Lateral variable-angle fusion cage

Abstract

The utility model discloses a lateral variable-angle fusion cage which structurally utilizes a multi-stage guide structure to movably connect a distraction body with two cover plates, guide blocks on two sides of the distraction body are asymmetrically arranged, the guide blocks on different sides have different inclination differences, and the purpose of variable-angle distraction adjustment can be achieved. The operation of selecting specifications through frequent mold testing in the prior art is overcome, and the time of mold testing in an operation is saved; according to the technical scheme, by matching with the 3D printing technology, under the condition that screws and other fixing pieces are not used, accurate product assembling can be conducted through the matching relation between the components, the overall structure is simple and reasonable, the production efficiency can be improved, more stable and effective supporting is achieved, and meanwhile operation steps are greatly simplified.

Description

Technical Field

[0001] This application belongs to the field of spinal implants, specifically relating to a lateral approach variable-angle fusion device. Background Technology

[0002] Surgical treatment of degenerative spinal diseases traditionally involves open surgery, primarily the classic posterior lumbar interbody fusion (PLIF) and transforaminal lumbar interbody fusion (TLIF). However, open surgery inevitably damages one facet joint, potentially affecting the overall biomechanics and structural stability of the spine postoperatively. In addition, the extensive paraspinal muscle stripping, significant soft tissue damage, and prolonged nerve root traction during surgery can lead to long-term chronic low back and leg pain, reducing patients' quality of life.

[0003] In recent years, minimally invasive treatments have developed rapidly. Commonly used procedures such as percutaneous endoscopic transforaminal lumbar interbody fusion (Endo-TLIF) and unilateral dual-channel endoscopic interbody fusion (UBE) each have their own advantages. However, clinical studies have found that both of these surgical methods have drawbacks such as incomplete decompression and poor restoration of intervertebral disc height. The main reason is that the fusion cages used are mostly of fixed height. During the operation, trial molding tools are needed to repeatedly adjust and test to select a fusion cage of a suitable height. In many cases, it is impossible to select a sufficiently suitable fusion cage. An unsuitable fusion cage height will lead to insufficient contact between the fusion cage and the bone tissue, poor bone ingrowth, and gaps will affect the actual stress distribution, resulting in uneven stress distribution and problems such as fusion cage subsidence. Therefore, how to achieve sufficient contact between the fusion cage and the bone tissue is an urgent problem to be solved. Utility Model Content

[0004] The purpose of this invention is to provide a lateral approach variable angle fusion device that can be adjusted in a controllable angle after implantation, thereby achieving more stable and effective support and greatly simplifying the surgical procedure.

[0005] To achieve the above objectives, this application adopts the following technical solution.

[0006] The lateral variable-angle fusion device includes: a cover plate, a support body, a main frame, a guide structure, and a drive mechanism; wherein, the main frame is a frame without panels on the upper and lower end faces, and the two ends of the main frame along its length are the implantation end and the rear end, respectively, and a first through hole and a second through hole that cooperate with the drive mechanism are respectively provided on the rear end and the implantation end; the cover plate includes: an upper cover plate and a lower cover plate, which cover the upper and lower end faces of the main frame; the support body is located inside the main frame and is movably connected to the cover plate through the guide structure. The support body moves in the plane of the main frame through the drive device connected to it, and the guide structure moves with the support body, causing the upper and lower cover plates to unfold;

[0007] The guiding structure includes a guide block and a guide groove. The direction of the guide groove is the same as the inclination direction of the guide block, and the guide block and the guide groove cooperate with each other. The guide block is located at the edge of the supporting body, and the guide groove is located on the cover plate. The guide block on the supporting body is placed in the corresponding guide groove on the cover plate, thereby movably connecting the supporting body and the cover plate.

[0008] Furthermore, the guide block includes: a first guide block, a second guide block, and a third guide block. The first guide block and the second guide block are located on opposite sides of the length direction of the expander, and the third guide block is located on both sides of the cover plate near the implantation end and the rear end, so that the third guide block is located on different sides from the first guide block and the second guide block.

[0009] Furthermore, the tilt angles of the first guide block and the second guide block are different.

[0010] Furthermore, the driving mechanism includes a driving rod that passes through a first through hole on the main frame and is threadedly engaged with the expansion body. After implantation, by rotating the driving rod, the expansion body is driven to move within the inner frame using the threaded engagement.

[0011] Furthermore, it also includes: a limiting rod, which passes through the second through hole on the main frame and connects to the supporting body, and the direction of the limiting rod is the same as the movement direction of the supporting body.

[0012] Furthermore, the first through hole can be divided into a near-mouth section, a slot, and a far-mouth section. The near-mouth section connects to the inner side of the main frame. The diameter of the slot is larger than that of the near-mouth section. The diameter of the far-mouth section is the same as that of the slot and is threaded. Correspondingly, the drive rod is provided with an adjustment section and a limiting section. During assembly, the limiting section is screwed into the slot of the first through hole.

[0013] Furthermore, the drive rod is a hollow rod with a through channel at its axis position, which serves as a bone graft channel during use.

[0014] Furthermore, the cover plate is pre-set with several hollow areas, the edges of which are closed shapes. The hollow areas are equipped with porous structures, which are formed by 3D printing technology and are similar to the porous structure of human bone trabeculae.

[0015] This application has at least the following beneficial effects:

[0016] The multi-level guide structure is used to movably connect the expansion body to the two cover plates. The guide blocks on both sides of the expansion body are asymmetrically set, and the guide blocks on opposite sides have different inclination differences, which can achieve the purpose of variable angle expansion adjustment. This overcomes the operation of selecting specifications through frequent trial molding in the existing technology and saves the time of trial molding during the operation.

[0017] The multi-level guide structure connects the support body and the cover plate, and the drive mechanism connects the support body and the main frame. With the help of 3D printing technology, products can be precisely assembled by utilizing the fit between components without the use of screws or other fasteners. The overall structure is simple and reasonable, which helps to improve production efficiency.

[0018] By fully integrating with 3D printing technology, the cover plate that comes into contact with the affected area is equipped with a porous structure, which maintains limb strength while reducing weight and improving bone ingrowth.

[0019] The main frame and cover plate are assembled to ensure that there is space for bone grafting windows inside; a bone grafting channel is set on the drive rod, which can be used to fill the gap after the angle is adjusted, avoiding the risk of voids after expansion. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 An exploded view of this application is shown schematically;

[0022] Figure 2 This schematic diagram illustrates the structure of the application in its closed state.

[0023] Figure 3 This schematic diagram illustrates the structure of the present application in its unfolded state;

[0024] Figure 4 The schematic diagram illustrates the unfolding process of this application from a side view angle;

[0025] Figure 5 A schematic diagram illustrating the relationship between the main frame and the drive rod is provided.

[0026] Figure 6 The schematic diagram shows the structure of the expandable body from a side view.

[0027] Figure 7 The schematic diagram shows the structure of this application from a top view after the hollowed-out area has been removed;

[0028] Figure 8 This is a schematic diagram of the cross-sectional structure taken along line CC;

[0029] Figure 9 This is a schematic diagram of the cross-sectional structure cut along line DD.

[0030] Wherein: 11-upper cover plate, 12-lower cover plate, 13-hollowed-out area;

[0031] 20-Main frame, 21-First through hole, 21a-Proximal segment, 21b-Card slot, 21c-Distal segment, 22-Second through hole, 23-Clamping position, 24-Rear end, 25-Implantation end; 30-Stabilizer;

[0032] 41a - First guide block, 41b - Second guide block, 41c - Third guide block, 42 ​​- Guide groove;

[0033] 51-Drive rod, 51a-Adjustment section, 51b-Limiting section, 52-Limiting rod, 53-Bone grafting channel. Detailed Implementation

[0034] To provide a clearer understanding of the technical features, objectives, and effects of this utility model, the specific embodiments of this utility model are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that the orientations or positional relationships indicated by terms such as "front," "rear," "upper," "lower," "left," "right," "longitudinal," "horizontal," "vertical," "horizontal," "top," "bottom," "inner," "outer," "head," and "tail" are based on the orientations or positional relationships shown in the accompanying drawings, and are constructed and operated in a specific orientation. They are only for the convenience of describing this technical solution and do not indicate that the device or component referred to must have a specific orientation; therefore, they should not be construed as limitations on this utility model.

[0035] It should also be noted that, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "joining," "fixing," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components. When an component is referred to as being "on" or "below" another component, the component can be located "directly" or "indirectly" on the other component, or there may be one or more intermediary elements. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances. Example

[0036] In existing technologies, variable-angle expansion is mostly achieved through a rotating shaft or similar shaft connection structure, which increases the manufacturing difficulty. At the same time, the rotating shaft structure usually needs to be used with a stop structure for fixation. The size of such stop structures is fixed and cannot achieve stepless adjustment. However, medical devices used for implantation in the human body cannot ignore the differences in human physiological structure. Different physiological structures determine that the expansion angle during surgery is not exactly the same. Fixed-specification components cannot meet the requirements of everyone. Therefore, this application proposes a lateral variable-angle fusion device. By using a fusion device with adjustable height and angle, the problem of large implantation gap of existing intervertebral / body implants is solved, and the fusion device is made in close contact with the implantation site, which facilitates the subsequent ingrowth of bone tissue.

[0037] like Figure 1 As shown, its structure includes: a cover plate, a supporting body 30, a main frame 20, a multi-stage guide structure, and a drive mechanism. The upper and lower cover plates 12 and the main frame 20 are combined to form the main body of the product. The part enclosed by the cover plate and the main frame 20 is the bone grafting area, which can be used to fill with bone fragments and other fillers to promote bone ingrowth. The supporting body 30 is connected to the cover plate through the multi-stage guide structure and to the main frame 20 through the drive mechanism. The drive mechanism drives the supporting body 30 to move within the main frame 20, thereby causing the cover plate to unfold. Its effect is as follows: Figures 2-3 As shown, the multi-level guide structure can further achieve the effect of variable angle deployment through different slope designs.

[0038] like Figure 4 As shown, the main frame 20 is a frame body. The upper and lower ends of the main frame 20 do not have panels. The main frame 20 has different thicknesses on its two long sides, and correspondingly, both ends are inclined towards the shorter long side. Figures 1-3 As shown, the two short sides of the main frame 20 are the implantation end 25 and the rear end 24, respectively. The implantation end 25 of the main frame 20 is a smooth curved surface with a large arc, which facilitates smooth implantation into the predetermined position through the side approach minimally invasive channel formed during the operation. The rear end 24 is provided with a clamping position 23 for holding. The clamping position 23 is a concave bayonet that can cooperate with the end structure of the clamp in the prior art. In addition, the implantation end 25 and the rear end 24 are respectively provided with a first through hole 21 and a second through hole 22 that cooperate with the driving mechanism.

[0039] The cover plate has the same shape as or is slightly smaller than the main frame 20, and covers the end face of the main frame 20, such as... Figure 1 As shown, the cover plate is divided into an upper cover plate 11 and a lower cover plate 12, located on the upper and lower sides of the middle frame, and together with the main frame 20 and the supporting body 30, they form a whole. An opening is provided in the middle of the cover plate. After being combined with the main frame 20, the space enclosed by the two is the bone graft space, and the opening on the cover plate serves as the bone graft port for the bone graft space, which facilitates the filling and compaction of fillers such as bone fragments.

[0040] The cover plate has several pre-set hollow areas 13, which are located between the edge and the opening in the middle. The hollow areas inside are equipped with a porous structure. The porous structure is formed by 3D printing technology and is similar to the porous structure of human bone trabeculae. It is used to increase the contact area with bone, which is conducive to the inward growth of bone tissue; it can also effectively reduce the overall weight.

[0041] In a preferred embodiment, the distance between the edge of the hollow area 13 and the edge of the cover plate or the opening edge in the middle is 1~1.5mm; to ensure sufficient structural strength.

[0042] The supporting body 30 is located in the space enclosed by the cover plate and the main frame 20. Its area is smaller than that of the main frame 20. The supporting body 30 is connected to the upper and lower cover plates 12 through a multi-level guide structure, and is connected to the main frame 20 through a drive mechanism. Under the action of the drive mechanism, it moves within the main frame 20.

[0043] Specifically, the drive structure includes a drive rod 51 and a limiting rod 52. The limiting rod 52 passes through the second through hole 22 and is connected to the support body 30. The direction of the limiting rod 52 is the same as the direction of movement of the support body 30. When the support body 30 moves, it restricts its direction of movement, making the operation of the support body 30 more stable. The drive rod 51 passes through the first through hole 21 and is threadedly connected to the support body 30. After implantation, by rotating the drive rod 51, the support body 30 is driven to move in the inner frame.

[0044] Furthermore, such as Figure 5 As shown, the drive rod 51 is provided with two external threads: an adjusting section 51a and a limiting section 51b. The limiting section 51b is located near the end of the drive rod 51, and its outer diameter is larger than that of the adjusting section 51a. After the adjusting section 51a passes through the first through hole 21, it is threadedly connected to the supporting body 30 in the inner frame. The structure of the corresponding first through hole 21 is as follows: Figure 5 As shown, the first through hole 21 can be divided into three interconnected hollow sections: a near-mouth section 21a, a slot 21b, and a far-mouth section 21c. The near-mouth section 21a is closer to the inner side of the main frame 20. The diameter of the slot 21b is larger than that of the near-mouth section 21a, while the diameter of the far-mouth section 21c is the same as that of the slot 21b and is threaded. Of course, the length of the limiting section 51b is less than or equal to the length of the slot 21b.

[0045] During assembly, the adjusting section 51a of the drive rod 51 passes through the first through hole 21 and is threadedly connected to the support body 30. As the drive rod 51 rotates, the limiting section 51b passes through the distal section 21c and enters the slot 21b. As the drive rod 51 continues to rotate, the limiting section 51b disengages from the distal section 21c and enters the slot 21b. The drive rod 51 no longer undergoes axial movement, but only circumferential movement, which is equivalent to being "embedded" in the first through hole 21.

[0046] In use, simply continue rotating the drive rod 51 to move the expansion body 30 along the axis of the drive rod 51, thus unfolding the cover plate. This drive structure allows for stepless adjustment of the unfolding angle. Moreover, the drive rod 51 and the first through hole 21 have a unique embedded connection, not a simple threaded connection. If it were a threaded connection, a section of the drive rod 51 would always be exposed outside the main frame 20, which would undoubtedly be dangerous inside the body. In this application, the drive rod 51 is "embedded" in the first through hole 21, overcoming the above-mentioned technical problems. Furthermore, the "embedded" connection method improves the stability during use. In addition, the drive rod 51 does not protrude from the surface of the rear end 24, avoiding scratching other tissues after implantation.

[0047] Additionally, since the material filled into the bone graft space before product implantation cannot exceed the cover plate, otherwise it will affect the implantation minimally invasive channel. Furthermore, after expansion, new gaps will inevitably be created, preventing the original filler from contacting the bone tissue and thus failing to promote bone ingrowth. In this application, the drive rod 51 is a hollow rod with a through channel along its axis. During use, it can serve as a bone graft channel 53. By filling it with a highly fluid repair material such as bone cement, the gaps are filled and the support of the central filler is improved. For example, bone fragments or other fillers can be pre-filled in the bone graft space, and after expansion, bone cement can be injected to fill the newly formed gaps.

[0048] Additionally, this application employs a combination of components with mating relationships, without using bolts or other fasteners, which reduces assembly and processing difficulty while ensuring variable angle expansion. Specifically, a multi-level guide structure movably connects the main frame 20 with the upper and lower cover plates 12 into a whole. The multi-level guide structure includes multiple sets of guide blocks and corresponding guide grooves 42. The first guide block 41a and the second guide block 41b are located on both sides of the supporting body 30, and the upper and lower cover plates 12 are provided with corresponding guide grooves 42 at corresponding positions. The third guide block 41c is located at the implanted end and the rear end of the cover plate, and the part of the main frame 20 connected to it is provided with a corresponding guide groove 42.

[0049] The third guide block 41c is located on the opposite side of the first and second guide blocks 41b. Multiple guide blocks limit the movement of the cover plate from multiple angles, keeping it stable and preventing it from shifting during the opening process.

[0050] It should be noted that the terms "first," "second," and "third" are merely distinctions between components in different positions and do not constitute a limitation on the specific number. As shown in the figure, each of the above guide blocks is provided in pairs, and those skilled in the art can adjust them flexibly according to the actual situation.

[0051] In a preferred embodiment, the main frame 20 and the supporting body 30 are rectangular frames / rounded rectangular frames, the first and second guide blocks 41b are located on both sides of the long side of the supporting body 30, and the third guide block 41c is located on both sides of the short side of the main frame 20.

[0052] In a preferred embodiment, the main frame 20 and the supporting body 30 are kidney-shaped frames. In this embodiment, the long side refers to the two sides that are parallel to or at an obtuse angle to the length direction. The length direction is the direction of the line connecting the endpoints with the greatest distance in the projection of the frame on the horizontal plane. The direction perpendicular to the length direction is the short side direction. The first and second guide blocks 41b are located on the two sides that are parallel to or at an obtuse angle to the length direction of the supporting body 30, and the third guide block 41c is located on both sides of the short axis of the main frame 20.

[0053] Furthermore, the second guide block 41b and the first guide block 41a have different slopes, specifically, as follows: Figure 6 As shown, the first guide block 41a and the second guide block 41b have different slopes. Since the first guide block 41a and the second guide block 41b are located on opposite long sides with different slopes, when the opening body 30 moves by the same amount, the guide block with the larger slope has a larger angle with the horizontal plane, and the greater the lifting height. The different slopes of the two sets of guide blocks result in different upward heights of the two long sides, which manifests as a variable angle opening. The third guide block 41c is located on the outer edge of the cover, near the side of the implantation end 25 and the rear end 24. The guide groove 42 that works with it has the same arc-shaped trajectory as the cover plate, which plays a limiting role. For components that are long like the cover plate, lifting them from the middle may cause their edges to wobble. The third guide block 41c stabilizes the unfolding process.

[0054] Correspondingly, such as Figures 7-9 As shown, the slope of the guide groove 42 of the cover is the same as that of the corresponding guide block, so that the guide block can move along the direction of the guide groove 42 without interfering with its movement.

[0055] like Figure 4 As shown, this application can achieve expansion at different angles. Since the main frame 20 itself is tilted, when not expanded, the two cover plates are at a certain angle, α, and the maximum expansion angle is β, as shown. Figures 8-9 As shown, the angle between the first guide block 41a and the plane of the main frame 20 is γ, and the angle between the second guide block 41b and the plane of the main frame 20 is δ. The first guide block 41a is closer to the higher side of the main frame 20, and γ is greater than δ. The supporting body 30 moves the same distance in the plane of the main frame 20. The lifting height of the first guide block 41a side is greater than that of the second guide block 41b side, thereby increasing β.

[0056] Additionally, the opening process in this application is not the traditional pivot-type opening, but rather simultaneous lifting from both sides. The angle is determined by the difference in lifting height. Compared to pivot-type opening, the mechanism of this application is more stable. However, simultaneous lifting from both sides with different lifting heights can easily cause interference, leading to immobility. Existing technologies often match the corresponding parameters of relevant components through a limited number of experiments. In actual production, products often have multiple specifications or even personalized customization requirements. How to quickly determine the corresponding parameters of relevant components without interference remains an unsolved problem.

[0057] Therefore, this application proposes a method for quickly determining the relevant parameters of the expandable angle, combined with the appendix. Figure 4 , Figure 8 , Figure 9 As shown, the maximum angle that can be opened is related to many factors. Based on clinical practice, the applicant has selected the cover plate lifting height H and the distance that the opening body can move L in this application. H and L can be determined by measuring medical imaging data or preoperative planning. The values ​​are relatively easy to obtain and do not require calculation or conversion.

[0058] Based on this, the tilt angle of the guide block that does not cause interference can be quickly determined using the following method.

[0059] , (γ∈(0,90) )

[0060] , (δ∈(0,90) )

[0061] Where H is the lifting height of the cover plate, H1 is the lifting height of the higher side, and H2 is the lifting height of the lower side; L is the movement distance of the supporting body. This is the maximum distance the body can move within the main frame.

[0062] It should be noted that L is not the length of the main frame, such as... Figure 7 As shown, the dashed line represents the position of the unfolded body before movement, and the solid line represents the position of the unfolded body after movement. This shows that the maximum range of motion of the unfolded body is not the length of the main frame, but is limited by the size of the main frame.

[0063] Preferably, H1 ranges from 3 to 10 mm, and H2 ranges from 0 to 1 mm. The range is 0.2~4mm.

[0064] More preferably, H1 ranges from 4 to 8 mm, and H2 ranges from 0 to 0.5 mm; The range is 0.25~3.8mm.

[0065] More preferably, H1 ranges from 4 to 7.5 mm, and H2 ranges from 0 to 0.48 mm; The range is 0.3~3.5mm.

Claims

1. A lateral variable angle cage, characterized by: The utility model relates to a kind of bone expansion device, including: Cover plate, expansion body, main frame, guide structure, driving mechanism; The main frame is the frame body without setting panel on upper and lower end surfaces, and the two ends in the length direction of the main frame are implantation end and rear end respectively, and first through hole and second through hole matched with driving mechanism are arranged on rear end and implantation end respectively;The cover plate includes: upper cover plate, lower cover plate, and upper and lower cover plates cover the upper and lower end surfaces of the main frame; The expansion body is located in the main frame, and is movably connected with the cover plate by guide structure, and the expansion body is driven by the driving device connected therewith, and moves in the plane of the main frame, and the guide structure moves with the expansion body, and drives the upper and lower cover plates to expand; The guide structure includes guide block and guide groove, the direction of the guide groove is same with the inclination direction of the guide block, and the guide block and the guide groove are matched two by two;The guide block is located on the edge of the expansion body, and the guide groove is located on the cover plate, and the guide block on the expansion body is placed in the corresponding guide groove on the cover plate, so that the expansion body and the cover plate are movably connected.

2. The variable angle side portal cage of claim 1, wherein: The guide block includes: first guide block, second guide block and third guide block, the first guide block and the second guide block are located on the opposite sides in the length direction of the expansion body, and the third guide block is located on the two sides of the cover plate close to the implantation end and the rear end, so that the third guide block is located on the different side with the first guide block and the second guide block.

3. The variable angle lateral interbody fusion cage of claim 2, wherein: The inclination angles of the first guide block and the second guide block are different.

4. The variable angle side portal fusion cage of claim 1, wherein: The driving mechanism includes: driving rod, the driving rod passes through the first through hole on the main frame and is threadedly connected with the expansion body, and after implantation, the expansion body is driven to move in the inner frame by rotating the driving rod through thread cooperation.

5. The variable angle lateral interbody fusion cage of claim 4, wherein: Further comprising: Limiting rod, the limiting rod passes through the second through hole on the main frame and is connected with the expansion body, and the direction of the limiting rod is same with the movement direction of the expansion body.

6. The variable-angle side-portal fusion cage of claim 1, wherein: The first through hole can be divided into near mouth section, clamping groove and far mouth section, wherein the near mouth section communicates with the inside of the main frame, the hole diameter of the clamping groove part is larger than that of the near mouth section, the hole diameter of the far mouth section is same with that of the clamping groove, and the far mouth section is provided with thread; Correspondingly, the driving rod is provided with adjusting section and limiting section, and in assembly, the limiting section is screwed into the clamping groove of the first through hole.

7. The variable-angle side-approach interbody fusion cage of claim 6, wherein: The driving rod is hollow rod body, and the axis position is provided with through channel, which is used as bone graft channel in use.

8. The variable-angle side-portal fusion cage of claim 1, wherein: The cover plate is provided with a plurality of hollow areas, the edge of the hollow area is closed figure, and the hollow area is provided with porous structure, which is formed by 3D printing technology, and is similar to the porous structure of human bone trabecula.

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