1. Department of Neurosurgery, Ajou University Hospital, Ajou University School of Medicine, Suwon, Korea.
2. Department of Neurosurgery, Wonju Severance Christian Hospital, Yonsei University Wonju College of Medicine, Wonju, Korea.
3. Department of Pediatrics, Ajou University Hospital, Ajou University School of Medicine, Suwon, Korea.
4. Department of Obstetrics and Gynecology, Ajou University Hospital, Ajou University School of Medicine, Suwon, Korea.