The Analysis With The Character Of Self-adaptation To The Nasal Construction In Patients With Nasal Septum Deviation

Objective: The aim of the paper is to analysis the different characters of nasal airflow-field between 10 patients with nasal septum deviation and 20 healthy Chinese people through the method of 3-D reconstruction of these people's nasal airway,and then consider it's function when analyzing the relationship between the structure and function of human nose, to establish a model of self-adaptation to human nasal construction.Methods: The three-dimensional,finite-element mesh used in the calculation is developed from Spiral CT imaging scans of the nose of 10 pations with nasal septum deviation and 20 heathy people. The scans provide coronal images of the nose. while the main purpose of the reconstruction is to furnish a grid on which the finit element equations can be solved.The flow of air is described by the Navier-Stokes and continuity equations.The following conditions are imposed on the spatial boundaries of the flow field:1. A no-slip condition is imposed at the surface of the nasal airway walls.2. A standard atmosphere stress condition is established at the inlet.3. A velocity vector is specified at the outlet (nasopharynx) , which is obtained under the condition of inspiratory flow rate (10L/min).The finite-element method obtain solutions to the full Navier-Stokes and continuity equations within each element of the finite-element mesh,and we analysis the different characters of nasal airflow-field between the two groups of people.Results:1. In inspiratory, the airflow for patients with nasal septum group (experimental group) deviation mainly pass though the broad nasal cavity , especially in the middle part of meatus of nose.For heathy people group (control group), there is obvious difference of the airflow between the two sides of the nasal cavity in 16 cases(left11,right5) , which accounts for 80% of the total cases.In the mainly side of the nasal cavity, the airflow mainly passes through the middle and inferior part of the meatus of nose , then in the middle nasal meatus and inferior nasal meatus;in the no-mainly side , the airflow mainly passes the middle part of the meatus of nose . (1) .In the patients with nasal septem deviation group,the quantity of the airflow mainly passes though the broad nasal cavity,especially in the middle of the meatus of nose,it's equality between the two sides in the inferior part of the meatus of nose,middle nasal meatus,inferior nasal meatus and olfactory cleft . (2) . In the patients with nasal septem deviation group,the velocity of the airflow is rapid in the middle part of meatus of nose of the broad nasal cavity, it's equality between the two sides in the inferior part of the meatus of nose,middle nasal meatus,inferior nasal meatus and olfactory cleft. (3 ) .In the patients with nasal septem deviation group, the area of the nasal airway is larger in the broad nasal cavity, especially in the middle of the meatus of nose, it's area between the two sides in the inferior part of the meatus of nose,middle nasal meatus,inferior nasal meatus and olfactory cleft. (4) . in the heathy people group, the quantity of the airflow mainly passes though the mainly side, especially in middle and inferior part of the meatus of nose, it's equality between the two sides in the middle nasal meatus,inferior nasal meatus and olfactory cleft (5) .In the heathy people group, the velocity of the airflow is rapid in the middle and inferior part of the meatus of nose in mainly side , it's equality between the two sides in the middle nasal meatus,inferior nasal meatus and olfactory cleft. (6) .In the heathy people group, the area of the two side of the nasal cavity is equal.2. In inspiratory,the pressure drop from the anterior naris to the pharynx nasalis both in the two groups. in the heathy people group,the pressure drop mainly in the limen nasi, accounting approximately 58.78% of the total pressure drop in the whole nasal airway which is 131±91Pa; In the patients with nasal septem deviation group,the pressure mainly drop in the part of the nasal septum deviation, accounting approximately 71.36% of the total pressure drop in the whole nasal airway which is229±15Pa.3. The nasal airway resistance of the patients with nasal septem deviation group is larger than the heathy people group, the former is 0.44±0.18kpa/L/s, the latter is 0.16±0.03kpa/L/s , they have statistics mean P<0.05.Conclusion:1. The three-dimensional of the nasal airway can refect the characteristic of the human nasal airway ,it can be used to analysis the change of the aerodynamic in nasalcavity which caused by the abnormal anatomy of the nose.2. The nose adapts to the abnormal aerodynamic caused by the deviation of the nasal septem,the turbinate bone in the broad nasal cavity increases ,it can build a foundation for the construction of the model of self-adaptation to human nasal construction through this experiment .3. For the patient who gets nasal obstruction caused by the nasal septem deviation and the turbinate bone gets increasing in the opposite side, the basic therapy is to correct the deviated nasal septem, correct the abnormal nasal structure .4. The quantity of airflow in the narrow side nasal cavity of the patients with nasal septem deviation is vary small, it can't cause olfactory sensation which leading to the decrease of olfactory sensation, hinting that there are some relationships between the decrease of olfactory sensation and the aerodynamic in nasal cavity .5. In the experimental group, the area of the nasal airway is very small and the nasal airway resistance increases ,the sustained increase of the nasal airway resistance can do bad to the function of respiration of human ,it can also lead to OSAS .6. This experiment can proof that human nose has the function of self-adaptation .