1. Department of Spine Surgery, Xiangya Hospital of Central South University, Changsha 410008, Hunan Province, China
2. Department of Orthopedic Surgery, Mwananyamala Regional Referral Hospital, P.O. Box 61665, Dar-es-Salaam, Tanzania
3. Department of Orthopedic Surgery, Mount Meru Regional Referral Hospital, P.O. Box 3092, Arusha, Tanzania