1. Department of Neurosurgery, Spine Center, The Leon Wiltse Memorial Hospital, Suwon 16480, Republic of Korea
2. Department of Neurosurgery, CHA Bundang Medical Center, CHA University, Seongnam-si 13496, Republic of Korea
3. Department of Neurosurgery, Kyung Hee University, Seoul 02447, Republic of Korea
4. Department of Radiology, CHA Bundang Medical Center, CHA University, Seongnam-si 13496, Republic of Korea