Minimizing Pedicle Screw Pullout Risks: A Detailed Biomechanical Analysis of Screw Design and Placement
Résumé
STUDY DESIGN: Detailed biomechanical analysis of the anchorage performance provided by different pedicle screw design and placement strategies under pullout loading. OBJECTIVE: To biomechanically characterize the specific effects of surgeon-specific pedicle screw design parameters on anchorage performance using a finite element model (FEM). SUMMARY OF BACKGROUND DATA: Pedicle screw fixation is commonly used in the treatment of spinal pathologies. However, there is little consensus on the selection of an optimal screw type, size, and insertion trajectory depending on vertebra dimension and shape. METHODS: Different screw diameters and lengths, threads and insertion trajectories were computationally tested using a design of experiment (DOE) approach. A detailed FEM of an L3 vertebra was created including elastoplastic bone properties and contact interactions with the screws. Loads and boundary conditions were applied to the screws to simulate axial pullout tests. Force-displacement responses and internal stresses were analyzed to determine the specific effects of each parameter. RESULTS: The DOE analysis revealed significant effects (P