Comparison of functional and anatomical parameters in patients with nasal obstruction: peak nasal inspiratory flow and computed tomography-based internal nasal valve angle.

objectiveThe internal nasal valve (INV) is the narrowest segment of the nasal airway and plays a key role in nasal airflow resistance. This study aimed to evaluate the relationship between peak nasal inspiratory flow (PNIF), bilateral INV angles measured on computed tomography (CT), and nasal examination findings in patients presenting with nasal obstruction.

methodsThis retrospective cross-sectional study included 94 patients who presented with nasal obstruction to the otorhinolaryngology outpatient clinic between January 2024 and September 2025. All patients underwent detailed nasal examination and septal deviation was classified according to the Baumann classification. Bilateral INV angles were measured on coronal paranasal sinus CT images. PNIF values were obtained from medical records. Statistical analyses were performed to assess correlations and group differences.

resultsThe mean PNIF value was 68.1 ± 24.7 L/min, and the mean bilateral INV angle was 11.2 ± 3.2°. A moderate, significant positive correlation was observed between PNIF values and bilateral INV angles (rho = 0.290, p = 0.005). Patients with a bilateral INV angle below 9° had significantly lower PNIF values compared with those with angles ≥ 9° (p = 0.011). No significant differences in PNIF values or INV angles were found among different Baumann septal deviation subtypes.

conclusionNarrower INV angles are associated with reduced functional nasal airflow as measured by PNIF. Assessment of the INV provides additional functional insight beyond septal deviation classification alone. PNIF represents a practical, noninvasive tool for functional evaluation of nasal obstruction and may support clinical decision-making and surgical planning.