title: Effect of screw position on load transfer in lumbar pedicle screws: a non-idealized finite element analysis.
abstract: Angled screw insertion has been advocated to enhance fixation strength during posterior spine fixation. Stresses on a pedicle screw and surrounding vertebral bone with different screw angles were studied by finite element analysis during simulated multidirectional loading. Correlations between screw-specific vertebral geometric parameters and stresses were studied. Angulations in both the sagittal and axial planes affected stresses on the cortical and cancellous bones and the screw. Pedicle screws pointing laterally (vs. straight or medially) in the axial plane during superior screw angulation may be advantageous in terms of reducing the risk of both screw loosening and screw breakage.
authors.affiliation: a Spinal Biomechanics Laboratory, Department of Neurosurgery Research , Barrow Neurological Institute, St. Joseph's Hospital and Medical Center , Phoenix , AZ , USA.
authors.forename: Anna G U S
authors.initials: AG
authors.lastname: Newcomb
authors.affiliation: a Spinal Biomechanics Laboratory, Department of Neurosurgery Research , Barrow Neurological Institute, St. Joseph's Hospital and Medical Center , Phoenix , AZ , USA.
authors.forename: Seungwon
authors.initials: S
authors.lastname: Baek
authors.affiliation: a Spinal Biomechanics Laboratory, Department of Neurosurgery Research , Barrow Neurological Institute, St. Joseph's Hospital and Medical Center , Phoenix , AZ , USA.
authors.forename: Brian P
authors.initials: BP
authors.lastname: Kelly
authors.affiliation: a Spinal Biomechanics Laboratory, Department of Neurosurgery Research , Barrow Neurological Institute, St. Joseph's Hospital and Medical Center , Phoenix , AZ , USA.
authors.forename: Neil R
authors.initials: NR
authors.lastname: Crawford
mesh_terms: D001696:Biomechanical Phenomena; D001863:Bone Screws; D000071556:Cancellous Bone / Q000502:physiology; D003198:Computer Simulation; D000071538:Cortical Bone / Q000502:physiology; D020342:Finite Element Analysis; D006801:Humans; D008159:Lumbar Vertebrae / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D065289:Pedicle Screws; D015203:Reproducibility of Results
keywords: Finite element analysis; non-idealized models; pedicle screw; screw orientation; stress analysis