Anatomical and clinical evaluation of the tympanic tegmen and mastoid bone with MDCT

The aim of this study was to measure the mastoid tegmen and tympanic tegmen depths and mastoid bone thickness, assess gender and side differences and evaluate the relationship between the measured structures, classify the mastoid tegmen, tympanic tegmen and mastoid bone and indicate risk group in population among the patients who had temporal region tomography for any reason. 300 individuals aged between 18-82 years who had no pathology disrupting the structure of the temporal region were included to the study. Mastoid tegmen and tympanic tegmen depths and mastoid bone thickness were measured in both right and left side. Depths of tympanic tegmen and mastoid tegmen, mastoid bone thickness were measured on either temporal bones. Mastoid tegmen and tympanic tegmen were found to be lower on the right side than on the left side (p=0.025, p=0.0001). Right mastoid bone thickness and right mastoid tegmen were found to be lower in females (p=0.03, p=0.033). Thin right mastoid bone was observed in 64.67% of females and 47.33% of males; the thin group was more common in females (p=0.02). Low level mastoid tegmen on the left side was 54% in females and 44% in males; females were more in the lower class (p=0.028). Classification of tympanic tegmen was also examined; the rate of low level tympanic tegmen was 44.67% in females and 32.67% in males, low level tympanic tegmen was detected more often in females (p=0.033). Risk classification for surgeries of mastoid region was as follows: on the right temporal bone males were higher in the low risk group and females were higher in the high-risk group (p=0.003). Risk classification created for the surgeries of mastoid and middle ear regions, on the right temporal bone was found that female are more on the middle and high risk group than male (p=0.008). In addition, as the thickness of the mastoid bone increased, the level of mastoid tegmen and tympanic tegmen increased. Keywords: Mastoid region, mastoid tegmen, tympanic tegmen.