1. Department of Neurosurgery, CHA Bundang Medical Center, CHA University, 59, Yatap-ro, Bundang-gu, Seongnam-si, Gyeonggi-do 13496, Republic of Korea
2. Department of Biomedical Science, CHA University, Bundang-gu, Seongnam-si, Gyeonggi-do 13488, Republic of Korea
3. Department of Dental Materials, School of Dentistry, Kyung Hee University, Dongdaemun-gu, Seoul 02447, Republic of Korea
4. Department of Neurosurgery, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul 03181, Republic of Korea