Yong Bai1,2, XueZhong Li1, ZhaoFu Yin2. 1. Department of Otolaryngology-Head and Neck Surgery, Key Laboratory of Otorhinolaryngology of Health Ministry, Qilu Hospital of Shandong University, Shandong, China. 2. Department of Otolaryngology-Head and Neck Surgery, Zibo City Central Hospital, Shandong, China.