1. Department of Otolaryngology Head and Neck Surgery, Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China
2. Department of Operating Room, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China
3. Department of Otolaryngology, The 940th Hospital of The Joint Logistic Support Force of PLA, Lanzhou, Gansu 730050, P.R. China