Anatomically accurate 3D printed prosthetic incus for ossicular chain reconstruction

Abstract

Middle ear disease often leads to ossicular erosion, impairing auditory function and frequently requiring ossicular chain reconstruction (OCR) for hearing restoration. Columella-type prostheses, commonly used in OCR, have shown limited success due to issues such as displacement and extrusion, highlighting the need for more effective solutions. This study introduces a 3D-printed prosthesis anatomically resembling the human incus bone, referred to as the titanium prosthetic incus, as a potential device for OCR. Utilising Finite Element Analysis (FEA), CT imaging, and 3D printing, the prosthesis was numerically evaluated, fabricated, and experimentally tested to assess its mechanical performance and anatomical fit. The prosthetic incus demonstrated ossicular vibration comparable to healthy control ears, effectively transmitting sound energy to the inner ear. The results revealed that the prosthetic incus offers superior sound transmission performance, particularly at low frequencies (below 1000 Hz), when compared to the PORP, with similar performance at higher frequencies. Additionally, the prosthetic incus has the potential to improve overall stability over traditional PORP devices, with a reduced risk of displacement due to its precise anatomical fitting. This study also suggests that the approach of contralateral imaging and individualised 3D printing enhances the customisation and accuracy of OCR procedures, potentially reducing operative time and improving long-term outcomes. Furthermore, the cost-effective nature of 3D printing makes this solution both clinically viable and scalable. This innovative technique holds promise for advancing OCR by providing a durable, patient-specific prosthetic option that enhances sound transmission and surgical success rates for patients with middle ear ossicular erosion.