1. Department of Otorhinolaryngology, Maternal and Child Health Hospital of Tai'an, Tai'an, Shandong 271000, P.R. China
2. Department of Otolaryngology, Affiliated Hospital of Taishan Medical University, Tai'an, Shandong 271000, P.R. China
3. Department of Otolaryngology, Shandong University of Traditional Chinese Medicine, Jinan, Shandong 250011, P.R. China
4. Department of Otolaryngology, Qianfoshan Hospital Affiliated to Shandong University, Jinan, Shandong 250014, P.R. China