Variations of maxillary sinus and accompanying anatomical and pathological structures

Hypoplasia and aplasia of maxillary sinus, maxillary sinus septae, ethmomaxillary sinus, superior meatus-draining maxillary sinus, and over-pneumatization are the variations of maxillary sinuses. Findings such as uncinate process abnormality, orbital enlargement, sphenomaxillary plate, canine fossa elevation, infraorbital fissure enlargement, thickening of the sinus wall and mucosal pathologies can be seen together with these variations. The aim of this study is to determine the incidence and morphology of the anatomical variations of maxillary sinus and accompanying structures. A total of 330 consecutive paranasal sinus computed tomography scans of the patients presenting with sinonasal complaints at our ENT department were assessed for maxillary sinus anatomical variations and related structures. There were 134 (20.3%) anteriorly and 17 (2.5%) posteriorly localized maxillary sinus bony septa. The position of antral septa was frequently vertical at anterior, and horizontal at posterior. We found significant correlation between the anteriorly localized maxillary sinus septa and infraorbital fissure enlargement. Maxillary sinus hypoplasia was found in 31 (4.6%) maxillary sinuses. Seven (1.0%) ethmomaxillary sinuses were assessed. Significant correlation was found between maxillary sinus hypoplasia and orbital enlargement. Presence of mucosal pathology was significant in patients with maxillary sinus septa, but there was no difference when it was compared with the mucosal pathology in the nonseptated group. There was no significant correlation between other anatomical variations and mucosal pathologies. Determining the anatomical variations of maxillary sinus and accompanying structures in patients planning endoscopic sinus surgery will significantly help with providing surgical orientation and preventing possible complications.