Graft thickness assessment for surgery of retraction pocket of the middle ear based on finite-element analysis of eigenfrequencies of the eardrum oscillating system

The aim of this study is to formulate recommendations for surgery of retraction pocket of the tympanic membrane and improving of hearing. Finite-element analysis of the eigenfrequencies of the oscillatory systems for normal middle ear, middle ear with pathology of tympanic membrane and middle ear with cartilage graft are carried out. The finite-element model of the middle ear consists of a tympanic membrane, a malleus, an anvil and a stapes. Pathological changes of the tympanic membrane elastic properties are described by a change of the modulus of elasticity. The geometric dimensions of the cartilage graft of the tympanic membrane are assessed to generate the acoustic conditions corresponding to the hearing functions of the normal tympanic membrane. The obtained results can be employed to estimate the thickness of the cartilage graft for restoring of the middle ear functions by means of reconstruction of the tympanic membrane with a retraction pocket.