Accessory Maxillary Ostia: Prevalence of an Anatomical Variant and Association with Chronic Sinusitis

INTRODUCTION: The role of the accessory maxillary ostium, a common anatomical variant, in the development of chronic sinusitis remains unclear. This study aimed to examine the association between chronic sinusitis and presence of an accessory maxillary ostium using computed tomography (CT) of the paranasal sinuses. METHODS: We conducted a retrospective study of 1188 paranasal sinus CT scans performed in a major tertiary medical center between January 1, 2016 and December 31, 2016. Axial and coronal and views were reviewed to evaluate the presence of accessory maxillary ostia and maxillary and ethmoid sinusitis. RESULTS: Nine hundred twenty-eight patients were included for analysis. A 52.8% were male. Mean patient age was 33.8 years. A right accessory maxillary ostium was detected in 274 patients (29.5%), which was the same number of patients with a left accessory maxillary ostium. Bilateral accessory maxillary ostia were found in 172. The presence of right maxillary sinusitis was significantly associated with male gender and the presence of a right accessory maxillary ostium. Male gender was the only factor significantly associated with the presence of left sinusitis. Left or right ethmoidal sinusitis was significantly associated with male gender and the presence of left or right maxillary sinusitis, respectively. CONCLUSION: The presence of an accessory maxillary ostium may contribute to the development of maxillary and ethmoidal sinusitis. Further studies are needed to elucidate this association and determine indications for incorporating the natural and accessory ostia when performing middle meatus antrostomy during endoscopic sinus surgery.