Classification and radiological evaluation of olfactory fossa measurements using cone- beam computed tomography: A retrospective study

The aim of our study is to master the anatomy, variation and pathology of the region by using cone-beam computed tomography, which is more practical and more economical, with less radiation exposure than computed tomography. In this way, it is aimed to provide guidance to otolaryngologists and maxillofacial surgeons, to obtain data on anterior skull base anatomy of the Popülation aged 18 and over, and to reduce complication rates by obtaining normative data. In our study, CBCT images of 120 individuals aged between 18 and 80, selected from the archive of Ankara University Faculty of Dentistry, were included. Individuals according to their age; It is divided into 3 groups as 18-34 years old, 35-60 years old and 60+ years old. 50% of individuals are female and 50% are male. In our study, the depth of the olfactory fossa was measured on both coronal and sagittal sections and grouped according to the Keros classification and comparisons were made. In addition, the width of the olfactory fossa was measured in the coronal section, the nasal septum deviation was examined and compared with other parameters. Paranasal sinuses were evaluated and the degree of opacification was evaluated according to the Lund-Mackay classification. All parameters were compared with right/left, gender, age and other parameters and statistical significance was checked. Based on the results obtained; In coronal measurements, the olfactory fossa depth was observed as Keros Type 2 in 56.7% of the individuals included in the study and this is the highest rate. Later, Keros Type 1 with 33.3% and Keros Type 3 with 10% were seen. In sagittal measurements, the olfactory fossa depth was observed as Keros Type 2 in 63.3% of the individuals included in the study and this is the highest rate. Later, Keros Type 1 with 30.8% and Keros Type 3 with 5.8% were seen. Nasal septum deviation was observed in 54.2% of the individuals included in the study, and 37 of the individuals included in the study had deviations to the right side and 28 to the left side. Olfactory fossa width values in Keros (coronal) and Keros (sagittal) Type 1 groups on the right side are significantly lower than in Type 2 and Type 3 groups. There is a significant dependence between the Keros (coronal) groups and the Keros (sagittal) groups. The rate of Keros (coronal) Type 2 group being in the Keros (sagittal) Type 2 group (94.4%) was significantly higher than those in the other Keros (coronal) group. Except for the aforementioned cases, no statistical significance was found between any of the groups. Also among the keros (coronal) groups, the ratio of right/left asymmetry was 33.3%; The rate of asymmetry among the keros (sagittal) groups was found to be 29.2%. Keywords: CBCT, Lund-Mackay staging, olfactory fossa, paranasal sinus