Fistulectomy and primary sphincteroplasty (FIPS) to prevent keyhole deformity in simple anal fistula: a single-center retrospective cohort study.

FIPS avoids the development of keyhole deformity in the majority of patients with simple anal fistula, but is less successful in posterior fistulas. Since FIPS is a very effective, fast and simple procedure, it should be considered a valid alternative for the treatment of every simple anal fistula.