High porosity and low matrix mineralization in incus specimens of cholesteatoma patients

Objective Cholesteatoma can lead to destruction of bony structures in the petrous bone. The aim of this study was to analyze the bone quality of the incus in cholesteatoma patients and to compare these with specimens from patients with chronic otitis media (COM) without cholesteatoma or normal findings.

Methods The study cohort included 14 patients with cholesteatoma, 9 with COM without cholesteatoma, and 8 controls. While incus specimens in the first two groups were obtained intraoperatively, the control group consisted of incus specimens from skeletally intact donors collected during autopsy. Clinical data were obtained from the electronic medical records. All specimens were evaluated by micro-computed tomography, histomorphometry on undecalcified sections, quantitative backscattered electron imaging and nanoindentation.

Results Although a considerable heterogeneity was observed, the porosity of incus specimens was higher in cholesteatoma than in COM without cholesteatoma (p<0.05). Histological assessment revealed higher osteoid levels and osteocyte numbers, but unaltered osteoblast and osteoclast indices. The incus of cholesteatoma patients showed lower matrix mineralization (CaMean) compared to the control group (p<0.0001) and COM without cholesteatoma (p<0.05). The incus porosity was higher in patients with intraoperative involvement of >1 ossicle but did not correlate with cholesteatoma stage or degree of hearing loss.

Conclusion We demonstrated increased porosity and impaired matrix mineralization as distinct features of auditory ossicles in cholesteatoma. The fact that no association between micromorphological data and hearing function could be established suggests a multifactorial pathogenesis of hearing loss.

Tim Rolvien, Sophia Häußler

Publication History

Article published online:
12 May 2023