1. Department of Otorhinolaryngology, Fondazione I.R.C.C.S. Policlinico San Matteo, 27100 Pavia, Italy
2. Neurosurgery Unit, Fondazione I.R.C.C.S. Policlinico San Matteo, 27100 Pavia, Italy
3. Associazione Naso Sano, Umbria Regional Registry of Volunteer Activities and Research, 06121 Perugia, Italy
4. Department of Otorhinolaryngology, University of Pavia, 27100 Pavia, Italy
5. Neurosurgery Unit, Ospedale Moriggia Pelascini, 22015 Gravedona, Italy