Intervertebral fusion cage

Abstract

This invention discloses an interbody fusion device, belonging to the field of orthopedic implant technology. The interbody fusion device includes an inner body with a trabecular bone structure and an outer frame covering the edges of the inner body. The device has a vertical bone graft cavity in its central part, and a bone graft hole communicating with the bone graft cavity is provided on the posterior wall of the device. The upper and lower surfaces of the inner body have covering surfaces at the bone graft cavity that can expand outwards after bone grafting. The interbody fusion device of this invention has an elastic modulus similar to that of human cortical bone, exhibiting good stability and a high bone fusion rate.

Description

Technical Field

[0001] This invention relates to the field of orthopedic implant technology, and in particular to an interbody fusion device. Background Technology

[0002] Intervertebral fusion is an effective treatment for lumbar degeneration and instability. It fuses the upper and lower vertebrae, maintains intervertebral disc height, reduces nerve root pressure, and maintains spinal stability. It has satisfactory clinical results, is easy to perform, and is widely used in the lumbar and cervical spine.

[0003] In recent years, with the promotion of clinical applications and the progress of theoretical research, interbody fusion cages have also been continuously developed. The materials used have evolved from the initial autologous bone graft to titanium metal with better bone ingrowth. However, titanium metal was gradually phased out because it would produce artifacts during surgery and was prone to causing intervertebral collapse after surgery. Then came PEEK (polyether ether ketone) material, which was favored by doctors because it would not produce artifacts and had good biocompatibility. However, it was later found that it was prone to causing non-fusion of the fusion cage.

[0004] Existing technologies disclose various types of interbody fusion devices, such as those with non-adjustable height (e.g., utility model patent application 202021462069.3) and those with adjustable height (e.g., invention patent application 202111496485.4). Research has found that most existing technologies have not addressed or improved the elastic modulus of interbody fusion devices, resulting in a significant difference between the elastic modulus of existing devices and that of human cortical bone. This leads to poor long-term stability and low bone fusion rates. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an intervertebral fusion device with an elastic modulus similar to that of human cortical bone, good stability, and high bone fusion rate.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] An interbody fusion device includes an inner body with trabecular bone structure and an outer frame of solidity covering the edges of the inner body, wherein:

[0008] The interbody fusion device has a vertical bone graft cavity in the middle, and the posterior wall of the interbody fusion device has a bone graft hole that communicates with the bone graft cavity.

[0009] The upper and lower surfaces of the inner body are provided with a covering surface at the bone graft cavity that can expand outward after bone grafting.

[0010] Furthermore, the covering surface is formed by multiple active cells linked together in a chain-like manner.

[0011] Furthermore, the active cells are diamond-shaped cells arranged vertically.

[0012] Furthermore, the diamond morphological cell is a faceted type;

[0013] And / or, the diamond-shaped cell is provided with an O-shaped liner.

[0014] Furthermore, a pressure plate insertion hole is provided at the bone graft hole, and a pressure plate for compressing the bone graft to expand the covering surface is inserted into the pressure plate insertion hole;

[0015] And / or, the inner body includes a plurality of fixed cells, the fixed cells being cubic cells, the cubic cells being arranged vertically along the diagonal of the cube;

[0016] And / or, the front end upper and lower surfaces of the outer frame are provided with plate-shaped fixing teeth extending in the front-rear direction;

[0017] And / or, the upper and lower surfaces of the middle part of the outer frame are provided with plate-shaped fixing teeth extending in the front-to-back direction;

[0018] And / or, the front ends of the outer frame are provided with elastic, fish-fin-shaped fixing teeth that extend outward and backward.

[0019] Furthermore, the outer frame has windows on its sides, and X-shaped cross beams are provided inside the windows, with O-shaped supports on the cross beams.

[0020] Furthermore, the inner body has a protrusion on its side that cooperates with the window, and the cross beam abuts against the outer surface of the protrusion;

[0021] Alternatively, the inner body may have a protrusion on its side that mates with the window, and the protrusion may have a receiving groove for accommodating the cross beam.

[0022] Furthermore, the head end of the interbody fusion device is a bullet shape with four arcs.

[0023] And / or, the upper and lower surfaces of the outer frame are provided with positioning teeth;

[0024] And / or, the intervertebral fusion device is provided with holding grooves on both sides of its rear end.

[0025] Furthermore, the intervertebral fusion device described in the top view is rectangular, isosceles trapezoidal, fan-shaped, or elliptical, wherein:

[0026] The upper and lower surfaces of the interbody fusion device are both inclined planes with different front and rear heights.

[0027] Alternatively, both the upper and lower surfaces of the intervertebral fusion device are arc-shaped, with the middle being higher and the edges lower.

[0028] Furthermore, the interbody fusion device is a 3D printed part;

[0029] And / or, the material of the inner body is titanium alloy, tantalum or niobium-zirconium alloy;

[0030] And / or, the outer frame is made of absorbable glass fiber.

[0031] The present invention has the following beneficial effects:

[0032] The interbody fusion device of this invention combines an inner body with a trabecular bone structure with a solid outer frame covering the edges of the inner body. The product has moderate rigidity and an elastic modulus close to that of human bone, enhancing the long-term stability of the fusion device, reducing or eliminating stress shielding, and the solid outer frame provides good imaging performance. The upper and lower surfaces of the inner body have a covering surface at the bone graft cavity that can expand outwards after bone grafting. The bone graft enters the bone graft cavity through a bone graft hole on the posterior wall of the interbody fusion device. The covering surface can enclose the bone graft to prevent it from falling off, and after expanding, it can fully contact / fit with the vertebral end face, improving the fusion effect. Therefore, the interbody fusion device of this invention has an elastic modulus similar to that of human cortical bone, exhibiting good stability and a high bone fusion rate. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the overall structure of Embodiment 1 of the intervertebral fusion device of the present invention;

[0034] Figure 2 for Figure 1 The diagram shows the exploded structure of the interbody fusion device.

[0035] Figure 3 for Figure 1 A schematic diagram of the structure of a single active cell in the middle covering surface, where (a) is an active cell, (b) is a diamond-shaped cell, and (c) is an O-shaped liner;

[0036] Figure 4 for Figure 1 A schematic diagram of the structure of the active cells in the middle coverage area using chain-like active links;

[0037] Figure 5 for Figure 1 The diagram shows the usage status of the interbody fusion device, where (a) is a sectional view before bone grafting and (b) is a side view after bone grafting.

[0038] Figure 6 This is a schematic diagram of the structure of embodiment 2 of the intervertebral fusion device of the present invention, wherein (a) and (b) are top views, (c) and (d) are side views, and (b) and (d) are structures without fixing teeth;

[0039] Figure 7This is a schematic diagram of the structure of embodiment 3 of the intervertebral fusion device of the present invention, wherein (a) and (b) are top views, (c) and (d) are side views, and (b) and (d) are structures without fixing teeth;

[0040] Figure 8 for Figure 1 A schematic diagram of the fixed cell structure of the main body, where (a) is a structural diagram of a single cubic cell and (b) is a structural diagram of the arrangement of cubic cells;

[0041] Figure 9 This is a schematic diagram of the intervertebral fusion device of the present invention without fixed teeth in embodiment 1, wherein (a) is a top view and (b) is a side view. Detailed Implementation

[0042] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0043] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention 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. Therefore, they should not be construed as limitations on this invention.

[0044] This invention provides an interbody fusion device, such as Figure 1-9 As shown, the structure includes an inner main body 1 with trabecular bone structure and an outer frame 2 that covers the edges (around the periphery) of the inner main body 1, wherein:

[0045] The interbody fusion device has a vertical bone graft cavity 11 in the middle and a bone graft hole 12 connected to the bone graft cavity 11 on the posterior wall of the interbody fusion device.

[0046] The upper and lower surfaces of the inner body 1 are provided with a covering surface 13 at the bone graft cavity 11 (that is, at the upper and lower openings of the bone graft cavity 11) that can be stretched outward after bone grafting.

[0047] During the procedure, the intervertebral fusion device is first used to hold the device and implant it into the patient's intervertebral space. Then, the specific location and condition of the intervertebral fusion device after implantation are clearly observed through imaging equipment. Finally, the position of the intervertebral fusion device is adjusted to reposition the intervertebral disc and bone is grafted into the bone graft cavity 11 through the bone graft hole 12 to make the covering surface 13 open outward, thereby achieving spinal fusion.

[0048] The interbody fusion device of this invention combines an inner body with a trabecular bone structure with a solid outer frame covering the edges of the inner body. The product has moderate rigidity and an elastic modulus close to that of human bone, enhancing the long-term stability of the fusion device, reducing or eliminating stress shielding, and the solid outer frame provides good imaging performance. The upper and lower surfaces of the inner body have a covering surface at the bone graft cavity that can expand outwards after bone grafting. The bone graft enters the bone graft cavity through a bone graft hole on the posterior wall of the interbody fusion device. The covering surface can enclose the bone graft to prevent it from falling off, and after expanding, it can fully contact / fit with the vertebral end face, improving the fusion effect. Therefore, the interbody fusion device of this invention has an elastic modulus similar to that of human cortical bone, exhibiting good stability and a high bone fusion rate.

[0049] The covering surface 13 can take various forms readily conceived by those skilled in the art, such as a biomass film. However, to improve the fusion effect, preferably, such as... Figure 4 As shown, the covering surface 13 is formed by multiple movable cells 14 linked by a chain. At this time, the covering surface 13 has a large range of expansion and can be filled with bone graft to make the upper and lower surfaces completely fit the endplate.

[0050] The active cell 14 can be in various forms, preferably a diamond-shaped cell arranged vertically (e.g., Figure 3 As shown in (b), this design increases the product's resilience, and the protruding tips of the diamond-shaped cells stimulate bone ingrowth, promoting rapid fusion of the intervertebral fusion device with the vertebral body. Specifically, the diamond-shaped cells can be the faceted type shown in the figure, formed by four equally spaced V-shaped edges 141 connected at their upper and lower endpoints. The movable cells 14 of the covering surface 13 can be one or more layers.

[0051] like Figure 3 As shown, the diamond-shaped cell may have an O-shaped liner 142 inside, which greatly enhances the cell's toughness. Specifically, the O-shaped liner 142 can be a three-dimensional O-shaped support formed by the intersection and combination of two O-rings.

[0052] like Figure 2 and Figure 5 As shown, in order to facilitate the expansion of the covering surface 13, a pressure plate insertion hole 121 can be provided at the bone graft hole 12, and a pressure plate 3 for compressing the bone graft to expand the covering surface 13 is inserted into the pressure plate insertion hole 121.

[0053] During use, after the interbody fusion cage is implanted into the patient's intervertebral space and bone is grafted into the bone graft cavity 11, the compression plate 3 is inserted into the compression plate insertion hole 121. The compression plate 3 fully compresses the bone graft in the interbody fusion cage to expand the covering surface 13, thereby allowing the covering surface 13 to... Figure 5 The inward contraction state shown in (a) becomes Figure 5 The outward expansion state shown in (b)

[0054] To securely fix the pressure plate 3, the pressure plate 3 can be snapped into the pressure plate insertion hole 121. For example, its rear end is provided with an elastic locking boss 31 to achieve automatic locking after the pressure plate 3 is inserted.

[0055] The outer frame 2 may have a window 21 on its side, and an X-shaped cross beam 22 is provided inside the window 21. An O-shaped support 23 is provided on the cross beam 22. This unique combination structure of cross beam 22 and O-shaped support 23 effectively increases the support force and toughness, making the intervertebral fusion device structure stable and improving safety.

[0056] To improve the combined strength of the interbody fusion cage, the inner body 1 may have a protrusion 15 on its side that cooperates with the window 21. The cross beam 22 is attached to the outer surface of the protrusion 15. That is to say, the thickness of the cross beam 22 in the lateral direction of the interbody fusion cage can be less than the depth of the window 21 (only located on the outer side of the window 21).

[0057] Alternatively, the side of the inner body 1 may be provided with a boss 15 that mates with the window 21, and the boss 15 may be provided with a receiving groove 151 for accommodating the cross beam 22 (see Figure 2 At this point, the thickness of the cross beam 22 in the lateral direction of the intervertebral fusion device can be the same as the depth of the opening 21, with the cross beam 22 embedded in the entire boss 15; or the thickness of the cross beam 22 can be less than the depth of the opening 21 as shown in the figure (only located on the outer side of the opening 21), with the cross beam 22 only embedded in the outer part of the boss 15.

[0058] The upper and lower surfaces of the middle section and / or the upper and lower surfaces of the front end of the outer frame 2 may be provided with plate-like fixation teeth 24 and 25 extending in the anterior-posterior direction, and the two sides of the front end may be provided with elastic fish-fin-shaped fixation teeth 26 extending outward and backward. These fixation teeth can increase the initial friction and stability of the interbody fusion cage. The fish-fin-shaped fixation teeth 26 on both sides can bend inward due to their own elasticity during implantation, reducing implantation resistance. After reaching the designated position, lateral bone grafting can be performed to increase fixation and anti-retraction function. Specifically, the plate-like fixation teeth 24 and 25 and the fish-fin-shaped fixation teeth 26 may also be omitted depending on the different usage requirements.

[0059] The inner body 1 may include multiple fixed cells 16, which can be of various shapes, such as spheres, tetrahedrons, etc., preferably. Figure 8 The cubic cells shown are arranged vertically along the diagonal of the cube to further increase the product's resilience and stimulate bone ingrowth, thereby improving the bone fusion rate of the fusion device.

[0060] The tip of the interbody fusion device can be a bullet-shaped, four-sided arc, which reduces implantation resistance and ensures a smooth and safe procedure. The upper and lower surfaces of the outer frame 2 can be equipped with positioning teeth 27 (which can be micro-toothed) to increase initial friction and stability of the interbody fusion device. Retrieval slots 28 can be provided on both sides of the rear end of the interbody fusion device for convenient operation.

[0061] Interbody fusion devices can be categorized into cervical spine and lumbar spine products based on their application location. Depending on the product type, the present invention can have the following embodiments:

[0062] Example 1

[0063] like Figure 1-2 As shown in the top view, the intervertebral fusion device is rectangular.

[0064] Example 2

[0065] like Figure 6 As shown, in the top view, the intervertebral fusion device is an isosceles trapezoid or fan-shaped.

[0066] Example 3

[0067] like Figure 7 As shown, the intervertebral fusion device is elliptical in the top view.

[0068] In the above embodiments, the product shape can be adjusted in length, width, and angle according to the implantation location requirements, and can also be divided into different models according to different spinal surgical procedures. The upper and lower surfaces of the interbody fusion device can both be inclined planes with different anterior and posterior heights. Figure 6 In the middle (c) and (d), the front is lower and the back is higher. Figure 7 (c) and (d) are higher in the front and lower in the back, so as to correct the vertebral body and restore the normal physiological curvature; or, the upper and lower surfaces of the interbody fusion device can both be arc-shaped with a higher center and lower edges (i.e., curved surface design in both longitudinal and transverse directions), so as to better fit the end face of the vertebral body and improve stability and bone fusion effect.

[0069] In this invention, the inner body 1 and outer frame 2 of the interbody fusion device can be manufactured separately and then assembled together. For example, the outer frame 2 can be divided into two halves, front and back or left and right, with the inner body 1 inserted into the outer frame 2. However, to facilitate manufacturing and improve overall stability, the interbody fusion device is preferably a 3D printed part, integrally printed. The inner body 1 can be made of metals such as titanium alloy, tantalum, or niobium-zirconium alloy. To prevent poor fusion effect due to a single material, the outer frame 2 can be made of absorbable glass fiber. The fixation teeth (plate-shaped fixation teeth 24 and 25, fin-shaped fixation teeth 26) provided on the outer frame 2 initially play a fixation role, and are gradually absorbed by the patient and repaired as autologous bone in the later stages.

[0070] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An intervertebral cage, comprising: It includes an inner body with trabecular bone structure and an outer frame of solidity covering the edges of the inner body, wherein: The interbody fusion device has a vertical bone graft cavity in the middle, and the posterior wall of the interbody fusion device has a bone graft hole that communicates with the bone graft cavity. The upper and lower surfaces of the inner body are provided with a covering surface at the bone graft cavity that can be expanded outward after bone grafting. The covering surface is formed by multiple movable cells linked by a chain. The bone graft hole is provided with a pressure plate insertion hole, and a pressure plate is inserted into the pressure plate insertion hole to compress the bone graft and expand the covering surface; And / or, the inner body includes a plurality of fixed cells, the fixed cells being cubic cells, the cubic cells being arranged vertically along the diagonal of the cube; And / or, the front end upper and lower surfaces of the outer frame are provided with plate-shaped fixing teeth extending in the front-rear direction; And / or, the upper and lower surfaces of the middle part of the outer frame are provided with plate-shaped fixing teeth extending in the front-to-back direction; And / or, the front ends of the outer frame are provided with elastic, fish-fin-shaped fixing teeth that extend outward and backward.

2. The intervertebral cage of claim 1, wherein, The active cells are diamond-shaped cells arranged vertically.

3. The intervertebral cage of claim 2, wherein, The diamond-shaped cell is a faceted type; And / or, the diamond-shaped cell is provided with an O-shaped liner.

4. The interbody fusion device according to claim 1, characterized in that, The outer frame has windows on its sides, and X-shaped cross beams are provided inside the windows. O-shaped supports are provided on the cross beams.

5. The interbody fusion device according to claim 4, characterized in that, The inner body has a protrusion on its side that matches the window, and the cross beam abuts against the outer surface of the protrusion. Alternatively, the inner body may have a protrusion on its side that mates with the window, and the protrusion may have a receiving groove for accommodating the cross beam.

6. The interbody fusion device according to claim 1, characterized in that, The head end of the interbody fusion device is a bullet shape with four arcs. And / or, the upper and lower surfaces of the outer frame are provided with positioning teeth; And / or, the intervertebral fusion device is provided with holding grooves on both sides of its rear end.

7. The interbody fusion device according to claim 1, characterized in that, The intervertebral fusion cage shown in the top view is rectangular, isosceles trapezoidal, fan-shaped, or elliptical, wherein: The upper and lower surfaces of the interbody fusion device are both inclined planes with different front and rear heights. Alternatively, both the upper and lower surfaces of the intervertebral fusion device are arc-shaped, with the middle being higher and the edges lower.

8. The interbody fusion device according to any one of claims 1-7, characterized in that, The interbody fusion device is a 3D printed part; And / or, the material of the inner body is titanium alloy, tantalum or niobium-zirconium alloy; And / or, the outer frame is made of absorbable glass fiber.

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