1. Department of Gastrointestinal Surgery, The Sixth Affiliated Hospital of Sun Yat-sen University, 26 Yuancunerheng Road, Guangzhou 510655, Guangdong, PR China
2. Guangdong Institute of Gastroenterology, Guangdong Provincial Key Laboratory of Colorectal & Pelvic Floor Diseases, Supported by National Key Clinical Discipline, Guangzhou 510655, Guangdong, PR China