the week. The paradigm of modern colorectal EMR using electrocautery is snaring followed by avulsion if it's needed to complete the resection and then after all the resection has been completed we treat the normal appearing margin where we can't actually see any residual polyp with thermal injury usually using the snare tip on soft coag. We covered that in the very first SUTAB video tip. So now we're returning to this issue of avulsion that is needed in some cases in our experience we use it in about a third of all referred lesions large lesions for colorectal EMR and it can be done either with hot forceps or with cold forceps. Hot forceps, hot avulsion, cold forceps, cold avulsion. Cold avulsion is usually followed by snare tip thermal injury to the avulsed area that's the cast technique. I personally prefer hot avulsion. I think it's cleaner and that's going to be the subject of the next two to three video tips but to go back to the basic principles here we no longer treat any visible residual polyp by ablation. We don't get the argon plasma coagulator out or a laser and actually destroy visible polyp tissue because it's been associated with a higher risk of recurrence. Rather we want to remove it using forceps and that will remove it resect it in the same plane that we were snaring in. So the idea of avulsion is that when we have an island of residual tissue rather than ablate it with APC we're going to pull it off with forceps. We're going to grab hold of it. If we pull it off with cold forceps that's cold avulsion. In this case we're using hot avulsion, hot forceps. Grab the tissue lift it up into the lumen and then we will tap at the final moment when we're happy with the stretching the cutting current and it'll come right off in the same plane that we were snare resecting in. That is hot avulsion. To summarize the uses hot forceps, hot avulsion, their appropriate use currently in colonoscopy is as a salvage method after snare failure during EMR using electrocautery. That's what we're going to be discussing over the next couple of video tips. I think it's also okay to use them to remove very flat recurrent polyp on EMR scars at follow-up and that's the only uses that I put them to during colonoscopy. As a reminder they should not be used to resect diminutive polyps during colonoscopy. They certainly shouldn't be used as a primary tool for resection of larger polyps and they should not be used to biopsy a lesion before referral. That's going to produce semicostal fibrosis that will interfere with subsequent resection. Unfortunately I actually have seen that happen a few times. So why do avulsion hot rather than cold? Critics of hot avulsion are often concerned about the risk of using hot forceps. In my experience it has proven to be extremely safe and it's also very clean. It leaves the field dry in the great majority of instances where it is used. Cold avulsion on the other hand sometimes causes bleeding and is followed by the use of the snare tip and soft coag treatment over the avulsed area. So you're using two tools. I find it to be not as efficient as performing hot avulsion but I would point out that there are no head-to-head comparisons and either is acceptable as a way of removing flat or fibrotic tissue during EMR. So hot avulsion, the first step obviously is hot forceps. This is the only time during colonoscopy that hot forceps are used. They should not be used for the removal of diminutive polyps but they can be used for hot avulsion in the base of an EMR defect or to remove very flat tissue on an EMR scar at follow-up. And this drawing depicts the normal mucosa. The blue is the EMR defect. That's our flat residual tissue. Here's the submucosa extending out past the defect and the muscularis propria. And as we approach the tissue that we want to get a hold of, our goal is going to be for the tips of the forceps to be in the submucosa adjacent to it. In other words, we've got to get enough tissue. We don't just want to grab the top of this. We want to actually get into the submucosa. On the other hand, we don't want to get a huge amount of submucosa because we don't want to risk grabbing a hold of muscularis propria. So typically the tips of the forceps, the arms of the forceps are going to be in the submucosa a millimeter or two to the sides of the target tissue. So step two to emphasize this, the forceps placement. We're shooting for a millimeter or two of submucosa around the target tissue. We don't just want to grasp the top of the target tissue. We've got to really get a hold of that target tissue. But on the other hand, we're trying to avoid going too deep. So the right amount of submucosa on either side of the target tissue is important. So here we show the forceps are now closed. The target tissue is inside the forceps. And a point that's important, especially with fibrotic tissue, is that we need a firm grasp. So we need to close tightly enough that we can really hang on to that tissue when we start to tent it, which is going to be the next step. Step four is to produce some mechanical tenting or pull on the target tissue, either by pulling away or by lifting up the forceps. And the value of this is, first of all, to get further away from the muscular propria. But our goal is to separate this tissue in the same plane that we have been snaring in. So we want to have the tissue tear away in this submucosal plane. And the mechanical tenting helps that tearing occur. The goal when we're done is that the submucosal defect, our EMR defect, looks uniform across. We haven't burned up this tissue. We're not guessing whether or not we have destroyed the tissue. Rather, we have removed it with forceps in exactly the same plane that we were resecting earlier with the snare. And so the areas that have been removed by avulsion and the areas that have been removed by snare look very similar in the EMR defect. A few important points that might seem obvious but should be made. First of all, when we're doing hot avulsion, the forceps don't have to be fully open. In this case, you can see with a fully open forceps and a very small diameter target, we would put several millimeters of submucosa in the forceps, which is more than we really need. So we could partially close the forceps and then push them into the submucosa and just get a millimeter or two, still get the target tissue, and we'll have less risk of getting all the way through the submucosa and grasping any muscle. We've just done a non-block resection in the cecum. If you could ignore that defect for a second because there's nothing there that needs avulsion, but we put the forceps down just so my tech grant could demonstrate that. He can very easily adjust the size of the opening of the forceps. And I know that seems very obvious to everybody, but just in case, you can adjust how open the forceps are to the size of the target tissue you're going to avulse and thereby, in some cases, reduce the risk of grabbing too much tissue, reduce the risk of muscle injury during avulsion. Secondly, you may find it valuable to rotate the forceps. Now, obviously, most forceps are not rotatable, so we're going to discuss how to do that. And I would say a small percentage of the time I feel that I want to rotate the forceps either to approach the target tissue from a different angle, maybe to get more tissue, maybe to get less tissue, or because of the curvature of the colon, we may want to approach it this way as opposed to that way to get a better grasp on the tissue. So here we are, same day, same defect that doesn't need any avulsion. And again, we've put the forceps down just to demonstrate a second technique that can be desirable during avulsion, which is to rotate them. The device is not made for rotation, but my tech grant is spinning it. He's spinning it to the left counterclockwise. The way most accessories are wired, it's easier to rotate them if you want to counterclockwise. And so you can see that slowly the orientation of the forceps is going to turn 90 degrees from where we started. And again, depending on the curvature of the bowel, the size and orientation of the piece of tissue you want to avulse, you may find this desirable. There we've achieved about a 90 degree rotation. Third, remember that tenting isn't always a pull. Sometimes it can be a lift. So when we are grasping a hold of that polyp tissue, if we're fairly unfossed to it, we may want to pull to get mechanical tension. If on the other hand, the wall is running this way and we grasp the tissue, the best approach may be to lift in order to get our mechanical tension. Fourth, remember that we're doing hot avulsion. If the metal on the forceps is touching other mucosa, it's going to burn that mucosa when you apply the electrocautery. So ideally, from the tip of the forceps back to the covering on the sheath, we want that forcep to not be touching anything except the target tissue. Finally, number five, be careful about tissue that's on top of a fold. So here the target tissue is on the tip of a fold. This is also true with snaring. The muscularis propria tends to come up closer to the surface on the top of a fold. The only time I've had a perforation just once doing hot avulsion is by coming down and grasping that, got too deep, got a hold of muscularis propria and pulled that off. Obviously, if that happens, we can close that immediately with hemostatic clips, but be cautious for that tissue that you're just staying on the edges of the target tissue, getting into the submucosa, not grasping too deeply. The final component of the process that I want to add in is the use of electrocautery and to point out that it's a very brief tap of the yellow pedal. We're using cutting current, so we are grasping the tissue already, and you can see that we're lifting it. In this case, we're tenting it away, so it's this mechanical tension that creates some of the ultimate tissue separation in addition to the electrocautery. We're lifting this tissue that is our target away, and then we're going to use the yellow pedal and just a brief tap, sometimes a couple of taps, three taps, but a lot of times just one tap with the right mechanical tension, and it will pop right off. That's what we're looking for in hot avulsion. Again, the current we'll use for hot avulsion is endocut I on the 141 setting. Next week, seeing avulsion during routine EMR on the ASGE SuTab tip of the week.

hot forceps

avulsion

colorectal EMR

thermal injury

snare tip