1. Department of Gastrointestinal Surgery, Yueyang Central Hospital, Yueyang, People's Republic of China.
2. Department of Anorectal Surgery, Yueyang Central Hospital, Yueyang, People's Republic of China.
3. Department of Gastroenterology, Yueyang Central Hospital, Yueyang, People's Republic of China.
4. Department of Hepatobiliary Surgery, Yueyang Central Hospital, Yueyang, People's Republic of China.