The influence of the size of the maxillary sinus ostium on the nasal and sinus nitric oxide levels

Background: Nitric oxide (NO) is produced in significant quantities in the nasal sinuses and is thought to have a beneficial effect on the mucociliary transport of the sinuses and nose and to have significant antibacterial properties that contribute to the health of the sinuses. Recently, the concept of "mini-functional endoscopic sinus surgery" has been introduced where the uncinate is removed without enlargement of the maxillary ostium. Although no scientific evidence has been published, enlargement of the ostium is thought to possibly disrupt the mucociliary pathway and decrease the concentration of NO in the nose and sinuses. The aim of this study was to establish the effect of enlargement of the maxillary ostium on sinus and nasal NO. Methods: Twenty-nine patients who were post-endoscopic sinus surgery were included with 52 who were maxillary sinus ostia cannulated. There were 22 large maxillary sinus ostia and 30 small ostia. Smoking, allergy status, and topical steroid use were recorded. NO levels were measured in the nose and maxillary sinus after decongestion with patients mouth breathing and breath holding. Results: This study shows that enlargement of the maxillary sinus ostium above its normal size (20 mm(2)) produces a significant decrease in both the maxillary sinus and the nasal cavity NO levels. In addition, the size of the ostium showed a significant correlation to the sinus NO level. Use of topical nasal steroid sprays and topical decongestants were shown to effect NO levels in the sinuses and nasal cavity. The lowered levels of NO were found irrespective of the technique of measurement of the NO. Conclusions: The effect of this lowered NO level on the susceptibility of the maxillary sinuses to recurrent infection is yet to be determined.