BACKGROUND Perianal fistulas are frequent complications of Crohn's disease. Intravenous infliximab can control perianal disease and promote perianal fistula closure. Perifistular infliximab injections have been proposed for patients who are intolerant or unresponsive to intravenous therapy. The aim of this study was to assess the long-term efficacy of surgical treatment combined with local infliximab therapy. METHODS A prospective cohort study was designed. Twelve patients with Crohn's disease and high/complex transphincteric and intrasphincteric perianal fistulas refractory to other treatment were submitted to core-out fistulectomies, plus perifistular injections of infliximab (20-25 mg in 15-20 ml of 5% glucose) every 4-6 weeks. The main outcome measure was the clinical closure of all perianal fistulas. A 95% confidence interval was calculated for short- and long-term fistula closure rates. RESULTS None of the procedures were associated with local or systemic adverse effects. Four patients did not complete treatment, two because of relapse of intestinal symptoms, which required intravenous infliximab. In one case, treatment with intravenous infliximab was complicated by a hypersensitivity reaction. Eight patients continued treatment until all perianal fistulas were closed and setons were removed (median: 5 sessions). Persistent closure was observed in seven (87.5%, 95% CI: 47.4-99.6) of the eight patients 12 months after completion of treatment and in five (62.5%; 95% CI: 24.5-91.5) of eight at the end of follow-up (range: 19-43 months, median: 35 months). CONCLUSIONS The cohort we examined is small, but fistulectomy combined with repeated perifistular injections of infliximab appears to be safe and may help in fistula healing. However, in most patients, permanent closure of all fistulas is not achieved.