1. Department of Neurosurgery, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea.
2. Department of Neurosurgery, College of Medicine, Yeungnam University, Daegu, Korea.
3. Department of Neurosurgery, College of Medicine, Dankook University, Cheonan, Korea.
4. Department of Neurosurgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
5. Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.