Preoperative prediction of stapes exposure during otomicrosurgery based on temporal bone computed tomography images：A cohort observational study

Introduction: This prospective study aimed to evaluate the predictive value of high-resolution computed tomography (CT) scan of the temporal bone in predicting the degree of difficulty of stapes exposure during otomicrosurgery. Methods: Twenty-seven patients with chronic otitis media and conductive or mixed deafness who were scheduled to undergo otomicrosurgery were included in the study. The width of the external auditory canal bone, the stapes to the cone bulge, as well as the stapes to the tympanic sinus distance were measured to indicate stapes exposure difficulty, which was confirmed during operation and divided into hard-to-expose and easily-exposed groups. The differences between the groups were compared; statistically significant parameters were included in the logistic regression model. Statistical significance was set at P<0.05. Results: Coronary and horizontal CT measurements of the stapes to cone bulge distance were statistically significant between the two groups ( P<0.05 and P<0.01, respectively). The CT measurements of the stapes to tympanic sinus and the width of the external auditory canal bone were also statistically significant between the two groups ( P<0.05). Multivariate logistic regression analysis revealed that the bulge distance could be used as an independent predictor of the difficulty of stapes exposure. Conclusion: Preoperative high-resolution CT scans in the coronal and horizontal planes of the stapes to the cone ridge can provide a reference in predicting the difficulty of stapes exposure during otomicrosurgery and deserve further attention.