[Association between subjective nasal patency and airflow characteristics of nasal cavity on nasal septum deviation]

Objective:To investigate the pre- and post-operative intranasal airflow characteristics on nasal septum deviation and the correlation between subjective nasal patency and airflow characteristics by numerical simulation. Method:Forty-two nasal septum deviation cases were enrolled in this study. Pre- and post-operative VAS score of subjective nasal patency were recorded. We created computational fluid dynamics (CFD) nasal cavity airway models based on computed tomography and investigated the pre- and post-operative intranasal airflow characteristics. Result:Postoperative subjective nasal patency on patients with septal deviation showed significant improvement than preoperative (P<0.01). The intranasal airflow on deviated side nasal cavity increased from preoperative (34.94±14.82)% to postoperative (47.67±3.58)% (P<0.01). The parameters of ΔP（anterior inferior turbinate）,ΔT（anterior inferior turbinate） and ΔT（posterior end of the septum）decreased significantly from preoperative (7.657±4.839)Pa to postoperative (4.500±2.403)Pa，preoperative (8.482±1.767)K to postoperative （7.096±1.127）K，and preoperative (11.386±0.505）K to postoperative （10.895±0.736）K respectively (P<0.01). The value of NR₁ decreased from (0.043±0.021) Pa•s/ml to (0.038 0±0.016) Pa•s/ml, showed statistically significant difference (P<0.05), but the value of NR₂ decreased from (0.071 0±0.035)Pa•s/ml to (0.061 5±0.048) Pa•s/ml, showed no statistically significant difference (P>0.05). The related degree of subjective nasal patency VAS score on ΔT（anterior inferior turbinate） and intranasal airflow of deviated side nasal cavity are higher (R²=0.619 6 and R²=0.508 7）than ΔP（anterior inferior turbinate）and NR₂（R²=0.326 7 and R²=0.298 1）.It suggested that there is no correlation between subjective nasal patency VAS score and ΔT（posterior end of the septum），NR₁ (R²=0.0451 and R²=0.0721). Conclusion:It showed different pressure and temperature gradient in bilateral nasal cavity of nasal septal deviation. The septoplasty improved the patient's feeling of subjective nasal patency, and recovered the balance of the airflow distribution on bilateral nasal cavity. By correlation analysis, we concluded that nasal resistance could not represent the severity of subjective nasal patency, but the intranasal airflow showed good correlations with subjective nasal patency, especially the temperature drop in mucous membrane at the nasal front end is more sensitive to reflect subjective nasal patency feeling.