H L Chulani Consultant Colon and Rectal Surgeon, Lilavati Hospital, Bandra, Mumbai. Risk factors as a cause of recurrence include complex type of fistula, horse-shoe extension, lack of identification or lateral location of the internal fistulous opening, previous fistula surgery and the surgeon performing the procedure. Incontinence is associated with female sex, high anal fistula, type of surgery and previous fistula surgery. The goal of surgical treatment is thus two fold- to eradicate the suppurative process permanently without compromising anal continence. Majority of anal fistula tracts tend to follow these anatomical lines.
Tracts following anatomical lines are generally of non-specific origin.
Crohn's disease, malignancy and lymphogranuloma venereum tend to breach anatomical barriers and may present in a bizarre fashion. However, sometimes these external openings present a various distance from the anal margin and then could present difficulties in diagnosis. Many anteriorly located fistula tracts are often mistaken for urethral fistula and mistakenly incised as a peri-urethral abscess when presenting in an acute form. Fistula openings in the buttock region, lateral aspect of the thigh and even lower into the thigh are not unknown and special attention should be directed to these uncommon presentations and appropriate diagnostic aids used to correctly diagnose them. These are termed incorrectly as 'blind internal' fistula-though the term fistula cannot be applied to them at all.