Delayed fecal incontinence following surgery for anal fissure

The surgical treatment of chronic anal fissure is basically done by therapeutic controlled damage to the internal anal sphincter. While fecal incontinence is a well-documented early complication of anal fissure surgery, few data are available about delayed incontinence. The aim of the present study was to assess whether surgical treatment of anal fissures may contribute to the development of delayed anal incontinence.

A retrospective review of patients referred to the Pelvic Floor Laboratory for physiological evaluation of anal incontinence between 1992 and 2009. All patients, diagnosed with anal fissures, who underwent anal dilatation or partial lateral internal sphincterotomy and developed incontinence at least 4 years after the surgery were included. Controls were patients with delayed anal incontinence after obstetric injury.

A total of 21 patients with delayed post-anal fissure surgery incontinence (nine women and 12 men) were identified. The mean (SE) age of incontinence onset in this group of patients was 51.5 (±2), which was 8 years younger than the rest of the 363 incontinent patients (p < 0.001). Time from presumed anal sphincter damage to the onset of incontinence was significantly shorter in the group of past anal-fissure-surgery patients compared to post-obstetric trauma patients (mean difference 15 years, p < 0.001). The severity of incontinence was higher in post-obstetric trauma patients.

Fecal incontinence may present as a late complication of anal fissure surgery. Incontinence may be associated with other cofactors accumulating over time or, more likely, anal fissure surgery may accelerate the physiologic age-related weakening of the anal sphincter mechanism. Candidates for anal fissure surgery should be informed regarding this possible outcome.