1. The First Department of General Surgery, Affiliated Hospital of Chengde Medical University, Chengde, Hebei Province, PR China
2. The First Department of Gynecology, Affiliated Hospital of Chengde Medical University, Chengde, Hebei Province, PR China
3. Surgical Operation Department, Affiliated Hospital of Chengde Medical University, Chengde, Hebei Province, PR China.