1) Department of GI & HBP surgery, University of Tsukuba, Tsukuba, Japan
2) Department of Cardiovascular Surgery, University of Tsukuba, Tsukuba, Japan
3) Department of Respiratory Surgery, University of Tsukuba, Tsukuba, Japan
4) Department of Endocrine Surgery, University of Tsukuba, Tsukuba, Japan
5) Department of Pediatric Surgery, University of Tsukuba, Tsukuba, Japan
6) Department of Clinical Health Care Management, University of Tsukuba, Tsukuba, Japan

Tatsuya Oda¹⁾, Yuji Hiramatsu²⁾, Yukio Sato³⁾, Hisato Hara⁴⁾, Koji Masumoto⁵⁾, Osamu Shimomura¹⁾, Kazuhiro Takahashi¹⁾, Manami Doi¹⁾, Kinji Furuya¹⁾, Yohei Owada¹⁾, Koichi Ogawa¹⁾, Yusuke Ohara¹⁾, Yoshimasa Akashi¹⁾, Katsuji Hisakura¹⁾, Shinji Hashimoto¹⁾, Tsuyoshi Enomoto¹⁾, Tsuyoshi Satsumae⁶⁾, Tetsuro Wada⁶⁾, Satoru Honma⁶⁾