1. Biostatistics and Medical Information Unit, Groupe Hospitalier Pitié–Salpêtrière, Assistance Publique–Hôpitaux de Paris, Paris, France
2. Pierre and Marie Curie Paris 6 University, Er 4 (former EA3974), Modelling in Clinical Research, Pierre and Marie Curie Paris 6 University, Paris, France
3. Digestive Surgery and Transplantation Unit, Groupe Hospitalier Pitié–Salpêtrière, Assistance Publique–Hôpitaux de Paris, Paris, France
4. General and Digestive Surgery Unit, Institut Monsouris, Paris, France
5. Digestive Surgery Unit, Centre Hospitalier Universitaire de Rangueil, Rangueil, France
6. Visceral Surgery and Transplantation Unit, Centre Hospitalier Universitaire de Limoges, Limoges, France
7. General and Digestive Surgery Unit, Centre Hospitalier General de Lomme, Lomme, France
8. General and Digestive Surgery Unit, Hôpital Louis Mourier, Assistance Publique–Hôpitaux de Paris, Paris, France