Colorectal Collaboration: Neurogastroenterology/Motility Disorders

Hey there listeners. This is Rod Gerardo, research resident at Cincinnati Children's Hospital Medical Center. Whether you're watching us on YouTube, listening to us on Apple Podcast, Stitcher, Spotify, SoundCloud, the best way to listen is on the Stay Current Pediatric Surgery app. It's brought to you by Cincinnati Children's Hospital Medical Center, Children's Mercy at Kansas City, and the Journal of Pediatric Surgery. It's in the Apple App Store, it's in the Google Play Store. Download it today, but until then, enjoy the episode. And I told you that we're going to do some more colorectal video podcasts like this. So, I didn't want to leave you hanging. So today we're going to have a chat with Dr. Jason Frischer. He is the Director of the Colorectal Center at Cincinnati Children's Hospital Medical Center. And Dr. Ajay Kohli. He is the Director of the Neurogastroenterology and Motility Disorders Specialist at Cincinnati Children's Hospital Medical Center. And they're going to talk about an area where pediatric surgery and Peds GI kind of overlap: manometry in the setting of anorectal malformations. So without further ado, Dr. Kohli, take it away. Manometry is really a catheter-based study of pressure changes within the lumen of the gut. So it really entails visual pattern recognition of the tracings and identifying any deviation from the normal. To get a basic understanding of colonic motility, let's put it this way. It's broken down into four key components. The diameter of the colon, the tone, the compliance of the colonic wall, contraction pressures, how strong the contractions are, and then the length of the colon. Okay, let's take for example megacolon. What would you expect and what would you see? The tone and compliance are usually abnormal, but the colonic manometry may still show normal high amplitude propagated contractions and the transit may be normal. Oftentimes we see a megacolon, we assume or we presume that the tone and compliance is going to be abnormal, the the transit's going to be abnormal, and the surgeons um um right, correctly or wrongly will say, oh well, this is a non-functional colon. Let's remove it. All right, let's define a few more things, like constipation. Let's break it down into three aspects. I guess that's six, three aspects. There's three types. There's a normal transit constipation. In other words, the train makes it to the station on time. And there's a slow transit constipation where there is a problem with the um uh the neuromuscular integrity of the colonic wall. That means it's getting to the station, but it might take a little bit longer than usual. And then the third, which is the most common in our population including the anorectal malformation children is outlet obstruction or withholding. I guess to complete the metaphor here, this would be like there's construction or damage to the railway and you can't get there. So when you talk about transit, there are three ways that you can really study bowel transit. So this is a sitz marker study. The patient will ingest some radiopaque markers. We wait about five days and then we get an x-ray to see where those markers are. Usually a patient should be able to poop out all of those markers in five days. But some remaining at the end of five days like shown in the left picture here, and the right, it kind of indicates that the transit may be um abnormal. Okay, so let's break down these two images. So in the left picture, what you're really seeing is a um almost all of the markers at the end of 10 at the end of five days are collected down in the rectum. And the rectum obviously is dilated. So so that's a little bit more indicative of an outlet obstruction or withholding. How about the other picture? On the right, you see the marker scattered all over the colon, which is indicative of a slow transit constipation. The second way to really study colonic transit is doing a scintigraphy. Uh it's a little bit more involved and you essentially study the geometric center of the isotope after the child ingests that. Okay, that sounded like super complex, but basically the patient will ingest this radioisotope, wait a little bit, and then nuclear medicine will take some images. We can find a specific location in the colon that's having transit issues. And this is an example of colonic inertia where you see the isotope that's retained in the colon mostly in the transverse and ascending colon. Okay, what's the third option? Is using the the newly um available smart pill. It's been in the market for a few years, uh but the problem is that it's a pretty large uh sized capsule that needs to be ingested. Okay, so this is for a kid who's maybe 10 or 12 years old. What is it measuring? pH, temperature, and pressure. And then this little black piece here, that's like the radio signal that you can just attach like a belt clip, and then it communicates with the pill. What does that reading end up looking like? So this is a tracing of a smart pill. Um essentially, you can see the pH drops when it's in the stomach, when it enters into the small intestine and the duodenum, the pH goes up, becomes alkaline, then it drops again as it enters into the ileum, which is slightly acidic, and then when it's excreted, the temperature drops when it um is in the toilet bowl. Okay, so you're really measuring the transit time from the mouth to the anus. Now that one's probably normal. What about like an abnormal one? This is an example of a delayed gastric emptying and delayed colonic transit. You can see here that the capsule reached the cecum and then it stayed in the colon for all this time. All right, so to keep with the theme here, we're going to break down another term: colonic contractions. And there's a couple different types. Phasic or brief contractions or tonic sustained contractions, then there are segmental non-propagated contractions, which are the most common, and then of course you have the propagated contractions, which we are interested in. Now the low amplitude contractions, we're not so worried about those. They do help move gas through the colon. But the one we're interested in, the high amplitude propagated contractions really is what moves the stool along the length of the colon and that's what the radiologists see on a contrast enema and refer to as the mass movement. Now there are also a couple factors that can affect your contractions and when they happen. When you wake up in the morning, there's a stimulus to the colonic motility and this is known as the orthocolonic reflex. And then when you eat, you have the gastrocolonic reflex. And then on top of that, you can use senosides or bisacodyl to induce an HAPC. Um let's like take a deeper dive into HAPCs. Majority of these originate in the proximal colon and most do not really propagate beyond the mid colon. A fewer than 5% really reach the rectum. Now normally when you have an HAPC, then you should have a reflex where the internal anal sphincter will relax so that you can help move along this mass movement, this bowel movement. Which is referred to as the Colo anal reflex and that's why the internal sphincter and the external sphincters relax to allow the stool to be evacuated. All right, so in case you've never seen it before, this is what the manometry card's going to look like and then these are the probes that they use to get these readings. We place these catheters typically while doing an endoscopy. However, our radiologists, interventional radiologists can also place these in IR. Um the reason we do endoscopy to place these catheters is because it gives us a chance to actually evaluate the mucosa in the colon when we're placing the manometry catheters. Also make note that they have the C arm in there. You have fluoroscopy because you want to know exactly where you are while you're doing this test. This is a schematic of a colonic manometry catheter that's in the colon. That's the transverse colon, descending, sigmoid, and the rectum. And then look at the right. This is basically watching that HAPC go along the colon and then at the bottom there at the rectum, you can see all those multiple little spikes. That's something else. That's called the rectal motor complex. Here is a good example. There's quiescence between two high amplitude contractions starting in the top, in the cecum going down to the sigmoid, and these are other high amplitude contractions starting in the mid colon going down to the um sigmoid. And just like we said before, if you follow that HAPC all the way down when it gets to the sigmoid of the rectum, you can see the internal anal sphincter is going to relax so that the patient can defecate. Here's a sample of a kind of a different view in a patient who is going to get bisacodyl. So in this uh tracing, you see a conventional uh manometry tracing where you see segmental dysmotility. So if you're going from top to bottom of this reading, then you're actually going from right to left of the colon. So you see how there are those HAPCs on the right side of the colon. And then as you move down that page, you're going to the left of the colon and there's like no HAPCs there. Sometimes when we get reports from you or we're in discussion, that's Dr. Frischer. You are able to give us segmental dysfunction of a colon and sometimes it says the distal 30 cm, distal 60 cm or the right colon. When do you think it's appropriate for us to what what is your treatment algorithm once you get this information? Now keep in mind, the decision isn't like just based on the manometry, it's also based on the imaging, like a contrast enema, and then the physical exam and then the history that the patient and the family is giving you. Um if you do have a segmental dysmotility, you have to decide how much of that, how much of the segment is involved. Is it a 10 cm like you alluded to or is it 40 or 50 or entire left side of the colon not working. Typically we our recommendations are if there is more than 40 to 50 cm of colon that's not working, does not have HAPCs, that's a dysfunctional colon. But just because they've come to that conclusion doesn't mean we're going to jump to surgery just yet. But I think our management style now here at Cincinnati Children's has been to try to maximize medical therapy, understand the anatomic and functional issues, and then if we can't overcome those issues with medical management, resort to surgical intervention and potential resection. The first step like you said is to maximize our stimulant laxatives and make sure that they're evacuating and if that's not helping then you could potentially go to um um irrigations or or enemas. And if that doesn't help then you start talking about the other surgical interventions. I want to stress that we shouldn't resort to resection right away just because we have one abnormal finding. All right, so now that we're all caught up on the basics, let's do a case. So this is the case I wanted to discuss real quick. We have a 13month old female that was referred to us from an outside hospital with a history of anal stenosis. I know this is not very exciting for you guys, but um the child had had a P followed by anal wound breakdown at the outside hospital and had a diverting colostomy and mucus fistula creation. After takedown off the colostomy, she had recurrence of symptoms of abdominal distension, constipation and therefore had a reversal of colostomy and mucus fistula. She continued to have poor appetite and poor weight gain gagging and vomiting and uh her constipation was associated with abdominal bloating and fuzziness. The only thing that helped her constipation was irrigations. She gets a gastric emptying study. She gets diagnosed with gastroparesis. She's tolerating her NG tubes really well. What is the concern from the surgeon? And to answer that, Dr. Frischer's going to talk about how they work through these patients when they get them. One you have to ensure normal anatomy. And so I think the first step I would do is to ensure that we have a no anatomic issues at hand. Perfect. Okay, but the thing is that gastroparesis in and of itself isn't going to explain all of these symptoms, right? So when Dr. Frischer's talking about anatomy, there's a really great way we could just check the anatomy from the esophagus down to the stomach, down to the small and large intestines. We can get some contrast studies. Here is the contrast enema that was done at an outside hospital Jason. This is what you were looking for. Anatomy wise does not look too bad. No, looks great. This is the upper GI again from the outside hospital. The stomach is a little bit enlarged, which you would typically expect in a child that has gastroparesis. And then the other thing you want to make sure you note on that upper GI, the patient doesn't have any small bowel pathology like a malro or something like that. So what did we do next? Well, this is a pediatric surgery podcast. So spoiler alert, we operated. So we took him to the OR and the surgeons uh Jason Dr. Frischer actually looked at this kid and Dr. Breach did her the gynic exam. It was uh the anus was positioned within the sphincter complex, muscle slightly more prominent posteriorly but completely surrounding the anus, accommodated a 14 Hagar easily and the the perennial body was about 2.5 cm and then on the gynecological exam, things were pretty much normal. So what did we do next? We did a manometry study because we wanted to make sure that the child does not have any small bowel dysmotility or colonic motility. The manometry of the small bowel and colon were normal. So the only part of the gut that really was abnormal was the gastric emptying. So then I guess you're left wondering, did the duodenal and colonic manometry really help in this patient? And I would say the answer is yes because you you ruled out a more widespread uh dysmotility. And that information is invaluable, especially in a patient like this who has an anorectal malformation. So there you have it. The basics of what a surgeon should know about colonic manometry from their pediatric gastroenterologist. Because let's face it, when it comes to colorectal surgery, the best way to treat a patient is with a good team. Did you love this episode? Did you hate it? Either way, leave us a comment, whether you're watching us on YouTube, listening to us on Apple Podcast, Stitcher, Spotify, SoundCloud. Or the Stay Current Pediatric Surgery app. It's in the Apple App Store, it's in the Google Play Store. Download it today, but until then, I'm Rod from Cincinnati Children's and remember, knowledge should be free.