Now, we will move on to our next talk, which will focus more on therapy. And we leave a lot of therapy questions towards the end, specifically on PPI therapy and medical therapy. But here's Ken Chang from UCI Irvine talking about minimally invasive endoscopic and surgical treatments for gastroesophageal reflux disease. Welcome Ken. Hi, I'd like to thank Prateek and Bonnie and the organizing committee for allowing me to join my prestigious colleagues on this virtual platform. My topic is minimally invasive endoscopic and surgical treatment of GERD. These are my disclosures. The key principles that I'd like to review today in the next 15 minutes is that there are many GERD patients who are refractory to PPI, who are appropriate candidates for but are not receiving antireflux surgery or procedures, and that the gastroenterologist and the surgeon need to work together as a team as there are many good antireflux options. The personalized approach to the GERD patient includes a thorough understanding of the anatomic alterations, and we'll go over this in great detail, which then informs the best treatment strategy. This paper in 2014 showed that the elective antireflux surgery in the US from 2005 to 2010 was essentially flat, roughly around 20,000 total procedures per year. A more recent paper in Gastroenterology 2020 surveyed over 71,000 people, and these numbers are quite indicative. 40% of US adults have GERD symptoms, so that represents roughly 80 million people. 35% of patients with GERD symptoms are on medications, that represents 28 million people. 55% of them are on PPI, or 15.4 million. The rest are on H2 blockers or antacids. 68% of the PPI users take it daily, so that represents 10.5 million people. And 54% of those daily users consider their symptoms refractory to PPI in that they have persistent troublesome symptoms greater than 2 days out of the week, and that represents a PPI refractory population of 5.6 million. Now if we go back and consider that approximately 20,000 antireflux procedures are done per year, that only represents less than 0.4% of those who may benefit from an antireflux procedure actually receiving it. This is an interesting trend comparing bariatric surgery versus antireflux surgery from 1990 to 2002, showing that antireflux surgery has remained pretty flat, while the bariatric surgery has tremendously increased. And that has to do with the changes in the obesity conversation moving the pendulum forward. Initially, there was a more internal competition, which surgical procedure is better, and the analogy to that is merely moving the same furniture around the room, whereas this conversation evolved to, well, how do we provide more effective therapy to more patients? And the analogy to that is bringing more furniture into the house, rather than just rearranging the furniture. And if we look at the GERD conversation, we need to move in the same direction, and as we look at the GERD conversation, we should likewise move the pendulum forward instead of spending our energy trying to pit one surgical procedure against the other, merely moving the same furniture around the room. We need to ask the broader question of how do we provide more effective therapy to more patients suffering from GERD, and that's where gastroenterologists and surgeons need to work together. Now moving on to anatomy, when I talk to patients, I explain to them that there are two important valves that function as antireflux barriers. There's the lower esophageal sphincter, which we are very familiar with, and then there's the diaphragm crura, which we as gastroenterologists focus less of our attention on. So in anatomy lesson number one, the crura is crucial as an antireflux barrier, even without the presence of a hiatal hernia, and there have been recent elegant studies looking at the morphology and function of the right cruce, which acts as a sling or a noose around the G-junction, and here you can see in the red, the right cruce that captures the G-junction, and when it contracts, it pulls this angle posterior inferiorly and to the right. And here we can see in green, the right cruce tugging on the G-junction, creating this almost right angle, which acts as an antireflux barrier. So the cruce is not just a passive barrier to gastric herniation, but it's actually quite dynamic and works in concert with the lower esophageal sphincter. And these imaging studies further bring home the point that the right cruce acts like a sling on the G-junction. This is an x-ray of the barostat balloon, it's radiopaque, and it's placed across the G-junction in a normal subject, and that almost right angle turn and pinch is caused by the right cruce, again, acting as a sling or noose at the G-junction. In a GERD patient without a hiatal hernia, we see that that angulation is no longer as acute and is more obtuse or relaxed, and this patient does not have a hiatal hernia, but likely has a sliding hernia situation because of the open diaphragmatic hiatus. And in the third image, we see that there is a hiatal hernia present and the angle is even more straightened, and that's because of the very open hiatus and the sliding hernia becomes more obvious. And what is underappreciated is this scenario, where there's no obvious hiatal hernia, but because of the open hiatus, this patient actually needs a crural repair, and this is something that has been underappreciated. So our goal during endoscopy is not only to look at the integrity of the lower esophageal sphincter, but also to assess the integrity of the crura. Well, how is this done? During endoscopy, this is the typical straight view, looking at the G-junction, and of course the retroflex view is very important to assess the integrity of the hiatus, and based on initial retroflex view, it looks fairly intact, one would call this maybe a hill one, and then on further insufflation, there may be some laxity, but if we just stop at this point, we may underestimate the openness of the patient's hiatus. However, on further insufflation, and moving the scope into the duodenum and back, you come back and reassess the G-junction, and you can see here that the diaphragmatic impression is now down here, and some of the gash of folds are above the diaphragmatic impression. And if you go back again on the same patient, same session, and do a retroflex view, you get a very different image, and this is the crura, and this is the hiatus. And if I were to take the patient immediately to surgery, this is that same patient, and on laparoscopic view, this is the right cruce, this is the right bundle, this is the left bundle, and this is the hiatus. And you can see here that the hiatus is quite open, and if I were to draw the impression of the hiatus on the retroflex view, it would be there, and that corresponds to what we're seeing laparoscopically. So it is important for us to assess, albeit imperfectly, the intactness of the crura as part of the GERD workup, because this patient needs a crural repair, and not just a repair of the flap valve. So anatomy lesson number two is that the lower esophageal sphincter is actually a bit of a misnomer. It should actually be called the EGJ sphincter, in that it includes the gastric sling fibers, which then make up the flap valve. Here you can see on the diagram on the left, the distal esophageal circular muscle is actually continuous with the sling fibers of the stomach. When this muscle contracts, it's not perfectly circular in contraction, because there is an attachment of the muscle and they crisscross here on the greater curve angle. So when the contraction happens, it actually acts to bring this flap valve from the greater curve to close towards the lesser curve in that direction. To illustrate this point, we can look on the right, and this is a typical retroflex view of the G-junction, and here you can see the gastric sling fibers creating this flap valve around the G-junction, and if I were to superimpose the muscles of the sling fibers, it would look like this. And again, the direction of the flap valve is from the greater curve side to the lesser curve side. Now I can reorient this by flipping the image so it looks very much like the picture on the left. So I just rotate that around, and now you can see that the sling fibers, oriented in the same direction, is creating a noose around the scope on the greater curve side, and here are the fibers, and the motion of the flap valve to close the flap valve is moving from the greater curve towards the backstop, which is that lesser curve, and that's shown here. So that's the normal anatomic function of the flap valve. Here for example is a patient whose flap valve is fairly loose, and you can see the sling fibers superimposed on the image, and this angle of his or cardiac notch is not so steep, but if we were to repair this, say we were to do a TIF procedure, which creates an elongation and augmentation of the flap valve, it would look like this. So you can see here that that cardiac notch angle of his is now much steeper as the valve is lengthened and narrowed and restores the function of the flap valve from the greater curve towards the lesser curve. So the sling fibers of flap valve can be augmented by various procedures, including Nissen, partial fundoplication, magnetic augmentation or links, but in addition, the gastro-gastric plication, whether it's done by the ELF procedure, TIF1 procedure, TIF2 procedure, the MACE procedures, which is mucosal ablation and suturing at the EG junction, or the RAP procedure, which is resection and plication, they all function to augment the flap valve, but merely as a gastro-gastric plication, whereas some of these other procedures, including the TIF2.0, actually restores the entire LES construct. Other procedures may function by decreasing the compliance of the sling fibers, making them less apt to stretch any face and trigger a reflux episode, and that is the possible mechanism for the stretter procedure or the anti-reflux mucosectomy procedure or ARMS. But for me, it was really the TIF procedure that helped bring to light the importance of the flap valve. This is the transaural incisionless fundoplication using the Esophix device, and it works by restoring all aspects of the EG junction sphincter, including the flap valve. In panel A, you see the device retroflexed, and there's a helical retractor that will pull the G junction down into the tissue mold, the tissue mold closes, and fasteners are placed to create an omega-shaped flap valve, which is typically 3 to 4 centimeters in length and about 270 to 300 degrees in terms of RAP, and this helps to restore the original function of the flap valve. So a good anti-reflux surgery or procedure would first include reducing the hernia as well as repairing the cura, and here after the hernia repair, we can see that the hernia is reduced, the cura is re-approximated, but we're not done yet because we have not augmented the flap valve, and that requires a third part, which is to create the flap valve, and this is a patient who had the TIF procedure to finish the three components, so this is a concomitant laparoscopic hernia repair plus TIF to complete all three components of the anti-reflux strategy. So what about the Nissen fundoplication? Well, in this procedure, the fundus is wrapped around the backside of the esophagus, creating a high-pressure zone that prevents reflux, and very much, it does augment the flap valve. However, one can argue that the flap valve may be too tight or super physiologic, and its ability to function as a flap valve, being able to open and close, may not be optimal. The 360-degree fundoplication can create inadvertent twisting and pressure points within the valve that can prevent patients from venting and suffer from gas bloat. The TIF valve, however, tends to be more uniform and is a partial fundoplication. And so working together as a team, the GI surgeon, here we have Ninh Nguyen, the chair of surgery, and he and I have been working together for many years, and as a laparoscopic surgeon, he was used to looking at the valve laparoscopically, but not so much endoscopically, and as a gastroenterologist, it would be the reverse. I would be looking at things endoscopically, but not really thinking about the laparoscopic view. And so by working together, we proposed that perhaps the optimal anti-reflux valve would be this omega flap valve. And so taking what we've learned from the TIF valve, we compare that to the other standard laparoscopic anti-reflux surgeries. This is the Nissen fundoplication, where you see the 360 wrap. The red represents the backstop, where you want the direction of the flap valve to go. In here, this vector is going more anteriorly and pretty much putting pressure on that backstop. In B is the toupee, which is a posterior wrap, and the sutures are placed anteriorly, but it's about a 270-300 degree. And here also, the flap valve is not really oriented towards the lesser curve backstop. So this is the door procedure, which is an anterior fundoplication, a partial wrap. And again, the orientation is anterior, and you're not moving the flap valve towards that lesser curve, and it's not a 270 or 300 degree. And so taking what we've learned from the TIF valve, we propose that perhaps the fundoplication can be tweaked so that it is actually flapping towards that lesser curve backstop in a way that is restoring the natural function of the flap valve with length, decreased diameter, and this flap valve mechanism to be restored, and we call this the omega valve. And so to summarize, I tried to highlight that many GERD patients who are refractory PPI are not receiving antireflux surgery or procedure and may well benefit from it, and that gastroenterologists and surgeons need to work together as a team with many good antireflux options for the patients, and finally that the personalized approach to the GERD patient includes a thorough understanding of anatomic alterations, so please remember the CORA and remember the flap valve. Thank you.

minimally invasive endoscopic

GERD

antireflux surgery

gastroenterologists

anatomical alterations