1 General and Digestive Surgery Department, Hospital de Medina del Campo, Carretera de Peñaranda, 24, 47400 Medina del Campo, Spain. Electronic address: juanragomez@msn.com.
2 General and Digestive Surgery Department, Hospital Quirón-salud Sagrado Corazón, C. Rafael Salgado, 3, 41013 Sevilla, Spain.
3 General and Digestive Surgery Department, Hospital Quirón-salud Sagrado Corazón, C. Rafael Salgado, 3, 41013 Sevilla, Spain; General and Digestive Surgery Department, Hospital Comarcal de Ríotinto, Avda. La Esquila nº 5, 21660 Minas de Ríotinto, Spain.
4 General and Digestive Surgery Department, Hospital Quirón-salud Sagrado Corazón, C. Rafael Salgado, 3, 41013 Sevilla, Spain; General and Digestive Surgery Department, University Hospital Virgen Macarena, Avda. Dr. Fedriani, 3, 41009 Sevilla, Spain.