1. Third Department of General Surgery, The Central Hospital of Xiangtan, Xiangtan, Hunan 411100, P.R. China
2. Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, D‑30159 Hannover, Germany
3. Scientific Research Department, The Central Hospital of Xiangtan, Xiangtan, Hunan 411100, P.R. China