Hi, everyone. Thank you for joining us today. Today's live endoscopy or live hands-on session is to demonstrate various technique technology again from the U.S. faculty mainly, and we have a pleasure to have Naohisa again as a commentator, and he's going to moderate the session as well. I have Theresa from ASG for assistant, and Carson from Korea Medical to assist one of the knives. So the demonstration is about the tunnel method today. I wanted to show how the tunnel method works and why it's beneficial, and today we have gastric, but we'll do the tunnel method in gastric. First, I want to demonstrate two different knives. One is a pro-knife for conventional mucosal incision. That is somewhat difficult with speed boat in the pig model. So I'm going to do marking with the pro-knife. I selected the position in the retroflex position. Traditionally, speed boat cannot do retroflex ESD because of the thickness of the device, but we have smaller caliber, which allows us to do retroflexion. I think it's going to work. First, I'm going to mark this area with the initial pro-knife. It's too soft. For demonstration purpose, I'm changing to force coag, but in human, we do soft coagulation marking. Pro-knife doesn't have to have opening of the knife. I think it's the power of force, because this is pig model. It's going to increase more? Oh, no, no, no. Oh, wow. That's going to be very visible. Yes, I think so. Just gently touch. Still not enough? I think it's still visible, though. Oh, no. I put so much this way. Oh, let's see. Let's continue marking on a straight position. That's good. That's good. Thank you, Naohisa. My pleasure. I'm trying to do a little bigger marking. I hope I can get there. So, this is a marking. I'm going to retroflex. Oh, my lord. I can't do retroflex. So, I may have to do straight. That might be difficult. I brought myself trouble. Let's see. Retroflex from here. There you go. So, I have to just retroflex from this way, and that will work? Thank you. So, let's show a different coagulation mode. So, Speedboat has a radiofrequency cut, as well as microwave coagulation. This is a bipolar device, so you don't have to do grounding. And, let's see, in between, there's a mouth coagulation. It takes several seconds, and usually gives a really nice blanching effect. Do you usually use microwave for the marking? Yes, absolutely. So, this is just a marking, blanching. It doesn't have any cutting property. In this model, it's not too visible, but that's how it works. By the way, this electrode is relatively big. How large are the working channels necessary for this device? Thank you, that's a good question. It used to require 10 French channels, the therapeutic channel. This model, this new knife, has a 3.2mm compatibility. So, you can use a 3.2mm channel, which is a therapeutic upper, or pediatric colonoscope in Olympus model. But, for Pentax, and some of the, I think Fuji has a larger channel for regular upper endoscope. And, what we need to do is just a little torquing direction. So, let's tilt left up. It's like this, there's a little bit of white at the edge, and there's a full length comes up. And, the full length area is active electrode, all the way to the tip. So, it's about 4mm length. So, we typically control the length of cutting by pushing out or pushing back. Difficult location, we pull back. It's an easy location, you can see everything. A little more distal, I mean, extend more. And, left up. The electricity goes from the top of the gold plate, down to the left side of the whitish. And, bottom has a little bulge, it's called hull. So, that kind of pushes unneeded area to be cut, push away, so that the cutting area is concentrated at the tip on the top side. And, right up. And, the electricity goes from top to bottom. And, you see the gold and the white? This is really cutting leading edge. That is a really sharp area to cut through. So, we'll demonstrate that in a minute. So, let's see. First, injection. We're going to do tunneling method. That means we have to... Let's put your flexible arm first. So, with this view, the end point is an area that you have to open really wide. So, away from your entry site, you incise first. Now, how would you approach this area? Would you do straight view? I usually prefer to start the incision with the retroflex position and starting initial injection and mucosal incision at the oral side first. Oral side, in the same way. That's great. Kneel out. Okay, let's inject. We'll give a little nice lifting stop. I'm sure everybody saw it already, but I'm doing a dynamic injection. Injection 2. By the way, what kind of solution are you using for injection? Currently, what we have is... EndoBoost? It's from Microtech. Sodium Hyaluronate solution. Yeah, it looks like a little thick, but not too thick. Hyaluronic acid was used initially for ESC in Japan. Yeah, that's right. We'll see how it performs. Inject. Stop. Because of the viscous nature of this solution, it stays a little bit longer than any other solution. Yep. Inject 1. Stop. I typically try to control how much injection comes up. I mean, lifting occurs. I avoid over-injection. I don't need to just keep injecting. It's quite important to recognize a nice lifting sign when we conduct submucosal injection. I totally agree. Injection 0.5. Stop. If it doesn't lift up well even after a few milliliters of injection, the knife tip already penetrated through the muscle layer. That's a dangerous sign. Therefore, we should recognize a nice lifting sign. Absolutely. So this is a really nice bulge that indicates that it went to the submucosal space. Do you want to try SpeedBoat maybe? Let's see if the SpeedBoat cut works. I'm going to continue on this one. If not, I'm going to open up the mucosa first and continue with the SpeedBoat. Depending on the endoscope, as you can see, this has a 3.8 millimeter channel. Probably the device comes from the lower side. Yep. Lift up. That means if you go from left to right, you can see the target much easier. What we're going to do is pull back and indent. Since my direction is going to be this way, I'm going to make a right up a little bit. Remember, I emphasized the gold plate to the white. That edge is the cutting leading edge. First, make sure that I'm at the edge. Right up. A little bit of indentation and then cut. Oh, not this one. As expected, it's not cutting as much. Let's see. Lift up. Typically, the hull area is pointed towards the area you don't want to injure. The bottom side is the tumor or target area. The hull should be at the bottom. As expected. For some reason, the dead tissue in the pig's stomach just doesn't open so quickly. Probably due to the thick pig mucosa. For the human procedure, it becomes a little bit easier. Yeah, it's much easier. Open. It's a 2mm, so we can just give a little indentation. Incision mode. Hold on. Incision mode. I performed endocut first. There you go. The tip went in. From here, I'm going to ensure that the needle goes in adequately. It didn't move, so I'm going to start moving in that direction. At this point, I should probably pull back the knife to use the cap as guidance. Always confirm the depth first. I think I see the blue. But I want to inject a little more because it seemed to be injection is not adequate. So this ProKnife has a capability to inject. I wonder why it just didn't stay elevated. Okay, prime it. Inject, inject. Inject, stop. All right, so it comes right in the center of the knife. Inject now, one. Stop. So now I'm gonna hook the tissue with the knife. And this tension is always important. How much tension you apply. This tension is not gonna cut because you're just barely touching the cutting area. So you have to get the tissue contact adequately. If you pull back too much, this is too much tension. Yeah, that's a very important point. So now, so is this adequate? I think so, a little bit less, but. Yeah, a little bit less, I agree. So just get a little more onto it, it's perfect, right? Yeah. And every cut, I'm gonna be adjusting to the different direction. Inject one more time. It is very important to control the endoscope step by step. If you try to control rapidly, it doesn't cut well. Exactly. So slower is sometimes faster. Yeah, that's right. I'm gonna just say incise the mycota again. It didn't go in, so it's not adequate yet. Not yet. Yeah, I think it's penetrated. Let's inject a little bit. Stop. So leakage, that means I didn't penetrate it enough. There you go. Oh, no, it's gonna come in. Inject a little bit. See, everything is lifting up, so I'm in the semicosal space. I cut three times. Four times is probably the nice, nice rhythm. Do you agree? Yeah. If you're fast like you, and you can control, you can go all the way. But we should check the direction of incision, so I sometimes stop and check the direction and control the angle or control the distance. Agreed. So these are the markings, and I was going to the right direction, but if you keep cutting, you may lose the direction, right? Yeah. When you pass the tool, you have to go away from the target area. You don't wanna poke. And right up. I'm not rotating. Carson is rotating for me. Right up a little more. So I'm gonna use the right shoulder for cutting. I'm going to the semicosal space. Remember this white to gold transition is the starting of a four millimeter. Oh yeah. It's two pedals, so they're confusing. I'm gonna give a little tension, right up. Oh, it cuts very well. It cuts really nicely, right? And I want to make sure that I'm not cutting too deep, so I pull back a little bit. Yeah, because you mentioned that the cutting area is until the top of this electrodes, so if you insert too much, it is dangerous situation. Absolutely. So everything inside a cut area, so you have to control the depth. I'm seeing the end point is there. So in that sense, using ST food is the best combination because we can keep the safety with the long transparent food. Absolutely. So that would control the depth on the knife as well. And we found that this is the best match with the tapered cap for this speed boat for now. So I want to go to three o'clock, 2.33. So Carson did the right thing. Just a little twisting. And I'm gonna keep cutting the same way, the top, I pull it up. Go back in again. Make sure that you're not cutting too deep. This is a good direction, shoulders at the direction. So a little more left up. I think you need a little more sharp edge. If he doesn't move, you're gonna give a little more tension. For some reason, it has the left right up a little bit. I noticed that the lifting is not adequate. So I immediately start pulling back, making sure that I'm not cutting deeper. So here, the right side is white. I get really nervous. Yeah, this whitish area is already must rare. Right, so from that, I have to go from right to left. So I'm gonna go from right to left. So I'm gonna go from right to left. Left. And a little tension. It's too much, so left up a little bit. Right up. So this coordination takes a little longer to get used to. But once you get used to it, we have a really nice theme. Left up, we're gonna finish there. So there you go. Oh, nice. So the depth is good. Incisions good. So now we're gonna start doing the tunnel. Do you like this tissue effect? Yeah, the burning effect is minimal and the cutting edge is very clear. Yeah, and it has some coagulation property when you're cutting. So all the smaller, oh, sorry, injection needle. Smaller vessel could be taken care of at the same time. So basically, you are using a bipolar mode for mucosal incision. That's why some of the damage is minimal. That's right. And it uses very low voltage. Yeah. And it's consistent delivery of the wattage at the area. So it's a very thin area that they have to conquer. Needle out. Inject. One. Faster. Stop. Inject. Stop. One more. Inject. Stop. Needle back. So that's the, I typically take a little larger area of the distal end where you're gonna enter the semicordial space. That facilitate, let's do pronate for opening. That facilitate entering to the semicordia much easier. I changed this practice a while ago. Do you agree with this approach? I am. Would you cut at the foot of mountain or middle or top? Middle. Middle. Okay, good. Open. I agree. So I'm gonna probably cut this area. Oh man. This positioning is a little crunky. Hopefully once we're in the semicordia, everything is stabilized. Mm-hmm. So this is close to the foot of mountain. And cut. Don't you think a mucosal incision is one of the most dangerous part? Yeah. Mm-hmm. Okay, now it's a one in. As far as we can create a nice submucosal breath, it is relatively safe. That's a good point. And always make sure that we're getting into the right place. So after several incision, it's always a good idea to just confirm. Are you doing it? Okay, let's inject and see how. Inject. Inject. Up. Okay. Do you like this interval? It's very slow to me. I usually step the foot pedal intermittently, even if I'm using end cut, then we can control everything. Perfect. So you go by stepping the foot pedal and control everything, yes, by ourselves. Oh, it's already muscular area, so be careful. Yeah, I think this is the area that I didn't get injection too much. Okay, inject again. Up. So the problem is every time I try to go retroflex, it slipped over, so I'm almost like a 45 degree. Mm-hmm. So in this case, the muscle direction is really close, and the injection is here. Probably it's really at the foot of mountain. That was the problem. So I'm gonna go a little up angle to just, and change the depth of cutting. Still, it's kind of exposing muscle. All right, let's do a proper injection. It's kind of tracing the surface, but not cutting too much. So that's good. Let me reposition again. Needle back. Sorry. So that illustrates how important it is to reconfirm where you're cutting, and how much is the injection solution is. Needle out. Inject. Good, stop. Making me feel better. Inject. Good, stop. All right, needle back. Is it okay now, Hisao? Yeah, yeah, of course. Thank you. Okay. Let's continue with the speed boat. One thing I didn't explain is that there's a needle with an injection capability. Needle open. Like this. Needle out. It extends about five millimeter. Oh, five, that's very long. We told them that this is too long. Come back. So this is a really good addition when you do additional injection during the semicircular dissection. And then we'll go out of the field. Wow, this endoscope here is so long. Is it coming out? Eventually. Okay, right up. See, the passage of the device is so smooth. Even with the retroflection, it comes out. Because of the 3.8mm working channel. Yeah, so that's a really good improvement. Let me go back to Antrim. Okay, it's really funky. That's good. So I'm going to go to the right side to open up more. If I push too much, then I'm going to lose my position. Okay. There's a different push switch. Carson, you're just holding down. Thank you. Alright, so I'm just going to get the edge. It's always important to get the whole mucosal. Right up. And once you're in, I'm going to be really careful. Not to go too deep. It cuts very well. It does, doesn't it? So would you have advice on how much you're going to open this area? I usually open around 1cm long. That's usually good enough. I think the opening of this ST food is about 7mm. So make it a little bit larger than this. I agree. The opening should be limited to get into the semicosal much more effectively. So what I'm doing is just attach the tissue. Give a little directional approach. Sorry, that was my spastic left foot. Left up. Right up. Let's go left. So one of the features of the hull, if you push it away, the muscle gets pushed down. So it's less concerning to the muscle injury. Nevertheless, you can, so you have to be very careful. The semicosal is probably open now. So utilizing the upper limb of this transparent food, Norio easily goes into the semicosal space. Yep. And it's important to catch the edge of the tissue, the mucosa, to push it away. Otherwise, you cannot get in. I'm gently opening up. Now he changed the direction of the target tissue by opening the semicosal space with the transparent food. That's right. That's why transparent food is very usable. I pulled back the knife because I was getting a little perpendicular. Right up. I'm going to cut to the left. So get the shoulder to the left. Getting close to the muscle. So we should check the blue color of the semicosal layer. If it becomes a loose blue color, it becomes a little bit dangerous. But if we recognize the dark blue color, it is a safe sign. Now we can see the nice blue colored area here. Yep. So always look at what's in front of you. I try not to touch the knife as much as possible, but this is a little clunky. So hopefully that will give me a little more freedom. So even in the semicosal, you see if there's any blood vessels or not. If there's a blood vessel, you can do proactive coagulation. This is a microwave coagulation. And the bubble is good. It went to 100 degrees. So denaturing of the protein starts. And then once you finish the coagulation, you have to cut the desiccated tissue. Otherwise, it will shut the semicosal layer. So close up. I'm trying to understand if pushing works. Okay, let's try the injection. Flip. Show me the needle. Inject. I mean, needle out. Yeah, that's okay. Okay. So I'm going to control the needle tip and inject. Stop. And then to the right, inject. Go for it. Go for it. Inject. More. Perfect. Needle back. And we have to make sure the needle is back, so I pull back. And I'm going to go from left to right. That's the safest way. So I'm pushing in. I limited my needle tip to probably at most two and a half. You can limit a little more or less, but because the approach is a little more difficult, I'm going to keep doing this for now. And go to the left. You see the left side also activated. That's all active area. But if you touch the tissue more to the right, the right side gets cut. That's a very interesting phenomenon. Left up. That's not a good approach. Good. Cut. Tension. Cut. This is an important part. You want to cut here. You cannot cut here like that. You have to give a little more indentation. It is a little slow, so I'm going to do a little more. A little more. A little more. So it's a repetition of this adjustment. And you saw Professor Yahagi's demonstration yesterday. He's doing it so much quicker, and it looks faster and safer, but the principle is the same. Right up. Left up. Embed the tissue. I mean, tip of the knife into the tissue. Cut. By the way, is this bipolar cutting mode? That's correct. So even for the submucosa dissection, you use the cutting mode. Exactly. Instead of finding blood vessel, you will use microwave. Coagulation. That's right. This cut is almost like a blend of the dry cut with the coagulation. It cuts nicely, but some coagulation effect exists. Right up. But there is no... Charring, right? Yeah, charring. Just make sure that I'm cutting right plane. Cut into the tissue. Grab the tissue. So this one, I think it's a little more left up is ideal. Good. If the cutting doesn't occur, you always try to adjust the angle. One thing is still we're trying to figure out is under the water, this bipolar doesn't work as well as in the dry condition. Oh, really? Yeah. Usually bipolar works very well even under water condition. I sometimes use bipolar hemostatic forceps. It works very well even under water condition. Yeah. So it could be just a setting of this chroma. Probably due to the large electrode of this device. That's a possibility. So we're trying to go forward. And usually the air in the semicircular space is a sign that it's close to the end of it. Is that the end of it? Maybe not. Maybe yes. What would you do if you're lost in the semicircular space? I just pull back the endoscope and check the dissection area from the luminal side. That's very simple and the easiest way to check. Proper way. I'm going this way and the tunnel goes straight. So I'm in the right place. Yes. We're almost done tunneling. Since there's still blue, I'm going to keep marching forward. Right up? I mean left up. Sorry. Good. I frequently make a mistake saying right and left mixed up. But my tech is usually really good. Yeah. That's what I meant. Okay. Let's do an injection here. Yeah. Usually you flip it, but I typically just withdraw so that you can see the needle exit. Inject. Good. Stop. Inject. Stop. Now I want to ask you a question. Oh, that's the end of the tunnel. This is almost the end point. So over-injection is a frequent issue. I know that in the past I always said there's no over-injection. But actually it kind of sets you back because it expands. What is your advice to the audience? In case of injecting too much solution, I think combination together with the water pressure method is the best solution to solve that problem. Even after over-injection, still we can do everything within underwater condition. That makes sense. I think injection solution is the key. If it's a fluid that exits quickly, then over-injection can be corrected. But long-lasting solution. Lift up, Carson. Lift up more. Good. See the shoulder to the end. Long-lasting solution. Once injected, it doesn't leave. And sometimes it goes to peripheral part of the target tissue. That is the problem. That's right. I thought it was going to be over, but it's still more. As far as we are using grease solution or normal saline, there will be no problem. So I changed... Stop. Inject again. Stop. I changed to the foot pump injecting saline so that it just exits when over-injected. Do you use glycerol? Yes. Usually, yes. But glycerol also disappears a little bit earlier. Oh, nice. Any questions from audience? Could you read the... Oh. There's no question from the audience. All right. Let's march on. Because it went very smoothly. There's no bleeding. Lift up. Capture the tissue. Give adequate tension. Not too much. If it starts moving too fast, then you have to readjust the tension. Am I overshooting? Oh, I don't think so. Oh, cap came off. That's sad. Can I have a rat tooth? It seems to be at the right direction. Yeah, almost there. Or biopsy forceps or grasping forceps. I'll try to find grasping forceps. Any questions from audience? Do you have grasping forceps here? I guess not. Do you have grasping forceps? So I'm going straight to this direction. Injection is done. Most important part is just incise adequately to close the muscle layer. Once the proximal end is not obscured, you overshoot frequently. So Carson, why don't we do a little more incision here? You see a lot of semicircular tissue you can see? So I'm afraid I may have overshooted. And to mitigate that issue, I always try to get close to the muscle layer. Oh, sorry. You shouldn't be doing that. So when you pass a device, always just push it to the straight, the non-target area. Okay. So this time I'm going to again do the cut current. And this area you need to go a little more right up. Perfect. I hope I didn't overshoot. I'm not using a cap because I'm almost parallel. And you have to just use your sense. It's always good to have the cap back on. Open. Close. Open. Close. Does it come with it? Just leave it there. Open. It came out. Close. And you really need to get the cap. Oops. The cap was with it. Where is the cap? Did you see a cap? I don't see a cap. So it must be inside still. No, no. It's already outside. Yeah. Strange. Open. Close half. Okay. Close now. Good. I knew that I didn't see the cap. When you're extracting from the body, always keep the view on the foreign body because you don't want to lose it anywhere. Yeah, to avoid injury or losing the target. And especially if you lose it in the airway, it's a disaster. Okay, out. Thank you. Open. Okay. To get it back with it, you clean up. You will dip with the water. Can I have the tape again? If you have one. Over there. The tape is located over there. Is that the common tape that we use for endoscopy? Let's make sure that it goes 360, okay. View is clean, that's one benefit. This is the entry site. I'm gonna go into the antrum and then retroflex. Here's the entry site. For some reason I have to push from here. It's very interesting anatomy. So it should be mostly there. Now, Hisao, do I have to inject again? Oh no, I don't think so. Because of the lesser amount of tissue, probably injected solution doesn't stay anymore. Yep, that's a good point. Right up. So make sure that the muscle is on the hull, the backside. And I withdrew knife a little bit, so I extend it a little more, and trace the muscle. Oops, I knew it. So that's a bad cut that you are not controlling the direction. That's a good example that the tip of the knife can also cut. It's a really nice clean cut. It cuts some mucosa, but if you're onto the muscle, it will cut the muscle for you. Let's see. Am I shifting to the right? No, actually we're on the right target. Let's take off a little bit more. Right up. Lift up, lift up. It must be end of it. So this is a tip cut. If you have a very narrow area, you can use a tip only. This is really beneficial for area of the fibrosis. Oh, it looks a little bit strange. There's no blue color. Please check the incision line once more again from the luminal side. Did I go to the left side? Because still there is a blue color remaining on the opposite side, therefore it is a little bit strange. Maybe I shifted to the left. That's a good point. Thank you. Right up. I wish everybody has a Naohisa AI machine. No, no. Please check the direction. This is too much. Right up. If it doesn't cut so much, then the edge is not there. So if you adjust it, it's going to cut right away. Okay, needle out. Good. Inject. Stop. Where is the end of it? Inject. Stop. Inject one. Stop. Needle back. It should be able to be there already. So maybe when I'm pushing, probably you should go to a little bit right side from the tunnel. Andy, are you heading home? Thank you so much. Thank you. Thank you, Andy. So as I said, we're going to be doing a little more proximal incision. Now with the cap, so we can get a little deeper. Is it possible that I didn't cut deep enough? I think this is deep enough, because submucosa space wide reopens now. It is, right? I push it out so that I have to hook it to the mucosa side so that I can cut safely. Oh, that was my bad spastic foot. Let's check. Oh, still strange. All right, let's march on. When I'm pushing it, I feel that I'm going to the strange direction, so straight. Okay. Straight. Should be this way. Yes, keep this direction. Yes. To mitigate this issue, we usually incise the proximal end or end point much wider and deeper. Yeah. Again, I'm confirming what I'm cutting. Adequate tension direction. Oh, there you go. Definitely overshoot it. Way too much. Well, well, well, well. The learning point is make sure that your path is correct. Underneath the tunnel, it's very difficult to see which direction you're going to go in. Yeah, yeah. Now we have the, you see the bubble? Yeah. We saw the bubble and I was explaining bubble is the signs of being the end of it. You can see the end of the mucosa incision here. You see it? Yeah. So we can open up to that side and cut there, right up. Cut right up. Good. Okay, very good. So it's open wide. Oh, so the problem is now I really want to leave the semicosa to the edges. That can be a little challenge. All right, Teresa, let's do injection. After this tunnel creation, you see, if you put the air, how easy is it to access semicosa? So that's the beauty of the tunnel method. And then I'm going to work on the right side because I need out. Inject. Stop. Inject. Stop. That's good enough. Inject. Inject. Perfect. Stop. Nice. Let's go to the left side because this is a long lasting solution. Inject. Stop. Oh, it's still there. Nice. Inject. Inject. Stop. Need it back. I want to demonstrate how leaving semicosa is beneficial. So now, Hisa, what would you recommend for the next step from here, usually? For me, I would like to complete the circumferential mucosal incision. So we agree on it. Good. Left up. I use a little bit of reach, like a paper cutting right up. I wedge into the tissue. Right up. Good. Left up a little bit. Good. Good. So I want to leave semicosa. That's perfect. Then keep going to the proximal end. It was accident. Right up. Good. In human cases, it doesn't smoke this much. Right up. Good. Control it. Control it. A little more control. There's no need to rush. Make sure that the negative margins are preserved. Okay. You can keep going like that. So it's frequently coming back because I'm not catching too much tissue. So I'm going to push it out a little bit. That makes it much easier to control. I'm controlling direction. It was an easy movement. Right up. Actually, you want to protect the mucosa, I mean, lesion, so it's going to be left up. Perfect. Now I wedge into the tissue. That was a spastic foot. Right up. Almost. Right up. Okay. Very good. Let me close this card. Mm-hmm. This left side, so it's going to go this way, I trace back up, left up, left up. It's much more easier to see the direction, so I do left up here, you can go straight, left up. I thought that was a marking, but it was not. Again, I need to cut, capture tissue a little more. By the way, for biosystem, there are several cutting mode. For this machine, do you have any other cutting mode? That's a great question. So, because of the bipolar control, there's no need to change the setting at all. I use this for mucosal incision, submucosal dissection, muscle incision, pretty much everything is the same setting. So, a little bit of tension, cut, and kind of directing to the end point, and then complete. So, what we're going to do from here is, from inside, let's put a little more air, so that they tense up. If you take care of the left, left is simply more difficult, right up. Sweeping motion from inside out, left up. So, I'm using the same, right up, right up. Good. Using the same cut current, going to semicosal space. This is what the bridge all left. So, you capture here, you don't need to be greedy. All the way, right? If you don't go all the way, you're going to be in big trouble, left up. So this is not cutting well, right? So right up, perfect. That's opened up the semicircular space. It's access for you with attention. And this one, from inside, if you take care of this area, it start opening up in front of you. So you have to make sure that you don't have a vessel. If you have a vessel, pre-coagulate. Using microwave. Microwave. Let me show you the example. Microwave, coagulate, coagulate. It shrinks down the vessel. Without 10 seconds. 10 seconds, it's a lot. It's auto-stop. So that should be adequate. If it's a big vessel, you can do it one more time. Oh, really? I usually do a test cut. And if it's touching the blood, coagulate again. But then, no blood, cut through, lift up. So in case of finding a sick blood vessel, or some bleeding, you don't have to control anything. Just touch to the target tissue, and press the foot pedal until it automatically stops. That's right, that's a really key point. If you see bleeding, you don't want to move. You just apply coagulation. And if you do that, most of the bleeding can be controlled pretty quickly. If you come out, and then use the position, then you have to readjust. In the meantime, blood accumulates, and you're in big trouble. Yeah, yeah, sure. Okay, here. So it is quite a big benefit that you don't have to exchange device during the procedure. See, this is a tonal method. You see the tonal and submucosa left? All you need is just take care of the submucosa right and left, left up? I mean, right up, sorry. Now, everything looks very smoothly, but I think that it is necessary to have certain experience to control the device properly. How many cases would be necessary to become a competent rebel? Yeah, the perfect question. Yeah, the perfect question. So even with the expert, if I give this knife to Dr. Yahagi, probably it's gonna take at least two, three. It took nine for me, left up, to understand the feature of the electric, the energy delivery, and how coagulation works. So there's always learning curve, but it can be really safe. Because you have all the coagulation and cutting mode in one. So I'm gonna cut the right this time, left up, left up. And then right up, right up, I mean, left up, sorry. See, I'm getting confused myself. This is a really accessible, you can see thing. So I'm gonna extend to four, that will speed things up. Four millimeter, right up. And one more time. And see, I don't wanna cut everything, but I can do probably one more time. And one more. The tunnel method, you need to just leave a little bit semicircular tissue on both sides until the end. To keep enough tension to the tissue. This is a tension method, so then this side, right up. It's an important part, it's, let's say, left up. Example, it's a perpendicular approach, doesn't cut that well. So you go right up, keep the edge, and cut through. So that's the part that many people get a little bit, require a little bit learning, but keeping an edge is the most important part. So this one is almost to the end. And this is almost at the end. So let me ask Naohisa, which one would you take out first? I will cut the left side first, because the right side is on the upper side according to the gravity, it's hanging down. That's the most important part, just taking off the right part first. If you cut the right side first, as everything is onto the wall, it's gonna be very difficult to expose the cutting area. On the other hand, as Naohisa said, right side is at top of the gravity, so it's gonna kind of hang out. It's really easy to identify the cutting plane. So according to Naohisa's advice, I'm gonna go left, little by little. I guess this is it. Oh, one more. One more. Ah, you're right, Naohisa. Then left up, remember, and there's no blood vessel, so I'm gonna be extending my knife to utilize all the four knife length, and that's gonna be probably one sweep. That's it. Oh, great, congratulations. Thank you so much. I'm sorry that I overshoot it. A lot of overshooting. Yeah, so we should be careful looking at the color and the space of the submacular layer. That's a really good point. Once you start losing the injection, you have to wonder why there's no injection fluid. I should have thought about it. And then I was pushing it, and for some reason, I was shifting to the left. And then the third point is incision to the submucosa down to the muscle was a little inadequate, so we lost track and went to end. So that is the essence of the tunnel method. If you have any question, I'm happy to answer the question. Naohisa, when would you use this technique and why? When the region size is relatively big and located at the gravity side, I prefer to use this technique, and also relatively large region located at the esophagus. You can create a long tunnel. Yeah, yeah, yeah. And because of the straight lumen, creating tunnel is relatively easy in the esophagus. Good point. I typically don't use the tunnel method in the stomach because stomach is much easier. The submucosa expands so nicely. But for colonic ESD, I found it's really useful. I use it exclusively for almost all colonic lesions. Oh, really? Yeah. But in case of having lesion located at the undulated area, such as splenic flexor or hepatic flexor, is it possible to do this technique? Absolutely. Oh, really? So once you're in the submucosa layer, it gets really stable. The next thing you have to really focus is to identify the separation between the muscle and the submucosa. Because as you pointed out, flexure tends to be a curvature. When you're going forward, your muscle, you're going to curvature. Good. You're going alongside and you start getting close to the muscle. So you have to redirect alongside. So this sudden appearance of muscle, it's a risk for perforation. So you have to keep watching this muscle layer and naturally curve around. If you can do that, the tunnel method is a really nice way to stabilize the endoscope and create the tension, mitigate the need for additional traction method. But of course, traction method is always welcome. It's needed. Like internal traction. I think for the smaller lesion traction technique, it's much easier. But for the bigger lesion, I think tunneling method is much better. Good point. For when you use a traction method, would you do full circumference incision first? Yes. Yeah. It gets a little more difficult to access the mucosal incision. So you have to strategically cut all the way around 360, like a conventional gastric ESD, create a pocket or maybe create a pocket and just do the incision like we did and then attach the traction so that you can get the really easy access to submucosa. Do you agree? Yes. Of course. Great. All right. Thank you very much. Thank you.

endoscopy

gastric lesion

tunnel method

pro-knife

force-coag

retroflexion

speedboat

submucosal injection

coagulation

colonic lesions