Three-dimensional computed tomography analysis of frontal recess cells according to the International Frontal Sinus Anatomy Classification (IFAC) - difficulties in identification of frontal recess cells in patients with diffuse primary chronic rhinosinusitis?

Introduction: The International Frontal Sinus Anatomy Classification (IFAC) is a consensus document created to standardize and specify the naming of cells within the region of the frontal recess and frontal sinus. Aim: The aim of this study was to analyze the difficulties in identifying cells according to the IFAC in patients with diffuse primary chronic rhinosinusitis. Material and methods: Three independent reviewers examined triplanar computed tomography (CT) scans to assess the anatomy of the frontal recess using the IFAC system. CT scans were chosen randomly and divided into 3 groups: CT scans of patients not presenting sinus complaints (control group), CT scans of patients affected by diffuse primary chronic rhinosinusitis non-type 2, and CT scans of patients affected by diffuse primary chronic rhinosinusitis type 2. Results: Identification of all frontal cell types was accurate in patients not presenting sinus complaints (P-value < 0.05). Patients scoring 9 or more points in the Lund-Mackay scoring system demonstrated a statistically increased risk of improper identification of frontal recess cells (P-value < 0.0001). Conclusions: Due to a large number of possible anatomical variants and changes caused by the chronic inflammatory disease, the IFAC nomenclatura is easier to apply to non-type 2 primary diffuse CRS patients with low scores in the L-M score scale than to primary diffuse type 2 CRS patients with higher M-L scores.