1. Faculty of Medicine and Surgery, University of Enna Kore, 94100 Enna, Italy
2. Department of Medical, Surgical Sciences and Advanced Technologies “GF Ingrassia” ENT Section, University of Catania, 95123 Catania, Italy
3. UT Southwestern Medical Center, Dallas, 75001 TX, USA
4. Department of Anaesthesia and Intensive Care, Univeristy Hospital Policlinico-San Marco, 24046 Catania, Italy