Anatomical variations of the frontal sinus drainage pathway and its related factors on high-resolution computed tomography: prevalence patterns and implications

The extensive adoption of functional endoscopic sinus surgery necessitates a clear understanding of nasal cavity and paranasal sinus anatomy. The frontal sinus drainage pathway displays the most complex anatomy of these areas. This study aimed to explore anatomical variations of the frontal sinus drainage pathway within a South African population, focusing on variations in frontal sinus drainage patterns, superior attachments of the uncinate process and frontal recess pneumatization patterns. Eighty-six frontal sinus drainage pathways were analyzed using computed tomography scans (bilateral analyses). The frontal sinus drained anteromedial to the uncinate process and directly into the middle meatus in 52.3% of cases; and posterolateral to the uncinate process and into the ethmoidal infundibulum in 47.7%. The superior attachment of the uncinate process was the lamina papyracea in 52.3% of cases, skull base in 38.4%, and middle turbinate in 9.3%. Agger nasi cells were the most frequently observed frontal recess cells (95.3%), followed by supra bulla cells (57.0%). Supraorbital ethmoid cells were observed least frequently (15.1%). Detailed preoperative analyses of the frontal sinus drainage pathway that highlight its drainage pattern, the uncinate process’ superior attachment and the frontal recess’ pneumatization pattern are vital because of their extensive variations. The present study advocates for description of the frontal recess pneumatization pattern using the International Frontal Sinus Anatomy Classification system. Anatomical knowledge gained from this study can be applied to surgical procedures to improve preoperative planning and ensure good postoperative results.