1 Department of Gastrointestinal Surgery, West China Hospital, Sichuan University, Sichuan University West China Hospital, Chengdu, Sichuan, China.
2 West China hospital of Stomatology, Sichuan University, Chengdu, China.
3 Department of Gastrointestinal Surgery, West China Hospital, Sichuan University, Sichuan University West China Hospital, Chengdu, Sichuan, China wxt1@medmail.com.cn.