1. Department of Neurological Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
2. Department of Neurosurgery, The Leon Wiltse Memorial Hospital, Anyang, Gyeonggi-Do, Republic of Korea
3. Department of Neurological Surgery, Dongtan Sacred Heart Hospital, College of Medicine, Hallym University, Hwaseong, Gyeonggi-Do, Republic of Korea