1. Department of Otolaryngology - Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan
2. Department of Otolaryngology - Head and Neck Surgery, Kurashiki Central Hospital, Okayama 710-8602, Japan
3. Department of Otolaryngology - Head & Neck Surgery, National Hospital Organization Kyoto Medical Center, Kyoto 612-0861, Japan
4. Department of Otolaryngology - Head & Neck Surgery, Kobe City Medical Center General Hospital, Hyogo 650-0047, Japan
5. Department of Otolaryngology, Japanese Red Cross Otsu Hospital, Shiga 520-0046, Japan
6. Department of Otorhinolaryngology - Head and Neck Surgery, Shiga General Hospital, Shiga 524-8524, Japan
7. Department of Otolaryngology, Tenri Hospital, Nara 632-0015, Japan
8. Department of Head and Neck Surgery, Nara Prefecture General Medical Center, Nara 630-8581, Japan
9. Department of Otolaryngology - Head & Neck Surgery, Hyogo Prefectural Amagasaki General Medical Center, Hyogo 660-8550, Japan