A Dynamic and Direct Visualization Model for the Study of Nasal Airflow

Simmen, Daniel; Scherrer, José L.; Moe, Kris S.; Heinz, Benjamin

doi:10.1001/archotol.125.9.1015

Cited by 67 publications

(49 citation statements)

References 11 publications

(36 reference statements)

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“…A slow-circling eddy causing turbulence is seen and this can additionally increase the fl ow resistance ( fi g. 1 ). This turbulence can occur at low fl ow velocities and this may reduce the physiological part of laminar fl ow [16] .…”

Section: Discussionmentioning

confidence: 99%

First Findings Concerning Airflow in Noses with Septal Deviation and Compensatory Turbinate Hypertrophy – A Model Study

Grützenmacher¹,

Robinson

Gräfe³

et al. 2006

ORL

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Background: The nasal septal deviation is a common cause of nasal obstruction. On the other hand, many septal deviations are asymptomatic. It seems a physiological adaptation occurs on both sides. Septal deviation leads to internal nasal asymmetry, which in turn causes compensatory change in turbinate morphology (e.g. turbinate hypertrophy respectively hypotrophy). This mechanism is investigated with the help of fluid dynamic experiments and functional rhinologic diagnostics. Methods: Functional models of the nose (modified Mink’s boxes) were used and assessment was made by acoustic rhinometry and rhinoresistometry, followed by flow dynamic investigations. Septal deviations of varying position, together with turbinates of differing grades of hypertrophy, were simulated and assessed. Results and Conclusions: We observed in models of septal deviation an increase in flow resistance on the ipsilateral side as a result of friction of flow particles in the narrowing. Furthermore, on the opposite side of the deviation, the enlargement of the stream channel did not generally lead to a reduction in flow resistance, but rather to a ‘dead space’, where only a slow-circling eddy was observed. This eddy causes an increase in turbulence. In vivo turbinate hypertrophy occurs to fill this dead space, thereby reducing turbulent flow without a significant increase in resistance. In cases of moderate septal deviation, compensatory mechanisms of the turbinates can lead to a normalization of nasal airflow and surgical therapy would not be indicated. Deviations in the anterior part of the septum seem to be more symptomatic, because the mechanism is missing and due to the physiological narrowing of the nasal isthmus. To differ between physiologic and pathologic deviation, functional diagnostics are needed.

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Section: Discussionmentioning

confidence: 99%

First Findings Concerning Airflow in Noses with Septal Deviation and Compensatory Turbinate Hypertrophy – A Model Study

Grützenmacher¹,

Robinson

Gräfe³

et al. 2006

ORL

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“…Nasal airfl ow is almost exclusively turbulent in the functional area (region of nasal conchas) at a fl ow velocity of 100 ml/s (model A). This fact is an essential prerequisite for a suffi cient conditioning and acclimatization of ventilated air [12] .…”

Section: Discussionmentioning

confidence: 99%

The Nasal Airflow in Noses with Septal Perforation: A Model Study

Grützenmacher

Mlynski

Lang

et al. 2005

ORL

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Background: Septal perforation is a common clinical problem in rhinology. Affected patients suffer from a dry nose, crusts as well as recurrent epistaxis and sometimes an inspiratory whistle. The aim of this study was to investigate the underlying flow dynamic mechanisms. Methods: The physical flow effects of such pathologies were examined in functional nose models (box models) and anatomically exact models of the nose. Therefore, septal perforations of different sizes and localisations were studied in straight and deviated nasal septa. Results and Conclusions: It could be seen that the localisation of the perforation has no impact on the flow pattern. In large septal perforations, the air jet collides with the posterior edge of the perforation and disintegrates turbulently. Since airflow is physiologically turbulent in the posterior part of the nose, posterior perforations do not cause clinical complaints. The inspiratory whistling sound during respiration is based on the principle of a lip whistle. Large perforations do not cause a whistling sound. The necessary high flow velocity needed in large perforations is usually not achievable.

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“…For example, it has been shown that modifications of the volume of the anterior portion of the nasal cavity may lead to differences in odour thresholds or odour identification. 6,33 Minute changes of intranasal anatomy remote from the olfactory cleft may also produce significant changes of olfactory function 5,45 (see also 32 ). Additionally, recent work from Sobel and colleagues suggests that slight anatomical differences between the left and right nostrils, leading to lateralized differences in air-flow, may produce significant differences in perceived odour quality.…”

Section: Introductionmentioning

confidence: 99%

Perceptual differences between chemical stimuli presented through the ortho- or retronasal route

Hummel¹,

Heilmann²,

Landis

et al. 2005

Flavour Fragr. J.

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Orthonasal or retronasal presentation of certain odours in everyday life, such as cheese or fish, evokes different responses. To study this phenomenon, stimulation techniques were developed to allow ortho-or retronasal presentation of chemosensory stimuli. Based on this technique, several studies were performed to investigate: (a) the subjects' ratings of stimulus intensity, hedonic characteristics of the stimuli, and stimulus quality; (b) the peripherally obtained electro-olfactogram; (c) EEG-derived olfactory event-related potentials; and (d) cerebral activation using functional magnetic resonance imaging; additional experiments investigated (e) the differential sensitivity of the nasal mucosa to trigeminal stimuli; and finally (f) clinical observations were obtained from patients with nasal polyposis with regard to ortho-or retronasal presentation of chemosensory stimuli. Summarizing these results, the studies indicate that there are perceptual differences in relation to ortho-and retronasal stimulus presentation. They appear to relate to: (i) contextual effects; (ii) subtle differences in nasal airflow, therefore access of stimuli to the olfactory epithelium may play a role in perceptual differences; in addition (iii) differential trigeminal sensitivities of the respiratory epithelium, possibly in combination with (iv) differential wiring of olfactory receptor neurons, may contribute to the observed differences in the perception of stimuli presented through the ortho-or retronasal routes.

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A Dynamic and Direct Visualization Model for the Study of Nasal Airflow

Abstract: This model allows the investigation of airflow distribution and turbulence under physiologic conditions and the examination of the influence of pathologic conditions on these parameters. Overzealous trimming of turbinates results in an unphysiologic distribution of airflow.

Cited by 67 publications

References 11 publications

First Findings Concerning Airflow in Noses with Septal Deviation and Compensatory Turbinate Hypertrophy – A Model Study

First Findings Concerning Airflow in Noses with Septal Deviation and Compensatory Turbinate Hypertrophy – A Model Study

The Nasal Airflow in Noses with Septal Perforation: A Model Study

Perceptual differences between chemical stimuli presented through the ortho- or retronasal route

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