Download MBBS Surgery Presentations 2 Anal Canal Surgical Anatomy Pilonidal Sinus Lecture Notes

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fistula In Ano

Dept Of Surgery

? Measures 2 to 4 cm in length

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? longer in men than in women.

? The dentate or pectinate line marks the transition point between

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columnar rectal mucosa and squamous anoderm.

? The 1 to 2 cm of mucosa just proximal to the dentate line shares

histologic characteristics of columnar, cuboidal, and squamous

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epithelium and is referred to as the anal transition zone.

? The dentate line is surrounded by longitudinal mucosal folds, known as

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the columns of Morgagni, into which the anal crypts empty.

? These crypts are the source of cryptoglandular abscesses

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Lining of the anal canal

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Anorectal Anatomy

Arterial

Supply

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Nerve Supply

Inferior rectal

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Sympathetic: Superior

A middle

hypogastric plexus

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rectal A

Parasympathetic:

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Venous drainage

S234 (nerviergentis

Inferior rectal V

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middle rectal V

Pudendal Nerve:
Motor and sensory

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3 hemorrhoidal

complexes
L lateral

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Anal canal

R antero-lateral

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Anal verge

R posterolateral

Lymphatic drainage

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Above dentate: Inf. Mesenteric
Below dentate: internal iliac

Pilonidal sinus

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Pathogenesis:
A sinus tract at natal cleft resulting from:

?

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Blockage of hair fol icle

?

Fol iculitis

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?

Abscess fol owed by sinus formation.

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?

Hair trapping

?

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Foreign body reaction

?

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The sinus tract is cephald

Associated with:

?

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Caucasians

?

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Hirsute

?

Sedentary occupations

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?

Obese

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?

Poor hygeine
Presentation & Treatment

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Acute

abscess

Incision and drainage

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Recurrence: 40%

Chronic

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Pain and

Wide local excision

discharge

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? with primary closure or

? closure by secondary intension

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Recurrence: 8-15%

Perianal Abscess

? Infection originates in the intersphincteric plane, most likely in

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one of the anal glands.

? This may result in

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? simple intersphincteric abscess
? extend vertically either upward
? downwards horizontally
? circumferentially resulting in varied clinical presentations.

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Aetiology & Pathogenesis:
?4-10 glands at dentate line.
?Infection of the cryptglandular epithelium resulting from obstruction of the

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glands.
?Ascending infection into the intersphincteric space and other potential spaces.
?Bacteria implicated:
E.Coli., Enterococci, bacteroides

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Other causes:
?Crohn
?TB
?Carcinoma, Lymphoma and Leukaemia
?Trauma

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?Inflammatory pelvic conditions (appendicitis)
Pathophysiology

Glandular secretion

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Infection &

stasis

suppuration

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Anal crypts

abscess

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obstruction

formation

Clinical presentation

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Abscess

Clinical presentation

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Perianal

?Perianal pain, discharge (pus) and fever

?Tender, fluctuant, erythematous subcutaneous

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lump

Ischio-rectal

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?Chil s, fever, ischiorectal pain

?Indurated, erythematous mss, tender

Intersphincteric ?Rectal pain, chil s and fever, discharge

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Supralevator

?PR tender. Difficult to identify are. EUA needed

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Treatment

? Abscesses should be drained when diagnosed.

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? Simple and superficial abscesses can most often be drained under

local anesthesia

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? Patients who manifest systemic symptoms, immunocompromised

and those with complex, complicated abscesses are best treated

in a hospital setting.

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? An intersphincteric abscess is drained by dividing the internal

sphincter at the level of the abscess

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Incision and drainage of

anorectal abscess

Modification of Hanley's technique for

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incision and drainage of horseshoe abscess
Fistula in Ano

? In anorectal abscess 50% develop a persistent fistula in ano.

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? The fistula usually originates in the infected crypt (internal

opening) and tracks to the external opening, usually the site of

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prior drainage.

The course of the fistula can often be predicted by the anatomy of

the previous abscess.

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? Majority of fistulas are cryptoglandular in origin, trauma, Crohn's

disease, malignancy, radiation, or unusual infections

(tuberculosis, actinomycosis, and chlamydia) may also produce

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fistulas.

? A complex, recurrent, or non healing fistula should raise the

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suspicion of one of these diagnoses.

Diagnosis

? Patients present with persistent drainage from the internal

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and/or external openings.

? An indurated tract is often palpable.
? Goodsall's rule can be used as a guide in determining the

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location of the internal opening

? Fistulas with an external opening anteriorly connect to the

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internal opening by a short, radial tract.

? Fistulas with an external opening posteriorly track in a

curvilinear fashion to the posterior midline.

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Exceptions: Anterior external opening is greater than 3 cm from the

anal margin. Such fistulas usual y track to the posterior midline.

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Goodsall's rule to determine location of internal opening

Fistulas are categorized based upon their relationship to the anal sphincter

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complex and treatment options are based upon these classifications:

? Intersphincteric fistula tracks through the distal internal

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sphincter and intersphincteric space to an external opening near

the anal verge.

? Transsphincteric fistula often results from an ischiorectal

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abscess and extends through both the internal and external

sphincters

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? Suprasphincteric fistula originates in the intersphincteric plane

and tracks up and around the entire external sphincter

? Extrasphincteric fistula originates in the rectal wal and tracks

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around both sphincters to exit lateral y, usual y in the

ischiorectal fossa

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Intersphincteric

Transsphincteric

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Suprasphincteric

Extrasphincteric

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Treatment

? Goal of treatment of fistula in ano is eradication of sepsis

without sacrificing continence

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? The external opening is usually visible as a red elevation of

granulation tissue with or without concurrent drainage.

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? The internal opening may be more difficult to identify.

? Injection of hydrogen peroxide or dilute methylene blue may

be helpful

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? Simple intersphincteric fistulas can often be treated by fistulotomy ,curettage,

and healing by secondary intention.

? Fistulas that include less than 30% of the sphincter muscles can often be

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treated by sphincterotomy without significant risk of major incontinence.

? High transsphincteric and suprasphincteric fistulas are treated by initial

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placement of a seton.

? Extrasphincteric fistulas are rare, and treatment depends upon both the

anatomy of the fistula and its etiology.

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? Complex and/or nonhealing fistulas may result from Crohn's disease,

malignancy, radiation proctitis, or unusual infection.

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? Proctoscopy should be performed in all cases of complex and/or 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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