So, this talk is on EMR with electrocautery, and we'll talk about cautery settings, avulsion, and SNARE-TIP soft coagulation. Can you see my screen? Yes. Yes, Amit. You're coming. Okay. So, EMR, endoscopic mucosal dissection, is the standard of care for large benign polyps, and it's been shown to be safer than surgical dissection with very low morbidity and mortality compared to surgery. Perforation is the main risk that we worry about. That's about 1.5% with 6.5% bleeding rate. Mortality is almost negligible. It has been shown in multiple studies to be more cost-effective than surgery, and the goal of EMR is to remove the entire lesion safely, completely, and efficiently. So, what are things we should not be doing? And I want to emphasize this very much because this is something that we see all the time being done, and as gastroenterologists, we should not be doing some of these things, which is not to refer benign-appearing polyps to surgery. I can't tell you how amazed I am that still, after so many years of successfully resecting these polyps endoscopically, experienced gastroenterologists are still sending benign-appearing polyps to surgery. Sometimes it's so embarrassing that the surgeons will call me to see if, you know, they've been sent this patient over, and can I remove the polyp, and you look at the polyp picture and it looks like a benign polyp. So, please do not refer these to surgery. Do not attempt removing lesions with features of invasive cancer, and that is where it's important to learn these patterns, these patterns that we see on chromoendoscopy to identify invasive cancer. If you have a benign lesion, don't attempt to remove it. If you don't feel competent to remove the entire lesion in one attempt, there's no harm in accepting that this is beyond your capacity and send it to an expert. You do more disservice to the patient by making a half-hearted attempt at removing these lesions and making it more difficult for the next person to remove it because of the underlying scarring and whatnot. Also, if you feel that, okay, you found a lesion unexpectedly, you're in a busy day of screening colonoscopies in a surgery center, you don't have enough time, reschedule the patient. You come out of the procedure, explain to the patient. Most or majority of the times, the patients actually appreciate that, yes, you did the right thing, you did the safe thing, reschedule it with more time on your hand in the hospital to do the EMR. Also, don't biopsy benign appearing lesions. There's no reason to biopsy. If you recognize the pattern and it's nice type 2 pattern, it's a lateral spreading tumor granular type, there is absolutely no reason to go ahead and aggressively biopsying this because you'll just cause more scarring and make it difficult for the next person to remove it. And also about tattooing, please do not tattoo close to the lesion or under the lesion or if the lesion in certain clear areas like the cecum, and there's absolutely no reason to tattoo these, you'll just cause some mucosal fibrosis and make the subsequent resection more difficult. What you need when you're dealing with these polyps is good technique, adequate time, all the tools necessary, a good team with you, with your techs and nurses, and above all a good temperament. You have to have the tenacity, the temperament to take care of these lesions because they will be hard. They will require a lot of patience and determination to take care of them. So you have to have the temperament to do that. What are the tools? This is the laundry list. You should have high definition scopes with the ability to perform electronic chromoendoscopy. I always use a distal attachment or a cap, it really helps me during my EMRs. You have to use CO2, that goes without saying now. Injection needle, different solutions to raise the polyps. You could use saline or heta starch or hydroxyethyl starch mixed with methylene blue or indigo carmine. Now we have these commercially available ones that you can use, snares of different shapes and sizes, coag grasper forceps for control of bleeding, hot biopsy forceps has come back in the vogue because of the hot avulsion that we'll discuss, APC clips and microprocessor controlled electrosurgical generators. What are the basic points in technique? You have to assess the lesion and characterizes. We talked about this, Tony talked about it in detail, have a stable scope position, bring the lesion in ideal position and usually it's in the lower quadrant and also anti-gravity. You should be confident and competent in doing retroflexion in the ascending colon when you are dealing with ascending colon polyps. Create an adequate submucosal lift if you're doing the conventional EMR. You have to have a meticulous resection technique in which you are removing portions, contiguous portions of the polyp without leaving behind islands or ridges of adenoma in between and also clear the margins. After you resect the lesion, you assess the base carefully as well as the margins and look for any residual adenoma before you try to do anything else. So once you've removed all what you can, if there is any remaining, then you try to remove those areas with avulsion or finally ablate. Margin treatment is the standard of care, either with snare tip soft coagulation or APC, we'll discuss that. And large lesions on the right side, you should close the defects with clips. For lesion assessment and characterization, a couple of things that I've learned over time is I try to get the colored images of the polyp if they are referred to me because that helps me in planning my resection and determining how much time I need, so on and so forth. When you start the procedure, you got to the polyp, you spend some time inspecting before you start resection. Have a plan in mind after you inspect the polyp as to how you'll approach it. Assess the size, the extent of the lesion, as well as the accessibility, the morphology, how the surface looks like, examine it with electronic chromoendoscopy. If you feel there is evidence of invasive cancer, just biopsy and tattoo. And then you also obviously have to decide, can you remove it in one attempt, and if you think you can't, then you refer. So the five things you want in your description in the report is the size, location, Paris classification, whether the surface is granular, non-granular, and what is the NICE or the JANET classification. So I'll go over some of these, some of videos that will basically reiterate and discuss some of these techniques that I talked about. So this is a distal rectal polyp. As you can see, it's a flat polyp Paris type 2A. It's lateral spreading tumor granular type. I'm looking at it. I'm not seeing any dominant nodule or any areas of concern under NBI. So this is basically the risk of any invasive cancer, and this is practically zero. And these are the ones you should never, ever send to surgery, regardless of how big they are. So we'll try to raise this. I'm putting the needle in. There are two ways of injecting. Either you can pierce the wall a little tangentially, like Dr. Rex was explaining, and then inject. And if you see a bulge, then you are in the submucosal space. If you don't see a bulge, that means you've gotten deeper to the submucosa, and then you pull the needle out slowly till you see the bulge. Or the other way is you start injecting, and then you pierce the wall, and you stop as soon as you see the bulge. The reason why you have the blue color is it not only highlights the margins of the polyp, but also after you resect, you can see the base clearly and look for any evidence of muscle injury. So clear demarcation of the edges, as well as evaluating the base for any muscle injury, that is how the dye helps. Here, I'm trying to make sure that I'm taking contiguous portions of the polyp without leaving behind any ridges of tissue in between. So I'm moving my snare, and I'm trying to overlap as much as possible, and also trying to take a little bit of a normal margin around the polyp so that there's nothing remaining behind because sometimes if you leave behind small ridges or islands of tissue, it becomes very difficult to remove them at the end. So here, I'm just working in that submucosal plane, trying to push my snare in. One technique that you can do if you get concerned that you've got too much of tissue is after you close, you release the pressure, I ask your tech to open the snare a little bit. So if you're concerned that you've grabbed the muscular spropria in the initial closure, it'll slip out when you loosen the grip of the snare, but you have to do it very slightly. You don't want the normal adenomatous tissue to slip out from the grip. So here, I'm again, working on the other area of the polyp, and in these large polyps, you don't have to raise the entire polyp at one go. So here, as you can see, I'm working patiently. I've removed one portion of the polyp after sequential injection and snare resections. Now I'm working on the other part of the polyp, and then you just keep going from one side to the other in a systematic fashion. And that is the game plan that you have to form when you look at this polyp while you're inspecting it. That's very important to have a systematic way of doing this. It's not like a Brownian motion that you go one way or the other and just take out portions that you feel are easy to take out. You've got to be meticulous, methodical, and patiently work from one edge of the polyp to the other. Now we've completed the resection. You look at the base. Then we go for ablating the margins, which is the standard of care, and we use snare tip here with soft coagulation, and we'll talk about the settings. So you go around just touching the edges, and I try to touch the inner side of the edge here because that's where there will be any, if there is any islands or adenomatous crypts remaining, that's where it will be. So try to touch the medial edge of the margin, which is closer to the resection bed, and then you go around. And sometimes I just do it twice. It's very easy. You just have to have good control of the snare when you're doing this. Moving on to a different type of polyp, different situation. Different type of polyp, but in the cecum now. Again, this should also not be alarming. You look at, this is a pretty large lateral spreading tumor, granular type, Paris type 2A, nice type 2 pattern, very likely to be benign, chances of invasive cancer almost zero, never should be sent to surgery regardless of the size. Again, you form a plan in mind. Here I'm trying to resect from the portion which is closer to the IC valve because that's a little tougher to resect because of the location. And sometimes in these patients, you might have to move the patient's position to get a better view. That's also an option to do, but here we got a good view. I've injected one portion and I'm using a snare. Now my go-to snares in these situations is not more than two centimeters because I'm a little uncomfortable removing big pieces in the right colon. So this is like a duckbill snare, which is where you can use oval, round, whatever is your snare of choice, but again, the key here is to work methodically from one portion, one side of the polyp, overlapping pieces, not leaving behind ridges of tissue in between and slowly injecting, resecting, injecting, resecting. That's the pattern that you have to follow. So as you can see, you have to have enough time. This cannot be done in a 10 minute, 15 minute time slot that you may have for a screening or a half an hour time slot that you may have screening colonoscopy. And this is also the reason why seeing a picture of the polyp from the referring is also helpful for me to plan how much time I need on the schedule for this. So again, as you work along from one side to the other, you can see that this nice base clearly tells you this is all submucosa. There is no muscle injury here. I don't see any residual adenomatous tissue that I may have to deal with later. I'm trying to dig the snare in a little bit, just trying to grasp as much tissue as I can. I have a good lift. So that gives me the sense of confidence that I'm not going to damage the muscular spropia. Here, there's a little bit of island remaining here, which I'll continue to remove. We are coming towards the end of the polyp. As you can see, it's a wide defect in the cecum. But again, these are low risk polyps. They should be tackled with endoscopic resection and should not be sent to surgery. And I'll keep repeating that multiple times because I still feel that, you know, many of these polyps are still being sent by a gastroenterologist to the surgeons. And I mean, before you know, a portion of the colon is taken out. So you have to educate your surgeon also that you can do this and gain their confidence. And that is the best thing for the patient. So here we have resected the lesion. Then we'll go around ablating the margin with a snare tip, with snare tip soft coagulation. And so moving on to a little more bulkier polyps. So this is more like a sessile polyp. It's present in the ascending colon. Again, you inspect this with narrowband imaging. Make sure that there is no evidence of any concerning feature for invasive cancer. Spend a little bit of time, then you start resecting it. So first step is injection. I try to, in these lesions, which are wrapped over folds, I try to inject the proximal side of the lesion. Same technique. I punctured the wall, then start injecting, and then I usually withdraw. You could do the other way of starting the injection and then puncturing and then stop as soon as you see the bulge. The advantage of injecting on the proximal side is it flips the lesion towards you. So it makes it more accessible. If you inject on the distal side or the anal side of the lesion, sometimes it can flop over the fold and make it more difficult to visualize. So here I could have done a retroflexion to view it, but since I had good confidence with using the cap that I was seeing the entire lesion, I did not feel the need to retroflex. So after raising it adequately, you saw that there's a good lift all around. We start from, again, one side, one end of the polyp, taking my time, trying to entrap as much tissue as I can with this Doug Bill snare, making sure I get the margin. Here you can see a little bit of a margin here, and then I squeeze. I got enough, a lot of tissue. So sometimes I'll just release the snare a little bit, ask my tech to release it a little bit. Just give me that level of comfort that I'm not entrapping the muscularis propria, and then I cut. And then you inspect the base, make sure that there's no muscle injury, and then systematically go to the next portion. And then obviously, similarly, in four pieces, we'll be able to remove this entire lesion safely, and we'll have less issues with residual at the margins or the base if you follow the these simple techniques. So here I think we had this lesion, we're now doing snare tip soft coagulation. Again the same way, you use the tip of the snare, burn the middle side, the edge, especially the medial side of it or the inner side of it, so that there is less chances of residual or recurrence later on. So this is another example, a larger polyp. So this is a little different from the previous one in the sense that this was deceptively large, and I mean also deceptively small. When I'm inspecting it, I knew that I was not seeing the entire lesion clearly. So what do you do? This is the right colon. I've examined it. Whatever I could see, I did not see any evidence of invasive cancer. It's all nice type II pattern, rather bulky. So that means it should be removed endoscopically. I do the retroflexion maneuver like we discussed, and you'll see after I retroflex how much more of the lesion can I clearly see. Here I'm retroflexed, and I'm pulling out now slowly. You do this gently, and now you can see a fair amount of lesion that I had not been able to visualize is visible now. Not only is it good for visualization, but also for injection. So I'm keeping myself in the retroflex position. So this is, I'm still in the retroflex position, and I'm going to inject on the sacral side of the lesion and see if I can push it anally. So basically, I get into the submucosal plane, I'm injecting, and here I'm injecting aggressively. I keep on injecting the fluid, and you can see that the lesion is slowly flipping over towards the anal side. And once you get into the plane, submucosal plane, you stay there. And after this, I undo the retroflexion, and now you'll see a different view of the lesion. Now you can clearly see the proximal edge of this lesion, which was not clearly seen prior to the injection. And now it's the same process. You've raised it, you remove the raised portion starting from one side and systematically working towards the other side. And then whatever portion needs to be raised again, you further inject and raise. So it is the same process, nothing different. So we've started from the right-hand side, and we slowly will go towards the left-hand side, and this is only the proximal portion of the lesion. Then we inject more as we go along, because this lesion is a big one, and we'll need a sequential injections and then resection. So it's difficult to raise this entire lesion with just one series of injection and then remove it. I usually end up removing portions of it, injecting portions, and then removing those portions versus injecting the whole lesion at one go. Because sometimes if you inject too much, it makes your resection more difficult because of space limitations, et cetera. So here, again, we'll just, in the interest of time, go forward. So I'm just continuing to use the same principle, getting big pieces out, make sure we are overlapping, getting a little bit of extra margin if you can, which should be done so that there's less recurrence. When you go back here, we're coming towards the last portion of the lesion here. I'm trying to get a little bit of extra mucosa there, and that is the advantage of having a good submucosal lift, that you can be aggressive and you shouldn't be very fearful if you have a good submucosal lift that you will perforate or cause any injury. It gives you that level of comfort that you can aggressively remove normal mucosa because that's been lifted. So here, the procedure is done, and then you start ablating, and then Dr. Rex will talk about the clipping, which I had to clip this lesion also, which we'll discuss in the next lecture. So these are the basic principles of conventional EMR. Now, what about underwater EMR? So this is an interesting concept that started a few years ago, where the basic thing is that when you insufflate gas, you distend the lumen of the colon, and it flattens the folds and actually thins the colonic wall. Now, if you fill the lumen with saline, what happens is the folds become more prominent, and this is because of the involution of the mucosa and the submucosa that floats away from the muscularis propria towards the center of the lumen. So basically, it's like a natural way of separating the mucosa and the submucosa from the muscularis propria, exactly what we do by a submucosal injection. So this is just by filling, suctioning the air out, filling the lumen with water does this, or saline does this. So what happens as a result of this is, if there's a mucosal lesion that you have to remove, it's automatically separated from the muscularis propria, therefore resecting it, you can resect it without the risk of causing muscle injury. So there's some caveats to this, you have to have a good bowel preparation, because you're filling it with water, here's a polyp, which actually this polyp was referred by a gastroenterologist to a surgeon for left-sided heavy colectomy. It's a sigmoid colon polyp, and the surgeon called me to see if I could resect it endoscopically. So you can imagine, it's not a big polyp, it didn't take me too long to remove it, inspected it, filled the lumen with water, suctioned the air out, filled the lumen with water. Sometimes you can mark the edges with cautery, but in this case, this was pretty well visible, so I did not. I mean, and you can use water or saline, it's recommended that you use saline for better conduction, but I have sometimes forgotten that and filled it with water and get the same effect. So here, you get the snare around it, and you have to be a little careful during the last step, you want to torque and get the snare around and ensure that you're getting the entire polyp if you're going for an on-block resection. So here, sometimes I move the snare back and forth to coax all the tissue into the snare, and then I'm closing the snare tightly, then a little bit of suction might be helpful too, but I don't advise too much of suctioning when you're getting the polyp into the snare, and then you use electrocautery. Now this, I use endocut, the different types of currents have been recommended. So here is an on block resection of like a two, two and a half centimeter polyp, clear edges, base, you inspect the base. There is no obvious muscle injury, no bleeding, and it's a faster and efficient way of removing polyps that are two to three centimeters in size on block, you need less accessories, less cost. And overall a good technique, you just have to become comfortable in working under the water because that is something we don't usually do when we're resecting polyps. So what is the data? If you come, if meta-analysis compared this underwater with conventional and it actually worked out better in terms of on block resection rates, overall, as well as for polyps greater than two centimeter, rates of recurrence was also less. I mean, with underwater EMR it was 6.8% versus 19% for conventional EMR, and equal number of complications, so no difference in there. Another major difference was shorter resection times, which was at least five minutes less than what we saw with conventional EMR. There are some limitations, though, it doesn't work in every case. If you have a poor or suboptimal bowel preparation, it will be very difficult to visualize so sometimes strong contractions of the colon can cause problems. Another point here is that if you have a very bulky large polyp, and you can't remove it in one piece and you have to piecemeal it underwater, any bleeding after one or two resections can make visualization difficult and the whole procedure becomes more difficult because then you have to suction everything out, clean it and then fill it up with water. So I feel it's not very ideal for large bulky sessile polyps that can't either be removed on block or in one or two pieces. Lack of dye, we're not using any blue dye. So we talked about the advantages of the blue color. Here, because we're not using the blue dye, sometimes the margins can be less obvious or less clear, the margins of the polyp. Also, because there is no blue color in the base, after the resection, it might be difficult to detect any residual polyp tissue or muscle injury. So those are some minor points that go against underwater EMR. There is no non lifting sign because you're not injecting any fluid so I mean if there is invasive cancer which which could be missed also so you have to really rely on your endoscopic features. When you're assessing the polyp, and obviously if you have a perforation and there was stool and fluid in the colon, it'll create a chance to leak out of the perforation, if you're doing underwater EMR so that's another thing to be concerned about. The bulk prep is not good. But I feel it is good for lesions that are two to four centimeters in size for on block resection, especially good for non granular flat lesions because they really float up well. And these are the ones sometimes you have difficulty raising with submucosal injections so any Paris type 2A non granular lesions are good candidates for underwater EMR. What about the difficult non lifting portions of polyps. Why does this happen I mean there's several reasons for this, you can have underlying scarring or fibrosis, you can have areas of previous biopsies that can cause scarring previous attempted underlying tattoo and invasive cancer. And so the techniques that we have for these card down non lifting portions are hot avulsion, cap suction, the cap, the cold avulsion with native soft coagulation, underwater EMR, and the full thickness resection device. So, couple of quick videos on this so this is hot avulsion technique. Here is a recurrent polyp you can see the tattoo mark we removed most of it, the small amount remaining. So we take the hot biopsy forceps, and you stay close to the polyp. And then you grab it with the, with the force of the remaining or the residual or the admitted issue, then you tend up and pull it towards you, while pressing the yellow pedal on on the gender of the generator. So you're using an endocard eye for this. And basically you're peeling off the adenomatous tissue so again staying close to the polyp remain the scarred down portion. Pulling the forcep, pushing it out grabbing the tissue, and then peeling it off by just pulling this the force of towards you while pressing the pedal. So it helps to peel off these scarred down fibrotic portions and and and get your completed section. So, what is the data, there's one study that showed that if for visible residual neoplasia, after you've removed whatever you could with snare cautery. If, if you treated that with APC, or you treated it with hot avulsion, the outcomes were better with hot avulsion, in this situation was 10% compared to 59% when you used APC so something to to consider for small amount of scarred residual remaining polyp tissue at the base of the defect. The other technique which I really like is the cap suction technique I think Dr. X mentioned about this, this is another residual recurrent adenoma referred to me removed, we removed whatever we could with snare cautery. And you have this portion, which would not raise. So with the cap suction technique you stay close to the polyp, you open the snare, you have the cap at the end of the scope, and you suction. So what you're essentially doing is you're bringing this polyp tissue into the compartment which is between the tip of the cap and the tip of the snare. And because the snare, the cap is protruding about four millimeters beyond the tip there's only limited amount of tissue that you can get into this, which protects against that the perceived risk of perforation so you suction. And as soon as after you suction you ask your technician to close the snare, and you cut. Sometimes you can even cut blindly. Other times if you have too much tissue you can push the snare out to see what you got and then cut so again I'm staying very close to the tissue, using the cap suctioning the tissue into the cap and then closing the snare to cut and remove the scar. You can see there's so much of scarring here with all the tattoo and so this is kind of a situation that sometimes needs either avulsion or the cap suction technique to remove this type of tissue. What are the data, there's recent study that showed for benign non lifting policy pretty successful I mean the in 67% of these situations they were able to remove the entire polyp using the cap suction technique and in these difficult polyps that is the risk was a little higher but not terrible and more importantly all these recurrences were treated endoscopically, and the deep mural, which is the main risk perceived risk is okay I'm suctioning it into the cap, what if I'm going to get the muscular muscular proper there's no perforation the deep mural injury were all treated with clips so it's very safe you just have to have that level of comfort that, and the confidence to be able to do it. Cold avulsion and snare tip soft coagulation so Australian group has proposed this, this was a recurrent adenoma referred to me quite a lot of tissue here so we removed a lot of it with routine conventional snare cautery then you come to this scarred down portion which was difficult to snare. So here is the technique is basically as the name suggests, you call the wall so you use a regular biopsy force it, and you just peel start peeling the, the tissue out the adenomatous tissue out. I don't prefer using this because as you can see it starts bleeding in hot avulsion there is no bleeding pretty much in this technique there is bleeding, and that sometimes messes up your visualization but nevertheless, it's safe, because you're not using any heat, but you have to follow it up with with ablation using the snare tip and soft coagulation so you remove as much as you can, with the biopsy force up and and and and waltzing whatever tissue you can grab. Sometimes it becomes difficult to grasp the tissue because you're not using any heat also so and and also because of the fibrosis and the biopsy force of can slip. Here we've removed whatever we can then be using the snare tip to gently ablate the base, so that if there's any residual tissue that we could not a waltz with the biopsy force that will destroy it with with soft coagulation so obviously doesn't look as you would want to be but this is the best you can do in these tough situations where you have a densely scarred down residual adenomas so this is the technique. The Australian group did most of has done most of the work and this published the study where they use this for previously attempted non lifting lesions as well as for naive non lifting lesions and they had good success, although every time they went to surgery there was higher rates of recurrence in these situations, compared to the lifting lesions which is expected, but the risk of referral to surgery was no different they had hardly had to refer any patient to surgery for unsuccessful therapy and they call this as a safe effective technique, and that safe surgery and majority of the of the of the non lifting lesions. So that brings us to what are what are the electro country settings and generator so all. We all should be using microprocessor controlled electrosurgical generators what did basically means is that the integrated microprocessor reads the tissue in milliseconds. And because of this, the power fluctuates, according to the needs of the tissue, but the voltage remains constant and what what we need to understand is the, the thermal injury depends more on the voltage than the power so because the voltage remains constant. The thermal effects, and there are more predictable and there is less thermal injury with these generators. Now quick word about what is cutting and what is coagulation current for in cutting current the voltage goes above to 200 volts, which is high current density the temperature in the cells rises to more than hundred degrees centigrade. As a result of this the cellular water heats up rapidly and this results in the cells, boiling and bursting, and this causes cutting or transacting of the tissue. Whereas, in contrast, with coagulation current you have low lower voltage, lower current density the temperature doesn't go that high it goes maximum between 60 to 100. And as a result of this, the cells heat more slowly, and they dry up the desiccate and they shrink. And this is what results in either plotting the blood vessels or ablation of of the tissue. So the yellow cut because this is term we use all the time, it is a current which is alternating cutting and coagulation cycle so the yellow is the, the cutting cycle and the blue is the coagulation cycle. And now, on top of that, the cutting and the coagulation cycles can be adjusted to minimize the risk of bleeding, perforation and deep thermal injury and you'll hear these words effect, duration and interval. Effect goes from one to four. And as the effect increases the cut decreases so lower the effect higher is the cutting and and vice versa. For duration, you have one to four, as the duration goes up the duration of the cutting cycle increases, and then you have interval which is one to 10, which is as the interval goes up the duration between the cutting cycle decreases. So those are the three things that you have. Now what are the settings we use for EMR, either use forced coagulation with effect to maximum work is 25 or endocut Q, effect to duration one interval is four, other settings are three, one, six. For underwater EMR what was initially described was autocut effect five maximum watt 80, but different other currents have been used and I use endocut Q routinely I don't change it from what I use for conventional EMR. For hot avulsion, endocut I, effect one duration four and interval one. Snare tip soft coagulation for either treating the margin or the coag grasper for the bleeding vessels we use soft coagulation. This is effect four to five, and the maximum wattage is 80 watts, and then APC if you're using APC for margin treatment, then the wattage is 25 to 30 watts, and the flow rate is 0.8 to one liters. What is the data? Very, very limited data. This is the secondary analysis of the CLIP trial where we found that polyps that were resected by endocut versus forced coagulation, the rate of serious adverse effects was similar. The polyp recurrence rate was also similar. But if you look at the details here, intraprocedural bleeding was higher with endocut, 17% versus 11%. Now, you could argue does it really matter? It could matter, it might make your resection more difficult. There is some data to suggest that intraprocedural bleeding leads to higher recurrence rates. Perforations, although not statistically different, were numerically higher in the patients who got endocut or resection with endocut versus forced coagulation. So that's pretty much the only good study comparing the two. Now, I wanted to talk about cold-snare piecemeal EMR for lesions greater than 20 millimeters. So Dr. Rex talked about lesions less than 20 millimeters and SSLs of all sizes where cold-snare EMR can be done. But what about adenomas and different types of lesions morphologically? Initially, the study showed that this was very effective, and not only for good low recurrence rate, but also for decreased post-polypectomy bleeding, which is the main advantage of this technique using cold-snare piecemeal EMR. So this Australian study actually showed that even the recurrence rate was very low. And the intraprocedural bleeding was low and post-EMR bleeding was extremely low. But if you look at the study, the caveat was that they had very high rates of SSLs. Two-thirds of the lesions here were SSLs, and they excluded bulky lesions, SSI lesions, peduncleated lesions, and any lesions that might have either invasive cancer or concerning for invasive cancer. So if you look at the most recent large, one of the largest study, I think it might be the largest one that we have, which is retrospective, in which all types of lesions were included, the recurrence rate was an astonishing 35%. And what were the predictors? The age, the polyp size, and the histology. In fact, as you go up on the size, if you go up to greater than 50 millimeters in size, the recurrence rate is almost 75 to 80%. So this tells us that if you have unselected lesions, which are more than 20, 30 millimeters in size, the risk of recurrence will be very high. And then we have this data that was presented at DDW. I took the liberty of showing the preliminary results. So the result that will be shown is a randomized control trial, 10 centers, comparing cold versus hot EMR. Serious adverse events were higher with the hot EMR, mainly in the form of bleeding and some more perforation. But the recurrence rate was much higher, significantly higher with cold EMR compared to hot EMR. So it's a good technique for SSLs of any size. And for adenomas, I feel it's a good technique for Paris type 2A lesions that are lateral spreading tumor granulotype that have low bulk, not bulky, and the risk of invasive cancer or advanced histology is very low. So what is the technique? You've seen this, Dr. Rex showed it for large SSL. This is a Paris type 2A lateral spreading tumor granulotype in the right colon with the risk of bleeding is also higher. So one of the candidates that are dealt well with cold SNARE piecemeal EMR, the difference here for me is that I usually put some epinephrine in the injected compared to conventional EMR in which I don't. Here we are raising the lesion. One thing you can do is, there were some questions in the chat box that you could, if there's benign lesions, you can inject through the lesion. There's no reason to worry about any dissemination of adenomatous tissue here. Again, after raising the lesion, the same concept, you try to start from one side, get some normal margin, and try to overlap as much as possible. Here, because the plane of resection is superficial, you have to really be aggressive with pushing the SNARE and kind of almost digging the sheet inwards and taking your big dial away from you to get as much tissue as possible. Otherwise, if you don't do that, then you risk leaving behind polyp tissue. So here again, as we go along, systematically from one side of the lesion to the other, the reason to put the epinephrine here is otherwise there will be more intra-procedural bleeding, which will make your resection a little more cumbersome. So that's the reason I don't think so. It impacts post-procedural bleeding or delayed bleeding. So here we are coming towards the end of the lesion. Exactly the same technique. I don't think there is much difference in the technique if you're dealing with an SSL versus an adenoma, except that sometimes the bulk of the tissue that you get in a SNARE might be a little more and can be difficult to resect. So here you can see in the last part I got a little greedy. It was difficult to cut out, so I asked my tech to open and close, and that wasn't working. So I gently tugged it against and amputated it against the scope. There's a little bit of a submucosal cord here. It's no big deal. And after this you inspect. That's the key here, is to inspect and do some cleaning up. If you have to resect a little bit of normal mucosa along the margins, it's very low risk. There's absolutely no risk of bleeding or causing any harm, but do inspect. That is a very important part of the resection is good inspection of the margins, as well as the base here. This is my OCD kicking in. I'm just trying to shave a little bit of normal mucosa. You may want to do it, you may not, but it doesn't harm. It's very safe and it's very quick. So this is cold SNARE EMR for adenomas. So, quick word about on block resections as I try to wrap this talk up. We've discussed this. This is recommended for those lesions with the suspicion of superficial invasive cancer because once you resect this on block and you place it on a wax mold and pin the edges, it's almost like a surgical specimen and the pathologist can make vertical sections and give you exact details of any invasive cancer as to what's the depth, whether there's any lymphovascular invasion, what is the tumor budding, etc. So, the lesions that are candidates for this is first of all they should not have any evidence of advanced cancer. JNET type 2b which is irregular vascular pattern, lateral spreading tumor granular type with a dominant nodule. So you have a large lesion but a big dominant nodule, possibly if it's more than 10 millimeters in size, that harbors, there's a higher chance of harboring invasive cancer. For the non-granular lesions, either they are sessile or they are flat with pseudodepression. Increasing size increases the risk of having invasive cancer, especially in the rectosigmoid location with any of these features. And this is the term that we use, covert invasive cancer, that when you inspect the lesion based on the nice pattern, you don't feel that this is nice type 3, but there are certain other morphological patterns that predict that this might have cancer and this is what we call polyps with covert invasive cancer. So, if you do it for polyps 2 centimeters in size in the right colon, I think conventional EMR will work just fine. Up to 2.5 centimeters in the left colon. For up to 2 centimeters, a couple of other options is full thickness resection device and tip in EMR. Underwater EMR can work well for up to 3 centimeters. For 3 centimeters or more, either hybrid ESD or ESD. Hybrid ESD is basically making a circumferential incision around the polyp and then grabbing it with a snare that can be done for up to 3 centimeters and larger ones with ESD. So, quick video. This was an interesting one that sometimes you're surprised. This is a patient I scheduled for EMR in a half an hour block, 45 minute block. Looks, just by looking at it, it appears to be a lateral spreading tumor granular type. No big deal, we'll take it out. But you look at, you have to spend some time. So, we start looking at with NBI and then I come across this area that started bothering me. So, you can see this nice type 2 pattern all around, and there's a central area where you almost lose the pattern. So, this is always worrisome. Whenever you see, and this is the reason why you have to inspect these lesions very carefully, give it some time. So, I'm almost tempted to call this either genotype 2B, which is irregular or nice type 3. So, the plan was here to either do ESD or do on block resection. So, I resected the portion around this area, and then I, after raising it and also submerging it with water, I removed it in one piece on block, this portion only. So in theory, it's a piecemeal section, but the worrisome area was removed in one piece. And then I placed it on a wax mold, pinned the edges and instructed my pathologist, sent it separately from the other pieces. And also in my note, instructed the pathologist and sometimes I'll call the pathology department and talk to them also, talk to one of my colleagues who have good working relationship with this, this is what I want. So here I'm grabbing this big piece with the snare and trying to remove it in one piece so that I can send it for more, you know, it's not as good as ESD, I completely agree with that. But this is, once you're committed to EMR, this is the next best option to do. So here I've gotten the whole thing and I'm cutting it. As you can see, it's taking a little more time to cut, which is also a little concerning. Here, then you look at the base, it's almost like a type one versus type two muscle injury. You can see a little bit of muscle here, but there's no hole, there's no, it's not three, four or five. And you place it, you place the lesion on a wax mold and you send it. And actually it was interesting that as we expected, it showed superficially invasive cancer in the background of tubular venous adenoma, deep and the lateral margins were free of cancer. The depth of invasion into the submucosa was 300 microns. It was moderately differentiated, no lymphovascular invasion and low tumor budding. So all good prognostic features. So then you have to have a discussion. This is not something that you can just send a letter to the patient. I bring these patients back to clinic, sit down with them face-to-face, discuss all this, and then help them make a decision, which in his case was, we'll just continue surveillance. Now, quick word about tipping EMR. This is a newer technique described in Japan. Basically we raise the lesion with submucosal injection of fluid, make a small incision with the tip of the snare on the sacral side of the lesion. And we impact the snare in this divot that we have created and then open it. And this helps to get the snare all around the polyp because you can actually push the sheath of the snare and make the snare wider in diameter and grab the whole polyp. And has been shown in meta-analysis to have a higher on-block resection rate as well as higher complete resection rate compared to conventional EMR. So another way of ensuring on-block resection. So to conclude, EMR is the standard of care for large benign polyps. You should follow the do's and don'ts that we discuss. And please, please do not send benign looking polyps to surgery. Always have a go-to person either in your practice or in your area to take care of these patients. You have to have good technique, ample amount of time, all the tools necessary, a good team and good temperament to deal with these lesions. Underwater EMR and cold snare EMR are good options for select lesions. You should know your electrosurgical generator settings for different actions that you might have to institute during the procedure. Margin treatment is necessary, is standard of care if you're using snare cautery. For fibrotic non-lifting portions, there are different techniques, cap suction, cast or hot avulsion. And you should identify lesions that need on-block resection and then treat them appropriately. I think that's it. Well, that was fabulous. That was a fabulous review, Amit. There are some questions that I think we should, we should try to clarify. You know, questions about snares. My sense is that for EMR, we wanna have stiff snares. We talked a little bit about, you know, for conventional EMR, being a little bit careful about snare size, really big snares, may be more likely to grab the mucosa. Oftentimes with on-block, when we, with underwater, when we're going for an on-block resection, sometimes I'm doing underwater just because I wanna try to go for an on-block resection. So I think to not get a snare that's big enough. You've talked a lot about shapes. Do you feel like shape is mostly a matter of personal preference or something else? I think so. I think it's personal preference. I mean, I use the dug bill because the diameter of the dug bill is more in the transverse direction. And some of these lateral spreading tumors are more transversely in their largest diameter. But I strongly feel it's personal. I mean, there was a time when we didn't have these snares. I was able to take care of the polyps even with the oval or the round. So I don't know, what is your opinion or Tonya? My personal preference is largely, I like the Boston Captivator snares. I like, they come out and they have a little bit rounder shape than the classic oval and they're stiff. They come in 10, 15, 20, 25 and 33 millimeter sizes. I think, especially early in your experience, you wanna use 15 and 20. I tell people that a lot. I will admit a lot of times when I'm taking out something granular and it's got a great lift, I get a 25 millimeter. I took a polyp out yesterday that involved mostly the entire rectum, a granular homogeneous lesion. And I used a 25 millimeter snare because it's just more efficient to take big pieces out. But I think to be a little bit careful, but I do think you're right that it's a matter of personal preference. Tonya, you just joined us, you wanna comment? No, that was such a great lecture. Thank you for that. I think the snare agree. I think the stiffness is important for the flat lesions to grab that mucosa. And I also think like how you open it. I mean, the technique of like having the snare open and then coming over, or even using the technique where it's not the snare and tip, but because you haven't made an decision, but like having it. And then as you open it, coming back, you can sometimes change the shape of the snare according to your lesion. So I think some of it is also how you use the snare. So true, yeah, so true. You can use a 25 millimeter snare like a 15 millimeter snare. If you anchor the tip and then you open up and you push the sheath forward to close at the right position, you're absolutely right. I saw some questions that I think people are still kind of confused about electrocautery. I kind of wanna say that for snaring, we use higher voltage currents in general. So snare tip, soft coax. If you are using the snare tip, you generally always wanna switch over to soft coagulation current. Soft coagulation current is a lower voltage current. So you're gonna get less penetration. Soft coag is the main way that most of us control arterial bleeding during EMR. Because 90% of it is not from really big vessels. Sometimes you have to use the coag graspers. And then again, you're gonna use soft coag. Around the margin, we use soft coag because we're using the tip of the snare. So endocut is an alternating cut coag. We hit the yellow pedal for endocut. The first, it cycles first on cutting current. Tap the yellow pedal, you can go cut, cut, cut, cut, cut. And some people do that if they only wanna use cutting current. So my interpretation of the randomized trial, and so to my knowledge, it's the only randomized trial of current. And I used to be an endocut enthusiast. I used it all the time. And the fundamental belief was that if we use cutting current, we would have more immediate bleeding. And that's the kind of bleeding that we want because we can take care of it. Late bleeding by comparison is a disaster because, I mean, it's not a real disaster, but compared to immediate bleeding because the patient's gotta come back to the hospital. They may get admitted. They've gotta be scoped again. They may need transfusion. It's a much worse outcome than immediate bleeding. And so let's use cutting current and have immediate bleeds and avoid delayed bleedings. So this randomized trial that was done, it was done with, it was the Irby processor. And this, like some of the other new processors are what we call microprocessor controlled generators. They differ from some of the older generators and generators that are still out there, which are fixed output generators. You put them on 18 Watts and hit the blue pedal, you're gonna get 18 Watts. That's, the setting you put it at is the power that you get. On the Irby, you put it at effect to 25 Watts. And then if you look over, it'll actually tell you how much power it delivered. It might deliver four Watts or seven Watts. So it calculates the tissue resistance and delivers less power. So in this randomized controlled trial, what was seen was that there was no difference in delayed bleeding, but both of the currents were given what were delivered with a microprocessor controlled generator. There was more immediate bleeding with Endocut and there were numerically more perforations. My interpretation of that is Force Coag wins, but Amit, you're still using Endocut. So why do you like it better? I think Endocut, well, if you have muscle in the snare, Endocut will go through it when Force Coag won't, when the technician will sometimes tell you something's wrong, I'm getting too much resistance and you can stop and regroup. And I think Endocut will sometimes snap through muscle before there's an opportunity to do anything else. Not that that's the end of the world. You know, the Michael Burks of the world says, who cares about perforation? Just you take it when it occurs. But I don't know, Tanya, what do you use? And Amit, I mean, how do- So I'll just end mine and then Tanya. So I started Coag, then I moved to Endocut because you started talking about Endocut. And then I did fine with Endocut. Now you tell us that you're going back to Coag. So now I have to reconfigure as to what I want to do. So that's the short answer. Well, I hear you, but you know, when I first made the switch to Endocut, it was because of the logic that came out of old uncontrolled studies done with fixed output generators. Now, most of us are not using these fixed output generators. Now we've got a randomized controlled trial. It's more than 900 patients obligated to believe the results. And I will say, you know, I'll say, first of all, you know, because I read all Michael Burks. Michael Burk, as far as I'm concerned, is the world's greatest resectionist. And he's a very good friend and I read all of his stuff. But he has a lot more muscle injury than I have. You know, they report two to 3% muscle injuries. I don't see that higher rate. Maybe I'm a bit more conservative with my snare size and not lopping off great big pieces, but the perforations, the intraprocedural perforations that I've had over the last 10 years, I have all been with Endocut, really. And so, I don't know, I'm a little bit, I sort of think that just my anecdotal experience supports the results of the trial. Tanya. The question is, you had those, how would using Quag have prevented it? That's the question, because having muscle injury means that you have the muscular spropria in your snare. Now, Endocut will cut it faster. Force Quag might also be able to cut it, might take longer. Yeah, I just think that sometimes, and this is my guess, and I guess, I will admit I guess. Is that when, if you've got muscle in the snare and you hit the yellow pedal, that Endocut will just slam through it. Whereas Quag will get stuck. And the technician will tell you something is wrong. We can't, I've got this thing closed as tight as it is, and we're not coming through. I think that that happens and you stop and regroup, you know, and you figure out something different. Tanya, do you have a thought? Yeah, I mean, I definitely, my one thought is that I don't think that the group attending today should walk away thinking that you shouldn't use Endocut, because I think that it's still forced coagulation and Endocut in the study, I think showed okay. I don't think, I've always used Endocut. I haven't used Force Quag and I continue to use Endocut. I am someone who presses on the pedal, like steps on the pedal. So I think I'm even on the other side of more cut than any coag, because I don't have the pulse in between. So I tap, I tap, and I have a very tight snare closure from the beginning. So usually one tap and I'm through the specimen already anyway. I would say that I like it because I find it to be much cleaner. There's not as much white from the burn. So in looking at my resection margins, I really love that really like fine line as opposed to the whiter line. We then go and of course burn that. But for my initial evaluation, I really like that. I also like that when we're doing piecemeal with the sequential that you go, it just to me seems very cleaner. I don't have a lot of bleeding. I definitely have, thank goodness, very, in my time I've had one EMR perforation in an IBD patient. So I would say that I wouldn't just associate Endocut with perforations. Definitely I acknowledge the rates of perforation from Michael Burke's group seem high. And again, that may be more aggressive. Maybe they have many people beyond Michael Burke. You don't know, but I guess I'm just saying, I don't think we should all be using force coag other than I agree with what you're saying that force coag back in the day is very different than force coag today with the microprocessors. Yeah, so I think a point that you brought up, which is the thing that may really make a difference in limiting the thermal injury to the base is the speed of transaction. Right. The faster you come through, the less. And a point that you made, which is that if you squeeze the tissue that you have very tightly, kind of like almost as you were intending to do a cold resection because you've got a big piece of tissue, that that increases the current density in the snare. The current density increases with, I think it's the square of the diameter. So that gives you a very fast transaction even with force coagulation current. And having gone back to it, having used Endocut for many years, I think it's probably, I think the evidence, obviously we don't agree about this and that's the importance of this discussion is for people to hear different sides of it. But I think that force coag, the evidence from that trial, I think force coag won that trial. And there was a statistically significant difference in arterial bleeding. And we can all deal with arterial bleeding, but it's a nuisance if it happens. I find individual patients where, it seems like they have multiple arterial bleeds. I don't know why, but okay. Now there's some questions I think we want to clear up about, because we haven't talked a lot about injection fluids. So people are asking about, I was answering some questions, Amit, if you said a lot about injection fluid, but there's saline versus viscous fluids and there's contrast. So we've talked about the advantages of contrast. It delineates the margin. The second one is it stains the submucosa so that you can differentiate the submucosa from the muscle. I think in cold EMR, I have this feeling that it separates the submucosal fibers and it makes the transection a little bit better, a little bit easier. Just like using a thin wire does, because it's a little bit more of a knife-like effect. So I really like contrast if you're going to inject, but what are your guys' thoughts about this? I still know people that, I mean, experts that use saline. They still prefer saline, but there's some evidence that you take the polyp out in fewer pieces if you use a viscous fluid. Tanya, you mentioned that you like a dark color. I like a dark color too. I really like a lot of blue in that thing. But what are your thoughts about the fluid? And also people are asking, how do we guarantee with this dynamic injection, what is the fundamental maneuver of dynamic injection? Is it just lifting toward the center of the lumen as the injection is occurring? How do we optimize this whole thing? So regarding the type of fluid, I think the only advantage that I can think of in the literature that's been published about these viscous solutions is the efficiency, right? Number of pieces that you can remove is less and it's faster. Otherwise, saline, we use saline with methylene blue and indigo carmine for a while. I moved over to hydroxy ethyl starch with adding the dye. And then you come up with these situations where we were running short on methylene blue and indigo carmine. And these commercial products came up. So I can tell you, I mean, the reason I'm using one of the commercial products is because of the ease for the nurses and the techs. I mean, they all like this because they don't have to mix, open these vials and mix. But this is also a personal choice, I think. I mean, I think you also used to use heta starch, if I'm not mistaken. And you had this way of, which I started doing it in my places. If I had two or three EMRs, get a bag, mix it in the morning and then use it. And then pharmacy comes to know about it and they start creating a ruckus that, oh, this is like you're using the same thing for different patients. So it's more convenience, I think, that we've moved over to these commercial brands. That's my feeling. Yeah. I mean, we did at our center a randomized trial of, there aren't that many randomized trials comparing, but we did one comparing SIC-8000, which is Elavu to starch. And we found that by these criteria of the number of pieces and so on, that Elavu was actually superior starch. I still use starch some, especially with a really large resection where you're gonna have to use a ton of fluid because the fluid is expensive in these commercial products. And I do exactly like you said, I'll use starch sometimes when I have multiple EMRs, 10 or 12 scheduled in a day, because we are allowed to use one bag for, we draw it up in a separate room for multiple patients. I do prefer a viscous fluid. I think saline, too often it runs out, flattens out faster than I want it to. I thought O-Rise, which was off the market was too stiff. It just, it was like a rock. And I really liked when you were doing, for example, your cold resection, the way you were pushing the snare into your cushion and the pulp is coming up through the snare. I like to see that. And part of that is that the cushion is soft enough to allow the snare to go in. Tanya, what are we missing that are important tips about injection? You have talked for years about dynamic injection. What does it really mean? I think it just means your intention is to create more a bleb toward you rather than inject the fluid and it goes away from you. And so in order to accomplish that, you really need to, in your mind, imagine, I think one of you earlier said you had to imagine what the scope is doing. You said that, Doug, right? Like in here, you have to imagine where the needle is and you really want the needle at the, as close to that lavina propria as possible, like in the superficial submucosa. And in order to keep the needle there as you're injecting, you essentially like, and you don't, as you inject, you wanna look up or at the opposite wall depending on the direction you're trying to create this bleb. And as you're injecting, you don't want a lot of tension on the catheter. So the analogy I give is you want it like a putter with the golfing. You don't want tension so that can keep it right there. So because you are looking up and injecting, the lesion starts to come towards your scope. And so because of that, you need to pull your catheter back slightly as you're injecting, right? So the three maneuvers mainly are you have punctured, you're at the superficial submucosa, you start injecting. As you inject, you slightly pull your needle catheter back as you look up, and then you wanna suction the lumen because that gives more pliability, right? That allows you to stretch it more. If it's really stretched and tight, then your fluid's gonna go laterally or other places. You want it to be pliable so you can almost pull it towards you. So dynamic just really means that you're not sticking your needle in, injecting and letting the fluid find the space. You're creating the space where the fluid should go.

endoscopic mucosal resection

EMR

benign polyps

surgical dissection

invasive cancer

electronic chromoendoscopy

CO2

polyp resection

snare techniques

electrosurgical generators