Department of Otolaryngology, Chung Shan Medical University Hospital, Taichung 402, Taiwan;
Institute of Medicine, Chung Shan Medical University, Taichung 402, Taiwan;
Department of Otolaryngology, Chung Shan Medical University Hospital, Taichung 402, Taiwan;
Institute of Medicine, Chung Shan Medical University, Taichung 402, Taiwan;