Lightweight simulated bone model and preparation method thereof

Abstract

The invention discloses a lightweight simulation bone model and a preparation method thereof. The lightweight simulation bone model is prepared by mixing and foaming a polyurethane hard foaming material and epoxy resin glue, and the weight ratio of the polyurethane hard foaming material to the epoxy resin glue is (8-25): 1. The lightweight simulation bone model is provided with a cortical bone and a cancellous bone which are in rigidity gradient change from outside to inside, the surface hardness of the cortical bone is larger than or equal to 4, and the core hardness of the cancellous bone is smaller than or equal to 3. The epoxy resin glue is added into the polyurethane foam material, and the preparation method is improved, so that the flowability of a raw material mixed solution is better, the simulated bone model with rigidity gradient change from outside to inside is formed, the hardness, rigidity and toughness of the simulated bone model are remarkably improved, and the simulated bone model has a good application prospect. Real bones of people or animals can be more effectively simulated, the repeated utilization rate is high, and dry-type practical operation of clinicians is facilitated. The cost is greatly reduced, and popularization and use are facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of simulated bone models, and in particular to a lightweight simulated bone model and a preparation method thereof. Background Art

[0002] In the orthopedic field of medical devices, doctors need strict training before they can go to the operating table to treat patients or pets. Therefore, doctors must not only receive theoretical knowledge training, but also need to practice hands-on operation to learn the use skills and precautions of various instruments. In the process of practical operation, in order to let doctors feel the real surgical scene, training institutions, hospitals or schools need a large number of simulated bone models to replace real bones and help doctors perform surgical simulation operations. Such a training process is called dry practice. In dry practice, the simulated bone model should simulate the various properties of real bones to the maximum extent, including elastic modulus, weight, stiffness gradient, etc. Specifically: the surface hardness of the simulated bone model must be hard to simulate the high hardness and high strength of cortical bone; the whole of the simulated bone model must have high stiffness and not easy to deform; the whole of the simulated bone model must have high toughness, not easy to break, and have strong support capacity; the whole of the simulated bone model must be light and not too heavy; it must also be easy to cut. On this basis, polyurethane foam materials are basically used to manufacture simulated bone models in the current industry.

[0003] At present, there are many such simulated bone models on the market. The most famous manufacturer is sawbones, which has become synonymous with simulated bones. However, during the actual research and development process, the applicant found that sawbones' products still have the following problems: (1) The rigidity and hardness of the cortical bone of simulated bones are less than that of real bones, and it is obviously much easier to cut and drill than real bones. In simple terms, the surface hardness is not enough; (2) There is no gradient change in stiffness when the simulated bone is viewed from the cross section. The internal cancellous bone is filled with pink foam, and the hardness and strength are not enough. The main manifestation is that it is not easy to fix various orthopedic instruments, and the reuse rate is low. In dry practice, the holding force of the screws is poor and the fixing depth is not enough. (3) The sawbones product model is expensive. Pet bone models are generally more than 30 yuan per root, and human bone models are generally more than 100 yuan per root, making the training cost too high.

[0004] It can be seen that the above existing simulated bone models still have inconveniences and defects in structure, method and use, and are in urgent need of further improvement. How to create a new lightweight simulated bone model and its preparation method, so that it can improve the surface hardness of the simulated bone model, meet the requirements of the stiffness gradient change from the outside to the inside of the simulated bone model, and greatly reduce the cost to meet market demand, has become a goal that the industry needs to improve. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a lightweight simulated bone model, which can improve the surface hardness of the simulated bone model, meet the stiffness gradient change requirement from the outside to the inside of the simulated bone model, and greatly reduce the cost to meet market demand, thereby overcoming the shortcomings of the existing simulated bone model.

[0006] In order to solve the above technical problems, the present invention provides a lightweight simulated bone model, which is made by mixing and foaming a polyurethane rigid foam material and an epoxy resin glue, wherein the weight ratio of the polyurethane rigid foam material to the epoxy resin glue is 8~25:1.

[0007] Further improvement, the weight ratio of the polyurethane rigid foam material to the epoxy resin glue is 10:1.

[0008] As a further improvement, the polyurethane rigid foam material is formed by mixing polyester polyol and isocyanate in a ratio of 1:1, and the epoxy resin glue is formed by mixing epoxy resin glue component a and epoxy resin glue component b in a ratio of 3:1.

[0009] Further improvement, the lightweight simulated bone model has cortical bone and cancellous bone with a gradient stiffness change from the outside to the inside, wherein the surface hardness of the cortical bone is greater than or equal to 4, and the maximum Mohs hardness can reach 6, and the core hardness of the cancellous bone is less than or equal to 3. The Mohs hardness of real bones is generally between 4 and 5. Therefore, the simulated bone model can more realistically simulate real bones, and can also simulate the condition of patients with osteosclerosis.

[0010] According to a further improvement, the simulated bone model is any one of the humerus, ulna, radius, femur, tibia, fibula, patella, pelvis, and spine of a human or animal.

[0011] As another improvement of the present invention, the present invention also provides a method for preparing the above-mentioned lightweight simulated bone model, comprising the following steps:

[0012] (1) Mixing a polyurethane rigid foam material and an epoxy resin glue according to a weight ratio, and quickly pouring the mixed liquid into a mold of a simulated bone model, wherein the mixed liquid is coated with the inner wall of the mold under the rotation and swing of the mold, and this step is completed within 15 to 60 seconds;

[0013] The purpose of swinging the mold in this step is to ensure that there is mixed liquid material at the head and bottom of the mold (i.e., the proximal and distal ends of the injection port); the purpose of rotating the mold is to ensure that the side walls of the mold are covered with mixed liquid material. In specific operations, you can shake first and then rotate, or rotate first and then shake, or shake and rotate simultaneously. After this step is completed, the foaming direction of the mixed liquid material grows from the top and bottom and the surroundings to the inside, so as to produce a product with a stiffness gradient distribution, that is, high surface density, high strength and high hardness, low internal density, low hardness and low strength.

[0014] (2) Waiting for the mixed liquid in the mold to foam from the periphery to the center until the foaming liquid overflows from the pouring port, the mold is placed in a constant temperature environment of 30±10°C to gradually cool and harden;

[0015] (3) Disassembling the mold to obtain the lightweight simulated bone model.

[0016] Further improvement, in step (1), the polyurethane rigid foam material and the epoxy resin glue are mixed in an environment with a temperature of 20±10°C and a humidity of ≤70%, and the mixing time of the mixed liquid before being poured into the mold is controlled within 15s. The more optimal environmental requirements are: temperature 20±2°C, humidity below 50%. If the temperature is too high, the raw materials are prone to deterioration, precipitation is generated, affecting the performance, resulting in reduced strength and stiffness; if the temperature is too low, the reaction between the components will be too slow, the product molding time will be too long, and thus the production efficiency will be affected.

[0017] As a further improvement, the pouring port of the mold in step (1) is located at the center of one end of the mold, and the mold completes 3 to 20 axial rotations and 3 to 20 back and forth swings before the mixed liquid foams. Preferably, the mold rotates 10 times axially and swings 10 times back and forth. Since the polyurethane foam material undergoes a basic process of viscosity → dilution → viscosity → hardening during the foaming process after stirring. In this process, if it rotates at a high speed, the material will be centrifuged, resulting in slower foaming or no foaming, which will also affect the foaming effect. Rotating too slowly will cause the material to foam quickly, and a good stiffness gradient effect will not appear. Therefore, the rotation of the mold in this step adopts a low-frequency rotation method.

[0018] Further improvement, in step (2), the mold is gradually cooled and hardened in a constant temperature environment of 30±5°C. If the temperature is too high, it is not easy to operate the mold, and the reaction will be too fast, resulting in defects such as pores in the product; if the temperature is too low, the performance of the product will be reduced, and the hardness and strength levels will not meet the requirements.

[0019] As a further improvement, the mold is made of metal material or polymer material, and the polymer material is silicone with a hardness of 15 to 65 degrees.

[0020] After adopting such a design, the present invention has at least the following advantages:

[0021] 1. The lightweight simulation bone model of the present invention makes the raw material mixture more fluid by adding epoxy resin glue to the polyurethane foam material, which can more effectively improve the hardness, rigidity and toughness of the simulation bone model. Compared with the existing simulation bone model, not only the hardness of its surface is improved, but also the stiffness gradient changes from the outside to the inside, the surface hardness is higher, the layering effect is better, and the holding force of the bone nail on the simulation bone model can be greatly increased, the reuse rate of the simulation bone model is improved, and the real bones of humans or animals are more effectively imitated, which is beneficial to the dry operation of clinicians. And the price is also greatly reduced, such as the simulation bone model prepared by the present application is at least 50% lower than the price of the existing simulation bone model.

[0022] 2. The preparation method of the lightweight simulation bone model of the present invention is based on changing the principle formula of the simulation bone model. Through precise control of the preparation method, the mold can be fully mixed and stained with the inner wall of the mold before the raw material mixture is foamed, so that the foaming direction of the raw material mixture grows from the top and bottom and all around the mold to the inside, thereby producing a lightweight simulation bone model with high surface density, high strength, high hardness, low internal density, low hardness, and low strength, showing a stiffness gradient change. The lightweight simulation bone model has obvious surface cortical bone and internal cancellous bone, and the surface hardness of the cortical bone is greater than or equal to 4, and the hardness of the cancellous bone core is less than or equal to 3, which conforms to the hardness gradient distribution of real bones of humans or animals, is conducive to dry practical training, and meets the requirements of multiple uses, greatly reducing training costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0024] Figure 1 It is a schematic diagram of the structure of the pet humerus product prepared in Example 1 of the present invention.

[0025] Figure 2 It is a schematic diagram of the cross-sectional structure of the pet humerus product prepared in Example 1 of the present invention.

[0026] Figure 3 It is a schematic diagram of the structure of the pet radius product prepared in Example 2 of the present invention.

[0027] Figure 4 It is a schematic diagram of the structure of the pet radius product prepared in Example 3 of the present invention.

[0028] Figure 5 It is a schematic diagram of the structure of the pet simulation bone model product prepared in Example 4 of the present invention.

[0029] Figure 6 It is a schematic diagram of the structure of the human simulated bone model product prepared in Example 4 of the present invention. DETAILED DESCRIPTION

[0030] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0031] Example 1

[0032] Taking the pet's humerus model as an example, the specific production process is as follows:

[0033] (1) Weigh 20 g of polyester polyol, 20 g of isocyanate, 3 g of two-component epoxy resin adhesive component A, and 1 g of two-component epoxy resin adhesive component B respectively.

[0034] (2) First, mix the resin glue components A and B, and then mix them with isocyanate and polyester polyol in sequence, and stir evenly. The stirring time is controlled within 15 seconds, and the mixed liquid is quickly poured into the silicone mold of the humerus. After the pouring is completed, the mold is shaken back and forth and rotated axially so that the mixed liquid contacts all positions of the mold cavity, and then wait for foaming to begin.

[0035] In this embodiment, the mold can be shaken back and forth and rotated axially by hand or by a low-frequency centrifugal shaking tool. It should be noted that this step, from the mixing of the raw materials to the inner wall of the mold being covered with the mixed liquid, is preferably completed within 40 seconds, and the mold needs to be shaken back and forth 10 times and rotated axially 10 times.

[0036] The mold described in this embodiment is made of polymer materials, such as a silicone mold. The silicone mold described in this embodiment is made of single-component silicone, wherein the mass ratio of the silicone body to the curing agent is 100:1. Of course, the silicone mold can also be made of two-component silicone, as long as it can meet the requirements of the injection, mixing, and foaming of the mixed liquid of the simulated bone model raw materials. In addition, the mold can also be made of metal materials.

[0037] (3) Wait for the mixed liquid to start foaming in the mold until the foaming liquid overflows from the injection port, and then place the mold in a constant temperature environment of 30±5°C to gradually cool and harden.

[0038] (4) Disassemble the mold, take out the product, and remove the process end, flash and other residues of the simulated bone model to obtain the lightweight simulated humerus model 1, as shown in the attached Figure 1 shown.

[0039] Attached Figure 2 FIG. 1 shows a cross-sectional structural view of the lightweight simulated humeral model 1. Figure 2 It can be seen that the cross-sectional structure of the simulated humerus model 1 has obvious surface cortical bone 11 and cancellous bone 12 located inside the cortical bone 11 .

[0040] This embodiment also tests the Mohs hardness of the lightweight simulated humerus model 1 by a scratch hardness test method, and the results are as follows: the Mohs hardness of the surface cortical bone of the lightweight simulated humerus model 1 is 5, which is consistent with or harder than the Mohs hardness of real human bones (between 4 and 5), and much greater than the surface hardness of traditional existing bone models (between 2.5 and 3.5); the Mohs hardness of the internal transition cancellous bone of the lightweight simulated humerus model 1 is 3, and the Mohs hardness of the core cancellous bone is 2, showing a gradient change in stiffness, and the hardness is getting smaller and smaller, which is in line with the bone characteristics of humans or animals. In addition, the lightweight simulated humerus model 1 has high rigidity and good toughness, which can meet the requirements of dry practice in clinical teaching.

[0041] Example 2

[0042] Taking the pet radius model as an example, the specific production process is as follows:

[0043] (1) Weigh 13.5 g of polyester polyol, 13.5 g of isocyanate, 2.025 g of two-component epoxy resin adhesive component A, and 0.675 g of two-component epoxy resin adhesive component B, respectively.

[0044] (2) First, mix the resin glue component A and component B, then mix them with isocyanate and polyester polyol in sequence, and stir them evenly. The stirring time is controlled within 15 seconds, and the mixed liquid is quickly poured into the silicone mold of the radius. After the pouring is completed, the mold is shaken back and forth and axially rotated so that the mixed liquid contacts all positions of the mold cavity, and then wait for the foaming to start;

[0045] Similarly, the forward and backward shaking and axial rotation of the mold can be done manually or by a low-frequency centrifugal shaking tool. This step starts from the mixing of the raw materials until the inner wall of the mold is covered with the mixed liquid, and is preferably completed within 40 seconds. The mold needs to be shaken forward and backward 10 times and rotated 10 times.

[0046] (3) The mixed liquid begins to foam in the mold until the foaming liquid overflows from the injection port, and then the mold is placed in a constant temperature environment of 30±5°C to gradually cool and harden.

[0047] (4) Disassemble the mold, take out the product, and remove the process end, flash and other residues of the simulated bone model to obtain the lightweight simulated radius model 2, as shown in the attached Figure 3 shown.

[0048] This embodiment also uses the scratch hardness test method to test the Mohs hardness of the surface of the lightweight simulated radius model 2. The results show that the Mohs hardness of the surface cortical bone of the lightweight simulated radius model 2 is greater than 3. In addition, the lightweight simulated radius model 2 has high rigidity and good toughness, which can meet the requirements of dry practice in clinical teaching.

[0049] Example 3

[0050] Still taking the pet radius model as an example, the specific production process is as follows:

[0051] (1) Weigh 13.5 g of polyester polyol and 13.5 g of isocyanate respectively.

[0052] (2) Mix the isocyanate and the polyester polyol and stir them evenly. The stirring time is controlled within 15 seconds. The mixed liquid is quickly poured into the silicone mold of the radius. After the pouring is completed, the mold is shaken back and forth and axially rotated so that the mixed liquid contacts all positions of the inner cavity of the mold, and then wait for the foaming to start;

[0053] Similarly, the forward and backward shaking and axial rotation of the mold can be done manually or by a low-frequency centrifugal shaking tool. This step starts from the mixing of the raw materials until the inner wall of the mold is covered with the mixed liquid, and is preferably completed within 40 seconds. The mold needs to be shaken forward and backward 10 times and rotated 10 times.

[0054] (3) The mixed liquid begins to foam in the mold until the foaming liquid overflows from the injection port, and then the mold is placed in a constant temperature environment of 30±5°C to gradually cool and harden.

[0055] (4) Disassemble the mold, take out the product, and remove the process end, flash and other residues of the simulated bone model to obtain the lightweight simulated radius model 3.

[0056] This embodiment also adopts the scratch hardness test method to test the Mohs hardness of the surface of the lightweight simulated radius model 3. The result shows that the Mohs hardness of the surface cortical bone of the lightweight simulated radius model 3 is less than 3.

[0057] The lightweight simulated radius model 3 was also tested for rigidity and found to be very easy to break. Figure 4 As shown, the cross section is flat, indicating that the lightweight simulated radius model 3 has low rigidity and poor toughness, is easy to break, and cannot meet the requirements of dry practice in clinical teaching.

[0058] Example 4

[0059] The present application also studies the raw material formulas of other simulated bone models and obtains the following simulated bone model formula list 1.

[0060] Table 1 Summary of formulas of various simulated bone models (g)

[0061] type Two-component epoxy resin glue A Two-component epoxy resin glue B Polyester polyols Isocyanate Pet normal femur 2.25 0.75 15 15 Pet Deformed Femur 2.25 0.75 15 15 Pet small normal femur 2.025 0.675 13.5 13.5 Pet Large Normal Femur 3 1 20 20 Pet Shin Bone 2.25 0.75 15 15 Pet tibia deformity 2.025 0.675 13.5 13.5 Pet Big Shin 3 1 20 20 Pet small ulna 1.05 0.35 7 7 Pet small radius 1.2 0.4 8 8 Pet pelvis 6 2 40 40 Human femur 16.2 5.4 108 108 Human tibia 12.75 4.25 85 85 Human humerus 10.5 3.5 70 70 Human ulna 4.5 1.5 30 30 Human radius 4.8 1.6 32 32 Human pelvis 29.25 9.75 195 195

[0062] According to the raw material formula described in Table 1 above, different simulated bone models were prepared according to the preparation method of Example 1. Figure 5 The various pet simulation bone models prepared are shown in FIG. Figure 6 Various human simulated bone models prepared are shown. Moreover, the simulated bone models obtained all have the characteristics of high surface cortical bone density, high strength, high hardness, and low internal cancellous bone density, low hardness, and low strength, which can meet the use requirements of dry practice in clinical teaching.

[0063] The simulated bone model produced by the present invention greatly reduces the production cost, so that the cost of pet bone models is reduced from about 30 yuan per piece to 10 yuan per piece, and the cost of human simulated bone models is reduced from 100 yuan per piece to 30 yuan per piece. The simulated bone model has a high reuse rate and greatly meets market demand.

[0064] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Those skilled in the art may make some simple modifications, equivalent changes or modifications using the technical contents disclosed above, which all fall within the protection scope of the present invention.

Claims

1. A lightweight simulated bone model, characterized in that: The polyurethane rigid foam material is mixed with epoxy resin glue and then foamed, wherein the weight ratio of the polyurethane rigid foam material to the epoxy resin glue is 8-25:

1.

2. The lightweight simulated bone model according to claim 1, characterized in that: The weight ratio of the polyurethane rigid foam material to the epoxy resin adhesive is 10:

1.

3. The lightweight simulated bone model according to claim 2, characterized in that: The polyurethane rigid foam material is formed by mixing polyester polyol and isocyanate in a ratio of 1:1, and the epoxy resin glue is formed by mixing epoxy resin glue component a and epoxy resin glue component b in a ratio of 3:

1.

4. The lightweight simulated bone model according to claim 3, characterized in that: The lightweight simulated bone model comprises cortical bone and cancellous bone with a gradient stiffness change from outside to inside, wherein the surface hardness of the cortical bone is greater than or equal to 4, and the core hardness of the cancellous bone is less than or equal to 3.

5. The lightweight simulated bone model according to claim 4, characterized in that: The simulated bone model is any one of the humerus, ulna, radius, femur, tibia, fibula, patella, pelvis, and spine of a human or animal.

6. The method for preparing a lightweight simulated bone model according to any one of claims 1 to 5, characterized in that: The steps include: (1) Mixing a polyurethane rigid foam material and an epoxy resin glue according to a weight ratio, and quickly pouring the mixed liquid into a mold of a simulated bone model, wherein the mixed liquid is coated with the inner wall of the mold under the rotation and swing of the mold, and this step is completed within 15 to 60 seconds; (2) Waiting for the mixed liquid in the mold to foam from the periphery to the center until the foaming liquid overflows from the pouring port, the mold is placed in a constant temperature environment of 30±10°C to gradually cool and harden; (3) Disassembling the mold to obtain the lightweight simulated bone model.

7. The method for preparing a lightweight simulated bone model according to claim 6, characterized in that: In step (1), the polyurethane rigid foam material and the epoxy resin glue are mixed in an environment with a temperature of 20±10° C. and a humidity of ≤70%, and the mixing time of the mixed liquid before being poured into the mold is controlled within 15 seconds.

8. The method for preparing a lightweight simulated bone model according to claim 7, characterized in that: In step (1), the pouring port of the mold is located at the center of one end of the mold, and the mold completes 3 to 20 axial rotations and 3 to 20 front and rear swings before the mixed liquid foams.

9. The method for preparing a lightweight simulated bone model according to claim 8, characterized in that: The mold in step (2) is gradually cooled and hardened in a constant temperature environment of 30±5°C.

10. The method for preparing a lightweight simulated bone model according to claim 6, characterized in that: The mold is made of metal material or polymer material, and the polymer material is silicone with a hardness of 15 to 65 degrees.

Images