Interbody fusion cage

Abstract

The utility model provides an interbody fusion cage which comprises a body and threads formed on the outer surface of the body, and is characterized in that the interbody fusion cage is provided with an opening groove used for containing bone grafting materials, the opening groove is spirally arranged along the outer surface of the interbody fusion cage, the interbody fusion cage comprises a front end portion and a rear end portion, the front end portion is in a circular truncated cone shape, and the rear end portion is in a circular truncated cone shape. The rear end part is cylindrical, the threaded teeth of the front end part are provided with front end threaded tooth tips pointing to the front end, and the threaded teeth of the rear end part are provided with rear end threaded tooth tips pointing to the rear end. Therefore, the correct distance between the upper vertebral body and the lower vertebral body is guaranteed, and meanwhile bony fusion between the vertebral bodies is effectively promoted.

Description

Technical Field

[0001] This utility model relates to the field of fusion device technology, specifically to an intervertebral fusion device for minimally invasive endoscopic spinal surgery. Background Technology

[0002] Interbody fusion cages are typically made of alloy or polyetheretherketone (PEEK) material and are implanted between two vertebrae during surgery. Simultaneously, autologous bone, allogeneic bone, or osteogenic materials are implanted between the vertebrae to maintain the necessary space and promote bony fusion. Interbody fusion cages maintain intervertebral disc height, reduce nerve root pressure, and maintain vertebral stability, and are widely used in the treatment of conditions such as herniated discs, spinal stenosis, and degenerative spinal diseases.

[0003] Chinese patent CN104970906A discloses an interbody fusion device. For example... Figure 1 As shown, the intervertebral fusion device includes a body, which includes a cavity 1. The cavity is a cuboid with an arc-shaped advancing end 2 at one end and an advancing end 3 at the other end. A pair of sides of the cavity 1 have a central large opening 11, and another pair of sides have side openings 12. The central large opening 11 is shaped like a racetrack, with a rectangular middle section. Each end of the rectangle is connected to a semicircle, and several outward-facing protrusions 13 are provided on both sides of the middle section. The advancing end 3 has a trapezoidal cross-section parallel to the plane of the side openings 12, including a common surface with the cavity 1, a rear end surface, and a side surface connecting the surface of the central large opening 11 and the rear end surface. Both the common surface and the rear end surface have screw holes 31. During the procedure, the operating tool is inserted into the screw holes and tightened. Then, the body is placed between the two vertebrae using the operating tool, so that the surfaces of the two central large openings 11 of the body contact the vertebral end faces. Bone graft material is then implanted through the side openings 12, and the operating tool is then removed.

[0004] The aforementioned intervertebral fusion device has a roughly rectangular prism-shaped fusion device body, which has the advantages of a large vertebral support surface and strong postoperative stability. However, during the operation, because the fusion device needs to be pushed between the two vertebrae, the protrusions on the upper and lower surfaces of the fusion device body come into contact with the vertebrae and generate a large frictional force. Due to the existence of the above frictional force, the two vertebrae may not reach the ideal postoperative intervertebral space position, and may even lead to nerve damage and affect the blood supply of the bony endplates of the vertebrae.

[0005] Korean patent KR1020040064577A discloses a flexible interbody fusion device. For example... Figure 2As shown, the intervertebral fusion device is a cylindrical helix 102, having a convex, rounded portion A providing support and a radially extending portion B with a hollow core. The convex portion A has a helical head 103, and the radially extending portion B has four slits 106 extending to its ends. These four slits divide the radially extending portion B into four independent hollow discs 104. The outer surface of the radially extending portion B is threaded, allowing the hollow core to be smoothly inserted into the intervertebral space for fixing and supporting adjacent vertebrae. The four slits can be used not only to adjust the diameter of the cylindrical helix but also to implant bone graft material to promote intervertebral bony fusion.

[0006] The aforementioned flexible intervertebral fusion cage has a cylindrical shape, allowing for convenient surgical implantation by rotating the cage. Compared to the traditional push-in implantation method, this is easier to operate and allows for precise fixation of the two vertebrae to the optimal position during surgery. However, because the bone graft material fuses the two vertebrae through two vertical slits in the fusion cage, there is a possibility that the slits may not align with the contact surfaces of the upper and lower vertebrae at the final implantation position. Although markings corresponding to the slit positions can be made on the end face of the fusion cage preoperatively, and these markings can be used during implantation to determine if the slits are aligned with the contact surfaces of the upper and lower vertebrae, thus determining if the slits have reached the optimal position where the bone graft material can contact both vertebrae, this method not only increases the number of surgical steps but also may result in a conflict between the optimal position of the cylindrical fusion cage during insertion into the intervertebral space and the optimal position of the slits. Utility Model Content

[0007] The purpose of this invention is to provide an intervertebral fusion device that not only allows for convenient and accurate implantation of the device during surgery, but also enables the bone graft material to accurately contact the surfaces of the upper and lower vertebrae, thereby ensuring that the upper and lower vertebrae maintain the correct spacing while effectively promoting intervertebral bony fusion.

[0008] This utility model provides an intervertebral fusion device, which includes a body and a thread formed on the outer surface of the body. The intervertebral fusion device has an opening groove for receiving bone graft material, and the opening groove is spirally arranged along the outer surface of the intervertebral fusion device.

[0009] Preferably, the opening groove includes a bottom and a side, and its cross-section is U-shaped; the depth of the opening groove is greater than the height of the thread teeth.

[0010] Preferably, there are multiple opening slots, which are spaced apart by spacer teeth.

[0011] Preferably, the number of the above-mentioned opening slots is 2-5.

[0012] Preferably, the interbody fusion device includes an anterior end and a posterior end, wherein the anterior end is frustum-shaped and the posterior end is cylindrical.

[0013] Preferably, the opening groove is only provided on the rear end.

[0014] Preferably, the threaded teeth at the front end include a front threaded tooth root and a front threaded tooth tip, the front threaded tooth tip having a front threaded tooth tip pointing towards the front end.

[0015] Preferably, the threaded tooth at the rear end includes a rear threaded tooth root and a rear threaded tooth tip, the rear threaded tooth tip having a rear threaded tooth tip pointing towards the rear end.

[0016] The aforementioned intervertebral fusion device can not only be conveniently implanted in the accurate position during surgery, allowing the bone graft material to accurately contact the surfaces of the upper and lower vertebral bodies, but also prevent the fusion device from shifting due to vibration or other reasons after surgery. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of an existing interbody fusion device.

[0018] Figure 2 This is a schematic diagram of an existing flexible interbody fusion device.

[0019] Figure 3 This is a schematic diagram of the interbody fusion device provided in the embodiments of this application.

[0020] Figure 4 This is a cross-sectional view of the interbody fusion device provided in the embodiments of this application.

[0021] Figure 5 This is a partially enlarged view of the front spiral teeth of the interbody fusion device provided in the embodiments of this application.

[0022] Figure 6 This is a partially enlarged view of the rear helical teeth of the interbody fusion device provided in the embodiments of this application.

[0023] Wherein: 1: cavity, 2: forward end, 3: advance end, 4: thread, 5: filling groove, 6: dividing block, 7: through hole, 8: tail, 9: head, 10: tool slot, 102: cylindrical helix, 103: helix head, 104: hollow disk, 106: slit, 401: root of front helical tooth, 402: tip of front helical tooth, 403: tip of front threaded tooth, 404: root of rear helical tooth, 405: tip of rear helical tooth, 406: tip of rear threaded tooth, I: fusion unit, II: partial magnification of front helical tooth, III: partial magnification of rear helical tooth, A: rounded convex part, B: radial extension part, C: front end of fusion unit, D: rear end of fusion unit. Detailed Implementation

[0024] Exemplary embodiments of the present application will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application may be implemented in various forms and should not be limited to the specific embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present application and to fully convey the scope of the disclosure of the present application to those skilled in the art.

[0025] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of this application. However, it will be apparent to those skilled in the art that this application can be practiced without one or more of these details. In other instances, to avoid confusion with this application, some technical features well-known in the art have not been described; that is, not all features of actual embodiments are described herein, nor are well-known functions and structures described in detail.

[0026] In the accompanying drawings, for clarity, the dimensions of layers, areas, and elements, as well as their relative dimensions, may be exaggerated. The same reference numerals denote the same elements throughout.

[0027] Figure 3 This is a schematic diagram of the interbody fusion device provided in an embodiment of this application. The interbody fusion device I includes a body and threads 4 formed on the outer surface of the body. The body has a front end face 9 and a rear end face 8, wherein the diameter of the front end face 9 is smaller than the diameter of the rear end face 8. In a preferred embodiment, the front end face 9 is configured to bulge forward in the middle. This bulging of the front end face allows the interbody fusion device to be smoothly inserted into the intervertebral space. After insertion, the threads 4 on the outer side of the body engage with the surface of the bony endplate of the adjacent vertebral body, allowing the interbody fusion device to be smoothly screwed between the two vertebral bodies.

[0028] exist Figure 3 In the middle, the interbody fusion device I has an opening groove 5, which is spirally arranged along the outer surface of the interbody fusion device I, combined with Figure 4 As can be seen, the opening groove includes a bottom and sides, and its cross-section is U-shaped. The depth of this U-shaped opening groove is greater than the height of the teeth of thread 4, and its bottom is parallel to the central axis aa of the intervertebral fusion cage. Opening groove 5 is used to accommodate bone graft material. In traditional similar... Figure 2The interbody fusion cage shown also has an opening groove, which is set only at two positions above and below the interface along the longitudinal axis of the fusion cage. In order to ensure that the bone graft material can make contact with the adjacent upper and lower vertebral bodies when the conventional interbody fusion cage is screwed into its final position, the conventional operation method is to mark the bottom of the fusion cage before the operation. This mark is, for example, a straight line, which is consistent with the position of the groove on the fusion cage that accommodates the bone graft material. In this way, when the fusion cage is screwed between the adjacent vertebral bodies, the direction of the straight line marked is perpendicular to the adjacent surfaces of the upper and lower vertebral bodies. It can be considered that the bone graft material of the fusion cage is in contact with the upper and lower surfaces of the vertebral bodies, thereby enabling the upper and lower vertebral bodies to fuse through the bone graft material. However, the above-described procedure has a problem. When the interbody fusion cage is rotated to its final position (usually within 180 degrees), and the marked line is already perpendicular to the adjacent surfaces of the vertebrae above and below, the operator faces a dilemma: if they continue rotating the cage to the final position, the marked line will no longer be perpendicular to the adjacent surfaces of the vertebrae. This means the bone graft material on the cage will not be in contact with the vertebrae. This procedure forces the operator to choose between the cage reaching its final position and the bone graft material making contact with the upper and lower surfaces of the vertebrae, a dilemma that obviously affects the surgical outcome.

[0029] The fusion device with a spiral-shaped opening groove proposed in this invention solves the aforementioned problems. In this invention, the spirally shaped opening groove is used to accommodate bone graft material. When the operator screws the fusion device between the two vertebral bodies, at any position after screwing it in, the bone graft material in the spirally shaped opening groove is in contact with the adjacent surfaces of the two vertebral bodies. Therefore, the operator not only does not need to mark a straight line before surgery, but can also rotate the fusion device to the optimal position according to the surgical requirements, at which the bone graft material in the spirally shaped opening groove can obviously contact the upper and lower surfaces of the vertebral bodies.

[0030] Combination Figure 3 As can be seen, the spirally arranged opening slots 5 can be spaced out. These spaced opening slots are separated by spacer teeth 6. The number of spaced opening slots can be selected according to the length of the fusion unit, typically 2-5. In this arrangement, the bone graft material is filled into different opening slots. This segmented filling of the bone graft material in the fusion unit improves the contact force between the bone graft material and the fusion unit, making it less likely for the bone graft material to fall out of the fusion unit. Obviously, the processing method of the spiral opening slots is as follows: first, threads 4 are machined on the fusion unit body, and then the opening slots 5 are spirally cut on the threaded body. If necessary, the opening slots 5 are spaced out.

[0031] Combination Figure 4The intervertebral fusion cage is roughly divided into a posterior end C and an anterior end D. The anterior end D is roughly frustum-shaped, and the posterior end C is roughly cylindrical. When the fusion cage is screwed between adjacent vertebrae, the conical shape of the anterior end D allows for easier insertion. In the final position of the fusion cage, the posterior end C is also positioned between adjacent vertebrae. Thus, the support provided by the posterior end C maintains a predetermined distance between the adjacent vertebrae. It is evident that the spiral opening groove 5 can be provided only on the posterior end C to ensure sufficient contact between the bone graft material in the opening groove and the surface of the adjacent vertebrae.

[0032] Figure 5 This is an enlarged view of a portion II of the threaded teeth at the front end D. The threaded teeth at the front end include a front threaded tooth root 401 and a front threaded tooth tip 402. As can be seen from the figure, the front threaded tooth root 401 has a front end and a rear end, with the front end being more gently sloping than the rear end; the front threaded tooth tip 402 is roughly horizontal in shape and has a front threaded tooth tip 403 pointing towards the front end.

[0033] Figure 6 This is an enlarged view of a portion III of the threaded tooth at the rear end C. The threaded tooth at the rear end includes a rear threaded tooth root 404 and a rear threaded tooth tip 405. As can be seen from the figure, the rear threaded tooth root 404 is generally tapered, and the rear threaded tooth tip 405 includes a front end and a rear end, with the rear end being more gently sloping than the front end; the rear threaded tooth tip 405 has a rear threaded tooth tip 406 pointing towards the rear end.

[0034] By using the different settings of the anterior and posterior threaded teeth, when the fusion device is screwed into the intervertebral space, the forward-inclined tips of the anterior threaded teeth can facilitate the screwing of the fusion device into the vertebral body. When the fusion device is screwed into a certain depth and the posterior threaded teeth contact the adjacent vertebral body, the slightly backward-inclined tips of the posterior threaded teeth can, on the one hand, allow the fusion device to be screwed into the designated position smoothly, and on the other hand, prevent the fusion device from shifting due to vibration or other reasons after surgery.

[0035] The intervertebral fusion device also includes a tool slot 10 and a through hole 7. The tool slot 10 is used to cooperate with a rotating tool, and the fusion device is screwed into the space between adjacent vertebrae by rotating the rotating tool. The through hole 7 is used to connect with a holder.

[0036] It should be understood that the phrases "in embodiments of this application" or "in some embodiments" throughout the specification mean that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this application. Therefore, "in embodiments of this application" or "in some embodiments" appearing throughout the specification do not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. It should be understood that in the various embodiments of this application, the sequence numbers of the above-described processes do not imply a sequential order of execution; the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application. The sequence numbers of the above-described embodiments are merely descriptive and do not represent the superiority or inferiority of the embodiments.

[0037] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An intervertebral cage comprising a body and a thread formed on an outer surface of the body, characterized in that, The aforementioned interbody fusion device has an opening groove for receiving bone graft material. The opening groove is spirally arranged along the outer surface of the interbody fusion device. The opening groove includes a bottom and a side, and its cross-section is U-shaped. The depth of the opening groove is greater than the height of the thread teeth. There are multiple opening grooves, which are spaced apart by spacer teeth. The aforementioned interbody fusion device includes a front end and a rear end. The front end is frustum-shaped, and the rear end is cylindrical. The opening groove is only provided on the rear end.

2. The intervertebral cage of claim 1, wherein, The number of the above-mentioned opening slots is 2-5.

3. The intervertebral cage of claim 1, wherein, The threaded teeth at the front end include a front threaded tooth root and a front threaded tooth tip, the front threaded tooth tip having a front threaded tooth tip pointing towards the front end.

4. The intervertebral implant as recited in claim 1, wherein, The threaded teeth at the rear end include a rear threaded tooth root and a rear threaded tooth tip, the rear threaded tooth tip having a rear threaded tooth tip pointing towards the rear end.

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