CN115270566B - Auxiliary assessment method and device for damaged mandible - Google Patents
Auxiliary assessment method and device for damaged mandibleInfo
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Abstract
The invention discloses an auxiliary evaluation method and device for a damaged mandible, which comprises an image acquisition module, a mandible fracture model construction module, a numerical analysis model construction module, a mathematical model construction module, an evaluation module and an evaluation module, wherein the image acquisition module is used for acquiring CT images of the damaged mandible, the mandible fracture model construction module is used for constructing a mandible fracture model according to the CT images, the numerical analysis model construction module is used for constructing a numerical analysis model according to the mandible fracture model, the mathematical model construction module of the damaged mandible is used for constructing a mathematical model of a fixed position and angle of a titanium plate after mandible fracture repair according to the numerical analysis model, and the evaluation module is used for evaluating mandible fracture repair quality according to the mathematical model. The invention can quickly realize the model construction of the damaged mandible fracture, the evaluation model after construction is accurate in evaluation, the obtained titanium plate is installed at the mandible in a reasonable and reliable position and angle, the stress concentration is avoided, and the secondary human body damage caused after the installation is avoided.
Description
Technical Field
The invention belongs to the technical field of damaged mandible fracture model evaluation, and relates to an auxiliary evaluation method and device for damaged mandible.
Background
With the improvement of health consciousness, medical engineering is continuously in depth, and the surgical treatment scheme is promoted to develop towards high efficiency and high precision. The mandible is the only movable skeleton in the face skeleton, is positioned at the lower part of the face, is also the skeleton with the largest face area of a human body, is easy to fracture in various sudden accidents, accounts for 23% -42% of the face fracture, influences physiological functions of chewing, biting and the like of a patient, and causes psychological burden to the patient due to facial defects, so that the life quality of the patient is reduced.
The treatment of mandible fracture includes conservative treatment and open operation treatment, the conservative treatment avoids the trauma caused by operation, but traction equipment is required to be installed on the face of a patient, the treatment method has long recovery time and limited daily life of the patient, and the other is a strong internal fixation technology for fixing the fracture position by adopting a titanium plate. The fracture is exposed through the operation, the titanium plate is fixed at the fracture, the treatment cycle is short, the success rate is high, but the fixation of the titanium plate is usually according to the clinical experience of doctors, the theoretical guidance is lacking, meanwhile, the metal mechanical property of the titanium plate is greatly different from that of bone tissue, the stress concentration is easy to generate, the stress conflict between the titanium plate and the bone can occur after the titanium plate is fixed, the titanium plate is loosened and even broken, the secondary operation is caused, and the pain and the treatment time of patients are increased.
Disclosure of Invention
The invention aims to solve the technical problem of providing an auxiliary evaluation method and device for damaged mandible so as to solve the technical problem in the prior art.
The technical scheme adopted by the invention is that the auxiliary evaluation method of the damaged mandible comprises the following steps:
s1, acquiring CT images related to damaged mandible;
S2, according to the CT image of the damaged mandible obtained in the step S1, utilizing a Mimics medical image processing platform to build an initial model of the mandible, utilizing a reverse engineering processing platform to conduct surface optimization on the initial model, simulating a mandible fracture model in three-dimensional design software by the optimized initial model, and completing assembly of a titanium plate and the mandible;
S3, constructing a mandible numerical analysis model, namely introducing the assembled mandible fracture model of the titanium plate and the mandible obtained in the S2 into a simulation computing platform Abaqus for simulation analysis, and completing the construction of the mandible numerical analysis model;
S4, constructing a mathematical model of the damaged mandible, namely constructing a mathematical model of the fixed position and angle of the titanium plate after the mandible fracture repair according to the data of the numerical analysis model obtained in the S3;
and S5, evaluating the repair quality according to the mathematical model.
In S1, a medical image CT device is adopted to collect CT images related to mandible, the size is 604 multiplied by 640 gray scale images, and the thickness of the layer is 0.25mm.
When the medical image CT equipment scans, the cervical vertebra is scanned until reaching the upper eye orbit, and then the image is saved as a DICOM format.
The specific method in S2 is that CT images are imported into a Mimics medical image processing platform, after the horizontal plane, the coronal plane and the sagittal plane are checked to be free of errors, corresponding masks are generated according to preset bone threshold values of software, facial bones are extracted, then the parts which are not connected with mandibles are removed by utilizing regional growth, then the rest parts which are connected with mandibles are erased by utilizing a mask editing tool, finally an initial three-dimensional model is generated, the number of triangular faces of the initial model is huge, the defects of flash, burrs, breakage and the like are also existed on the surface of the model, the initial three-dimensional model is imported into a reverse engineering processing platform Geomagic, the polygonal processing stage is entered, the triangular faces with nails and redundancy are deleted, the surfaces of the model are processed smoothly, locally ground and repairing cavities are processed, the quality of triangular grids meets the requirement of constructing curved faces, after the triangular faces are repaired, the model is divided into curved faces, the curved faces are required to be divided into blocks, the initial three-dimensional model is rectangular, the corresponding characteristic boundaries are arranged on the surface model, the curved faces are designed into curved faces, the three-dimensional curved faces are successfully matched with the curved faces, the three-dimensional curved faces are designed according to the three-dimensional model, the three-dimensional curve face structure is successfully, the three-dimensional curve face structure is designed, the three-dimensional curve face structure is formed, the curve face structure is successfully is formed, and the curve face surface structure is formed, and the curve face model is successfully is reduced, and the curve surface structure is formed by the curve surface plane is formed by the three-plane, and simulating various fractures, namely additionally installing a titanium plate on the model, and simulating the fractures of the titanium plate and the model.
The specific method in S3 is that a three-dimensional model format is led out in an X_T format in a three-dimensional design software platform, the X_T format is led into an emulation calculation platform Abaqus, three material properties of titanium alloy, cortical bone and cancellous bone are established, flexible springs are used for replacing muscles which are necessary when the mandible of the masseter muscle, temporal muscle, external pterygoid muscle and internal pterygoid muscle moves, and the size of a network is determined by sequentially reducing the grid size and increasing the grid density.
The specific method in S4 is that fracture is defined as a fracture line, the fracture line is taken as a 0-degree line, anticlockwise is taken as a positive angle, grid, load and boundary conditions are controlled to be consistent, only the fixed angle of a titanium plate is changed, simulation experiments are conducted every 5 degrees, mandibular stress, displacement and titanium plate stress are collected, mathematical models of the fixed angle, the mandibular stress, the displacement and the titanium plate stress and the displacement are obtained according to a principle that the determination coefficient is closer to 1 and the root mean square is closer to 0 and a function scatter diagram, a perpendicular bisector of a wound is taken as a zero line, the direction from the zero line to a molar area is defined as a positive direction, the direction from the zero line to the mandibular bottom is defined as a negative direction, the grid, the load and the boundary conditions are controlled to be consistent, only the fixed position of the plate is changed, the simulation experiments are conducted every 1mm from-9 mm to 9 mm, the mandibular stress, the displacement of the titanium plate stress are collected, the titanium plate displacement are conducted, and the mathematical models of the titanium plate fixed angle position, the mandibular stress and the titanium plate displacement are obtained according to the principle that the determination coefficient is closer to 1 and the root mean square is closer to 0 and the function scatter diagram is obtained.
The change rule of the mandible stress y 1 along with the change of the titanium plate fixed angle x is obtained:
Wherein k 0、ai、bi、ki and g i are coefficient values obtained by fitting the angle of figure 10 with a jawbone stress simulation experiment scattered point data graph, x represents a fixed angle of the titanium plate, and y 1 represents mandible stress corresponding to a certain fixed angle x;
along with the change of the fixed angle x of the titanium plate, the change rule of the mandible displacement y 2 is as follows:
Wherein a i′,bi′,ki 'and gamma i' are coefficient values obtained by fitting the angle of fig. 11 with a jawbone displacement simulation experiment scattered data graph, x represents a fixed angle of the titanium plate, y 2 represents mandible displacement corresponding to a certain fixed angle x, and i=1-4;
along with the change of the fixed angle x of the titanium plate, the change rule of the stress y 3 of the titanium plate is as follows:
Wherein k 0″,ai″,bi″,ki 'and gamma i' are coefficient values obtained by fitting the angle of figure 12 with a titanium plate stress simulation experiment scattered point data graph, x represents a fixed angle of the titanium plate, y 3 represents a titanium plate stress value corresponding to a certain fixed angle x, and i=1-4;
Along with the change of the titanium plate fixed angle x, the change rule of the titanium plate displacement y 4:
Wherein a i″′,bi″′,ki '' is a coefficient value obtained by fitting a 13-angle and a titanium plate displacement simulation experiment data graph, x represents a fixed angle of the titanium plate, y 4 represents titanium plate displacement corresponding to a certain fixed angle x, and i=1-2.
Along with the change of the titanium plate fixing position x 1, the change rule of the mandible stress y 5:
Wherein: And For the coefficient value obtained by fitting the distance of fig. 15 to the jawbone stress simulation experiment scattered point data graph, x 1 represents the fixed position of the titanium plate, and y 5 represents the mandible stress corresponding to a certain fixed position x 1;
along with the change of the titanium plate fixing position x 1, the change rule of the mandible displacement y 6:
Wherein: And For the coefficient value obtained by fitting the distance of fig. 16 to the jawbone displacement simulation experiment scattered point data map, i=1-2, x 1 represents the fixed position of the titanium plate, and y 7 represents the mandible displacement corresponding to a certain fixed position 1;
Along with the change of the titanium plate fixing position x 1, the change rule of the titanium plate stress y 8:
Wherein: And For the coefficient value obtained by fitting the distance of fig. 17 and the titanium plate stress simulation experiment scattered point data graph, x 1 represents the fixed position of the titanium plate, y 7 represents the titanium plate stress corresponding to a certain fixed position x 1, and along with the change of the titanium plate fixed position x 1, the change rule of the titanium plate displacement y:
Wherein: And For the coefficient value obtained by fitting the distance of FIG. 17 to the titanium plate stress simulation test scatter plot, x 1 represents the fixed position of the titanium plate, and y 8 represents the titanium plate displacement corresponding to a certain fixed position x 1.
An auxiliary evaluation device for damaged mandible comprises,
The image acquisition module is used for acquiring CT images of damaged mandibles;
The mandible fracture model construction module is used for constructing a three-dimensional mandible fracture model of the titanium plate and mandible repair according to the CT image;
the numerical analysis model construction module is used for constructing a numerical analysis model by utilizing a simulation calculation platform according to the mandible fracture model;
The mathematical model construction module of the damaged mandible constructs a mathematical model of the fixed position and angle of the titanium plate after the mandible fracture repair according to the data of the numerical analysis model;
and the evaluation module is used for performing the evaluation of the mandible fracture repair quality through the color partition according to the corresponding functional relation of the mathematical model, and correspondingly using the functional relation as the relation between the color partition and the corresponding titanium plate fixed position and angle.
Compared with the prior art, the invention has the following advantages:
1) The evaluation method can quickly realize the model construction of the damaged mandible fracture, the evaluation model after construction is accurate in evaluation, the obtained titanium plate is mounted at the mandible in a reasonable and reliable position and angle, stress concentration is avoided, and secondary human body damage caused after mounting is avoided;
2) The CT machine can rapidly obtain CT images of damaged mandibles, a damaged mandible three-dimensional model is constructed according to the three-dimensional reconstruction function of the CT images, an initial model is obtained, the three-dimensional model constructed by utilizing a medical image processing platform is rough based on CT data, defects such as miscellaneous points, burrs and the like are present on the surface, the surface optimization, curved surface combination and the like are carried out by utilizing a Mimics medical image processing platform, the traditional implant or orthosis is difficult to be completely attached due to the difference of the size and the characteristics of each part of the body of each patient, the protection and the rehabilitation assistance function in the use are not ideal, a corresponding model can be easily constructed in the Mimics medical image processing platform of a reverse engineering processing platform, the implant which is completely attached is designed, and the individuation and the precision level of the implant are greatly improved. After the mandibular bone lesion is resected, the design of the personalized mandibular bone cutting guide plate can be completed, and the accurate repair of the defects of the mandible can be ensured;
3) And analyzing the repaired three-dimensional model by a finite element analysis technology to obtain a mathematical module for simulating the stress and distribution and displacement change of the mandible when the mandible bears external force, and evaluating the repaired three-dimensional model according to the change, wherein the evaluation is reasonable and reliable.
Drawings
FIG. 1 is a schematic diagram of a flow implementation of the present invention;
FIG. 2 is an initial three-dimensional model of the mandible;
FIG. 3 is a graph of the presence of defects on the surface of an initial three-dimensional model;
FIG. 4 is a view of an initial three-dimensional model trim model patch;
FIG. 5 is a surface fitting map of an initial three-dimensional model;
FIG. 6 is a diagram of cortical and cancellous bone constructed with an initial three-dimensional model;
FIG. 7 is an assembly view of an initial three-dimensional model mandible with titanium plate;
FIG. 8 is a determination of the mandibular boundary conditions of an initial three-dimensional model;
FIG. 9 is a stress and displacement cloud of the 25℃mandible and titanium plate, wherein (a) the 25℃mandible stress cloud, (b) the 25℃mandible displacement cloud, (c) the 25℃titanium plate stress cloud, and (d) the 25℃titanium plate displacement cloud;
FIG. 10 is a graph of angle versus jaw stress;
FIG. 11 is a graph of angle versus jaw displacement;
FIG. 12 is a graph of angle versus titanium plate stress;
FIG. 13 is a graph of angle versus titanium plate displacement;
FIG. 14 is a stress and displacement cloud of mandible and titanium plate at zero line, wherein (a) the mandible stress cloud at zero line, (b) the mandible displacement cloud at zero line, (c) the titanium plate stress cloud at zero line, (d) the titanium plate displacement cloud at zero line;
FIG. 15 is a graph of distance versus jaw stress;
FIG. 16 is a graph of distance versus jaw displacement;
FIG. 17 is a graph of distance versus titanium plate stress;
FIG. 18 is a graph of distance versus titanium plate displacement;
FIG. 19 is an example diagram showing (a) a top view titanium plate position in CT, (b) a side view titanium plate position in CT, (c) a three-dimensional model titanium plate position, and (d) measuring titanium plate position.
Detailed Description
The invention will be further described with reference to specific examples.
Embodiment 1. An auxiliary evaluation method of damaged mandible, the flow is shown in figure 1, CT image of mandible is acquired by medical equipment, initial three-dimensional model of mandible is constructed by medical modeling platform, model surface is optimized by reverse engineering processing platform, and the optimized model is assembled with mandible by fracture model and titanium plate in three-dimensional design platform. Aiming at the easily-occurring mandibular angle fracture, biomechanical characteristics of the mandible are known through simulation analysis, data are collected, mathematical models between the titanium plate, the mandible and the stress and displacement of the titanium plate at different fixing positions and different fixing angles are explored, whether the fixing positions and angles of the titanium plate are suitable for qualitative division or not is judged, and after a user slides to select the fixing positions and angles of the titanium plate, the repairing tool can display different colors.
And 1, acquiring a CT image related to the mandible by using professional medical equipment. A grayscale image of size 604 x 640 was acquired with a layer thickness of 0.25mm. A specialized medical device is used to acquire CT images of mandible correlations. A gray scale image of 640 x 640, with a layer thickness of 0.25mm. In particular, in order to ensure the integrity of the mandible, the CT machine scans from the cervical vertebra to the upper orbit, and then saves the image in DICOM format for transmission between different devices.
And 2, constructing a three-dimensional model of the mandible by adopting a multi-platform cooperation method. And (3) establishing an initial model of the mandible by utilizing the CT image containing the mandible obtained in the step (1) and utilizing a Mics medical image processing platform, carrying out surface optimization on the initial model by utilizing a reverse engineering processing platform Geomagic, simulating mandible fracture in conventional three-dimensional design software SolidWorks, and completing assembly of the titanium plate and the mandible. After CT images are imported into a Mimics medical image processing platform and no errors are detected on the horizontal plane, the coronal plane and the sagittal plane, corresponding masks are generated according to a bone threshold [226,3071] preset by software, the whole facial skeleton is extracted because the threshold of the mandible is the same as the whole facial tissue, then the part which is not connected with the mandible is removed by using region growth, the condyle part of the mandible is connected with the maxilla, the rest part connected with the mandible is erased by using a mask editing tool, and finally an initial three-dimensional model is generated, as shown in figure 2. The initial model established by utilizing the Mimics is stored as an STL format, the STL format is a shell model formed by triangular surfaces, the number of the triangular surfaces is huge, the surface of the model also has the defects of flash, burrs, breakage and the like, as shown in figure 3, the model is led into a reverse engineering processing platform Geomagic, the model enters a polygonal processing stage, the triangular surface is optimally processed at the stage, nails are deleted, the redundant triangular surfaces are processed on the surface of the model in a smooth, local skin grinding, cavity repairing and the like manner, the influence on the appearance of the model is extremely small, and the quality of the triangular grid can meet the requirement of constructing curved surface sheets. After the triangular patch is repaired, the curved surface mesh is divided, the model is divided into blocks, and corresponding feature boundaries are arranged on the model according to the structural features of the model and the requirement that the curved surface fitting is preferably rectangular. After the feature boundary is constructed, the curved surface of the constructed model is divided into a plurality of parts, the model constructs curved surface sheets according to the constructed feature boundary, but at the moment, the curved surface sheets have smaller curved surface sheet angles and height angular points, the curved surface cannot be constructed successfully, and a more regular curved surface sheet structure is finally achieved by moving and adding the curved surface sheets in the constructed feature boundary, as shown in fig. 4, and finally, the fitted curved surfaces are combined, the number of the curved surfaces is reduced, and the curved surface sheets are converted into a common three-dimensional model format, as shown in fig. 5. Cancellous bone is then constructed by offsetting and performing boolean operations in a three-dimensional design software platform SolidWorks to construct cortical bone, which is fused together by the insertion of the parts, as shown in fig. 6. The method is characterized in that various fractures are modeled, titanium nail holes are designed on the mandible, the design and assembly of a titanium plate are completed, as shown in fig. 7, basic work is done for the construction of a subsequent numerical analysis model, and meanwhile, image expression is provided for the establishment of an operation scheme.
And 3, constructing a numerical analysis model of the mandible. And (3) introducing the model obtained in the step (2) into a simulation computing platform Abaqus, setting materials and boundary conditions of the mandible, and performing simulation analysis to complete the construction of the mandible numerical analysis model. In the three-dimensional design platform, the assembly is led out in an X_T format, in the simulation calculation platform Abaqus, the assembly is led in by a method of leading in components, three material properties of titanium alloy, cortical bone and cancellous bone are established, wherein the elastic modulus of the titanium alloy is 120000, the elastic modulus of the cortical bone is 13700, the elastic modulus of the cancellous bone is 1370, the Poisson ratio is 0.3, and the material properties are given to the corresponding components. The loading mode of the load is concentrated stress and simulates single-point occlusion. The titanium nails and the titanium nail holes on the mandible are set as binding restraints, friction restraint is adopted at fracture wound positions, flexible springs are used for replacing muscles which are necessary for the movement of the mandible such as the bite muscle, the temporal muscle, the external pterygoid muscle, the internal pterygoid muscle and the like, the condylar prominences are rigidly fixed, and as shown in fig. 8, the size of the network is determined by sequentially reducing the mesh size and increasing the mesh density.
And 4, constructing a mathematical model of the damaged mandible. And (3) according to the operation of the step (3), collecting data through experiments, searching for a relation between the data, and constructing a mathematical model of the fixed position and angle of the titanium plate after the mandible fracture is repaired. The fracture is defined as a fracture line, the fracture line is taken as a 0-degree line, the anticlockwise direction is taken as a positive angle, the variables such as a control grid, load and boundary conditions are consistent, the fixed angle of the titanium plate is only changed, simulation experiments are carried out at intervals of 5 degrees from 25 degrees to 155 degrees, and as shown in fig. 9, the mandible stress and displacement are collected by a stress displacement graph when 25 degrees are the stress and displacement of the titanium plate. According to the principle that the closer the determination coefficient is to 1, the root mean square is to 0, and the scatter diagram of the function is shown in fig. 10-13, the titanium plate fixing angle and the mandible stress are obtained, the titanium plate fixing angle and the mandible displacement are shown in formula 1, the titanium plate fixing angle and the titanium plate stress are shown in formula 2, the titanium plate fixing angle and the titanium plate displacement are shown in formula 3, and the titanium plate fixing angle and the titanium plate displacement are shown in formula 4.
The center vertical line of the wound is used as a zero line, the zero line is defined as a positive direction towards the molar region, and the zero line is defined as a negative direction towards the mandibular bottom. The control grid, load and boundary conditions are consistent, only the fixed position of the titanium plate is changed, simulation experiments are carried out every 1mm from-9 to 9, as shown in fig. 14, the stress and displacement cloud pictures of the mandible and the titanium plate at the zero line are obtained, and the mandible stress and displacement and the titanium plate stress and displacement are collected. According to the principle that the closer the determination coefficient is to 1, the root mean square is to 0, and the scatter diagram of the function is shown in fig. 15-18, the titanium plate fixing position and the mandible stress are obtained, the titanium plate fixing position and the mandible displacement are shown in formula 5, the titanium plate fixing position and the titanium plate stress are shown in formula 6, the titanium plate fixing position and the titanium plate displacement are shown in formula 7, and the titanium plate fixing position and the titanium plate displacement are shown in formula 8.
y5＝6.74-0.5221cos(0.3506x1)-0.0391sin(0.3506x1)+0.6213cos(0.7012x1)+0.0715sin(0.7012x1)-0.0444cos(1.0518x1)+0.1226sin(1.0518x1)+0.113cos(1.4024x1)-0.0927sin(1.4024x1)-0.2037cos(2.1036x1)-0.1737sin(2.4542x1)+0.0984cos(2.8048x1) (5)
y7＝2.268-0.0367cos(0.3221x1)-0.01sin(0.3221x1)-0.02414sin(0.6442x1)+0.03399cos(0.9663x1)-0.03031sin(0.9663x1)+0.04406cos(1.2884x1)+0.0435sin(1.2884x1)-0.01213cos(1.6105x1)+0.0086sin(1.6105x1)+0.043cos(1.9326x1)+0.0432sin(1.933x1)-0.02058cos(2.2547x1)-0.0163sin(2.255x1)+0.0075cos(2.5768x1)-0.2322sin(2.5768x1) (7)
y8＝1.632-0.0265cos(0.2735x1)+0.0124sin(0.2735x1)+0.0047cos(0.547x1)-0.019sin(0.547x1)+0.0112sin(0.8205x1)+0.00613cos(1.094x1)-0.0075sin(1.094x1)+0.0079sin(1.3675x1) (8)
And 5, evaluating the mandible repair model according to the mathematical model obtained in the step 4, namely designing a mandible auxiliary repair evaluation module based on MATLAB according to the mathematical model obtained in the step 4, namely, whether the fixed position and angle of the titanium plate are suitable for qualitative division or not, and displaying different colors by a repair tool after the user slides and selects the fixed position and angle of the titanium plate, so that the actual operation is convenient. The specific operation is that a user interface of the ' mandible repair auxiliary tool ' is designed, the user interface comprises two buttons of a ' position where a titanium plate is fixed ' and a ' angle where the titanium plate is fixed ', a menu bar comprises a ' file ', ' exit ', ' about a ' tab ', and the ' file ' has a function of jumping to any sub-interface. Clicking the titanium plate fixed angle of the main interface or the titanium plate fixed angle under the file option card, the interface enters the menu bar of the titanium plate fixed angle sub-interface, wherein the menu bar of the interface has jaw stress, jaw displacement, titanium plate stress and titanium plate displacement, the interface is switched by clicking the corresponding option card, and the main interface button is returned by clicking the exit. The main controls include a slider, an editable numerical box, a dashboard, and a static text box. The slider is for user interaction, and the user slides the slider to select a numerical value, and the numerical value is displayed in an editable numerical value frame above the slider. Meanwhile, when the sliding block is slid, the pointer of the instrument panel can correspondingly rotate, when the pointer is stopped in a red area, the fixed angle of the titanium plate is indicated to be unsuitable, when the pointer is stopped in a yellow area, the fixed angle of the titanium plate is indicated to be acceptable, and when the pointer is stopped in a green area, the fixed angle of the titanium plate is indicated to be suitable. This tertiary design is necessary because the physician can choose between the yellow and green areas based on clinical experience, enhancing flexibility, as a result of individual differences in the mandible and fracture conditions.
Clicking the titanium plate fixed position of the main interface or the titanium plate fixed position under the file option card, the interface enters the titanium plate fixed position sub-interface, the layout design of a main menu and a control of the interface is similar to that of the titanium plate fixed angle sub-interface, the numerical value is selected through the sliding slide block, and the pointer points to different areas. When the pointer stays in the red area, the position of the titanium plate is not suitable, when the pointer stays in the yellow area, the position of the titanium plate is acceptable, and when the pointer stays in the green area, the position of the titanium plate is suitable. After clicking the exit button, a prompt box appears, the default operation is not exit, misoperation of a user is avoided, the operation is not continued to exit the switchable interface, and the doctor is assisted in determining the fixed position of the titanium plate by using the two sub-interfaces of the fixed angle of the titanium plate and the fixed position of the titanium plate.
However, the analysis and calculation involves the operation of a plurality of processing platforms, and a certain background knowledge of the industry is required, so that the learning period of the relevant background knowledge is long for the application object doctor to learn again, and the burden of the doctor is increased. For doctors without engineering background, performing data analysis after performing multiple simulation experiments is not an optimal method, and is time-consuming and labor-consuming, and inconvenient to apply to practice. Therefore, the mandible auxiliary repair tool is researched, a concise user interface is designed, and a doctor can use the mandible auxiliary repair tool in clinic conveniently.
Example 2 an auxiliary evaluation device for a damaged mandible, comprising,
The image acquisition module is used for acquiring CT images of damaged mandibles;
The mandible fracture model construction module is used for constructing a three-dimensional mandible fracture model of the titanium plate and mandible repair according to the CT image;
the numerical analysis model construction module is used for constructing a numerical analysis model by utilizing a simulation calculation platform according to the mandible fracture model;
The mathematical model construction module of the damaged mandible constructs a mathematical model of the fixed position and angle of the titanium plate after the mandible fracture repair according to the data of the numerical analysis model;
and the evaluation module is used for performing the evaluation of the mandible fracture repair quality through the color partition according to the corresponding functional relation of the mathematical model, and correspondingly using the functional relation as the relation between the color partition and the corresponding titanium plate fixed position and angle.
The implementation method of each module is implemented by adopting the corresponding method in the embodiment 1. The model construction of the damaged mandible fracture can be rapidly realized through the evaluation device, the evaluation model after construction is accurate in evaluation, the obtained titanium plate is installed at the mandible in a reasonable and reliable position and angle, stress concentration is avoided, and secondary human body damage caused after installation is avoided.
The effect of the model was that some mandibular angle fracture case (fig. 19) was surgically fixed by the doctor using titanium plates. And comparing the acquired CT data after operation with the model calculation result. In order to facilitate measurement of the fixing position of the titanium plate, a three-dimensional model is built in the ceramics, as shown in fig. 19 (c), the fixing position of the titanium plate is marked according to the measurement, as shown in fig. 19 (d), the size of the drawing is about 6.09 times of the size of a real jaw bone, the distance center line of the titanium plate is 35.88/6.09=5.89 mm, a mathematical model is built according to the invention to calculate, the stress value of the titanium plate arranged at the position is lower than 1/3 of the maximum stress, the feasible arrangement area is judged according to the mathematical model, and the calculation result is consistent with the experience judgment of doctors. The included angle between the fracture line and the titanium plate is 88.61 degrees, the stress arranged at the angle is also smaller than 1/3 of the maximum stress according to model calculation, the feasible arrangement area is judged according to the mathematical model, and the calculation result is consistent with the experience judgment of doctors, so that the constructed mathematical model is proved to be suitable for assisting doctors in developing operation planning.
The foregoing is merely illustrative of the present invention, and the scope of the present invention is not limited thereto, and any person skilled in the art can easily think about variations or substitutions within the scope of the present invention, and therefore, the scope of the present invention shall be defined by the scope of the appended claims.
Claims (8)
1. A method for assisting in assessing a damaged mandible is characterized in that the method comprises the following steps:
s1, acquiring CT images related to damaged mandible;
S2, according to the CT image of the damaged mandible obtained in the step S1, utilizing a Mimics medical image processing platform to build an initial model of the mandible, utilizing a reverse engineering processing platform to conduct surface optimization on the initial model, simulating a mandible fracture model in three-dimensional design software by the optimized initial model, and completing assembly of a titanium plate and the mandible;
S3, constructing a mandible numerical analysis model, namely introducing the assembled mandible fracture model of the titanium plate and the mandible obtained in the S2 into a simulation computing platform Abaqus for simulation analysis, and completing the construction of the mandible numerical analysis model;
S4, constructing a mathematical model of the damaged mandible, namely constructing a mathematical model of the fixed position and angle of the titanium plate after the mandible fracture repair according to the data of the numerical analysis model obtained in the S3;
s5, evaluating the repair quality according to a mathematical model;
the specific method in S4 is that fracture is defined as a fracture line, the fracture line is taken as a 0-degree line, anticlockwise is taken as a positive angle, grid, load and boundary conditions are controlled to be consistent, only the fixed angle of a titanium plate is changed, simulation experiments are conducted every 5 degrees, mandibular stress, displacement and titanium plate stress are collected, mathematical models of the fixed angle, mandibular stress, displacement and titanium plate stress and displacement are obtained according to a principle that the determination coefficient is closer to 1 and the root mean square is closer to 0 and a function scatter diagram, a perpendicular bisector of a wound is taken as a zero line, the direction from the zero line to the molar region is defined as a positive direction, the direction from the zero line to the mandibular bottom is defined as a negative direction, the grid, load and boundary conditions are controlled to be consistent, only the fixed position of the plate is changed, simulation experiments are conducted every 1mm from-9 mm to 9 mm, the mandibular stress, the displacement of the titanium plate stress and the titanium plate displacement are collected, and the mathematical models of the fixed angle position, the mandibular stress, the displacement and the titanium plate stress and the titanium plate displacement are obtained according to the principle that the determination coefficient is closer to 1 and the root mean square is closer to 0 and the function scatter diagram.
2. The method for assisted assessment of a damaged mandible according to claim 1, wherein the CT image of the mandible is acquired by a medical image CT apparatus in S1, with a gray scale image of 604X 640 and a layer thickness of 0.25mm.
3. The method of assisted assessment of a damaged mandible as claimed in claim 1, wherein the medical image CT apparatus scans from cervical vertebrae to the upper orbit before saving the image in DICOM format.
4. A method for assisting in evaluating damaged mandible according to any one of claims 1-3, characterized by comprising the specific steps of S2, introducing CT image into a micro medical image processing platform, checking whether the horizontal plane, the coronal plane and the sagittal plane are wrong, generating corresponding masks according to a bone threshold preset by software, extracting facial bones, removing the unconnected parts of the mandible by utilizing regional growth, erasing the rest connected parts of the mandible by utilizing a mask editing tool, finally generating an initial three-dimensional model, introducing the initial three-dimensional model into a reverse engineering processing platform Geomagic, entering a polygonal processing stage, optimizing triangular patches, deleting nails and redundant triangular faces, smoothing, locally polishing the surfaces of the model, repairing cavities, enabling the triangular mesh quality to meet the requirements of constructing the curved patches, dividing the curved surface mesh after the triangular patch is repaired, carrying out block division on the model, fitting the structural characteristics of the model and the curved surface into rectangular curved surface, arranging the corresponding characteristic boundary of the curved surface patches on the curved surface patches, carrying out three-dimensional operation on the three-dimensional model, constructing the three-dimensional model by combining the three-dimensional model with the three-dimensional model, constructing the three-dimensional model after the three-dimensional model and the three-dimensional model, and carrying out three-dimensional operation on the three-dimensional model, and (3) adding a titanium plate to the model to simulate the fracture of the titanium plate and the model.
5. The method for assisted assessment of a damaged mandible in accordance with claim 4, wherein:
The specific method in S3 is that a three-dimensional model format is led out in an X_T format in a three-dimensional design software platform, the X_T format is led into an emulation calculation platform Abaqus, three material properties of titanium alloy, cortical bone and cancellous bone are established, flexible springs are used for replacing muscles which are necessary when the mandible of the masseter muscle, temporal muscle, external pterygoid muscle and internal pterygoid muscle moves, and the size of a network is determined by sequentially reducing the grid size and increasing the grid density.
6. The method for assisted assessment of a damaged mandible as claimed in claim 1, wherein:
The change rule of the mandible stress y 1 along with the change of the titanium plate fixed angle x is obtained:
wherein k 0、ai、bi、ki and gamma i are coefficient values obtained by fitting, x represents a fixed angle of the titanium plate, and y 1 represents mandible stress corresponding to a certain fixed angle x;
along with the change of the fixed angle x of the titanium plate, the change rule of the mandible displacement y 2 is as follows:
Wherein a i′,bi′,ki 'and gamma i' are coefficient values obtained by fitting, x represents a fixed angle of the titanium plate, y 2 represents mandible displacement corresponding to a certain fixed angle x, and i=1-4;
along with the change of the fixed angle x of the titanium plate, the change rule of the stress y 3 of the titanium plate is as follows:
Wherein k 0″,ai″,bi″,ki 'and gamma i' are coefficient values obtained by fitting, x represents a fixed angle of the titanium plate, y 3 represents a stress value of the titanium plate corresponding to a certain fixed angle x, and i=1-4;
Along with the change of the titanium plate fixed angle x, the change rule of the titanium plate displacement y 4:
Wherein a i″′,bi″′,ki '' is a coefficient value obtained by fitting, x represents a fixed angle of the titanium plate, y 4 represents a titanium plate displacement corresponding to a certain fixed angle x, and i=1-2.
7. The method for assisted assessment of a damaged mandible as claimed in claim 1, wherein:
Along with the change of the titanium plate fixing position x 1, the change rule of the mandible stress y 5:
Wherein: And For fitting the obtained coefficient values, x 1 represents the fixed position of the titanium plate, and y 5 represents the mandible stress corresponding to a certain fixed position x 1;
along with the change of the titanium plate fixing position x 1, the change rule of the mandible displacement y 6:
Wherein: And For fitting the obtained coefficient values, i=1-2, x 1 represents the fixed position of the titanium plate, y 7 represents the mandible displacement corresponding to a certain fixed position 1;
Along with the change of the titanium plate fixing position x 1, the change rule of the titanium plate stress y 8:
Wherein: And For fitting the obtained coefficient value, x 1 represents the fixed position of the titanium plate, y 7 represents the titanium plate stress corresponding to a certain fixed position x 1, and along with the change of the fixed position x 1 of the titanium plate, the change rule of the displacement y of the titanium plate is as follows:
Wherein: And For fitting the obtained coefficient values, x 1 represents a fixed position of the titanium plate, and y 8 represents a displacement of the titanium plate corresponding to a certain fixed position x 1.
8. An auxiliary evaluation device for damaged mandible is characterized by comprising,
The image acquisition module is used for acquiring CT images of damaged mandibles;
The mandible fracture model construction module is used for constructing a three-dimensional mandible fracture model of the titanium plate and mandible repair according to the CT image;
the numerical analysis model construction module is used for constructing a numerical analysis model by utilizing a simulation calculation platform according to the mandible fracture model;
The mathematical model construction module of the damaged mandible constructs a mathematical model of the fixed position and angle of the titanium plate after the mandible fracture repair according to the data of the numerical analysis model;
Defining a fracture part as a fracture line, taking the fracture line as a 0-degree line, taking the anticlockwise direction as a positive angle, controlling the grid, the load and the boundary condition to be consistent, only changing the fixed angle of the titanium plate, performing simulation experiments every 5 degrees, and collecting the stress and the displacement of the mandible; obtaining a mathematical model of fixed angle and mandible stress, displacement and titanium plate stress and displacement according to the principle that the determination coefficient is closer to 1 and the root mean square is closer to 0 and the scatter diagram of the function, and obtaining a mathematical model of fixed angle and mandible stress, displacement and titanium plate stress and displacement according to the principle that the determination coefficient is closer to 1 and the root mean square is closer to 0 and the scatter diagram of the function, wherein the direction of the zero line towards the tooth grinding area is defined as positive direction, the direction of the zero line towards the mandible bottom is defined as negative direction, the control grid, the load and the boundary conditions are consistent, only the fixed position of the titanium plate is changed, simulation experiments are carried out at intervals of 1mm from-9 to 9, and the mandible stress, the displacement and the titanium plate stress and displacement are also collected;
and the evaluation module is used for performing the evaluation of the mandible fracture repair quality through the color partition according to the corresponding functional relation of the mathematical model, and correspondingly using the functional relation as the relation between the color partition and the corresponding titanium plate fixed position and angle.
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