Effect of Disease Duration on the Distribution of Otosclerotic Foci Within the Stapes Based on Scanning Electron Microscopy Analysis

Introduction: Otosclerosis is characterized by the presence of abnormal resorption and recalcification of the endochondral layer of the temporal bone, which is not observed in healthy subjects. The result of the alternating occurrence of both processes is the appearance of disorganized and, over time, dense, sclerotic bone tissue underlying the clinical manifestation of the otosclerotic process. Aim: The aim of the work is the chemical analysis of otosclerotic foci of the stapes superstructure with the use of a scanning electron microscope. Material and methods: Patients operated for the first time due to otosclerosis were analyzed. The removed stirrup suprastructures were examined in a Scanning Electron Microscope (SEM) using microanalytical techniques (WDXS – Wavelength-dispersive X-ray spectroscopy TEXS – Transition Element X-ray Spectrometer) and diffraction techniques (2D EBSD – Electron Backscatter Diffraction). Results: In patients with a short medical history, a statistically significant difference in calcium (Ca) concentration was found between the anterior and posterior cruses of stapes. Along with the duration of the disease, a statistically significant difference in calcium (Ca) concentration was observed between the stapes head and its cruses. In the course of the disease, degradation of the microstructure of the stapes bone tissue was observed in a scanning electron microscope. Conclusions: (A) As the otosclerotic process progresses, significant changes in the chemical composition between the individual parts of the stapes superstructure are observed; (B) The observed biochemical changes are accompanied by changes in the microstructure of bone tissue observed in SEM.