A continuum mechanical porous media model for vertebroplasty: Numerical simulations and experimental validation

TL;DR

This paper introduces a validated continuum-mechanical model for vertebroplasty that predicts cement injection outcomes, helping to prevent leakage and improve surgical planning through numerical simulations and experimental validation.

Contribution

The work develops a novel multiphase porous media model for vertebroplasty, validated against experiments, and identifies optimal rheological modeling methods for accurate simulations.

Findings

Semi-analytical averaging of viscosity yields best simulation results.

Higher cement viscosity than marrow ensures stable injection.

Model accurately predicts cement flow and interdigitation.

Abstract

The outcome of vertebroplasty is hard to predict due to its dependence on complex factors like bone cement and marrow rheologies. Cement leakage could occur if the procedure is done incorrectly, potentially causing adverse complications. A reliable simulation could predict the patient-specific outcome preoperatively and avoid the risk of cement leakage. Therefore, the aim of this work was to introduce a computationally feasible and experimentally validated model for simulating vertebroplasty. The developed model is a multiphase continuum-mechanical macro-scale model based on the Theory of Porous Media. The related governing equations were discretized using a combined Finite Element - Finite Volume approach by the so-called Box discretization. Three different rheological upscaling methods were used to compare and determine the most suitable approach for this application. For validation, a benchmark experiment was set up and simulated using the model. The influence of bone marrow and parameters like permeability, porosity, etc., was investigated to study the effect of varying conditions on vertebroplasty. The presented model could realistically simulate the injection of bone cement in porous materials when used with the correct rheological upscaling models, of which the semi-analytical averaging of the viscosity gave the best results. The marrow viscosity is identified as the crucial reference to categorize bone cements as high- or low- viscosity in the context of vertebroplasty. It is confirmed that a cement with higher viscosity than the marrow ensures stable development of the injection and a proper cement interdigitation inside the vertebra.