Expandable interbody fusion cage

Abstract

The expandable interbody fusion cage comprises an acetabular cup and a titanium cage, the interior of the acetabular cup is hollow, and the titanium cage is installed in the acetabular cup; the acetabular cup comprises a left shell and a right shell which are symmetrically arranged, the left shell and the right shell are respectively provided with a plurality of vertical columns which are vertically arranged, the front ends of the left shell and the right shell are respectively provided with an I-shaped frame, a certain gap is formed between the middle portions and the rear ends of the left shell and the right shell, and clamping sawteeth are arranged on the upper faces and the lower faces of the middle portions of the left shell and the right shell respectively. A flexible supporting column and a bridging column are installed in a gap between the left shell and the right shell, and the acetabular cup expands in the left-right direction through the I-shaped frame, the flexible supporting column and the bridging column. The front end of the titanium cage is conical, a limiting groove matched with the I-shaped frame is formed in the conical front end, a bone grafting cavity is formed in the middle of the titanium cage, the upper side and the lower side of the bone grafting cavity are open, and a plurality of hollow holes are formed in the cage wall of the titanium cage. The interbody fusion cage is reasonable in structure, stability and anti-settling performance can be improved, and therefore certain help and guidance are provided for clinic.

Description

Technical Field

[0001] This utility model belongs to the field of medical device technology, specifically relating to an expandable interbody fusion device. Background Technology

[0002] Degenerative lumbar spine diseases are common and frequently occurring orthopedic conditions that severely impact patients' basic lives and work. Many patients with severe symptoms require surgery to relieve compression and restore stability. Lumbar interbody fusion surgery includes anterior lumbar interbody fusion (ALIF), lateral or anterolateral approach lumbar interbody fusion (LLIF), posterior midline approach lumbar interbody fusion (PLIF), and transforaminal posterior lumbar interbody fusion (TLIF) to complete a series of procedures such as discectomy, bone grafting, and interbody fusion cage implantation. Among these, interbody fusion is particularly important for postoperative symptom recovery and spinal stability in lumbar spine patients.

[0003] Subsidence of the intervertebral fusion cage into the adjacent vertebral body can cause potential complications, such as loss of disc height, weakened intervertebral support, ligament laxity, reduced intervertebral foramen volume, and spinal instability. PLIF and TLIF are currently the most commonly used lumbar fusion procedures. The surgery requires access to the intervertebral space through a narrow window (Kambin's triangle) to perform discectomy, bone grafting, and cage implantation. Because the Kambin's triangle limits the use of larger fusion cages, it cannot adequately cover the endplates, increasing the risk of cage subsidence. Cage subsidence has been proven to be a risk factor for revision surgery. Currently, clinically available intervertebral fusion cages have relatively simple structures and uniform widths (mostly 10mm), resulting in less than ideal post-implantation stability and anti-subsidence properties. Summary of the Invention

[0004] To address the problems existing in the prior art, this utility model provides an expandable interbody fusion device with a reasonable structure that can increase stability and resistance to subsidence.

[0005] To achieve the above objectives, this utility model employs an expandable interbody fusion device, comprising an acetabular cup and a titanium cage, wherein the acetabular cup is hollow inside and the titanium cage is installed inside the acetabular cup;

[0006] The acetabular cup includes a symmetrically arranged left and right shells. Multiple vertically arranged columns are installed on the left and right shells respectively. An I-beam frame is installed at the front end of the left and right shells. The left and right shells can slide along the I-beam frame. A certain gap is provided in the middle and rear of the left and right shells. The upper and lower surfaces of the middle of the left and right shells are respectively provided with locking serrations. Flexible support columns and bridging columns for connecting the left and right shells are installed between the gaps of the left and right shells. The acetabular cup expands in the left and right direction through the I-beam frame, flexible support columns and bridging columns.

[0007] The front end of the titanium cage is conical, and a limiting groove that cooperates with the I-beam frame is provided inside the conical front end. The middle part of the titanium cage is provided with a bone graft cavity, and the upper and lower sides of the bone graft cavity are open. The cage wall of the titanium cage is provided with multiple hollow holes.

[0008] Preferably, the rear ends of the left and right housings are respectively provided with threaded holes.

[0009] Preferably, the locking serrations on the left and right housings are arranged symmetrically, and the locking direction of the locking serrations faces backward.

[0010] Preferably, the expansion range of the acetabular cup is 12mm to 20mm.

[0011] Preferably, both the left and right shells are made of polyetheretherketone (PEEK); the columns and I-beam frames are made of titanium alloy.

[0012] Preferably, the titanium cage has lugs on its left and right cage walls for locking the titanium cage inside the acetabular cup, and the rear end of the titanium cage has a titanium cage threaded hole.

[0013] Preferably, the acetabular cup has a smaller front end and a larger rear end, with the front top of the acetabular cup having a vertical planar structure and the rear end having a rectangular frame shape, and the corners of the acetabular cup surface having a rounded transition.

[0014] Preferably, the plurality of flexible struts are respectively installed between the upper and lower surfaces of the middle portion of the left and right shells, and the two bridging struts are respectively installed between the upper and lower surfaces of the rear ends of the left and right shells.

[0015] Preferably, the flexible support column and the bridging column are made of polyetheretherketone (PEEK).

[0016] Preferably, the rear ends of the left and right housings are provided with mutually cooperating limiting portions.

[0017] Compared with existing technologies, the expandable intervertebral fusion device of this invention has a compact structure, which minimizes damage to the dura mater and nerve roots during implantation. By expanding within the intervertebral space, it increases the contact area between the fusion device and the endplate, disperses the force over a larger area, and reduces the maximum pressure applied to adjacent endplates. Theoretically, this reduces the possibility of fusion device subsidence and maximizes the potential of the expandable fusion device, reducing displacement and improving installation stability. The acetabular cup and titanium cage assembly are available in various sizes to adapt to changes in the patient's anatomical structure, thereby achieving a more precise match between the implant and individualized anatomical features.

[0018] The interbody fusion device has a reasonable structure, which can increase stability and anti-settlement properties, thus providing certain assistance and guidance for clinical practice. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the expandable interbody fusion device of this utility model. Figure 1 (Before expansion);

[0020] Figure 2 This is a schematic diagram of the expandable interbody fusion device of this utility model. Figure 2 (After expansion);

[0021] In the diagram: 1. Right shell, 2. Left shell, 3. Column, 4. I-beam frame, 5. Positioning serration, 6. Flexible support column, 7. Bridging column, 8. Right threaded hole, 9. Left threaded hole, 10. Limiting part, 11. Titanium cage, 12. Bone graft cavity, 13. Limiting groove, 14. Hollow hole, 15. Lug, 16. Titanium cage threaded hole. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings.

[0023] In the description of this utility model, it should be understood that the terms "front", "rear", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used to facilitate the description of this utility model and to simplify 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 limiting the scope of protection of this utility model.

[0024] like Figure 1 , Figure 2 As shown, an expandable interbody fusion device includes an acetabular cup and a titanium cage 11, wherein the acetabular cup is hollow inside and the titanium cage 11 is installed inside the acetabular cup;

[0025] The acetabular cup includes a left shell 2 and a right shell 1 arranged symmetrically. Multiple vertical columns 3 are installed on the left and right shells respectively. In this embodiment, four columns are used. By setting four columns 3, a good load-bearing and support function can be achieved, which helps to ensure the stability of the main structure of the fusion device.

[0026] The front ends of the left and right shells are equipped with I-beam frames 4, and the left and right shells can slide along the I-beam frames 4. The I-beam frames 4 ensure that the left shell 2 and the right shell 1 can move left and right when the acetabular cup expands, and will not shift forward and backward.

[0027] The left and right shells have a certain gap in the middle and rear ends to facilitate the insertion of the titanium cage 11 into the acetabular cup from the rear end. The upper and lower surfaces of the middle of the left and right shells are respectively provided with locking serrations 5, which can better fit with the upper and lower vertebral endplates during implantation and match each other in terms of anatomical features. Flexible support columns 6 and bridging columns 7 are installed between the gaps of the left and right shells to connect the left shell 2 and the right shell 1. The acetabular cup can be expanded in the left and right directions through the I-frame 4, the flexible support column 6 and the bridging column 7.

[0028] The front end of the titanium cage 11 is tapered, which is conducive to the precise implantation of the titanium cage 11. The tapered front end of the titanium cage 11 is provided with a limiting groove 13 that cooperates with the I-frame 4, which makes it easy for the titanium cage 11 to be locked on the acetabular cup, providing structural stability for intervertebral fusion, which helps to ensure that it is not easy to fall off after implantation, and improves the fusion rate and the stability of the fusion device.

[0029] The titanium cage 11 has a bone graft cavity 12 in the middle. The upper and lower sides of the bone graft cavity 12 are open, which can significantly expand the contact area between the bone graft area and the upper and lower endplates, which is beneficial to improving the fusion rate. At the same time, it is also beneficial to increase the amount of bone graft and improve the fusion rate. The cage wall of the titanium cage 11 has multiple hollow holes 14. In this embodiment, multiple hollow holes 14 are provided on the left and right cage walls and the upper and lower cage walls. The hollow holes 14 increase the microscopic connectivity between the bone particles in the bone graft cavity 12 and the upper and lower endplates, thereby improving the survival rate of the bone graft.

[0030] As a preferred embodiment, such as Figure 1 As shown, the left housing 2 has a left threaded hole 9 at its rear end, and the right housing 1 has a right threaded hole 8 at its rear end. The left threaded hole 9 and the right threaded hole 8 are arranged symmetrically. The left threaded hole 9 and the right threaded hole 8 facilitate clamping of the left and right housings in various ways, improving the stability and operability of the expandable interbody fusion device during implantation.

[0031] As a preferred embodiment, such as Figure 1 As shown, the locking serrations 5 on the upper surface of the left and right shells are symmetrically arranged, and the locking serrations 5 on the lower surface are also symmetrically arranged. The locking direction of the locking serrations 5 is towards the rear. By increasing the friction through the locking serrations 5, the displacement during the implantation process can be effectively prevented.

[0032] In a preferred embodiment, the expansion range of the acetabular cup is 12mm to 20mm, which allows for the installation of titanium cages 11 of various sizes inside the acetabular cup, thus enabling multiple size options for the acetabular cup and titanium cage.

[0033] In a preferred embodiment, both the left shell 2 and the right shell 1 are made of polyetheretherketone (PEEK). PEEK's elastic modulus is close to that of bone, significantly reducing the risk of fusion cup subsidence. The uprights 3 and the I-beam frame 4 are made of titanium alloy, which has postoperative imaging characteristics, facilitating the visualization of instruments during and after surgery. The titanium cage 11 is also made of titanium alloy. Furthermore, the flexible support 6 and the bridging column 7 are also made of PEEK, integrally formed between the left shell 2 and the right shell 1, making the acetabular cup a single, integrated structure.

[0034] As a preferred embodiment, such as Figure 1 As shown, the titanium cage 11 has lugs 15 on its left and right cage walls. When the titanium cage 11 is fully inserted into the acetabular cup, the lugs 15 can be locked inside the acetabular cup to prevent the titanium cage 11 from moving forward or backward after implantation, thus improving the structural stability of intervertebral fusion. The titanium cage 11 has a titanium cage threaded hole 16 at its rear end, which facilitates clamping the titanium cage 11 in various ways.

[0035] As a preferred embodiment, the acetabular cup has a flexible periphery, which allows the implant (interbody fusion device) to conform to the contour of the surrounding endplate, preventing endplate damage, subsidence and implant displacement. The anterior tip of the acetabular cup has a vertical planar structure, with a small front end and a large rear end, and the edges are rounded, which makes it easier to implant the fusion device into the target position, greatly improving the implantation efficiency and operation accuracy, and making it less likely to damage the surrounding vertebral body, nerves and soft tissues.

[0036] As a preferred embodiment, such as Figure 1 , Figure 2 As shown, multiple flexible struts 6 are respectively installed between the upper and lower surfaces of the left and right shells. The flexible struts 6 not only maintain the stability of the structure during expansion, but also help prevent bone fragments from falling off during implantation of the titanium cage 11. Two bridging struts 7 are symmetrically arranged, one installed between the upper surfaces of the rear ends of the left and right shells, and the other installed between the lower surfaces of the rear ends. After expansion, when the titanium cage 11 is installed in the acetabular cup, the bridging struts 7 can ensure the connection stability between the left and right shells.

[0037] As a preferred embodiment, such as Figure 1 , Figure 2As shown, the rear ends of the left shell 2 and the right shell 1 are provided with mutually cooperating limiting parts 10. The limiting parts 10 ensure that the gap on the acetabular cup can meet the implantation requirements of the titanium cage 11, avoiding the situation where the gap on the acetabular cup is too small, making it impossible to install the titanium cage 11. In addition, the small outline of the acetabular cup and the titanium cage 11 can minimize the surgical channel required for the placement of the intervertebral fusion device, while achieving substantial intra-intervertebral space expansion by implanting the titanium cage 11.

[0038] The use of this expandable interbody fusion device, taking posterior lumbar T / PLIF surgery as an example:

[0039] First, the left threaded hole 9 and the right threaded hole 8 are fixed and clamped using the existing external guide adjuster. The acetabular cup is slowly implanted into the intervertebral space through the Kambin triangle. Then, the adjuster fixing the right threaded hole 8 is removed. The acetabular cup is implanted into the appropriate area using the adjuster. At this time, the adjuster fixing the left threaded hole 9 acts as an external guide. The titanium cage threaded hole 16 of the titanium cage 11 is fixed using the existing limiting adjuster (at this time, the bone graft cavity 12 of the titanium cage 11 has been pre-filled with bone particles). Following the external guide, the titanium cage 11 is accurately implanted into the acetabular cup, achieving a perfect combination of implantation and expansion. Finally, the titanium cage 11 is locked in the shell of the acetabular cup.

[0040] This invention increases the contact area between the fusion device and the endplate by expanding within the intervertebral space, distributing the force over a larger area and reducing the maximum pressure applied to adjacent endplates. Theoretically, this reduces the rate of fusion device subsidence and provides a more stable environment for bone fusion.

[0041] The above descriptions are merely embodiments of this utility model, and common technical solutions and / or characteristics known in the scheme are not described in detail here. It should be noted that those skilled in the art can make various modifications, improvements, or equivalent substitutions without departing from the technical solution of this utility model, and all such modifications, improvements, or equivalent substitutions should be covered within the scope of the claims of this utility model. The scope of protection claimed in this application should be determined by the content of its claims, and the detailed descriptions of the embodiments can be used to interpret the content of the claims.

Claims

1. An expandable intervertebral cage, comprising an acetabular cup and a titanium cage (11), the acetabular cup being hollow inside, the titanium cage (11) being installed in the inside of the acetabular cup, characterized in that: the acetabular cup comprises a left shell (2) and a right shell (1) arranged symmetrically, a plurality of columns (3) arranged in up and down direction are respectively installed on the left and right shells, an I-shaped frame (4) is installed on the front end of the left and right shells, the left and right shells can slide along the I-shaped frame (4), a gap is provided in the middle and rear end of the left and right shells, a clamping sawtooth (5) is respectively arranged on the upper and lower surfaces of the middle of the left and right shells, a flexible support (6) and a bridging column (7) for connecting the left shell (2) and the right shell (1) are installed between the gaps of the left and right shells, and the acetabular cup is expanded in the left-right direction through the I-shaped frame (4), the flexible support (6) and the bridging column (7); the front end of the titanium cage (11) is conical, a limiting groove (13) matched with the I-shaped frame (4) is arranged in the conical front end, a bone graft cavity (12) is arranged in the middle of the titanium cage (11), the upper and lower sides of the bone graft cavity (12) are open, and a plurality of hollow holes (14) are arranged on the cage wall of the titanium cage (11). threaded holes are respectively arranged in the rear ends of the left and right shells.

2. The expandable intervertebral fusion cage of claim 1, wherein: The clamping sawtooth (5) on the left and right shells is arranged symmetrically, and the clamping direction of the clamping sawtooth (5) is towards the rear.

3. The expandable intervertebral fusion cage of claim 1, wherein: The expansion range of the acetabular cup is 12mm-20mm.

4. The expandable intervertebral fusion cage of claim 1, wherein: The left shell (2) and the right shell (1) are made of polyether ether ketone material; the columns (3) and the I-shaped frame (4) are made of titanium alloy material.

5. The expandable intervertebral fusion cage of claim 1, wherein: The left and right cage walls of the titanium cage (11) are provided with lugs (15) for locking the titanium cage (11) inside the acetabular cup, and a titanium cage threaded hole (16) is arranged at the rear end of the titanium cage (11).

6. The expandable intervertebral fusion cage of claim 1, wherein: The front end of the acetabular cup is small and the rear end is large, the front top end of the acetabular cup is a vertical plane structure, the rear end is a rectangular frame, and the surface corners of the acetabular cup adopt a circular arc transition.

7. The expandable intervertebral fusion cage of claim 1, wherein: A plurality of flexible supports (6) are respectively installed between the upper surfaces and the lower surfaces of the middle of the left and right shells, and two bridging columns (7) are respectively installed between the upper surfaces and the lower surfaces of the rear ends of the left and right shells.

8. The expandable intervertebral fusion cage of claim 1, wherein: The flexible support (6) and the bridging column (7) are respectively made of polyether ether ketone material.

9. The expandable intervertebral fusion cage of Claims 1 or 8, wherein: The rear ends of the left shell (2) and the right shell (1) are provided with limiting parts (10) matched with each other.

10. The expandable intervertebral fusion cage of claim 1, wherein: ​

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