Background: Otosclerosis is a disease that occurs only in humans, in the course of which there are foci of pathological ossification in the temporal bone. The etiology of the disease is not fully understood. Treatment of the conductive component of hearing loss is surgical. The results of the treatment are influenced by factors related to the surgery, the local condition of the middle ear and the function of the inner ear. Aim: The aim of the study is to identify factors influencing the improvement of hearing in patients treated surgically due to otosclerosis. Methods: The study included patients who underwent otosclerosis for the first middle ear surgery and underwent stapedotomy. Considering the factors that may affect the outcome of surgical treatment, the patients qualified for the analysis were divided into subgroups. All patients underwent a medical history and physical examination of otorhinolaryngology and a complete set of audiological examinations. Results: A statistically significant reduction in cochlear reserve was observed in all patients after stapedotomy. The beneficial effect of the performed treatment on the improvement of threshold values of bone conduction in patients with mild sensorineural hearing loss was also confirmed. Intraoperative removal of adhesions present in the tympanic cavity significantly improved hearing in terms of bone conduction values, especially at 500Hz. Conclusion 1. The conducted study confirmed the influence of factors related to the local condition of the middle ear lining on the final result of otosclerosis surgery. 2. Audiometric markers of cochlear otosclerosis, observed before surgical treatment, are an unfavorable factor in the improvement of hearing after the performed treatment.

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.

Objective The assessment of bone conduction thresholds in patients with conductive hearing loss is not a full measure of the function of the inner ear due to the weakening of the influence of middle ear components on bone conduction. This relationship has been called the ‘Carhart effect’. Methods The retrospective analysis covered 977 patients diagnosed and treated for middle ear diseases from 2010 to 2020. The Carhart effect was considered to be an increase in the bone conduction threshold by a minimum of 10 dB relative to adjacent frequencies. The study was performed with the aim of assessing the presence of the Carhart effect in the course of middle ear diseases in pretreatment analysis. Results The Carhart effect was observed in 532 cases, most often in patients with chronic otitis media and otosclerosis. It was least often observed in patients with otitis media with effusion. In otitis media with effusion, the Carhart effect was more often noted for the frequency of 4000 Hz, in otosclerosis for the frequency of 2000 Hz. In patients with chronic otitis media, this effect for the frequency of 4000 Hz was correlated with the location of inflammatory changes in the attic area. The presence of inflammatory lesions in the oval window area was associated with the presence of the Carhart effect for the frequency of 2000 Hz. Conclusions 1. The frequency of the Carhart effect observed in diseases of the middle ear does not depend on the disease entity but on the type and location of abnormalities in the middle ear. 2. The Carhart effect observed for the frequency of 4000 Hz coexists with the localization of lesions in the range of the malleus and incus, and for the frequency of 2000 Hz, it is partially associated with abnormalities in the range of stapes and oval window.