the lens, so that I can get an idea of where the various components of the lens are. You can see that this lens is very loose. So I’m just going to try and figure out here exactly where the lens components are. So this is a very old style. This has to be removed. Fortunately there’s enough capsule that they’ll be able to put the MZ70 in its place.
>> So this is a Bausch and Lomb Adapt AO?
DR MANNIS: Yeah. Actually, I haven’t seen one of those in many years. So I’m gonna put in some Miochol, just to see where the iris comes. As you can see, the iris is not really moving.
>> This is a PMMA lens? 7 millimeters diameter of the optic?
DR MANNIS: Yes, it’s a one-piece lens.
>> One-piece lens.
DR MANNIS: That’s now in the sulcus. And it’s firm there. So I don’t need to suture the lens, but I am gonna put a suture in the iris.
>> They were asking: What if during the first phase, when we’re cutting the cornea of the recipient, and we see vitreous in the anterior chamber? Then what should we do about that?
DR MANNIS: In that situation, I would do a transpupillary anterior vitrectomy. You do a dry vitrectomy, with no infusion. Since the vitreous face looked like it was intact, I decided not to do vitrectomy. If there had been vitreous in front of the iris, I would have proceeded with a vitrectomy before putting the lens in.
>> So this is one of the advantages, Dr. Mannis, of having an open sky — the iridoplasty and lens fixation can be done sometimes easier than —
DR MANNIS: Exactly. I’m gonna try one more time. If I can’t get this closed safely, we’ll leave it open. So now we have a stable intraocular lens, and although the pupil is not beautiful, he’s got a good optical axis, so there’s no need to try and repair that upper half. I’m now covering this with viscoelastic, and we’ll be ready to start the placement of the corneal graft. So I’m now placing the cardinal sutures. The Polack forceps, which you see here, is used only for the first suture in a keratoplasty. And this is the first of the four sutures which are the cardinal sutures, which fixate the graft in position. I use a slipknot, which is very useful. As opposed to 3-1-1. This is a knot done in opposite directions, and it gives you extreme control over the tension. So there’s my — I establish my tension. Once I establish the tension, I turn the knot 90 degrees, and that locks it. In answer to your question about power calculation, over time the corneal surgeon begins to get an idea of what his average curvature outcome is. And I know that most of the time, I have about 45 diopters of curvature. So knowing that I usually have about a 45-diopter outcome, what I do is I get the axial length, I put in the corneal curvature of 45, even though it’s theoretical, and based on that, I choose the intraocular lens. And admittedly, it is not precise. But it’s relatively effective, in terms of accuracy. So the second of the cardinal sutures is not the most difficult, but it’s the most important. Because it will now fixate the graft left to right. So the goal here is just to get the tissue to appose. You don’t want to get any tissue compression. Because that will induce astigmatism.
>> So how deep a stitch, Dr. Mannis, you aim for?
DR MANNIS: Well, you know, different corneal surgeons have different philosophies about depth. I generally aim for a pre-Descemet’s suture, generally of the same length on either side of the wound. However, particularly in cases of keratoconus, I’m very comfortable with full-thickness corneal sutures.
>> They are asking: Why not running suture in this patient?
DR MANNIS: Okay. It’s a very good question. Running sutures are used in two situations. Generally we don’t use a running suture ever in pediatric cases, and we do use them in avascular corneas, such as keratoconus. It would have been very suitable to use a combined running and interrupted suture here, but I think for simplicity’s sake, we decided just to go ahead with interrupted sutures. But this would have been very suitable to do a running suture. So I don’t know if you can see in the screen, but I’m putting the suture in right under the forceps. And I’m aiming to come out right in front of Descemet’s membrane.
>> So the other question, Dr. Mannis: How soon after the surgery do you remove stitches, and is it different in children?
DR MANNIS: Generally, in an adult, I start taking sutures out at three months. And I make that decision based on the appearance of the wound and the degree of astigmatism. So I’ll do corneal topography, and then use the topography as a guide to which sutures need to come out. Generally I don’t take any two adjacent sutures out at one time. Now, that’s in the adult. In the child, generally sutures are completely out by 6 to 8 weeks. So now we have half of the sutures in. I’m gonna put a little more viscoelastic in the anterior chamber. We can see here that we have a very nice deep chamber. A little bit of iris adherence, temporally. But we are doing a Viscoat dissection, to keep the iris back. If the recipient cornea is highly vascularized, I put the knot in the donor. Because the knot recruits vessels. So in this case, we’re gonna bury these outside. There’s not a lot of vascularization. I want to keep the optical axis clear of sutures. Okay. Generally what you want to do is have about 2 millimeters. The suture will go in here. It’s slightly longer on the recipient side. So now we have all of our sutures in. We have a couple of things we need to do. We need to check and make sure there’s no significantly induced astigmatism. So I’m going to take the ring off. To remove any tension from the ring. All right. So now I’m just gonna go around and look at my wound, and I see there’s no spontaneous efflux of fluid. And as you can see, even putting fluid in the eye, there’s no leak. So what we’re doing now is doing sort of qualitative keratoscopy. And I’m not sure you can see it in the TV, but there’s a little bit of against-the-rule astigmatism. But he should be fine. So we conclude the procedure with injection of antibiotic and steroid, and the transplant is complete.
>> How do you irrigate the viscoelastics in the anterior chamber?
DR MANNIS: Actually, most of it has come out during the procedure. But I’ll show you how it’s done. So to do that, if there is residual viscoelastic, you can put in fluid on one side. And hold the wound open on the other side. And as you irrigate, viscoelastic will come out. But most of the viscoelastic is already out. So what I generally do at the end of the case is cover the cornea with Healon. That will protect the epithelium.