From the Department of Otolaryngology, Insular University Hospital of Gran Canaria, Canary Island, Spain
2.From the University Hospital Insular of Gran Canaria the University Hospital "La Fe," Valencia
3.the University Clinic of Navarra
4.and the Otologic Center "Garcia Ibanez," Barcelona spain
5.From the University Hospital Insular of Gran Canaria
6.the University Hospital "La Fe," Valencia