Several biomaterials have been proposed to treat anal fistula alone or in combination with other surgical procedures aiming to reduce recurrence rates while minimizing continence impairment. More recently a porcine dermal matrix injection has been proposed as infill biomaterial to treat fistulae. We propose an approach consisting of non-cutting seton positioning followed several weeks later by flap repair associated with dermal matrix injection into the fistula tracts. We report our experience with this two-staged procedure on 24 consecutive patients with complex anal fistulae with a median follow up of > 12 months. In our experience this two-stage approach seems to be safe and effective.