THE GEOMETRICAL DIMENSIONS OF THE CARTILAGE TRANSPLANT FOR A POSTEROSUPERIOR QUADRANT OF THE TYMPANIC MEMBRANE WITH PATHOLOGICAL CHANGES OF THE ELASTIC PROPERTIES
The aim of the study is to develop recommendations for the surgical reconstruction of the tympanic membrane of the middle ear and to improve of hearing. Finite-element calculations of the eigenfrequencies for the healthy middle ear oscillating system, for the middle ear with pathological changes of the tympanic membrane and for the middle ear with the cartilage transplant on the tympanic membrane are carried out. Finite-element model of the middle ear consisting of the tympanic membrane, malleus, anvil and stapes is obtained on the basis of the tomographic data. The model of the tympanic membrane is composed of three layers; its physical and mechanical properties depend nonlinearly on the spatial coordinates. The geometrical dimensions of the cartilage transplant in various pathologies of the tympanic membrane are defined for reconstruction the sound conditions relevant to the functions of the healthy eardrum. The obtained results can be used to predict the thickness of the cartilage transplant needed to restore the functions of the middle ear.