Objective diagnosis of internal nasal valve collapse by four‐phase rhinomanometry

Quantitative measurement of the flow depending nasal valve function by elastography with electro-optical distance sensors. A pilot study

Nasal valve function depends on the intensity of the inspiratory nasal airflow, the geometry of the nasal entrance and the mechanical properties of the lateral nasal wall. It is desirable to obtain objective information on the relation between flow and valve movement. In this study, the deflection of the lateral nasal wall and the inspiratory flow were measured on 30 healthy volunteers, aged 18 to 82 without a history of severe trauma or nasal surgery. Electro-optical distance sensors were housed under a full-face protective mask attached to an analogue inspiratory flowmeter. The mean values for normal breathing were assessed at 675 [cm3/s] for the bilateral flow and -0.57 mm for the total movement. With forced breathing, the mean values for the flow of both nostrils were found to be 1434 cm3/s and for the total movement -1.21 mm. Statistically significant differences between normal and forced breathing were found in all participants and in both sexes, but no significant correlation by age. Electro-optical distance measurement, representing a novel technical way for the 'elastography' of the nasal valve should be added to advanced 4-phase-rhinomanometers.

Internal Nasal Valve Collapse Treatment by Endonasal Hyaluronic Acid Injection

OBJECTIVE

Internal nasal valve collapse (IVC) is a common functional complication of rhinoplasty and injecting hyaluronic acid is one of the treatment options available, but its effectiveness has never been evaluated. The objective of this study was to assess the evolution of IVC after injection of hyaluronic acid using objective and subjective measures of nasal obstruction.

STUDY DESIGN

A prospective interventional study was conducted.

METHODS

Adult patients consulting for nasal obstruction after (septo)rhinoplasty and diagnosed with IVC were included. Patients underwent 4-phase rhinomanometry, completed nasal obstruction symptoms evaluation (NOSE) and visual analog scale (VAS) questionnaires and received hyaluronic acid injections. Measurements were repeated immediately, one month and one year later. The primary outcome measure was the proportion of patients below the rhinomanometric diagnostic threshold for IVC at one month.

RESULTS

Among the 22 patients included, 20 (91%) had rhinomanometry measurements below the diagnostic threshold for IVC one month after injection. It decreased to 53% (8/15 patients) at one year post injection. The mean NOSE score decreased from 74.5 (± 18.0) before injection to 35.2 (± 23.3) after injection (p < 0.0001). The mean VAS score decreased from 7.0 (± 1.4) before injection to 3.4 (± 1.9) after injection (p < 0.0001). In these patients with post-(septo)rhinoplasty IVC, hyaluronic acid injection into the internal nasal valve substantially improved subjective and objective measures of nasal obstruction.

CONCLUSION

These results suggest hyaluronic acid injection (performed as described) is an effective treatment for IVC and is an excellent alternative to surgical treatment.

LEVEL OF EVIDENCE III

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors https://www.springer.com/00266 .

Measurement of Nasal Obstruction: Rhinomanometry as Basic Method in Functional Rhinology

Measuring nasal obstruction should be mandatory before every nasal surgery to determine the necessary surgical steps and to separate mucosal congestion from skeletal deformity. Rhinomanometry is considered the "golden standard" for measuring nasal airway resistance. An extension of the diagnostic power was achieved by the introduction of the four-phase rhinomanometry (4PR), which provides additional information about the influence of the elasticity of the nasal wall. Also, a high correlation to the subjective sensing of obstruction could be achieved by the introduction of logarithmic parameters. The parameters of 4PR could be classified by evaluating 36,500 measurements. The International Standardization Committee on the Objective Assessment of the Upper Airway (ISCOANA) determined it as the new standard. Adding a visual analog scale (VAS) to every measurement is a documentation of the feeling of obstruction at the moment of measurement. Practical hints for 4PR are given. The determination of obstruction for both nasal sides or the calculation of the total nasal resistance should be followed by a second analysis of the detailed obstruction anatomy. In the future, pressure losses or temperature gradients can be determined by computational fluid dynamics (CFD). A reliable way to simulate the success of single surgical steps with a high didactical meaning is the three-dimensional (3D) print of sliced nose models and to measure the effect of stepwise mechanical corrections.

Elastometry - The biomechanical analysis of the lateral nasal wall

'Elastometry' is a novel technique that allows for the quantitative assessment of elastic properties of the nasal tissues, providing valuable insights into the dynamic behavior of the external, soft lateral nasal wall. This study aimed to explore the application of 'elastometry' in understanding the biomechanics of the lateral nasal wall and its implications for nasal function in 'elastometry' measurements. After validation of safety and reliability of this method, we investigated mechanical properties of the lateral nasal wall by 'elastometry' using specifically developed measurement forceps with end pieces including sensors applied on 30 healthy volunteers, aged 18 to 82 without a history of severe trauma or surgery. By measuring normal stress and path length between the end pieces the modulus of elasticity was calculated. Among 360 measurements, the mean value determined for healthy female volunteers was E = 0.135 [N/mm2] and for healthy males E = 0.169 [N/mm2], fitting the range reported in the literature. A tendency of an age-related degree of elastic behavior of the lateral nasal wall was observed, whereby a decrease in elasticity with age in female and a slight increase in elasticity with age in male was detected. Our research showed that 'elastometry' is a cost and time-efficient method to calculate the modulus of elasticity, and could be used in conjunction with 4-phase rhinomanometry (4 PR) to extend diagnostic yield.

Economic impact analysis of a minimally invasive temperature-controlled radiofrequency device versus nasal surgery for the treatment of nasal airway obstruction in the United States

OBJECTIVE

To determine the economic impact of a minimally invasive temperature-controlled radiofrequency (TCRF) device for treating nasal airway obstruction (NAO).

METHODS

A budget impact model was developed for two scenarios: a reference scenario of functional rhinoplasty surgery with concomitant septoplasty and inferior turbinate reduction (ITR) performed in the hospital outpatient department where TCRF is not an available treatment option and a new scenario consisting of in-office TCRF treatment of the nasal valve and ITR. A payor perspective was adopted with a hypothetical population plan size of one million members. Costs were estimated over a time horizon of 4 years. The eligible population included patients with severe/extreme NAO and nasal valve collapse (NVC) as the primary cause or significant contributor. Data inputs were sourced from targeted literature reviews. Uncertainty within the model structure and input parameters was assessed using one-way sensitivity analysis.

RESULTS

The introduction of a TCRF device resulted in population-level cost savings of $20,015,123 and per-responder average cost savings of $3531 through a 4-year time horizon due to lower procedure costs and complication rates of the device relative to the surgical comparator. Results were robust when varying parameter values in sensitivity analyses, with cost savings being most sensitive to the prevalence of NAO and estimated response rates to functional rhinoplasty and TCRF.

CONCLUSIONS

In patients with severe/extreme NAO, with NVC as the primary or major contributor, introducing TCRF with ITR as a treatment option demonstrates the potential for significant cost savings over functional rhinoplasty with septoplasty and ITR.

Changes in nasolabial angle may alter nasal valve morphology and airflow: a computational fluid dynamics study

Aim: Nasal valve (NV) dysfunctions are a significant cause of nasal obstruction. Changes in the nasolabial angle (NLA) may also cause changes in NV morphology. The effect of changes in the 3D structure of the nasal valve region (NVR) on nasal airflow has yet to be studied sufficiently. The accuracy of computational fluid dynamics (CFD) simulation results of nasal airflow has been confirmed by in vitro tests. Therefore, this study aimed to evaluate the effect of changes in NV structure and volume on nasal airflow based on the CFD method. Material and Method: We used CT images to create a 3D structural model of the NVR. First, CT images were transferred to MIMICS® software, and the nasal air passage was modeled. A solid reference model of the NVR was then created using SolidWorks software. Five different solid 3D nasal valve models were created with nasolabial angles of 85˚ in Model 1, 90˚ in Model 2, 95˚ in Model 3, 100˚ in Model 4, and 105˚ in Model 5. To simulate breathing during rest and exercise using the CFD method, the unilateral nasal airflow rates were set at 150 ml/s and 500 ml/s, respectively. The CFD method was then used to calculate each model’s airflow properties. Finally, the volumes of the models, pressure at the NV outlet, and airflow velocity were evaluated and calculated to investigate each model’s NV airflow characteristics. Results: Our study found a significant correlation between the nasolabial angle (NLA) and NVR volume (r=-0.998, p=0.000), flow rate and velocity (r=0.984, p=0.000), velocity and maximum pressure (r=0.920, p=0.000), velocity and minimum pressure (r=-0.969, p=0.000), flow rate and maximum pressure (r=0.974, p=0.000), and flow rate and minimum pressure (r=-0.950, p=0.000). There was no correlation between NLA increase and nasal airflow velocity. We determined that the highest pressure and lowest airflow velocity values were in the upper angle region and that the lowest pressure and highest airflow velocity values were at the bottom of the NVR in all models. Conclusion: Using the CFD method, we found a decrease in NVR volume and an increase in airflow velocity with an increase in NLA. In addition, we found that the pressure values in the NVR did not change significantly with the increase in NLA.