A Comparative Study of Computed Tomography Findings versus Intraoperative Findings of Level of Tegmen Plate in Chronic Otitis Media: An Observational Study

Objective: To compare the computed tomography findings with intraoperative findings of the level of tegmen plate with respect to the superior most part of the lateral semicircular canal in patients with Chronic Otitis Media. This study was attemptted to provide an objective assessment of the level of tegmen mastoideum. Materials and Methods: The level of tegmen plate with respect to the superior most part of the lateral semi-circular canal was measured preoperatively using HRCT scan of slice thickness of 0.6 mm with a software - RadiAnt DICOM Viewer 64-bit version in sagittal plane. The distance between these two planes was measured intraoperatively using micro ear straight pick and Vernier Calipers. Results: 75 participants (thirty-three male & forty-two female) with chronic otitis media underwent computed tomography preoperatively and surgery. No significant difference was found in the height of tegmen measured preoperatively using HRCT temporal bone and intraoperatively (p value – 0.16). The tegmen plates were classified as low lying (2.0 -2.49 mm), intermediate lying (2.49–2.99 mm) and high lying (3.0 -3.49 mm). Conclusion: Computed tomography findings of tegmen height correlates well with the intraoperative findings. An objective assessment of the level of tegmen mastoideum can provide the surgeon an idea of the severity of low lying level of tegmen to be expected and hence likely surgical problems. Based on this study, a classification system of level of tegmen plate has also been proposed.