The Colorectal Quiz Episode 1: ARM - Low Bulbar Fistula

Published: 2021-01-13

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Inside this episode

Kai, the Library's AI content creator, listened to this episode and mapped who's speaking, the chapters, key claims, and cases. Every item links to the exact moment in the recording.

AI-enriched

Who's speaking

Rod Gerardo — host
Jason Fisher — guest
Mark Levitt — guest

Chapters

0:00Case Presentation and Initial Assessment — Introduction of a full-term neonate with imperforate anus at 20 hours of life with no meconium passage. Discussion of initial workup including VACTERL association screening.
3:01VACTERL Workup and Imaging Strategy — Detailed review of associated anomalies screening (vertebral, cardiac, esophageal, renal, limb), sacral ratio assessment, and the rationale for 24-hour cross-table lateral radiograph to allow the baby to declare the level of the defect.
6:06Cross-Table Lateral Interpretation and Prognostic Factors — Analysis of the cross-table lateral showing air column 8.8mm from skin, well-formed sacrum (predicted ratio >0.7), and well-developed buttocks, all suggesting good prognosis for bowel control.
8:25Surgical Decision-Making: Primary Repair vs Colostomy — Debate between primary posterior sagittal anorectoplasty versus diverting colostomy. Agreement that the low air column makes primary repair technically feasible, but acknowledgment that colostomy remains the safer choice and was appropriately chosen by the referring surgeon.
10:59The Unexpected Fistula and Technical Considerations — Revelation of low bulbar urethral fistula on distal colostogram. Discussion of the danger of missing fistulas during primary repair, leading to urinary-fecal communication. Technical points on inspecting the anterior rectal wall, anatomic nomenclature (bulbar = at the urethral elbow), and the 5% fistula rate in Down syndrome patients.
14:01Case Summary and Closing — Recap of key teaching points: complete VACTERL workup, cross-table lateral for surgical planning, colostomy as a safe default, and mandatory intraoperative fistula exclusion even in apparent low lesions.

Key claims

3:12VACTERL association screening includes plain abdominal X-ray for vertebral abnormalities including hemivertebrae — Mark Levitt
3:34Cardiac evaluation for anorectal malformation includes both physical exam and echocardiogram — Mark Levitt
3:40Esophageal atresia screening requires NG tube passage — Mark Levitt
3:47Renal evaluation requires kidney ultrasound — Mark Levitt
3:57True sacral ratio measurements should wait until the child is 3 months of age — Mark Levitt
4:22Radiologists evaluating anorectal malformation patients should examine the presacral space with spinal ultrasound — Mark Levitt
4:33Presacral masses are rare in typical imperforate anus but found almost half the time in anal stenosis or rectal atresia defects — Mark Levitt
4:33Patients with anal stenosis or rectal atresia and presacral mass will require MRI — Mark Levitt
5:08Cross-table lateral radiograph is obtained at approximately 24 hours of life to visualize the rectal gas column position — Jason Fisher
5:44The 24-hour waiting period allows the baby to declare whether they need colostomy or might benefit from primary repair — Mark Levitt
6:10Cross-table lateral is performed with the baby prone and a bump under the buttocks to position the buttock as the highest point where air will rise — Jason Fisher
6:28A marker should be placed at the expected anal location on cross-table lateral to enable distance measurements — Jason Fisher
7:20A sacral ratio greater than 0.7 connotes very good prognosis for bowel control — Mark Levitt
7:47Well-formed buttocks and visible sphincter mechanism location on physical exam contribute to good prognosis — Jason Fisher
9:25The danger of primary posterior sagittal approach without knowing rectal location is finding midline white structures like urethra, bladder neck, or bladder instead of rectum — Mark Levitt
9:42Colostomies and distal colostograms are performed to know exactly where the rectum is and whether to approach it perineally or laparoscopically — Mark Levitt
10:34Colostomy carries its own complications both from the initial procedure and from subsequent closure — Mark Levitt
11:20Performing anoplasty without identifying and addressing a fistula can result in the child urinating through the anus postoperatively — Mark Levitt
12:09During primary posterior sagittal anorectoplasty, the posterior rectal wall should be opened and the anterior wall inspected to rule out fistula — Mark Levitt
12:17In low rectal lesions, inspecting and dissecting a small portion of the anterior rectal wall will usually rule out fistula — Mark Levitt
12:34Low bulbar fistulas are located very close to the rectum, requiring careful plane dissection — Jason Fisher
13:00Bulbar fistula nomenclature refers to anatomic location at the elbow of the urethra — Jason Fisher
13:4495% of Down syndrome patients with anorectal malformation have no fistula, but 5% do have fistulas — Mark Levitt
13:44Distal colostogram should still be performed in Down syndrome patients with imperforate anus despite the low fistula rate — Mark Levitt

Cases discussed

1:52Full-term male neonate with imperforate anus, well-formed buttocks and normal-appearing dimple, no meconium passage at 20 hours of life

Points of disagreement

8:25Primary posterior sagittal anorectoplasty versus colostomy in this case
- Jason Fisher: In real life on a Tuesday afternoon with this imaging showing air column so close to skin, would likely perform primary posterior sagittal anorectoplasty rather than the board-exam answer of diverting stoma
- Mark Levitt: Agrees primary repair is technically feasible given the low rectum, but emphasizes that the referring surgeon's choice of colostomy was the safe thing to do and the right choice, deserving of praise

Open questions

What is the optimal timing for sacral ratio measurement to balance early prognostic information with measurement accuracy?
In cases with imaging suggesting low lesions amenable to primary repair, what is the actual rate of unexpected fistulas found intraoperatively?
For the 5% of Down syndrome patients with fistulas, are there clinical or imaging predictors that could identify them preoperatively?

This episode was analyzed and enriched by Kai, the Library's AI content creator. Every item links to the moment it comes from — click a timestamp to listen in context.

Written for:

Low Bulbar Fistula in Anorectal Malformation: When Proximity Deceives

The episode's teaching points arranged as a structured lesson, building from the basics up to the finer points. Written by Kai from the episode transcript and reviewed before publishing.

For trainees · Teaching arc · AI-written, human-reviewed

The 24-Hour Declaration Period

The cross-table lateral at 24 hours serves a specific strategic purpose beyond anatomic mapping. 5:44 This waiting period allows the baby to declare whether they need colostomy or might benefit from primary repair — a low perineal fistula may pass meconium, revealing itself and changing the surgical plan. The technique matters: 6:10 the baby lies prone with a bump under the buttocks, positioning the perineum as the highest point where rectal air will rise. 6:28 Place a marker at the expected anal location to enable distance measurements between gas column and skin. What you are measuring is not just anatomy but surgical risk.

Reading Prognosis in the First Day

7:20 A sacral ratio greater than 0.7 connotes very good prognosis for bowel control, though true measurements wait until 3 months of age. 7:47 Well-formed buttocks and visible sphincter mechanism location on physical exam contribute to good prognosis. These are not abstract predictors — they answer the question families ask: will my child be potty-trained and ready for school at age four? When the cross-table lateral shows rectal gas nearly touching perineal skin, the sacrum appears well-formed, and the buttocks show good muscle development, the constellation suggests a straightforward low lesion. This is where clinical judgment diverges from anatomic appearance.

The Anterior Wall Inspection Mandate

9:25 The danger of primary posterior sagittal approach without knowing rectal location is finding midline white structures like urethra, bladder neck, or bladder instead of rectum. 9:42 Colostomies and distal colostograms are performed to know exactly where the rectum is and whether to approach it perineally or laparoscopically. But even when the rectum's location is certain — when the gas column on cross-table lateral makes the repair look like "a chip shot" — a second danger remains. 11:20 Performing anoplasty without identifying and addressing a fistula can result in the child urinating through the anus postoperatively, as Mark Levitt notes: "I have seen this done by some very good surgeons where they went in, did a beautiful anoplasty, but ignored the fistula, and the child down the road started peeing out their anus." [q4]

12:09 During primary posterior sagittal anorectoplasty, the posterior rectal wall should be opened and the anterior wall inspected to rule out fistula. 12:17 In low rectal lesions, inspecting and dissecting a small portion of the anterior rectal wall will usually rule out fistula. This is not optional even when the defect appears low and simple. The distal colostogram in this case revealed what physical exam and cross-table lateral could not: a low bulbar fistula in a rectum that appeared to be sitting directly on the perineum.

Anatomic Precision in Nomenclature

13:00 Bulbar fistula nomenclature refers to anatomic location at the elbow of the urethra — not a descriptive term but a precise anatomic designation. 12:34 Low bulbar fistulas are located very close to the rectum, requiring careful plane dissection. The proximity is the technical challenge: separating two structures that lie nearly adjacent without injuring either. Pure anatomic nomenclature enables precise communication about what the surgeon will encounter and what dissection plane must be developed.

The Down Syndrome Exception That Proves the Rule

13:44 95% of Down syndrome patients with anorectal malformation have no fistula, but 5% do have fistulas. 13:44 Distal colostogram should still be performed in Down syndrome patients with imperforate anus despite the low fistula rate. The temptation to skip imaging based on syndrome diagnosis must be resisted — the 5% who harbor fistulas will suffer the same complication of unaddressed urinary-fecal communication. Statistical likelihood does not eliminate individual risk.

The Colostomy Decision as Risk Allocation

10:34 Colostomy carries its own complications both from the initial procedure and from subsequent closure. The surgeon who performed colostomy in this case despite favorable imaging made the safe choice — they traded the known risks of colostomy and closure for certainty about fistula presence and location. Everything in medicine is a balance. The anterior wall inspection during primary repair offers an alternative path: accepting the technical demand of intraoperative fistula identification in exchange for avoiding colostomy morbidity. Both approaches are defensible. What is indefensible is proceeding without a plan to rule out fistula.

Takeaways from this story

Even in low rectal lesions that appear straightforward, open the posterior rectal wall and inspect the anterior wall to rule out fistula
Low bulbar fistulas sit very close to the rectum, requiring careful plane dissection to separate structures that lie nearly adjacent
The 24-hour wait for cross-table lateral allows the baby to declare the defect level—low lesions may pass meconium through perineal fistula
Sacral ratio >0.7, well-formed buttocks, and visible sphincter mechanism predict good bowel control and school readiness at age four
Despite 95% of Down syndrome ARM patients having no fistula, distal colostogram remains necessary to identify the 5% who do

When the Cross-Table Lateral Looks Perfect: A Low Bulbar Fistula Hiding in Plain Sight

The patient case from this episode, retold from presentation to outcome with the decisions made along the way. Written by Kai from the episode transcript and reviewed before publishing.

For the care team · Case narrative · AI-written, human-reviewed

The presentation

A full-term male neonate presented with imperforate anus and no meconium passage at 20 hours of life. The physical examination was reassuring: well-formed buttocks, a normal-appearing dimple, and a clinically identifiable sphincter mechanism location 7:47. The cross-table lateral radiograph obtained at 24 hours showed the rectal gas column just 8.8 millimeters from the perineal skin — about as low as it gets. The sacrum appeared well-formed with a predicted ratio greater than 0.7, which connotes very good prognosis for bowel control 7:20. Everything pointed toward a straightforward low lesion amenable to primary posterior sagittal anorectoplasty.

The decision point

The referring surgeon faced a choice. The imaging suggested the rectum was right there, practically touching the perineum. In a case this low, many experienced pediatric surgeons would proceed directly to primary repair — open the posterior midline, find the rectum, mobilize it down, and create the anoplasty. The alternative was a diverting colostomy, which carries its own complications both from the initial procedure and from subsequent closure 10:34, but provides definitive anatomic information through distal colostography before committing to a definitive repair approach.

The tension in this decision is real. One of the discussants described the danger of proceeding without knowing the anatomy: you may find something midline and white, like the urethra, bladder neck, or bladder itself 9:42. Colostomies and distal colostograms are performed to know exactly where the rectum is and whether to approach it perineally or laparoscopically 9:42. But when the cross-table lateral shows gas this close to the skin, that danger feels remote. The first structure encountered should be rectum.

What they did

The referring surgeon performed a diverting colostomy. The subsequent distal colostogram revealed a low bulbar urethral fistula — the fistula located at the anatomic elbow of the urethra 13:00, very close to the rectum itself 12:34.

This finding reframes the entire case. "I have seen this done by some very good surgeons where they went in, did a beautiful anoplasty, but ignored the fistula, and the child down the road started peeing out their anus" [q4]. Performing anoplasty without identifying and addressing a fistula can result in the child urinating through the anus postoperatively 11:20. The colostomy was the safe choice.

The transferable judgment

Had the surgeons in this discussion encountered this case themselves, they acknowledged they likely would have proceeded with primary repair — and would have been caught. The protection they describe is technical: during primary posterior sagittal anorectoplasty, the posterior rectal wall should be opened and the anterior wall inspected to rule out fistula 12:09. In low rectal lesions, inspecting and dissecting a small portion of the anterior rectal wall will usually rule out fistula 12:17. This maneuver converts a blind primary repair into an informed one.

The plane between rectum and urethra matters here. Low bulbar fistulas are located very close to the rectum, requiring careful plane dissection 12:34. Finding the correct tissue plane is not automatic when the structures lie this close together.

One final consideration: 95% of Down syndrome patients with anorectal malformation have no fistula, but 5% do have fistulas 13:44. Even in populations where fistulas are uncommon, distal colostogram should still be performed in Down syndrome patients with imperforate anus despite the low fistula rate 13:44. Assuming no fistula based on syndrome or imaging appearance is how these injuries happen.

The cross-table lateral remains essential — it is obtained at approximately 24 hours of life to visualize the rectal gas column position 5:08, and the 24-hour waiting period allows the baby to declare whether they need colostomy or might benefit from primary repair 5:44. But a low gas column does not guarantee the absence of a fistula. The lesson is procedural: if you proceed to primary repair based on favorable imaging, open the posterior rectal wall and inspect the anterior wall before completing the anoplasty. The alternative is a child who urinates through their anus.

Takeaways from this story

A low rectal gas column on cross-table lateral does not rule out urethral fistula — inspect the anterior rectal wall during primary repair.
Low bulbar fistulas lie very close to the rectum, requiring careful plane dissection to separate the two structures safely.
Even in Down syndrome (95% no fistula), distal colostogram is still indicated to identify the 5% with fistulas.
Performing anoplasty without addressing an unrecognized fistula results in the child urinating through the anus postoperatively.

Low Bulbar Fistula Discovered After Colostomy: When Imaging Misleads

The patient case from this episode, retold from presentation to outcome with the decisions made along the way. Written by Kai from the episode transcript and reviewed before publishing.

For specialists · Case narrative · AI-written, human-reviewed

Presentation

A full-term male neonate presented with imperforate anus, well-formed buttocks, and a normal-appearing dimple. At 20 hours of life, no meconium had passed. Initial physical examination showed well-developed buttocks with an identifiable sphincter mechanism location 7:47. The cross-table lateral radiograph obtained at 24 hours demonstrated the rectal air column 8.8 millimeters from the perineal skin, with a well-formed sacrum predicting a ratio greater than 0.7 7:20.

The Decision Point

Every finding pointed toward a straightforward low lesion amenable to primary posterior sagittal anorectoplasty. The gas column sat nearly against the skin. The sacrum appeared normal. The buttocks were well-formed. Both discussants acknowledged they would likely have proceeded directly to primary repair in real time. "I think a lot of people would have done a primary repair because they said, ah, it's a chip shot, the rectum's right there," Mark Levitt stated 9:25.

But the referring surgeon chose colostomy instead — the conservative path when any uncertainty exists about rectal location or anatomy. That decision proved prescient. The subsequent distal colostogram revealed a low bulbar urethral fistula that the imaging had not suggested.

The risk of proceeding blindly became immediately clear. One of the discussants described the danger of going in posterior sagittal without knowing where the rectum is and finding something midline and white, like the urethra, bladder neck, or bladder itself 10:50. But the more specific danger here was different: finding the rectum exactly where expected, performing a technically sound anoplasty, and never discovering the fistula. "I have seen this done by some very good surgeons where they went in, did a beautiful anoplasty, but ignored the fistula, and the child down the road started peeing out their anus" [q4].

Management

The referring surgeon performed a diverting colostomy. Colostomies and distal colostograms are performed to know exactly where the rectum is and whether to approach it perineally or laparoscopically 9:42. The colostogram demonstrated the fistula's location at the bulbar urethra — the anatomic elbow of the urethra 13:00 — positioned very close to the rectum 12:34.

Had primary repair been attempted, the approach would have required specific technical steps to avoid the outcome Levitt described. During primary posterior sagittal anorectoplasty, the posterior rectal wall should be opened and the anterior wall inspected to rule out fistula 12:09. In low rectal lesions, inspecting and dissecting a small portion of the anterior rectal wall will usually rule out fistula 12:17. The dissection must establish the correct plane between rectum and urethra, particularly critical when the fistula sits as close to the rectum as this one did 12:34.

Outcome

The outcome following colostomy and definitive repair was not discussed.

What the Case Changes

This case isolates a specific judgment error: equating a low-positioned rectum on imaging with absence of fistula. The cross-table lateral at 24 hours visualizes the rectal gas column position 5:08, allowing the surgeon to determine whether the baby needs colostomy or might benefit from primary repair 5:44. But that film does not rule out fistula. A rectum sitting 8.8 millimeters from skin can still communicate with the urinary tract.

The technical lesson is procedural. "You should never try to go in blind" [q3]. Even when the rectum's location is certain, its anterior wall anatomy is not. The anterior wall must be inspected during any primary repair, requiring deliberate dissection of that wall to exclude fistula 12:09 12:17.

The colostomy carries its own morbidity — complications from both the initial procedure and subsequent closure 10:34 — making the decision genuinely balanced rather than obvious. But the alternative morbidity is a child urinating through the anus, requiring reoperation to address a fistula that should have been managed at the initial repair.

One final consideration: 95% of Down syndrome patients with anorectal malformation have no fistula, but 5% do 13:44. Distal colostogram should still be performed in Down syndrome patients with imperforate anus despite the low fistula rate 13:44. The same principle applies to any patient where imaging suggests straightforward anatomy — the suggestion is not confirmation.

Takeaways from this story

Cross-table lateral showing low rectal gas does not exclude fistula; anterior rectal wall must be inspected during primary repair
Low bulbar fistulas sit very close to rectum, requiring careful plane dissection to separate structures safely
Colostomy with distal colostogram remains the safe choice when any anatomic uncertainty exists, despite its own morbidity
Five percent of Down syndrome patients with imperforate anus have fistulas; distal colostogram still indicated

Topic overview

A case-based discussion of a full-term male neonate with anorectal malformation presenting with no anal opening and no meconium passage at 20 hours of life. Cross-table lateral radiograph at 24 hours showed the rectal air column 8.8 millimeters from the perineal skin with a well-formed sacrum. Despite imaging suggesting a straightforward low lesion amenable to primary posterior sagittal anorectoplasty, subsequent distal colostogram after colostomy revealed an unexpected low bulbar urethral fistula. The case illustrates the critical importance of ruling out fistulas intraoperatively even in apparently low lesions, as 5% of Down syndrome patients and some non-syndromic patients harbor fistulas that can lead to urinary-fecal communication if missed.

Key takeaways

Cross-table lateral at 24h guides repair approach; measure rectal gas to skin with marker at expected anal site for accuracy. (5:08)
Always inspect anterior rectal wall intraoperatively in low lesions—5% of Down syndrome ARM cases harbor unexpected fistulas. (12:09)
Missed fistulas cause urinary-fecal communication postop; colostogram or intraoperative inspection prevents this complication. (11:20)
Sacral ratio >0.7, well-formed buttocks, and visible sphincter on exam predict good continence prognosis in ARM patients. (7:20)

Keywords

anorectal malformation imperforate anus VACTERL association vertebral abnormalities hemivertebrae cardiac defect esophageal atresia renal abnormalities limb abnormalities presacral mass anal stenosis rectal atresia low bulbar fistula urethral fistula Down syndrome

Hashtags

#PediatricSurgery #ColorectalSurgery #AnorectalMalformation #NeonatalCare

Transcript

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Pediatric colorectal surgery. It just sounds really complex, right? These patients can come with anatomic variances, really rare anomalies, their care can be complex, dynamic, multidisciplinary, and pose a lot of clinical challenges to your everyday pediatric surgeon. I mean, just me mentioning this, I bet there's a case that popped up in your mind that was a real head scratcher that you've never seen before. At those times, it might be nice to just step inside the mind of a pediatric colorectal surgeon who's been around the block. Oh, this is really exciting, don't you think? Careful what you wish for. I mean, we've known each other for 20 plus years, and now we're doing the Zoom thing. That's Doctor Jason Fisher. He's a pediatric colorectal surgeon at Cincinnati Children's, and he's talking to one of his best friends, pediatric colorectal surgeon out in DC at Children's National Hospital, Doctor Mark Levitt. Jason was visiting Mount Sinai to check out the program, and I was giving my chief resident grand rounds on, guess what, colorectal surgery. It this is honest to true story. Their friendship, I can only describe as those two funny uncles at the barbecue. They're smiling, laughing with each other, but they're also two renowned colorectal surgeons who are clearly passionate about this specialty. So, without further ado, this is the colorectal quiz. This is a case that was sent to me by um a surgeon, um, and um I know what the surgeon did, but we're gonna play it out like you are in the neonatal ICU and there's a brand new baby, full term born with imperfor anus. He shares the screen and shows an image of a neonate, a male, with an obvious anorectal malformation. There's a little dimple there where the anus should be. All right, so this is a full-term baby, seems to be perfused well, uh, breathing room air, and obviously no anal opening. But I will tell you, it looks like there might be something there, but there's not. There's no meconium that has passed, and now we are at about 20 hours of life, and it still looks like that. So, Mark, could I pause you for a second? Yeah, during those 1st 20 hours. What are some of the key things that You would want to work up on this child as we are sitting here, hoping that we see some meconium come out from that little dimple in the anal area. Yeah, well, you know, of course, um, this is a baby with an anorectal malformation, so we need to make sure we check out any associated malformations. So, remember that mnemonic from general surgery residency, Val, so V vertebral abnormalities. Plain X-ray of the abdomen, tells you about the spine, makes sure there's no hemivertebrae. A is anorectal malformations, which is why we're having this podcast, and then C, cardiac abnormalities. We want to make sure we've checked for any cardiac defect, both on exam and on echo. E is esophageal atresia, so they ought to get an NG tube pass. R for renal abnormalities. Um, so they need a kidney ultrasound. And then L, limb abnormalities, but you should be able to find those mostly on physical exam. I also like to get a sense of the sacrum. I, I do like to measure the sacral ratio, but of course, Wait until the child is 3 months of age to make the true sacral ratio measurements, but it does give you a feel for how normal this pelvis has developed. I always worry about a missed presacral mass. Yeah, I think it's one of the other good reasons of viewing an AP view of the of the spine, because you can see if there's a hemisacrum. Of course, the spinal ultrasound, if your radiologists are attuned to diagnosing the interectal malformation patients, they ought to look at the presacral space with their ultrasound. Uh, luckily, it's pretty rare to find a presacral mass, but of course, if it's an anal stenosis or erectile atresia defect, then you You need to be very worried about finding a presacral mass and almost half the time you'll find one, and those patients will end up getting an MRI. This patient looks like a pretty typical uh imperforrate anus with no flow of meconium. And the interesting thing here to me is it looks like the dimple is pretty normal looking and the buttock looks pretty well formed. But despite that, we're at 20 hours with no meconium. So what's the next step? We typically get at about the 24 hour mark, give or take a few hours, a cross table lateral to see what does the gas column look like. Uh, in this patient. Is there a low gas column that looks like it's almost touching the skin, or is it pretty high up? And that might dictate what your next steps might be. And obviously, during this time, we're also making sure the patient is doing well, getting resuscitated, and that the abdomen's not getting distended to a point that we need to intervene before waiting this 24 hours for a cross table lateral. Yeah, no, I agree, and of course it's important that if this baby was born today, we're not rushing to do anything, because we need time to have this baby declare themselves to either be someone who's gonna need a colostomy or someone who might be able to benefit from a primary repair, a meconium, if a if a perineal fistula bubbles up. Then Doctor Levitt pulls up the cross table lateral film. It's important to note, and I didn't mention that the baby is now prone, putting the buttock really at the highest point where air will rise to. And you can get, you can get this X-ray at the bedside in the neonatal unit, just put the baby on a, on a bump under the buttocks. I, I think it's important and it's pretty glaring in this X-ray, that you mark where you think the anus is appropriate, so you could get your measurements and get an understanding of what the distances are going to be depending on your next steps and potential operative uh repair or approach. Yeah, I don't know what they put there. It looks like a Might be a silver dollar. Yeah, uh, that could, that could be. First of all, it's a beautiful image. It's very, uh, straight on lateral. The air column has really risen very nicely, and boy is that thing close to the perineal skin. It's right there, isn't it? It's an impressive film. It's a great one. Yeah, the other thing I would note, um, again, and I wouldn't calculate a sacral ratio at this stage, but the sacrum looks quite normal. I bet this kid is gonna have a pretty normal acal ratio, certainly greater than 0.7. Which connotes a very good prognosis for bowel control and really peace of mind for the family. They want to know what's going to happen to this baby in 4 years when they need to potty train and go to school. Just adding to the prognosis and just putting the picture together. When we looked at the baby, the image of the baby, and, and looking at his perineum at that. Point. It did look like there is a well-formed buttock, good muscle. It looked like there was a true area where you could determine where the sphincter mech mechanism was going to be located in alignment with also seeing a well-developed sacrum and all these other things. All these things lead together to likely a good prognosis. So you have a baby with a low rectum, an air column that is just about 8.8 millimeters from the skin, a normal sacrum, and buttocks that appear to be well developed. So, What's next? Well, I have two answers for you, Mark. I think if I was sitting in a hotel room, being examined by a bunch of board examiners, my answer would likely be a diverting stoma in real life, which is what we're discussing here. What would we do in, in, uh, on a Tuesday afternoon? I, I think. This air column is, if you're gonna get this X-ray and base your decision making on where the air column is, and what's going on. I'm pretty apt to say, I might perform a primary posterior sagittal inter ectoplasty with this type of imaging in front of me. You know, I think, I think the key to deciding whether to dive into a perineum and posterior sagiti is, where is the rectum? You wanna know that the what structure you will find if you make a posterior sagittal or even a mini posterior sagittal incision. And there is no question in my mind that if I open posterior sagita here, the first structure I would find would be rectum, because the danger is that you go in posterior sagita, you don't know where the rectum is, and you find something midline and white, like the urethra, the bladder neck or the bladder itself. And that's why we do colostomies, and that's why we do distal colostograms. So we know exactly where the rectum is, and we know whether we should approach it perineally or whether we should do it laparoscopically. But in this case, we know we're gonna find the rectum. Maybe we should just do a primary repair. It, it goes without saying and, and one of our, I think one of our big teaching points is you should never try to go in blind. Right, we're going in with knowing that if we make a posterior sagittal incision right now, the first thing we're gonna hit is that air pocket, which is the distal rectum. So I will tell you that the surgeon who sent me this case, they did not do that. They felt more comfortable doing a colostomy, and I wanna tell you, that was the safe thing to do. Bravo to them. That was the right choice. Nothing wrong with that at all, but of course, we are giving the child a colostomy. And whatever complications can happen from that, and we are giving the child a colostomy closure, and whatever complications can happen from that. So everything in medicine is a balance, but there is no question that the anal part has been made safer by having a colostomy. The next image blows Doctor Fisher's mind. Doctor Levitt pulls up the distal colostogram, very clearly, there is a low bulbar fistula. So, this is sort of scary, because if you went in and grabbed this rectum and did a primary anoplasty. And did not know there was a fistula, and unfortunately, I have seen this done by some very good surgeons where they went in, did a beautiful anoplasty, but ignored the fistula, and the child down the road started peeing out their anus. And that's what question mark. We both agree that probably in real life, we would have done a primary posterior sagittal approach on this patient, and we would have found the rectum, and we could have made that rectum reach the perineum and done our anoplasty. How do we handle this? Because I didn't know that there was a fistula there. This is troublesome. Yeah, I mean, I think that's, that, I think that's the key point of this case, that I think a lot of people would have done a primary repair because they said, ah, it's a chip shot, the rectum's right there. But when I do that, I open up the posterior wall of the rectum and I inspect the anterior wall of the rectum. So, for Doctor Levitt, he dissects the little bit of the anterior wall, carefully lifting it off the urinary tract. For him, in a patient like this with a low rectum, this will usually rule out the fistula. I think two other points I want to put is that you can see this fistula is very close to the rectum. And if you're going to dissect that free, and along the urethra, um, it's important to make sure that you know that those two structures are not very far apart, and getting that into that proper plane is very important. I'd also like to mention, um, the fact that we said this is a bulbar fistula. The reason why Doctor Levitt or Mark is saying that. It's a bulbar fistula, it's at the elbow. You can see it's at the elbow of the urethra. And tell us that the uh the nomenclature we like to use is an anatomic pure anatomic nomenclature saying that it's a bulbar fistula. My final question for you, Mark, or, or point is, what if this patient had trisomy 21? Would you have had a different thought process or approach? It's funny you say that question today. I got an email today from a surgeon who said I have a he has a baby with Down's and imperforate anus. Does he, does the baby need a distal colostogram, or can he assume that the baby has no fistula? And I said, no, the baby might have a fistula. 95% of Down's patients have no fistula, but 5% do. So I would still do a distal colostogram, and some of them might have a fistula. Alright, let's summarize the case. So first, make sure that you do a complete workup. There are a lot of associated anomalies with that. Make sure you also get a preoperative cross table lateral X-ray to evaluate the air column and help you with surgical planning. Once you start to look at everything, keep in mind that even if it looks like a chip shot PARP, colostomy is still a reasonable and safe choice in the meantime. Now if you do decide to go with the PAP, make sure to rule out a fistula intraoperatively. Now, here's some closing thoughts from Doctor Fisher and Doctor Levitt. Hey, I got a joke for you. Oh, go ahead. Have you seen the movie about constipation? I have not. It hasn't come out yet. Oh man, OK, thanks my friend. It was. I hope that you guys enjoyed the first of potentially several colorectal episodes. If you're listening to this on your podcast app, great. Thank you for listening, but You're missing out. So download the Stay Current Pediatric Surgery app. You can listen to this podcast and click to see the images that Doctor Fisher and Doctor Levitt are talking about. Then you could click over and watch some technique videos, or watch a video about colorectal surgery, listen to other colorectal podcasts. It's all there in the Stay Current app. Until next time, I'm Rod Gerardo from Cincinnati Children's, and remember, knowledge should be free.

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