Assessment of eigenfrequencies of the middle ear oscillating system: Effect of the cartilage transplant

Abstract

Finite-element models of the intact middle ear and the diseased one with the eardrum subjected to retraction in the posterosuperior quadrant are proposed. Because the natural frequencies of the middle ear oscillating system are the principle dynamic characteristics, finite-element calculations of eigenfrequencies for both the normal middle ear and the middle ear with pathological changes of the tympanic membrane in the posterosuperior quadrant are carried out. The geometrical model of the middle ear consisting of the eardrum, malleus, incus, and stapes was obtained on basis of the tomographic data. When the eardrum has a retraction pocket, a cartilage transplant superimposed on the posterosuperior quadrant is considered as a reinforcing element. The optimal thicknesses of the cartilage transplant are defined in such a manner that the natural frequencies of the reconstructed middle ear were as close to those of the normal middle ear as possible. The obtained results can be used to predict the thickness of the cartilage transplant needed to restore the functions of the human middle ear.