Greetings, I'm Peter Dragunov, I practice at the University of Florida and today I wanted to discuss two main topics. One is the various tools that we use for poem and the second is to discuss some variations of the technique. Bleeding with toolbox. Of course you need an endoscope and I would suggest that endoscope with water jet function is a must in order to be able to irrigate independently from the scope channel in case of bleeding. With good technique bleeding is rarely encountered but sometimes it can be torrential and the ability to handle bleeding is essential skill set and water jet on your scope can help you dramatically. The second thing that I would suggest is to choose an endoscope with a good retroflexion. The picture to the left shows two endoscopes, same model, same make but the one retroflex is much better than the other. I tend to choose the endoscope for my cases myself, I go to the cabinet and I choose the one with the best retroflexion. A distal attachment is also a mandatory tool to have on your endoscope. I prefer the cylindrical attachment from Olympus but conical attachment from Fujifilm can help with the easier entry into the tunnel. So either one is okay and it's a matter of personal preference. I'll make it simple. For insufflation you must use carbon dioxide. Using room air has been related to a number of complications at point and it's strongly recommended to use carbon dioxide. Make sure that that is the case. On the Olympus processor it can be easy to actually inadvertently use room air and this is the 190 Olympus processor and here in the corner I wanted to point out to you that the air button must be on off. If it is on on even though you're pumping CO2 to the unit you will be using air. Make sure that the air button is pressed on off. For injection solution most of us use saline stain with a little bit of methylene blue. Don't put too much dye because if the injection fluid is too dark then you cannot easily see submucosal vessels and you can inadvertently cut through them. The recommendation is that you should be able to read your newspaper through the injectate not too dark not too light and most people do not use epinephrine although in some cases epinephrine may be of benefit but for ESD it's a little bit more controversial. For POEM you probably will be just fine without the use of epinephrine. Electrosurgical equipment. You must use a microprocessor controlled generator. There are a number of those that are available. If your unit has variety of generators make sure that you use one of the listed here from Olympus the ESG 300 or ESG 100. For ERB the newest VIO 3 it's clearly the better choice of all of the ERB options but the VIO 300, 200 or ICC 200 are also adequate. There are two main types of knife used for POEM. One is the needle type and here you see the knife from ERB. It's called the hybrid knife. I want to point out to you that the hybrid knife requires its own unit that provides injection so that requires capital equipment investment. I personally favor the ERB hybrid knife but the triangular tip knife is a very good option as well. Here on the picture to the left you have the old version of the TT knife. By the way TT stands for triangle tip and J is for the injection. The picture in the middle is the newer version with more compact tip and you can inject alongside the knife. You can use variety of other knives besides the two main ones that I showed you the hybrid and the TT knife. The ones shown here on the picture are rarely used although occasional expert prefers to use the IT2 knife particularly if you're using the myotomy, if you're doing your myotomy from distal to proximal, the clutch cutter can be used, the SB knife can be used or the speed bolt knife can be used for POEM and some experts utilize this but most of us will use the needle type of knife. It is essential to have a coagulating forceps available. I favor the one presented here in the middle. By the way all of those are from Olympus, they are in three different sizes. You can certainly also use the smallest one as well. The largest one is probably too big to utilize for POEM and is best used for ESD in the stomach but coagulating forceps, it's a must-have. Considering that you have a bunch of devices that are specifically dedicated to third space endoscopy including POEM, it makes sense to keep them all in one place to have a toolbox. In our case, we use these portable cabinets that are on wheels that we can easily wheel in and out of our somewhat smaller rooms but even if you have a large room and all of the devices are stationed there permanently, I think it's a good idea to have your devices for third space endoscopy in a dedicated cabinet so you can easily track them down. Now switching gears to techniques, I'm going to discuss a couple of variations of POEM techniques. First of all, starting with the mucosal incision, you can use a longitudinal cut or transverse cut. The longitudinal cut is the one most commonly used. It is a little bit more difficult to enter the tunnel with longitudinal cut but easier to close. If you're using a transverse cut into the mucosa, it's easier to get into the tunnel. Closure may be a little bit more challenging. I would suggest if you're using a transverse cut, still close it longitudinally rather than trying to close in a transverse fashion. The most common way of closing incision is with clips but suturing, X-TAC or over-the-scope clips have been also described as an option. But I would say that in 99% of the cases, clips is all you need. In rare occasions when closure can be very difficult, a stent can be deployed. But in most situations, it's actually not feasible because patients with akalasia have dilated esophagus and the stent cannot adequately seal the mucosal incision. So typically not a good choice but in between clips, suturing, X-TAC and OTSC, you should have enough choices to close all incisions, even the most difficult ones. Direction of the myotomy. Proximal to distal is what most experts utilize but distal to proximal with the IT2 knife, it's also an option. That usually will mean that you have to use two knives to complete the point procedure. One to do the tunneling, a needle type of knife and then the IT to do the myotomy. So that increases your procedure cost. And another downside of distal to proximal is that if you get bleeding during the myotomy, it may be a little bit harder to manage because it's away from you. It's hiding behind the uncut muscle in order to target with the coagulating forceps. So most experts use proximal to distal myotomy. The orientation of the myotomy anterior was the original description at 2 o'clock and I still favor that. Posterior is at 5 o'clock and on a rare occasion, one can go to the right-hand side on the angle of his. I don't want to routinely do that because that is a major setup for bad acid reflux because once you destroy the angle of his, you cut through the sling fibers and that predisposes the patient for bad reflux. But it can be done in some patients that have had prior failed procedures such as prior Heller myotomy or prior failed POEM procedures. The anterior or posterior approach are the two more common ones. That brings us to the important discussion of what is adequate myotomy. Obviously, we want to provide relief of dysphagia, but we at the same time, we don't want to cause much GERD. So we just want to cut enough, but not too much. And I already discussed the issue about anterior versus posterior myotomy, but also there is the full thickness versus circular selective versus partial full thickness myotomy. What is the optimal length of the myotomy in the esophagus and what is the optimal length of the myotomy in the cardiac? All those are important questions, so let me address them one at a time. The issue of anterior versus posterior myotomy actually has been studied quite extensively in a number of case series, but also for randomized control studies. And the bottom line is that as far as clinical success is concerned, judged by decreasing the Eckhart score, there is no difference in between the anterior versus the posterior approach. Although early studies suggested that with the anterior approach, you may have less GERD, a follow-up randomized control studies did not confirm that. And in this meta-analysis, as you can appreciate, there was no difference in the incidence of GERD versus in anterior versus posterior myotomy. How about full thickness versus selective myotomy versus partial full thickness myotomy? And what I mean by partial full thickness myotomy is to do a selective circular in the esophagus and when you come to the lower esophageal sphincter and the cardiac switch to full thickness. I want to point out to you that there is no high quality studies, full thickness may cause more GERD, although that has not been proven beyond a reasonable doubt. Full thickness, though, is faster to perform. And one can question whether it really matters for those of you who have been exposed to POEM that you know that that longitudinal muscle is paper thin and it splits very easily just from the pressure of the cap and most of us do a selective in the esophagus and full thickness at the LES and cardiac. One can think that if we have a better way to judge it or have a tailored myotomy based on some measurements such as endoflip, that will be better. But that approach has not been validated and it's still investigational. Short versus long esophageal myotomy. We do have this randomized control study coming out of India and they randomized 71 patients with type 1 or type 2 akalasia and the short myotomy on average was 3 centimeters in the esophagus. The long was close to 8 centimeters and to no surprise, the procedure time was much shorter with short myotomy. The clinical success, there was no difference and there was no difference in the integrated relaxation pressure. Finally, there was no difference in gastroesophageal reflux as judged by EGD and PH study. So this is the only randomized study to date. Of course, there is a meta-analysis including that study plus some case series. So I will take this data with a little bit of a grain of salt. But the bottom line is that the procedure duration was shorter with the short esophageal myotomy. Of course, no surprise there. The clinical efficacy in between short and long was the same and there was a little bit less esophagitis on both EGD and PH study with the short myotomy. At this point, those data are intriguing and I will be eagerly awaiting some more data before making a final call. But it appears that short esophageal myotomy in the range of 3 centimeters or so, it's good enough. The next question is what is adequate myotomy in the cardiac? By consensus, the optimal myotomy is 1 to 2 centimeters. But how can we accurately measure it? One traditional way is to measure from the incisors. That is not totally accurate, particularly in achalasia where the esophagus is dilated and you can get different measurements when you're pushing the scope versus pulling the scope. But we also use typical landmarks in the tunnel such as the tunnel widening once you enter the cardia. That is one of the most reliable landmarks in my opinion. The spindle vessels represented in the top right picture which are typical of the muscle of the cardiac and also penetrating vessels which are typically seen about a centimeter distal to the lower esophageal sphincter. People have used injection on epinephrine dye at the end of the tunnel and then going into the stomach and retroflexing looking for blanching of the mucosa or the double scope transillumination as demonstrated on the picture to the right, the middle picture. You put an ultra-thin scope into the tunnel and with a standard scope you retroflex into the stomach and you use the standard scope which is roughly 10 millimeters in diameter to estimate how far the tunnel is into the cardia. It's probably the most accurate way to measure the extent of the tunnel but you need two scopes, you need two light sources which is a problem in most cases. Most units don't necessarily easily have that availability at least easily and on a routine basis and bringing the travel card is cumbersome and not necessarily easy to accomplish. And to flip maybe of benefit here again we don't have definitive data it is still an area of active investigation. To summarize, you definitely need a dedicated toolbox for POEM. Most of us use a needle type of knife such as the hybrid knife or the triangular tip knife with injection capability. You must have a distal attachment or cap and you must have a coagulating forceps. As far as technique is concerned anterior and posterior myotomy appear to be equivalent and at this point full thickness versus circular versus partial full thickness myotomy can be considered equivalent although we don't have a high quality data. The length of the myotomy in the esophagus for type 1 and type 2 akalasia is still an area of active research. It appears that short 3 centimeter myotomy in the esophagus is equivalent to longer one but we need confirmatory data. For the cardia we are aiming for 1 to 2 centimeters of myotomy but measurement sometimes can be challenging. You should rely at this point mostly on anatomical landmarks. If you have the ability to use a two scopes in your unit that is probably the most accurate way to measure the extent of the tunnel in the cardia. Thank you very much.

POEM

endoscope

myotomy

electrosurgical equipment

measurement