Dynamic analysis and material optimization of ossicular replacement prostheses

Abstract

Recent advancements in middle ear implant technologies have opened new possibilities in the treatment of conductive hearing loss. This study presents a comprehensive dynamic analysis and material-based optimization of Total Ossicular Replacement Prostheses (TORPs) using a validated Finite Element Model (FEM). A three-dimensional anatomically accurate model of the human middle ear was reconstructed from CT scan data and subjected to acoustic loading (90 dB SPL) over the frequency range of 250–8000 Hz. Three clinically relevant biocompatible materials – Titanium (Ti), Hydroxyapatite (HA), and Polyetheretherketone (PEEK) – were evaluated across three prosthesis volume scales (100%, 75%, and 50%). Displacement results showed that prosthesis miniaturization leads to a substantial loss in mechanical performance: the 50% model exhibited up to 90% reduction in displacement compared to the full-size 100% model. Among materials, titanium yielded the highest displacement (33.9 μm), followed by hydroxyapatite (22.9 μm), and PEEK (18.5 μm). Strain values were highest in PEEK due to its lower stiffness, while titanium and HA displayed more stable responses across all volumes. Von Mises stress levels were low (<3 × 10^-4 Pa) under acoustic excitation, but hydroxyapatite at 50% scale exhibited localized stress increases. These results highlight the critical role of both size and material in prosthesis design, emphasizing the need for balance between flexibility and structural integrity. The findings contribute to the development of patient-specific TORPs with optimized biomechanical behavior for improved auditory restoration.