Incidence of anatomical variations according to the International Frontal Sinus Anatomy Classification (IFAC) and their coincidence with radiological sings of opacification

Abstract

BackgroundThe endonasal access to the frontal recess and sinus may be complicated by a variety of anatomical variations. Previous classifications of these variants were characterized by proper names or position information without anatomical reference. The IFAC is intended to simplify the classification of anatomical variations of the frontoethmoidal complex. The aim of this study was to analyse a representative number of sinus CT scans to assess the incidence of anatomical variations according to the IFAC and to compare the results with previous classifications. In addition, the coincidence of complex anatomical variations and radiological sings of opacification was investigated. Methodology/principal Two hundred and forty-nine sinus CT scans were analysed in multiplanar reconstructions. Exclusion criteria were previous operations on the paranasal sinuses, malignant diseases, and an insufficient image quality. All anatomical variants were analysed according to the IFAC criteria. In addition, the coincidence of radiological sings of opacification and the presence of anatomical variations of the frontal recess and sinus were investigated. ResultsThe analysis revealed Agger nasi cells in 95% of the CT scans. Supra agger cells (SACs) were detected in 49% and Supra agger frontal cells (SAFCs) in 25% of the data sets. Suprabulla cells (SBCs) were detected in 89% and Supra bulla frontal cells (SBFCs) in 27% of the scans. Supraorbital ethmoid cells (SECs) were detectable in 9% and interfrontal septal cells in 28% of the scans. Despite a partially strong narrowing of the frontal recess, no increased occurrence of radiological sings of opacification could be detected (p > 0.05). Conclusions Anatomical variations in the frontoethmoidal area are very common. According to the IFAC criteria, in 43% of the patients, cells could be detected with pneumatization to or into the frontal sinus. The IFAC is structured more clearly compared to previous classifications due to the anatomical aspect. It represents the most consistent classification regarding surgical planning. Further studies will demonstrate the scientific and clinical value of this classification.

Computed tomographic analysis of the prevalence of International Frontal Sinus Anatomy Classification cells and their association with frontal sinusitis

“…This is comparable to published findings, which range from 89 per cent to 94 per cent. 3,9 In a study by Choby et al . 10 on a North American population and a study by Tran et al .…”

“…However, only one study in the literature investigated the association of International Frontal Sinus Anatomy Classification cells with frontal sinusitis. 9…”

“…This is comparable to published findings, which range from 89 per cent to 94 per cent. 3,9 In a study by Choby et al 10 on a North American population and a study by Tran et al 11 on a Vietnamese population, where the fronto-ethmoidal cells were categorised according to the International Frontal Sinus Anatomy Classification, the prevalence rates of agger nasi cells were 96.5 per cent and 95.7 per cent respectively. The consistent presence of agger nasi cell is the primary reason why this cell is used as a reference cell for all the anteriorly based cells in the International Frontal Sinus Anatomy Classification system.…”

“…Sommer et al demonstrated no increased occurrence of frontal sinus opacification associated with the presence of International Frontal Sinus Anatomy Classification cells ( p > 0.05). 9 Meyer et al categorised the cells according to the Bent and Kuhn classification and found a higher incidence of frontal sinusitis in patients with frontal cell types 3 and 4. 7 DelGaudio et al also classified the cells according to the Bent and Kuhn classification 1 and reported no significant difference in the frequency of frontal sinusitis for patients with or without agger nasi cells or frontal cells.…”

Anatomical Predictions of Development of Rhinosinusitis and Its Complications

“…The anatomical structure of the frontal sinus is also of great importance for development of inflammatory pathological processes [6] and their complications with spread to the neighboring organs and tissues (orbital phlegmon, brain abscess, meningitis). Pathological processes occurring in the frontal sinus due to its topographic and anatomical relationships with nearby structures most often lead to complications.…”