1. Department of Orthopedic Surgery; East Branch; Sichuan Provincial People's Hospital; Sichuan Academy of Medical Science; 585 North Da Mian Hong He Ave Long Quan District Chengdu 610110 People's Republic of China
2. Department of Spinal Surgery; Nanfang Hospital; Southern Medical University; 1838 North Guangzhou Avenue Guangzhou 510515 People's Republic of China