1. Department of General Surgery, Yan'an Hospital Affiliated to Kunming Medical University, Kunming, Yunnan 650051, P.R. China
2. The First School of Clinical Medicine, Yunnan University of Chinese Medicine, Kunming, Yunnan 650051, P.R. China
3. Department of General Surgery, Yan'an Hospital Affiliated to Kunming Medical University, Kunming, Yunnan 650051, P.R. China