Effect of an intra-oral nasal dilation appliance on 3-D nasal airway morphology in adults.

To determine the effects of a nasal dilation appliance on 3-D nasopharyngeal airway patency. The sample comprised 187 adults (98 males, 89 females) with a history of sleep-disordered breathing. Acoustic rhinometry readings were taken from all patients before and after the intra-oral placement of a nasal dilation appliance (OASYS). The mean left and right nasopharyngeal airways were reconstructed in 3-D, and the data from the right and left nostrils were subjected to principal components analysis (PCA) and finite-element scaling analysis (FESA). Comparing the pre- and post-treatment 3-D mean, left nasopharyngeal airways using PCA, the first two eigenvalues accounted for 96% of the total shape change, and statistical differences were found (p < 0.01). Similarly, for the right side, significant differences were detected between the mean pre- and post-treatment 3-D nasopharyngeal airways (p < 0.01) using PCA. Using FESA to quantify and localize changes after the placement of the nasal dilation appliance, the 3-D mean, normalized, left nasopharyngeal airway was found to be 14% wider in the anterior nasal valve region and 28% wider in the distal regions, while the 3-D mean, normalized, right nasopharyngeal airway was 13% wider in the anterior nasal valve region and 27% wider further distally. The use of an intra-oral nasal dilation appliance may be useful in the management of nasopharyngeal conditions, such as snoring, upper airway resistance syndrome, sleep-disordered breathing, and obstructive sleep apnea, especially in cases where nasal obstruction is demonstrable.