Correlations between Cephalometric Measures of the Upper Airways and Peak Nasal Inspiratory Flow (PNIF)

Abstract

Background: The purpose of this study was to determine the relationship between the Peak Nasal Inspiratory Flow (PNIF) and cephalometric measurements of the upper airways.
Methods: Thirty patients (15 girls and 15 boys) age range 10-15 years with no history of tonsillectomy or adenoidectomy, nasal trauma < 1 month, or pulmonary disease, were included in this cross sectional study. The PNIF was measured with the Youlten peak flow meter (Clement Clarke International, London, UK). Sagittal and vertical dimensions of the upper airways were evaluated on lateral cephalometric radiographs. The t- test was used to assess differences in PNIF and cephalometric variables between subjects grouped according to sex (male and female). Pearson's correlation coefficient was used to analyse the relationship between the cephalometric variables and the PNIF. The significance was set at P< 0.05.
Results: There were no statistically significant differences in PNIF between boys and girls. Gender differences were observed in the vertical angle of the nasopharynx (PNS-Ba-S) which is significantly greater in boys (P = 0.03). The PNIF was significantly and negatively correlated with Ad-PTV (depth (anteroposterior direction) of nasopharyngeal airway space opposite to the upper part of the adenoids) (r = - 0.41, P= 0.02) and Ad1-PNS (depth of nasopharyngeal airway space opposite to the lower part of the adenoids) (r = - 0.40, P= 0.03). Oropharyngeal and hypopharyngeal measurements had no significant correlation with PNIF airways space.
Conclusion: The Peak nasal Inspiratory flow, is only partly correlated with pharyngeal cephalometric measures obtained from lateral cephalograms. These measures of the pharyngeal duct are not suitable for the assessment of upper airways patency. Further investigation using 3-D imaging should be undertaken to ascertain the relationships between PNIF and pharyngeal dimensions.