Frontal sinus outflow tract: Multi-detector CT assessment

Abstract

IntroductionKnowledge of the normal anatomical variants is critical for safe endoscopic navigation during FESS. The frontal sinus outflow tract FSOT includes the frontal infundibulum, ostium and recess respectively in the direction of the drained secretions. The original classification of Bent and Kuhn (B&K) divided the frontal infundibulum cells into four categories. Lund and Mackay scoring system (LMS) is a radiological score that offer effective evaluation of sinusitis. The aim of this work was to revise the radiological classification of frontal air cells by B&K and to correlate it with the clinic-radiological LMS scoring system. Methods and resultsThis study was carried out on 200 sides divided into two equal groups. Three types were added to the original B&K description; Type 0 (Not identified frontal cells), Combined type and Couldn't be assessed type. The percentages of each type were calculated according to modified B&K classification and correlated to LMS. ConclusionsThe main limitation of the original B&K classification system is to accurately classify frontal air cells in cases with extensive opacification of the frontal sinus (LMS 2) as well as in cases of complicating sino-nasal polyposis. Three new types are suggested to be added to the original B&K classification system.