1. Department of Neurosurgery, Ajou University College of Medicine, Suwon 16499, Republic of Korea
2. Department of Neurosurgery, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
3. Promedius Inc., Seoul 05609, Republic of Korea
4. Department of Neurosurgery, Hallym University Dongtan Sacred Heart Hospital, Hwaseong-si 18450, Republic of Korea
5. Department of Neurosurgery, Pusan National University Yangsan Hospital, Busan 50612, Republic of Korea
6. Department of Neurosurgery, Bon Hospital, Daejeon 34188, Republic of Korea
7. Department of Neurosurgery, Daegu Catholic University College of Medicine, Daegu 42400, Republic of Korea
8. Department. of Neurosurgery, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, Daegu 41944, Republic of Korea
9. Department of Neurosurgery, Spine and Spinal Cord Institute, Severance Hospital, Yonsei University College of Medicine, Seoul 03722, Republic of Korea