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Finite Element Analysis of Lumbar Spine Biomechanics Following Cement Augmentation with Different PMMA Volumes: A Comparison with Intact Spine

Authors :

Reihane Yazdani¹ Mohammdjavad (Matin) EinaAfshar² Azadeh Ghoochani³ Nima Jamshidi⁴

1- University of Isfahan 2- Aalborg University, Denmark 3- University of Isfahan 4- University of Isfahan

Keywords :

Bone cement augmentation،Vertebral compression fracture

Abstract :

This study presents a finite element analysis (FEA) of lumbar spine biomechanics following cement augmentation with varying volumes of polymethylmethacrylate (PMMA), aiming to identify the optimal volume for vertebral stability while minimizing stress on adjacent segments. A three-dimensional model of the L2–L3 motion segment was constructed from CT scans of a 50-year-old female patient using MIMICS and 3-Matic software. The cortical shell thickness was set to 1 mm, endplates to 0.8 mm, and the intervertebral disc was modeled based on patient anatomy and literature. Cement was idealized as a cylinder coaxial with a pedicle screw and embedded within the trabecular bone. Three cement volumes—1.0 mL, 1.5 mL, and 2.5 mL—were analyzed alongside an intact control model. Boundary conditions included full constraint of L3 and application of compressive and bending loads to L2. Simulations were performed using Abaqus CAE 2022 under dynamic explicit conditions. Results showed that 1.5 mL cement reduced compressive stress by 29.9%, while 2.5 mL yielded the greatest reductions in flexion (56.2%), lateral bending (2.5%), and axial rotation (3.3%). The intact vertebra exhibited maximum von Mises stress of 86.35 MPa under compression, compared to 60.5 MPa and 70.54 MPa for 1.5 mL and 2.5 mL cement, respectively. These findings suggest that moderate cement volumes offer superior biomechanical performance across multiple loading scenarios. Despite modeling simplifications, the study supports the use of simulation-based planning to optimize cement volume and enhance procedural safety in vertebral augmentation.