Lecture: Pneumatic Retinopexy – Principles and Pearls

Pneumatic retinopexy is an office-based procedure for repair of selected rhegmatogenous retinal detachments. During this lecture, the indications, principles, technique and complications of pneumatic retinopexy will be discussed.

Lecturer: Dr. Caroline Baumal, Tufts University School of Medicine, New England Eye Center, Boston, USA


DR BAUMAL: Hello, everybody. I’m Caroline Baumal, and I’m at Tufts Medical Center in Boston. I’m an associate professor here. And today I’m going to be telling you about a procedure called pneumatic retinopexy, some tips and tricks. And this is a procedure that we’ve done — we do for retinal detachment repair. We’ve been having a lot of success with this procedure over many years. So I’m gonna just get started. So what is pneumatic retinopexy? We also call it PR in these slides. And basically it is an office-based procedure for rhegmatogenous retinal detachment repair. Pneumatic refers to injection of gas or air into the vitreous. That’s the pneumatic part. And retinopexy refers to forming a seal of the retina, and that is done by using cryotherapy, either before the gas injection, or using laser after gas injection has made the retina reattach. This procedure was described — popularized in 1985 by Hilton and Grizzard, and also Paul Tornambe has discussed this procedure quite a bit. And basically I like to think of it as very similar to like a scleral buckle procedure, but without having the scleral buckle. So it’s very similar, except we don’t put the extra supportive silicone band around the eye. And it probably accounts for about 10% to 15% of retinal detachment repairs done in the United States. So the classical candidate who’s good for pneumatic retinopexy is a patient with a single break or multiple breaks within one clock hour of the peripheral retina. Typically someone who has a break in the superior 8 clock hours, so between 8:00, going up superior to 4:00, a patient with clear media, so a patient without any vitreous haze, a patient who’s able to position so the gas bubble can push and close the break in the retina. A patient with mobile retina. So no PVR or scar tissue. And then there’s another terminology called extreme or non-traditional pneumatic retinopexy, and that kind of encompasses things that don’t fit into the classical criteria that I told you up above. So who is not a good candidate or should not have pneumatic retinopexy? That includes eyes with PVR, which is proliferative vitreoretinopathy or scar tissue on the retina. Eyes with an inferior break in the retina. Eyes with a giant retinal tear. Eyes with severe vitreous hemorrhage. And eyes with very large breaks in the retina. So what are some of the pros about pneumatic retinopexy? And I have a paper here that was in Ophthalmology, done by one of our fellows, Darin Goldman. So one of the pros is: The overall success rate with primary pneumatic retinopexy is about 80%+, for all comers. The eventual success rate, so if the pneumatic retinopexy fails and the patient ends up having another procedure, there’s about a 98% success rate. There are two things that really have been found to account for some of the cases of failure of pneumatic retinopexy to work, and that is having an inferior break, or having visible traction on the retinal break that’s causing the retinal detachment. And in this study done by Dr. Goldman, they looked at annual health care savings in the United States, and increasing use of pneumatic retinopexy would probably save about $30 million in the United States, by just increasing this one procedure. So what are some of the cons of pneumatic retinopexy? It is a little more time-consuming in some places in the United States to do an office-based procedure, and also a really complete retinal exam is required. There’s a learning curve to doing the steps in the procedure. You need to have certain office equipment. Either cryotherapy or a laser. Which usually is helpful to have an indirect laser. You need to have access to intravitreal gases in your office. It does take some experience to get familiar with this procedure. A little bit more follow-up is needed than with having a vitrectomy. It’s not effective for all types of retinal detachments. Since we inject a smaller gas bubble in the eye, very strict positioning is required for the first four to five days. And occasionally this procedure does not work, and patients might need to go on to have surgery. So this is a classic pneumatic retinopexy candidate. They have a single break. Actually, it’s a horseshoe tear, and it looks like there’s another little small break, but just right beside it, within one clock hour of the retina, they have a localized retinal detachment. The location of this tear in the retina accounts for this detachment. It makes sense based on Lincoffs rules. And the patient will be able to position with their head up or just a slight tilt, to be able to have the gas bubble tamponade this break. There’s no vitreous hemorrhage. There’s no PVR. There’s no traction. And the retina looks mobile. Okay? So this patient’s 20/25, with a macula-on detachment, and this could be fixed in your office procedure. And this patient did have a pneumatic retinopexy. We can see the result after three months later. The vision is 20/20, and you can see the area of the cryotherapy, which is… Right up here. Okay? So these patients are not pneumatic retinopexy candidates. And we can see, for example, this picture here on the top row — there’s some traction on the retina, and the retina looks stiff. Beside that, there’s another case with scar tissue, and then on the bottom row, there’s an area of traction around the arcades on the bottom left. In the middle bottom, there’s a picture with an inferior retinal break. And then over here, there’s another retinal break with traction. So these are patients with inferior breaks, immobile retina, and PVR. These are not pneumatic retinopexy candidates. It would not work. So there are three principles of pneumatic retinopexy for rhegmatogenous retinal detachment repair. And actually, these are the principles for all retinal detachment repair. But they’re very important for pneumatic retinopexy to work. The first principle is: Find all the breaks in the retina. The second principle is: Treat all the breaks in the retina. And then the third principle for retinal detachment repair is to support and seal all of the breaks. Okay? And the thing with pneumatic retinopexy is: Like, in vitrectomy, when we support all the breaks that we’ve sealed, patients have a 100%, almost 100% gas bubble in their eye. We almost completely fill their eye with gas. But in pneumatic retinopexy, we can only put a smaller amount of gas in the eye in the clinic. 0.3 CCs. 0.35 CCs. Because we’re not taking vitreous out. So we can only put a limited amount of gas in the eye. So we have to get a single gas bubble, and that is a really key point, to inject gas in the office, and be able to get a single gas bubble. Because it is much more effective to seal the break. And that’s why a single gas bubble and positioning are very, very important. So… Let’s start with the first principle of retinal detachment repair. And it’s very important for this procedure. We must find all the breaks. And so for that reason, a careful, complete dilated exam is important. And there’s a couple pearls that we could use for that. One, which I’m gonna have another slide to show you, is Lincoffs rules. And Dr. Lincoff made a system of rules to decide whether — and to help us determine where the breaks are, with certain configurations of retinal detachments. The second pearl is: Pseudophakic holes. And patients who have had cataract surgery often have very, very tiny little holes in the retina, that can be traditionally very difficult to see. And with scleral depression, it often looks like a little fine white line. So to be familiar that these holes in the retina in a pseudophakic might be very hard to see, and might not look like the typical hole, but almost like a white little line. The third thing to think about is: Let’s say you see a patient, and you cannot find a break. You have to consider: Is this truly a rhegmatogenous detachment? Could it be a detachment that’s exudative or tractional or secondary to, for example, a melanoma under the retina? Sometimes an ultrasound helps, if there’s any question of that. So you have to consider the features of retinal detachment. If it’s rhegmatogenous, we usually see corrugated inner retina. If it’s exudative, we see often shifting fluid or cells in the vitreous. So consider a B-scan if something doesn’t seem right to you. So I had mentioned Dr. Harvey Lincoff’s rules for retinal detachment — rhegmatogenous retinal detachment. And rhegmatogenous means a break in the retina. So we’re talking garden variety break in the retina. Retinal detachment. And his rules define the probability for locating a retinal break. And these are the three rules, summarized here. The first one is that if there is a superotemporal or nasal detachment, 98% of the time the primary break will lie within 1.5 clock hours of the highest border of the retinal detachment. Rule number two: If there’s a total or superior detachment that crosses the 12:00 meridian, 93% of the time the primary break is at 12:00 or in a triangle where the apex is at the ora, and the sides intersect the equator one hour to either side of 12:00. And the third rule is for inferior detachment. 95% of the time, the higher side of the retinal detachment will show on which side of the 6:00 meridian the inferior break lies. Okay? So these are really important rules to consider when you see a patient. And to make sure, like, when you see a break: Does that break make sense for the way the retinal detachment looks? Because if it doesn’t, you should look very closely for another break. And these rules are often found in textbooks from retinal detachment. So here’s a picture of a patient who came in with a very bullous mobile retinal detachment. You can tell from looking at this retina that it’s loose. That there’s no scar tissue. Where is the break? Well, based off Lincoffs rules, this break will be one and a half clock hours from the superior border of the retinal detachment. Okay? So very important. Find all breaks. And you can see for the top two images in this picture: Lincoffs rules apply. But if we look at the bottom two images, where the break is shown — okay, so on the bottom left, there’s a horseshoe tear here. That does not account for the appearance of the retinal detachment. And really, there should be a break up here. Okay? And same for this retinal detachment. This break does not account for the appearance of this detachment. So we have to find… Look for the unsuspected break. Because there will and should be one there. So on to principle number two. We have found all the breaks in the retina. Second thing we have to do is we have to treat all of the breaks. So for pneumatic retinopexy, there’s two options: Cryotherapy or laser. And there’s two ways to do the procedure. Either we do cryotherapy further and then inject the gas bubble, or sometimes people inject the gas bubble to flatten the retina and then bring the patient back a day or two later for laser treatment. In my experience, especially if you are new to this procedure, it is much easier to do the cryotherapy first, before injecting the gas bubble. Because it can be harder to laser breaks in the retina when there’s a gas bubble in the eye. But in many ways, we have to do what’s available for us. But I do think that, especially if you’re starting this procedure, it’s beneficial to start with cryotherapy to treat the breaks. Also, cryotherapy has uptake because breaks are in detached retina, and it’s also really important to look and see if there’s any breaks in the retina where the retina is attached, and also if there’s any lattice in attached retina. Lattice degeneration also needs to be treated. Okay? So there are some pearls for using cryotherapy. Those are: Do not overcryo. So when we put the probe on the sclera, around the break, I like to do it just ’til I see the whitening or the freezing of the retina, and then I take my foot off the pedal. And also, if there’s, for example, a tear, a horseshoe tear, we want to treat the edges of the break, but not the base of the break. Not the inside of the break. Because if we treat the base of the break too aggressively, RPE cells can come through the break and go into the vitreous cavity, which might be able to stimulate PVR. So whenever we treat a tear with cryo, we want to treat around the edges of the break, and we want to treat going anteriorly to the ora serrata if possible. Also, we want to treat lattice or any breaks in attached retina. And that you could do with laser beforehand, or you could just do it with the cryotherapy. It’s very important to hold the cryoprobe correctly. And what I like to do is I like to look around the eye and make sure that I have my cryoprobe in the right position, which would be about 6 to 8 millimeters behind the limbus. It’s very easy to kind of, in a dark room, have the scope on, and kind of have your cryoprobe go back too far. Okay? And also, the shaft of the cryoprobe, if you’re pressing hard, can look like it’s the tip of the cryoprobe. So it’s good to look around the eye and make sure you see about 8 millimeters back where the ora should be, and then cryo. Okay? So you don’t want to have shaft depression or improperly placed cryoprobe, due to parallax. Parallax can happen when we’re indenting the sclera in a bullous retinal detachment. And usually if we see a very bullous retinal detachment, when the retina reattaches, the break is often more anteriorly placed than you’d think it would be. Sometimes my fellows say: The retina is really bullous detached. And I can’t get the uptake from the cryoprobe. This is why examination is so important beforehand. I tell them to look at the eye and see what clock hour the break is in. So if it’s 1:00 in the right eye, to have a good exam beforehand. Then when they do the cryo, just try to look around the eye. Make sure they get approximately that position. Often when you’re doing the cryo, the retina will flatten a little bit, because you push fluid out of the break. And they’ll cryo where they think it is. It will make the choroid and the RPE sticky, and then when the retina attaches, it will stick together. Okay. So… Some people think that cryotherapy can induce epiretinal membrane. However, PVD itself can lead to epiretinal membrane, and lots of people get an epiretinal membrane just from having a PVD. That’s why I put up this patient. This is a patient of mine who had PVD in both eyes, and had a pneumatic retinopexy in one eye, and not in the other eye. So it’s actually the left eye, which is on your right — that eye has a small epiretinal membrane, and that eye had pneumatic retinopexy. But the left eye, the eye that’s on your left — his right eye, sorry — that eye has a more significant epiretinal membrane, and that eye just had PVD. No pneumatic retinopexy. So I think it’s a little bit hard to parse out. A lot of people get an epiretinal membrane anyways, when they have a PVD. But overall, I think cryotherapy is easier to do in detached retina. So are there any questions before I go on to the third part here? I’m just gonna take a look and see if there’s any questions. I don’t see any. Because the third part here that I’m going on to now is really one of the most important pieces of doing a successful pneumatic retinopexy. And once I understood this piece of pneumatic retinopexy, my success rate for this procedure went up high. And this is the third piece. This is: How do we support the retinal breaks? You know? When we do a scleral buckle, we support the breaks with the silicone band. When we do a vitrectomy, we support the breaks while the laser’s working with an almost 100% gas bubble. So in pneumatic retinopexy, we support the breaks while the adhesion forms with a smaller gas bubble. About 25%. So the key is to get a single gas bubble. And it’s important to be aware of: How do I do this in the clinic? And inject gas to get a single gas bubble in the vitreous? And that’s because a single bubble, rather than having little tiny bubbles, which we call fish eggs — a single bubble has much more expansile force and works better than injecting the gas and getting a bunch of little tiny bubbles. Okay? These patients have a limited amount of gas in the vitreous cavity for a short duration. Typically I use anywhere from 0.35 to 0.45 of 100% SF6. I personally don’t use C3F8. I think it lasts even too long. And if the procedure doesn’t work for me with SF6, it probably will not work, and they need to go on to have surgery. And we really want to reduce fish eggs, or the little tiny bubbles. That’s what they’re called. Fish eggs. Because they’re not effective, and there can be complicated related to them. And you can see in the slide on the bottom left the schematic of a big gas bubble pushing. It has a better expansile force, and on the right is a picture of a retinal detachment. So in order to inject and get a single gas bubble, it’s really important to position the head correctly of the patient when you inject the gas. And what you want to do is you want to inject the gas in the most superior quadrant of the eye. And I’m gonna show you this. So when I do this procedure, I usually have the patient lie on their back for the entire procedure. So I position their head, I think about where I want to inject the gas. At 12:00, 1:00. You know, I almost always inject at 6:00, and I’m gonna show you why. And I position their head so their chin is up. So 6:00 is the highest quadrant of the eye. And by injecting into the highest quadrant of the eye, you can inject into your gas bubble to get one big bubble. Okay? So I tell patients — if they’re lying on their back, I tell them to position with their chin up. I have them look up. So 6:00 is the highest quadrant. And I do it after the cryotherapy. By doing this, you can inject into your gas bubble. So my technique is: I will have the patient lie on their back, with their chin up. I will inject at 6:00. And I will have my 0.3 CCs of 100% SF6. And I will go in about halfway with the needle. I use a 30-CC gauge 5/8 needle. I’ll go in, a third to halfway. I’ll inject 0.1 CCs of gas. I’ll pull my needle externally, a tiny bit. Just 1 millimeter. And I will slowly inject the rest of the gas. And by doing that, I’m positioning — I’m injecting a little bubble, and I pull my needle back, and then I slowly inject and I’m injecting into my bubble, in the eye. And that’s how I get a single gas bubble. Okay? So this is a very good schematic to show. You want to inject into the most superior quadrant of the eye. The uppermost point of the eye. So on the left, the patient’s lying flat on their back, and you’re injecting into the eye, and you’re getting all these little bubbles. But on the right, this is a patient who is lying on their back with their eye pointing up. So they’re injecting at 6:00. The needle goes in, injects a little bit of gas, then you pull your needle back just a tiny little bit, like a millimeter, and you inject into your gas bubble. Okay? So here’s another schematic showing it. On the left, that’s using a model eye, showing how I position the eye. And on the bottom right is my fellow, demonstrating how we position patients if we inject gas at the 6:00 position. Which is what I always do. I think I have a video here, kind of demonstrating this. Because it’s so important. This of course is not the size needle or syringe, but… Let me see. Let me see if it works. Unfortunately it’s not working on this showing. But the needle goes into the eye. At 6:00. 4 millimeters behind, at the pars plana. Inject a little bubble. Pull the needle externally a bit, and then inject into my bubble. Okay. So when people inject gas for this procedure, either you have them lie on their back or some people inject gas at the slit lamp. Personally, I don’t like to inject gas at the slit lamp, and this picture on the left shows someone injecting gas into the quadrant where the retinal detachment is. These patients often have very bullous detachments, and the detachments are almost always superior retinal detachments. So for that reason, I do not like to inject gas into a quadrant where there’s a bullous retinal detachment. Because you could hit the retina. You could also inject gas and it could go into the break. So if you look at the picture on your right, you’ll see that this patient has a retinal detachment superotemporally, and I would not want to inject gas in that patient at the slit lamp, superotemporally. I would like to inject gas inferior, at 6:00, with the patient lying on their back, and their head positioned so they’re looking up with their chin up. Okay? This is showing someone who is injecting gas inferiorly at the slit lamp. And this is what would happen. The gas would come out of your needle like little bubbles. They’re not injecting into the gas bubble. So that is why you want to have them lying on their back and inject at 6:00. Okay. So what happens if you do have this scenario? You inject gas, and you get these multiple little bubbles, which some people call fish eggs? What do you do? Well, the first way to resolve it is: Don’t inject gas the way that you did! There must have been some reason why you got multiple fish eggs. So inject correctly, thinking about the positioning. The other thing you can do is: If you inject and you get multiple little gas bubbles, you can have the patient positioned with their nose to the floor, looking down like this. Often the little bubbles will coalesce into one big bubble. It can take about 3 to 4 hours, up to 12 hours, and then you can have them move their head to position, to close the breaks. Now, some people do this thing where they flick the eye to try to get the bubbles to come together. I don’t recommend it ever. It’s painful. And it does not really work to get the bubbles together. The concern about getting multiple little bubbles is: It will markedly reduce the success of your procedure, and also sometimes a bubble can get into the break, like in this horseshoe tear, and it can keep the break open. So if one bubble does get into the break, let’s say you have one big bubble and a couple little fish eggs, which — that sometimes happens. If a bubble gets into the break, you continue to position the patient, so the break will float up and get the… Sorry, the bubble will float up and get the break. And usually the little bubble will work its way out in one to two days. So this is my overall pneumatic retinopexy procedure. And I’ve been doing this for over two decades. And this is how I teach our fellows at Tufts. And I find we always do the same thing, and it is very successful on the patients that we do it on. So first, I do a very careful dilated retinal examination, and I get consent from the patient, and they are aware that it’s an office-based procedure. I can do it right when I see the patient. There and then, they don’t have to be NPO. There’s sometimes less insurance issues in the US when we do pneumatic retinopexy. I consent them that if it doesn’t work, then we will be doing another procedure. I take them to a procedure room that we have. I use subconjunctival 2% lidocaine with no epinephrine, and I give a little bit to the site where I’m gonna do the cryotherapy, and a little bit at 6:00, where I’m going to inject the gas. Then I put the lid speculum in, and always put a lid speculum in to do cryotherapy, okay? Because it can be very easy to mistakenly do cryotherapy on the eyelid. So I put the lid speculum in, and I do cryotherapy, wearing my indirect ophthalmoscope, and I treat the tear in the retina. Then I take the speculum out. I draw up my 100% SF6 gas, in a 1-CC syringe with a 30-gauge needle on it. Okay? Then I explain to the patient the head positioning for injecting gas in. And I have them lying flat. I say: This is position one. And then I have them lying with their chin up, and I tell them: That’s position two. And I move them between these two positions. And I put the lid speculum in. I put some Betadine on the eye. With their head flat, I do a small paracentesis, and I remove about 0.1, maybe a little bit more. Especially more if they’re pseudophakic. I remove 0.1 CCs of anterior chamber fluid. Okay? Then I have the patient positioned with their chin up, and look up superiorly. So 6:00 is the highest position of the eye, and I inject the gas the way that I told you. I go in, I inject a tiny bit, I pull back, and then I inject the rest slowly, to get one single bubble. Then I put them back in position one, and if their pressure is high, I do another small paracentesis and put another drop of Betadine. Then I wash the Betadine off the eye. Then I slowly have the patient roll on their side, sit up, check their pressure, put some ointment in their eye, patch, and actually I explain positioning to them, because you want them to position so the break is the highest point of the eye, so the bubble will come up and close the break. I often tell patients — I say, you know, you can’t watch television if it’s up on your wall, because you’re not gonna be positioned properly if your head is up. They have to keep their head looking down or to the side, so the break will be pressed on by the gas bubble. Then I send them home. We see them a day after, and then we see them a few days after that. So… Do I have any questions about the procedure? I have one question. Which gas is ideal for pneumatic retinopexy? Is there any specific indications? Okay. So I’m gonna answer this question live. So people… For this procedure… Like, for example, in retinal surgery, when we use gas in the eye, we don’t typically use — like, for vitrectomy, we don’t use 100% gas. I typically use 20% SF6 or 15% C3F8. That’s what I have access to. But for pneumatic retinopexy, we usually use 100% gas, but of a much smaller volume. 0.3, 0.35, maybe 0.4 if someone has a big eye, or if they have low pressure. In my hands, the SF6 lasts 7 to 10 days. And it really expands the most for the most 3 or 4 days. That’s what I like to use. It doesn’t last as long as C3F8. And to tell you the truth, if it doesn’t work after 3 or 4 days, it’s unlikely for the procedure to work. Other people do use C3F8. I am personally not as much of a fan of that. But I think 100% SF6 is ideal. I have another question. Do I perform drainage of subretinal fluid in the office for this procedure? Never. Never. Never. I only basically — cryotherapy, paracentesis, inject the gas, sometimes another paracentesis, and strict positioning. I think that if you’re gonna drain subretinal fluid on the outside of the eye, you have to really have an infusion in the eye, because you don’t know how much you’re gonna get out, and the ideal thing in that case would be to have a vitrectomy in the operating room. Any other questions, before we go on to complications and some of the pearls from this procedure I’ve learned over the years? I have one question. Can you inject at 4:00 or 8:00, instead of 6:00? So you could. As long as you make… You can, as long as you make 4:00 the highest point of the eye. So I’m gonna try and show you. So if you’re lying on your back, and your head is up, 6:00 is the highest point of the eye. If you wanted to inject inferotemporally, you’d have to make inferotemporal the highest point of the eye, and have the patient look the other way. So in the old days, which unfortunately I remember, we used to do things like air-fluid exchanges in the office. Not uncommonly, we’d lie on the floor and inject air and pull back gas. And you had to do it at 6:00, lying on the floor underneath the patient. And this is kind of like that. You could technically inject in any quadrant, as long as you make that quadrant the highest point of the eye. So I have a friend who likes to go temporally. So he has to make that the highest point. But for me, 6:00 always works. No matter what the configuration of the retinal detachment is, they’re almost never bullous at 6:00, these patients. They could be bullous nasal or temporal. So I think if I make it easy for myself, then I have a higher chance of success. I have another question. Any severe complications? I’m gonna go through some of the complications in the next part of this talk. And how to avoid them. Do I reposition the head in a rapid movement or a slow movement? I do not reposition them rapidly. So I think I do everything kind of in a slow, controlled fashion. When I have them go from position one to two, it’s all slow. No need to be rapid. In fact, it could even break up the bubbles. Someone asked: How much time do you wait to laser? So some people prefer to do this procedure, and instead of doing cryotherapy, they inject the gas bubble in the office, and they bring the patient back for laser. And ideally, you should do the laser when the retina is attached. Because the laser only works if your retina is completely attached. You can’t laser through detached retina. Ideally that would be 24 hours after injecting the gas. But patients are usually really uncomfortable, 24 hours later. That’s why I prefer to do cryotherapy rather than laser. But I think if you’re gonna do laser, if that’s what you have available to you, you should try to do it one to two days after injecting the gas. And the reason you want to see the patient the day after injecting the gas is to check the pressure and make sure they don’t have an infection. So if I don’t have cryo, what’s the best time to laser? Ideally one day. You might even be able to do it up to three days, as long as the retina is attached where the break is. Can air be used instead? You can use air, but I think — I’ve personally never used air. I think that it might be less successful with air, because air doesn’t have that expansile quality that gas does, and that’s really important to having this close the breaks. How hard is it to do laser the next day with the bubble in? It can be challenging. A lot depends on the patient. So it’s a little hard. If you don’t have indirect laser, it can be pretty hard to do laser, for example, if the break’s at 12:00 in a patient, and their head is at a slit lamp, and you’re trying to get laser at 12:00, and the bubble is in your way. If you have indirect laser, you can kind of lie them on their back and work around the bubble, but it can be challenging. If the pressure is raised, which medicine is preferred? So if the pressure is up, and this is what I also teach my fellows, even after vitrectomy, I say: Why is the pressure up? Is it up because you have too much gas in the eye? There’s a gas overfill? Or too much in the vitreous cavity? If that is the case, usually the angle will look narrow. Or is the pressure up because of inflammation in the eye? Because then the angle is open and you treat that with steroids. Typically if someone’s pressure is a little high after this, I use brimonidine. Someone else asks: How to extract subretinal fluid? Basically by closing the break, the subretinal fluid will go away. That is one of the principles of retinal detachment surgery. If we treat the break, we seal the break, and we support the break, the subretinal fluid should be pumped out by the RPE and go away on its own. How much gas is injected? Depends a little bit on what the pressure is on the eye before you start the procedure. So these patients usually have lower pressure. So if that’s the case, you can inject a little bit more gas. But I usually inject about 0.35 CCs of 100% SF6. Okay. I have another question. And sorry I’m not saying everyone’s name with the question. I’m just reading out the questions. But… Can it cause pupil block glaucoma? It shouldn’t cause pupil block glaucoma, typically. I mean, I like to do a paracentesis, then I inject the gas, and then when I’ve done that, if the pressure is still high after — if the pressure is high after, I’ll do another paracentesis. So I’ll usually do paracentesis, gas, and then paracentesis. And when patients are finished with the procedure, their pressure is 12. And I’m injecting 0.35 CCs of SF6. They don’t usually come in with high pressure the day after. This is a good question. Is there any contraindication in young patients with attached vitreous? So studies have looked at whether patients have a PVD or not. The thinking is that if a patient has attached vitreous, could injection of a gas bubble lead to more pulling of the vitreous and more breaks? You know, studies haven’t really shown that. I think that young patients with attached vitreous might get more breaks anyway. Sometimes they develop another break. So there doesn’t seem to be a contraindication in young patients with attached vitreous. But if there are a lot of peripheral retinal abnormalities, like a lot of lattice and stuff, this might not be the best procedure, if there’s extensive peripheral changes. Do I give mannitol pre-op? Nope. Is the volume of gas injected dependent on the axial length? That is a good question. You can probably inject more gas into a myopic eye. But I don’t typically inject more gas. As I said, about 0.35 CCs of SF6. If the pressure is low or the patient has a big eye, I might inject 0.4 CCs of 100% SF6. Have I had any IOL opacification after pneumatic retinopexy? I have not. I have not. That is an interesting question. Certainly there have been cases of IOL opacification with the Akreos intraocular lens, related to gas. Here, most people don’t use the Akreos lens primarily. They use it for cases of sutured IOL, and those cases might not be ideal for pneumatic retinopexy. But I have not had one where I’ve had opacification. What is the preferred location for the cryoprobe from the limbus? So the ora serrata is about 6 to 8 millimeters behind the limbus. So that’s usually where the cryoprobe falls to get the breaks. Do I use it in pseudophakic patients only? Or only phakic? I will use it in both pseudophakic and phakic patients. With a superior detachment, where I have a good idea where the break is, preferably I see the break, or a very small superior detachment. But the phakic status for me doesn’t affect whether I would do pneumatic or not, unless I saw too many breaks to catch with a gas bubble. We never, ever inject subretinal fluid prebullous detachment, and I’m gonna take this as the last question, because I want to go into the complications for you. How much fluid is removed in the paracentesis? I remove about 0.1 CCs of fluid. If they have a very large anterior chamber, you can sometimes remove a little more. So I remove 0.1 CCs in the paracentesis. Then I inject 0.3, 0.35, and then typically I do another paracentesis after, and remove a little bit more. Often people’s pressure is lower from doing the cryotherapy, or from having a retinal detachment. Last question. If the first time the retina does not attach, can a repeat be done? Occasionally yes. You know, it depends on the cause. If the retina doesn’t reattach, and I always say to my fellows: Why didn’t it reattach? Is it the same break? Did they not position? Was it an issue with the gas? Do they have a new superior break? You know, I want to know why it didn’t work. If I think the procedure didn’t work because the gas didn’t last long enough, or the patient didn’t position, and they really wanted to repeat it again, I might repeat it again. But if it didn’t work because there’s a new break, you know, inferiorly, then I wouldn’t repeat it again. So it depends on the reason. Can you do it in incomplete PVD? Yes, we really don’t look at the PVD status so much. It would be better if people had a PVD, but we do it on patients with and without PVD, and have had similar success rates. Okay. Those were all great questions. I’m gonna go back. I saw someone else just put a question in. But I’ll get to it at the next step. Because I want to see… Some of these might be answered when I talk about the complications. Okay. So I just wanted to show you… This is an extreme case of pneumatic retinopexy that I did. This is a patient who came in, and he has this superotemporal mac-off detachment. But if you look inferotemporal, you can see there’s some pigmentation there. This patient had a history of trauma in his eye, some sports-related trauma. And superotemporally, actually, this is a retinoschisis-related retinal detachment, and the patient had about 12 small holes in the retina. You can see a bunch of them that are around that blood vessel. Okay? So I did a pneumatic retinopexy in this case, and this would be an extreme pneumatic retinopexy. Not your straightforward retinal detachment case. Had about 11 or 12 holes. They were a little more posterior. There was retinoschisis. And this patient did very well. Came back to 20/20. So once you’re more familiar with this experience, and have repeated it a few times, then often we will do cases that might not be the classic pneumatic retinopexy candidate. Okay? With more holes, or holes that aren’t breaks — that aren’t within one clock hour. But in the beginning, if you’re new to this procedure, I would recommend starting with the classic candidates first. Okay. So complications of pneumatic retinopexy. So the majority of complications are avoidable with two things: Proper technique, and the second is patient cooperation and of course picking the right patient. So it’s important to get experience choosing the correct patients, experience with the procedure. There is a learning curve. And it is important to practice this procedure. So let’s talk about failure of the procedure. Why doesn’t it work? There could be persistent vitreous traction on the break, keeping the break that you do open or leading to a new break. And this was shown by Dr. Bowman’s study to be one of the major causes of failure. Patients could have a known vitreous disorder, abnormal-appearing vitreous. If that is the case, if there’s vitreous traction on the break, I would consider an alternative procedure to pneumatic retinopexy. Another reason why the procedure could fail is due to a missed break. So my plan for that is I always consider Lincoffs rules and make sure that where I think the break is is consistent with the shape of the detachment. Okay? So what are some other complications of the procedure, of pneumatic retinopexy? And they’re related to the different steps of the procedure. Cryotherapy, gas, paracentesis, and the intravitreal injection. So I’m gonna go through each separately, and most of these have a plan or a way to avoid the complication. Okay. Complications of the cryotherapy. Sometimes with cryotherapy, if it’s very cold and it’s taken off too quickly, or in someone who is very near sighted or has an unusual eye, you can get subretinal or intraocular hemorrhage. If you take the cryoprobe off too quickly, you can get a crack or a new break in the edge of the cryotherapy. And sometimes if you cryo in the base of the break, you can get pigment dispersion during the cryotherapy, which might be a nidus for PVR. So how do you avoid these? Well, the plan is: Brief until you see the uptake. You do cryotherapy briefly, and when you see the uptake of cryo in the eye, you stop. Don’t move the cryoprobe until it is completely thawed. And I always hold some BSS in my hand to help thaw it. And at the same time, keep the cornea wet. Avoid very heavy cryotherapy or excessive indentation of the eye, especially in myopes, to reduce the chance of hemorrhage. And avoid doing cryotherapy in the bed of the break. So in the base of the horseshoe tear. You don’t want to get right in the middle. You just want to try to get the edges, and then anterior from the back edge to the ora. Okay. Here are some other complications of cryotherapy. Sometimes the cryoprobe can be overly posteriorly placed, missing the break and actually going posterior to it. The way to avoid it is to properly position the probe holding the probe correctly. Most of the probes should be held almost with your thumb on the front, and there’s some striations on the back of the probe, where your index and your middle finger should be holding it. So almost like this. Okay? And avoid shaft depression, from the shaft of the probe, and beware of something called parallax, which is the appearance — you look at the shaft and you’ll think that it’s the end of the probe, and it’s not. You also want to avoid cryoing the lid, which would lead to hypopigmentation. And you can do this by using a lid speculum and being aware of your hand position. I’ll look to see where my hand is placed. I’ll be looking around the eye before I do my cryotherapy. So next, paracentesis. What are some of the complications that can happen with paracentesis? Hemorrhage in the anterior chamber from iris trauma or intraocular pressure fluctuation. So I do this by… During my procedure, I avoid having the pressure be too low or having big pressure fluctuations, by doing two paracenteses. Especially if the patient is phakic. I use a 30-gauge needle for paracentesis. And I keep the bevel up. Okay? If a patient is pseudophakic, I do the paracentesis bevel up, and I put the needle usually over the center of the lens. Okay? To avoid any vitreous incarceration, if they have vitreous in the anterior chamber and their capsule is not intact. And of course, if someone is phakic, you want to do the paracentesis over the iris. You do not want to do it over the lens. Because you can hit the lens. So you want to do it over the iris. Kind of pointing at an angle. And when I do a paracentesis, I use… I’m always bevel up. I use the 1-CC syringe, and I take the plunger out, and I use a Q-Tip, a sterile Q-Tip, in my left hand, to gently press at the limbus, to push fluid into my paracentesis. I find that it’s a little hard to pull out with two hands. I like the control of having each hand doing something different. So… Next, what are the complications of pneumatic related to gas? And these are important, because we’re putting gas in, in the office. There’s a few things. The gas can be in the wrong position. It can go subretinal. It can be positioned abnormally at the pars plana. It can go into the anterior chamber. And it can go under the conjunctiva. So we’ll talk about each of these separately. So subretinal gas. That can happen — when you inject the gas, you can get small bubbles like this, which some people call fish eggs. So how do you avoid that? Proper injection technique will avoid getting fish eggs. Risk factors of getting a subretinal bubble include having a very large break, having traction on the break, or having the incorrect injection procedure. Right? I know we already talked about this. But I just think it’s so important to inject in the highest point of the eye. If you have a cell phone, take a picture of the image on the left. Because I always use this image to show people. You want to inject in the highest point of the eye. And then someone asked a question: Could you inject at 4:00 or 8:00? And you’ll see on the right hand slide they’re showing someone having an injection temporally. And they’re getting injected in the highest point of the eye. So the needle goes in. You just have to think about where you want to inject, and make that the highest point of the eye. Because you put your needle in. You inject a little bubble. And then you pull back. So you’re injecting into your bubble. Okay? And do not inject in the quadrant where the retinal detachment is very bullous. Which in pneumatic candidates is almost always superior. Because you can spear the retina. Much harder to do. Prevention of subretinal gas. I know. It’s repetitive. Inject in the uppermost quadrant. Hold the needle vertical. Go in shallow. I go in between a third to a half of a 5/8 needle. Okay? Do a controlled, slow injection into the bubble. And inject away from the tear and the retina. So in the opposite quadrant. And I know we talked about this. How to resolve multiple gas bubbles or fish eggs. Inject correctly. If you get them, position the patient face to the floor for 4 to 6 hours until the bubbles coalesce, and then you have them move their head to close the break. I do not flick the eye. Okay? What if you do get subretinal gas? Well, you want to diagnose it early. Some people try to use a depressor to push gas bubbles through the break. I usually have the patient position so the break is superior, and usually the bubble gets smaller after two days, and will come through the break. If it’s a very large bubble that gets into the break, sometimes you have to do a vitrectomy. Sometimes the gas bubble can get caught in the anterior hyaloid face, and if you look at the anatomy here, especially this patient on the right, you can see the hyaloid’s attached. And the anterior vitreous face is called the canal of Petit, and when gas gets stuck there, it’s called the bagel sign. And you’ll see there’s a rim of gas that is immobile. So this happens once in a while. Especially with people who are new to the procedure. And it usually happens because the needle doesn’t go through the anterior hyaloid face. The needle was a little bit too shallow. Okay? Didn’t go in enough. And you can see on the upper left the needle was a little shallow, so it didn’t go through the anterior hyaloid face, while on the bottom one the needle was a little bit deeper, and it did go through… So the upper one led to the complication. So if you have this happen, number one, you can prevent it by putting the needle a little bit deeper. If it happens, have the patient look down to the ground for about 6 hours, and usually the gas bubble will break through the anterior hyaloid face, and the procedure will be successful. You have them look down to the ground for about 6 hours, and then position so the break is closed by the bubble. If that doesn’t happen, you could remove the gas by releasing it in the clinic, and then rejecting the gas. Complication. Gas displacing fluid in the macula. You can inject the gas, and it displaces the fluid underneath the macula. What do you do? So what you do is you can do something — you can steamroll the patient. Have the patient again move to look down to the ground. And you know what I often tell people? I never have my patients put their face down into a pillow. I just say: Just get your phone and use your phone. Look down to the ground. Like you’re looking at your phone. Which people do for hours every day. And that will help reattach the retina, and then once that happens — reattach the macula. And once that happens, you can reposition the patient, whether it’s sideways to get a break up here, or to get a break up here, after, to close the break. Complication from paracentesis. Peaked pupil. Prevention: Use a small 30-gauge needle and do a pre- and post-gas paracentesis. What if gas gets in the anterior chamber after paracentesis? Sometimes this happens, if people have an open capsule. Sometimes if you do a pneumatic on someone with an anterior chamber lens, when they’re lying on their back, and you’re injecting the gas, you can prevent that while you’re doing the procedure by having them just tilt their head a little bit when you inject the gas, and it also helps to do the paracentesis before gas injection. Then the pressure is not as high, and it’s less likely to happen. But if gas does get into the anterior chamber, you can see, if you position them with their face down, sometimes it will go back. It might go back by the same way it came forward. And it’s been very rare that I’ve had to remove gas in the anterior chamber. Subconjunctival gas. Sometimes there’s a needle tract or vitreous wick. And some of the gas will leak out under the conj. You can prevent that by running a sterile Q-Tip over the spot, after you inject the gas, and not overfilling the eye with gas. And usually we just leave that alone. Vitreous to the limbus during the paracentesis. Sometimes that can happen if you have an open capsule or if there’s vitreous in the anterior chamber. You can prevent that by having bevel up, not continuing to do paracentesis, if there’s limited fluid in the eye. And if someone has an IOL, to position the paracentesis needle over the IOL. So… Just to summarize, pneumatic retinopexy is an effective, highly successful office-based procedure for retinal detachment repair with the correct candidate. There is really minimal complications. Most are avoidable. And I’m open for questions, if there’s any other questions about this procedure. I had one question before. Can you use this procedure for a mac-off retinal detachment with a superior break? And my answer to that is yes. We do it in patients with mac-on and mac-off detachments. Do it also — we’ve had success in this with chronic detachments, as long as they meet the criteria. Single break. You know. Multiple breaks in the superior quadrant, within one to two clock hours. No PVR. No scar tissue, no traction. Is air embolism a possible complication? I have not heard of that from this procedure. I think if you injected into the vitreous cavity, it would be… Not possible. But I have not heard of that. Someone says: I’ve used air. Have you used air instead of SF6? They asked how much air is injected. I have not used air instead of SF6. I think it would be less successful, because you don’t have any expansile force. That’s the one thing about doing this procedure in the office. We inject 0.35 CCs of SF6, but it’s 100%, and it’s gonna expand more than two times its size, and press on the break. And air doesn’t have expansile forces. So I think it would be harder to get the break closed with an air bubble. Any other questions? If you have any comments about this, I know I kind of went through a lot of material quickly. I really think that this is a great procedure for the office. And if you have any other questions, I’m happy if you email me. Because I think this is a great way to kind of repair a retinal detachment quickly, but it does take practice. And I hope the air bubble, sorry, the gas bubble technique is helpful for when you do this procedure. Thank you!

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September 6, 2019

Last Updated: October 31, 2022

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