Finite element modeling of pedicle screw fixation considering patient-specific bone density.

Abstract

Surgical instrumentation and fusion are necessary in severe cases of spinal deformity. In patients with reduced bone quality, pedicle screw fixation remains challenging due to possible loosening or pullout. The objective was to develop and validate a comprehensive finite element model of pedicle screw fixation considering patient-specific bone density. A bi-planar multi-energy X-ray derived algorithm personalized vertebral bone mechanical properties. It was tested against a reference FEM without patient-specific density (trabecular bone modeled as homogeneous), to assess biomechanical performance. Screw dimensional specifications and trajectory were parametrically modeled, and fixation performance was tested under axial pull-out loads.