Numerical simulation optimization method and system for bone repair shaping of mesh bag type bone cement

Abstract

The application belongs to the technical field of bone repair, and provides a numerical simulation optimization method and system for bone repair shaping of a mesh bag type bone cement. The method comprises the following steps: obtaining physical performance parameters, initial values and boundary conditions of the mesh bag type bone cement; performing numerical simulation on the processes of bone cement injection, diffusion and solidification based on a bone repair shaping mathematical model of the mesh bag type bone cement, to obtain simulation results under the current bone repair shaping mathematical model parameters; changing the physical performance parameter values, performing multi-objective optimization and sensitivity analysis of a single physical performance parameter, determining multi-objective optimal solutions under the influence of multiple physical quantities and the influence degree of the corresponding physical performance parameters on the numerical simulation process, so as to obtain a bone repair shaping scheme meeting the bone cement injection conditions and diffusion effects in actual clinical applications.

Description

Technical Field

[0001] This invention belongs to the field of bone repair technology, and in particular relates to a numerical simulation optimization method and system for bone repair and shaping using mesh bag type bone cement. 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] Currently, orthopedic clinical treatment often utilizes bone repair materials (injectable bone cement) to repair damaged bone structures and rebuild bone stability. Besides bioactive ceramics, various types of bone cement are also available as bone repair materials. In the 1980s, bone cement was introduced into clinical treatment for osteoporotic fractures, gradually developing into percutaneous vertebroplasty (PVP). In recent years, vesselplasty has gained attention as another bone repair technique. The procedure involves inserting a bone-filled mesh bag into the vertebral body through a working channel. Bone cement is then injected layer by layer into the mesh bag. Once the injection pressure reaches a certain level, the bone cement overflows through the mesh and seeps into the surrounding bone tissue, forming a microscopic interlocking structure that strengthens the vertebral body, relieves pain, and counteracts shear forces. However, bone mesh bag reconstruction also has its limitations. Because the bone-filled mesh bag is permanently placed in the vertebral body and cannot be reused, the material cost is high. The mesh bag has a small pore size and is compressed by surrounding bone fragments and cancellous bone, so the amount of bone cement seeping through the mesh at the fracture site is small. Although the bone-filled mesh bag has a good effect on reinforcing the vertebral body in the short term, there may be a risk of loosening in the long term.

[0004] Although the bone repair methods described above are widely used in clinical practice, the current surgical procedures largely depend on the surgeon's clinical experience and skills. When using bone mesh bag grafting for clinical bone repair surgery on patients with osteoporotic vertebral fractures, risks such as bone cement leakage and postoperative vertebral collapse still exist. Therefore, it is necessary to optimize and improve the bone repair and shaping process of mesh bag-type bone cement, clarify the corresponding physical quantities in the bone repair and shaping process, and develop personalized bone repair plans. Summary of the Invention

[0005] To address the technical problems mentioned above, this invention provides a numerical simulation optimization method and system for bone repair and shaping using mesh bag-type bone cement. This method can establish a mathematical model and numerical calculation method for the entire process of bone repair and shaping using mesh bag-type bone cement, from injection and dispersion to curing, thus providing guidance for research on bone repair and shaping technology based on bone cement.

[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 optimization method for bone repair and shaping using mesh bag-type bone cement, comprising:

[0008] Obtain the physical property parameters, initial values, and boundary conditions of the mesh bag bone cement;

[0009] The mathematical model of bone repair and shaping based on mesh bag bone cement is used to numerically simulate the process of bone cement injection, dispersion and curing, and the simulation results are obtained under the current parameters of the mathematical model of bone repair and shaping.

[0010] By changing the values ​​of physical performance parameters, performing multi-objective optimization and sensitivity analysis of individual physical performance parameters, the optimal solution for multiple objectives under the influence of multiple physical quantities and the degree of influence of corresponding physical performance parameters on the numerical simulation process are determined, thereby obtaining a bone repair and shaping scheme that meets the conditions for bone cement injection and diffusion effect in actual clinical applications.

[0011] A second aspect of the present invention provides a numerical simulation optimization system for bone repair and shaping using mesh bag-type bone cement, comprising:

[0012] The parameter acquisition module is used to acquire the physical performance parameters, initial values, and boundary conditions of the mesh bag bone cement.

[0013] The numerical simulation module is used to numerically simulate the process of bone cement injection, dispersion and curing based on the bone repair and shaping mathematical model of mesh bag bone cement, and obtain the simulation results under the current bone repair and shaping mathematical model parameters.

[0014] The parameter optimization module is used to perform multi-objective optimization and sensitivity analysis of individual physical performance parameters by changing the values ​​of physical performance parameters. It determines the optimal solution of the multi-objective under the influence of multiple physical quantities and the degree of influence of the corresponding physical performance parameters on the numerical simulation process, thereby obtaining a bone repair and shaping scheme that meets the conditions for bone cement injection and diffusion effect in actual clinical applications.

[0015] 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 optimization method for bone repair and shaping of mesh-bag bone cement as described above.

[0016] 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 optimization method for bone repair and shaping using mesh bag-type bone cement as described above.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] (1) This invention provides a numerical simulation optimization method for bone repair and shaping of mesh bag bone cement. Based on the mathematical model of bone repair and shaping of mesh bag bone cement, the process of bone cement injection, diffusion and curing is numerically simulated. A mathematical model and numerical calculation method for bone repair and shaping of mesh bag bone cement from injection, diffusion to curing are creatively established. By changing the physical performance parameter values, multi-objective optimization and sensitivity analysis of a single physical performance parameter are carried out to obtain a bone repair and shaping scheme that meets the injection conditions and diffusion effect of bone cement in actual clinical applications, providing guidance for the research of bone repair and shaping technology based on bone cement.

[0019] (2) Based on the numerical simulation technology of bone repair and shaping of the entire process of injection, diffusion and curing of mesh bag bone cement, this invention establishes an optimized design system that includes bone cement injection process and bone cement curing condition control, providing ideas for reducing the cost of using mesh bag bone cement bone repair and shaping technology and developing new bone cement repair and shaping technology.

[0020] (3) The numerical simulation optimization technology of bone repair and shaping based on mesh bag bone cement can also be used in conjunction with fiber Bragg grating online monitoring technology and device to complement and promote each other, and jointly improve the surgical treatment effect and patient satisfaction of mesh bag bone cement bone repair and shaping technology.

[0021] 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

[0022] 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.

[0023] Figure 1 This is the numerical simulation result of the monomer concentration of the bone cement polymerization reaction in Example 1 of the present invention changing over time;

[0024] Figure 2 This is the change in the degree of polymerization of bone cement over time in Example 2 of the present invention, as shown in the numerical simulation results.

[0025] Figure 3 This is the change in the numerical simulation results of the reaction heat release of the bone cement polymerization reaction over time in Example 3 of the present invention;

[0026] Figure 4 This is a schematic diagram of the bone filling mesh bag and forming supporting device involved in the embodiments of the present invention;

[0027] Figure 5This is a schematic diagram of the cross-sectional outline and internal structure of the human thoracic and lumbar vertebrae involved in the embodiments of the present invention.

[0028] Figure 6 This is a schematic diagram of bone repair and shaping using mesh bag type bone cement according to an embodiment of the present invention.

[0029] Figure 7 This is a numerical simulation technology route for bone repair and shaping using mesh bag type bone cement involved in the embodiments of the present invention.

[0030] Figure 8 This is a numerical simulation flowchart of bone repair and shaping using mesh bag type bone cement, as described in the embodiments of the present invention.

[0031] Figure 9 This is an optimized design technology route for bone repair and shaping using mesh bag type bone cement, as described in the embodiments 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. 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] Osteoporotic fractures (fragility fractures) are fractures caused by decreased bone density and quality, leading to reduced bone strength and increased fragility. These fractures occur even with minor trauma and are essentially pathological fractures, representing the most serious complication of osteoporosis. Bone density characterizes the degree of osteoporosis, clinically expressed using the T-score. A normal T-score ranges from -1 to 1. A T-score greater than -1 indicates normal bone density, while a T-score less than -1 signifies decreased bone mass. A T-score less than -2.5 indicates osteoporosis. Common sites of osteoporotic fractures include the spine, hip, distal radius, and proximal humerus, with spinal fractures being the most frequent, known as osteoporotic vertebral compression fractures.

[0037] Currently, common bone cement repair materials include polymethyl methacrylate (PMMA) bone cement, calcium phosphate (CPC) bone cement, calcium sulfate bone cement, and composite bone cement. PMMA bone cement has the advantages of low price, convenient preparation, and rapid preparation during surgery; after polymerization, it has high mechanical strength and can quickly relieve pain by stabilizing fractures.

[0038] The basic formulations of PMMA bone cement are exemplified by SpinePlex bone cement and Osteopalv bone cement.

[0039] Each dose of SpinePlex bone cement comprises 20g of powder and 10ml of liquid. The 20g sterile powder contains: 2.3g of polymethyl methacrylate microspheres, 11.7g of methyl methacrylate-styrene copolymer containing benzoyl peroxide (1.5%), and 6.0g of barium sulfate (contrast agent). The 10ml sterile liquid contains: 9.75ml of methyl methacrylate (monomer), 0.25ml of N,N-dimethyl-p-toluidine (catalyst), and 6–9μg of hydroquinone (stabilizer). Hydroquinone is a white needle-like crystal at room temperature; due to its extremely small concentration, it is dissolved in the 10ml sterile liquid with negligible volume change.

[0040] Each dose of OSTEOPALV bone cement contains 26g of powder and 10ml of liquid, both sterilized with ethylene oxide. The 26g sterilized powder includes 14.2g of methyl acrylate-methyl methacrylate copolymer, 11.7g of zirconium dioxide (contrast agent), 0.1g of benzoyl peroxide (initiator), and a trace amount of copper chlorophyllin. The 10ml liquid includes 9.2g of methyl methacrylate monomer and 0.2g of N,N-dimethyl-p-toluidine (catalyst), as well as trace amounts of copper chlorophyllin and hydroquinone (stabilizer). Copper chlorophyllin is used as a staining agent to ensure the bone cement is clearly visible in the surgical area; hydroquinone is used to slow down the polymerization rate of the bone cement at room temperature.

[0041] This invention utilizes computer software and numerical analysis theory to abstract specific mathematical models from complex practical problems for numerical simulation, overcoming the shortcomings of traditional methods such as long research times and complex physical variables. For the bone repair and shaping process of PMMA bone cement, a reasonable and effective mathematical model was established, and numerical simulation was performed using computer software. This model complements and promotes experimental methods, achieving unexpected results. This invention combines numerical simulation and optimization design of bone repair and shaping based on bone cement with practical clinical applications, which is of significant value in promoting the substantial advancement of clinical bone repair technology.

[0042] Example 1

[0043] From a scientific perspective, during the polymerization and molding process of PMMA bone cement, the diffusion-limited polymerization reaction, the morphological formation and evolution of the multiphase bone cement system accompanying the polymerization reaction, and the physical and chemical rheological processes of bone cement all occur primarily in a semi-closed state. Bone cement is typically exposed to complex body fluid environments that are neither isothermal nor isobaric, and its viscosity can change abruptly within a short period. Therefore, it becomes extremely difficult to study the chemical reaction kinetics and molecular evolution mechanisms of bone cement, the morphological formation kinetics of multiphase bone cement systems, the physical and chemical rheological laws, and the evolution of its physicochemical properties in situ and in real-time.

[0044] From a technical perspective, once PMMA bone cement is injected into the fractured vertebral space, it undergoes a rapid polymerization reaction, typically transforming from a toothpaste-like fluid into a non-flowing solid within ten minutes, while also generating heat from the chemical reaction. This places extremely stringent technical requirements on heat transfer, preventing bone cement leakage and burns, and avoiding toxicity to healthy human tissues. Furthermore, the complex internal environment of the fractured vertebral body makes current bone mesh bag formation techniques difficult to effectively utilize for bone repair using various bone cement systems, hindering the widespread application of this technology in the clinical treatment of osteoporotic vertebral compression fractures.

[0045] To address the shortcomings of current bone repair and shaping technologies using mesh-type bone cement, this embodiment provides a numerical simulation optimization method for bone repair and shaping using mesh-type bone cement. The bone repair and shaping technology using mesh-type bone cement involved in this embodiment specifically refers to bone mesh-type shaping. The bone cement, before being injected into the fractured vertebral body, is in a viscous, stringy state, and is prepared by mixing polymer powder and liquid monomer in a specific ratio (preferably 2:1 for SpinePlex bone cement). The bone cement components involved in this invention include a solid powder composed of polymethyl methacrylate, an initiator (generally a free radical initiator, such as benzoyl peroxide, azobisisobutyronitrile, etc.), and a small amount of contrast agent (zirconia or barium sulfate), and a solution composed of methyl methacrylate monomer, other small molecule monomers, a catalyst (dimethyl-p-toluidine), and a stabilizer (hydroquinone).

[0046] In this embodiment, the PMMA bone cement is used surgically. The powder and liquid components are typically mixed uniformly at room temperature in a certain ratio (preferably 2:1 for SpinePlex bone cement), resulting in physical and chemical reactions. The physical reaction stage involves the dissolution and mixing of the liquid monomer and the solid powder; the chemical reaction stage can be divided into four phases:

[0047] ① Mixing period (porridge stage): 0-1 min, the powder and liquid dissolve and mix. The initiator in the solid phase (benzoyl peroxide (BPO) for SpinePlex bone cement) and the catalyst in the liquid phase (dimethyl-p-toluidine (DMPT) for SpinePlex bone cement) work synergistically to generate a large number of free radicals, thereby enabling the MMA monomer molecules to undergo rapid addition polymerization.

[0048] ② Waiting period (filament adhesion period): 1-3 minutes. In the early stage of the polymerization reaction, multi-chain polymers appear, their activity decreases, and they can be pulled out into filaments. Macroscopically, they appear as highly fluid, low-viscosity lumps, which is the earliest stage of injectable bone cement.

[0049] ③ Working period (forming stage): 3-5 minutes. As the reaction proceeds, the viscosity gradually increases until the dough stage is reached, at which point the surgical procedure of injecting bone cement can be performed.

[0050] ④ Hardening period (curing period): 5-12 minutes. The bone cement gradually hardens and its viscosity continues to increase. At this time, the temperature of the bone cement rises rapidly, and the heat generation reaches its peak. Finally, the fracture site is connected and fixed by the polymer solid block.

[0051] like Figure 8 and Figure 9 As shown, the numerical simulation optimization method for bone repair and shaping using mesh-type bone cement in this embodiment specifically includes the following steps:

[0052] Step 1: Obtain the physical property parameters, initial values, and boundary conditions of the mesh bag bone cement.

[0053] In practical implementation, the physical properties of mesh-bag bone cement include, but are not limited to, bone cement injection temperature, injection pressure, monomer concentration, degree of polymerization reaction, apparent viscosity of bone cement, polymerization reaction temperature, and chemical shrinkage rate; initial values ​​include the initial temperature, initial viscosity, and initial injection volume of bone cement; boundary conditions include the ambient temperature of the bone cement and the resistance to diffusion and flow of bone cement in trabeculae and cancellous bone.

[0054] Step 2: Based on the mathematical model of bone repair and shaping using mesh bag bone cement, numerical simulations are performed on the process of bone cement injection, dispersion and curing to obtain simulation results under the current parameters of the bone repair and shaping mathematical model.

[0055] The principle of bone mesh bag repair surgery is as follows: Figure 6 As shown, this involves utilizing the physical flow process of bone cement filling the bone-filling mesh bag, the physical diffusion process of bone cement seeping out of the mesh pores and anchoring with cancellous bone, and the chemical strengthening process of bone cement solidification to achieve the goal of fixing the fracture site and reconstructing bone stability. Then, software for numerical simulation of bone repair and shaping using current mesh bag-type bone cement will be developed, with initial boundary value conditions and parameters required for numerical calculations as input.

[0056] Next, at any spatial point and any time, a semi-implicit, decoupled numerical approximation method is used. Computer software iteratively solves the continuity equation, motion equation, chemical rheological constitutive equation, polymerization reaction kinetic equation, and polymerization degree expression, obtaining numerical simulation results of the bone cement temperature field, apparent viscosity field, monomer concentration field, and polymerization degree field from injection initiation to curing completion. For example, according to the law of conservation of mass, compared to before curing, the disordered monomer molecules after complete curing transform into tightly packed macromolecular chains, increasing the density of the bone cement and thus causing volume shrinkage. By inputting the volume shrinkage rate, the volume shrinkage strain of the bone cement at any time point and location can be numerically simulated.

[0057] In specific implementation, the bone repair and shaping mathematical model includes a bone cement injection mathematical model, a bone cement dispersion mathematical model, and a bone cement curing mathematical model, which are used to numerically simulate the processes of bone cement injection, dispersion, and curing, respectively.

[0058] The numerical simulation of bone cement injection is simplified as a heat transfer and material transport process of a three-dimensional viscous fluid transferring to the human body temperature environment at a certain set temperature.

[0059] Assuming no chemical reaction occurs, the initial and boundary conditions need to be defined during numerical simulation. The initial temperature of the bone cement, the body temperature, the convective heat transfer coefficient, and material properties such as the thermal conductivity and specific heat capacity of the bone cement are input to calculate the temperature field changes of the bone cement before and after it is injected into the fractured vertebrae of the patient.

[0060] The numerical simulation of bone cement dispersion is simplified to the physical seepage process of a three-dimensional viscous fluid in a porous medium.

[0061] Assuming no chemical reaction occurs, the simulation focuses solely on the pressure-induced seepage of bone cement from the pores of the mesh bag wall and its non-uniform spatial dispersion within the fracture environment. Due to the low permeability of bone tissue and the relatively open nature of the remaining areas of the fractured vertebral body, dispersion is minimal in the direct contact area between the mesh bag and bone tissue, but abundant in other areas. Numerical simulations require clearly defined initial and boundary conditions, inputting parameters such as the resistance coefficient of the porous medium, bone cement temperature, injection pressure, and initial viscosity of the bone cement. The equivalent permeability of bone cement through the mesh is then calculated to obtain numerical simulation results of the apparent viscosity field evolution of bone cement under the respective influences of temperature, pressure, and material structure.

[0062] The numerical simulation of bone cement solidification is simplified as a thermo-chemical-mechanical coupling process in which a three-dimensional viscous fluid containing an internal heat source undergoes a chemical reaction at a certain temperature and pressure, transforming from a fluid that can be drawn into strands or dough into a solid with increased hardness and strength, and generating volume shrinkage and internal stress.

[0063] Because the polymerization reaction of bone cement is very short and the injected volume is only a few milliliters, the polymerization temperature will not be too high. Therefore, the influence of thermal radiation is ignored, and only the heat convection and heat conduction processes are considered. In the computer simulation, it is necessary to define the initial and boundary conditions and input the material property parameters of the bone cement, including the density, specific heat capacity, thermal conductivity, and heat transfer coefficient of the bone cement as a function of the degree of polymerization and temperature, as well as the initial temperature and chemical shrinkage coefficient of the bone cement. This allows for the numerical simulation results of the temperature field, polymerization degree field, and internal stress field evolution during the bone cement curing process.

[0064] Step 3: By changing the values ​​of physical performance parameters, multi-objective optimization and sensitivity analysis of individual physical performance parameters are performed to determine the optimal solution of multi-objectives under the influence of multiple physical quantities and the degree of influence of the corresponding physical performance parameters on the numerical simulation process, thereby obtaining a bone repair and shaping scheme that meets the conditions for bone cement injection and diffusion effect in actual clinical applications.

[0065] By changing the values ​​of physical performance parameters, performing multi-objective optimization and sensitivity analysis of individual physical performance parameters, the dynamic evolution of physical performance parameters is used to demonstrate the bone repair and shaping process.

[0066] In practical implementation, the process of performing multi-objective optimization and sensitivity analysis of a single physical performance parameter by changing the values ​​of the physical performance parameters is as follows:

[0067] First, a mathematical model is abstracted from the real physical and chemical problems of bone repair and shaping using mesh-bag bone cement. Then, the initial and boundary conditions of the mathematical model are determined, along with the input parameters required for computer numerical calculation. Next, computer software is used to perform simulation, yielding the simulation result under the current mathematical model parameters, denoted as A. Subsequently, the initial value definition or calculation formula of a certain physical quantity (bone cement injection pressure, mesh bag pore size, bone cement injection volume, etc.) is changed, and the computer simulation is repeated to obtain another simulation result, denoted as B. This process is repeated again, changing the initial value definition or calculation formula of the same physical quantity, to obtain a series of simulation results. These results are plotted on the vertical axis, with the change in the physical quantity on the horizontal axis (e.g., bar chart, line chart, scatter plot, etc.) or listed. The influence of the physical quantity on the numerical simulation results is determined based on the trend of the chart, which is the sensitivity analysis of that physical quantity.

[0068] Similarly, by comparing and analyzing the numerical simulation results under conditions where multiple physical quantities are changed, the conditions corresponding to the optimal solution can be identified, thereby enabling multi-objective optimization design. For example, by using physical quantities such as bone cement injection pressure, initial viscosity of bone cement, and mesh bag pore size as constraints, and the bone cement dispersion coefficient as the objective function, the optimal solution of the objective function under the influence of multiple physical quantities can be found, i.e., the conditions corresponding to the optimal bone cement dispersion distribution.

[0069] Furthermore, the numerical simulation optimization technology for bone repair and shaping using mesh bag type bone cement involved in this embodiment can be combined with the online real-time monitoring method and device for the injection, diffusion, and curing process of bone cement at the fracture site using fiber optic gratings. On the one hand, the experimental data from online real-time monitoring of fiber optic gratings can be used to continuously correct the numerical simulation technology and optimize the design system, thereby improving the accuracy and practicality of the mathematical model. On the other hand, the numerical simulation results can also optimize the installation position of the online real-time monitoring device for fiber optic gratings, thereby improving the sensitivity and reliability of physical quantities such as temperature and strain measured by the fiber optic gratings.

[0070] This embodiment demonstrates, through the example of... Figure 7 Numerical simulations were performed on the bone repair and shaping of the mesh-bag type bone cement shown, revealing the influence of polymerization reaction on the physical and chemical rheological behavior of the bone cement system. A microscopic theoretical model of the rheology of the bone cement system under complex chemical and physical conditions was established, and physical quantities such as the heat of reaction, viscosity, and degree of polymerization of bone cement were dynamically calculated. Based on this, the control variable optimization theory was introduced to establish an optimization design system for the injection, dispersion, and curing process of PMMA bone cement. The core program of the PMMA bone cement injection, dispersion, and curing process optimization software was independently developed, thereby realizing the prediction of chemical reaction control, fluid rheological process regulation, and material property control in the PMMA bone cement injection, dispersion, and curing process.

[0071] Based on the knowledge of disciplines such as polymer chemistry and physics, polymer material rheology, computational mathematics, numerical heat transfer, material mechanics, orthopedics, and software engineering, and using computer software and numerical analysis methods, the present invention conducts numerical simulations of the rheological field, temperature field, chemical reaction field, and physical property field of bone cement in osteoporotic fracture vertebrae, and specifically solves the problem of the mutual influence among the degree of polymerization reaction, injection pressure, flow velocity, reaction heat intensity, bone cement viscosity, bone cement molecular weight, bone cement thermal conductivity, and bone cement specific heat capacity of bone cement. Thus, under the given initial and boundary conditions, the dynamic evolution of physical quantities such as flow velocity, pressure, temperature, reaction heat intensity, degree of polymerization reaction, molecular weight and its distribution, bone cement viscosity, bone cement thermal conductivity, and bone cement specific heat capacity in the compression polymerization process of the free radical polymerization system can be quantitatively obtained.

[0072] The numerical simulation technology and optimization design method involved in this embodiment are specifically used for the mesh bag forming operation of osteoporotic fractures in clinical practice. This is because bone cement injection treatment is mostly used for the elderly over 60 years old with varying degrees of osteoporosis, and generally, bone cement treatment methods are not adopted for fractures in young people.

[0073] This embodiment can achieve the on-demand design of bone cement injection conditions and dispersion effects in actual clinical applications. The so-called actual clinical applications refer to the scenarios of different osteoporosis degrees and different vertebral fracture compression degrees in clinical practice.

[0074] Specifically, in terms of the degree of osteoporosis, when the T value range is -2.5 < T < -1.0, that is, close to osteoporosis, most patients are postmenopausal primary women or men aged over 70 and under 80. In this case, a small amount of bone cement injection is required, and the bone cement is injected when it is relatively dilute; when the T value range is -3.5 < T < -2.5, that is, moderate osteoporosis, most patients are women over 60 years old and men over 80 years old. In this case, a large amount of bone cement injection is required, and the bone cement is injected when it is relatively thick; when the T value range is T < -3.5, that is, severe osteoporosis, a small amount of bone cement injection is required, and the bone cement is injected when it is relatively thick.

[0075] In terms of the severity of osteoporotic vertebral compression fractures, when the magnetic resonance imaging (MRI) results show no obvious compression, a large amount of bone cement injection is required, and it is injected when it is relatively dilute, with good dispersion effect; when the MRI results show slight compression, that is, the anterior vertebral body compression degree < 1 / 3, a relatively large amount of bone cement injection is required, and the bone cement is injected when it is relatively dilute, with a relatively good dispersion effect; when the MRI results show that the anterior vertebral body compression degree > 1 / 3 and < 2 / 3, a small amount of bone cement injection is required, and the bone cement is injected when it is relatively thick to improve dispersion; when the MRI results show that the anterior vertebral body compression degree > 2 / 3, a small amount of bone cement injection is required, and the bone cement is injected when it is relatively thick, which can reduce the leakage probability and improve the dispersion effect.

[0076] This embodiment utilizes numerical heat transfer, computational fluid dynamics, and other theoretical methods, employing computer software to numerically simulate the high-pressure injection of bone cement into an osteoporotic fracture site in the form of a mesh bag under given in vitro injection temperature and pressure. It also uses porous media permeation and computational fluid dynamics to numerically simulate the pressure-induced seepage of bone cement from the pores of the mesh bag wall and its non-uniform spatial dispersion within the fracture environment, under given pore size and injection volume. Furthermore, it leverages numerical heat transfer, computational fluid dynamics, and materials mechanics to numerically simulate the post-injection solidification process of bone cement through multi-physics field coupling of thermo-chemical-mechanical fields. This includes changes in the bone cement temperature field caused by the exothermic polymerization reaction, changes in the physical properties of the bone cement due to increased polymerization degree, and volume shrinkage and internal stress evolution before and after the polymerization reaction.

[0077] This embodiment optimizes the design of bone repair molding using mesh bag-type bone cement. It primarily involves sensitivity analysis and multi-objective optimization of physical quantities such as bone cement injection pressure, mesh bag pore size, monomer concentration, polymerization reaction degree, and polymerization reaction temperature. This aims to reduce problems such as bone cement leakage and bone tissue damage caused by bone cement exothermic reactions in current bone repair molding technologies, improve the clinical therapeutic effect of mesh bag-type bone cement bone repair molding, and further provide guidance for the development of novel bone repair molding technologies.

[0078] The numerical simulation processes for Examples 1 to 3 are given below. Figure 6 Schematic diagrams of bone repair and shaping using mesh bag-type bone cement are provided. These examples involve bone-filling mesh bags and shaping devices such as… Figure 4 As shown, in Figure 4 The bone-filled mesh bag and its forming apparatus include, in sequence, a bone cement pusher 3, a bone cement injection tube 4, a working channel 5, a bone-filled mesh bag 7, and mesh bag micropores 10. Figure 5 The cross-sectional outline and internal structure of the human thoracic and lumbar vertebrae involved are given. The human thoracic and lumbar vertebrae include the spinous process 1, mastoid process 2, transverse process 6, cortical bone 8, cancellous bone 9, and vertebral foramen 11.

[0079] Example 1: Numerical simulation of the evolution of the concentration field of bone cement monomers

[0080] A certain model, GT-01, bone-filling mesh bag consists of a delivery device and a mesh bag. The delivery device includes an injection tube, a core needle, and a push rod. The mesh bag is made of polyethylene terephthalate (PET) material, which has good biocompatibility. Its structure is a single-layer injection tube and a single-layer mesh bag, connected by a threaded connection. The mesh bag is 20mm long, with the front end fixed in a sealed state by a metal marker, and the tail end fixed to the metal delivery device. The mesh bag seat and end material are pure titanium TA2 conforming to the GB / T13810-2007 standard. The metal parts of the injection tube, core needle, push rod, etc., are S30408 ​​stainless steel conforming to the requirements of M in Table 2 of the YY / T 0294.1-2005 standard. The handle is made of ABS material. The product is sterilized with ethylene oxide. This product is used in conjunction with related surgical instruments to treat vertebral tumors, osteoporosis, or compression fractures of the lower thoracic and lumbar vertebrae caused by trauma.

[0081] This example uses SpinePlex bone cement, a GT-01 bone-filling mesh bag, and a 4.5mm diameter, 130mm long puncture needle to establish a working channel. During the procedure, the working channel is first established, and the injection tube and mesh bag are inserted into the collapsed vertebral body through this channel. Then, the bone cement powder and solution are mixed in a specific ratio to a porridge-like or dough-like consistency. This mixture is then slowly injected into the bone-filling mesh bag through the injection tube until the collapsed vertebral body is filled. Finally, after the bone cement has completely hardened, the injection tube is removed, the working channel is withdrawn, and the area is bandaged. The surgery is then complete.

[0082] Using the numerical simulation technology for bone cement bone repair and shaping provided in this example, a numerical analysis was performed on the bone cement injection, diffusion, and solidification process in patients with general osteoporotic fractures. The initial temperatures of the bone cement were set to 4℃, 20℃, and 30℃, with an initial injection pressure of 4 atm (standard atmospheric pressure), subsequently increased to 10 atm. The mesh diameter of the bone-filling mesh bag was set to 100 μm. The initial concentrations of monomers and initiators, the thermal conductivity of the bone cement, and the equivalent convective heat transfer coefficient between the bone cement and the human body were input. The heat transfer process between the bone cement and the vertebral body follows Fourier's law of heat conduction. Using current numerical simulation technology, the numerical calculation results of the monomer concentration c of the bone cement polymerization reaction at different injection temperatures (4℃, 20℃, 30℃) as a function of time t are shown below. Figure 1 As shown, the monomer concentration decreases nonlinearly with the increase of bone cement injection time, and the rate of decrease is fast at first and then slows down. Moreover, the higher the injection temperature, the higher the rate of decrease in monomer concentration, which indirectly indicates that the workable time of bone cement is extended at lower injection temperatures.

[0083] Example 2: Numerical simulation of the field evolution of the degree of polymerization reaction of bone cement

[0084] A certain model, GT-03, bone-filling mesh bag consists of a delivery device and a mesh bag. The delivery device includes an injection tube, a core needle, and a push rod. The mesh bag is made of polyethylene terephthalate (PET). Its structure features a double-layer injection tube and a single-layer mesh bag, connected by a compression joint. The mesh bag length is 25mm. The mesh bag seat and end caps are made of pure titanium TA2 conforming to GB / T13810-2007 standard. The metal parts of the injection tube, core needle, push rod, etc., are made of S30408 ​​stainless steel conforming to the requirements of M in Table 2 of YY / T 0294.1-2005 standard, and the handle is made of ABS material. The product is delivered aseptically, for single use, and is used to treat vertebral compression fractures in the lower thoracic and lumbar vertebrae caused by osteoporosis or trauma. The accompanying instruments and bone cement include a complete set of vertebral body shaping surgical instruments and polymethyl methacrylate bone cement.

[0085] This example uses SpinePlex bone cement. A 4.0mm diameter, 126mm long puncture needle was used to establish the working channel. Then, a GT-03 bone-filling mesh bag was used to inject bone cement for vertebral body filling. Subsequently, the bone cement rapidly polymerized until it was completely cured. A numerical simulation of the mesh bag formation procedure was performed on a patient with a moderate osteoporotic fracture. A series of parameters were set on the computer, such as an initial bone cement temperature of 25℃, an initial injection pressure of 4 atm (increased to 10 atm), a mesh diameter of 100μm for the bone-filling mesh bag, and monomer concentrations of 3mol / L, 5mol / L, and 6mol / L. The initial concentration of the initiator and the initial viscosity of the bone cement were input. The equivalent permeability of the bone cement was calculated, and the degree of polymerization of the bone cement was numerically simulated over time. The results are as follows: Figure 2 As shown, the degree of polymerization of bone cement increases with the increase of injection time, initially fast, then slow, and finally slows down, with the degree of polymerization approaching 100%. Moreover, the higher the monomer concentration, the faster the degree of polymerization increases in the early stage of injection.

[0086] Example 3: Numerical simulation of the change in heat release during the polymerization reaction of bone cement

[0087] A certain model, GT-0325, bone-filling mesh bag consists of a delivery device and a mesh bag. The delivery device includes an injection tube, a core needle, and a push rod. The mesh bag is made of polyethylene terephthalate (PET). Its structure features a double-layer injection tube and a single-layer mesh bag, connected by a compression joint. The mesh bag is 25mm long, with a rated capacity of 2.5mL. The injection tube diameter is 3.4mm. The mesh bag seat and end are made of pure titanium TA2 conforming to GB / T13810-2007 standard. The metal parts of the injection tube, core needle, and push rod are made of S30408 ​​stainless steel conforming to the requirements of M in Table 2 of YY / T 0294.1-2005 standard, while the handle is made of ABS material. The product is delivered sterile, for single use, and is used to treat vertebral compression fractures in the lower thoracic and lumbar vertebrae caused by osteoporosis or trauma. The accompanying instruments and bone cement include a complete set of vertebral body shaping surgical instruments and polymethyl methacrylate bone cement.

[0088] This example uses Osteopalv bone cement. A 4.0mm diameter, 120mm long puncture needle was used to establish the working channel. Then, a GT-0325 bone-filling mesh bag was used to inject bone cement for vertebral body filling. Subsequently, the bone cement rapidly polymerized until complete solidification. Numerical simulations were performed on the mesh bag formation procedure for a patient with severe osteoporotic fracture. A series of parameters were set on the computer, such as an initial bone cement temperature of 25℃, an initial injection pressure of 4 atm (later increased to 10 atm), a mesh diameter of 100μm for the bone-filling mesh bag, and monomer concentrations of 3mol / L, 5mol / L, and 6mol / L. The initial concentration of the initiator and the initial viscosity of the bone cement were input. The equivalent permeability of the bone cement was calculated, and the change in the heat release of the bone cement polymerization reaction over time was numerically simulated. The results are as follows: Figure 3 As shown, the heat generated by the polymerization reaction increases with the increase of bone cement injection time. The rate of increase is fast at first and then slows down. The higher the monomer concentration, the faster the heat generation rate in the early stage and the more heat generated.

[0089] Example 2

[0090] This embodiment provides a numerical simulation optimization system for bone repair and shaping using mesh bag-type bone cement, which specifically includes the following modules:

[0091] The parameter acquisition module is used to acquire the physical performance parameters, initial values, and boundary conditions of the mesh bag bone cement.

[0092] The numerical simulation module is used to numerically simulate the process of bone cement injection, dispersion and curing based on the bone repair and shaping mathematical model of mesh bag bone cement, and obtain the simulation results under the current bone repair and shaping mathematical model parameters.

[0093] The parameter optimization module is used to perform multi-objective optimization and sensitivity analysis of individual physical performance parameters by changing the values ​​of physical performance parameters. It determines the optimal solution of the multi-objective under the influence of multiple physical quantities and the degree of influence of the corresponding physical performance parameters on the numerical simulation process, thereby obtaining a bone repair and shaping scheme that meets the conditions for bone cement injection and diffusion effect in actual clinical applications.

[0094] In the numerical simulation module, the bone repair and shaping mathematical model includes a bone cement injection mathematical model, a bone cement dispersion mathematical model, and a bone cement curing mathematical model, which are used to numerically simulate the processes of bone cement injection, dispersion, and curing, respectively.

[0095] 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.

[0096] Example 3

[0097] 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 optimization method for bone repair and shaping using mesh bag-type bone cement as described above.

[0098] Example 4

[0099] 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 optimization method for bone repair and shaping using mesh bag bone cement as described above.

[0100] 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.

[0101] 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 optimization method for bone repair and shaping using mesh bag-type bone cement, characterized in that, include: Obtain the physical property parameters, initial values, and boundary conditions of the mesh bag bone cement; The physical properties of mesh-type bone cement include bone cement injection temperature, injection pressure, monomer concentration, degree of polymerization reaction, apparent viscosity of bone cement, polymerization reaction temperature, and chemical shrinkage rate. The bone repair and shaping mathematical model based on mesh bag bone cement numerically simulates the process of bone cement injection, dispersion and curing, and obtains the simulation results under the current bone repair and shaping mathematical model parameters. The simulation results are the numerical simulation evolution results of the three-dimensional bone cement pressure exudation flow field, bone cement viscosity field, bone cement internal stress field, bone cement thermal expansion and contraction strain field, bone cement chemical shrinkage strain field, high pressure injection flow field, high pressure injection temperature field, polymerization reaction degree field, monomer concentration field, and bone cement molecular weight and its distribution field. By changing the values ​​of physical performance parameters, performing multi-objective optimization and sensitivity analysis of individual physical performance parameters, the optimal solution for multiple objectives under the influence of multiple physical quantities and the degree of influence of corresponding physical performance parameters on the numerical simulation process are determined, thereby obtaining a bone repair and shaping scheme that meets the conditions for bone cement injection and diffusion effect in actual clinical applications.

2. The numerical simulation optimization method for bone repair and shaping using mesh-type bone cement as described in claim 1, characterized in that, The bone repair and shaping mathematical model includes a bone cement injection mathematical model, a bone cement dispersion mathematical model, and a bone cement curing mathematical model, which are used to numerically simulate the processes of bone cement injection, dispersion, and curing, respectively.

3. The numerical simulation optimization method for bone repair and shaping using mesh-type bone cement as described in claim 1 or 2, characterized in that, The numerical simulation of bone cement injection is simplified as a heat transfer and mass transport process of a three-dimensional viscous fluid transferring to the human body temperature environment at a certain set temperature.

4. The numerical simulation optimization method for bone repair and shaping using mesh-type bone cement as described in claim 1 or 2, characterized in that, The numerical simulation of bone cement dispersion is simplified to the physical seepage process of a three-dimensional viscous fluid in a porous medium.

5. The numerical simulation optimization method for bone repair and shaping using mesh-type bone cement as described in claim 1 or 2, characterized in that, The numerical simulation of bone cement solidification is simplified as a thermo-chemical-mechanical coupling process in which a three-dimensional viscous fluid containing an internal heat source undergoes a chemical reaction under certain temperature and pressure, transforming from a fluid that can be drawn into strands or dough into a solid with increased hardness and strength, and generating volume shrinkage and internal stress.

6. The numerical simulation optimization method for bone repair and shaping using mesh-bag bone cement as described in claim 1, characterized in that, By changing the values ​​of physical performance parameters, performing multi-objective optimization and sensitivity analysis of individual physical performance parameters, the dynamic evolution of physical performance parameters is used to demonstrate the bone repair and shaping process.

7. A numerical simulation optimization system for bone repair and shaping using mesh bag type bone cement, employing the numerical simulation optimization method for bone repair and shaping using mesh bag type bone cement as described in any one of claims 1-6, characterized in that, include: The parameter acquisition module is used to acquire the physical performance parameters, initial values, and boundary conditions of the mesh bag bone cement. The numerical simulation module is used to numerically simulate the process of bone cement injection, dispersion and curing based on the bone repair and shaping mathematical model of mesh bag bone cement, and obtain the simulation results under the current bone repair and shaping mathematical model parameters. The parameter optimization module is used to perform multi-objective optimization and sensitivity analysis of individual physical performance parameters by changing the values ​​of physical performance parameters. It determines the optimal solution of the multi-objective under the influence of multiple physical quantities and the degree of influence of the corresponding physical performance parameters on the numerical simulation process, thereby obtaining a bone repair and shaping scheme that meets the conditions for bone cement injection and diffusion effect in actual clinical applications.

8. The numerical simulation optimization system for bone repair and shaping using mesh-bag type bone cement as described in claim 7, characterized in that, In the numerical simulation module, the bone repair and shaping mathematical model includes a bone cement injection mathematical model, a bone cement dispersion mathematical model, and a bone cement curing mathematical model, which are used to numerically simulate the processes of bone cement injection, dispersion, and curing, respectively.

9. 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 optimization method for bone repair and shaping using mesh bag-type bone cement as described in any one of claims 1-6.

10. 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 optimization method for bone repair and shaping using mesh bag type bone cement as described in any one of claims 1-6.

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