1. Department of Neurosurgery, Eulji General Hospital, College of Medicine, Eulji University, Seoul, Korea.
2. Department of Neurosurgery, St. Vincent's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
3. Department of Neurosurgery, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
4. Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul, Korea.