Incontinence following sphincter division for treatment of anal fistula

Management of anal fistula poses problems because of competing goals of cure and maintenance of continence. There is increasing recognition of significant rates of incontinence after sphincter-dividing anal surgery. We aimed to determine cure and continence status in a cohort of anal fistula patients managed by both sphincter-dividing and conserving approaches.

Data on fistula, healing and continence status were gathered by patient questionnaire (Cleveland Clinic incontinence questionnaire), telephone interview and chart review. Fistulae were defined as simple (low risk of incontinence) or complex (high risk). Surgery was defined as sphincter conservation and sphincter division. Incontinence was graded by traditional severity scale (minor/major). Fistula healing was defined as absence of acute or chronic sepsis symptoms from surgery to date of last follow-up.

One hundred and twenty-eight patients were evaluated (out of whom 71% were male subjects, age range 17-82, median age 45 years).Fifty-two percent of the fistulae were complex and 48% were simple, of which 51% and 85% underwent sphincter division respectively. Healing rates were higher for sphincter division than conservation (87%vs 73%, P = 0.06). Complex fistulae undergoing sphincter division led to a higher rate of major incontinence (13%) than sphincter conservation (0%) (P = 0.03). For simple fistulae treated by sphincter division, major (5%) and minor incontinence (11%) was not inconsiderable.

Though cure rates are excellent, incontinence rates remain unacceptably high following sphincter division for complex fistulae and are not insignificant even for simple fistulae. More sphincter conservation should be undertaken.