1. Department of Neurosurgery, Severance Hospital, Brain Korea 21 Project for Medical Science, Brain Research Institute, Yonsei University College of Medicine, Seoul, Korea.
2. Department of Neurosurgery, Gandong Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Korea.
3. Department of Neurosurgery, Pusan National University Hospital, Busan, Korea.
4. Department of Neurosurgery, Bundang CHA Hospital, CHA University, Seongnam, Korea.