Lateral zero-profile intervertebral fusion fixation device for lumbar spine

Abstract

This utility model provides a lateral zero-notch interbody fusion fixation device for the lumbar spine, relating to the field of medical devices. The fixation device includes a support body and at least four fixation members. The support body is wedge-shaped, with a through hole in the middle of its inclined surface. One end of the support body has an implantation guide, and the other end has at least four inclined threaded countersunk holes. The four fixation members are divided into two groups, each group passing through the threaded countersunk holes into the support body and extending obliquely towards the upper and lower end faces of the support body facing the adjacent vertebral body. Two fixation members facing the same side have different inclination angles, forming a non-coplanar interlocking fixation structure between the four fixation members and the vertebral body. This application enables oblique lateral interbody fusion with bone grafting and internal fixation, further improving interbody stability. It allows OLIF (Lumbar Interbody Fusion) to achieve internal fixation and interbody fusion device implantation in a single surgery, with good vertebral body compatibility, low risk of loosening or dislodgement, and stable implantation.

Description

Technical Field

[0001] This utility model relates to the field of medical devices, specifically to a lumbar lateral zero-notch interbody fusion fixation device. Background Technology

[0002] Oblique lateral interbody fusion (OLIF) is widely used in clinical practice due to its advantages such as minimal trauma, less bleeding, no entry into or interference with the spinal canal, good indirect decompression, rapid recovery, and high fusion rate. However, the interbody fusion cages used in OLIF still carry the risk of bone graft nonfusion and displacement. To maintain the position of the fusion cage, promote interbody fusion, and maintain spinal stability, lateral rod-and-screw fixation or posterior pedicle screw fixation systems are often used after fusion cage implantation.

[0003] However, using a lateral interbody fusion cage followed by posterior pedicle screw fixation requires changing the patient's position and performing secondary disinfection, making the procedure complex, time-consuming, and prone to complications. If a lateral approach with a screw-rod system is used, the protruding screw caps and rods can easily irritate the psoas muscle due to its strong muscles, potentially causing nerve damage and postoperative hip flexion weakness or intractable femoral pain. Furthermore, existing interbody fusion cages often have poor vertebral body fit, making fusion difficult, prone to sinking and failure, and increasing the likelihood of postoperative loosening and withdrawal complications. Utility Model Content

[0004] The purpose of this invention is to provide a lateral zero-notch interbody fusion fixation device for the lumbar spine, which can perform interbody support bone grafting and internal fixation from the oblique side, thereby further improving the stability of the intervertebral disc. This allows OLIF to achieve internal fixation and interbody fusion device implantation in a single surgery, with good matching with the vertebral body, making it less prone to loosening and dislocation, and ensuring stable implantation.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows:

[0006] A lumbar lateral zero-notch interbody fusion fixation device for installation between two adjacent superior and inferior vertebral bodies in the lumbar spine, comprising a support body and at least four fixation components;

[0007] The support body is wedge-shaped, with a through hole in the middle of its inclined surface; the end of the support body adjacent to its large and small ends is provided with an implantation guide, and the end opposite to the implantation guide is provided with at least four inclined threaded countersunk holes.

[0008] The four fasteners are divided into two groups. The two groups of fasteners pass through the threaded countersunk holes into the support body and extend obliquely toward the upper and lower end faces of the support body facing the adjacent vertebral body for connection with the vertebral body. Among them, the two fasteners facing the same side have different inclination angles, so that the four fasteners and the upper and lower vertebral bodies form a non-coplanar interlocking fastening structure.

[0009] Furthermore, in this invention, the included angle between the upper and lower end faces of the support body facing the adjacent vertebrae is 6±0.5°.

[0010] Furthermore, in this invention, the implantation guide is wedge-shaped, and the height of its end away from the support is lower than the height of its end near the support.

[0011] Furthermore, in this utility model, the two fixing members facing the same side are a first self-locking screw and a second self-locking screw, wherein the diameter of the first self-locking screw is smaller than that of the second self-locking screw; the angle between the first self-locking screw and the adjacent vertebral endplate is 10°-30°; and the angle between the second self-locking screw and the adjacent vertebral endplate is 30°-60°.

[0012] Furthermore, in this invention, the end of the support body away from the implantation guide is rotatably provided with an anti-retraction locking piece, which is used to limit and block the heads of the four fixing members.

[0013] Furthermore, in this utility model, the support body and the implantation guide are integrally formed and are made of PEEK material; the fixing component is made of PEEK material or metal material; and the anti-reverse locking plate is made of titanium-nickel alloy material.

[0014] Furthermore, in this invention, the support body has a wing extending toward two adjacent vertebral segments at one end edge away from the implantation guide.

[0015] Furthermore, in this utility model, the upper and lower end faces of the support are respectively provided with tooth-like structures distributed around the through hole. The tooth-like structures include cross teeth and oblique teeth, wherein the cross teeth are provided near the two ends of the support in the implantation direction.

[0016] Furthermore, in this utility model, a crossbeam is provided inside the through hole.

[0017] Furthermore, in this invention, the support body and the implantation guide are provided with a plurality of micropores on their two sides adjacent to each other; the micropores are connected to the through holes; and the two sides are respectively coated with a tantalum metal bioactive coating covering the micropores.

[0018] This utility model has at least the following advantages or beneficial effects:

[0019] This invention features a support body and at least four fixators. The wedge-shaped support body is used to support adjacent vertebrae, and its inclined surface adapts to the tilt of the lumbar spine, facilitating the restoration of the physiological curvature of the lumbar spine. A through hole is provided in the middle of the inclined surface of the support body for implanting a bone graft, enhancing fusion with the vertebrae. One end of the support body has an implantation guide, which guides the rapid implantation between the vertebrae. The other end has at least four inclined threaded countersunk holes. The four fixators are divided into two groups, which pass through the threaded countersunk holes into the support body and extend obliquely towards the upper and lower end faces of the adjacent vertebrae, allowing the fixators to be fixedly connected to the upper and lower vertebrae respectively. The countersunk hole design avoids irritation of surrounding tissues by the implant, reducing postoperative psoas muscle irritation-related complications. The two fixators facing the same side have different tilt angles, forming a non-coplanar interlocking fixation structure between the four fixators and the upper and lower vertebrae, achieving immediate three-dimensional fixation and minimizing displacement of the fusion device in all dimensions of the intervertebral space. This application enables oblique lateral intervertebral support bone grafting and internal fixation, further improving intervertebral stability. This allows OLIF to achieve internal fixation and intervertebral fusion device implantation in a single surgery, with good matching with the vertebral body, making it less prone to loosening and dislocation, and ensuring stable implantation. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A schematic diagram of the lumbar lateral zero-notch interbody fusion fixation device provided in the application embodiment;

[0022] Figure 2 A side sectional view of the support provided in the embodiment of the application;

[0023] Figure 3 A side sectional view of the support provided for another embodiment of the application.

[0024] Reference numerals: 1-Support body, 11-Through hole, 12-Implant guide, 13-Threaded countersunk hole, 14-Wing plate, 15-Cross countersunk teeth, 16-Angled countersunk teeth, 17-Crossbeam, 18-Micro hole, 2-Fixing component, 21-First self-locking screw, 22-Second self-locking screw, 3-Anti-reverse locking plate. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0026] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0027] Please refer to Figures 1-3 The figure shown is a schematic diagram of the lumbar lateral zero-notch intervertebral fusion fixation device in an embodiment of this utility model.

[0028] like Figure 1This embodiment provides a lumbar lateral zero-notch intervertebral fusion fixation device for installation between two adjacent superior and inferior vertebrae in the lumbar spine. It comprises a support body 1 and at least four fixation components 2, which are detachable and adaptable to form a complete fusion device, avoiding the cumbersome surgical procedures caused by separate, unrelated implantation and fixation components. Both the support body 1 and the fixation components 2 can be 3D printed, facilitating individualized design and fabrication. Clinical applications can be customized to match different individuals and vertebral segments. The support body 1 is wedge-shaped and is implanted between two adjacent vertebrae to support them. Its wedge-shaped structure allows the end face in contact with the vertebra to be inclined, improving the fit and facilitating vertebral fusion, while also evenly distributing the load. A through hole 11 is provided in the middle of the inclined surface of the support body 1 for implanting a bone graft to enhance fusion between the superior and inferior vertebrae. The support body 1 has an implantation guide 12 at one end adjacent to its larger and smaller ends. The implantation guide 12 guides the support body 1 during implantation and can expand the vertebral body to facilitate rapid implantation between the upper and lower vertebral bodies. The support body 1 has at least four inclined threaded countersunk holes 13 at the opposite end to the implantation guide 12. The four fixation members 2 are divided into two groups, which pass through the threaded countersunk holes 13 into the support body 1 and extend obliquely towards the upper and lower end faces of the support body 1 facing the adjacent vertebral bodies, achieving a fixed connection with the upper and lower vertebral bodies. Furthermore, the countersunk hole design avoids psoas muscle irritation caused by protruding caps and pins, and also avoids stimulation of surrounding tissues by the implant, reducing postoperative complications related to psoas muscle irritation. Among them, the two fixation members 2 facing the same side are tilted at different angles, so that the four fixation members 2 form a non-coplanar interlocking fixation structure with the upper and lower vertebral bodies, achieving an immediate three-dimensional fixation effect and providing multi-dimensional stability; at the same time, the non-co-directional structure of the upper and lower surfaces can prevent the fusion device from dislodging and shifting to the left and right, providing high stability and maximizing the prevention of displacement of the fusion device in all dimensions of the intervertebral space.

[0029] In this embodiment, four fasteners 2 are preferably provided to ensure stable connection while reducing weight and frequency of operation. The number can also be increased according to actual needs.

[0030] like Figure 2 As an example, the angle between the upper and lower end faces of the support 1 facing the adjacent vertebra is 6±0.5°, which matches the physiological curvature of the lumbar spine and can effectively restore the physiological curvature of the lumbar spine.

[0031] As an example, the aforementioned implantation guide 12 is wedge-shaped, with the height of its end away from the support body 1 being lower than the height of its end near the support body 1. That is, the portion from its implanted head to the support body 1 has a gradually expanding shape, which allows it to self-open the intervertebral space during implantation, protecting the vertebral endplate while facilitating implantation.

[0032] As an example, the two fixing members 2 facing the same side are a first self-locking screw 21 and a second self-locking screw 22, wherein the diameter of the first self-locking screw 21 is smaller than that of the second self-locking screw 22; the angle between the first self-locking screw 21 and the adjacent vertebral endplate is 10°-30°; the angle between the second self-locking screw 22 and the adjacent vertebral endplate is 30°-60°; and the tilt angle of the first self-locking screw 21 is smaller than that of the second self-locking screw 22. Figure 1 The thinner and longer screws have a smaller inclination angle to the support body 1 than the thicker and shorter screws. During implantation, the first self-locking screw 21 is first connected to the vertebral body and implanted from the front end (small end) of the support body 1. Due to its length, thinness, and larger angle, it can achieve a stable connection with the vertebral body and avoid cracking at the small end due to excessive thickness. Next, the second self-locking screw 22 is implanted from the rear end (large end) of the support body 1. Its inclination angle is smaller and its diameter is larger, which can serve as an auxiliary fixing force for the first self-locking screw 21, improving the connection strength between the large end of the support body 1 and the vertebral body, and improving stability within a small range of adjacent vertebral bodies. The four self-locking screws, which are inserted vertically, form a non-coplanar interlocking fixation, greatly improving the connection stability between the fusion device and the vertebral body.

[0033] Furthermore, both the first self-locking screw 21 and the second self-locking screw 22 are double-threaded screws, meaning they have two separate helical lines, which improves implantation speed and increases initial stability. The tail end of the double-threaded screw features a gradually increasing thread density zone; as the screw is screwed in to its end, the thread density increases, tightening the connection with the vertebrae and enhancing its stability. The threads of the double-threaded screw are trapezoidal, with a tooth crest width to tooth height ratio of 1:1.2 to 1:1.5. After implantation, the thread taper difference generates an axial preload of 50-150N, achieving self-locking pressure fixation between the upper and lower vertebrae and the fusion cage, allowing for automatic pressure locking of the upper and lower vertebrae and the fusion cage after implantation. By using self-locking pressure screws to lock the upper and lower vertebrae to the implant, postoperative subsidence is significantly reduced.

[0034] As an example, the end of the support 1 furthest from the implantation guide 12 is rotatably fitted with an anti-retraction locking plate 3, which is used to limit and block the heads of the four fixing members 2. That is, it can prevent the self-locking screws from being pushed out and avoid the fusion device from becoming loose.

[0035] Specifically, the head of the anti-reverse locking plate 3 can be oval-shaped, or the edge of the head of the anti-reverse locking plate 3 can be provided with an enlarged portion extending in the opposite direction to the four self-locking screws, so as to limit and block the four self-locking screws. The anti-reverse locking plate 3 can be threaded through the middle of the end of the support body 1, or it can be snapped onto the end of the support body 1, or other existing conventional technical means can be used to prevent the screws from retracting and loosening.

[0036] As an example, the aforementioned support 1 and implantation guide 12 are integrally molded from PEEK material. The trabecular bone structure is simulated through 3D printing, eliminating the need for additional metal fixation components, greatly simplifying the procedure, saving surgical time, and reducing bleeding. Furthermore, PEEK material has the same mechanical properties as human bone, avoiding stress shielding at the bone-material interface and preventing postoperative collapse. This solves the problems of mismatch between the mechanical strength of metal materials or metal-PEEK hybrid zero-notch fusion devices and human bone, leading to postoperative endplate collapse and sinking. The fixation component 2 can be made of PEEK or metal, depending on the requirements. The aforementioned anti-retraction locking plate 3 can be made of titanium-nickel alloy. Titanium-nickel alloy is in the austenitic phase at body temperature (~37℃) and has a recoverable strain capacity of 6-8%. When the screw is subjected to vibration or fretting, the anti-retraction locking plate 3 can absorb energy through elastic deformation and return to its original shape after the external force is removed, maintaining a constant locking force.

[0037] As an example, the support 1 has a wing 14 extending toward the two adjacent vertebral bodies at one end edge away from the implantation guide 12. After the support 1 is implanted, the wing 14 is pressed against the surface of the vertebral bone, preventing the fusion device from being driven too deep and thus preventing it from entering the spinal canal and compressing the nerves.

[0038] As an example, the upper and lower end faces of the aforementioned support 1 are respectively provided with tooth-like structures distributed around the through hole 11. The tooth-like structures include cross-shaped inverted teeth 15 and oblique inverted teeth 16, wherein the cross-shaped inverted teeth 15 are provided at both ends near the implantation direction of the support 1. That is, the upper and lower end faces of the support 1 adopt a non-unidirectional tooth-like pattern (front and rear inverted teeth, and oblique teeth on both sides) structure. After implantation, the fusion device can achieve a stabilizing effect in all directions, preventing the support 1 from moving backward and ensuring initial stability.

[0039] As an example, a crossbeam 17 is provided within the aforementioned through hole 11. The crossbeam 17 can be a beam plate, which is connected to the opposite inner wall of the through hole 11, forming an I-shaped structure with the inner wall of the through hole 11, such as... Figure 2 The crossbeam 17 can also be an I-beam plate, which is directly fixed in the through hole 11, such as... Figure 3 The I-beam crossbeam design enhances the strength of the fusion device and provides support and fixation for the bone graft, reducing the risk of the graft falling off during surgery and facilitating bone graft fusion.

[0040] As an example, the support 1 and the implantation guide 12 are provided with a plurality of micropores 18 on their two adjacent sides. The micropores 18 are connected to the through holes 11. The micropores 18 on the sides can serve as blood circulation pores, facilitating blood vessel growth and promoting the growth of bone trabeculae, thus promoting long-term fusion. Multiple micropores 18 can be arranged in an array to form a porous array on the sides. Both sides are coated with a tantalum bioactive coating covering the micropores 18, which can maximize the osteoconduction and osteoinduction properties of the fusion device and promote intervertebral fusion. Furthermore, the surface gaps formed by coating the tantalum bioactive coating on the array of micropores 18 facilitate coating filling, improving coating adhesion, promoting osteointegration and osteoinduction of the fusion device, helping to promote bone healing, and avoiding the risk of fusion surgery failure.

[0041] The beneficial effects of the embodiments of this application are as follows:

[0042] This device takes into full account the characteristics of OLIF surgery. By utilizing the stability of the fusion device itself and the self-tapping locking internal fixation screws, it avoids the trauma caused by posterior pedicle screw implantation and also avoids the irritation of soft tissues such as the psoas major muscle caused by the lateral approach rod system.

[0043] The support component 1 and fixing screws of this device are designed with self-tapping properties, facilitating easy implantation and avoiding complications such as spinal cord concussion caused by external force insertion of traditional interbody fusion devices. The head of the support component 1 features a conical design for easy delivery and implantation of the fusion device. The toothed groove design on the upper and lower end faces of the fusion device increases its stability and prevents it from coming out. Several I-beam-shaped crossbeams 17 are added inside the fusion device to prevent bone fragments from falling out of the bone graft groove and to increase the stability of the fusion device.

[0044] The support component 1 of this device adopts a 3D-printed simulated trabecular bone structure, and at the same time, it adds a micropore 18 design to facilitate blood vessel growth in the lateral direction. With the addition of a tantalum metal coating on the surface, it can maximize the bone conduction and bone induction performance of the fusion device and promote intervertebral fusion.

[0045] The device uses inclined screws to fix the support body 1 to the adjacent vertebral body, ensuring the stability of the prosthesis. In addition, the screws are countersunk, which avoids the implant from irritating the surrounding tissues and reduces postoperative complications related to psoas muscle irritation.

[0046] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A lumbar lateral zero-notch interbody fusion fixation device, used for installation between two adjacent superior and inferior vertebral bodies in the lumbar spine, characterized in that, Includes a support structure and at least four fasteners; The support body is wedge-shaped, with a through hole in the middle of its inclined surface; the end of the support body adjacent to its large and small ends is provided with an implantation guide, and the end opposite to the implantation guide is provided with at least four inclined threaded countersunk holes. The four fasteners are divided into two groups. The two groups of fasteners pass through the threaded countersunk holes into the support body and extend obliquely toward the upper and lower end faces of the support body facing the adjacent vertebral body for connection with the vertebral body. Among them, the two fasteners facing the same side have different inclination angles, so that the four fasteners and the upper and lower vertebral bodies form a non-coplanar interlocking fastening structure.

2. The lumbar lateral zero-notch interbody fusion fixation device according to claim 1, characterized in that, The included angle between the upper and lower end faces of the support facing the adjacent vertebra is 6±0.5°.

3. The lumbar lateral zero-notch interbody fusion fixation device according to claim 1, characterized in that, The implantation guide is wedge-shaped, with the height of the end furthest from the support being lower than the height of the end closest to the support.

4. The lumbar lateral zero-notch interbody fusion fixation device according to claim 1, characterized in that, The two fixing components facing the same side are a first self-locking screw and a second self-locking screw, wherein the diameter of the first self-locking screw is smaller than that of the second self-locking screw; the angle between the first self-locking screw and the adjacent vertebral endplate is 10°-30°; and the angle between the second self-locking screw and the adjacent vertebral endplate is 30°-60°.

5. The lumbar lateral zero-notch interbody fusion fixation device according to claim 4, characterized in that, The end of the support body away from the implantation guide is rotatably fitted with an anti-retraction locking plate, which is used to limit and block the heads of the four fixing members.

6. The lumbar lateral zero-notch interbody fusion fixation device according to claim 5, characterized in that, The support and the implantation guide are integrally formed and are made of PEEK material; the fixing component is made of PEEK material or metal; the anti-retraction locking plate is made of titanium-nickel alloy.

7. The lumbar lateral zero-notch interbody fusion fixation device according to claim 1, characterized in that, The support body has a wing extending toward the two adjacent vertebral segments at one end edge away from the implantation guide.

8. The lumbar lateral zero-notch interbody fusion fixation device according to claim 1, characterized in that, The upper and lower end faces of the support are respectively provided with tooth-like structures distributed around the through hole. The tooth-like structures include cross teeth and oblique teeth, wherein the cross teeth are provided at both ends close to the implantation direction of the support.

9. The lumbar lateral zero-notch interbody fusion fixation device according to claim 1, characterized in that, A crossbeam is installed inside the through hole.

10. The lumbar lateral zero-notch interbody fusion fixation device according to claim 1, characterized in that, The support body has several micropores on its two sides adjacent to the implantation guide; the micropores are connected to the through holes; and the two sides are coated with a tantalum metal bioactive coating covering the micropores.

Images