And these two slides show my setting of electro-surgical unit for gas leak ESD. It's a little bit complicated and it's different mainly for the IT knife higher setting, but we usually use this dual knife type. And the setting for dual knife is mainly for swift coagulation effect 3.5. And the detailed setting is here. You can see later in the handout, so please check it out. And I think one of the most important point for success of gas leak ESD is predict the technical difficulty of gas leak ESD. The technical difficulty differ according to the region location in stomach. This shape is the stomach, but during the procedure, the patient lay left side down, so the gravity force go this side. And the blood vessels are lot in the upper stomach, and the wall thickness is thinner in upper stomach. So the region location strongly affect the technical difficulty of this procedure. For example, the greater curvature in the anterior or posterior wall of the antrum is the easiest location. And the lesser curvature of the body, we can use gravity well, so it is relatively easy. But in the lesser curvature of the gas leak antrum is relatively difficult because we can't use gravity force and the region easily sink in the water. And the gas leak body and the pilarus and the cardiac is the difficult part of the ESD. Actually, the gas leak fundus is most difficult part. It is quite thin wall and the approach is perpendicular, so easily make a perforation. So this kind of region should be performed by the expert. Also, region size and the SM invasion and the obvious fold convergence is the characters for the technical difficulty. Large region size, more than 40 mm, and possible submucosa invasion and obvious fold convergence often cause the severe submucosa fibrosis and make a perforation and bleeding. And one point for the gas leak ESD is lateral flex position. This is mainly for the regions on the gas leak body and you can keep tangential approach and you can reduce the respiratory movement. So please try to make a lateral flex position, you perform gas leak ESD. But the lateral flex position is a little bit complicated and for the cutting in the lateral flex position, then cut is from start from the distal side of the region. And in the straight position, then mucosa incision should be start from the proximal side. And the manipulation of the endoscope is completely different in the lateral flex and the straight position. So you should get used to be the lateral flex position, especially to manipulate horizontal direction, lateral flex position, you just twist the shaft of the endoscope. But in straight position, you can use the right-left angle also twist. And the distance adjustment is completely opposite. So if you go distal side, you should pull the shaft and if you go to the proximal side, you should push the shaft. And so this is the first step marking. In this case, I use the narrow band imaging and I delineate the border of the region like this. And sometimes I adjust the respiratory movement. So if the patient stops, please put the mark like this. And if it is difficult to keep some distance, you should keep some distance from the next mark like this. And after that, you should put additional marking between the two marks. And adjust the respiratory movement. And finally, I add the additional mark like this to identify the direction of the region. If the resection result in the not R0 resection, it is very important to identify the direction of the specimen because the recurrence site can be predicted at the position. And importantly, the distance from the region to the marking change according to the histological type. I put marking from the region 3 mm distance in intestinal type gastric cancer. And for the diffuse type gastric cancer, I make more distance such as 5 mm from the region. Because the diffuse type gastric cancer sometimes extends below the mucosal layer. And next step is the submucosal injection. It is important not to injure the vessel during the submucosal injection. So do not push too much as Daisuke told. Like this. And after puncture, you should control the tip of the needle direction and make homogeneous cushion to make it easy to cut mucosal layer like this. You can see the very nice submucosal elevation is obtained after the injection. And puncture site should be the virtual incision line. Sometimes we cause submucosal bleeding due to the puncture. In such case, if you cut this area, then we can drainage the blood. If not, submucosal hematoma will be caused. And in such case, it is very difficult to identify the dissection layer. So this is a good and bad submucosal injection. In bad case, puncture too much. This cause may injure of the vessel. And in this case, the tip of the direction don't change. You can't adjust the shape of the mucosal elevation. So you can't see the cutting line well. In left side, you can see the cutting line very well. So you can easily cut. So good submucosal injection is the key to success for the mucosal incision. And technical tips of the injection is puncture site should be outside marking and on the virtual incision line. And the conformation of the submucosal injection and the color of the cushion change bluish color. If you inject too deep, sometimes you inject in the muscle layer. It is very rare in the stomach. But in the esophagus or duodenum or colorectum, you may inject into the muscle layer. In such case, the color doesn't change. And after injection, retrieve the needle slowly. This is why to avoid the bleeding and injure the vessel. And additional injection site should be foot of the cushion to make a homogeneous cushion. And the next step is the mucosal incision. And ESD with IT knife family, from the distal side to the proximal side. Sorry, I don't have many pictures of IT knife because we only use dual knife. But mainly from the distal side to the proximal side and makes circumferential incision at the beginning. On the other hand, the ESD with other electrical surgical needle type knife, the cut from the near side to the far side. Because if you cut from the far side to near side, then the tip of the knife goes gradually toward the muscle layer direction. So it is very dangerous. So you should cut from the proximal side to the distal side. So I'll show the technical tips of the mucosal incision. Most important technical tip is keep steady contact to the target tissue and manipulate the endoscope very slowly but steadily. You can see very smoothly cut the mucosal incision is performing like this. And I adjust the respiratory movement. So I stop if the patient respirates. And one point is not to cut too deep. Also, I agree with Dr. Kikuchi. And you can see the vessel is remained. Keep shallow cut, we can preserve such kind of vessels. And unfortunately, sometimes we cause the bleeding during the mucosal incision. Now the bleeding occurs. But don't stop cutting at this time. If you stop cutting immediately after find the bleeding, it is very difficult to find out the bleeding point. Additional cut may make a space to find out the bleeding point. And in such situation, we can easily stop the bleeding. Only tip of the knife in the sheath and just use the coagulation current, we can control such kind of sputting bleeding. This is a good important technical tip for the mucosal incision. And yes, again, don't place the knife too much against the mucosa. This is one reason is for the prevention of the muscle layer injury. But another point is to avoid bleeding. So vessels are existing in the submucosal layer. So if you cut too much, too deep, you can easily cause such kind of massive bleeding. Very scarcely situation. You can't see anything. And after hemostasis, you can see the submucosal hematoma like this. You can't see anything and it is very difficult to identify this dissecting layer. So please maintain, preserve the vessel during the mucosal incision. And next step is a deeper cut. So you can see the blue layer here. This is enough deep. So first step is inject through the knife like this. So you can see blue layer and there is no vessels. So dissect this safety area as a first. After that, you can see the vessel. So use the precoagulation technique proposed by Professor Toyonaga. And you can cut the vessel without causing bleeding. And after that, you continue dissecting. And you can see, if you dissect enough deep, you can see the muscle layer directly like this. So we can dissect this clean layer. In submucosal dissection, So recognize the muscle layer plane and keep steady contact to the target tissue. And slowly, dissection slowly like this using the coagulation mode, swift coagulation. And sometimes I use the additional submucosal injection like this. You can see the muscle layer now. So dissect the lower third of the submucosal layer. Because this area, vessel is sparse. You can see the shallow submucosal layer. There are a lot of small vessels. So dissecting the deep layer avoids unnecessary bleeding. So keep appropriate depth of submucosal dissection. So I think it's safer you dissect the deeper layer. It is sometimes scarce, but dissecting the deeper layer is more safe. And also, if you dissect the deep submucosal layer, you sometimes encounter such kind of penetrating thick vessels. So in such case, carefully pre-coagulate these vessels. Well, this kind of thick black vessels, I sometimes use the coagulator. So grasp the root of the vessel. And white vessel is the artery and red one is the vein. So second grasp is important. Because sometimes after cut, bleeding from the vein side will occur. And in this kind of relatively thin vessel, we can use the forced coagulator effect 0.3. I think Professor Toyonaga will give you a detailed lecture later. I think this is very, very important and very, very useful for the clean ESD. Clean, meek, and less bleeding ESD. You can see there's no bleeding after cutting the vessels. So this is my final slide for the advice for the success. Predict the technical difficulty prior to the gastric ESD, especially the region location and the region characters. And get used to the retroflexion, especially for the region locating on the gastric body. Retroflexion is essential. And good Samuko injection is key to successful Mukosa incision. And dissect as deep as possible for the safety. Thank you very much for your kind attention. Thank you very much for your wonderful talk. We would like to accept a few questions from you. Don't you have any questions? I know that you don't have so much gastric cases here in the United States. But it is very important to know how to conduct gastric ESD. Okay, go ahead, please. Please press the button. Thank you. Great lecture. For gastric ESD, for certain lesions like the ones that you showed, do you generally help perform magnifying endoscopy prior? Because that's not available in the U.S. Second question, do you generally use any PCLE or any other methods to identify those lesions? Can you comment about that? Thank you. For the first question, not always but often use the magnifying endoscope. Many of lesions can delineate the border only by the chroma endoscopy. So lesion for the difficult case, we use chroma endoscopy. Sorry, magnifying endoscopy. What is your second question? Sorry. Yeah, do you generally use any confocal laser endoscopy or PCLE for identifying lesions? We don't use PCLE because it's quite expensive and it's not generally available in Japan. Thank you. Could you use the microphone? Do you use gastric ESD for benign lesions like two centimeters carcinoids or small to medium sizes? Okay. You mean the sub-epithelial lesion? For sub-epithelial lesion, we treat the small net endoscopically. But we don't use ESD because I think two centimeter net, the leaf node metastasis is not negligible. So basic indication for net is lesion less than 10 millimeter. So it can be resected by the EMR ligation. And for the gist, it's arising from the proper mass layer. So basically, ESD is not suitable. Yes, please. Great lecture, sir. So my question is, do you routinely use EUS for assessing the depth? I know with the surface pattern, you can definitely identify how the submicrosial invasion is. But I feel like after finishing my advanced endoscopy fellowship, I was not trained well enough to assess the deeper depths. So some comments on that, how can we get better in it? So for the T-staging, we sometimes use EUS, not all case. I think EUS often over-diagnose the invasion depth. So we perform EUS in case we suspect submicrosial invasion. And if you observe the third sonographic layer below the lesion, it is a sign that there is dissecting layer remained. So we use EUS for the estimation of the dissectability by ESD for suspicious submicrosial invasion cancer.

ESD

gas leak ESD

technical difficulty

stomach region

lateral flex position

submucosal dissection