1) Pediatric Surgical Datebase Committee, National Clinical Database (NCD) Committee of the Japanese Society of Pediatric Surgeons, Tokyo, Japan
2) Department of Pediatric Surgery, Nara Hospital, Kindai Medical University, Ikoma, Japan
3) Health Policy and Management, Keio Univerisy, Tokyo, Japan

Takeo Yonekura¹⁾²⁾, Noriaki Usui¹⁾, Makoto Komura¹⁾, Jun Fujishiro¹⁾, Keita Terui¹⁾, Akihiro Fujino¹⁾, Shinya Okamoto¹⁾, Hideyuki Sasaki¹⁾, Takashi Sasaki¹⁾, Kan Terawaki¹⁾, Kazuya Ise¹⁾, Norimichi Hirahara³⁾, Hiroaki Miyata³⁾