A mechanically adaptive intervertebral fusion cage with variable stiffness

Abstract

The present application provides a mechanically adaptive intervertebral fusion device with variable stiffness, comprising: a deformable structure group and two plates, the deformable structure assembly being disposed between the two plates, the two plates having a critical point spacing value, and when the spacing between the two plates is greater than the critical point spacing value, the multiple structural portions of the deformable structure group are separated, the deformable structure group having a first stiffness, and when the spacing between the two plates is less than or equal to the critical point spacing value, the deformable structure group deforms, some structural portions of the deformable structure group abut against each other, and the mechanically adaptive intervertebral fusion device having a second stiffness, wherein the second stiffness is greater than the first stiffness. The fusion device of the present application can adapt to the internal mechanical environment by changing its own stiffness, exhibiting a lower stiffness when responding to low loads and a higher stiffness when subjected to high loads, thereby improving the mechanical compatibility with adjacent vertebrae, optimizing mechanical load transfer, reducing adjacent vertebral collapse, and promoting vertebral fusion.

Description

Technical Field

[0001] The present application relates to the field of medical devices, and in particular to a mechanically adaptive intervertebral fusion device with variable stiffness. Background Art

[0002] Intervertebral disc degeneration is a common and frequently occurring condition and a cause of low back pain. It most commonly affects people aged 20 to 40, with a prevalence of 37% in those aged 20 and 96% in those aged 80. Intervertebral fusion is an important surgical treatment for spinal degeneration. Intervertebral fusion cages are currently primarily made of biocompatible titanium alloys or the polymer PEEK. They are filled with bone graft to promote fusion of the upper and lower vertebrae. Postoperatively, they not only reduce pressure but also maintain intervertebral height and physiologic curvature of the cervical spine. Existing studies have shown that the use of intervertebral fusion cages for surgical fusion and intervertebral height restoration can relieve compression and support intervertebral height, achieving good clinical results. As a key device used in intervertebral fusion surgery, intervertebral fusion cages primarily restore intervertebral height and physiologic curvature, while also bearing the load, thereby promoting bony fusion and reducing the risk of complications.

[0003] Initially, the intervertebral fusion device was cylindrical in shape. However, due to its many shortcomings in clinical practice, such as small contact area with the endplates, small amount of bone graft, inability to maintain intervertebral height, and easy sinking of the device, it has basically withdrawn from the clinical market. Subsequently, the cubic intervertebral fusion device emerged, which is currently the most commonly used intervertebral fusion device in clinical practice. The cubic intervertebral fusion device has a large bone graft space and a strong load capacity, but its resistance to rotational stress and self-stabilization performance are poor. In order to improve the self-stabilization performance of the cubic intervertebral fusion device, a self-locking intervertebral fusion device has been used clinically, such as the MC+ and ROI-C intervertebral fusion devices from the French company LDR. This fusion device consists of an outer PEEK material box and a titanium alloy bone anchor plate. The bone graft can be placed in the center of the box. After implantation, the titanium alloy clip below will be embedded in the lower vertebral body (ROI is embedded in the upper and lower vertebral bodies). Clinical studies have shown that this self-locking intervertebral fusion device achieves excellent bony fusion, but 9% of patients still experience device subsidence into the underlying vertebra. In summary, the intervertebral fusion devices currently available on the market are poorly matched to patients and offer suboptimal therapeutic outcomes. In clinical practice, adjacent vertebral collapse, degeneration, and fractures are common, requiring secondary revision surgeries in severe cases, causing significant pain for patients.

[0004] The spine serves as the support for the trunk, transmitting the weight of the head and trunk to the pelvis, allowing the trunk to undergo adequate three-dimensional physiological movements, such as extension, flexion, and axial rotation. When standing in the anatomical position, the pressure on the intervertebral discs far exceeds the weight of the upper body. When sitting, the pressure on the lumbar discs is more than three times that of the trunk. Movements such as jumping can exert loads on the intervertebral discs that are more than twice that of the static position. Flexion, extension, and lateral flexion of the spine can generate extension stresses in certain areas of the intervertebral discs. Axial torsion of the trunk also generates shear loads on the intervertebral discs. Therefore, the pressure on the intervertebral discs is a time-varying composite of extension, compression, and shear. After implantation, an intervertebral fusion cage replaces the intervertebral disc. Its interface with the adjacent vertebrae withstands and transmits the complex mechanical loads of the body. Currently available intervertebral fusion cages have a constant stiffness, which is poorly matched to the complex mechanical environment of the body. This makes it impossible to achieve optimal load transfer during human motion. This results in poor mechanical compatibility between the cage and the adjacent vertebrae, leading to clinical problems such as collapse, degeneration, and fracture of adjacent vertebral segments.

[0005] In view of this, this application is hereby filed. Summary of the Invention

[0006] In order to solve one of the above technical problems, the present invention provides a mechanically adaptive intervertebral fusion cage with variable stiffness.

[0007] The present invention adopts the following technical solutions:

[0008] A mechanically adaptive intervertebral fusion cage with variable stiffness, comprising:

[0009] Two plates, the two plates are spaced apart, the spacing between the first ends of the two plates is smaller than the spacing between the second ends of the two plates, a plurality of convex racks are provided on a side of the plate facing away from the deformable structure group, the convex racks are sequentially arranged along the length direction of the plate, and the convex racks extend along the width direction of the plate;

[0010] A deformable structure group, wherein the deformable structure component is arranged between the two plates;

[0011] The two plates have a critical point spacing value. When the spacing between the two plates is greater than the critical point spacing value, the multiple structural parts of the deformable structural group are separated, and the deformable structural group has a first stiffness. When the spacing between the two plates is less than or equal to the critical point spacing value, the deformable structural group is deformed, and some structural parts of the deformable structural group abut against each other, and the mechanically adaptive intervertebral fusion cage has a second stiffness.

[0012] Wherein, the second stiffness is greater than the first stiffness.

[0013] Optionally, the plate body and the deformable structure group are integrally formed, and when the two plates are brought closer together, part of the structure of the deformable structure group moves toward each other along the arrangement direction of the two plates until they abut against each other;

[0014] And / or, when the two plates are approaching each other, part of the structural parts of the deformation structure group moves toward each other along a direction perpendicular to the arrangement of the two plates until they collide with each other.

[0015] Optionally, among the structural parts, at least some of the adjacent structural parts have undercut structures formed by being recessed toward each other;

[0016] When the distance between the two plates is greater than the critical point distance value, there is a gap between the undercut structures of adjacent structural parts;

[0017] When the distance between the two plates is equal to or less than the critical point distance value, the undercut structures of adjacent structural parts offset each other.

[0018] Optionally, the undercut structure includes a first inclined portion and a second inclined portion;

[0019] There is an included angle between the first inclined portion and the second inclined portion;

[0020] One end of the first inclined portion and the second inclined portion are connected to form an abutment portion, and the other end of the first inclined portion and the second inclined portion are separated;

[0021] When the distance between the two plates is greater than the critical point distance value, the abutment parts of the adjacent structural parts are separated;

[0022] When the distance between the two plates is less than or equal to the critical point distance value, at least some of the adjacent structural parts abut against each other.

[0023] Optionally, a plurality of undercut structures are provided on each of the structural parts, and the undercut structures are sequentially arranged along the arrangement direction of the two plates;

[0024] At least some of the undercut structures on adjacent structural parts correspond to each other in position;

[0025] When the distance between the two plates is greater than the critical point distance value, each of the opposite undercut structures on the adjacent structural parts has a gap;

[0026] When the distance between the two plates is less than or equal to the critical point distance value, the abutting tops of the opposite undercut structures on the adjacent structural parts abut against each other.

[0027] Optionally, adjacent undercut structures in each of the undercut structures on each of the structural portions are recessed in different directions;

[0028] When the distance between the two plates is less than or equal to the critical point distance value, two adjacent undercut structures on the structural portion are offset against corresponding undercut structures on the structural portions on both sides.

[0029] Optionally, a connecting beam is connected between two adjacent structural parts.

[0030] Optionally, the two undercut structures in two adjacent structural portions, which are at least partially recessed in directions away from each other, are connected by the connecting beam.

[0031] Optionally, the structural portion is in any one of a sheet-like shape, a strip-like shape, and a three-dimensional structure formed by connecting a plurality of strips.

[0032] Optionally, the structural parts are arranged sequentially along the length direction of the plate;

[0033] Alternatively, the structural parts are arranged along the length direction and width direction of the plate body, and when the distance between the two plates is greater than the critical point distance value, adjacent structural parts have a gap along the length direction of the plate body, and adjacent structural parts have a gap along the width direction of the plate body; when the distance between the two plates is less than or equal to the critical point distance value, several adjacent structural parts offset each other along the length direction of the plate body, and several adjacent structural parts offset each other along the width direction of the plate body.

[0034] By adopting the above technical solution, this application has the following beneficial effects:

[0035] The fusion device of the present application can adapt to the mechanical environment in the body by changing its own stiffness. It can exhibit lower stiffness when responding to low loads and higher stiffness when subjected to high loads, thereby improving the mechanical adaptability with adjacent vertebrae, optimizing mechanical load transfer, reducing adjacent vertebral collapse, and promoting vertebral fusion.

[0036] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings are part of this application and are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but do not constitute an undue limitation of the present invention. Obviously, the drawings described below are only some embodiments. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without inventive effort. In the accompanying drawings:

[0038] Figure 1 A side view of a first mechanically adaptive intervertebral fusion cage with variable stiffness provided by an embodiment of the present application is shown;

[0039] Figure 2 A three-dimensional perspective view of a first mechanically adaptive intervertebral fusion cage with variable stiffness provided by an embodiment of the present application is shown;

[0040] Figure 3 A three-dimensional perspective view of a second mechanically adaptive intervertebral fusion cage with variable stiffness provided by an embodiment of the present application is shown;

[0041] Figure 4 Another stereoscopic view of the third mechanically adaptive intervertebral fusion cage with variable stiffness provided by an embodiment of the present application is shown;

[0042] Figure 5 Shown Figure 4 A side view of a third variable stiffness mechanically adaptive interbody fusion cage is shown;

[0043] Figure 6 Shown Figure 4 A front view of a third variable stiffness mechanically adaptive interbody fusion cage is shown;

[0044] Figure 7 A schematic structural diagram of a fourth deformable structure group of a mechanically adaptive intervertebral fusion cage with variable stiffness provided by an embodiment of the present disclosure is shown;

[0045] Figure 8 A diagram showing a state in which a fourth mechanically adaptive intervertebral fusion cage with variable stiffness provided by an embodiment of the present disclosure is implanted into a vertebral body;

[0046] Figure 9 A schematic structural diagram of a deformable structure group of a fifth mechanically adaptive intervertebral fusion cage with variable stiffness provided by an embodiment of the present disclosure is shown;

[0047] Figure 10 A diagram showing a state in which a fifth mechanically adaptive intervertebral fusion cage with variable stiffness provided by an embodiment of the present disclosure is implanted into a vertebral body;

[0048] Figure 11 A schematic structural diagram of a sixth deformable structure group of a mechanically adaptive intervertebral fusion cage with variable stiffness provided by an embodiment of the present disclosure is shown;

[0049] Figure 12 A schematic structural diagram of a deformable structure group of a seventh mechanically adaptive intervertebral fusion cage with variable stiffness provided by an embodiment of the present disclosure is shown.

[0050] In the figure: 100, intervertebral fusion cage; 1, plate; 2, deformable structure group; 21, structure part; 21a, through hole; 211, undercut structure; 211a, first inclined part; 211b, second inclined part; 211c, abutment top; 22, connecting beam; 200, cone.

[0051] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but rather to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0053] In the description of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0054] In the description of the present invention, it should be noted that, unless otherwise specified or limited, the terms "mounted" and "connected" should be understood broadly. For example, they can refer to fixed, detachable, or integral connections; mechanical or electrical connections; and direct or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0055] See also Figures 1 to 12As shown, the present application provides a mechanically adaptive intervertebral fusion device 100 with variable stiffness, comprising: two plates 1 and a deformable structure group 2. The two plates 1 are spaced apart, and the spacing between the first ends of the two plates 1 is smaller than the spacing between the second ends of the two plates 1. A plurality of convex racks are provided on the side of the plate 1 facing away from the deformable structure group. Each of the convex racks is sequentially arranged along the length direction of the plate 1, and the convex racks extend along the width direction of the plate 1. The two plates 1 are used to cooperate with the upper and lower vertebrae respectively. The deformable structure group 2 is arranged between the two plates 1. The deformable structure group 2 can have multiple structural parts 21, and each structural part 21 can be connected to each other or independent of each other. Each structural part 21 can also be partially connected and partially independent. During the relative movement of the two plates 1, each structural part 21 can move relative to each other and change position. The two plates 1 have a critical point spacing value. When the spacing between the two plates 1 is greater than the critical point spacing value, the multiple structural portions 21 of the deformable structural group 2 separate, and the deformable structural group 2 has a first stiffness. When the spacing between the two plates 1 is less than or equal to the critical point spacing value, the deformable structural group 2 deforms, at least some of the structural portions 21 of the deformable structural group abut against each other, and the mechanically adaptive intervertebral fusion cage has a second stiffness. The second stiffness is greater than the first stiffness.

[0056] It should be noted that the first stiffness and the second stiffness can be a single value or a range.

[0057] The surgeon can use a clamp to implant the intervertebral fusion cage 100 provided in the present application between the cones 200 inside the human body, and can implant nails and rods on the outside of the vertebral bodies 200 to fix the cones and achieve a stabilizing effect. Figure 8 and Figure 10 The diagrams respectively illustrate the states of two intervertebral fusion cages 100 provided in the embodiments of the present application being implanted into a vertebral body 200 .

[0058] The fusion device of the present application can adapt to the mechanical environment in the body by changing its own stiffness. It can exhibit lower stiffness when responding to low loads and higher stiffness when subjected to high loads, thereby improving the mechanical adaptability with adjacent vertebrae, optimizing mechanical load transfer, reducing adjacent vertebral collapse, and promoting vertebral fusion.

[0059] In some possible implementations, see Figure 7 、 Figure 11 and Figure 12As shown, the plate body and the deformable structure group are integrally formed. When the two plate bodies 1 approach each other, a part of the structural portion 21 of the deformable structure group (the position indicated by the number 211) moves toward each other along the arrangement direction of the two plate bodies 1 (such as the up and down direction), that is, it moves roughly along the thickness direction of the plate body 1 until they collide with each other, thereby causing a sudden change in the stiffness of the intervertebral fusion cage to facilitate bearing high loads.

[0060] In some possible implementations, see Figures 1 to 6 as well as Figure 9 As shown, when the two plates 1 approach each other, the partial structural portion 21 of the deformation structure group moves toward each other along the arrangement direction perpendicular to the two plates 1, that is, moves roughly along the length direction of the plates 1 until they collide with each other.

[0061] See also Figure 7 As shown, during the process of the two plates 1 approaching each other, the partial structural portion 21 of the deformable structural group (indicated by the position numeral 211) moves toward each other along the arrangement direction of the two plates 1 (e.g., the vertical direction) until they abut against each other. The partial structural portion 21 of the deformable structural group moves toward each other perpendicular to the arrangement direction of the two plates 1, that is, moves approximately along the length direction of the plates 1 until they abut against each other.

[0062] When the intervertebral fusion cage is subjected to low loads, the numerous structural components 21 of the deformable structural group have gaps between them and are not in contact. The entire intervertebral fusion cage has low elasticity and is easily deformed, resulting in a low reaction force on the vertebral middle plate. However, if the patient lifts heavy objects, the intervertebral fusion cage is subjected to greater forces, and the two plates 1 move closer together until the numerous structural components 21 contact each other. This causes the intervertebral fusion cage's stiffness to increase dramatically, significantly improving its support performance.

[0063] In some possible embodiments, in each of the structural portions 21, at least some adjacent structural portions 21 have side concave structures 211 that are recessed toward each other. When the distance between the two plate bodies 1 is greater than the critical point spacing value, there is a gap between the side concave structures 211 of adjacent structural portions 21. When the distance between the two plate bodies 1 is equal to or less than the critical point spacing value, the side concave structures 211 of adjacent structural portions 21 offset each other.

[0064] The undercut structure 211 itself is not straight and is susceptible to deformation when subjected to force. When the undercut structure 211 is extended in the first direction as a whole, and a compressive force is applied to its ends, the undercut structure 211 may bulge in the second direction. In other words, when the undercut structure 211 is subjected to an external force in the first direction, it will significantly deform and move in the second direction. The first and second directions can be perpendicular. One of the first and second directions can be the thickness direction of the plate 1, and the other can be the length direction of the plate 1.

[0065] In some possible implementations, see Figure 1 As shown, the undercut structure 211 includes a first inclined portion 211a and a second inclined portion 211b, wherein the first inclined portion 211a and the second inclined portion 211b have an included angle therebetween. One end of the first inclined portion 211a and the second inclined portion 211b are connected to form an abutment portion 211c, and the other ends of the first inclined portion 211a and the second inclined portion 211b are separated. When the distance between the two plates 1 is greater than the critical point distance value, the abutment portions 211c of the adjacent structural portions 21 are separated. When the distance between the two plates 1 is less than or equal to the critical point distance value, the abutment portions 211c of at least some adjacent structural portions 21 abut against each other. The first inclined portion 211a and the second inclined portion 211b can be straight structures, arc-shaped structures, etc., and this application does not limit the specific structure of the inclined portion.

[0066] It should be noted that when the distance between the two plates 1 is less than or equal to the critical point distance value, the structural parts 21 can be offset in pairs, that is, the structural parts 21 can be offset in pairs, or multiple structural parts 21 can be in contact with each other.

[0067] In some possible implementations, see Figures 4 to 6 As shown, a plurality of undercut structures 211 are provided on each of the structural portions 21, and the undercut structures 211 are sequentially arranged along the arrangement direction of the two plate bodies 1, and at least some of the undercut structures 211 on adjacent structural portions 21 correspond one to one. When the spacing between the two plate bodies 1 is greater than the critical point spacing value, the relative undercut structures 211 on the adjacent structural portions 21 have gaps. When the spacing between the two plate bodies 1 is less than or equal to the critical point spacing value, the abutting top portions 211c of the relative undercut structures 211 on the adjacent structural portions 21 abut against each other.

[0068] These structures can be independent and connected to the plates 1, or they can be interconnected to form a complex, integrated structure. When the distance between the two plates 1 is large, multiple undercut structures 211 can be provided on the structural portion 21. The structural portion 21 can be roughly wavy, with its ends connected to the two plates 1. Providing more undercut structures 211 on the structural portion 21 can help increase the stability of the intervertebral fusion cage.

[0069] Specifically, adjacent undercut structures 211 within each structural portion 21 are recessed in different directions. When the distance between the two plates 1 is less than or equal to the critical distance, two adjacent undercut structures 211 on the structural portion 21 abut against corresponding undercut structures 211 on the structural portions 21 on either side. By recessing adjacent undercut structures 211 in different directions, the density of the effective abutment portions 211c is increased, thereby enhancing the stability of the intervertebral fusion cage, extending its service life, and improving its reliability.

[0070] In some possible implementations, see Figure 5 、 Figure 6 and Figure 11 A connecting beam 22 is connected between two adjacent structural parts 21. Thus, the various structures are connected to form an integral structure, making the deformation of the deformable structure controllable, preventing the deformable structure group 2 from deforming too much in the length direction of the plate body 1, and further improving the stability of the deformable structure group 2.

[0071] Specifically, the two undercut structures 211 of two adjacent structural portions 21, at least partially recessed in a direction away from each other, are connected by the connecting beam 22. The distance between the abutting tops 211c of the two undercut structures 211 recessed in a direction away from each other is relatively large, making each of the two structures suitable for installing a connecting beam 22. The connecting beam 22 is connected to the recessed side of the abutting top 211c, without affecting the abutting engagement between the abutting top 211c and the corresponding abutting top 211c of the adjacent structural portion 21.

[0072] In some possible embodiments, the structural portion 21 is in the form of a sheet, a strip, or a three-dimensional structure formed by connecting multiple strips. The structural body of the present application can have various shapes, and the specific structural shape of the structural portion 21 is not limited in this application. When the structural body 21 is in the form of a sheet, a through hole 21a can be provided in the structural body 21.

[0073] In some possible implementations, see Figures 4 to 6 As shown, each of the structural parts 21 is sequentially arranged along the length direction of the plate body 1, or each of the structural parts 21 is arranged along the length direction and width direction of the plate body 1. When the distance between the two plates 1 is greater than the critical point distance value, see Figure 5 As shown, there is a gap between adjacent structural parts 21 along the length direction of the plate body 1, see Figure 6 As shown, there is a gap between adjacent structural parts 21 along the width direction of the plate body 1. When the distance between two plates 1 is less than or equal to the critical point distance value, several adjacent structural parts 21 along the length direction of the plate body 1 offset each other, and several adjacent structural parts 21 along the width direction of the plate body 1 offset each other.

[0074] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with this patent can make slight changes or modifications to equivalent embodiments using the above-mentioned technical contents without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the solution of the present invention.

Claims

1. A mechanically adaptive intervertebral fusion cage with variable stiffness, characterized in that: include: Two plates, the two plates are spaced apart, the spacing between the first ends of the two plates is smaller than the spacing between the second ends of the two plates, a plurality of convex racks are provided on a side of the plate facing away from the deformable structure group, the convex racks are sequentially arranged along the length direction of the plate, and the convex racks extend along the width direction of the plate; A deformable structure group, wherein the deformable structure group is arranged between the two plates, the plates and the deformable structure group are integrally formed, the deformable structure group has a plurality of structural parts, and when the two plates are approaching each other, some of the structural parts of the deformable structure group move toward each other along the arrangement direction perpendicular to the two plates until they abut each other, and a plurality of undercut structures are provided on each of the structural parts, and the undercut structures on each of the structural parts are arranged in sequence along the arrangement direction of the two plates, and adjacent undercut structures are respectively recessed in different directions, and two undercut structures of the adjacent structural parts that are at least partially recessed in the direction away from each other are connected by a connecting beam; The two plates have a critical point spacing value. When the spacing between the two plates is greater than the critical point spacing value, the multiple structural parts of the deformable structural group are separated, and the deformable structural group has a first stiffness. When the spacing between the two plates is less than or equal to the critical point spacing value, the deformable structural group deforms, and the undercut structural parts of at least some adjacent structural parts abut against each other, and the mechanically adaptive intervertebral fusion cage has a second stiffness. Wherein, the second stiffness is greater than the first stiffness.

2. The mechanically adaptive intervertebral fusion cage with variable stiffness according to claim 1, characterized in that: The undercut structure comprises a first inclined portion and a second inclined portion; There is an included angle between the first inclined portion and the second inclined portion; One end of the first inclined portion and the second inclined portion are connected to form an abutment portion, and the other end of the first inclined portion and the second inclined portion are separated; When the distance between the two plates is greater than the critical point distance value, the abutting tops of the adjacent structural parts are separated; When the distance between the two plates is less than or equal to the critical point distance value, at least some of the adjacent structural parts abut against each other.

3. The mechanically adaptive intervertebral fusion cage with variable stiffness according to claim 1, characterized in that: When the distance between the two plates is less than or equal to the critical point distance value, two adjacent undercut structures on the structural portion are offset against corresponding undercut structures on the structural portions on both sides.

4. The mechanically adaptive intervertebral fusion cage with variable stiffness according to any one of claims 1 to 3, characterized in that: The structure part is in any one of sheet and strip shape.

5. The mechanically adaptive intervertebral fusion cage with variable stiffness according to any one of claims 1 to 3, characterized in that: The structural part is a three-dimensional structure formed by connecting a plurality of strips.

6. The mechanically adaptive intervertebral fusion cage with variable stiffness according to any one of claims 1 to 3, characterized in that: The structural parts are arranged in sequence along the length direction of the plate body.

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