1. Department of Otorhinolaryngology, University of Insubria, Varese, Ospedale di Circolo e Fondazione Macchi, Via Guicciardini 9, 21100 Varese, Italy
2. Department of Otorhinolaryngology, University of Pisa, Pisa, Azienda Ospedaliero Universitaria Pisana, Via Paradisa 2, 56100 Pisa, Italy