1 Department of Surgery, Ito Municipal Hospital, 196-1 Oka, Ito, Shizuoka, Japan. hirotada.muramatsu@mirror.ocn.ne.jp.
2 Department of General Surgery, Tokyo Bay Urayasu Ichikawa Medical Center, 3-4-32 Toudaijima, Urayasu, Chiba, Japan. hirotada.muramatsu@mirror.ocn.ne.jp.
3 Department of Surgery, Ito Municipal Hospital, 196-1 Oka, Ito, Shizuoka, Japan.