1 Proctology Unit, Division of Visceral Surgery, Department of Surgery, Geneva University Hospitals and Medical School, 4 Rue Gabrielle-Perret-Gentil, 1211, Geneva 14, Switzerland. frederic.ris@hcuge.ch.
2 Proctology Unit, Division of Visceral Surgery, Department of Surgery, Geneva University Hospitals and Medical School, 4 Rue Gabrielle-Perret-Gentil, 1211, Geneva 14, Switzerland.
3 Department of Surgery, Nyon District General Hospital, Nyon (GHOL), Switzerland.