Yi Yang1, Junfeng Zeng1, MangMang Xu2, Hao Liu3. 1. Department of Orthopedics, West China Hospital, Sichuan University, No.37, GuoXueXiang, Chengdu, 610041, Sichuan Province, China. 2. Department of Neurology, West China Hospital, Sichuan University, Chengdu, China. 3. Department of Orthopedics, West China Hospital, Sichuan University, No.37, GuoXueXiang, Chengdu, 610041, Sichuan Province, China. liuhao6304@hotmail.com.