1 Department of Orthopedics, The Fourth Affiliated Hospital of Nanchang University, Nanchang, China; Department of Neurosurgery, University of California San Francisco, San Francisco, California, United States of America.
2 Department of Neurosurgery, University of California San Francisco, San Francisco, California, United States of America.
3 Department of Neurosurgery, University of California San Francisco, San Francisco, California, United States of America; Department of Orthopedics Inje University Busan Paik Hospital, Busan, Korea.