Spatial Quantification of Alterations in Ossicular Microarchitecture Related to Middle Ear Disease

• Synchrotron phase-contrast microtomography reveals microarchitecture differences in healthy and pathological ossicles. • Lower mineral density and higher porosity in cholesteatoma cases may compromise autograft stability. • Quantitative analyses complement visual evaluation to assess in-depth ossicular integrity. The human auditory ossicles –malleus, incus, and stapes– are critical for hearing, yet the middle ear that houses them is frequently affected by inflammatory conditions such as chronic otitis media with and without cholesteatoma, leading to ossicular chain damage. In cases of severe degradation, reconstructive surgery often involves ossiculoplasty using sculpted autografts. However, the impact of inflammation and surgical sculpting on the in-depth microarchitecture of ossicles remains poorly understood. This study investigates the structural integrity of ossicles (incudes and mallei) affected by cholesteatoma, previously sculpted autografts, and healthy controls using high-resolution synchrotron-based X-ray microtomography. Quantitative spatial analysis of mineral density, porosity, vascular canal density, and lacunar volume density reveals that cholesteatoma induces not only surface degradation but also significant internal alterations, including reduced mineral density and increased porosity, particularly around vascular canals. These changes suggest compromised structural stability, which may affect the suitability of ossicles for autologous grafting. Our findings highlight the need for improved assessment criteria during ossiculoplasty and underscore the importance of understanding ossicle microarchitecture and its alterations to optimize surgical outcomes.