title: Do translaminar facet screws have the same stability as pedicle screws in two-level anterior lumbar interbody fusion? A biomechanical study.
abstract: OBJECTIVE
  To determine whether translaminar facet screws can provide stability     equivalent to pedicle screws in two-level anterior lumbar interbody fusion.
  
  
  METHODS
  We performed a biomechanical study using 12 fresh human     lumbar spines and tested intact spine, stand-alone two-level ALIF and anterior     fusion augmented with pedicle screws or translaminar facet screws under 400N     compressive preloads and 7.5Nm moments in flexion, extension, axial rotation and     lateral bending, and measured the range of motion and the stiffness of operative     level.
  
  
  RESULTS
  We found two-level ALIF had significantly reduced range of     motion, greater stiffness at operative segments in flexion, axial rotation and     lateral bending (p < 0.05), but decreased stiffness and increased range of     motion in extension (p < 0.05), when compared to intact spine. The two     augmented ALIF constructs have significantly reduced range of motion (p <     0.05) and increased stiffness at operative level (p < 0.05), when compared to     intact spine or stand-alone two-level ALIF. There is no significant difference     of range of motion and stiffness at operative level between the two augmented     constructs in all loading directions (p > 0.05).
  
  
  CONCLUSIONS
  Translaminar     facet screws can provide stability equivalent to pedicle screws, and we     recommend translaminar facet screws as perfect alternatives to pedicle screws in     two-level ALIF.
authors.affiliation: Tianjin 4th Centre Hospital, Department of Orthopaedics, Tianjin, China. yingzh2012@163.com
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhan
authors.forename: Ding
authors.initials: D
authors.lastname: Tian
mesh_terms: D001696:Biomechanical Phenomena; D001863:Bone Screws; D006801:Humans; D007593:Joint Instability / Q000473:pathology / Q000601:surgery; D008159:Lumbar Vertebrae / Q000601:surgery*; D013123:Spinal Fusion / Q000295:instrumentation* / Q000379:methods*; D013131:Spine / Q000473:pathology / Q000601:surgery; D021801:Zygapophyseal Joint / Q000601:surgery*