A 27-year-old woman with no previous medical problems presents 1 day after prolonged vaginal delivery with passage of stool from the vagina. On physical examination, she has a 2-cm rectovaginal fistula approximately 3.5 cm from the anal verge with no sign of infection. She has no significant gastrointestinal history and no family history of gastrointestinal disorders. What is the best next step for this patient?