The prognostic influence of pre-surgery bone conduction values on the improvement of hearing in patients treated surgically as a result of middle-ear conditions

Introduction: The influence of the mechanics of the middle ear on the function of the inner ear has been studied for many years. Among surgeries performed in the middle-ear area, those restoring full functionality of the system transmitting sound inside the middle ear may be pointed out as those fully restoring the mechanical influence of the middle ear on the function of the inner ear. Aim: The aim of the performed analysis is to find the prognostic importance of measured pre-surgery values of bone conduction on the improvement of hearing in patients operated as a result of middle-ear disorders. Material and methods: The analysis included 271 patients hospitalised and operated on due to otosclerosis or perforation of the tympanic membrane between 2016 and 2019. Only patients who had not had a surgical operation within the middle ear prior to the study were included. An audiological assessment was performed with the use of pure tone thresholds audiometry. Results: A beneficial influence of the performed surgery on the improvement of bone conduction was observed in patients, in which the average threshold value of bone conduction measured before the surgery did not exceed 40 dB. In cases of the perceptive component of hearing impairment being higher than 40 dB, no statistically significant, beneficial influence of a performed stapedotomy or myringoplasty on the change of bone conduction thresholds was observed. Conclusions: The perception component of hearing impairment up to 40 dB indicates bone conduction improvement after surgical restoration of the influence of middle-ear mechanics on the inner ear in patients treated as a result of otosclerosis, as well as of eardrum perforation.