| Objective:The three-dimensional finite element model of upper airway filling in supine position and maximum elevation position was reconstructed with two-dimensional image of MRI.Measuring anatomical data.Anatomical specificity of upper airway filling model for difficult airways and normal airways.To explore its role and significance in difficult airway assessment.Methods:Forty three-dimensional finite element models of upper airway,20 patients with normal airway and 20 patients with difficult airway were selected.Normal airway group was divided into group A and diffieult airway group was divided into group B.Two-dimensional image data of 40 head and neck three-dimensional finite element models were obtained.The data were input into Mimics 10.01 software to reconstruct the three-dimensional finite element model of upper airway.Select 3D Objects with Modules in Software.Click on the properties to get the volume data.The airway volume Vl3 V2 in the supine position and the maximum elevation position of group A5 and the airway volume V1’ and V2Z in the supine position and the maximum elevation position of group B.Introduce 3D models of A and B into 3-Matic software.The two-dimensional projection surface is made into 1 mm2 meshes per grid by using MATLAB image processing programming software,and the relevant anatomical data on the two-dimensional projection surface are measured by using Image J software.The two points at the widest point are a and b,and the highest two points are e and d.The diameters of the ab and cd are measured,the area of the abed four points is Sabcd,the angles of the two lines of ad and cd are ∠adb and the angles of the two lines of ac and ad are ∠ cad.The distance,angle and area data-of the two groups were compared,and the anatomical differences between the two groups were analyzed.Results:1.Comparing the volume of the three-dimensional airway model in the two groups,whether in the supine position or the maximum position,the normal airway group was signifieantly larger than the difficult airway group(P<0.01);in the supine position to the maximum When the position of the extension was changed,the volume of the airway model in the normal airway group and the difficult airway group increased(P>0.05),and the airway volume on the normal airway group changed more.2.Two-dimensional projection of the upper three-dimensional airway model was carried out,and the data were measured in the coronal,sagittal and horizontal positions.The results are as follows:①When the coronal position changes from the supine position to the maximum elevation position,there was no significant difference in the change rate of ab value of the longest diameter line between the two groups(P>0.05).There was no significant difference in the change rate of the cd value of the widest line of the two groups(P>0.05).a,b,c,d four points constitute the maximum surface area Sabcd value change rate comparison,the difference was not statistically significant(P>0.05);two groups of ad,cd radial line composition ∠ adb value change rate comparison,the difference was not statistically significant(P>0.05).②When the sagittal position changes from the supine position to the maximum elevation position,there was a significant difference in the change rate of ab value of the longest diameter line between the two groups(P<0.01).There was no significant difference in the change rate of the cd value of the widest diameter line between the two groups(P>0.05).a,b,c,d four points constitute the maximum surface area Sabcd value change rate comparison,the difference is extremely significant(P<0.01);two groups of ad,bd line composition ∠adb value change rate comparison,the difference is statistically significant(P<0.05),There was no significant difference in the change rate of ∠cad between the two groups(P>0.05).③ When the horizontal position changes from the supine position to the maximum elevation position,there was no significant difference in the change rate of ab value of the longest diameter line between the two groups(P>0.05).There was no significant difference in the change rate of the cd value of the widest line of the two groups(P>0.05).a b,c,d four points constitute the maximum surface area Sabcd value change rate comparison,the difference was not statistically significant(P>0.05);two groups of ad,cd radial line composition ∠adb value change rate comparison,the difference was not statistically significant(P>0.05).Conclusions:Three-dimensional finite element model of upper airway filling based on two-dimensional image reconstruction of MRI can effectively reflect the volume of upper airway,the longest sagittal diameter length,area and angle of upper airway,and can accurately reflect the anatomical differences between difficult airway patients and normal airway patients.The data measured in this study can truly reflect the anatomical differences between normal airway group and difficult airway group,and can be used for future clinical research and evaluation of difficult airway. |
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