Prof. AMSM Sharfuzzaman
Professor of Surgery
Sir Salimullah Medical College
Tuesday, January 8, 2013 DR. RUBEL, SSMC 1
Anatomic divisions of the large intestine:
3. Anal canal
Layers of the colon and rectum:
3. Inner circular muscle – Coalesces distally to create
the internal anal sphincter.
4. Outer longitudinal muscle – Separated into three
teniae coli in the colon; teniae converge proximally at the
appendix and distally at the rectum.
5. Serosa – Covers the intraperitoneal colon and one
third of the rectum.
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Colorectal and Anorectal Vascular Supply
The arterial supply to the colon is highly variable. In general, the arterial
supply to the colon is as follows:
1. Superior mesenteric artery branches
a. Ileocolic artery (absent in up to 20 percent of people) supplies
blood flow to the terminal ileum and proximal ascending colon.
b. Right colic artery supplies the ascending colon.
c. Middle colic artery supplies the transverse colon.
2. Inferior mesenteric artery branches
a. Left colic artery supplies the descending colon.
b. Sigmoidal branches supply the sigmoid colon.
c. Superior rectal artery supplies the proximal rectum.
The terminal branches of each artery form anastomoses with the
terminal branches of the adjacent artery and communicate via the
marginal artery of Drummond (complete in only 15–20 percent of
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Colorectal and Anorectal Vascular Supply-contd.
3. Internal iliac artery branches
a. Middle rectal artery (variable presence and size).
b. Internal pudendal artery branch.
i. Inferior rectal artery supplies the lower rectum
and anal canal.
A rich network of collaterals connects the terminal
arterioles of each of these arteries, thus making the rectum
relatively resistant to ischemia.
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Except for the inferior mesenteric vein, the veins of the colon, rectum, and
anus parallel their corresponding arteries and bear the same terminology.
The inferior mesenteric vein ascends in the retroperitoneal plane over the
psoas muscle and continues posterior to the pancreas to join the splenic
vein. The venous drainage of the rectum parallels the arterial supply.
The superior rectal vein drains into the portal system via the
inferior mesenteric vein.
The middle rectal vein drains into the internal iliac vein.
The inferior rectal vein drains into the internal pudendal vein,
and subsequently into the internal iliac vein.
A submucosal plexus deep to the columns of Morgagni forms the
hemorrhoidal plexus and drains into all three veins.
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Colorectal and Anorectal Lymphatic Drainage
The lymphatic drainage of the colon originates in a network of
lymphatics in the muscularis mucosa.Lymphatic vessels and lymph
nodes followthe regional arteries.
Lymphatic channels in the upper and middle rectum drain
superiorly into the inferior mesenteric lymph nodes.
Lymphatic channels in the lower rectum drain both superiorly
into the inferior mesenteric lymph nodes and laterally into the internal
iliac lymph nodes.
The anal canal has a more complex pattern of lymphatic drainage.
Proximal to the dentate line, lymph drains into both the inferior
mesenteric lymph nodes and the internal iliac lymph nodes.
Distal to the dentate line, lymph primarily drains into the inguinal
lymph nodes, but also can drain into the inferior mesenteric
lymph nodes and internal iliac lymph nodes
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Colorectal and Anorectal Nerve Supply
The nerves to the colon and rectum parallel the course of the arteries.
1. Sympathetic (inhibitory) arise from T6-T12 and L1-L3.
2. Parasympathetic (stimulatory) innervation to the right and
transverse colon is from the vagus nerve; parasympathetic nerves
to the left colon arise from sacral nerves S2–S4 to form the nervi
The external anal sphincter and puborectalis muscles are innervated by
the inferior rectal branch of the internal pudendal nerve. The levator ani
receives innervation from both the internal pudendal nerve and direct
branches of S3–S5.
Sensory innervation to the anal canal is provided by the inferior rectal
branch of the pudendal nerve. Whereas the rectum is relatively insensate,
the anal canal below the dentate line is sensate.
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1. Anoscopy – The anoscope is useful for examination of the anal canal and
can generally allow examination of the distal 6–8 cm of the anus. Anoscopy
can be diagnostic or therapeutic (e.g., sclerotherapy or rubber band ligation
2. Proctoscopy – The rigid proctoscope is useful for examination of the
rectumand distal sigmoid colon and is occasionally used therapeutically
(e.g., polypectomy, electrocoagulation, or detorsion of a sigmoid volvulus).
3. Flexible Sigmoidoscopy and Colonoscopy – Flexible sigmoidoscopy and
colonoscopy provide excellent visualization of the colon and rectum.
Sigmoidoscopes measure 60 cm in length and may allow visualization as
high as the splenic flexure. Partial preparation with enemas is usually
adequate for sigmoidoscopy and most patients can tolerate this procedure
Colonoscopes measure 100–160 cm in length and are capable of examining
the entire colon and terminal ileum. A complete oral bowel preparation
usually is necessary for colonoscopy and the duration and discomfort of the
procedure usually require conscious sedation. Both sigmoidoscopy and
colonoscopy8, 2013 be usedRUBEL, SSMC
diagnostically and therapeutically 15
1. Plain radiograph of the abdomen (supine, upright, and diaphragmatic
views) are useful for detecting free intraabdominal air, bowel gas patterns
suggestive of small or large bowel obstruction, and volvulus.
2. Contrast studies are useful for evaluating obstructive symptoms,
delineating fistulous tracts, and diagnosing small perforations or
anastomotic leaks. Gastrografin is recommended if perforation or leak is
suspected. Doublecontrast barium enema is more sensitive for the detection
of mass lesions greater than 1 cm in diameter.
3. Computed Tomography – Computed tomography (CT) is commonly
employed in the evaluation of patients with abdominal complaints. Its utility
is primarily in the detection of extraluminal disease, such as intraabdominal
abscesses and pericolic inflammation, and in staging colorectal carcinoma.
Extravasation of oral or rectal contrast also may confirm the diagnosis
of perforation or anastomotic leak. Nonspecific findings such as bowel
wall thickening or mesenteric stranding may suggest inflammatory
bowel disease,enteritis/colitis, or ischemia.
A standard CT scan is relatively insensitive for the detection of intraluminal lesions.
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5. Magnetic Resonance Imaging (MRI) – The main use of MRI in
colorectal disorders is in evaluation of pelvic lesions. MRI is more
sensitive than CT for detecting bony involvement or pelvic sidewall
extension of rectal tumors. MRI with an endorectal coil can be helpful
in the detection and delineation of complex fistulas in ano.
6. Positron Emission Tomography (PET) – Positron emission
tomography is used for imaging tissues with high levels of anaerobic
glycolysis, such as malignant tumors. PET has been used as an adjunct
to CT in the staging of colorectal cancer and may prove useful in
discriminating recurrent cancer from fibrosis.
7. Angiography – Angiography is occasionally used for the detection
of brisk bleeding (approximately 0.5–1.0 mL per minute) within the
colon or small bowel. If extravasation of contrast is identified, infusion
of vasopressin or angiographic embolization can be therapeutic.
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8. Endorectal and Endoanal Ultrasound – Endorectal ultrasound is
primarily used to evaluate the depth of invasion of neoplastic lesions in
the rectum. Ultrasound can reliably differentiate most benign polyps
from invasive tumors and can differentiate superficial (T1–T2) from
deeper (T3–T4) tumors.
This modality also can detect enlarged perirectal lymph nodes.
Ultrasound may also prove useful for early detection of local
recurrence after surgery.
Endoanal ultrasound is used to evaluate the layers of the anal
canal. Internal anal sphincter, external anal sphincter, and
puborectalis muscle can be differentiated.
Endoanal ultrasound is particularly useful for detecting
sphincter defects and for outlining complex anal fistulas.
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Hemorrhoids have plagued humankind since time immemorial,
yet many misunderstandings regarding hemorrhoidal complaints
and disease still exist. Many laypersons and physicians do not
understand the anorectal area and the common diseases
associated with it.
Hemorrhoids are cushions of submucosal tissue containing
venules, arterioles, and smooth-muscle fibers that are located in
the anal canal. Three hemorrhoidal cushions are found in the left
lateral, right anterior, and right posterior positions and are
thought to function as part of the continence mechanism.
Because hemorrhoids are a normal part of anorectal anatomy,
treatment is only indicated if they become symptomatic.
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1. External hemorrhoids are located distal to the dentate line and
are covered with anoderm. Thrombosis of an external hemorrhoid may
cause significant pain. Treatment of external hemorrhoids and skin tags are
only indicated for symptomatic relief.
2. Internal hemorrhoids are located proximal to the dentate line
and covered by insensate anorectal mucosa. Internal hemorrhoids may
prolapse or bleed, but rarely become painful unless they develop
thrombosis and necrosis. Internal hemorrhoids are graded according to the
extent of prolapse:
First-degree hemorrhoids—bulge into the anal canal
Second-degree hemorrhoids—prolapse through the anus but
Third-degree hemorrhoids—prolapse through the anal canal
and require manual reduction
Fourth-degree hemorrhoids—prolapse but cannot be reduced
and are at risk for strangulation
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Internal hemorrhoids are grouped into 4 stages, as follows:
Stage I - Internal hemorrhoids that bleed.
Stage II – Internal hemorrhoids that cause bleeding and
prolapse with straining but return to their resting point by
Stage III - Internal hemorrhoids that bleed and prolapse
with straining and require manual effort for replacement
into the anal canal.
Stage IV - Internal hemorrhoids that do not return into the
anal canal and, thus, are constantly outside.
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3. Combined internal and external hemorrhoids straddle
the dentate line and have characteristics of both internal and external
4. Postpartum hemorrhoids result from straining during labor,
which results in edema, thrombosis, and/or strangulation.
5. Rectal varices may result from portal hypertension. Despite the
anastomoses between the portal venous system (middle and upper
hemorrhoidal plexuses) and the systemic venous system (inferior rectal
plexuses), hemorrhoidal disease is no more common in patients with
portal hypertension than in the normal population. Rectal varices,
however, may cause significant hemorrhage.
In general, rectal varices are best treated by lowering portal venous
pressure. Surgical hemorrhoidectomy should be avoided in these patients
because of the risk of massive, difficult-to-control variceal bleeding.
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Medical Therapy (dietary fiber, stool softeners, increased fluid intake, and
avoidance of straining) – appropriate for bleeding first- and second-degree
Rubber Band Ligation, Sclerotherapy, Infrared
photocoagulation, Laser ablation, Carbon dioxide freezing,
Lord dilatation appropriate for bleeding first-, second-, and selected
Excision of Thrombosed External Hemorrhoids. Acutely
thrombosed external hemorrhoids generally cause intense pain and a palpable
perianal mass during the first 24–72 h after thrombosis. The thrombosis can be
effectively treated with an elliptical excision performed in the office under
local anesthesia. Because the clot is usually loculated, simple incision and
drainage israrely effective. After 72 h, the clot begins to resorb, and the pain
resolves spontaneously. Sitz baths and analgesics often are helpful.
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Rubber Band Ligation
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can provide adequate treatment of early internal
hemorrhoids. Cryotherapy and sclerotherapy are
infrequently used today. Most experienced surgeons use 1 or
2 techniques exclusively.
A number of surgical procedures have been described for
elective resection of symptomatic hemorrhoids. All are based
on decreasing blood flow to the hemorrhoidal plexuses and
excising redundant anoderm and mucosa:
1. Closed Submucosal Hemorrhoidectomy
2. Open Hemorrhoidectomy
3. Stapled Hemorrhoidectomy
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Stapled hemorrhoid surgery, or procedure for prolapsing hemorrhoids
(PPH), has recently become prominent. It was first described in 1997-1998.
During PPH, a specially designed circular stapler with smaller staples is
used. The technique involves placing a suture in the mucosa and
submucosal layers circumferentially approximately 3-4 cm above the
dentate line. The stapler is placed and slowly closed around the purse
string. Care is taken to draw excess internal hemorrhoidal tissue into the
stapler. The stapler is fired, resecting the excess tissue and placing a
circular staple line above the dentate line. This results in resection of
excessive internal hemorrhoidal tissue, pexy of the internal hemorrhoidal
tissue left behind and interruption of the blood supply from above.
It can be done as an outpatient, using local anesthesia with intravenous
(IV) sedation. PPH is mainly used to treat internal hemorrhoids not
amenable to conservative and nonoperative therapies.
PPH does not directly affect the external tissue. Reports have described
shrinking of external hemorrhoidal tissue after PPH, probably from
decreased blood flow. PPH combined with judicial excision of occasional
skin tags is also reported, with good results
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Hemorrhoid surgery can usually be performed using local anesthesia
with IV sedation. Regional or general anesthetic techniques are also
used. Routine preoperative workup for these techniques is required.
Simple distal rectal evacuation is required for a clean operative field.
Distal rectal evacuation is best achieved by small-volume saline
Attention to regular and soft bowel movements is important. Bulk
agents (eg, psyllium seed) and oral fluids are important. Bathing in
tubs for comfort and hygiene is part of the routine. Judicious narcotic
administration relieves pain.
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Complications of hemorrhoidectomy
1. Postoperative pain – Pain can be significant following excisional
hemorrhoidectomy, and requires analgesia with oral narcotics,
nonsteroidal antiinflammatory drugs, muscle relaxants, topical analgesics,
and sitz baths.
2. Urinary retention – Urinary retention occurs in 10–50 percent of
patients after hemorrhoidectomy. The risk of urinary retention can be
minimized by limiting intraoperative and perioperative intravenous fluids,
and by providing adequate analgesia.
3. Fecal impaction – Risk of impaction may be decreased bypreoperative
enemas or a limited mechanical bowel preparation, liberal use of laxatives
postoperatively, and adequate pain control.
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Complications of hemorrhoidectomy-contd.
4. Bleeding – Massive hemorrhage can occur after hemorrhoidectomy.
Bleeding may occur in the immediate postoperative period (often in the
recovery room) as a result of inadequate ligation of the vascular pedicle,
and mandates an urgent return to the operating room. Bleeding may also
occur 7–10 days after hemorrhoidectomy when the necrotic mucosa
overlying the vascular pedicle sloughs. Although some of these patients
may be safely observed, others will require an exam under anesthesia to
ligate the bleeding vessel or to oversew the wounds if no specific site of
bleeding is identified.
5. Infection – Infection is uncommon after hemorrhoidectomy; however,
necrotizing soft-tissue infection can occur with devastating
Severe pain, fever, and urinary retention may be early signs of serious
infection. If this is suspected, an emergent examination under anesthesia,
drainage of abscess, and/or debridement of all necrotic tissue are
6. Long-term sequelae
A. incontinence (usually transient)
B. anal stenosis SSMC
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A fissure in ano is a tear in the anoderm distal to the dentate line. Most anal
fissures occur in the posterior midline. Ten to 15 percent occur in the
midline. Less than 1 percent of fissures occur off midline.
Symptoms and Findings:
Characteristic symptoms include tearing pain with defecation and
hematochezia. On physical examination, the fissure can often be seen in the
anoderm by gently separating the buttocks. Patients are often too tender to
tolerate digital rectal examination, anoscopy, or proctoscopy.
•An acute fissure is a superficial tear of the distal anoderm and almost
always heals with medical management.
•Chronic fissures develop ulceration and heaped-up edges with the white
fibers of the internal anal sphincter visible at the base of the ulcer. There is
often an associated external skin tag and/or a hypertrophied anal papilla
internally. These fissures are more challenging to treat and may require
A lateral location of a chronic anal fissure may be evidence of an underlying
disease such as Crohn disease, human immunodeficiency virus, syphilis,
tuberculosis, 2013 leukemia. SSMC
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Therapy focuses on breaking the cycle of pain, spasm, and ischemia:
1. Dietary changes – bulk agents, stool softeners, and warm sitz baths.
2. Topical agents – Lidocaine jelly or other analgesic creams, nitroglycerin
ointment, oral and topical diltiazem, and topical nifedipine (effective in
most acute fissures, but will heal only approximately 50–60 percent of
3. Botulinum toxin – Botulinum toxin causes temporary muscle paralysis
and has been proposed as an alternative to surgical sphincterotomy for
Although there is limited experience with this approach, results
appear to be superior to other medical therapy, and complications
such as incontinence are rare.
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4. Surgical sphincterotomy – Surgical therapy has been recommended
for chronic fissures that have failed medical therapy, and lateral internal
sphincterotomy is the procedure of choice for most surgeons.
Approximately 30 percent of the internal sphincter fibers are divided.
Healing is achieved in more than 95 percent of patients by using this
technique and most patients experience immediate pain relief.
Recurrence is rare (less than 10 percent), but the risk of minor
incontinence ranges from 5–15 percent.
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Anorectal Sepsis and Cryptoglandular Abscess
Infection of an anal gland in the intersphincteric space results in the
of an abscess that enlarges and spreads along one of several planes in the
perianal and perirectal spaces. The anatomy of these spaces influences the
location and spread of infection.
1. Perianal space – surrounds the anus and laterally becomes continuous
the fat of the buttocks
2. Intersphincteric space – separates the internal and external anal
3. Ischiorectal space (ischiorectal fossa) – located lateral and posterior to
the anus and bounded medially by the external sphincter, laterally by the
ischium, superiorly by the levator ani, and inferiorly by the transverse
The two ischiorectal spaces connect posteriorly above the anococcygeal
ligament but below the levator ani muscle, forming the deep postanal space.
4. Supralevator spaces – above the levator ani on either side of the rectum
(communicate posteriorly). SSMC
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Anorectal Sepsis and Cryptoglandular Abscess
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Anorectal Sepsis and Cryptoglandular Abscess
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Pain is the most common presenting complaint. A palpable mass often is
detected by inspection of the perianal area or by digital rectal examination.
Occasionally, patients will present with fever, urinary retention, or life-
threatening sepsis. The diagnosis of a perianal or ischiorectal abscess can
usually be made with physical exam alone.
However, complex or atypical presentations may require imaging studies
(CT or MRI) to fully delineate the anatomy of the abscess.
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Anorectal abscesses should be treated by drainage as soon as the diagnosis is
established. If the diagnosis is in question, an examination under anesthesia is
often the most expeditious way both to confirm the diagnosis and to treat the
problem. Antibiotics are only indicated if there is extensive cellulitis or if the
patient is immunocompromised, has diabetes mellitus, or has valvular heart
Surgical treatment is based in part on the location of the abscess:
Perianal Abscess – painful swelling at the anal verge. Most can be drained
under local anesthesia. Larger, more complicated abscesses may require
drainage in the operating room.
Ischiorectal Abscesses – may become extremely large and may involve one
or both sides, forming a “horseshoe” abscess. Simple ischiorectal abscesses
are drained through an incision in the overlying skin. Horseshoe abscesses
require drainage of the deep postanal space and often require counterincisions
over one or both ischiorectal spaces.
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Drainage of Perianal abscess
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Intersphincteric Abscess – occur in the intersphincteric space and are
notoriously difficult to diagnose. The diagnosis is made based on a high
index of suspicion and usually requires an examination under anesthesia.
Once identified, an intersphincteric abscess can be drained through a
limited, usually posterior, internal sphincterotomy.
Supralevator Abscess – is uncommon and may result from extension of an
intersphincteric or ischiorectal abscess upward, or extension of an
intraperitoneal abscess downward. It is essential to identify the origin of a
supralevator abscess prior to treatment. If the abscess is secondary to an
upward extension of an intersphincteric abscess, it should be drained
through the rectum.
If a supralevator abscess arises from the upward extension of an ischiorectal
abscess, it should be drained through the ischiorectal fossa. If the abscess is
secondary to intraabdominal disease, the primary process requires
and the abscess is drained via the most direct route.
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Fistula in Ano
A fistula-in-ano is a hollow tract lined with granulation tissue connecting a
primary opening inside the anal canal to a secondary opening in the
perianal skin. Secondary tracts may be multiple and from the same primary
Drainage of an anorectal abscess results in cure for about 50 percent of
patients. The remaining 50 percent develop a persistent fistula in ano. The
fistula usually originates in the infected crypt (internal opening) and tracks
to the external opening. The course of the fistula often can be predicted by
the anatomy of the previous abscess.
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Fistula-in-ano is nearly always caused by a previous anorectal abscess.
Anal canal glands situated at the dentate line afford a path for
infecting organisms to reach the intramuscular spaces.
Other fistulae develop secondary to trauma, Crohn disease, anal
fissures, carcinoma, radiation therapy, actinomycoses, tuberculosis,
and chlamydial infections.
The cryptoglandular hypothesis states that an infection begins in the
anal gland and progresses into the muscular wall of the anal
sphincters to cause an anorectal abscess. Following surgical or
spontaneous drainage in the perianal skin, occasionally a granulation
tissue–lined tract is left behind, causing recurrent symptoms.
Multiple series have shown that the formation of a fistula tract
following anorectal abscess occurs in 7-40% of cases.
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Patients often provide a reliable history of previous pain, swelling, and
spontaneous or planned surgical drainage of an anorectal abscess.
Signs and symptoms (in order of prevalence)
Past medical history-particularly in case of complex fistula
Inflammatory bowel disease
Previous radiation therapy for prostate or rectal cancer
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Patients present with persistent drainage from the internal and/or external
openings. In general, fistulas with an external opening anteriorly connect to
the internal opening by a short, radial tract. Fistulas with an external
posteriorly track in a curvilinear fashion to the posterior midline (Goodsall
rule). However, exceptions to this rule often occur.
Fistulas are categorized based on their relationship to the anal sphincter
complex and treatment options are based on these classifications
1. Intersphincteric fistula – tracks through the distal internal sphincter to
an external opening near the anal verge; often treated by fistulotomy
(opening the fistulous tract), curettage, and healing by secondary intention.
2. Trans-sphincteric fistula – results from an ischiorectal abscess and
extends through both the internal and external sphincters. “Horseshoe”
fistulas usually have an internal opening in the posterior midline and extend
anteriorly and laterally to one or both ischiorectal spaces by way of the deep
postanal space. Fistulas that include less than 30 percent of the sphincter
muscles often can be treated by sphincterotomy. High trans-sphincteric
fistulas, which encircle a greater amount of muscle, are more safely treated
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by initial placement of a seton.
3. Suprasphincteric fistula – originates in the intersphincteric plane
and tracks up and around the entire external sphincter and is usually
treated with a seton.
4. Extrasphincteric fistula – originates in the rectal wall and tracks
around both sphincters to exit laterally, usually in the ischiorectal fossa.
Treatment depends on both the anatomy of the fistula and its etiology. In
general, the portion of the fistula outside the sphincter should be opened
and drained. A primary tract at the level of the dentate line also may be
opened if present. Complex fistulas with multiple tracts may require
numerous procedures to control sepsis and facilitate healing. Liberal use
of drains and setons is helpful.
5. Complex, nonhealing fistula – Complex and/or nonhealing fistulas
may result from Crohn disease, malignancy, radiation proctitis, or
unusual infection. Proctoscopy should be performed in all cases of
nonhealing fistulas to assess the health of the rectal mucosa. Biopsies of
the fistula tract should be taken to rule out malignancy.
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The Parks classification system defining the 4 major types of
anorectal fistulas in order of decreasing frequency is as
Type-1: Intermuscular (70%),
Type -2: Trans-sphincteric (23%),
Type-3: Extrasphincteric (5%),
Type-4: Suprasphincteric (2%).
The intersphincteric fistula is found between internal and
external sphincters. The trans-sphincteric fistula extends
through the external sphincter into the ischiorectal fossa. An
extrasphincteric fistula passes from rectum to skin through
the levator ani. Lastly, the suprasphincteric fistula spans
from the intersphincteric plane through the puborectalis
muscle, exiting the skin after traversing the levator ani.
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This involves injection of contrast via the internal opening,
which is followed by anteroposterior, lateral, and oblique x-
ray images to outline the course of the fistula tract. The
accuracy rate is 16-48%.
Help define muscular anatomy differentiating
intersphincteric from trans-sphincteric lesions and can help
to evaluate the rectal wall for any suprasphincteric
extension. The addition of hydrogen peroxide via the
external opening can help outline the fistula tract course.
This may be useful to help delineate missed internal
openings. This modality has not been used widely for
routine clinical fistula evaluation.
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MRI is becoming the study of choice when evaluating complex fistulae.
It has been shown to improve recurrence rates by providing information
on otherwise unknown extensions.
A CT scan is more helpful in the setting of perirectal inflammatory
disease than in the setting of small fistulae because it is better for
delineating fluid pockets that require drainage than for small fistulae .
A barium enema/small bowel series:
This is useful for patients with multiple fistulae or recurrent disease to
help rule out inflammatory bowel disease.
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Examination under anesthesia
An examination of the perineum, digital rectal examination, and anoscopy
are performed after the anesthesia of choice is administered.
This examination is necessary before surgical intervention,
Several techniques have been described to help locate the course of the
fistula and, more importantly, identify the internal opening.
Inject hydrogen peroxide, milk, or dilute methylene blue into the
external opening and watch for egress at the dentate line. In the authors'
experience, methylene blue often obscures the field more than it helps
identify the opening.
Traction (pulling or pushing) on the external opening may also cause a
dimpling or protrusion of the involved crypt.
Insertion of a blunt-tipped crypt probe via the external opening may
help outline the direction of the tract. If it approaches the dentate line
within a few millimeters, a direct extension likely existed. Care should be
taken to not use excessive force and create false passages.
Rigid sigmoidoscopy can be performed at the initial evaluation to help rule
out any associated disease process in the rectum.
Further colonic evaluation is performed only as indicated .
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The goal of treatment of fistula in ano is eradication of sepsis without
sacrificing continence. Because fistulous tracks encircle variable amounts
of the sphincter complex, surgical treatment is dictated by the location of
the internal and external openings and the course of the fistula.
The laying-open technique (fistulotomy) is useful for 85-95% of primary
fistulae (ie, submucosal, intersphincteric, low transsphincteric).
A probe is passed into the tract through the external and internal
openings. The overlying skin, subcutaneous tissue, and internal sphincter
muscle are divided with a knife or electrocautery, thereby opening the
entire fibrous tract.
Curettage is performed to remove granulation tissue in the tract base.
Complete fistulectomy creates larger wounds that take longer to heal and
offers no recurrence advantage over fistulotomy.
Some advocate marsupialization of the edges to improve healing times.
Perform a biopsy on any firm, suggestive tissue.
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A seton is a drain placed through a fistula to maintain drainage and/or
Cutting setons consist of a suture or a rubber band that is placed
through the fistula and intermittently tightened. Tightening the seton
results in fibrosis and gradual division of the sphincter, thus eliminating
the fistula while maintaining continuity of the sphincter.
A noncutting seton is a soft plastic drain (often a vessel loop) placed in
the fistula to maintain drainage. The fistula tract may subsequently be
laid open with less risk of incontinence because scarring prevents
retraction of the sphincter. Alternatively, the seton may be left in place for
Higher fistulas may be treated by an endorectal advancement flap. Fibrin
glue also has been used to treat persistent fistulas with variable results
Tuesday, January 8, 2013 DR. RUBEL, SSMC 63
Outcome and Prognosis
Approximately two thirds of patients with rectal abscesses
treated by incision and drainage or by spontaneous drainage will
develop a chronic anal fistula.
The recurrence rate of anorectal fistulas after fistulotomy,
fistulectomy, or use of a Seton is about 1.5%.
The overall incidence of major fecal incontinence after surgical
management of complex suprasphincteric fistulas is estimated at
Tuesday, January 8, 2013 DR. RUBEL, SSMC 66
Pilonidal disease (cyst, infection) consists of a hair-containing sinus
or abscess occurring in the intergluteal cleft. These ingrown hairs
may then become infected and present acutely as an abscess in the
Anacute abscess should be incised and drained as soon as the
diagnosis is made. Once an acute episode has resolved, recurrence is
Definitive surgical treatment may include:
1. Unroofing the tract, curetting the base, and
marsupializing the wound
2. Small lateral incision and pit excision
3. Flap closure, Z-plasty, advancement flap, or rotational flap
(extensive and/or recurrent pilonidal disease)
Tuesday, January 8, 2013 DR. RUBEL, SSMC 67
Hair in pilonidal sinus
Tuesday, January 8, 2013 DR. RUBEL, SSMC 68
Rectal prolapse (procidentia) is a protrusion of the full thickness of
the rectum through the anus. The proposed causes are colonic
intussusception or a sliding hernia. Essential defects may be poor
rectal support and increased intra-abdominal pressure.
The condition is seen more commonly in the elderly, particularly
those from nursing homes or on psychotropic drugs.
Anatomically, patients with rectal prolapse have deep rectovesical
space (Douglas pouch); lax levator muscles; a weak puborectalis,
with loss of the acute angle it produces between the rectum and
anus by pulling anteriorly; poor fixation of the rectum to the
sacrum posteriorly; and poor support from the lateral ligaments.
Tuesday, January 8, 2013 DR. RUBEL, SSMC 69
The patient complains of the prolapse, rectal bleeding, or
discharge. Prolapse occurs on straining and, early in the
course of the disease, it reduces spontaneously.With time,
the patient has to reduce it manually. As the prolapse
increases, anal sphincter incompetence and incontinence
develop. A situation of full procidentia, where the prolapse
cannot be reduced, may occur.
It is essential that the prolapse be demonstrated. Full
evaluation of the colon is necessary with colonoscopy and
Tuesday, January 8, 2013 DR. RUBEL, SSMC 71
Surgical treatment combines elements of bowel resection and rectal
fixation. The procedures have a success rate of approximately 85% and
1. Anterior resection and suture fixation of the fully mobilized rectum
to the sacrum is appropriate for low-risk patients who have normal anal
2. The Ripstein procedure, in which the rectum is fully mobilized and
anchored to the presacral fascia with a Teflon or Mersilene mesh, may be
useful for low-risk patients with incompetent anal sphincter.
3. The Thiersch loop, used in high-risk elderly patients, is a loop of
stainless steel wire placed subcutaneously around the circumference of
the anus. This procedure can provide effective palliation but may be
complicated by fecal compaction, infection, or erosion of the wire into
Tuesday, January 8, 2013 DR. RUBEL, SSMC 72
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