Influence of uncinate process on aerodynamic characteristics of nasal cavity and maxillary sinus / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>This study aimed to investigate the influence of uncinate process on air flow velocity, trace, distribution, air pressure, as well as the air flow exchange of nasal cavity and paranasal sinuses.</p><p><b>METHODS</b>Fluent software was used to simulate two nasal cavity and paranasal sinus structures following CT scanning, one had normal nasal cavity, the another had the nasal cavity with uncinate process removed. Air flow velocity, pressure, distribution and trace lines were calculated and compared by Navier-Stokes equation and numerically visualized between two models.</p><p><b>RESULTS</b>Air flow of two models in the common and middle meatus accounted for more than 50% and 30% of total nasal cavity flow. Flow velocity of two models were maximal in the common meatus, followed by the middle meatus. The maximal velocity existed on the left nasal district between limen nasi and head of inferior turbinate. The flow traces of two models were similar. In the normal model, the air flow velocity of the district around uncinate process was almost the same in inhale and exhale. In the model with the uncinate process removed, the air flow velocity of the district around uncinate process was faster, the air flow velocity in expiratory phase was quicker. Compared with the normal nasal cavity, there was more exchange of maxillary sinus in the model with cut uncinate process.</p><p><b>CONCLUSIONS</b>In the view of flow dynamics, the uncinate process effects the air flow velocity of the district around uncinate process and the exchange of maxillary sinus, the contribution of nasal flow is connected with the morphosis of the uncinate process.</p>

Effect of endoscopic sinus surgery on airflow of the nasal cavity and paranasal sinuses: a computational fluid dynamics study / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To study the airflow velocity, trace, distribution, pressure, as well as the airflow exchange between the nasal cavity and paranasal sinuses in a computer simulation of nasal cavity pre and post virtual endoscopic sinus surgery (ESS).</p><p><b>METHODS</b>Computational fluid dynamics (CFD) technique was applied to construct an anatomically and proportionally accurate three-dimensional nasal model based on a healthy adult woman's nasal CT scans. A virtual ESS intervention was performed numerically on the normal nasal model using Fluent 6.1.22 software. Navier-Stokes and continuity equations were used to calculate and compare the airflow characteristics between pre and post ESS models.</p><p><b>RESULTS</b>(1) After ESS flux in the common meatus decreased significantly. Flux in the middle meatus and the connected area of opened ethmoid sinus increased by 10% during stable inhalation and by 9% during exhalation. (2) Airflow velocity in the nasal sinus complex increased significantly after ESS. (3) After ESS airflow trace was significantly changed in the middle meatus. Wide-ranging vortices formed at the maxillary sinus, the connected area of ethmoid sinus and the sphenoid sinus. (4) Total nasal cavity resistance was decreased after ESS. (5) After ESS airflow exchange increased in the nasal sinuses, most markedly in the maxillary sinus.</p><p><b>CONCLUSIONS</b>After ESS airflow velocity, flux and trace were altered. Airflow exchange increased in each nasal sinus, especially in the maxillary sinus.</p>

Change of airflow patterns inside the maxillary sinus influenced by uncinate process / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>to study the change of the airflow patterns inside the maxillary sinus that influenced by uncinate process.</p><p><b>METHODS</b>Two kinds of cadavers were used, one had a normal uncinate process and the others had an out-gressin uncinate process. The airflow patterns inside the maxillary sinus were compared between them. Also compared were the airflow patterns inside the maxillary sinus before and after the excision of the uncinate process.</p><p><b>RESULTS</b>The airflow patterns inside the maxillary sinus in cadavers with a normal uncinate process exchanged actively. The smoke easily entered the maxillary sinus and could be found easily. It entered in the maxillary sinus with a whirlpool form. It cost about (11.4 +/- 1.4) s till the smoke dissipated from the maxillary sinus. On the other hand, in cadavers with an out-gressin uncinate process, the airflow patterns inside the maxillary sinus exchanged inductively. The smoke entered in the maxillary sinus and could be observed, but it was less than that in cadavers with a normal uncinate process. The form of the smoke could not be judged. It cost (24.2 +/- 1.6) s till the smoke dissipated from the maxillary sinus. The airflow patterns inside the maxillary sinus became inactive after the excision of the uncinate process in all kinds of cadavers.</p><p><b>CONCLUSIONS</b>The normal uncinate process permits the physiological commutation of air inside the maxillary sinus.</p>

Model of nasal cavity and paranasal sinuses created for studying the dynamics of the nasal airflow / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To create a model from an adult cadaver's nasal cavity and verify whether it can be used to study the airflow dynamics in the nasal cavity and paranasal sinuses.</p><p><b>METHODS</b>(1) The model was made by the material of transparent resin and Bengal gelatin according to a nasal cast of a cadaver. (2) The model was check by Acoustic Rhino-meter, CT scan and nasal endoscope, then compared with the normal. (3) To observe the smoke flow in the model and record it by a digital camera</p><p><b>RESULTS</b>It was succeeded in creating a model of the nasal cavity and paranasal sinus. The model was good at simulation and transparency. The structure of the model, the cross-sectional areas of the nasal passage and the CT scan results of the model were similar to the normal. The airflows in the model could be recorded by a digital camera. It showed that there were two types of airflows in the nose. The majority of airflows were found in the common and middle nasal meatus, the little part of the airflows passed through the upper of the nose like a parabola. There was an increasing proportion of airflows in the olfactory region when elevated the airflow rates. A relatively large vortex formed in the upper part of the nose, just behind the nasal valve, and another one was in the pharynx nasals.</p><p><b>CONCLUSIONS</b>(1) The transparent resin and Bengal gelatin are suitable for making the model of the nose. The model can be used to study the airflows dynamics of the nasal cavity and paranasal sinuses. (2) The majority of inspired airflows go straightly to the pharynx nasals through the combined middle and inferior airways, a little part of inspired airflows through the olfactory region like a parabola. (3) The inspired airflows first arrived at the front position of the middle and inferior turbinate. The airflows can go into the maxillary sinus, a vortex can be see in the maxillary sinus during breath.</p>