1. Department of Medicine, surgery and neuroscience , University of Siena, ENT Clinic , Siena , Italy
2. Department of Ear, Nose and Throat, San Giovanni Hospital , Rome , Italy
3. Sacred Heart University , ENT Clinic , Rome , Italy
4. Surgical Sciences Department , University of Turin , 2nd ENT Division, Turin , Italy
5. Department of Otorhinolaryngology , University of Foggia , Foggia , Italy
6. Otorhinolaryngology Unit, “Guglielmo da Saliceto” Hospital , Piacenza , Italy
7. Otorhinolaryngology Unit, “V. Fazzi” Hospital, ASL Lecce , Italy
8. Department of Anesthesiology, Surgical and Emergency Sciences, Otolaryngology, Head and Neck Surgery Unit , Second University of Naples , Naples , Italy
9. Department Otorhinolaryngology, “Ascalesi” Hospital , Naples , Italy
10. Department of Otolaryngology, Civil Regional Hospital , Udine , Italy
11. Department of Otorhinolaryngology, P.A. Micone Hospital , ASL n. 3 Genovese, Genoa - Sestri Ponente , Italy
12. Department of Otorhinolaryngology, Madonna del Soccorso Hospital , San Benedetto del Tronto , ASUR Marche, Italy