Spine fusion cage

Abstract

The invention discloses a spinal fusion cage, and relates to the technical field of medical instruments, the spinal fusion cage comprises a base body, the base body is used for being supported in an intervertebral space, the base body comprises a first side and a second side which are opposite, the first side and the second side are both provided with a plurality of deformation parts which are distributed side by side in the horizontal direction, and the deformation parts are vertically supported on the upper side and the lower side of the base body; and each deformation part can deform along with the height change of the intervertebral space so as to support the intervertebral space. According to the spinal fusion cage, the stability of the postoperative lumbar vertebra structure and the bone healing effect are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and particularly to a spinal fusion device. Background Art

[0002] Traditional spinal fusion surgeries achieve intervertebral bony fusion by implanting rigid fusion devices (such as PEEK polyetheretherketone or titanium alloy fusion devices). Although they can stabilize spinal segments in the short term, their static mechanical properties have significant limitations: the rigid support causes the load to be overly concentrated at the fusion device - bone interface, triggering the stress shielding effect, inhibiting the surrounding bone reconstruction, increasing the risk of fusion failure and adjacent segment degeneration; in addition, completely restricting segmental micro - motion may weaken the physiological load conduction of the spine, affect the biological environment for bone healing, and lead to the formation of pseudoarthrosis.

[0003] Existing improved dynamic fusion devices (such as the design with a gradually changing elastic modulus) attempt to disperse stress through local deformation, but still face the problem of insufficient mechanical adaptability, or face the mismatch between the dynamic range and the physiological movement of the spine, accelerating fatigue fracture, or face insufficient micro - motion regulation accuracy, making it difficult to balance the contradiction between "the stability required for bone healing" and "the protection of adjacent segments". Summary of the Invention

[0004] The purpose of the present invention is to provide a spinal fusion device to solve the problems existing in the above - mentioned prior art and improve the stability of the postoperative lumbar spine structure and the bone healing effect.

[0005] To achieve the above - mentioned purpose, the present invention provides the following solution:

[0006] The present invention provides a spinal fusion device, including a base body. The base body is used to support the intervertebral space. The base body includes opposite first and second sides. A plurality of deformation components arranged side by side in the horizontal direction are provided on both the first side and the second side. Each deformation component vertically supports the upper and lower sides of the base body, and each deformation component can deform with the change of the height of the intervertebral space to enable support.

[0007] Preferably, the base body includes an upper cover plate, a lower cover plate, an intermediate support, and two side support members respectively disposed on the first side and the second side. The intermediate support is disposed between the upper cover plate and the lower cover plate, and the two side support members are respectively disposed on opposite sides of the intermediate support; each deformation component is disposed inside the corresponding side support member, and both ends of each deformation component are respectively connected to the upper cover plate and the lower cover plate.

[0008] Preferably, the upper cover plate, the lower cover plate, and the side support members are all made of titanium alloy material, and the intermediate support is made of PEEK material.

[0009] Preferably, an intermediate layer is provided between the edge of the upper cover plate and the upper ends of the two side supports. Each of the deformation components passes through the intermediate layer and is connected to the upper cover plate. The intermediate layer is made of PEEK material.

[0010] Preferably, the sides of the upper cover plate and the lower cover plate that are used to contact the vertebral endplate are provided as porous surfaces.

[0011] Preferably, a reinforcing layer is provided at the fitting interface between the intermediate support and the upper cover plate, the lower cover plate, and the side supports.

[0012] Preferably, a bone grafting window, an observation window, and an operating opening for surgical forceps are provided on the base body.

[0013] Preferably, the edges of the base body and each of the deformation components are provided as rounded corners; and marking points for imaging and positioning are provided on the edge of the base body.

[0014] Preferably, each of the deformation components is provided as a scissor-type telescopic component. The side support has a sandwich layer, and the scissor-type telescopic component is disposed in the corresponding sandwich layer of the side support; wear-resistant bushings are provided at each hinge of the scissor-type telescopic component; the scissor-type telescopic component can deform as the height of the intervertebral space changes to provide non-linear support in the vertical direction.

[0015] Preferably, each of the deformation components is provided as an elastic member. The side support includes a support wall and a plurality of sleeves. The plurality of sleeves are provided corresponding to the plurality of deformation components. Each sleeve has a side opening and is connected to the support wall to enclose an accommodation cavity capable of accommodating the corresponding deformation component; the elastic member can deform as the height of the intervertebral space changes to provide dynamic support.

[0016] The present invention has achieved the following technical effects compared with the prior art:

[0017] The spinal fusion device provided by the present invention places the base body in the intervertebral space for support and fusion. Since a plurality of deformation components arranged side by side are provided on both the relatively first side and the second side of the base body, each deformation component can deform as the height of the intervertebral space changes to enable adaptive support; and the plurality of deformation components are distributed at multiple positions, and can provide appropriate height changes when the height of the intervertebral space changes, so as to realize the height self-adaptation of different parts of the fusion device, reduce the risk of adjacent joint degeneration, improve the stability of the postoperative lumbar spine structure and the bone healing effect; and according to the biomechanical environment of the postoperative lumbar spine structure, by adjusting the parameters of the corresponding deformation component, the support performance of the corresponding part can be adjusted personalized, further reducing the risk of adjacent joint degeneration and improving the stability of the postoperative lumbar spine structure and the bone healing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0019] Figure 1 Axial schematic diagram of the spinal fusion device provided for Embodiment 1;

[0020] Figure 2 Explosion schematic diagram of the spinal fusion device provided for Embodiment 1;

[0021] Figure 3 Structural schematic diagram of the scissor-type telescopic component provided for Embodiment 1;

[0022] Figure 4 Schematic diagram of the application state model of the spinal fusion device provided for Embodiment 1;

[0023] Figure 5 Explosion schematic diagram of the spinal fusion device provided for Embodiment 2.

[0024] In the figure: 1 - matrix; 11 - first side; 12 - second side; 13 - upper cover plate; 14 - lower cover plate; 15 - intermediate support; 16 - side support member; 161 - interlayer; 162 - support wall; 163 - sleeve; 17 - intermediate layer; 18 - bone graft window; 19 - observation window; 20 - surgical forceps operation port; 2 - deformation component; 21 - scissor-type telescopic component; 22 - elastic member; 3 - L4 cortical bone; 4 - surgical endoscope channel; 5 - annulus fibrosus; 6 - titanium rod; 7 - pedicle screw. Detailed implementation manners

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0026] The purpose of the present invention is to provide a spinal fusion device to solve the problems existing in the above-mentioned prior art and improve the stability of the postoperative lumbar spine structure and the bone healing effect.

[0027] To make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the drawings and specific implementation manners.

[0028] Embodiment 1

[0029] This embodiment provides a spinal fusion device. Please refer to Figure 1 , Figure 2 and Figure 3 . It includes a base body 1, which is used to support the intervertebral space. The base body 1 includes opposite first side 11 and second side 12. A plurality of deformation components 2 arranged side by side in the horizontal direction are provided on both the first side 11 and the second side 12. Each deformation component 2 is vertically supported on the upper side and the lower side of the base body 1, and each deformation component 2 can deform as the height of the intervertebral space changes, so as to be able to provide support.

[0030] The working principle of the spinal fusion device provided in this embodiment is as follows:

[0031] The base body 1 is placed in the intervertebral space for support and fusion. Since a plurality of deformation components 2 arranged side by side are provided on both the opposite first side 11 and second side 12 of the base body 1, each deformation component 2 can deform vertically as the height of the intervertebral space changes, so as to be able to perform adaptive adjustment of the vertical stiffness; and a plurality of deformation components 2 are distributed at multiple positions, which can provide appropriate height changes when the height of the intervertebral space changes, so as to achieve height adaptability of different parts of the fusion device, reduce the risk of adjacent joint degeneration, and improve the stability of the postoperative lumbar spine structure and the bone healing effect; and according to the biomechanical environment of the postoperative lumbar spine structure, by adjusting the parameters of the corresponding deformation component 2, the support performance of the corresponding part can be adjusted personalized, further reducing the risk of adjacent joint degeneration and improving the stability of the postoperative lumbar spine structure and the bone healing effect.

[0032] In an optional solution of this embodiment, preferably, the base body 1 includes an upper cover plate 13, a lower cover plate 14, an intermediate support 15, and two side support members 16 respectively disposed on the first side 11 and the second side 12. The intermediate support 15 is disposed between the upper cover plate 13 and the lower cover plate 14, and the two side support members 16 are respectively disposed on opposite sides of the intermediate support 15; each deformation component 2 is disposed inside the corresponding side support member 16, and both ends of each deformation component 2 are respectively connected to the upper cover plate 13 and the lower cover plate 14; wherein, the upper cover plate 13 and the lower cover plate 14 are in contact connection with the end plates of the intervertebral space, the intermediate support 15 can provide support, and the side support members 16 can play a role in protecting the deformation components 2; the height change of the intervertebral space acts on each deformation component 2 through the upper cover plate 13 and the lower cover plate 14, so that each deformation component 2 performs adaptive deformation support.

[0033] In an alternative embodiment of the present invention, preferably, the upper cover plate 13, the lower cover plate 14 and the side support members 16 are all made of titanium alloy, and the intermediate support 15 is made of PEEK material; the use of titanium alloy for the upper cover plate 13 and the lower cover plate 14 has better biocompatibility, which is beneficial to bone reconstruction after implantation. The PEEK matrix can ensure that the fusion device has sufficient height on the premise of sufficient initial stiffness, while avoiding the stress shielding effect; the PEEK material is polyetheretherketone material with an elastic modulus of 3-4 GPa; by using the titanium alloy and PEEK composite material, it can ensure that the fusion device has sufficient height on the premise of sufficient initial stiffness, and can make the initial stiffness of the fusion device close to that of human cortical bone, promoting bone healing; at the same time, on the premise of maximizing the good biocompatibility of titanium alloy, the stress shielding phenomenon easily occurring in pure titanium fusion devices is avoided.

[0034] In an alternative embodiment of the present invention, preferably, an intermediate layer 17 is provided between the edge of the upper cover plate 13 and the upper ends of the two side support members 16. Each deformation member 2 passes through the intermediate layer 17 and is connected to the upper cover plate 13. The intermediate layer 17 is made of PEEK material; that is, the edge of the upper cover plate 13 and the two side support members 16 are not directly connected, but are connected through the intermediate layer 17 made of PEEK material. By avoiding the direct connection between the upper cover plate 13 made of titanium alloy and the two side support members 16, the stress shielding phenomenon easily occurring in pure titanium fusion devices is avoided; the intermediate layer 17 can be directly integrated with the intermediate support 15, that is, the protruding parts on both sides of the upper end of the intermediate support 15 are the intermediate layer 17, or the intermediate layer 17 can be arranged in a ring shape and pressed between the upper cover plate 13 and the intermediate support 15.

[0035] In addition, each deformation member 2 passes through the intermediate layer 17 and is connected to the upper cover plate 13, that is, the part of the upper end of the deformation member 2 extending out of the side support member 16 is wrapped by the PEEK material to improve the mechanical stability of the overall structure of the fusion device.

[0036] In an alternative embodiment of the present invention, preferably, the sides of the upper cover plate 13 and the lower cover plate 14 for contacting the vertebral end plates are provided as porous surfaces; specifically, the upper cover plate 13 and the lower cover plate 14 cover 96%-98% of the contact area between the fusion device and the end plates. The surface is subjected to micro-arc oxidation treatment to form a porous titanium layer with a pore diameter of 50-200 μm and a porosity of ≥65% to enhance the bone ingrowth ability by utilizing the excellent biocompatibility of titanium alloy.

[0037] In an alternative solution of this embodiment, more preferably, the bonding interfaces between the intermediate support 15 and the upper cover plate 13, the lower cover plate 14 and the side support members 16 are provided with strengthening layers. Specifically, by forming a titanium-PEEK transition layer, i.e., the strengthening layer, at the bonding interface, the interfacial shear strength is increased, thereby enhancing the overall stability. Specifically, through the composite 3D printing technology of selective laser melting (SLM) and fused deposition modeling (FDM), the titanium alloy and PEEK are fused with a gradient structure at the interface. A porous titanium transition layer with a gradually changing porosity is generated on the surface of the titanium alloy matrix, and then the PEEK matrix is printed layer by layer to form a reinforced interface with the synergism of mechanical interlocking and chemical bonding, enhancing the interfacial shear strength. This gradient structure makes the vertical stiffness of the fusion device show a non-linear gradient change, and at the same time, the stress concentration coefficient at the titanium-PEEK interface is significantly reduced, suppressing the risks of fretting wear and delamination failure.

[0038] More preferably, the upper cover plate 13, the lower cover plate 14 and the side support members 16 made of titanium alloy can be integrally formed by 3D printing, and the intermediate support 15 and the intermediate layer 17 made of the PEEK matrix are printed layer by layer with a layer thickness of 0.1 mm and a filling rate of 80%-85% to reduce the overall stiffness of the fusion device to 10-20 GPa close to that of cortical bone to reduce postoperative stress shielding. Among them, the thicknesses of the upper cover plate 13 and the lower cover plate 14 are 0.3±0.05 mm to reduce the risk of coating peeling during implantation.

[0039] In an alternative solution of this embodiment, more preferably, the matrix 1 is provided with a bone graft window 18, an observation window 19 and a surgical forceps operation opening 20. Specifically, the bone graft window 18 vertically penetrates the matrix 1, that is, the matrix 1 includes the upper cover plate 13, the lower cover plate 14, the intermediate support 15 and the intermediate layer 17 which are hollowly arranged to be able to enclose the bone graft window 18, and the bone graft window 18 provides a space for bone growth. The observation window 19 is arranged on the sides of the two side support members 16 and the intermediate support 15 to facilitate medical staff to observe the internal situation. The surgical forceps operation opening 20 is arranged on the rear side of the side support members 16 and the intermediate support 15 to be adapted to the existing minimally invasive endoscopic surgical implantation forceps on the market.

[0040] In an alternative solution of this embodiment, more preferably, the edges of the matrix 1 and each deformation component 2 are set as rounded corners to avoid possible stress concentration. Specifically, the upper cover plate 13, the lower cover plate 14 and the surface of the intermediate support 15 are provided with rounded corners with a radius of 0.5 mm to eliminate stress concentration at the interface between the fusion device and the end plate. Rounded corners with a radius of 0.05 mm are provided at the junction of titanium alloy-PEEK inside the fusion device and the structural edges of the deformation component 2, which can reduce the risk of local stress concentration and crack initiation under cyclic loading.

[0041] In an alternative embodiment of the present example, preferably, marking points for intraoperative imaging and positioning are provided on the edge of the matrix 1. Specifically, the upper cover plate 13 and the lower cover plate 14 are provided with fluorescent marking points made of europium-doped hydroxyapatite, which can be imaged and positioned under intraoperative X-ray fluoroscopy.

[0042] In an alternative embodiment of the present example, preferably, as Figure 3 shown, each deformation component 2 is arranged as a scissor-type telescopic component 21, and the side support member 16 has a sandwich layer 161, and the scissor-type telescopic component 21 is arranged in the sandwich layer 161 of the corresponding side support member 16. The scissor-type telescopic component 21 can deform with the change of the height of the vertebral interspace to provide non-linear support in the vertical direction. The height of the sandwich layer 161 is 7.7 ± 0.1 mm, and the wall thickness of the sandwich layer 161 is 0.1 mm, which improves the overall compressive strength and provides a safe and stable working environment for the scissor-type telescopic component 21 in a complex in-vivo environment, while ensuring that the minimum height of the fusion device can meet the requirements of the vertebral interspace.

[0043] Further preferably, the scissor-type telescopic component 21 is composed of a plurality of X-shaped cross-hinged units hinged in sequence. The rotation angle range of a single hinge point is ±15°, which can generate a non-linear stiffness response with the change of the height of the vertebral interspace, so that the fusion device provides a progressive support force of 10 - 80 N / mm in the vertical direction. Utilizing the characteristic that the scissor-type telescopic component 21 generates a reaction force when deforming, it can adapt to the physiological conditions of the patient to obtain an appropriate height change after fusion, preventing adjacent joint degeneration caused by possible rigid fixation. Wear-resistant bushings are provided at each hinge of the scissor-type telescopic component 21. Among them, the wear-resistant bushings are made of silicon nitride ceramic bushings, with a friction coefficient ≤ 0.02 and a wear-resistant cycle number ≥ 1×10 7 times, ensuring the service life. The X-shaped cross-hinged unit is composed of two crossed cantilevers hinged together, and the hinge is realized through hinge screws at the hinge.

[0044] Furthermore, the scissor-type telescopic component 21 can adjust parameters such as the span of a single hinged unit, the thickness of the cantilever, and the diameter of the hinge hole according to the physiological state of the patient, so as to be able to customize the vertical stiffness of each part of the fusion device, thereby improving the stability of the postoperative lumbar spine structure and the bone healing effect.

[0045] Among them, the usage state model of the spinal fusion device provided in this embodiment is as Figure 4 shown. The spinal fusion device is placed in the vertebral interspace of the L4 cortical bone 3 model of the vertebra. The vertebrae are connected and fixed by titanium rods 6 and pedicle screws 7, and an annulus fibrosus 5 is provided on the vertebra. A surgical endoscope channel 4 is provided on the vertebra, which is convenient for intraoperative endoscopic operation.

[0046] Embodiment Two

[0047] This embodiment provides a spinal fusion device, which is different from the spinal fusion device provided in the first embodiment: Please refer to Figure 5 , each deformation component 2 is set as an elastic member 22. The side support member 16 includes a support wall 162 and a plurality of sleeves 163. The plurality of sleeves 163 are arranged corresponding to the plurality of deformation components 2. Each sleeve 163 has a side opening and is connected to the support wall 162 to enclose a receiving cavity capable of receiving the corresponding deformation component 2; the elastic member 22 can deform as the height of the intervertebral space changes to provide dynamic support.

[0048] The working principle of the spinal fusion device provided in this embodiment is as follows:

[0049] The base body 1 is placed in the intervertebral space for support and fusion. Since a plurality of deformation components 2 are arranged side by side on the opposite first side 11 and second side 12 of the base body 1, each deformation component 2 can deform vertically as the height of the intervertebral space changes, and the plurality of deformation components 2 are distributed at multiple positions. By setting the deformation component 2 as an elastic member 22 with dynamic stiffness response, the elastic member 22 can generate a dynamic stiffness response as the height of the intervertebral space changes, simulating the dynamic response of the intervertebral disc in different physiological states (flexion, rotation, and lateral bending). It can provide appropriate height changes when the height of the intervertebral space changes, so as to realize the height self-adaptation of different parts of the fusion device, reduce the risk of adjacent joint degeneration, and improve the stability of the postoperative lumbar spine structure and the bone healing effect; and according to the biomechanical environment of the postoperative lumbar spine structure, by adjusting the parameters of the corresponding deformation component 2, the support performance of the corresponding part can be adjusted personalized, further reducing the risk of adjacent joint degeneration and improving the stability of the postoperative lumbar spine structure and the bone healing effect.

[0050] Further, the elastic member 22 is set as a spring that can deform in multiple axes, which is wound by using superelastic nickel-titanium alloy (NiTiNOL) wire. It realizes a progressive non-linear stiffness response and the ability of multi-axial deformation. When the elastic member 22 bears a vertical cyclic load of 10N - 800N (frequency 2Hz) in a simulated body fluid environment, the fatigue life ≥ 1×10 7 times, and the stiffness attenuation rate ≤ 5%, ensuring a sufficient service life;

[0051] Further preferably, the number and position distribution of the springs can be adjusted personalized according to the physiological state of different patients, and parameters such as the wire diameter, spring diameter, and effective number of turns of different springs can be adjusted, so as to be able to simulate the non-linear and anisotropic mechanical responses of the human intervertebral disc personalized, and adjust the vertical stiffness, lateral bending stiffness, and torsional stiffness of each part of the spinal fusion device. Prevent adjacent joint degeneration caused by possible rigid fixation; thus improving the stability of the postoperative lumbar spine structure and the bone healing effect.

[0052] Further preferably, the height of the titanium alloy sleeve 163 is equal to that of the titanium alloy support wall 162, providing a safe and stable working environment for the elastic member 22 by enclosing a receiving cavity in a complex in-vivo environment.

[0053] In addition, the other structures of the spinal fusion device provided in this embodiment are the same as those of the spinal fusion device provided in Embodiment 1, and will not be elaborated here.

[0054] In the present invention, specific examples are used to elaborate on the principles and implementation manners of the present invention. The descriptions of the above embodiments are only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation on the present invention.

Claims

1. A spinal fusion device, characterized in that: It includes a base body (1) which is used to be supported in the intervertebral space. The base body (1) includes opposite first side (11) and second side (12). A plurality of deformation components (2) arranged side by side in the horizontal direction are provided on both the first side (11) and the second side (12). Each of the deformation components (2) is vertically supported on the upper side and the lower side of the base body (1), and each of the deformation components (2) can deform with the change of the height of the intervertebral space so as to be capable of providing support.

2. The spinal fusion device according to claim 1, characterized in that: The base body (1) includes an upper cover plate (13), a lower cover plate (14), an intermediate support (15) and two side support members (16) respectively arranged on the first side (11) and the second side (12). The intermediate support (15) is arranged between the upper cover plate (13) and the lower cover plate (14), and the two side support members (16) are respectively arranged on the opposite sides of the intermediate support (15); each of the deformation components (2) is arranged inside the corresponding side support member (16), and both ends of each of the deformation components (2) are respectively connected to the upper cover plate (13) and the lower cover plate (14).

3. The spinal fusion device according to claim 2, characterized in that: The upper cover plate (13), the lower cover plate (14) and the side support members (16) are all made of titanium alloy material, and the intermediate support (15) is made of PEEK material.

4. The spinal fusion device according to claim 3, wherein: An intermediate layer (17) is arranged between the edge of the upper cover plate (13) and the upper ends between the two side support members (16). Each of the deformation components (2) penetrates through the intermediate layer (17) and is connected to the upper cover plate (13). The intermediate layer (17) is made of PEEK material.

5. The spinal fusion device according to claim 2, characterized in that: The sides of the upper cover plate (13) and the lower cover plate (14) for contacting the vertebral end plates are set as porous surfaces.

6. The spinal fusion device according to claim 2, wherein: Reinforcing layers are provided at the bonding interfaces of the intermediate support (15) with the upper cover plate (13), the lower cover plate (14) and the side support members (16).

7. The spinal fusion device according to claim 2, wherein: A bone graft window (18), an observation window (19) and an operating opening (20) for surgical forceps are provided on the base body (1).

8. The spinal fusion device according to claim 2, characterized in that: The edges of the base body (1) and each of the deformation components (2) are set as rounded corners; and marking points for imaging positioning are provided on the edge of the base body (1).

9. The spinal fusion device according to any one of claims 2-8, characterized in that: Each of the deformation components (2) is set as a scissor-type telescopic component (21). The side support member (16) has an interlayer (161), and the scissor-type telescopic component (21) is arranged in the interlayer (161) of the corresponding side support member (16); wear-resistant bushings are provided at each hinge of the scissor-type telescopic component (21); the scissor-type telescopic component (21) can deform with the change of the height of the intervertebral space so as to provide non-linear support in the vertical direction.

10. The spinal fusion device according to any one of claims 2-8, characterized in that: Each of the deformation components (2) is provided as an elastic member (22). The side support member (16) includes a support wall (162) and a plurality of sleeves (163). The plurality of sleeves (163) are correspondingly arranged with the plurality of deformation components (2). Each of the sleeves (163) has a side opening and is connected to the support wall (162) to enclose a receiving cavity capable of receiving the corresponding deformation component (2). The elastic member (22) can deform as the height of the vertebral space changes to provide dynamic support.

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