Multidetector Computed Tomography Used in Evaluation of Olfactory Fossa Depth in a Tertiary Hospital in Eastern Region of Nepal: A Descriptive Cross-sectional Study.

Introduction: Olfactory fossa (OF) is a depression in most infero-medial portion of anterior cranial fossa formed by cribriform plate, crista galli and lateral lamella of cribriform plate (LLCP). LLCP being thinnest and extremely variable parts, more prone for iatrogenic injury during sinus surgery in case of asymmetric and deep OF. Multidetector computed tomography (MDCT) is frequently used imaging modality in the evaluation of paranasal sinus. The objective of the study is to classify the OF depth according to the Keros classification.

Methods: In this ethically approved prospective, cross-sectional descriptive study, CT scan was done in 530 consecutive patients from February 2022 to July 2023. Coronal CT images of paranasal sinuses and nose were used to measure the OF depth. The data collected was analyzed using SPSS.

Results: Out of 530 patients included in this study, 310 (58.49%) were male and 220 (41.51%) were female with mean age of 40.46±11.56 years. Total of 1060 olfactory fossa were analyzed with mean depth of 4.96±1.88 mm. In our study, 310 (29.24%) had type I, 730 (68.88%) had type II and 20 (1.88%) had type III according to Keros classification.

Conclusions: Keros type II OF is more common. The dangerous type III OF having low prevalence, more commonly seen on right side and in males.