02 Fakultät Bau- und Umweltingenieurwissenschaften
Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/3
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Item Open Access Analysing the bone cement flow in the injection apparatus during vertebroplasty(2023) Trivedi, Zubin; Gehweiler, Dominic; Wychowaniec, Jacek K.; Ricken, Tim; Gueorguiev-Rüegg, Boyko; Wagner, Arndt; Röhrle, OliverVertebroplasty, a medical procedure for treating vertebral fractures, requires medical practitioners to inject bone cement inside the vertebra using a cannula attached to a syringe. The required injection force must be small enough for the practitioner to apply it by hand while remaining stable for a controlled injection. Several factors could make the injection force unintuitive for the practitioners, one of them being the non‐Newtonian nature of the bone cement. The viscosity of the bone cement varies as it flows through the different parts of the injection apparatus and the porous cancellous interior of the vertebra. Therefore, it is important to study the flow of bone cement through these parts. This work is a preliminary study on the flow of bone cement through the injection apparatus. Firstly, we obtained the rheological parameters for the power law model of bone cement using experiments using standard clinical equipment. These parameters were then used to obtain the shear rate, viscosity, and velocity profiles of the bone cement flow through the cannula. Lastly, an analysis was carried out to understand the influence of various geometrical parameters of the injection apparatus, in which the radius of the cannula was found to be the most influential parameter.Item Open Access 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.