Preparation method of interskeletal fitting type stretchable knee pressure testing gasket

Abstract

The invention relates to a preparation method of an interskeletal fitting type stretchable knee pressure testing gasket, and belongs to the field of biomechanical measurement. According to the knee pressure testing gasket, the unique paper-cut conformal design is adopted, and the shape and the notch are specially designed, so that the gasket can be flexibly stretched during installation and perfectly fit the bone contour of a patient. By means of the design, the measurement precision and reliability are greatly improved, and guarantee is provided for the success rate of an operation. The method for designing the knee pressure measuring gasket in the operation through the paper-cut (Kirgami) conformal technology is an innovative method, and the fitness and flexibility of the gasket can be improved. According to the paper-cut technology, a structure capable of being unfolded and bent is formed through precise cutting in materials, and therefore the materials can better adapt to complex shapes. And finally, preparing the interosseous fitting type stretchable knee pressure testing gasket by combining paper-cut design with femtosecond laser-induced carbonization processing.

Description

Technical Field

[0001] The invention relates to a method for preparing an interosseous fitting stretchable knee pressure testing pad, and belongs to the field of biomechanical measurement. Background Art

[0002] Total knee replacement surgery: Total knee replacement surgery (TKA) is an important means to solve the pain and dysfunction of patients with severe knee diseases. It is mainly suitable for degenerative knee lesions caused by osteoarthritis, rheumatoid arthritis or post-traumatic arthritis. This surgery significantly improves the patient's quality of life by replacing the damaged part of the knee joint surface to restore the normal function of the joint and reduce pain. At the beginning of the operation, an incision is first made in the front of the patient's knee, which is generally 8 to 10 cm long. Through this incision, the surgeon can remove the damaged joint surface, including part of the femur, tibia and patella. The doctor then implants a specially designed metal prosthesis into the end of the femur and tibia, fixed by bone cement or biosynthetic material. In some cases, the patella also needs to be replaced or reshaped. After the prosthesis is installed, the surgeon will adjust the alignment and stability of the knee joint to ensure that the new joint can work in the correct position, and then close the incision. During the adjustment period, force testing is required, which is the key to the success of the operation.

[0003] Intraoperative knee pressure measurement pad: The intraoperative knee pressure measurement pad is a specialized tool used in total knee arthroplasty (TKA) to evaluate and adjust the pressure distribution after the knee replacement prosthesis. This pad helps surgeons ensure the correct placement of the prosthesis and the uniform pressure distribution between the joint surfaces, thereby achieving optimal biomechanical performance and extending the life of the prosthesis. The intraoperative knee pressure measurement pad is usually composed of multiple sensors that can measure and display the pressure of various parts of the knee joint in real time during surgery. This data can be fed back to the surgeon in real time, and the doctor can adjust the position and orientation of the prosthesis accordingly to ensure that the force line of the joint is normal and the pressure distribution is ideal. The intraoperative knee pressure measurement pad can improve the accuracy of the operation. By feeding back the pressure data in real time, the doctor can adjust the prosthesis more accurately and increase the success rate of the operation. It can also increase the service life of the prosthesis. The correct prosthesis position and pressure distribution can reduce long-term abnormal wear or stress concentration and extend the effective use period of the prosthesis. It can also reduce postoperative complications. The uniform force distribution can reduce postoperative pain and joint function recovery period. Intraoperative knee pressure measurement spacers are a very useful tool that can significantly improve the precision and long-term success of total knee replacement surgery.

[0004] Osteo-conform intraoperative knee pressure measurement pads: They are designed to provide accurate pressure data and feedback during total knee arthroplasty (TKA) surgery to ensure the best fit between the bone and the prosthesis. The design of these pads allows them to fit the shape of the knee bone perfectly, allowing for more accurate measurement and assessment of the pressure distribution of the knee joint during surgery and after the prosthesis is fitted. This high degree of fit is achieved by using advanced biocompatible materials and a design that is customized to the specific morphology of the patient's knee joint. The pads fit perfectly to the bone, providing a more customized solution that meets individual differences, ensuring precision and personalization of the surgery. Because the pads fit the surface of the knee joint very well, it can more accurately measure the pressure at the contact point, which is critical for determining the optimal position and angle of the prosthesis. By providing a detailed pressure map, it helps surgeons adjust the prosthesis to achieve ideal alignment, which is important for preventing postoperative pain and improving the life of the prosthesis. Osteo-conform intraoperative knee pressure measurement pad technology provides a way to significantly improve the success rate of surgery and prosthesis fit for total knee replacement surgery. It is expected to improve surgical outcomes and the quality of postoperative recovery of patients by ensuring the best fit and pressure distribution between the prosthesis and the bone. Summary of the invention

[0005] The purpose of the present invention is to solve the problem of low surgical success rate caused by inaccurate measurement of knee pressure distribution in total knee replacement surgery, and to provide a method for preparing an interosseous fit stretchable knee pressure test gasket. The knee pressure test gasket of the present invention adopts a unique paper-cut conformal design, and the shape and incision are specially designed to ensure that the gasket can be flexibly stretched during installation and perfectly fit the patient's bone contour. This design greatly enhances the accuracy and reliability of the measurement, providing a guarantee for the success rate of the operation. Designing intraoperative knee pressure measurement gaskets through kirigami conformal technology is an innovative method that can improve the fit and flexibility of the gasket. Kirigami technology forms a structure that can be unfolded and bent by precise cutting in the material, so that the material can better adapt to complex shapes. Finally, the interosseous fit stretchable knee pressure test gasket is prepared by combining paper-cut design with femtosecond laser induced carbonization processing.

[0006] The purpose of the present invention is achieved through the following technical solutions.

[0007] Step 1: Build a 3D model based on the individual's knee contour scan;

[0008] Step 2: The constructed 3D model is segmented by using paper cutting technology and a segmentation pattern is designed; a laser cutting machine is used to cut the material according to the segmentation pattern; the material has good biocompatibility and elasticity;

[0009] Step 3: Laser-induced graphene pressure sensing unit and circuit

[0010] Place the cut material in step 2 on a three-dimensional movable translation stage; adjust the Z axis on the PC end, focus the laser on the sample surface through the focusing objective lens, and make it present a clear image; change the processing parameters on the PC end, and adjust the power of the laser by adjusting the angle of the attenuation plate; according to the parameters set in the above steps, process the graphene pressure sensing unit and circuit on the precursor film through the set program; finally, restore the sensing unit and circuit in 3D according to the segmentation pattern;

[0011] Beneficial effects:

[0012] Improve surgical accuracy and safety: Compared with traditional hard measuring pads and non-conformal flexible pads, the paper-cut design can provide more accurate pressure test data because it fits perfectly with the kneecap. By monitoring the pressure distribution of the knee joint in real time, doctors can adjust the position and angle of the prosthesis more accurately to ensure the best placement of the prosthesis. This precise operation helps reduce possible complications during surgery and improve the overall success rate of surgery.

[0013] Secondly, ultra-thin flexible polymer films need to overcome the temperature changes during the processing process that will cause the material to deform. Femtosecond laser processing technology has an ultra-short pulse time (10 -15 s) and ultra-high instantaneous peak power (10 14 W / cm 2 ), and exhibits strong nonlinear and non-equilibrium characteristics in the process of interaction with materials. When processing ultra-thin flexible films, the thermal effect is low, which greatly improves the manufacturing accuracy and can achieve cross-scale manufacturing from nanometers to meters. It has little impact on the material and avoids the damage to the material caused by temperature changes in traditional processing methods. The laser-induced carbonization method is simple, fast and environmentally friendly. At the same time, it can realize the preparation of materials with different functions based on local block doping, which provides a feasible method for the integrated manufacturing of multifunctional flexible microsystems. Through femtosecond laser ablation, stripping, doping and functionalization, the electrical conductivity, thermal conductivity, mechanical and physical and chemical properties of graphene are regulated to achieve integrated manufacturing of flexible multifunctional microsystems. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 To obtain detailed three-dimensional images of the patient’s knee;

[0015] Figure 2 To design paper cutting patterns;

[0016] Figure 3 Cut for laser cutting machine;

[0017] Figure 4 Laser-induced graphene pressure sensing unit and circuit. DETAILED DESCRIPTION

[0018] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0019] Example 1

[0020] Step 1: Obtain a detailed 3D image of the patient’s knee

[0021] like Figure 1 To ensure that a detailed 3D image of the patient's knee is obtained, the following specific plan can be implemented:

[0022] ① Generally speaking, MRI (magnetic resonance imaging) and CT (computed tomography) are the two most common technologies for obtaining detailed three-dimensional images of joints. The appropriate imaging technology is selected according to the patient's specific situation and surgical requirements.

[0023] ② Determine the imaging parameters and communicate with radiologists and technicians to ensure that the imaging parameter settings are most suitable for capturing the three-dimensional structure of the knee joint, including resolution, contrast, and the specific range of the scan, etc.

[0024] ③ Before the scan, you need to make sure the patient understands the process and takes the appropriate posture. For knee scans, the patient usually needs to lie flat, and the knee may need to be fixed to prevent movement, which will affect the image quality.

[0025] ④ During the scan, the patient should remain still under guidance and complete the entire scanning process. Depending on the equipment and technology used, the scan may last from a few minutes to half an hour.

[0026] ⑤ Image post-processing: the raw data obtained by scanning needs to be post-processed by professional software, including image reconstruction, filtering and enhancement, so as to improve the image quality and make it more suitable for subsequent design analysis.

[0027] ⑥Convert to a 3D model, using medical image processing software to convert the 2D images into a 3D model. Software such as Mimics or Simpleware can process these images and convert them into a 3D model (such as STL format) that can be further used for engineering analysis and design.

[0028] ⑦ Verify and adjust the model. Before designing and manufacturing the gasket, work closely with the clinician to check the 3D model to ensure that it accurately reflects the patient's anatomy. Make adjustments if necessary to ensure the accuracy of the model.

[0029] Through the above steps, the three-dimensional image of the patient's knee can be acquired and processed more accurately, providing the necessary basic data for making personalized paper-cut gaskets.

[0030] Step 2: Design the paper-cutting pattern

[0031] like Figure 2 ① With the help of the simulation unfolding module of the 3D software (such as the Analyze Formability-One-Step Unfolding command of the UG software) or MATLAB programming, the plane unfolding of the detailed 3D image of the knee is completed to obtain the plane segmentation piece. ② In the software, a preliminary paper-cut design is created based on the 3D data of the knee, and the shape and function of the gasket are optimized by simulating different cutting modes and layouts.

[0032] Step 3: Cutting

[0033] like Figure 3 , cut using a laser cutter. ① Material selection: Select appropriate materials. As mentioned above, these materials need to have good biocompatibility and elasticity. Here, polyimide is selected, and then encapsulated with PDMS.

[0034] ② Application of cutting technology: Use precision laser cutting machines to cut the material according to the design pattern. Ensure cutting accuracy to maintain the functionality and aesthetics of the design.

[0035] Step 4: Laser-induced graphene pressure sensing unit and circuit

[0036] like Figure 4 , place the cut polyimide film on a three-dimensional movable translation stage. Adjust the Z axis on the PC side, and focus the laser on the sample surface through the focusing objective lens to present a clear image. Change the parameters on the PC side, set the laser repetition frequency to 1MHz, and select 20X for the focusing objective lens for processing. Adjust the power of the laser by adjusting the angle of the attenuation plate, and the power range is 300-600MW. Set the parameters according to the above steps, and process the graphene pressure sensor unit and circuit on the precursor film through the set program.

[0037] During the laser direct writing process on the surface of the carbon-rich precursor, the chemical bonds in the precursor will be broken, releasing gas, thus forming a layered porous LIG structure and realizing the preparation of various functional units. The formation mechanism of LIG is mainly the photochemical effect and photothermal effect of the laser.

[0038] Step 5: Packaging

[0039] After the conductivity test, we use medical materials for encapsulation. PDMS can be used to cover the surface where passivation is required. Prepare PDMS precursor and cross-linking agent, mix them in a specific ratio, and mix the mixture thoroughly with a stirrer until a uniform PDMS solution is obtained. Pour the PDMS solution on the surface of the paper-cut gasket, and apply PDMS to the required thickness with a scraper or roller. The thickness of PDMS can be controlled by adjusting the height of the scraper or roller. It should be noted here that it can be done under some measurement methods, and the thickness is kept at the level of hundreds of microns as much as possible. The graphene device coated with PDMS is placed in a vacuum to remove bubbles. The sample is placed on a hot plate and the PDMS is cured at a certain temperature. The curing temperature and time depend on the PDMS formula used. Once the PDMS is cured, the PDMS layer can be gently peeled off from the substrate. Finally, the encapsulation layer is completely peeled off, and the encapsulated graphene device is not damaged. At the same time, encapsulating a layer of PDMS increases the flexibility of the sensor and makes the sensor suitable for more special scenarios due to its smooth surface and waterproof properties.

[0040] In summary, the present invention relates to an interosseous fit-type stretchable knee pressure test gasket based on paper-cut conformal design. The point that needs to be protected is that we apply the paper-cut conformal design to the intraoperative knee pressure measurement gasket. Compared with the traditional pressure gasket, the special design method will make the measurement more accurate and improve the surgical effect of the patient. In addition, the paper-cut conformal gasket can be ultra-thin, flexible and retractable, and greatly reduces the cost. This is a major breakthrough in the design and manufacture of intraoperative knee pressure measurement gaskets.

[0041] The specific description above further illustrates the purpose, technical solutions and beneficial effects of the invention in detail. It should be understood that the above is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing an interosseous fit stretchable knee pressure test pad, characterized in that: The following steps are included: Step 1: Build a 3D model based on the individual's knee contour scan; Step 2: The constructed 3D model is segmented by using paper cutting technology and a segmentation pattern is designed; a laser cutting machine is used to cut the material according to the segmentation pattern; the material has good biocompatibility and elasticity; Step 3: Laser-induced graphene pressure sensing unit and circuit Place the material cut in step 2 on a three-dimensional movable translation stage; adjust the Z axis on the PC side, focus the laser onto the sample surface through the focusing objective lens, and present a clear image; change the processing parameters on the PC side, and adjust the power of the laser by adjusting the angle of the attenuation plate; according to the parameters set in the above steps, process the graphene pressure sensing unit and circuit on the precursor film through the set program; finally, restore the sensing unit and circuit in 3D according to the segmentation pattern.

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