A finite element modeling of posterior atlantoaxial fixation and biomechanical analysis of C2 intralaminar screw fixation.
BACKGROUND
The objective of this study was to use three-dimensional finite element (FE) models to analyze the stability and the biomechanics of two upper cervical fixation methods: the C2 intralaminar screw method and the C2 pedicle screw method.


METHODS
From computed tomography images, a nonlinear three-dimensional FE model from C0 (occiput) to C3 was developed with anatomic detail. The C2 intralaminar screw and the C2 pedicle screw systems were added to the model, in parallel to establish the interlaminar model and the pedicle model. The two models were operated with all possible states of motion and physiological loads to simulate normal movement.


RESULTS
Both the C2 intralaminar screw method and the C2 pedicle screw method significantly reduced motion compared with the intact model. There were no statistically significant differences between the two methods. The Von Mises stresses of the internal and external laminar walls were similar between the two methods. Stability was also similar.


CONCLUSIONS
The C2 intralaminar screw method can complement but cannot completely replace the C2 pedicle screw method. Clinicians would need to assess and decide which approach to adopt for the best therapeutic effect.
Department of Orthopaedic Surgery, the Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, China.
Xuexiao
X
Ma
Department of Orthopaedic Surgery, the Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, China.
Xianbo
X
Peng
Department of Orthopaedic Surgery, the Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, China.
Hongfei
H
Xiang
Department of Orthopaedic Surgery, the Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, China.
Yan
Y
Zhang
Department of Orthopaedic Surgery, the Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, China.
Guoqing
G
Zhang
Department of Orthopaedic Surgery, the Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, China. Email: bhchen@hotmail.com.
Bohua
B
Chen
D001696:Biomechanical Phenomena; D001863:Bone Screws; D002574:Cervical Vertebrae / Q000601:surgery; D020342:Finite Element Analysis; D006801:Humans; D016059:Range of Motion, Articular