Intervertebral fusion cage with adjustable length and height in both directions
The interbody fusion device, with its sliding guide plate and wedge-shaped threaded transmission structure, solves the problems of no bone replantation and large size in existing technologies, thus promoting bone recovery and reducing damage.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ZHENGZHOU JIEZHENG IND CO LTD
- Filing Date
- 2025-03-19
- Publication Date
- 2026-06-19
AI Technical Summary
Existing interbody fusion devices cannot achieve bone replantation after implantation and height adjustment, limiting bone growth during the recovery process. They also have problems such as large size and easy damage to adjacent tissues during implantation.
The upper and lower support plates are designed with sliding guides, and the length and height can be adjusted in both directions through the wedge structure of the guide head and the holding head and the threaded transmission structure. This avoids the use of an external frame, provides a hollow cavity for bone grafting, and reduces resistance and damage during the implantation process.
It enables bone replantation after implantation, promotes bone recovery, reduces damage during the implantation process, and has a smaller size than traditional fusion devices, which is beneficial for the healing of the affected area.
Smart Images
Figure CN224370039U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to an interbody fusion device, and more particularly to an interbody fusion device with bidirectional adjustable length and height, which belongs to the category of medical devices. Background Technology
[0002] Currently, most conventional thoracolumbar fusion devices are one-piece designs with anti-slip structures on both the upper and lower surfaces. The hollow part has a cavity for filling with bone or artificial bone. During the implantation process, the implant channel needs to be enlarged by cutting bone tissue through methods such as drilling, sawing, and biting. The channel needs to be larger than the cross-section of the fusion device itself. Finally, the fusion device is violently struck into the working area with tools such as fusion device holding instruments and bone hammers. The implantation process is accompanied by huge resistance and impact force. The resistance during the operation is high, and it is easy to damage adjacent tissues.
[0003] To address this, some companies have designed and developed height-adjustable fusion devices. These devices use an outer frame to restrain upper and lower support plates, and the height is adjusted using a holder before insertion into the working area. For example, Chinese Patent Application No. 202111496485.4 discloses a fusion device with adjustable post-graft height. However, this type of fusion device cannot achieve bone replantation after implantation and height adjustment. While the height is adjusted to the desired level using an adjustment device, bone grafting must be performed through grafting windows on the upper and lower surfaces of the fusion device due to the outer frame. This prevents bone replantation after implantation and height adjustment, limiting bone growth during the recovery process. Furthermore, the outer frame restricts the length of the fusion device, making it difficult for bone to fill the internal cavity after implantation, which is detrimental to healing at the affected site. Additionally, the presence of the outer frame results in a larger product size. Utility Model Content
[0004] The purpose of this invention is to provide an interbody fusion device with bidirectional adjustable length and height to solve the problem in the prior art that it is impossible to achieve bone replantation after implantation and height adjustment, thus limiting bone growth during the recovery process.
[0005] To solve the above problems, the height-adjustable interbody fusion device involved in this utility model adopts the following technical solution: an interbody fusion device with bidirectional adjustable length and height, including an upper support plate and a lower support plate that slide and guide each other vertically. The upper and lower support plates have a hollow cavity that runs vertically through the center. A guide head and a holding head are respectively provided at the front and rear ends of the upper and lower support plates. Both the guide head and the holding head are wedge-shaped, with their top ends facing each other. The two wedge surfaces of the guide head and the holding head slide and contact the inclined surfaces of the upper and lower support plates respectively. The guide head and the holding head are driven to separate and converge through a threaded transmission structure. The threaded transmission structure includes a threaded screw and a nut. The nut is configured to prevent rotation and movement of the guide head. The screw is configured to prevent rotation and movement of the holding head. The end of the screw has an exposed screwing structure. There is a gap between the upper and lower support plates that connects to the hollow cavity after the guide head and the holding head converge and open the upper and lower support plates.
[0006] The guide head and gripping head are slidably assembled with the upper support plate and the lower support plate through the cooperation of dovetail grooves and trapezoidal blocks, and the two wedge surfaces of the guide head and gripping head are in contact with the inclined surfaces of the upper support plate and the lower support plate.
[0007] The upper support plate and the lower support plate are slidably assembled by mutually cooperating slide bars and slide grooves.
[0008] The upper support plate and the lower support plate have the same structure. The slide bar of the upper support plate extends downward from the middle part and is assembled with the slide groove of the lower support plate. The slide bar of the lower support plate extends upward from the middle part and is assembled with the slide groove of the upper support plate.
[0009] The nut and screw components are designed to prevent detachment.
[0010] The nut is integrally formed with the guide head, and the thread of the nut is screwed onto the wall of the through hole in the guide head.
[0011] The guide head has a stepped hole with an internal thread. The internal thread is located in the small diameter section of the stepped hole. The screw is engaged with the stepped surface of the stepped hole through a large diameter collar at the end and with an anti-disengagement nut.
[0012] A limiting sleeve is fixedly sleeved on the screw component, and the corresponding end of the limiting sleeve is matched with the guide head for limiting.
[0013] The screw component is engaged with the handle head to prevent displacement through the end cap and the limiting sleeve, and the screwing structure is a hexagonal countersunk hole recessed on the end cap.
[0014] One end of the gripping head presses against the nut of the screw, and the other end presses against the limiting sleeve through the friction ring.
[0015] The upper and lower support plates of this invention achieve lifting and lowering by bringing together and separating the holding head and the guide head. It does not require an outer frame, has a small size, and the end of the bolt used as the drive has an exposed screwing structure, which can be lifted and lowered after implantation. Furthermore, after being raised, there is a gap between the upper and lower support plates that communicates with the hollow cavity, which allows the bone to be implanted from the side after the height is adjusted, which is beneficial to the healing of the affected area. Attached Figure Description
[0016] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the embodiments will be briefly described below:
[0017] Figure 1 This is a schematic diagram of the structure of an embodiment of the present utility model;
[0018] Figure 2 for Figure 1 Right view;
[0019] Figure 3 for Figure 2 AA section view;
[0020] Figure 4 This is a three-dimensional structural diagram of the lowest initial height of this utility model embodiment;
[0021] Figure 5 This is a three-dimensional structural diagram of the maximum unfolded height of this utility model embodiment;
[0022] Figure 6 for Figure 1 A three-dimensional structural diagram of the upper or lower support plate in one direction;
[0023] Figure 7 for Figure 1 A three-dimensional structural diagram of the upper or lower support plate in another direction;
[0024] Figure 8 for Figure 1 A three-dimensional structural diagram of the guide head;
[0025] Figure 9 for Figure 1 A three-dimensional structural diagram of the central grip head.
[0026] Figure 10 for Figure 3 A schematic diagram of the structure of the screw rod.
[0027] Figure 11 for Figure 3 A schematic diagram of the assembly of the gripping head, screw, and friction ring. Detailed Implementation
[0028] To make the technical objectives, technical solutions, and beneficial effects of this utility model clearer, the technical solution of this utility model will be further described below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model; that is, 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.
[0029] Specific embodiments of the height-adjustable interbody fusion device involved in this utility model are as follows: Figures 1-9In this assembly, the upper support plate 1 and the lower support plate 2 have identical structures. The lower support plate 2 rotates 180 degrees and is fastened to the upper support plate 1. The upper surface of the upper support plate 1 has an anti-slip structure, and the lower surface of the lower support plate 2 also has an anti-slip structure. There is a hollow cavity 3 running vertically through the center of the upper support plate 1 and the lower support plate 2. In other words, there is a large hole in the middle of the upper and lower support plates. When assembled, the whole assembly forms a hollow cavity 3. The upper support plate 1 and the lower support plate 2 are slidably guided together. The upper support plate 1 and the lower support plate 2 are slidably assembled by mutually cooperating slide bars 4 and slide grooves 5. The middle part of one side of the upper support plate 1 is provided with a downwardly extending slide bar 4, and the other side is provided with a slide groove 5. The slide bar 4 of the upper support plate is slidably assembled with the slide groove of the lower support plate 2. Similarly, the middle part of one side of the lower support plate 2 is provided with an upwardly extending slide bar 4, and the other side is provided with a slide groove 5. The slide bar 4 of the lower support plate 2 is slidably assembled with the slide groove 5 of the upper support plate 1. Guide heads 8 and gripping heads 9 are respectively provided at the front and rear ends of the upper support plate 1 and the lower support plate 2. Both guide heads 8 and gripping heads 9 are wedge-shaped, and the top ends of guide heads 8 and gripping heads 9 are opposite each other. The two wedge surfaces of guide heads 8 and gripping heads 9 slide in contact with the inclined surfaces of the upper support plate 1 and the lower support plate 2 respectively. In this way, when guide heads 8 and gripping heads 9 are brought together, they will open the upper and lower support plates. The contact engagement is achieved as follows: a first dovetail groove 10 is provided on the lower part of one side of the guide head 8, and a second dovetail groove 11 is provided on the upper part of the other side. A first trapezoidal block 12 protrudes from the inclined surface of the upper and lower support plates. The first dovetail groove 10 engages with the first trapezoidal block 12 of the lower support plate 2, and the second dovetail groove 11 engages with the first trapezoidal block 12 of the upper support plate 1, thus ensuring that the surfaces cannot be separated and remain in contact. Similarly, a second trapezoidal block 13 is provided in the middle of the two wedge surfaces of the gripping head 9, and a third dovetail groove 14 is provided at the corresponding position of the upper and lower support plates. The two second trapezoidal blocks 13 of the gripping head engage with the third dovetail grooves 14 of the upper and lower support plates, thus ensuring that the surfaces cannot be separated and remain in contact. The guide head 8 and the gripping head 9 are driven to separate and converge through a threaded transmission structure. In this way, the upper and lower support plates will separate horizontally, achieving height adjustment. During use, the shape of the skeleton will not be altered. Furthermore, during installation, the upper and lower support plates can be in a converged state, making them easy to install within the skeleton without requiring excessive pressure, minimizing damage. After installation, the upper and lower support plates can be separated. Adjustment in the length direction is also achieved by the convergence and separation of the guide head 8 and the holding head 9. After the guide head 8 and the holding head 9 are converged, the length of the entire device decreases, providing extra space for bone grafting, facilitating bone recovery. The smaller size itself also promotes bone recovery and growth. The threaded transmission structure here includes a threaded screw 15 and a nut.The nut is integrally formed with the guide head 8. The thread of the nut is opened on the wall of the through hole opened on the guide head 8. The through hole with internal thread in the guide head is a stepped hole 16. The internal thread is set in the small diameter section of the stepped hole 16. The screw 15 is engaged with the stepped surface of the stepped hole 16 through the large diameter collar 17 at the end to prevent it from disengaging from the nut, that is, to prevent it from disengaging from the guide head. The screw 15 is fitted with the gripping head 9 to prevent rotational displacement. The assembly is achieved as follows: the screw 15 passes through a through hole in the gripping head 9. A limiting sleeve 18 is fixedly fitted onto the screw 15. An arc-shaped groove is formed on the circumferential surface of the screw 15. Six deformation points are provided on the peripheral wall of the limiting sleeve 18 corresponding to the arc-shaped groove of the screw 15, thus achieving assembly. A friction ring 6 is also fitted onto the screw 15. One end of the friction ring 6 presses against the limiting sleeve 18, and the other end presses against the gripping head 9. The gripping head 9 presses against the nut 7 on the end of the screw 15, thus achieving a rotational displacement prevention fit between the screw 15 and the gripping head 9. A concave-convex structure 20 is provided on the end face where the nut 7 mates with the gripping head to increase friction and prevent thread loosening. Simultaneously, the corresponding end of the limiting sleeve 18 engages with the guide head to prevent the guide head from getting too close to the gripping head. The screw cap 7 of the screw component has a recessed hexagonal countersunk hole 19, which is a screw-tightening structure and is exposed on the outside.
[0030] After the guide head and the holding head come together to open the upper support plate and the lower support plate, the upper support plate 1 and the lower support plate 2 move away from each other vertically, and there is a gap between them that communicates with the hollow cavity 3 of both of them. Bone grafting can be performed through this gap.
[0031] In the above embodiments, the screw component is engaged with the gripping head to prevent displacement through the end cap, the limiting sleeve, and the friction ring. In other embodiments, other structures can also be used for the anti-displacement engagement.
[0032] In the above embodiments, the nut component achieves anti-displacement and anti-rotation cooperation between the two by being integrally set with the guide head. In other embodiments, it can also be achieved by having other assembly structures.
[0033] The knob structure in the above embodiment is a recessed hexagonal countersunk hole on the nail head. In other embodiments, it can also be a screw structure of other forms, such as a flathead or a crosshead.
[0034] In the above embodiments, the guide head and the gripping head are slidably assembled with the upper support plate and the lower support plate through the cooperation of the dovetail groove and the trapezoidal block, and the two wedge surfaces of the guide head and the gripping head are in contact with the inclined surfaces of the upper support plate and the lower support plate. In other embodiments, the contact between the wedge surfaces and the inclined surfaces can also be maintained by other limiting structures, such as: a tension spring is provided between the upper and lower support plates.
[0035] In the above embodiment, one end of the gripping head presses against the nut of the screw, and the other end presses against the limiting sleeve through the friction ring. In other embodiments, the gripping head can also press directly against the limiting sleeve.
[0036] Finally, it should be noted that the above embodiments are only for illustration and not for limiting the technical solutions of this utility model. Any equivalent substitutions and modifications or partial substitutions that do not depart from the spirit and scope of this utility model should be covered within the scope of protection of the claims of this utility model.
Claims
1. A bidirectional adjustable interbody fusion device, comprising an upper support plate and a lower support plate that slide and guide vertically, wherein the upper and lower support plates have a hollow cavity extending vertically through their centers, characterized in that, The upper and lower support plates are respectively provided with guide heads and gripping heads at their front and rear ends. Both guide heads and gripping heads are wedge-shaped, with their top ends facing each other. The two wedge surfaces of the guide heads and gripping heads slide in contact with the inclined surfaces of the upper and lower support plates, respectively. The guide heads and gripping heads are driven to separate and converge through a threaded transmission structure. The threaded transmission structure includes a threaded screw and a nut. The nut is designed to prevent rotation and movement of the guide head, and the screw is designed to prevent rotation and movement of the gripping head. The end of the screw has an exposed screwing structure. There is a gap between the upper and lower support plates that connects to the hollow cavity after the guide heads and gripping heads converge and spread the upper and lower support plates apart.
2. The bidirectional adjustable length and height interbody fusion device according to claim 1, characterized in that, The guide head and gripping head are slidably assembled with the upper support plate and the lower support plate through the cooperation of dovetail grooves and trapezoidal blocks, and the two wedge surfaces of the guide head and gripping head are in contact with the inclined surfaces of the upper support plate and the lower support plate.
3. The bidirectional adjustable length and height interbody fusion device according to claim 2, characterized in that, The upper support plate and the lower support plate are slidably assembled by mutually cooperating slide bars and slide grooves.
4. The bidirectional adjustable length and height interbody fusion device according to claim 3, characterized in that, The upper support plate and the lower support plate have the same structure. The slide bar of the upper support plate extends downward from the middle part and is assembled with the slide groove of the lower support plate. The slide bar of the lower support plate extends upward from the middle part and is assembled with the slide groove of the upper support plate.
5. The bidirectional adjustable length and height interbody fusion device according to any one of claims 1-4, characterized in that, The nut and screw components are designed to prevent detachment.
6. The bidirectional adjustable length and height interbody fusion device according to claim 5, characterized in that, The nut is integrally formed with the guide head, and the thread of the nut is screwed onto the wall of the through hole in the guide head.
7. The bidirectional adjustable length and height interbody fusion device according to claim 6, characterized in that, The guide head has a stepped hole with an internal thread. The internal thread is located in the small diameter section of the stepped hole. The screw is engaged with the stepped surface of the stepped hole through a large diameter collar at the end and with an anti-disengagement nut.
8. The bidirectional adjustable length and height interbody fusion device according to claim 7, characterized in that, A limiting sleeve is fixedly sleeved on the screw component, and the corresponding end of the limiting sleeve is matched with the guide head for limiting.
9. The bidirectional adjustable interbody fusion device according to claim 8, characterized in that, The screw component is engaged with the handle head to prevent displacement through the end cap and the limiting sleeve, and the screwing structure is a hexagonal countersunk hole recessed on the end cap.
10. The bidirectional adjustable interbody fusion device according to claim 9, characterized in that, One end of the gripping head presses against the nut of the screw, and the other end presses against the limiting sleeve through the friction ring.