Expandable cage

Abstract

The application provides a distractible fusion cage for implanting into a vertebra from a vertebral foramen, which comprises: a front support part gradually decreasing from front to back along an X direction; a rear support part having a first state and a second state, when the rear support part is switched from the first state to the second state, two branches are distracted by the front support part; a support band ring, the front end of the support band ring is limited by the front support part, and the rear end passes through the rear support part; during the conversion of the rear support part from the first state to the second state, the front support part and the rear support part relatively move close to each other, so that the rear end of the support band ring protrudes backward relative to the rear support part, and the vertebral foramen is shielded. The support band ring of the distractible fusion cage of the application protrudes backward to shield the vertebral foramen, without the need of additional occlusion instruments, so that the loss of bone particles and bone mud from the open annular fibrosus incision into the fusion cage can be blocked, the bone graft amount of the intervertebral space is ensured, and the success rate of bone fusion is improved.

Description

Technical Field

[0001] This invention relates to the field of medical devices, and more particularly to an expandable fusion device. Background Technology

[0002] Minimally invasive lumbar interbody fusion surgery involves the implantation of a retractable fusion device through the vertebral orifice. During the procedure, the annulus fibrosus needs to be incised to create the implantation incision. Postoperatively, this incision is difficult to close spontaneously and cannot be routinely sutured, leaving the vertebral orifice in a persistently open state – a common clinical challenge that urgently needs to be addressed. Current retractable fusion devices only focus on intervertebral disc height support and internal bone graft space expansion, without designing a corresponding shielding structure for the open vertebral orifice, thus failing to seal the annulus fibrosus incision at the implant level itself.

[0003] When the open intervertebral foramen lacks containment, the autologous bone and bone replacement particles filling the fusion cage are loose and unrestrained, making them highly susceptible to leakage through the foramen. Significant loss of bone graft material directly reduces the effective osteogenic raw material within the intervertebral space, drastically decreasing bone ingrowth efficiency and increasing the probability of postoperative complications such as fusion failure, pseudoarthrosis, and vertebral instability. Sealing the intervertebral foramen requires additional sealing instruments, making the surgical procedure cumbersome.

[0004] In view of this, it is necessary to improve the existing fusion device to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide an expandable fusion device to solve the problem of easy loss of internal filler after implantation of existing fusion devices.

[0006] To achieve the above objectives, the present invention provides a retractable fusion device for implantation into the vertebral bone through the vertebral foramen, the retractable fusion device comprising:

[0007] A front support portion, wherein the front support portion gradually decreases in size from front to back along the X direction; The rear support portion has two interconnected branches. The rear support portion is elastic and has a first state and a second state. When the rear support portion switches from the first state to the second state, the two branches are spread apart by the front support portion. When the rear support portion is in the first state, the rear support portion is located behind the front support portion along the X direction, and the front ends of the two branches are arranged close to each other. When the rear support portion is in the second state, the two branches of the rear support portion cover both sides of the front support portion along the Y direction. The support belt loop is provided, with the front support portion limiting the front end of the support belt loop and the rear end passing through the rear support portion. During the transition of the rear support portion from the first state to the second state, the front support portion and the rear support portion move relatively closer to each other, causing the rear end of the support belt loop to protrude rearward relative to the rear support portion to cover the vertebral incision.

[0008] As a further improvement of the present invention, the support belt ring is made of an elastic material.

[0009] As a further improvement of the present invention, the support belt ring is composited with a piezoelectric material.

[0010] As a further improvement of the present invention, the front support portion is provided with a receiving groove extending in the X direction, and the front end of the support belt ring has a first position located at the front end of the receiving groove and a second position located at the rear end of the receiving groove. When the rear support portion is in the second state, the front end of the support belt ring is located in the second position.

[0011] As a further improvement of the present invention, the expandable fusion device further includes a guide shaft disposed at the front end of the support belt ring. The front support portion is provided with two guide grooves for the guide shaft to move in the X direction. The guide shaft extends in the Z direction, and the guide grooves on both sides are located on both sides of the receiving groove in the Z direction. The front end of the support belt ring covers the guide shaft. When the support belt ring moves from the first position to the second position, it drives the guide shaft to move along the guide groove.

[0012] As a further improvement of the present invention, the front support portion is provided with a limiting groove extending in the Y direction and a limiting rod disposed in the limiting groove, and the rear support portion is provided with limiting portions spaced apart in the Z direction. When the rear support portion is in the second state, the limiting portions are located on both sides of the limiting rod to restrict the relative movement of the front support portion and the rear support portion in the Z direction.

[0013] As a further improvement of the present invention, the limiting groove is connected through the receiving groove, one end of the limiting rod protrudes into the receiving groove, and the limiting rod is provided with a guide slope. When the support belt ring moves from the first position to the second position, the guide shaft abuts against the guide slope to push the limiting rod partially out of the limiting groove along the Y direction.

[0014] As a further improvement of the present invention, the limiting rods are configured in multiple groups, each group having two limiting rods, the multiple groups of limiting rods being spaced apart along the X direction, and the two limiting rods of each group being respectively located at both ends of the support belt ring along the Y direction.

[0015] As a further improvement of the present invention, the rear support portion is provided with a through hole for the support belt ring to pass through. When the rear support portion is in the second state, the rear support portion clamps the support belt ring at the through hole position.

[0016] As a further improvement of the present invention, both the front support portion and the rear support portion are made of shape memory PEEK substrate.

[0017] As a further improvement of the present invention, both the front support portion and the rear support portion are provided with anti-slip stripes on their surfaces.

[0018] The beneficial effects of this invention are: the support ring of the expandable fusion device protrudes backward to cover the vertebral incision, eliminating the need for additional sealing instruments, preventing bone particles and bone deposits inside the fusion device from leaking out from the open annulus fibrosus incision, ensuring the amount of bone graft in the intervertebral space, improving the success rate of bony fusion, and reducing the risk of pseudoarthrosis and vertebral instability. Attached Figure Description

[0019] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a three-dimensional structural diagram of the expandable fusion device of the present invention; Figure 2 This is a top view of the expandable fusion device of the present invention when implanted into the vertebrae; Figure 3 This is a top view schematic diagram of the expandable fusion device of the present invention after implantation into the vertebrae; Figure 4 This is a side view of the expandable fusion device of the present invention when the rear support is in the first state; Figure 5 This is a side view of the expandable fusion device of the present invention when the rear support is in the second state; Figure 6 This is a side view of the front support portion of the expandable fusion device of the present invention; Figure 7 yes Figure 6 Schematic diagram of the cross-sectional structure along the AA direction; Figure 8 This is a top view of the front support portion of the expandable fusion device of the present invention; Figure 9 yes Figure 8 A schematic diagram of the cross-sectional structure along the BB direction.

[0020] Reference numerals: 100, expandable fusion device; 1, front support; 11, receiving groove; 12, guide groove; 13, limiting groove; 14, limiting rod; 141, guide slope; 2, rear support; 21, branch; 22, through hole; 23, limiting part; 3, support belt ring; 4, guide shaft; 5, anti-slip stripe; 200, vertebra; 201, vertebral orifice. Detailed Implementation

[0021] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for 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 the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0023] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Furthermore, the technical features involved in the different embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0024] like Figures 1 to 9 As shown, the present invention provides a retractable fusion device 100 for implantation into a vertebra 200 through a vertebral orifice 201. The retractable fusion device 100 includes: Front support portion 1, wherein the front support portion 1 gradually decreases in size from front to back along the X direction; The rear support portion 2 has two interconnected branches 21. The rear support portion 2 is elastic and has a first state and a second state. When the rear support portion 2 switches from the first state to the second state, the two branches 21 are spread apart by the front support portion 1. When the rear support portion 2 is in the first state, the rear support portion 2 is located behind the front support portion 1 along the X direction, and the front ends of the two branches 21 are close to each other. When the rear support portion 2 is in the second state, the two branches 21 of the rear support portion 2 cover both sides of the front support portion 1 along the Y direction. The support belt loop 3 is provided, with the front support portion 1 limiting its front end and the rear end passing through the rear support portion 2. During the transition of the rear support portion 2 from the first state to the second state, the front support portion 1 and the rear support portion 2 move relatively closer together, causing the rear end of the support belt loop 3 to protrude rearward relative to the rear support portion 2 to cover the vertebral orifice 201. Furthermore, the rear end of the support belt loop 3 can slide through the rear support portion 2.

[0025] In this embodiment, the front support part 1 limits the support belt ring 3 when the rear support part 2 switches states.

[0026] In this embodiment, the rear ends of the two branches 21 are connected, while the front ends are free and can move relative to each other.

[0027] In this embodiment, the X direction is the implantation direction, the Z direction is the height direction of the expandable fusion device 100, and the Y direction is the width direction. The height direction here can also be understood as the height direction of the vertebra 200.

[0028] The posterior support 2 is elastic and can be stretched to accommodate small daily spinal movements, buffering the load between vertebrae, further optimizing the mechanical environment of the bone-implant interface, and promoting bone ingrowth.

[0029] Before and during implantation, the posterior support portion 2 of the expandable fusion device 100 is in its first state. In this state, the posterior support portion 2 is positioned behind the anterior support portion 1 along the X-direction. The front ends of the two branches 21 of the posterior support portion 2 are close together, and the overall outer diameter is small, allowing it to be smoothly inserted into the intervertebral space through the vertebral orifice 201. The front end of the support band ring 3 is fixed to the anterior support portion 1, and the rear end passes through the posterior support portion 2, without interfering with the implantation operation. Furthermore, when the posterior support portion 2 is in its first state, the branches 21 are closed and joined together, resulting in a compact overall profile that fits the narrow vertebral orifice 201 channel of the minimally invasive procedure, reducing traction damage to the annulus fibrosus and surrounding soft tissues during surgery.

[0030] During the transition of the rear support 2 from the first state to the second state, the front support 1 and the rear support 2 are driven to move closer to each other along the X direction. The tapered front support 1 presses forward against the two branches 21 of the elastic rear support 2, and the two branches are pushed apart to the Y direction by the conical thrust. As the two continue to move closer, the rear end of the support belt ring 3 inserted in the rear support 2 is pushed backward and protrudes backward relative to the rear support 2.

[0031] When the rear support 2 is in the second state, the two branches 21 are fully opened and cover the Y-direction sides of the front support 1, forming a lateral wrapping support structure; the rearward protruding segment of the support band ring 3 covers and shields the vertebral orifice 201 formed by the surgery, completing the self-sealing.

[0032] In this embodiment, the position of the front support part 1 can be limited by pulling the support belt ring 3, and the transition from the first state to the second state can be achieved by pushing the rear support part 2 from the rear.

[0033] The opening action, in conjunction with the support ring 3, causes it to protrude posteriorly to cover the vertebral orifice 201, eliminating the need for additional sealing instruments. This prevents bone particles and bone deposits within the fusion cage from leaking out through the open annulus fibrosus incision, ensuring sufficient bone graft volume in the intervertebral space, improving the success rate of bony fusion, and reducing the risk of pseudoarthrosis and vertebral instability. Furthermore, even if the support ring 3 does not completely cover the vertebral orifice 201, leaving a gap, the adhesiveness of the filler will prevent it from flowing out. Relying solely on the coordination of the anterior support part 1, the elastic posterior support part 2, and the support ring 3, a single opening action simultaneously completes both lateral support shaping and automatic covering of the vertebral orifice 201, eliminating the need for additional sealing steps, shortening surgical time, and reducing operational difficulty.

[0034] Therefore, in this embodiment, the support belt ring 3 can serve to assist the combination of the front support part 1 and the rear support part 2, and can also serve to cover the vertebral orifice 201.

[0035] The posterior support 2, with its two branches 21, expands and covers both sides of the anterior support 1 along the Y direction, significantly increasing the effective contact area between the fusion device and the endplates of the upper and lower vertebral bodies, dispersing interface contact stress, avoiding local stress concentration, and reducing complications such as fusion device subsidence and postoperative loosening.

[0036] The support ring 3 is made of an elastic material. Made of an elastic material, the support ring 3 possesses bendable and resilient properties, allowing it to flexibly deform and adapt to displacement during the relative movement and expansion of the front and rear support parts 2, preventing breakage or jamming. Simultaneously, the elastic material can conform to the contour of the vertebral orifice 201 for a tight seal, further improving the bone graft's anti-leakage effect. It can also undergo small elastic deformation with spinal movement, buffering intervertebral loads. The support ring 3 can also be made of silicone material.

[0037] In addition, the support band ring 3 is elastic and can be used to fill bone paste from the vertebral orifice 201 during the operation, as long as the instrument pushes open the support band ring 3.

[0038] The support ring 3 is incorporating a piezoelectric material. When the spine moves or the fusion device 100 is deformed by force, the piezoelectric material can generate a microcurrent electrical stimulation, which continuously acts on the surrounding bone tissue, effectively activating osteoblast activity, accelerating bone ingrowth, improving the efficiency of vertebral body fusion, and reducing the risk of postoperative pseudoarthrosis.

[0039] like Figures 6 to 9As shown, the front support 1 has a receiving groove 11 extending in the X direction. The front end of the support ring 3 has a first position at the front end of the receiving groove 11 and a second position at the rear end of the receiving groove 11. When the rear support 2 is in the second state, the front end of the support ring 3 is in the second position. The front support 1 has a receiving groove 11 extending in the X direction. The front end of the support ring 3 can switch between the first and second positions within the receiving groove 11. When the support ring 3 is opened to the second state, the front end of the support ring 3 slides to the rear end of the receiving groove 11, which can stably limit the relative displacement of the support ring 3 and control the length of the rear end of the support ring 3 that protrudes backward, ensuring a stable sealing effect of the vertebral opening 201. At the same time, the receiving groove 11 provides a regular sliding guide for the support ring 3, avoiding ring offset, twisting and jamming, ensuring smooth linkage of the opening action, and improving the reliability of the structural movement.

[0040] The expandable fusion device 100 also includes a guide shaft 4 disposed at the front end of the support ring 3. The front support portion 1 has two guide grooves 12 for the guide shaft 4 to move along the X direction. The guide shaft 4 extends along the Z direction, and the guide grooves 12 on both sides are located on both sides of the receiving groove 11 along the Z direction. The front end of the support ring 3 covers the guide shaft 4. When the support ring 3 moves from the first position to the second position, it drives the guide shaft 4 to move along the guide grooves 12. The addition of the Z-direction extending guide shaft 4, in conjunction with the symmetrically arranged guide grooves 12, allows the support ring 3 to move, driving the guide shaft 4 to slide linearly along the guide grooves 12. This provides bidirectional limiting guidance for the support ring 3, preventing lateral displacement, twisting, or dislodgement. The guide grooves 12 are arranged on both sides of the receiving groove 11, with a regular movement trajectory, ensuring smooth and stable forward and backward movement of the support ring 3. This precisely controls the stroke of the rear end of the support ring 3 protruding to block the vertebral orifice 201, ensuring a stable bone graft sealing effect and improving the movement accuracy and assembly reliability of the overall expandable linkage structure.

[0041] The front support portion 1 is provided with a limiting groove 13 extending along the Y direction and a limiting rod 14 disposed in the limiting groove 13. The limiting rod 14 can slide in the limiting groove 13. The rear support portion 2 is provided with limiting portions 23 spaced apart along the Z direction. When the rear support portion 2 is in the second state, the limiting portions 23 are located on both sides of the limiting rod 14 to restrict the relative movement of the front support portion 1 and the rear support portion 2 along the Z direction.

[0042] By cooperating with the limiting rod 14 in the limiting groove 13 and the limiting parts 23 on both sides of the rear support part 2, when the fusion device 100 is opened to the second state, the limiting part 23 is blocked on both sides of the limiting rod 14, which can limit the relative displacement of the front and rear support parts 2 along the Z direction; avoid the left and right misalignment and uneven force of the rear support branches 21 on both sides, stabilize the lateral wrapping support shape, maintain the central sealing position of the support belt ring 3, ensure the continuous and reliable shielding effect of the vertebral orifice 201, balance the force on both sides of the vertebral body, reduce the risk of sinking and loosening caused by local stress concentration, and improve the stability of the overall structure after it is opened.

[0043] The limiting groove 13 passes through and communicates with the receiving groove 11. One end of the limiting rod 14 protrudes into the receiving groove 11. The limiting rod 14 is provided with a guide slope 141. When the support belt ring 3 moves from the first position to the second position, the guide shaft 4 abuts against the guide slope 141 to push the limiting rod 14 partially out of the limiting groove 13 along the Y direction.

[0044] The limiting groove 13 is interconnected with the receiving groove 11, and the end of the limiting rod 14 has a guide slope 141. When implanted and retracted, the limiting rod 14 is completely retracted into the limiting groove 13 without any protruding structure. The overall shape is neat and compact, and it will not scratch the annulus fibrosus or hinder the insertion of instruments, thus smoothly completing the minimally invasive implantation. During the opening process, the guide shaft 4 slides along the support belt ring 3 to press against the guide slope 141, driving the limiting rod 14 to extend along the Y direction. It cooperates with the limiting part 23 of the rear support part 2 to achieve Z-direction limiting. The limiting and locking are automatically completed only after the implantation is formed, taking into account both the convenience of implantation and the structural stability after opening.

[0045] The limiting rods 14 are configured in multiple sets, each set having two limiting rods 14. These sets of limiting rods 14 are spaced apart along the X-direction, with the two limiting rods 14 in each set positioned at both ends of the support ring 3 along the Y-direction. The arrangement of multiple sets of paired limiting rods 14 at intervals along the X-direction, with each set of two limiting rods 14 positioned at both ends of the support ring 3 along the Y-direction, allows for simultaneous double-sided limiting constraints on the front and rear support parts 2 from front to back after the fusion assembly is expanded and formed. This multi-point limiting can evenly distribute lateral offset loads, preventing single-point limiting from failing due to overload, and comprehensively restricting the Y-direction misalignment of the front and rear support parts 2. It stabilizes the rear support branch 21's covering shape and the centrally sealed position of the support ring 3, further improving the overall rigidity and long-term stability of the structure after expansion.

[0046] The rear support portion 2 has a through hole 22 for the support band 3 to pass through. When the rear support portion 2 is in the second state, it clamps the support band 3 at the through hole 22. The through hole 22 in the rear support portion 2 allows the support band 3 to pass through. When opened to the second state, the through hole 22 clamps and fixes the support band 3. This serves two purposes: firstly, it constrains the middle section of the support band 3, preventing vertical or horizontal displacement and ensuring the rear end of the support band 3 stably protrudes backward to cover the vertebral orifice 201, continuously preventing bone graft leakage; secondly, the clamping structure of the through hole 22 allows the support band 3 to move synchronously with the relative sliding of the front and rear supports, enabling the opening action and the sealing action of the vertebral orifice 201 to be completed simultaneously, improving the precision of the linkage between components. Simultaneously, the clamping action shares the tensile stress of the support band 3, reducing the risk of long-term stress fracture and extending the lifespan of the implant.

[0047] Both the anterior support portion 1 and the posterior support portion 2 are made of shape memory PEEK (polyetheretherketone) substrate. This material combines high strength, high rigidity, and biocompatibility, providing stable support for the upper and lower vertebral bodies, resisting intervertebral loads, and reducing the risk of subsidence of the expandable fusion device 100. It also possesses shape memory rebound characteristics; in the implanted and retracted state, it maintains a compact shape to fit the minimally invasive channel, and after expansion, it automatically rebounds and reshapes, maintaining a durable lateral coverage and support form, adapting to the physiological micro-movements of the spine, evenly dispersing endplate contact stress, and further optimizing the mechanical environment for bone fusion.

[0048] Both the front support portion 1 and the rear support portion 2 are provided with anti-slip stripes 5. In this embodiment, the anti-slip stripes 5 extend along the Y direction. The anti-slip stripes 5 increase the coefficient of friction between the front support portion 1, the rear support portion 2 and the contacting object, improve the anti-slip performance of the contact surface, and prevent slippage.

[0049] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0050] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A retractable fusion device for implantation into the vertebral bone through the vertebral foramen, characterized in that: The expandable fusion device includes: A front support portion, wherein the front support portion gradually decreases in size from front to back along the X direction; The rear support portion has two interconnected branches. The rear support portion is elastic and has a first state and a second state. When the rear support portion switches from the first state to the second state, the two branches are spread apart by the front support portion. When the rear support portion is in the first state, the rear support portion is located behind the front support portion along the X direction, and the front ends of the two branches are arranged close to each other. When the rear support portion is in the second state, the two branches of the rear support portion cover both sides of the front support portion along the Y direction. The support belt loop has a front support portion that limits the front end of the support belt loop, and a rear end that passes through the rear support portion. During the transition of the rear support portion from the first state to the second state, the front support portion and the rear support portion move relatively closer to each other, causing the rear end of the support belt loop to protrude rearward relative to the rear support portion to cover the vertebral opening. The support belt loop is made of an elastic material. The front support portion is provided with a receiving groove extending in the X direction. The front end of the support belt ring has a first position located at the front end of the receiving groove and a second position located at the rear end of the receiving groove. When the rear support portion is in the second state, the front end of the support belt ring is located in the second position. The rear support portion has a through hole for the support belt ring to pass through. When the rear support portion is in the second state, the rear support portion clamps the support belt ring at the through hole position. The expandable fusion device also includes a guide shaft disposed at the front end of the support belt ring. The front support portion is provided with two guide grooves for the guide shaft to move along the X direction. The guide shaft extends along the Z direction, and the guide grooves on both sides are located on both sides of the receiving groove along the Z direction. The front end of the support belt ring covers the guide shaft. When the support belt ring moves from the first position to the second position, it drives the guide shaft along the guide groove.

2. The expandable fusion device according to claim 1, characterized in that: The support belt ring is incorporating a piezoelectric material.

3. The expandable fusion device according to claim 1, characterized in that: The front support portion is provided with a limiting groove extending in the Y direction and a limiting rod disposed in the limiting groove. The rear support portion is provided with limiting portions spaced apart in the Z direction. When the rear support portion is in the second state, the limiting portions are located on both sides of the limiting rod to restrict the relative movement of the front support portion and the rear support portion in the Z direction.

4. The expandable fusion device according to claim 3, characterized in that: The limiting groove extends through and connects to the receiving groove. One end of the limiting rod protrudes into the receiving groove. The limiting rod is provided with a guide slope. When the support belt ring moves from the first position to the second position, the guide shaft abuts against the guide slope to push the limiting rod partially out of the limiting groove along the Y direction.

5. The expandable fusion device according to claim 4, characterized in that: The limiting rods are configured in multiple groups, each group having two limiting rods. The multiple groups of limiting rods are spaced apart along the X direction, and the two limiting rods of each group are respectively located at both ends of the support belt ring along the Y direction.

6. The expandable fusion device according to claim 1, characterized in that: Both the front support and the rear support are made of shape memory PEEK substrate.

7. The expandable fusion device according to claim 1, characterized in that: The surfaces of both the front support and the rear support are provided with anti-slip stripes.

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