[1] Catholic Univ Korea, Seoul St Marys Hosp, Dept Neurosurg, Seoul, South Korea
[2] Chinese Peoples Liberat Army, Hosp 301, Gen Hosp, Dept Orthopaed Surg, Beijing, Peoples R China
[3] Queen Savang Vadhana Mem Hosp, Dept Orthopaed, Spine Unit, Sriracha, Chonburi, Thailand
[4] Daejeon Woori Spine Hosp, Dept Neurosurg, Daejeon, South Korea
[5] Leon Wiltse Mem Hosp, Spine Ctr, Dept Neurosurg, Suwon, South Korea
[6] Yonsei Univ, Coll Med, Gangnam Severance Hosp, Dept Neurosurg, Seoul, South Korea