1. Institute of Clinical Otorhinolaryngology, University of Naples, Naples, Italy
2. Ear, Nose and Throat Department, ‘Gradenigo’ Hospital, Turin, Italy
3. Ear, Nose and Throat Department, ‘Villa Sofia’ Hospital, Palermo, Italy
4. Ear Nose and Throat Department, Treviso Regional Hospital, Treviso, Italy
5. Ear, Nose and Throat Department, ‘E. Fornaroli’ Hospital, Magenta, Italy
6. Ear, Nose and Throat Department, Lucca Hospital, Lucca, Italy
7. Ear, Nose and Throat Department, Civil Hospital, Lecce, Italy
8. Ear, Nose and Throat Department, ‘Madonna del Soccorso’ Hospital, San Benedetto del Tronto, Italy