Daniel H. Kim, MD, FAANS, FACS, is Professor, Vivian L. Smith Department of Neurosurgery, McGovern Medical School, UTHealth Houston, Houston, Texas, USA.Gun Choi, MD, PhD, is a Neurosurgeon, Department of Neurosurgery, Pohang Woori Spine Hospital, Pohang-si, Gyeongsangbuk-do, Republic of Korea.Jin-Sung Kim, MD, PhD, is Professor, Department of Neurosurgery, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seocho-gu, Seoul, Republic of Korea.Dae-Jung Choi, MD, PhD, is Chairman, Himnaera Hospital, Dong-gu, Busan, South Korea.Richard G. Fessler, MD, PhD, is Professor, Department of Neurosurgery, Rush University Medical Center, Chicago, Illinois, USA.