Improvements in airflow characteristics and effect on the NOSE score after septoturbinoplasty: A computational fluid dynamics analysis

Septoturbinoplasty is a surgical procedure that can improve nasal
congestion symptoms in patients with nasal septal deviation and inferior
turbinate hypertrophy. However, it is unclear which physical domains of
nasal airflow after septoturbinoplasty are related to symptomatic
improvement. This work employs computational fluid dynamics modeling to
identify the physical variables and domains associated with symptomatic
improvement. Sixteen numerical models were generated using eight
patients' pre- and postoperative computed tomography scans. Changes
in unilateral nasal resistance, surface heat flux, relative humidity, and
air temperature and their correlations with improvement in the Nasal
Obstruction Symptom Evaluation (NOSE) score were analyzed. The NOSE score
significantly improved after septoturbinoplasty, from 14.4 ± 3.6 to 4.0 ±
4.2 (p < 0.001). The surgery not only increased the airflow
partition on the more obstructed side (MOS) from 31.6 ± 9.6 to 41.9 ± 4.7%
(p = 0.043), but also reduced the unilateral nasal resistance in the MOS
from 0.200 ± 0.095 to 0.066 ± 0.055 Pa/(mL×s) (p = 0.004). Improvement in
the NOSE score correlated significantly with the reduction in unilateral
nasal resistance in the preoperative MOS (r=0.81). Also, improvement in
the NOSE score correlated better with the increase in surface heat flux in
the preoperative MOS region from the nasal valve to the choanae (r=0.87)
than in the vestibule area (r=0.63). Therefore, unilateral nasal
resistance and mucous cooling in the preoperative MOS can explain the
perceived improvement in symptoms after septoturbinoplasty. Moreover, the
physical domain between the nasal valve and the choanae might be more
relevant to patient-reported patency than the vestibule area.