Perianal abscess

1
Perianal abscess Anal fistulae

• By
• Rajeev Suryavanshi
• Dept of General Surgery.

2
Perianal abscess

• Definition -
• Infection of the soft tissue surrounding the anal
  canal, with formation of discrete abscess cavity.
• Often cavity is associated with fistulous tract.

3
Anorectal anatomy

• Rectum develops from hind gut at 6 weeks
• Anal canal formed at 8 weeks ectoderm.
• Dentate line transition from endo to ecto.
• Rectum has inner circular.
• outer longitudinal.
• Anal canal 4cm, pelvic diaphragm to anal verge.

4
Anatomy

• External Sphincter-
• - U shaped , continuation of levator ani
• - deep segment is continuous with puborectalis
  muscle and forms anorectal ring felt on DRE.
• - striated muscle
• - voluntary control
• - 3 components - sub mucous, superficial and
  deep.

5
Anatomy-

• Internal sphincter-
• - smooth muscle
• - autonomic control
• - extension of circular muscles of rectum.
• - contracted at rest.

6
Anatomy

• 4-8 anal glands drained by respective crypts, at
  dentate line.
• Gland body lies in intersphincteric plane.
• Anal gland function is lubrication.
• Columns of Morgagni
• 8-14 long mucosal fold.

7
Pathophysiology

• Infection starts in crypto glandular epithelium
  lining the anal canal.
• Internal anal sphincter a barrier to infection
  passing from gut to deep perirectal tissue.
• Duct of Anal gland penetrate internal sphincter
  into intersphincteric space.
• Once infection sets in intersphincteric space it
  can spread further.

8
Pathophysiology
9
Frequency

• Common in 3rd and 4th decade of life
• Male gt female (21)
• 30 present with previous episodes.
• Increase incidence during summer and spring.
• Common in infants , poorly understood mechanism ,
  fairly benign and majority settle with simple
  drainage.

10
Etiology

• Abscess initially forms in the intersphincteric
  space and spreads along adjacent potential
  spaces.
• Common organisms-
• E.Coli
• Enterococcus species
• Bacteroides species.

11
Etiology

• Less common causes -
• Crohns Disease.
• Cancer.
• Tuberculosis.
• Trauma.
• Leukemia.
• Lymphoma.

12
Clinical features

• Symptoms-
• Pain Perianal movement ?
• pressure ?
• Pruritis
• Generally unwell.
• Fever
• Chill and rigor.

• Signs-
• Swelling
• Cellulitis
• induration
• Fluctuation
• Subcutaneous mass, near Perianal orifice.
• DRE- fluctuation at times in ischorectal.

13
Classification of Anorectal abscesses

• Perianal 60
• Ischiorectal 20
• Intersphincteric 5
• Supralevator 4
• Submucosal 1

14
Classification

• Perianal pus underneath skin of anal canal, do
  not traverse external sphincter.
• Ischiorectal suppuration traversing external
  sphincter into Ischiorectal space.
• Intersphincteric suppuration between external
  and internal sphincter.
• Horse shoe abscess - uncommon circumferential
  infiltration of pus with in intersphincteric
  space.

15
Investigation Imaging

• No specific test required
• Patients with diabetes , immunosuppresed will
  need lab evaluation.
• Imaging role in only deep seated, Supralevator
  or intersphincteric abscesses.
• CT Scan , MRI or Anal ultrasonography.

16
Management

• Mainly surgical
• Antibiotics in diabetics immunocompromised
  individuals.
• Early drainage is indicated as delay can cause-
• prolong infection
• tissue destruction ?
• chances of sphincter dysfunction ?
• Promote fistula formation.

17
Management

• Perianal abscess - superficial ones can be
  drained in office under L.A
• Incision
• Pus culture sensitivity
• Packing with iodophor gauge.
• Laxative Sitz bath.
• Review follow up 2-3 weeks to see for healing
  fistula formation.

18
Management

• Organism culture is important.
• Abscess with intestinal organisms have a 40
  chance of forming fistula.
• Cultures growing Staphylococcus species Perianal
  skin infection and have no risk of subsequent
  fistula formation.
• 2. Ischiorectal abscess -
• GA
• Cruciate incision over max swelling.

19
Management

• Pus drained and cultured
• Disrupt loculi
• Drain placed.
• 3. Intersphincteric abscess -
• Transverse incision in anal canal below the
  dentate line, posteriorly.
• Abscess opened, leave drain, prevents premature
  closure.

20
Management

• Supralevator abscess -
• Location etiology determines its drainage
  technique.
• Evaluation with CT Scan MRI .
• Abdominal pathology deal with cause
• If extension of Ischiorectal drainage through
  the space indicated.
• Anterior Supralevator are superficial and more
  common in females.- transanal or transvaginal
  approach can be used.

21
Anal fistula- Fistula-in-ano

• Definition -
• Hollow tract, lined with granulation tissue
  connecting a primary opening inside the anal
  canal to a secondary opening in the Perianal
  skin.
• Treatment of fistula-in-ano can be challenging.

22
Fistula-in-ano

• Magnitude of problem-
• Prevalence rate - 8.6 / 100,000 population.
• Male Female 2 1
• Mean age 38 Years.

23
Etiology

• Following Anorectal abscess.
• Other causes
• - Sec. to trauma
• - Crohns disease
• - Anal fissures
• - Carcinoma
• - Radiation therapy
• - Tuberculosis, Actinomycosis.

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Pathophysiology
25
Clinical presentation

• History Recurrent Swelling, Discharge, Pain and
  Surgery for an Abscess.
• Symptoms
• - Perianal discharge - Pain
• - Swelling - Bleeding
• - External opening

26
Clinical presentation

• Past medical history-
• Inflammatory bowel disease.
• Diverticulitis
• Previous pelvic radiation
• Tuberculosis
• Steroids therapy
• HIV infection

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Clinical presentations

• Physical examination -
• Look at entire perineum,
• An open sinus or elevation of granulation
• tissue.
• Discharge may be seen.
• DRE- fibrous cord, or cord beneath the skin.
• Voluntary squeeze pressures sphincter tone
  should be assessed.

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Goodsall rule Perianal fistula

• Transverse line drawn across the anal verge
• Anterior external opening associated with
  straight tract to anal canal or rectum.
• Posterior ext. opening follows curved tract,
  entering posterior midline.
• Exception 3cm

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Park Classification system-

1. Intersphincteric
2. Transsphincteric
3. Suprasphincteric
4. Extrasphincteric

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Fistula-in-ano

• Fistula with probe

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Fistula-in-ano

• A. Intersphincteric -
• Via internal sphincter to intersphincteric space
  then to perineum.
• 70

• B. Transsphincteric -
• Via internal and external sphincter into
  Ischiorectal fossa and then to perineum.
• 25

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Fistula-in-ano

• Transsphincteric fistula.

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Fistula-in-ano

• C. Suprasphincteric
• Via intersphincteric space superiorly to above
  puborectalis muscle into Ischiorectal fossa then
  perineum.
• 5

• D. Extrasphincteric -
• From Perianal skin through levator ani muscles to
  the rectal wall completely outside sphincter
  mechanism.
• lt1

34
Imaging Studies

• Not indicated for routine evaluation
• Performed when external opening is difficult to
  identify, recurrent or multiple fistulae.
• Fistulography-
• - involves injection of contrast via the
  opening and taking images in different planes.
• - 15- 48 accuracy.

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Imaging studies

• 2. Endo Anorectal Ultrasonography -
• - Transducer 7-10 MHz.
• - Installation of H2O2 can help location of
  internal opening .
• - not widely used.
• 3. MRI -
• - Study of choice
• - 80-90 concordance with oper.finding.
• - good for primary course and sec extensions.

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Imaging

• 4. CT Scan
• - Good for perirectal inflammation disease,
  delineating fluid pockets.
• - Needs oral and rectal contrast.
• - poor delineation of muscular anatomy.
• 5. Barium enema / Small bowel series -
• - Useful in multiple fistulae or recurrent
  disease, also to rule out IBD.

37
fistula imaging

• MRI showing intersphincteric fistula anteriorly
• Prm-puborectalis muscle.

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Other investigations

• Anal Manometry-
• Pressure evaluation of sphincter mechanism
  help in some cases -
• - Decreased tone in preop evaluation
• - previous fistulectomy
• - obstetrical trauma
• - high transsphincteric or suprasphincteric
  fistula
• - very elderly patient.
• If decreased, avoid - surgical division of any
  portion of sphincter.

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Diagnostic procedures

• A. E U A-
• Examination of perineum, DRE, anoscopy.
• To look for internal opening techniques-
• - Inject - H2O2, Milk, Dilute methylene blue
• - Traction on external opening may help
• - Probing gently can help.
• B. Proctosigmodoscopy / Colonoscopy-
• Rigid sigmoidoscopy to rule rectal disease.

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Management

• 1. Fistulotomy / Fistulectomy -
• - laying open technique is useful in 85-95 of
  primary fistulae.
• - overlying skin, subcutaneous tissue,
  internal sphincter divided with electrocautry,
  curette tract to remove granulation tissue.
• - complete fistulectomy creates bigger wound
  with no advantage in minimizing recurrence.
• - perform biopsy of firm or suggestive tissue.

41
Management

• 2. Seton Placement
• - Alone, in combination with fistulectomy or as
  a stage procedure-
• Useful in
• Complex fistulae
• Recurrent fistulae after fistulectomy
• Anterior fistulae in females
• Poor preop sphincter pressure.
• Immunosuppresed patients.

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Seton placement-

• Seton defines sphincter muscles
• Promotes - Drainage
• - Fibrosis.
• Material used-
• - Silk suture
• - Silastic vessel markers
• - Rubber bands

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Seton

• Single stage (cutting)
• Passing seton through tract and tightened down
  with separate silk tie.
• Fibrosis above sphincter muscles seen as it cuts
  the muscles.
• Tightened in office over weeks

• 2. Two Stage (draining / fibrosis)
• Pass seton through deep portion of external
  sphincter.
• Seton left loose here.
• When superficial wound is healed , seton bound
  muscle is divided.
• Studies support 2 stage procedure using 0-nylon.

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3.Mucosal Advancement Flap -

• In chronic high fistula , indication same as
  seton.
• Total fistulectomy , removal of primary and
  secondary tract with internal opening
• Rectal mucomuscular flap is raised .
• Internal muscle defect is closed with absorbable
  suture and flap is sewn down over internal
  opening.
• Single stage procedure
• Poor success in Acute infection and Crohns.

45
Follow up

• Sitz bath
• Analgesia
• Stool bulk agents (bran)
• Frequent office visits to ensure healing.
• Healing in 6 weeks.

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Complications

• Early-
• Urinary retention
• Bleeding
• Fecal impaction
• Thrombosed hemorrhoids.

• Delayed -
• Recurrence
• Incontinence stool)
• Anal stenosis
• Delayed wound healing.

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Outcome Prognosis
Following Rate of Recurrence Incontinence of stool
Standard Fistulotomy 0 -18 3 -7
Seton 0 17 0 -17
Mucosal advancement flap 1- 10 6 8
48
Newer Developments

• Biotechnical advances are producing many new
  tissue adhesives.
• - some reports suggest 60 success with 1
  year follow-up ,using fibrin glue in treatment
  of fistula-in-ano.
• - less invasive ? postop morbidity.

49
Newer developments

• Recurrent fistulous disease to rectum and
  perineum with Anorectal sepsis indication for
  surgery
• Recent reports suggest 50-60 response rate with
  infiximab - the monoclonal antibody to TNFa for
  Perianal fistulae.

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Thank you