Three-dimensional finite element analysis of occipitocervical fixation using an anterior occiput-to-axis locking plate system: a pilot study.
BACKGROUND
Although there are many techniques for occipitocervical fixation, there have been no reports regarding occipitocervical fixation via the use of an anterior anatomical locking plate system.


OBJECTIVE
The biomechanics of this new system were analyzed by a three-dimensional finite element to provide a theoretical basis for clinical application.


METHODS
This was a modeling study.


METHODS
We studied a 27-year-old healthy male volunteer in whom cervical disease was excluded via X-ray examination.


METHODS
The states of stress and strain of these two internal fixation devices were analyzed.


METHODS
A three-dimensional finite element model of normal occiput-C2 was established based on the anatomical data from a Chinese population. An unstable model of occipital-cervical region was established by subtracting several unit structures from the normal model. An anterior occiput-to-axis locking titanium plate system was then applied and an anterior occiput-to-axis screw fixation was performed on the unstable model. Limitation of motion was performed on the surface of the fixed model, and physiological loads were imposed on the surface of the skull base.


RESULTS
Under various loads from different directions, the peak values of displacement of the anterior occiput-to-axis locking titanium plate system decreased 15.5%, 12.5%, 14.4%, and 23.7%, respectively, under the loads of flexion, extension, lateral bending, and axial rotation. Compared with the anterior occiput-to-axis screw fixation, the peak values of stress of the anterior occiput-to-axis locking titanium plate system also decreased 3.9%, 2.9%, 9.7%, and 7.2%, respectively, under the loads of flexion, extension, lateral bending, and axial rotation.


CONCLUSIONS
The anterior occiput-to-axis locking titanium plate system proved superior to the anterior occiput-to-axis screw system both in the stress distribution and fixation stability based on finite element analysis. It provides a new clinical option for anterior occipitocervical fixation.
Department of Orthopedics, Wuhan General Hospital of Guangzhou Command, 627 Wuluo Rd, Wuhan 430070, China. Electronic address: wgcaixh@163.com.
Xianhua
X
Cai
Department of Orthopedics, Wuhan General Hospital of Guangzhou Command, 627 Wuluo Rd, Wuhan 430070, China.
Yang
Y
Yu
Department of Orthopedics, Wuhan General Hospital of Guangzhou Command, 627 Wuluo Rd, Wuhan 430070, China.
Zhichao
Z
Liu
Department of Anatomy, Southern Medical University, 1838 N. Guangzhou Ave., Guangzhou 510515, China. Electronic address: zmc@fimmu.com.
Meichao
M
Zhang
Department of Orthopedics, Wuhan General Hospital of Guangzhou Command, 627 Wuluo Rd, Wuhan 430070, China.
Weibing
W
Huang
D000328:Adult; D001368:Axis, Cervical Vertebra / Q000601:surgery*; D001860:Bone Plates; D001863:Bone Screws; D020342:Finite Element Analysis; D006801:Humans; D016268:Internal Fixators; D008297:Male; D008953:Models, Anatomic; D009777:Occipital Bone / Q000601:surgery*; D010865:Pilot Projects; D011187:Posture; D016059:Range of Motion, Articular; D012399:Rotation
Atlanto-occipital joint; Cervical fixation; Finite element analysis; Occipitocervical fusion