Comparison of visualization of the middle ear by microscope and endoscopes of 30° and 45° through posterior tympanotomy

INTRODUCTION: Endoscopic-assisted microsurgery of the middle ear enables the field of view of the surgeon to be expanded during the removal of inflammatory tissue from the tympanic cavity and during myringo- and ossiculoplasty. Canal wall up tympanoplasty with posterior tympanotomy is a gold standard in surgical treatment of chronic otitis media. Most applications of endoscopy in middle ear surgery concern exclusively the endoscopic transcanal approach. AIM: To determine the usefulness of endoscopic visualization during the standard surgical approach through the posterior tympanotomy. MATERIAL AND METHODS: The study compared the visualization of the elements of the middle ear through the posterior tympanotomy by endoscopes with 30° and 45° optics and a microscope. Posterior tympanotomy was performed in eleven temporal bones. Visualization of the tympanic recesses was assessed on a subjective scale. A microscope and 30° and 45° endoscopes were used for inspection of the hypotympanum, sinus tympani, Eustachian tube, Prussak's space and footplate. Friedman ANOVA test and Dunn's multiple comparisons test were used for statistical analysis of the data. RESULTS: Visualization of particular recesses by endoscopes, both 30° and 45°, was excellent, while the microscopic view was statistically significantly worse, especially for sinus tympani, Prussak's space and footplate. There were no significant differences in visibility of the middle ear spaces between the two types of endoscopic optics. CONCLUSIONS: Additional application of the endoscopes during middle ear surgery provides valuable information due to excellent visualization of key recesses usually hidden from the microscope.