Fistula-in-ano

Fistula-in-ano

Introduction to Procedure

We know that undergoing any procedure is a scary experience.  We understand the worry and anxiousness that is associated with surgeries and procedures and aim to walk the road to recovery with you every step of the way. We put this information together using the very helpful handbook, ‘Handbook of Surgical Consent” from Rajesh Nair and David J. Holroyd.  We hope that the following information will answer all your questions and help you with the preparation phase for your procedure.

Description of procedure

A fistula–in-ano is an abnormal communication between the anal canal or lower rectum and the perianal skin. They either result primarily as a result of anorectal sepsis or secondary to pathology such as Crohn’s disease, malignancy, hidradenitis, suppurativa, or, rarely tuberculosis. In general, for operations involving fistula-in-ano, it is performed either under local or general anaesthesia with the patient either face down or in the supine position.

Operative techniques

Conventional Fistulotomy

The tract must first be identified and then subsequently “laid-open” (or de-roofed) using cautery and allowed to heal from the inside out.

Fistulectomy

The entire fistulous tract is excised.  It is left open and allowed to heal through secondary intention, closed primarily with sutures, or closed with an advancement flap.  The rectal side of the tract is closed internally.

Seton Suture

If the fistulous tract is high and involves a significant proportion of the sphincter complex, the surgeon may elect to pass a seton suture (which is essentially a thin Silastic tube or non-absorbable suture) through the tract and the two ends tied together outside the body.  There are two types of seton available, the first being a cutting seton which is gradually tightened ever 2 weeks (over an approximate 6 – 8 week period).  This allows for fibrosis to occur and the tract to gradually heal or becomes low enough to be “laid-open”.

If the fistula is deemed to be “high” (i.e. includes a substantial amount of the sphincter complex), fistulotomy is relatively contraindicated, given the high incidence of incontinence

Park is the recognised classification system and defines four different types of fistula-in-ano: intersphincteric, trans-sphincteric, suprasphincteric and extrasphincteric.

Additional procedures that may become necessary
  • Incision and drainage of perianal/anorectal abscess.
  • Packing of wound.
  • Biopsies of fistula tract/rectal mucosa.
Benefits
  • Diagnostic: Confirm the cause of the underlying fistula tract (i.e. Chron’s disease).
  • Therapeutic: Allow for fistula healing, reduce symptoms (pain/bleeding/mucopurulent discharge/incontinence).
Alternative procedures/conservative measures
  • Anal fistula plug, fibrin glue:It should be emphasised, however, that these treatments are associated with a high fistula recurrence rate.
Serious/frequently occurring risks
  • Post-operative pain, bleeding, incontinence, recurrence, delayed healing, need for multiple procedure.
  • Conventional fistulotomy: Recurrence rates range from 1.9% to 12.5% with an incontinence rate ranging from 4.2% to 12.8%.
  • Fistulectomy: Fewer studies are available to contrast fistulectomy, however, one study demonstrated a recurrence rate of 9.5% with an incontinence rate of 14.3%.
  • Seton Suture: Regarding conventional seton suture placement, the recurrence rate is 6.2% with an incontinence rate of 12.5%.
Blood transfusion necessary
  • Group and save: The process of determining the patient’s ABO blood group and screening serum for the presence of antibodies to common red cell antigens that can cause transfusion reactions.
Type of anaesthesia/sedation
  • General anaesthesia.
  • Local.
  • Regional.
Follow-up or need for further procedure
  • Dressing change/pack changes if abscess drained.
  • Routine outpatient review with histopathology results and review of symptoms.
  • Review in outpatient clinic if seton is of-cutting type and has to be tightened.

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