1. Department of Neurosurgery, Seoul National University Bundang Hospital, Seongnam, Korea.
2. Department of Neurosurgery, Seoul National University Hospital, Seoul, Korea.
3. Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea.
4. Seoul National University College of Medicine, Seoul National University, Seoul, Korea.
5. Department of Neurosurgery, Dong-Eui Medical Center, Busan, Korea.
6. Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.