Colorectal Quiz: Episode 48 - Anal Stenosis

Welcome to another episode of the Colorectal Quiz. I am Felipe Chaldish, Colorectal Research Fellow at Children's National Hospital, Washington DC, and today we'll be discussing anal stenosis. Make sure you download the app to follow along with images and other related cases. It can be downloaded from the App Store and the Google Play Store. OK. Today's episode is classically hosted by Doctor Mark Levitt from Children's National Hospital and Doctor Jason Fisher from Cincinnati Children's Hospital. Welcome, welcome. It's time for the colorectal quiz. Here we go again. It's one of my favorite uh times of the week. Jason Fisher, you're, you're pretty cold out there in the Midwest. There's some big storm, I understand. It's a little chilly out here, but it's warm with this group. Doctor Levitt will introduce our special guest from Chicago, another chilly city. All right, well, we're very excited about today. Um, we have a special guest, um, also coming to us from the Midwest. We, we should do this like, um, smart list where it's like a little bit of a secret who the guest is, so people lead up to the anticipation. This surgeon, um, very special, uh, friend, and, uh, Leader in her field um at Laurie Children's and is now the uh director of colorectal surgery there in Chicago, um, and a wonderful institution. Julia Grybowski, thank you for joining us. Well, thank you for having me. I'm honored. Doctor Grybowski has a case to discuss for 10 month old baby with constipation. Let's get the story. He's 10 months old, and he was presenting with constipation. And to quote unquote evaluate for Hirschsprung disease. He had been seen at several outside institutions um for this complaint of constipation, and then finally made it to Larry Children's. Um, his mom reports that he was born full term, that he passed meconium within the 1st 24 hours of life. She started to notice that when he was about 4 to 5 months old, when he started eating some purees, she noticed that he was stooling less often. Throughout this workup, he was sent to gastroenterology, where he was started on lactose. Lows, but that didn't help much. Unfortunately, he started getting more distended with palpable stool burden in the left lower quadrant. His anus appeared to be within the muscle complex. It looked like relatively normal, although it was hard to get a very good look, and the digital rectal examination was difficult, um, just because of his discomfort and he was really straining. Let's, let's take a moment and talk about that. What is the pediatrician's role? In checking out the anus anatomy and making sure a surgeon doesn't need to get involved. What, what does this mean to you? What would you tell your pediatrician who calls you, I think of the pediatrician is nervous. Just have him come on over. We all get referrals. The pediatrician says the anus doesn't look right. They think it's an anorectal malformation. We are routine, and I'm sure Jason and Julie, you agree, we don't schedule any tests of any kind. We see that patient, and I would say 9 out of 10 times, it's completely normal exam. And the patient goes about their life and they just need some management of constipation. Now, this is the first point, and Doctor Fisher explains what exactly they're looking for on the anal exam. When I get these patients and they're a little difficult, it's sometimes a two two-person job. It's a two-person job to do this, and you get an assistant, whether it be a medical assistant, a nurse, whomever is helping you in clinic. To hold the legs at the knees and bend them back and get a good exam. And then you could look for the sphincter complex like you were describing in this case, it seems like anus is located within the sphincter complex, but on digital rectal exam, it's tight. I like to actually get a number. I like to use a Hagar dilator and actually get data. Two things I wanna say about that. One is I agree with the exam. You need to push the perineal body down and make it flat, so you can really see that this is particularly relevant in a girl, that the perineal body has adequate length to it. You see where the opening is, you can tell whether it's a fistula, or if it's a normal appearing anus. You can look at the Sphincter mechanism, you can make a determination, is this anal exit normal or abnormal. OK, so then, like in this patient, what if the anal opening appears normally located? Then I think you need to make sure it doesn't look skin-lined or funnel shaped. Sometimes that's a clue that there may be an anal stenosis. I will tell you relevant to your Hagar story, I had a patient in clinic. This is about 2 years ago. A fellow came to the clinic. I sent them in to evaluate a very similar patient to this. And they did what you said, Jason, and they checked with a Hagar dilator, and they reported to me that everything was normal, and that number, you know, 11 slid in without a problem, and the kid just needs treatment for constipation. And I went in and I did a digital rectal exam with my pinky, and I felt an anal stenosis, and it was a very good lesson for that fellow that the Hagar can slide right in, even if there is a fixed stenotic area. It feels scarred, but you can only detect that. I don't mean scarred because it's congenital, but it feels uh tight. Um, and it feels like a, like abnormal tissue. And the only way you know that is if you put your finger in there. I do agree with the size. A real anal stenosis, a very tight one, obviously, is very small, but you could have an anal stenosis that fits an 11. And although uncommon, this diagnosis can get missed without a thorough physical exam. And I just took care of last week an unbelievable case of a 5-year-old who was followed for constipation all those times, saw 3 gastroenterologists for difficult to manage constipation, and I was the first one to do an actual digital rectal exam. And the kid had an anal stenosis and a presacral mass that was never diagnosed. So, please, do a rectal exam with your 5th digit and get a feel for what is a supple anal opening and what is a stenotic anal opening. I've, I've seen people put a Hagar dilator in about 4 millimeters and say everything's OK and not really go further and this this anal atresia could also be a distal rectal stenosis or atresia and you need to and that's where the digital rectal exam if you really get your pinky in and and get it to a couple of knuckles depth. You, you'll know you're, you know, you're checking out the distal hindgut. OK, pause before we move forward, we need to get some of the nomenclature sorted. What exactly do we refer to as a stenosis versus atresia? I would use the term anal stenosis. In a patient like this because there's a narrow if this is what this is or sort of talking about, you know, I'm guessing that there's gonna be a problem here, but it's not an atresia, a, a, a rectal atresia you would have known in the newborn. You should have known, yes, well, the kid wouldn't have passed anything. And probably would have gotten a colostomy, but people do use the term anal atresia, and I don't like that term. There is such a thing as rectal atresia where the anal canal is pretty normal, certainly normally located, but there's a segment where there isn't anything, and then there's normal dilated rectum above. Alright, let's get back to the case. So just to recap, this is a 10 month old infant presenting with constipation and a concern for abnormal rectal exam. And so he presented to the pediatric surgery office and obtained some imaging, which you can see on the sticker app. There's a plain abdominal X-ray. Which I can uh report looks like it's uh a lot of impacted stool and a contrast study which has A rectosigmoid the size of Illinois, about the shape of Illinois also, and a more normal caliber um proximal sigmoid and left colon. So, very impressive uh study all the way down to the bottom of a dilated rectosigmoid. In a baby that was only 10 months old, which is pretty impressive. Yeah, so this clearly demonstrates. That there is some obstruction leading to the dilatation. You know, if you're ever wondering whether a narrowing is clinically relevant, you have to ask yourself, is there proximal dilatation? Um, you know, if you're worried about an anastomotic problem, if there's proptimal dilatation, the anastomosis could be. This kid was taken to the operating room and under anesthesia had a full thickness rectal biopsy due to concern for Hirschprung disease, and in the operating room, he had a narrow anal canal above the dented line, about 1 centimeter.5 mm, and a biopsy was performed. Jason, would you do a biopsy for such a patient? That's a great question. Um, I probably If you see abnormal anatomy, I probably would not be doing a biopsy on this patient. And because sometimes you get information you really don't want to know. Well, well, the, it's. Here's the thing, I, I agree. There's, I, I really don't like giving a patient two diagnoses, and we have an obvious explanation for obstruction. Um, I'm not, it's very unlikely that we have an anal stenosis and a Hirschprung's. I wouldn't biopsy, and to Jason's point. If you do biopsy, you're probably gonna be biopsying the narrowed area, and the narrowed area typically might show no ganglion cells, and very, very sadly, there have been patients who have been misdiagnosed with having Hirschsprung's disease. And they never had Hirschberg's disease, and then their rectum is removed, and then because of perhaps an inner underlying anorectal malformation, which is what they had. They really needed that rectum for the proprioception it provided. So I think I also would not have biopsied. And another part of the problem is if you biopsy right above the stenosis, you will see hypertrophic nerves because of the chronic constipation, which is a topic we have discussed on a prior podcast. So, be sure to check that out. What may happen, and we've also talked about this, you might sample an area that has no ganglion cells and hypertrophic nerves. But I will tell you, if you have savvy pathologists, they ought to run a Cretinin in that situation. And I bet in that situation, the calretinin is present, which means there are ganglion cells nearby, which means it's not Hirschbrun's. But I wouldn't even go down that road and I wouldn't even do a biopsy. In this case, I would say, uh-huh, it's anal stenosis. We have something to fix. Let's fix it. And the only time that Doctor Fisher would do a biopsy in a lower tract obstruction would be for if there is an atresia. I would do a rectal biopsy because there is somewhere between a 1 and 3 or 7%. It's mixed data, but somewhere in the low, a real percentage of patients are have an associated Hirschprung's disease, right? But just different situation. But just to be clear, that's a colonic atresia. Most of those are, there's a right colon only. We're talking here about an anal problem, right, um, but I completely agree, if you have colonic atresia, you should biopsy. But in this case, it's an anal stenosis, so no biopsy needed. But of course this patient did get a biopsy, and so the results were difficult to interpret. The biopsy showed that there were hypertrophic nerves and no ganglion cells. Oh, so someone concluded this patient has Hirschberg's disease, right? Well, That was the initial concern. However, one of the interesting things about this pathology that was done is that they had frozen the entire section, so no permanent was done. But being a savvy team, we looked through this pathology with the pathologist, as well as we reviewed that he had a narrowed anal canal and this history that doesn't really correspond that well with Hirschsprung disease and this barium enema that doesn't really look like a barium enema significant for Hirschprung disease. So there was a concern that there was a misdiagnosis, and so no plans were made for a pull through, and instead they planned to redo the biopsy and redo an exam. That was very smart. By the way, one of the clues to too low is No ganglion cells, but no comment on the nerves. Another clue to too low is squamous epithelium identified. That's a big, but this, this pathology that you just recited, I am very impressed that you said let's repeat it. And thank goodness you did, because this. I would have been shocked if you would have told me this was Hirschprung's disease, but you repeated it and it's not Hirschsprung's disease, is that right? It is not Hirschprung disease. A month later, the child is back in the operating room and needed to be dilated again with concern for anal stenosis. So at that time, we looked at his, his weight trend and how he had been doing for the month and a half that we had known him, and he was failing to thrive, had had several hospitalizations and outside hospital for emesis, and so my partner did a diverting ileostomy. And then the plan is going to be to do clean him out a little bit, give him some time to rest, and then he will have an operation for his anal stenosis. Additionally, he's going to get a pelvic and spinal MRI because anal stenosis can be associated with a presacal mass. Obviously, anal stenosis has about a 40% risk of a presacral mass. Yes. And if you do have a presacral mass, you need to be absolutely certain that that mass is not in any way connected to the dura, so you need both a pelvic and a spinal MRI. It is really important to associate an anal stenosis with a presacral mass, but you need to know how that, if that mass is present, which is approximately 40% of the time. You need to know if that's involved with the dura or not. And if you just get a pre-sacal, if you just click, you know, pelvic MRI, you might not get that information and you could get yourself in a lot of trouble. So this patient was diverted, especially important since he had a massively dilated colon. Here we are with a properly diverted patient who's gonna grow and be happy, a screened pelvis to make sure there's no presacral mass, and now we have an anal uh challenge on our hand. Uh, on our hands. Now to the crux of the management of this case, how to manage anal stenosis. Let me just mention, some people dilate these things and don't offer surgery, and I think for a very low, like skin level stenosis, screen for presacal mass, great, dilate. You might solve the problem that way, but that is exceedingly rare. Most of them, and this one as you've described it, is a little bit in, maybe 1 centimeter or so. Dilations are not going to be successful, it's gonna come back. That I like that when you talk about dilating versus not dilating and at the skin level stenosis, I think that those are great ones to dilate. But also, we have had for those skin level stenosis, which are pretty rare, done a stricture, like a true strictplasty like we do for strictures after a PSAC, but those are ones that are right at the, at the skin level where you Put your finger, you can barely get your finger in, you can barely get your Hagar in, as opposed to this one, which was a little bit deeper where we could see a nice, pretty healthy looking dentate line, pretty normal looking dentate line. So this patient will need surgery and a core principle will be preservation of the anal canal. So then it turns into the operation where you can do essentially like a, I don't know how to describe it, a half of a PA, where you just open the posterior part of the anal canal and Just open that back while you um can you keep in continuity the anterior 180 and you have a very it's well said. I think picture of it in a paper. I think that is very well said in that you're preserving or not you, you're avoiding and not in a danger area, the anterior part of the anal canal where you could injure more anterior structures. Male or female vagina or urethra. Whereas if you work posteriorly, you have more freedom to do work. You advance a pliable part of the distal rectum, do a colo anal anastomosis there. Preserving at least 50% or more of your dentate line and the sensation in that area. And the theory is that you will give a better chance of long-term continence and should have a great chance of long-term continence in this patient. Mark's thoughts on your approach to uh surgical procedure. I agree, do not get rid of the anal canal. We will link a great article to this episode comparing a contrasting anal stenosis with rectal atresia. Be sure to have the take current app to see the article linked below. So, the technical challenge is that in this case, you want it open posterior sagitally as was just described. The anal canal, which is the narrow part, now flops open from a circle to a hemicircle. So take that to the bank, that anal canal that's now a hemicircle stays a hemicircle. How do you fill the back hemicircle, the posterior hemicircle, that's mobilization of the rectal wall forward, so that the posterior part is colon, columnar epithelium to skin, and the anterior part is the original anal canal. And therefore you have an anal canal, albeit on the anterior half only, and good sphincters cause these patients always have good sphincters, and thereby you are going to preserve continence. That's the plan for this patient in today's case, of course, after his MRI results are reviewed, but that's not the end of this case because there's still one aspect about this child's findings that needs to be addressed. What about that big balloon animal behind us? Stenotic region. What are we doing with that? Oh, oh, you mean the humongous rectosigmoid that looks like the state of Illinois, State of Illinois. I thought it was the Snoopy in the Macy's Day Parade, but sure, whatever you wanna call it, it's big. It is big. Well, I guess the question is, is, do we think that that rectum, once emptied and given a little bit of time, will that shrink down to normal? Sounds like yes. The answer to that, in my view, is yes. You need to get rid of the distal obstruction. Give it some time. You can always come back and do a sigmoid resection. Sure can, but I tell, I will tell you, you need to solve the anal problem first. I would not say that colon will get back to normal from an anatomic standpoint. I think if you do a contrast study two years later, it's still going to be dilated. The more important question is, will it function? And then I think yes, I 100% agree. You give it a chance to see if it functions and then if it doesn't down the road, yes, you could go in and either resect. I've been doing tapering of these balloon animal type rectums and sigmoids that get dilated because of a distal obstruction. But I agree, most of these will function well. They might need a little assistance, some motility agents, etc. to help, help move stool along a little bit, but in, for the most part, you should be able to get by without having to go back in and do A resection of some type. This can also be facilitated with a malone to aid movement of stool with antegrade flushes, which means these kids don't need sigmoid resections. These principles has been supported by research presented at recent EPSA meetings. In Columbus, we had this initiative that started a number of years back where we said Malone only, let's track them. Would you like to guess how many of those patients, it was about 100, I think it was 111 patients, how many of those patients Got a sigmoid resection, or let's put it this way, how many patients did not need a sigmoid resection? 97%, 97% responded to Malone only. 3% got a sigmoid resection, and would you like to know something that was common to the 3 percenters? Pelvic floor dysynergia on their anorectal manometry. In retrospect, those patients who underwent a sigmoid resection probably should have gotten pelvic floor physical therapy. And maybe would have avoided their sigmoid resection. So now the sigmoid colons of the world are a little bit safer, thanks to this new data. Yeah, for sure. That's right. All right, so everyone's been waiting, they've been suffering through this, waiting for the joke, right? Julia, wow us with your joke. OK, well, I just wanted to tell you guys that poop jokes aren't my favorite. But they are a solid #2. You know, we, we, we considered we considered having t-shirts that said, your #2 is our #1 priority. My brother thinks you should change the name of the podcast to No ifs, ands, or buts. I do like that. Does he copyright that, or could we own it? He didn't. He said he would give it to you. All right, listen, Julia, um, we really appreciate that the children of Illinois and the central states are lucky to have you. Thank you all for joining us for this episode of the Colorectal Quiz, and remember to download the current app from the Apple App Store or the Google Play Store to check out the images and algorithms we discussed in this episode. Additionally, remember to follow us on social media and check out our YouTube channel for more pediatric surgery content.