Perianal Fistula after Ileoanal Pouch in Patients with Ulcerative Colitis: A Review of 475 Patients Operated on at a Major IBD Center

BACKGROUND: Ileoanal pouch anastomosis is the surgical treatment of choice for patients with intractable ulcerative colitis. Perianal disease is a feature that is often present in Crohn's disease and infrequently in ulcerative colitis. OBJECTIVE: The aim of this study is to identify the incidence and factors associated with the development of postoperative perianal fistula in patients undergoing ileoanal pouch anastomosis for ulcerative colitis. DESIGN: A prospectively collected database at the time of surgery with subsequent follow-up was utilized. SETTING: The study was conducted at a high-volume single institution. PATIENTS: We studied a series of 475 consecutive patients with preoperative diagnosis of ulcerative colitis who underwent ileoanal pouch anastomosis. MAIN OUTCOME MEASURES: The incidence of postoperative perianal fistula and the factors correlating with its development were primary outcome measures of the study. RESULTS: The overall number of patients developing perianal fistulas was 44 of 475 (9%). Eleven patients with perianal fistula (25%) required return to ileostomy, of which 7 had pouch excision. Patients who developed a postoperative perianal fistula had a younger age at the onset of disease, had a lower age at index surgery, and were more likely to be subsequently classified as indeterminate colitis or Crohn's disease. Patients developing perianal fistulas were also more likely to develop partial dehiscence or stricture of the ileoanal anastomosis. LIMITATIONS: This study spans nearly 40 years during which the surgical procedure evolved. CONCLUSIONS: Young age at the onset of disease, lower age at surgery, and postoperative diagnosis of Crohn's disease and indeterminate colitis were the factors correlating with perianal fistulas. Delayed healing of the ileoanal anastomosis with partial separation and/or stricture also correlated with the onset of perianal fistulas. The severity of rectal inflammation at the time of surgery or the presence of stapled versus handsewn anastomosis did not correlate with the development of perianal fistulas.