Surgery for Crohn's anal fistulas.

The aim of this study was to analyze the features of Crohn's anal fistulas and to evaluate the efficacy of seton treatment. In 119 patients with Crohn's disease, the incidence of anal fistula was 56% (67/119), with no significant difference in the incidence among patients with ileitis, colitis, and ileocolitis. "Intractable" anal fistulas were found in 17% of patients with ileitis, compared to 64% of those with colitis (P = 0.051) and 68% of those with ileocolitis (P = 0.014). Seton treatment, i.e., non-cutting, long-term seton drainage, was performed for 21 patients (5 with intersphincteric, and 16 with transsphincteric fistulas). In the 16-month follow up, 9 patients required redrainage for recurrent fistulous abscess, mainly because of progressive colorectal disease. Finally, a good result was obtained in 17 of the 21 patients (81%) and no recurrent fistulous abscess developed in the 8 patients in whom all setons were removed. Anal continence was preserved in all the patients. These results indicate that anal fistulas with Crohn's ileitis were cured more easily than those with colitis or ileocolitis, and that seton treatment was effective for intersphincteric fistula with multiple fistula openings and for transphincteric fistulas in patients exhibiting remission of intestinal Crohn's disease.