Risk of sphincter damage and anal incontinence after anal dilatation for fissure-in-ano. An endosonographic study.

Follow-up was performed two to six years after anal dilatation for fissure-in-ano in 32 consecutive patients who had not undergone additional anal surgery. All patients were interviewed and asked specifically about impairment of flatus or fecal control and its possible relation to the anal dilatation. Anal dilatation was followed by minor anal incontinence in 12.5 percent of the patients. Anal endosonographic follow-up was accepted by 20 patients, and sphincteric defects were found in 13 (65 percent) of those. Two patients with anal incontinence had internal sphincter defects. Sphincteric defects were also found in 11 of the 18 continent patients who underwent sonography: internal sphincter defects in nine, external sphincter defect in one, and combined defects of both sphincter muscles in one. In conclusion, anal dilatation results in sphincter damage in more than half of patients, but few of them develop anal incontinence.