1. Department of Neurosurgery, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Korea.
2. Department of Neurosurgery, Neurovascular Center of New Korea Hospital, Gimpo, Korea.
3. Department of Neurosurgery, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
4. Department of Neurosurgery, Seoul National University College of Medicine, Seoul National University Boramae Hospital, Seoul, Korea.