Gang-lei Liu1, Xian-rui Wu2, Bo Shen3. 1. Department of Colorectal Surgery, Cleveland Clinic Foundation, Cleveland, Ohio, USA; Department of Geriatric Surgery, Second Xiangya Hospital, Central South University, Changsha, China. 2. Department of Colorectal Surgery, Cleveland Clinic Foundation, Cleveland, Ohio, USA. 3. Department of Gastroenterology/Hepatology, Cleveland Clinic Foundation, Cleveland, Ohio, USA.