Hello, we are back and now we are with Dr. Yamamoto and he is going to demonstrate the tunneling technique which is another way of providing stability and traction without using any additional devices. And what currently Dr. Yamamoto is doing is he's placing marks for the lesion and as we have discussed in the past we prefer to use soft coagulating setting but in this case because this is explant we are not getting a great response. So there are a couple of things that you can do. Let's see. Yeah, that is doing it. If you're not getting a good marking, first of all make sure that your knife is clean. You may have to pull the knife and clean the electrode. That may help. In this case we are checking that the pad is in the right position and you can switch to forced coag if need be although that will be the last resort because you typically tend to puncture the mucosal with the forced coag and then the injection fluid starts leaking. As you can probably hear we are delivering fairly long pulses with the generator and this is longer than the usual. In humans typically it's much shorter delivery of this electrosurgical activation. So Dr. Yamamoto, tell us about what strategy we are going to be using for this lesion. Okay, today I am going to do the tunneling method for the esophageal ESD. So what I'm going to try to do is after marking I am going to make a distal injection and also proximal injection. Then I'm going to incise the distal mucosal membrane. Then after that I'm going to make the proximal incision and then make the submucosal tunneling. This is my strategy. Do you always inject both sides, the anal and the oral side at the same time or do you do one at a time? I usually do one at the same time for saving the time but if the lifting is not enough I do make the injection separately. Probably for our less advanced practitioners it's a good idea to inject only one side, create that incision and then inject the second side and create the incision. Because you don't want to feel rushed to do the two incisions. So now we are going to use the needle, injection needle, with saving. Okay, needle out. Thank you. Okay, injecting, injecting, injecting. Okay, thank you. Picoesophagus is very thin, extremely thin. Okay, injecting, injecting, injecting, injecting. Okay, thank you. Okay, injecting, injecting, injecting, injecting. Okay, thank you. So in esophagus do you usually always use the tunneling method or do you use the dental probe method? Thank you very much for the question. If the lesion is a small lesion, we usually make a C-shaped incision. But if the lesion is really big, especially for the circumferential needle, if the lesion required for the circumferential incision, tunneling method is a very good way. Then of course for the lesion, not needed for the circumferential resection, but still big lesion, we use a dental floss technique for the traction. Sorry, I make a distal. Sorry. What knife are you currently using? In our institute, we perform POEM in many cases, so we prefer to use TTJ knife, which is 4.5 millimeter needle, but we use a pro knife sometimes, but most of the case we use a TTJ knife for most of the technique. But in this case you're using the dual knife, correct? Yes, correct, yeah. But we can use many different knives. Oh, you can definitely use any type of needle knife. One warning about the TTJ knife, it is a great knife because you have so many cutting surfaces. Yes. And you can cut into any direction. At the same time, it's a dangerous knife and it requires excellent endoscope control. Yes. So probably not the best knife for beginners. Yes, I think so. But we usually use TTJ knife for the POEM techniques, so this is the knife that we usually used to use, so that's why we use a TTJ knife for the procedure, yeah, ESD or other procedures. You're using dry cut now, which is a pure, it's not a pure cut, it's a continuous waveform. Do you like the dry cut or? Yeah, I like, sorry, I should change to that. Oh, okay, so you usually use endo cut. Yeah, endo cut, sorry. I should change to the endo cut. Thank you very much for that. Oh, yeah, yeah, sure. I think you can probably toggle, let me, like a blackboard. Oh, great, thank you. Thank you very much for the correction. I like the endo cut better. Endo cut, okay. So after making the distal incision, I make the proximal incision for the, make the flap on the tonneau wing. Do you have any preference with the dual knife whether you inject with the needle out or the needle retracted or does it matter? It doesn't matter probably. I do not really care for this, I think. Yeah, I agree with you completely. Thank you very much. So this is probably the most dangerous part of the procedure now, the initial flap creation. Yes, I think so. So, need a special care? Yeah, extra care at this point. So in Toyosu, do the trainees need to do poem before ESC or like gas leak ESC? Is there any steps? We usually, yeah poems need an expert procedure as Dr. Dragunov said that. And also we use a TTJ for the procedure, so extra care is required. So we let a trainee for the ESC first. ESC first. Then, after certain experience, we let the trainee to do the poem procedure. So gas leak ESC or esophageal? Gas leak. Gas leak. Really easier one. And then poem and esophageal ESC? Yes. Okay. Thanks for clarifying that because I was surprised. Because esophageal ESC, in my opinion, is more difficult than poem. With poem, even if you cut the muscle, it's not a big deal. Yeah, that's true. With esophageal ESC, it's much easier to perforate and it becomes a significant complication. So you can appreciate guys how narrow the submucosal space is here. It's extremely narrow, but I think it's good to see how experts overcome this, not a fibrosis, but a very challenging situation. Exactly. I don't think it's going to go well. I'm somewhat concerned that I see muscle on both sides. I see longitudinal fibers on the top and it could be muscularis mucosa. Yeah, probably. I see. Is it too weak? Could you make it stronger? I'm sorry, Sensei. I can't get the balance right. We're establishing a good plane now. I want to point out to our audience that the porcine model in the stomach, the mucosa is much thicker than human, but in the esophagus it's much thinner than human. So it's not very realistic of what you actually encounter from that perspective. So this ESD is much more difficult than actual human ESD in porcine model. Obviously, as the name implies, ESD is endoscopic submucosal dissection, but in some cases we do dissect intentionally into the muscle for some more advanced cancers. So like intramuscular dissection, not necessarily in the esophagus that much, but in the rectum and in the stomach where the muscle is thicker, that can be done. That's one of the newer trends, certainly much more difficult than standard ESD, but it's doable. So I think, Toyosu, I think you do endoscopic subtherosal dissection, is that correct? Yeah, yeah, yeah, we perform ES, like full-layer, yes, we perform full-layer dissection too. So part of the reason we are not getting a great effect is that in the esophagus on the porcine muscle, the grounding path is not making good contact, and sometimes using cutting current may help. Yeah, ain't good. There we go. It's not working. I'll raise it a little more. Thank you. Tunnel. Yeah, that's a very important point. Thank you. So you always use spray coag for tunneling for the poem. Ah, yes. Thank you very much for the question. For ESD, you don't use spray, correct? Yes, most of the cases we use spray coag for the poem procedure, but not in the ESD. We use Swiss coags. But of course sometimes it's false coagulation for the ESD. But either coagulation, in either case it's acceptable, I think. It really depends. I think it's nearly end, I think. Okay. Yeah. Oh, nice. Nice. Thank you very much. Yeah. Nice. Now I know my end of the tunnel, because of the distal incision. See? Here you go. I'm going to try a different grounding. Here you go. I'm going to try a different grounding than I thought. Allow me just a second, I want to try to change the grounding pad. Oh, thank you very much. Because we're not getting a great effect. I will put it in the very proximal stomach, like right so. So let's try this and see. Can I make an injection for the needle? It seems like it's not lifting well. Can you give our audience some guidance when do you inject with the needle and when you inject through the knife? Thank you very much for the question. I usually use injection with a pro-knife, but whenever I think there is not enough lifting is acquired, I use a needle-knife injection. Thank you. I think we made that point a few times, but we like to inject outside of the marks. Yes, definitely outside of the mark. I try to inject where I want to cut. Exactly. That's the best way to describe it. Perfect. Inject where you want your incision to be. Thank you very much. Needle out? Can you needle out, please? Yep. Thank you. Any guidance, why did you choose to open the left-hand side first, rather than the right-hand side of the tunnel? Okay, thank you very much for the question. Usually, this is the gravity side, where the water usually sinks. So, if I leave it untreated, it's the place where I think it's getting difficult. So, I tried to cut this place initially. Well, I think for our audience, you've heard this message multiple times now. Always take the gravity-dependent side first, and keep the opposite of gravity side for last. If you do it in reverse order, it will be a big challenge. Do you occasionally use traction method combined with the tunneling? Yes, I usually use traction method for the esophageal ESD, because it's much easier and faster. So, tunneling plus traction. Yes, it's making the lesion, ESD faster. What do you do, clip and line usually? Yes, clip method is much easier, so I prefer. But, if the device is really big, from our institute, we published a paper called multi-traction device by Dr. Shimabara and Prof. Inoue. In that case, we use a snare and short clip, then we use a traction by the snare. It's called multi-traction device by Dr. Shimabara. Another benefit of using the snare is that you can pull, but you can also push. Yes, exactly. So, you can provide bi-directional traction. Yes, this is the point. Thank you very much. But, if the lesion is relatively small, clip traction is fine. The cheapest and the easiest. Yes, yes, yes. Correct. Okay, injection please. Okay, thank you. Okay, injecting, hold on. Okay, injecting, injecting. Okay, thank you. Okay, thank you very much. Thank you very much. I think we should grab by the forceps or do we have a raptor or forceps or oh I can't yeah we can push it oh yeah that's true do you feel okay yeah do you usually tape your cap ah yes definitely I tape a cap with an endoscope right here so um guys can you take a look it should be right there maybe that's cool yeah you can put the scope yeah oh then uh okay I see there we go okay that's true yeah you can oh oh that's again well it's coming up you know yeah it's they come out it's not did not come out Oh, cut or? Yeah, cut, yeah. I want to point out something very important how Dr. Yamamoto is cutting from the inside out rather than from the outside in which makes it safer. Yes, thank you very much for the comment. And he is mostly pushing the scope with slight tip up, very deliberate and controlled. Nice. Beautiful. This is extremely thin and fibrotic, so it's extremely difficult. I'm not good at tunneling. It's sweet here. So you can see how thin it is. You can see actually the outside, the muzzle. It's extremely thin. I never did ISD for the pig, so... So now on the screen, the 9 o'clock is the muscle. So Dr. Yamamoto is cutting from the muscle side and then bring it away from the muscle to prevent any injury to the muscle. Would you like a traction? Yes, I think I should use a traction here. Yeah, let me... Do you have a dental floss and a clip? Thank you. Yeah, so the question is, if there's any type of micro-perforation or something, how do you deal with? So, during the ESD, usually the perforation, so because you usually cut and look back, and then usually we can make the injury or perforation very small. So in that case, we usually extend the submucosal dissection plane a little more to make the space for the clipping. So we usually do use the clip to close the defect. And then, it's very rare, but if there's a very large perforation, sometimes we need a suturing device or putting a stent, but it rarely occurs. Then, I think compared to the EMR, because we have the direct view of the dissection plane, we have the control on those kind of adverse events. Thank you. Okay, so we decided to, oh, I think we need a string. Okay, good. Okay, a string? Okay. Shall we do a traction? Ah, yes, please. Okay. Okay, yeah. Let's make a traction. So, this is the clip and it's a dental floss traction, so it's already tied on the clip, so we usually do the clip insertion first, but this time we have the dental floss already, so I think we can advance this. Yeah I think we need to come and then we will pull the dental floss out of the scope. And then I pull, yeah, and then, yeah, let's push it. I think the floss is stuck on something, okay, okay, good, perfect, thank you very much. It's okay? I think so. Yeah. It's good. Is this okay to deploy? Yeah. Thank you. Then, so there's a tension on the dental floss, and then the Yamamoto is going to use the cap to go under this. Yeah. Perfect. Good. Okay. Thank you. So you can see how the traction is helpful. Open, please. Yep. So now, traction is pulling the specimen towards the oral side, and then Dr. Yamamoto is using the cap for the counter traction, basically pushing it against the target tissue. So, usually we have like Kelly cramp and then we usually hold this end, suture end with the Kelly cramp and then either keep it on the patient bed or use the gravity to apply the tension to the dental floss. So usually during the conventional ESD, at the end, the target tissue becomes very floppy. So in that case, the traction works. So whenever we feel the target tissue is very unstable or floppy, we always change our strategy and then we need to be very flexible to change our strategy always. So this case, we are planning for the tunneling, but this case is very fibrotic and then at the end, because we dissect most of the part of the submucosa already, it became very floppy so we decided to use the traction. So this is a very good learning point on how to change the strategy. So I'm putting a little bit of the traction. The only downside is we cannot, we don't have any control on the direction of the traction or only towards the oral side, but most of the case, this proximal side traction, so this is the best direction. So most of the time, we don't need a multi-direction traction, but in this case, as you can see here, it works very well. Yeah, almost, I think the other side is, yeah, just there. Right, only that area. So you can see the muscle is retracted, but Dr. Yamamoto is cutting just above the muscle, avoiding any injury to the muscle. Beautiful. Okay. Great. Thank you very much. Thank you, thank you very much. So you can see like almost half circumferential mucosal defect. That's a beautifully done. And we finally used the tunneling and then traction at the end. Dr. Yamamoto, thank you very much. Thank you very much. Thank you for kind attention.

esophageal endoscopic submucosal dissection

tunneling method

Dr. Yamamoto

TTJ knife

coagulation techniques

submucosal tunnel

flap creation

porcine models