1. Department of Pediatrics Juntendo University Faculty of Medicine Tokyo Japan
2. The Pediatric Gastrointestinal Endoscopy National Survey Working Group in Japanese Pediatric Endoscopy Research Group Tokyo Japan
3. Department of General Pediatrics and Gastroenterology Miyagi Children's Hospital Sendai Japan
4. Department of Pediatrics Shinshu University School of Medicine Matsumoto Japan
5. Department of Pediatric Surgery Tokyo Women's Medical University Hospital Tokyo Japan
6. Department of Gastrointestinal and Pediatric Surgery Mie University Graduate School of Medicine Tsu Japan