A comparison of the nasal cross-sectional areas and volumes obtained with acoustic rhinometry and magnetic resonance imaging

Quantifying the Subjective Experience of Nasal Obstruction: A Review

Nasal obstruction is an exceedingly common problem and challenging to treat due to its multifactorial etiology. Therefore, measuring treatment outcomes of nasal obstruction can be equally complex yet vital to appropriately assessing symptom improvement or resolution. Both physiologic and anatomic assessments of the nasal airway exist in addition to validated patient-reported outcome measures (PROMs), which objectify subjective nasal obstruction and sinonasal symptoms. Correlation between objective and subjective treatment outcome measures is controversial with clinical guidelines favoring the use of PROMs for surgical treatment of nasal obstruction. In this review, the anatomic and physiologic measurements of the nasal airway and validated PROMs will be discussed, as well as the rationale for implementing PROMs into the rhinoplasty surgeon's practice.

A life off the beaten track in biomechanics: Imperfect elasticity, cytoskeletal glassiness, and epithelial unjamming

Textbook descriptions of elasticity, viscosity, and viscoelasticity fail to account for certain mechanical behaviors that typify soft living matter. Here, we consider three examples. First, strong empirical evidence suggests that within lung parenchymal tissues, the frictional stresses expressed at the microscale are fundamentally not of viscous origin. Second, the cytoskeleton (CSK) of the airway smooth muscle cell, as well as that of all eukaryotic cells, is more solid-like than fluid-like, yet its elastic modulus is softer than the softest of soft rubbers by a factor of 104-105. Moreover, the eukaryotic CSK expresses power law rheology, innate malleability, and fluidization when sheared. For these reasons, taken together, the CSK of the living eukaryotic cell is reminiscent of the class of materials called soft glasses, thus likening it to inert materials such as clays, pastes slurries, emulsions, and foams. Third, the cellular collective comprising a confluent epithelial layer can become solid-like and jammed, fluid-like and unjammed, or something in between. Esoteric though each may seem, these discoveries are consequential insofar as they impact our understanding of bronchospasm and wound healing as well as cancer cell invasion and embryonic development. Moreover, there are reasons to suspect that certain of these phenomena first arose in the early protist as a result of evolutionary pressures exerted by the primordial microenvironment. We have hypothesized, further, that each then became passed down virtually unchanged to the present day as a conserved core process. These topics are addressed here not only because they are interesting but also because they track the journey of one laboratory along a path less traveled by.

Olfactory Evaluation in Clinical Medical Practice

The subjective and demanding nature of olfactory testing means that it is often neglected in clinic despite loss of smell leading to significant limitations in everyday life. The list of diseases associated with loss of olfaction far exceeds the field of otorhinolaryngology and can also be seen in neurodegenerative disorders. Knowledge of possible clinical testing is essential to determine a proper differential diagnosis for the loss of olfactory sense. Causes of olfactory impairment can be divided into either failure in transferring odour to the organ of perception or damage to the olfactory pathway structure itself. Examination should therefore include methods evaluating cross-sectional area and patency of the nasal cavity as well as subjective or objective assessment of olfactory function. In this report we summarize several articles, studies, and our own experiences to provide a comprehensive review of their current clinical usage including their benefits, limitations, and possible outcomes. We also discuss the mechanism of olfaction step by step to provide a full understanding of the possible errors depending on the localization in the pathway and the methods designed for their detection. We discuss the correlation of the microbiome in nasal polyposis and chronic rhinitis with olfactory impairment using objective olfactometry. The topic of objective olfactometry and the examination of olfactory event-related potentials (OERP) is commented upon in detail.

Reliability of Acoustic Pharyngometry and Rhinometry Examination in Children and Adolescents

OBJECTIVES

The aim of this cross-sectional study was to examine the method error and reliability of acoustic pharyngometry and rhinometry in children and adolescents and to describe the feasibility of these methods in a young population.

MATERIAL AND METHODS

The study sample included 35 healthy subjects in the age of 9 to 14 years. The subjects were randomly recruited for the present project in the period from June 2021 to February 2022. Repeated measurements of the upper airway dimensions in standing mirror position were performed by the use of Acoustic Pharyngometer and Rhinometer. Volume (cm³), calculated resistance (cm H₂O/L/min), mean area (cm²), minimum cross-sectional area (MCA, cm²) and distance to MCA (cm) were examined. Method errors and reliability coefficients were evaluated using Dahlberg's formula and the Houston reliability coefficient. The feasibility of the methods were analysed using paired t-test and estimated by difference in drop-out rates.

RESULTS

No systematic error exhibited in the repeated measurements except volume in the left nostril (P = 0.017). The method errors of the acoustic pharyngometry and rhinometry were betweeen 0.0002 to 0.069 and 0.001 to 0.082 respectively. The Houston reliability coefficient for both methods were between 0.952 to 0.999. The acoustic pharyngometry was significantly more feasible compared to rhinometry (P < 0.001).

CONCLUSIONS

The study shows that acoustic pharyngometry and rhinometry in the standing mirror position are reliable methods, with acoustic pharyngometry being even more feasible than rhinometry, which is why it is recommended to practice the methods with children and ensure reliability of results before registering measurements.

Mastery of Basic Rhinology: An Important Tool for the Modern Rhinoplasty Specialist

Rhinology is the branch of medicine that deals with nasal function as part of the respiratory apparatus. It is a fundamental component of otolaryngology curricula and thus generously found in that specialty's literature. Ear, nose, and throat specialists who have made aesthetic rhinoplasty a cornerstone of their practice have understood the importance of rhinology for years. We propose that deeper knowledge and understanding of rhinology would be incredibly useful for the cosmetic rhinoplasty surgeon, especially the one who has no formal training in otolaryngology. This is of critical importance because sometimes, cosmetic rhinoplasties may have negative repercussions on nasal function, a problem that must be dealt with either preemptively at the time of surgery or at a revision procedure. Moreover, many of today's rhinoplasty patients are seeking comprehensive surgical care by a specialist who can manage both aesthetic and functional concerns in a single operation.

Evaluation of Nasal Patency Among Patients With Unilateral Cleft Lip and Palate: Cleft Versus Non-Cleft Side

OBJECTIVE

To evaluate the nasal patency using acoustic rhinometry (AR) in patients with unilateral cleft lip and palate (UCLP) and to ascertain the rhinological importance of the same.

METHODS

Eccovision Acoustic Rhinometer system was used for assessment of nasal cross-sectional area (CSA) and volume in 15 patients with UCLP. The CSA1, CSA2, and CSA3, which represent the CSA at the nasal valve area and anterior end of the inferior turbinate, the anterior half of the inferior turbinate and the anterior end of the middle turbinate, and the region of middle portion of middle turbinate, respectively, were compared on the cleft and non-cleft side.

RESULTS

The mean ± SD of CSA1, CSA2, and CSA3 as well as the overall nasal CSA were significantly higher on non-cleft side compared to cleft side (P value < .001). The mean ± SD of nasal volume was also significantly higher in non-cleft side compared to cleft side (P value < .001).

CONCLUSIONS

The nasal patency among patients with UCLP demonstrates a range of impairments that can be objectively measured using acoustic rhinometry. The orthodontic, orthopedic, or orthosurgical management of maxillary deficiency in these patients can affect the nasal area and volume and can have an impact on breathing, speech, and sleep. The pretreatment assessment may be useful to identify patients who are at potential risk of deterioration of nasal patency and airway post-intervention. Taking into consideration the multiple diagnostic procedures in the course of long-term multidisciplinary treatment of patients with cleft lip and palate, a noninvasive investigation technique such as AR may be the preferred mode of investigation to ascertain nasal patency.

In silico approaches to respiratory nasal flows: A review

The engineering discipline of in silico fluid dynamics delivers quantitative information on airflow behaviour in the nasal regions with unprecedented detail, often beyond the reach of traditional experiments. The ability to provide visualisation and analysis of flow properties such as velocity and pressure fields, as well as wall shear stress, dynamically during the respiratory cycle may give significant insight to clinicians. Yet, there remains ongoing challenges to advance the state-of-the-art further, including for example the lack of comprehensive CFD modelling on varied cohorts of patients. The present article embodies a review of previous and current in silico approaches to simulating nasal airflows. The review discusses specific modelling techniques required to accommodate physiologically- and clinically-relevant findings. It also provides a critical summary of the reported results in the literature followed by an outlook on the challenges and topics anticipated to drive research into the future.

Impact of Distraction Osteogenesis Maxillary Expansion on the Internal Nasal Valve in Obstructive Sleep Apnea

OBJECTIVE

To assess the effect of distraction osteogenesis maxillary expansion (DOME) on objective parameters of the internal nasal valve and correlate findings with subjective outcomes.

STUDY DESIGN

Retrospective cohort study.

SETTING

Tertiary referral center.

SUBJECTS AND METHODS

After Institutional Review Board approval, included subjects were those with obstructive sleep apnea, had undergone DOME from September 2014 to April 2018, and had cone beam computed tomography scans available before and after expansion. Measurement of the internal nasal valve parameters was performed with Invivo6 Software (version 6.0.3). Interrater reliability of all pre- and postexpansion parameters was measured. Patient-reported outcome measures included the Nasal Obstruction and Septoplasty Effectiveness Scale (NOSE) and Epworth Sleepiness Scale scores, and correlation between objective and subjective outcomes were evaluated by Spearman correlation analysis.

RESULTS

Thirty-two subjects met inclusion criteria. All showed significant improvement in their subjective outcomes as well as an increase in their internal valve parameters. Significant correlation was observed between increased angles and improvement in postexpansion NOSE score (right angle, P = .024; left angle, P = .029).

CONCLUSION

DOME widens the internal nasal valve objectively (dimensions), which correlates significantly with subjective improvement (NOSE scores).

Measuring Nasal Obstruction Outcomes

Methods of measuring nasal obstruction outcomes include both objective anatomic and physiologic measurements, as well as subjective patient-reported measures. Anatomic measurements include acoustic rhinometry, imaging studies, and clinician-derived examination findings. Physiologic measures include rhinomanometry, nasal peak inspiratory flow, and computational fluid dynamics. Patient-reported outcome measures (PROMs) are self-reported assessments of disease-specific quality-of-life outcomes. Several studies attempted correlation of these outcome measures; however, few show strong correlation. Expert opinion favors determining successful surgical outcomes using PROMs. This review provides a summary of current nasal obstruction outcome measures.

The Reliability of Polyvinylidene Fluoride Sensor for Intra- and Intersession Measurements

A new nasal sensor has been designed using Polyvinylidene fluoride (PVDF) film using its piezoelectric property to measure nasal patency. The aim of this study is to determine the intra- and intersession reliability of the new PVDF nasal sensor measurement of unilateral and combined nasal parameters in a group of healthy subjects. Two identical nasal sensors: for right nostril (RN) and left nostril (LN) were designed using piezoelectric natured PVDF films. Twenty subjects were studied. To evaluate the repeatability, total three sets of PVDF sensor measurements were recorded, two sets were taken 5 min apart during same session without repositioning the PVDF nasal sensors and two more sets were taken during 1 h apart successively, by repositioning the PVDF nasal sensor. Intraclass correlation coefficients (ICC) of PVDF sensor measurements for intra- and intersession showed a high and greater repeatability over time for all the combined (mean) and unilateral (RN and LN) values. In both healthy and patients, ICC values for both intra- and intersession measurements were ≥ 0.80 confirming strong reliability and also almost all of the coefficients of variation for the same parameters were low (below 10%). PVDF sensor measurements showed good intra- and intersession repeatability and can be recommended for the objective monitoring of nasal patency during diagnosis and follow-up of conditions.

Inspiratory and Fixed Nasal Valve Collapse: Clinical and Rhinometric Assessment

Background

Acoustic rhinometry (AR) has been used to assess nasal valve obstruction. Standard AR measurement of the cross-sectional area (CSA) of the nasal valve is done in the apneic phase, whereas collapse often occurs on inspiration. We used the ratio of the CSA obtained during active inspiration and during apnea to compute a more meaningful method of diagnosing nasal valve collapse.

Methods

AR was performed in 40 patients without nasal valve obstruction and 47 patients diagnosed with nasal valve obstruction. Patients with septal deflection or anterior inferior turbinate hypertrophy were excluded. The internal and external nasal valve area was observed during apnea and on active inspiration. AR measurement of the CSA of both nasal valves was performed during the apneic phase and during active inspiration and the CSA (inspiratory)/CSA (apneic) ratio was calculated.

Results

The CSA (inspiratory)/CSA (apneic) ratio was ≥1 in normal patients and in patients with fixed nasal valve collapse. The ratio was <1 in patients with inspiratory collapse. Data from history, physical examination, and dual-mode AR testing successfully differentiated patients into (1) normal valves, (2) fixed valve collapse, and (3) inspiratory valve collapse. A large number of patients with collapse had both internal and external valve obstruction and a large number also had a combination of inspiratory and fixed collapse.

Conclusion

Dual-mode AR testing is an effective tool in more precisely identifying nasal valve obstruction and is the first objective test shown to be highly diagnostic of inspiratory nasal valve collapse.

Effects of Anatomical Variations of the Nasal Cavity on Acoustic Rhinometry Measurements: A Model Study

Background

The goal of this study was to assess how anatomic variations of the nasal cavity affect the accuracy of acoustic rhinometry (AR) measurements.

Methods

A cast model of a human nasal cavity was used to investigate the effects of the nasal valve and paranasal sinuses on AR measurements. A luminal impression of a cadaver nasal cavity was made, and a cast model was created from this impression. To simulate the nasal valve, inserts of varying inner diameter were placed in the model nasal passage. To simulate the paranasal sinuses, side branches with varying neck diameters and cavity volumes were attached to the model.

Results

The AR measurements of the anterior nasal passage were reasonably precise when the passage area of the insert was within the normal range. When the passage area of the insert was reduced, AR measurements significantly underestimated the cross-sectional areas beyond the insert. The volume of the paranasal sinus had limited effect on AR measurements when the sinus ostium was small. However, when the ostium size was large, increasing the volume of the sinus led to significant overestimation of AR-derived areas beyond the ostium.

Conclusion

The pathologies that narrow the anterior nasal passage result in the most significant AR error by causing area underestimation beyond the constriction. It also appears that increased paranasal sinus volume causes overestimation of areas posterior to the sinus ostium when the ostium size is large. If these physical effects are not considered, the results obtained during clinical examination with AR may be misinterpreted.

When static meets dynamic: Comparing cone-beam computed tomography and acoustic reflection for upper airway analysis

INTRODUCTION

Upper airway measurement can be important for the diagnosis of breathing disorders. Acoustic reflection (AR) is an accepted tool for studying the airway. Our objective was to investigate the differences between cone-beam computed tomography (CBCT) and AR in calculating airway volumes and areas.

METHODS

Subjects with prescribed CBCT images as part of their records were also asked to have AR performed. A total of 59 subjects (mean age, 15 ± 3.8 years) had their upper airway (5 areas) measured from CBCT images, acoustic rhinometry, and acoustic pharyngometry. Volumes and minimal cross-sectional areas were extracted and compared with software.

RESULTS

Intraclass correlation on 20 randomly selected subjects, remeasured 2 weeks apart, showed high reliability (r >0.77). Means of total nasal volume were significantly different between the 2 methods (P = 0.035), but anterior nasal volume and minimal cross-sectional area showed no differences (P = 0.532 and P = 0.066, respectively). Pharyngeal volume showed significant differences (P = 0.01) with high correlation (r = 0.755), whereas pharyngeal minimal cross-sectional area showed no differences (P = 0.109). The pharyngeal volume difference may not be considered clinically significant, since it is 758 mm³ for measurements showing means of 11,000 ± 4000 mm³.

CONCLUSIONS

CBCT is an accurate method for measuring anterior nasal volume, nasal minimal cross-sectional area, pharyngeal volume, and pharyngeal minimal cross-sectional area.

A UK survey of current ENT practice in the assessment of nasal patency

BACKGROUND

Nasal obstruction is a common ENT complaint; however, decisions on its management are challenging, with high rates of dissatisfaction following surgery. This study investigated the practice of UK clinicians in the evaluation of nasal patency.

METHOD

Seventy-eight UK-based rhinologists were surveyed at the 2015 British Academic Conference in Otolaryngology.

RESULTS

Clinical history and examination are almost universally used to evaluate nasal blockage. The most commonly used test was the nasal misting pattern (73 per cent), followed by peak nasal inspiratory flow (19 per cent). The Sino-Nasal Outcome Test 22 or 23 was utilised by 29 per cent of respondents. Sixty-three per cent of respondents reported that a lack of equipment was the principle reason for not using objective measures, followed by time constraints and a lack of correlation with symptom scores.

CONCLUSION

British clinicians rely on clinical skills to evaluate nasal blockage. There is a desire for a simple, non-invasive device that objectively measures airflow for nasal breathing during physiological resting and correlates with subjective symptom scores.

A deformable template method for describing and averaging the anatomical variation of the human nasal cavity

Background

Understanding airflow through human airways is of importance in drug delivery and development of assisted breathing methods. In this work, we focus on development of a new method to obtain an averaged upper airway geometry from computed tomography (CT) scans of many individuals. This geometry can be used for air flow simulation. We examine the geometry resulting from a data set consisting of 26 airway scans. The methods used to achieve this include nasal cavity segmentation and a deformable template matching procedure.

Methods

The method uses CT scans of the nasal cavity of individuals to obtain a segmented mesh, and coronal cross-sections of this segmented mesh are taken. The cross-sections are processed to extract the nasal cavity, and then thinned (‘skeletonized’) representations of the airways are computed. A reference template is then deformed such that it lies on this thinned representation. The average of these deformations is used to obtain the average geometry. Our procedure tolerates a wider variety of nasal cavity geometries than earlier methods.

Results

To assess the averaging method, key landmark points on each of the input scans as well as the output average geometry are located and compared with one another, showing good agreement. In addition, the cross-sectional area (CSA) profile of the nasal cavities of the input scans and average geometry are also computed, showing that the CSA of the average model falls within the variation of the population.

Conclusions

The use of a deformable template method for aligning and averaging the nasal cavity provides an improved, detailed geometry that is unavailable without using deformation.

Electronic supplementary material

The online version of this article (doi:10.1186/s12880-016-0154-8) contains supplementary material, which is available to authorized users.

Magnetic resonance imaging reveals the complementary effects of decongestant and Breathe Right Nasal Strips on internal nasal anatomy

OBJECTIVES/HYPOTHESIS

This magnetic resonance imaging (MRI) study of 26 subjects with nasal congestion was performed to assess in the complete nasal passage both the anatomical effect of the marketed Breathe Right Nasal Strip (BRNS) relative to placebo and the potential adjunctive effect of using a decongestant in combination with the BRNS.

STUDY DESIGN

Randomized, crossover study.

METHODS

The study consisted of two parts, the first involving application of either the BRNS or the placebo strip in a randomized, crossover design with evaluator blinding, and repeated MRI scanning; and the second a sequential process of decongestant administration, MRI scanning, application of the BRNS, and repeated MRI. The same anatomical MRI protocol was used throughout. Nasal patency was assessed in the whole nasal passage and eight subregions (by inferior-superior, anterior-posterior division). Numerical response scores representing subjective nasal congestion were also obtained.

RESULTS

Results demonstrate significant anatomical enlargement with the BRNS relative to placebo (P < .001), as well as an additive effect of using a decongestant in combination with the BRNS; both supported by a strong and significant negative correlation with the subjective nasal response measures of nasal congestion (r = -0.98, P = .002). Furthermore, analysis of the nasal subregions indicates that this adjunctive effect arises from a partially localized action of the complementary products: the BRNS acting primarily anteriorly in the nose and the decongestant mainly posteriorly.

CONCLUSIONS

The BRNS alone significantly increases nasal patency and alleviates perceived nasal congestion, and additional relief of symptoms can be obtained with simultaneous use of a decongestant.

LEVEL OF EVIDENCE

1b. Laryngoscope, 126:2205-2211, 2016.

Using magnetic resonance imaging to quantify the inflammatory response following allergen challenge in allergic rhinitis

Current rhinometric and flow assessments measure nasal patency and are often poorly correlated with rhinitis symptoms. To evaluate magnetic resonance imaging (MRI) as a new method to measure inflammatory changes in nasal and sinus mucosa following nasal allergen challenge. A pilot study (n = 6) determined the optimal technical settings for MRI to measure inflammatory change which were then adopted for the main study. This study was a single blind, placebo‐controlled, three‐way crossover trial in 14 subjects with seasonal allergic rhinitis. Effects of cetirizine, cetirizine and pseudoephedrine (Cet+PE), or placebo on total nasal symptom scores (TNSS), peak nasal inspiratory flow (PNIF), nasal nitric oxide (nNO), acoustic rhinometry, and MRI end points following nasal intranasal allergen challenge were measured. There were significant changes in all parameters after allergen challenge (P < 0.01), except for nNO. MRI end points were less variable and more consistent than PNIF and acoustic rhinometry in detecting changes after allergen challenge. Total nasal airspace volume was the most sensitive and reproducible MRI measurement, with a mean reduction from −5.37 cm³ (95%CI −7.35, −3.38; P < 0.001), which was maximal 60 min after allergen challenge. A change of one in TNSS corresponded to a change in MRI volume of −0.57 cm³. There was an improvement in all parameters (except nNO) in subjects taking Cet+PE compared with placebo, however this did not achieve significance probably because of the small study size (overall analysis P > 0.07; comparison of active versus placebo P > 0.09). MRI provides novel insights into the anatomical inflammatory changes post allergen challenge and provides a new method for assessment of nasal patency and objective measurement of inflammatory responses.

What are some tips and pearls for preserving and improving nasal function when performing a cosmetic rhinoplasty?

PURPOSE OF REVIEW

Understanding nasal form and function is critical in performing successful cosmetic rhinoplasty. Careful evaluation of the patient's nasal airway with identification of areas of existing or potential obstruction is important in avoiding potential pitfalls that may compromise nasal function following rhinoplasty. This article will review surgical techniques that can be utilized to preserve and improve nasal function during cosmetic rhinoplasty.

RECENT FINDINGS

Recent literature on nasal functionality focuses on the management of the internal and external nasal valve as well as the nasal septum during rhinoplasty.

SUMMARY

Successful cosmetic rhinoplasty requires a thorough preoperative analysis of both aesthetic and functional characteristics of the nose. Close attention should be paid to the internal and external nasal valves and nasal septum before and during surgery to preserve and improve nasal function following cosmetic rhinoplasty.

Vocal tract dimensional characteristics of professional male and female singers with different types of singing voices

The present study examined the possible relationship between classification of professional singing voices and their vocal tract parameters including vocal tract length and volume, and vowel formant frequencies. Acoustic reflection technology (ART) was used to measure vocal tract length and volume of 107 professional singers: 32 tenors, 25 baritones, 27 sopranos, and 23 mezzo-sopranos. The first three formant frequencies (F1-F3) of the English vowels /a, æ, i/ produced by the professional singers were also obtained. Results indicated significantly shorter oral and vocal tract length, and smaller oral and vocal tract volume associated with sopranos when compared with mezzo-sopranos. Acoustically, sopranos had higher F1, F2, and F3 values than mezzo-sopranos. The present findings suggest that, in addition to vocal tract length, vocal tract volume may also affect formant frequencies, implying the possibility that classifying professional singing voices is based on both vocal tract length and volume information.

Correlation between nasal resistance and different acoustic rhinometry parameters in children and adolescents with and without allergic rhinitis

Acoustic rhinometry and rhinomanometry are important tests used to assess nasal function. The degree to which the parameters of these tests are correlated is yet to be established.

Objective

This paper aimed to study the correlations between nasal resistance (NR) and acoustic rhinometry parameters in children and adolescents with allergic rhinitis and controls.

Method

Twenty patients with allergic rhinitis and 20 controls were enrolled. NR, volumes (V4, V5, V2-5), and minimal cross-sectional areas (MC1, MC2) were measured in three moments: baseline, after induction of nasal obstruction and after topical decongestant administration.

Results

Patients with allergic rhinitis had significant correlation between NR and all volumes (V5: r = -0.60) and with MC2. Among controls, MC1 was the parameter with the strongest correlation with NR at baseline (r = -0.53) and after decongestant administration. In the combined analysis, V5 had the highest correlation coefficients at baseline (r = -0.53), after obstruction (r = -0.58) and after decongestant (r = -0.46).

Conclusions

Our data showed that NR and acoustic rhinometry parameters have negative and significant correlations. Nasal volumes are, in general, better correlated than minimal cross-sectional areas. V5 was the parameter with the highest correlation in the rhinitis group and in the combined analysis.

Intersession repeatability of acoustic rhinometry measurements in healthy volunteers

Objectives

Acoustic rhinometry is a rapid, reliable and non-invasive technique for the evaluation of conditions associated with impaired nasal patency. This study aimed to examine the intersession repeatability of acoustic rhinometry measurements of unilateral and combined nasal parameters in a group of healthy volunteers.

Methods

Twenty healthy volunteers were studied. In each subject, acoustic rhinometry measurements were performed on five consecutive days, with multiple recordings. Five clinically relevant parameters were measured in each session and the intersession repeatability of these measurements was expressed in terms of mean coefficient of variation, intraclass correlation coefficient and inter-item correlations.

Results

Intraclass correlation coefficients showed a high, and greater repeatability over time for all the combined (mean) values compared to the unilateral values. All intraclass correlations for combined values were ≥0.80 confirming almost perfect agreement. All intraclass correlations and inter-item correlations were associated with P<0.001. The mean coefficient of variation was low (<10%) for all but the proximal minimum cross sectional area (MCA1) measurements.

Conclusion

Acoustic rhinometry provides highly repeatable measurements of nasal patency, which is best for combined (mean) nasal parameters. This property makes it suitable for use in the diagnosis and follow-up of conditions associated with nasal obstruction, either structural or functional.

Does cosmetic rhinoplasty affect nose function?

Objective. To evaluate the changes in nasal dimensions of healthy Iranian volunteered for cosmetic rhinoplasty after surgery using acoustic rhinometry. Methods. Pre- and postoperative nasal dimension of 36 cases undergoing cosmetic rhinoplasty were compared using acoustic rhinometry (AR), and the measured variables were distance to first and second constriction (d1, d2), first and second minimal cross-sectional area (MCA1, 2), and volume. Results. Mean age (SD) of cases were 24.63 (4.4) years. Septoplasty was performed in 12 cases (33.3%). After surgery, bilateral d1 and both MCA2 decreased significantly, while significant increase was observed in MCA1 postoperatively using decongestant. Cases with septoplasty experienced more increase in MCA1 and less constriction in MCA2 postoperatively. In cases with rhinoplasty alone, they received benefit from double osteotomy in MCA1. In either group of rhinoplasty with and without septoplasty, placing a strut was beneficial for patients. Discussion. The cross-sectional area of the nose is a major factor in the determination of airflow. Cosmetic rhinoplasty may generate a mix effect on nose function. Performing osteotomy may better help patients to save nasal patency, septoplasty is beneficial even in mildly deviated septums, and placing a strut may be beneficial in most of the cases.

The role of three-dimensional CT in the evaluation of nasal structures and anomalies

Traditionally, computed tomography (CT) is the primary radiographic method to analyze the morphology of the craniofacial bones: Because of the many overlapping anatomical structures, it is difficult and sometimes impossible to evaluate craniofacial bones three-dimensionally (3D) with these images. For this reason, the aim of this paper has been to evaluate and demonstrate the importance of CT scans integrated by three-dimensional reconstructions (3D-CT) volume rendering imaging for the accurate understanding of the nasal pyramid morphology in the evaluation of patients submitted to secondary rhinoseptoplasty. Twenty patients enrolled for a secondary rhinoseptoplasty, underwent a preoperative evaluation through 3D-CT volume rendering imaging. This technique allowed a prefect reconstruction of the nasal structures at the level of the valve, as well as the medial and lateral walls of the nasal fossa in all of its components (bone and cartilage). In our experience, the 3D-CT volume rendering imaging studies improve the preoperative evaluation of structures and anomalies which are hard to evaluate by the anterior rhinoscopy and/or nasal endoscopy: alar and lateral cartilages, interdomal distance, tip morphology, valvular configuration, loss of bone-cartilaginous substance, etc. All of these points are important during the preoperative planning of secondary rhinoseptoplasty.

[Surgically assisted rapid maxillary expansion. Effects on the nasal airways and nasal septum]

BACKGROUND

Surgically assisted rapid maxillary expansion (SARME) is a standardized method to treat cross bites in maxillofacial surgery. Changes to the nasal airways are assumed due to the anatomic dependence between the palate and the nasal floor.

PATIENTS AND METHODS

In this study 19 patients with a transverse deficit of the upper jaw underwent SARME. CT scans were performed 1 month pre- and 6 months postoperatively. Effects to the lower nasal airways, the nasal septum and the hard palate were subsequently evaluated.

RESULTS

The mean distraction width of the upper jaws was 5.84 mm (SD 2.19) postoperatively. In addition to the dentoalveolar gain in width, a significant increase in the nasal floor was observed (p<0.001). The anterior part of the nasal floor was increased by 14.11%. An anterior-caudal tilt of the upper jaw was observed in the anterior part measuring 1.5 mm (SD 1.05). No significant deviation of the nasal septum occurred.

CONCLUSION

SARME has a significant effect on ear, nose and throat medicine. Nasal airways enlarge significantly, while no significant deviation of the nasal septum is observed.

Vocal tract dimensional development of adolescents: an acoustic reflection study

OBJECTIVE

The purpose of the study was to investigate the effects of age and gender on adolescents' vocal tract dimensional development with acoustic reflection technology (ART).

METHODS

A total of ninety-five male and female adolescents aged between 10 and 18 divided into three age groups were tested with acoustic reflection technology (ART) and acoustic program to secure their vocal tract dimensional parameters and the vowel formant frequencies.

RESULTS

Significant age and gender effects were found not only in vocal tract length, but also segmental volumetric measurements, as well as the vowel formant frequencies.

CONCLUSIONS

The findings of this study have provided insights on the developmental trend of adolescents' vocal tracts. The study has also offered a preliminary anatomical database of adolescents' vocal tract dimensional growth for otolaryngologists, clinical anatomists, speech therapists and other health professionals of swallowing, respiration and communicative disorders.

Surgical treatment of nasal obstruction in rhinoplasty

Often, rhinoplasty patients present not just for aesthetic correction, but for improvement of their nasal breathing due to functional abnormalities or problems. Because the aesthetic and functional problems must be addressed together, an understanding of both the internal and external anatomy is essential. In this article, the authors review the differential diagnosis of nasal obstruction and the important components of a thorough examination. In this article, medical treatment options are not discussed, but just as an exacting aesthetic analysis leads to an appropriate cosmetic rhinoplasty plan, a thorough functional analysis will dictate the appropriate medical or surgical treatment.

Nasal valve: anatomy and physiology

The anterior portion of the nasal cavities, from the nostril to the nasal valve (NV), is the place of highest nasal resistance to airflow, paramount to nasal physiology. There are different terminologies for the same anatomic structures in the literature.

Aim

The aim of this paper was to study the NV function and define clearly the structures of the anterior portion of the nasal cavities, mainly the region of the NV.

Conclusion

Internum ostium is the anterior segment and isthmus nasi is the posterior segment of the NV region.

Quantification of vocal tract configuration of older children with Down syndrome: a pilot study

OBJECTIVE

To quantify the vocal tract (VT) lumen of older children with Down syndrome using acoustic reflection (AR) technology.

DESIGN

Comparative study.

SETTING

Vocal tract lab with sound-proof booth.

PARTICIPANTS

Ten children (4 males and 6 females), aged 9-17 years old diagnosed with Down syndrome. Ten typically developing children (4 males and 6 females) matched for age, gender, and race.

INTERVENTION

Each participant's vocal tract measurements were obtained by using an Eccovision Acoustic Pharyngometer.

MAIN OUTCOME MEASURES

Six vocal tract dimensional parameters (oral length, oral volume, pharyngeal length, pharyngeal volume, total vocal tract length, and total vocal tract volume) from children with Down syndrome and the typically developing children were measured and compared.

RESULTS

Children with Down syndrome exhibited small oral cavities when compared to control group (F(1,18)=6.55, p=0.02). They also demonstrated a smaller vocal tract volumes (F(1,18)=2.58, p=0.13), although the results were not statistically significant at the 0.05 level. Pharyngeal length, pharyngeal volume, and vocal tract length were not significantly different between the two groups.

CONCLUSION

Children with Down syndrome had smaller oral cavities, and smaller vocal tract volumes. No significant differences were found for pharyngeal length, pharyngeal volume, and vocal tract length between these two groups.

Long term effects of surgically assisted rapid maxillary expansion without performing osteotomy of the pterygoid plates

PURPOSE

Surgically assisted rapid maxillary expansions (SARME) are commonly used to widen the maxilla. This study evaluates long term stability of surgically assisted rapid palatal expansion without performing osteotomy of the pterygoid plates and its effects on nasal airway volume.

MATERIALS AND METHODS

13 patients (mean age 31, 23+/-6, 11) with a maxillary transverse deficit of at least 5mm were examined 1 month before and on average 63 months after a mean palatal distraction of 8.29+/-1.68mm by acoustic rhinometry. Profiles of the nasal airway volumes were collected. A cast model analysis was performed. The data were evaluated using Wilcoxon signed rank test.

RESULTS

A V-shaped movement of the segments was observed. The gain for total nasal volume was 23.25%. Findings indicate a significant enhancement of nasal volume in all patients (P<0.01) as result of the maxillary expansion. No relapse occurred in the study group.

CONCLUSION

SARME provides a long term stable orthodontic bite correction and permanently enhances the nasal airways. A transverse shift of the segments can be achieved over the whole bony palate even when no osteotomy of the pterygo-maxillary suture is performed.

Endoscopic sinus surgery in the management of nasal obstruction

Nasal obstruction is the leading symptom observed among patients who have chronic rhinosinusitis (CRS) with or without nasal polyposis. After failure of medical therapy, functional endoscopic sinus surgery (FESS) has emerged as the preferred treatment of CRS. Interestingly, although patient-reported outcomes show unequivocal relief of nasal obstruction after FESS, studies measuring nasal airflow and resistance demonstrate more modest improvements. This article provides an overview of the physiology of nasal airflow sensation, the burden of nasal obstruction in patients who have CRS, and the efficacy of FESS in addressing nasal obstruction in this population. Additionally, advances in airflow modeling that may enable improved preoperative planning for the relief of nasal obstruction after FESS are discussed.

Diagnosis of nasal airway obstruction

Nasal airway obstruction is the source of significant patient discomfort and financial burden; hence, otolaryngologists encounter this symptom on an almost daily basis. This article provides a thorough yet concise summary of common and more specialized techniques that are instrumental in diagnosing nasal obstruction. The article begins with a brief overview of significant nasal anatomy and physiology. Ultimately, the main focus is on exploring the role of nasal endoscopy, radiographic imaging, acoustic rhinomanometry and other diagnostic tests that assist in the diagnosis of nasal airway obstruction.

Válvula nasal: anatomia e fisiologia

A porção anterior das cavidades nasais, da narina à válvula nasal (VN), é a região de maior resistência nasal ao fluxo aerífero, de suma importância para a fisiologia nasal. Na literatura existem terminologias diferentes para se referir às mesmas estruturas anatômicas e, ainda, o mesmo termo se referindo a estruturas anatômicas diferentes. OBJETIVO: Realizamos este trabalho com o objetivo de revisarmos o funcionamento da VN e definirmos com mais clareza estruturas anatômicas da porção anterior das cavidades nasais, principalmente a região da VN. CONCLUSÃO: Existe controvérsia na literatura quanto à nomenclatura das estruturas da VN. Neste trabalho definimos VN como uma estrutura tridimensional compreendida anteriormente pelo ostium internum e posteriormente pelo isthmus nasi.

Creation of a standardized geometry of the human nasal cavity

A novel, standardized geometry of the human nasal cavity was created by aligning and processing 30 sets of computed tomography (CT) scans of nasal airways of healthy subjects. Digital three-dimensional (3-D) geometries of the 60 single human nasal cavities (30 right and 30 mirrored left cavities) were generated from the CT scans and measurements of physical parameters of each single nasal cavity were performed. A methodology was developed to scale, orient, and align the nasal geometries, after which 2-D digital coronal cross-sectional slices were generated. With the use of an innovative image processing algorithm, median cross-sectional geometries were created to match median physical parameters while retaining the unique geometric features of the human nasal cavity. From these idealized 2-D images, an original 3-D standardized median human nasal cavity was created. This new standardized geometry was compared against the original geometries of all subjects as well as limited existing data from the literature. The new model has potential for use as a geometric standard in future experimental and numerical studies of deposition of inhaled aerosols, as well as for use as a reference during diagnosis of unhealthy patients. The specific procedure developed could also be applied to build standard nasal geometries for different identifiable groups within the larger population.

Optimising nasal spray parameters for efficient drug delivery using computational fluid dynamics

Experimental images from particle/droplet image analyser (PDIA) and particle image velocimetry (PIV) imaging techniques of particle formation from a nasal spray device were taken to determine critical parameters for the study and design of effective nasal drug delivery devices. The critical parameters found were particle size, diameter of spray cone at a break-up length and a spray cone angle. A range of values for each of the parameters were ascertained through imaging analysis which were then transposed into initial particle boundary conditions for particle flow simulation within the nasal cavity by using Computational Fluid Dynamics software. An Eulerian-Lagrangian scheme was utilised to track mono-dispersed particles (10 and 20 microm) at a breathing rate of 10 L/min. The results from this qualitative study aim to assist the pharmaceutical industry to improve and help guide the design of nasal spray devices.

Effects of the Cottle's maneuver on the nasal valve as assessed by acoustic rhinometry

BACKGROUND

The nasal valve is the narrowest segment of the nasal cavity and plays an essential role in breathing. There has been plenty of discussion in the literature concerning the location and function of the nasal valve. The Cottle's maneuver (CM) is a test in which the cheek on the side to be evaluated is gently pulled laterally with one to two fingers to open the valve. This test is used to determine if the most significant site of nasal obstruction is at the valve or farther inside the nasal cavity. The aim of this study was to determine the dimensional changes caused by the CM in the nose as measured by acoustic rhinometry (AR).

METHODS

Eight adult volunteers with no nasal symptoms were recruited and their nasal cavities were measured by AR. The measurements were done with and without the CM both before and after decongestion with a mixture of 1:1000 epinephrine and 4% lidocaine in cotton pledgets. The MCA1 and MCA2 and their distances from the nostril, as well as the volume-measured from the zero point to the MCA2 point--were determined.

RESULTS

The main effect of the CM was a mean increase in MCA1 by 33% (p = 0.001) and 44% (p < 0.001) before and after decongestion, respectively. The distance of MCA1 increased significantly, because of the CM, by 12% (p = 0.006) before and 7% (p = 0.008) after decongestion. The percentage increases in volume were 33% (p = 0.001) and 44% (p < 0.001), respectively. Decongestion of the nasal mucosa induced a statistically significant (p = 0.001) increase in both MCA1 (by 21%) and MCA2 (by 28%).

CONCLUSION

The CM significantly increased MCA1 in AR, and the increase was more evident after decongestion of the nasal mucosa. The changes in MCA2 were nonsignificant. We conclude that the value of the CM in investigating a possible valve insufficiency may be greater if the nose is studied both before and after decongestion of the nasal mucosa.

Objective monitoring of nasal patency and nasal physiology in rhinitis

Nasal obstruction can be monitored objectively by measurement of nasal airflow, as evaluated by nasal peak flow, or as airways resistance/conductance as evaluated by rhinomanometry. Peak flow can be measured during inspiration or expiration. Of these measurements, nasal inspiratory peak flow is the best validated technique for home monitoring in clinical trials. The equipment is portable, relatively inexpensive, and simple to use. One disadvantage, however, is that nasal inspiratory peak flow is influenced by lower airway as well as upper airway function. Rhinomanometry is a more sensitive technique that is specific for nasal measurements. The equipment, however, requires an operator, is more expensive, and is not portable. Thus, it is applicable only for clinic visit measures in clinical trials. Measurements require patient cooperation and coordination, and not all can achieve repeatable results. Thus, this objective measure is best suited to laboratory challenge studies involving smaller numbers of selected volunteers. A nonphysiological measure of nasal patency is acoustic rhinometry. This sonic echo technique measures internal nasal luminal volume and the minimum cross-sectional area. The derivation of these measures from the reflected sound waves requires complex mathematical transformation and makes several theoretical assumptions. Despite this, however, such measures correlate well with the nasal physiological measures, and the nasal volume measures have been shown to relate well to results obtained by imaging techniques such as computed tomography scanning or magnetic resonance imaging. Like rhinomanometry, acoustic rhinometry is not suitable for home monitoring and can be applied only to clinic visit measures or for laboratory nasal challenge monitoring. It has advantages in being easy to use, in requiring little patient cooperation, and in providing repeatable results. In addition to nasal obstruction, allergic rhinitis is recognized to be associated with impaired mucociliary clearance and altered nasal responsiveness. Measures exist for the monitoring of these aspects of nasal dysfunction. Although measures of mucociliary clearance are simple to perform, they have a poor record of reproducibility. Their incorporation into clinical trials is thus questionable, although positive outcomes from therapeutic intervention have been reported. Measures of nasal responsiveness are at present largely confined to research studies investigating disease mechanisms in allergic and nonallergic rhinitis. The techniques are insufficiently standardized to be applied to multicenter clinical trials but could be used in limited-center studies to gain insight into the regulatory effects of different therapeutic modalities.

Evaluation of upper airway obstruction--an ENT perspective

Upper airway obstruction is a common clinical problem. Nasal obstruction can be the result of nasal anatomy, mucosal swelling, or acquired blockage. The anatomy of the upper airway differs from the lower because of the presence of erectile tissue in the nose. Measurement of nasal airway obstruction can be performed with video endoscopic photo-documentation, rhinomanometry, nasal inspiratory peak flow, visual analog scales, and psychometric validated questionnaires.

Acoustic rhinometry in the practice of allergy

OBJECTIVE

To provide a comprehensive practical overview of the use of acoustic rhinometry in the practice of allergy.

DATA SOURCES

An all-inclusive PubMed search was conducted for articles on acoustic rhinometry that were published in peer-reviewed journals, between 1989 and 2006, using the keywords acoustic rhinometry, allergic rhinitis, and nasal provocation testing.

STUDY SELECTION

The expert opinion of the authors was used to select studies for inclusion in this review.

RESULTS

Acoustic rhinometry is a sound-based technique used to measure nasal cavity area and volume. It has been validated by comparison to measurements with computed tomography and magnetic resonance imaging. Acoustic rhinometry requires minimal patient cooperation and may be used in adults, children, and infants. It is used by medical practitioners to diagnose and evaluate therapeutic responses in conditions such as rhinitis and to measure nasal dimensions during allergen provocation testing. Acoustic rhinometry also provides a visual reflection of the nasal response to therapy, which may be useful in increasing compliance to prescribed medications.

CONCLUSIONS

Acoustic rhinometry is a safe, noninvasive, objective, and validated measure of nasal obstruction that appears to be of practical use in the diagnosis and management of inflammatory diseases of the upper airways.

Physiological change in nasal patency in response to changes in posture, temperature, and humidity measured by acoustic rhinometry

BACKGROUND

Acoustic rhinometry has been used to assess nasal patency and to calculate nasal cavity volume. This study used acoustic rhinometry to assess changes in nasal patency after alterations in posture, unilateral mechanical obstruction, temperature, and humidity.

METHODS

Eight healthy adult volunteer subjects underwent acoustic rhinometry during the following conditions: (1) sitting position (control), (2) supine position, (3) left lateral recumbent position, (4) nostril unilaterally mechanically blocked, (5) ice pack on neck, (6) drinking cold water, (7) drinking hot water, (8) nasal nebulizer, and (9) oxymetazoline decongestant.

RESULTS

Two distinct patterns emerged based on the total nasal cavity volumes in response to the decongestant. Subjects with initial unilateral nasal cavity volumes near the mean had an expected increase in total volume after the topical decongestant administration. There were two subjects with initial volumes of 1 SD above the mean that had a paradoxical decrease in total volume in response to the decongestant. In all subjects, there was a significant decrease in the volume of each of the nasal cavities in response to ingestion of hot water at 1 minute. There was a significant decrease in the volume of the smaller of the two nasal cavities in response to nebulizer treatment and hot water ingestion at 5 minutes. Total nasal cavity volume changes were not significant for any of the variables.

CONCLUSION

Changes in nasal cavity volumes were detected by acoustic rhinometry after alterations in posture, unilateral mechanical obstruction, temperature, and humidity. Nebulizer treatment and hot water ingestion caused a significant decrease in nasal volume. The nose of a healthy patient was able to adapt to environmental and physiological changes to maintain a consistent total nasal volume within 15 minutes.

Correlation between fiberoptic nasal endoscopy and acoustic rhinometry in adults without nasal complaints

BACKGROUND

Acoustic rhinometry indirectly calculates cross-sectional areas of the nose at various locations from the nostrils and the total volume of the nasal cavity. These parameters are calculated from an area-distance curve displayed by the device.

METHODS

Seventy-seven adults between the ages of 20 and 40 years who had no nasal complaints were examined by acoustic rhinometry and fiberoptic nasal endoscopy in an attempt to compare and correlate areas of nasal narrowing detected by these two methods.

RESULTS

The comparison between the distances to the various narrowed areas revealed a statistically significant correlation between the first three constrictions detected by acoustic rhinometry and the first three areas of anatomic narrowing measured by fiberoptic nasal endoscopy in both nares but no correlation between the fourth constriction and the fourth measurement on either side.

CONCLUSION

The results confirm an anatomic correlation between the two examination methods, identifying the first constriction as the nasal valve, the second constriction as the head of the inferior nasal turbinate, and the third constriction as the head of the middle turbinate. The fourth constriction did not correspond to the choanal region.

Normative standards for vocal tract dimensions by race as measured by acoustic pharyngometry

SUMMARY

Acoustic pharyngometry evaluates the geometry of the vocal tract with acoustic reflections and provides information about vocal tract cross-sectional area and volume from lip to the glottis. Variations in vocal tract diameters are needed for speech scientists to validate various acoustic models and for medical professionals since the advent of endoscopic surgical techniques. Race is known to be one of the most important factors affecting the oral and nasal structures. This study compared vocal tract dimensions of White American, African American, and Chinese male and female speakers. One hundred and twenty healthy adult subjects with equal numbers of men and women were divided among three races. Subjects were controlled for age, gender, height, and weight. Six dimensional parameters of the speakers' vocal tract cavities were measured with acoustic reflection technology (AR). Significant gender and race main effects were found in certain vocal tract dimensions. The findings of this study now provide speech scientists, speech-language pathologists, and other health professionals with a new anatomical database of vocal tract variations for adult speakers from three different races.

Comparison of anatomic, physiological, and subjective measures of the nasal airway

BACKGROUND

Studies comparing different categories of nasal measures have reported inconsistent results. We sought to compare validated measures of the nasal airway: anatomic (acoustic rhinometry), physiological (nasal peak inspiratory flow), and subjective experience (Nasal Obstruction Symptom Evaluation Scale and a visual analog scale [VAS]).

METHODS

This prospective cross-sectional study of 290 nonrhinologic patients included upright and supine rhinometry (minimum cross sectional area [MCA] and volume) and flow (mean and maximum) measurements, as well as subjective measures. Associations between measures were evaluated with Spearman correlations and multivariate linear regression, adjusting for age, sex, race, body mass index, and smoking history.

RESULTS

Correlations between objective (rhinometry and flow) and subjective categories of nasal measures ranged from -0.16 to 0.03 (mean correlation, -0.07 +/- 0.05), with 0 significant correlations of 16 tested. Correlations between anatomic (rhinometry) and physiological (flow) categories ranged from 0.04 to 0.15 (mean correlation, 0.10 +/- 0.03), with 0 significant correlations of 16 tested. In contrast, within each category (rhinometry, flow, and subjective), all correlations were significant (13 correlations, all p < 0.001) and ranged from 0.62 to 0.99. Of 16 adjusted associations between objective and subjective measures, 14 were not significant (p > 0.05); only upright and supine MCAs were significantly associated with the VAS (both, p < 0.05).

CONCLUSION

Validated anatomic, physiological, and subjective nasal measures may assess different aspects of the nasal airway and provide complementary information. Future studies should be directed at developing a composite measure including components from all three categories of nasal measurement.

Video-endoscopy and digital image analysis of the nasal valve area

The aim of this study was to evaluate the benefit of digital image analysis of video-endoscopic images of the valve area to study changes in cross-sections of the nasal valve area before and after nasal surgery. Fifty patients scheduled for septoplasty or septorhinoplasty were included. Successful recordings of the valve area and digitally calculated cross-sections of the nasal valve area served as main outcome measures. First, various endoscopes (rigid 0 degrees - and 25 degrees -endoscopes and fibreoptic 0 degrees -endoscope) were tested and video-endoscopy was standardised in 39 patients. Second, preoperative and postoperative images of the nasal valve area in 11 patients with obstruction of the nasal valve area were digitally analysed and compared. In these patients, a significant widening of the valve area could be shown postoperatively. We conclude that digital image analysis of the nasal valve area can be helpful in the measurement of cross-sections of the nasal valve area before and after nasal surgical procedures in selected patients.

Acoustic rhinometry: accuracy and ability to detect changes in passage area at different locations in the nasal cavity

OBJECTIVES

To evaluate the accuracy of acoustic rhinometry (AR) measurements, and to assess how well AR detects obstructions of various sizes at specific sites in the nasal cavity, we created a cast model from an adult cadaver nasal cavity.

METHODS

The actual cross-sectional areas of the cast model nasal passage were determined by computed tomography and compared with the corresponding areas measured by AR. To assess how nasal obstruction affects the AR results, we placed small wax spheres of different diameters at specific sites in the model (nasal valve, head of the inferior turbinate, head of the middle turbinate, middle of the middle turbinate, choana, and nasopharynx).

RESULTS

The AR-derived cross-sectional areas in the first 6.5 cm of the cast model nasal cavity were very close to the corresponding areas calculated from computed tomographic sections perpendicular to the presumed acoustic axis. However, AR overestimated the passage areas at locations posterior to the 6.5-cm point. Acoustic rhinometry gave an accurate indication of the passage area of the nasal valve and its distance from the nostril. The nasal valve and the choana were indicated by significant dips on the AR area-distance curve, whereas the curve was smooth throughout the region that included the head of the inferior turbinate, the head of the middle turbinate, the middle of the middle turbinate, and the nasopharynx. In other words, AR did not discretely identify these latter sites. Acoustic rhinometry detected the different-sized inserts (obstructions) more accurately at the nasal valve than at sites posterior to this location.

CONCLUSIONS

The results of the study show that AR is a valuable method for assessing the anterior nasal cavity. This technique is sensitive for detecting changes in passage area at the nasal valve region; however, the sensitivity is lower at sites posterior to this. The findings suggest that when there is substantial narrowing of the nasal valve, AR will not identify an obstruction at any location posterior to the nasal valve. In such situations, AR measurements beyond the abnormal nasal valve may easily lead to misinterpretation of the patient's nasal anatomy or condition.

Acoustic rhinometry: should we be using it?

PURPOSE OF THE REVIEW

The purpose of this review is to examine the role of acoustic rhinometry in clinical practice. Although acoustic rhinometry was first described for clinical use in 1989, it is not in common use today. Should we be using it? Yes. I think we should be using it more often. This review provides an update of the new standard for interpretation and expanded clinical uses.

RECENT FINDINGS

The most significant advances in the past year in this area have been the publication of standards for its clinical use. In addition, the repertoire of clinical problems that can be analyzed objectively with acoustic rhinometry has expanded to include turbinoplasty, sleep disorders, more types of cosmetic/reconstructive procedures, sinus surgery, vasomotor rhinitis, maxillofacial expansion procedures, and aspirin and methacholine challenge. (Its ability for pediatric disorders, such as adenoidectomy, has been reaffirmed.) Some case examples are included to demonstrate the utility of acoustic rhinometry for 'mixed' pathology.

SUMMARY

Acoustic rhinometry is a rapid, objective, painless, noninvasive technique for assessing nasal airway obstruction. Recently, standards have been developed that aid its expansion for clinical use. Expanded clinical applications include sleep disorders, cosmetic/reconstructive and maxillofacial disorders, sinus and turbinate procedures, and pediatrics. Acoustic rhinometry should be utilized to improve our ability to practice evidence-based medicine in rhinology.