1. Department of General Surgery, The Second Xiangya Hospital, Central South University, Changsha, China
2. Department of Urology, the Second Hospital of Lanzhou University, Lanzhou, China
3. Department of Gastrointestinal Surgery, Xijing Hospital of Digestive Diseases, Xijing Hospital, Four Military Medical University, Xi'an, Shaanxi, China
4. Evidence-Based Medicine Center, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China