A Finite-Element Model for Evaluation of Middle Ear Mechanics

In conductive hearing loss cases, 59% involve defects of the incus. For efficient restoration of hearing, the defective incus is normally removed and the mechanical link between the eardrum and inner ear is reconstructed. In cases of incus defects, the reconstruction is normally of the form of a rod, positioned to connect the malleus handle or eardrum directly to the cochlea oval window. A more promising approach to prosthesis design is to reconstruct the chain along more physiologically relevant lines. It has been shown that excellent reconstruction of the ossicular chain can be achieved using a generic incus shape. In a series of in vitro studies, it was shown that secure attachment of the prosthesis to the stapes and malleus, with ionomeric cement, could restore hearing within 10 dB of the original frequency response. This study attempts to model these in vitro findings using a finite element computer model. The goal of the study is to produce a computer model that can be used to simulate different forms of attachment to the prosthesis.