all right this is absite and board review for anal diseases
colon and rectum is covered in a different video be sure to check that one out i had help putting
this one together from dr olga garcia who is a prior resident of mine and currently about
to graduate from colorectal surgery fellowship at case western reserve in cleveland so thanks to her
let's talk about some anatomy first the surgical anal canal is defined by the sphincter complex
and extends from the anal verge to the top of the anal rectal ring defined by sphincter muscles the
length can range from three to five centimeters with women tending to have shorter ones
understanding the anatomy is crucial to treating anal diseases such as fistulas and abscesses
the dentate or pectinate line is located at the level of the columns of morgagni which contain
the anal crypts responsible for perianal abscesses and fistulas proximal to it is
the anal transition zone farther above which is columnar epithelium that makes adenocarcinoma
the anoderm is distal to the dentate line and is lined by non-keratinized squamous epithelium so
it makes squamous cell cancers the dentate is important because it is a margin for different
innervation blood supply and venous and lymphatic drainage as well as the presence below or lack of
above it sensation lower rectum can have lymphatic drainage to internal iliac nodes
and sometimes the inguinal nodes whereas the anal canal primarily drains to inguinal lymph nodes
the anoderm is where dysplasia most commonly arises
the term anatomic anal canal usually just refers to the canal below the dentate line
as opposed to the surgical anal canal which goes to the top of the sphincter muscles
the external anal sphincter is an extension of the levator ani muscles specifically the
puborectalis muscle and has three portions called the deep superficial and subcutaneous at rest
the puborectalis muscle makes a sling around the distal rectum forming an acute angle and
with defecation the muscle relaxes allowing the anal rectal junction to straighten out
the external anal sphincter is under voluntary control the internal anal sphincter is a
continuation of the muscularis propria of the rectal wall and is under involuntary control
the groove between the two can be felt as the intersphincteric groove on the anal margins skin
rectal distension causes the internal anal sphincter to involuntarily relax and the external
anal sphincter to contract this is called the rair or rair reflex this is absent in hirschprung's
disease since the meissners or submucosal and the auerbachs or the myenteric plexuses are missing
hemorrhoids are classified as internal which are above the dentate line and external below
the dentate line internal hemorrhoids are painless and are the ones prone to bleeding
cirrhotics with portal hypertension get internal hemorrhoids from pressure in the
imv down to the superior hemorrhoidal veins and can have massive internal hemorrhoidal bleeding
internal hemorrhoids are the ones you band inject or staple not the external ones
because that would hurt internal hemorrhoids are the ones that have the grading system
grade 1 no protrusion from the anus anus grade 2 protrudes from the anus but spontaneously reduces
grade 3 need manual reduction grade four you cannot reduce the internal hemorrhoids are
the ones that have the left anterior left posterior and right lateral ones
external hemorrhoids hurt since there is somatic nerves below the dentate line
these are the hemorrhoids that get thrombosed and painful if this is less than 72 hours old
you can do surgical excision but if the patient presents after 72 hours they're on the downslope
of the curve of pain severity and should wait it out with stool softeners and sitz baths
chronic hemorrhoids can cause irritation and may be a reason to do surgical excision
always send the specimen to pathology in case there is some undiagnosed malignancy
like squamous cell cancer or anal melanoma in external hemorrhoidal crisis which are
engorged prolapse and strangulated circumferential external hemorrhoids
apply sugar and ice packs in 15 minute intervals with a goal to reduce sometimes you may even need
paralysis under anesthesia to achieve this but do not operate acutely you will end up excising too
much tissue and can cause anal stenosis recently hyaluronic acid has also been used successfully
next rectal prolapse rectal prolapse is more common in elderly women the classic
question is that there are concentric folds that differentiate rectal prolapse from the linear
folds in a prolapsing hemorrhoid rectal prolapse is treated in a good surgical candidate by trans
abdominal rectopexy and possible sigmoid resection if there is an element of chronic constipation
or an elongated sigmoid that can be a point of argument though in a poor operative candidate
an old frail person say these are where you talk about the altmeier or the delorme procedure these
are basically resection of the prolapse rectum from the perineum in an altmeier you do a true
colo-anal hand sewn anastomosis in a delorme you do a mucosal resection with a muscular plication
anal abscesses and fistula in ano are common questions and are common referrals to general
surgeons it is thought that they start by bacteria getting into anal crypts near the dentate line
so sometimes abscesses once they are drained can continue to drain which suggests a fistula in ano
know the types of abscesses in relationship to the sphincter muscles and the levator muscles
if an abscess above the levators then it is a supra-levator abscess
if it is between the internal and external anal sphincters then it is a intersphincteric
abscess if it is outside of the external anal sphincter then it is a ischiorectal abscess
and if it's just under the skin or mucosa then it is a simple subcutaneous perianal abscess
classification of fistula in ano again depends on the sphincter muscles suprasphincteric is
above the sphincters transsphincteric traverses right through the sphincters
intersphincteric runs between the internal and external sphincters
submucosal doesn't go past the muscle at all the internal opening of the fistula can
be found using goodsal's rule anterior ones take a straight line to the internal opening
posterior to the midline take a curved path ending up with the posterior midline internal opening
goodsal's rule does not work if the external opening is more than two centimeters from the
anal verge submucosal and intersphincteric and low transphincteric can be simply opened up
to treat the fistula suprasphincteric and high transphincteric you do not want to cut too much
muscle which could cause incontinence so then you use things like non-cutting setons
which are placed for six weeks followed by curette of the track or perhaps a mucosal advancement flap
with ligation of the tract a cutting seton is no longer used
due to high risk of incontinence and how painful they are
anal fissures are painful and related to constipation anal fissures are a common
source of rectal bleeding in children they are usually in the posterior midline they
can have a sentinel pile which is basically a skin tag near the external extent of it
lateral anal fissures make you think of crohn's disease or hiv in adults if anal
fissure is acute is acutely onset then treat it conservatively with stool softeners and sits baths
once it has been present for longer than six weeks and resistant to conservative measures
then you may have to do something about it some talk about how botox injection
works but the classic surgery is the lateral internal sphincterotomy this is done by palpating
the intersphincteric groove laterally you place an 11 blade between the internal external sphincter
muscles then you turn the blade medially to cut the internal anal sphincter and spare the mucosa
anal cancer refers to squamous cell cancer of the anal canal the lining of the rectum is
glandular mucosa which makes adenocarcinoma then at the dentate line you transition to
non-keratinized squamous cells which lines the anal canal then at the edge of the anal margin
you transition again to keratinized hair bearing squamous cells squamous cell carcinoma of the
anal canal is related to hpv is so it's probably a good idea to screen women for cervical cancer also
if they have this squamous cell carcinoma of the anal canal is usually treated with chemo radiation
with something called the nigro protocol which is 5fu mitomycin c and 4500 centigrade radiation
since the anal canal commonly drains to the inguinal lymph nodes feel those for cancer
and also the radiation usually includes these nodes bilaterally prophylactically
if the anal squamous cell cancer comes back after chemo radiation
then you would need to do a salvage apr surgery and consider a muscle flap to the perineum
anal melanoma can sometimes be mistaken for external hemorrhoids and can be
amelanotic and fleshy colored if you find one of these local excision is better than apr surgery
apr does not show improved survival be sure to use a pet scan on the patient and
consider a sentinel lymph node biopsy as the inguinal node spread is common
anal margin cancer is basically outside of the anal canal
instead of chemo radiation it is usually treated with surgical excision if it is too big for
surgery or recurs then chemo radiation could be good for anal margin squamous cell carcinoma
extra mammary paget's disease is adenocarcinoma in situ of the perianal skin
bowen's disease is squamous cell carcinoma and situ of the perianal skin pabst
blue ribbon is a mnemonic for that p a b s t buschkie lowenstein tumor is a giant anal
condyloma associated with hpv surgery chemo and radiation may all be needed to treat one of these
and with that i think we will wrap it up i hope that helped good luck
thank you