Modeling of material injection processes into porous

Background

Vertebroplasty has become an important technique for stabilization of osteoporotic vertebral fractures and other weakening lesions such as angioma or metastatic tumors. However, this procedure presents a significant risk through cement leakage that can result in serious complications such as pulmonary embolism or compressions of nerve roots or the spinal cord. Simulations of the bone cement injection processes could predict injection rates, injection pressures, bone cement distribution within the vertebra and the probability of cement leakage, thus providing a valuable risk assessment tool. However, risk assessment can only be performed if realistic simulations of the entire vertebra are performed.

Goal

To collect experimental data by means of quasi-continuous CT scanning and to model material injection processes applied to vertebroplasty describing bone cement flow behavior and distribution, biomechanical behavior at the interface between bone cement and trabecular structure, and bone cement curing. 

Results

A bone cement injector was developed and used in the proof-of-concept experimental phase of the project. Polyurethane foam samples with structure similar to trabecular bone were injected with gelatin containing contrast medium instead of fast-hardening bone cement. The force applied to the plunger of the syringe during CT scanning was recorded at 10 Hz. An animation of the 3D cement expansion was created from the recorded CT image data and will serve for parametrization and validation of the numerical models at University of Stuttgart.

Fund:

German Research Foundation (DFG), Special Research Area (SFB), ARI funding: EUR 100'000, Period: 2018-2021.