Endoscopic interbody fusion cage and adjusting method thereof

Abstract

The invention provides an endoscopic interbody fusion cage and an adjusting method thereof. The endoscopic interbody fusion cage is characterized in that a plurality of first screw holes are formed in a first vertebral plate; the lifting column comprises a plurality of lifting groups, threads are arranged on the outer surface of the lifting column, and the lifting column is rotatably connected with a first screw hole in the first vertebral plate through the threads; the driving device is a cylinder with threads on the surface; the transmission device comprises a plurality of gear sets with different diameters and tooth numbers, the gear sets are meshed with one another, threaded holes are formed in the centers of gears in the gear sets in a penetrating mode, and the transmission device is connected with the driving device in a meshed mode. One end of the steering device is fixedly arranged at the top of the lifting column; a third screw hole is formed in the second vertebral plate, and the other end of the steering device is fixedly connected with the second vertebral plate through a lead screw. According to the technical scheme, the technical problem that when left-right asymmetric angles exist between the upper vertebral plate and the lower vertebral plate, a traditional symmetric fusion cage cannot achieve mechanical load balanced transmission is effectively solved.

Description

Technical Field

[0001] The present invention relates to a medical device, and particularly to an intervertebral fusion cage. Background Art

[0002] An intervertebral fusion cage (Cage) is a core implant used in spinal surgery to achieve intervertebral fusion. Its original design intention is to treat diseases such as intervertebral disc degeneration and spondylolisthesis by restoring the height of the intervertebral space, reconstructing the physiological curvature of the spine, and providing a stable bone fusion environment. With the progress of material science and manufacturing technology, the fusion cage has evolved from early titanium alloy and PEEK (polyetheretherketone) to today's 3D printed porous titanium structure, gradually optimizing the elastic modulus matching, bone ingrowth ability, and intraoperative visibility. However, problems such as postoperative fusion cage displacement, subsidence, and nonunion still exist in clinical practice. The core contradiction lies in the insufficient adaptability of the geometric shape of the fusion cage to the individual anatomical structure of the patient. Especially when there is a left-right asymmetric angle (coronal plane tilt) between the upper and lower endplates, traditional symmetric fusion cages cannot achieve the balanced transmission of mechanical loads.

[0003] In cases of degenerative scoliosis or post-traumatic spinal deformity, the vertebral endplates often show a coronal plane tilt (left-right angle inconsistency), resulting in a "wedge-shaped" rather than an ideal parallel structure of the intervertebral space. If a symmetric fusion cage is forcibly implanted, the contact surface can only partially fit the endplate, and local stress concentration may accelerate endplate bone resorption, leading to inclined subsidence of the fusion cage. At the same time, asymmetric loads will interfere with the mechanical environment of bone healing and increase the risk of pseudoarthrosis formation. Although some manufacturers currently offer fusion cages of multiple specifications or adjustable designs, intraoperative angle adjustment depends on the surgeon's experience and lacks a quantitative matching method. Moreover, the curved surface radian of existing fusion cages is mostly designed based on population anatomical averages and is difficult to accurately adapt to the individualized endplate morphology. How to solve the left-right angle deviation of the endplate through the innovation of the fusion cage structure or preoperative digital modeling matching technology has become a key technical bottleneck for improving the success rate of complex spinal surgery. Summary of the Invention

[0004] The purpose of the present invention is to provide a microscopic intervertebral fusion cage and its adjustment method to solve the technical problem that traditional symmetric fusion cages cannot achieve the balanced transmission of mechanical loads when there is a left-right asymmetric angle (coronal plane tilt) between the upper and lower vertebral plates.

[0005] To solve the above problems, the present invention provides a microscopic intervertebral fusion device and its adjustment method, specifically including: a first lamina fixedly arranged on the first vertebral body of the human body, with a plurality of first screw holes provided on the first lamina; a lifting column, the lifting column includes a plurality of lifting groups, the outer surface of the lifting column is provided with threads, and the lifting column is rotatably connected to the first screw holes on the aforementioned first lamina through the threads; a driving device, the driving device is a column with threads on its surface; a transmission device, the transmission device includes a plurality of gear groups with different diameters and numbers of teeth, each gear group meshes with each other, and a threaded hole is provided through the center of each gear in each gear group, and the transmission device is meshed and connected to the driving device; a steering device, one end of the steering device is fixedly arranged on the top of the aforementioned lifting column; a second lamina, with a third screw hole provided on the second lamina, and the other end of the steering device is fixedly connected to the second lamina through a lead screw; a housing, the housing is arranged between the first lamina and the second lamina, and the housing is made of an elastic material.

[0006] Further, the microscopic intervertebral fusion device further includes a first gasket and a second gasket.

[0007] Further, the first gasket and the second gasket are provided with limiting holes through them, and the lifting column is arranged through the limiting holes.

[0008] Further, the first gasket and the second gasket are of a double-layer composite structure, including a hydroxyapatite coating facing the vertebral body and a silica gel buffer layer facing the housing, and an array of anchor points with a diameter of 50 - 80 μm is formed between the two layers through laser micro-welding.

[0009] Further, the multiple lifting groups of the lifting column include a first lifting group, a second lifting group, and a third lifting group. Among them, the first lifting group is a single lifting column, and both the second lifting group and the third lifting group are two lifting columns, and each lifting group is arranged in a pentagon with two sides perpendicular to each other.

[0010] Further, the multiple gear groups include a first gear group, a second gear group, and a third gear group. Each gear group is arranged in a pentagon with two sides perpendicular to each other, and the first lifting group, the second lifting group, and the third lifting group are respectively connected to the first gear group, the second gear group, and the third gear group through threads.

[0011] Further, the steering device includes: a steering column, a second screw hole, a fixing piece, and a steering shaft. One end of the steering column is provided with the second screw hole, and the other end is rotatably arranged on the steering shaft. The steering shaft is fixedly arranged on the fixing piece, and the fixing piece is fixedly arranged on the lifting column.

[0012] Further, the intervertebral fusion device further includes a lead screw, and the lead screw passes through the second screw hole and the third screw hole.

[0013] Furthermore, the elastic material of the housing is medical-grade silicone or polyurethane rubber, with an elastic modulus in the range of 10 - 50 MPa. The housing wall thickness is 2 - 5 mm and it is provided with a honeycomb shock-absorbing structure.

[0014] Furthermore, on the contact surface between the first lamina and the second lamina, there is an array of tapered bone spurs distributed in a staggered manner. The height of the bone spurs is 0.5 - 1.2 mm, the bottom diameter is 0.3 - 0.8 mm, and the spacing between adjacent bone spurs is 1.5 - 2 times the height of the bone spurs.

[0015] Furthermore, the housing is provided with a three-layer gradient structure: the outer layer is a poly(lactic-co-glycolic acid) anti-adhesion film, the middle layer is a silk fibroin woven mesh, and the inner layer is a sodium alginate hydrogel. The layers are combined through ionic cross-linking.

[0016] Furthermore, a method for adjusting a microscopic intervertebral fusion device includes the following steps: Step 1: Calculate the angle by which the lamina needs to be tilted according to the preoperative plan, and calculate the height that each lifting column needs to rise based on this angle; Step 2: Place a suitable gear set and a driving device; Step 3: Pass the lifting column and the steering device through the gear set and fix them in the first screw holes on the first lamina; Step 4: Fix the second lamina to the steering device; Step 5: Rotate the driving device to adjust the second lamina to a suitable angle.

[0017] Applying the technical solution of the present invention, the first lamina is fixedly arranged on the first vertebra of the human body. There are multiple first screw holes on the first lamina. The lifting column includes multiple lifting groups. The outer surface of the lifting column is provided with threads, and the lifting column is rotatably connected to the first screw holes on the aforementioned first lamina through the threads; the driving device is a column body with threads on its surface; the transmission device includes multiple gear sets with different diameters and numbers of teeth. The gear sets mesh with each other. There is a threaded hole passing through the center of each gear in each gear set. The transmission device is meshed and connected to the driving device; one end of the steering device is fixedly arranged at the top of the aforementioned lifting column; there are third screw holes on the second lamina, and the other end of the steering device is fixedly connected to the second lamina through a lead screw; the housing is arranged between the first lamina and the second lamina, and the housing is made of an elastic material. By adjusting the driving device, the rotation of the transmission device is driven. Under the action of the transmission device and the internal threads, the height of each lifting column changes. Due to the different numbers of teeth and diameters of the gears in the gear set, the height changes of each lifting column are different, causing the steering device to rotate, and then driving the first lamina to rotate, so that a certain angle is formed between the first lamina and the second lamina, to solve the technical problem that when there is a left-right asymmetric angle (coronal plane tilt) between the upper and lower laminae, the traditional symmetric fusion device cannot achieve balanced transmission of mechanical loads.

[0018] Compared with traditional intervertebral fusion devices, the intervertebral fusion device of the present invention can be adapted to more patients, especially in the case of patients with scoliosis where the left and right heights between the laminae are inconsistent. Moreover, the present invention can adjust the height of the spacer or adjust the thickness of the entire intervertebral fusion device by replacing gears of the same diameter, avoiding standardized manufacturing, saving manufacturing costs, and being able to adapt to more people. Finally, the present invention achieves precise adjustment and fixation, and precisely adjusts the height of the lifting column by calculating parameters such as the number of teeth and pitch in the driving device and the transmission device, and further precisely adjusts the angle between the first lamina and the second lamina. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 shows an assembly diagram of the intervertebral fusion device; Figure 2 shows a cross-sectional view of the intervertebral fusion device; Figure 3 shows an assembly diagram of the driving device and the transmission device; Figure 4 shows a front three-axis view and a cross-sectional view of the steering device; Among them, the above-mentioned accompanying drawings include the following reference numerals: 10, the first lamina; 101, the first screw hole; 20, the spacer; 201, the first spacer; 202, the second spacer; 203, the limiting hole; 30, the lifting column; 301, the first lifting column group; 302, the second lifting column group; 303, the third lifting column group; 40, the driving device; 50, the transmission device; 501, the first gear group; 502, the second gear group; 503, the third gear group; 60, the steering device; 601, the second screw hole; 602, the steering column; 603, the fixing piece; 604, the steering shaft; 70, the lead screw; 80, the second lamina; 801, the third screw hole; 90, the housing. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way restricts the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0021] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they specify the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0022] Unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions, and values set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that for the sake of convenience of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationships. In all the examples shown and discussed herein, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters denote like items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0023] As Figure 1 shown: A microscopic intervertebral fusion device includes: a first lamina 10 fixedly disposed on the first vertebral body of the human body, and a plurality of first screw holes 101 are provided on the first lamina; a lifting column 30, the lifting column includes a plurality of lifting groups, the outer surface of the lifting column is provided with threads, and the lifting column is rotatably connected to the first screw holes on the aforementioned first lamina through the threads; a driving device 40, the driving device is a columnar body with threads on its surface; a transmission device 50, the transmission device includes a plurality of gear groups with different diameters and numbers of teeth, the gear groups are meshed with each other, and threaded holes are provided through the centers of the gears in each gear group, and the transmission device is meshed with the threads on the driving device, so that during the rotation of the driving device, the transmission device also moves; a steering device 60, one end of the steering device is fixedly disposed on the top of the lifting column; a second lamina 80, a third screw hole 801 is provided on the second lamina, and the other end of the steering device is fixedly connected to the second lamina through a lead screw 70; a housing 90, the housing is disposed between the first lamina and the second lamina, and the housing is made of an elastic material. When in use, the driving device is rotated. Under the action of the threads, the gear groups rotate. Since the numbers of teeth and diameters of different gear groups are different, the rotation arcs are different. Under the action of the threads at the centers of the gear groups and the threads on the lifting column, different lifting columns will move up and down at different heights, driving the rotating device to rotate. Since the rotating device is fixed on the second lamina, the second lamina is tilted.

[0024] As Figure 2As shown, during the above adjustment process, since the height increase of the lifting column will cause the thickness of the entire fusion device to change, in order to dilute this part of the increase, a plurality of gaskets are provided above the first lamina, including a first gasket 201 and a second gasket 202. The gasket is provided with a limit hole 203 corresponding to the first lamina, and the lifting column is penetrated and arranged in the limit hole. The height deviation caused by the aforementioned adjustment angle is diluted by changing the height or quantity of the gasket. The first gasket and the second gasket are of a double-layer composite structure, including a hydroxyapatite coating facing the vertebral body and a silica gel buffer layer facing the housing, and an array of anchor points with a diameter of 50-80 μm is formed between the two layers through laser micro-welding.

[0025] As Figure 3 shown, the arrangement of the transmission device 50 and the lifting column 30 is a pentagon with two perpendicular sides. The multiple lifting groups of the lifting column include a first lifting group 301, a second lifting group 302, and a third lifting group 303. Among them, the first lifting group is a single lifting column, and the second and third lifting groups are both two lifting columns. Each lifting group is arranged in a pentagon with two perpendicular sides. The multiple gear groups include a first gear group, a second gear group, and a third gear group. Each gear group is arranged in a pentagon with two perpendicular sides. The first lifting group, the second lifting group, and the third lifting group are respectively connected to the first gear group, the second gear group, and the third gear group through threads. Among them, the transmission device includes a first gear group 501; a second gear group 502; a third gear group 503. The corresponding lifting columns include a first lifting column group 301; a second lifting column group 302; a third lifting column group 303. Threads are provided at the exact center of the gear group, and threads are provided on the surface of the lifting column. The two threads mesh with each other. Under the rotation of the driving device 40, since the diameter of the third gear group is smaller, it will rotate more circles, and thus drive the lifting column to move upward more.

[0026] As Figure 4 shown, the steering device includes: a steering column 602, a second screw hole 601, a fixing piece 603, and a steering shaft 604. One end of the steering column is provided with a second screw hole, and the other end is rotatably arranged on the steering shaft. The steering shaft is fixedly arranged on the fixing piece, and the fixing piece is fixedly arranged on the lifting column 30. The intervertebral fusion device further includes a lead screw 70, and the lead screw penetrates through the second screw hole 601 and the third screw hole 801.

[0027] The elastic material of the housing is medical-grade silica gel or polyurethane rubber, with an elastic modulus ranging from 10 to 50 MPa. The wall thickness of the housing is 2 to 5 mm and it is provided with a honeycomb shock-absorbing structure. The contact surface between the first lamina and the second lamina is provided with a staggered array of conical bone spurs. The height of the bone spurs is 0.5 to 1.2 mm, the bottom diameter is 0.3 to 0.8 mm, and the distance between adjacent bone spurs is 1.5 to 2 times the height of the bone spurs. The housing is provided with a three-layer gradient structure: the outer layer is a poly(lactic-co-glycolic acid) anti-adhesion film, the middle layer is a silk fibroin woven mesh, and the inner layer is a sodium alginate hydrogel. The layers are combined by ionic cross-linking.

[0028] A method for adjusting a microscopic intervertebral fusion device includes the following steps: Step 1: Calculate the angle by which the lamina needs to be tilted according to the preoperative plan, and calculate the height that each lifting column needs to rise based on this angle; Step 2: Place a suitable gear set and drive device; Step 3: Pass the lifting column and the steering device through the gear set and fix them in the first screw hole on the first lamina; Step 4: Fix the second lamina and the steering device; Step 5: Rotate the drive device to adjust the second lamina to a suitable angle. The specific adjustment process is as follows: The mapping relationship between the rotation amount of the screw and the rising height of each screw can be expressed by the following formula: For each gear set i (i = A, B, C), the relationship between the rising height hi of its lifting column and the rotation amount of the drive device (expressed in revolutions n) is: hi = (Na / Ni) * pi *n where Na is the number of teeth of the gear directly driven by the screw, Ni is the number of teeth of gear i, pi is the pitch of the lifting column at the center of gear i (the distance it rises per revolution), and n is the number of rotation circles of the drive device.

[0029] Through the above calculations, doctors can preset the angle in advance during the preoperative planning stage, design the diameter and number of teeth of the gears, the drive device, and the pitch of the lifting column, and calculate the height. If there is a deviation in the height during the angle adjustment process, the adjustment of the entire thickness of the intervertebral fusion device can be achieved through the adjustment of the gasket.

[0030] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by orientation words such as "front, back, up, down, left, right", "horizontal, vertical, perpendicular, horizontal", and "top, bottom" are usually based on the orientation or positional relationships shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description. Without contrary instructions, these orientation words do not indicate and imply that the devices or elements referred to must have a specific orientation or be constructed and operated in a specific orientation, so they should not be construed as limiting the protection scope of the present invention; the orientation words "inside, outside" refer to the inside and outside relative to the contour of each component itself.

[0031] For ease of description, spatial relative terms such as "above", "over", "on the upper surface", "upper", etc. may be used herein to describe the spatial positional relationship of one device or feature to other devices or features as shown in the figures. It should be understood that the spatial relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is inverted, a device described as "above" or "over" other devices or structures will then be positioned "below" or "under" the other devices or structures. Thus, the exemplary term "above" can include both the orientations of "above" and "below". The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the corresponding explanations for the spatial relative descriptions used herein will be made accordingly.

[0032] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of differentiating the corresponding components. Without additional statements, the above terms have no special meanings, and thus should not be construed as limiting the scope of protection of the present invention.

[0033] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A microscopic intervertebral fusion device, characterized in that, Comprising: A first lamina fixedly arranged on the first vertebral body of the human body, and a plurality of first screw holes are arranged on the first lamina; A lifting column, the lifting column includes a plurality of lifting groups, the outer surface of the lifting column is provided with threads, and the lifting column is rotatably connected to the first screw holes on the aforementioned first lamina through the threads; A driving device, the driving device is a columnar body with threads on its surface; A transmission device, the transmission device includes a plurality of gear groups with different diameters and numbers of teeth, and the gear groups are meshed with each other. Threaded holes are penetrated through the centers of the gears in each gear group, and the transmission device is meshed and connected with the aforementioned driving device; A steering device, one end of the steering device is fixedly arranged on the top of the aforementioned lifting column; A second lamina, a third screw hole is arranged on the second lamina, and the other end of the aforementioned steering device is fixedly connected to the second lamina through a lead screw; A housing arranged between the first lamina and the second lamina, and the housing is made of an elastic material.

2. The microscopic intervertebral fusion device according to claim 1, characterized in that, The microscopic intervertebral fusion device further includes a first gasket and a second gasket.

3. The microscopic intervertebral fusion device according to claim 2, wherein, Limit holes are penetrated through the first gasket and the second gasket, and the aforementioned lifting column is penetrated through the limit holes.

4. The microscopic intervertebral fusion device according to claim 2, characterized in that, The first gasket and the second gasket are of a double-layer composite structure, including a hydroxyapatite coating facing the vertebral body and a silica gel buffer layer facing the housing, and an array of anchor points with a diameter of 50-80 μm is formed between the two layers through laser micro-welding.

5. The microscopic intervertebral fusion device according to claim 1, characterized in that, The multiple lifting groups of the lifting column include a first lifting group, a second lifting group, and a third lifting group. Among them, the first lifting group is a single lifting column, and both the second lifting group and the third lifting group are two lifting columns. Each lifting group is arranged in a pentagon with two sides perpendicular to each other.

6. The microscopic intervertebral fusion device according to claim 5, characterized in that, The multiple gear groups include a first gear group, a second gear group, and a third gear group. Each gear group is arranged in a pentagon with two sides perpendicular to each other. The aforementioned first lifting group, second lifting group, and third lifting group are respectively connected to the first gear group, second gear group, and third gear group through threads.

7. The microscopic intervertebral fusion device according to claim 1, wherein The steering device includes: a steering column, a second screw hole, a fixing piece, and a steering shaft. One end of the steering column is provided with a second screw hole, and the other end is rotatably arranged on the steering shaft. The steering shaft is fixedly arranged on the fixing piece, and the fixing piece is fixedly arranged on the lifting column.

8. The microscopic intervertebral fusion device according to claim 7, characterized in that The intervertebral fusion device further includes a lead screw, and the lead screw penetrates through the second screw hole and the third screw hole.

9. The microscopic intervertebral fusion device according to claim 1, characterized in that, The elastic material of the housing is medical-grade silica gel or polyurethane rubber, its elastic modulus range is 10-50 MPa, the wall thickness of the housing is 2-5 mm and it is provided with a honeycomb shock-absorbing structure.

10. The microscopic intervertebral fusion device according to claim 1, characterized in that, The contact surfaces of the first lamina and the second lamina are provided with an array of tapered bone spurs distributed in a staggered manner. The height of the bone spurs is 0.5-1.2 mm, the bottom diameter is 0.3-0.8 mm, and the distance between adjacent bone spurs is 1.5-2 times the height of the bone spurs.

11. The microscopic intervertebral fusion device according to claim 1, characterized in that, The housing is provided with a three-layer gradient structure: the outer layer is a poly(lactic-co-glycolic acid) anti-adhesion film, the middle layer is a silk fibroin woven mesh, and the inner layer is a sodium alginate hydrogel. The layers are combined through ionic cross-linking.

12. A method for adjusting a microscopic intervertebral fusion device according to any one of claims 1-11, characterized in that, The adjustment method includes the following steps: Step 1: Calculate the angle of inclination required for the lamina according to the preoperative plan, and calculate the height that each lifting column needs to rise based on this angle; Step 2: Place a suitable gear set and a driving device; Step 3: Pass the lifting column and the steering device through the aforesaid gear set and fix them in the first screw holes on the first push plate; Step 4: Fix the second push plate and the steering device; Step 5: Rotate the driving device to adjust the second push plate to a suitable angle.

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