Intervertebral fusion cage

Abstract

The present application relates to a kind of intervertebral fusion cage, including body, with the first surface and the second surface of facing away, the body is provided with the bone graft cavity through the first surface and the second surface;Rotary shaft, with the body relatively rotatable connection, the axial end of rotary shaft respectively extends the first surface and second surface.Surperior fusion cage is used when in the process of intervertebral fusion surgery, when doctor needs secondary adjustment fusion cage position, rotary shaft remains unmoved, body can rotate around rotary shaft, since the two ends of rotary shaft are slightly higher than the surface of body, the extrusion and friction between body and vertebral endplate during body rotation will reduce, reduce the probability of body escape;Also reduce the difficulty of doctor rotating and adjusting fusion cage during operation, reduce operation time.In addition, since reducing the secondary extrusion and friction to vertebral endplate, reduce the pain of patient.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to an interbody fusion device. Background Technology

[0002] In the treatment of thoracic and lumbar vertebral fractures, the most common fracture is intervertebral disc herniation. The commonly used treatment method is intervertebral fusion surgery, which is the replacement of the intervertebral disc. The intervertebral disc is replaced with an intervertebral fusion cage to restore the patient's normal physiological curvature, relieve the compression, and enable the patient to resume normal activities.

[0003] Currently, thoracolumbar interbody fusion devices used in the market can be divided into anterior and posterior approaches based on the surgical approach. The anterior approach is further divided into ALIF, DLIF, and the newest OLIF approach. The scope of each surgical approach is as follows: Figure 1 As shown, the OLIF surgical approach is gaining increasing market acceptance because it reduces patient trauma compared to the ALIF and DLIF surgical approaches.

[0004] Because OLIF focuses more on innovation in surgical approach, its products are structurally similar to DLIF surgical products, and there are no dedicated products. However, the surgical procedures for OLIF and DLIF are not entirely the same. In particular, OLIF surgery typically involves a vertical placement of the fusion device after implantation. Figure 2 The fusion cage (circled in the middle) is placed parallel to the coronal plane of the vertebral body; it is positioned between the two vertebral endplates, with small protrusions on its surface abutting against the endplates. Figure 2 The fusion device with the structure shown requires secondary rotation. The surgeon needs more time and effort to rotate and adjust the position of the fusion device. During this process, the small protrusions on the surface of the implanted fusion device will again compress and rub against the vertebral endplate. The small protrusions will wear down, which increases the chance of them dislodging. At the same time, the repeated compression and friction on the vertebral endplate will increase the patient's pain. Summary of the Invention

[0005] Therefore, it is necessary to provide an interbody fusion device to address the problem of secondary compression of the vertebral endplate during fusion device position adjustment.

[0006] An intervertebral fusion device includes a body having a first surface and a second surface facing away from each other, the body having a bone graft cavity penetrating the first surface and the second surface; and a rotating shaft rotatably connected to the body, the two ends of the rotating shaft extending out of the first surface and the second surface respectively.

[0007] When the aforementioned fusion device is used during intervertebral fusion surgery, if the surgeon needs to adjust the device's position, the rotation axis remains stationary while the main body can rotate around the axis. Because the two ends of the rotation axis are higher than the surface of the main body, the compression and friction between the main body and the vertebral endplate are reduced during rotation, lowering the chance of the main body dislocation. This also reduces the difficulty for the surgeon in rotating and adjusting the fusion device during surgery, shortening the operation time. Furthermore, the reduced secondary compression and friction on the vertebral endplate reduces patient discomfort.

[0008] In one embodiment, the body has a central hole extending through the geometric center of the first surface and the second surface, and the rotation shaft passes through the central hole.

[0009] In one embodiment, the first surface and the second surface are planar, sloping, curved, or a combination thereof.

[0010] In one embodiment, a first boss is provided on the first surface, and a second boss is provided on the second surface; a third boss extending out of the first surface and a fourth boss extending out of the second surface are respectively provided at both ends of the rotating shaft, wherein the height of the third boss relative to the first surface is greater than the height of the first boss, and the height of the fourth boss relative to the second surface is greater than the height of the second boss.

[0011] In one embodiment, the first boss and / or the third boss is a cone with the tip of the cone facing away from the first surface; the second boss and / or the fourth boss is a cone with the tip of the cone facing away from the second surface.

[0012] In one embodiment, the rotating shaft includes a first rotor and a second rotor that are detachably connected, a third boss is disposed on the first rotor, and a fourth boss is disposed on the second rotor.

[0013] In one embodiment, the rotating shaft and the body are coupled in a manner that allows them to rotate relative to each other about the shaft but not to move relative to each other axially. The first rotor includes a first abutment portion having the third boss, and the second rotor includes a second abutment portion having the fourth boss. The first abutment portion and the second abutment portion abut against the body from opposite directions.

[0014] In one embodiment, the body has a central hole penetrating the first surface and the second surface. The central hole includes a small-diameter hole in the middle and a first large-diameter hole and a second large-diameter hole at both ends. The first abutting portion is accommodated in the first large-diameter hole and abuts against the interface between the first large-diameter hole and the small-diameter hole. The second abutting portion is accommodated in the second large-diameter hole and abuts against the interface between the second large-diameter hole and the small-diameter hole.

[0015] In one embodiment, the body has an annular sidewall connecting the first surface and the second surface. The annular sidewall includes a front wall and a rear wall opposite to each other, and a left wall and a right wall connecting the front wall and the rear wall. A driving hole is provided on the rear wall, and the cross-section of the driving hole is non-circular.

[0016] In one embodiment, an annular arc groove is provided on the inner wall of the driving hole, and the diameter of the bottom of the annular arc groove is larger than the diameter of the circumcircle of the cross section of the driving hole.

[0017] An interbody fusion device includes a body with a bone graft cavity extending through the body; and a rotating shaft rotatably connected to the body, wherein the axial direction of the rotating shaft is consistent with the penetrating direction of the bone graft cavity, and both ends of the rotating shaft extend out of the body.

[0018] In one embodiment, the surface of the body near both axial ends of the rotating shaft is provided with uneven regions, the uneven regions having a concave-convex structure, and the end faces of both axial ends of the rotating shaft are uneven surfaces, the uneven surfaces being formed with a concave-convex structure. Attached Figure Description

[0019] Figure 1 This is a schematic diagram showing the access range of commonly used surgical approaches.

[0020] Figure 2 This is a schematic diagram of the fusion device implanted using the OLIF procedure.

[0021] Figure 3 This is a perspective view of a thoracolumbar intervertebral fusion device according to an embodiment of the present invention.

[0022] Figure 4 This is an exploded view of a thoracolumbar interbody fusion device according to an embodiment of the present invention.

[0023] Figure 5 This is a three-dimensional view of the body of the thoracolumbar intervertebral fusion device.

[0024] Figure 6 for Figure 5 The top view of the main body shown.

[0025] Figure 7 for Figure 6 A cross-sectional view along the AA direction.

[0026] Figure 8 for Figure 7 A magnified view of section X in the middle.

[0027] Figure 9 for Figure 5 The right view of the main body shown.

[0028] Figure 10 This is a schematic diagram of a thoracolumbar intervertebral fusion cage under compressive force.

[0029] Figure 11 This is a schematic diagram of a thoracolumbar interbody fusion cage subjected to shear force.

[0030] Figure 12 This is a schematic diagram of a thoracolumbar interbody fusion cage subjected to torsional force.

[0031] Figure 13 This is a three-dimensional view of the first central rotor.

[0032] Figure 14 This is the front view of the first central rotor.

[0033] Figure 15 for Figure 14 A sectional view along the BB direction.

[0034] Figure 16 This is a three-dimensional view of the second central rotor.

[0035] Figure 17 This is the front view of the second central rotor.

[0036] Figure 18 for Figure 17 A cross-sectional view along the CC direction.

[0037] The corresponding numbers of the relevant components in the diagram are as follows:

[0038] 100. Thoracolumbar interbody fusion cage; 10. Body; 110. First surface; 111. Bone graft cavity; 112. Central hole; 113. Mounting hole; 1131. Small diameter hole; 1132. First large diameter hole; 1133. Second large diameter hole; 114. First boss; 120. Second surface; 121. Second boss; 130. Annular sidewall; 131. Anterior wall; 132. Posterior wall; 133. Left wall; 134. Right wall; 1 35. Drive hole; 136. Connecting hole; 137. Annular groove; 20. Rotating shaft; 210. First rotor; 211. First shaft; 212. First abutting part; 213. First mating part; 2132. Hook; 214. Third boss; 220. Second rotor; 221. Second shaft; 222. Second abutting part; 223. Second mating part; 2231. Stepped surface; 224. Fourth boss; 30. Development line. Detailed Implementation

[0039] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0040] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying 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 limitations on this invention.

[0041] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0042] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0043] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0044] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0045] Embodiments of the present invention provide a thoracolumbar interbody fusion cage 100 for interbody fusion surgery, more specifically for OLIF surgery. Figure 3 and Figure 4 As shown, the thoracolumbar intervertebral fusion device 100 includes a body 10, a rotating shaft 20 rotatably connected to the body 10, and a radiopaque line 30 mounted on the body 10.

[0046] Combination Figure 4 and Figure 5 As shown, the body 10 has a first surface 110 and a second surface 120 that are opposite to each other, and an annular sidewall 130 connecting the first surface 110 and the second surface 120. The first surface 110 and the second surface 120 can be planar, sloping, or curved. A planar shape means that the first surface 110 and the second surface are two parallel planes; a sloping shape means that both the first surface 110 and the second surface 120 are formed by two planes joined together to form a pointed roof shape that is higher in the middle and lower on both sides; a curved shape means that both the first surface 110 and the second surface 120 are curved surfaces composed of a single-direction arc or a combination of multiple-direction arcs. The first surface 110 and the second surface 120 can also be a combination of the three shapes, for example, the first surface 110 is a plane and the second surface 120 is a curved surface. Preferably, both the first surface 110 and the second surface 120 are curved surfaces.

[0047] like Figure 5 and Figure 6 As shown, a bone graft cavity 111 for receiving bone graft material is provided through the first surface 110 and the second surface 120. The bone graft material includes autologous bone, allogeneic bone, or bone graft substitutes, but is not limited to the above materials. The annular sidewall 130 includes an opposing anterior wall 131 and a posterior wall 132, and a left wall 133 and a right wall 134 connecting the anterior wall 131 and the posterior wall 132. A drive hole 135 is provided on the posterior wall 132. The drive hole 135 is used in conjunction with a fitting device so that the body 10 can be inserted between a pair of vertebral endplates by holding the fitting device. The anterior wall 131 is configured with an arc-shaped tip to facilitate the insertion of the fusion device into the intervertebral space during surgery.

[0048] The rotating shaft 20 is rotatably connected to the body 10, wherein, for example... Figure 10 As shown, the two ends of the rotating shaft 20 extend beyond the first surface 110 and the second surface 120, respectively. That is, the two ends of the rotating shaft 20 are higher than the first surface 110 and the second surface 120, respectively. If the maximum axial length of the rotating shaft 20 is defined as d1, and the maximum vertical distance between the first surface 110 and the second surface 120 of the body 10 is defined as d2, then d1 is set to be slightly larger than d2. The maximum vertical distance between the first surface 110 and the second surface 120 refers to the distance along the axial direction of the rotating shaft 20. When the fusion device is placed between a pair of vertebral endplates, the two ends of the rotating shaft 20 can abut against the vertebral endplates.

[0049] In this embodiment, there are two bone graft cavities 111, and the rotating shaft 20 is located between the two bone graft cavities 111. Furthermore, the rotating shaft 20 is approximately located at the center of the main body 10. Figure 4 As shown, the body 10 is positioned between the two bone graft cavities 111 with a central hole 112 penetrating through the first surface 110 and the second surface 120 to accommodate the rotating shaft 20. Preferably, the central hole 112 penetrates the geometric center of the first surface 110 and the second surface 120, so that the rotating shaft 20 is located at the geometric center of the body 10. Figure 4 and Figure 5 As shown, the first surface 110 of the main body 10 also has five mounting holes 113 around the two bone graft cavities 111. Figure 3 and Figure 4 As shown, each mounting hole 113 is fitted with a radiopaque line 30 for positioning the fusion device after it has been implanted into the intervertebral space.

[0050] In addition, combined Figure 3 and Figure 4 As shown, the left wall 133 and the right wall 134 are respectively provided with connecting holes 136 that connect the bone graft cavity 111 to the outside. After the fusion device is implanted into the intervertebral space, the bone graft material in the bone graft cavity 111 can fuse with human tissue in the circumferential direction of the rotation axis 20.

[0051] When the aforementioned fusion device is used during intervertebral fusion surgery, if the surgeon needs to adjust the device's position, the rotation axis 20 remains stationary while the main body 10 can rotate around the rotation axis 20. Since the axial ends of the rotation axis 20 are slightly higher than the surface of the main body 10, the compression friction between the main body 10 and the vertebral endplate is reduced during rotation, lowering the likelihood of the main body 10 dislodging. Simultaneously, the rotation of the main body 10 around the rotation axis 20 reduces the difficulty for the surgeon in rotating and adjusting the fusion device during surgery, thus shortening the surgical time. Furthermore, the reduced secondary compression friction on the vertebral endplate reduces patient discomfort.

[0052] Combination Figure 5 and Figure 7 As shown, a first protrusion 114 is provided on the first surface 110, and a second protrusion 121 is provided on the second surface 120. Both the first protrusion 114 and the second protrusion 121 are used to abut against the vertebral endplate to better position the body 10 of the fusion device. Multiple first protrusions 114 are provided, distributed in the area of ​​the first surface 110 other than the bone graft cavity 111 and the mounting hole 113. Multiple second protrusions 121 are provided, distributed in the area of ​​the second surface 120 other than the bone graft cavity 111 and the mounting hole 113.

[0053] like Figure 10 As shown, the rotating shaft 20 has a third protrusion 214 extending from the first surface 110 and a fourth protrusion 224 extending from the second surface 120 at both ends. The height of the third protrusion 214 relative to the first surface 110 is greater than the height of the first protrusion 114, and the height of the fourth protrusion 224 relative to the second surface 120 is greater than the height of the second protrusion 121. Through this method, the axial dimension of the rotating shaft 20 is greater than the axial dimension of the body 10, and both ends of the rotating shaft 20 extend beyond the body 10. The height of the third protrusion 214 relative to the first surface 110 refers to the minimum vertical distance from the top of the third protrusion 214 (the end furthest from the first surface 110) to the first surface 110. The height of the fourth protrusion 224 relative to the second surface 120 refers to the minimum vertical distance from the top of the fourth protrusion 224 (the end furthest from the second surface 120) to the second surface 120.

[0054] When the doctor needs to adjust the position of the fusion device for the second time, the rotating shaft 20 remains stationary. During the rotation of the body 10, the squeezing friction between the first protrusion 114 and the vertebral endplate will be reduced, and the squeezing friction between the second protrusion 121 and the vertebral endplate will be reduced. This reduces the wear of the protrusions, lowers the chance of the body 10 dislodging, and reduces the patient's pain.

[0055] In the above embodiment, the third protrusion 214 and the fourth protrusion 224 at both ends of the rotation shaft 20 are equivalent to uneven portions of the end faces of both ends of the rotation shaft 20 with concave and convex structures. The plurality of first protrusions 114 on the first surface 110 form an uneven region with a specific concave and convex structure near the rotation shaft 20, and the plurality of second protrusions 121 on the second surface 120 also form an uneven region with a specific concave and convex structure near the rotation shaft 20. These uneven regions abut against the vertebral endplates to better position the body 10 of the fusion device.

[0056] After the fusion device is implanted in the human body, when the patient resumes movement, from a biomechanical perspective, the fusion device will mainly be subjected to compressive forces, shear forces, and torsional forces. Specifically, such as... Figure 10 As shown, the direction of the compressive force is perpendicular to the first surface 110 and the second surface 120. Figure 11 As shown, the direction of the shear force is parallel to the first surface 110 and the second surface 120. Figure 12 As shown, the direction of the torsional force is along the circumference. If both the first boss 114 and the second boss 121 are subjected to a force in a single direction, then the first boss 114 and the second boss 121 will each play a good role in resisting the force.

[0057] In practice, during normal human activity, the forces acting on the fusion device are often not of a single type or direction, but rather a multi-directional composite force of three forces. Since the first protrusion 114, the second protrusion 121, the third protrusion 214, and the fourth protrusion 224 are located on different planes with varying heights, their anti-slip performance under compressive forces is effectively improved. Especially when the first surface 110 and the second surface 120 are curved, due to material anisotropy, the compressive force is strongest in the normal direction. Because the first protrusion 114 and the third protrusion 214 are respectively distributed on the curved first surface 110 and the second surface 120, they are always under normal force when subjected to compressive forces. Since the second protrusion 214 and the fourth protrusion 224 can rotate relative to the body 10, they can offset part of the torsional force borne by the body 10 through relative rotation when resisting torsional forces. Since the first boss 114 and the third boss 214 are respectively distributed on the arc-shaped first surface 110 and the second surface 120, when subjected to shear force, the more material on the force-bearing plane, the stronger its shear resistance. Therefore, compared with the boss structure located on the same plane, the arc-shaped distribution can better resist shear forces in different directions.

[0058] If the fusion assembly is simultaneously subjected to compressive and shear forces, the first boss 114 and the third boss 214 can effectively resist the compressive and shear forces. Similarly, if the fusion assembly is simultaneously subjected to compressive, shear, and torsional forces, the first boss 114 and the third boss 214 can effectively resist the compressive and shear forces, while the second boss 214 and the fourth boss 224 can reduce the torsional force applied to the body by rotation.

[0059] Furthermore, the structure of the first boss 114 is the same as that of the third boss 214. The identical structure means that the combined force acts on the same object, which helps to better withstand the combined force.

[0060] Furthermore, both the first boss 114 and the third boss 214 are cones, with the tips of the cones facing away from the first surface 110. Specifically, the cone can be a circular cone or a pyramidal shape. The cone has a large contact area with the first surface 110, reducing the probability of detachment; additionally, the cone's pointed shape disperses the force from the tip to the larger base of the cone when resisting force, thus better resisting the force. In some embodiments, the structures of the first boss 114 and the third boss 214 can also be different. In some embodiments, the shape of the first boss 114 or the third boss 214 can also be a truncated cone, a truncated square pyramid, a hemispherical shape, a spike, a regular or irregular concave or convex surface, a rough surface, etc., but preferably, they are cones with the same structure and uniformly distributed.

[0061] Similarly, taking the second boss 121 and the fourth boss 224 as examples, they are located at different heights relative to the second surface 120. All components of the composite force can be borne by the boss structure, which can counteract forces acting in different directions; further details are omitted. Furthermore, the structure of the second boss 121 is the same as that of the fourth boss 224, which helps to evenly distribute the composite force. Moreover, both the second boss 121 and the fourth boss 224 are cones, with the tips of the cones facing away from the second surface 120, to reduce the probability of detachment and better cope with the forces.

[0062] In some embodiments, combined with Figure 4 , Figure 13 and Figure 16 As shown, the rotating shaft 20 includes a first rotor 210 and a second rotor 220 that are detachably connected, a third boss 214 is provided on the first rotor 210, and a fourth boss 224 is provided on the second rotor 220.

[0063] Combination Figures 13 to 15 As shown, the first rotor 210 includes a first shaft 211, a first abutting portion 212, and a first docking portion 213, wherein the first abutting portion 212 and the first docking portion 213 are disposed at opposite ends of the first shaft 211, and a third boss 214 is disposed on the end face of the first abutting portion 212 opposite to the first shaft 211. The first docking portion 213 is specifically configured as an elastically retractable structure. The first docking portion 213 is provided with a hook portion 2132.

[0064] Combination Figures 16 to 18 As shown, the second rotor 220 includes a second shaft 221, a second abutment portion 222, and a second docking portion 223. The second abutment portion 222 and the second docking portion 223 are disposed at opposite ends of the second shaft 221, and a fourth boss 224 is disposed on the end face of the second abutment portion 222 opposite to the second shaft 221. Specifically, the second docking portion 223 has a connecting hole on the end of the second shaft 221, and the connecting hole is a stepped hole.

[0065] When the rotating shaft 20 is connected to the body 10, the first rotor 210 is inserted into the center hole 112 of the body 10 from the side of the first surface 110, and the second rotor 220 is inserted into the center hole 112 of the body 10 from the side of the second surface 120. At the same time, the first docking part 213 is contracted and deformed and inserted into the second docking part 223 and fixed in the second docking part 223 by elastic force, wherein the hook part 2132 hooks the stepped surface 2231 in the second docking part 223.

[0066] The first rotor 210 and the second rotor 220 are connected to form a rotating shaft 20, and the first abutting part 212 and the second abutting part 222 abut against the body 10 from opposite directions, so that the rotating shaft 20 and the body 10 can be rotated relative to each other but cannot move relative to each other axially, thus preventing the rotating shaft 20 from separating from the body 10.

[0067] like Figure 7 As shown, the central hole 112 of the body 10 specifically includes a small-diameter hole 1131 in the middle and a first large-diameter hole 1132 and a second large-diameter hole 1133 at both ends. When the first rotor 210 and the second rotor 220 are engaged with the central hole 112, the first abutting part 212 is accommodated in the first large-diameter hole 1132 and abuts against the interface between the first large-diameter hole 1132 and the small-diameter hole 1131, and the second abutting part 222 is accommodated in the second large-diameter hole 1133 and abuts against the interface between the second large-diameter hole 1133 and the small-diameter hole 1131. The dimensions of the first shaft 211 and the second shaft 221 are set to be smaller than the diameter of the small-diameter hole 1131 of the central hole 112. In this way, the body 10 will not detach from the rotating shaft 20 in the axial direction of the rotating shaft 20, and the body 10 and the rotating shaft 20 can rotate relative to each other.

[0068] In the above embodiments, the first mating portion 213 is an elastically retractable structure, which includes multiple inwardly retractable elastic portions. These elastic portions are plugged into the connection holes of the second mating portion 223. In other embodiments, the plugged-in connection between the first rotor 210 and the second rotor 220 can also be: the first mating portion 213 is a male plug configured with any structure, and the second mating portion 223 is configured as a corresponding female plug. In other embodiments, the first rotor 210 and the second rotor 220 can also be threaded together.

[0069] The fusion unit in the above embodiment has a split structure. Specifically, the rotating shaft 20, the developing line 30, and the body 10 are not integrally formed. The developing line 30 can be a mature product; the rotating shaft 20 and the body 10 only need to be able to rotate relative to each other. The rotating shaft 20 does not require a complex structural design, while the body 10 only needs to have a central hole 112 added to the body 10 of a traditional fusion unit. Therefore, the structure of each part is simple, the processing difficulty is low, and it is easy to achieve mass production.

[0070] In traditional thoracolumbar interbody fusion devices 100, the tail drive hole 135 has a threaded structure. The device needs to be implanted into the human body, and its material is usually polyetheretherketone (PEEK). Due to the limitations of the material (PEEK), the threaded structure may become misaligned when used with metal instruments, thereby damaging the threaded structure or even causing wire entanglement. This also makes the testing of the device difficult. Even if the inspector operates carefully, the above problems may still occur, resulting in product damage. During the operation, the doctor must screw the instrument into the tail threaded drive to achieve self-holding and locking functions. During this process, the above situation may occur, which will prolong the operation time and increase the patient's pain.

[0071] To solve the above technical problems, such as Figure 5 As shown, a driving hole 135 is provided on the rear wall 132 of the annular sidewall 130. The driving hole 135 is used in conjunction with the fusion device. During use, the fusion device is inserted into the driving hole 135 and implanted into the human body. During implantation, it can be adjusted as needed. Figure 9 Slightly rotate the fusion device in the direction indicated by the middle arrow.

[0072] The drive hole 135 is designed with a non-circular cross-section, such as a quadrilateral or hexagonal shape. Because the cross-section of the drive hole 135 is non-circular, the fusion device and the fitting device will not rotate relative to each other during use, ensuring the stability of the fusion device during implantation.

[0073] Furthermore, to prevent the fusion device from falling off the mating device during implantation, such as Figure 8 As shown, an annular groove 137 is also provided on the inner wall of the drive hole 135. The diameter of the bottom of the annular groove 137 is larger than the diameter of the circumcircle of the radial section of the drive hole 135. The diameter of the bottom of the annular groove 137 refers to the maximum radial diameter of the annular groove 137. The term "radial" refers to the radial direction of the drive hole 135. The shape of the annular groove 137 can be a part of a sphere, a part of an ellipsoid, or a part of another approximate sphere, or the side of a cylinder. The annular groove 137 is used in conjunction with the steel ball of the matching instrument. Without external force assistance, the instrument can hold the fusion device without falling, achieving a self-holding function. During the operation, the doctor only needs to use the matching fitting device as required, directly inserting it into the drive hole 135. Its self-holding performance will respond immediately, which can reduce the surgeon's installation time and the probability of product damage, reduce the difficulty of detection, and reduce the operation time.

[0074] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0075] It will be readily understood by those skilled in the art that although this application uses a thoracolumbar interbody fusion cage as an example for illustration, the design scheme and design concept of this application can also be used for other types of interbody fusion cages and play a similar role.

[0076] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. An interbody fusion cage for use in OLIF surgical approach, characterized in that, include The body has a first surface and a second surface that are opposite to each other. The body is provided with a bone graft cavity that penetrates the first surface and the second surface. The body has an annular sidewall that connects the first surface and the second surface. A driving hole is provided on the annular sidewall. A rotating shaft is rotatably connected to the body. The two axial ends of the rotating shaft extend out of the first surface and the second surface, respectively. The axial length of the rotating shaft is greater than the maximum vertical distance between the body and the first surface and the second surface. When the fusion device is placed between a pair of vertebral endplates, the two axial ends of the rotating shaft can abut against the vertebral endplates. The rotating shaft is driven by an external instrument through the driving hole to achieve secondary adjustment of the position of the intervertebral fusion device. The body has a central hole that passes through the geometric center of the first surface and the second surface, and the rotating shaft passes through the central hole; The annular sidewall includes a front wall and a rear wall opposite to each other, and a left wall and a right wall connecting the front wall and the rear wall, wherein the rear wall has a driving hole, and the cross-section of the driving hole is not circular.

2. The interbody fusion device according to claim 1, characterized in that, The first surface and the second surface are planar, sloping, curved, or a combination thereof.

3. The interbody fusion device according to claim 1, characterized in that, The first surface is provided with a first protrusion, and the second surface is provided with a second protrusion; the two ends of the rotating shaft are respectively provided with a third protrusion extending out of the first surface and a fourth protrusion extending out of the second surface, wherein the height of the third protrusion relative to the first surface is greater than the height of the first protrusion, and the height of the fourth protrusion relative to the second surface is greater than the height of the second protrusion.

4. The interbody fusion device according to claim 3, characterized in that, The first boss and / or the third boss are cones, with the tip of the cone facing away from the first surface; the second boss and / or the fourth boss are cones, with the tip of the cone facing away from the second surface.

5. The interbody fusion device according to claim 3, characterized in that, The rotating shaft includes a first rotor and a second rotor that are detachably connected, a third boss is disposed on the first rotor, and a fourth boss is disposed on the second rotor.

6. The interbody fusion device according to claim 5, characterized in that, The rotating shaft and the body are engaged in a manner that allows them to rotate relative to each other about the shaft but not to move relative to each other axially. The first rotor includes a first abutting portion having the third boss, and the second rotor includes a second abutting portion having the fourth boss. The first abutting portion and the second abutting portion abut against the body from opposite directions.

7. The interbody fusion device according to claim 6, characterized in that, The body has a central hole penetrating the first surface and the second surface. The central hole includes a small-diameter hole in the middle and a first large-diameter hole and a second large-diameter hole at both ends. The first abutting part is accommodated in the first large-diameter hole and abuts against the interface between the first large-diameter hole and the small-diameter hole. The second abutting part is accommodated in the second large-diameter hole and abuts against the interface between the second large-diameter hole and the small-diameter hole.

8. The interbody fusion device according to claim 1, characterized in that, The inner wall of the driving hole is provided with an annular arc groove, and the diameter of the bottom of the annular arc groove is larger than the diameter of the circumcircle of the cross section of the driving hole.

9. The interbody fusion device according to claim 1, characterized in that, Uneven areas are provided on the surface of the body near both ends of the axial direction of the rotating shaft. The uneven areas have a concave-convex structure. The end faces of both ends of the axial direction of the rotating shaft are uneven surfaces, which are formed into a concave-convex structure.

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