1. Department of Surgery, Valencia University Medical School, Valencia, Spain
2. Centre Hospitalaire Regional Universitaire Bellevue, St Etienne, France
3. Centre Hospitalaire Universitaire Vesale, Montigny-le-Tilleul, Belgium
4. University Clinic Hospital, Lisbon, Portugal
5. University Hospital, Coimbra, Portugal
6. Clinique de la Jomayere, St Etienne, France
7. Hospital La Fé, Valencia, Spain
8. Clinique Saint Joseph, Valence, France