Next lecture will be regarding Phaco techniques. We're going to go over both divide and conquer, along with the chopping technique. Chop can be referred in different ways. Some people use the terminology Quick Chop or Stop and Chop. There's also a distinction to be made between horizontal chopping and vertical chopping. We will go over all of these things today. The goals, when you're doing cataract surgery of course, is to remove the nucleus as safely as possible. Once you're sure you can remove it safely, we want to do so with as minimal phaco time and energy as you can, to protect the endothelium and to minimise complications. The most common technique that's used, when you first start doing cataract surgery, is divide and conquer. It's considered the safest form of cataract surgery, but it's also often the slowest. Typically use a higher amount of phaco time and power, because there's more sculpting involved than when you're doing chop technique. When you're in a residency, this is typically how you first start learning phaco, and it's an easy thing to do, when you're first getting inside of the eye. However, many very experienced surgeons are very good at divide and conquer, and can be just as efficient with this technique as others are who chop. There's nothing wrong with doing divide and conquer, and there's nothing wrong with doing chopping, but typically, people do start with divide and conquer. Eventually, they learn chopping also, then, they decide which technique is best for them. Here's one video showing what divide and conquer is like. The main point in divide and conquer, is you're going to create two sculpts, and the two sculpts are in a cross-like fashion. Once you have those two sculpts, you then put your instruments into those trenches and break the nucleus into four different quadrants. That`s the divide portion. Once you're in four quadrants, you then remove one quadrant at a time, which is the conquer portion. Again, here is the video that shows it. >> For divide and conquer, you want to separate the nucleus into four quadrants and remove them one by one. Here, the surgeon is separating the nucleus in half, so he's creating a groove. As he deepens it, the red reflex becomes brighter. He's rotated the nucleus to extend the groove across, to make it easier to divide in half. He's using the dry steel and phaco tip, to separate the nucleus into half. Then, he's using the phaco tip to divide half of the nucleus in half and to create quarters. As you can see, the red reflex is brighter and then he's using the two instruments to divide in half again. And then the last half is grooved and separated. Now he's removing each quadrant, one by one. And he's using the second instrument, the Drysdale, to help feed the nucleus into the phaco tip. And the phaco tip is buried into the nucleus, the vacuum is built, then the piece is pulled towards the center, where emulsification can occur safely, away from the posterior capsule. And this continues on, until the last piece is removed. And the last piece should be removed carefully, since there is nothing between the phaco tip and the posterior capsule. So you can use your Drysdale to protect the phaco tip from capsule. >> Here is the schematics of showing how you do the sculpting. So here, to orient yourself, this is the capsule cataract that's already been performed. This is the phaco end piece that's going through and creating the first sculpt. Once this is completed, you'll then rotate the nucleus, 90 degrees and then create a second scope, until you have a complete cross. Once you have that cross, you use your phaco end piece, along with a second instrument of your choice, to break this nucleus into those four pieces. And then, once those four pieces are isolated, you remove them one by one. When you're doing divide and conquer, along with any chopping techniques, there's typically two steps using the phaco machine. The initial step is sculpting, which is when you're making the initial grooves, as I showed on the previous slide. The second step is emulsifying. Emulsifying is once you have your quadrants, and then try and eat each one of the quadrants separately. This is the settings for the BCS book. This was done prior to the was invented, so this was traditional phaco time. But as you can see, the amount of power is higher when you're emulsifying, as far as the max power is, but the biggest difference is the amount of vacuum. When you're emulsifying and you're removing the quadrants, you want to have a significant amount of vacuum. So when the piece comes towards you, you can hold it while you're eating the entire piece. When you're sculpting, it's the opposite, you don't want to be holding on to the nucleus. You want to be cutting through it and making your grooves, which is why the vacuum is lower for sculpting than for emulsifying. The other main distinction between sculpting versus emulsifying, is when you're sculpting, typically you do not have the entire tip buried in nucleus. You have 50% of the tip that's occluded, and the other 50% is open to just the anterior chamber. When you're emulsifying, you like to have the tip fully occluded. And when you get the tip fully occluded, that's when the vacuum kicks in, which tries to hold the piece onto your tip, while your phaco is eating it. Continuous phaco is typically the mode that's used when you're doing the sculpting. You can use sporadic phaco, or continuous phaco, when you're emulsifying. Again, this is where osol typically kicks in more at this point too. Chopping is similar to divide and conquer, where you still try and divide the pieces into smaller quadrants to remove them, however, you do less sculpting in order to remove them. So less Phaco time and energy is used, because less sculpting is required when you chop. The difference between chopping and divide and conquer is typically the second instrument, which in this case is, of course, a chopper. A chopper tends to be sharper, because that's using that sharp point of that chopper to break the nucleus into multiple pieces. Having the sharper instrument inside the eye, can lead to a higher risk of tear, especially when you're first learning this technique. When chopping initially came out, there were some studies that thought there was less stress on the zonules, when you did chop. There's now been other studies that say that may not necessarily be the case. As far as terminology is concerned, some people use the term quick chop, others use the term stop and chop. What this means, is a quick chop is when you don't do any sculpting at all. Essentially, you take the nucleus and you impale the Phaco handpiece directly into the center of the nucleus. Then, you use your chopper to go next to the nucleus and then spread that chopper and Phaco handpiece apart, and that will split the nucleus in two pieces. And you then keep doing that same technique, until you have small enough pieces to eat all with the Phaco handpiece. Stop and C hop is when you do one sculpt down the middle, and then you break it into two hemispheres, and then you take each hemisphere and chop those instead. So quick chop and stop and chop, are just terminology indicating whether you chop right away, or whether you're doing some sculpting first. As far as which chopping technique you use, there's two most common ones are the horizontal chop and the vertical chop. These techniques are named for which direction you're moving the second instrument. When you're doing chopping, the initial step is to remove the anterior cortex with your phaco hand piece, to then expose the nucleus. You then take your phaco tip and you impale it deep into the nucleus. This is different than when you're sculpting. Again, when you're sculpting, you're just secluding 50% of your phaco tip and just kind of rubbing on top of the nucleus, until you keep grooving each step until you get deeper. In this case, you're not trying to skin off the top, you're trying to go directly to the nucleus. Once you are impaled into the nucleus with your phaco handpiece, you then take your second instrument, the chopper, and you slide it along the endonucleus in a hydrodelineation plane. And you go 180 degrees away from your incision. When you're 180 degrees away from your incision, You then have the chopper grab the nucleus, and pull towards your phaco tip. When that chopper has then cut through the nucleus, and you're close to the phaco tip, you move the chopper and the phaco tip in opposite horizontal directions. And that then splits the nucleus into two pieces. You will see a video of horizontal chopping which will explain it very nicely. The one thing about the horizontal chop is that when the initial secondary instrument goes under the capsule rectis, it's often a blind pass to grab the edge of the nucleus. This can be a bad thing and a good thing. It's bad, because you can't always tell if you're on top or beneath the capsule depending on how small the iris is. In order to ensure you are underneath the capsule, you want to make sure your second instrument is touching the nucleus, is rubbing on the nucleus as you slide that instrument out into the periphery. As long as you do that, you can be sure that you're under the capsule rectis. Certainly it would be a big problem if you were on top of the capsule rectis, and then you start to pull that instrument towards you to try and split the lens. However, the good thing about not being able to see in that areas, when you do get challenging cases that have small pupils, you're very comfortable to working in an area, where you're not seeing as well as you could possibly could be seeing. When you're horizontal chop, there is a higher percentage of getting an anterior capsule tear nasally. This is, again, because you're sliding out your second instrument right in this area. If the head of the tip of the chopper pointed a little bit towards the endothelium, as you're sliding it out, you can nick the capsule, which will then cause anterior capsule tear. A horizontal chop is nice to use for either soft or hard lenses. Next, we'll move on to vertical chop. Vertical chop initially is the same as horizontal chop. Initially, you remove the anterior cortex to expose the nucleus. Again, you take the phaco tip and you do a deep into the nucleus. Just like horizontal chop, you're not doing the sculpting, where you're shaving off the surface of the nucleus, you're actually just going straight to the nucleus initially. This time, instead of taking the chopper and putting it in peripherally, instead, you're going to go directly next to the nucleus, right by where your phaco tip is impaled. You then will take your chopper and push it posteriorly, while you pull your phaco tip anteriorly, this is the vertical motion for the vertical chop. In reality, it's not really a complete anterior and posterior movement, it's more of a diagonal movement, where you're taking your chopper and kind of pushing it down in a away, while you're taking your phaco handpiece and kind of pulling up in the opposite direction. Those two motions should crack the nucleus nicely. Here's a video that illustrates vertical chopping. And you'll see the difference here between vertical and the horizontal chop. >> The anterior cortex has been removed to expose the nucleus. The phaco tip is impaled deep into the nucleus. Then you slide the chopper into the nucleus, under direct visualization, near the phaco tip. Then the chopper is pushed posteriorly, while pulling the phaco tip anteriorly to correct the nucleus. Again, the chopper is down and away and the phaco handpiece is pulling up and in the opposite direction. And this is repeated until the nucleus is cracked into small pieces. And now that the cracking is all done, each piece is removed with the phaco handpiece. And the chopper is being used to continue to break the nucleus down into smaller pieces. Using vertical chop, you can remove a relatively dense lens, as shown here, with a very low phaco time. And once all the pieces are removed, what's remaining is the epinuclear shell. And that shell is a nice protection for the posterior capsule. So here the last piece of nucleus is being removed. >> One advantage of the vertical chop is you can see where the chopper is the entire time. There is no blind pass like there is with the horizontal chopping. This one is better to use for harder nuclei. If you get a patient who has a solid three plus nuclear sclerotic cataract, this will chop very nicely with the vertical chop and it's very easy to use. And will save you significant amounts of phaco time and energy, as opposed to divide and conquer. However, if you get a very soft nucleus, like a primarily a a posterior subcapsular lens, it's very hard to vertical chop those nuclei. In those situations, I either use a horizontal chop or I'll use divide and conquer. Some people get concerned about vertical chopping, because the vertical chopper, in particular, has a sharper tip on the end of it. And since you're moving it posterior while you're trying to break the lens, people get concern that you're moving towards the posterior capsule. While this is true, you are moving in that direction, the depth of the vertical chopper is very shallow in comparison to the depth of the full nucleus. So you shouldn't be pushing hard enough to go all the way to the nucleus with the chopper, and then through the posterior capsule in addition.
