The cotton test redistributes nasal airflow in patients with empty nose syndrome

Summary of the Study on Nasal Airflow Redistribution in Empty Nose Syndrome (ENS) Using the Cotton Test

#### Background

Empty Nose Syndrome (ENS) is a condition that can arise after sinonasal surgery, particularly following the excessive removal of inferior turbinate tissue. Patients with ENS often experience debilitating symptoms such as a paradoxical sensation of nasal obstruction, suffocation, burning, dryness, and crusting. These symptoms can severely impact their quality of life and lead to psychosocial issues, including anxiety and depression. Despite various treatments available, including submucosal implants, there remains a lack of understanding about the exact mechanisms driving symptom relief. The cotton test, involving the placement of a cotton plug in the inferior meatus of the nose, has been observed to provide rapid symptomatic relief. However, the physiological reasons behind this improvement were not well understood until now.

#### Objective

The goal of this study was to investigate the physiological mechanisms underlying the symptomatic relief provided by the cotton test. Specifically, the researchers aimed to understand how cotton placement affects nasal airflow dynamics and resistance in patients with ENS.

#### Methods

The study involved six patients diagnosed with ENS who had previously experienced symptomatic improvement from the cotton test, evidenced by a significant reduction in their ENS6Q scores. Each patient underwent sinus computed tomography (CT) scans both before and after the placement of a cotton plug in the inferior meatus. The cotton plug was marked with iohexol contrast spray for visibility in CT imaging. Computational fluid dynamics (CFD) was then employed to analyze changes in nasal airflow patterns, resistance, and distribution resulting from the cotton placement.

#### Results

1. **Symptomatic Improvement:** Post-cotton placement, patients showed a significant reduction in ENS6Q scores, dropping from an average of 16.8 ± 4.1 to 3.1 ± 2.4 (p < 0.001). This confirms the subjective improvement reported by the patients.

2. **Nasal Resistance:** CFD analysis revealed a 21% increase in nasal resistance following cotton placement (p < 0.05). This aligns with the understanding that the presence of the cotton plug reduces nasal airflow volume due to increased resistance.

3. **Airflow Distribution:** A key finding was a significant shift in airflow distribution. Before cotton placement, airflow was predominantly directed through the middle meatus. After placement, there was a 41% decrease in airflow through the middle meatus, and airflow became more evenly distributed between the middle and inferior meatuses (p < 0.05). This shift indicates that cotton placement restores a more balanced airflow pattern.

4. **Flow Patterns and Pressure Gradient:** The airflow trajectory changed from a jetstream predominantly through the middle meatus to a more dispersed pattern that improves airflow in the inferior meatus. The pressure gradient in the nasal cavity also became smoother and more linear after cotton placement, suggesting improved nasal resistance and airflow distribution.

#### Conclusions

The study demonstrated that the cotton test effectively increases nasal resistance and alters airflow distribution in ENS patients. The significant reduction in middle meatus airflow and the increase in airflow resistance suggest that the cotton plug helps in redistributing airflow to mimic a more normal pattern, which alleviates ENS symptoms.

#### Implications

The findings validate the use of the cotton test as a diagnostic and therapeutic tool for ENS. The study highlights the importance of understanding nasal airflow dynamics and resistance in designing and implementing treatments for ENS. The insights gained from CFD analysis can help in optimizing surgical procedures, such as inferior meatus augmentation, by providing a better understanding of how airflow changes with different interventions.

Overall, this research underscores the potential of the cotton test in managing ENS and emphasizes the need for further studies to refine treatment approaches based on these physiological insights.