title: Biomechanical comparison of cervical fixation via transarticular facet screws without rods versus lateral mass screws with rods.
abstract: OBJECTIVE
  Transarticular facet screws restore biomechanical stability to the cervical spine when posterior cervical anatomy has been compromised. This study compares the more recent, less invasive, and briefer transarticular facet screw system without rods with the lateral mass screw system with rods.
  
  
  METHODS
  For this study, 6 human cervical spines were obtained from cadavers. Transarticular facet screws without rods were inserted bilaterally into the inferior articular facets at the C5-C6 and C5-C6-C7 levels. Lateral mass screws with rods were inserted bilaterally at the same levels using Magerl's technique. All specimens underwent range of motion (ROM) testing by a material testing machine for flexion, extension, lateral bending, and axial rotation.
  
  
  RESULTS
  Both fixation methods, transarticular facet screws without rods and lateral mass screws with rods, reduced all ROM measurements and increased spinal stiffness. No statistically significant differences between the 2 stabilization methods were found in ROM measurements for 1-level insertions. However, in 2-level insertions, ROM for the nonrod transarticular facet screw group was significantly increased for flexion-extension and lateral bending.
  
  
  CONCLUSIONS
  Transarticular facet screws without rods and lateral mass screws with rods had similar biomechanical stability in single-level insertions. For 2-level insertions, transarticular facet screws without rods are a valid option in cervical spine repair.
authors.affiliation: Department of Neurosurgery, Spine and Spinal Cord Institute, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Seong
authors.initials: S
authors.lastname: Yi
authors.affiliation: Department of Neurosurgery, Stanford University Medical Center, Stanford, California, USA.
authors.forename: Dae-Cheol
authors.initials: DC
authors.lastname: Rim
authors.affiliation: Department of Neurosurgery, Stanford University Medical Center, Stanford, California, USA.
authors.forename: Ki-Se
authors.initials: KS
authors.lastname: Nam
authors.affiliation: Department of Neurosurgery, Stanford University Medical Center, Stanford, California, USA.
authors.forename: Sang-Hyun
authors.initials: SH
authors.lastname: Keem
authors.affiliation: Department of Neurosurgery, Stanford University Medical Center, Stanford, California, USA.
authors.forename: Judith A
authors.initials: JA
authors.lastname: Murovic
authors.affiliation: Department of Neurosurgery, Stanford University Medical Center, Stanford, California, USA.
authors.forename: Jesse
authors.initials: J
authors.lastname: Lim
authors.affiliation: Department of Neurosurgery, Stanford University Medical Center, Stanford, California, USA. Electronic address: jonpark1@stanford.edu.
authors.forename: Jon
authors.initials: J
authors.lastname: Park
mesh_terms: D000368:Aged; D001696:Biomechanical Phenomena; D001863:Bone Screws; D002102:Cadaver; D002574:Cervical Vertebrae / Q000601:surgery*; D005260:Female; D005593:Fracture Fixation, Internal / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012399:Rotation; D021801:Zygapophyseal Joint / Q000601:surgery*
keywords: Biomechanical stability; Cadaver; Cervical spine; Lateral mass screw; Material testing machine; Rod fixation; Transarticular facet screw