In this lecture, Dr. Pineda talks about cortex removal using irrigation & aspiration.
Lecture Location: on-board the Orbis Flying Eye Hospital, Accra, Ghana
Lecturer: Dr. Roberto Pineda, Harvard Medical School, Boston, USA
DR PINEDA: I/A is actually — people kind of let their guard down when they do I/A, because they’ve done the capsulorrhexis, they’ve gotten the nucleus out, and they’re thinking about the next case. They’re thinking about lunch. They’re thinking they’re done with the case. And this is actually — there’s a lot of important things to consider when we’re doing I/A in cataract surgery. So again, yeah. Phew, the nucleus is out. But we have to think about — these are my financial disclosures, which aren’t really relevant. So most surgeons when training, as I mentioned before, they stress out about the capsulorrhexis. They stress out about the phacoemulsification. But I/A is actually very vulnerable to posterior capsular rupture. In one study, it showed that 34% of posterior capsular ruptures occurred during the irrigation/aspiration phase, or when they were polishing the capsule. Remember, the posterior capsule is a lot, a lot thinner than the anterior capsule. How thin is the posterior capsule? Very, very thin. We’ll go over that. So we’re just gonna talk about a few things, about breaking the capsule. As we like to say in the US, it’s like skating on thin ice or glass. So here we go. So anyway, the posterior capsule is only 4 microns thick. Anterior capsule is 14 microns. And then the rest of the capsule is much thicker. Remember, this is very, very thin. And we have a very famous baseball player in the United States. His name is Yogi Berra. Very famous New York Yankees baseball player, and he said: It ain’t over ’til it’s over. And I agree with that. Your cataract surgery is not over until you actually see that patient the next day, and know they’re doing okay. So let’s talk a little bit about lens cortex anatomy. So really we have a nucleus, but then we have the epinucleus or supranuclear cortex. This is softer. But it’s a continuous cortex around the nucleus. And then we actually have the peripheral cortex. That’s the stuff we’re trying to remove after we’ve taken out the nucleus. And it has actually a fibrous texture, beneath the anterior capsule, and at the equator. And also, on the posterior capsule. And there’s actually cells underneath the anterior capsule and in the equator that actually retain this kind of pseudofibrous metaplastic activity, which actually leads them to have very, very firm attachments to the cortex. That’s always why, when we’re stripping — and again, I want you to focus on the equator. The equator is not usually where we’re removing cortex. We tend to remove it subcapsular. In training. We don’t want to be there. We want to be at the equator. But it’s actually — there are different anatomic — there are anatomic differences in the cortex, at the equator, versus under the capsule and at the posterior capsule. And the analogy we like to describe — many of us use for cataract surgery — is talking about a peanut M and M. Peanut M and M is a great analogy, at least in the US, because everybody knows what it is. And we can say: We open the shell, and we remove the little nut, and all the little material around it. And put in a new nut, essentially. So as I mentioned before, about so many things in phacoemulsification, each step depends on the prior step. So we have to take special care doing irrigation and aspiration when we have a small capsulorrhexis. When we have a torn capsulorrhexis. And when we have weak zonules, which we saw earlier in one of my videos. And even when we do femtosecond laser assisted cataract surgery. We have to take those into consideration. So how do we go about removing our cortex? Well, there’s mechanized methods and manual methods. The most common we typically see is coaxial. What does that mean? That means one piece, one handpiece, where the irrigation and the aspiration are good. In order to make that work, we need a good seal. And that seal is important. So the incision size is important. If you have a large incision, and you don’t have a good seal around that incision, you’re gonna have a harder time removing the cortex. We also mentioned already — so there’s many different types of tips that you can have on your coaxial. Of I/A. Some are for removing subincisional cortex. We have 45-degree, 90-degree, U-shaped, and the disadvantage, as we all know — it’s very hard to get that subincisional cortex. And that’s why we have some of these 90 and U-shaped cannulas. But they often get clogged. So they don’t work so well. Bimanual I/A — I initially, when I learned phacoemulsification, I didn’t really use bimanual very much. But as I get more and more experience, I actually like it more and more, because I can do a lot of gentle I/A, which is hard to do sometimes with a coaxial piece. We need either two paracenteses or at least one paracentesis, and then use your irrigation, still, handpiece, to remove the cortex. And basically — obviously much easier to get subincisional cortex, where you can reach under. And it’s preferable, when you have a compromised zonule or capsule. They come in metal or silicone tips as well. This is actually kind of important. Your port size. So the standard port size is usually about 0.3. Some of the 90-degree tips have a smaller port size, like 0.2, so it’s like 50% smaller. So it’s much harder to remove the cortex. The sleeves, again, can be either metal or silicone. Obviously you want reusable material here. And then, of course, most of you have experience with the Simcoe. If you’re doing SICS surgery, you’re gonna use the Simcoe or some manual device. I love the Simcoe. In our country, we don’t get that much experience with the Simcoe, but it’s very gentle. Very effective. And it’s definitely something — if you’re doing SICS, you’re probably already familiar with this — and you can easily use this in phaco, in the beginning. So yeah, this is just bimanual here. And the other little different tips you can have for your case. And this is a Simcoe cannula, for those of you who are not familiar with it. So again, all of these techniques work very well. It depends on your setting. So one is not better than the other. They’re just different. You use them in different situations. So we don’t want to single out a particular type of technique, because they’re all very, very useful. So basically with I/A, you want to engage the cortex first in the fornix. And you want to do this with the tip, and you want to be — so this is what I was talking about before. Imagine that backwards C. You want to be in the middle of the C, or the lower half of the C, when you go in to grab the cortex. You don’t want to be at the top part of the sub — just below the inside of the C. You’ll just be grabbing the anterior capsule and not grabbing the cortex. So you need to learn to live a little further down, deeper. I like tangential removal of cortex. That’s a sweeping back and forth, staying just under the capsule. It puts less stress on the zonules. And it’s also extremely efficient. We can watch a few videos here. And you can see that the tangential stripping is much faster. So I operate, when I operate with a lot of residents and fellows, I tell them three principles I operate by, when I do phacoemulsification with them. The first one is safety. So whatever you’re doing has to be safe. The second thing is it has to be predictable. So whatever you’re doing should be predictable. And the third one is it should be efficient. So if you can do something that’s efficient as well, you should do it. But it should be in that safety, predictability, efficiency. So tangential is very efficient. So you’re getting a big bang for your buck. So you want to gently pull toward the center, at the end sometimes, and the vacuum settings are also very important here. Usually this is considered a high vacuum procedure, with high flow. And we’ll talk about those concepts later on. Of course, the subincisional cortex can be more difficult, which we talked about. Either using bimanual, or as I mentioned before, if you can’t get the cortex out, put in the lens implant and rotate it. And then try to get the cortex out again. That usually works very well. So here’s just an example. It’s a little out of focus. Of just some radial stripping. Not really doing tangential. Grabbing the tissue and pulling it radially. This is very well — loose cortex, so it comes out very easily. And you know, he’s not really reaching under. You saw when the person grabbed the capsule, you couldn’t even see the edge of the — you couldn’t see the tip. So it’s better in the beginning to keep — if you’re doing coaxial I/A, to keep the tip a little visible. So this was an easy one. Really easy. Looks great, too. Right? So most of us know it’s not that easy. So I’m not sure what’s going on there. But I think they’re trying to get something out. So this is just another case. Trying to strip — they’re doing this radial stripping. And again, you know, you want to be able to visualize your tip. This is a 45-degree angle tip. And again, this is a common tip we use. This is an all-metal tip. Just on a silicone sleeve. We have silicone sleeves. We can be a little more aggressive with them. But again, we can just radially strip the cortex off. And again, it usually works very well. Again, radial is easy for people to understand, but it puts a lot of stress on individual zonules. Here again you can see the person struggling with the subincisional cortex. In this case, we have the small pupil. Red reflex is not as good. Much harder to see. We’re trying to use a second instrument to remove — to visualize the cortex, so we can remove it. This is more an example of tangential stripping. So here we try to keep — this is a silicone tip. You can be a little more aggressive with that. But you can see we’re just staying just under the anterior rhexis. A little deeper. And we sweep right underneath, subincisionally, as well. And you can quickly remove all of the cortex. And again, I like this technique. It works very well for most cases. Sometimes it sticks a little bit. But this can be fairly a blind maneuver, and a lot of people are uncomfortable with that, which is why they like the bimanual technique, because they can see things a little bit better. This is just, again, talking a little bit about the fluidics. So in general, the vacuum is very high. To remove the cortex. And the aspiration rate or flow rate — so aspiration and flow, they mean the same thing. You’ll hear both. Some people talk about flow rate. Some people talk about aspiration. But they’re really the same setting. With the infinity machines, we usually have a bottle height of around 100 centimeters. And sometimes if we’re using the newer Centurion models, you might see numbers like around 60 or 70 millimeters of mercury. But these are all — for the cortex, you’ll notice cortex and viscoelastic are very similar. Numbers are not very different. Obviously, if we’re gonna polish the posterior capsule, which we’ll talk a little bit about more, this is a very low flow, low vacuum setting. We don’t want to be grabbing the capsule aggressively. So this is just a little bit about some stubborn cortex strategies. So, again, bimanual — so the bimanual or to get the subincisional cortex, you can use bimanual, which we talked a little bit about. Or you can use the U-shaped or 90-degree coaxial tip. There’s a J-shaped irrigating cannula that one can use as well. You can also viscodissect. You can use viscoelastic to try to push the cortex out of the equator, to try to make it easier to grab. And then you can use the IOL to essentially rotate and loosen the cortex, and remember, as long as you get most of it out, it’s okay. If you leave a little bit, it’s okay. Remember, the enemy of good is the pursuit of perfection. You know, don’t risk rupturing the capsule for a little bit of cortex. It’s not worth it. And basically, for femto laser-assisted cataract surgery, the cortex is very, very sticky. It’s very hard to remove. So I know at the University of Illinois you guys get some FLACS experience. So it’s a different kind of cortical removal than you would with standard phacoemulsification. And we also have — just so you are aware of this — we have handpieces now that allow us — this is the Intrepid? Is that it? Intrepid? That allows you to actually go from a coaxial to a bimanual. You just pull it apart. It’s a disposable handpiece, made with an Alcon phaco machine. Again, this is a bimanual technique. Here are the irrigation — still on the co-axial, so it’s through the main incision. It’s keeping a tight incision. And then we’re reaching down behind the subincisional area, to remove whatever residual cortex is there. And so a lot of people use that technique. If not, you have to create another paracentesis, as was done here. And here we’re reaching — now we have one for irrigation, one for aspiration. And you can see reaching underneath, they’re pulling out the residual cortex. Again, I like this technique a lot. For those of you who use Simcoe, I like the bimanual almost better than the coaxial. Okay. Capsular polishing. This is a completely optional step in phacoemulsification. We can use viscoelastic sometimes to polish the posterior capsule. It’s very safe and gentle. We can get what’s called a capsule polisher or scratcher. And this can be under irrigation or no irrigation. Sometimes the instrument with the circular pattern, as you see here, or we call it an olive tipped cannula, so it’s like a little olive at the end, that has — usually diamond dusted, and you can polish with that. Most of ours in the US are disposable. But they do make reusable instruments. And they can be useful for getting off those posterior subcapsular cataracts that have a residual plaque or film. Sometimes you have to recognize: Sometimes the posterior subcapsular changes obviously can’t be polished off. But in so many cases, they can be polished. I usually polish patients who are receiving premium lenses as well. And you can also do what’s called an I/A capback, where you actually — this is a setting on the phaco machine that allows you to essentially vacuum off the posterior capsule. It’s safest with the silicone tip. But you could use a metal tip as well. And these are very low vacuum settings, in order to do this. But it’s a good technique to learn. I would say it’s a more advanced technique. But it can be very helpful. This is just one of these — we call Kratz-style polishers. I’m directing one of our residents here, who is polishing the posterior capsule. Usually we make circular — we don’t go longitudinal. We make circular movements with this. This can be hooked up to an irrigating cannula. I usually recommend the cannula not point directly at the endothelial cells. That’s not a good idea. So we turn it on the side. This one doesn’t have any irrigation on it. So that’s why it’s a little — but it’s very helpful. We saw our zonular dialysis already. In one of the earlier videos. And pulling tangentially helps to avoid some of that. You can get the cortex first. If you do develop a dialysis, basically you want to do the rest tangentially. You saw we used a CTR in that video to basically help stabilize that. But you want to try to get as much cortex out, especially in the areas that are not involved in the dialysis, before you put in the CTR. And you can also — if it’s a very teeny dialysis, you can put in a three-piece lens, and orient it so the haptics are in the direction of the dialysis. And then sometimes using manual I/A is also helpful. Again, for small capsulorrhexis, bimanual I/A is much preferable over coaxial I/A. And if you have a torn anterior or posterior capsule, manual technique can be quite helpful. And also just using very, very low vacuum settings. So if you do notice a tear in the posterior capsule, what I want to emphasize here is: You don’t want to pull the instruments out. I think when we see a problem, the natural tendency is to pull out the handpiece. And we want to keep the irrigation going. And what we ideally want, if we have access to it, is to put a dispersive viscoelastic first, to cover up the tear. And then remove the instruments. So this is very hard, because usually we’re removing the one handpiece. Someone’s trying to hand us another handpiece. But as soon as you pull out of the instruments, you create a pressure gradient. So the vitreous is gonna come forward and come directly to the incisions. What happens if there’s vitreous prolapse or a tear and there’s cortical material left. This also can be very challenging. Sometimes you have to — depending on where it occurs, you might be able to remove some of it with a bimanual technique. Other times, you’ll have to use the vitrector to remove the vitreous, and then go ahead and remove the residual cortex. We can also use viscoelastics to push some of this material and block it off, so we can go and remove it. So basically this is a difficult situation, but manual I/A, using a Simcoe or a bimanual technique, is much better than coaxial I/A. So just a few parting thoughts here. Cortical clean-up can be very rewarding, but also potentially dangerous, because there’s a time when the posterior capsule can be torn. We should be familiar with multiple approaches to removing I/A, both coaxial, bimanual, and manual. The best time to learn is obviously now, in your training session, and hopefully we’ll have some experience during the next few days, where you can master this part of phacoemulsification. Thank you very much.
December 4, 2019