1 Department of Pediatric Surgery, Osaka University Graduate School of Medicine, Suita, Japan; Department of Pediatric Surgery, Aizenbashi Hospital, Osaka, Japan.
2 Department of Pediatric Surgery, Kyushu University, Fukuoka, Japan.
3 Department of Pediatric Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
4 Department of Pediatric Surgery, McGovern Medical School at the University of Texas Health Science Center and Children's Memorial Hermann Hospital, Houston, TX, USA.
5 Department of Surgery, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
6 Department of Preventive Medicine and Public Health, Keio University, Tokyo, Japan.
7 Department of Pediatric Surgery, Osaka University Graduate School of Medicine, Suita, Japan.
8 Department of Pediatric Surgery, Osaka Women's and Children's Hospital, Izumi, Japan. Electronic address: usui@wch.opho.jp.
9 Department of Pediatric Surgery, Osaka Women's and Children's Hospital, Izumi, Japan.