Objectives 1. Quantify mucosal cooling (i.e., heat loss) spatially in the nasal passages of nasal airway obstruction (NAO) patients before and after surgery using computational fluid dynamics (CFD). 2. Correlate mucosal cooling with patient-reported symptoms, as measured by the Nasal Obstruction Symptom Evaluation (NOSE) and a visual analog scale (VAS) for sensation of nasal airflow. Study Design Prospective Setting Academic tertiary medical center. Subjects and Methods Computed tomography (CT) scans and NOSE and VAS surveys were obtained from 10 patients before and after surgery to relieve NAO. Three-dimensional models of each patient’s nasal anatomy were used to run steady-state CFD simulations of airflow and heat transfer during inspiration. Heat loss across the nasal vestibule and the entire nasal cavity, and the surface area of mucosa exposed to heat fluxes > 50 W/m2 were compared pre- and post-operatively. Results After surgery, heat loss increased significantly on the pre-operative most obstructed side (p values < 0.0002). A larger surface area of nasal mucosa was exposed to heat fluxes > 50 W/m2 after surgery. The best correlation between patient-reported and CFD measures of nasal patency was obtained for NOSE against surface area in which heat fluxes > 50 W/m2 (Pearson r = −0.76). Conclusion A significant post-operative increase in mucosal cooling correlates well with patients’ perception of better nasal patency after NAO surgery. CFD-derived heat fluxes may prove to be a valuable predictor of success in NAO surgery.

Atrophic rhinitis is a chronic disease of the nasal mucosa. The disease is characterized by abnormally wide nasal cavities, and its main symptoms are dryness, crusting, atrophy, fetor, and a paradoxical sensation of nasal congestion. The etiology of the disease remains unknown. Here, we propose that excessive evaporation of the mucous layer is the basis for the relentless nature of this disease. Airflow and water and heat transport were simulated using computational fluid dynamics (CFD) techniques. The nasal geometry of an atrophic rhinitis patient was acquired from computed tomography scans before and after a procedure to narrow the nasal cavity. Simulations of air conditioning in the atrophic nose were compared with similar computations performed within the nasal geometries of four healthy humans. The excessively wide cavity of the patient generated abnormal flow patterns, which led to abnormal patterns of water fluxes across the wall. Geometrically, the atrophic nose had a much lower surface area than the healthy nasal passages, which increased water fluxes per unit area. Nevertheless, the simulations indicated that the atrophic nose did not condition inspired air as effectively as the healthy geometries. These simulations of water transport in the nasal cavity are consistent with the hypothesis that excessive evaporation of mucus plays a key role in the pathophysiology of atrophic rhinitis. We conclude that the main goals of a surgery to treat atrophic rhinitis should be 1) to restore the original surface area of the nose, 2) to restore the physiological airflow distribution, and 3) to create symmetric cavities.

Surgeries to correct nasal airway obstruction (NAO) often have less than desirable outcomes, partly due to the absence of an objective tool to select the most appropriate surgical approach for each patient. Computational fluid dynamics (CFD) models can be used to investigate nasal airflow, but variables need to be identified that can detect surgical changes and correlate with patient symptoms. CFD models were constructed from pre- and post-surgery computed tomography scans for 10 NAO patients showing no evidence of nasal cycling. Steady-state inspiratory airflow, nasal resistance, wall shear stress, and heat flux were computed for the main nasal cavity from nostrils to posterior nasal septum both bilaterally and unilaterally. Paired t-tests indicated that all CFD variables were significantly changed by surgery when calculated on the most obstructed side, and that airflow, nasal resistance, and heat flux were significantly changed bilaterally as well. Moderate linear correlations with patient-reported symptoms were found for airflow, heat flux, unilateral allocation of airflow, and unilateral nasal resistance as a fraction of bilateral nasal resistance when calculated on the most obstructed nasal side, suggesting that these variables may be useful for evaluating the efficacy of nasal surgery objectively. Similarity in the strengths of these correlations suggests that patient-reported symptoms may represent a constellation of effects and that these variables should be tracked concurrently during future virtual surgery planning.

In the model, anterior septal deviations increased nasal resistance more than posterior deviations. This suggests, in agreement with the literature, that other causes of nasal obstruction (dysfunction of the nasal valve, allergy, etc.) should be carefully considered in patients with posterior septal deviations because such deviations may not affect nasal resistance. This study illustrates how computational modeling and virtual manipulation of the nasal geometry are useful to investigate nasal physiology.

Importance-A gold standard objective measure of nasal airway obstruction (NAO) does not currently exist, so patient-reported measures are commonly used, particularly the Nasal Obstruction Symptom Evaluation (NOSE) and the visual analog scale (VAS). However, questions remain regarding how best to utilize these instruments.Objectives-The goal of this study is to systematically review studies on NOSE and VAS scores in NAO patients and compile and standardize the data to (1) define symptomatic and normative values for (a) pre and post-surgical NAO patients, (b) asymptomatic individuals, and (c) the general population, (2) determine if post-surgery scores are comparable to asymptomatic scores, and (3) determine if there is a clinically useful pre-operative and post-operative score change.Evidence Review-A systematic review of the literature was performed through PubMed for studies assessing NOSE and VAS scores in patients with chronic NAO. Strict inclusion criteria were applied to focus on anatomic obstruction only. For statistical analysis, the patients were divided into asymptomatic, pre-and post-surgery NAO, and the general population.Findings-The average NOSE and VAS scores for a patient with NAO were 65 ± 22 and 6.9 ± 2.3 respectively. The average post-surgery NOSE score was 23 ± 20 and VAS score was 2.1 ± 2.2. The average asymptomatic individual NOSE score was 15 ± 17, and VAS score was 2.1 ± 1.6.