1 Department of Gastrointestinal Surgery, Medical College and the First Affiliated Hospital of Chengdu Medical College, Chengdu 610500, Sichuan, China.
2 Department of Gastrointestinal Surgery, Medical College and the First Affiliated Hospital of Chengdu Medical College, Chengdu 610500, Sichuan, China. Electronic address: xiaojiangwei2018@163.com.