1. Department of Gastrointestinal Surgery, Ageo Central General Hospital, Ageo, Japan.
2. Department of Hepato-Biliary-Pancreatic and Gastrointestinal Surgery, International University of Health and Welfare, Narita Hospital, Narita, Japan.
3. Department of Surgery, Ashikaga Red Cross Hospital, Ashikaga, Japan.
4. Department of Plastic & Reconstructive Surgery, Ageo Central General Hospital, Ageo, Japan.
5. Department of Otorhinolaryngology, Ageo Central General Hospital, Ageo, Japan.
6. Department of Head & Neck Surgery, Ageo Central General Hospital, Ageo, Japan.