Long-term indwelling seton for complex anal fistulas in Crohn's disease

PURPOSE: This study was designed to review the results of long-term indwelling seton or depezzar catheter in the management of perianal Crohn's disease. METHODS: A retrospective case review from data extracted from a prospective endorectal ultrasound database was performed. All patients underwent an intraoperative endorectal ultrasound to identify the extent of the fistulas and to assess anal wall thickness. Fistulas were classified by Parks' criteria. All patients then underwent insertion of a seton or depezzar catheter under ultrasound guidance. All patients were followed clinically and with endorectal ultrasound by the senior author. Outcome measures included symptom control, number of procedures required, fecal continence, and reduction in anal wall thickness. RESULTS: Twenty-eight patients with 43 complex perianal Crohn's fistulas were identified. Median follow-up was 13 (range, 2-81) months. Twenty-one percent of patients developed recurrent or new perianal symptoms while the seton was in situ. Eleven percent of patients required further surgical intervention. The median anal wall thickness at the time of diagnosis was 18.5 mm reducing to a median of 14 mm after seton insertion and symptom control (P < 0.02). No patient reported a deterioration in fecal continence after seton insertion. In multivariate analysis, patient age (P < 0.005), reduction in anal wall thickness after seton insertion (P < 0.04), and length of follow-up (P < 0.03) were significant predictors of longterm symptom control. CONCLUSIONS: Long-term indwelling seton is an effective management modality for complex perianal Crohn's fistulas, which does not negatively impact fecal continence. Clinical symptoms and course are associated with anal wall thickness as measured by endorectal ultrasound.