Global citimpact: 10.29 Researcher at Dept. of Pediatric Surgery, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655; Dept. of Pediatric Surgery, Graduate School of Medicine, Saitama Medical University, 38 Morohongo, Moroyamacho, Irumagun, Saitama prefecture 350-0495. Electronic address: .