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Anorectal Disease
Anatomy
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Wall consists of mucosa, submucosa, and
two complete muscle layers, inner circular,
outer longitudinal.
12-15cm in length, reflection is 6-8cm
above anus.
Anatomy
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Upper 1/3 ant/lat covered by peritoneum,
middle 1/3 only anteriorly covered, lower
1/3 completely retroperitoneal.
Anatomy
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The rectum starts where tenia coli coalesce to
form a complete layer of longitudinal muscle at
level of sacral promontory.
Three distinct curves, proximal and distal curve
to the right, middle curves to the left. These folds
are called Valves of Huston. This area is great for
biopsy purposes as they do not contain all layers
so risk of perforation is less.
Anatomy
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Waldeyer’s fascia is a dense connection between
sacrum and rectum at 4th sacral body goes
anteriorly to rectum, covering sacrum and
overlying vessels and nerves.
Dennonviller’s fascia is a retrovesical septum in
men, rectovaginal in women.
Pelvic floor is musculotendinous sheet formed by
the levator ani muscle and is innervated by S4.
Anatomy
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The pubococcygeus, iliococcygeus, and
puborectalis make the levator ani. These are
paired muscles that are intertwined and act as a
unit.
The anal canal starts at pelvic diaphragm and
ends at anal verge. Approximately 4cm long. The
anatomic anal canal extends from anal verge to
dentate line. Surgical anal canal is anal verge to
anorectal ring, the circular upper border of
puborectalis that is palpable by rectal exam. It is
1-1.5 cm from dentate line.
Anatomy
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The anal verge is the junction between anoderm
and perianal skin.
The dentate line is a true mucocutaneous
junction located 1-1.5 cm from anal verge. A 612mm transitional zone exists above the line
where squamous becomes cuboidal, then
columnar.
Anal sphincter mechanism made by internal and
external sphincters.
Anatomy
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The internal sphincter is a specialized
continuation of the circular smooth muscle
layer of the rectum. It is involuntary, and
contracted at rest.
The intersphincteric plane is a fibrous
continuation of the longitudinal smooth
muscle layer of the rectum
Anatomy
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The external sphincter is a voluntary,
striated muscle divided into three u-shaped
loops (subcutaneous, superficial, and deep).
Acts as a single functional unit.
It is a continuation of the levator ani
muscle, specifically of the puborectalis
muscle.
Anatomy
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The puborectalis starts at the pubis and
joins posterior to the rectum. It is normally
contracted, making a 80 degree angulation
of the anorectal junction.
Puborectalis
Anatomy
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The Columns of Morgnani consist of 8-14
longitudinal mucosal folds just above dentate
line and forming the anal crypts at their distal
end. Small glands empty into these crypts. The
ducts of some of these glands penetrate the
internal sphincter, the body of the gland resides in
the intersphincteric plane.
Arterial supply is superior, middle and inferior
rectal arteries (IMA, Int. Iliac, int. pudendal a).
Anatomy
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Venous Drainage empties into portal and
caval systems. Upper and middle rectum
into SRVIMV Portal vein. The lower
rectum and upper anal canal
MRVIIVIVC. The Lower anal
canal drains into the IRV IVC.
Anatomy
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Three submucosal internal hemorrhoidal
plexuses above dentate line; left lateral,
right posterolateral, right anterolateral.
These drain into the superior rectal vein.
Below the dentate line, the external
hemorrhoid veins drain into the pudendal
veins.
Normal Function
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Storage.
Resting pressure is 10mmHg.
Holds 650-1200 of liquid. More than 1500 is
megarectum. Normal 250-750cc formed feces.
External sphincter is 20% of resting pressure and
100% of generated squeeze pressure. Internal
sphincter provides 80% of resting pressure.
Hemorrhoids
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These cushions are thought to act as a plug
to the anal canal, and contribute 15-20% to
the resting pressure of the anal canal. There
are three of these cushions 11,3,7 o'clock.
Hemorrhoids
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Abnormal swelling of the cushions result in
prolapse of the upper anal/lower rectal tissue thru
the anal canal. This causes the symptoms of
hemorrhoids: bleeding, discomfort, pruritis,
prolapse, swelling, pain, discharge.
Bleeding is the most common symptom, pain is
not common, unless a associated fissure is present
(20%), or it’s a thrombosed external.
Classification of internal hemorrhoids.
Classification of Internal
Hemorrhoids
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I- Bleed, but do not prolapse.
II- Spontaneous prolapsing and reducing
with or without bleeding.
III- Prolapsing,that require manual
reduction.
IV- Prolapsed, cannot reduce.
Prolapsed Internal Hemorrhoids
Thrombosed External
Hemorrhoid
Medical Treatment
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90% can be treated with conservative
medical and conservative non-surgical
measures.
Fiber, avoid constipation, diarrhea if
causative.
Lidocaine jelly, HCTcream, NTG cream.
Sclerotherapy, band ligation, infrared
photocoagulation.
Surgical Hemorrhoidectomy
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Intended to restore the anal canal to
normal or nearly normal functional and
anatomical status.
Surgery involves eliminating the vascular
cushions alone or in combination with
relocation of the squamous epithelium.
Open (Milligan-Morgan) and Closed
(Ferguson-Heaton).
Surgical Hemorrhoidectomy
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Excision of all the internal and external
components of the cushions and closure of
the defect primarily.
Prone Jack-Knife position, butt taped apart.
Open Hemorrhoidectomy
Closed Hemorrhoidectomy
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Hill-Ferguson retractor in place, grab
cushion, place suture at apex 4cm above
dentate line, elliptical excision down to
sphincter. Close from ligated pedicle out to
skin.
Complications: urinary retention, bleeding,
stenosis, incontinence, infection.
Closed Hemorrhoidectomy
Hemorrhoidectomy
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Pain is still the major drawback of the
operation.
Circular stapled hemorrhoidectomy. Less
pain. Learning curve. Rectal wall injury,
rectovaginal fistula, death. Widely used
throughout Europe.
Anal Fissures
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Traditionally attributed to constipation and
passage of hard stool.
Only a minority can recall an episode of
this, so multifactorial problem.
Anal Fissures
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Associated with IBD, trauma, diarrhea,
infectious.
Hypertonicity of anal sphincter is thought
to be main problem here.
Anal Fissures
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Studies using anal manometry done,
showed these people had higher resting
pressures. After lateral sphincterotomy,
pressures significantly reduced with fissure
healing. Also studied using NTG paste, and
found same thing, except, the NTG is not
long lasting, and pressure went back up, so
did recurrent fissures.
Anal Fissures
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Ischemia of the anal mucosa is also thought
to be involved, may account for majority
being in the posterior midline. Studies
show the higher the tone, the less blood
flow to the posterior midline. Lateral
sphincterotomy reverses this.
Anal Fissure
Anal Fissures
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SSX are painful BMs with bleeding. Sharp,
stabbing ripping. Signs of chronicity
(>4weeks) is a sentinel skin pile at distal
margin of lesion. Circular fibers of internal
sphincter my be seen at base.
Non-operative treatment excellent for acute
fissures. Fiber, stool softeners, sitz baths,
local anesthetics, Botox, Nitrates.
Anal Fissure
Surgical Treatment of Fissures
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Anal Sphincter Stretch- gradual dilation of anal
canal to accommodate 4 fingers. Can use Parks
retractor, Balloon inflation.
Lateral sphincterotomy- open vs. closed.
Healing rate 98%. Incontinence 12-15% (open).
25% incontinent to flatus regardless of
procedure. Higher rates of satisfaction for closed,
lower rates of incontinence for closed.
Lateral Sphincterotomy (Closed)
Anorectal Abscess
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Causes can be infectious, IBD,
malignancy, TB, FB, trauma. Majority are
in otherwise healthy individuals.
Cryptoglandular origin.
Anorectal Abscess
Anorectal Abscess
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Half of the anal glands originate in the
intersphincteric plane, drain at the level of the
dentate line. Ductal obstruction leads to stasis,
infection, and abscess formation within the
intersphincteric plane. Once an abscess develops,
spreading may occur in multiple directions.
Drainage of the abscess in 2/3 of cases will
eventuate in a chronic fistula in ano.
Anorectal Abscess
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Most common is perianal (43%-58%).
Presentation: 2-3 days of progressive pain,
swelling, fever, tachycardia, sepsis.
Anorectal Abscess
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An ischiorectal abscess usually presents as
a large tender fluctuant mass of the
buttock, but will occasionally demonstrate
only unilateral tenderness and asymmetry
of the buttocks without fluctuance. Needle
aspiration may confirm diagnosis.
Anorectal Abscess
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Patients with intersphincteric or
supralevator abscess are more likely to
present with fever, and may complain of
anal pain, rectal pain, gluteal pain , yet no
obvious abnormality will be found on
exam. A tender mass may be felt on digital
rectal exam, if tolerated.
Management
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Surgical drainage.
A submucosal or intersphincteric abscess
should be drained intrarectally to prevent
the creation of a fistula. A supralevator
abscess may need to be drained by CT
guided drainage or transabdominal
drainage if inaccessible thru the perineum.
Fistula-in-ano
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Abnormal communication between
perianal skin and anal canal or rectal
lumen.
90% of cryptoglandular origin, most are
preceded by surgical or spontaneous
drainage of an abscess.
Fistula in Ano
Classification
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Type I – Intersphincteric (70%)
Type II- Transsphincteric (23%)
Type III- Suprsphincteric (5%)
Type IV- Extrasphincteric (2%)
Exam Under Anesthesia
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Goal is to identify the external, internal
openings, the course of the tract, presence
of secondary connections, presence of
other rectal disease.
Exam Under Anesthesia
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Scope placed in such a way as to view the known
or predicted location of the internal opening. A
curved probe is gently introduced and guided to
the internal opening. Occasionally you can pass it
the other way.
Can place small catheter into external opening
and flush with methelyne blue, peroxide, sterile
milk, or air. Identification successful in 86%.
Goodsall’s Rule
Fistula Management
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Goal is to abolish the primary fistula,
secondary tracts, prevention of fistula
recurrence, preservation of continence.
Fistula Management
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Management depends on the anatomy of the
fistula. If it is apparent that the fistula is simple,
and low, and the location of the internal opening
can be inferred by probing, fistulotomy can be
performed over the probe thru the predicted site
of the internal opening at the dentate line.
The entire tract is opened along its length. This
should be reserved for low intersphinteric
fistulae, which are short, posterior, and in which
the external sphincter is not involved.
Fistula Management
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Fistulotomy should be avoided anteriorly,
especially in women.
Anal fistulae that involve a large portion
of the external sphincter are considered
complex, as are multiple fistulae, IBD
patients, impaired preoperative continence.
These may require use of a seton.
Seton Fistulotomy
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Fistulotomy is accomplished gradually. The
muscle contained in the seton is slowly divided
due to pressure necrosis, with the divided ends
separating only minimally because of the fibrosis
that develops behind the seton.
An elastic seton (vessel loop) is drawn thru the
tract a loosely secured to itself, tighten
sequentially over time. Repeat every two weeks
until division of the muscle is complete.
Rectal Prolapse