1. Otolaryngology-Head and Neck Surgery Department; University Hospital of Modena; Modena
2. Neurosurgery Department; New Civil Hospital Sant'Agostino-Estense; Baggiovara Italy
3. Otolaryngology-Head and Neck Surgery Department; University Hospital of Verona; Verona
4. Neuroradiology Department; New Civil Hospital Sant'Agostino-Estense; Baggiovara Italy
5. Department of Otorhinolaryngology; Head and Neck Surgery, Inselspital, University Hospital and University of Bern; Bern Switzerland