Download MBBS (Bachelor of Medicine, Bachelor of Surgery) 1st Year, 2nd Year, 3rd Year and Final year Surgery 2 Anal Canal Surgical Anatomy Pilonidal Sinus PPT-Powerpoint Presentations and lecture notes
Anal Canal ? Surgical anatomy,
Pilonidal sinus, Perianal abscess,
fistula In Ano
Dept Of Surgery
? Measures 2 to 4 cm in length
? longer in men than in women.
? The dentate or pectinate line marks the transition point between
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
epithelium and is referred to as the anal transition zone.
? The dentate line is surrounded by longitudinal mucosal folds, known as
the columns of Morgagni, into which the anal crypts empty.
? These crypts are the source of cryptoglandular abscesses
Lining of the anal canal
Anorectal Anatomy
Arterial
Supply
Nerve Supply
Inferior rectal
Sympathetic: Superior
A middle
hypogastric plexus
rectal A
Parasympathetic:
Venous drainage
S234 (nerviergentis
Inferior rectal V
middle rectal V
Pudendal Nerve:
Motor and sensory
3 hemorrhoidal
complexes
L lateral
Anal canal
R antero-lateral
Anal verge
R posterolateral
Lymphatic drainage
Above dentate: Inf. Mesenteric
Below dentate: internal iliac
Pilonidal sinus
Pathogenesis:
A sinus tract at natal cleft resulting from:
?
Blockage of hair fol icle
?
Fol iculitis
?
Abscess fol owed by sinus formation.
?
Hair trapping
?
Foreign body reaction
?
The sinus tract is cephald
Associated with:
?
Caucasians
?
Hirsute
?
Sedentary occupations
?
Obese
?
Poor hygeine
Presentation & Treatment
Acute
abscess
Incision and drainage
Recurrence: 40%
Chronic
Pain and
Wide local excision
discharge
? with primary closure or
? closure by secondary intension
Recurrence: 8-15%
Perianal Abscess
? Infection originates in the intersphincteric plane, most likely in
one of the anal glands.
? This may result in
? simple intersphincteric abscess
? extend vertically either upward
? downwards horizontally
? circumferentially resulting in varied clinical presentations.
Aetiology & Pathogenesis:
?4-10 glands at dentate line.
?Infection of the cryptglandular epithelium resulting from obstruction of the
glands.
?Ascending infection into the intersphincteric space and other potential spaces.
?Bacteria implicated:
E.Coli., Enterococci, bacteroides
Other causes:
?Crohn
?TB
?Carcinoma, Lymphoma and Leukaemia
?Trauma
?Inflammatory pelvic conditions (appendicitis)
Pathophysiology
Glandular secretion
Infection &
stasis
suppuration
Anal crypts
abscess
obstruction
formation
Clinical presentation
Abscess
Clinical presentation
Perianal
?Perianal pain, discharge (pus) and fever
?Tender, fluctuant, erythematous subcutaneous
lump
Ischio-rectal
?Chil s, fever, ischiorectal pain
?Indurated, erythematous mss, tender
Intersphincteric ?Rectal pain, chil s and fever, discharge
Supralevator
?PR tender. Difficult to identify are. EUA needed
Treatment
? Abscesses should be drained when diagnosed.
? Simple and superficial abscesses can most often be drained under
local anesthesia
? Patients who manifest systemic symptoms, immunocompromised
and those with complex, complicated abscesses are best treated
in a hospital setting.
? An intersphincteric abscess is drained by dividing the internal
sphincter at the level of the abscess
Incision and drainage of
anorectal abscess
Modification of Hanley's technique for
incision and drainage of horseshoe abscess
Fistula in Ano
? In anorectal abscess 50% develop a persistent fistula in ano.
? The fistula usually originates in the infected crypt (internal
opening) and tracks to the external opening, usually the site of
prior drainage.
The course of the fistula can often be predicted by the anatomy of
the previous abscess.
? Majority of fistulas are cryptoglandular in origin, trauma, Crohn's
disease, malignancy, radiation, or unusual infections
(tuberculosis, actinomycosis, and chlamydia) may also produce
fistulas.
? A complex, recurrent, or non healing fistula should raise the
suspicion of one of these diagnoses.
Diagnosis
? Patients present with persistent drainage from the internal
and/or external openings.
? An indurated tract is often palpable.
? Goodsall's rule can be used as a guide in determining the
location of the internal opening
? Fistulas with an external opening anteriorly connect to the
internal opening by a short, radial tract.
? Fistulas with an external opening posteriorly track in a
curvilinear fashion to the posterior midline.
Exceptions: Anterior external opening is greater than 3 cm from the
anal margin. Such fistulas usual y track to the posterior midline.
Goodsall's rule to determine location of internal opening
Fistulas are categorized based upon their relationship to the anal sphincter
complex and treatment options are based upon these classifications:
? Intersphincteric fistula tracks through the distal internal
sphincter and intersphincteric space to an external opening near
the anal verge.
? Transsphincteric fistula often results from an ischiorectal
abscess and extends through both the internal and external
sphincters
? 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
around both sphincters to exit lateral y, usual y in the
ischiorectal fossa
Intersphincteric
Transsphincteric
Suprasphincteric
Extrasphincteric
Treatment
? Goal of treatment of fistula in ano is eradication of sepsis
without sacrificing continence
? The external opening is usually visible as a red elevation of
granulation tissue with or without concurrent drainage.
? The internal opening may be more difficult to identify.
? Injection of hydrogen peroxide or dilute methylene blue may
be helpful
? 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
treated by sphincterotomy without significant risk of major incontinence.
? High transsphincteric and suprasphincteric fistulas are treated by initial
placement of a seton.
? Extrasphincteric fistulas are rare, and treatment depends upon both the
anatomy of the fistula and its etiology.
? Complex and/or nonhealing fistulas may result from Crohn's disease,
malignancy, radiation proctitis, or unusual infection.
? 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.
This post was last modified on 08 April 2022