Stability analysis of middle ear dynamic system after incudus joint repair under intense stimuli

Abstract

High intensity noise levels can lead to dislocation in the ossicular chain, particularly at the incus and the incudostapedial joint, significantly impacting hearing ability. However, the sensitivity of the middle ear system following ossicular chain restoration to intense external stimuli and the reconstructed material's nonlinear characteristics are still poorly understood. In order to investigate these aspects, a multi-degree-of-freedom mechanical model is developed on healthy and pathological ossicular chain reconstructions. Firstly, implant material parameters are determined by analyzing the natural frequencies of the system in an undamped condition. Secondly, the dynamic characteristics of the middle ear system are examined under various external excitations. Thirdly, utilizing a multi-time scale method, an approximate solution is derived for near-resonant frequency systems. Finally, the periodic solution stability is analyzed and assess how reconstructed middle ear parameters influence it. It is important to note that in healthy patients, post-ossicular chain reduction should be maintained in-ear sound pressure below 95 dB SPL, while for patients with pathology reconstruction, it should be kept below 65 dB SPL.