title: Comparison of two techniques for transarticular screw implantation in the subaxial cervical spine.
abstract: METHODS
  Cross-sectional study.
  
  
  OBJECTIVE
  To compare 2 techniques of transarticular screw placement in the subaxial cervical spine.
  
  
  BACKGROUND
  Transarticular screws have been used as an alternative method to achieve posterior cervical spine stability. According to current studies there are several techniques for the placement of transarticular screws in the subaxial cervical spine; however, there is no study that has compared these techniques.
  
  
  METHODS
  The techniques of transarticular screw placement by Takayasu (group A) and Dalcanto (group B) were used in 8 cervical specimens. The position, number of facet fractures, involvement of the vertebral artery, encroachment of the anterior branches of cervical nerve roots, and instances that failed to go through the facets were observed and analyzed.
  
  
  RESULTS
  Sixty-four screws were implanted, 32 for group A and the same for group B. Although no facet fractures were seen in group A, there were 10 in group B (χ=9.6, P<0.01). Eight screws involved the vertebral artery in group A and 0 in group B (χ=22.3, P<0.001). Eleven anterior branches of lower cervical nerve roots were encroached in group A and 2 in group B (χ=22.0, P<0.001). No screws failed to go through the facets in group B whereas 2 screws failed in group A, resulting in no significant difference (χ=0.52, P>0.05).
  
  
  CONCLUSIONS
  There was a high risk of injury to the vertebral artery and anterior branches of the cervical nerve roots if the screws were too long and Takayasu technique was used. However, more facets were fractured if Dalcanto technique was applied.
authors.affiliation: Department of Orthopaedic Surgery and Radiology, NingBo 6th hospital, NingBo, ZheJiang, People's Republic of China. zhaoliujun555@sina.com.cn
authors.forename: Liujun
authors.initials: L
authors.lastname: Zhao
authors.forename: Rongming
authors.initials: R
authors.lastname: Xu
authors.forename: Jiayong
authors.initials: J
authors.lastname: Liu
authors.forename: Joseph
authors.initials: J
authors.lastname: Konrad
authors.forename: Weihu
authors.initials: W
authors.lastname: Ma
authors.forename: Weiyu
authors.initials: W
authors.lastname: Jiang
authors.forename: Ming
authors.initials: M
authors.lastname: Li
authors.forename: Huajie
authors.initials: H
authors.lastname: Xia
authors.forename: Qun
authors.initials: Q
authors.lastname: Hua
authors.forename: Guoping
authors.initials: G
authors.lastname: Wang
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001863:Bone Screws; D002574:Cervical Vertebrae / Q000601:surgery*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D016268:Internal Fixators; D008297:Male; D008875:Middle Aged; D019637:Orthopedic Procedures / Q000295:instrumentation / Q000379:methods*