1 Medical College, School of Clinical Medicine, Jining Medical University, Jining, Shandong, China; Department of Gastrointestinal Surgery, Jining No. 1 People's Hospital, Jining, Shandong, China.
2 Department of Gastrointestinal Surgery, Jining No. 1 People's Hospital, Jining, Shandong, China.
3 Department of Gastrointestinal Surgery, Jining No. 1 People's Hospital, Jining, Shandong, China. Electronic address: kongy0537@gmail.com.