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

Abstract

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.

Numerical simulation of two consecutive nasal respiratory cycles: toward a better understanding of nasal physiology

“…Also, in front of the concavity of the nasal septum deviation, the turbinate is hypertrophied to compensate for the empty space between the lateral and medial walls of the nasal cavity. Such compensation leads to a normalization of airflow . This hypertrophy is probably a physiologic mechanism to maintain airflow parameters at a rate that provides the perception of good nasal comfort.…”

Sinonasal Risk Factors for the Development of Invasive Fungal Sinusitis in Hematological Patients: Are they Important?

“…26 Although the fluid dynamics of the nasal cavity are not completely known, some studies have pointed out that the greatest airflow and the greatest air turbulence during normal inspiration develop in the limited area between the nasal septum and middle turbinate. 26–28 Consequently, this area may be the initial point of accumulation of the fungal spores. This hypothesis could explain the finding of a middle turbinate involvement at the beginning of the IFS course.…”

“…Furthermore, some anatomic anomalies, such as anterior septum deviation, could create or increase an airflow turbulence facilitating fungal spore deposition. 28,29 Finally, the associated nasal obstruction leads to impaired ventilation with consequent inflammation and alteration of mucociliary clearance. 26,27 The association between the site of the infection and the site of the anatomic alteration in all of the cases in our study is another finding that supports this hypothesis and the unilaterality at the onset of IFS.…”

Strukturelle Besonderheiten der Nase brachyzephaler Hunderassen in der Computertomographie

“…Ve rmutlich treten beibrachyzephalen Hunden, und insbesondere beim Mops, starkeDeviationen derN asenscheidewand regelmäßig auf. Vo m Menschen istbekannt, dass Septumdeviationen durchden erhöhten Luftwiderstand auf der konvexen Seite zu Obstruktionender Naseführen.Auf derkonkavenSeite kommt es zu einerHypertrophie derNasenmuscheln (11). Ähnlichesbeobachtenwir in unse-rerUntersuchung.…”