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.

Temperature Profile Measurement From Radiofrequency Nasal Airway Reshaping Device

OBJECTIVE

Nasal airway obstruction (NAO) is caused by various disorders including nasal valve collapse (NVC). A bipolar radiofrequency (RF) device (VivAer®, Aerin Medical, Sunnyvale, CA) has been used to treat NAO through RF heat generation to the upper lateral cartilage (ULC). The purpose of this study is to measure temperature elevations in nasal tissue, using infrared (IR) radiometry to map the spatial and temporal evolution of temperature.

STUDY DESIGN

Experimental and computational.

METHODS

Composite porcine nasal septum was harvested and sectioned (1 mm and 2 mm). The device was used to heat the cartilage in composite porcine septum. An IR camera (FLIR® ExaminIR, Teledyne, Wilsonville, OR) was used to image temperature on the back surface of the specimen. These data were incorporated into a heat transfer finite element model that also calculated tissue damage using Arrhenius rate process.

RESULTS

IR temperature imaging showed peak back surface temperatures of 49.57°C and 42.21°C in 1 and 2 mm thick septums respectively. Temperature maps were generated demonstrating the temporal and spatial evolution of temperature. A finite element model generated temperature profiles with respect to time and depth. Rate process models using Arrhenius coefficients showed 30% chondrocyte death at 1 mm depth after 18 s of RF treatment.

CONCLUSION

The use of this device creates a thermal profile that may result in thermal injury to cartilage. Computational modeling suggests chondrocyte death extending as deep as 1.4 mm below the treatment surface. Further studies should be performed to improve dosimetry and optimize the heating process to reduce potential injury. Laryngoscope, 134:1063-1070, 2024.

Estimation of Nasal Airway Cross-sectional Area From Endoscopy Using Depth Maps: A Proof-of-Concept Study

OBJECTIVE

Endoscopy is routinely used to diagnose obstructive airway diseases. Currently, endoscopy is only a visualization technique and does not allow quantification of airspace cross-sectional areas (CSAs). This pilot study tested the hypothesis that CSAs can be accurately estimated from depth maps created from virtual endoscopy videos.

STUDY DESIGN

Cross-sectional.

SETTING

Academic tertiary medical center.

METHODS

Virtual endoscopy and depth map videos of the nasal cavity were digitally created based on anatomically accurate three-dimensional (3D) models built from computed tomography scans of 30 subjects. A software tool was developed to outline the airway perimeter and estimate the airspace CSA from the depth maps. Two otolaryngologists used the software tool to estimate the nasopharynx CSA and the nasal valve minimal CSA (mCSA) in the left and right nasal cavities. Model validation statistics were performed.

RESULTS

Nasopharynx CSA had a median percent error of 3.7% to 4.6% when compared to the true values measured in the 3D models. Nasal valve mCSA had a median percent error of 22.7% to 33.6% relative to the true values. Raters successfully used the software tool to identify subjects with nasal valve stenosis (ie, mCSA < 0.20 cm2 ) with a sensitivity of 83.3%, specificity ≥ 90.7%, and classification accuracy ≥ 90.0%. Interrater and intrarater agreements were high.

CONCLUSION

This study demonstrates that airway CSAs in 3D models can be accurately estimated from depth maps. The development of artificial intelligence algorithms to compute depth maps may soon allow the quantification of airspace CSAs from clinical endoscopies.

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.

The Role of Nasal Endoscopy in the Preoperative Evaluation of Nasal Airway Obstruction

OBJECTIVE

To examine the prevalence and nature of nasal endoscopic findings in patients referred for structural nasal obstruction, and analyze how such findings influence the preoperative evaluation or operative plan.

STUDY DESIGN

Cross-sectional study.

SETTING

University-based academic otolaryngology practice.

METHODS

Nasal endoscopy was performed by a single surgeon and the exam findings were documented. Patient demographics, variables in the patient history, Nasal Obstruction Symptom Evaluation scores, and an Ease-of-Breathing Likert Scale were tested for associations with findings on endoscopy.

RESULTS

A total of 82 of 346 patients (23.7%) had findings on rigid nasal endoscopy not appreciable on anterior rhinoscopy. Prior nasal surgery (p = .001) and positive allergy testing (p = .013) were significantly associated with findings on nasal endoscopy. Endoscopic findings prompted additional preoperative studies in 50 (14.5%) patients, and a change in the operative plan in 26 (7.5%) patients.

CONCLUSION

In patients referred for surgical management of nasal obstruction, findings on nasal endoscopy otherwise undetected with anterior rhinoscopy are most common in but certainly not limited to those with prior nasal surgery or allergic rhinitis. Routine nasal endoscopy should be considered for all patients being evaluated for nasal airway surgery. These results may benefit future updates of the clinical consensus statements regarding the role of nasal endoscopy in the evaluation of nasal valve compromise and septoplasty.

Value of Opening the Middle Meatus in Patients With Nasal Airway Obstruction

OBJECTIVES

While surgeries to correct the anatomical malformations that cause nasal airway obstruction (NAO) are generally successful, the outcomes of such procedures are often unsatisfactory. The aim of the present study was to assess the value of opening the middle meatus in patients with NAO.

METHODS

Thirty-four patients with nasal obstruction due to nasal septal deviation were included in this study. After randomization, the middle meatus was either opened or not opened during septoplasty. The patients were evaluated through pre- and postoperative rhinomanometry and acoustic rhinometry. The Visual Analog Scale (VAS) scores of subjective symptoms along with responses to the 20-item Sinonasal Outcome Test (SNOT-20) were obtained before surgery and three months after surgery.

RESULTS

The VAS scores and SNOT-20 responses improved significantly in both groups after surgery. The effective treatment rate based on the nasal congestion score (NCS) was 64.7% in the single group (septoplasty alone) and 100% in the combined group (septoplasty in conjunction with opening the middle meatus), and the difference was statistically significant (P = .018). In both groups, surgery significantly improved nasal flow, resistance, minimal cross-sectional area, cross-sectional area 6 cm (CA6) from the anterior nostril and nasal volume. Nasal volume and CA6 after surgery were statistically different between the 2 groups (P = .004 and .019, respectively).

CONCLUSIONS

Opening the middle meatus may further improve the subjective perception of patency on the basis of septoplasty.

Prevalence and Identification of Nasal Airway Obstruction in Patients Presenting to Otolaryngology Clinics: Results From a Large Descriptive Practice Survey

Objective: Determine the prevalence of nasal airway obstruction (NAO) in patients presenting to general otolaryngology clinics using the Nasal Obstruction Symptom Evaluation Scale (NOSE) score as a screening tool. Study Design: The clinic staff at 149 otolaryngology specialty clinics geographically distributed in the United States administered the NOSE Scale assessment to 3533 patients presenting to the clinics over a period of 1 week, regardless of the reason for the visit. All patients completed the NOSE Scale score, and additional data were collected, including the primary reason for the visit. Demographic and patient characteristics were summarized using frequencies and percentages for categorical variables. Results: The overall mean NOSE Scale score for the 3533 patients surveyed was 37.6 (SD 31.5). A total of 37.4% (1320/3533) of surveyed patients, regardless of visit reason, had severe/extreme NAO symptoms. Overall, the most common visit reason category was "Other" (61.2%, 2162/3533), followed by "NAO" (22.6%, 798/3533) and "Sinus" (16.2%, 573/3533). The mean NOSE scores for patients in each of the visit categories were 23.4 (SD 25.9), 64.7 (SD 23.3), and 53.3 (SD 28.1); for "Other," "NAO," and "Sinus," respectively. Among the patients coming in with "NAO" or "Sinus" as a primary complaint, 76.2% (608/798) and 57.2.% (328/573) had severe or extreme NOSE scores. A total of 17.8% (384/2162) of patients coming in for "Other" reasons had NOSE scores indicating severe/extreme NAO symptoms. Conclusions: The findings of this large, descriptive otolaryngology practice survey found a high prevalence of moderate to severe/extreme NAO among patients presenting to otolaryngology practices. Incorporating assessments, such as the NOSE Scale score and other diagnostic practices into the patient intake workflow and assessments, could help identify symptomatic NAO patients that might otherwise be overlooked.

Two-year outcomes of temperature-controlled radiofrequency device treatment of the nasal valve for patients with nasal airway obstruction

Background

The objective of this study was to evaluate long-term symptom improvements in patients with nasal airway obstruction (NAO) secondary to nasal valve collapse (NVC) following minimally invasive temperature-controlled radiofrequency (TCRF) treatment.

Methods

A prospective, single-arm, multicenter study in patients >18 years with NAO due to NVC. Inclusion criteria were response to nasal valve dilation (e.g., modified Cottle maneuver) and baseline Nasal Obstruction Symptom Evaluation (NOSE) Scale score ≥60. Patients were treated in the nasal valve region with a TCRF device and followed through 2 years. A responder was ≥20% reduction NOSE Scale score or ≥1 reduction in severity class.

Results

A total of 122 patients were treated and 91 reached 2 years. The mean baseline NOSE Scale score was 80.3 (95% CI, 78.1-82.6). The adjusted mean change in score at 2 years was -45.8 (95% CI, -53.5 to -38.1), p < 0.001; a 57.0% improvement. The 2-year responder rate was 90.1% (95% CI, 82.3%-94.7%). Significant and sustained symptom improvement was achieved in subpopulations based on sex, age, body mass index, baseline NAO severity, nasal surgery history, NVC mechanism, septal deviation, and other anatomic contributors of NAO. No serious adverse events with a relationship to the study device and/or procedure were reported.

Conclusions

Minimally invasive TCRF device treatment of the internal nasal valve for NAO is well tolerated and leads to significant and sustained improvement in NAO symptom severity through 2 years, including in patients with both static and dynamic NVC, septal deviation, turbinate enlargement, or prior nasal surgery.

Level of Evidence

2b.

Adverse Events Associated With Bioabsorbable Nasal Implants: A MAUDE Database Analysis

Bioabsorbable implants (eg, Latera) have recently been approved for addressing nasal valve collapse. The purpose of this study is to summarize adverse events and treatment sequelae associated with bioabsorbable nasal implants queried in the Manufacturer and User Facility Device Experience (MAUDE) database. Of the 26 device reports entered between March 2017 and April 2022, the most frequently reported complications included abscess (n = 13) and implant protrusion (n = 5). Other common symptoms reported greater than 1-year postimplantation included facial pain/discomfort (n = 3) and failure to absorb (n = 3). Management of adverse events included treatment with antibiotics (n = 9), steroid injections (n = 4), and explantation (n = 20). In 3 reports, adverse reactions required a biopsy of adjacent tissue for pathologic analysis. These findings suggest that further research is required to assess the potential long-term complications and optimize the management of bioabsorbable nasal implants. Furthermore, standardized reporting templates may improve the utility of the MAUDE database.

Nasal airway obstruction and orofacial pain: a multicenter retrospective analysis

The aim of this study was to investigate the relationship between nasal airway obstruction (NAO) and symptoms of orofacial pain, including temporomandibular joint pathology and primary headaches. This study was a retrospective analysis of consecutive patients seeking care for chronic orofacial pain at 14 North American treatment centers. The standardized evaluation protocol followed for all patients included cone beam computed tomography (CBCT), a comprehensive clinical examination, and a thorough review of the patient's subjective complaints and health history, including pain and sleep pathology. The primary conditions of interest in this study were the following 5 types of NAO: nasal valve compromise (NVC), deviated septum, septal swell body, concha bullosa, and inferior turbinate soft tissue hypertrophy. Descriptive statistics and regression analysis were performed to determine comorbidities between orofacial pain symptoms and NAO observed on CBCT images. The study population consisted of 1393 patients, 253 men (18.2%) and 1140 women (81.8%). The mean age of the patients was 43.3 (SD 18.1) years. NVC was the most prevalent type of NAO found in the study population (n = 1006; 72.2%). NVC showed a statistically significant comorbidity with capsulitis (odds ratio, 3.73) as well as facial and cervical myositis (odds ratio, 6.97). To the author's knowledge, this is first time that these comorbidities have been identified. NAO had a high comorbidity with orofacial pain. Specifically, NVC was a major contributor to NAO. An understanding of the mechanisms of orofacial pain as well as the effects of improper (mouth) breathing, adaptive forward head posture, muscular fatigue, parafunction, and temporomandibular joint pathology will help the clinician to evaluate the role a patient's nose may be playing in orofacial pain.

Is there a relationship of nasal septum deviation with pharyngeal airway dimension and craniocervical posture?

OBJECTIVE

This study aimed to evaluate the effects of nasal septum deviation on the pharyngeal airway and craniocervical posture measurements using cone beam computed tomography (CBCT).

METHODS

This retrospective study analyzed the CBCTs of 25 patients with and without nasal septum deviation. Various parameters defining the pharyngeal airway and craniocervical and facial skeletal morphology were measured and compared between the groups after confirming intra-examiner reliability.

RESULTS

Compared to the control group, the group with nasal septum deviation had a statistically significantly shorter nasopharyngeal length (p < 0.001), longer vertical airway length (p < 0.002), and larger cervical column curvature angle (p < 0.006).

CONCLUSION

Children with a nasal septum deviation of 4 mm or more on their CBCT scan are susceptible to unfavorable pharyngeal airway and craniocervical postural changes.

Novel 3D segmentation for reliable volumetric assessment of the nasal airway: a CBCT study

OBJECTIVE

Nasal airway obstruction affects up to one-third of Americans and is one of the most common complaints by patients to otolaryngologists. Nasal airway obstruction and obstructive sleep apnea syndrome (OSAS) are closely related. The aim of this study was to use the 3D imaging software, ITK-SNAP as a platform to define a gold standard for anatomically accurate boundaries of the nasal airway in 3D CBCT and to create a more reliable and precise 3D CBCT segmentation of the nasal airway for assisting diagnosis, treatment, and monitoring of nasal airway obstruction and OSAS.

METHOD AND MATERIALS

After review of the literature to identify established parameters using CBCT and CT technology for the segmentation of the nasal airway, and the existing drawbacks, a gold standard for locating the anatomical boundaries of the nasal airway using CBCT is proposed. This new method aims at standardization of segmentation and quantification, allowing for more reliable comparison between studies. ITK-SNAP software was used to segment three CBCT samples of healthy patients aged 21 to 59 years, who were patients of record, with CBCT obtained for either orthodontic, endodontic, or prosthodontic treatment planning purposes. <br />Results: The literature search identified 11 studies describing nasal airway parameters utilizing CBCT and CT. A great variation was detected on where the anatomical boundaries for the nasal airway were selected. A new standard in the identification of anatomical boundaries of the nasal airway is proposed for consistent segmentation and quantification using 3D CBCT by using the following landmarks: the inferior ANS-PNS border, the anterior nares border, the posterior sella-PNS border, and superiorly the border in alignment with the base of the skull (excluding the ostia, frontal, ethmoidal, and sphenoidal air cells). The three segmented samples were volumetrically measured, and statistically analyzed. The mean average Hounsfield unit intensity using the CBCT samples in this study was 629 with a standard deviation of 190. <br />Conclusion: The literature indicates a lack of a gold standard using CBCT technology for the segmentation of the nasal airway. With the proposed standard in this study, it is possible to quantify the nasal airway volume and thereby its reduction. For the general dental practitioner, this is an important aspect during the evaluation of overall airway assessment. This information can be useful in the diagnosis and treatment of airway compromised dental patients. (Quintessence Int 2021;52:154-164; doi: 10.3290/j.qi.a45429).

Comparison of nasal airway obstruction with sonoelastography and nose obstruction symptom evaluation scores in children with allergic rhinitis

Objective

Nasal airway obstruction caused by inferior turbinate hypertrophy is the most troublesome symptom for patients with allergic rhinitis. The aim of this study was to determine any correlation between different nasal obstruction measurements in children with allergic rhinitis.

Material and Methods

Nasal airway obstruction was assessed with Sonoelastography, Turkish version of the Nose Obstruction Symptom Evaluation scale, Rhinoconjunctivitis Total Symptom Score and visual analog scale methods in children with allergic rhinitis and the results were compared with a healthy control group.

Results

Evaluation was made of a total of 68 patients (40 boys and 28 girls [male: female ratio, 1.42]) with a mean age of 13.35±3.35 (range, 7-18) years. The Rhinoconjunctivitis Total Symptom Score, visual analog scale, and Turkish version of the Nose Obstruction Symptom Evaluation scale scores were significantly higher in the AR group than in the control group (p=0.001, p=0.001, p=0.001, respectively). The sonoelastography scores were significantly higher in the AR group than in the control group (p=0.001). Although a positive significant correlation was determined between Rhinoconjunctivitis Total Symptom Score, visual analog scale, and Turkish version of the Nose Obstruction Symptom Evaluation scale scores in terms of AR severity, no relationship was found with the sonoelastography scores (p=0.022, p=0.009, p=0.001, and p=0.0751, respectively).

Conclusion

The Turkish version of the Nose Obstruction Symptom Evaluation scale and sonoelastography can be used to evaluate nasal obstruction due to inferior turbinate hypertrophy in children with allergic rhinitis.

Rhinomanometry Versus Computational Fluid Dynamics: Correlated, but Different Techniques

BACKGROUND

Past studies reported a low correlation between rhinomanometry and computational fluid dynamics (CFD), but the source of the discrepancy was unclear. Low correlation or lack of correlation has also been reported between subjective and objective measures of nasal patency.

OBJECTIVE

This study investigates (1) the correlation and agreement between nasal resistance derived from CFD (R_CFD) and rhinomanometry (R_RMN), and (2) the correlation between objective and subjective measures of nasal patency.

METHODS

Twenty-five patients with nasal obstruction underwent anterior rhinomanometry before and after mucosal decongestion with oxymetazoline. Subjective nasal patency was assessed with a 0-10 visual analog scale (VAS). CFD simulations were performed based on computed tomography scans obtained after mucosal decongestion. To validate the CFD methods, nasal resistance was measured in vitro (R_EXPERIMENT) by performing pressure-flow experiments in anatomically accurate plastic nasal replicas from 6 individuals.

RESULTS

Mucosal decongestion was associated with a reduction in bilateral nasal resistance (0.34 ± 0.23 Pa.s/ml to 0.19 ± 0.24 Pa.s/ml, p = 0.003) and improved sensation of nasal airflow (bilateral VAS decreased from 5.2 ± 1.9 to 2.6 ± 1.9, p < 0.001). A statistically significant correlation was found between VAS in the most obstructed cavity and unilateral airflow before and after mucosal decongestion (r = -0.42, p = 0.003). Excellent correlation was found between R_CFD and R_EXPERIMENT (r = 0.96, p < 0.001) with good agreement between the numerical and in vitro values (R_CFD/R_EXPERIMENT = 0.93 ± 0.08). A weak correlation was found between R_CFD and R_RMN (r = 0.41, p = 0.003) with CFD underpredicting nasal resistance derived from rhinomanometry (R_CFD/R_RMN = 0.65 ± 0.63). A stronger correlation was found when unilateral airflow at a pressure drop of 75 Pa was used to compare CFD with rhinomanometry (r = 0.76, p < 0.001).

CONCLUSION

CFD and rhinomanometry are moderately correlated, but CFD underpredicts nasal resistance measured in vivo due in part to the assumption of rigid nasal walls. Our results confirm previous reports that subjective nasal patency correlates better with unilateral than with bilateral measurements and in the context of an intervention.

Pulmonary arterial pressure and nasal obstruction in mouth-breathing children: Similarities between adenotonsillar hypertrophy and allergic rhinitis

BACKGROUND

Upper airway obstruction may cause pulmonary hypertension in childhood. In this study we aimed to identify a possible correlation of systolic pulmonary arterial pressure (SPAP), using Doppler echocardiography, with nasal patency (NP), as measured by rhinomanometry, in mouth-breathing (MB) children with allergic rhinitis (AR) and adenotonsillar hypertrophy (ATH).

METHODS

In this cross-sectional study we evaluated 183 patients, from 2 to 12 years of age, at an MB referral clinic in Brazil, from December 2013 to 2017. We allocated patients to 4 etiology groups: group 1, 60 MBs with ATH; group 2, 47 MBs with AR; group 3, 43 MBs with both ATH and AR; and group 4, 33 nasal breathing control subjects. The ratio of total nasal inspiratory flow (assessed by active anterior rhinomanometry) and expected inspiratory flow adjusted for height determined the percent NP (%NP).

RESULTS

The median %NP was higher in controls than in the MB groups (controls, 114% [79-147%]; ATH: 65% [5-116%]; AR: 57% [23-144%]; ATH and AR: 64% [3-120%]; p < 0.001). Median SPAP was higher in the MB groups than in controls (SPAP: ATH, 26.0 [20.0-35.0] mmHg; AR, 26.0 [22.0-32.0] mmHg; ATH and AR, 26.30 [20.0-34.0] mmHg; control, 22.0 [16.0-30.0] mmHg; p < 0.001). SPAP showed a negative association with %NP (Spearman's rho = -0.24; p < 0.001).

CONCLUSION

Reduced nasal airflow in MB children showed a correlation with higher levels of systolic pulmonary arterial pressure. The AR and ATH groups were similar in nasal obstruction severity and systolic pulmonary arterial pressure level distribution.

Side asymmetry in nasal resistance correlate with nasal obstruction severity in patients with septal deformities: Computational fluid dynamics study

OBJECTIVES

The objective of this study was to investigate the relationship between side asymmetry in nasal resistance (NR) and severity of the nasal airway obstruction (NAO) in patients with different types of nasal septal deformity (NSD).

DESIGN

Computational fluid dynamics (CFD) study.

SETTING

The study was conducted in a tertiary medical centre.

PARTICIPANTS

The study included 232 patients, who were referred to the CT examination of the paranasal sinuses. Exclusion criteria were sinonasal and respiratory diseases that may interfere with the nasal obstruction. The presence and the type of NSD were recorded according to the Mladina's classification.

MAIN OUTCOME MEASURES

The presence and severity of NAO in each patient were assessed by NOSE questionnaire. Eight computational models of the nasal cavity were created from CT scans. Models represented seven Mladina's NSD types and a straight septum of a symptomless patient. CFD calculated airflow partitioning and NR for each nasal passage. Side differences in NR were calculated by the equation ∆NR = NR_left  - NR_right . The relationship between NOSE scores, airflow partitioning and side differences in NR was explored using Spearman's correlation analysis.

RESULTS

Mladina's types of NSD showed differences in airflow partitioning and the degree of side asymmetry in NR. A significant positive correlation was detected between side differences in NR and NOSE scores (R = .762, P = .028). A significant negative correlation was found between the per cent of unilateral airflow and NR (R = -.524, P = .037).

CONCLUSIONS

Our results demonstrated that side asymmetry in NR could explain differences in NAO severity related to the NSD type.

Correlations between computational fluid dynamics and clinical evaluation of nasal airway obstruction due to septal deviation: An observational study

OBJECTIVES

The primary objective of this study was to determine how computational fluid dynamics (CFD) could be correlated to clinical evaluation of nasal airway obstruction (NAO) in a population of patients with symptomatic septal deviation (SD). The secondary objective was to determine whether CFD could define which side was the more obstructed.

DESIGN

This was an observational study.

SETTINGS

Few publications have attempted to correlate CFD with clinical evaluation of NAO. This correlation would permit validation and improved interpretation. This study was performed in a university research laboratory specialised in fluid mechanics.

PARTICIPANTS

We included patients referred for septal surgery at our centre. Age range was 19-58 years. Preoperative CT scans were performed. All patients with non-structural causes of NAO such as rhinitis, sinusitis or tumoral/autoimmune processes (ie, not due to anatomic obstruction) were excluded.

MAIN OUTCOME MEASUREMENT

For each nasal fossa, we compared CFD data (total pressure, heat flux, wall shear stress, temperatures, velocity and nasal resistances) with both patient perception scores and rhinomanometry using the Spearman correlation test (r_s ). Perception scores were graded from 0/4 to 4/4 on each side, based on the patient interview. We also compared CFD-derived nasal resistances with rhinomanometry-derived nasal resistances.

RESULTS

Twenty-two patients complaining of NAO with SD were analysed, and 44 analyses were performed comparing each side with its CFD data. Regarding correlations with patient perception scores, the best values we found were heat flux measures (r_s  = 0.86). Both rhinomanometry and CFD-calculated nasal resistances had strong correlations with subjective perception scores (r_s  = 0.75, P < 0.001 and r_s  = 0.6, P < 0.001, respectively). We found a statistically significant difference between RMM-NR and CFD-NR (P = 0.003). Heat flux analysis allowed us to distinguish the more obstructed side (MOS) and the less obstructed side (LOS) in 100% of patients.

CONCLUSION

This study aimed to enhance our ability to interpret CFD-calculated data in the nasal airway. It highlights and confirms that heat flux measures are very closely correlated to patient perception in cases of SD. It also helps to distinguish the more obstructed side from the less obstructed side and could contribute to further CFD studies.

Preoperative characteristics of over 1,300 functional septorhinoplasty patients

OBJECTIVE

To identify characteristics of patients presenting preoperatively for functional septorhinoplasty associated with increased Nasal Obstruction Symptom Evaluation (NOSE) scores.

STUDY DESIGN

Retrospective analysis of a prospective cohort at a tertiary medical center. Only baseline assessments were analyzed in this cross-sectional study.

METHODS

1,338 patients completed baseline nasal evaluation, resulting in 1,034 NOSE scores. Demographics, medical history, surgical history, and physical exam findings were recorded.

RESULTS

The average preoperative NOSE score was 59.8 out of 100 (standard deviation: 24.9). Fifty-four percent (578 per 1,074) of respondents were female, although sex did not affect baseline NOSE score (P = 0.7). Forty-five percent (404 per 896) reported prior nasal surgery. History of rhinoplasty was not associated with a difference in baseline NOSE score (P = 0.1924); however, history of septoplasty (P = 0.0390) was associated with an increased baseline NOSE score. Snoring was also both associated with higher baseline NOSE score (P = 0.0003). All 12 septal/nasal valve measurements were associated with higher preoperative NOSE score, whereas the internal nasal valve narrowing variables retained significance in multivariate analysis (left: P = .0490; right: P = .0077).

CONCLUSION

Patients presenting for nasal airway obstruction were evaluated. Sex was not associated with difference in NOSE score. History of septoplasty was associated with higher baseline NOSE score, as were snoring and internal nasal valve narrowing at rest.

LEVEL OF EVIDENCE

2C Laryngoscope, 130:25-31, 2020.

Effect of Nasal Valve Shape on Downstream Volume, Airflow, and Pressure Drop: Importance of the Nasal Valve Revisited

OBJECTIVES

The relative importance of the nasal valve relative to the remainder of the nasal airway remains unknown. The goal of this article was to objectively measure the shape of the nasal inlet and its effect on downstream airflow and nasal cavity volume using a physical model and a physiologic flow model.

METHODS

A patient who had isolated nasal valve surgery and had pre- and postoperative computed tomography scans available for analysis was studied. Nasal inlet shape measurements, computational fluid dynamics, and nasal volume analysis were performed using the computed tomography data. In addition, a physical model was used to determine the effect of nasal obstruction on downstream soft tissue.

RESULTS

The postoperative shape of the nasal inlet was improved in terms of length and degree of tortuosity. Whereas the operated-on region at the nasal inlet showed an only 25% increase in cross-sectional area postoperatively, downstream nonoperated sites in the nasal cavity revealed increases in area ranging from 33% to 51%. Computational fluid dynamics analysis showed that airway resistance decreased by 42%, and pressure drop was reduced by 43%. Intraluminal mucosal expansion was found with nasal obstruction in the physical model.

CONCLUSION

By decreasing the degree of bending and length at the nasal valve, inspiratory downstream nonoperated sites of the nasal cavity showed improvement in volume and airflow, suggesting that the nasal valve could play an oversized role in modulating the aerodynamics of the airway. This was confirmed with the physical model of nasal obstruction on downstream mucosa.

Creation of an idealized nasopharynx geometry for accurate computational fluid dynamics simulations of nasal airflow in patient-specific models lacking the nasopharynx anatomy

Virtual surgery planning based on computational fluid dynamics (CFD) simulations has the potential to improve surgical outcomes for nasal airway obstruction patients, but the benefits of virtual surgery planning must outweigh the risks of radiation exposure. Cone beam computed tomography (CT) scans represent an attractive imaging modality for virtual surgery planning due to lower costs and lower radiation exposures compared with conventional CT scans. However, to minimize the radiation exposure, the cone beam CT sinusitis protocol sometimes images only the nasal cavity, excluding the nasopharynx. The goal of this study was to develop an idealized nasopharynx geometry for accurate representation of outlet boundary conditions when the nasopharynx geometry is unavailable. Anatomically accurate models of the nasopharynx created from 30 CT scans were intersected with planes rotated at different angles to obtain an average geometry. Cross sections of the idealized nasopharynx were approximated as ellipses with cross-sectional areas and aspect ratios equal to the average in the actual patient-specific models. CFD simulations were performed to investigate whether nasal airflow patterns were affected when the CT-based nasopharynx was replaced by the idealized nasopharynx in 10 nasal airway obstruction patients. Despite the simple form of the idealized geometry, all biophysical variables (nasal resistance, airflow rate, and heat fluxes) were very similar in the idealized vs patient-specific models. The results confirmed the expectation that the nasopharynx geometry has a minimal effect in the nasal airflow patterns during inspiration. The idealized nasopharynx geometry will be useful in future CFD studies of nasal airflow based on medical images that exclude the nasopharynx.

Impact of Middle versus Inferior Total Turbinectomy on Nasal Aerodynamics

OBJECTIVES

This computational study aims to (1) use virtual surgery to theoretically investigate the maximum possible change in nasal aerodynamics after turbinate surgery, (2) quantify the relative contributions of the middle and inferior turbinates to nasal resistance and air conditioning, and (3) quantify to what extent total turbinectomy impairs the nasal air-conditioning capacity.

STUDY DESIGN

Virtual surgery and computational fluid dynamics.

SETTING

Academic tertiary medical center.

SUBJECTS AND METHODS

Ten patients with inferior turbinate hypertrophy were studied. Three-dimensional models of their nasal anatomies were built according to presurgery computed tomography scans. Virtual surgery was applied to create models representing either total inferior turbinectomy (TIT) or total middle turbinectomy (TMT). Airflow, heat transfer, and humidity transport were simulated at a steady-state inhalation rate of 15 L/min. The surface area stimulated by mucosal cooling was defined as the area where heat fluxes exceed 50 W/m(2).

RESULTS

In both virtual total turbinectomy models, nasal resistance decreased and airflow increased. However, the surface area where heat fluxes exceed 50 W/m(2) either decreased (TIT) or did not change significantly (TMT), suggesting that total turbinectomy may reduce the stimulation of cold receptors by inspired air. Nasal heating and humidification efficiencies decreased significantly after both TIT and TMT. All changes were greater in the TIT models than in the TMT models.

CONCLUSION

TIT yields greater increases in nasal airflow but also impairs the nasal air-conditioning capacity to a greater extent than TMT. Radical resection of the turbinates may decrease the surface area stimulated by mucosal cooling.

Simulating the nasal cycle with computational fluid dynamics

OBJECTIVES

(1) To develop a method to account for the confounding effect of the nasal cycle when comparing preoperative and postoperative objective measures of nasal patency. (2) To illustrate this method by reporting objective measures derived from computational fluid dynamics (CFD) models spanning the full range of mucosal engorgement associated with the nasal cycle in 2 subjects.

STUDY DESIGN

Retrospective.

SETTING

Academic tertiary medical center.

SUBJECTS AND METHODS

A cohort of 24 patients with nasal airway obstruction was reviewed to select the 2 patients with the greatest reciprocal change in mucosal engorgement between preoperative and postoperative computed tomography (CT) scans. Three-dimensional anatomic models were created based on the preoperative and postoperative CT scans. Nasal cycling models were also created by gradually changing the thickness of the inferior turbinate, middle turbinate, and septal swell body. Moreover, CFD was used to simulate airflow and to calculate nasal resistance and the average heat flux.

RESULTS

Before accounting for the nasal cycle, patient A appeared to have a paradoxical worsening nasal obstruction in the right cavity postoperatively. After accounting for the nasal cycle, patient A had small improvements in objective measures postoperatively. The magnitude of the surgical effect also differed in patient B after accounting for the nasal cycle.

CONCLUSION

By simulating the nasal cycle and comparing models in similar congestive states, surgical changes in nasal patency can be distinguished from physiological changes associated with the nasal cycle. This ability can lead to more precise comparisons of preoperative and postoperative objective measures and potentially more accurate virtual surgery planning.

Predicting postsurgery nasal physiology with computational modeling: current challenges and limitations

INTRODUCTION

High failure rates for surgical treatment of nasal airway obstruction (NAO) indicate that better diagnostic tools are needed to improve surgical planning. This study evaluates whether computer models based on a surgeon's edits of presurgery scans can accurately predict results from computer models based on postoperative scans of the same patient using computational fluid dynamics.

STUDY DESIGN

Prospective study.

SETTING

Academic medical center.

METHODS

Three-dimensional nasal models were reconstructed from computed tomographic scans of 10 patients with NAO presurgery and 5 to 8 months postsurgery. To create transcribed-surgery models, the surgeon digitally modified the preoperative reconstruction in each patient to represent physical changes expected from surgery and healing. Steady-state, laminar, inspiratory airflow was simulated in each model under physiologic, pressure-driven conditions.

RESULTS

Transcribed-surgery and postsurgery model variables were statistically different from presurgery variables at α = 0.05. Unilateral nasal resistance and airflow were not statistically different between transcribed-surgery and postsurgery models, but bilateral resistance was significantly different. Cross-sectional average pressures in transcribed surgery trended with postsurgery. Transcribed-surgery prediction errors of postsurgery bilateral resistance were within 10% to 20% and 20% to 30% in 5 and 4 subjects, respectively. Prediction errors for unilateral resistance were <10%, 10% to 20%, and 20% to 30% in 1, 2, and 4 subjects, respectively.

CONCLUSIONS

Computational models with modifications mimicking actual surgery and healing have the potential to predict postoperative outcomes. However, software to effectively translate virtual surgery steps into computational models is lacking. The ability to account for healing factors and the current limited virtual surgery tools are challenges that need to be overcome for greater accuracy.

Evaluation and reduction of nasal trauma

Nasal trauma plays a large and important role in the field of craniofacial trauma. The resulting aesthetic, structural, and functional sequelae associated with these injuries necessitate a thorough understanding of the topic. This includes an appreciation for the unique anatomic features of the region, the important aspects of the initial history and examination, nasal injury classification, and subsequent treatment timing and options. While a large body of literature has accumulated on the topic, the purpose of this article is to focus on both clinically relevant information and pearls of management. Additionally, age-specific concerns, secondary procedures, and nasal fracture grafting, will be addressed as well.