Bone degeneracy a parameter to identify suitable pedicle screw for Lumbar Vertebrae: a biomechanical analysis through finite element study

Abstract

The present work aims to elucidate the influence of different diameter pedicle screw considering vertebrae bone degeneracy on lumbar vertebrae. Segment L2-3 considered and subjected to various loading conditions to characterize the biomechanical aspects for optimum pedicle screw selection. A three-dimensional (3D) finite element (FE) model of lumbar vertebrae (L2-3) was considered to analyze the numerous bone responses and effect of various pedicle screw. Multi-sliced computed tomography (CT) images were considered to generate surface and solid model of vertebrae L2-3. Intact and implanted models with three different pedicle screw diameter with four degeneracy conditions were used for finite element analysis. Von Mises stress distribution over intervertebral disc, and bone-screw interface was examined for various screw diameters and bone conditions. Results for flexion, extension, lateral bending, axial twist were compared among the various computational models. FE simulated results have shown significant variations in von Mises stress distribution due to combined loading conditions over bone degeneracy. Results shows that the 6.0mm pedicle screw diameter possesses least stress values at bone-screw interface.