Tomographic Evaluation of Temporal Bone Pneumatisation with Sinus Variations

Background/Objectives: Temporal bone pneumatisation and paranasal sinus variations have mostly been studied separately. This study evaluated temporal bone pneumatisation with frontal, ethmoid and sphenoid sinus variations using cone-beam computed tomography (CBCT) and investigated relationships among these structures. Methods: In this retrospective cross-sectional study (ethics approval no. 2025/58), 88 CBCT scans of patients aged ≥25 years were analysed. Temporal bone pneumatisation, frontal sinus size, International Frontal Sinus Anatomy Classification (IFAC) cells, ethmoid variants and sphenoid sinus pneumatisation were categorised using established classifications. Bilateral concordance and age-, sex- and inter-regional associations were tested with false discovery rate (FDR) correction, and exploratory Firth regression and multiple correspondence analysis were performed. Results: The sample comprised 49 females and 39 males (mean age 41.6 ± 13.3 years). Bilateral concordance was good for supra-bulla (κ = 0.76), supraorbital ethmoidal (κ = 0.61) and agger nasi cells (κ = 0.60) and moderate for temporal pneumatisation (κw = 0.56). The frontal sinus was larger on the left side (FDR-adjusted p = 0.002). No age-, sex- or inter-regional association survived FDR correction. In exploratory regression, male sex was associated with frontal septal cells (adjusted odds ratio [ORadj] = 3.75, 95% CI 1.36–11.15) and right supraorbital ethmoidal cells (ORadj = 3.48, 95% CI 1.35–9.62). Multiple correspondence analysis revealed no single dominant dimension. Conclusions: Temporal bone and paranasal sinus pneumatisation showed marked bilateral concordance, but no inter-regional association survived correction for multiple testing. The sex differences in frontal septal and supraorbital ethmoidal cells are hypothesis-generating and need confirmation in larger samples.