Finite element evaluation of a novel adjustable-length partial ossicular replacement prosthesis

Partial ossicular replacement prosthesis (PORP) reconstruction is a standard otologic procedure for restoring sound conduction in patients with conductive hearing loss resulting from partial ossicular chain disruption. Current commercial PORP designs exhibit several limitations that may affect long-term hearing outcomes and contribute to complication risks. This study presents a novel adjustable-length PORP and systematically evaluates its biomechanical performance and sound transmission fidelity using a finite element analysis (FEA) framework, thereby providing computational evidence for preclinical feasibility evaluation.

The proposed prosthesis incorporates a deformable bent titanium alloy connecting rod sandwiched between two polyetheretherketone (PEEK) coupling components: a tympanic-side circular disc and a stapes-head bowl. The connecting rod incorporates three independently adjustable bend angles (α, β, γ) that enable intraoperative alignment optimization. An FEA model of the intact human middle ear was constructed, and baseline vibratory transmission characteristics were quantified using the stapes footplate frequency response curve. An FEA model of the middle ear reconstructed with the novel adjustable-length PORP was then generated, and vibratory conduction performance was quantified across continuous length settings spanning 2.3-3.5 mm.

Across the evaluated length range of 2.4-3.5 mm, the prosthesis demonstrates consistent stapes footplate velocity transmission, with predicted hearing loss remaining below 17 dB across the 100 Hz-10 kHz frequency range. Adjusting the prosthesis to the minimum 2.3 mm length increased maximum hearing loss to 34 dB, consistent with structural overcompression.

This finite element analysis provides computational evidence which suggesting the preclinical biomechanical feasibility of the proposed adjustable-length PORP for ossicular chain reconstruction. The predicted results suggest potentially acceptable sound transmission performance and favorable mechanical conditions at the prosthesis-bone interfaces. These findings warrant further experimental validation using physical middle ear models and animal studies to assess long-term safety and functional outcomes.