Hyeun-Sung Kim1, Choon-Keun Park2, Choll W Kim3. 1. Department of Neurosurgery, Nanoori Hospital Gangnam, Seoul, South Korea neurospinekim@gmail.com. 2. Department of Neurosurgery, Spine Center, The Leon Wiltse Memorial Hospital, Suwon, South Korea. 3. Excel Spine Center, San Diego, CA, USA.