Fusion cage for posterior lumbar fusion

Abstract

The utility model discloses a fusion cage for lumbar posterior fusion, which relates to the technical field of livestock breeding equipment and is technically characterized by comprising a fusion cage main body, and the fusion cage main body is of an upper arc-shaped double-arch structure and a lower arc-shaped double-arch structure. The fusion cage body is provided with a front end, a rear end, an upper surface, a lower surface, a left side face and a right side face, the front end of the fusion cage body is of a wedge-shaped structure, side holes are formed in the left side face and the right side face of the fusion cage body respectively, and textured tooth-shaped structures are arranged on the upper surface and the lower surface of the fusion cage. The upper arc and the lower arc of the lumbar fusion cage body are attached to a lumbar end plate, the front end ellipse facilitates oblique implantation, and the lumbar fusion cage is low in left and high in right and can rotate and stably support. The surface tooth-shaped textures increase friction, and the right-side forward-to-left reverse structure enhances stability. Biocompatible PEEK is adopted, and a developing needle is arranged to assist in monitoring. The minimally invasive concept is adopted, single-side small incision oblique planting rotation is adopted, injuries are reduced, the intervertebral height and spine stability are maintained, bone fusion is promoted, the operation effect is good, trauma is small, recovery is fast, and the clinical application potential is large.

Description

Technical Field

[0001] This utility model relates to the field of medical devices, specifically to a lumbar fusion device for posterior lumbar fusion surgery. Background Technology

[0002] In recent years, with the development of minimally invasive spinal surgery, lumbar interbody fusion surgery has gradually become an effective means of treating lumbar degenerative diseases (such as intervertebral disc herniation, spinal stenosis, and lumbar instability). Posterior lumbar fusion surgery is a major surgical approach for treating degenerative lumbar spine diseases. It primarily includes posterior lumbar interbody fusion and transforaminal lumbar interbody fusion. These two techniques form the technical basis of minimally invasive posterior lumbar fusion. With the development of spinal endoscopic techniques, such as UBE (unilateral dual-channel endoscopic technique) and AUSS (arthroscopic-assisted single-port spinal surgery technique), various surgical methods have been developed, including minimally invasive transforaminal interbody fusion, unilateral dual-channel endoscopic transforaminal lumbar fusion, and unilateral dual-channel endoscopic extraforaminal lumbar fusion. Benefiting from the advancements in endoscopic technology, due to its wide field of vision and thorough treatment of the intervertebral space, current minimally invasive spinal surgery can achieve single-segment minimally invasive lumbar fusion through the implantation of a single large fusion cage placed transversely and minimally invasive unilateral fixation. This allows for minimally invasive fusion of a single lumbar segment through a single incision, without damaging the muscles on the healthy side of the lumbar spine. It also saves surgical time, reduces intraoperative bleeding, and increases the fusion rate.

[0003] During the procedure, the selection and implantation of the fusion cage are crucial steps. As a core implant supporting the intervertebral space and promoting bone fusion, the fusion cage plays a vital role in restoring intervertebral height, maintaining spinal stability, and reducing nerve root compression. However, existing fusion cages still have certain limitations in terms of shape, size, materials, and implantation methods. For example, traditional fusion cages are mostly symmetrically designed, which cannot fully adapt to the physiological curvature of the intervertebral space; their implantation often relies on multiple incisions and bilateral fixation, which not only increases surgical trauma but may also damage surrounding soft tissues, affecting postoperative recovery and bone fusion outcomes; their size is relatively small, resulting in a relatively low contact area between the fusion cage and the endplate postoperatively, which can lead to increased pressure on the endplate and uneven distribution of intervertebral pressure, thus easily weakening the stability of the fusion cage.

[0004] Therefore, an ideal lumbar fusion cage should have a double-arched curved surface design to fully match the morphology of the vertebral endplate, and sufficient length to increase the contact area between the fusion cage and the endplate, reducing the possibility of cage subsidence. Simultaneously, the fusion cage needs to be rotated horizontally after oblique implantation to achieve a stable support effect. Furthermore, the surface of the fusion cage should have a textured serrated structure to promote bone fusion with the endplate and prevent displacement and subsidence. The fusion cage material should possess good biocompatibility and sufficient strength, providing appropriate elasticity to promote bone healing while maintaining implant stability. To meet the needs of intraoperative positioning and postoperative monitoring, the fusion cage can be designed with a contrast needle for easy fluoroscopic observation of its implantation position. Therefore, there is an urgent need for a large-size lumbar fusion cage based on the concept of minimally invasive posterior lumbar fusion surgery to provide better biomechanical performance and bone fusion effect, while meeting the requirements of minimally invasive surgery for small incisions, low trauma, and rapid recovery. This type of fusion cage will significantly improve the clinical outcomes of lumbar fusion surgery, reduce postoperative complications, and accelerate patient recovery. Utility Model Content

[0005] To address the shortcomings of existing technologies, this utility model provides a fusion device for posterior lumbar fusion surgery, which solves the limitations of existing fusion devices in terms of shape, size, materials, and implantation methods.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a fusion device for posterior lumbar fusion surgery, comprising a fusion device body, the fusion device body being "E"-shaped and having a double-arch structure with upper and lower arcs, the upper surface and lower surface of the fusion device being arc-shaped, the middle part of the fusion device body being hollowed out, the left and right sides of the fusion device body being respectively provided with bone filling holes, and the left and right sides of the rear end of the fusion device body being provided with clamping grooves.

[0007] Preferably, the upper and lower surfaces of the fusion device body are provided with textured tooth-like structures to increase the contact area with bone tissue and reduce the risk of fusion device displacement and settling.

[0008] Preferably, the upper and lower surfaces of the fusion device body are provided with toothed structures, wherein the upper and lower surfaces of the right side adopt a forward structure to optimize the implantation effect and effectively limit the backward displacement of the fusion device during the implantation process, and the left side adopts a reverse structure to prevent the fusion device from shifting forward after implantation. The opposing forces of the two surfaces make the fusion device more stable.

[0009] Preferably, the front end of the fusion device body is an elliptical structure to facilitate oblique implantation of the fusion device body into the intervertebral space.

[0010] Preferably, the upper and lower surfaces of the fusion body are non-parallel surfaces with an included angle α, and the fusion body is wedge-shaped with the left side lower than the right side.

[0011] Preferably, the fusion device body has a side hole on each of its left and right sides, and the side hole is located in the middle of the left and right sides.

[0012] Preferably, the fusion device body is made of biocompatible PEEK material to provide sufficient strength and stability and to be compatible with the surrounding bone tissue.

[0013] Preferably, the fusion unit body is provided with two developing needles, which are metal structures visible under fluoroscopy, located at the center of the front end and the right side of the rear end of the fusion unit body.

[0014] Preferably, after implantation, the fusion device body can be adjusted to a transverse position by oblique insertion and rotation to increase the contact area with the vertebral endplate and maintain the intervertebral height and the stability of the fusion device.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. This utility model discloses a lumbar fusion device for posterior lumbar fusion surgery. The main body of the fusion device is "E"-shaped, with an arched design featuring upper and lower arcs. The upper and lower surfaces are arc-shaped, conforming to the anatomical curvature of the lumbar endplate, ensuring stable contact with the endplate after implantation, increasing the contact area between the fusion device and bone tissue, and reducing the risk of device subsidence. The front end of the fusion device has an elliptical structure, facilitating oblique implantation into the intervertebral space. The main body of the fusion device is wedge-shaped, lower on the left and higher on the right, and can be rotated to a transverse position after implantation, achieving stable support for the intervertebral space.

[0017] 2. To promote bone fusion, the fusion device has a serrated surface to increase friction with the endplate, ensuring stable positioning after implantation and aiding in bone healing. Furthermore, the right side of the fusion device features a unidirectional structure on both upper and lower surfaces to optimize implantation and limit posterior displacement during the implantation process; while the left side is designed with a reverse structure to further enhance stability and limit anterior displacement after transverse placement.

[0018] 3. The fusion cage is made of biocompatible PEEK, ensuring excellent fatigue resistance while bearing the physiological load of the lumbar spine and compatibility with surrounding bone tissue. For precise intraoperative positioning and postoperative imaging monitoring, the fusion cage is equipped with a contrast-enhancing needle made of high-density metal, which can be visualized on X-ray or CT scans, assisting the surgeon in observing the implantation location and fusion status. The implantation method of this fusion cage combines the concept of minimally invasive posterior lumbar fusion surgery. It enters the intervertebral space through a small unilateral incision along the intermuscular space, inserts the fusion cage obliquely, and then rotates it transversely, effectively reducing damage to surrounding soft tissues and nerve roots, alleviating postoperative pain, reducing the risk of bleeding, and shortening recovery time. The unilateral fixation combined with the transverse implantation design of the fusion cage better maintains intervertebral height and spinal stability, promotes intervertebral bone fusion, and improves clinical surgical outcomes. This design fully demonstrates the advantages of minimally invasive surgery, featuring minimal trauma, rapid recovery, and good fusion results, and has broad clinical application potential. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of this utility model;

[0020] Figure 2 This is a schematic diagram of the side groove and developing needle structure of this utility model.

[0021] In the picture:

[0022] 100. Fusion unit body; 110. Upper surface of fusion unit; 120. Side hole; 130. Lower surface of fusion unit; 133. Right side face; 134. Left side face; 135. Bone graft cavity; 140. Lateral groove; 150. Front end of fusion unit body; 160. Rear end of fusion unit body; 162. Imaging needle; 170. Semicircle; 180. Narrow-faceted cuboid. Detailed Implementation

[0023] To further illustrate the various embodiments, the present invention provides accompanying drawings. These drawings are part of the disclosure of the present invention, mainly used to illustrate the embodiments, and can be used in conjunction with the relevant description in the specification to explain the operating principle of the embodiments. The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments. The present invention provides a fusion device for posterior lumbar fusion surgery, including a fusion device body 100, which is generally rectangular in shape, having a front end 150, a rear end 160, an upper surface 110, a lower surface 130, a left side 134, and a right side 133. A bone graft cavity 135 is hollowed out in the middle of the fusion device body 100 to fill the grafted bone to promote fusion.

[0024] The front end 150 of the fusion device is an elliptical structure with an arc design, which makes it easier to enter along the intervertebral foramen when implanted into the intervertebral space, facilitates rotational adjustment after initial implantation, and ensures the lateral stability of the fusion device.

[0025] The rear end 160 of the fusion device body is provided with a clamping structure that matches the fusion device inserter. In this embodiment, the clamping structure includes an insertion hole 154 located in the middle of the end face of the rear end 160 of the fusion device body and side grooves 140 located on both sides of the rear end of the fusion device body, so as to facilitate the clamping and insertion of the lumbar fusion device.

[0026] The main body 100 of the fusion device is designed as an "E" shape with a double-arched structure that is both upper and lower curved. The upper surface 110 and the lower surface 130 of the fusion device are both curved structures, matching the physiological curvature of the vertebral endplate. The curved design increases the contact area between the fusion device and the vertebral endplate, which helps to disperse intervertebral pressure, reduce implant settlement, and ensure postoperative stability of intervertebral height.

[0027] The fusion unit has a semicircular body on the right side (170°) and a narrow rectangular prism on the left side (180°), which allows it to better fit the endplate and conform to the anatomical structure.

[0028] The fusion device has a side hole 120 on each of its left and right sides. The side holes are located in the center of the left and right sides. The purpose of the side holes is to facilitate the growth of bone grafts inside and outside the fusion device together and to help fill the bone grafts.

[0029] A contrast needle 162 is provided in the middle of the front end 150 of the fusion device body, and a contrast needle 162 is provided on the upper right side of the rear end 160 of the fusion device body. All contrast needles 162 penetrate from the upper surface to the lower surface of the fusion device body 100, and are used to determine the implantation position of the fusion device body under intraoperative and postoperative fluoroscopy.

[0030] In practical use, the working principle of this utility model is as follows:

[0031] Under general anesthesia, in the prone position, and after fluoroscopic localization, a 3cm unilateral incision was made approximately 1cm lateral to the line connecting the L4 and L5 pedicles on the affected side. The skin, subcutaneous tissue, and lumbar fascia were incised, and an arthroscopic system was inserted. Blunt dissection was performed along the intermuscular spaces of the multifidus and longissimus muscles until the inferior articular process of L4 and the superior articular process of L5 were exposed. An ultrasonic osteotome was then used to remove the right inferior articular process of L4, part of the L4 laminae, and the superior articular process of L5. The ligamentum flavum was removed en bloc with a nucleus pulposus forceps to expose the dural sac and L5 nerve root. An assistant used a nerve retractor to retract the L5 nerve root towards the midline, exposing the L4-L5 intervertebral disc. The annulus fibrosus was incised, the intervertebral space was cleaned, and a fusion cage of appropriate size was selected after trial molding and measurement. The hollow structure of the fusion cage body was filled with autologous decompression bone particles, and the fusion cage was inserted at a 45° angle to approximately 5mm from the posterior edge of the vertebral body. A special tool was used to place the fusion cage transversely in the intervertebral space. C-arm fluoroscopy confirmed that the fusion device was in the right position and stable. The L5 nerve root was explored and found to be free of compression. The surgical incision was sutured layer by layer and bandaged.

[0032] The above are merely specific embodiments of this utility model, but the technical features of this utility model are not limited thereto. Any simple changes, equivalent substitutions, or modifications made based on this utility model to solve essentially the same technical problems and achieve essentially the same technical effects are all covered within the protection scope of this utility model.

Claims

1. A cage for posterior lumbar fusion, comprising a cage body, characterized in that: The fusion device body is "E" shaped and has a double-arch structure with upper and lower arcs. The upper and lower surfaces of the fusion device are arc-shaped. The middle of the fusion device body is hollowed out. Bone filling holes are provided on the left and right sides of the fusion device body. Clamping grooves are provided on the left and right sides of the rear end of the fusion device body.

2. The cage for posterior lumbar fusion surgery according to claim 1, wherein: The upper and lower surfaces of the fusion device are provided with textured tooth-like structures to increase the contact area with bone tissue and reduce the risk of displacement and settling of the fusion device.

3. The cage for posterior lumbar fusion surgery according to claim 2, wherein: The upper and lower surfaces of the fusion device are provided with toothed structures. The upper and lower surfaces of the right side adopt a forward structure to optimize the implantation effect and effectively limit the backward displacement of the fusion device during the implantation process. The left side adopts a reverse structure to prevent the fusion device from shifting forward after implantation. The opposing forces of the two surfaces make the fusion device more stable.

4. The cage for posterior lumbar fusion according to claim 1 or 2, wherein: The front end of the fusion device body is an elliptical structure to facilitate oblique implantation of the fusion device body into the intervertebral space.

5. The cage for posterior lumbar fusion according to claim 1 or 2, wherein: The upper and lower surfaces of the fusion device body are non-parallel, with an included angle α, and the fusion device body is wedge-shaped with the left side lower than the right side.

6. The cage for posterior lumbar fusion according to claim 1, wherein: The fusion device body has a side hole on each of its left and right sides, and the side hole is located in the middle of the left and right sides.

7. The cage for posterior lumbar fusion according to claim 1, wherein: The fusion device body is made of biocompatible PEEK material to provide sufficient strength and stability and to be compatible with the surrounding bone tissue.

8. The cage for posterior lumbar fusion according to claim 1, wherein: The fusion unit body is equipped with two developing needles, which are metal structures visible under fluoroscopy, located at the center of the front end and the right side of the rear end of the fusion unit body.

9. The cage for posterior lumbar fusion according to claim 1, wherein: After implantation, the main body of the fusion device can be inserted obliquely and rotated to adjust to a horizontal position, thereby increasing the contact area with the vertebral endplate and maintaining the intervertebral height and the stability of the fusion device.

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