During this highly-interactive panel webinar, the full hour will be dedicated to discussing questions and patient cases that are relevant to the global ophthalmologist. All questions related to glaucoma are welcome. General and clinical questions sent in advance will be answered during the session.
- Dr. Malik Y. Kahook, Professor of Ophthalmology – University of Colorado, USA
- Dr. Leonard K. Seibold, Associate Professor of Ophthalmology – University of Colorado, USA
- Dr. Arsham Sheybani, Assistant Professor of Ophthalmology – Washington University, St. Louis, USA
DR SHEYBANI: I think this is a great case — especially when you handled it initially — when you have a patient with secondary open-angle glaucoma, I really worry about chronic hypotony, so I would start with an angle procedure. Since the needling failed once, I might do it again. I think between that or a non-valved tube shunt might be my next best scenario, and later we can kind of talk about the utility of doing a second trab versus not.
DR SEIBOLD: Yeah, and that’s a good feed into the next question. I’ll get to what I did here in a second. So the follow-up question would be: Just trying to make sure you can see that… What was one of the major conclusions from the tube versus trabeculectomy trial, or the TVT trial. This was the initial TVT trial, not the current ongoing TVT trial. So these are eyes that had a prior failed surgery. And I’ll pause here for audience response. All right, very good. So the majority answers were correct. So the main findings, amongst many from the TVT trial, were that additional surgery was more common, compared to the tube group, And surgical success was higher. Remember, these were eyes that had prior surgery. The medication requirements were absolutely similar between the trab and tube group. So now we’ll move on to the video. I think I clicked through it a little too fast. But we decided to do a non-valved tube shunt device in this case. Again, with the first eye, we put in a valved device, which worked initially, but then the pressure became uncontrolled, and she needed a diode laser after that. So I wanted to, in her better seeing eye, try to avoid that, and see if we could get her pressure controlled with one surgery, and so we elected for a non-valved device. This is a Baerveldt shunt going in. My hope was that we would achieve a lower pressure without the need for additional surgery. So we’ll pick up the surgery right here. This is as the implant is going in. We’re placing this in the supratemporal quadrant. So we’ve already dissected the conjunctiva back. I have muscle hooks isolating the muscles, putting the plate in, once it’s fitting nicely between the muscles, we’re anchoring this, with the 9-0 nylon suture, we’ve already ligated the tube. Again with the non-valved device you want to make sure you ligate completely. Now, this is what you need to watch carefully, because it’s easy to miss. This is a trimming of the tube. So we’re placing this in the sulcus. We’re trying to do a posterior bevel. Which looks uneventful. It looks like a clean cut there. We then take a 23-gauge needle, starting 2 millimeters back, enter into the sulcus. I use viscoelastic here to deepen the sulcus once the needle is there. Then as we wipe away the viscoelastic, get ready to put the tube in, you see… Whoops. There’s an extra cut there. Now we have a tube that’s well too short. I’d like to go back maybe and just show you that the first time, when we cut the tube. So this is actually my fellow doing the case, but you can see as she lifts up the tube and she extends the scissors too far, so it cuts in the proximal end of the scissors and also in the distal end of the scissors. It wasn’t a complete cut, but it was probably 95%, and just the Weck-Cel going across the tube, moving away that viscoelastic, you’ll see right here, was enough to complete the amputation. So now we’ve got a tube that’s too short. We’re just wecking away blood, thinking, at this point. So we pull out the tube extender. This is a product from New World Medical, the only off the shelf tube extender I’m aware of. We cut the tube shorter to allow space to fit the tube extender over the cut end, and that’s what we’re feeding it to now. And you take a look here — but there’s a fairly bulky plate about 3 millimeters from the limbus, right up against that needle sclerotomy, which is gonna be a problem down the road, so instead we switch to an angio catheter, from the IV tubing that you use to start an IV. We just trim about a 3 millimeter segment, which fits very easily over the cut segment of the tube. You can see we slide it over here… And to secure that in place, we’re gonna take a 10-0 nylon suture, and pass directly through the middle of that angio catheter or IV tubing, through the tube and out the other side. And then we’ll tie that off to secure that in place. And then we’re gonna take the tube extender tubing. You can also use the initial cut tubing to feed into the other end of the angio catheter. And again, pass the 10-0 nylon through it to keep it from sliding in or out. So this is a nice way, if you didn’t have a tube extender available, to extend your tube. So once we trim it again, more carefully this time, we’re passing it through our sclerotomy, securing the tube with 7-0 vicryl into place, and then proceeding as normal with — this is a Tutoplast patch graft being placed. We’re using fibrin glue to secure the patch graft, as well as the conjunctiva.
DR KAHOOK: So Arsham, what do you think about the procedure that was performed? Would you do things differently? Do you agree with the choices that were made?
DR SHEYBANI: I think that’s exactly what I would do. Sometimes if you have a little bit more tube left, if it’s cut too short, depending on the device, you can consider releasing the sutures that are holding the plate in place and moving things anterior, so closer to the limbus. That’s one way. And I think this is kind of nice. And I don’t know if Leo mentioned it, but it’s generally a 22 gauge angio cath, and I think that technique is excellent.
DR KAHOOK: So when you guys are asking for the angio cath, it might not be something that many people have done. So how do you go about asking for the angio cath in the operating room? Where can people usually find it?
DR SEIBOLD: So in our OR, it’s usually in the anesthesia cart. They’re obviously the ones usually putting in the IV. So they have usually a couple of options, as far as different gauges of angio catheters. But Arsham made a good point that I think I failed to mention, was to use the 22 gauge angio cath. You can see how easily it fits over the tube. That’s another difficulty, I think, with the tube extender. Is that it’s a little more — it’s a tighter fit, so it’s harder to pass. The angio catheter fits easily. It’s easy to splice it.
DR KAHOOK: In a lot of parts in the world, using an angio cath would be more cost effective, instead of opening up another product. That’s another part of it. Just some basic questions about tube surgery in general — 250 versus 350, from a drainage standpoint, why would you use a 250 versus a 350 or vice versa?
DR SEIBOLD: That’s a good question. I use predominantly 250s. I think there’s a suggestion that a larger plate size can get you to a lower IOP, and in certain scenarios, if we’re really aiming for maybe a single digit pressure, or if we have a patient that I know can’t tolerate even any adjunctive medicines, I’ll go with a 350, but those are more uncommon, I would say. For the most part, IOP lowering… The only comparison trial that I’ve seen has been equivalent, with maybe more risk of complications such as diplopia with the 350 plate. So if they’re monocular, they need a low goal, and they can’t tolerate medicines, those are scenarios where I might go with the 350. Otherwise I predominantly use a 250.
DR KAHOOK: Arsham, what do you do?
DR SHEYBANI: I’m with Leo. I don’t think the plate size matters that much. The studies aren’t great. There are some that show that going from a 250 to a 350 has no beneficial effect for pressure. I use a lot of the Molteno 255. It’s very similar in size to the Ahmed valve. I don’t have to get under muscles, it’s more comfortable for patients, and we’re publishing results on that, compared to the Baerveldt. And one of the biggest things is that time of surgery is less, because we don’t have to isolate muscles as much, and put the plate under there.
DR KAHOOK: That was actually my next question for both of you, about hooking muscles. So do either of you hook muscles with an Ahmed valve?
DR SHEYBANI: I do not.
DR SEIBOLD: I’m usually operating with a fellow or someone who’s training. I like it just in the initial implantation, just to give me a reference point. We usually put in a traction suture, protecting the eye, and sometimes you can lose your place, as to whether or not you’re truly in the supratemporal quadrant. I had a case where I thought I was between muscles, and the plate was actually just slightly over the lateral rectus, and the patient developed diplopia. So I find it’s kind of nice to hook muscles just to give yourself a reference point. I don’t leave them in. I just try to identify them, and mark, and then make sure I can place them as best as possible.
DR KAHOOK: Yeah, with complex surgeries, when you get in there, the anatomy might be slightly different than what you expect. Especially with one or two previous trabeculectomies. I historically have not been hooking muscles routinely, but about a year and a half ago or so, I was operating outside of the US, and we ran into a lot of complex cases that made me switch my practice pattern, and that’s something to keep in mind, especially when you’re doing a lot of advanced surgical interventions on these patients. I have one last question that I want to ask both of you, before moving on to Arsham’s case. And it had to do with what we call the pilot incision or the needle tract for insertion of the tube. Some people use a 23 gauge needle, some use a 22, just depending on what you have available, but how far away from the limbus do you like to enter into sclera? Do you do it differently for different patients? What do you think about that? I’ll start with you, Leo.
DR SEIBOLD: It depends if you’re going in the anterior chamber versus the sulcus or pars plana, but for an anterior chamber tube, I’m starting probably about 1.5 millimeters back from the limbus. If we’re going in the sulcus, it’s probably more 2 to 2.5. I don’t routinely measure, and it kind of depends on the patient’s anatomy. If they have a really hyperdeep chamber, or the anatomy seems anomalous, and I want to go in the sulcus, I’ll go a little further back. But I use viscoelastic either way, and I think a key is to really inflate whatever plane you’re going into. If it’s anterior chamber, pushing the iris back. If you’re going into the sulcus, like in this video, inflating that sulcus, really pushing the iris up, and that gives you a little bit wider of a runway. Because it’s always a little bit of a guessing game, when you’re passing that needle.
DR KAHOOK: What do you do, Arsham?
DR SHEYBANI: I like a 22 gauge needle. I find it’s a little easier to slide the tube into that area. It’s not as tight, but you still don’t get much peritubular flow. Since I use a larger needle gauge — a lot of people are using 23s — I’ll start 2 to 3 millimeters back for a longer tunnel, but there are issues with that. A longer tunnel sometimes places the tube a little anterior, near cornea, so you have to be careful to enter a little bit more posteriorly. And I’ll make it almost an angle, so it heads towards 12:00, if we can. But the main thing is looking at the sclera. If there’s a thin area, avoid it. You don’t want to overcauterize the area, so you don’t get some thinning or melt down the line. And if there’s a large emissarial vessel, I try to avoid that, because blood can even reflux back into the anterior chamber from that incision in the tube.
DR KAHOOK: Yeah, one thing I’ve noticed on some of my travels outside of the US, a 23 gauge isn’t always available. 22 gauges are much more commonly available in many ORs around the world. And even though publications might talk about 23, that 22 is still viable. I try to go 2 to 3 millimeters and try to angle into the anterior chamber, just for placement, but keep in mind a lot of areas around the world don’t have access to the Tutoplast or the tissue that we use, and so going back further, a longer tunnel, for more protection, is probably the way to go. A lot of surgeons have published on this. Felix Gil out of Mexico has published on going into the anterior chamber from a much longer tunnel. So it really depends where you are, and what you have access to. So really good discussion, really good case. Leo, I like how you mentioned that it was your fellow who did the case. That’s always good to know. But we learned a lot. We learned a lot from that case. But also from just a general discussion around tubes, and maybe now we can go to Arsham’s case? Present that, and we’ll do the same thing with the same exact format? So Arsham, take it away.
DR SHEYBANI: Perfect. So I want to talk about a patient with uveitic glaucoma and how we manage it. I think there are a lot of different options, and this case has a couple of different things that highlight where we can kind of branch off. You know, it was a 34-year-old male, so young. And they had worked him up for juvenile idiopathic arthritis, but he had no systemic signs or symptoms, and so this was an idiopathic… And I want to stress — non-granulomatous uveitis. He had been on steroids and was taking them to control the inflammation for over four years. He still has great vision. The pressure on presentation was 36 millimeters of mercury. And he was taking three different bottles, and did not tolerate brimonidine. On exam, the conjunctiva looked relatively healthy. And he had no cells in the anterior chamber. And he was pseudophakic. Looking at his cup to disc ratio, there was a significant amount of asymmetry, but very mild visual field changes. Regardless, we started him on acetazolamide and oral carbonic anhydrase inhibitor, and that brought him down a bit. So what surgical option is least appropriate in this case? So I think most of you picked diode cyclophotocoagulation as the least appropriate, followed by trabeculectomy and a partial goniotomy. What do you think, Leo, looking at the case of a uveitic, young…
DR SEIBOLD: Yeah, I think these are all viable options, and depending on what you have available, what procedures you’re typically doing, I think they all could be effective. I would agree with the audience in that… If I had to take one off, I would probably take the diode cyclophotocoagulation off. You have a young person with good vision, and really what looks to be an outflow problem. I think all the first four options are addressing that primary issue, and I think you’re gonna be more successful with one of the first five, I guess.
DR SHEYBANI: Yeah, I agree. And I think looking at it — even things like XEN, which might not be available everywhere, I don’t think that’s a great option in inflammatory glaucomas. Trabeculectomy has a higher failure rate. I think tube shunt is very reasonable to start with. But we’ll talk about the goniotomies. And the diode, again — young patient, prior uveitis, it could really flare the uveitis, and there’s no prior glaucoma procedure. Generally in a well seeing eye, diode we reserve after we’ve at least given them one new outflow procedure, and that’s generally either a tube or a filtration. Now, this is a secondary open-angle glaucoma. And I want to stress that, because these have at least an identifiable cause that’s elevating the pressure, and generally there’s some obstruction in the trabecular meshwork or just distal to that. And the visual field defect was actually mild in this patient. The one important factor when we start considering whether we’re going to use an ab interno goniotomy technique, whether that’s a partial goniotomy with the Kahook dual blade or using any type of suture or catheter for a larger goniotomy, you need to make sure that you think about the anticoagulation status. If they cannot come off of aspirin or coumadin or a platelet inhibitor, they are very high risk of having a hyphema that will not clear. We decided in this case, since it was a secondary glaucoma, in a young patient, that we went for a gonioscopy assisted transluminal trabeculotomy. I think there are people who would even do a partial goniotomy in this case. We just felt that the pressure was so high on the medication classes that we opted to treat more of the angle, and we’ll talk about some of the downs and ups. This is the surgical video. We take a 5-0 prolene suture and use hot temp cautery to round the tip of the suture. That’s to prevent it from going into an area that you don’t want. You can start with a 19 gauge hypodermic needle. Anything that you can use with making just a goniotomy, essentially, but we’re looking to make a very small cleft, so we’re incising the trabecular meshwork, and you need about a millimeter or so of an incision. We’ll place this 5-0 prolene suture inside the eye. And you can use any type of microforceps, even a retina forceps, but you need to have the ability to place that suture inside the goniotomy that you created. And then it takes about maybe 40 of these small pushes to push this suture all the way around the eye. As you see here now, we see the blue has come around. So the Schlemm’s canal has been cannulated for 360 degrees. We now hold both ends of this suture, and as we pull, it will strip or cleave the trabecular meshwork off of the canal. It’s a fairly aggressive procedure, actually. And there is a higher risk of hyphema, as you can see. There’s a lot of bleeding in the eye. You want to make sure you clear the viscoelastic and the bleeding as much as you can. But the key step is: I leave viscoelastic, especially in these young cases — you’ll see here we’re leaving viscoelastic in the eye. Almost half of the eye is filled with viscoelastic. And then we want to elevate the pressure to about 25 to 30 millimeters of mercury, at the end of the case. And in this case, it was one of the early ones. We did not elevate the pressure. We just left viscoelastic. And look at what the eye looked like on the left side. This is the day of surgery. We checked the patient four hours after surgery, and there’s already a significant layered hyphema, despite leaving viscoelastic. And the key point here is: You need to raise the pressure at the end of these types of cases to prevent the blood from refluxing back in. Leaving the viscoelastic alone is not enough. But in the secondary open-angle glaucomas, after you work through the hyphema, as you can see, this patient is now a little over two years with pressures that really range — in that kind of mid teens range, and off of the medications. Now, some things to consider… If the hyphema is growing or the pressure is elevated, due to the large hyphema, that’s when we do go back to do an anterior chamber washout. The washout, I would say, occurs in about 5% of patients. We’re actually looking at our data now. The other thing — you don’t always cannulate the Schlemm’s canal for 360 degrees. There are moments when you hit obstructions in the canal. And we pull the suture back and it still rips a portion of the canal off, or the trabecular meshwork off, so be mindful that you won’t always get to 360 degrees. But the hyphema management is critical, and one of the things I want to talk about is what we do with the steroid drops. When you have an active hyphema or a clot, I will continue them on steroids, to prevent fibrin from forming. Once the clot turns into a microhyphema, and you just have red blood cells, I will actually start backing off on the steroids. I want the microcells to clear. I want to reduce the amount of pressure that can rise through a steroid response. But in these uveitic patients, we do want to taper the steroids a little bit more slowly. So looking at this, this gonioscopy assisted transluminal trabeculotomy, what I want to point out — Davinder and Ron Fellman really kind of pioneered this. The publication was a really great publication, and it really shows the power of this procedure. So if you look at primary open-angle glaucomas, at two years, there was an average pressure reduction of 9 millimeters of mercury, with one and a half medications reduced. That’s very significant. Especially when you consider that we’re not putting a drain or any external device in the eye. But where this procedure really shines, and we see this time and time again, are in secondary open-angle glaucomas. And so these patients actually had a much bigger pressure reduction with a larger decrease in medications. The other populations this really can have a pretty good effect are patients with more mild to moderate disease. The more advanced the disease, or the longer they’ve had the glaucoma, maybe it’s because the collector channels have now atrophied, or become smaller, but for whatever reason, the more advanced the glaucoma, the less of a pressure reduction you will get with this type of procedure. But things like juvenile open-angle glaucoma — even post-traumatic open-angle glaucoma — pigment dispersion glaucoma, pseudoexfoliation glaucoma, and uveitic glaucoma can respond remarkably well to this type of procedure. But the trade-off is the risk of complications, including large hyphemas. So I want to throw out another question. The pressure spikes that can occur after gonioscopy assisted transluminal trabeculotomy — they form from which of the following? Is it a hyphema, a blood clot, a steroid response, or all of the above? So I think the poll… This is a relatively straightforward question for many, but it’s exactly right. It can occur from any of these different things. Malik and Leo, do you guys have any other ideas, as far as things that can cause a pressure spike after these types of surgeries?
DR KAHOOK: What do you think, Leo?
DR SEIBOLD: The only thing I would say is… You know, if you actually have failure of the surgery, or if in a patient like this — if they were to become inflamed, you mentioned fibrin — if the cleft that you actually make starts to seal up, and essentially a failure of the surgery would be the other reason the pressure would start to spike, although that probably would be a more gradual thing… But that would be the only thing I would add.
DR SHEYBANI: I think that’s a great point. One of the things with a surgery like this is it doesn’t remove the trabecular meshwork. It strips it. The trabecular meshwork is still there. So it can flatten back against the canal, and in fact sometimes you can be worse off than when you started. Because now as the trabecular meshwork flaps back against it, it will actually scar against the collector channels, and the pressure can even be higher. So there’s obviously nothing perfect in glaucoma, but I think that’s a great point, is just looking at that. One thing that does help in these cases: When the pressure goes up after these procedures — pilocarpine, after these procedures, patients are exquisitely responsive. Maybe through two mechanisms. But one of them might be that you’re actually pulling the trabecular meshwork tissue back down and opening up the angle a little bit. I don’t have a lot of great evidence that that’s why they’re responsive, but pilocarpine can be pretty helpful in these cases.
DR KAHOOK: Just one quick thing to add to that, Arsham. You were talking about leaving the eye inflated, and that significant hyphema that we saw, even leaving some viscoelastic in. What type of viscoelastic do you leave in?
DR SHEYBANI: Great point. The viscoelastic I like is a dispersive viscoelastic. And I’ve actually found that if you really leave the pressure high, you can get away with using less viscoelastic. We started seeing these patients that same day of surgery because we were dealing with quite a bit of hyphemas, and so the way we sorted out how to manage that or prevent it was because we saw them within the first several hours and realized that most of the hyphemas were occurring almost immediately, within the first few hours after surgery. And if we left the pressure high, whether we used the viscoelastic or not, that seemed to correlate with less hyphemas in the immediate postoperative period. The only reason why I leave the viscoelastic is: As it hydrates, it maintains that higher pressure for a few more days. If you use a cohesive, you could have that lasting longer than what you want, but the dispersive viscoelastic hydrates within 24 hours, and so you’ll have some pressure maintenance for the first few days, until the medications are washed out. Which is another point. After a procedure like this, I stop all of the glaucoma drops. Any medication on board can actually really lead to larger hyphemas, as you lower the pressure.
DR KAHOOK: That’s great. Why don’t you finish up with your key points, and maybe we can talk about this a little bit more, with some of the choices that we had.
DR SHEYBANI: Yes, so the pressure spikes that we talked about — the hyphemas can certainly do it. And if you see bloodstaining, you really need to address that surgically and remove it. And you need to be careful. Sometimes the blood will actually spill into the posterior segment. We’ve had two patients who have needed pars plana vitrectomies. We’ll B-scan if we don’t have a good view back there, because if you just take them for an anterior chamber washout and they have a lot of blood in the posterior segment, their vision still will not recover and you’ll have quite a bit of spillover into the anterior segment. The clots — you can’t visualize them, but certainly if they have a large bleed and take a while to resolve that blood, clotting in the pathway can do it. But steroid response is one that we talk about, and we don’t know enough about it. A lot of the original studies looked at steroid response at the trabecular meshwork level. But even looking at anterior segment OCT, to determine how much of the angle is open after these procedures, even patients with gonioscopy verified openings, for 360 degrees, can still have steroid elevations, where when they’re put back on the steroids, the pressure will go back up. So there might be something more in the collector channels that’s occurring with the steroids. That being said, even uveitics that need chronic steroid treatment — I was a little cautious doing these procedures in them. What I liked was a patient who was eventually going to go off of steroids, but the pressure was high and we could address that surgically. But even patients who are going to need steroids long-term can still do well with these procedures. The thing to think about is this: These angle surgeries really can’t get you below episcleral venous pressures. And most of us find that the pressures wind up in the mid-teens in most cases, in the best case scenario. And if you do put them on medications, there are certain patients who can have reflux hyphemas. It’s pretty uncommon, but that is a possibility. So just things to kind of think about, when you’re following these patients, post-op.
DR KAHOOK: So one of the things that I started doing with goniotomy is — we’re typically combining it with cataract surgery. But even if we didn’t combine it, just at the end of the case leaving about a 10% fill of a dispersive viscoelastic, you can even go up to the angle and just inject directly to where you did the goniotomy. I haven’t seen post-op day one pressure spikes. If I’m using something like a Viscoat or any other dispersive, and it dramatically lowers the rate of that reflux blood staying in the anterior chamber after the day of surgery. So I think it’s something that people can get accustomed to. And one thing that maybe both of you can comment on briefly is just the use of the episcleral venous wave that you can see at the time of irrigation and aspiration when you’re clearing viscoelastic. Arsham, do you use that at all to gauge success of your procedure?
DR SHEYBANI: I look at it, but there’s not a lot we can do about it. There’s data that tells us the larger the wave, the better the pressure reduction.
DR KAHOOK: Can you explain what the wave is? Sorry, I should have asked you to do that. What are we talking about here?
DR SHEYBANI: After you do these procedures, you inflate or pressurize the eye with balanced salt solution. If you look at the episcleral veins, or essentially just looking at the conjunctiva, at the limbus, you will see a whitening that will occur when you raise the pressure. That’s from the balanced salt solution flowing through the collectors. When the viscoelastic is in there, I like to raise the pressure fairly high, 35 to 40 millimeters of mercury for a fairly short time, to force the viscoelastic into the collector channels. And unfortunately you can’t do anything about seeing the wave or not, but if you do see it, I think your risk for hyphema could be a little bit greater, because now you have a lot of collectors that you’ve unroofed, but then hopefully your pressures should be better too.
DR KAHOOK: What do you do, Leo? Do you use it routinely, when you’re operating, just to look for it, at least?
DR SEIBOLD: I do use it routinely. I haven’t found it to be terribly prognostic in determining what the effect is going to be in that particular patient. I’ve seen cases where they don’t have a wave but still have a good response, and vice versa. It’s certainly reassuring, showing that we did what we set out to do in unroofing the canal and gaining access to those collector channels, but I haven’t found it to be very predictive, as far as success. One other thing that I’ll add in, as far as the hyphema rate — I noticed you do this at the end of the case. Arsham, you use some glue to seal the wound. I think that’s another important point, is either suturing or gluing the wound. Getting back to that fact of keeping the eye pressurized to minimize any reflux of heme. And that’s another way — I think we assume our corneal wounds are watertight most of the time, but through your main one, at least, throwing just a 10-0 nylon through it, or using glue like Arsham did, is an important way to minimize the risk.
DR KAHOOK: Yeah, great cases today. A lot of teaching points. We had some questions that came in, so I’m gonna try to go over some of the questions for about ten minutes. To the audience that sent in the questions, we’re certainly not gonna get to many of the questions, just for time’s sake. But we’ll try and figure out some way to get some of the answers to you in written format if at all possible. The first question that I want to tackle is sort of in the periphery of the case that Leo was showing. General question about tubes. If you have overfiltration after putting in a Baerveldt, or even an Ahmed, Leo, how do you handle overfiltration, hypotony early after placing a tube? Let’s say your tie off or non-valved wasn’t at 100%, or you’re just getting overfiltration in general. What do you do?
DR SEIBOLD: I think you want to try to manage them conservatively in the office first off. But it depends on the scenario. If they’re numerically hypotonous but don’t have any symptoms, I try to manage that. A cycloplegic is a mainstay, just to prevent or improve on any anterior chamber shallowing they may have. I use atropine and usually dose it fairly frequently, about four times a day. I think there’s benefit to doing that over just once or twice a day. And if their chamber is mildly shallow, I’ll manage with medications only and waiting, because typically it will improve over time. If they have a flat chamber, if you’ve got lens, cornea touch, that prompts you to do something a little bit more urgent. In the clinic, I’ll refill with viscoelastic, and reform the chamber. In these patients, I’m always watching for choroidals too. You need to be watching the posterior segment in these patients. Especially high myopes, eyes that may be more prone to developing that, because that also guides me as well. If they have mild to moderate choroidals, we can continue to watch that. Once they start getting into the visual axis or if they become appositional, that forces your hand into doing something more aggressive. And so that would be one scenario. Or if our — despite repeated anterior chamber reformations and persistent hypotony, I think if you still are fighting with this, you need to go back and either religate your tube — sometimes the Ahmed valve can fail. I’ve seen that before. It’s certainly not common. But tying off an Ahmed and letting a capsule form over the next six weeks can remedy that well. With the Baerveldt, re-tying it off. Occasionally I’ve even placed a rip cord then, after the fact, and tied it off, so once that ligature dissolves, you have something filling the lumen to give you a little bit more flow limitation. So I think those are all options. And most drastically, if you try those, I think last case you just have to pull the tube and do something different. Arsham, what would you add to that?
DR SHEYBANI: Everything is on point. I look for leaks too. When the pressure is low, sometimes you have to push on the eye to have a leak form, and you can see them at the limbus, rarely, if they don’t epithelialize well. And then even check over the plate. We’ve had a case where there was a small buttonhole that was really hard to see, where the fluid was going over the plate. Or for a plate exposure. Even a small plate exposure, very posteriorly, if it erodes through conjunctiva, then you don’t form a capsule, and you can have hypotony from that as well.
DR KAHOOK: Yeah, I think one of the take-homes is what Leo mentioned early on. That it depends on sort of the level of how flat the chamber might be. If it’s overfiltration and the lens is touching the cornea, you’re certainly inflating, and you can do that at the slit lamp. But if you have room between the lens and the cornea, you might buy time with atropine and watchful waiting. So those are important things. And that’s something that those who are participating today can see next time they do a tube surgery. If you do enough surgery, you’re gonna see these things happening for sure. So Arsham, there’s a question about contraindications for GATT. What are some of the red flags where you would not do a GATT in that specific patient?
DR SHEYBANI: I think that’s a great question. Angle closure where you have not opened up the angle, just be prepared if they’re phakic there’s a lot of PAS that can form. Patients that cannot come off of their anticoagulation or are too high risk for bleeding, I do not do it then. And an advanced glaucoma patient — I have not had good personal success, and even in the literature it doesn’t work as well. But what’s interesting is: Even patients that have failed a tube shunt or a trabeculectomy, depending on their type of glaucoma, you can even consider this procedure in those patients.
DR KAHOOK: And Leo, who are you doing GATT in? What’s your strategy when it comes to using that procedure?
DR SEIBOLD: So I’m a new adopter, recent adopter to GATT. I’ve only done it in the last six months to a year, with really good outcomes. I tend to use it more particularly in the case that Arsham mentioned. Last week I did the second eye of a 40-year-old female with uveitic glaucoma, exactly like his case. Her first eye did so well, we just did the second one. Only a week out, but doing great. I’m choosing it more over a Kahook dual blade goniotomy or partial goniotomy in those eyes that have significant pressure elevation in the high 40s, despite maximum medical therapy, and I want to give them every opportunity to try to get to that low controlled pressure without needing a tube shunt or trab in a young patient like that. So really secondary glaucomas and young patients — like Arsham mentioned, those were the home runs that were hit in Davinder’s paper, and so that’s primarily where I’m using it. I’m not using it as a combo for POAG patient who has cataract. Those I prefer the Kahook dual blade goniotomy. I’m curious if, Arsham, because I know you do both — I’ve had good outcomes — I think any angle surgery in a secondary glaucoma can do really well, and I’ve had patients who were off medications just in a Kahook dual blade. Have you noticed in your experience better outcomes with the GATT procedure? We like to think that the GATT, opening more of the canal, is better, but maybe four or five clock hours is sufficient in some patients. I know we’ve found that opening more of the canal doesn’t always achieve a lower pressure. Anything you’ve noticed, Arsham, between the two?
DR SHEYBANI: Not that I can comparatively speak to. The only difference I can be pretty definitive about is the hyphema complication rate is much higher than GATT. It’s very unlikely unless you use the device in the wrong portion with the dual blade to get a hyphema that won’t resolve.
DR KAHOOK: That’s a huge take-home. Just to mention Ron Fellman and Davinder, who have educated all of us on the use of GATT. But that’s their concern as well. That the rate of hyphema is much higher. As Leo mentioned, in the laboratory, which doesn’t always translate directly to the operating room, when you go above 4 or 5 clock hours of treatment, we don’t see much IOP benefit. This is still evolving. I was just visiting Leo’s clinic last week, and he had that patient who did really well with it, with the combo and doing a full GATT. So we just need to look back at our results a little bit more over time and see if there’s a difference. There’s another question along these lines I wanted to ask you. This is from John. Would adrenaline stop bleeding? So if you’re in the operating room and you do see reflux that’s significant during a GATT procedure, what do you do to mitigate that, other than viscoelastic? Is there anything else that you do?
DR SHEYBANI: So I’m not convinced all the bleeding is actually coming from just the collectors. Some of it is so arterial-looking. The iris vessels or the leaflet vessels cross near that angle, and I think part of the reason why you don’t see this with a stripping goniotomy like the dual blade and you see it more with GATT is because there’s more tearing. I have a great picture showing iris ischemia, because that vessel was probably severed, and it was a patient with a really large hyphema. If you see bleeding in the anterior chamber, the number one thing is pressurization. And you can think of the Ps, in managing bleeding. Pressure, patience, prolene, prayer. But the big one in ophthalmology is pressure. So get the pressure elevated. It’ll be unlikely you’ll be able to cauterize anything, and I don’t know if a pharmaceutical would stop bleeding, because it has to constrict the vessel, wherever it’s coming from, and I just can’t speak to that. I don’t use it. I just pressurize.
DR KAHOOK: Anything to add to that, Leo?
DR SEIBOLD: Yeah, most of the bleeding is not necessarily from a severed vessel. Arsham gave an outlier case of having an angle vessel that sometimes occurs there, and that’s a different story. I think you might try it if it was more fast paced. But it’s really reflux bleeding from the venous plexus, so I think pressurization is the way to go. It’s not a severed vessel you can cauterize. It’s just a matter of pushing that blood back from the venous plexus and into the anterior chamber.
DR KAHOOK: This is a question I get frequently, and it’s worth emphasizing that fact. When we’re doing any angle procedure, whether it’s an implant or any type of incision or excision in the angle, you’re likely to get reflux during surgery, and to me, that’s actually a good sign. Your distal collector channels are open. And you can also get hyphemas, if you’re doing a 360 GATT, and you have significant hyphemas, as Arsham was showing. Sometimes you have to intervene. You have to take them back to the operating room. One very common question I get is about cautery. To go in and do cautery to the angle. And I think it’s really important to think about the anatomy of the angle at that point. If it’s coming from the collector channels, it doesn’t look arterial, cautery is not the answer. If you do that, you’re probably gonna cause more bleeding and more significant adverse events. So that’s something to keep in mind. But if it is arterial, and people have success doing the cautery, to me that is a torn iris, a torn vessel. Arsham, the case you mentioned with ischemia to the iris, that would be a good one to publish in some way, for us to learn from that, because I haven’t seen a case like that. We’re coming up towards the end of the time yet. We haven’t answered some of the questions. We’ll try to get to them somehow. But Leo, do you have any ideas, one or two thoughts about tubes in general? What do you teach your fellows, as a pearl from you?
DR SEIBOLD: I would say maybe a pearl we didn’t get into, and it could be an hour long discussion in itself, is which tube shunt you would use. I think the group had primarily picked a valved device over a non-valved device. We talked about the TVT trial. There are a couple of other prospective large randomized trials comparing a valved device in the Ahmed with a non-valved device in the Baerveldt. And there are a couple of scenarios where one favors the other. I know in those trials we achieved a lower pressure and less medication requirement with a non-valved device, whereas with the Ahmed valve, obviously you’re getting immediate pressure reduction, but you’re ending up at a little higher pressure, in comparison to a non-valved device. In my practice, I use both. I probably use them 50/50, and I think it’s nice to have them both. Because there are scenarios such as in neovascular glaucoma, uveitic glaucoma, someone with really high pressures, in the 50s, 60s, that we just can’t wait for a ligature to dissolve and open up in a non-valved device. Those are a great use for a valved device. For those patients who are normal tension glaucoma, who — I would more patients than I would like to, with advancing normal tension glaucoma — those I prefer using a non-valved device, because I don’t want their pressure settling out at 15 or 14. I need them to be closer to 10. And with this particular patient, we needed her as low as possible. She required a subsequent procedure, and I didn’t get into this, but she developed some edema after that. So there are pros and cons and benefits to each of them, but the downside of using a non-valved device obviously is not getting that immediate pressure reduction and also a higher risk of hypotony or diplopia. It’s risk versus reward. As your risk goes up, your reward for lower pressure also goes up, and just tailoring the risk to the patient, depending on disease severity and what their treatment goals are.
DR KAHOOK: Sorry. I was on mute there. Any quick thoughts, Arsham, as we finish up here?
DR SHEYBANI: Just consider the angle in a young patient, with an open-angle, if they’re phakic or pseudophakic, and patients with secondary glaucomas, especially in mild to moderate disease, it’s a powerful potential and fairly reasonable complication rates, that aren’t as high as when we filter.
DR KAHOOK: So as we’re talking about wrapping up here, I have construction workers trying to get into the house, knocking on the door and looking through the window and wondering why I’m not answering. They can wait just a minute here. So I want to thank you for taking the time. I’ve really enjoyed this format. I hope people who are watching and listening enjoyed the format. I would encourage anybody participating here that got in on line to let Orbis know if you enjoyed this format of more interactive, having more surgeons talk about things, and maybe we’ll plan for another one of these in the next few months, as Orbis desires. But again, to Arsham and to Leo, thank you very much for the time that you took. Lots of lessons. I’ll try to answer some of the other questions that came in, if possible, through a written format, and I wish you both a good day, and to everybody who participated, thank you, and hopefully we’ll see you again here when we do our next session. Thank you.
DR SHEYBANI: Thanks, Malik.
DR SEIBOLD: Thanks, everybody. Bye.
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August 23, 2019