Three-dimensional computed tomography analysis of frontoethmoidal cells: A critical evaluation of the International Frontal Sinus Anatomy Classification (IFAC).

Objectives: Two major classifications of frontoethmoidal cells, Lee and Kuhn and the IFAC (International Frontal Sinus Anatomy Classification), distinguish anterior, posterior and medial cells. The European anatomical position paper includes also lateral cells. According to the IFAC, anterior cells push the frontal sinus drainage pathway (FSDP) medially, posteriorly or posteromedially. Posterior cells push the FSDP anteriorly. The only medial cell, pushing the FSDP laterally is the frontal septal cell, which is attached to or located in the interfrontal sinus septum. The aim of this study was to verify the IFAC and characterise cells, which are inconsistent with this classification.

Design: A radioanatomic analysis.

Setting: Tertiary university hospital.

Participants: One hundred and three Caucasian adult patients with no inflammatory changes in paranasal sinuses CT.

Main Outcomes Measure: Results of assessment of multiplanar reconstruction of thin slice CT.

Results: Two types of cells that cannot be classified using the IFAC were found: (a) Lateral cells extending between the skull base and the anterior buttress, pushing the FSDP anteromedially or medially, present in 34 (16.5%) of the sides, (b) Paramedian cells: medially based, not adjacent to the interfrontal septum, pushing the FSDP laterally and posteriorly, present in 33 (16%) of sides. Suprabulla cells and suprabulla frontal cells were found to push the FSDP in directions other than anterior 28% and 31% of the time respectively.

Conclusions: Neglecting lateral and paramedian cells may lead to inconsistent results between radioanatomical studies and impede communication between surgeons. They should be included in existing classifications of frontoethmoidal cells.