A pekk craniofacial patch

Abstract

The application discloses a PEKK craniofacial patch and relates to the technical field of medical devices. The patch not only avoids the interference of medical images and bone loss caused by stress shielding, but also improves biocompatibility and realizes multifunctional integration. The patch comprises an outer soft tissue attachment layer, an intermediate layer and an inner bone bonding layer arranged in sequence from outside to inside. The surface of the outer soft tissue attachment layer is provided with a leaf vein type hierarchical micro-nano structure. The leaf vein type hierarchical micro-nano structure comprises a micron-level leaf vein network and a nanometer-level microstructure arranged in the gap of the micron-level leaf vein network. The micron-level leaf vein network comprises a plurality of main leaf veins connected to form a leaf vein network. Each main leaf vein is connected with a plurality of side leaf veins. Each side leaf vein is connected with a plurality of small leaf veins. The nanometer-level microstructure is a nanometer column. The inner bone bonding layer is a porous structure. The outer soft tissue attachment layer, the intermediate layer and the inner bone bonding layer are all made of PEKK material.

Description

Technical Field

[0001] This application relates to the field of medical device technology, and in particular to a PEKK craniofacial patch. Background Technology

[0002] Bone defects are a common medical problem, and artificial bone replacement has become the mainstream treatment. Currently, PEKK craniofacial patches mostly use titanium alloys, but they have drawbacks such as thermodynamic property mismatch, stress shielding effect, and imaging interference. For example, the elastic modulus of titanium alloys (100~120GPa) is much higher than that of cortical bone (10~30GPa), which easily leads to bone resorption; at the same time, titanium alloys produce artifacts in CT or MRI examinations, affecting postoperative follow-up. Inert polymers such as polyetheretherketone (PEEK), although imaging-friendly, have insufficient osteogenic activity and delayed osseointegration.

[0003] Polyetherketoneketone (PEKK), as a polymer material, has highly symmetrical and chemically inert molecules with a lack of active sites on its surface. After implantation, it easily forms fibrous encapsulation at the bone-mesh interface, hindering bone ingrowth. Furthermore, existing surface modifications are mostly single-scale, single-function solutions, either focusing on strong integration on the bone side or attempting to improve blood supply to the lateral soft tissue, making it difficult to achieve optimal biological response simultaneously at the bone-mesh-soft tissue three-dimensional interface. While coating strategies can introduce active layers such as hydroxyapatite and bioactive glass, they suffer from drawbacks such as low bonding strength, easy peeling, complex processes, and large batch-to-batch variations, resulting in insufficient long-term implantation reliability. Therefore, a new PEKK patch structure is urgently needed to improve biocompatibility and achieve multifunctional integration. Utility Model Content

[0004] The embodiments of this application provide a PEKK craniofacial patch that not only avoids interference from medical images and bone loss caused by stress shielding, but also improves biocompatibility and achieves multifunctional integration.

[0005] To achieve the above objectives, embodiments of this application provide a PEKK craniofacial patch, comprising a lateral soft tissue attachment layer, a middle layer, and a medial bone-bonding layer arranged sequentially from the outside to the inside; the surface of the lateral soft tissue attachment layer is provided with a leaf vein-like hierarchical micro / nanostructure; the leaf vein-like hierarchical micro / nanostructure includes a micron-level leaf vein network and nanoscale microstructures disposed within the gaps of the micron-level leaf vein network; the micron-level leaf vein network includes multiple main leaf veins connecting to form the leaf vein-like network; multiple lateral leaf veins are connected to each main leaf vein; multiple small leaf veins are connected to each lateral leaf vein; the nanoscale microstructure is a nanopillar; the medial bone-bonding layer is a porous structure; the lateral soft tissue attachment layer, the middle layer, and the medial bone-bonding layer are all made of PEKK material.

[0006] Furthermore, the angle between the direction of the main vein and the target blood supply axis is less than 30°, and the distance between two adjacent main veins is 2~3μm.

[0007] Further, the length of the main vein is 0.6 to 0.8 times the longest side length of the patch, the width is 2 to 4 μm, and the depth is 1 to 5 μm; the length of the lateral veins is 0.2 to 0.5 times the length of the main vein, the width is 1 to 2 μm, and the depth is 0.5 to 3 μm; the distance between two adjacent lateral veins is 300 to 500 μm; the length of the small veins is 100 to 130 μm, the width is 0.5 to 1 μm, and the depth is 0.2 to 1 μm; the distance between two adjacent small veins is 1 to 3 μm; the angle between the main vein and the lateral veins is 30° to 60°, and the angle between the lateral veins and the small veins is 30° to 60°.

[0008] Furthermore, the diameter of the nanopillar is 100~200nm; the height is 100~500nm; and the spacing between two adjacent nanopillars is 100~300nm.

[0009] Furthermore, the outer soft tissue attachment layer, the middle layer, and the inner bone bonding layer are integrally formed by 3D printing.

[0010] Furthermore, the porous structure has a pore size of 100~600 μm, a porosity of 20%~70%, and a bone-side penetration rate of ≥10%; the porous structure is composed of a single unit cell; the unit cell structure is one of gyriod, diamond, lidinoid, or splitp unit cell structures.

[0011] Furthermore, the PEKK craniofacial patch has multiple through holes that sequentially penetrate the outer soft tissue attachment layer, the middle layer, and the inner bone bonding layer along the thickness direction, allowing for the flow of tissue fluid and the exchange of substances; the diameter of the through holes is on the order of millimeters, and the porosity is greater than or equal to 10%.

[0012] Furthermore, the surface of the outer soft tissue attachment layer is roughened by sandblasting, and its surface roughness Ra is 3~20μm.

[0013] This application has the following advantages over the prior art: 1. The PEKK craniofacial patch in this application uses PEKK material. Compared with titanium alloy, PEKK material not only has good mechanical properties and easy processing characteristics, but also avoids interference from medical imaging and bone loss problems caused by stress shielding.

[0014] 2. The PEKK craniofacial patch in this application increases the surface roughness by processing a leaf vein-like hierarchical micro-nano structure on the surface of the outer soft tissue attachment layer, thereby compensating for the poor biocompatibility of PEKK.

[0015] 3. The PEKK craniofacial patch in this application achieves differentiated design for the bone side and soft tissue side by setting an outer soft tissue attachment layer, an intermediate layer, and an inner bone integration layer. Among them, the porous structure of the inner bone integration layer can play a synergistic role in good mechanical interlocking, cell-scale guidance, and tissue fluid flow, significantly improving the quality and stability of bone integration. At the same time, the nanopillar structure on the surface of the outer soft tissue attachment layer can provide sites for the adhesion and ingrowth of tissue cells. In addition, its sharp nanostructure can physically pierce the bacterial cell membrane, thereby achieving physical antibacterial function. The direction of the fibrous structure of the leaf veins can also guide blood vessels and cells to grow in a specified direction.

[0016] 4. The PEKK craniofacial patch of this application can simulate the mechanical characteristics of ECM, including roughness, porosity and fibrous structure. It utilizes the cell's own signals to promote the ingrowth of vascular endothelial cells and osteoblasts, thus endogenously improving biocompatibility. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a front view of the PEKK craniofacial patch according to an embodiment of this application; Figure 2 for Figure 1 A magnified view of a section at point I; Figure 3 for Figure 2 Enlarged view of a section at point II; Figure 4 This is a schematic diagram of the three-dimensional structure of the nanopillar; Figure 5 for Figure 1 AA section view; Figure 6 for Figure 5 Enlarged view of a section at point III; Figure 7 This is a top view of the PEKK craniofacial patch according to an embodiment of this application; Figure 8 This is a diagram showing the position of the PEKK craniofacial patch relative to the mandible and skin after it has been installed in the human body, according to an embodiment of this application. Figure 9 This is a diagram of the gyriod unit cell structure in the PEKK craniofacial patch of this application. Figure 10This is a diagram of the diamond cell structure in the PEKK craniofacial patch of this application. Figure 11 This is a diagram of the lidinoid unit cell structure in the PEKK craniofacial patch of this application. Figure 12 This is a diagram of the splitp unit cell structure in the PEKK craniofacial patch of this application. Figure 13 This is a flowchart illustrating the PEKK craniofacial patch processing method according to an embodiment of this application. Detailed Implementation

[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0021] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation", "connection" and "joining" should be interpreted broadly, for example, they can refer to fixed connections, detachable connections, or integral connections; those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0022] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" can explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0023] This application's PEKK craniofacial patch employs a zoned-graded approach. On the outer side, closer to the tissue, a leaf-vein-like graded micro / nanostructure is incorporated, including a micron-scale network (main vein, lateral veins, and microvein) and nanopillars. The purpose is to guide cell proliferation, angiogenesis, and inhibit bacterial growth, respectively, while simultaneously altering the surface roughness of this side to create conditions for cell attachment and further enhance biocompatibility. On the inner side, near the bone tissue, a porous structure is created to promote bone ingrowth while simultaneously achieving mechanical locking. Through-holes are incorporated along the thickness direction of the patch to facilitate tissue fluid return and nutrient exchange. This combination of porous structure and through-holes significantly improves bone integration quality and stability, achieving multifunctional integration. Furthermore, the roughened surface, leaf-vein network, and porous structure mimic the mechanical characteristics of the extracellular matrix (ECM) to some extent, potentially promoting stem cell proliferation, accelerating postoperative healing, and enhancing anti-infection capabilities.

[0024] Reference Figures 1 to 12 The PEKK craniofacial patch of this application includes a lateral soft tissue attachment layer 1, a middle layer 2, and a medial bone-bonding layer 3 arranged sequentially from the outside to the inside along the thickness direction. The lateral soft tissue attachment layer 1 is close to the skin 6, and the medial bone-bonding layer 3 is close to the mandible 7. Each layer adopts different structures and surface morphologies according to different functions and needs to achieve different biological functions.

[0025] The lateral soft tissue attachment layer 1, the intermediate layer 2, and the medial bone-bonding layer 3 are all made of PEKK material. Compared with titanium alloy, PEKK material has advantages such as high specific heat capacity, X-ray transmission properties, and an elastic modulus closer to that of bone. In addition, it has a lower melting point, is easier to process, and can be processed using 3D printing, reducing economic and time costs.

[0026] Reference Figure 1 , Figure 2 , Figure 5 and Figure 6 The outer soft tissue attachment layer 1 is located on the side of the patch away from the bone tissue and in contact with the outer tissue, with a depth d1 of 80-100 μm. A leaf vein-like hierarchical micro / nanostructure 4 is formed on the surface of the outer soft tissue attachment layer 1. The leaf vein-like hierarchical micro / nanostructure 4 is composed of a micron-scale leaf vein network 41 and a nano-scale microstructure 42. The micron-scale leaf vein network 41 is composed of three levels of branches, and its structure and shape are similar to the structure of leaf veins in natural plants. The length, depth, and spacing of each branch structure vary within a certain size range. This structural morphology simulates the material transport channels of leaf veins in nature, providing a directional migration path for vascular endothelial cells and guiding blood vessels to grow along the vein pattern.

[0027] Specifically, refer to Figure 2The micron-scale leaf vein network 41 includes multiple main leaf veins 411 connected to form a simulated leaf vein network. The multiple main leaf veins 411 ensure that the surface coverage of the simulated leaf vein network is not less than 65%. Multiple lateral leaf veins 412 are connected to each main leaf vein 411. Multiple small leaf veins 413 are connected to each lateral leaf vein 412. The angle between the main leaf veins 411 and the lateral leaf veins 412 is 30°~60°, and the angle between the lateral leaf veins 412 and the small leaf veins 413 is 30°~60°.

[0028] The length of the main vein 411 is 0.6 to 0.8 times the longest side of the patch, the width is 2 to 4 μm, and the depth is 1 to 5 μm. The orientation of the main vein 411 is at an angle of less than 30° to the target blood supply axis, and multiple main veins 411 are generally parallel.

[0029] The length of lateral vein 412 is 0.2 to 0.5 times that of the main vein 411, the width is 1 to 2 μm, and the depth is 0.5 to 3 μm. The distance between two adjacent lateral veins 412 is 300 to 500 μm.

[0030] The length of leaflet 413 is 100~130μm, the width is 0.5~1μm, the depth is 0.2~1μm, and the distance between two adjacent leaflet 413 is 1~3μm.

[0031] The distance between two adjacent main veins 411 is 2~3μm, so that lateral veins 412 and small veins 413 derived from the main veins 411 can be distributed between the two main veins 411, so that the tertiary veins are distributed as much as possible on the surface of the outer soft tissue attachment layer 1.

[0032] Reference Figure 3 and Figure 4 The nanoscale microstructure 42 consists of nanopillars disposed within the voids of the micron-scale leaf vein network 41. Specifically, the nanopillars have a diameter of 100–200 nm, a height of 100–500 nm, and a spacing of 100–300 nm between adjacent nanopillars. By increasing surface roughness and forming a specific surface topology, the nanoscale microstructure 42 (nanopillars) enhances cell adhesion and, moreover, its sharp nanostructure can physically pierce bacterial cell membranes, thereby achieving a physical antibacterial function.

[0033] Reference Figure 6 and Figure 8 The middle layer 2 is the main part of the patch, which is left untreated, and its size and shape are determined according to the patient's needs.

[0034] Reference Figure 8The thickness d2 of the inner bone-bonding layer 3 is 4-8 mm, and it has a porous structure with the same thickness as itself. The pore size of the porous structure is 100-600 μm, the porosity is 20%-70%, and the bone-side penetration rate is greater than or equal to 10%. This structure can promote bone ingrowth, cell migration, and tissue fluid exchange, and provide mechanical locking. (Refer to...) Figures 9 to 12 The porous structure is composed of a single type of unit cell, which can be one of the following: gyriodine, diamond, lidinoid, or splitp unit cell structures. By setting up a micron-level leaf vein network 41 and a nano-level microstructure, the mechanical microenvironment of the extracellular matrix can be simulated, thereby promoting stem cell proliferation, endogenously promoting cell growth and postoperative recovery, and improving the biocompatibility of the patch. Furthermore, the pore size of the porous structure is preferably 600 μm. When the pore size is 600 μm, the uniform wall shear stress of the patch caused by tissue fluid flow is minimized, and the proportion of the wall area suitable for cell growth and osteogenic differentiation is maximized, making it more suitable for cell adhesion, proliferation, and osteogenic differentiation.

[0035] Reference Figure 7 The PEKK craniofacial patch also features multiple through-holes 5 that sequentially penetrate the outer soft tissue attachment layer 1, the intermediate layer 2, and the inner bone-bonding layer 3 along the thickness direction, facilitating the flow of tissue fluid and the exchange of substances. The diameter of the through-holes 5 is on the order of millimeters, and the porosity is greater than or equal to 10%. This facilitates the exchange of tissue fluid on both sides of the patch.

[0036] During processing, the outer soft tissue attachment layer 1, the middle layer 2, and the inner bone-bonding layer 3 are first integrally formed using 3D printing. Then, a femtosecond laser is used to process the micron-scale leaf vein network 41 and the nanoscale fine structure 42. This not only has the advantages of structural parameterization and a clear process window, but also supports stable production for both personalized and standardized processes. In addition, the surface roughness Ra of the outer soft tissue attachment layer 1 after femtosecond laser processing is 5~10μm. If this value is not achieved after processing, it can be made to meet the requirements through surface roughening treatment and other methods.

[0037] It should be noted that the porosity, roughness, and other parameters of the PEKK craniofacial patch in this application embodiment can be appropriately adjusted according to the location where the patch is installed, for example: For mandibular bone defect repair: Considering that the mandible needs to withstand a large chewing force, the porosity of the porous structure of the inner bone-bonding layer 3 can be appropriately reduced to 20%~40% to improve the mechanical strength of the patch.

[0038] For the repair of defects in the top of the skull: Since the top of the skull requires high aesthetic restoration, the roughness of the leaf-vein-like hierarchical micro / nano structure 4 of the outer soft tissue attachment layer 1 can be appropriately adjusted to 3-5 μm. This makes the surface of the patch closer to the roughness of the normal skull surface, reducing irritation to the soft tissue and improving the naturalness of the appearance. Furthermore, the overall thickness of the patch can be customized according to the thickness of the skull at the defect site, generally controlled within 2-5 mm, ensuring a smooth transition with the surrounding normal skull structure.

[0039] Reference Figure 13 The embodiments of this application also include a method for processing PEKK craniofacial patches, comprising the following steps: Step S1. Obtain CT data of the skull by optically scanning the location where the patch needs to be installed on the patient (taking the skull as an example), and reconstruct a three-dimensional model of the skull based on the CT data.

[0040] Step S2. Design the geometry of the PEKK skull patch based on the defect area in the 3D model.

[0041] Step S3. Optimize the structure using finite element analysis. Determine the overall structure while ensuring sufficient overall structural strength, and add porous structures and through holes.

[0042] Step S4. Use 3D printing to prepare a prototype of the PEKK craniofacial patch.

[0043] Step S5. Using femtosecond laser processing, leaf vein-like micro / nanoscale structures are fabricated on the outer soft tissue attachment layer of the prepared PEKK craniofacial patch prototype.

[0044] Step S6. Detect the roughness of the side of the PEKK skull patch that is in contact with the soft tissue (the surface of the outer soft tissue attachment layer 1). If the roughness does not meet the requirements, a rough surface suitable for cell growth is formed by sandblasting roughening treatment, with a surface roughness Ra of 5~10μm.

[0045] In summary, the PEKK craniofacial patch of this application constructs a porous structure on the bone contact side, which not only expands the contact area to form mechanical locking but also promotes bone ingrowth. On the soft tissue contact side, a micron-scale leaf vein network-nanospiky coupling structure is set. The structure of the micron-scale leaf vein network (main / lateral / small leaf veins) simulates the material transport channels of leaf veins in nature, which can provide a directional migration path for vascular endothelial cells and guide blood vessels to grow along the leaf vein direction. The nanoscale microstructure (nanopillars) increases the surface roughness and forms a specific surface topology, which can enhance the cell adhesion ability on the one hand, and on the other hand, its sharp nanostructure can physically pierce the bacterial cell membrane, thereby achieving a physical antibacterial function.

[0046] This application's PEKK craniofacial patch integrates macroscopic leaf vein-like orientation, micro / nano-scale structure, and porous structure into a single PEKK patch, achieving a triple interface synergistic optimization of "strong lateral integration - good lateral blood supply - overall anti-infection". Through laser micro / nano processing technology, heat-affected zones and recast layers are avoided, ensuring stable and repeatable processes with no risk of coating peeling. This lays a crucial surface engineering foundation for PEKK implants to move from the laboratory to clinical applications.

[0047] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A PEKK craniofacial patch, characterized in that, The structure comprises, from the outside in, an outer soft tissue attachment layer, an intermediate layer, and an inner bone-bonding layer. The surface of the outer soft tissue attachment layer features a leaf vein-like hierarchical micro / nanostructure. This leaf vein-like hierarchical micro / nanostructure includes a micrometer-scale leaf vein network and nanometer-scale microstructures within the gaps of the micrometer-scale leaf vein network. The micrometer-scale leaf vein network includes multiple main veins connecting to form the leaf vein network; each main vein connects to multiple lateral veins; and each lateral vein connects to multiple small veins. The nanometer-scale microstructures are nanopillars. The inner bone-bonding layer has a porous structure. The outer soft tissue attachment layer, intermediate layer, and inner bone-bonding layer are all made of PEKK material.

2. The PEKK craniofacial patch according to claim 1, characterized in that, The angle between the direction of the main vein and the target blood supply axis is less than 30°, and the distance between two adjacent main veins is 2~3μm.

3. The PEKK craniofacial patch according to claim 1, characterized in that, The length of the main vein is 0.6 to 0.8 times the longest side of the patch, the width is 2 to 4 μm, and the depth is 1 to 5 μm; the length of the lateral veins is 0.2 to 0.5 times the length of the main vein, the width is 1 to 2 μm, and the depth is 0.5 to 3 μm; the distance between two adjacent lateral veins is 300 to 500 μm; the length of the small veins is 100 to 130 μm, the width is 0.5 to 1 μm, and the depth is 0.2 to 1 μm; the distance between two adjacent small veins is 1 to 3 μm; the angle between the main vein and the lateral veins is 30° to 60°, and the angle between the lateral veins and the small veins is 30° to 60°.

4. The PEKK craniofacial patch according to claim 1, characterized in that, The nanopillars have a diameter of 100-200 nm, a height of 100-500 nm, and a spacing of 100-300 nm between adjacent nanopillars.

5. The PEKK craniofacial patch according to claim 1, characterized in that, The outer soft tissue attachment layer, the middle layer, and the inner bone bonding layer are integrally formed by 3D printing.

6. The PEKK craniofacial patch according to claim 5, characterized in that, Both the micron-scale leaf vein network and the nano-scale microstructure are fabricated using femtosecond laser processing.

7. The PEKK craniofacial patch according to claim 1, characterized in that, The porous structure has a pore size of 100~600 μm, a porosity of 20%~70%, and a bone side penetration rate of ≥10%; the porous structure is composed of a single unit cell; the unit cell structure is one of gyriod, diamond, lidinoid, or splitp unit cell structures.

8. The PEKK craniofacial patch according to claim 1, characterized in that, The PEKK craniofacial patch has multiple through holes that pass through the outer soft tissue attachment layer, the middle layer and the inner bone bonding layer in sequence along the thickness direction, allowing tissue fluid flow and material exchange; the diameter of the through holes is on the order of millimeters and the porosity is greater than or equal to 10%.

9. The PEKK craniofacial patch according to claim 1, characterized in that, The surface of the outer soft tissue attachment layer is roughened by sandblasting, and its surface roughness Ra is 3~20μm.

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