1. School of Medicine, Nankai University, Tianjin, China.
2. Medical School of Chinese PLA, Beijing, China.
3. Department of General Surgery, The First Medical Center, Chinese PLA General Hospital, Beijing, China.
4. Department of General Surgery, Second Affiliated Hospital of Harbin Medical University, Harbin, China.
5. Outpatient Department of Hongshankou, Jingbei Medical District, Chinese PLA General Hospital, Beijing, China.