1. Department of Neurosurgery, Busan Wooridul Spine Hospital, Busan, Korea.
2. Department of Neurosurgery, Spine Health Wooridul Hospital (SHWH) Gangnam, Seoul, Korea.
3. Department of Cardiovascular Surgery, Busan Wooridul Spine Hospital, Busan, Korea.
4. Department of Neurosurgery, Dongrae Wooridul Spine Hospital, Busan, Korea.