Today, the CAP technique for flat and fibrotic regions encountered during EMR on the ASGE SUTAB tip of the week. To begin this discussion of management of residual polyp from EMR's previous attempts at resection as well as just fibrosis in general, there's a very nice ASGE tech assessment published last year that reviews the different options and it discusses ablation with the archon plasma coagulator, but generally that's now out among EMR experts. We don't like that because uncontrolled studies have shown that it's associated with an increased risk of recurrence. If you actually burn up visible polyp, that's not as good as resecting it, as removing it. Evulsion is critical in this, can be done either hot or cold. We're going to come back to that in future video tips. They discuss in the paper the grasp and snare technique with a two-channel scope. Endorotor is a through-the-scope device, a special device with an opening on one side near the tip and a rotating blade that can be used to pare down fibrotic areas. Then finally, the endoscopic full-thickness resection device, and we'll come back to that in a later tip. So I'm going to focus here on my own approach to flat and fibrotic disease, and I include both flat because sometimes these techniques are necessary in just very flat areas of polyp that are hard to get a hold of with a snare. Some areas are going to be both flat and fibrotic. So one of these is the CAP technique, and I'm going to spend most of this tip talking about that, and then later we'll come back to evulsion. I have highlighted hot evulsion because that's the way I like to do it, but we also want to learn about cold evulsion followed by snare tip soft coagulation, the so-called CAS technique because there are very prominent experts who are fans of that approach as opposed to hot evulsion. There's never been a comparison of hot to cold evulsion to say which of those is the better technique. So how would you choose or how would I choose between these two techniques for dealing with flat or fibrotic tissue? On the one hand, the CAP technique, on the other hand, evulsion. The CAP technique, I think, is the go-to when the surface area that is resisting standard snaring is larger because if you had to evulse it, pick at it with the forceps, it would take you a significant amount of time. You can remove a bigger piece in one application with a CAP technique than you can with the use of evulsion forceps. In general, I will say that there's a small percentage of lesions that are refractory to the CAP technique, but almost nothing is going to be refractory to evulsion. So in a broader surface area where I would choose CAP first, occasionally you will find just resistance to the CAP technique to any kind of snaring and you have to resort to evulsion. So to summarize in the last couple of bullets, if the surface area is substantial, I usually try the CAP technique first. If it's very tiny, I would go straight to evulsion and I would only use evulsion for a large surface area if it has first resisted snaring with the CAP technique. So turning our attention then to the CAP technique or CAP snaring, what do we need to do this technique? So what tools do we need to perform the CAP technique? Well first of all, it goes better with an adult colonoscope than a pediatric colonoscope. The surface area of the CAP on the end of the pediatric scope is reduced enough that it's actually considerably more difficult to draw tissue up into it. And this is basically a CAP resection technique. We are going to lay the snare on the tissue, suck the tissue up through that snare into a CAP, and it just goes better with an adult colonoscope. You want a CAP of the right size. For the Olympus scopes, it could be something different for other manufacturers, but for the 190 series, you want the 15.0 millimeter, for the 180 series, the 15.7 millimeter. Remember that the CAP is invisible when you're underwater. If you like to go in under insertion, that thing is sticking out three to four millimeters. If you're going around a very, very sharp turn, you could potentially catch that turn with that CAP and cause some damage. So don't forget that. These CAPs are made by both Olympus and US Endoscopy. Now for the snares, we want small snares. This is a blind technique. Once that tissue is up in the CAP, you can't see anymore, and so you want to have a relatively small snare so that you're not grabbing a bunch of tissue, potentially normal tissue that's out beyond where you can see. For technicians early in their experience, I think it helps to use a flexible snare. This is the only time in EMR that I use a flexible snare, and the Boston 11 millimeter CAPTIFLEX is the one that I like for this. If the tech is very skilled, they're very good at feeling that tissue blindly. When they've got the snare on the tissue, then you can use a stiffer snare like the 10 to 15 millimeter Boston CAPTIVATOR. The flat adenoma about 15 millimeters in size that resisted snaring, it's a good candidate for the CAP technique. So before we demonstrate the resection of this lesion using the CAP technique, let's load the CAP onto the scope and demonstrate on the benchtop how the technique works. This is the Olympus distal attachment. This is a transparent, soft, flexible CAP that is put on the end of the colonoscope. There is a small hole in the side of it. That hole is placed next to the lens on the scope tip. The device is usually placed to stick a few millimeters out from the tip of the scope, and there it can be used to stabilize tissue for imaging. That's its really dedicated use. However, it's been used in a number of studies to improve detection. You can flex against households, flatten them out to see behind them. This is one of the devices that can be used for this purpose. We're going to discuss its use for the resection of flat and fibrotic regions during EMR. So to put this on, we're going to have the hole side further away from the tip of the scope and the hole side next to the lens, and then we're going to push it on until the device is sticking out about three to four millimeters from the end of the scope. That small amount there is going to be the working area that we'll use to pull tissue up into that space and then close the snare on it. To perform the cap technique, we want to use a small snare. This is a 10 millimeter snare. It's the Boston Captivator 2. This is a blind technique where the technician will close on the tissue without being able to see it. And in general, we said that for EMR, we want to use stiff snares because they grab tissue better. The disadvantage or the difficulty in using a stiff snare to perform the cap technique is that the device is a little bit more difficult to open and not quite as smooth as a flexible snare. So while the more experienced technicians can learn to close blindly and feel tissue as they're closing with a stiff snare, early on in the experience, it can be helpful to use a flexible snare. So I recommend when you're first starting the cap technique, first learning it or working with a new technician who hasn't done it previously, that you use a flexible snare. This is the Boston CaptiFlex 11 millimeter. So it's almost the same size as the 10 millimeter Captivator 2. But because of its flexibility, it has a smoother throw on it. That is, when we open and close it, it feels very smooth. And for the technician who is closing blindly on tissue and relying totally on feel and not vision for closure, and when they're starting to grab a hold of tissue, this can be a real advantage. So let's go through how the cap technique works. The first step is we are going to place the snare over the tissue, the target tissue, the flat or fibrotic tissue, which is represented here by the tip of my finger. Obviously, it's not really flat or fibrotic. So we have to imagine that it is. So first, we're going to place the snare. The second one is we have to approach very closely with the colonoscope. And the reason for that is that we're going to apply suction to the tissue. If we're back two or three centimeters and we apply suction, tissue is going to come in from the sidewalls of the colon and fill up the cap. And we want to make sure that it's our target tissue that fills up the cap. Step one, snare over the tissue. Step two, approach the tissue closely. Step three, apply suction. At that point, once we apply suction, the tissue is going to come up and fill the cap. And at that point, we're blind. We can't see. So when we're comfortable that we've got good suction, then we're going to say to the technician, okay, close the snare. And now they are blindly closing. This is why it requires some skill on the part of the technician, because they have to go by feel. When they feel that they've got it, then they're going to say, I've got it. And at that point, we're going to release the suction so we can take a look at it. Now we've got the snare closed down on the target tissue and we can transect. Now I prefer to release the tissue if I'm performing hot snaring so that I can get a look at it. But actually during cold snaring, you can actually, if you're in a flat EMR, actually transect with the tissue still up in the cap. The safety is provided by the very shallow cap, which means that we can't pull too much up into the tissue. It's very, very rare performing this technique to get injury to the muscle, but it's an excellent way to get a hold of flat or fibrotic tissue. So we're going back now to this lesion that we saw earlier. This is a very flat adenoma. I would say this is Paris 2B. And after injection, it gets even flatter. It's one of the disadvantages of traditional inject and resect EMR compared to underwater EMR is that lesions tend to get bigger and flatter when they are injected. And so this resisted standard snaring, and because of the surface area there, it would be very inefficient to try to take it out by avulsion. We'd be picking at it for some time. So we're going to use the cap technique. So we're taking off the first piece, which doesn't look very big, but we actually going to remove this in three pieces, which is a lot fewer than we would be able to remove it using avulsions. We've taken the first piece off. You can see we're resected in the right plane. Now, step one, place the snare. Step two, approach very closely. You can see we're inching up on the lesion. Step three, we're going to apply the suction to bring the tissue up through the snare into the cap. And step four, the tech closes on the tissue. And this is where that skill level comes in to feel the tissue. And we are using an 11 millimeter flexible snare, which makes that job easier. Step five, we release the suction, take a look at the tissue, and then transect. As I said, if we're doing this cold, we actually can transect with the tissue right up in. There we did a little bit faster. Place the snare, got up close, sucked right through, release the suction, and then do the transection. So very flat lesion removed using the cap technique in three pieces. We're going to demonstrate this more in future tips, various combinations of situations where it can be useful. Now, there's a tiny little piece of tissue there, which I think is too small for the cap technique. You'll recall that for very small pieces of tissue, avulsion is usually preferred. So we're doing hot avulsion there to finish things off. But again, it would have been very inefficient to try to remove the entire thing using avulsion. There's a nice resection, the lesion completely removed. Then we touch up by snare tip soft coag at the margin, and we're finished. Next week, more in the cap technique for resection of fibrotic disease on the ASGE suit tab, tip of the week.

management of residual polyps

fibrosis

CAP technique

evulsion

specific snares