The natural vibration characteristics of human ossicles.

BACKGROUND Recently, a model of the ossicular chain for finite element analysis has been developed. However, the natural vibration characteristics of human ossicles have never been studied. Herein, we investigated the dynamic characteristics of the coupling of in-vivo ossicles using finite element analysis. METHODS The geometry of the ossicular chain was obtained by high-resolution computed tomography of the temporal bone, and a 3D model of the ossicular chain was reconstructed by the medical imaging software, Amira®. The file was then imported into the finite element analysis software, ANSYS®. The natural vibration characteristics of human ossicles were measured by finite element analysis. RESULTS The characteristic dimensions of the model were measured and compared with previously published data. The malleus resonated to sound stimuli at 3 kHz and 4 kHz; the incus and stapes did not resonate to sound stimuli at any frequency. A coupling of the incus and malleus easily resonated to sound stimuli at 5 kHz. A coupling of the incus and stapes easily resonated to sound stimuli at 3 kHz. The coupling of the ossicular chain easily resonated to sound stimuli at 5 kHz, 6 kHz and 8 kHz. CONCLUSION The dynamic characteristics of the ossicular chain were analyzed by finite element analysis method. The characteristics of a free vibration model of the ossicles could be determined, which would be helpful in evaluation and consultation for ossicular prosthesis development.