So I'm with Dr. Akimoto from Keio University. And then, so we have dual knife and then needle master here. And then Dr. Akimoto will be showing his technique in the water pressure method. OK. Good afternoon, everyone. Today, I will show you the water pressure method in the stomach. Now, this is a target region. This target region is located on the lower part of the gravity. So I inject the solution into the distal side. OK. Needle, please. So as you can see. Yeah, please. Needling, please. Yeah, inject. Please wait. Sorry. OK, needling. Injecting, injecting. Good, good, good. OK, please, please, please. Thank you. Next. So usually, we perform the ESD initially to making some mucosal flap. Mucosal flap, OK enough. However, in the water pressure method, in the underwater condition, we can make the distal side of the mucosal incision fastly. Please, injection. Injecting, injecting, injecting. So after distal incision, we made the underwater condition to make the circumferential incision. After that, I make the mucosal flap. This is different from the conventional style. However, in the underwater condition, realize that this technique. So I fill the rumen with water now, and suck the air in the stomach. Today, I use the stomach. However, underwater pressure method is useful for the esophageal region and the colorectal region. Because the stomach region, sometimes the heavy breathing occur. Breathing mix the water, so it prevents endoscopic view. So if the region is located at the anti-gravity side, do you reposition the patient? Yes, of course. But endoscopic maneuverability is prior. Now, you can recognize the marking. And I cut the distal sides from here using the DL knife J. What's the reason why you're going to start the distal incision? Distal, yeah, yeah. And in the underwater condition, after making mucosal flap, the mucosal flap overhangs the distal side. So we can recognize the distal side. So I put the mucosal incision on the distal side firstly. Oh, OK. So once you inject proximally, you won't be able to see the other side. So that's why you will finish. Yeah, yeah, yeah. OK, thank you. So check the, OK, I lost the marking. OK, here. So bubbles sometimes prevent the endoscopic view. So I flush the saline using the water jet function of the endoscope like this. And I cut the mucosal and flush the saline. Saline. Sorry, the cut, more cut, the. Ah, sorry, I've changed the. OK, thank you. So Dr. Akimoto is working on the gravity side. So I switched the grounded part to the gravity side. So probably this is probably better. OK. OK. Too strong. OK. So now we saw the spark, so it worked. So always use the saline. We need electrolyte for the electricity. Yes, that is very important. So bubbles flush. Hmm. It's not cutting. My beard... It's not sharp enough. This is the merit of the underwater condition. In the air condition, we cannot recognize the submucosa layer clearly. Just cut the mucosa. After just cut the mucosa, OK? So you can see that the water is giving you a magnified view. It's very clean. Yeah, yeah. So I use, today, the short type ST foot to keep the clear view. So straight type is too short in the underwater condition. So I can show the really clear submucosa layer like this. So it looks like the underwater condition gives some light refraction, which makes the view of your cap worse. So in this case, Dr. Akimoto is using the ST foot, which has a longer portion of the cap. And then you can clearly see the circle at the tip. OK, I can make the half-circumferential incision on the distal side, OK? Okay, next, it's time to circumferential incision after injection. Perfect. So, Dr. Akimoto, I think Keio University started using this technique for duodenal ESD. Ah, yes. And then now you are using it for? Yeah, applying for the colorectal region. So, water pressure method is developed to overcome the difficult duodenal ESD fastly. So, it's same situation between the duodenal ESD and the colorectal ESD. We apply this technique for the colorectal region. Okay. Needle out, please. Please, injection. Injecting, injecting, injecting, injecting. Okay, enough. Next. Okay, please. Injecting, injecting, injecting. Okay, enough. Okay, it's time to circumferential incision. In the water, the pressure of the lumen is very low compared to the air condition. So, the region, the lifting of the region is very good and keep long time. Yeah. So, expansion of the stomach decrease the lifting of the submucosal layer. So, I start the cut from the oral proximal side. So, that doesn't work. Okay. Let me double check again. I lost it. Okay. No, no, no. I lost the region. Okay. Yeah, perfect. Yeah, yeah, yeah. Okay. Okay. So during the morning session, we saw that all the faculty tried not to insufflate too much. But Dr. Akimoto is, because this is underwater condition, he's not insufflating at all. So this is the biggest advantage of the water pressure method. Okay. Sorry. Okay. For some reason, it's not working. Do you have a new knife? Another knife? Please, new knife. Do you want to try a flash? Well, I'll make it a little stronger. Yes, please. So, now we can clear the... Sorry. Mucus prevents me. Just I cut the mucosa, but you can see the clear sub-mucosa layer like this. So it is very easy situation to make the sub-mucosa flap. However, I complete the circumferential incision first before making mucosa flap. We check, check it, okay, last part, okay. Okay, I finished the circumferential incision. Now, I make the submucosal flap. However, already make the mucosal flap like this, so using the water pressure method, using the water jet of the endoscope like this, so open the submucosal layer and dissect immediately from here. Mucus is present, okay, I continue the procedure. Okay, so flush the saline, and next, again. So, when doing the water pressure method, I feel like if you use the coagulation current, you will have a lot of bubbles, so I prefer using endocut like you're using. Yeah, I strongly agree. So, we can recognize the vessel in the submucosal layer, so today, there is no vessel. However, if you use the coagulation mode to the submucosal dissection, the bubbles, more bubbles is made, and it's prevent, and the submucosal tissue shrink because of the coagulation mode, so cut mode is better. However- Can you show what happens with you? Okay, okay. This is swift mode, yeah, bubbles coming, okay? So you can see a lot of spark, and then they evaporate, but as long as you don't see any blood vessel, it's safe to use the endocut. So, good mucosal flap is made like this, so I continue dissection. So, this is a very important part, using the water pressure method, and check the edge of the part like this, so we should cut and dissect the edge part of the submucosal layer like this. Okay, and when you dissect the, sorry, okay, when you dissect the only center of the region, it make mucosal tunnel or the pocket. However, this region is very small, so the region don't need mucosal pocket or tunneling. So, I feel like coagulation forceps is a little difficult to use under the underwater condition because the surface area is very large, so it doesn't conduct any electricity. So, in that case, do you return to the, like, under air or CO2 condition? Yeah, but the air knife can stop the bleeding in the underwater condition using the closing tip of knife. Okay, I will show you that. Please close the tip of knife, and please use the spray coagulation mode, and okay. I recommend the spray coagulation mode, if it, sorry, I don't remember in the bio 300, sorry, but I close the tip of knife. I estimate that this target is a bleeding point, bleeding point, so close the tip of knife and using a spray mode, that's enough to stop the bleeding. Oh, thank you. Yeah, it's very helpful. So, only when you need forceps, you will switch to the air, but most of the bleeding can be stopped by using this, close tip of the dual knife with a spray cord. Yeah, but of course, major bleeding cannot stop the tip of knife, so I have to use the hemostatic forceps. When major bleeding occur, I check the bleeding point in the underwater condition and grasp the bleeding point, and suck the water and the sense the air. Okay. Okay? Perfect. Or you can use bipolar hemostatic forceps in the underwater condition. Okay. So bipolar forceps is very useful in the underwater condition, because what electrolyte of the blood of the saline does not prevent the electric current of the bipolar hemostatic forceps. Oh, that's a great point. Thank you. Okay, almost finished. So using water pressure, I check the end of the region and dissect the last part. Okay. Okay, almost done. Okay, finished. Excellent, beautiful. Thank you. Thank you very much. Yeah, beautiful. I promise that this technique is very useful for the chronic or correct esophageal region. Okay. If you use esophageal region, it has risk of aspiration pneumonia, and I recommend intubated general stage. Okay. Okay, thank you very much. Thank you. Thank you very much, Dr. Akimoto. Thank you. Thank you very much.

water pressure method

Endoscopic Submucosal Dissection

underwater conditions

mucosal flap

general anesthesia

Keio University