title: Finite element analysis of posterior cervical fixation.
abstract: BACKGROUND
  Despite largely, used in the past, biomechanical test, to investigate the fixation techniques of subaxial cervical spine, information is lacking about the internal structural response to external loading. It is not yet clear which technique represents the best choice and whether stabilization devices can be efficient and beneficial for three-column injuries (TCI).
  
  
  OBJECTIVE
  The different posterior cervical fixation techniques (pedicle screw PS, lateral mass screw LS, and transarticular screw TS) have respective indications.
  
  
  METHODS
  A detailed, geometrically accurate, nonlinear C3-C7 finite element model (FEM) had been successfully developed and validated. Then three FEMs were reconstructed from different fixation techniques after C4-C6 TCI. A compressive preload of 74N combined with a pure moment of 1.8 Nm in flexion, extension, left-right lateral bending, and left-right axial rotation was applied to the FEMs.
  
  
  RESULTS
  The ROM results showed that there were obvious significant differences when comparing the different fixation techniques. PS and TS techniques can provide better immediate stabilization, compared to LS technique. The stress results showed that the variability of von Mises stress in the TS fixation device was minimum and LS fixation device was maximum. Furthermore, the screws inserted by TS technique had high stress concentration at the middle part of the screws. Screw inserted by PS and LS techniques had higher stress concentration at the actual cap-rod-screw interface.
  
  
  CONCLUSIONS
  The research considers that spinal surgeon should first consider using the TS technique to treat cervical TCI. If PS technique is used, we should eventually prolong the need for external bracing in order to reduce the higher risk of fracture on fixation devices. If LS technique is used, we should add anterior cervical operation for acquire a better immediate stabilization.
authors.affiliation: Department of Orthopaedics, Zhu Jiang Hospital, Southern Medical University, No. 253, Gongye Big Road, 510282 Haizhu District, Guangzhou, People's Republic of China.
authors.forename: Y
authors.initials: Y
authors.lastname: Duan
authors.affiliation: Department of Orthopaedics, Zhu Jiang Hospital, Southern Medical University, No. 253, Gongye Big Road, 510282 Haizhu District, Guangzhou, People's Republic of China.
authors.forename: H H
authors.initials: HH
authors.lastname: Wang
authors.affiliation: Department of Orthopaedics, Zhu Jiang Hospital, Southern Medical University, No. 253, Gongye Big Road, 510282 Haizhu District, Guangzhou, People's Republic of China.
authors.forename: A M
authors.initials: AM
authors.lastname: Jin
authors.affiliation: Department of Orthopaedics, Zhu Jiang Hospital, Southern Medical University, No. 253, Gongye Big Road, 510282 Haizhu District, Guangzhou, People's Republic of China.
authors.forename: L
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Orthopaedics, Zhu Jiang Hospital, Southern Medical University, No. 253, Gongye Big Road, 510282 Haizhu District, Guangzhou, People's Republic of China.
authors.forename: S X
authors.initials: SX
authors.lastname: Min
authors.affiliation: Department of Orthopaedics, Zhu Jiang Hospital, Southern Medical University, No. 253, Gongye Big Road, 510282 Haizhu District, Guangzhou, People's Republic of China.
authors.forename: C L
authors.initials: CL
authors.lastname: Liu
authors.affiliation: Department of Orthopaedics, Zhu Jiang Hospital, Southern Medical University, No. 253, Gongye Big Road, 510282 Haizhu District, Guangzhou, People's Republic of China.
authors.forename: S J
authors.initials: SJ
authors.lastname: Qiu
authors.affiliation: Department of Orthopaedics, Zhu Jiang Hospital, Southern Medical University, No. 253, Gongye Big Road, 510282 Haizhu District, Guangzhou, People's Republic of China. Electronic address: shuxq2012@163.com.
authors.forename: X Q
authors.initials: XQ
authors.lastname: Shu
mesh_terms: D001863:Bone Screws; D002574:Cervical Vertebrae / Q000601:surgery*; D003198:Computer Simulation; D020342:Finite Element Analysis; D005592:Fracture Fixation / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D015233:Models, Statistical; D016059:Range of Motion, Articular; D012399:Rotation
keywords: Finite element model; Posterior cervical fixation technique; Three-column injuries