Evidence of Nasal Cooling and Sensory Impairments Driving Patient Symptoms With Septal Deviation

Effects of Mucosal Decongestion on Nasal Aerodynamics: A Pilot Study

OBJECTIVE

Mucosal decongestion with nasal sprays is a common treatment for nasal airway obstruction. However, the impact of mucosal decongestion on nasal aerodynamics and the physiological mechanism of nasal airflow sensation are incompletely understood. The objective of this study is to compare nasal airflow patterns in nasal airway obstruction (NAO) patients with and without mucosal decongestion and nondecongested healthy subjects.

STUDY DESIGN

Cross-sectional study of a convenience sample.

SETTING

Academic tertiary medical center.

METHODS

Forty-five subjects were studied (15 nondecongested healthy subjects, 15 nondecongested NAO patients, and 15 decongested NAO patients). Three-dimensional models of the nasal anatomy were created from computed tomography scans. Steady-state simulations of airflow and heat transfer were conducted at 15 L/min inhalation rate using computational fluid dynamics.

RESULTS

In the narrow side of the nose, unilateral nasal resistance was similar in decongested NAO patients and nondecongested healthy subjects, but substantially higher in nondecongested NAO patients. The vertical airflow distribution within the nasal cavity (inferior vs middle vs superior) was also similar in decongested NAO patients and nondecongested healthy subjects, but nondecongested NAO patients had substantially less middle airflow. Mucosal cooling, quantified by the surface area where heat flux exceeds 50 W/m2, was significantly higher in decongested NAO patients than in nondecongested NAO patients.

CONCLUSION

This pilot study suggests that mucosal decongestion improves objective measures of nasal airflow, which is consistent with improved subjective sensation of nasal patency after decongestion.

An adjoint-based approach for the surgical correction of nasal septal deviations

Deviations of the septal wall are widespread anatomic anomalies of the human nose; they vary significantly in shape and location, and often cause the obstruction of the nasal airways. When severe, septal deviations need to be surgically corrected by ear-nose-throat (ENT) specialists. Septoplasty, however, has a low success rate, owing to the lack of suitable standardized clinical tools for assessing type and severity of obstructions, and for surgery planning. Moreover, the restoration of a perfectly straight septal wall is often impossible and possibly unnecessary. This paper introduces a procedure, based on advanced patient-specific Computational Fluid Dynamics (CFD) simulations, to support ENT surgeons in septoplasty planning. The method hinges upon the theory of adjoint-based optimization, and minimizes a cost function that indirectly accounts for viscous losses. A sensitivity map is computed on the mucosal wall to provide the surgeon with a simple quantification of how much tissue removal at each location would contribute to easing the obstruction. The optimization procedure is applied to three representative nasal anatomies, reconstructed from CT scans of patients affected by complex septal deviations. The computed sensitivity consistently identifies all the anomalies correctly. Virtual surgery, i.e. morphing of the anatomies according to the computed sensitivity, confirms that the characteristics of the nasal airflow improve significantly after small anatomy changes derived from adjoint-based optimization.

Computational Fluid Dynamics and Its Potential Applications for the ENT Clinician

This article is an examination of computational fluid dynamics in the field of otolaryngology, specifically rhinology. The historical development and subsequent application of computational fluid dynamics continues to enhance our understanding of various sinonasal conditions and surgical planning in the field today. This article aims to provide a description of computational fluid dynamics, the methods for its application, and the clinical relevance of its results. Consideration of recent research and data in computational fluid dynamics demonstrates its use in nonhistological disease pathology exploration, accompanied by a large potential for surgical guidance applications. Additionally, this article defines in lay terms the variables analyzed in the computational fluid dynamic process, including velocity, wall shear stress, area, resistance, and heat flux.

How Does Oxymetazoline Change Nasal Aerodynamics and Symptomatology in Patients with Turbinate Hypertrophy?

OBJECTIVES

Oxymetazoline relieves nasal obstructive symptoms via vasoconstriction, however, the changes in nasal structures and aerodynamics that impact symptoms the most remain unclear.

METHODS

This prospective, longitudinal, and single blinded cohort study applied Computational Fluid Dynamic (CFD) modeling based on CT scans at baseline and post-oxymetazoline on 13 consecutive patients with chronic nasal obstruction secondary to inferior turbinate hypertrophy from a tertiary medical center. To account for placebo effect, a sham saline spray was administered with subject blindfolded prior to oxymetazoline, with 30 min rest in between. Nasal Obstruction Symptom Evaluation (NOSE) and unilateral Visual Analogue Scale (VAS) scores of nasal obstructions were collected at baseline, after sham, and 30 min after oxymetazoline.

RESULTS

Both VAS and NOSE scores significantly improved from baseline to post-oxymetazoline (NOSE: 62.3 ± 12.4 to 31.5 ± 22.5, p < 0.01; VAS: 5.27 ± 2.63 to 3.85 ± 2.59, p < 0.05), but not significantly from baseline to post-sham. The anatomical effects of oxymetazoline were observed broadly throughout the entire length of the inferior and middle turbinates (p < 0.05). Among many variables that changed significantly post-oxymetazoline, only decreased nasal resistance (spearman r = 0.4, p < 0.05), increased regional flow rates (r = -0.3 to -0.5, p < 0.05) and mucosal cooling heat flux (r = -0.42, p < 0.01) in the inferior but not middle turbinate regions, and nasal valve Wall Shear Stress (WSS r = -0.43, p < 0.05) strongly correlated with symptom improvement.

CONCLUSION

Oxymetazoline broadly affects the inferior and middle turbinates, however, symptomatic improvement appears to be driven more by global nasal resistance and regional increases in airflow rate, mucosal cooling, and WSS, especially near the head of the inferior turbinate.

LEVEL OF EVIDENCE

3: Well-designed, prospective, single blinded cohort trial. Laryngoscope, 134:1100-1106, 2024.

Assessment of Intranasal Function of the Trigeminal Nerve in Daily Clinical Practice

BACKGROUND

The trigeminal nerve is a mixed cranial nerve responsible for the motor innervation of the masticatory muscles and the sensory innervation of the face, including the nasal cavities. Through its nasal innervation, we perceive sensations, such as cooling, tingling, and burning, while the trigeminal system mediates the perception of airflow. However, the intranasal trigeminal system has received little attention in the clinical evaluation of patients with nasal pathology.

SUMMARY

Testing methods that enable the clinical assessment of intranasal trigeminal function have recently been developed. This study aims to present the current clinical methods that can be utilised in everyday practice, as described in the literature. These methods include four assessment techniques: (1) the quick screening test of trigeminal sensitivity involves patients rating the intensity of ammonium vapour presented in a lipstick-like container. (2) The lateralisation test requires subjects to identify which nasal cavity is being stimulated by a trigeminal stimulus, such as eucalyptol or menthol, while the other side receives an odourless stimulus. (3) The trigeminal sticks test evaluates the trigeminal function similarly to the olfactory function using sticks filled with trigeminal stimulant liquids. (4) The automated CO2 stimulation device is used for measuring trigeminal pain thresholds, utilising intranasal CO2 stimuli to define the pain threshold.

KEY MESSAGES

Assessing intranasal trigeminal function clinically may prove useful in evaluating rhinology patients, particularly those who encounter nasal obstruction without anatomical blockage and those experiencing olfactory disorders with suspected trigeminal dysfunction. Despite their limitations, the presented methods may provide useful information about nasal patency, chemosensitivity, and pain sensation in the daily clinical practice of such patients, leading to better therapeutic decisions.

Intranasal trigeminal sensitivity to mechanical stimuli is associated with the perception of nasal patency

PURPOSE

The aim of this prospective study was to examine the characteristics of a clinical test for the assessment of nasal trigeminal sensitivity to mechanical stimuli and its association with the perception of nasal patency.

METHODS

Thirty-two normosmic healthy subjects participated (17 women and 15 men; age = 26 ± 3 years). Precisely defined air puffs were used with a flow rate of 2L/min for mechanical stimulation. They were presented to the nasal vestibule, nasal septum, and inferior turbinate with various stimulus durations. Thresholds were measured by single-staircase stimuli with changes in stimulus duration in steps of 10 ms. Trigeminal suprathreshold intensity was rated by subjects for stimulus durations of 200, 300, 400, and 500 ms. Test-retest reliability was examined by intraclass correlations (ICCs) and Bland-Altman plot with limits of agreement. Pearson's correlations were calculated between self-rated nasal patency and nasal trigeminal sensitivity.

RESULTS

As indicated by trigeminal threshold and suprathreshold intensities, the nasal vestibule is the most sensitive area among the three locations, followed by the nasal septum and the inferior turbinate (p < 0.001). Coefficients of correlations between test and retest were 0.76 for thresholds, and 0.56 suprathreshold intensities (p < 0.001). The Bland-Altman analysis showed a good agreement between test-retest values. In addition, significant positive associations between trigeminal suprathreshold intensities and self-rated nasal obstruction were found at the inferior turbinate (r = 0.4, p < 0.05).

CONCLUSION

Reliable assessment of nasal trigeminal sensitivity for air puffs appears to be possible. Nasal trigeminal suprathreshold sensitivity to mechanical stimuli is associated with the perception of nasal patency at the inferior turbinate. This opens a window into the assessment of the perception of nasal airflow in various clinical purposes, especially for patients with sinonasal diseases.

LEVEL OF EVIDENCE: 3

Impact of the Location of Nasal Septal Deviation on the Nasal Airflow and Air Conditioning Characteristics

The location of nasal septal deviation (NSD) directly impacts nasal physiology. The objective is to examine, using computational fluid dynamics (CFD), the difference in the airflow and air conditioning characteristics according to the location of NSD. Twenty patients with septal deviation were divided into two: 10 caudal septal deviation (CSD) and 10 posterior septal deviation (PSD). Physiological variables were compared and numerical models for nasal cavity were created with CT scans. Cases with CSD had distinctive features including restricted airflow partition, larger nasal resistance, and decreased surface heat flux in the more obstructed side (MOS), and lower humidity and air temperature in the lesser obstructed side (LOS). Physiological differences were observed according to the location of septal deviation, CSD cases exhibit significantly more asymmetric airflow characteristics and air conditioning capacity between LOS and MOS.

A comparison of men and women undergoing septoplasty-the Swedish national septoplasty register

Objective

Men represent more than two-thirds of septoplasty patients in many studies, but differences between men and women in terms of patient selection or outcome are seldom reported. This study aims to investigate whether women undergoing septoplasty differ from men in critical variables before and after surgery, in a large national sample of septoplasties.

Design

Cross-sectional register study.

Participants

The study includes 2,532 patients from the National Swedish Septoplasty Register undergoing septoplasty with or without additional turbinoplasty on the indication of nasal obstruction in 2014-2019. Patients in the register have not been preselected.

Main outcome measures

Preoperative variables and postoperative outcome were compared between men and women.

Results

Men accounted for 1,829 (72%) of the patients. There was no significant difference between men and women in severity of self-reported nasal obstruction or type of surgery performed (septoplasty with or without turbinoplasty). Mean postoperative nasal obstruction 12 months after surgery and overall satisfaction with the result were similar. Women, however, reported more complications 12 months postoperatively, while men reported more problems with snoring and obstructive sleep apnea preoperatively.

Conclusion

In this large national patient cohort undergoing septoplasty, we found no differences in preoperative nasal obstruction or postoperative patient-rated outcome in men and women undergoing septoplasty, despite the fact that 72% of the patients were men. It thus remains unclear why women are under-represented in septoplasty surgery in this and many other cohorts.

Otolaryngologists' radiological assessment of nasal septum deviation symptomatology

OBJECTIVES

Nasal Septal Deviation (NSD) is one of the most common causes of nasal obstruction. This study aims to further examine the clinical utility of imaging assessment in the workup and management of symptomatic nasal septal deviation, across all levels of medical training.

STUDY DESIGN

Cross-sectional survey.

METHODS

CT scans of 10 confirmed NSD patients and 36 healthy controls (HC) were mixed and emailed through anonymous REDCap surveys to otolaryngologists in the US. The HC had no reported sinonasal obstruction symptoms-NOSE (NSD: 62.2 ± 12.5; HC: 5.69 ± 5.99, p < 0.05); SNOT-22 (NSD: 31.4 ± 14.5; HC: 9.72 ± 10.76, p < 0.05). The images consisted of a coronal slice at each subject's most deviated location. Participants were instructed to choose the patients suspected to present with symptoms of sinonasal obstruction.

RESULTS

88 otolaryngologists responded to the survey. 18 were excluded due to incomplete responses. On average, they identified 64.2 ± 29.8% of symptomatic NSD subjects correctly, but misidentified 54.6 ± 34.6% of HC as symptomatic. Their decisions were strongly correlated to degree of NSD (r = 0.69, p < 0.05). There exists a significant degree of NSD among HC (38.7 ± 17.2%), which does not significantly differ from symptomatic subjects (51.0 + 18.7%, p = 0.09). Residents and fellows performed similarly, with responses correlated between levels of training (r = 0.84-0.96, p < 0.05).

CONCLUSIONS

The incorporation of a substantial number of otolaryngologists, large patient sample, and blind mixing with HC gives us greater insight to the relative contribution of the extent of septal deviation to symptoms of nasal obstruction. Although NSD is a common factor contributing to nasal obstruction, the results of this study suggest that it is difficult to reliably infer obstructive symptoms based on degree of NSD on CT.

LEVEL OF EVIDENCE

Three.

Unmet challenges in septoplasty–nordic studies from a uniform healthcare and geographical area

Purpose

Nasal septoplasty is one of the most common surgical procedures in otorhinolaryngology and optimising both patient selection and the surgery is a challenge. The Nordic countries have similar public healthcare systems and comparable populations in terms of size.

Methods

This is a review of studies of outcome and predictors related to septoplasty from Denmark, Finland, Norway and Sweden, published during the last decade. The aim of this review was to identify areas in need of further research to meet the challenges of septoplasty in the Nordic countries with reference to international data.

Results

Postoperative patient satisfaction at 6–12 months was reported in around 2/3 of the patients and well in line with international data. Patients with more severe symptoms had a higher chance of improvement. Lack of standardisation in patient selection, surgical methods and skills, and follow up procedures, still makes it difficult to explain the 25% failure rate in septoplasty surgery.

Conclusion

This review of the Nordic studies from the last decade shows that septoplasty in general is effective in relieving nasal obstruction. There is a need for studies addressing the standardisation of diagnostic tools and algorithms and the systematic and continuous implementation of follow-up of the surgical results at both departmental and personal level. This includes an awareness of how surgical skills in septoplasty are obtained and maintained.

Comparison of rhinomanometric and computational fluid dynamic assessment of nasal resistance with respect to measurement accuracy

PURPOSE

Computational fluid dynamics (CFD)-based calculation of intranasal airflow became an important method in rhinologic research. Current evidence shows weak to moderate correlation as well as a systematic underprediction of nasal resistance by numerical simulations. In this study, we investigate whether these differences can be explained by measurement uncertainties caused by rhinomanometric devices and procedures. Furthermore, preliminary findings regarding the impact of tissue movements are reported.

METHODS

A retrospective sample of 17 patients, who reported impaired nasal breathing and for which rhinomanometric (RMM) measurements using two different devices as well as computed tomography scans were available, was investigated in this study. Three patients also exhibited a marked collapse of the nasal valve. Agreement between both rhinomanometric measurements as well as between rhinomanometry and CFD-based calculations was assessed using linear correlation and Bland-Altman analyses. These analyses were performed for the volume flow rates measured at trans-nasal pressure differences of 75 and 150 Pa during inspiration and expiration.

RESULTS

The correlation between volume flow rates measured using both RMM devices was good (R² > 0.72 for all breathing states), and no relevant differences in measured flow rates was observed (21.6 ml/s and 14.8 ml/s for 75 and 150 Pa, respectively). In contrast, correlation between RMM and CFD was poor (R² < 0.5) and CFD systematically overpredicted RMM-based flow rate measurements (231.8 ml/s and 328.3 ml/s). No differences between patients with and without nasal valve collapse nor between inspiration and expiration were observed.

CONCLUSION

Biases introduced during RMM measurements, by either the chosen device, the operator or other aspects as for example the nasal cycle, are not strong enough to explain the gross differences commonly reported between RMM- and CFD-based measurement of nasal resistance. Additionally, tissue movement during breathing is most likely also no sufficient explanation for these differences.

[Correlation between nasal mucosal temperature change and nasal airflow perception]

The mechanism of nasal airflow perception remains little known. It is currently believed that the main mechanism for perceiving nasal patency is to activate transient receptor potential melastatin subtype 8. Computer fluent dynamics show that increased airflow and heat flux are associated with higher subjective scores. Similarly, physical measurements of the nasal cavity using a temperature probe show a correlation between the lower nasal mucosa temperature and better results. Trigeminal function detection also indirectly confirms this. This literature review aimed to explore the role of nasal mucosal temperature change in the subjective perception of nasal patency and the secondary aim was to appraise the relevant evidence about the mechanism.

Piezo-assisted Turbinoplasty Versus Partial Turbinectomy in External Septorhinoplasty: A Prospective Comparative Study in 100 Patients

OBJECTIVES

The purpose of this study was to compare the outcome of the piezo-assisted turbinoplasty with a partial turbinectomy technique in the treatment of chronic nasal obstruction due to inferior turbinate enlargement.

STUDY DESIGN

This is a prospective randomized single-center study in a cohort of 100 consecutive patients which underwent external septorhinoplasty and concomitant hybrid type of turbinoplasty.

METHODOLOGY

Patients were randomly assigned into two groups. The first group included 50 patients who underwent piezo-assisted outfracturing of the inferior turbinates in combination with bipolar coagulation. The second group included 50 patients who underwent a treatment based on turbinate bipolar coagulation and partial resection of the inferior border of the turbinate. The severity of nasal obstruction was measured in both patient groups with a patient-related outcome questionnaire (NOSE) and objective measures (anterior rhinomanometry and acoustic rhinometry). Assessments were conducted prior to surgery and 3 months after the surgery.

RESULTS

There was a significant improvement in the values of the NOSE questionnaire with no relevant difference between the two study groups. Acoustic rhinometry and rhinomanometry also showed no statistically significant differences between the two study groups. No differences in postoperative healing were found, and postoperative complications were comparable low in both groups. However, the piezo-assisted procedure was quicker to perform with only minimal bleeding.

CONCLUSION

During septorhinoplasty, the combination of thermo-coagulation with piezo-assisted turbinoplasty was as efficient as with partial turbinectomy to establish normal nasal breathing.

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 www.springer.com/00266 .