Lecture: Glaucoma – Trabeculectomy

This Live Lecture encompasses surgical principles and post operative care considerations of trabeculectomy.

Lecturer: Dr. Sandra Johnson


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DR SANDRA JOHNSON: Welcome. I’m happy you’re here. I’m gonna begin with my slide. You can see here I’m from the University of Virginia. That’s where Jefferson was from, when he worked on our Declaration of Independence. Very historical, mountainous place. Okay. When we think of trabeculectomy, as in how this evolved, you’ve got to think about the different ways we can filter fluid from outside the eye to… From inside the eye to another place. Because the trabecular meshwork isn’t working enough. We can do trabeculotomy, which is done here now, in adults, but has been traditionally the surgery for children. And that opens up the trabecular meshwork directly. There’s procedures where they work on non-penetrating deep sclerectomy, more common in Europe, where they have the filtration collecting in a scleral lake. And there is, of course, the trabeculectomy, where we’re shunting fluid from in the eye to the subconjunctival space. And there are tube shunts. Some of you may have experience with that. And that fluid goes back to more the posterior sub-Tenon’s space. You know, this is a schematic showing you the lens, the ciliary body, you can see the zonules, and we create a space right here at the limbus, a hole. Right? It’s usually a little bit of the sclera, a little bit of the iris. And now the fluid that can’t get into our trabecular meshwork very well can exit from the anterior chamber through this little hole we’ve created, into that sub-Tenon’s space. So, you know, when they first started developing the concept of a subconjunctival exit for the fluid, there was full thickness procedures. Where basically doctors just opened up the conjunctiva and made a hole into the anterior chamber, and closed the conjunctiva. And those worked very well. Our patients were blinded from the hypotony and complications of it. And then later, in about the ’70s, a doctor came up with the idea — well, let’s have some resistance to flow. And we did — the scleral flap was introduced, and the hole was made underneath the scleral flap. And then later in the ’80s, Dr. Hoskins came up with a concept: Well, what if we could release some of these sutures, if we don’t have enough flow? So we have the laser suture lysis. And releasable sutures, which are very good in your population. And then later, in about the ’80s and ’90s, we had antimetabolites introduced. First 5FU, and then mitomycin C, which helped inhibit the fibroblast reaction in healing. So that this surgery is more successful. When you want really low pressure, trabeculectomy is still the best option. We have multiple procedures in Europe, in Canada, in the United States, that are coming out, but they’re more for the earlier to moderate patient. And a lot of the patients still present with advanced disease, and need pressures kind of under 14. And so we — in some procedures, of course — still need supplemental medications, if you don’t drop them enough. So trabeculectomy is still a really good option, even though it’s got its pros and cons for getting pressures low. It’s also a good option for low tension glaucoma. If you have a patient who’s got glaucoma with a pressure of 18 and they need to be 10, because they’re progressing at 14, once they’re on medicines, you’re not gonna get them there with pretty much anything else. If you have the ability to know the central corneal thickness, that helps you to set the target IOP. You know, patients with a thin cornea can tolerate lower pressures without getting complications, compared to someone with a thicker corneal thickness. So let’s do a question. What is the AGIS IOP cutoff? If you reviewed your major clinical trials. For patients with advanced glaucoma? Is it the first choice? IOP over 18? Is it IOP from 14 to 18? Or is it IOP 14 or under? Or is it IOP below the teens? So go ahead and vote. And submit an answer for me, so I can see where we’re at. All right. Awesome. 75% of you knew that it is pressure of 14 and under. 25% picked the next category, which is 14 to 18, but actually in AGIS, that was the second curve, in the middle, where some of the patients did progress over… Oops, sorry. Some of the patients did progress in this category and this category. So AGIS, where they were very stable for seven years, was the IOP of 14 and under. All right? So congratulations to the majority of you. IOP below the teens — this is the rare patient that we need an episcleral venous pressure, that may be a low tension patient that’s progressing, despite a pressure of, say, 14 or 13, 12. And we have to make them even lower. So C is the correct answer. Very good group. All right. So when do we do surgery? You know, of course, in your countries, surgery is often a first line issue. And same thing here for people who come in with very advanced disease. And you kind of fall many times into this category, where you don’t have a lot of medical therapy to offer your patients. You know, and even when we do have medical therapy, and a patient can get multiple drops, we have issues with, you know, can they actually take the drops? Maybe they need help, and they don’t have help. Many patients cannot afford drops. There’s a lifestyle issue. Some people don’t have normal schedules from day to day, and it’s hard for them to incorporate drops. Some patients are allergic to drops. Even the preservatives — they can’t take any. And then of course we have many patients in this category, where they start losing vision. They think they have a cataract or something else more correctable, and they come in with very advanced disease, and we end up having to offer them early surgery. You know, many of you have seen these discs, I hope. You’re looking — that come in with advanced cupping. And advanced disease. And we need to take care of them. So when we choose to do surgery, and do a filter, of course, there are a couple surgeries, like I told you, like the non-penetrating deep sclerectomy and so forth. But really we’re often choosing between a trabeculectomy and maybe a tube implant, if they don’t have good conjunctiva or they’re very uveitic, and things like that. We can do a limbal-based surgery. That’s how originally I was taught. And it does need a little bit more help. You need more exposure. It can be a little bit harder to do when you’re by yourself, compared to a fornix-based. And fornix-based, I think, is pretty much becoming the more popular approach, because it’s easy to do. If a surgeon’s by themselves. It’s easy to get exposure. And so forth. A little bit more challenging to get a tight closure. We can do combines. So if there’s an issue with the lens, you know, a cataract or things of that sort, we can do a wound that incorporates a cataract wound, and our trabeculectomy wound. And then we have choices of the two antimetabolites. I hardly never do a case without antimetabolites. You have to be a really spunky 95-year-old or something for me to do a trabeculectomy without a 5FU or mitomycin C. And then of course, with the tubes, there’s various ones on the market. And some are marketed as valved, and most are marketed as not valved. So let’s go to the second question and just review tubes a little bit. As a side point. So if we… If you look at these four choices, which of the following is a valved glaucoma tube implant? Is it the Baerveldt? Is it the Auro Lab? Is it the Ahmed? Or is it none of the above? I’ll give you a few seconds to think about this and vote. All right. You guys are bright. Maybe you don’t need this lecture this morning. Or this afternoon. 100% of you are aware that the Ahmed is the valve glaucoma tube implant. Baerveldt and the Auro Lab, which is almost the same as the Baerveldt, have no valve within them. So you really have to take steps if you go into that surgery, that type of filtration surgery, to avoid immediate postop hypotony. You can get profound hypotony with these, even when you pull the stent. Ahmed, on the other hand, is quite a safe valve. A great one to start with. And maybe continue forever. I like it a lot myself. Because you don’t have very much hypotony when you place these. And so it’s a much safer valve and easier to learn. Okay. Combined. So I mentioned that sometimes we have to deal with cataract at the same time as the glaucoma. So sometimes the cataract pushes this decision. Right? So if a patient has a lot of cataract, and they have bad glaucoma, or they’re kind of maxed out on whatever medications they can take, then doing a combined may be in their best interest. So that you deal with the cataract, but you also protect the pressure by doing a trabeculectomy at the same time. The other choice sometimes — I had a case like this yesterday — is moderate glaucoma. So she had a big visual field defect experimental, and she was having cataract surgery, and she was on all the drops she could take under control, but then when we did her surgery, we take out the cataract, because glaucoma surgery often causes glaucoma to — excuse me — cataracts to progress. Right? So then the patient is dissatisfied. Their pressure’s better. But now they don’t see as well. Because the cataract is worse. And they don’t always understand that the cataract can be taken out at some other point. The narrow angle patients benefit well from cataract, because when you take out the cataract, you’re deep in the angle. If we do simply a trabeculectomy on someone with a narrow angle, often the inflammation postop and the shallowing — they will end up with synechiae in chronic angle closure now. And you made them worse if the trab fails. Their pressure is really high, because none of their own drains still exist. So if they’re very narrow, taking out the lens can be a good thing for the patient in opening up their angle. Pseudoexfoliation is similar to that too, because the lens epithelium is a major source of the pseudoexfoliation material that clogs up their drain. So when the pseudoexfoliation patient gets their lens out, eventually the drain works better. In my experience, it takes months to a year, and then I find that they’re on less medicines for IOP control, because we’ve gotten rid of some of that source of debris that’s going into their drain. So sometimes doing a lensectomy, when you’re gonna do trabeculectomy, is good for the patient. Okay. And then for medications, if you have a miotic, and I’m going to do a simple trabeculectomy, and I have some pilocarpine, I like to put that into the eye preoperatively. It helps you to make a prettier iridectomy, because the pupil is pulled down. Some people use topical antibiotics preoperatively. I don’t. I tend to just use the dilute Betadine on the surface of the eye, so that the conjunctival flora is greatly reduced. If you have it, subconjunctival steroid and antibiotic at the end of surgery is good. I usually combine some antibiotic with the steroid to help, because the steroid may increase the risk of infection. So I like to couple them. And that is a good thing for the first night. I keep up their medications preoperatively, because I think it’s safer to operate on an eye with less elevated pressure than elevated pressure so if they do their timolol or whatever drops they’re on, it’s better if their pressure is 30 and not 38. So unless it makes them super red, I like to have the medicines on board right up to the day before. It does give you a little bit of extra hypotony on the first day, because these are not totally washed out in 24 hours. You may have some lingering effects. But it does, I feel, make it safer intraoperatively, when you open the eye, because we all know that when we open the eye, the pressure goes down to about zero, and if their pressure is very high before we do that, we can get into trouble with choroidal effusion and hemorrhage. So I feel it’s safer to have the pressure lower. And probably many of you give them even some Diamox pre-op. I do that when the patient comes in with very high pressures, so that I don’t have as elevated of a pressure when I enter. And sometimes viscoelastic can be good. If I have somebody who’s got very high pressure, I will leave a little viscoelastic or use it during surgery. Make a paracentesis. It does make it a little bit more difficult when you’re testing your flap to know if you have it just right. Because the viscoelastic gives you — it comes out of the eye slower when you irrigate through your paracentesis. So it’s a little trickier sometimes to know — do you have just the right amount of tension on your sutures? But it can make surgery safer or make us feel better, because we’ve got something forming that chamber in an eye that’s got, say, pressures in the 40s. I think, for me, when I’m doing releasables, I like the square flap. This is a fornix-based. We open the conjunctiva. So that you have some space between the conjunctiva and the flap. I think you need at least about a millimeter — so when you close your conjunctiva, you’re not closing it right at the flap. And of course you need a little bit of room, so that you can see and do your flap. So generally, I try to make this wound 5 or 6 millimeters long, and then my flap is usually about 3 millimeters, and I don’t operate at 12:00, like is often advocated. I like to operate on one side or the other of 12:00. So for me, my trab flap would be right here. Or right here. So that the patient is left with a virgin — if I put my flap right here, I have a virgin quadrant right here, if they needed another trabeculectomy in several years. So if this failed, I have room to put in something else. And I haven’t scarred up everything so that they end up with a second surgery that’s gonna give them a limbal bleb — I mean a bleb within the fissure — is what I want to say. Because if you get a bleb at 3 and 9, it’s not very comfortable. So if you’re operating over here later, because that’s where their good conjunctiva is, it’s not as comfortable for the patient. So I start from the get-go and put a trab on one side or the other of 12:00. So that I have room for later. Because glaucoma is forever. It doesn’t necessarily get cured with one surgery. This here is what’s… Sorry. My slides are jumping ahead. This here depicts a limbal-based surgery. So here the incision is back behind the limbus. This is a little larger than I make it. Traditionally, you have an 8 millimeter wound, 8 millimeters back from the limbus. And you do your coag near the limbus. You can pull on the Tenon’s all you want for exposure. They’ve got a rectus sutures here. I usually use a corneal traction suture — is my favorite, rather than a rectus sutures. Because, of course, this goes through some conjunctiva. And then this, like I said, is a little larger than I like to do it. They went all the way over to where the superior rectus is, and I pretty much restrict my wound to the quadrant. So that I’m not near any muscle. Because if you touch anything here, it bleeds quite a bit. So I’ll make a little smaller incision in the quadrant, as far back as I can from the limbus, which does tend to be about 8 millimeters. Because then your nidus of healing up here is away from your flap. And then these can take early massage and things, because there’s a lot of Tenon’s back here, and you tend to have a very well supported wound. But for many surgeons, it’s more challenging and time-consuming than doing a fornix-based flap. Kelly punch. Not everyone has a Kelly punch. But of course, once we have our flap open, then we’re going to either cut out a little wedge of tissue — if I cut it out, I use my super blade, and cut on each side, with a sharp blade, and then use a little scissor to cut across and take out a block of tissue. And I try to — again, see how the Kelly punch is in the center. I try to leave about a millimeter on each side of my flap so I don’t have overfiltration. If you’re cutting out a block all the way to the edges of your flap, you’re gonna get an awful lot of flow. And that’s good in a reop, where you’re fighting scar tissue or something, but in an original surgery, on virgin tissue, you may want to just, you know, make it in the center, and leave a little bit of coverage on either side, so you don’t end up with a lot of flow at the base of your flap, a very limbal bleb, and potential for overfiltration. So really, you want your Kelly punch, or if you do the — cut out a block — to be very central. So that you don’t end up with problems with the flow and shallow chamber, if you can help it. For your patients, you know, a lot of African eyes and brown eyes have melanosis. And the melanosis is usually very pronounced at the limbus. So putting in sutures that we intend to cut with a laser, if you have an argon laser and the appropriate lens, can be fraught with problems, because the melanosis takes up the energy. And you can’t get the laser beam to cut the suture. A suture back here, the apex suture, very easy, usually, to cut, if you do laser suture lysis, because there’s less melanosis back here. So really, I advocate a square for you, with sutures on each side, that you can pull, as releasables. You know, if you’re gonna do suture lysis, you need your sutures to be long. So you have a chance to find them. So your apex suture should be as long as possible, if you have that technology. And then I like to always make — if I’m doing, say, a temporal, a superonasal bleb, then I want the suture towards the fissure to be tighter. So if this was nasal, we’d want this suture to be tighter, this one to be a little looser, because then we form that superior bleb. This one here at the apex, a little looser, so we have a posterior bleb. So how you put your sutures can direct the flow for postop. And we want — we don’t want them to get an uncomfortable bleb. And then, you know, it’s a good idea to have a paracentesis when you do the surgery. You’ve given them the miotic if you have it, so that the iris is covering the lens, in a phakic eye, and you can put your saline through your paracentesis, and test your flow. And try to leave the operating room where you think there’s a nice trickle coming from under your flap, with a well formed chamber. And you can put your cannula on the cornea, and indent the eye a little, and see that it’s a little bit soft. You don’t want a firm eye. That means that your sutures are too tight. You want to be able to put your saline in and see just a little trickle, probably from the side near 12:00 and posterior, and a good chamber with a little bit of a soft eye. So antimetabolites — we’ll go on there a minute. If you have 5FU, you can give them postoperative doses. In the 5FU study, they got up to 14 doses twice a day. They got a lot of 5FU. So you have room to give people 5FU. I usually give them 7.5 milligrams now, in a dose. You draw it right out of the bottle. The bottle comes 50 milligrams per mL. And you need a little TB-type syringe to pull out 0.1 or 0.15 CCs to inject with the small needle. And we usually inject away from the bleb, so that they get bleeding with the injection. It’s not gonna impair your bleb. And in rabbits, the 5FU injected 180 degrees away from the bleb circulates through the subconjunctival space. So it does get up to the bleb, and it’s probably in the tear film too. So you should inject this away from your bleb, unless it’s an awfully white eye. And you can supplement. You can do it in the first several weeks, if you need to, if a patient is healing too fast. You don’t think they’re taking their steroids. The eye is very red. You can give them supplemental 5FU to help encourage your bleb to be very functional. Intraoperatively, you can go to mitomycin. You’ve got to keep in mind that mitomycin, if it gets into the eye, it’s very toxic to the corneal endothelium. So that will kill those endothelial cells, and you’ll white out the cornea. So you have to be very careful with your mitomycin. Can’t be on any instruments or cannulas or anything you’re gonna introduce into the eye. What I use to touch the mitomycin goes off the table when I’m done with it. And I’m very careful with it. You can use — surgeons use anywhere from 0.2 to 0.5. I usually use 0.4. I very rarely use it for 5 minutes. I usually use it for a minute or two in a primary trab, depending on their risk factors. And 5 minutes would be more like a — trying to rescue a neovascular eye. They need an awful lot of antimetabolite to counteract their inflammation. And then you can use 5FU intraoperatively. And that’s — on pledgets, just like the mitomycin. You take it right out of the bottle at 50 milligrams per mL. And you have to wait 5 minutes with these sponges in the subconjunctival space. And you never want your antimetabolite to touch the conjunctival edge that you want to heal. So you need to keep it out of the wound or off the conjunctival edges, and keep it back underneath the sub-Tenons space. So here is an easy question. You’ve got a 50/50 chance of getting it right. Okay? And we’re gonna see which antimetabolite is cell cycle-specific. Is it your mitomycin or your 5FU? Oh, you need a little work on this question. So we have 40% who said mitomycin. And 60% that said 5FU. Okay? So… Let me give you a little info. So 60% of you, the majority, thankfully, who said 5FU, are correct. Because 5FU only kills the fibroblasts that are in the S phase. So it’s not as potent when you use it as an antimetabolite for surgery. As the mitomycin C. So the 5 fluorouracil — we use that for 5 minutes. There’s a clue that it’s not as potent. And it’s killing only a certain population of the fibroblasts. Mitomycin C is not cell cycle-specific. It kills the fibroblasts and it kills endothelial cells too. That’s part of the — maybe why we get more infections easier because of that. We have less blood vessels left in the bed and maybe in the conjunctiva. So mitomycin C is not cell cycle-specific. It’ll kill cells in any phases. And as I said, it can kill endothelial cells of the cornea, and when they used to use it as drops for pterygium, people had all kinds of problems. They had iritis, they had corneal melts, they had corectopia. It can be very toxic. There’s even a thought if we leave it too long on the sclera that we can — it can get penetrating into the ciliary body, and kill some of the ciliary epithelium. So mitomycin is not cell cycle-specific, and this is part of why it is more potent, but has more complications. All right. So who do I use 5FU on? I think 5FU is a good beginner drug. So if you’re starting to use antimetabolites, it’s a good start, because it’s less toxic. And as I said already, so it’s a little bit more forgiving when you’re getting a protocol going of making sure your staff handles the sponges correctly, making sure you find all your sponges. I dye my sponges purple. So if you have sterile markers, you can dye them purple. You can go on EyeTube, under my name, and there’s a little blurb that I made, a little video, on dyeing your sponges purple, so you can find them, so you don’t have a retained sponge. People who are very old do great with 5FU. I use it here for them. High myopes. High myopes are the patients who can get hypotony, maculopathy, quite easily. So if somebody is -8, -10, minus whatever, they are much more at risk for hypotony. And it may even be because mitomycin goes into the ciliary body and may be something to do with their scleral rigidity, because you all know they have very thin sclera. But 5FU can be a much safer drug for them. In my Caucasian patients, I tend to use the 0.2 milligrams per mL. For my African ancestry patients, I use 0.4. And whenever I do combineds, I use 0.4. Because there’s a little bit more inflammation, and their trabs are more apt to fail. So they get a higher dose. And my feeling too is, in the African population, you know, one of the doctors I worked with in Zambia — it seems that the combineds don’t do as well with the 5FU. And that those are probably eyes you also need to obtain mitomycin for your best results. I tend to put 1 minute per risk factor. So if I have somebody of African ancestry, they get a minute right away. If they’re young, they’re 40 years old, with bad glaucoma, they might get another minute. If they have a lot of inflammation history, they might get a minute. Although we have to be careful in uveitis, because these are also eyes where the uveitis eventually leads to hypotony, and so we have to be careful. I tend to put tubes, if I have one. Very advanced disease. We’re looking for a low pressure. They’re progressing at 14. Or we really would rather they be 10 than 14. And I may give them another minute. If I know they have a thin cornea, right, I can be a little bit more aggressive with my minute per risk factor. If I’m dealing with an eye that’s had a prior trab or some kind of reason their conjunctiva has been opened up, I might put another minute. You know, if somebody’s got very thin sclera, then I back off a little bit. If they’ve got nice healthy sclera, they can take a little bit more mitomycin. So really I will alter, sometimes, my dose. I may think… Oh, this is a person — I’m gonna give them 3 minutes. Because they’re 40 years old, they’re African, they have a cupped-out nerve. And then I get in there, and I find they have really thin sclera and stuff, I may give up a minute. So, you know, you can moderate your dose, depending on patient factors. People with prior scarring, if you’re going into an eye that failed a prior trab, these are eyes you may want to make a smaller trabeculectomy flap in. So if you have a 2 millimeter flap, and then the suture is gonna release, they’re gonna have a lot of flow. You’re barely covering that little sclerostomy. You’re almost making it a full thickness. Sometimes that’s what these people need, to be able to counteract their scarring. And as I said earlier, you can use postop 5FU, if you have it. You know, that is… Can supplement people’s postoperative care. Some of you may know of Peng Khaw. He is in England, and he did some nice work on wound healing after trabeculectomy. But he changed two things. So he changed how he made the incision. Limbal versus fornix. And at the same time, he changed how you administer your antimetabolite. And really, you can get a nice bleb like this, whether you do limbal or fornix-based. Because I believe it’s really how you apply your antimetabolite. You know, because if we get a bleb like this, okay, these are high risk blebs. These have the ring of steel, we call it, around it. Somebody opened up the eye — and this is how people used to do mitomycin and 5FU. They would open up the conjunctiva and treat right over where the flap is. And then what happens is only that area is absent of the fibroblasts. And then the fibroblasts, they grow and they multiply, and you create this scarring from the treated to the untreated area. And then the fluid is coming out of the anterior chamber, and then this gets more and more pressure on it, and becomes thinner and thinner, and then you end up with breakdown of the bleb. Hang on a minute. You end up with breakdown of this bleb. It becomes like a stretched balloon. And then they can get blebitis. And in 2003, he wrote a paper on this, and they did some type of review, showing the change in amount of leaks and blebitis. And blebitis, of course, can make endophthalmitis. So here’s an eye — European eye — that had a fornix-based bleb. And you can see how diffuse the bleb is. Because when I open up the conjunctiva, and see, I did not go at 12:00. I can do a trab over here later. This is untouched tissue. But when I went in and opened up the conjunctiva here, in front of where my iridectomy is, I took my Westcott scissors, and I undermined the tissue over here. I went underneath the Tenon’s and made a pocket. And then I could put my sponges up in the fornix, because I don’t mind — or excuse me — up in the quadrant. Because I don’t mind if I get flow that goes behind the eye or something. And I put the sponges along my superior limbus. Where I want the bleb to form. Right? And this bleb certainly went right where I treated. And you can see it’s a little bit avascular. But certainly nothing like the bad bleb Peng Khaw’s picture depicted, where it’s all avascular in one space. You know, I still have a little bit of blood vessels. Because I really treated a diffuse area, and not focally. And same thing here. So this gentleman — and you can see he’s African ancestry — brown eye, melanosis — he had a limbal-based trab. And again, I went — not at 12:00, but in the quadrant. He has a whole bunch of other nice tissue if this fails. And you can see he’s still got some of his native blood vessels. And you can hardly even tell there’s a bleb here by the slit lamp. But I can tell you he had a pressure of, like, 10. And so what happened is the same thing. I made my flap and all. And then before I finish the flap and into the eye, I apply the antimetabolite into a pocket that I created along the superior limbus. I put the sponges where I want the bleb to form, and then later I take them out and rinse. So that I can get a diffuse — low, diffuse bleb. They tend to be comfortable, and they tend to be safer for the long term, because we don’t have that focal filtration that’s gonna just get thinner and thinner and cause problems. And this suture — you know, I closed it with nylon. It’s collecting a little bit of mucus. He’s getting little loops. These I’ll just take out at the slit lamp, if it’s bothering the patient. Because I use nylon for these closures. And it can last a long time and get loose when the patient’s healed. So if he tells me he’s getting a lot of mucus, or maybe — people don’t usually feel this suture, because it’s way up under the lid, but if he was feeling it, whatever — I can trim these at the slit lamp and make him more comfortable. All right. Postop care. I believe in shielding. So patients go home, and I try to give them a shield to wear for a couple weeks, because — while their suture are healing. You know, you can get a wound leak if they push on their eye right when — you know, close to surgery, before everything is nice and tight. I tend to put them on an antibiotic for a week or two. Of course, they have to stay on an antibiotic, if they have a wound leak or a bandage contact lens. I really only tolerate leaks for about a week. If they come back and they’re still leaky, I will do a suture. Because leaks are the death of your bleb. You know, you’re gonna end up with — the conjunctiva is collapsing, it’s close to the episclera, and the patient will get adhesions, and you won’t form a nice bleb if you let a leak persist. And a lot of you in Africa keep your patients for several days in the hospital. It makes sense to bring them back to the theater and tighten up that wound before you let them go home. I use steroids based on anterior chamber inflammation. And how the conjunctiva looks. You know, we don’t want an injected conjunctiva. You know, we don’t want a lot of inflammation. So, you know, most patients are on 4 or 6 times a day to start. And then I taper them over a couple months. You know, they’ll go down to once a week. I’ll keep them on once a week for an extra month or so, so that we have a nice quiet eye, and we inhibit any inflammatory response. If they’re phakic, and you have cycloplegia, that can be good if they’re shallow. That can help deepen the chamber, so you protect the cornea, and you help them not to get a cataract. If they’re pseudophakic, they’re usually, to me, not as shallow as the phakic eyes, potentially. You know, and of course they can’t get a cataract. You’re more worried, maybe, about the cornea. And then I use this Carlo-Traverso maneuver, which I’ll show you a slide on, to make sure the bleb is functional and to break adhesions in the early postoperative period. Seidel test, if you have fluorescein strips, this is very good to check your bleb. This is a man I had years back, with a bad bleb. You can see he had that ring of steel. This is not an early bleb leak. This is a later bleb leak. The early bleb leaks are usually right along the limbus, where you closed. I mean, hopefully your technique is such that you don’t have buttonholes in the body of the bleb. But sometimes, as the bleb elevates, it’ll pull on your limbal sutures, and one of them leaks. Or a suture was cut too short, and it breaks, or something happens along your surgical wound, that you need to repair. You know, and then you do need to watch out for little leaks that you might get, that are buttonholes, but those are not as common as here. But the late leaks, if you get a ring of steel, are in the body of the bleb. So he’s got a really thin area here, and it’s breaking down. You know, and this bleb can be needled or something, to try to break this wall of steel. If it’s been there for a long time, though, it can be very, very fibrous and hard to penetrate. Bleb leaks — you know, some people treat them with aqueous suppressives. Like the former one I just showed you would be a good one. The late bleb leaks — this can be a good thing. Take some of the pressure off the inside of the bleb, and maybe the wall can heal. Early on, if you use these, you may let your bleb collapse, and you may lead to bleb failure. I give some of them an irritating antibiotic, like gentamicin. That’s more irritating than, say, using a fluoroquinolone. BCLS, if you have one. If you have — we have these daily contact lens samples and stuff that I’ll use, that usually will cover a limbal bleb well. Blood injection can work well for later. If you have a bleb leak on the edge of your bleb, if you put blood into the center of your bleb, the problem is they’ll get hyphema and blurry and things like that. So I tend to use this not for central leaks, but for peripheral leaks. Bleb needling — that can work very well, if you catch that ring of steel early. You know, surgical revision, sometimes, can work. You have to redose some 5FU and things, because these are people prone to scarring. Carlo Traverso. So he’s an Italian ophthalmologist. And this is a wonderful — one of the things I use a lot in my practice. And that is taking a Q-Tip or your finger — you have the patient look down, and you push with your finger, a little bit behind your flap. Just gentle. Because you don’t want to open up a limbal wound. Or your other wound. But you want to make sure your flap is not getting sticky and there’s good flow. And so you just put a little gentle pressure and let the bleb elevate for the patient. And I do this… Just about forever. When they come to see me, you know, down the road, I’ll push a little bit behind the bleb. Make sure it’s functioning. Make sure my bleb looks like it enlarges and that it’s still functioning well. So here’s a schematic. You know, this one is using a Q-Tip. Right? And so you’re pushing behind the edge of your flap. And by pushing down, see, you’re elevating the flap itself from its bed. So you’re making sure there’s no little adhesion here. When I push this down, if there’s a little adhesion forming, it’ll break. You know, and it’ll help keep the flow going through your bleb, and get established in that early postoperative period. And you can’t — you’ve got to be gentle. Because you don’t want to disrupt a wound. And this is the same idea. But you can — I use my finger a lot. I just have them look down and push. Right behind the flap. And that tends to help. In the early postop. Suture lysis. You know, there’s various lenses — there’s the original one Hoskins invented. There’s other ones that I like better, like the Ritch lens or the Mandelkorn. That gives you a lot of focal pressure. So if somebody has thick Tenon’s, you can get a really good look. And here’s a view of one. Cutting this stitch — probably not gonna do a lot, because it’s a little bit… It’s a little bit loose already. And you need an argon or a diode laser, because the green light wavelength will be absorbed by this black suture, and it’ll snap open. And in the African patients, an apex suture can be cut like this. Or sutures on the back end of a square. You know, where there’s not much melanosis. And here’s a schematic. So here’s the person’s flap. Here’s their iridectomy. They had their sclerostomy cut out. Again, I wouldn’t put my surgery at 12:00. I’d put it a little bit to one side. And they have these two sutures here that can be cut. This was a limbal-based surgery. And then here’s the big Hoskins lens, and it has the little focal bubble in it, to see the sutures well. And then if you had a Ritch lens, then you’re just looking right through this little focal area, and then you aim the laser, focus it right on the suture, and it breaks. And then you can get more flow. And then I put my releasables near the base. So if I have a square flap like this, in an African eye, then I have my releasable suture here, and a releasable here, and then either one suture or two sutures on the back, depending on the flow. And those are — if you have suture lysis — can be cut that way. And then the releasables, where you have the melanosis, can be pulled. Okay? So here’s an African patient. This is one of my patients, actually, a Nigerian immigrant, who’s been in the United States many years, with bad glaucoma. And this is early postop. You can see his bleb is pretty diffuse. You know, it’s still more vascular than it’s gonna be when he’s done his steroid. He actually has a pressure of about 7 to 10 now. He’s probably a year out. But the bleb is very diffuse. I don’t think I had to pull his releasables. I don’t remember exactly. You can see my closure. I tend to use nylon, because it’s very strong. I try to bury the sutures, so I usually have one suture on each side, where it’s not buried. And then this one I put right behind a little bit of conjunctiva, across, in front of my flap. And I don’t bury it, but I try to have it so it’s under a little roll of conj, so it’s more comfortable. And I should have cut this even a little shorter. And then he has a square flap that you cannot see. And then he has a releasable on each side. So if I never use these releasables, the way I place them, it’s not with a tail, but you have your intracorneal part. And then you take a little needle or something, and you elevate this, and break it. And then you take a forceps to pull it. And they’re hard to pull after a couple weeks. They’re really the best during the first two weeks. And when you place them, you try not to get Tenon’s in your suture. So that… Because if you’ve got tenon’s in your knot, they’re harder to pull. And then of course, as time goes on, and everything heals tighter, they’re harder to pull. But you have these for your first several weeks that you can help if your flap is tighter than you want, or the patient’s healing too fast. And I always pull the 1:00 closer to 12:00 first. Because I want my bleb to form going superior. If I pull this one first, I might get a big interpalpebral bleb, and I don’t want that. I wanna keep my bleb up here. So this is the one that I would preferentially pull first, to try to increase my bleb. If this patient is a really scarring patient, and I’m desperate, don’t worry — I’m gonna pull this one too. Oh, this is a little bit blurrier than I thought it would be. But I want you to take a look at this eye. Okay? This is a bleb that’s several weeks out. And I want you to kind of take a note of what’s going on here. Okay? So take a look at the picture. And then… Where is my… Hm. Okay. Here it is. So in that picture I just showed you, okay… Oh, I can only go forward. Okay. What predicts that this could be a failing bleb? Was it the height of the bleb? Was it the injection? Was it the corkscrew vessels? Or was it because we can’t see his flap or her flap through the conjunctiva? I’m telling you, you’re a very smart group. All right. If we go back to the picture, which it doesn’t want to do for me… Let’s see. If you imagine that picture, then in your mind’s eye, it’s really the corkscrew vessels. Which 75% of you chose. When you start seeing those big vessels that are all tortuous, and like a corkscrew, like we’re trying to open a bottle of wine, that configuration of vessels — even if the pressure is good — those portend bleb failure. Okay? Sometimes we don’t see the flap through the conjunctiva. But that can be because they have a really nice bleb. So we don’t worry too much about that. Although if you push with your laser suture lysis lens, for example, and you can’t see the flap when you compress, well, that could be a problem, that you’ve got really thick Tenon’s and a Tenon’s cyst or something of that sort. But really, when they come in, and they’ve got those really tortuous vessels, even if the pressure is still good, this person wants to go into the scarring phase. Because those big blood vessels’ purpose in life is to bring the mediators of healing. They’re bringing all kinds of growth factors and things to that bleb, to that wound we created in the operating room. And they’re trying to make the site heal. They think that mother nature didn’t put that flap there and cut that conjunctiva and do all the things that we did to the eye, and it wants to go into healing, and it’s bringing growth factors and trying to scar down that bleb. So at these times, I may do laser suture lysis or pull a releasable. Because I need to counteract the healing of the patient. And I’ll say… Because you know what? There’s been times I didn’t act, and they would come back in a week or two, and now instead of a pressure of 15, I’ve got a pressure of 30, and things are much more scarred up. So when I see those vessels, I pay attention. You can increase their steroid. Right? Try to combat with antiinflammatory. You can give them several doses of 5FU. You know, 5FU — I didn’t say earlier, but it’s corneal-epithelial toxic. So if you give people too much 5FU, they can’t see for a while, because they get toxicity to the corneal epithelium. And corneal epithelium regenerates and will eventually heal, but they get a very swirly pattern of the corneal epithelial cells, and they’re not normal for a while, and it makes the patient blurry. So I really will look at the cornea, when I’m giving a series of 5FU shots, and see how they’re doing. And I find that people can tolerate 3 to 5 doses, postop. You know, usually sparing the cornea. So if they come in, and I give them some, and then I see them several days later, and the cornea still looks good, I can give them some more. And I’ll titrate up, based on how the corneal epithelium looks. Because they get frustrated when they have that toxicity and they don’t see well. And it takes a long time, sometimes, for those corneal epithelial cells to kind of normalize and give the patient good vision. But when you see the corkscrew vessels, or you think your bleb is failing for another purpose — is very low, for example — then you’re gonna think about these maneuvers. 5FU — I already told you — you’re gonna have a little tiny syringe with 0.1 to 0.15 CCs. And you take it right out of the bottle. I tend to use my bottle, as long as it looks nice and clear, the medicine, clean the top with alcohol, you can use your bottle for a little bit. Massage — if you get a really low bleb, you can massage. And the teaching is: You do something to increase the bleb before you give them the 5FU. So they come in, their bleb is looking low, it’s looking red, you can massage it, do the Carlo Traverso, push from the bottom, cut sutures, pull sutures, make your bleb bigger, and then you can give them the 5FU. You’ve got to give them some topical anesthetic. I use 4% lidocaine on a Q-Tip. I usually give them some antibiotic or some Betadine to clean up the flora. And then usually I inject away from the bleb. I do it at the slit lamp. Tell the patient to look up. I usually give it in the inferior fornix. But you want the bleb enlarged, so when you give them the antimetabolite, you’re trying to maintain that larger bleb. Okay? Here’s needling. Sometimes persons will come in, and you can see that they’re getting fibrosis around the bleb. I did one of these Monday. You know, you may have to do yours in the operating room with some block. I give them the topical, and then I have some 1% preservative-free, that I inject as I’m going, and then you sweep side to side at the wall of the bleb. So that you can lyse those adhesions. You know, and reestablish the bleb. And they can end up, like my lady Tuesday, at a pressure of 23, and she’s only got one eye, and she’s in her 10-2 with an island of vision, and I went in with my little needle and lysed it, and her pressure is 4 now. It’s like she just had a trabeculectomy again. And it will creep back up. But she’ll probably go back to the 9 she was staying at for quite a while. But somehow, in between visits, she got sick. I hadn’t seen her. And her bleb started to scar down. And you give them, like I said, some antibiotic or Betadine before this, so that we don’t want to introduce germs. Small risk of infection, as always. I give them a phenylephrine if I have it, in my clinic, so that I don’t have as much risk of bleeding. Very important to not enter at the limbus, where we don’t have any Tenon’s. You want to enter away from the limbus, where there’s thick Tenon’s, to help you. Yeah. We don’t make trabs go inferior. Someone had a question. So… But sometimes the blebs will go all the way around. And you’ll have a low lying bleb for 270 or 360. Not much you can do about that. And they don’t tend to get infected. It’s usually the small eyes — they don’t have a big eye — and then there’s just not a lot of room, I guess, for the bleb to stay superior, and they end up with this low lying bleb kind of everywhere. Sometimes they’re a little dry eyed from that, because when they blink, if their conjunctiva is a little elevated everywhere, they won’t get good corneal coverage of their tears. And if they can get artificial tears, that will help them. But you don’t have to worry about infection if somebody’s bleb goes beyond superior. Really, if they’re getting germs up near the flap, that’s where they get their infections. But a low lying bleb I’ve never seen prone to infection, if it goes inferiorly. Let’s see if we get a few more slides. This I do in the operating room. You need a gonial lens. Sometimes the flap is what’s the problem. And you can take a cannula or an iris sweep, and cannulate your sclerostomy, literally, and elevate your bleb, and get reestablished flow, because the flap is what’s the problem. And these people have very loose conjunctiva. But this may be equipment that is not easily available to you. So let me just go through this. And then we will close up, I think. So, you know, you have your surgery. You do have to think about — are you doing a combined? Are you doing your fornix-based, limbal-based? What antimetabolites do you have? You’re gonna make a plan when you see the patient in clinic. For me, I have to look at the melanosis. Am I gonna do releasables? That kind of thing. Then you do your surgery. You have your intraoperative that we’ve talked about. When they come in one day, you’re gonna make sure your wound is good. You’re gonna judge the inflammation, so you can start your steroids. Gonna make sure there’s no leaks that need to be treated. Sorry. You’re going to decide if they need cycloplegia. Are they okay without it? So you’ve got some things to check. Then they’re gonna come back. You may see them more often, because you have the luxury of inpatient stay, or at least convenience for the patient. You know, I’ll see them maybe 5 to 7 days, postop, and see — do I have any new leak? Or any persistent leak that I need to suture? So I don’t like to leave leaks for very long. If they have a normal bleb, then I look. Do I need to pull a suture? Cut a suture? Do I need to do a little massage? Right? Because the bleb is red or looking low or the pressure is high. Do they need — especially a neovascular — do I need to give them a little 5FU or something, or more steroids, because they look too red? And then I see them, you know, once a week or so, for the next few weeks, looking for establishment of good flow and a good bleb. Looking — do they need suture lysis? Do they need 5FU? And so forth. And hopefully, you know, by 4 to 6 weeks, they have a well established bleb. All right. Any other questions, quickly, before we sign off? All right. You’ve been a very attentive audience. I hope you have a great day. Great afternoon.

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February 24, 2017

Last Updated: October 31, 2022

2 thoughts on “Lecture: Glaucoma – Trabeculectomy”

  1. Thanks, Dr. Johnson! I have seen that slide in your presentation where there was a leakage at the limbal edge of the bleb. in your experience, what is the best fasion for the closure of this defect with suture, if other means have failed? Much appreciated.

    • Any NnTo try and close a bleb leak at the limbus, necrotic tissue can be abraded to freshen the edge of the conj then suture through conj and sclera or limbus with 10-0 nylon parallel to the limbus to tack the edge of the conj down and compress the leak.


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