1. Pediatric Surgical Unit, Children’s Hospital ‘G. di Cristina’, ARNAS Civico, 90100 Palermo, Italy
2. Pediatric Surgical Unit, Department Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialities, University of Palermo, 90100 Palermo, Italy
3. Pediatric Surgery Division, Women’s and Children’s Health Department, University of Padua, 35100 Padua, Italy