1. Department of Surgery, Keio University School of Medicine, Tokyo, Japan
2. Department of Surgery, Hiratsuka City Hospital, Kanagawa, Japan
3. Department of Gastrointestinal Surgery, Saitama City Hospital, Saitama, Japan
4. Department of Surgery, Japanese Red Cross Ashikaga Hospital, Tochigi, Japan
5. Department of Surgery, Kawasaki Municipal Hospital, Kawasaki, Kanagawa, Japan