Nasal Cavity Geometry Research Articles

Nasal Airway Measurements in Children Treated by Rapid Maxillary Expansion

Rapid maxillary expansion is an orthodontic procedure that is commonly used to widen the maxilla. It is generally admitted that this technique is effective to correct palate narrowing, whereas there has not been agreement on the effect of this procedure in nasal parameters. The availability of a reliable and objective technique to assess the geometry of nasal cavities, such as acoustic rhinometry, stimulated the present investigation. Twenty-seven children, undergoing rapid maxillary expansion, were evaluated by rhinomanometry and acoustic rhinometry. Postero-anterior radiographs were taken in 15 patients for cephalometric measurements. Examinations were performed before expansion treatment and after 12 month follow-up and compared to the measurements obtained from an untreated control group. With regard to rhinomanometry, we recorded a significant reduction in nasal airway resistance (NAR) after the orthodontic procedure only in decongestion. Using acoustic rhinometry, we found a significant increase in total minimum cross-sectional areas (TMCA) and total nasal volume (TNV) after the expansion both in basal and decongested conditions. Also, nasal cavity width and interzygomatic distance had a significant mean increase after the treatment. Comparison of measures between the control group and the treated group showed that the increase in TMCA and TNV, as well as the decrease in NAR, were significantly greater in the treated group in both basal and decongested conditions. We demonstrated that rapid maxillary expansion is an effective procedure in widening nasal cavities with respect to an untreated control group and that the reported improvement in nasal breathing after palatal expansion, is a consequence of an increase in nasal size.

Pre and post functional endoscopic sinus surgery nasal cavity volume assessment by acoustic rhinometry

SummaryAcoustic rhinometry is an objective method to determine nasal cavity geometry. The technique is based on sound wave reflexion analysis in the nasal cavity, and determines crossectional areas as a function of distance as well as volume.AimThe purpose of this study is to analyse nasal cavity volume changes caused by functional endoscopic sinus surgery (FESS) in adults with chronic rhinosinusitis by acoustic rhinometry, and to correlate these changes with improvements in the sensation of nasal obstruction.Material and MethodForty patients aged from 18 to 73 years were prospectively evaluated between August and October 1999 at the Graz University Hospital, Austria. All patients were diagnosed with chronic rhinosinusitis, and undertook acoustic rhinometry before and after FESS.Scientific designA clinical prospective study.ResultsThe nasal cavity total volume increased significantly after surgery. Nasal obstruction was improved in 88% of the patients, 20% with partial improvement and 68% with total improvement. There was no correlation between volume increase and improvement of the sensation of nasal obstruction.ConclusionTotal nasal cavity volume significantly increased after surgery; however, there was no correlation between volume increase and improvements of nasal obstruction. No significant pre or postoperative increase in total nasal cavity volume after decongestion were observed.

Techniques d’étude pharmacologique et clinique de l’obstruction nasale : application à la xylométazoline

Nasal obstruction, a prominent feature of rhinitis, may be quantified in humans by haemodynamic techniques (measuring local blood flux), static methods (measuring the geometry of nasal cavities) and dynamic methods (assessing the patency of nasal airways through the measure of resistance to air flow). These methods demonstrated the nasal decongestant activity of xylometazoline in healthy volunteers and rhinitis patients. Controlled double-blind studies established the clinical efficacy of xylometazoline in infectious and allergic (seasonal and perennial) rhinitis versus placebo and in comparison with various reference substances. The effects on nasal epithelium ciliary activity which are observed in vitro are modest and even less pronounced in vivo owing to dilution in situ and protective physiological processes.

Nasal cavity dimensions in guinea pig and rat measured by acoustic rhinometry and fluid-displacement method

The purpose of the study was to measure nasal passageway dimensions in guinea pigs and rats by use of acoustic rhinometry (AR) and by a previously described fluid-displacement method (FDM) (Straszek SP, Taagehoej F, Graff S, and Pedersen OF. J Appl Physiol 95: 635-642, 2003) to investigate the potential of AR in pharmacological research with these animals. We measured the area-distance relationships by AR of nasal cavities postmortem in five guinea pigs (Duncan Hartley, 400 g) and five rats (Wistar, 250 g) by using custom-made equipment scaled for the purpose. Nosepieces were made from plastic pipette tips and either inserted into or glued onto the nostrils. We used liquid perfluorocarbon in the fluid-displacement study, and it was carried out subsequent to the acoustic measurements. We found for guinea pigs that AR measured a mean volume of 98 mm(3) (95-100 mm(3)) (mean and 95% confidence interval) of the first 2 cm of the cavity. FDM measured a mean volume of 146 mm(3) (117-175 mm(3)), meaning that AR only measured 70% (50-90) of the volume by FDM. For rats, the volume from 0 to 2 cm was 58 mm(3) (55-61 mm(3)) by AR and 73 mm(3) (60-87 mm(3)) by FDM, resulting in AR only measuring 83% (66-100%) of volume by FDM (see Table 2). We conclude that absolute nasal cavity dimensions are underestimated by AR in guinea pigs and rats. This does not preclude that relative changes may be correctly measured. In vivo trials with AR using rats have not yet been published. The FDM is possibly the most accurate alternative to AR for measurements of the nasal cavity geometry in small laboratory animals, but it can only be used postmortem.

Comparison of Feline Nasal Cavity Dimensions Measured by Acoustic Rhinometry and Nasal Casts

The goal of this study was to evaluate the relationship between feline nasal cavity geometry determined in vivo by acoustic rhinometry (AR(in vivo)) and by nasal cavity casts. Cast cross-sectional areas were measured by acoustic rhinometry (AR(cast)), a fluid-displacement method (FDM), and slicing. A volume comparison between AR(in vivo) and AR(cast) was studied in cats with varying degrees of nasal obstruction after application of phenylpropanolamine, saline, or compound 48/80. After measurements of AR(in vivo), impression material was injected into the nasal cavity to produce casts. Subsequently, the cross-sectional areas of the nasal impressions were measured by AR(cast) and FDM using ethanol. All casts were weighed to determine exact volume. Six casts also were sliced into segments of equal thickness for determination of cross-sectional area. Cast volume determined by AR(cast) was consistent with results obtained using FDM and weight. Volumes of the first 3 cm determined by AR(in vivo) ranged between 78 +/- 9% of cast volumes determined by AR(cast) for decongested cavities and 16 +/- 15% for congested cavities. AR(in vivo) does not reflect cast geometry, probably because of (1) underestimation by AR because of methodological problems caused by the cavity geometry, (2) deformation of compliant structures within the nasal passageways resulting from the casting procedure, and/or (3) the casting material reaches parts of the nasal cavity not accessible to sound, e.g., sinuses or recesses. Nevertheless, this study does not preclude the use of AR as a sensitive method suited to evaluate relative changes in nasal volume caused by experimental challenges of the nasal mucosa. Compared with AR(in vivo), casts still may be of use but it is less sensitive to measure relative changes after experimental challenge.

Acoustic Rhinometry in Measuring Nasal Volumes

Objectives: Acoustic rhinometry is used to objectively measure the minimal cross sectional area and volumes of nasal cavities. However, data for healthy subjects reported in Taiwan are few. Therefore, we wanted to establish the normal range among healthy adults and to evaluate the changes after nasal decongestion. Methods: We included 20 males and 25females in this study (mean age: 25.1years; age range: 19 to 40 years). An acoustic rhinometer was used to evaluate the first minimal cross sectional area (MCAI), the distance from the tip of the probe to the first minimal cross sectional area (D1), the second minimal cross sectional area (MCA2), the distance from the tip of the probe to the second minimal cross sectional area (D2), the volume between the tip of the nosepiece and 3 cm into the nasal cavity (VO3), the volume of the nasal cavity between 2 to5cm from the tip of the nosepiece (V25), the volume of the nasal cavity between 4 to 7 cm from the tip of the nosepiece (V47), and the volume between the tip of the nosepiece and 7 cm into the nasal cavity (VO7). These measurements were taken before and after nasal decongestion. Results: Data acquired from the male group before decongestion were as follows: MCAI: 0.74±0.12 (cm2); D1: 0.35±0.25(cm); MCA2: 0.61±0.27 (cm2); D2: 2.30±0.29 (cm); V03: 2.38±0.45(cm3); V25: 3.73±1.64 (cm3); V47: 6.46± 3.69 (cm3); VO7: 10.19±4.43 (cm3); data acquired from the female group before decongestion were: MCAI: 0.62 ± 0.15 (cm2); Dl: 0.56± 0.43 (cm); MCA2: 0.67 ± 0.28 (cm2); D2: 2.33± 058 (cm); V03: 2.13±0.46 (cm3); V25: 3.93±2.16 (cm3); V 47: 7.89 ± 4.38 (cm3); V07: 11.48±5.48 (cm3). The increase in MCA2 after nasal decongestion was significant (p＜ 0.001), both in females and males. The increases in V03, V25, V47 and V07 after nasal decongestion were statistically significant both in the female and male groups as well (p＜ 0.001). Conclusions: Acoustic rhinometry is a convenient method for assessing the geometry of the nasal cavity. The maximal effect of decongestion is found in the anterior and middle part of the nasal cavity, at the level of the inferior and middle turbinates.

Airflow simulation inside a model of the human nasal cavity in a virtual reality based rhinological operation planning system

The success rate of rhinological surgery is expected to be improved by changes of the nasal cavity geometry based on the assessment of the airflow via numerical simulation. Therefore, we are developing an operation planning system that combines Computational Fluid Dynamics (CFD) and Virtual Reality (VR) technology. In this paper, we introduce the system's design and a typical application. Results of a numerical simulation of the flow field in a model of the human nasal cavity are presented and compared with experimental data. The comparison shows a good agreement with the experimental findings.

Monitoring methods of nasal pathology

The importance of correct clinical and therapeutic monitoring of allergic rhinitis is understandable in the light of the social and economic impact of this pathology: its prevalence is over 10% of the total population all over the world. For the evaluation of the local nasal pathology we include: (1) anterior rhinoscopy, (2) active anterior rhinomanometry, (3) positioned acoustic rhinometry, (4) determination of mucociliary transport time, (5) specific nasal provocation test. Active anterior rhinomanometry allows reliable assessment of the nasal respiratory function, acoustic rhinometry shows the geometry of nasal cavity, mucociliary transport time is an indicator of the mucosa eutrophism. In our experience, the specific nasal provocation test is one of the most important tests in this field. It is more sensitive than the skin test and the radioallergosorbent test (RAST) in the asymptomatic phase and it is able to show organ allergies. In this study we review the importance of this test and the methodology we commonly use.

Semi-automatic segmentation of computed tomographic images in volumetric estimation of nasal airway.

The objective of this study was to determine nasal cavity volumes and cross-sectional profiles from segmented coronal high-resolution computed tomography (HRCT) images. Pathological mucosal changes and congenital sinonasal variants were quantitated and three-dimensional (3D) images for determining sinonasal airway diseases evaluated by using the new semiautomatic segmentation software, Anatomatic. Anterior to posterior cross-sectional profiles of the sinonasal airway were obtained from acoustic rhinometry and segmented coronal HRCT images and compared in five patients having complaints of nasal obstruction and chronic sinusitis. Results showed that accurate volumes of air spaces in the nasal cavity and paranasal sinuses were obtained. When compared, the cross-sectional profiles of the nasal cavities obtained from acoustic rhinometry and the segmentation technique were similar in the anterior portion, but differed in the posterior portion. The results obtained by coronal HRCT and segmentation were more reliable than those produced with acoustic rhinometry. 3D images acquired from segmented images were found to help make a good pre-operative assessment of the whole sinonasal compartment. Segmentation and volumetric analysis using the Anatomatic technique also proved to be well suited to the evaluation of the nasal cavity and paranasal sinus geometry in patients with sinonasal diseases.

鼻アレルギー患者に対する鼻閉の評価 Ａｃｏｕｓｔｉｃ Ｒｈｉｎｏｍｅｔｒｙによる検討

The evaluation of nasal obstruction is important for the treatment of perennial allergic rhinitis. Although, nasal resistance induced by rhinomanometry is useful, several authors have reported that nasal resistance is not correlated with the sensation of nasal obstruction.Acoustic rhinometry was introduced by Hilberg et. al. (1989) to assess the geometry of nasal cavity. The method, based on sound reflection analysis provides an estimate of the cross-sectional area of the nasal cavity as a function of the distance from the nostril. Recently, acoustic rhinometry has become popular in our country. The aim of this study was to evaluate changes in the nasal mucosa of patients with perennial allergic rhinitis and in normal subjects and to investigate the benefits of acoustic rhinometry.Ten normal subjects and 10 patients with perennial allergic rhinitis were measured by acoustic rhinometry before and after administration of a topical decongestant using an acoustic rhinometer (RHIN2100 SRE co. Denmark). Changes in the nasal volume (0.8-4.0cm) (0-7.0cm) and cross-sectional area (c-notch) were greater in patients than in normal subjects. However, the nasal volume and cross-sectional area in patients with perennial allergic rhinitis were the same as in normal subjects.These results suggest that the nasal mucosa of patients with perennial allergic rhinitis is more swollen than that of normal subjects. Moreover, measurements of nasal volume and nasal cross-sectional area are able to define the structure of the nasal cavity. These values can be utilized to evaluate baseline values and improvements when medications are administered.In conclusion, acoustic rhinometry is potentially useful for evaluating nasal physiology, especially in cases of allergic rhinitis.

Monitoring methods for local nasal immunotherapy.

When a patient is affected by specific vasomotor rhinopathy (allergic rhinitis), both perennial and seasonal, all the nasal functions are altered to various degrees. For this reason, in the evaluation of the efficacy of an antiallergic therapy we include: 1) anterior rhinoscopy; 2) active anterior rhinomanometry; 3) positioned acoustic rhinometry; 4) determination of mucociliary transport time; and 5) specific nasal provocation test. Active anterior rhinomanometry performed according to the directions of the International Committee on Standardization allows reliable assessment of the nasal respiratory function. Acoustic rhinometry is an objective method to assess the geometry of nasal cavities but, as a new method, needs more standardization with particular care in connecting the nose-piece to the nostril. Both these tests performed before and after local administration of nasal decongestants allow quantification of the congestion degree of the nasal mucosa. Determination of mucociliary transport time, according to the method of coloured tracer, is easy to perform and may be considered a reliable indicator of the mucosa eutrophism. In our clinical experience we have often found mucociliary transport times delayed or even blocked, especially in patients affected by perennial allergic rhinitis. According to our experience the specific nasal provocation test is one of the most important tests in this field: it is more sensitive than skin tests and RAST in the asymptomatic phase and it is able to show organ allergies. In this paper we review the importance of this test, the methodology we currently use as well as changes after local nasal immunotherapy.

Acoustic Rhinometry in the Diagnosis of Occupational Rhinitis

Acoustic rhinometry (ARM) has been used to study the nasal cavity geometry and the response in nasal provocations. However, the use of ARM in the diagnosis of occupational rhinitis (OR) has not been reported. The purpose of this study was to find an ARM parameter and a limit value that could be used in provocation tests to express an objective change in the nasal cavity geometry. We used a new calculated parameter, Volume MCA%, for describing the change in the nasal geometry. Volume MCA% is the mean of the percentile changes of nasal volumes and minimal cross-sectional areas in a provocation test. We recommend a decrease of at least 15% in Volume MCA% for the limit of an essential change in the nasal cavity.

Nasal response to inhaled histamine measured by acoustic rhinometry in infants

Aerosolized histamine, delivered via a face mask, is commonly used to evaluate bronchial responsiveness in infants. To investigate nasal response to inhaled histamine we have measured nasal passage geometry in 32 infants by the use of acoustic reflections. Satisfactory data were obtained from only 17 infants (12 males, 5 females, 6.6 +/- 4.4 months), because of awakening prior to completing the study in the remaining 15 infants. Acoustic rhinometry provided nasal cavity volume at 4 cm from the entrance of the nostril (V04), the minimum cross-sectional area (Amin), and the distance from the nostril to Amin (Dmin). Nasal geometry and lung function (maximum expiratory functional residual capacity [VmaxFRC] were measured before and immediately after a histamine challenge test using rapid thoratic compression. The histamine aerosols decreased both VO4 and Amin significantly by a mean of 17% and 13%, respectively (P < 0.001). There was a small, but significant increase (mean = 0.19 cm) of Dmin in the right side only, indicating a posterior dislocation of the narrowest site with swelling of the mucous membrane. In general, we found a dose-response relationship in grouped data, with a greater fall in VO4 with increasing dose of histamine, but there was no correlation between percent fall in VO4 and VmaxFRC. This pilot study suggests that histamine aerosol affects nasal cavity geometry and that of acoustic rhinometry in infants and children warrants further investigation.

Acoustic rhinometry: validation of volume changes following intra-nasal polypectomy.

Acoustic rhinometry measures nasal cavity geometry by analysis of reflected acoustic impulses. Previously, the technique has been applied to normals, patients with septal deviations and rhinitis and to monitor the medical treatment of nasal polyps. To date, no study has been published to validate the application of this technique where nasal polyps are present. In this study, acoustic rhinometry has been used to assess the change in nasal cavity volume following intra-nasal polypectomy in 20 subjects. The volumes of the polyps removed surgically were measured by displacement and compared with the volume change recorded by acoustic rhinometry. A correlation of r = 0.59 (P = < 0.01) has been obtained. Therefore, it is possible to apply acoustic rhinometry as a method of assessing non-surgical treatment of nasal polyps given certain conditions.

Posture and nasal geometry.

The influence of posture on nasal cavity geometry was studied by acoustic rhinometry in 14 normal adult subjects. On adopting a supine position from sitting the volume of the initially more patulous nasal cavity decreased and the volume of the less patulous side increased. These changes in volume are statistically significant (p = less than 0.01).