The Nasal Obstruction Balance Index: A Novel Approach to Improving Correlation Between Unilateral Nasal Airway Measurements and Evaluating Nasal Airway Asymmetry

Objectives/Hypothesis Demonstrate that the Nasal Obstruction Balance Index (NOBI) model fulfils the unmet need of improving unilateral correlation between subjective and objective nasal obstruction outcome measures and identifying the more obstructed side. Improve correlation between unilateral objective nasal airway measurements (nasal inspiratory peak flow [NIPF] and acoustic rhinometry [AR]) and subjective Visual Analogue Scale for nasal obstruction (VAS-NO) scores. Improve assessment of nasal airway asymmetry by evaluating unilateral measurements both before and after the application of nasal decongestant; which the patient could better understand. NOBI represents a ratio calculated by taking the difference between left and right nasal airway measurements and divided by the maximum unilateral measurement. It is based on Poiseuille's law and aims to reduce the confounding variables which challenge nasal airway measurement. Study Design Prospective cohort study. Methods Forty-three controls and 34 patients with nasal obstruction underwent both unilateral and bilateral NIPF, AR and VAS-NO measurements; these were repeated after the application of nasal decongestant. The NOBI values for unilateral NIPF, AR, and VAS-NO were calculated both before and after decongestant. Results The correlation between unilateral NIPF and AR measurements was enhanced considerably (r = 0.57, P < .01) when NOBI was applied. The NOBI metric significantly increased the correlation between unilateral NIPF, AR, and VAS-NO scores. Postdecongestant NOBI for NIPF and AR measurements correctly identified the more obstructed side in 82.4% and 94.1% of the deviated nasal septum (DNS) cases, respectively. Conclusion The NOBI model provides a better correlation between unilateral subjective and objective measurements and identifies the more obstructed side. Level of Evidence Prospective cohort study (level III) Laryngoscope, 2021