Miaolin Feng

STUDY ON THE ROLE OF OSSICULAR JOINT USING FINITE ELEMENT METHOD

The lever ratio, the vibration mode and the stiffness of the ossicular joints were studied using the finite element (FE) analysis of the response of human ear under the outer ear sound excitation. The three-dimensional FE model was constructed based on serial micro CT images of a temporal bone block, and validated through comparison with the experimental data from previous literatures. The displacements of the umbo and stapes footplate and the vibration mode of the ossicles under different grades of stiffness of middle ear components were derived. It is suggested that the flexible ossicular joint combined with the shift of rotation axis causes the increase of lever ratio at high frequency. In addition, the flexible incudostapedial joint (ISJ) can reduce sound transmission especially at high frequency, meanwhile it also permits more vibration energy transmitted to the piston-like directions.

Fatigue analysis of tympanic membrane after ossiculoplasty

Abstract Conclusion: A tentative conclusion was made that the finite element method can be used to investigate the fatigue life of the tympanic membrane after ossiculoplasty; the main reason of the extrusion of the tympanic membrane may not be blamed to the fatigue mechanism under normal sound pressure. Objective: This study was to investigate the extrusion of the prosthesis from the tympanic membrane at post-ossiculoplasty by finite element method. Methods: A finite element model of the human middle ear has been constructed and used as the model of the constructed middle ear at post-ossiculoplasty. Then the fatigue life of the tympanic membrane was calculated under different sound pressure level using this model. Results: The tympanic membrane would not be extruded under normal sound pressure level. The sound pressure level which caused the tympanic membrane to crack in less than 3 years was higher than 145.17 dB (362.5 Pa).