Axis screw parallel to the sagittal plane versus traditional pedicle screw in the treatment of atlantoaxial fixation: a finite element study - Baifang Zeng; Meng Ding; Lang Li; Chao Wu; Bingwei Qin; Danwei Shen; Jiayan Deng; Xiangyu Wang (BMC Musculoskeletal Disorders, 2024)