title: Pull-out strength of pedicle hooks with fixation screws: influence of screw length and angulation.
abstract: The pull-out force of thoracic spinal pedicle hooks secured by long fixation screws engaging the posterior portion of the vertebral endplate was measured. The performance of these hooks was compared with that of hooks using a shorter screw and different screw orientation such that the vertebral endplates were not perforated. The longer and differently angulated screws, engaging the endplate, significantly enhanced the fixation potential of the hooks.
authors.affiliation: M.E. Müller Institute for Biomechanics, University of Bern, Switzerland.
authors.forename: U
authors.initials: U
authors.lastname: Berlemann
authors.forename: P A
authors.initials: PA
authors.lastname: Cripton
authors.forename: L
authors.initials: L
authors.lastname: Rincon
authors.forename: L P
authors.initials: LP
authors.lastname: Nolte
authors.forename: F
authors.initials: F
authors.lastname: Schläpfer
mesh_terms: D001863:Bone Screws / Q000592:standards*; D002102:Cadaver; D004867:Equipment Design; D006801:Humans; D016268:Internal Fixators / Q000592:standards*; D008297:Male; D008875:Middle Aged; D013314:Stress, Mechanical; D013904:Thoracic Vertebrae / Q000601:surgery*