Correlation between the Level of Maximum Airway Obstruction by Flexible Naso-pharyngo-laryngoscopy Examination and Severity of Obstructive Sleep Apnea Syndrome Using Polysomnography

Purpose: To assess the correlation between the level and grade of maximum airway obstruction by flexible naso-pharyngo-laryngoscopy examination (FNPL) and the severity of obstructive sleep apnea syndrome (OSAS) using polysomnography.Methods: A cross-sectional study was conducted on 33 patients diagnosed with OSAS with polysomnography. A FNPL using Müller’s maneuver was performed for every patient with its findings evaluated according to the Nose Oropharynx Hypopharynx and Larynx (NOHL) classification. The study assessed the correlation between the grades of obstruction at different levels and the apnea-hypopnea index (AHI) and the significance of the effect of the grade of obstruction at each level on the AHI.Results: The grades of nasal obstruction, retrolingual obstruction, and tonsillar hypertrophy had a significant positive correlation with the AHI (p = 0.0052, 0.0012, and 0.00169, respectively). Moreover, BMI and the grade of retropalatal obstruction had a highly substantial positive correlation with AHI (p = 0.00004 and 0,00003, respectively). Multiple regression analysis revealed that retropalatal obstruction was the only factor having a significant individual effect on the grade of sleep apnea (p = 0.04).Conclusion: Flexible Naso-Pharyngo-Laryngoscopy examination is an essential assessment step for OSAS patients with Müller’s maneuver being the most available and safest method. In the present study, this assessment showed that OSAS had a multilevel obstructive etiology with a positive correlation between the grade of obstruction at each level and AHI indicating the severity of OSAS. Regression analysis showed that retropalatal obstruction was the significant individual factor affecting AHI.