Finite element analysis of Stryker Xia pedicle screw in artificial bone samples with and without supplemental cement augmentation

Abstract

A validated, using in vitro biomechanical testing, finite element model was used to evaluate the affects of (1) cement augmentation and (2) an intact posterior cortex in osteoporotic bone. The presence of augmentation and/or a posterior cortical cortex increased the stabilization of the pedicle screw 2-5 fold. Placement of cement influenced failure load and toggle; with distal placement having the largest increase in failure load and decrease in cephalad-caudad toggle. The presence of posterior cortex caused a decrease in the amount of toggle, a proximal shift of the center of rotation and an increase in the maximum failure force.

Surgical Management of Spinal Conditions in the Elderly Osteoporotic Spine

“…45 In addition, concentrating cement around the tips of the screws seems to maximize this enhancement effect. 46 There are some theoretical risks when using cement augmentation of pedicle screws. Those include cement extravasation into the venous system with risk of embolism, 47 extravasation into the spinal canal with risk of neurological injury, or extravasation into an adjacent disc.…”

Biomechanical role of cement augmentation in the vibration characteristics of the osteoporotic lumbar spine after lumbar interbody fusion

“…Similarly, there are also a lot of numerical results from the finite element analysis. The finite element analysis by Ferris et al demonstrated that placement of cement influenced failure load and toggle, with distal placement having the largest increase in failure load and decrease in cephalad-caudad toggle [ 20 ]. Polikeit et al investigated the effect of cement augmentation on an osteoporotic fusion lumbar spinal unit by using finite element analysis.…”