Analysis of the fossa olfactoria using cone beam tomography (CBT)

Abstract

Conclusion: A cone beam tomography (CBT) examination of the olfactory area with its different variants allows development of an individual anatomical-radiological risk profile of the ethmoid and the identification of so-called ‘dangerous ethmoids.’ Objective: Preoperative imaging performed with high-resolution CBT is imperative for analysis of the risk of injuring the olfactory fossa during sinus surgery. This study aimed to analyze the relevant parameters. Methods: This was a retrospective, single-center study of 141 patients. The Accu-I-Tomo F17 was used. Keros type, the point of the anterior ethmoid artery, and the angle between the lateral lamella and the cribriform plate (αlc) were evaluated. Results: The Keros types were distributed as follows: type I, 13% (αlc: 131°); type II, 64% (αlc: 116°); type III, 23% (αlc: 108°) (p < 0.001). The angle of the olfactory fossa and the position of the anterior ethmoid artery (free course: αlc=112° vs integrated into the skull base: αlc= 120°) was significantly different. Discussion: Surgical procedures in Keros type III where the height of the lateral lamella is much longer than in type II or type I, with an angle of nearly 107° between the lateral lamella and the cribriform plate, are expected to be safer in comparison with Keros type II with 116° and Keros type I with 131°.