Benign Anorectal: Abscess and Fistula by k8o9Om

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									Benign Anorectal: Abscess and
Fistula
Seema Izfar, MD

12/21/11
Benign Anorectal: Abscess and
Fistula


   anorectal abscess and fistula-in-ano represent different stages of the
    same disease

       the abscess represents the acute inflammatory event

       the fistula represents the chronic process
Benign Anorectal: Abscess and
Fistula



   diagnosis and treatment requires in-depth understanding of anorectal
    anatomy and spaces
Benign Anorectal: Abscess and
Fistula

   at the dentate line, the ducts of the anal glands empty into anal crypts

   80% are submucosal, 8% extend to internal sphincter, 8% to the
    conjoined longitudinal muscle, 2% intersphincteric, 1% penetrate
    internal sphincter

   90% of anorectal abscess result from crytogladular infection

   Parks cryptoglandular theory - obstruction of anal glands leads to
    stasis and infection
Abscess

   classified by location: perianal, ischioanal, intersphincteric,
    supralevator

   perianal abscess most common, supralevator most rare

   pain, swelling, fever hallmark symptoms

       supralevator abscess may have gluteal pain

       rectal pain with urinary symptoms - possibly indicate
        intersphincteric or supralevator abscess
Abscess - Etiology

    nonspecific cryptoglandular (90%)

    specific causes:

        inflammatory bowel disease,

        specific infection, ie TB, actinomycosis, lymphogranuloma
         venereum,

        trauma or foreign body

        surgery (episiotomy, hemorrhoidectomy, prostatectomy),

        malignancy - carcinoma, lymphoma, radiation-related
Abscess - Treatment


    exam under anesthesia for pain out of proportion to exam

    incision and drainage - trim edges to prevent coaptation

    I&D of supralevator abscess:

        depends on location - intersphincteric origin then divide internal
         sphincter and drain into rectum; if arises from ischianal abscess
         can be drained through perineal skin
Abscess
Abscess
Abscess - Treatment



    catheter drainage: stab incision to drain pus, mushroom catheter in
     cavity to drain pus

        make stab incision as close as possible to anus

        size and length of catheter should correspond to abscess cavity
Abscess - Treatment

   primary fistulotomy

          may be easier to identify tract

          eliminates source of infection

          decreases recurrence/need for reoperation



   downsides: false passage formation with acute inflammation, 30-50%
    of those with abscess likely won’t develop a fistula, need for
    anesthesia vs. local for I & D
Abscess - Antibiotics




   little or no role except in case of valvular heart disease, prosthetic
    devices, severe cellulitis, diabetes, immunosuppression
Abscess - Complications

   Recurrence

       recurrence in as many as 89% of pts

   Extra-anal causes

       should be evaluated for recurrent disease (hidradenitis suppurativa,
        Crohn’s)

   Incontinence

       iatrogenic (superficial external sphincter), inappropriate wound
        care (excessive scarring from prolonged packing)
Abscess - Complications

   can result in necrotizing anorectal infection (rare)

   resuscitation, IV abx, wide debridement to healthy tissue

   need for colostomy debatable - recommended if sphincter muscle is
    grossly infected, immunocompromised, rectal or colonic
    involvement/perforation

   reexamination under anesthesia

   HBO - 100% O2 at 3atm over 2 hrs - promote leukocyte phagocytic
    function and fibroblast proliferation
Anal Infection and Hematologic
Diseases

   anorectal suppuration with acute leukemia with mortality 45-78%

   neutrophil count <500 with 11% incidence of anorectal abscess

   most important prognostic factor - # days of neutropenia

   presenting symptoms: fever, pain, urinary retention

   antibiotics vs I & D if fluctuance, sepsis, or progression of soft tissue
    infection after antibiotics trial
Anal Infection & HIV


   HIV+ pts have increased risk of perianal sepsis

   can be associated with in situ neoplasia

   surgery + antibiotics 2/2 immunosuppression

       make incison site small bc pts at risk for poor wound healing
Fistula-in-ano

   abnormal communication between any two epithelium-lined surfaces

   Parks classification:
Intersphincteric Fistula-in-ano

   most common type of fistula - 70%

   results from perianal abscess

   variations:

       simple low tract

       high tract with rectal opening or blind tract

       extrarectal extension

       pelvic disease tracking
Transsphincteric Fistula


   approx 23% fistulas

   results from ischioanal absecesses

   rectovaginal fistula is a form of transsphincteric fistula

   operative mgt with setons if sphincter preservation in question
Suprasphincteric Fistula



   5% of fistulas

   result from supralevator abscesses

   tract arises from intersphincteric abscess, travels above puborectalis,
    then downward lateral to external sphincters in ischioanal space
Extrasphincteric Fistula


   2% of fistulas - rarest form

   from rectum above the levators, through them, to the perianal skin

   trauma, foreign body, Crohn’s carcinoma

   most common cause is iatrogenic from probing during fistulotomy
    surgery
Fistula-in-ano: Physical
Examination
   Goodsall’s rule:

       transverse line across the perineum -

       posterior external openings have internal openings in the posterior
        midline

       anterior external openings have tract radially toward the nearest
        crypt

       greater distance from anal margin with more variability

       more accurate rule for posterior fistulas
Fistula-in-ano: Treatment



   eliminate fistula,

   prevent recurrence,

   preserve sphincter function
Fistula-in-ano: Treatment


   identification of internal opening

       passage of probe

       injection of dye, milk, or hydrogen peroxide

       following granulation in fistula tract

       noting puckering of crypt with traction on fistula tract
Fistula-in-ano: Operative
Management



   Lay-open technique: identification of tract with unroofing tract +/-
    marsupialization

   appropriate for simple interspincteric and low transsphincteric
Fistula-in-ano: Operative
Management
   Seton - placement of non-absorbable suture material in fistula tract

   indications for setons:

       promote fibrosis around fistula tract that encircles entire sphincter
        mechanism

       mark the site of fistula in massive anorectal sepsis

       anterior high transsphincteric fistulas in women

       HIV pts with poor wound healing and high transsphincteric fistulas

       Crohn’s

       any time continence is questioned
Fistula-in-ano: Operative
Management


   high-transphincteric fistulas can be treated with combination lay-open
    technique and seton placement - division of internal sphincter to level
    of external opening and then seton placement

   cutting setons can convert high fistulas to low fistulas

   second-stage fistulotomy ~ 8 wks later
Fistula-in-ano: Operative
Management


   suprasphincteric fistula - tract involves external sphincter and
    puborectalis -

       can manage with division of internal sphincter and superficial
        external sphincter with seton around remaining ES

       or internal sphincterotomy, seton, opening of fistula tracts without
        division of external sphincter
Fistula-in-ano: Operative
Management
   Anorectal Advancement Flap

       internal opening closed with absorbable suture, full-thickness flap
        of rectal mucosa/submucosa/IAS raised - adv 1 cm beyond internal
        opening

       base of the flap should be twice the width of the apex

       pros: reduction in healing time, reduced pain, little potential
        damage to sphincters, lack of deformity to anal canal

       poor outcomes in Crohn’s, pts on steroids, smokers, o/w success
        reported in up to 90% of pts
Fistula-in-ano: Operative
Management


   Fibrin Glue - used in conjuntion with AAF or alone

   technique: internal and external openings identified, tract curetted,
    fistula tract injected through connector from external opening until
    glue visible in internal opening, slowly withdrawn

   can be repeated several times without compromising continence
Fistula-in-ano: Operative
Management


   Fibrin Glue - Followup:

   short-term follow-up with good success 70-80%

   longer follow-up with success falling to 60% and even 14% in pts with
    complex anal fistulas
Fistula-in-ano: Operative
Management


   bioprosthetic fistula plug made from surgisis

   technique - identification of internal and external opening with
    placement of plug over probe using suture similar to seton placement

   plug secured at primary opening using absorbable suture
Fistula-in-ano: Operative
Management


   technique works best with long tracts without active inflammation or
    sepsis

   short-term follow up (3months) with higher success rate for Crohn’s
    fistulas when compared to fibrin glue

   long-term follow up - high failure rate
Crohn’s and Anal Fistulas



   the most common perianal manifestation and occur in 6-34% Crohn’s
    pts - pts with colonic Crohn’s with higher incidence, rectal Crohn’s
    with 100% fistula formation

   conservative approach to treatment as 38% heal without surgery
Crohn’s and Anal Fistulas

   medications for treatment: cipro/flagyl, immunomodulators (steroids,
    6MP, azathioprine, infliximab)

   6-MP and azathioprine only effective in 1/3 pts with fistulizing Crohn’s

   Infliximab associated with 62% reduction

   combination 6MP and infliximab may prolong effect of treatment

   selective seton placement with infliximab + maintenance med with
    healing in 67%
Crohn’s and Anal Fistulas



   operative intervention: seton placement, rectal advancement flap if
    rectal-sparing, poss fibrin glue/plug

   avoid cutting sphincter - incontinence reported in pts with Crohn’s
    proctitis even without anal surgery

								
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