1. Dept. of Surgical Science. University 'Federico II', Naples, Italy
2. Dept. of Obstetrics and Gynecology, 'San Camillo' Hospital, Trento, Italy
3. Dept. of General Surgery, 'San Polo' Hospital, Monfalcone (Gorizia), Italy
4. Dept. of General and Mini-invasive Surgery, 'San Camillo' Hospital, Trento, Italy