3D-printed intervertebral fusion cage

Abstract

The application discloses a 3D-printed intervertebral fusion cage, which is used to solve the problem of poor bone ingrowth effect of the prior art fusion cage, slow degradation speed, and early release of active ingredients, and the structure comprises a frame and an embedded pipe, the embedded pipe is arranged in the frame, the components are all made of degradable metal materials and can be gradually degraded in the human body, the embedded pipe is further encapsulated with active ingredients for promoting bone growth, and the active ingredients are released with the degradation of the embedded pipe, so that the early release of the drugs in the embedded pipe is avoided, long-acting effect is achieved, and of course a net beam is arranged in the gap of the frame, and the porous structure formed by the net beam further increases the bone ingrowth effect; the application creatively uses a 3D process to realize the encapsulation of the active ingredients and the forming of the porous support, and is combined with the degradable metal to realize the sustained release, so that a good growth condition is provided for the bone ingrowth in the porous support, the effect of the growth factors is fully played, and the treatment effect is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of orthopedic implants, and particularly relates to a 3D-printed intervertebral fusion cage. BACKGROUND

[0002] Traditional intervertebral fusion surgery generally adopts autologous bone transplantation, but this surgery not only causes complications in the bone donor area, but also has adverse reactions such as instability of the fused segment in the surgical segment. Therefore, the prior art proposes an intervertebral fusion cage, which can significantly improve the defects of traditional bone graft fusion surgery and improve the fusion effect by wrapping the transplanted bone with the intervertebral fusion cage. Titanium alloy is widely used as the material of the intervertebral fusion cage because of its good corrosion resistance, low elution rate and nearly chemical inert titanium eluate. However, the elastic modulus of titanium alloy is 70-100 GPa, while the elastic modulus of cortical bone is generally 18.6 GPa, which is obviously quite different from bone tissue, and stress shielding is easily caused.

[0003] In order to solve the above problems, the prior art proposes a porous intervertebral fusion cage, wherein the porous support is a net structure formed by repeatedly stacking simple unit structures. Compared with the traditional machining structure, the mechanical properties of the porous fusion cage are more similar to human bone, and the porous structure has a larger surface area, which can grow into the porous structure and better fuse with human bone. However, the closer the porous structure is to the middle, the worse the bone growth effect is, that is, the bone tissue tends to deposit and grow outside the support. If the bone tissue cannot effectively grow into the porous structure, the expected therapeutic effect cannot be achieved. SUMMARY

[0004] The purpose of the present application is to provide a 3D-printed intervertebral fusion cage, which creatively uses 3D technology to realize the encapsulation of active ingredients and the formation of a porous support, reduces the occurrence of high-temperature inactivation, and at the same time cooperates with the combination of degradable metal to realize "sustained release", provides a good growth condition for bone growth in the porous support, fully plays the effect of growth factors, and improves the therapeutic effect.

[0005] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0006] A 3D-printed intervertebral fusion cage, comprising: a frame, an embedded pipe, the frame is a spindle-like structure, a net beam is further arranged in the gap of the frame, the embedded pipe is arranged in the frame, the outer wall of the embedded pipe is fixedly connected with the net beam, the embedded pipe is filled with bone regeneration inducing components, and the embedded pipe is made of degradable metal material, the pipe wall of the embedded pipe is thinner than other parts of the frame, and the embedded pipe will degrade earlier than the frame after being implanted for a period of time.

[0007] Further, the frame is a spindle-like structure composed of a top surface, a bottom surface and two end surfaces and two side surfaces, the two end surfaces are a clamping end and an implanting end respectively, the implanting end is a curved surface protruding outward in the middle, and the implanting end is smoothly connected with other surfaces, and the clamping end is a plane, and the edge of the clamping end is connected with other surfaces.

[0008] Further, a cover body is further included, the cover body is a ring-shaped cover plate with the same shape as the top surface, and the top surface of the frame is not provided with a panel, and the top surface is closed after being connected with the cover body.

[0009] Further, a sealing cover is inlaid on the cover body, the position of the sealing cover on the cover body corresponds to the position of the embedded pipe in the frame, and after the frame is connected with the cover body, the sealing cover is inserted into the embedded pipe to seal the embedded pipe.

[0010] Further, the bottom surface of the frame and the cover body are both provided with a baffle.

[0011] Further, the frame is built by a ring beam and a support row, the ring beam is horizontally arranged in the frame and supports the two side surfaces and the two side surfaces, and a plurality of support rows are further arranged on the upper and lower surfaces of the ring beam to support the top surface and the bottom surface, and a plurality of porous structures formed by net beams are arranged at the gaps of the frame to support.

[0012] Further, the frame and the net beams in the frame are both formed by 3D printing, and the net beams are three-dimensional grid porous structures.

[0013] Further, the clamping end is provided with a threaded hole and a bayonet for clamping, and the side surfaces located on the two sides of the frame are provided with side windows.

[0014] The application has at least the following beneficial effects:

[0015] (1) The titanium alloy container is manufactured by 3D printing process to have a porous structure, has higher production freedom, can flexibly adjust parameters such as voids, can accurately form a complex structure, solves the problem that a traditional machining method cannot form a porous structure, and the porous structure can improve the mechanical properties of the titanium alloy;

[0016] (2) The application creatively adopts a structure form in which an embedded pipe cooperates with a porous support, although the structure is fixed by welding, the surface area of the structure is large, welding heat is rapidly conducted, and the embedded pipe is not directly affected, the technical problem that an active component cannot be encapsulated by welding and other thermal processing methods in the prior art is overcome, and conditions for in-vivo delayed release are created;

[0017] (3) It has a “continuous release” effect, rather than concentrated release in the early stage of implantation. Since encapsulation cannot be achieved in the existing technology, only the surface has a drug coating. The anti-inflammatory drug coated on the surface will be released in the early stage of implantation, that is, in the inflammatory process of bone tissue regeneration. In this application, there are also active ingredients encapsulated in the tube. These ingredients can be released after a period of time in the body, induce the formation of fibrous tissue, constitute soft healing tissue, and stimulate the differentiation of mesenchymal stem cells, thus better accelerating the bone tissue regeneration process. Attached Figure Description

[0018] The accompanying drawings, which form part of this application, 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.

[0019] Attached Figure

[0020] Figure 1 A schematic diagram of the structure of this application is shown.

[0021] Figure 2 The schematic diagram illustrates the structural configuration of the assembly in this application;

[0022] Figure 3 This schematic diagram illustrates the structural features of the frame portion in this application from a top view.

[0023] Figure 4 This schematic diagram illustrates the structural features of the framework in this application.

[0024] Figure 5 A schematic diagram of the cover structure is shown.

[0025] Figure 6 It shows along Figure 3 A schematic diagram of the structure cut along line AA in the middle;

[0026] in:

[0027] 1-Framework;

[0028] 11-Clamping end, 12-Implantation end, 13-Side window, 14-Ring beam, 15-Support row, 16-Baffle, 17-Net beam;

[0029] 2-Capping body, 21-Bone graft window, 22-Sealing cap, 3-Insertion tube. Detailed Implementation

[0030] To provide a detailed description of specific embodiments of the present invention in conjunction with the accompanying drawings, numerous specific details are set forth in the following description to facilitate a thorough understanding of the invention. However, the present invention can be practiced in many ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed below. In this invention, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0031] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature. Example

[0032] like Figures 1-2 The diagram shows an intervertebral fusion device designed to address the issue of poor bone ingrowth in existing fusion devices. It also features a slower degradation rate, preventing premature release of active ingredients. The device comprises a frame 1 and a tube 3, with the tube 3 housed within the frame 1. All components are made of biodegradable metal materials that gradually degrade within the body. The tube 3 also encapsulates active ingredients that promote bone growth, releasing them as it degrades. This creates favorable growth conditions in areas of the frame where ingrowth is difficult, and also prevents premature release of the medication within the tube 3, ensuring a long-lasting effect. Furthermore, mesh beams 17 are incorporated into the gaps in the frame 1. The porous structure formed by the mesh beams 17 further increases the attachment area for bone cells, enhancing the ingrowth effect when used in conjunction with the tube 3.

[0033] Frame 1 is a spindle-shaped structure composed of two sides, a top surface, a bottom surface, and two end faces, as shown below. Figure 2As shown, the two end faces are the clamping end and the implantation end, respectively. The implantation end is a curved surface that protrudes outward from the center and is smoothly connected to other surfaces. The clamping end is a flat surface with its edge connected to other surfaces. The clamping end is provided with threaded openings and bayonets for clamping, which are used in conjunction with existing clamping devices. Side windows 13 are provided on the two sides of the frame 1. In addition, a baffle 16 is provided on the side of the bottom surface. The baffle 16 is a strip-shaped piece that protrudes from the bottom surface. After implantation, it increases the friction with the vertebral body and prevents displacement.

[0034] It should be noted that frame 1 also has a channel that runs through the top and bottom surfaces, which is filled with bone and compacted before implantation.

[0035] The frame within the border of frame 1 is not a single, solid structure, but rather a frame structure constructed from ring beams 14 and bracing 15, as shown below. Figure 4 As shown, the two side edges of the frame 1 are provided with ring structures to maintain the shape of the sides, and the ring beam 14 is horizontally set inside the frame 1 to support the two sides. Several support rows 15 are also provided on the upper and lower surfaces of the ring beam 14 to support the top and bottom surfaces. One end of the support row 15 is vertically set on the ring beam 14, and the other end is connected to the top and bottom surfaces respectively, providing support for the top and bottom surfaces and playing the main supporting role. In addition, mesh beams 17 are provided in the gaps of the frame 1. The porous structure formed by the mesh beams 17 has a rough surface and a greatly increased surface area, which facilitates the attachment and growth of bone cells. At the same time, compared with the traditional solid structure, the combination of mesh beams 17 and frame 1 can reduce the product weight while maintaining the strength of use. However, traditional processing technology is difficult to form. Therefore, this application uses 3D printing to form the frame 1.

[0036] It should be noted that the mesh beam 17 is a three-dimensional mesh structure formed by complex lines in space. It can be a disordered mesh structure or a regular mesh structure composed of structural units such as rhombic dodecahedrons, tetrahedrons, and diamond types.

[0037] According to common knowledge, bone regeneration can be divided into three processes: inflammation, repair, and remodeling. After bone injury, blood coagulation induces hematoma formation, triggering an inflammatory response. A large number of immune cells enter the injured area, releasing immune factors such as IFN-γ to activate macrophages. Increased expression of cytokines such as TGF-β leads to the formation of healing tissue. During repair, fibrous tissue gradually forms, constituting soft callus tissue. Mesenchymal stem cells begin to differentiate under the influence of growth factors and mechanical stimulation. In the central region of bone injury, oxygen concentration is too low, preventing osteoblast formation. Mesenchymal stem cells first differentiate into chondrocytes, which produce angiogenesis factors to promote angiogenesis. After angiogenesis, oxygen concentration recovers, leading to endochondral ossification and the formation of woven bone. Finally, the remodeling process begins, where woven bone is replaced by layered bone, restoring the original shape and size of the bone. During this bone regeneration process, bone morphogenetic proteins play a crucial role. BMP (Bioblastoid protein) is a group of highly conserved functional proteins with similar structures. It belongs to the TGF-β family and can stimulate DNA synthesis and cell replication, thereby promoting the directed differentiation of mesenchymal cells into osteoblasts. It plays an important role in the repair and remodeling processes.

[0038] Existing technologies use methods such as plasma spraying and electrochemical deposition to attach hydroxyapatite to the surface of titanium alloys, thereby inducing bone growth. For drug-eluting coatings, which are more effective, the outer layer of drug is released first upon contact with body fluids after implantation, concentrating on the inflammatory phase. However, the thickness of the drug coating is limited, and it cannot be continuously released into the repair or remodeling process. Therefore, the role of active ingredients, including BMPs, is limited. In addition, the active ingredients in the drug coating are extremely sensitive to the processing method and require strict control of the processing temperature. Otherwise, the activity of the drug coating will be greatly affected. Existing technologies use polymer materials to encapsulate the active ingredients into particles and then attach the particles to a mesh structure. This encapsulation method does not generate high temperatures, and the encapsulated active ingredients are not easily deactivated. However, this method is complex, costly, and has a small loading capacity.

[0039] In this embodiment, the active ingredient is loaded through the tube 3, resulting in a loading capacity far greater than that of particle coating. Furthermore, the degradation rate of biodegradable metals is relatively slow, and the release time can be further controlled by adjusting the wall thickness to prevent premature release. The 3D printing process allows for easy adjustment of the wall thickness without significantly increasing manufacturing costs. Figure 3 As shown, the embedded tubes 3 are evenly arranged in the mesh beams 17 of the frame 1. The middle part of the embedded tubes 3 is connected to the ring beam 14. The outer wall of the embedded tubes 3 is fixedly connected to the mesh beams 17. The tube wall of the embedded tubes 3 is thinner than other parts of the frame 1. The embedded tubes 3 are sealed by the sealing cap 22.

[0040] It should be noted that the fusion device is under continuous stress after implantation. The inlay tube 3 is connected to the mesh beam 17 and the ring beam 14. The pressure on the fusion device is partially transmitted to the inlay tube 3 through the mesh beam 17. After a period of time, the part of the wall of the inlay tube 3 that is under greater stress will first experience pitting corrosion. The pitting corrosion expands into a rupture, and the active ingredients are slowly released through the rupture, which can exert their effects in the middle and late stages of bone regeneration. In addition, since the inlay tube 3 is located in the mesh beam 17, the bone growth-promoting environment formed after the release of the active ingredients is conducive to the inward ingrowth of bone cells, rather than just the ingrowth on the outside of the mesh beam 17.

[0041] The fusion device itself is small in size, and the insert 3 located in it is even smaller. Obviously, it cannot be assembled directly by hand. The heat generated by hot processing methods such as welding is sufficient to deactivate the active ingredients filled in it. Therefore, the methods provided by the prior art are difficult to complete the assembly of the insert 3 and the sealing cap 22.

[0042] In this embodiment, a cover 2 is also provided, and the top surface of the frame 1 does not have a panel; it is closed by the cover 2, such as... Figure 5 As shown, the cover 2 has the same shape as the bottom surface of the frame 1, and is also equipped with a mesh beam 17 and a baffle 16. The difference is that the cover 2 is also equipped with a bone graft window 21 and a sealing cover 22. The area of ​​the bone graft window 21 is larger than that of the side window 13. Before implantation, bone blocks are filled in. The sealing cover 22 is set on the cover 2. The position of the sealing cover 22 on the cover 2 corresponds to the position of the tube 3. After the frame 1 and the cover 2 are assembled, the sealing cover 22 is inserted into the tube 3 to seal the tube 3. Since the fusion device itself is a biodegradable metal, only by welding can the metallurgical bonding of the two be ensured to guarantee the stability of the structure. Otherwise, displacement of the cover 2 and the frame 1 will occur during the degradation process, resulting in serious consequences.

[0043] It should be noted that the welding process between the cover 2 and the frame 1 in this embodiment is carried out in a low-temperature environment, and the mesh frame of the cover 2 only fills the openings on the surface of the cover 2, such as... Figure 6 As shown, since the welding part is at the edge of the cover 2 and is a certain distance from the embedded tube 3, and the contact area between the mesh beam 17 of the cover 2 and the sealing cover 22 is much smaller than the contact area between the mesh beam 17 and the external environment, the sealing cover 22 receives less heat. In contrast, the frame 1 has a more complex mesh beam 17 structure, and the mesh beam 17 structure has a larger heat exchange area with the external environment, so the welding heat can be dissipated more quickly, thus greatly reducing the impact on the embedded tube 3.

[0044] Of course, before use, the product will be coated with an anti-inflammatory drug. The coated drug will be degraded first in the body environment, followed by the thin-walled tube 3, which will be degraded and the active ingredients will be released to promote bone cell growth. Thus, the outer coated drug, the tube 3 and the drug inside the tube 3 form a continuous release system, which continuously releases the drug at different stages of human bone growth to fully exert the drug's effect.

[0045] It should be noted that the active ingredient is selected by the user based on the existing technology. The active ingredient mentioned in this application is recombinant protein lyophilized powder.

[0046] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0047] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A 3D-printed interbody fusion device, characterized in that: include: The system comprises a frame, a tube, and a cap. The frame is a spindle-shaped structure with mesh beams embedded in its gaps. The tubes are evenly distributed within the mesh beams of the frame. The outer wall of each tube is fixedly connected to the mesh beams. The tubes are filled with components that induce bone regeneration and are made of biodegradable metal. The tube walls are thinner than other parts of the frame and will degrade before the frame itself after implantation. The cap is an annular cover with the same shape as the top surface of the frame. The top surface of the frame does not have a panel. The cap is connected to the top surface of the frame, sealing it. A sealing cap is embedded in the cap, and its position corresponds to the position of the tube within the frame. After the frame and cap are connected, the sealing cap is inserted into the tube to seal it and maintain the preservation conditions within the tube. The frame and its mesh beams are formed using 3D printing, and the mesh beams are a porous structure composed of a three-dimensional mesh.

2. The 3D-printed interbody fusion device according to claim 1, characterized in that: The frame includes a bottom surface, two end surfaces, and two side surfaces. The two end surfaces are a clamping end and an implantation end, respectively. The implantation end is a curved surface that bulges outward from the center and is smoothly connected to the other surfaces. The clamping end is a plane and its edge is connected to the other surfaces.

3. A 3D-printed interbody fusion device according to claim 2, characterized in that: Baffles are provided on the bottom surface of the frame and the cover.

4. A 3D-printed interbody fusion device according to claim 2, characterized in that: The frame also includes: a ring beam and bracing. The ring beam is horizontally set inside the frame to support the two end faces and the two sides, while several bracings are also set on the upper and lower faces of the ring beam to support the top and bottom surfaces.

5. A 3D-printed interbody fusion device according to claim 2, characterized in that: The clamping end is provided with a threaded opening and a bayonet for clamping, and the sides of the frame are provided with side windows on both sides.

6. A 3D-printed interbody fusion device according to claim 1, characterized in that: The component that induces bone regeneration is a recombinant protein lyophilized powder.

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