Artificial intervertebral disc

Abstract

An artificial intervertebral disc includes a first element, a second element, a third element, and a fourth element. The first element has a first top surface and a first bottom surface, and the first bottom surface has a first recess and a first hole. The second element includes a second stud and a second flange, the second flange having a second convex arc surface and a second concave arc surface. The third element has a third top surface and a third bottom surface, and the third hole penetrates the third top surface and the third bottom surface. The fourth element has a fourth recess and a fourth convex arc surface, and the outer side wall of the fourth element is provided with a fourth external thread. The second stud passes through the first hole, protrudes from the first top surface, the second convex arc surface abuts against the junction of the first hole and the first recess, the second stud is screwed into the third hole, and the fourth element is screwed into the first recess, the fourth convex arc surface facing the second concave arc surface.

Description

[Technical Field]

[0001] This invention relates to the field of medical technology, and in particular to an artificial intervertebral disc that is structurally robust, has a strong interlocking force with the spine, and can conform to the curvature of the spine. [Previous Technology]

[0002] Regarding degenerative disc disease of the cervical and lumbar spine, the main treatment currently used is the implantation of artificial intervertebral discs.

[0003] The structure of a conventional artificial intervertebral disc mainly includes a top plate and a bottom plate. The top plate and bottom plate usually have opposing concave and convex structures, which allow the top plate and bottom plate to fit together and move relative to each other, thereby adapting to the curvature of the spine when it bends. In addition, the surfaces of the top plate and bottom plate facing the vertebrae usually have teeth or serrated structures, which can be used to bite with the spine.

[0004] However, after being implanted in the spine for a period of time, artificial intervertebral discs often separate from the top plate and bottom plate due to various reasons, resulting in a loss of support for the spine.

[0005] For example, due to the patient's continued spinal atrophy and deterioration or due to the patient's poor posture, the top plate and bottom plate cannot fit together smoothly, or even the top plate and / or bottom plate may detach from the spine.

[0006] To improve the above problems, some manufacturers have designed a locking structure between the top plate and the bottom plate. However, this type of locking structure will actually hinder the relative sliding between the top plate and the bottom plate.

[0007] Those skilled in the art will understand that artificial intervertebral discs are very small. If the locking structure is designed to be small in order not to hinder the relative sliding between the top plate and the bottom plate, the locking effect cannot be effectively achieved. Although there are teeth or serrated structures between the top plate and the vertebra and between the bottom plate and the vertebra, due to poor design of the locking structure, the top plate and the bottom plate can still be pulled apart when the spine is repeatedly bent or the user's posture is poor.

[0008] Accordingly, how to develop an "artificial intervertebral disc" with a strong structure, strong interlocking force with the vertebrae, and conforming to the curvature of the spine is an issue that needs to be addressed by people in the relevant technical field.

New content

[0009] In one embodiment, the present invention proposes an artificial intervertebral disc, comprising: a first element having a first top surface and a first bottom surface parallel to the Z-axis, a first recess on the first bottom surface, a first internal thread on the inner sidewall of the first recess, a first hole parallel to the Z-axis penetrating the first top surface and communicating with the first recess, the inner diameter of the first hole being smaller than the inner diameter of the first recess, and a plurality of first teeth protruding from the first bottom surface, the Z-axis being a triaxial axis perpendicular to the X-axis and the Y-axis; a second element including a second stud having a second external thread, the axis of the second stud being parallel to the Z-axis, a second flange being provided at one axial end of the second stud, the second flange having a second convex arc surface and a second concave arc surface parallel to the Z-axis, the second stud being located on the second convex arc surface, and the outer diameter of the second flange being larger than the inner diameter of the first hole and the outer diameter of the second stud; A third element has a third top surface and a third bottom surface parallel to the Z-axis, a third hole parallel to the Z-axis penetrating the third top surface and the third bottom surface, the inner wall of the third hole having a third internal thread that can be screwed into the second external thread, and the third top surface having a plurality of third teeth protruding from the third top surface; and a fourth element has a fourth top surface and a fourth bottom surface parallel to the Z-axis, a fourth recess on the fourth top surface, a fourth convex arc protruding from the fourth recess parallel to the Z-axis, and a fourth external thread on the outer wall of the fourth element; thereby, a second stud passes through the first hole, the second stud protrudes from the first top surface, the second convex arc abuts against the adjacent part of the first hole and the first recess, the second stud is screwed into the third hole, the fourth external thread is screwed into the first internal thread, and the fourth convex arc faces the second concave arc.

Implementation Method

[0010] Please refer to Figures 1 to 4. One of the artificial intervertebral discs 100 provided in this invention includes a first element 10, a second element 20, a third element 30 and a fourth element 40.

[0011] The materials of the first element 10, the second element 20, the third element 30 and the fourth element 40 are designed according to actual needs, such as biocompatible metal or plastic.

[0012] Please refer to Figures 3, 4 and 5B. The first element 10 is parallel to the Z-axis and has a first top surface 11 and a first bottom surface 12. The X-axis, Y-axis and Z-axis are three mutually perpendicular axes.

[0013] The first element 10 has a first front side S11 and a first rear side S12 that are opposite each other. The lengths of the first front side S11 and the first rear side S12 are parallel to the X-axis. The length L11 of the first front side S11 is less than the length L12 of the first rear side S12, and the first front side S11 and the first rear side S12 are parallel to the Y-axis and have a distance D10.

[0014] A first left side S13 and a first right side S14 are arranged oppositely and symmetrically between the first front side S11 and the first rear side S12. The projections of the first front side S11, the first rear side S12, the first left side S13 and the first right side S14 onto the XY plane formed by the X-axis and the Y-axis are isosceles trapezoids.

[0015] Please refer to Figures 4 and 7. A first recess 13 is provided on the first bottom surface 12, and the inner sidewall of the first recess 13 has a first internal thread 14.

[0016] Please refer to Figures 4, 5B, 6 and 7. The first bottom surface 12 has a plurality of first teeth 16 protruding from the first bottom surface 12. Each first tooth 16 is a unidirectional ratchet, and the tooth tip 161 of each first tooth 16 faces the side of the first element 10 that has the first rear side edge S12.

[0017] The number and position of the first teeth 16 are designed according to actual needs. For example, as shown in Figures 4 and 5B, two rows of two teeth are symmetrically arranged around the first recess 13, for a total of four first teeth 16, but not limited to this.

[0018] Please refer to Figures 3, 4 and 7. A first hole 15 is parallel to the Z-axis, passes through the first top surface 11 and connects to the first recess 13. The inner diameter d15 of the first hole 15 is smaller than the inner diameter d13 of the first recess 13. The adjacent area between the first hole 15 and the first recess 13 has a chamfer C1.

[0019] Please refer to Figures 3, 4, and 7. The second element 20 includes a second stud 21 having a second external thread 211. The axis of the second stud 21 is parallel to the Z-axis. A second flange 22 is provided at one axial end of the second stud 21. The second flange 22 is parallel to the Z-axis and has opposing second convex arc surface 221 and second concave arc surface 222. The second stud 21 is located on the second convex arc surface 221.

[0020] Please refer to Figure 7. The outer diameter d22 of the second flange 22 is greater than the inner diameter d15 of the first hole 15 and the outer diameter d21 of the second stud 21. Both the second convex arc surface 221 and the second concave arc surface 222 are spherical surfaces. The second convex arc surface 221 and the second concave arc surface 222 are concentric, and the radius r222 of the second concave arc surface 222 is smaller than the radius r221 of the second convex arc surface 221.

[0021] Referring to Figures 3 and 5A, a hexagonal second groove 23 is provided at the other axial end of the second stud 21. After inserting a tool of a corresponding shape (not shown in the figures) into the second groove 23, the second element 20 can be rotated. It is understood that the shape of the second groove 23 is not limited to hexagon; any geometrically shaped groove can be used to mate with a tool of a corresponding shape.

[0022] Please refer to Figures 3, 4 and 5A. The third element 30 is parallel to the Z-axis and has a third top surface 31 and a third bottom surface 32.

[0023] The third element 30 has a third front side S31 and a third rear side S32, the lengths of which are parallel to the X-axis. The length L31 of the third front side S31 is less than the length L32 of the third rear side S32, and the third front side S31 and the third rear side S32 are parallel to the Y-axis with a distance D30.

[0024] A third left side S33 and a third right side S34 are arranged oppositely and symmetrically between the third front side S31 and the third rear side S32. The projections of the third front side S31, the third rear side S32, the third left side S33 and the third right side S34 on the XY plane form an isosceles trapezoid.

[0025] The projections of the first element 10 and the third element 30 onto the XY plane are approximately the same. For example, the projections of the first front side S11, the first rear side S12, the first left side S13, and the first right side S14 onto the XY plane correspond to and overlap with the projections of the third front side S31, the third rear side S32, the third left side S33, and the third right side S34 onto the XY plane.

[0026] Please refer to Figures 3 and 4. A third hole 35 passes through the third top surface 31 and the third bottom surface 32 parallel to the Z-axis. The inner wall of the third hole 35 has a third internal thread 351 that can be screwed into the second external thread 211.

[0027] Please refer to Figures 3, 5A, 6 and 7. The third top surface 31 is provided with a plurality of third teeth 36 protruding from the third top surface 31. Each third tooth 36 is a unidirectional ratchet, and the tooth tip 361 of each third tooth 36 faces the side of the third element 30 that has the third rear side S32.

[0028] The number and position of the third teeth 36 are designed according to actual needs. For example, as shown in Figures 3 and 5A, two rows of three teeth are symmetrically arranged around the third hole 35, for a total of six third teeth 36, but not limited to this.

[0029] Please refer to Figures 3, 4, and 7. The fourth element 40 has a fourth top surface 41 and a fourth bottom surface 42 parallel to the Z-axis. The fourth top surface 41 has a fourth recess 43. A fourth convex arc portion 44 protrudes parallel to the Z-axis and is disposed within the fourth recess 43. A fourth external thread 45 is provided on the outer side wall of the fourth element 40. The fourth convex arc portion 44 is a spherical surface.

[0030] Please refer to Figure 7. The radius r222 of the second concave arc surface 222 is the same as the radius r44 of the fourth convex arc portion 44. Therefore, after assembly, the second concave arc surface 222 can fit into the fourth convex arc portion 44.

[0031] Please refer to Figures 4 and 5B. The fourth bottom surface 42 has a hexagonal fourth groove 46. After inserting a tool of a corresponding shape (not shown in the figures) into the fourth groove 46, the fourth element 40 can be rotated. It is understood that the shape of the fourth groove 46 is not limited to hexagon; any geometric shape of groove can be used to mate with a tool of a corresponding shape.

[0032] Please refer to Figures 3 and 4. The first hole 15, the first recess 13, the second flange 22, the third hole 35, the fourth element 40, and the fourth convex arc 44 are all circular and coaxially arranged.

[0033] Please refer to Figures 8A to 8C to illustrate one assembly method of this creation.

[0034] As shown in Figures 8A and 8B, the second stud 21 of the second element 20 is first inserted through the first hole 15 of the first element 10 from the side of the first element 10 having the first bottom surface 12, so that the second stud 21 protrudes out of the first top surface 11 of the first element 10.

[0035] Then, as shown in Figures 8B and 8C, the second stud 21 is screwed into the third hole 35 of the third element 30.

[0036] Then, as shown in FIG8C, the fourth external thread 45 of the fourth element 40 is screwed into the first internal thread 14 of the inner sidewall of the first recess 13 of the first element 10 shown in FIG4.

[0037] Thus, the combined structure of the artificial intervertebral disc 100 shown in Figures 1 and 2 can be formed.

[0038] Please refer to Figures 6 and 7. In the artificial intervertebral disc 100 provided in this invention, the second stud 21 protrudes from the first top surface 11, the second convex arc surface 221 abuts against the chamfer C1 at the junction of the first hole 15 and the first recess 13, the second stud 21 is screwed into the third hole 35, the fourth external thread 45 is screwed into the first internal thread 14, and the fourth convex arc portion 44 faces the second concave arc surface 222.

[0039] The first element 10 and the fourth element 40 are detachably screwed together to form an assembly, and the second element 20 and the third element 30 are detachably screwed together to form an assembly. The second element 20 is sandwiched between the third element 30 and the fourth element 40, and the second flange 22 is sandwiched between the first element 40 and the fourth element 40. Since the radius r222 of the second concave arc surface 222 is the same as the radius r44 of the fourth convex arc portion 44, the fourth convex arc portion 44 and the second concave arc surface 222 can be completely fitted together.

[0040] Please refer to Figure 9. The artificial intervertebral disc 100 provided in this invention has a second element 20 that can swing within an angle θ. More precisely, since the contact surface between the second concave arc surface 222 and the fourth convex arc portion 44 is a spherical surface, the second element 20 and the third element 30 can not only swing left, right, forward, and backward relative to the first element 40 and the fourth element 40, but also swing in a spherical shape on the spherical arc surface of the fourth convex arc portion 44. In this way, the artificial intervertebral disc 100 can adapt to different spinal conditions.

[0041] Referring to Figure 10, the artificial intervertebral disc 100 is placed between the two vertebrae 202 and 204 with its first anterior side S11 and third anterior side S31 facing the spine 200. Each first tooth 16 and each third tooth 36 engages with the vertebrae 202 and 204 respectively. When the spine 200 bends, the two vertebrae 202 and 204 can drive the artificial intervertebral disc 100 to swing as shown in Figure 9.

[0042] Moreover, since the first tooth 16 and the third tooth 36 are both unidirectional ratchet teeth, they can increase the biting force between the teeth and the vertebrae 202 and 204 without loosening on their own.

[0043] In summary, as shown in Figure 9, the artificial intervertebral disc 100 provided by this invention is formed by the first element 10 and the fourth element 40 being separably screwed together to form an assembly, and the second element 20 and the third element 30 being separably screwed together to form an assembly. The second element 20 is sandwiched between the third element 30 and the fourth element 40, and the second flange 22 is sandwiched between the first element 40 and the fourth element 40, so that the structure of the artificial intervertebral disc 100 is strong and will not be pulled apart due to repeated bending of the spine or poor posture of the user, resulting in structural decomposition.

[0044] In addition, the first tooth 16 and the third tooth 36 are firmly engaged with the vertebrae, and the bite force between them is strong and can conform to the curvature of the spine, which can prevent the artificial intervertebral disc 100 from detaching from the spine.

[0045] Although the present invention has been disclosed above by way of embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the art may make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims. [Simplified Explanation of the Diagram]

[0046] Figure 1 is a three-dimensional structural diagram of the right side, rear side, and top side of one embodiment of the present invention. Figure 2 is a three-dimensional structural diagram of the right side, front side, and bottom side of the embodiment of Figure 1. Figure 3 is an exploded structural diagram of Figure 1. Figure 4 is an exploded structural diagram of Figure 2. Figure 5A is a top view of the embodiment of Figure 1. Figure 5B is a bottom view of the embodiment of Figure 1. Figure 6 is an enlarged structural diagram of section AA of Figure 5. Figure 7 is an exploded structural diagram of Figure 6. Figures 8A to 8C are schematic diagrams of continuous assembly of the embodiment of Figure 1. Figure 9 is a structural schematic diagram of the swinging of the third and second elements relative to the first and fourth elements of the embodiment of Figure 1. Figure 10 is a schematic diagram of the continuous movement of the embodiment of Figure 1 installed between the vertebrae.

Claims

1. An artificial intervertebral disc, comprising: a first element having a first top surface and a first bottom surface parallel to a Z-axis, a first recess on the first bottom surface, a first internal thread on the inner wall of the first recess, a first hole parallel to the Z-axis penetrating the first top surface and communicating with the first recess, the inner diameter of the first hole being smaller than the inner diameter of the first recess, the first bottom surface having a plurality of first teeth protruding from the first bottom surface, the Z-axis being a triaxial axis perpendicular to the X-axis and the Y-axis; a second element including a second stud having a second external thread, the axis of the second stud being parallel to the Z-axis, a second flange being provided at one axial end of the second stud, the second flange having a second convex arc surface and a second concave arc surface parallel to the Z-axis, the second stud being located on the second convex arc surface, the outer diameter of the second flange being larger than the inner diameter of the first hole and the outer diameter of the second stud; A third element has a third top surface and a third bottom surface parallel to the Z-axis, a third hole parallel to the Z-axis passing through the third top surface and the third bottom surface, the inner sidewall of the third hole having a third internal thread that can be screwed into the second external thread, and the third top surface having a plurality of third teeth protruding from the third top surface; and a fourth element has a fourth top surface and a fourth bottom surface parallel to the Z-axis, a fourth recess on the fourth top surface, a fourth convex arc protruding from the fourth recess parallel to the Z-axis, and a fourth external thread on the outer sidewall of the fourth element; thereby, a second stud passes through the first hole, the second stud protrudes from the first top surface, the second convex arc abuts against the adjacent part of the first hole and the first recess, the second stud is screwed into the third hole, the fourth external thread is screwed into the first internal thread, and the fourth convex arc faces the second concave arc.

2. The artificial intervertebral disc of claim 1, wherein the first hole and the first recess are adjacent to each other with a chamfer, and the second convex arc surface abuts against the chamfer.

3. The artificial intervertebral disc of claim 1, wherein the first hole, the first recess, the second flange, the third hole, the fourth element, and the fourth convex arc are all circular and coaxially arranged.

4. As requested in item 1, the artificial intervertebral disc, wherein: The first element has a first front side and a first rear side opposite to each other. The lengths of the first front side and the first rear side are parallel to the X-axis, and the length of the first front side is less than the length of the first rear side. The first front side and the first rear side are parallel to the Y-axis and are spaced apart. Between the first front side and the first rear side, there are a first left side and a first right side that are opposite to each other and symmetrically arranged. The projections of the first front side, the first rear side, the first left side, and the first right side onto the XY plane formed by the X-axis and the Y-axis are equal. The third element has a trapezoidal shape; and the third element has a third front side and a third rear side with opposite sides, the lengths of the third front side and the third rear side are parallel to the X-axis, the length of the third front side is less than the length of the third rear side, the third front side and the third rear side are parallel to the Y-axis with a distance between them, and a third left side and a third right side are oppositely and symmetrically arranged between the third front side and the third rear side. The projections of the third front side, the third rear side, the third left side and the third right side on the XY plane form an isosceles trapezoid.

5. The artificial intervertebral disc of claim 4, wherein the projections of the first anterior side, the first posterior side, the first left side, and the first right side onto the XY plane correspond to and overlap the projections of the third anterior side, the third posterior side, the third left side, and the third right side onto the XY plane.

6. As requested in item 4, the artificial intervertebral disc, wherein: Each of the first teeth is a unidirectional ratchet, and the tip of each of the first teeth faces the side of the first element having the first rear side. Each of the third teeth is a unidirectional ratchet, and the tip of each of the third teeth faces the side of the third element having the third rear side.

7. The artificial intervertebral disc of claim 1, wherein the radius of the second concave arc surface is the same as the radius of the fourth convex arc portion.

8. The artificial intervertebral disc of claim 1, wherein the second convex arc surface and the second concave arc surface are concentric, and the radius of the second concave arc surface is smaller than the radius of the second convex arc surface.

9. The artificial intervertebral disc of claim 1, wherein the second convex surface, the second concave surface and the fourth convex portion are all spherical surfaces.

10. The artificial intervertebral disc of claim 1, wherein the other axial end of the second stud is provided with a second groove of regular or irregular geometry, and / or the fourth bottom surface is provided with a fourth groove of regular or irregular geometry, which can respectively provide tools of corresponding shapes to be inserted to rotate the second element and / or the fourth element.

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