Numerical simulation method and system for cement extrusion and dispersion under compression

Abstract

This invention belongs to the field of bone repair technology and provides a numerical simulation method and system for pressure-induced exudation and diffusion of bone cement. The method includes: acquiring relevant parameters of the bone-filled mesh bag and the fractured vertebral body; constructing numerical simulation models of the bone-filled mesh bag and the fractured vertebral body; based on the numerical simulation models and bone cement parameters, using porous media permeability mechanics and computational fluid dynamics respectively, calculating the equivalent permeability and its distribution in the bone-filled mesh bag and the fractured vertebral body, numerically simulating the spatial flow process of bone cement in the microenvironment of the bone-filled mesh bag and the fractured vertebral body, and predicting the diffusion distribution of bone cement; obtaining the spatial diffusion distribution morphology of bone cement in the actual fractured vertebral body microenvironment under the same numerical simulation conditions, and comparing it with the predicted bone cement diffusion distribution to optimize design variables, so that the optimized design variables can be used as the injection conditions for actual clinical surgery.

Description

Technical Field

[0001] This invention belongs to the field of bone repair technology, and in particular relates to a numerical simulation method and system for bone cement exudation and diffusion under pressure. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Bone cement is a bone repair material with self-curing properties used to fill the gap between bone and implants or the medullary cavity. The technique of using bone cement as a bone repair material to treat osteoporotic fractures is called bone repair technology. There are two common spinal bone repair techniques: percutaneous vertebroplasty (PVP) and percutaneous kyphoplasty (PKP). Current improvements to percutaneous vertebroplasty are largely based on the accumulation of experience from numerous clinical surgeries, such as vesselplasty. Vesselplasty mainly includes three processes: filling / injection of bone cement, diffusion, and curing. The diffusion process includes the pressure-induced seepage of bone cement from the porous medium of the bone-filled vesselplasty bag wall and the subsequent non-uniform diffusion within the microenvironment of the fractured vertebral body.

[0004] The inventors discovered that the diffusion distribution of bone cement injected into the fractured vertebral body in clinical practice is mostly determined by the experience of the attending physician, lacking theoretical guidance. These processes directly determine the clinical effectiveness and efficacy of bone cement, and also affect patients' satisfaction with the surgery. Summary of the Invention

[0005] To address the technical problems mentioned above, this invention provides a numerical simulation method and system for pressure-induced exudation and diffusion of bone cement. Based on the numerical simulation results and optimized design results of the pressure-induced exudation of bone cement from the micropores of the bone-filled mesh bag and the non-uniform diffusion process within the microenvironment of the fractured vertebral body, it can provide guidance on injection conditions for the bone cement injection process in actual clinical applications.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] The first aspect of the present invention provides a numerical simulation method for pressure effusion and diffusion of bone cement, comprising:

[0008] Obtain relevant parameters of the bone-filled mesh bag and the fractured vertebral body, and construct a numerical simulation model of the bone-filled mesh bag and the fractured vertebral body;

[0009] Based on the numerical simulation model and bone cement parameters, porous media permeation mechanics and computational fluid dynamics were used to calculate the equivalent permeability and distribution of the bone-filled mesh bag and the fractured vertebral body, respectively. The flow process of bone cement in the microenvironment of the bone-filled mesh bag and the fractured vertebral body was numerically simulated, and the diffusion distribution of bone cement was predicted.

[0010] The spatial diffusion distribution morphology of bone cement in the actual fracture vertebral microenvironment with the same numerical simulation conditions was obtained, and it was compared with the predicted bone cement diffusion distribution to optimize the design variables, so that the optimized design variables could be used as the injection conditions for actual clinical surgery.

[0011] The design variables include the injection pressure and viscosity of bone cement and the mesh diameter of the bone-filled mesh bag. The objective function for optimization is the dispersion distribution of bone cement.

[0012] A second aspect of the present invention provides a numerical simulation system for pressure leaching and diffusion of bone cement, comprising:

[0013] The numerical simulation model construction module is used to obtain relevant parameters of the bone-filled mesh bag and the fractured vertebral body, and to construct a numerical simulation model of the bone-filled mesh bag and the fractured vertebral body.

[0014] The diffusion distribution prediction module is used to calculate the equivalent permeability and distribution of the bone-filled mesh bag and the fractured vertebral body based on the numerical simulation model and bone cement parameters, using porous media permeation mechanics and computational fluid dynamics respectively. It numerically simulates the spatial flow process of bone cement in the microenvironment of the bone-filled mesh bag and the fractured vertebral body, and predicts the diffusion distribution of bone cement.

[0015] The design variable optimization module is used to obtain the spatial diffusion distribution pattern of bone cement in the real fracture vertebral microenvironment under the same numerical simulation conditions, and compare it with the predicted bone cement diffusion distribution to optimize the design variables, so that the optimized design variables can be used as the injection conditions for actual clinical surgery.

[0016] The design variables include the injection pressure and viscosity of bone cement and the mesh diameter of the bone-filled mesh bag. The objective function for optimization is the dispersion distribution of bone cement.

[0017] A third aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps in the numerical simulation method for compressive effusion and diffusion of bone cement as described above.

[0018] A fourth aspect of the present invention provides an electronic device including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps in the numerical simulation method for pressure effusion and diffusion of bone cement as described above.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] (1) The numerical simulation technology provided by this invention mathematically describes the process of bone cement seeping out of the mesh bag under pressure and then diffused non-uniformly in the microenvironment of the fractured vertebral body, which solves the problem of lack of systematic theoretical basis for the diffusion process after bone cement is injected into the fractured vertebral body by mesh bag molding technique.

[0021] (2) This invention innovatively integrates porous media permeation mechanics, computational fluid dynamics and bone cement bone repair theory, and numerically simulates the process of bone cement permeating under pressure from the bone filling mesh bag and dispersing non-uniformly in the microenvironment of the fractured vertebra.

[0022] (3) This invention provides a method that combines theoretical analysis, numerical simulation, experimental research and optimization design. It comprehensively applies sensitivity analysis, porous media flow mechanics, numerical simulation technology, virtual reality technology, medical imaging technology and bone cement bone repair technology to innovatively carry out correlation modeling and numerical calculation of the structure and permeability of bone-filled mesh bags and fractured vertebrae.

[0023] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0024] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0025] Figure 1 This is a schematic diagram of a bone cement injection device involved in an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of a fractured vertebral body model involved in the embodiments of the present invention;

[0027] Figure 3 This is a schematic diagram of a vertebral body model after bone cement is injected using a mesh bag molding technique, as described in an embodiment of the present invention.

[0028] Figure 4 This is the technical route for structural correlation modeling and bone cement dispersion distribution optimization design of bone filling mesh bags and fractured vertebral bodies involved in the embodiments of the present invention;

[0029] Figure 5 This is a graph showing the relationship between bone cement injection pressure and dispersion coefficient in Example 1 of this invention;

[0030] Figure 6 This is a graph showing the relationship between the settling time and the diffusion coefficient of bone cement in Example 2 of this invention;

[0031] Figure 7 This is a graph showing the relationship between the mesh diameter and the diffusion coefficient of the bone-filled mesh bag in Example 3 of the present invention.

[0032] Among them, 1: spinous process; 2: mastoid process; 3: bone cement pusher; 4: bone cement injection tube; 5: working channel; 6: transverse process; 7: bone filling mesh bag; 8: cortical bone; 9: cancellous bone; 10: mesh bag micropores; 11: vertebral foramen; 12: fractured vertebral body; 13: fracture fissure. Detailed Implementation

[0033] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0034] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0035] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0036] Example 1

[0037] Reference Figure 4 This embodiment provides a numerical simulation method for pressure leaching and diffusion of bone cement, which specifically includes the following steps:

[0038] Step 1: Obtain relevant parameters of the bone-filled mesh bag and the fractured vertebral body, and construct a numerical simulation model of the bone-filled mesh bag and the fractured vertebral body.

[0039] The simulation of the bone-filled mesh bag and the fractured vertebral body was performed using numerical simulation software. The formulation of each dose of the bone cement, taking SpinePlex radiopaque bone cement as an example, comprises 20g of powder and 10ml of liquid. The 20g sterile powder contains: 58.3% methyl methacrylate-styrene copolymer, 11.7% methyl methacrylate, and 30% barium sulfate. The 10ml sterile liquid contains: 97.4% methyl methacrylate, 2.6% N,N-dimethylaniline, and 75±15ppm hydroquinone.

[0040] The bone-filled mesh bag is made of polyethylene terephthalate (PET) material, which has good biocompatibility and can be directly placed in the body. Its surface is covered with mesh holes with a diameter of about 100μm, allowing a small portion of the bone cement injected into the mesh bag to seep out and anchor the cancellous bone. It is available in single-layer and double-layer specifications, and the appropriate number of layers, mesh hole diameter and mesh bag size can be selected according to the fracture situation to control the injection pressure and injection volume of bone cement.

[0041] This embodiment establishes simulation models of bone-filled mesh bags and fractured vertebrae based on computational fluid dynamics and biomedical materials science. Numerical analysis is performed on the flow characteristics of bone cement within the bone-filled mesh bag and the microenvironment of the fractured vertebrae. The flow field data is processed according to Darcy's law to obtain the equivalent permeability and its distribution in the bone-filled mesh bag and fractured vertebrae. The focus is on analyzing the influence of the bone-filled mesh bag structure and the fractured vertebrae structure on their permeability. Sensitivity analysis and scaling theory are introduced to reveal the structural influencing factors and their contribution rates on permeability and its distribution. A unified model relating the permeability and its distribution in the bone-filled mesh bag and fractured vertebrae to key structural parameters is established, taking into account the influence of different structural parameters.

[0042] Step 2: Based on the numerical simulation model and bone cement parameters, porous media permeability mechanics and computational fluid dynamics are used to calculate the equivalent permeability and its distribution in the bone-filled mesh bag and the fractured vertebral body, respectively. The flow process of bone cement within the microenvironment of the bone-filled mesh bag and the fractured vertebral body is numerically simulated, and the dispersion distribution of the bone cement is predicted. The dispersion distribution is determined by the dispersion coefficient, where the dispersion coefficient = dispersion volume / injection volume.

[0043] In step 2, porous media flow mechanics is used to describe the process of bone cement seeping out of the micropores of the bone-filled mesh bag under pressure, simulating and calculating the equivalent permeability and its distribution of the bone-filled mesh bag. Specifically, the process includes: using a porous media model to simulate the resistance of the bone-filled mesh bag wall to the rheology of the bone cement; based on porous media flow mechanics, setting the fluid domain near the bone-filled mesh bag wall as a porous medium; providing the continuity equation, standard flow equation, and momentum conservation equation for this fluid domain; and then using numerical methods to solve the continuity equation, standard flow equation, and momentum conservation equation in three-dimensional space to obtain numerical results for physical quantities such as the flow velocity and seepage rate of the bone cement, ultimately calculating the equivalent permeability of the bone-filled mesh bag.

[0044] In step 2, computational fluid dynamics is used to describe the non-uniform diffusion process of bone cement after it seeps out of the bone-filled mesh bag within the microenvironment of the fractured vertebral body, simulating and calculating the equivalent permeability and distribution of the fractured vertebral body. The process specifically includes:

[0045] Based on computational fluid dynamics, the continuity equation, motion equation, and boundary conditions of bone cement in the microenvironment of the fractured vertebra are given. Then, the continuity equation and motion equation are numerically solved in three-dimensional space to obtain the numerical results of physical quantities such as the flow velocity and pressure of bone cement. Finally, the equivalent permeability of the fractured vertebra is calculated.

[0046] The flow process of bone cement within the microenvironment of the bone-filled mesh bag and the fractured vertebra was numerically simulated based on Darcy's law.

[0047] This embodiment uses the aforementioned structure-related model of permeability and its distribution. Based on the specific structure of the bone-filled mesh bag and the fractured vertebral body, the permeability and its distribution of the bone-filled mesh bag and the diffusion rate and its distribution of the fractured vertebral body are numerically calculated. These permeability performance data are substituted into the Darcy formula to numerically simulate the process of bone cement seeping out of the bone-filled mesh bag. The focus is on analyzing the spatial flow characteristics of bone cement seeping out of the bone-filled mesh bag and after seepage in the microenvironment of the fractured vertebral body, as well as the evolution of the fluid front.

[0048] Step 3: Obtain the spatial diffusion distribution morphology of bone cement in the actual fractured vertebral body microenvironment under the same numerical simulation conditions, and compare it with the predicted bone cement diffusion distribution to optimize the design variables, so as to use the optimized design variables as the injection conditions for actual clinical surgery.

[0049] The design variables include the injection pressure and viscosity of bone cement and the mesh diameter of the bone-filled mesh bag. The objective function for optimization is the dispersion distribution of bone cement.

[0050] The spatial diffusion distribution morphology of bone cement in the actual fractured vertebral microenvironment, under the same numerical simulation conditions, was obtained based on an in vitro experiment involving the injection of bone cement into the fractured vertebral body using a mesh bag technique. Specifically, the fractured vertebral body was scanned using medical CT, with the scanning range including the bone-filled mesh bag and the bone cement within the fractured vertebral microenvironment. The raw data was then imported into a workstation to measure and calculate the diffusion volume of the bone cement. Based on the actual amount of bone cement injected in the experiment, the diffusion coefficient of the bone cement was obtained. From the perspective of experimental research, the permeability of the bone-filled mesh bag and its structural correlation, as well as the diffusion rate of the fractured vertebral body structure and its structural correlation, were derived. CT imaging technology was used to obtain the actual diffusion distribution morphology of bone cement in the fractured vertebral microenvironment. By combining the experimental results with theoretical analysis and numerical simulation results, the scientific laws governing the pressure-induced seepage of bone cement from the micropores of the bone-filled mesh bag and its non-uniform spatial diffusion within the fractured vertebral microenvironment were developed.

[0051] The ex vivo experiment specifically refers to injecting bone cement into a fractured vertebral body model using a mesh bag technique. This fractured vertebral body is identical to the fractured vertebral body model in the numerical simulation. The entire procedure is performed under the monitoring of medical imaging equipment such as a C-arm X-ray machine. A bilateral pedicle puncture approach is used, and the puncture point is located under fluoroscopy. A puncture needle (with a core) is inserted into the target fractured vertebral body through the pedicle. When the puncture needle passes approximately 5 mm beyond the posterior edge of the vertebral body, the core is removed. A vertebral drill is inserted and drilled along the outer cannula to a depth of 3-5 mm from the anterior edge of the vertebral body, then removed. The introducer connected to the bone-filled mesh bag is inserted into the cannula, so that the front end of the mesh bag reaches approximately 3 mm from the anterior edge of the vertebral body, and the inner core is removed. A bone cement injector is connected, and bone cement is gradually injected. The expansion of the mesh bag within the vertebral body and the leakage of bone cement from the mesh bag are observed. Once satisfactory, the injection is stopped. The extension tube is removed, and when the bone cement changes from a viscous state to a dough-like state, the introducer is rotated counterclockwise to separate it from the mesh bag and then withdrawn. Then insert the needle core and pull it out together with the cannula, leaving the mesh bag inside the fractured vertebra.

[0052] The comparative method refers to comparing theoretical analysis, numerical simulation results, and experimental test results under the same material parameters, process parameters, and other conditions. The numerical simulation methods and theories are modified based on the experimental test results, and the mathematical models and algorithms are improved.

[0053] The viscosity of bone cement increases with the processing time. After the bone cement is prepared, it is in a thin stage within 0-1 minute; a viscous stage within 1-5 minutes, during which bone cement can be injected; a hardening stage within 5-7 minutes; and a polymerization and heat generation stage within 7-12 minutes. The viscosity of bone cement can be indirectly reflected by the settling time after preparation.

[0054] Among them, the mesh diameter of the bone-filled mesh bag can affect the resistance coefficient in the porous media seepage theory; the smaller the mesh, the greater the resistance coefficient.

[0055] The practical clinical application of bone cement refers to the use of different injection parameters based on the patient's vertebral fracture status. Vertebral fracture status is mainly categorized based on MRI results as follows: no significant compression, slight compression (compression less than 1 / 3), vertebral compression (compression greater than 1 / 3 but less than 2 / 3), and severe vertebral compression (compression greater than 2 / 3). In cases of no significant or slight vertebral compression, bone cement can be injected at a lower viscosity. In cases of vertebral compression or severe compression, bone cement must be injected at a higher viscosity; otherwise, leakage is likely to occur.

[0056] This embodiment is based on numerical simulation technology of bone cement seepage into the bone-filled mesh bag and non-uniform dispersion in the microenvironment of the fractured vertebra. Sensitivity analysis and multi-objective optimization design are performed on physical quantities such as the mesh diameter of the bone-filled mesh bag, the viscosity of bone cement, the injection pressure, and the dispersion coefficient to improve the uniformity of bone cement dispersion in the microenvironment of the fractured vertebra.

[0057] In one or more embodiments, the numerical simulation method further includes:

[0058] Visual simulation of bone cement exudation under pressure into the bone-filling mesh bag and the non-uniform diffusion process within the microenvironment of the fractured vertebral body after exudation into the mesh bag.

[0059] For example, virtual reality technology can be used to visualize and simulate the non-uniform diffusion process of bone cement in the microenvironment of the fractured vertebra after it has been compressed and leached out of the bone-filled mesh bag, and to predict the diffusion distribution of bone cement.

[0060] This embodiment also conducts numerical analysis on the formation process and influencing factors of bone cement diffusion distribution: Based on the numerical simulation results of bone cement exudation from the bone-filling mesh bag and non-uniform diffusion in the microenvironment of the fractured vertebral body, the interactive, immersive, and imaginative advantages of virtual reality technology are utilized to visualize and simulate the dynamic exudation and diffusion process of bone cement. The evolution characteristics of bone cement exudation from the bone-filling mesh bag and non-uniform diffusion in the microenvironment of the fractured vertebral body are displayed in graphical ways such as 3D animation, cross-sectional views, and contour maps. The formation process of bone cement exudation from the bone-filling mesh bag and non-uniform diffusion in the microenvironment of the fractured vertebral body is vividly demonstrated, and the mechanism and influencing factors of bone cement seepage and diffusion are explored, realizing the integrated numerical analysis of bone cement pressure exudation-non-uniform diffusion.

[0061] This embodiment, based on numerical simulation and optimization design results of the pressure-induced leakage of bone cement from the micropores of the bone-filled mesh bag and its non-uniform diffusion within the microenvironment of the fractured vertebral body, provides guidance for injection conditions in actual clinical applications, such as injection time, injection pressure, viscosity, and mesh diameter of the bone-filled mesh bag. The aim is to improve the diffusion distribution of bone cement while minimizing leakage, enhance the biomechanical properties of the fractured vertebral body, and ultimately improve the therapeutic effect of bone cement treatment.

[0062] In other embodiments, the numerical simulation method of this embodiment can also be used for sensitivity analysis. Sensitivity analysis involves first calculating a numerical simulation result, denoted as A; then changing a physical quantity such as bone cement injection pressure, bone cement viscosity, or the mesh diameter of the bone-filled mesh bag, and performing the numerical simulation again to obtain another simulation result, denoted as B. By changing the initial value definition or calculation formula of the same physical quantity and repeating the numerical simulation process, a series of simulation results can be obtained. These results are plotted on the vertical axis, and the changes in the physical quantity are plotted on the horizontal axis (e.g., bar chart, line chart, scatter plot, etc.) or listed. The degree of influence of the physical quantity on the numerical simulation result is determined based on the trend of the changes in the chart; this is the sensitivity analysis of that physical quantity.

[0063] This embodiment employs a combination of theoretical analysis, numerical simulation, and experimental research to investigate the process of bone cement seeping out of the micropores of a bone-filled mesh bag under pressure and its non-uniform dispersion within the microenvironment of the fractured vertebral body after leakage. The focus is on analyzing the influence of the bone-filled mesh bag structure on permeability and its spatial distribution. A mathematical model is established to correlate permeability and its distribution with the structure. Numerical simulations of the mesoscopic and macroscopic flow behavior of bone cement are used to reveal the mechanism and patterns of bone cement seeping out of the micropores of the bone-filled mesh bag under pressure and its non-uniform dispersion within the microenvironment of the fractured vertebral body after leakage. A collaborative optimization design method is provided for the permeability of the bone-filled mesh bag, the formulation of the bone cement, the injection pressure and time of the bone cement, and the dispersion distribution of the bone cement. Furthermore, the results of the numerical simulation and optimization design guide practical clinical applications.

[0064] The following examples illustrate the numerical simulation method for compressive leaching and diffusion of bone cement.

[0065] Example 1:

[0066] Figure 1 A schematic diagram of a bone cement injection device is provided; wherein, the bone cement injection device includes a bone cement pusher 3, a bone cement injection tube 4, a working channel 5, and a bone filling mesh bag 7; the bone filling mesh bag 7 is provided with mesh bag micropores 10. Figure 2 A schematic diagram of a fractured vertebral body model is provided. Figure 3A vertebral model after bone cement injection using the mesh bag technique is presented. The fractured vertebral model includes the spinous process 1, mastoid process 2, transverse process 6, cortical bone 8, cancellous bone 9, and vertebral foramen 11; in this example, SpinePlex radiopaque bone cement is used by default.

[0067] Specific numerical simulation and experimental procedures:

[0068] (1) Use CT scans to obtain CT data and output tomographic images for saving. Then, use the image editing function built into the medical imaging control software to construct a three-dimensional geometric model of the fractured vertebra, calculate the 3D model, and perform simple smoothing.

[0069] (2) Import the 3D model of the fractured vertebral body into the numerical simulation software, assign material properties to each component, and ensure that the material of the same component is uniform and homogeneous. Set the bone filling mesh bag area as a porous medium area and input the bone cement material parameters.

[0070] (3) Five sets of calculation examples were set up, with injection pressures of 8, 9, 10, 11 and 12 atm (standard atmospheric pressure), bone cement viscosity set to the bone cement viscosity after a standing time of 3 min, and the mesh diameter of the bone filling mesh bag of 100 μm. With other conditions fixed, the equivalent permeability of the bone filling mesh bag and the fractured vertebral body was calculated. Then, the process of bone cement seeping out of the micropores of the bone filling mesh bag under pressure and non-uniformly dispersing in the microenvironment of the fractured vertebral body was numerically simulated.

[0071] (4) By using the post-processing function of numerical simulation software, the process of bone cement oozing out of the bone filling mesh bag under pressure and flowing dynamically in the microenvironment of the fractured vertebral body is visualized, and the relationship between bone cement injection pressure and bone cement oozing amount and diffusion distribution is obtained.

[0072] (5) The fractured vertebral body used for modeling was used to carry out in vitro experiments. Bone cement was injected into the fractured vertebral body using a mesh bag forming technique. Five control experiments were set up with injection pressures of 8, 9, 10, 11 and 12 atm, respectively. After the bone cement was prepared, it was left to stand for 3 minutes. The mesh diameter of the bone filling mesh bag was 100 μm. All other conditions were constant. Then, CT scan was used to obtain the diffusion distribution of bone cement in the fractured vertebral body during the experiment. The experimental and simulation results were compared to obtain the relationship between bone cement injection pressure and diffusion distribution.

[0073] Example 2:

[0074] (1) Use CT scans to obtain CT data and output tomographic images for saving. Then, use the image editing function built into the medical imaging control software to construct a three-dimensional geometric model of the fractured vertebra, calculate the 3D model, and perform simple smoothing.

[0075] (2) Import the 3D model of the fractured vertebral body into the numerical simulation software, assign material properties to each component, and ensure that the material of the same component is uniform and homogeneous. Set the bone filling mesh bag area as a porous medium area and input the bone cement material parameters.

[0076] (3) After the bone cement is prepared, the viscosity of the bone cement is measured at 1, 2, 3, 4 and 5 min respectively. Five sets of calculation cases are set up with the bone cement injection pressure of 10 atm, the mesh diameter of the bone filling mesh bag of 100 μm and other conditions being constant. The viscosity values ​​are input into the numerical simulation software to calculate the equivalent permeability of the bone filling mesh bag and the fractured vertebral body. Then, the process of bone cement seeping out of the micropores of the bone filling mesh bag under pressure and the non-uniform diffusion process in the microenvironment of the fractured vertebral body is numerically simulated.

[0077] (4) By using the post-processing function of numerical simulation software, the dynamic flow process of bone cement from the bone-filled mesh bag under pressure and in the microenvironment of the fractured vertebral body is visualized, and the relationship between bone cement viscosity and bone cement exudation and diffusion distribution is obtained.

[0078] (5) The fractured vertebral bodies used for modeling were used for in vitro experiments. Bone cement was injected into the fractured vertebral bodies using a mesh bag formation technique. Five control experiments were set up. After the bone cement was prepared, it was allowed to stand for 1, 2, 3, 4, and 5 minutes, respectively. The injection pressure of the bone cement was 10 atm, and the mesh diameter of the bone-filled mesh bag was 100 μm. All other conditions were kept constant. Then, CT scans were used to obtain the diffusion distribution of bone cement in the fractured vertebral bodies during the experiment. The experimental and simulation results were compared to obtain the relationship between bone cement viscosity and diffusion distribution.

[0079] Example 3:

[0080] (1) Use CT scans to obtain CT data and output tomographic images for saving. Then, use the image editing function built into the medical imaging control software to construct a three-dimensional geometric model of the fractured vertebra, calculate the 3D model, and perform simple smoothing.

[0081] (2) Import the 3D model of the fractured vertebral body into the numerical simulation software, assign material properties to each component, and ensure that the material of the same component is uniform and homogeneous. Set the bone filling mesh bag area as a porous medium area and input the bone cement material parameters.

[0082] (3) Prepare five different types of bone-filled mesh bags with mesh diameters of 80, 90, 100, 110, and 120 μm, respectively, and then measure the resistance coefficient through a fabric permeation experiment. Set up five control cases with a bone cement injection pressure of 10 atm and a viscosity set at the viscosity value after a standing time of 3 min. Keep other conditions constant, input the resistance coefficient into numerical simulation software, calculate the equivalent permeability of the bone-filled mesh bag and the fractured vertebral body, and then numerically simulate the process of bone cement seeping out of the micropores of the bone-filled mesh bag under pressure and the non-uniform diffusion process in the microenvironment of the fractured vertebral body.

[0083] (4) By using the post-processing function of numerical simulation software, the process of bone cement oozing out of the bone-filled mesh bag under pressure and flowing dynamically in the microenvironment of the fractured vertebral body is visualized, and the relationship between the diameter of the bone-filled mesh bag and the amount and diffusion distribution of bone cement oozing out is obtained.

[0084] (5) The fractured vertebral bodies used for modeling were used for in vitro experiments. Bone cement was injected into the fractured vertebral bodies using a mesh bag formation technique. Five control experiments were set up, using bone-filled mesh bags with mesh diameters of 80, 90, 100, 110, and 120 μm, respectively. The bone cement injection pressure was 10 atm, the bone cement settling time was 3 min, and other conditions were kept constant. Then, CT scans were used to obtain the diffusion distribution of bone cement in the fractured vertebral bodies during the experiments. The experimental and simulation results were compared to obtain the relationship between the diameter of the bone-filled mesh bag and the diffusion distribution.

[0085] Figure 5 , Figure 6 , Figure 7 The figures show the relationship between simulation and experimental results for bone cement injection pressure, bone cement settling time, mesh diameter of the bone-filled mesh bag, and the bone cement dispersion coefficient. Figure 5 , Figure 6 and Figure 7 As can be seen, the simulation results are close to the experimental results, indicating the rationality of the mathematical model and numerical simulation. The higher the injection pressure of the bone cement, the better its dispersion distribution; the longer the settling time after mixing the bone cement, the higher its viscosity and the worse its dispersion distribution; the larger the mesh diameter of the bone-filling mesh bag, the better the dispersion distribution. Comparing the three figures, it can be found that the settling time of the bone cement has the most significant impact on its dispersion distribution, indicating that in actual surgical procedures, the viscosity of the bone cement is crucial to the pressure-induced exudation of the bone cement from the bone-filling mesh bag and the non-uniform dispersion process within the microenvironment of the fractured vertebral body.

[0086] Example 2

[0087] This embodiment provides a numerical simulation system for pressure leaching and diffusion of bone cement, which specifically includes the following modules:

[0088] The numerical simulation model construction module is used to obtain relevant parameters of the bone-filled mesh bag and the fractured vertebral body, and to construct a numerical simulation model of the bone-filled mesh bag and the fractured vertebral body.

[0089] The diffusion distribution prediction module is used to calculate the equivalent permeability and distribution of the bone-filled mesh bag and the fractured vertebral body based on the numerical simulation model and bone cement parameters, using porous media permeation mechanics and computational fluid dynamics respectively. It numerically simulates the spatial flow process of bone cement in the microenvironment of the bone-filled mesh bag and the fractured vertebral body, and predicts the diffusion distribution of bone cement.

[0090] The design variable optimization module is used to obtain the spatial diffusion distribution pattern of bone cement in the real fracture vertebral microenvironment under the same numerical simulation conditions, and compare it with the predicted bone cement diffusion distribution to optimize the design variables, so that the optimized design variables can be used as the injection conditions for actual clinical surgery.

[0091] The design variables include the injection pressure and viscosity of bone cement and the mesh diameter of the bone-filled mesh bag. The objective function for optimization is the dispersion distribution of bone cement.

[0092] The diffusion distribution is determined by the diffusion coefficient, where the diffusion coefficient = diffusion volume / injection volume.

[0093] It should be noted that each module in this embodiment corresponds one-to-one with each step in Embodiment 1, and their specific implementation processes are the same, so they will not be repeated here.

[0094] Example 3

[0095] This embodiment provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps in the numerical simulation method for compressive effusion and diffusion of bone cement as described above.

[0096] Example 4

[0097] This embodiment provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the steps in the numerical simulation method for pressure effusion and diffusion of bone cement as described above.

[0098] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, as well as combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0099] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A numerical simulation method of cement extrusion and dispersion under compression, characterized by, include: Obtain relevant parameters of the bone-filled mesh bag and the fractured vertebral body, and construct a numerical simulation model of the bone-filled mesh bag and the fractured vertebral body; Based on the numerical simulation model and bone cement parameters, porous media permeation mechanics is used to describe the process of bone cement seeping out of the micropores of the bone-filled mesh bag under pressure, and the equivalent permeability and its distribution of the bone-filled mesh bag are simulated and calculated. Computational fluid dynamics is used to describe the non-uniform diffusion process of bone cement in the microenvironment of the fractured vertebra after it seeps out of the bone-filled mesh bag, and the equivalent permeability and its distribution of the fractured vertebra are simulated and calculated. According to Darcy's law, the spatial flow process of bone cement in the microenvironment of the bone-filled mesh bag and the fractured vertebra is numerically simulated, and the diffusion distribution of bone cement is predicted. The spatial diffusion distribution morphology of bone cement in the actual fracture vertebral microenvironment with the same numerical simulation conditions was obtained, and it was compared with the predicted bone cement diffusion distribution to optimize the design variables, so that the optimized design variables could be used as the injection conditions for actual clinical surgery. The design variables include the injection pressure and viscosity of bone cement and the mesh diameter of the bone-filled mesh bag. The objective function for optimization is the dispersion distribution of bone cement.

2. The numerical simulation method for pressure efflux and diffusion of bone cement as described in claim 1, characterized in that, The diffusion distribution is determined by the diffusion coefficient, where the diffusion coefficient = diffusion volume / injection volume.

3. The numerical simulation method for pressure-induced efflux and diffusion of bone cement as described in claim 1, characterized in that, The numerical simulation method also includes: Visual simulation of bone cement exudation under pressure into the bone-filling mesh bag and the non-uniform diffusion process within the microenvironment of the fractured vertebral body after exudation into the mesh bag.

4. A numerical simulation system for pressure-induced leaching and dispersion of bone cement, characterized in that, include: The numerical simulation model construction module is used to obtain relevant parameters of the bone-filled mesh bag and the fractured vertebral body, and to construct a numerical simulation model of the bone-filled mesh bag and the fractured vertebral body. The diffusion distribution prediction module is used to describe the process of bone cement seeping out of the micropores of the bone-filled mesh bag under pressure, based on the numerical simulation model and bone cement parameters, using porous media permeation mechanics to simulate and calculate the equivalent permeability and distribution of the bone-filled mesh bag; using computational fluid dynamics to describe the non-uniform diffusion process of bone cement in the microenvironment of the fractured vertebral body after seeping out of the bone-filled mesh bag, simulating and calculating the equivalent permeability and distribution of the fractured vertebral body; and using Darcy's law to numerically simulate the flow process of bone cement in the microenvironment of the bone-filled mesh bag and the fractured vertebral body, predicting the diffusion distribution of bone cement. The design variable optimization module is used to obtain the spatial diffusion distribution pattern of bone cement in the real fracture vertebral microenvironment under the same numerical simulation conditions, and compare it with the predicted bone cement diffusion distribution to optimize the design variables, so that the optimized design variables can be used as the injection conditions for actual clinical surgery. The design variables include the injection pressure and viscosity of bone cement and the mesh diameter of the bone-filled mesh bag. The objective function for optimization is the dispersion distribution of bone cement.

5. The numerical simulation system for pressure-induced efflux and diffusion of bone cement as described in claim 4, characterized in that, The diffusion distribution is determined by the diffusion coefficient, where the diffusion coefficient = diffusion volume / injection volume.

6. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the program implements the steps in the numerical simulation method for compressive leaching and diffusion of bone cement as described in any one of claims 1-3.

7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps in the numerical simulation method for pressure leaching and diffusion of bone cement as described in any one of claims 1-3.

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