Biao Wang1, Lequn Shan1, Dingjun Hao2. 1. Department of Spine Surgery, Honghui Hospital, Xi'an Jiaotong University College of Medicine, No. 76 Nanguo Road, Xi'an, 710054, Shaanxi, China. 2. Department of Spine Surgery, Honghui Hospital, Xi'an Jiaotong University College of Medicine, No. 76 Nanguo Road, Xi'an, 710054, Shaanxi, China. dingjunhaowb@163.com.