A posterior atlantoaxial lateral mass joint expandable adjustable fusion cage

Abstract

The application discloses a posterior-entry atlas-axis lateral mass joint expandable adjustable fusion cage and belongs to the technical field of spinal braces. The posterior-entry atlas-axis lateral mass joint expandable adjustable fusion cage comprises a main body, the main body comprises a converging end and a diverging end, the top and bottom surfaces between the converging end and the diverging end are smooth, a middle part of the diverging end is provided with an extrusion groove, and the top and bottom ends of the extrusion groove gradually narrow from the diverging end to the converging end to form an inclined contact surface. Through the design of the main body, a supporting rod and a tightener, two fusion cages are symmetrically knocked into the lateral mass joint position in a posterior-entry mode in the fusion operation of atlantoaxial dislocation, the bone grafting points of the lateral mass joint are increased, the conventional posterior bone grafting points are not affected, the structural support is high in early stability and is not prone to collapse, the bone grafting fusion rate is high, the bilateral mass joints are completely loosened and expanded before fusion, the atlantoaxial axial spacing is expanded, and the prying and resetting difficulty is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of spinal supports, and in particular relates to a posterior entry atlantoaxial lateral mass joint expandable and adjustable fusion device. Background Art

[0002] Atlantoaxial dislocation surgery is an interventional surgical method for treating atlantoaxial joint instability / dislocation / deformity. It is a type of minimally invasive surgery that can treat atlantoaxial dislocation caused by trauma, congenital malformation, degeneration, rheumatic disease, tumor, iatrogenic injury, etc. It uses the method of implanting a fusion device and a stent at the dislocation site to relieve the compression of the spinal canal caused by the collapse of the vertebral joints.

[0003] The most commonly used surgical methods are bone grafting and fusion between the posterior arch of the atlas and the axis lamina and block bone support bone grafting and fusion between the occipital bone and the axis lamina. However, the posterior granular or strip bone grafting used in the fusion between the posterior arch of the atlas and the axis lamina can only be flatly laid, without supporting force, and requires an external extrusion structure, which causes posterior vertebra compression and difficulty in opening the mouth. The block bone support bone grafting and fusion between the occipital bone and the axis lamina uses posterior block bone grafting, which has high trimming requirements and poor bone surface fit. In addition, simple posterior bone grafting does not take into account the fusion of the anterior column, while anterior bone grafting requires opening a wound from the patient's mouth, and the operating space and field of view are relatively narrow. During the operation, the axial distance is only opened by a screwdriver for reduction, and a fixed-size fusion device can be inserted only after the distance is tested with a trial mold. The operation steps are cumbersome and the operation is difficult. In view of this, a posterior-entry atlantoaxial lateral mass joint distraction and adjustment fusion device is provided. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the disadvantages of the above-mentioned prior art and provide a posterior entry atlantoaxial lateral mass joint expandable and adjustable fusion device.

[0005] The technical solutions adopted to solve the above technical problems are:

[0006] A posterior entry atlantoaxial lateral mass joint expandable and adjustable fusion cage comprises:

[0007] The main body includes a convergent end and a divergent end, the top and bottom surfaces connected between the convergent end and the divergent end are smooth, the middle of the divergent end is provided with an extrusion groove, the top and bottom ends of the extrusion groove gradually narrow from the divergent end to the convergent end to form an oblique contact surface, and the middle of the main body is provided with a bone graft cavity penetrating the top and bottom surfaces;

[0008] A support rod, the support rod including a rotating shaft, the rotating shaft being located at an end of the support rod, the support rod being swung in the extrusion groove by the rotating shaft, and the top and bottom ends of the support rod slidingly contacting the inclined contact surface;

[0009] The tightener includes a middle rod with a positive threaded hole at the end, a reverse threaded groove on the circumferential outer wall of the middle rod, a drawstring sleeve on the circumferential outer wall of the middle rod, and an end of the drawstring fixedly connected to the end of the support rod away from the rotating shaft. The middle rod can rotate through the drawstring to drive the support rod to swing toward the tightening end;

[0010] The bone fusion promoting block, the main body also includes a middle seat, the axis position of the middle seat is provided with a mounting hole, the mounting hole and the bone grafting cavity are communicated with each other through an accommodating hole, and the bone fusion promoting block is built into the accommodating hole.

[0011] Among them, the fusion device holder is screwed into the reverse thread groove, the bone block is placed in the bone graft cavity, the fusion device is installed at the end of the fusion device holder, and a distraction nail is installed at the end of the distraction screw driver to align with the joint position of the atlas lateral mass joint and the axis lateral mass joint for preliminary separation, and the cartilage on the contact surface of the lateral joint is cleaned. The fusion device holder is used to knock the main body vertically from back to front into the joint of the atlas lateral mass joint and the axis lateral mass joint. The thickness of the convergent end is thinner and easier to knock in. As the divergent end is knocked in, the thickness of the fusion device between the atlas lateral mass joint and the axis lateral mass joint gradually increases, and the joint between the atlas lateral mass joint and the axis lateral mass joint is The gap is gradually enlarged, and the axis will be driven forward and reset as the fusion device is knocked in from back to front. After the fusion device is embedded in place, the fusion device holder is used to rotate the middle rod to tighten the pull belt, so that the strut swings toward the convergence end, and then squeezes the oblique contact surface to further expand the divergent end, so that the atlas lateral mass joint and the axis lateral mass joint are completely loosened and expanded. The atlas and axis are adjusted and completely pried and reset with a strut screwdriver, and the expansion amplitude of the divergent end is adjusted to achieve the required fusion distance, and the atlas and axis are in a horizontal position to complete the fusion and bone grafting action. The bone fusion promoting block in the subsequent receiving hole will be slowly released to promote the success rate of bone grafting fusion.

[0012] Furthermore, the main body has built-in support frame 1 and support frame 2, and the support frame 1 and support frame 2 are located at the two end corners of the convergence end. The middle rod is coaxially rotatably installed in the mounting hole, and a connecting hole for the pull belt to pass through is opened between the mounting hole and the extrusion groove.

[0013] Through the above technical solution, in order to improve the support stability, support frames 1 and 2 made of hard materials are separately embedded at the two ends of the convergence end where the force is greater during knocking-in and subsequent recovery. Support frames 1 and 2 adopt a cage frame structure, which reduces their own weight while ensuring the support strength and is not easy to collapse under pressure. The middle rod and the pull belt are completely wrapped in the installation hole and the connecting hole, and will not contact the external bone during the knocking-in process, ensuring the smooth progress of subsequent free adjustment.

[0014] Furthermore, the second support frame is provided with an internal threaded hole near the divergent end, the middle rod is screwed to the internal threaded hole through a reverse thread groove, the inner diameter of the mounting hole is larger than the maximum outer diameter of the middle rod, and the pull belt is sleeved on the outside of the middle rod away from the support rod.

[0015] Through the above technical solution, in order to realize the tightening and loosening of the strut, a specific configuration is disclosed, in which an internal threaded hole is provided on the second support frame, and the middle rod is screwed into the internal threaded hole. By rotating the middle rod, it can be gradually screwed into the internal threaded hole, so that the drawstring in the extrusion groove is pulled into the mounting hole, and then the strut is pulled toward the convergence end, so that the extrusion groove is compressed to expand the divergent end. Similarly, by reversing the middle rod to loosen the drawstring, the strut is reset to make the divergent end rebound and shrink.

[0016] Furthermore, the internal threaded hole is coaxially arranged with the accommodating hole, the middle rod passes through the internal threaded hole and extends into the accommodating hole, and a limit head is provided at one end of the middle rod located in the accommodating hole, the outer diameter of the limit head is larger than the inner diameter of the internal threaded hole, and the circumferential outer wall of the limit head is in sliding contact with the circumferential inner wall of the accommodating hole.

[0017] Through the above technical solution, in order to improve the success rate of bone fusion, during the process of the middle rod being screwed into the internal threaded hole, the limit head at the end of the middle rod will gradually be inserted into the accommodating hole, squeezing the bone fusion promoting block in the accommodating hole into the bone graft cavity. The bone fusion promoting block is in a colloidal or paste-like semi-solid state, and as it is squeezed, it will disperse into the contact surface between the bone block and the side block joint, so that the coverage area of ​​the bone fusion promoting block is larger, which can improve the progress and success rate of bone fusion.

[0018] Furthermore, the tightener also includes a relay tube, a threaded blind hole is opened in the middle of the relay tube, the middle rod is screwed and assembled with the relay tube through a reverse thread groove, the middle rod is located at one end outside the relay tube and is provided with a ring groove, the inner wall of the opening of the mounting hole away from the end of the accommodating hole is provided with a convex ring that cooperates with the ring groove, and the pull belt is fixedly connected to the outer wall of the open end of the relay tube away from the support rod.

[0019] Through the above technical solution, a specific configuration of a tightener is disclosed, in which the relay tube is a cylindrical structure with a blind hole at the end. When the middle rod rotates, it will gradually rotate out of the relay tube, while the position of the end of the middle rod remains unchanged, which will push the relay tube in the opposite direction. At this time, the relay tube will drive the pull belt to move away from the middle rod, so that the support rod is pulled to swing toward the convergence end. When the middle rod reverses, the relay tube can be reset, the pull belt can be relaxed, and then the support rod can be reset.

[0020] Furthermore, a smooth hole is provided at one end of the second carrier frame close to the diverging end, the circumferential outer wall of the relay cylinder is in sliding contact with the circumferential inner wall of the smooth hole, and the circumferential outer wall of the relay cylinder is in sliding contact with the circumferential inner wall of the accommodating hole.

[0021] Through the above technical solution, in order to ensure the pushing action of the bone fusion promoting block, the relay tube is slidably inserted into the smooth hole, and can be inserted into the accommodating hole as it slides, squeezing the bone fusion promoting block from the accommodating hole position into the bone graft cavity, and dispersed to the contact surface position of the bone block and the side block joint.

[0022] Furthermore, an arc plate is provided at one end of the support frame close to the convergence end, and the arc plate is embedded in the corner position of the convergence end away from the tightener side, and the arc outer wall of the arc plate is wrapped around the outside of the convergence end corner.

[0023] Through the above technical solution, in order to ensure smooth knock-in, the design of the arc plate can first knock into the position of the lateral mass joint joint at the convergence end to form a smooth arc surface, and can also improve the structural strength of the place, avoid deformation of the tip causing poor knock-in, and the metal arc plate is completely exposed and at the front end of the knock-in, which is convenient for the auxiliary personnel to observe the marking and development, and monitor the knock-in depth and direction at all times, so as to control the knock-in position and reduce the risk of damaging the spinal canal.

[0024] Furthermore, a support ear is provided at one end of the support bracket close to the diverging end, a rotary hole is provided in the middle of the support ear, and the end of the rotating shaft is rotatably installed in the rotary hole.

[0025] Through the above technical solution, in order to ensure the structural strength of the main body, the support frame is horizontally extended, and the structure of the end where the side block joint is more severely squeezed is targeted for reinforcement. In addition, a rotary hole is opened at the support ear position to ensure the stable installation of the rotating shaft position when the support rod swings, avoiding the deformation of the main body causing the rotating shaft to rotate poorly. The structural strength of the connection between the rotating shaft and the main body can also be changed to ensure that the position of the rotating shaft can remain stable when the support rod is subjected to radial reaction force during swinging.

[0026] Furthermore, the distance between the top and bottom ends of the support rod near the diverging end is greater than the distance between the top and bottom ends of the support rod near the convergent end to form an inclined guide surface, and the smooth surface of the main body is hingedly installed with an extrusion block on the swinging path of the support rod, and a lining block is installed on the side of the extrusion block facing the support rod.

[0027] Through the above technical solution, in order to adapt to the inclination of the lateral mass joint contact surface, multiple extrusion blocks are swing-installed on the smooth surface of the divergent end. When the strut swings to expand the divergent end, the lining block can be used to make the extrusion block protrude from the smooth surface and directly embed and contact the lateral mass joint contact surface, thereby performing overall clamping and limiting of the fusion device, and achieving high early stability.

[0028] Furthermore, the main body further comprises a top block, which is arranged on the vertical inner wall of the bone graft cavity facing the accommodating hole, and the surface of the top block adopts a porous structure.

[0029] Through the technical scheme, the top block is used to press the bone block in the bone graft cavity, the requirement for trimming the size of the bone block is reduced, the adaptability is high, the bone fusion promoting agent can be pre-filled in the porous structure of the top block and released slowly at the position of the top block, the bone fusion promoting agent in the opposite accommodating hole cannot diffuse to the whole periphery of the bone block, and the success rate and speed of bone fusion are improved.

[0030] The beneficial effects of the present application are as follows:

[0031] (1) In the fusion operation of atlantoaxial dislocation, the present application adopts the rear-entry type to symmetrically knock in two fusion cages at the lateral mass joint position, increases the lateral mass joint bone graft point, does not affect the conventional posterior bone graft site, has high early stability and is not easy to collapse, has high bone graft fusion rate, completely releases and spreads the bilateral mass joints before fusion, spreads the atlantoaxial axial distance, and reduces the difficulty of prying and reducing;

[0032] (2) In the bone graft position, the present application pre-arranges the bone fusion promoting block, places the bone fusion promoting block in the bone graft position together with the bone block during the knocking-in process, does not need to be arranged separately in the later period, and in the process of spreading the atlantoaxial axial distance, the pre-arranged bone fusion promoting block is extruded and dispersed into the joint between the bone block and the lateral mass joint, so that the bone fusion promoting block can be released around the bone block to promote the progress and success rate of the bone fusion in the later period;

[0033] (3) In order to ensure smooth knocking-in, the main body is designed to be uneven in thickness, rigid support structures are arranged at the thinner positions to prevent the main body from being deformed or collapsed under pressure, the front end can be developed to ensure the accuracy of the fusion cage, the extrusion block is adapted to the inclined direction of the lateral mass joint contact surface, provides stable support in the early stage, shares the internal pressure to avoid accidental slipping after the operation. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 is the first perspective structural view of the present application;

[0035] Figure 2 is the second perspective structural view of the present application;

[0036] Figure 3 is the cutaway view of the first state of the present application;

[0037] Figure 4 is the structural view of the second state of the present application;

[0038] Figure 5 is the cutaway view of the second state of the present application;

[0039] Figure 6It is a schematic diagram of the splitting between the support rod, the tightener and the second carrier frame of the present invention;

[0040] Figure 7 This is a schematic diagram of the state of installing another tightener of the present invention Figure 1 ;

[0041] Figure 8 This is a schematic diagram of the state of installing another tightener of the present invention Figure 2 ;

[0042] Figure 9 It is a schematic diagram of the structure between the support rod of the present invention, another tightener and the supporting frame;

[0043] Figure 10 It is a schematic cross-sectional view of the main body of the present invention;

[0044] Figure 11 This is a schematic structural diagram of a top block installed on the vertical side wall of the bone graft cavity facing the accommodating hole of the present invention;

[0045] Figure 12 It is a structural schematic diagram of the carrier frame 1 of the present invention.

[0046] Figure numerals: 1. Main body; 11. Converging end; 12. Smooth surface; 13. Middle seat; 14. Extrusion groove; 15. Oblique contact surface; 16. Divergent end; 17. Dispersion groove; 18. Mounting hole; 181. Convex ring; 19. Accommodation hole; 2. Support frame 1; 21. Arc plate; 3. Support rod; 31. Oblique guide surface; 32. Rotating shaft; 4. Extrusion block; 41. Liner block; 5. Middle rod; 51. Pull belt; 52. Positive threaded hole; 53. Reverse threaded groove; 54. Limiting head; 55. Relay tube; 56. Ring groove; 6. Bone grafting cavity; 7. Support frame 2; 71. Internal threaded hole; 72. Smooth hole; 8. Bone fusion promoting block; 9. Top block. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0048] like Figures 1-12 As shown, this embodiment provides a posterior-entry atlantoaxial lateral mass joint expandable and adjustable fusion device. To solve the problems of existing lateral mass joint fusion devices, reduce the use of trial molds, reduce the difficulty of anterior bone grafting, and improve the success rate of fusion, a specific configuration is provided:

[0049] Regarding Subject 1, refer to Figure 1 and Figure 2, the main body 1 is a rectangular structure when viewed from above. When viewed from the main perspective, one end is thick and the other end is thin, forming a wedge-shaped overall structure, wherein the thinner end is the convergent end 11 and the thicker end is the divergent end 16. The top and bottom surfaces connected between the convergent end 11 and the divergent end 16 adopt a smooth surface 12, wherein an extrusion groove 14 is provided in the middle of the divergent end 16, and the extrusion groove 14 extends horizontally toward the convergent end 11, with a depth approximately equal to one-third of the width of the main body 1, and the top and bottom ends of the extrusion groove 14 gradually narrow from the divergent end 16 to the convergent end 11 to form an oblique contact surface 15, that is, the inclination direction of the oblique contact surface 15 is consistent with the smooth surface 12, and both gradually narrow from the divergent end 16 to the convergent end 11, and a bone grafting cavity 6 is opened in the middle of the main body 1 that passes through the top and bottom surfaces. The bone grafting cavity 6 is square, which reduces the difficulty of cutting the bone block;

[0050] For the stay 3, see Figure 3 The support rod 3 includes a rotating shaft 32, which is rotatably connected to the main body 1. The support rod 3 is swingably installed in the extrusion groove 14 through the rotating shaft 32. Specifically, it is placed at the left opening position of the extrusion groove 14 along the divergent end 16. The rotating shaft 32 is located at the end of the support rod 3. The top and bottom ends of the support rod 3 slide in contact with the inclined contact surface 15. When the support rod 3 swings around the rotating shaft 32 toward the convergent end 11, it pushes the divergent end 16 to deform and expand toward the top and bottom directions. Therefore, the main body 1 should be made of a material with a certain deformability, such as plastic material, and a ceramic bio-coating is provided on the surface to prevent the body from having an rejection reaction;

[0051] For tighteners, see Figure 3 and Figure 5 The tightener includes a middle rod 5 with a positive threaded hole 52 at the end. The middle rod 5 is cylindrical, and a reverse threaded groove 53 is opened on the outer wall of the circumference of the middle rod 5. A pull belt 51 is sleeved on the outer wall of the circumference of the middle rod 5, wherein the end of the pull belt 51 is fixedly connected to the end of the support rod 3 away from the rotating shaft 32. When the middle rod 5 rotates, the pull belt 51 will be tightened, thereby driving the support rod 3 to swing toward the convergence end 11;

[0052] Regarding bone fusion promoting block 8, refer to Figure 10 The main body 1 also includes a middle seat 13, and a mounting hole 18 is opened at the axial position of the middle seat 13. The middle rod 5 is located in the mounting hole 18. The mounting hole 18 and the bone graft cavity 6 are connected to each other through the accommodating hole 19. The bone fusion promoting block 8 is built into the accommodating hole 19. The inner wall of the bone graft cavity 6 is opened with a dispersion groove 17 connected to the accommodating hole 19. The bone fusion promoting block 8 adopts a non-solid structure of colloid or paste. The bone fusion promoting block 8 in the accommodating hole 19 can be squeezed and dispersed into both sides of the bone graft cavity 6, so that the front right and left and right sides of the bone block are wrapped by the bone fusion promoting block 8.

[0053] The working principle of this embodiment is as follows:

[0054] During the operation, an incision is opened at the back of the neck, the soft tissue is separated to expose the atlas and axis positions, the fusion device holder is screwed into the reverse thread groove 53, the pre-cut bone block is placed in the bone graft cavity 6, the fusion device is installed at the end of the fusion device holder, and a distraction pin is installed at the end of the distraction screw driver to align the joint position of the atlas lateral mass joint and the axis lateral mass joint for preliminary separation, the cartilage on the contact surface of the lateral joint is cleaned, and the fusion device holder is used to vertically knock the main body 1 from back to front into the joint of the atlas lateral mass joint and the axis lateral mass joint (traditional surgery uses a distraction screw driver to pry to the required distance, and then inserts a trial mold to confirm whether the fusion device can be successfully inserted, which is a cumbersome process);

[0055] The top and bottom surfaces of the main body 1 are smooth 12, which reduces the resistance to knocking in. The converging end 11 is thinner, making it easier to align with the gap and knock in. As the diverging end 16 is knocked in, the thickness of the fusion device between the atlas lateral mass joint and the axis lateral mass joint gradually increases, and the joint between the atlas lateral mass joint and the axis lateral mass joint is gradually enlarged. As the fusion device is knocked in from back to front, the axis is driven forward and reduced (traditional surgery uses a screwdriver to perform the reduction action throughout the entire process, and then inserts the trial mold and fusion device after the reduction is completed, which is a cumbersome process);

[0056] After the fusion device is knocked into place, the fusion device holder is used to rotate the middle rod 5 to tighten the tension belt 51, so that the strut 3 swings toward the convergent end 11, and then squeezes the oblique contact surface 15 to further expand the divergent end 16, so that the atlas lateral mass joint and the axis lateral mass joint are completely loosened and stretched. Traditional surgery releases the lateral mass joint from the posterior arch of the axis, which easily leads to insufficient loosening of the anterior lateral mass joint, causing resistance to the anterior reduction of the axis. In this solution, after the fusion device is used to completely loosen the lateral mass joint, the screwdriver can be used to more easily adjust and completely pry and reduce the atlas and axis.

[0057] Adjust the expansion amplitude of the divergent end 16 to achieve the required fusion spacing, and adjust the expansion amplitudes of the two fusion devices respectively to adapt to the difference in cartilage polishing degree of the lateral mass joint contact surface, so that the atlas and axis are in a horizontal position (if the polishing depth of the left lateral mass joint contact surface is larger and the polishing depth of the right lateral mass joint contact surface is smaller, the opening amplitude of the left fusion device is increased to compensate for the polishing difference), complete the fusion and bone grafting action, and the bone fusion promoting block 8 in the subsequent accommodating hole 19 will be slowly released to promote the success rate of bone graft fusion.

[0058] In a further embodiment, in order to improve the support stability, refer to Figure 3The main body 1 is equipped with a supporting frame 1 2 and a supporting frame 2 7. The supporting frame 1 2 and the supporting frame 2 7 adopt a cage frame structure, which reduces their own weight while ensuring the supporting strength and is not easy to collapse under pressure. The supporting frame 1 2 and the supporting frame 2 7 are located at the two end corners of the convergence end 11. The two end positions of the convergence end 11 that are subjected to greater force during knocking in and subsequent recovery are separately embedded with the supporting frame 1 2 and the supporting frame 2 7 of the hard material, which can play a role in targeted structural reinforcement. Relative to fully paving high-strength structural materials, the manufacturing cost can be reduced. The middle rod 5 is coaxially rotatably installed in the mounting hole 18. A connecting hole for the pull belt 51 to pass through is provided between the mounting hole 18 and the extrusion groove 14. The middle rod 5 and the pull belt 51 are completely wrapped in the mounting hole 18 and the connecting hole. They will not contact the external bone during the knocking in process, thereby ensuring the smooth progress of subsequent free adjustment.

[0059] In a further embodiment, in order to achieve the tightening and loosening of the strut 3, a specific configuration is disclosed, referring to Figure 3 and Figure 6 The lock hole 71 is a hole in the center of the locking cam 76, which is a hole in the center of the locking cam 76, so that the locking cam 76 is locked and the locking cam 76 is locked.

[0060] In a further embodiment, in order to improve the success rate of bone fusion, referring to Figure 5 The internal threaded hole 71 is coaxially arranged with the accommodating hole 19, and the middle rod 5 passes through the internal threaded hole 71 and extends into the accommodating hole 19. A limiting head 54 is provided at one end of the middle rod 5 located in the accommodating hole 19. In the process of the middle rod 5 being screwed into the internal threaded hole 71, the limiting head 54 at the end of the middle rod 5 will gradually insert into the accommodating hole 19, squeezing the bone fusion promoting block 8 in the accommodating hole 19 into the bone grafting cavity 6. The outer diameter of the limiting head 54 is larger than the inner diameter of the internal threaded hole 71, and the circumferential outer wall of the limiting head 54 is in sliding contact with the circumferential inner wall of the accommodating hole 19. The bone fusion promoting block 8 is in a colloidal or paste-like semi-solid state. The sliding connection between the limiting head 54 and the circumferential inner wall of the accommodating hole 19 can ensure that the bone fusion promoting block 8 is completely pushed out. As it is squeezed, it will disperse into the contact surface between the bone block and the side block joint, so that the coverage area of ​​the bone fusion promoting block 8 is larger, which can improve the progress and success rate of bone fusion.

[0061] In a further embodiment, because the fusion device holder needs to be connected to the end of the middle rod 5, the length of the middle rod 5 rotated and retracted into the main body 1 will be limited by the fusion device holder. For example, if the distance between the fusion device holder and the front end surface of the main body 1 is short, the depth to which the middle rod 5 can be screwed in is also short. Therefore, a specific configuration of the tightener is disclosed, with reference to Figure 7 and Figure 9 When the middle rod 5 is reversed, the relay tube 55 can be reset, the pull belt 51 is relaxed, and the strut 3 is reset.

[0062] In a further embodiment, in order to ensure the pushing action of the bone fusion promoting block 8, refer to Figure 8 A smooth hole 72 is provided at one end of the carrier frame 2 7 near the divergent end 16, and the outer circumferential wall of the relay tube 55 is in sliding contact with the inner circumferential wall of the smooth hole 72. The relay tube 55 is slidably inserted into the smooth hole 72 and can be inserted into the accommodating hole 19 as it slides. The outer circumferential wall of the relay tube 55 is in sliding contact with the inner circumferential wall of the accommodating hole 19, squeezing the bone fusion promoting block 8 from the position of the accommodating hole 19 into the bone graft cavity 6 and dispersing it to the contact surface position of the bone block and the side block joint.

[0063] In a further embodiment, to ensure smooth typing, refer to Figure 12 The support frame 2 is provided with an arc plate 21 at one end near the convergence end 11. The design of the arc plate 21 can form a smooth arc surface at the position where the convergence end 11 is first knocked into the joint seam of the lateral mass, and can also improve the structural strength of the place, and avoid the deformation of the tip causing poor knocking. In addition, the arc plate 21 is embedded in the corner position of the convergence end 11 away from the tightener side. The arc outer wall of the arc plate 21 is wrapped around the outside of the corner of the convergence end 11. The arc plate 21 made of metal material (tantalum metal with a higher degree of body acceptance can be used to reduce the body's rejection reaction) is completely exposed and is at the front end of knocking, which is convenient for auxiliary personnel to observe the marking development and monitor the knocking depth and direction at all times, so as to control the knocking position and reduce the risk of damaging the spinal canal.

[0064] In a further embodiment, in order to ensure the structural strength of the main body 1, refer to Figure 5 and Figure 12A support ear is provided at one end of the support frame 2 near the divergent end 16, and the support frame 2 is extended horizontally to provide targeted structural reinforcement on the end where the lateral mass joint is more severely squeezed. In addition, a rotary hole is provided in the middle of the support ear, and the end of the rotating shaft 32 is rotatably installed in the rotary hole. When the support rod 3 swings, the installation position of the rotating shaft 32 can be ensured to be stable, avoiding the deformation of the main body 1 causing the rotating shaft 32 to rotate poorly. The structural strength of the connection between the rotating shaft 32 and the main body 1 can also be changed to ensure that when the support rod 3 swings and the rotating shaft 32 is subjected to a radial reaction force, the position of the rotating shaft 32 can remain stable.

[0065] In a further embodiment, in order to adapt to the inclination of the lateral mass joint contact surface, reference is made to Figure 3 and Figure 4 The distance between the top and bottom ends of the strut 3 near the divergent end 16 is greater than the distance between the top and bottom ends of the strut 3 near the convergent end 11, forming an inclined guide surface 31. The smooth surface 12 of the main body 1 is located on the swinging path of the strut 3 and is hingedly installed with an extrusion block 4. The extrusion block 4 is installed on the side opposite to the strut 3. A lining block 41 is installed. At the smooth surface 12 at the divergent end 16 position, multiple extrusion blocks 4 are swingingly installed. When the strut 3 swings to expand the divergent end 16, the lining block 41 can be used to make the extrusion block 4 protrude from the smooth surface 12 and directly embed and contact the side mass joint contact surface. Because the side mass joint contact surface is high in front and low in back, after the fusion device is knocked into the side mass joint joint, an extrusion block 4 is set at the front corner position of the divergent end 16 (the corner position of the main body 1 where the free end of the strut 3 is located), which can limit the fusion device as a whole and has high early stability.

[0066] In a further embodiment, referring to Figure 11 The main body 1 also includes a top block 9, which is made of elastic material. The top block 9 presses the smaller bone block forward into the bone graft cavity 6. When the bone block is larger, the top block 9 can be squeezed and deformed to be smoothly inserted into the bone graft cavity 6, reducing the requirements for the trimming size of the bone block and having strong adaptability. The top block 9 is arranged on the vertical inner wall of the bone graft cavity 6 facing the accommodating hole 19. The surface of the top block 9 adopts a porous structure. The bone fusion promoter can be pre-filled in the porous structure of the top block 9 and slowly released at the top block 9 position to prevent the bone fusion promoting block 8 in the opposite accommodating hole 19 from diffusing to the posterior side position of the bone block, thereby improving the success rate and rate of bone fusion.

[0067] The above are only preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention.

Claims

1. A posterior entry atlantoaxial lateral mass joint expandable and adjustable fusion cage, characterized in that: include: A main body (1), the main body (1) comprising a convergent end (11) and a divergent end (16), the top and bottom surfaces connected between the convergent end (11) and the divergent end (16) being smooth surfaces (12), an extrusion groove (14) being provided in the middle of the divergent end (16), the top and bottom ends of the extrusion groove (14) gradually narrowing from the divergent end (16) to the convergent end (11) to form an oblique contact surface (15), and a bone grafting cavity (6) penetrating the top and bottom surfaces being provided in the middle of the main body (1); A support rod (3), the support rod (3) comprising a rotating shaft (32), the rotating shaft (32) being located at an end of the support rod (3), the support rod (3) being swingably mounted in the extrusion groove (14) via the rotating shaft (32), and the top and bottom ends of the support rod (3) slidingly contact the inclined contact surface (15); A tightener, comprising a middle rod (5) with a positive threaded hole (52) formed at an end thereof, a reverse threaded groove (53) formed on a circumferential outer wall of the middle rod (5), a drawstring (51) sleeved on the circumferential outer wall of the middle rod (5), an end of the drawstring (51) fixedly connected to an end of the support rod (3) away from the rotating shaft (32), and the middle rod (5) can rotate through the drawstring (51) to drive the support rod (3) to swing toward the convergence end (11); The bone fusion promoting block (8) is provided with a middle seat (13) and a mounting hole (18) is provided at an axial position of the middle seat (13). The mounting hole (18) and the bone graft cavity (6) are connected to each other through a receiving hole (19), and the bone fusion promoting block (8) is built into the receiving hole (19).

2. The posterior entry atlantoaxial lateral mass joint expandable and adjustable fusion cage according to claim 1, characterized in that: The main body (1) is equipped with a supporting frame 1 (2) and a supporting frame 2 (7), and the supporting frame 1 (2) and the supporting frame 2 (7) are located at the two end corners of the convergence end (11). The middle rod (5) is coaxially rotatably mounted in the mounting hole (18), and a connecting hole for the pull belt (51) to pass through is provided between the mounting hole (18) and the extrusion groove (14).

3. The posterior entry atlantoaxial lateral mass joint expandable and adjustable fusion cage according to claim 2, characterized in that: The second carrier frame (7) is provided with an internal threaded hole (71) at one end close to the divergent end (16), and the middle rod (5) is screwed to the internal threaded hole (71) through a reverse thread groove (53). The inner diameter of the mounting hole (18) is larger than the maximum outer diameter of the middle rod (5), and the end of the pull belt (51) away from the support rod (3) is sleeved on the outside of the middle rod (5).

4. The posterior entry atlantoaxial lateral mass joint expandable and adjustable fusion cage according to claim 3, characterized in that: The internal threaded hole (71) and the accommodating hole (19) are coaxially arranged, and the middle rod (5) passes through the internal threaded hole (71) and extends into the accommodating hole (19). One end of the middle rod (5) located in the accommodating hole (19) is provided with a limit head (54), the outer diameter of the limit head (54) is larger than the inner diameter of the internal threaded hole (71), and the circumferential outer wall of the limit head (54) is in sliding contact with the circumferential inner wall of the accommodating hole (19).

5. The posterior entry atlantoaxial lateral mass joint expandable and adjustable fusion cage according to claim 2, characterized in that: The tightener also includes a relay tube (55), a threaded blind hole is provided in the middle of the relay tube (55), the middle rod (5) is screwed and assembled with the relay tube (55) through a reverse thread groove (53), the middle rod (5) is provided with an annular groove (56) at one end outside the relay tube (55), the mounting hole (18) is provided with a convex ring (181) that cooperates with the annular groove (56) at the inner wall of the opening at one end away from the accommodating hole (19), and the drawstring (51) is fixedly connected to the outer wall of the open end of the relay tube (55) at one end away from the support rod (3).

6. The posterior entry atlantoaxial lateral mass joint expandable and adjustable fusion cage according to claim 5, characterized in that: The second carrier frame (7) is provided with a smooth hole (72) at one end close to the diverging end (16), the circumferential outer wall of the relay tube (55) is in sliding contact with the circumferential inner wall of the smooth hole (72), and the circumferential outer wall of the relay tube (55) is in sliding contact with the circumferential inner wall of the accommodating hole (19).

7. The posterior entry atlantoaxial lateral mass joint expandable and adjustable fusion cage according to claim 2, characterized in that: The supporting frame (2) is provided with an arc plate (21) at one end close to the convergence end (11), and the arc plate (21) is embedded in the corner position of the convergence end (11) away from the tightener side, and the arc outer wall of the arc plate (21) is wrapped around the outside of the corner of the convergence end (11).

8. The posterior entry atlantoaxial lateral mass joint expandable and adjustable fusion cage according to claim 2, characterized in that: The support frame (2) is provided with a support ear at one end close to the diverging end (16), and a rotation hole is provided in the middle of the support ear. The end of the rotating shaft (32) is rotatably installed in the rotation hole.

9. The posterior entry atlantoaxial lateral mass joint expandable and adjustable fusion cage according to claim 1, characterized in that: The distance between the top and bottom ends of the support rod (3) near the diverging end (16) is greater than the distance between the top and bottom ends of the support rod (3) near the convergent end (11) to form an inclined guide surface (31). The smooth surface (12) of the main body (1) is hingedly mounted with an extrusion block (4) on the swinging path of the support rod (3). A lining block (41) is mounted on the side of the extrusion block (4) facing the support rod (3).

10. The posterior entry atlantoaxial lateral mass joint expandable and adjustable fusion cage according to claim 1, characterized in that: The main body (1) further comprises a top block (9), which is arranged on a vertical inner wall of the bone graft cavity (6) facing the accommodating hole (19), and the surface of the top block (9) adopts a porous structure.

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