All right, we'll move on to polypectomy techniques. So you'll see what we talked about in terms of removing lesions here. What we're going to do now is look at polypectomy and polypectomy technique in specific. And what we're going to do at this point is we're going to do a method called snare polypectomy. Now a snare is simply a lasso that's used when we're looking at removing, let's say, valves or other lesions from the gastrointestinal tract, whether that be the colon or in the stomach or other areas. And so this lasso comes in a variety of different shapes, sizes, as well as filaments or the wire that's used to create that metal lasso. What I'm doing right now is I'm going to show you this particular snare. They essentially work by the principle of if we pull, you'll see that there's a loop that comes out, and this can be used to place around a polyp. Again, they're different shapes and sizes. When we take something cold, it's just the wire itself that guillotines the tissue or cuts it. When we say that we're taking something hot, then we use electrosurgery or electrocautery to make the wire cut or coagulate through tissue. When you're doing something hot, it's what's called monopolar. So what we always need to use to complete the circuit is a grounding pad. This is what you'll see be placed onto a patient so that the circuit can be completed. One thing to watch for when you do place grounding pads is that you don't have what's called tenting or air between the skin and the surface, or you can get thermal injuries or burns. You want to make sure that this is flat against the patient's skin. You also want to make sure that there's no objects in the way, such as EKG leads or other catheters that are being used, or they can cause injury as well to your patient. So we'll put on the grounding pad, and I'll have our assistant help us with that. And we're going to put it on our model here. Typically, the closer you can place that in the patient to where you're actually going to be using your device is going to be the best. Remember, you're keeping that circuit very short and closed. What we'll do right now is we'll get ready to do our polypectomy. In this scenario here, we're going to do our polypectomy with a loop or a lasso, known as a snare. Again, each snare can typically be used both hot and cold. Here we have a different shape of our loop that we'll use, and we're going to get ready for electrocautery as well, so we've plugged it in to our electrosurgical generator. Remember, we have our grounding pad already on, and so we're ready to perform polypectomy either cold or hot. One thing to note, and I'll hand this to my assistant for now, would be that when we're taking off a polyp and we're using electrosurgery, we have foot pedals here. There's blue, yellow, and a center one to toggle between functions. The blue is typically when we want to coagulate. The yellow is typically depressed when we want to cut or do a blended setting. All of that is controlled by our electrosurgical generator. You'll hear a beep when I do it, and that'll be me stepping on the foot pedal. What I'm going to do now is take our snare. I'm going to hold our endoscope using proper technique. I'm going to place the snare catheter through our therapeutic channel, and it's going to get ready to come out at the end. What we'll do is we'll watch it come out so you can see what it looks like both outside of the body. We'll take it out, and we'll put it back in. When we open, can you open the snare for me? We can see it deploy out. Bring it in just a little bit. There. Perfect. You can see the tip here as well, and you can see what it looks like out of the body. Let's close this. I'm going to pull the catheter out, and we're going to put this down into our stomach phantom. We're going to get some lubrication. We'll enter the endoscope. So we enter into our stomach and we see our polyp and we're going to take this off. So we put our catheter tip out. So we go over the polyp and we ask our assistant to please open the snare. And so in this particular case what we're going to do, that's really good, we're going to place it down over the object and try to keep our snare anchored at the base. We're taking it off with cautery. So really we're trying to get minimal normal tissue involved. If we were taking it cold, meaning just guillotining it without electrocautery or electrosurgery, what we'd be doing is trying to take two to four millimeters of normal tissue with that. So let's close that snare. And close it tight. And in this particular case, different from when we guillotine it cold, we're going to tent it up off the mucosa to make sure that we have just the mucosa and no muscle or any deeper tissues trapped. We're going to make sure that it's tight. And then what we're going to do is we're going to apply our electrosurgery to this. So I'm going to start cutting. You'll hear the beep go and we'll go through and we'll guillotine it. Go ahead. Good. And as we can see we've removed that polyp. Because we're in a porcine model, the tissue, what we call flew away or went to a different area. But essentially the technique would be now to retrieve that polyp and suck it through our therapeutic channel. You typically have a basket attached to the vacuum or a trap which would trap that polyp as it came through so that it did not end up in your suction canister. That's a nice demonstration of polypectomy techniques. You again notice the blue band there and that was pre-deployed by Dr. Epstein to create a pseudopolyp inside this porcine stomach to allow him to demonstrate to you the resection. And we'll get a chance to see the banding devices and how those work in just a moment. A couple of teaching points are that the snares, as we talked about earlier in the lecture, come in various sizes and shapes to accomplish the needs that we do. Although any snare can be used as a cold snare where you just guillotine without cautery and cut through the tissue, there are some snares that are dedicated for cold resection and they typically will have a much thinner wire. And that thinner wire is designed to be able to cut through the tissue with a little more sharpness to achieve that resection. One of the questions that Jake asked is how does the lasso need to be removed? How hot does the lasso need to be to remove the polyp or tissue and cauterize without causing excessive damage? And that's again an excellent question and relates to the physics of electrosurgery. When we are trying to coagulate a blood vessel, we are using a specific type of current called coagulation current, which is typically lower frequency, lower voltage, and that creates a lower temperature. It still gets hot, but it creates a lower temperature so you're not completely destroying the tissue, but you're able to coagulate blood and activate the coagulation system. On the other hand, if we want to cut through tissue, we are typically using a current that's called a cut current, which is much higher amplitude, much higher frequency, and that creates a much higher temperature at the tissue level and essentially lices the cells. And when you lice the cells, you're basically cutting through them. And so depending on how big of a polyp it is, the size of the tissue that we're resecting, and whether or not there's likely blood vessels in the tissue will determine what setting the endoscopist is using, either coagulation current, cutting current, or more commonly a blended coagulation and cutting current where the processor, the electrosurgical unit, is able to give a program alternating cut, coag, cut, coag, cut, coag, in order to achieve the resection and still allow for coagulation. He did mention that after the polyp is resected, we do want to retrieve that tissue because we must send that tissue to our pathologist in order to understand what the diagnosis is, and if there's any worry of cancer or advanced neoplasia, we want to know how deep that is and how close it is to the margin of resection to help us understand if we have achieved a complete resection. Okay, are there any other questions? One other comment I will make again is that we are doing a lot more cold resection of polyps, but there's a limit to that. When a polyp is large enough or the tissue is thick enough, it is sometimes physically impossible to cut through the tissue with just a cold guillotine, and we must use coagulation or cut coagulation current to actually cut through those thicker pieces of tissue. So Dr. Tierney, I'll ask this one because this is a common one we typically will get is, when does a gastroenterologist determine when a capsule might be appropriate versus the more traditional endoscopic procedures that these videos are demonstrating? Very good question. The question is, when do we use a capsule endoscope? And a lot of it has to do with access, whether we can easily get to the site with a standard upper or lower endoscope. If we're fairly concerned about pathology within the small bowel, particularly the middle of the small bowel, which is not easily accessible with a traditional endoscope, we will use a capsule to first diagnose where in the small bowel this might be. Is it in the upper half of the small bowel or the lower half of the small bowel? Is it actively bleeding? Has it stopped bleeding? Is there a concern for a mask? Do we see a mask on the capsule? So the capsule can provide very important information to us in terms of what might be the underlying condition, and perhaps even more importantly, where in the small bowel is the condition? Because we do have endoscopes that can reach that area of the small bowel. It's called deep enteroscopy, but it's a much more invasive, much more involved procedure. Typically requires general anesthesia and often takes hours of time to accomplish that. And it's helpful to know if it's in the upper half or the lower half of the small bowel. So capsule is very, very informative and provides us critical information to target the next step. The other time we might use capsule that we do have a colon capsule that is now approved for colonoscopy, and it's primarily approved for doing colon imaging in people that have either failed colonoscopy or can't have colonoscopy for another reason. There's a couple of other small specialized capsules, including some for the esophagus, which are designed to non-invasively inspect the esophagus looking for Barrett's esophagus, but it turns out it's not quite as accurate as a standard upper endoscope. Okay, any other questions, Ed? Another one that we commonly get that I think is worth exploring here a little bit for your response is, is there any differentiation between disposable scopes versus the traditional reusable scopes? How do you determine which to use when? Yeah, so the disposable scopes is really a relatively recent innovation, and a lot of the issue about using disposable scopes versus reusable scopes relates to infection control and the risk of transmitting infection during gastrointestinal endoscopy, which is really very, very small, especially for standard upper and lower endoscopy. The one place where that may have some real concern is when we're doing ERCP and biliary endoscopy. There have been some severe infections set up in the biliary tree that appear to be iatrogenic or the result of interventions, and that was primarily because of the complex design of reusable duodenoscopes. And so now we have a single use, a couple of different single use duodenoscopes on the market for special circumstances if we're really concerned about an infection risk. Or if a facility, the other place where that often comes into play is if a facility really doesn't do enough, it's not a large volume center and they're not doing enough ERCPs or biliary endoscopy where they want to invest in the hardware and the endoscopes for repeated use. They can invest in the single use endoscopes and not have to worry about the capital expenditures that are much higher for reusable devices.

polypectomy techniques

snare polypectomy

gastrointestinal tract

snare shapes

snare sizes