The performance of a maxillary antrostomy through the natural ostium of the maxillary sinus has been debated in the literature over the years. However, much of the argument against middle meatal antrostomy has been based primarily upon animal studies in which there was a patent maxillary sinus ostium. A detailed study was therefore undertaken to evaluate the effects of both ostioplasty and nasal antral window in an animal model with maxillary sinus ostial obstruction. Twenty Pasteurella-free White New Zealand Rabbits underwent unilateral ostial occlusion with Histoacryl®. The sinuses were reexplored after 2 weeks. In 10 sinuses a nasal antral window was performed. In the remaining 10, two variations of ostioplasty were performed. Half underwent circumferential widening by removal of the root of the middle turbinate and half underwent a limited antero-inferior widening of the ostium. The opposite maxillary sinus in each animal was kept as a control. A second exploration was performed at 6 weeks. Significant evidence of inflammation was not found in any of the sinuses with limited widening of the maxillary sinus ostium, but was present in 10% of the sinuses with nasal antral windows and 40% of the sinuses with circumferential ostial widening. Normal mucociliary clearance was present in 80% of the sinuses with limited ostioplasty, 60% of the sinuses with circumferential ostioplasty, and 40% of those with nasal antral window. These findings support the clinical observation that limited widening of the natural ostium of the maxillary sinus is an effective treatment for inflammation secondary to ostial obstruction. However, they also suggest that circumferential widening of the maxillary sinus ostium, at least in the short term, predisposes to infection.
Unusual Appearance of the Maxillary Sinus Ostium on Transnasal Endoscopy