A porous structure fusion device

Abstract

The present invention provides a porous structure fusion device, comprising: a tubular member, and a fusion device body sleeved on the tubular member, and a loose expansion portion, wherein the loose expansion portion is arranged between the tubular member and the fusion device body and is used to connect the fusion device body and the tubular member; wherein the loose expansion portion is a porous structure formed by connecting a plurality of unit cell structure arrays, and the unit cell structure is a double pyramid structure formed by connecting a plurality of micro rods. The present invention is beneficial to the proliferation, differentiation and growth of osteoblasts by modifying the interior of the existing fusion device body, forming a tight bone implantation interface, and filling the unit cell structure, so that the implanted fusion device body is more likely to form a tight bone callus and bone bridge, which is more conducive to bone ingrowth.

Description

Technical Field

[0001] The invention relates to the field of medical devices, in particular to a porous structure fusion device. Background Art

[0002] Chronic strain-induced intervertebral joint degeneration and surrounding tissue compression are the main causes of cervical spondylosis, and a series of cervical radiculopathy syndromes often seriously affect the lives of patients. Anterior decompression and fusion of cervical spondylosis is the preferred procedure for degenerative cervical spondylosis that is ineffective with conservative treatment. However, the overall elastic modulus of titanium alloy fusion devices used in clinical practice is relatively high, and direct application between vertebral bodies is prone to implant deposition and "stress shielding". Therefore, solid titanium alloy intervertebral fusion devices are not clinically applicable. Currently, porous titanium alloys are mostly used for implantation. However, a cavity is opened in the middle of the existing porous structure fusion device body, which reduces the fatigue strength of the fusion device while reducing the elastic modulus, resulting in postoperative failure of the fusion device. Summary of the invention

[0003] The purpose of the present invention is to provide a novel cervical vertebra porous structure fusion device, which reduces the elastic modulus while ensuring the strength of the fusion device, promotes the formation of callus and bone bridge closely connected with the bone after the fusion device is implanted, and effectively promotes bone growth.

[0004] The technical solution provided by the present invention is as follows: a porous structure fusion device, comprising:

[0005] A cylindrical member, and a fusion device body sleeved on the cylindrical member;

[0006] A loose expansion part, which is arranged between the tubular member and the fusion device body and is used to connect the fusion device body and the tubular member;

[0007] The loosely expanded portion is a porous structure formed by connecting a plurality of unit cell structure arrays, and the unit cell structure is a double pyramid structure formed by connecting a plurality of micro rods.

[0008] In the present technical solution, the interior of the existing fusion device body is modified, and the tubular member and the fusion device body are connected through a loose expansion part to form an internal frame, thereby reducing the elastic modulus of the fusion device itself, making it less likely to produce implant deposition and "stress shielding", which is beneficial to the proliferation, differentiation and growth of osteoblasts, forming a tight intrabone implant interface, and filling the loose expansion part, so that the fusion device body after implantation is more likely to form a tight callus and bone bridge, which is more conducive to bone ingrowth.

[0009] Preferably, it further comprises: at least two reinforcing ribs, one end of the reinforcing rib is connected to the outer wall of the tubular member, and the other end of the reinforcing rib is connected to the inner wall of the fusion device body.

[0010] In the present technical solution, reinforcing ribs are provided between the cylindrical member and the fusion device body, thereby ensuring the bearing capacity of the fusion device, and enhancing the internal strength of the fusion device while ensuring the internal porous structure.

[0011] Preferably, at least one first filling hole is formed on the outer peripheral wall of the cylindrical member.

[0012] In the present technical solution, by opening a first filling hole on the cylindrical member, the first filling hole is conducive to cell adhesion growth, extracellular matrix deposition, nutrient and oxygen entry, and metabolic product discharge, and is also conducive to the growth of blood vessels and nerves.

[0013] Preferably, the loose support portion extends into the first filling hole and fills the first filling hole.

[0014] In this technical solution, the loose expansion portion extends into the first filling hole and fills the first filling hole, so that the space in the first filling hole is further changed, thereby forming a multi-level porous structure. The porous structure is conducive to cell adhesion and growth, extracellular matrix deposition, nutrition and oxygen entry, and metabolic product discharge. It is also conducive to blood vessel and nerve growth, and is a relatively ideal fusion device structure. Specifically for bone implants, the porous structure helps osteoblasts grow into the pores and can generate bony components. On the other hand, the surface roughness of the porous implant is controllable, which is conducive to the adhesion and growth of bone cells. Finally, a well-designed porous structure is conducive to reducing the elastic modulus of solid solid implants and avoiding the "stress shielding" effect of intervertebral fusion.

[0015] Preferably, at least one second filling hole is formed on the peripheral wall of the fusion device body.

[0016] In this technical solution, by opening a second filling hole on the peripheral wall of the fusion device body, the second filling hole is conducive to cell adhesion growth, extracellular matrix deposition, nutrient and oxygen entry, metabolic product discharge, and also conducive to the growth of blood vessels and nerves.

[0017] Preferably, the loose support portion extends into the second filling hole and fills the second filling hole.

[0018] In this technical solution, the loose expansion portion extends into the second filling hole and fills the second filling hole, so that the space in the second filling hole is further changed, thereby forming a multi-level pore structure. The porous structure is conducive to cell adhesion and growth, extracellular matrix deposition, nutrition and oxygen entry, and metabolic product discharge. It is also conducive to blood vessel and nerve growth, and is a relatively ideal fusion device structure. Specifically for bone implants, the porous structure helps osteoblasts grow into the pores and can generate bony components. On the other hand, the surface roughness of the porous implant is controllable, which is conducive to the adhesion and growth of bone cells. Finally, a well-designed porous structure is conducive to reducing the elastic modulus of solid solid implants and avoiding the "stress shielding" effect of intervertebral fusion.

[0019] Preferably, a plurality of protrusions are formed at both ends of the fusion device body.

[0020] In the present technical solution, protrusions are provided at both ends of the fusion device body, so that when the fusion device is implanted, the two ends of the fusion device body can better fit with the cervical vertebrae bones, thereby improving the connection stability between the fusion device and the vertebral body.

[0021] Preferably, the fusion device body is integrally formed and has a first end face and a second end face for docking with the vertebral body, and at least two inclined mounting holes are provided on the side wall of the fusion device body, which are inclined toward the first end face and the second end face respectively, for fixing the fusion device body on the vertebra.

[0022] In the technical solution, by opening two mounting holes, when the fusion device is implanted, it can be fixed to the upper and lower bones of the cervical vertebra respectively by screws to improve the stability of the implanted fusion device.

[0023] Preferably, the two mounting holes respectively form an angle of 15-25 degrees with the two end surfaces of the fusion device body.

[0024] Preferably, the micro-rod is a straight rod or a curved rod.

[0025] Compared with the prior art, the porous structure fusion device provided by the present invention has the following beneficial effects:

[0026] 1. The present invention transforms the interior of the existing fusion device body, adds a tubular part and a loose part connecting the tubular part and the fusion device body, so that the fusion device body further forms an internal frame, reduces the elastic modulus of the fusion device itself, is not easy to produce implant deposition, "stress shielding" and the like, is conducive to the proliferation, differentiation and growth of osteoblasts, forms a tight intrabone implantation interface, and the filling of the single cell structure makes it easier for the implanted fusion device body to form a tight bone callus and bone bridge, which is more conducive to bone ingrowth.

[0027] 2. The present invention can form a multi-level pore structure by arranging loose expansion parts between the tubular member and the fusion device body, in the first filling hole, and in the second filling hole. The porous structure is conducive to cell adhesion and growth, extracellular matrix deposition, nutrition and oxygen entry, and metabolic product discharge. It is also conducive to blood vessel and nerve growth, and is a relatively ideal fusion device structure. Specifically for bone implants, the porous structure helps osteoblasts grow into the pores and can generate bony components. On the other hand, the surface roughness of the porous implant is controllable, which is conducive to the adhesion and growth of bone cells. Finally, the porous structure is conducive to reducing the elastic modulus of solid solid implants and avoiding the "stress shielding" effect of intervertebral fusion. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The preferred implementation scheme will be described below in a clear and understandable manner with reference to the accompanying drawings to further illustrate the above-mentioned characteristics, technical features, advantages and implementation methods of a porous structure fusion device.

[0029] Figure 1 It is a schematic diagram of the top view of the structure of the present invention;

[0030] Figure 2 It is a structural schematic diagram of another embodiment of the present invention;

[0031] Figure 3 yes Figure 2 A schematic diagram of the three-dimensional structure of an unfilled loose open portion;

[0032] Figure 4 It is a structural schematic diagram of another embodiment of the present invention;

[0033] Figure 5 It is a structural schematic diagram of another embodiment of the present invention;

[0034] Figure 6 yes Figure 5 A schematic diagram of a three-dimensional structure from another perspective of an unfilled loose open portion;

[0035] Figure 7 yes Figure 6 Another perspective structural schematic diagram of ;

[0036] Figure 8 It is another perspective structural diagram of 6;

[0037] Fig. 9 It is a schematic diagram of the unit cell structure;

[0038] Fig.10 It is a simulation schematic diagram of the unit cell structure;

[0039] Fig.11 yes Figure 4 Schematic diagram of the application of the medium fusion device;

[0040] Fig.12 This is a schematic diagram of the reconstruction after microCT scanning of the 6-week sample;

[0041] Fig.13 This is a schematic diagram of the reconstruction after microCT scanning of the 12-week sample;

[0042] Fig.14 This is a schematic diagram of the reconstruction after microCT scanning of the 24-week sample;

[0043] Fig.15 It is a schematic diagram of hard tissue sections of samples at 6 weeks, 12 weeks, and 24 weeks;

[0044] Fig.16 It is a line diagram of the bone ingrowth percentage of the samples at different time points for 6 weeks, 12 weeks, and 24 weeks;

[0045] Fig.17 It is a line diagram of the bone density of samples taken at 6 weeks, 12 weeks, and 24 weeks at different time points.

[0046] Description of the accompanying drawings: tubular member 100 , first filling hole 101 , fusion device body 200 , front wall 201 , rear wall 202 , protrusion 203 , mounting hole 204 , second filling hole 205 , reinforcing rib 3 , loose expansion portion 4 . DETAILED DESCRIPTION

[0047] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings and other implementation methods can be obtained based on these drawings without creative work.

[0048] In order to simplify the drawings, only the parts related to the present invention are schematically shown in each figure, and they do not represent the actual structure of the product. In addition, in order to simplify the drawings and facilitate understanding, in some figures, only one of the parts with the same structure or function is schematically drawn or marked. In this article, "one" not only means "only one", but also means "more than one".

[0049] According to an embodiment provided by the present invention, a porous structure fusion device, such as Figure 1 and Figure 4 As shown, it includes: a cylindrical member 100, and a fusion device body 200 sleeved on the cylindrical member 100; a loose expansion portion 4, which is arranged between the cylindrical member 100 and the fusion device body 200 and is used to connect the fusion device body and the cylindrical member 100; wherein the loose expansion portion 4 is a porous structure formed by connecting a plurality of unit cell structures to each other, such as Fig. 9 As shown, the unit cell structure is a double pyramid structure formed by connecting a number of micro rods. In the specific implementation, it is manufactured by 3D printing technology, so that the cylindrical member 100, the loose expansion portion 4 and the fusion device body 200 are integrated; the loose expansion portion 4 is connected to the cylindrical member 100 to form an internal frame, which provides an internal support structure for the fusion device body 200, so that the fusion device body 200 can reduce the elastic modulus while increasing the strength. The unit cell structure formed by the connection of multiple micro rods has a good pore structure, which is conducive to the formation of callus and bone bridges that are closely connected with the bone after the fusion device body is implanted, which is conducive to bone ingrowth.

[0050] In this embodiment, the fusion device body 200, the cylindrical member 100, and the unit cell structure are all made of titanium alloy materials, replacing the conventional PEEK (polyetheretherketone) materials. When the PEEK material is used, it cannot form a tight bond with the surrounding bone tissue, and there is a tiny gap between the bone interface and the implant interface, which may cause the fusion device to loosen or even fail to fuse. On the other hand, the PEEK fusion device needs to be implanted with autologous or allogeneic bone when used.

[0051] The present invention uses titanium alloy materials, and through additive manufacturing technology, namely 3D printing technology, the porous structure problem of the material can be well solved. 3D printing technology makes it possible to obtain a solid inner and outer frame, with a hollow middle, to reduce weight, lower elastic modulus, and make the overall performance of the entire implant closer to the material properties of human bones. 3D printed porous titanium alloy implants have good animal safety and tolerance. After implantation, they are conducive to the formation of callus and bone bridges that are closely connected with the bone, and at the same time, there is obvious bone growth in the pores. The design of this structure can make the fusion device form a 300um non-hollow structure, which is more conducive to bone growth. Figure 12-14 It can be seen that at the same time point, the 300um hole has more new bone than the 600um hole.

[0052] By modifying the interior of the existing fusion device body 200, adding a cylindrical member 100 and a loose expansion portion 4 connected to the cylindrical member 100, an inner frame 1 is formed. The inner frame 1 bears the axial load and improves the strength of the fusion device itself. Compared with the whole titanium alloy fusion device, the elastic modulus of the fusion device itself is reduced, implant deposition and "stress shielding" are not likely to occur, which is conducive to the proliferation, differentiation and growth of osteoblasts, forming a tight bone implantation interface, and the filling of the single cell structure makes it easier for the implanted fusion device body to form a tight bone callus and bone bridge, which is more conducive to bone ingrowth;

[0053] like Fig.10As shown, in the specific implementation, the unit cell structure formed by the microrods is formed by connecting the center points of two adjacent faces of the inner wall of a cube with straight rods or curved rods. In the specific implementation process, it is also possible to select such a double pyramid on a cuboid according to needs. In the present technical solution, it is preferably connected with curved rods. When the side length of the cube is L, R = 0.45 times the side length. When R is infinite, it is a straight line. The curved rods form double tetrahedrons. The curved rods themselves have a certain variable space. In addition to being able to form the shape of a double tetrahedron, they can also increase the toughness of the porous structure and reduce the elastic modulus of the product. The straight rods only rely on the structural deformation of the double tetrahedron to reduce the elastic modulus of the product. The formed double pyramid structure has more pore levels, which is conducive to bone growth.

[0054] In another embodiment of the present invention, Figure 2 and Figure 5 At least two reinforcing ribs 3 are shown, one end of the reinforcing rib 3 is connected to the outer wall of the tubular member 100 , and the other end of the reinforcing rib 3 is connected to the inner wall of the fusion device body 200 . A plurality of protrusions 203 are provided at both ends of the fusion device body 200 .

[0055] In this embodiment, the reinforcing ribs 3 and the protrusions 203 are also formed as one piece with the entire fusion device body 200 by means of 3D printing. The reinforcing ribs 3 can ensure that the fusion device has a porous structure while also enhancing the internal strength. When the fusion device is implanted, the protrusions 203 can better fit the two ends of the fusion device body to the cervical vertebrae and prevent them from moving.

[0056] In another embodiment of the present invention, Figure 3 and Figure 6 As shown, at least one first filling hole 101 is opened on the outer wall of the tubular member 100, and the loose expansion portion 4 extends into the first filling hole 101 and fills the first filling hole 101; at least one second filling hole 205 is opened on the outer wall of the fusion device body 200, and the loose expansion portion 4 extends into the second filling hole 205 and fills the second filling hole 205.

[0057] In this embodiment, by opening a first filling hole 101 on the cylindrical member 100, opening a second filling hole 205 on the peripheral wall of the fusion body 200, and then filling the first filling hole 101 and the second filling hole 205 with a loose expansion part 4 formed by a single cell structure, and setting a loose expansion part 4 between the cylindrical member 100 and the fusion body 200, the entire fusion device body forms a porous structure, which is conducive to cell adhesion growth, extracellular matrix deposition, nutrition and oxygen entry, metabolic product discharge, and blood vessel and nerve growth, and is a relatively ideal titanium alloy structure. A well-designed porous structure is conducive to reducing the elastic modulus of a solid solid implant and avoiding the "stress shielding" effect of intervertebral fusion. It solves the need to implant autologous bone or allogeneic bone in existing surgeries, as well as the risk of rejection. It solves the effect of upper and lower segment fusion without bone implantation.

[0058] In another embodiment of the present invention, Figure 7 and Figure 8 As shown, the fusion device body 200 is integrally formed and has a first end face and a second end face for docking with the vertebral body, and the mounting hole 204 has at least two inclined mounting holes 204 on the side wall of the fusion device body 200, which are inclined toward the first end face and the second end face respectively, and are used to fix the fusion device body 200 on the vertebra. In the specific implementation, the fusion device body 200 is integrally formed by a front wall 201 and an opposite rear wall 202, and two inclined mounting holes 204 are provided on the front wall 201, and the two mounting holes 204 are inclined toward the two end faces respectively, and the two mounting holes 204 are at an angle of 15-25 degrees with the two end faces of the fusion device body 200.

[0059] In this embodiment, by opening the mounting hole 204, the fusion device is implanted between the upper and lower bones of the cervical vertebrae, and then fixed to the upper bone and the lower bone respectively through the mounting hole 204 by medical fixing screws to ensure that a good fixing effect can be achieved.

[0060] Experiments have shown the elastic modulus and bone ingrowth effect of a PEEK fusion device, a titanium alloy solid fusion device, and a porous structure cervical fusion device printed out of titanium alloy in the present invention.

[0061] 1. Elastic modulus: N / mm

[0062] Titanium alloy solid fusion cage PEEK Fusion Device Fusion device of the present invention Human bones 66593.3 22460.67 18901 12000

[0063] Through comparison of experimental data, it is known that the elastic modulus in this application document is obviously close to the elastic modulus of human bone, and the biocompatibility is good.

[0064] 2. Bone ingrowth:

[0065] Animal experiments have shown that the solid structure and surface have no bone growth or attachment.

[0066] The microporous structure of titanium alloy was determined by CT scanning. The bone ingrowth rate reached about 25% at 6 weeks, and increased over time. It reached about 50% at 24 weeks. Bone density also showed the same characteristics. Over time, the density of new bone became closer and closer to that of bone. Hard slices confirmed the conclusion of CT.

[0067] The CT reconstruction results are as follows Figure 12-14 shown.

[0068] The hard cut results are as follows:

[0069] Hard tissue sections were sliced ​​using the EXAKT E300 slicer and EXAKT E400 CP grinder. Fig.15 As shown (cutting tools and technology: diamond band saw, point contact cutting, cutting speed: 10000mm / sec, minimum thickness of cutting sample: 30um, sample size range: 100mm×90mm×60mm, constant temperature control: circulating cooling water, grinding force: electronic measurement system controls the grinding force, minimum force 1N, sample thickness after grinding: 5-20μm).

[0070] like Figure 16-17 As shown in the data, with the passage of implantation time, there was no significant difference in BV / TV and BMD among S-600, H-600, S-300, and H-300; but with the passage of time, BV / TV and BMD of H-300 increased significantly, indicating that the area of ​​bone ingrowth increased, and the difference was statistically significant.

[0071] It should be noted that the above embodiments can be freely combined as needed. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered as the protection scope of the present invention.

Claims

1. A porous structure fusion device, Features: include A cylindrical member, and a fusion device body sleeved on the cylindrical member; A loose expansion part, which is arranged between the tubular member and the fusion device body and is used to connect the fusion device body and the tubular member; at least two reinforcing ribs, one end of each reinforcing rib being connected to the outer wall of the cylindrical member, and the other end of each reinforcing rib being connected to the inner wall of the fusion device body; Among them, the loose expansion part is a porous structure formed by a number of unit cell structures connected to each other, and the unit cell structure is a double pyramid structure formed by a number of micro rods; and at least one second filling hole is opened on the peripheral wall of the fusion body, and the loose expansion part extends into the second filling hole and fills the second filling hole.

2. A porous structure fusion device according to claim 1, Features: The outer peripheral wall of the cylindrical member is provided with at least one first filling hole.

3. A porous structure fusion device according to claim 2, Features: The loose propped portion extends into the first filling hole and fills the first filling hole.

4. The porous structure fusion device according to claim 1, Features: A plurality of protrusions are formed at both ends of the fusion device body.

5. The porous structure fusion device according to claim 1, Features: The fusion device body is integrally formed and has a first end face and a second end face for docking with the vertebral body, and at least two inclined mounting holes are provided on the side wall of the fusion device body, which are inclined toward the first end face and the second end face respectively, for fixing the fusion device body on the vertebra.

6. The porous structure fusion device according to claim 5, Features: The two mounting holes respectively form an angle of 15-25 degrees with the two end surfaces of the fusion device body.

7. The porous structure fusion device according to claim 1, Features: The micro-rod is a straight rod or a curved rod.

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