Coupled Finite Element Model of the Middle and Inner Ear as Virtual Test Environment for Stapes Surgery.

In order to evaluate the performance of different types of middle-ear prostheses, a model of human ear was developed. The model was created using finite element (FE) method with the ossicles modeled as rigid bodies. First, the middle-ear FE model was developed and validated using the middle-ear transfer function measurements available in literature including pathological cases. Then, the inner-ear FE model was developed and validated using tonotopy, impedance, and relative BM motion level curves from literature. Both models are based on preexisting research with some improvements and were combined into one coupled FE model. The stapes in the coupled FE ear model was replaced with a model of a stapes prosthesis to create a reconstructed ear model that can be used to estimate how different types of stapes protheses perform relative to each other as well as to the natural ear. The influence of the diameter of the prosthesis as well as the influence of the sealing and opening of the gap in the footplate were investigated along with different measures such as maximum basilar membrane displacement, intracochlear pressure, pressure in scala vestibuli, oval and round window volume displacements, and prosthesis displacement. This will help in designing new innovative types of stapes prostheses or any other type of middle-ear prostheses, as well as to improve the ones that are already available on the market.