1. Department of Neurosurgery, College of Medicine, Seoul National University, Seoul, Korea.
2. Department of Pathology, The Armed Forces Capital Hospital, Seongnam, Korea.
3. Department of Neurosurgery, The Armed Forces Capital Hospital, Seongnam, Korea.
4. Department of Neurosurgery, Bucheon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Bucheon, Korea.