So we are back now with Dr. Dennis Yan, and he's going to demonstrate ESD with the hybrid flex knife, which is a brand new knife from Mervy, available just for a few months. So Dennis, go ahead. Thanks, Dr. Dranov. So we're going to start with injection. We're going to inject the lesion, then I'm going to go a little bit more into specifics regarding the knife, because with regards to the strategy, it's going to be very similar to probably what you have already seen from the other endoscopists. So as you can see, there's our lesion. As probably the other doctors may have already explained, the first thing you want to do is examine the lesion. I like to run my scope around it to kind of identify any areas that are going to be more challenging. And with this lesion, for example, I can tell that as I move to the bottom portion, my scope is starting to loop. So that may be an area that I may want to take care of first. I also want to know where it's in relationship to gravity. So I'm going to start by injecting probably the bottom side, so I can open that side before we approach it from the top. Needle out? And I completely agree with this approach, because now when you inject that side, that will bring it closer to you. Exactly. So it will make it a little bit easier to access. So we're going to go ahead and inject. Oh, inject. Injecting, injecting. Okay, it's lifting there. Injecting, injecting, injecting. Okay, stop. Inject. Hold on. Injecting, injecting, injecting. One of the important things about injection is you want to do dynamic injection to try to shape the lift that you have. As you continue the injection, you kind of want to continue from the edge of that initial lift, so you don't have to try to find the semicosal space again. I think that's probably enough for us to get started. So as Dr. Drano was mentioning, we have the flex knife from Irvi. This is going to be a needle type of knife. This particular one is two millimeters in length, and it's in and out. So meaning the length is not adjustable, it's either in or out. The main difference with this knife as compared to some of the other knives that you may have already seen is the lifting capability comes with the water jet, so thereby it comes connected with a pedal, which allows you to inject under high pressure with the knife. And that's one of the main advantages of this knife. Knife out. For those of you that are familiar with traditional hybrid knife, a couple of important differences. One already was mentioned that it's predetermined length of the needle. The other one which is also important is that the shaft of the knife is thinner, so it compromises less your suctioning ability. It is I-type? I-type. This is the I-type. It comes in two configurations, I-type and T-type, and it's a matter of personal preference. I favor the I-type, but some people prefer the T-type because they can use that little plate at the tip to hook the tissue. So that whitish thing is muscularis mucosae. So again, because this knife comes with an extra pedal, I try to recommend people to use both of their feet when learning how to use this knife because it's going to be very difficult for you to alternate one foot between the yellow pedal, blue pedal, the Irby Jet, and the water pump. So I tend to assign my pedals, and I will tend to use my left foot for my electrocautery and my right foot to inject. And the advantage of that is then you can do both relatively simultaneously as you deem necessary. Hiro, what do you do about that? Do you use both of your feet? Yeah, so... So you use only one and you do all pedals? I prefer using my left foot, so I have both water jet and also the yellow and blue pedal on my left side, and then I keep my right foot as my kind of like axis. I put all the weight onto my right foot, and then I use my left foot. It's just a preference. It's a preference. Yeah, so that's why I'm still using the manual injection by the assistant. And to make my floor simple, like only foot pedal plus water jet. Simple, but it's simpler, it's still complex because you have blue pedal, yellow pedal, the toggle in between, and then the irrigation through the scope. The main point is whatever you choose, always do it exactly the same way. It has to become like driving a car. You don't want to be looking at your feet, which one is the gas, which one is the accelerator. So we're trying to open up this backside. As you can see, one of the key things about doing the mucosal incision is to open up that muscularis mucosa fibers to really separate the planes. Or else, what's going to happen is you're only going to separate the mucosa, but not deep enough, which is not going to really allow you to eventually get underneath the lesion. So you can see here, we're coming around the flap. In this case, we decided to go circumferentially, and then now you got to get underneath the flap. The idea is that you want to get as parallel as possible. Where's our specimen now? That's what happens. That one. Okay. So my strategy is gravity's coming this way. If I'm pushing my scope from this direction, I'm going to be more parallel. So from right to left, right? And we're going to suction a little bit. I'm starting to loop again. So what I'm going to do is just decompress, and that should be allowing me to get in a better plane right there. The other advantages from coming from the right to the left is that my mucosal flap is on my left side. And right now we're using an upper scope. So my knife is coming on my left side, which is going to be closer to my mucosa and further away from the muscle, as opposed to if you were to come from the other side. And that's an important point. Sometimes in rare situations, we will switch from upper endoscope to colonoscope for upper ESD in order to have that 5 o'clock position of the channel. Sometimes in the duodenum in particular, that may be necessary, even for EMR. Just opening up that flap on the top. So what Dennis is doing here, it's kind of a very good strategy. He's positioning the muscle on the right hand side, mycosis on the left hand side. And most of his movement is up and down with the big wheel. Which is the easiest movement with the endoscope. Big wheel up. As opposed to having to reach all the time for the smaller wheel. So Dennis, we discussed this already a few times, but do you close your ESDD packs? I think it depends. I don't routinely close all of my lesions. Gastric ESDD, I tend to close them. Rectum, I tend to close them. If a patient is coming in for a day case, they're on blood thinners, comorbidities, I tend to close them. But sometimes the reality is they're very challenging sometimes to close all of them. Esophagus in particular is very difficult to close. So the esophagus, fortunately, because it doesn't bleed as often, you tend to leave them open. Correct. And when you close, preferred method of closure? I like using clips. Just because now with the tissue opposition clips, it allows you to approximate large defects. And then finish it up through the scope clips. Suturing is probably the best closure device we have in terms of more secure closure. So for the stomach and rectum, where it's fairly accessible using maneuver, the suturing device is my favorite. So when you close the defect with the clip or suturing device, do you only take the mucosa and the submucosa, or do you sometimes get some superficial muscle? Yeah, that's a good question. If you were – so I don't think we truly understand if doing a mucosal – if the purpose of closure is to prevent delayed bleeding. We don't truly understand if just by doing a mucosal flap, it's going to reduce the risk of bleeding, or you actually have to get good purchase of the submucosa as well. So if it comes to your concern about defect, potential perforation, then it's not enough to bring out the mucosal flap because you're going to have a hollow space underneath it. So you can use the opposition clip to bring the flap together, but then you got to ensure that the subsequent clips are actually getting submucosa to submucosa. Okay. So preferably, I like to do submucosa to submucosa. If I don't have a perforation and it's only prevention delayed bleeding, I may have some areas where it's just mucosa to mucosa. You don't go full thickness? You don't go full thickness to the muscle? No, not even when suturing. I'll just grab it from the mucosal edge. Okay. Yes. So we don't have data. As a result, everybody does it different, but theoretically, you decrease delayed bleeding by two mechanisms. One is by covering it, kind of band-aiding it. The other one is by creating some pressure and compression for those blood vessels so they don't bleed. So if I have a really large defect, I would usually grab one edge, then grab in the middle some muscle, and then grab the other edge to avoid that pita or burrito or taco. The hollow space. Or calzone or whatever you want to call it, a type of hollow space underneath. Is it based on any data? Not really. It's just totally anecdotal. And we don't have the right answer, but we know that generally speaking, some type of closure decreases the rate of delayed bleeding. Yes. When using clips, what I found useful to avoid the burrito, or the easiest way to avoid the burritos, once you bring the flap through the middle to start the apposition, normally we bring the clip in the middle and we start from the middle out. Yes. But the middle tends to be the wider portion with the largest hollow space. So if you actually pin the clip on the edge, you're closer to semiclosa, so you can get a better purchase that way. So going from the outside back in as opposed to inside back out. So I get it. So this is very interesting because you combine two techniques. Normally with standard clips, we start from the end and work our way towards the center, the zipper technique. And here you're combining first you close the center, and then you start from the edge working towards the center. Very good. To prevent the hollow, because the edge is going to be more shallow as opposed to the middle where you brought it up together. That's a good point. Got it. Very good. So sometimes if you get the only edges, sometimes it makes big… Like a purse. Right. So I usually go kind of like a center part to approximate. Yes. And then that will make the clipping. Like a butterfly kind of… Yeah. For years. Easy. Those are great points. Yeah. Thank you very much. Very good. Let's see. No questions online. So we're in good shape. Thank you, Dr. Yang, for the beautiful demonstration. Thank you very much. Thank you.

endoscopic submucosal dissection

hybrid flex knife

dual-foot pedal control

ESD defect closure

delayed bleeding prevention