1. Department of Orthopedics, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, P.R. China
2. Center for Reproductive Medicine, Shandong University, Jinan, Shandong 250012, P.R. China
3. Department of Otorhinolaryngology, The Second Hospital of Shandong University, Jinan, Shandong 250000, P.R. China