In the morning, Dr. Adam explained the exosurgical unit, and I wanted to do more case studies and try to think how we can apply our knowledge to make it more successful. This is my disclosure. When we're doing the ESD, the target tissue is so variable. When you see it on the left side, it's a little more fibrotic, but it's a nice avascular submucosal tissue. And here, there's a wide area of the submucosa, so multiple current can be applied. If you want to have a really clean cut, you can do more cut current. Or if you want to just robustly disrupt the submucosal tissue, then you apply the traction and then you can do spray coag. That's one of the faculty that Sergey does. You saw this colonic ESD is kind of blasting and separating. He was using spray coag, but that's really dangerous if you apply in a very narrow area. On the right upper corner, you can see the vessels, so you have to think how we coagulate before cutting through these vessels. So if you apply cut current, you're going to see bleeding. No bleeding is the best ESD. It saves time. It saves complications. And the right lower corner, you see much more fibrosis. It's the more dense fibrotic scars. And to dissect off this area, you don't want to do coagulation. So that's the adjustment you have to start thinking. The ESD is all the conglomerate of this technology and technique. We have to utilize the knives and electrosurgical unit really wisely. And Yusuke explained, there's no one tool that's most suitable. It's your technique, your target, and you have to choose wisely. So pre-planning procedure is really helpful, but in the United States, we cannot do pre-procedure EGD or colon to just make a plan. So you have to really adapt to the situation. And the method, we have multiple methods. We have to use the most suitable ones. If you have traction, it makes everything easier. And kind of a method of applying electrosurgical current changes with traction. To recap, cut current is continuous sinusoidal waveform. That means you just apply the continuous energy. That really brings up the heat so quickly and boils up the intracellular fluid. So it just bursts. You saw the bursting picture. That's a cut current. So it's vaporizing and you just make it disappear. On the other hand, coagulation current is interrupted by very infrequent application of high voltage. So just apply, apply, apply, just a stepwise increase in the temperature. As a result, denaturation happens, dehydrates, shrinks, the shrinkage as Aziz explained. So if you think about it, if you apply the forced coagulation in the semicircular tissue, if you don't have a tension or traction, what you're doing is shrinking the tissue. So if you apply the forced coagulation, try to cut it. If you don't move it, it's going to shrink down and close up the semicircular tissue. So that's what we're trying to avoid. You have to give attention to apply the forced coagulation or otherwise you have to move more towards the cut current. And typical forced coagulation duty cycle is 6%. It's only on at 6% of time. So what we are thinking, what we are thinking about the application of quarteries. The tissue effect is a key. We want to cut the tissue without bleeding but cleanly. Not much coagulation if we can, that's the best. But if there's a lot of vessels, we have to apply coagulation. So that's a balance. The monopolar, you have to go through this very significant tissue. You're working inside the body and you have to, all the electric current have to go return to the return electrode. So this is the resistance we have. And if you contact in a very small area, that increase the current density. All this current apply, focus on this area. That means this energy is focused. It's much more robust. Even though you apply coagulation, the effect of the energy is so focused, it cuts more rapidly. If you have a large area, the contacting, which is coagulation forceps, it's areas is much wider if you apply coagulation with a low voltage, it effectively coagulate, dehydrate, and seal the vessel. Body habitus is really the effect. The electrode, if it's too far, body is so containing fat, the resistance so high, you don't see much of the effect. If you see that, you have to increase the energy. If you have to increase wattage, you have to increase the voltage. To increase the voltage, the effect is the key. If you have a dry cut swift coag, if you're not seeing adequate effect to increase the energy, you have to increase effect. That increase in voltage to deliver much more energy. The wattage, interestingly, I'm explaining it. If you don't understand, please ask me a question. The wattage is the maximum. You're not applying 10 watts, 60 watts. That's the maximum you're applying. Frequently, you're not applying 60 watts. If you go more than 60 watts, it cuts off. This is sealing. Most of the time, if you're cutting, the wattage is 10 watts, 15 watts. It's amazing. The low wattage is really cut because we focus on a very small area. The giving attention really works well. I'm going to explain a little more later. We have to think about what's the body habitus of the patient, where you put the grounding pad, and what's the area filled with, with the blood, water, saline. I typically use the saline for irrigation to make it a little more workable. What of tissue you're trying to cut? If you have a lot of tissue, you're decreasing current density. You tend to do more coagulation effect than cut current. If you want to cut fast with a large device, you have to either increase energy by increasing voltage or do more cut current. If you do that, you have to be ready to cope with the bleeding because you're cutting with a large tissue, you might be cutting the blood vessel at the same time. In the surface area of the surgical device, we keep talking about this current density. How much of the target tissue you're getting is really the key. You have to see what you're cutting. That's the visibility we're stressing on. Put the cap, see the target, see the tissue, how much you're getting. Then you apply how much tension. If there's a little bit of tissue, if you have a tip of the knife, even forced coagulation would disrupt the tissue and make it go away. If you have much of the tissue and if you coagulate, you shrink the tissue. You cannot really cut. At the same time, if you push with the forceps, I mean the knife, give tension, tension would be disruptive. If the tissue gets dehydrated, it just disrupts. Think about the snare polypectomy. If you're doing the polypectomy, you can do the forced coagulation, right? That's because we're applying the force with the closure. Closure actually cut through when applying the coagulation effect. That's the key. If you don't close the snare, you keep burning the tissue. That's why you have to ask the technician or assistant to close the snare first to apply forced coagulation for polypectomy. Endocut is a different thing. Endocut keep cutting through the tissue, vaporizing. So whatever it touches, it try to cut through. So snare polypectomy, if you do an endocut, you work with the snare. You just keep closing, continuously applying some of the contact. It's not constricting. It's contacting, then make it cut. That exactly apply to speed of movement. How much of the tension you have, how much keep cutting, that defines how much energy you have to apply. Traction make it so much easier, so more of the coagulation current can be applied to disrupt the tissue when there's more traction. Now electrosurgical unit is getting smarter and smarter. So do you have any preference where you put your grounding pad when you do the upper jaw versus colon? So probably most muscular area in closest to the body. I typically put under the back, and Irby tend to just advise against. And you have to make it more perpendicular, because you don't want to have the corner having a return current. That can cause a burn on the skin. So probably it's the thigh or back on the muscle, trying to be more perpendicular to the direction. Does it make sense? I do tend to put it under the back, closer to the body. If I'm doing the esophageal ESD, I put it on the back. For the colon, probably thigh would be more adequate. And you have to see, the counterbalance is increasing the voltage. So if you see that the effect is not adequate, you can increase the effect. And see if you can get the adequate effect of the tissue reaction. So talking about VIA 300 versus VIA 3, we're talking about the newer machine. This upgraded machine has increased computerization. It's just the chip is so smart. The computation used to be 200 per second. Now it's 25 million per second. So it keeps adjusting to the return and the resistance. That kind of gives us a little confusion for us, but I'll try to explain to you in my way. So PreciseSec is an automated mode that they created. So whatever they touch, they try not to char, coagulate adequately, and cut. So it's automated mode. I know the Japanese masters doesn't like it because it's just more of an automated system that you cannot really adjust. I realize that if you don't touch the tissue, they feel like there's a lot of resistance. So they increase the voltage and sparks. And I see the premature cutting of the vessels because the energy is so much robust. It's like more spray coagulating when I don't want to do it. So you have to keep touching the tissue. That really needs a trust. Does it make sense? So PreciseSec, we're still struggling how to use it because this is a little more different than we have learned how to do it. Much more targeted capture. We see what you want cut with a dry cut or cut with a spray coagulate. That's what we have learned. But PreciseSec is supposed to be anybody's game. So if you keep touching and moving, it's going to do its job. And we're still finding out how best, what's the energy delivery, what's the wattage. It seems to be lower energy is adequate for ESD. But when we find out, we'll let you know. But that's an automated mode that they keep calculating. There are two things I want to say that power assist, the EndoCut has a power assist. So at the beginning, when you touch the tissue and apply, automatically it just increases the voltage. So it's going to immediately start cutting and then control to the level. So it's really nice cutting. If you tap, you're using the power assist anytime. So if you're cutting through the fibrosis, that's the best way because you vaporize, you just make it disappear. It's more like it's kind of exploding every fiber without coagulation. And that's really nice control. Now the new VIO3 has auto-start for soft coagulation. The soft coagulation used to be more of a slow increase in temperature. But now auto-start would increase the power at the beginning. So it just immediately stopped bubbling. So that's maybe the nicer control. You don't have to wait for a long time. Once it's bubbled, you're done. So you have an option to do the auto-start or not do the auto-start. So you can select either way. So may I give one comment regarding auto-start? Yeah, please. Because soft coagulation is kind of a slow-acting coagulation current, and in case of spending so much time, temperature is slowly increasing, but at the same time, temperature goes deeper. So if we spend so much time using soft coagulation, it's really dangerous. It causes deep thermal damage. That's why I strongly recommend you to use auto-start. It's really nice. Great comment. So if you do a low wattage and go slow cooking, go deeper and wider. So typically 80 watts, we don't use that 80 watts, but it coagulates quickly and it stops going deeper. So that's why the quicker the coagulation, it's safer because it doesn't go deeper. Bipolar device is available. By the way, the new device, the wattage is here. I know there's a number, very fine adjustment you can do, but you can refer to this wattage so you can adjust. There's a guidance in the wattage. We talk about 2.6, 2.7. Actually, whatever you feel is right is the right number. The bipolar device may be another device that we want to have in the ESD. There's a B-knife is available in Japan and now a newer bipolar device is available. The benefit is the circuit just concludes in the local area. So it doesn't go through any of the body. So it's much more predictable energy effect. It uses only one-tenth of a voltage to cause the same effect that you would want. So it's much more clean cut, predictable effect, and it cuts through the fat. It's really nice. And the newly available microwave coagulation has a really good coagulation effect. I want to just do the video, so I'm going to just skip through some of the things. The B-knife definitely calls for a different setting. We have a variety of the shapes and the length, and the scissors typically have a much more contact surface. So you tend to do more coagulation than the cutting. So you call for endo-cut rather than cutting or coagulation current, like dry-cut or sweet-coag. Cut and coagulation is not simple anymore. Typically, the sweet-coag is a little more cutting than the false-coag, but more coagulation than dry-cut. So those are the kind of separation. Endo-cut has a mixture of cut and coagulation in a computated mode. So you can increase the coagulation effect by increasing effect. Effect doesn't affect the voltage in this endo-cut. Endo-cut if you increase effect, increase the coagulation in between. So if you see every time you cut with endo-cut, you start seeing bleeding, you may want to increase the effect and see. And slow down the speed, that increases coagulation. Cutting is better for mucosa, fibrosis, dehydrated tissue, you're going to char more with the coagulation. And in blind-stained SMs, we heard about hematoma. These areas, if you do the coagulation, you see chars and shrinkage, you just make it more complicated. I explained to you about the polypectomy and the area of surface submucosal space. If you have really good tension, you can use more coagulation effect. And you can just really go fast, because cut current doesn't provide much of the coagulation. But with the tension, coagulation, you can achieve both coagulation and cut current at the same time. The speed is a key, actually. If you give a little tension, more tension, you cut more, you're faster. But if you want to have more coagulation, you have to move slower. So that's the speed, depending on your technique. And always reassess how much of the tissue effect you're achieving, and then you adjust changes. I have four, five different settings, I'm always switching around depending on the tissue reaction. So with a limited time, I'm going to show some of the videos. This is soft coagulation, it's a non-char mode. The low voltage, less than 200 voltage. So it really works well for marking and tissue vessel sealing. Now, mucosal incision, I prefer end cut. I think, now he said you do dry cut for colon, correct? Yes. And end cut. For upper, I think end cut works better. For squamous mucosa, if it's not thick, it really works well with the dry cut as well. But for barrettes, the mucosa is too thick to cut with a dry cut, unless it's not really thick. We heard about cutting shallow, and I tried to do the same, not to see the bleeding on the mucosal incision. And here, I just wanted to show that the speed actually changes the coagulation effect. I thought it was much faster. Here's a muscular mucosa, so once it's exposed, I'm going to change to the swift coag if there's a blood vessel. But here, I don't see blood vessel, so I'm using a dry cut, or end cut, if it's continuous. The semicosal dissection here, I changed the dry cut, because I don't need the end cut for semicosal dissection. I can control better with my tapping. And there's very sparse blood vessels, so the cut current is much cleaner. And once you go into the semicosal space, I see much more fibrosis. Here, I don't want to do coagulation effect, because even swift coag in this area, probably it's going to shrink down and char, and make it inseparable from muscle to the semicosal layer. And here, I tried to cut just above the muscle. There's a small muscle injury, so you have to be very careful how to dissect this area. Other alternative is close the knife, using only the exposed tip of the dual knife, and do the end cut. That's also described as well. Let's see. Dr. Yamamoto, what kind of current would you use here? I would use end cut with duration one. Just a short duration, to make sure. If you use a duration, a longer duration, you can cut to the muscle layer, maybe. So the short duration end cut is my preferred. I prefer to use dry cut. Do you move faster? Oh, yeah. The next is the blood vessels. I changed the swift coag. I wanted to go slower, but unfortunately, I cut too prematurely. And here, you can use the precise sect or force coag with a needle tip, and apply very gently at the top of the blood vessel. The problem is, if you go onto the blood vessels here, the tip is closed, by the way, you are on the muscle. So you may just injure the muscle layer. So alternative is change the coagulation forceps. I usually use a very low setting of spray coag in this situation. Just using closed tip of dual knife, and apply 1.2 of spray coag. That usually works very well. What's the wattage? Like 10 watts? 1.2. And then Bio 3, right? No, no. 1.2 watts. Bio 3. Bio 3, 1.2. Bio 3, 1.2 spray coag. So very low, those spray coag can be used. Do you stop just before the blood vessel touches? Just barely touches? Yeah, yeah. If you do tension, it's going to slice open and cause bleeding. So you have to be gently touching when you're applying coagulation. Here, oh, this was an example, I know this is a little bad example. That was a precise sect. I tried to cut through, but with the habit, I stopped just before, and the precise sect causes a spray coag, really robust spray coag, just slice it open. So if I have to trust the precise sect, I have to keep moving like that, just keep moving slowly and keep applying. So precise sect is really nice for surgeons, because they can see, they keep cutting like a knife. But for ESD, since we keep tapping to control the cut area, it's a little more cumbersome to use. But still, I continue to keep trying. This is the effect that I'm exposing the vessel and trying to do force coag, low dose force coag, 10 watts, effect one. But the problem is, I couldn't really get to the side of the vessel and compress. And as you can see, you're not seeing the sealing effect adequately, because I'm not giving adequate tension to seal off the vessel. If I want to do it, you have to go from left to right towards the lumen, and right to left is going onto the muscle. So I'm struggling to really find out what the best way. But because of the respiration and heartbeat, I couldn't really get that. So in impatience, I did the precise sect and just blast it off. This is the effect I just wanted you to see. This is the blood-containing submucosal area. And then you see that if you keep applying coagulation current, it just starts charring. You cannot see. One more tip is soft coagulation can be applied under the water. If you really cannot see the bleeding point and trying to get the bleeding point precisely, you keep putting it with the water. Now forceps grabs the blood vessels, and you can coagulate under the water. The only thing is you have to apply it a little longer, because the effect is kind of dissipate away with the blood vessels, I mean the fluid inside. Is this saline or just water? It is saline. Saline? Oh, really. If you use saline and coagulation forceps, then the electric current goes around the saline. So it took a little longer time, but you can do under just the saline water as well. It's probably much more concentrated within the forceps, as you mentioned. In case of using coagulation forceps under water condition, it usually doesn't work well. That's why I usually suck the liquid as far as possible after catching the bleeding point. Otherwise, we can use bipolar forceps. It perfectly work even under water condition. Bipolar forceps? Bipolar hemostatic forceps. It is much ideal situation to use it. I think we don't have that force yet. Pentax already have bipolar forceps. I developed it. I hope we have that in future. These are really thick vessels, multiple artery in the vessels. You definitely need to pre-coagulate with forceps. So I think I went over time. This will be available for you online. This is my setting. And then there's a comparison chart. You can just refer to this. And this is Olympus ESG, the old one and new one. There's multiple settings available. You have to really see which one is more cut forward or coagulation forward and adjust to the tissue effect to achieve the optimal outcome. Thank you. Thank you very much. Thank you very much for your very...

exosurgical unit

case studies

ESD procedures

fibrosis

submucosal tissue

currents