Okay, good morning. I'd like to talk about the pocket creation method. Can I? Okay. First of all, why do we do ESD? That is the treatment for cancer. What do you need to cure cancer? Cancer is a life-threatening disease for the following two reasons. One is the unlimited growth and the other is metastasis. Therefore, in order to cure cancer, we have to resect all the tumor entirely and still that is not good enough. If there is a risk of metastasis, it's not curative. So we have to select a region which doesn't have a significant risk of lymph node metastasis and perform R0 resection. So what are the benefits of ESD? Using ESD, we can get a reliable envelope resection with R0 resection and because of that, low risk of local recurrence. And we can get a high-quality specimen for histopathological examination. That is necessary to predict the risk of lymph node metastasis. And after careful pathological examination, we can make sure that the treatment was curative. Okay. This is the cancer. If the cancer invades to the submucosal layer, then there is a risk of lymph node metastasis. And the depth of invasion and lymphatic involvement, vessel involvement, those are the factors to predict the risk of lymph node metastasis. This information is in the submucosal layer. So we have to get a good specimen with enough submucosa. That's very important. So the vertical margin is very important. That's the reason why I perform pocket creation method. Using the pocket creation method, I can select the dissection plane right above the muscle layer and getting enough submucosal tissue on the specimen. So we can get a very good specimen for the pathological examination. That is the main reason why I perform pocket creation method. But there are several other reasons. As you know, for those who perform POEM, once you go into the submucosal space, then you can get a very stable control of the endoscope. So it is very stable in the submucosal pocket. Then the selection of the dissection plane becomes very easy. And the recognition of the blood vessels is also easy. So recognize the blood vessel and isolate the blood vessel, coagulate the blood vessel before cutting. That way, you can prevent bleeding. The prevention of bleeding is a very, very important factor for successful ESD. And using the pocket creation method, I just make a mucosal incision for the entrance of the submucosal pocket. That is about two centimeters in depth. And then I perform submucosal dissection before making the circumferential mucosal incision. This is a key feature of the pocket creation method. And completion of the submucosal dissection before cutting the mucosa. In this way, we can get a very clear and vertical margin that is good for pathological examination. And open the pocket and finish the procedure. This is the pocket creation method. And for the pocket creation method, I use the ST hood. That hood is a special hood narrowed down to seven millimeters at the tip of the hood, the cap. And using this cap, the knife comes to about the center of the opening. Therefore, even if we locate the region at 12 o'clock, still we can select the dissection plane close to the muscle layer. And this is the first publication I made in 2003. And this time, I made the ST hood myself. And using this ST hood, entering into the submucosal layer and dissect under direct visualization. And the successful ESD was completed in both the stomach and the colon. And then I made the technique to the tunneling method. But this is the publication in 2010. But I changed the name of the technique to the pocket creation method. That's because I realized that completion of the tunnel penetrating through the other entry is sometimes cumbersome and not necessary. And it is more important to widen the pocket to complete the submucosal dissection under the tumor than to complete the tunnel. So with the name of tunneling, completion of a narrow submucosal tunnel from one entry to the other is emphasized. However, with the name pocket creation, widening of the submucosal pocket to complete the submucosal dissection can be easily imagined. So the dissection, getting a good vertical margin is the purpose of the pocket creation method. And using the pocket creation method, we can keep a good submucosal elevation throughout the procedure. And we can easily apply traction and counter traction with the cap. And the direction of the approaching angle can be adjusted if the endoscope is in the submucosal pocket. And even if the target organ is moving with respiration or cardiac heartbeat, once you go into the submucosal space, it stops because it moves together simultaneously. So it looks like it stopped completely. And you can get a stable condition. And how to perform pocket creation method, I want to show you. This is Dr. Murai. He looks young. Anyway, injection. And first injection, pull back the needle and make a good protrusion. And after the initial injection, I insert the needle at the base of the protrusion. In this way, I can secure the submucosal space without injecting into the muscle layer. This is the first step. And after making a mucosal incision, the first dissection is just with the tip of the knife. Don't use the hood yet. Just with the tip of the hood. And we can use the tip of the sheath to elevate, pull up the mucosa. And several times, a few times dissection, then using the water jet, and open, and go into the submucosal space. In this way, we can go into the submucosal space easily. And Dr. Yahagi calls this method the water pressure method. Using the water jet, the opening of the inside the mucosa is easy. Then after going into the submucosal layer, then come close to the muscle layer. And after we can see through the muscle layer, I inject the fluid right above the muscle layer. In this way, we can see the muscle layer very clearly. And especially in the lower rectum, you have to know that the muscle layer is not continuous like this. So if you inject the gap between the muscle fibers, like here, then you can open the gap and dissect there. Without cutting any muscle layer, you can go out of the wall. So you have to know this anatomy. We reported that this is similar to the window blind, like window blind. So we have to know that. And anyway, recognition of muscle layer is very important. How can we do that? That is by changing the direction, like this, swinging the tip of the endoscope with the ST hood. Then we can see through the muscle layer. And we can get a good idea how the muscle layer is going. Then select the dissection plane, leaving a little bit of submucosal tissue on the muscle side. And 2 thirds of the submucosa is on the specimen side. That is a good dissection plane. And how to measure the depth of pocket? I compare the depth and insert the endoscope to the end of the pocket and place the index finger to the anus or mouthpiece. And pull back. And the same distance, I insert the endoscope outside of the pocket and compare the depth of the pocket and the size of the lesion. In this way, we can match the depth of the pocket to the size of the lesion. And another information is the color change. After the submucosal dissection is completed, then the area becomes a bit brownish because of the ischemic change. So this information is also useful. And this is what I do. Insert. And I place the finger to the anus and pull back. And check the length. And this is good enough. Then depth is good. Then I check the width. This is the left edge. And check the pocket. It's wide enough on the left side. And then I check the right side as well. And for opening the pocket, open the pocket. I remain the intact mucosa. So before starting the opening of the pocket, I inject the mucinous substance to elevate the mucosa as much as possible. Open inside the mucosa. And the dissection is from inside of the pocket to the inside of the mucosa, to the luminal side, like this. Hook the fiber with the tip of the knife and move the knife towards the mucosal incision, like this. In this way, the pocket opening is safe. Mucosal incision. And then hook the fiber of the mucosal tissue and open, like this. Okay, that's it. Thank you for your attention. Any questions from audience? Go ahead. Is there any specific situations you think that the pocket creation method is not feasible or can be difficult? Not many. Not many. Actually, I use pocket creation method for almost all ESD procedures. But the bottom of the fundus, that pocket creation method is very difficult. But other than that, not many. But sometimes just using pocket creation method is not good enough to overcome the difficulties. In that case, I combine with traction method. Traction or pocket creation method and traction method can make the procedure much easier. So sometimes I combine. Okay. When you're making pocket or tunnel, do you feel sometimes that you can overshoot and go farther than the proximal or the oral margin and keep digging inside, specifically if you're not careful or there's no blanching on the mucosal side? Right. And you are struggling where to open, come outside. Right. So that happens. So I carefully check. And the pocket, the depth of the pocket, not necessarily exactly match the length. The approximate matching is good enough. And opening the pocket, and if that is not deep enough, then you can add some dissection and make a little bit deeper. So it's not necessary to match exactly. How often do you come out and check? How often? Okay. It depends on the size of the region and the situation. And whenever I feel this is good enough or I feel uncomfortable, am I making to the right direction or not, then I just check and go in again. I don't set a number. And also, when you do the pocket creation, do you have any additional length that you start distally or distally close to your side or the same as regular ESD, the margin? You mean from the edge of the tumor to the entrance? Right. It takes a little bit longer, because to go to the entrance, it takes a bit long. So I make 5 to 10 millimeter, about 7 millimeter distance from the edge of the region. I make the entrance. Thank you. Once you're in the pocket, dissection is very safer and easier. But struggle has been after you finish that part, doing the circumferential incision has been a struggle. I saw what you said, but what are some tips regarding once you have done the dissection? I worry like once I have dissected beyond the lesion, now I'm cutting the margin. I worry that when I'll cut, now there's no submucosa there. So can I injure the muscle, because mucosa and muscle are very close? Or can you cut from inside out if you are comfortable that you're beyond the lesion? I don't cut inside out, because I can't see the edge of the lesion. So the mucosal incision is made from the outside. But if you create the pocket too wide and no submucosa on the cutting line, and then, as you said, the muscle injury could be a problem. But if the lesion is located the upper side, then the specimen hangs down. So as long as you don't push too much, just touching and making mucosal incision, it's safe. And if the lesion is on the dependent side, then underwater and buoyancy makes the similar effect. So in that way, you can prevent. And using the enduro knife or flash knife, the knife should be used to cut to this direction and pulling up the mucosa. And in that way, you can avoid cutting the muscle layer. OK? So you said you use it pretty much for any SD. But what's the lower size limit? Obviously, for larger sizes, it makes sense. Two centimeters. So as big as your entry point is, basically. Yeah. If the lesion is two centimeters, and the opening of the pocket is about two centimeters, the same. But even for smaller lesion, like one centimeter, if that has a severe fibrosis, I still use pocket creation method. Even if I dissect larger than the size, but creation of the pocket to the both sides of the fibrosis, then the dissection under the lesion becomes much easier. So virtually, no limitation. Thank you very much. Thank you.

endoscopic submucosal dissection

cancer treatment

pocket creation method

tumor tissue resection

metastasis prevention

pathological examination