Today, scope rotation and fold tracking in the resection of diminutive polyps on the ASGE SUTAB tip of the week. It's widely recognized that colonoscopy is highly operative dependent and for detection we've known that since the mid-1990s, but the documentation of it for polyp resection has been more recent, starting with a CARE study in 2013, which showed a threefold variation in resection efficacy. And then in the last few years, a group of young investigators, Raj Keswani, Tanya Kaltenbach, and others have shown using formal scales for measurement of polypectomy skill that there is a threefold variation in technical competency in one of their initial studies, the range of competent resections for individual endoscopists range from 30% to 90% with no association of polypectomy competency with ADR or withdrawal time. So we want people to be good detectors and resectors. Some people are. Some people are good at one and not the other. Some people, unfortunately, not good at either. But hopefully we're entering a period where we start to assess the quality of polyp resection. These are some of the technical factors that were found to vary significantly between endoscopists when they were evaluated using one of these formal scales. This is the DAPAS, direct observation of polypectomy skills assessment tool. You can see achieving optimal position, which means putting the polyp at the five or six o'clock position in the endoscopic field, determining the full extent of the polyp, obtaining a stable endoscope position, which means you're not getting too close, not getting too far away after resection, examining the site for remnant polyp and treating any residual, placing the snare accurately, which means placing it so that there's a rim of normal mucosa around the polyp that's going to be captured and getting the appropriate amount of tissue. All were variable between endoscopists. I find that the key technical elements of DAPAS and CSPAT for the resection of small polyps and specifically talking about the resection, of course, afterwards you need to retrieve the polyp and wash and evaluate the defect. But with regard to the resection itself, the key elements are rotation to the five or six o'clock position, maintaining an optimal working distance, and then placing the snare accurately so that we get this rim of normal tissue. And today I want to focus specifically on the rotation process. Here's a diminutive polyp in the nine o'clock position. We're going to rotate it around to the five or six o'clock position. We do this because we can see it and study it better in the five or six o'clock position and we can resect it better. We can keep it under vision as we're resecting. We have better control of tissue in the five or six o'clock position because that's where the channel is on the scope. That's the reason why it's better. It's a critical skill for advanced resection, so we want to learn it early on. Here there's a small polyp up at two o'clock and we're going to rotate it over to the five or six o'clock position. Now, I will admit that I don't do this on every single small polyp depending on how much loop is in the scope and where it is. If I can approach it in a different angle, I do sometimes. But I think oftentimes people will try too long to remove a diminutive polyp that's really in a poor position. And so moving it to this position is a critical skill. Here's a small lesion up at 11 or 12 o'clock and we're going to rotate it down to five or six o'clock. And I'm initially putting the snare out and we're just tracking the contiguous folds, which are what I'm going to watch as I'm rotating. But I was mentioning that this is a critical skill for the resection of large lesions. You need them down in the five or six o'clock position to see them well, to control the tissue well, to use really precise movements. But it's actually a bit easier for large lesions because they're easy to find again once you've rotated. But I think diminutive lesions, one of the issues that happens that I see with trainees is that as they're rotating, the scope tends to move either into the colon quite a bit or they fall back some during that rotation process. And so are there any tricks or tools that we can use to prevent that from happening? Here's a diminutive polyp at 12 o'clock and I'm using the snare tip right now to trace the fold that polyp is contiguous with. I've drawn a yellow line here on the fold that I was just tracing with the tip of the snare. That line is contiguous with the polyp and it comes around to where the five or six o'clock position is. And we're going to get the polyp in the five or six o'clock position by torquing either counterclockwise or clockwise, depending on which way is shorter. While we're doing that, we'll also be turning the controls either right or left. And during that time, we might lose sight of this diminutive polyp. But if we keep the fold in view or almost in view the entire time, then when we get torqued around enough, the polyp should be there for us. And I call this fold tracking because the fold basically will guide us to the polyp. And if we keep that fold in view, we won't go in too far. We won't go up proximal to the polyp. We won't fall distal during that rotation process. So here's that same polyp up in the 12 o'clock position. We are tracing that fold with the tip of the snare, that fold that is contiguous with the polyp. Right now we can't see the polyp. But we're keeping that same fold in view. This is the process of fold tracking. Now the polyp is back in view. It's getting down around to the 5 o'clock position, the correct position for removal. So this process of fold tracking will help you to stay in the correct in-out position in the colon. Here's a polyp at 11 o'clock that's just distal to a haustral fold. And we're just taking the tip of the snare and tracing that haustral fold that's going to be our marker as we rotate. Here's a yellow line that's on this haustral fold that will be our marker as we rotate. And again, the polyp doesn't have to be on the fold that we're using. We just have to know the relationship of the polyp to the fold, this fold that is serving as our marker as we rotate. So when we first see this diminutive polyp up at 11 o'clock, we should note that it's a few millimeters distal to this haustral fold. And then we trace the haustral fold with the snare tip. And then as we rotate, we're rotating clockwise. We know that when we get around far enough, we will find that same diminutive polyp, just a few millimeters distal to this haustral fold that we've tracked around during the rotation process. We track the fold when we lost sight of the polyp. It's a very useful way of keeping track of diminutive polyps during rotation. Again, they're easier to lose than large polyps. Large polyps, of course, are easier to find again. Here's a diminutive polyp up at 10 o'clock. And I just want to make the point that what we track, it doesn't have to be a fold. It can be a spot of blood or a red mark, a distinct area of mucosa. So in this case, if we draw a line from the polyp over to this blotch of yellowish mucosa on the opposite wall that is circled, if we keep that blotch, that yellow mucosa in view or even partly in view as we rotate, then we should end up in the right place. Here's our little polyp again, and we're going to take the snare tip and draw a line over to that yellow mucosa. I don't usually do that, but I think it's instructive for understanding the thought process. So as we rotate clockwise, we are keeping that yellow mucosa in view. We get around, there's the polyp, same relationship it was to the yellow mucosa. So the yellow mucosa served as a marker, keeping us from falling back too far while we rotated. We still got to do all the good resection components. We got to keep a good working distance, keep the lesion down at five or six o'clock, place the snare accurately and resect with a nice margin. I'm sure you've got the idea now of fold tracking, but I just want to show one more example of the value of it because this is a little diminutive polyp at nine o'clock and I fold tracked this, but despite that still lost track of it. But if you keep that marker fold in view and keep searching in that area, the polyp has got to be there. So we're initially taking the tip of the snare and just tracing down along a household fold that we're going to use during rotation. So we're all on the same page. There's a white circle around the little polyp and a yellow line along the fold we'll use for tracking. So the snare tip was just on that fold that we're going to track. Now we're rotating to the right. There's the fold. We can follow it down to six o'clock. Things have collapsed a little bit, so it's a little bit harder to see. I don't see the polyp right at the moment, but we know it's got to be between these two household folds. The one down at the right was the one we were tracking. I do see just the polyp. I didn't actually see it at the time. You can see me wandering off there, but I need to stay in this area because there is the polyp and now we've got it in position. So fold tracking allowed us to basically know, even though we couldn't see it when we rotated, it's got to be in the vicinity. Next week, management of immediate hemorrhage after cold snaring on the ASGE SuTab tip of the week.

scope rotation

fold tracking

resection

diminutive polyps

colonoscopy