1. 2nd Academic ORL, Head and Neck Surgery Department, Aristotle University of Thessaloniki, Papageorgiou Hospital, Thessaloniki, Greece
2. Department of Pediatric, General Hospital of Veroia, Veroia, Greece
3. 1st Department of ORL, Head and Neck Surgery, National and Kapodistrian University of Athens, Hippokrateio Hospital, Athens, Greece
4. Department of Pathology, Papageorgiou Hospital, Thessaloniki, Greece