Qingbo Feng1, Jie Yao2, Shichun Lu3. 1. The Second Clinical College of Dalian Medical University, Dalian, Liaoning, China. 2. Department of Hepatobiliary and Pancreatic Surgery, Northern Jiangsu People's Hospital, Clinic Medical College of Yangzhou University, Yangzhou, Jiangsu, China. 3. Department of Thoracic Surgery, Northern Jiangsu People's Hospital, Clinic Medical College of Yangzhou University, Yangzhou, Jiangsu, China.