02 Fakultät Bau- und Umweltingenieurwissenschaften

Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/3

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Author: search.filters.author.Trivedi, ZubinSubject: search.filters.subject.624

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    A continuum mechanical porous media model for vertebroplasty : numerical simulations and experimental validation
    (2023) Trivedi, Zubin; Gehweiler, Dominic; Wychowaniec, Jacek K.; Ricken, Tim; Gueorguiev, Boyko; Wagner, Arndt; Röhrle, Oliver
    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.
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    Simulating vertebroplasty using a multiphase continuum-mechanical approach : rheological characterization, numerical simulations, and experimental validation
    (Stuttgart : Institute for Modelling and Simulation of Biomechanical Systems, Chair of Continuum Biomechanics and Mechanobiology, University of Stuttgart, 2024) Trivedi, Zubin; Röhrle, Oliver (Prof., PhD)
    Percutaneous vertebroplasty is a surgical procedure for treating vertebral fractures involving injection of a so-called "bone cement'' into the vertebra. This Ph.D. thesis aimed to develop a computational model for simulating vertebroplasty, and thereby help practitioners determine the best operating parameters specific to each patient. The computational model employs a multiphase continuum-mechanical approach based on the Theory of Porous Media, along with discretization and upscaling methods specifically chosen and modified to suit the application. Apart from this, experiments were carried out to understand the behaviour of the bone cement in the context of vertebroplasty so that its behaviour can be correctly modelled. The developed computational model is validated using experiments done using a simple benchmark experiment. The simulations shed light on some crucial mechanical aspects of vertebroplasty that could determine the success or failure of the procedure.