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.

 

Computational fluid dynamic analysis of aggressive turbinate reductions: is it a culprit of empty nose syndrome?

 ### Summary of the Study: Computational Fluid Dynamics of Aggressive Turbinate Reductions and Empty Nose Syndrome

#### **Background**

Empty Nose Syndrome (ENS) is a controversial condition associated with nasal surgeries, particularly aggressive inferior turbinate reductions (ITR). Despite common knowledge that ITR aims to alleviate nasal obstruction, some patients report paradoxical symptoms like nasal dryness, pain, and obstruction post-surgery. 

#### **Objective**

This study aimed to explore the relationship between aggressive ITR and ENS by analyzing nasal airflow dynamics and mucosal sensory function in patients who had undergone ITR. The goal was to identify specific factors that might contribute to the development of ENS.

#### **Methods**

- **Study Design**: The research involved a comparative analysis using computational fluid dynamics (CFD) based on CT scans of the nasal cavity.

- **Participants**: 

  - **Aggressive ITR without ENS Symptoms**: 5 patients who had undergone aggressive ITR but showed no ENS symptoms.

  - **Symptomatic ENS**: 27 patients with documented ENS symptoms post-ITR.

  - **Healthy Controls**: 42 individuals with no nasal issues.

- **Evaluations**:

  - **CFD Analysis**: Compared airflow dynamics, cross-sectional areas, and nasal resistance among the groups.

  - **Questionnaires**: Utilized SNOT-22, NOSE, and ENS6Q to assess nasal symptoms and quality of life.

  - **Trigeminal Function**: Measured through menthol lateralization detection thresholds (LDTs) to assess sensory function.

#### **Results**

1. **Nasal Airflow and Resistance**:

   - Both aggressive ITR patients without ENS and symptomatic ENS patients had lower nasal resistance and larger cross-sectional areas around the inferior turbinate compared to healthy controls. 

   - However, ENS patients exhibited significantly less airflow in the inferior meatus but more airflow in the middle meatus compared to both healthy controls and aggressive ITR patients without symptoms.

   - This imbalance in airflow distribution suggests altered nasal aerodynamics in ENS patients.

2. **Wall Shear Stress**:

   - ENS patients had significantly lower wall shear stress in the inferior meatus, indicating reduced interaction between airflow and the nasal mucosa in this region.

   - This contrasts with both aggressive ITR patients without ENS and healthy controls, who had more evenly distributed shear stress.

3. **Mucosal Sensory Function**:

   - ENS patients showed significantly impaired trigeminal sensory function, as indicated by lower menthol LDTs, compared to both aggressive ITR patients without symptoms and healthy controls.

   - Interestingly, aggressive ITR patients without ENS had slightly better sensory function compared to healthy controls, a surprising finding that may warrant further investigation.

#### **Conclusions**

- **Link Between Turbinate Reduction and ENS**: The study supports that aggressive ITR can alter nasal airflow patterns and mucosal function, which may contribute to ENS development. However, ENS symptoms are not solely attributable to the degree of turbinate reduction as similar degrees of turbinate reduction were observed in both ENS patients and those without symptoms.

- **Nasal Aerodynamics and Sensory Function**: The combination of distorted nasal aerodynamics and impaired mucosal sensory function appears to play a significant role in the development of ENS symptoms. ENS patients showed an abnormal distribution of airflow and reduced sensory feedback, which may contribute to their symptoms.

- **Implications for Surgery**: The findings suggest that while aggressive ITR can alter nasal airflow, careful consideration of how these changes impact mucosal function is crucial in preventing ENS. Balancing airflow distribution and preserving sensory function could be key in improving surgical outcomes and avoiding ENS.

#### **Key Learnings**

- **Airflow Dynamics**: Disrupted airflow patterns in ENS patients indicate that the condition may arise from more complex interactions between nasal anatomy and airflow, rather than just the extent of turbinate reduction.

- **Sensory Function**: Sensory impairment in ENS patients highlights the importance of maintaining nasal mucosal function during surgery.

- **Further Research**: More research is needed to refine surgical techniques and preventive strategies to mitigate ENS risk, potentially involving a more nuanced approach to turbinate reduction and sensory preservation.

This study provides valuable insights into the mechanisms underlying ENS and emphasizes the need for a balanced approach to turbinate reduction in nasal surgeries.