Welcome to ASGE Endo Hangout for GI Fellows. These webinars feature expert physicians in their field. And I am very excited for today's presentation. The American Society for Gastrointestinal Endoscopy appreciates your participation in tonight's event, Can GI Do That? Understanding Interventional EUS Third Space Endoscopy. My name is Michael Dellutri, and I will be the facilitator for this presentation. Before we get started, just a few housekeeping items. We want to make this session interactive, so please feel free to ask questions at any time by clicking the Q&A feature at the bottom of your screen. Once you click on that feature, you can type in your question and hit return to submit the message. Please note that this presentation is being recorded and will be posted at GILeap, ASGE's online learning platform. You will have ongoing access to the recording in GILeap as part of your registration. Now it is my pleasure to turn this presentation over to one of our GI Fellow moderators, Dr. Faisal from Henry Ford Health in Detroit, Michigan. I will now hand over this presentation to him. Hello, everyone. I am Salman. Thank you all for joining, and thank you to ASGE for organizing this incredible platform. As Michael said, I'll be moderating this session and keep an eye on your questions. We can make it as interactive as you wish, so feel free to contribute with your questions and comments. We'd love to hear from you. We have two incredible speakers today who are both not just incredible doctors and leaders in the world of advanced endoscopy, but also great speakers. So they're here to tell us a little bit of what GI can do. It is my pleasure first to introduce Dr. Ryan Law, who is an associate professor of medicine and consultant at Mayo Clinic in Rochester, Minnesota. Thank you, Salman. I appreciate the introduction. I appreciate the opportunity from ASGE to ask me and Amritha to speak. The way I'm going to speak about interventional EUS, and then Amritha is going to speak about ESD in third space, or Pullman in third space endoscopy, the way I kind of set this talk up was a bit to just give an overview of all the kind of therapeutic EUS procedures that you may come upon during your training or once you're into clinical practice, realizing that these are generally higher risk procedures, maybe not something that you venture out into on your own in fellowship or early in practice, but something to build to because they are incredibly powerful for patients and currently part of our developing landscape in therapeutic EUS. We'll spend a few minutes talking about pancreatic and biliary rendezvous before switching gears and talking about true drainage procedures of the bile duct and the pancreas. And then the goal will be to finish with luminal access procedures like edge procedures, gastroenterostomy. And then if we have enough time, I have a couple kind of quick cases at the end, which I think are just fun and just kind of really show what we actually have capabilities to do in current practice. So briefly, just historically, we think about commercialization of endoscopic ultrasound with the first radial scanning EUS scope in the 1980s, followed by the linear array EUS scope and then EUS fine needle aspiration in the 90s. And then since that time, we've seen a kind of a consistent and direct shift where EUS certainly still has a diagnostic role, but its therapeutic capabilities have become more evolved and elegant. And again, just great opportunities to help patients in a minimally invasive fashion. The first EUS guided cholangiogram was actually here at Mayo Clinic in 1996 by Moritz Wiersma. Mark Giovannini in Marseille did the first EUS guided biliary drainage procedure, followed by another French group doing the first EUS guided pancreatic rendezvous in the early 2000s. As well as pancreatic gastrostomy in 2002. Sean Mallory and the group at the University of Minnesota did the first EUS guided biliary rendezvous in 2004. And I think it's important, you know, as fellows to understand kind of where we came from and where the roots of these procedures you're seeing are. They didn't come out of thin air. They came with a lot of thought and a lot of development and care to determine, you know, what our capabilities could be and how they can be harnessed to gain the most advantage for patients. Now, things you need to be aware of for therapeutic EUS. I'm sure most of you are familiar with the stent on the left panel, which is a luminoposing metal stent. The only luminoposing metal stent currently FDA approved in the United States is the Axio stent. It's approved for gallbladder drainage and drainage of pancreatic fluid collections with a potentially impending indication for EUS guided gastroenterostomy. On the right panel, you'll see a variety of fully covered or partially covered self-expandable metal stents used in biliary drainage. Mostly can also be used in pancreatic drainage, but these are also important and something you may see. With that, we'll kind of move on quickly to indications. Indications for pursuing kind of EUS guided drainage procedures or EUS guided access procedures really comes from the concept of failed conventional ERCP and why it's failed may be a variety of things. It may just be a routine failed cannulation. It may be an inaccessible papilla due to surgically altered gastrointestinal or pancreatic or biliary anatomy. There may be a malignancy precluding access to the major papilla. Historically, when these procedures first were being developed, there was a kind of a very soft indication that there should be a contraindication to percutaneous interventions. Overall, I think that that's not necessarily true anymore. I think the literature has borne out that these procedures are exceptionally powerful and useful for patients and not necessarily something that should only be done as a salvage procedure if interventional radiology is unsuccessful. Now, when we think of the most kind of commonly surgically altered anatomy, we see where some of these procedures may come into play. Certainly, patients with Whipple anatomy following a pancreatic head resection. There's less and less patients we're seeing with Biliroff 2 anatomy. For those of you who are young enough, you may not even realize what a Biliroff 2 is. It's an antrectomy with subsequent end-to-side gastrogynostomy. Very similar to Whipple anatomy when you're performing endoscopy except generally there's an intact papilla leading to the bile duct and the pancreas duct. Certainly, Roux-en-Y gastric bypass is something that we're all seeing quite frequently and will continue to see in substantial numbers. Less commonly but still something that we do see is a duodenal switch. Duodenal switch procedures tend to be very difficult to intervene on from an endoscopic perspective if you're trying to do any pancreas or biliary work. The other anatomy you should be very familiar with is a non-gastric bypass Roux-en-Y. Patients who've had a total or subtotal gastrectomy after gastric cancer, patients who've had a liver transplant for PSC and are reconstructed with a Roux-en-Y hepaticogenostomy are kind of the most common ones in that general group. Then the final group of patients who we've all seen and are incredibly difficult are the patients who've had multiple surgical revisions of their either pancreatic biliary anatomy or their luminal anatomy. Patients who when you scope them all you do is find anastomoses and multiple limbs taking off those anastomoses. Those are also patients where EUS guided approaches may be really your best option because trying to find how they were reconstructed and getting to any sort of normal structure is challenging. Now I tried to do this in a systematic approach and like I said this is more of an informative talk. It's not going to be necessarily data-driven. More of just to kind of overlay what these procedures are, what they mean, and kind of provide a framework for when you hear them or read them in the literature. So an EUS guided biliary rendezvous, basically this is an EUS procedure where access is gained to the bile duct either from the extrahepatic bile duct or from the left intrahepatic bile duct more commonly than the right. An FNA needle is used to puncture the duct under endosonographic guidance. Contrast is injected using fluoroscopy and then subsequently a guide wire is passed anti-grade through the papilla or an anastomosis generally into small bowel. And what this does is the guide wire then is left in place and the echo endoscope is then removed and replaced with a standard duodenoscope with the idea that the guide wire can either be utilized as a guide to tell you where you need to use your ERCP device to gain access to the bile duct or it can be used directly by retrieval of the guide wire and then advancement of catheters or sphincteratomes or what have you over the guide wire to perform your interventions. Either is appropriate. I tend to use alongside the wire first and then over the wire if necessary but neither is wrong. In my practice this is generally only performed for benign disease. I don't like to do this approach for malignancy because I would just rather drain the patient and not risk any sort of bile leak or less of a bile leak or any challenges with fighting a wire through a very tight stricture. So this tends to be for patients who maybe have a diverticulum that's associated with the major papilla or a stone that is obstructing and you're unable to cannulate but generally in benign disease at least in my practice. Reasonably high success rate of doing EOS and ERCP of greater than 80 percent with an acceptable adverse event rate mainly due to bile leak and some bile peritonitis around 10 percent. Here's a video. You see the extra hepatic duct there with kind of a puncture of the duct. Contrast is injected and then subsequently the needle is flushed and a guide wire is advanced. I can tell you this is a well edited video that is never this easy. Amrita can attest to that later. The guide wire is left in place. The EOS scope is then removed and the ERCP scope is advanced alongside it. In this case we did decide to utilize the guide wire. Subsequently gained access to the bile duct and then placed a stent and I think this is a patient if I remember correctly with cholangitis. So you see some not great looking material draining from the bile duct. Dr. Lopp sorry what's size of the needle and like the wire through it do you use to puncture the extra hepatic body? With any excuse me with my with therapeutic EOS for me it's a 19 gauge needle with a with a 0.025 inch angled guide wire long angled guide wire through it. You can use smaller needles. You can use a 22 gauge needle and an 018 guide wire. It's very difficult to work over an 018 guide wire and sometimes even the concept of using a small wire and then exchanging to a bigger wire sounds easier than it actually may be. So I like the benefit of a pretty stout wire and a big needle to make sure I can gain access. So as a corollary to to biliary rendezvous this is pancreatic rendezvous. This is generally performed by puncturing the pancreatic duct typically in the body near the neck. In most patients similarly a USFNA needle obtain a pancreatogram advance a guide wire into the pancreatic duct through the papilla or a pancreatic oxygenostomy or what have you to allow for for subsequent ERCP afterwards. Again generally performed in benign disease with with normal anatomy. Success rate around 85 percent. My that's published literature. My experience is that this is not not that easy. I think this is a technically challenging procedure particularly do it as a rendezvous but any sort of pancreatic intervention is technically challenging when you're using an EUS a therapeutic EUS approach. The other thing I would submit is that any therapeutic EUS procedure as it relates to the pancreas is has a high a high morbidity potentially mortality risk to it more so than some of the other procedures you'll see tonight. So keep that in mind. Be very wary of intervening on the pancreas unless you really have to. As stated high adverse event rate pancreatitis around five percent but other things such as perforations bleed do occur as well. So when we think about this EUS guided rendezvous as a whole the advantages it permits conventional ERCP if that's desired. There's a the published rate there's a lower rate of bile leak or pancreas leak than transmural drainage that's in literature. I don't know if I totally believe that but that's what the literature would say. The disadvantages from my perspective is guidewire manipulation can be really difficult. If you use the extra hepatic biliary approach your needle often points towards the liver or the or the hilum and getting it to point towards the small bowel or the major papilla can be challenging. If you use the intra hepatic bile duct approach the wire tends to want to go in the right direction. However you have limited pushability of the wire because it's such a long distance from your puncture site to where you actually want to get to. When you think of the pancreatic approach it's mainly limited just by limited working space for guidewire manipulation within the pancreas duct. There's always a risk of wire shearing. I tend to use as I said a 0.025 inch long angled guidewire with a low risk of shearing but it does happen and is possible. The other disadvantages to this approach whether it be pancreas or biliary is that it requires a scope exchange and there's always a risk of twisting the guidewire or losing the guidewire or any of these things that can happen to your rendezvous wire that would make your procedure a failure. It's also dependent on duodenal anatomy. For example employing a biliary rendezvous from the left hepatic duct if the patient has a duodenal stricture doesn't really make sense because then getting your duodenoscope to reach the wire is really not feasible or maybe challenging at best. Just things to keep in mind. Now we'll turn to direct biliary drainage. We'll start with EUS guided choledochoduodenostomy. Choledochoduodenostomy is basically creation of a connection from the duodenal bulb to the extra hepatic bile duct most commonly for distal malignant biliary obstruction. This procedure is performed using direct drainage approach. It can be performed in various scope positions and it utilizes a tubular stent or aluminum opposing metal stent. It really just comes down to personal preference. The benefits for aluminum opposing metal stent is that it's streamlined. It's kind of a you know everything's housed during in that aluminum opposing stent whereas a fully covered tubular stent requires tract dilation maybe a cystotome or different things to gain access to the bile duct before you place the stent. Very high technical success rate. Adverse event rate around 50 percent with the expected potential adverse events of bile, cholangitis, perforation, and bleeding. This is kind of what this looks like in a couple different images. So this is a the standard scope position which leads to the challenges of the procedure. You're kind of working upside down and before the advent of the small caliber cystotome it could often be difficult in piercing the bile duct wall to get your accessories into the biliary tree. Afterwards essentially you're creating connection that will be solid. The duodenal wall and the bile duct will adhese to each other creating an anastomosis that can subsequently if you desire a revision from metal stent to multiple plastic stents there's no problem in doing that. As a kind of an alternate procedure and something I tend to prefer more than a colico-duodenostomy is hepatic gastrostomy. So creating a connection generally from the stomach to the left branch of the left hepatic duct either the segment two or segment three bile ducts. Again this is a direct drainage procedure. It can be used as palliation. It can also be utilized to convert a percutaneous tube to internal drainage. In rare circumstances generally surgically altered anatomy you can utilize this approach for stone removal or stricture therapy if the ampulla or distal bile duct is otherwise inaccessible. Again a reasonably high technical success rate, acceptable adverse event rate, and again you create by doing this we create a an anastomosis between the stomach and the left hepatic duct. So revising your stent in the future or moving the metal and going to only plastics. Generally plastic pigtails is totally fine. Patients do really well with that. Generally when I do this patients end up getting stent exchanges only every six months and I think they do quite well with that. So I think it's a really elegant procedure and has a lot of power in terms of how we can help patients. Here's another video. So here you'll see me targeting a branch of the left hepatic duct trying to not puncture anything that has flow in it. 19 gauge needle and you'll see here the puncture shortly. So we're in the bile duct start to inject contrast and then on fluoroscopy you'll see the cholangiogram which is obtained. I generally try to obtain a pretty full cholangiogram to kind of map out my plan. In this case it's a patient with normal anatomy could no longer access the bile duct from below. So guide wire is passed. In this case it's in the right hepatic duct which is fine. This is a balloon catheter now being advanced and then I typically will dilate the bile duct wall. I'll dilate the hepatic parenchyma and then dilate the gastric wall before I start placing stents. I tend to hold my dilations of the liver capsule and gastric wall for a little bit longer. Here you see a lot of pus draining after this procedure was performed. I also generally will place a double pigtail stent but what I was saying is when I dilate particularly the liver capsule and the gastric wall I hold the dilation for generally one to two minutes to make sure that my tubular stent makes it through. And what I do is I have my techs and nurses ready to go such that I don't deflate the balloon until the person standing there with the stent to minimize that bile leak that we were talking about. All right to kind of round out biliary drainage US guided cholecystoenterostomy or US guided gallbladder drainage. This can be performed from the gastric antrum or from the duodenum. I think the duodenum is a much better option. I think the times where I've used the gastric antrum tend to get a lot of food debris from the patient's eating that goes into the gallbladder and I think you also run the risk of recurrent cholecystitis much more than you do in the duodenum. Additionally, you know, for both procedures, if I do this and it's a patient with benign disease, I always revise it to a couple of pigtail stents about four weeks after. I'm not a big proponent of accessing, going into the gallbladder and removing stones. I think as long as bile is draining, patients are at low risk for getting recurrent symptoms. Here's a EUS guided gallbladder drainage. This is a big juicy gallbladder you'll see here full of a lot of ultra thick sludge. The lumen opposing metal stent catheter starts to burn. It's through the duodenal wall. Now it's through the gallbladder wall. I tend to push the catheter out as far as I can from a safety perspective. And then I deploy the first flange and pull back on that wall. And then I always have a preloaded guide wire and I use it basically as a safety wire such that if something goes sideways, that guide wire might be the only thing that saves me from a bad complication. And then here you can't even see the proximal flange very well because the stuff that's draining out was so thick and tenacious. This tends to be kind of the next procedure people progress to after kind of mastering lumen opposing metal stents for pancreatic fluid collections, because they're very similar in approach in most cases. A little bit trickier, a few more things to think about, but generally same idea. Again, in this procedure, high technical success, high clinical success, adverse events, 18%. But the big one we need to keep in mind is recurrent cholecystitis. The advantages of this procedure in terms of other procedures like a cholecystostomy tube or transpapillary gallbladder stents is that this allows us to place large diameter stents. If you desire to intervene on gallstones within the gallbladder, you can, they're accessible. I don't think it's necessary, but you can. But most importantly, it prevents the need for a percutaneous tube. This can also be utilized to internalize previously placed percutaneous tubes in select patients. The disadvantages, which I think are notable in this case, and there's certainly something that needs to be discussed with your, you know, in a multidisciplinary fashion is that this may preclude any laparoscopic surgery or maybe even liver transplant in select centers. It's going to make, at the very least, the operation much, much harder and probably would be an open cholecystectomy given that now you have an anastomosis from your gallbladder to the second duodenum or the duodenal bulb. And like I said, the risks of failure after puncture, in this case, if everything falls apart and you have a big hole in the gallbladder, the gallbladder is an exceptionally unforgiving organ. So it's going to be very difficult to salvage that endoscopically and could make a bit of a mess if surgery is needed. Just something to keep in mind. Salman, it looked like there were some questions that popped up. Is there anything that you wanted to discuss now before I went forward? Yes, absolutely. So one question is, if there is already a percutaneous drain for direct make, I think they're asking about hepatical gastrostomy, is it harder to do that procedure because the bindup is already decompressed? Yes and no. So it is decompressed, but if you are fortunate enough to have a talented interventional radiologist, what they can do is utilize their percutaneous drain, which at least at our center is more frequently on the right. They'll utilize their drain to basically help me create the connection. So they'll send a guide wire from right to left and get a guide wire in the left hepatic duct and then place a Fogarty balloon or an occlusion balloon over their guide wire and then inject contrast to distend out that branch of the left hepatic duct, which I can then see under EUS and target. So you're 100% right. The drain placement does make the ducts drain, that's what it's there for. But there is a pathway for which to utilize that drain to your advantage. And then for direct gallbladder drainage, how do you compare it to existed ducts tending via ERCP? How do you decide between the two? Yeah, that's a good question. A lot of it comes down to if we actually believe the patient's going to be a surgical candidate ever. And I would say that that requires a very kind of direct and honest conversation with your surgical colleagues. If it's a patient who just needs to kind of calm down and they're gonna go to the operating room in six months, then I think it's much more reasonable to pursue trans-papillary gallbladder drainage using pigtail stents. But listen, I mean, we've all seen the general surgeon who says, you know, yeah, we're gonna take this person's gallbladder out in six months and it's like an 80-year-old with Parkinson's and heart failure in a wheelchair. That patient's never getting their gallbladder out. And so I think that's where the discussion needs to be had about what really is the right thing. Because in my belief system, and I think Amritha's too, if a patient can't have a cholecystectomy, which is the gold standard for cholecystitis, the next best option for them in most cases is probably EUS-guided gallbladder drainage. Double pigtail stents may work and we use them frequently, but if you say what is the best possible option, that's kind of my belief. Does that change if the patient is a cirrhotic? Do you worry about collateral vessels in the way? Yeah, I mean, anything about a cirrhotic, I worry about, to be honest with you. Yeah, there's that much more you need to be having consideration. Does the patient have bad portal hypertension? Do they have pericholedocal varices? There's a lot of things that go into play. Platelet count, INR, those things maybe come into play a little bit more than in patients. Otherwise, it still can be used, but on a select patient basis would be my party line. Just to round out EUS-guided gallbladder drainage, don't forget that this can be a salvage procedure for patients who have malignant biliary obstruction, distally, when you don't have an option or not a good option for a hepatical gastrostomy or choledochoduodenostomy. If the gallbladder is distended, it would seem almost certain that the patient has a patent cystic duct in that setting. So draining the gallbladder, you're effectively able to use the cystic duct as your drainage conduit to drain the remainder of the liver through the gallbladder. There's several articles on this. Again, this isn't something that I would say we do frequently, but it certainly is a reasonable option. And it also is something that can keep patients from needing percutaneous drains. So a reasonable option to consider in select circumstances. All right, direct pancreatic drainage. As I said, messing with the pancreas, you have to be very careful. You have to realize what you're getting into. So in this situation, what we're talking about is one of two things, puncturing the pancreatic duct and getting a guide wire to go through the papilla or through an anastomosis. And instead of doing a rendezvous, you place a stent antigrade that's called pancreatic ring drainage or a direct pancreatic gastrostomy where you leave a stent that just connects the stomach to the pancreatic duct, because you're unable to get a wire or catheter or what have you across an obstruction, a stone, an anastomosis that's strictured, any number of things. Generally, this is done for palliation, though I'll show you a case later where it can be utilized in benign circumstances, can certainly be utilized for benign pancreatic duct strictures or bad stones, but typically this is a palliative thing. I think the most common scenario where we see it is post-whipple with a strictured pancreatic adrenostomy. And as I said, this allows you to deliver antigrade therapies, stricture therapy with balloon dilation or laser, stone removal using electrohydraulic lithotripsy, a lot of options this can open up. Very little literature on this, to be honest. Technical success, these are my numbers, I would say, or my guesstimates for people worldwide. Technical success, probably 75 to 80%. Clinical success is assuming technical success, probably 85 to 90%. High, high rate of adverse events. And like I said, the most morbid procedure we perform, in my opinion, I can think of a patient who I did a ring drainage on and it was like, it was a piece of artwork. It looked great. It took 30 minutes. It was no big deal. And then the next day she had a huge fluid collection. Two weeks after that, she was bleeding from the tract and ultimately did fine, but there's definitely no victory laps with any of these procedures. But in this one in particular, it's very morbid. So just something to keep in mind. So here's a case, puncturing pancreatic duct from kind of the pancreas body, immediately distal to the neck. Inject some contrast. You'll see a jet of contrast go through the pancreatic or jejunostomy right by that clip and go into the small bowel. There's the jet there. Ultimately, we were able to get a guide wire across. Here's a small caliber dilating balloon, either a four or six millimeter dilating balloon at the PJ. And then we subsequently leave a long, at least I do leave a long seven French double pigtail stent that goes from the stomach, traversing the pancreas and then into the downstream bowel. So this would be an example of pancreatic ring drainage. All right, now kind of starting to wrap up, we'll talk about luminal access procedures or procedures that can be used to permit ERCP. And there's kind of three in this group. There's EDGE, which is creation of a gastro gastrostomy in patients who've had Roux-en-Y gastric bypass, connecting the gastric pouch to the previously excluded stomach with subsequent passage of a duodenoscope through your luminoposing metal stent to allow conventional ERCP. And then the other one that we'll touch on is a US-guided gastroenterostomy, creating a connection from your stomach to either the distal duodenum or proximal jejunum most commonly to bypass duodenal stenosis from a pancreas cancer or gastric cancer. We won't talk too much about US-guided enteroenterostomy. This is a version of a gastroenterostomy except you're going small bowel to small bowel. And to be honest, this comes up very infrequently. I think I've maybe done five or six my whole career. It just doesn't come up all that often. So we're not gonna spend much time on it. All right, so for EUS-guided gastroenterostomy or EDGE procedure, this allows us options to perform ERCP or EUS in patients with Roux-en-Y gastric bypass anatomy given that issues with lap-assisted ERCP or long-limb ERCP using device-assisted enteroscopy each have their particular challenges. This can be performed as a single-stage procedure and when it's emergent, generally it's performed in two or three sessions with creation of the tract, followed by ERCP or ERCP and EUS, generally three to four weeks later. And then the final procedure is removal of the stent and closure of the gastroenterostomy fistula. The picture to the right is what we call the sand dollar sign. And that's because it's somewhat looks like a sand dollar under ultrasound. And what you're seeing there is the stomach. The part that you're seeing actually is the gastric antrum. You're seeing it kind of in a short axis view with your echo endoscope positioned either in the gastric pouch or the blind jejunal limb. And this oftentimes in patients who have a decompressed gastric remnant is the only thing you can find to help identify where the stomach is. So that's kind of what you're looking for in some of these cases to get started. Here we'll demonstrate an edge procedure. You'll see that kind of sand dollar appearance, puncture with a 19 gauge needle, injecting fluid, which is contrast methylene blue and saline. The other thing I would say, here you'll see the burn through. This is actually an older video on an older EUS system that I used. Deployment of the lumen opposing metal stent is the same. I deploy the distal flange, send a guide wire, and then deploy the proximal flange in the gastric pouch or blind jejunal limb. A couple of things with this. It's important to note that doing single stage procedures really should only be done in the setting of a gastrogastrostomy. If you go jejunal gastrostomy, there's a high risk of dislodging your stent during the second part of the procedure. So just something to keep in mind. These are technically difficult to do in one stage, but they are doable. Some people have demonstrated either clipping the stent in place or suturing the stent in place as a means to prevent disruption when you're passing the echo endoscope or ERCP scope through the stent. But a higher risk procedure, definitely to do it in one stage. Again, the biggest thing for this procedure, EUS guided gastroenterostomy. So we're seeing quite a bit of these. And as I mentioned, lumen opposing metal stent is working to gain an indication here in the United States for this procedure. The main, let me go back one slide here. Okay. The main advantage of this procedure is you prevent the patient from needing things like venting pegs or PEJ tubes or needing a surgical gastrojejunostomy if they have an obstructing cancer in the duodenal lumen or distal stomach. Very good data suggesting that there's a decreased re-intervention rate related to self-expandable metal stents, despite having similar technical success, clinical success and adverse events. I think it's ideal for patients with good life expectancy, but realizing that these are people who have a terminal illness. It does allow, you know, per oral nutrition as opposed to TPN. And it may allow access to the major papilla for ERCP in the setting of the need for recurrent stent exchanges, for example, in a pancreas head mass obstructing the bile duct. Very high technical success rate and clinical success rate, about a 10% re-intervention rate in the literature and about a 10% adverse event rate as well. These are high risk, high reward procedures. I can tell you that all of these stress me out. This stresses me out more than some of the other ones just because there's a lot of things that I think we don't know about it. I think there's still a lot of questions that we're answering in terms of adverse events and, you know, overall just how patients do clinically in the long run. We don't know for the patients who outlive their diagnosis and have these stents in place for a long period of time, we really don't know what that looks like. We don't know if the stent stays together, if it delaminates, if it erodes into, you know, the colon or if it erodes into blood vessels, there's a lot we don't know. And I think we'll hopefully be sorted out in the coming years. Here's a video demonstrating gastrointestinalostomy or using a nasobiliary tube to distend the small bowel to create an endosonographic and fluoroscopic target. And then you'll see the cautery being applied here shortly. All right, through the gastric wall, through the small bowel wall, and then the stent is deployed in kind of standard fashion. Again, anytime I use these stents, I like to have a little bit of a runway where I can push them out as far as I need to, just to give myself the ability to deploy that flange and pull back and secure everything. And then here you can, a view of looking through the gastrointestinalostomy and seeing small bowel mucosa. What I didn't show in that video, but the better or the other confirmatory sign is you see a large rush of your blue tinge fluid, which is just dilute contrast and methylene blue. All right, so just real quick to wrap up, a couple of kind of cases, a little bit out there. Thankfully, everything worked out with both of these patients, but quite high risk. This is a patient who had bad pancreatitis and had what we thought was a disconnection in the head of her pancreas. You can see there a missing section in the pancreatic head. I went and did an ERCP, and that's kind of the cutoff of the pancreatic duct. I put a stent in to prevent pancreatitis, subsequently looked at EUS options, thinking that I was going to have to do a pancreatic gastrostomy because she was a poor surgical candidate. So we puncture the pancreatic duct here at the neck, inject contrast, fills out the pancreatic duct. And then what you will see is it starts to fill a little jet of what I think is a fistula that heads down towards the bowel. You can see from that pancreatic duct stent that that's not the major papilla. What I think this is is a fistula that occurred naturally in the setting of her necrotizing pancreatitis. And I was always taught by my mentors that you have to use what nature gives you. So we actually used that fistula. We used a cystotome to gain additional deep access in the pancreatic duct, and then subsequently dilated the entire tract back and left her with a long double pigtail. She subsequently has come back and I've given her a double pigtail kind of in each direction, one through that old fistula's tract, and then one back towards the tail of the pancreas just to ensure that everything stays open. And she's done phenomenally for almost a year now with this situation. So again, not something that comes up a lot, but a good save for a patient who otherwise would have very poor options. All right, and then the final case is a EUS ERCP combo. What I can tell you about this particular patient, she had a total gastrectomy for gastric cancer and had Hypec for the treatment of her cancer afterwards. And when she was reconstructed, she had a very, very small, there was a very small amount of stomach left, like very little, a couple of centimeters maybe. And she had what amounted to nearly an esophagogygonostomy with the Roux-en-Y reconstruction. We were able to get to her bile duct with long-limb ERCP on one occasion for the placement of one single seven French stent, but that wasn't really feasible for her. She was from out of state, from quite far away and was looking for a more durable solution. So that's where we come in. Here, you'll see a really, really bad stricture going into her right hepatic duct and involving several secondary branches of the right hepatic duct. We dilated many of these branches open and then subsequently left it uncovered. This is a small caliber delivery system to go through a colonoscope. We left an uncovered metal stent just draining the right system. We don't even see the left system here whatsoever. The left was taking off in that stricture and not otherwise accessible in this route. So this is kind of her right, the treatment for her whole right system, I guess. The left system then was managed with hepatic gastrostomy. And the plan is to manage her left and right system separately if she ever needed subsequent intervention. So here you'll see, again, contrast injection. And here's the fluoroscopy. We're filling out what looks like a segment two bile duct with contrast heading down towards her right-sided stent. Ultimately, I was able to get a guide wire through to kind of anchor my position a bit more. That area was then dilated and then a 10 millimeter by eight centimeter fully covered stent was placed with a pigtail placed co-axially through the fully covered stent, which I'll show you here in a second. Here's the pigtail being formed. This patient actually has not needed any further biliary intervention. She has, I haven't even taken out, normally I would take out her metal stent and exchange it for a couple of pigtails in the left hepatic duct, but she hasn't needed anything. Her biliary chemistries have remained within normal limits. And here's how kind of how everything looked at the completion. So with that, I'll wrap things up from a therapeutic EUS perspective, things to continue to evolve rapidly for the benefit of the patient. I think mostly in my opinion, it's important to be aware that unconventional solutions may exist when kind of conventional things are unavailable. These ductal interventions are determined really on a patient by patient basis. There is no real cookie cutter approach. It's much more, it's very important to kind of be malleable and agile to adapt to kind of each patient because that's really what it requires. The other thing I would say is that before you embark on any sort of therapeutic EUS procedure, it's paramount to have high quality cross-sectional imaging to kind of prepare your procedure. Think about what your plan is going to be and also think about what your bailouts are if things are going to go sideways. I do think that we will see future devices develop in the future that will make these procedures easier, safer, and mitigate some of the challenges and risks that we currently have. So with that, I will wrap up this part. And if there's any questions, feel free. Otherwise we can move on directly to Amritha and take questions at the end. Thank you so much, Dr. Law, for that incredible talk. Your videos made them look really easy, but as somebody who's actively trying to learn some of them, it can be very stressful for working these procedures. Yeah, Salman, I would tell you that despite how you see those or your mentors make these videos look, Amritha can attest to this, that they're very stressful. They are mentally stressful, they are taxing to keep you up at night. So it's a great thing to do, but just realize what you're getting into. Absolutely. That's what makes this feel so amazing as well, all that we can achieve for our patients. With that, I will love to introduce Dr. Amritha Sethi, who's going to be our second speaker for today. She's a professor of medicine and director of intervention endoscopy at Columbia Presbyterian Hospital in New York. Hand it over to Dr. Sethi. Thanks, Salman. Appreciate that, Ryan. Great talk as always. And yeah, those procedures definitely keep you up at night as do some of what I'm about to talk about. And Ryan and I had a little conversation before this when we were both involved in these procedures respectively. And sometimes you just got to wonder why we're doing it, but because we love it, so. So I'm going to keep it pretty basic and introductory, lots of videos. We'll show a couple, two kind of fun cases at the end, and then happy to take any questions. So I'm going to be talking about submucosal endoscopy and third space endoscopy. So important to ask, what does that mean? What are we doing here? Basically, we're working within the submucosal layer, which is really a potential space, but then it can be expanded, it can be dissected. We can remove from within it, or we can access other areas, whether it's the muscle or even extra luminal. And it does require good dissection techniques as well as closure methods, but really understanding the anatomy, understanding the planes, and excellent knowledge of all of the tools and accessories that we're going to use. And the main procedures we talk about in this space are ESD, the various different poem procedures, that we'll look at something called like a STIR procedure, for example, and then even full thickness. So to start off, we have the ESD itself, which is basically an organ sparing technique that allows you to perform a curative resection, particularly early mucosal neoplasms, although we're kind of pushing that limit a little bit throughout the GI tract. And it basically serves the foundation for all of third space endoscopy in terms of technique. And these just show some different types of resection, which we'll go over. But ultimately, what's your goal here? Again, we are talking about surgical oncology. So what we wanna do is respect those principles, which do include having an on-block resection that allows for proper pathologic, proper assessment by our pathologists to really comment on whether this is an RO resection, whether we have a lymphovascular invasion, and most importantly, to really understand whether there is a need for further lymph node dissection. That is, what is the risk of lympho, of metastatic disease through the lymph nodes? And can we ask ourselves, can we help patients avoid more invasive surgeries, such as esophagectomies or colectomies with the corresponding lymph node dissection? Obviously, we wanna minimize adverse events and we wanna minimize recurrence, but ultimately we wanna allow for preserved organ function. And so just, if you haven't seen it, these are kind of the different layers that we're talking about when we work in the submucosa. It's down here between the muscularis mucosa and the muscularis propria. Even the layers within the submucosa are important with respect to depth of invasion. In general, when we are dissecting in the submucosa, we wanna get down to this third layer here, where the lymphovascular network is contained and allow for that information to be given to us with regards to staging. So what's really important about, if you're gonna embark on ESD or a third space procedure, such as FOM, is to really think about the indications and do a lot of pre-diagnostic work to make sure that we're doing the right procedures and the right patients. We need to know what is the risk of malignancy if a patient has a lesion that is T2, for example, or even T1B in the esophagus, where there's increased risk of lymphovascular invasion, that even performing the resection, even if it's an RO resection, isn't very helpful if that patient, by surgical oncology principles, needs a lymph node dissection. So one of the things that's important in ESD is really using surrogate markers to help determine what that risk of invasion is. And for that, we really rely on an optical diagnosis that we make by looking at different classification systems. These two here are two of the most common that you'll see, particularly in the US, but the PARIS classification system and the J-NET or NICE classification system that really helps us look at morphology of a lesion as well as the vascular pattern and surface pattern and whether those are preserved. And it's not for this talk, but that can help determine what is the risk of invasion and whether a lesion should be, in fact, approached with ESD. And there are other kinds of imaging too, such as chromoendoscopy, whether it's by looking at filters on your scopes or applying Lugol's or methylene blue or other chromoendoscopy agents, and then even magnification endoscopy or confocal laser endoscopy. And then we also wanna pay attention to the size. Larger lesions do carry increased risk, particularly in colorectal lesions over four centimeters of submucosal invasion, as well as their circumference and how, again, we want it as much as possible to perform on block so that there's no question of being able to read our margin. So sometimes we have to even think about performing entire circumferential ESDs. This is the other classification system that you really should get to know and should be part of all reporting is the LST or lateral splotting tumors. And whether they're granular or non-granular, these also are very important in predicting risk and in terms of indications for performing ESD. And again, it's not really for this talk, but become very familiar with this if you're going to think about entering ESD into your practice. So what are the actual indications for the esophagus? We really look at sort of the Japanese indications, which don't apply as much to the US with a little bit less Barrett's, but the ESGE has also come out with a good set of indications. Again, the flow of the algorithms for these guidelines, which are an excellent read, do first indicate all the diagnostics, really looking at all of those more characterizations of systems that I mentioned to you also include things like PET scans or CTs if we're concerned for deeper invasion. But for squamous cell CA, this actually is a very amenable disease to ESD. And so there's a little bit more leniency with regards to how deep these lesions might be or how advanced they might be and whether we can approach them with ESD. So T1A lesions, even those that are involving a significant amount of the circumference, it's almost three quarters, or if you have skip lesions, you can perform circumferential ESD and even going deeper to less than 200 micrometers of submucosal invasion, which in adenose CA would be considered perhaps a T1B, but in squamous cell, these are curative through ESD. And then for Barrett's high-grade and intramucosal, or basically in the spectrum of adenose CA, we're talking about lesions that cannot be performed on block by EMR that have more advanced pathology, such as high-grade dysplasia. This is definitely an area of debate and it's part of every single course ever is EMR versus ESD. If I think it starts to depend on what you do in general in your practice, I'm a big believer in on-block pathology, you know, resection. And so anything that can't be taken in one piece, I would remove by ESD, particularly if there's high-grade dysplasia or more. PARIS 1S or 2C, if there's poor lifting and any other risk factors for submucosal invasion. One of the most common indications that I get is patients who've been treated multiple times by RFA, by EMR, by cryo, and they still have persistent dysplasia or they have recurrent dysplasia or intramucosal, and those patients get sent for ESD and those can be extremely difficult, but ESD does tend to be the only way to really be able to remove those lesions. For gastric lesions, this has really taken over as the method of resection. You know, EMR has a lot of limitations, especially with band when you're dealing with the thick mucosa, particularly with chronic gastritis, or even the very thin mucosa in patients with atrophic gastritis, and performing ESD tends to be much safer. So it's, again, very forgiving in terms of the type of lesions that we take out. They can be really any size, and I'm sure Ryan also has done himself or colleagues where we're taking out almost half of the lining of the stomach, and the most common and the best suited for this are those that are well-differentiated, not ulcerated. If they are undifferentiated lesions, then they really do have to be smaller in size because the larger they are, the increased risk for submucosal invasion and lymphovascular invasion, and non-ulcerated. And you can see here the kind of contraindications, and it's very important to properly assess these, make sure that you're not dealing just with biopsy scar tissue, and do a proper EUS and staging for them, and get them to surgery if they need to. And then the most common that we probably see here in the U.S. is colorectal ESD. Again, just paying attention to, these are from the ESGE guidelines, which are really quite good guidelines, I would say. Again, the Japanese guidelines are excellent, but they don't really apply so much to our practices in the U.S. So this is a good set to kind of go off of, and it's also mirrored by American or U.S. guidelines, as, for example, in the AAGA practice guidelines. But again, we're looking at size, classification, assessment of vascular and surface patterns. And then those that are most commonly indicated for ESD would be the JNet2B patterns, where this suggests high-grade dysplasia or intramucosal cancer, or even now SM1 lesions. If in the colon, you can perform EMR. Again, this is a big topic of debate, but if you're interested in on-block resection, or you've had patients who have had prior hot biopsies or partial resections, scar tissue, or tattoo underneath the lesion, these are good patients to undergo, consider performing ESD. And here you can see some of the classifications that are particularly indicated, like non-granular, because non-granular does carry increased risk of invasion, or mixed type with large nodules, where you definitely wanna make sure that you're getting proper margin assessment, particularly under the nodules, given their increased risk for semicosal invasion. So the next thing to think about after finding a lesion that is appropriate for ESD is what are the tools that you're gonna need and making sure that you have them all available and that you have competency in how to use these, not only yourself, but most importantly, the team that you're gonna work with, your nursing team, your tech team, that your anesthesiologists are familiar with the procedures that you're gonna do, and not only to perform the actual dissection itself, but also to deal with complications. So, of course, we're talking about expanding the submucosal space, so we wanna make sure we have good lifting agents from anything from homegrown Hexand with methylene blue, and now we have pre-made solutions as well by all of the companies that are available, some with dye, some without. Some people will add epinephrine to their solutions, depending on where the resection is being performed and personal preference. And then the most important are the knives themselves. There are many, many knives available. In general, category-wise, they can be classified into needle-type knives, scissor-type knives, hook knives. There are those knives that can inject the solution and cut at the same time, and there are those that just only have the function of resection. The insulated tip knives allow one to work in difficult planes to help avoid injury to underlying muscle. And then there are the hemostasis devices like coagulation graspers and some others that we'll talk about shortly. The excellent knowledge of your electrosurgical unit is absolutely imperative. There are many different settings. Oftentimes, it's endoscopy preference, but different settings apply to different types of tissues. And this is probably the first lesson that you should have if you're gonna enter not only this space, but even just resection in general. What does it mean to perform cutting current, coagulation current? What's safest in which situation and most efficient? And then something that has really gained a lot of traction in ESD lately and really been something that we've spent a lot of time and energy on are traction devices and traction methods. And that actually, I think, really can make a very big difference and also guides the techniques that we are gonna use. And then with that, I'll go into those techniques. And I would say that the techniques actually do have to do with thinking about what kind of traction or method of really allowing for exposure of the planes, the right planes of the tissue that will make things most safe and most efficient. And so the conventional technique is first marking out the entire lesion, injecting all the way around the periphery, performing a full circumferential incision after performing the injection so that you are releasing all of the mucosa from the surrounding mucosa and that will allow for you to just have exposure to all of the submucosa and final dissection. And then you have the actual dissection itself in which you're gonna encounter vessels. Again, this is something you wanna do in that lower third space of the submucosa, not only for the margins, but also to minimize the sort of vessels that you're gonna reach and instead of encountering clusters of small caliber vessels, really get to the roots of larger vessels. And then of course you have to perform hemostasis if bleeding does occur or perform prophylactic. Closure becomes very variable depending on location and ultimately also specimen presentation. So that's the conventional technique. And then we sort of realized that, well, in the conventional technique, the traction device was the cap that is another really important part of our equipment. But there are other methods to do this naturally. And one of them is actually to allow the lesion itself to serve as a traction, a roof, if you will, and create some tension on the submucosal space. So for example, the pocket technique is really kind of just making an initial incision here and kind of entering into this pocket, dissecting through and allowing the, as you lift, allowing the mucosa to pull up on the submucosa and really expose those fibers. And you do one side, you do the other side, ultimately you also do the distal or in the colon, this would be the oral end and then finish with the lateral margins. And with this technique, you can actually take out very, very large lesions. This one is 12 centimeters from a publication and really circumferential, almost circumferential lesions in the colon, which is very difficult to do, especially when you're going over multiple folds and you have to make sure you avoid the muscles. So this is a really good technique. And in fact, the ESGE recommends this technique for colonic ESD when feasible to make it safer. And then there's the tunneling technique, which is very, very similar. The tunneling technique, you're still also gonna make this sort of more proximal or anal incision, get inside here, we're inside the tunnel. So mucosa is on the top muscle, colonic wall is on the bottom. You go all the way through until you actually reach the distal or the oral incision and kind of get your scope through and be able to be sure that you've made it all the way underneath the lesion. You continue to dissect until it's just the lateral margins that are left over. And then it just becomes a question of cutting the lateral margins. As I mentioned, sometimes you really need to take out the entire circumference. And this is particularly the case in the esophagus where you're dealing with large segments of Barrett's or high-grade dysplasia or early cancers. And in these situations, you don't want to just purposefully leave in lesions or make them smaller in order to avoid circumferential ESD, although it is now something that is being practiced a little bit to decrease stricture rate, which is very, very high when you perform circumferential ESD, it's definitely a big risk. What's made circumferential ESD a lot easier and actually quite fast now is performing tunneling in multiple locations. So maybe two or three tunnels, and that way you're really not fighting the lesion as you go down and you're maintaining traction throughout. And anybody who performs POEM actually finds that quite easy. So this has turned this kind of a procedure into something that's done much more commonly if you're performing esophageal ESD. As I said, traction is extremely important. There are devices that are now manufactured, such as the Prodigy. There are home-grown devices, such as the line-and-clip or the loop-and-clip, ones that aren't necessarily available in the U.S. as well. And traction is so important that, again, this is recommended to be used for all colorectal ESDs. This is a case of a sort of home device made at home. It's a loop made out of dental floss. So in this case, this was a really difficult-to-approach lesion because of a lot of looping and tortuosity of the colon. And so we really couldn't get to the right angles and get my knife in the right plane. So here you see a small loop made out of dental floss attached to a clip, which we then deploy onto the lesion and then attach the other side of the clip onto the opposite wall. And you can see how it really exposes those fibers. And then you can switch your knife, for example, to this insulated-tip knife, and you really use it as a hook. The other thing that's important about being able to have exposed planes is to be able to deal with things like bleeding. If you have the tissue folded over on itself, you're really not going to be able to see where that's coming from. So again, multiple different ways to do traction. But it is important to understand how to do it, incorporate it, make sure it's ready. This is a great thing to ask fellows to have prepared or prepare for you during your procedures. 3DSD is exactly that. It's performing an initial circumferential incision. This is particularly useful if you have a lesion that could otherwise, you know, the margins aren't as important to get deep down into, but there's scar tissue because of biopsies or a partial resection attempt in the past, or even tattoo. So making circumferential incision, dissecting a bit out so you can really establish that plane and then seeding the snare in the submucosal plane and then ultimately performing an EMR. And then full thickness resection with the device is included when we talk about advanced resection techniques in third space endoscopy because of the fact that it is really a full thickness. But here we are finding a scarred lesion, or Dr. Siddiqui is finding a scarred lesion. The lesion is marked out and then this device, which is basically a sleeve that fits over the scope and contains a snare inside it, is attached to the Ovesco clip. The Ovesco clip gets deployed after pulling the lesion into the cap and then the snare resects the lesion over that's sitting on top of the clip. So this is called a close and then resect full thickness procedure. If you were to perform an ESD and go fully through the wall and then close it, it is called a resect and then close technique procedure, which is definitely something that sometimes does need to be done. So that's ESD. In terms of the third space procedures, the one that we know most commonly as the esophageal poem is a very standard technique that's been taught over and over and over. That is to create a mucosotomy tunnel one's way down across the GE junction and then perform. In doing so, you're exposing the muscle fibers because you're cleaning off the submucosal fibers over them. And then you perform the myotomy, so actually cutting the muscle and then ultimately closing that mucosotomy site to prevent adverse events. This has now been indicated for all subtypes of achalasia, for EGJ outflow obstruction, for complications secondary to things like sleeve gastrectomies and strictures, and even to create new tunnels if in the case of strictures. And really throughout the entire GI tract now, we've got procedures that use this particular technique of exposing the muscle and then allowing us to perform that myotomy. So anything up from the cricopharyngeus with the cricopharyngeal bar to zankers, to even things like DES or diffuse esophageal spasm, which previously did not have a surgical method of treatment, strictures like I mentioned, epiphronic diverticulums, of course, achalasia. And then we'll talk about gastroparesis and GPOEMs and now even for Hirschsprung's disease per rectal endoscopic myotomies can be performed, hence the alphabet soup of POEM procedures. So this is a classic sort of esophageal POEM. We go about, traditionally, we were going approximately eight centimeters above the LES. Now some of us are performing shorter myotomies, but here's the dissection. And then here is the actual myotomy. It's a little bit sped up, as Ryan said. These are very, very edited videos to get in time, but ultimately you see here the full myotomy and then the last step is closure, which can be done with clips or suturing. Again, your choice of what you want to do and sometimes depends on the state of the mucosa. This is a zankers diverticulum. Same concept here. We're performing a mucosotomy right on the edge and then dissecting on either side of the septum, exposing the muscular septum, and then going ahead and cutting all the way through. So traditionally you would have just cut the entire septum, including the mucosa. The disadvantage to that was that you had to leave just a little bit in order to not risk perforation and mediastinitis, but here we can not only cut the entire septum, but you can even perform a little bit of an esophageal myotomy and then ultimately just close that and this has, as a technique, excellent results and very good clinical success rates as well. The G-POM, the gastric POM procedure, is similar to the esophagus, but here you're really looking for this endpoint of the pylorus and it's a much shorter tunnel and it's a much shorter myotomy. In this case, I tend to perform what's called a double myotomy. So at the seven o'clock and at the five o'clock position and you're taking it all the way down to the serosa. Here in this situation, you'd want to do a little bit less bolus thickness. In the esophagus, some people will intentionally do that, some people will inadvertently do that. It really doesn't matter because ultimately you're closing everything up, but here in the stomach, you want to be a little bit more careful about that. You have to be very careful about the duodenal mucosa that you see kind of rising up behind that because duodenal mucosal defects can lead to significant problems. And in some cases I'll even take a snare and snare off that muscle that's in between these two myotomies just to help kind of decrease the rate of closing up again. So like this, just take a snare and then take off a small piece of tissue. And then ultimately, again, like the esophageal poem, the most critical step is really the closure. I tend to always do this with suturing because of the motility of the stomach, because of the thick mucosa of the stomach. This way I can really ensure a very robust closure, but really any type of closure is fine. And the STIR procedure is basically using the poem technique, but not necessarily for myotomy, but really for access to subepithelial lesions and allowing resection of these without and through the tunnel without having to really expose peritoneum or the mediastinum to an open ESD technique. And so here you see we dissect in the submucosal layer until we reach the subepithelial lesion. In most cases it's a leiomyoma or a gist. And you're here just dissecting the submucosa off of the capsule, which is very, very clear. This is, in these kind of procedures, hook knives can be very useful with insulated tips so you don't really damage the mucosa. And then the key is getting this out. So in most cases, what you want to do is remove it from the initial mucosotomy. In this particular case, this was probably one of my first STIRs many, many years ago, there was an inadvertent mucosal defect in the stomach, but we decided to just open it a little and actually use it as an exit point for this lesion, which I would have had to really expand the tunnel in the esophagus in order to get it out fully. So we just pushed it out into the stomach and then we closed both the gastric mucosal defect as well as the esophageal defect with suturing to then prevent any infection. So again, the techniques themselves are important, but so are managing the complications. And in some cases, not necessarily complications, but consequences like full thickness resection and being able to suture completely. So for coagulation, there are multiple things to do, but really good knowledge of coag graspers is important. This was a GE junction lesion that was resected. You can obviously see this taunting us, but we're going to use these coag graspers, grasping them, understanding the pottery settings, and then this can really help quickly take care of hemostasis. There are multiple other ways to do this now, whether clipping at the end, there's multiple powders, gels available that can be used either during the procedure or after the procedure. Again, just making sure that you know how to use the device is really critical. And I would say, again, as fellows entering this space, that these can be the most important roles that you may have. The greatest chance to make good impressions is when you know what you're doing with that and you're there and ready if anything is needed. Similarly, with closure, whether for perforations or whether for full thickness, there's multiple different types of through the scope clips, over the scope clips, and then of course, the most robust are the suturing devices, whether it's overstitch or X-TAC to allow us to really close the defects. So I'd say the take-home points for ESD in third space are really consider the indications, if it's oncologic or if it's access, consider, you know, if you need to, the orientation, the margins, the histology. I think participation in the field, you have to be really competent in the diagnostics first, as well as the techniques, the complication management, really know your equipment and really know how to work with a team. Participating in multidisciplinary teams is optimal. And once you know the fundamentals, you can expand the applications of skills. I know we're kind of running out of time, but I just wanted to show sort of extreme case even though this was many, many years ago, a little ahead of its time, but I just wanted to showcase some, you know, of our fellow work too, in terms of putting this video GIE together. So this was a gist in the stomach that had a large ulceration. And so her symptoms were actually anemia. So normally we would want to do a stir procedure, but because of the ulceration, you know, there's no way to keep the mucosa intact and create that tunnel. So what we did instead was really dissect all the way down to the lesion. And one of the issues became on being able to really expose the planes and realizing that it was coming from the muscle layer. And so here we were using different types of knives, but you can see here it's coming almost from below the muscle. So one of the important things that we decided to do was after dealing with things like bleeding, I'm just going to speed through this a little bit, was to use traction. So the first traction we use with the clip in line, when we attached to the roof of the lesion. So we left the mucosa on top of the lesion to sort of serve as an anchor to be able to do this. And then when you pull on that, you can see how it really pulls up, really exposes the planes. We lost that line. So then we switched over to a suture itself. In this case, the attachment was on the gastric wall first, and then through the mucosa that we kept on the lesion itself, pulled, and again, we got really nice exposure like this. And ultimately what this problem was, was a subserosal dissection, which is something that's being practiced now, even intramuscular dissection is being practiced. And then ultimately we close this up with sutures. The other video case that I was going to show you is a difficult poem. So poem technique itself, like I said, there's four main steps. And if things go well, it goes well, but what you have to be prepared for is these dilated esophagus, chronic esophagitis, all of the vessels you're going to reach inside. So this is a patient with a sigmoid esophagus. In these cases, it can be very difficult to maintain orientation. There can be a lot of scar tissue and fibrosis. You see, we made a very wide tunnel because of the sigmoid nature to help maintain orientation. And then I'm performing a retrograde myotomy here, cutting, you see the circular muscle on top and you see the longitudinal muscle underneath, and then hit a bleeder. Now typically if we see a vessel in front of us, we can prophylactically take it with coagulation graspers or low forced settings. But here in this case, we really couldn't visualize, we really couldn't control it with the typical techniques. So ultimately, after sweating out a little bit, and removing a lot of this clot with a Rothnet, we ultimately placed a CRE balloon and performed balloon tamponade within the tunnel in order to help slow the bleeding. This allowed us to visualize a little bit more. Sometimes you have to actually go and cut some of the muscle in order to expose the vessels and control the bleeding, and then ultimately finish the exam. So these situations do require, again, understanding the anatomy, understanding how to use different devices. In this case, we left a clip in there in case the patient bled again and IR needed some help to localize. And this is finally just closing the mucosotomy at the end of the procedure. So that's about it. Thank you, Dr. Setti, for the incredible talk. There is one question from audience. Do you prefer an anterior or posterior approach for the colon? I like posterior when I can. Sometimes, though, you have to if it's a redo colon, for example, or in some cases where it's really very sigmoid and the scope curls on itself or retroflexes almost and you really can't get into the tunnel and approach it sometimes. Or if the mucosa is really bad condition and the underlying submucosa is very fibrotic, sometimes you have to abandon the tunnels you create and start over somewhere else. For fellows who are interested in third space endoscopy in this day and age, how do you suggest going about learning third space procedures if they don't have access to it at their own institution or even if they do, what's the best way to go about it? Yeah, that's a great question. So there are fantastic courses that are available. The ASGE has traditionally had ESD courses. There was a foam course. I believe there will be opportunities for ESD courses in the future. There's also institutions that have courses and companies that also sponsor it. If you have an opportunity to go spend time with someone, that's wonderful. But I think not so practical for many of us. And then the video libraries that are available on multiple different platforms are excellent and oftentimes very educational. And they're made in such a way as to instruct in different scenarios. Attending live courses, whether in person or virtually, are really fantastic. You can get a sense of different ways to do different things. I think as a fellow, if you're interested in this, is really, again, use the opportunities you do have at your institution to know the devices, know the indications, practice every time you see a polyp. Is this a polyp that I could do an ESD on? Just so that you get all of that behind you. Scope control is absolutely critical. And that's something you can definitely learn in your general GI fellowship or as an intervention, you know, depending on where with anyone, because we all really that's that's absolutely fundamental to any of our practices, but especially for resection and even for third space. I mean, even for interventional US, I would say is really understanding scope control. And again, how do you use the devices? Be the one who they call into the room when something happens. And, you know, there's something technical about using the clip or using the system that you're the one who knows how to do it. And I think that's one way I would start. I don't know if Ryan has any thoughts on that, too, for therapeutic US. Yeah, I mean, I think that for anybody who's doing an advanced fellowship and is going to do a lot of therapeutic endoscopy, you have to understand scope mechanics. You have to understand how to how micro movements can make macro changes. And then the other thing is, you know, always working close. So, you know, I was telling one of our trainees today, there's nothing you're going to do therapeutically, even if it's simply placing a hemostatic clip that you want to be far away. So you have to be comfortable working really close. Obviously, poem, everything's right in front of you. Therapeutic US, everything's right in front of you. More times than not, there's not even a role for your endoscopic view and therapeutic US or at least not a major role. So I agree, you know, whatever you can whatever you can do to enhance your skills, your knowledge, your exposure to different things you should you should you should do. Awesome. Great. Thank you so much for the incredible talks again. I think we are reaching the end of our time. Any last words? Thank you so much. Yeah, thank you for the invitation. We appreciate the time. Oh, you're welcome. And thank you both for to both of our content experts and to our fellow moderator for tonight's amazing presentation. Before we close out, I want to let the audience know to check out the upcoming ASGE educational events and to register. Visit the ASGE website for the complete lineup of 2025 ASGE events. Our next Endo Hangout session will be Endoscopy in Pregnancy, and that'll take place on Thursday, April 17th from 7 to 8 30 p.m. Central Time. And registration is open. At the conclusion of this webinar, you will receive a short survey and we would appreciate your feedback. Your experience with these learning events is important to ASGE and we want to make sure we offer interactive sessions that best fit your educational needs. As a final reminder, ASGE trainee membership for fellows is only twenty five dollars per year. If you haven't joined yet, please contact our membership team or go to our website to sign up. In closing, thank you again to our presenters for this excellent webinar and thank you to our audience for making this session interactive. We hope this information has been useful to you. And with that, I will conclude our presentation. Please have a wonderful night.

Interventional EUS

Third Space Endoscopy

Endoscopic Ultrasound

Therapeutic EUS

Pancreatic Drainage

Biliary Drainage

Endoscopic Submucosal Dissection

Per-Oral Endoscopic Myotomy

GI Fellows

Endoscopic Techniques

Patient Anatomy

Multidisciplinary Collaboration

Advanced Endoscopic Procedures