10 ABSITE_colorectal_1_edited
[00:00:00] Okay, so here we go. Behind the knife, ab site review, colorectal is the topic today. So Kevin, talk to me about the colon. What
are the dimensions of the colon? The length and the caliber? So the colon is five to six feet in length with the rectum encompassing
approximately 15 centimeters of that. A normal caliber for it is three to eight centimeters and the sequel diameter, if it's ever greater than
nine centimeters, that's abnormal.

So John, what are our retroperitoneal portions of the colon? Yeah, so that's the ascending or the right side of the colon, and descending,
which is the left side of the colon. Right, so we got ascending, descending, our retroperitoneal, and fixed. Kevin, now blood supply to the
colon. So you have your collaterals.

Talk to me a little bit about those. Okay, so the SMA, the terminal branch, is the ileocolic artery, which supplies the terminal ileum and the
cecum. And then you have your right and middle colic arteries that supply the ascending and proximal two thirds of the transverse colon,
and that's all off the SMA.

So now we're going to our [00:01:00] IMA. This primarily supplies the left side of the colon, the left colic supplies the distal one third of the
transverse colon and the descending colon. And then you have your sigmoid branches off of the IMA. that supply the sigmoid colon and
then you have your superior rectal arteries that supply the proximal rectum.

What are our main, you know, collaterals between, you know, between our IMA? So you have your marginal arteries along the colon wall,
it connects the SMA and the IMA, and then you have your arc of realen, or the meandering mesenteric artery. And this is the smaller
connection between the SMA and IMA. Great, okay.

So you mentioned the SMA supplies the proximal two thirds, the IMA supplies the distal third. So what does that make our watershed
areas of the colon? So you have your splenic flexure, which is the kind of watershed between the IMA. It's also known as Griffith's point.
And then you have the rectal sigmoid junction, which is the watershed area between the superior and middle rectal arteries.

Also known as Sudeck's point. Okay, Kevin, I'm going to stick with you on this one since you're our vascular guy. So[00:02:00] let's go to
the rectum. What's the blood supply to the rectum? Yeah, so you have your superior rectal artery, which is a branch of the IMA, but then
you transition down to the middle rectal artery and now you're getting the flow from the internal iliac artery.

And then you have your inferior rectal artery and that's also supplied by your internal iliac artery. It's an internal pudendal branch off the
internal iliac. Okay. Now how about venous drainage of the rectum? So, superior rectal veins drain into the IMV, which drains into the
portal circulation. The middle and inferior rectal veins drain into the internal iliac vein, which drains into systemic circulation.

Yeah, that's a really important distinction. And the reason why that's really important, especially from an oncologic standpoint, is
remember that our lymphatic drainage mirrors our vasculature. So, we have that. system between our portal system and our systemic
system. So you have to remember to check for groin lymph nodes for those low rectal cancers because of that systemic drainage.

So John, what are the proximal and [00:03:00] distal extents of the rectum? So the proximal extent of the rectum starts where the splay.
The distal extent is the anal canal, which is about 15 centimeters from the anal verge. Great, yeah, so that's where you can really see
where the rectum starts is with that tinea splay, and that becomes clinically important when we talk about our resections, specifically for
diverticulitis.

So watch for that splaying of the tinea, and that's the beginning of your rectum. That's the proximal extent of the rectum. Kevin, what
defines the anal canal? So this begins at the puborectalis sling, or the anal rectal ring, and it ends at the anal verge. And this is where
you have your squamous mucosa blending with the perianal skin.

And how about the, so that's the anal canal, and then we have the anal margin. So what's the anal margin? So this extends five
centimeters radially from the squamo mucutaneous junction. Okay, perfect. Okay. So let's move on to some, some pathology and we'll
start with some benign ato rectal. So John, let's talk about anal fissures.

Where do [00:04:00] anal fissures present? anatomically. Yeah, 90 percent of these are located within the posterior midline. Females can
have anterior fissures in about 25 percent of cases. Okay. All right. So yeah, posterior midline is, is typically where we'll see those. Let's
start with our nonoperative management.

How do we nonoperatively manage anal fissures? A lot of these can be managed nonoperatively and it should be your first choice on a
test, especially somebody with a new fissure. So what you do is simply counsel patient for fiber or some other bulking agent. sits bass,
and then potentially using a topical anesthetic.

You can also consider topical nitrates. You just have to be careful. One of the major side effects of these are headaches or
lightheadedness. And then you can also consider topical calcium channel blockers that have a very similar efficacy to nitrates without the
side effects. it's a little bit institution specific, but yeah, typically you do those topical agents, this bulking psyllium agent sits baths, maybe
a little topical lidocaine.

Now, how about, is there [00:05:00] a an injection that we can do? Yeah. Some centers and some surgeons are using Botox that can help
with healing rates for those who fail the topical therapy. It's kind of the next step after nonoperative management. Okay. Yeah. So, so
Botox injections after those less invasive.

medical management and then what what's our surgical option for anal fissure? Yeah, you just have to go back about Botox. You have to
be careful and using this in patients who already have some sort of incontinence. That is the main contradication of Botox therapy. But
moving on the surgical options.

So, most surgeons would start with a lateral internal sphincterotomy. It's kind of the next step. It's kind of the standard of treatment for
most anal fissures. It has superior efficacy to non operative treatments, but it does have a very small risk of fecal incontinence. Some of
the contraindications of doing a LIS are women of childbearing age, prior obstetrical injuries.

IBD, history of sphincter dysfunction, or incontinence, like I mentioned.[00:06:00] Yeah, the way I kind of think about that is, yeah, you
already have a low, a small risk of incontinence with the lateral internal sphincterotomy. It can be very effective, but you certainly, if you
have a patient that has some pre existing incontinence or is at high risk for incontinence, you want to be very, very careful and obviously
not do that.

And you mentioned... Botox so interestingly, if, if a patient does experience incontinence with a Botox, that's also a contraindication to a
lateral internal sphincterotomy. Now how about aneocutaneous flaps? What can you tell me about those? Yeah, so aneocutaneous flap
has inferior healing rates compared to lateral internal sphincterotomies but lower incidence of fecal seepage or incontinence.

You can perform these in addition to LIS or Botox injections. Okay, great. So let's move on and let's talk about another very common
benign anorectal disease, and that's anorectal abscesses as well as fistula and ano. So, Kevin, start with anorectal abscess. Where can
we see these? Now, [00:07:00] there's a lot of, the anatomic spaces can be a little bit confusing and we will have some images in our Ab
Psy Companion that will make it more clear.

But walk us through the different anatomic spaces where we can see anorectal abscesses. So you can have the intercenteric space, this
is between the internal and external sphincter muscles. Then you can have your ischiorectal, also known as ischioanal. And this is
actually lateral to the rectal wall and the space next to the ischiotubercle.

You can have your perirectal or perianal, so it's right around the anus. You can have your super levator, and this is above the levator
muscles. You can have your submucosal, and this is under the mucosa of the anal canal. And then you can have your deep post anal
space, and bilaterally, this ends in the ischiorectal fossa, with the floor being the anococcygeal ligament.

And the ceiling being the levator muscles, right? Yeah. So be familiar with those spaces, those inter sympteric, ischiorectal, perirectal,
perianal, super levator, submucosal, that deep post anal space where you can form abscesses. And this will [00:08:00] also help you
understand. Those fistula and anal and we start to talk about our cryptoglandular theory for fistula and, and, and anal formation.

So for sticking with anal rectal abscesses, what's the primary treatment? Yeah, so like any other abscess you need to drain these. Okay,
so let's say, take a step back and think about those different spaces still. So let's say we have a abscess in the superficial perianal or
ischiorectal space. How do you approach that?

So we're doing external incision and drainage. Yeah, so external incision and drainage for those ones that are accessible. So how about
those deeper ones like those deep interesting terec and those super levator ones? Those are gonna be difficult to drain externally. What
would you do with that? Yeah, in this case you can actually do an internal transanal drainage.

Yeah, internal transanal drainage for those, those deeper ones. How about a horseshoe abscess in that deep post anal space? We have
an abscess in that deep post anal space that has that, that horseshoe anatomy. [00:09:00] Yeah, so for these you can do a modified
Hanley procedure, which is when you have the posterior midline incision with the bilateral counter incision.

Yeah, it's important to understand, again, that space and how that space communicates. So you're gonna need to do a posterior midline
incision and those counter incisions to really drain that space. Okay, so, you know, drainage is the primary treatment for anorectal
abscesses. What's the role of antibiotics?

Who needs antibiotics after a drainage? So only if there's cellulitis or systemic signs of infections, or if the patient is immunosuppressed.
Yeah, so yeah, definitely think about, you know, these can progress to, to, you know, Fournier's and very bad infections. So you want to
keep in mind your patients who are immunosuppressed, including diabetics.

But yeah, cellulitis, signs of systemic infection, immunosuppression. John. What's the risk? So there's an association between anorectal
abscesses and fissional aneo. What's the risk of developing a fissional aneo? Yeah, one third of these patients with an anal [00:10:00]
abscess will develop a fistula and anal.

Yeah, that's the association. About a third. You know, it's a little bit of a chicken and egg type thing. Like I mentioned before, there's a
cryptoglandular theory of fistula and anal formation. Whether a fistula leads to abscesses or abscesses results in fistula. So, probably a
little bit of both. So, certainly patients who have recurrent peri rectal abscesses, there's likely an underlying fistula that you need to find.

Kevin, sticking with fistula and anal, now you talked about our spaces before, so let's, let's go through that again and now with the idea of,
with fistulas in mind. So how are anal fistula defined, what are those relationships to those sphincter muscles and those spaces? Okay,
yeah, so it's very similar to how you classify the abscesses.

So you have your interstingteric, which is the most common type and runs between the internal and external sphincter muscles. Then you
have your transphincteric, which runs across both the internal and external sphincter muscles. In this, you can categorize these as high
with greater than one third of the muscle [00:11:00] complex or low, less than one third of the muscle complex.

And then you have your suprastinctaric, which runs between the muscles and up and over the external sphincter. And then you have your
extrastinctaric, which runs over and above of the sphincter complex, and then your submucosal. Yeah, exactly. So we define these by
their, their track and their relationship to the sphincters, because that's obviously surgically and clinically important to how we manage
these.

So intersphincteric, transphincteric, submucosal. Again, refer back to that image to really understand those, the, the anal rectal anatomy,
those spaces, and that relationship to the sphincter muscles will be very important. So Kevin, what are the general principles of
management for a fistula and anal? Yeah, so if it's superficial, a simple fistula with minimal or no sphincter involvement discovered at the
time of an IND from abscess, it's okay to perform a fistulotomy at the time of drainage.

Okay, good. Yeah, your fistulotomies can be really your most definitive, but obviously you can't cut through somebody's entire sphincter
[00:12:00] muscle and make them incontinent, you're not really doing them any favors. So, yeah, that's great. So, what if it does involve
more, you know, than say 25 percent of the sphincters?

Yeah, so you want to make sure the abscess is drained and you can place a seton. And then, over time, that seton will induce fibrosis of
the tract. And now you're converting it from a high fistula to a low fistula and prepare the track for later procedures. You know, we'll see,
sometimes we'll see that written out on the test as a draining seton versus a cutting seton.

You know, cutting setons are really the thing of the past. So if they do try to trick you with that, just make sure that you're choosing the
draining seton. John, let's kick it over to you. So, what, what's an other, let's say you do have a higher fistula that's not. Amenable to a
simple fistulotomy.

What are some other options? So you have a couple of different options. It's usually surgeon preference, but one option is the lift
procedure, which is a ligation of intersphincteric fistula tract. And like you mentioned, it's good option for complex fistulas that aren't, aren't
amenable to just a simple fistulotomy, which would be obviously be [00:13:00] your first choice.

Another option would be the anal rectal advancement flap. And you can perform this in addition to the lift. Yeah, perfect. So yeah, you're
dissecting between those sphincter muscles and you're ligating that intersphincteric track. And then, as you mentioned, that's often done
in conjunction with an anorectal advancement flap.

And there's been good data to show good efficacy with some combination of those treatments. You'll see a lot of things, and historically
people have tried a lot of things to get fistulas closed. Fistula plugs, fiber and glue. with various reports of success. There are people that
are still doing those things.

In general, they're not that efficacious and they're likely not going to be the answer on the test. Okay, so moving on, but we're still within
benign enorectal, let's talk about hemorrhoids. Very common. So Kevin, just what are hemorrhoids? Yeah, so these are your vascular
cushions or sinusoids in the anal canal that help with gross continence.

Yeah, and what's important to remember is they're a natural, anatomic structure. Everybody has hemorrhoids. That's what I always tell
patients is everybody has hemorrhoids. [00:14:00] What is the vision or that distinction between internal and external hemorrhoids? Yeah,
so you have your dentate or pectinate line.

And why is that important? So innervation is somatic, below the dentate line, and autonomic, above it. Yeah, so, so external hemorrhoids
hurt, internal hemorrhoids generally bleed, and it's also important when we talk about treatment. You can make an enemy for life if you
band an external hemorrhoid, but you can certainly band internal hemorrhoids in clinic.

What are common symptoms of hemorrhoidal disease? Yeah, so you can have bleeding, swelling, you can have a thrombosed
hemorrhoid. Internal hemorrhoids predominantly prolapse and bleed. External hemorrhoids predominantly present with pain after clotting.
Yeah, okay, so yeah, like I said internal hemorrhoids bleed, external hemorrhoids are painful, bleeding, swelling, itching, you know, pain
and thrombosis are all things that can happen.

In reality, most people will have, who have problems with hemorrhoids will have mixed hemorrhoids. It will be internal and external
components, but certainly need to understand [00:15:00] that anatomy. There's a classification system for internal hemorrhoids. So it's
one through four. So what is that classification system?

Yeah, so one through four. So one is internal only. Two is prolapse that spontaneously reduce. Three is prolapse, but you can manually
reduce them. And four is prolapse and they are not reducible. Okay. Management of hemorrhoids. Similar to the other anorectal
diseases, bowel hygiene, no prolonged sitting or straining at the toilet, high fiber diet, plenty of fluid.

Yeah. So yeah, you're the, you get your 25 to 30 grams a day. You get your 64 ounces of water. You leave your phone outside of the
bathroom. Don't sit there playing angry birds and a lot of it's dueling habits. So that's a good initial treatment. Now what if you have very
symptomatic disease that's refractory to those lifestyle changes?

Yeah. So for the internal hemorrhoids, you can ban these. There are some risks to this. You could cause pain, bleeding, ulcer, and there's
a very small risk of Fournier's Green Gearing. And then for symptomatic or thrombosed external [00:16:00] hemorrhoids, they can be
excised. Okay. Yeah, there's a couple different ways to do that.

You're not going to be really tested on the details of that, so we won't get into that. But yeah, banding is a good option for internal
hemorrhoids, you know, mixed or if there's external components and surgical hemorrhoidectomy. But only after... You correct those
underlying lifestyle changes that needs to be done before surgery.

Okay, so moving on, let's move on to diverticulitis, which is a very high yield topic. So John, what's the HENCHE classification? Yeah, this
is the classification we use clinically to kind of help describe what we're seeing, typically after a CT scan, and also helps guide our
treatment. And there's a few variations on this, but for the basics of it, so stage 1 HENCHE, is a periclonic abscess that is less than 4
centimeters.

And we can typically treat these with antibiotics alone. Stage 2 hinchy is a pelvic or an interloop abscess or an abscess greater than 4
centimeters in size. [00:17:00] We treat these with antibiotics plus a drain placement typically. Stage 3 hinchy is where you move into
purulent peritonitis. So this will also be treated with resuscitation antibiotics and most likely an operation.

And finally, stage four, Henshi, is fecal and peritonitis, and once again, resuscitation, antibiotics, and more likely an operation. Okay. Now
you said drain placement for those larger abscesses. Now, are we talking about a surgically placed drain, or who's placing that drain?
Yeah, typically we talk to our colleagues about you know, a percutaneous drain.

Okay, good. When we talk about diverticulitis, we often classify it as uncomplicated or complicated. So what constitutes complicated
diverticulitis? Yeah, so there's many different things that can cause it to be complicated. So perforation, abscess, fistula, obstruction, or
stricture. And this is not just in an acute period too.
So phlegmon, which is a contained area inflammation, or extra luminal gas alone does not[00:18:00] constitute complicated disease.
Yeah. That's a great point. So you can have actually a decent amount of extra peritoneal gas or free air. And as long as that patient is
stable, you can treat those patients often non operatively successfully.

How about, so let's start, let's start simple. So we have a patient who's clinically stable, reliable, who has uncomplicated disease and can
tolerate oral hydration. How are you going to approach that patient? Yeah, a lot of times surgeons don't even see these patients, they end
up in the emergency room with their primary care physicians, but it's outpatient treatment with oral antibiotics to cover both gram positive
and gram negative.

So we, you'd augmentin or a levoflagel regimen. Okay, so how about patients who can't tolerate oral hydration? These are the patients
that would require admission, IV hydration, or IV antibiotics. And our usually go to antibiotics are zosyn or levoflagyl, like mentioned
before, but in the IV form. Some of those just based off CT [00:19:00] may then also require operative or percutaneous intervention
depending on the abscess size.

or how their clinical course goes. Okay. So what about, you know, it seems obvious, but let's talk about it. The patient's unstable, has
diffuse peritonitis. Yeah, these are the patients, like we mentioned that you need to start antibiotics, resuscitate them and take them to the
OR for urgent sigmoid colectomy.

So, you know, there is pretty good literature now to support primary anastomosis, even in the setting of Hynchie 3 and 4 disease. The
decision should really be based on the patient's physiologic status. So, on the outside, you know, if the patient's unstable, diversion is
likely the safest answer, but If you have a stable patient, certainly there's no reason not to hook that patient back up.

I would avoid things like laparoscopic lavage. This is still being done some places, but the data is very mixed and it's very controversial,
so avoid selecting laparoscopic lavage in these settings. If you're in the OR urgently or emergently with diverticulitis, [00:20:00] the
answer is going to be resect. Okay, now let's get back to that that patient who's, who's stable, who has an abscess on CT.

What are you thinking about and how do you want to address that? Yeah, this is a conversation you have and it's, it's, it's patient based.
So every single patient's a little different. It depends on the size, but in general. Less than three centimeters will generally resolve with
antibiotics greater than three centimeters.

We should consider percutaneous drainage If it's amenable to drainage based on anatomy. Yeah, so, you know, we're our interventional
radiologists are very good and We're going after smaller and smaller Abscesses, you know in practice if they can get to it, they're
probably gonna drain it But yeah, like you said you'll see a few different cutoffs three centimeters five centimeters, but small abscesses
can be treated with antibiotics.

If it's larger and you do have a good target, interventional radiology, placing a drain can be very beneficial and speed up that recovery. So
what if the abscess is inaccessible by IR and it's [00:21:00] not resolving, they're kind of smoldering on antibiotics? Yeah, I'd say this is
also controversial, but this patient might be a candidate for laparoscopic drain placement.

There's some other people too. You just say do the colectomy if you're going to the OR either way. Yeah, so Good. So the way I would
answer that I think if they give you a clear target and it's an abscess and maybe it's a Pelvic abscess those type of things. Yeah,
laparoscopic brain placement is an option And then there's also as you say those kind of smoldering diverticulitis that will just need to go
for a colectomy and it's like you say, it's based on the individual patient.

You know, overall goal is to let that acute phase resolve so the patient can undergo an elective, you know, single stage colectomy. You
know, much better chance of being able to hook them up with a primary anastomosis and avoiding that diversion. So let's say John, that
you have a patient who has a single episode of uncomplicated diverticulitis diagnosed on abdominal CT who is successfully treated non
operatively.

What do you [00:22:00] still need to do with that patient? Yeah, so these patients need colonoscopies if they haven't had one recently.
Typically perform these about six weeks after resolution of the diverticulitis episode. They want to rule out underlying ischemia, IBD or
potential neoplasm. Yeah, in reality that risk of missing an underlying malignancy is really thought to kind of be overblown and there's
more and more of the trend to just ensuring that that patient is up to date on their colonoscopies, up to date on their screening
colonoscopies and not higher risk.

But yeah, you should definitely be thinking about that and if they haven't had a colonoscopy, they need to be getting one. So when do you
recommend an elective sigmoid colectomy, say for uncomplicated disease? So yeah, this is a complex question, but in general, there's a
few things you want to talk to the patient about and it's a very individualized discussion with the patient.

So, it's based on a number of episodes and age of the patient. However, we do know that the first[00:23:00] episode tends to be the
worst and there's, it could be followed by multiple uncomplicated episodes. It does not necessarily increase the risk of ever needing an
emergent colectomy and stomach, so we can wait a little longer for most of these patients.

We want to consider the risk of surgery for each patient to include their comorbidities and their general health what other things do they
have going on. And then we also want to consider if they're having diverticulitis episodes, you know, like every twice a year or once a
year or once every three years, what that kind of effect would be on their lifestyle and their career.

We also have the concern, as there is suspicion for neoplasm, either on imaging, obviously if there is something on colonoscopy during
the preoperative workup, then we want to go ahead and take that colon out. And then the chronic symptoms, and this is the majority of
patients. The patients with smoldering disease, they have their acute set of pain and then they just have pain constantly going forward.

Yeah. So the good news is with these type of things where it's controversial and there's a complex decision making[00:24:00] algorithm
there on the ab site, they'll make it really obvious. They're not, they're not gonna make it tricky. So they'll make somebody who's just has
recurrent, recurrent episodes. It's, it's affecting their life and those types of things.

And they may ask you what you recommend and your rectum elective colectomy. So it won't be subtle on the exam. How about what do
we do with complicated disease? Yeah, these are the patients obviously your patients with peritonitis are the operating room when they
come in, in general. Complicated disease, those with, you know, large abscesses, an elective colectomy should be offered after the initial
recovery.

From the complicated episode. Yeah, I will say that that's even a little bit controversial for patients who, you know, have successfully been
managed with an IR drain or whether or not they absolutely need a colectomy. In general, that should probably be offered. And again, on
the outside, it's going to be very clear with, with these kind of controversial areas.

So Kevin, back to you. So we're, let's talk about a C. diff, clostridium difficile[00:25:00] infection. So what is a C. diff? Yeah, so for non
severe disease, the standard of care now is oral vancomycin for 10 days. There are some people that are becoming more resistant to
vancomycin, and so you can go to fidaximycin.

It's more expensive, but it can be effective in the patients that are resistant to vancomycin. And then flagyl still remains an option. Great,
yeah, so for non severe disease, vancomycin is your first choice, and as you say, fedoxamycin is also an option due to developing
resistances. Okay, so that's non severe disease, how about severe disease?

So for severe disease, your options are oral vancomycin or oral fedoxamycin for 10 days. Flagyl is not recommended. Okay, fulminant
disease? So this one is oral vancomycin with IV flagyl. Rectal vancomycin can be given if the patient has an ileus. Yeah, so I think a way
of simplifying that, and I think it's actually more simple than it had been previously.

is that oral vancomycin has really become a go to for most [00:26:00] initial presentations of C. diff. If the patient has severe, you know,
systemic disease, you want to consider adding IV metronidazole to that, but oral vanc... It's going to be the answer for most scenarios
with the addition of IV if the patient is very sick.

And then rectal vancomycin if the patient has an ileus, because again, you want the vancomycin. It, it does not act systemically, it acts
locally and needs to get to the colon. Okay, what about the first recurrence? So that we just talked about was the initial presentation, but
let's say they have a recurrence of their C.

diff. So for this Fidexomycin is what you go to if vancomycin was initially used. Yeah, you might see that on the outside. So if somebody
has a recurrence of C. diff, the answer is going to be Fidexomycin. How about their, let's say they have a second recurrence even after
that. It gets a little more complicated here, but you could use a longer course of vancomycin, a longer course of fideximycin, you can even
go to rifaximin or a combination thereof.

Okay, so let's say a patient just keeps getting it, [00:27:00] they just, over and over, they get treated with antibiotics and they just keep
getting recurrent C. diff infections. Yeah, so this is where you can consider a fecal microbiome transplant in patients with recurrent C. diff.
Perfect. When is surgery required for C.

diff? Yeah, so this is reserved for patients that have severe colitis that fails to respond to medical therapy. Yeah, so this can be a very
difficult decision. So outside of obvious indications like Perforation and generalized peritonitis, the decision to operate can be very difficult.
So if you get to the point of multi system failure, that's a very ominous sign and you've waited too long.

And perforation is also associated with high mortality. Consider early operative intervention and patients require invasive pressures and
signs of impending sepsis. So if we are in this situation, Kevin, what's our, what's our, what is our surgery? It's our procedure of choice.
Yeah. So you're going to do a subtotal Yeah.

So that's right. ileostomy. There are places that are doing, and people have probably heard of this, diverting loop[00:28:00] ileostomy,
colonic cleavage, antegrade bacon myosin enemas. That is an option, but I wouldn't answer that on the exam. Okay, so John, moving on.
Let's talk about colonic volvulus. Let's start with the sigmoid volvulus.

So what will we see on sigmoid volvulus? So this is your bent inner tube sign. Another way I think about it, and it's easier for me to
remember, is that The apex of what that looks like, that bent near tube, points up to the right upper quadrant. Right, so an apex pointing to
the right upper quadrant. And we'll distinguish that from sacral volvulus here in a minute.

So sigmoid volvulus apex on a radiograph points to the right upper quadrant. So that's one of those images that you're going to want to
look up, because you may be presented with that radiograph on the exam, and asked what the next steps are. So what are your next
steps, Sean? Yeah, we mostly would start with a contrast enhanced CT which would help confirm the diagnosis and also assess whether
that colon is still viable.

Okay, so if [00:29:00] there's no colonic ischemia or perforation on the CT scan, what can you do? Yeah, this is where you go and think
the first step would be, especially if the patient's stable and they have no signs of peritonitis. Endoscopic detortion with a decompression
tube left in place for one to three days.

Okay. Would be your first step. Yeah. Good, good. Those do have a high long-term recurrence rate after their initial endoscopic detour.
So you should consider a sigmoid colectomy during that index admission in appropriate patients, which would be most patients. So let's
say if you have an emergent indication for a, a, a surgery and you have is ischemia or, or perforation, what operation are you performing?

Yeah, your safest answer here, especially the patients in extremis, is it going to be an open sigmoidectomy with an enclostomy. Okay,
and how about in let's say you're able to successfully detource them what is in a semi elective setting, what's a surgical option? For an
appropriate patient, an open sigmoid.

Or a laparoscopic [00:30:00] sigmoid with anastomosis would be appropriate. Yeah. So, you know, generally these are, you know, skinny,
frail patients and they have a big distended colon. So most of the time we're doing these open. Something you think about is the patient's
status. If they're bed bound and maybe incontinent at baseline, you know, even in a semi elective setting, a Hartman's procedure might be
the best option.

On the test, it's usually going to be an elderly nursing home patient. And there's an association with antipsychotics. And as well as a
history of, of constipation. So that's going to be your little vignette that's going to tip you off to what you're dealing with on, on the, on the
ab site. So let's move on then to cecal volvulus.

So we said sigmoid volvulus has the apex pointed to the right upper quadrant. What's the radioreferent finding for a cecal volvulus? Yeah,
it's the coffee bean pointing to the left upper quadrant. Once again, I just worry about where the apex of that is and it's pointing to the left
upper quadrant. All right.

So how do you want to manage this? So, in contrast to sigmoid volvulus, endoscopic reduction is not[00:31:00] recommended. These
patients in general need to go to the operating room after resuscitation and starting antibiotics. Yeah, and what, what kind of resection
and what operation are you going to do? Yeah, so the safe answer for the test for this is performing a right hemicolectomy.

or an iliocytectomy with a primary anastomosis. Yep, exactly. So you don't ever want to choose a sarcostomy endoscopic detortion,
operative detortion and I would not pexi these. These are for a the answer is take them to the O. R. and perform a resection. Okay, so,
Kevin, moving on. So, acute colonic pseudoobstruction, otherwise known as OGLVs.

What are risk factors for for patients developing ogies? Yeah, so the biggest risk factors are opiates in electrolyte abnormalities. So
patients with OG vs. We are concerned about perforation. So where do they perforate and, and what are risk factors for perforations?
Yeah, so once the. Secum is getting greater than 12 centimeters or that it's prolonged greater than six days.

Then they're at higher risk of[00:32:00] perforation. Yeah, that's where they perforate, right? The secum is, is where you'll see these,
these perforate. So let's say there's no signs of ischemia and the secum is less than 12 centimeters. So what's your initial treatment?
Yeah. So supportive care. You want to correct the underlying cause such as electrolytes and you want to make sure the food are
suscitated.

You really want to minimize the narcotics. And then of course, treat any underlying infections and bowel rest with decompression. Yeah,
so initial treatment is supportive. Again, yeah, decompress, replace those electrolytes, try and reverse whatever is causing the pseudo
obstruction. But what if they're not improving with supportive care?

So that's when you go to the neostigmine. Okay. And what is how does that work and what is it? And what do you have to be worried
about? What's the most common side of it? So it's an anti acetylcholinesterase and it promotes colonic transit. And the most common side
effect is bradycardia, so you need to make sure they're in a monitored setting.

Yeah, so you need to have this patient in the ICU on a monitored bed while you're doing this. So what[00:33:00] if they're not responsive
to neostigmine or neostigmine is contraindicated? So this is when you can consider an endoscopic decompression. Yeah, especially if
you're getting up there in that 12 centimeters.

You don't want to let it sit like that. So yeah, if they're not responsive, there's a contraindication. You need to get them endoscopically
decompressed. Well, let's say unfortunately the patient perforated or they have signs of ischemia. Yeah, so at this point you need to go to
the OR and perform a resection, and then you can use your general principles to decide whether you're doing an ostomy versus an
anastomosis with diversion.

And one thing we definitely should mention when we talk about pseudo obstruction is we need to confirm that it's actually a pseudo
obstruction and there's not a distal obstruction, especially if we're thinking about giving neostigmine so we'll need to make sure that
there's not a malignancy or a stricture there distally that's, that's actually the cause and never just assume that it's Ogilvy's.

All right, John, so moving on now onto rectal prolapse. So how do you diagnose rectal prolapse? So rectal prolapse is a full thickness
[00:34:00] interception of the rectal wall, which has visible concentric rings. It's important to differentiate this from prolapse hemorrhoids,
which do not have the concentric ring.

Good. Okay. What kind of patients? What's a common patient presentation? Typically the patient you see on the exam is an elderly
female. It does have other associations with those who are developmentally delayed and patients with psychiatric comorbidities. And also
people with multiple medications chronic straining and diarrhea.

So what's the mainstay of treatment? So surgery is the mainstay treatment here. In low risk individuals, you can consider a
transabdominal rectal fixation or rectopexy. This can be done open or laparoscopic and they have equivalent recurrence rates. You do
have improved morbidity from a laparoscopic approach.

The opexy portion of that is the key component. If the patient has constipation chronic constipation, can you consider adding an LAR or a
sigmoid resection to the opexy? Now, what about [00:35:00] higher risk? So you said low risk. What about those high risk populations?
Those older patients with multiple comorbidities who you don't think are really gonna tolerate a general anesthetic and certainly likely not
pneumoperitoneum.

Yeah, the answer you're going to be looking for here is the Altmeier procedure, which is a perineal proctosing moidectomy. It has lower
morbidity, but higher occurrence and it's less durable in general. Okay. And then of course, long term, you know, these patients, as you
mentioned, are constantly constipated.

So, we need to do that high fiber diet and all those diet and lifestyle things that we talked about when we were talking about things like
diverticulitis, correct? Yeah. Okay. Okay. So we're going to do some quick hits and then we're going to take a break and then we're going
to come back with part two of colorectal because I know we're all getting tired.

I'm sure you're getting tired of listening. So take a break and go outside. But before that, let's hit some quick hits. So Kevin, what is the
main nutrient of colonocytes? So it's butyrate, which is a short chain fatty acid. Okay. And how's that different from the small bowel?
Glutamine is the primary [00:36:00] source for small bowel enterocytes.

Great. John, you have a patient with a sigmoid volvulus on CT. And on endoscopy, mucosa was found to be dusky with ulceration. So,
what's your next step? Yeah, you want to abort the endoscopy at this time and just proceed to the operating room for an urgent
sigmoidectomy. Okay, good. Kevin, a patient with an anal fissure, lateral, again a lateral anal fissure, or multiple fissures.

So, what are you worried about in that patient? Yeah, the first thing I'm worried about is Crohn's disease. But you can also have things
such as HIV, syphilis, and tuberculosis. Sure. Remember, 90 percent of those fissures are posterior midline. Sometimes in females, they
have an anterior midline. So if you see those lateral ones, you want to worry about these other disease processes.

So, John, you take a patient, a septic patient, with fulminant C. diff for an exploratory laparotomy. And you're planning on doing a total
abdominal colectomy, as you should, but when you open the abdomen, the colon looks totally normal. So what do you do? Yeah, this is
both a real life clinical scenario and it's something you see on [00:37:00] tests as well.

So you want to proceed with a total abdominal colectomy and an endileostomy as C. diff is a mucosal disease and you're not going to see
anything on the outside. Yeah, exactly. So remember that C. diff is a mucosal disease so the colon is very likely going to look normal but
it's still all got to come out.

Kevin, what's the first step in a lower GI bleed? Yeah. So like most things you need to resuscitate. So two large IVs, type and cross,
transfuse, admit to the ICU for monitoring. Okay, good. Okay. Now the next step is to localize the source. So how do you do that? How do
you localize a lower GI bleed? What are your steps?

So first you have to rule out an upper GI source, as that can be very common. And typically you do this with the EGD. And then after that
you have a couple options to identify the location. You can do a colonoscopy. You can do angiography or tagged red blood cell scan. I'd
probably choose colonoscopy on the exam.

So recommendation of which to perform varies by institution, but like we said, colonoscopy is probably the best answer for the test. Yeah,
I would agree with that colonoscopy is probably the best answer. I would, I [00:38:00] would add CTA to that as well. And again, it's very
institution dependent. You know, when I was a resident, you would never say CTA, but the cts have becoming very good and, and are a
very realistic option for localizing GI bleeding sources.

But, so let's say the patient's unstable or, or has an ongoing transfusion requirement, what do you need to do? So in that situation, you
need to do a segmental colectomy if the bleeding source is localized, either on the colonoscopy or the angiography or tag rub blood cell
scan. Okay. Let's say you've, you've done all your, your localization studies and you were not unable to localize.

So then you have to go to your total abdominal colectomy. Yeah, right. So a total abdominal colectomy is the answer there. Okay, so that
wraps it up for part one of colorectal. Go outside and take a little break and then come back and we'll see you back for part two.