Morphometric evaluation of the olfactory fossa on cone BEAM computed tomography images

The lateral lamella of the cribriform plate (LLCP) is one of the common sites of injury during anterior skull base surgeries. Visualization of the anterior ethmoidal artery (AEA) is considered an important anatomical landmark in these surgeries. Studies associating these structures with the morphology of olfactory fossa are limited. The aim of this study is to contribute to the literature by examining in detail the morphology of olfactory fossa and surrounding bone structures in Cone Beam Computed Tomography (CBCT) images. For this purpose, CBCT images of 300 individuals aged 18-85 years were evaluated retrospectively. A total of 11 parameters were measured, 10 in the coronal section and 1 in the transverse section. Measurement and typing of olfactory fossa, lateral lamella and cribriform plate were done. The Keros, Gera and Yenigün classifications were examined. Comparison of parameters between gender and sides was examined. As a result of the measurements, 18% Keros type I, 62% Keros type II, and 20% Keros type III were detected. Various factors such as the depth of the olfactory fossa, the anatomical variations of LLCP and the course of AEA are extremely important in skull base injuries and complications that may occur during surgical procedures. Examination of the different variants of the olfactory fossa region with CBCT allows the development of the individual anatomical-radiological risk profile of the ethmoid bone and the identification of "dangerous ethmoids''. Preoperative imaging with CBCT can be used to analyze the risk of damage to the olfactory fossa during sinus surgery. In this study, the anterior skull base was examined according to the Keros, Yenigün and Gera classification, and a 3-dimensional configuration was provided. Among the parameters, type II olfactory fossa according to Keros, type II cribriform plate according to Yenigün and type II lateral lamella according to Gera were found compatible. It is thought that the findings about the olfactory fossa and surrounding anatomical structures obtained in this study will guide clinicians especially in anterior approach skull base surgeries.