1. Department of Neurosurgery, Kangwon National University Hospital, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do;
2. Division of Pediatric Neurosurgery, Seoul National University Children's Hospital, Seoul National University College of Medicine, Seoul; and
3. Department of Neurosurgery, The Armed Forces Capital Hospital, Bundang-gu Seongnam-si, Gyeonggi-do, Korea