Mobile spinal implants used in total artificial disc replacement

Abstract

A mobile spinal implant is placed between vertebrae to replace a degenerated intervertebral disc. The mobile spinal implant has a pair of endplates sandwiching a core and an outer nucleus, with the core concentrically located within the outer nucleus. The outer nucleus encloses and properly seals the core, maintaining adequate elasticity and flexibility to facilitate physiological movement. The core is made of an elastic material and acts as a solid septum to resist and withstand local pressures and other forces. The endplates provide fixation and fusion with adjacent vertebrae and maintain the core and outer nucleus in their position. The mobile spinal implant restores the degenerated intervertebral disc to its normal height and function while preserving normal vertebral mobility.

Description

Technical Field

[0001] This invention relates to an implant for the human body, and more particularly to a movable spinal implant for use in total artificial disc replacement. Background Technology

[0002] Spinal implants are used to treat degenerative disc disease (DDD) or other disc injuries. Spinal fusion is a widely used treatment for pain relief, but it can limit a patient's mobility and range of motion. Total intervertebral disc replacement (TIP) is another technique for treating DDD or other disc injuries that preserves a patient's mobility and protects them from spinal fusion-related complications such as horizontal wear and tear on adjacent structures and disc degeneration. TIP is an effective solution for DDD and is gaining increasing attention due to the growing prevalence of neck pain, lower back pain, and general pain. Therefore, further functional improvements are needed in TIP. For example, TIP needs to reduce wear caused by metal-to-metal slippage, reduce surface corrosion, increase cushioning, improve shock absorption, reduce metal debris, and maintain the range of spinal mobility. Summary of the Invention

[0003] This invention addresses the aforementioned problems by providing a treatment solution comprising: the metal sheets of this invention do not slip, thus reducing degradation caused by metal wear; the core design features effectively increase cushioning capacity; the use of special polymeric elastic materials, such as silicone resins or liquid silicone rubber, provides shock absorption capacity, wherein the polymeric elastic materials have different hardness and physical properties; and the effective outer core design, features, and selected materials maintain a range of motion. The overall design of this invention allows it to effectively resist pressure, shear stress, and torsion.

[0004] Further advantages of the present invention will be set forth in the description which follows, or will become apparent from the description, or may be learned by practicing the invention. Further advantages of the invention will also be understood and appreciated by means and combinations thereof particularly set forth in the detailed description of the invention. The detailed description of the invention will specifically illustrate preferred embodiments of the invention. Further advantages and benefits of the embodiments of the invention will become apparent from the following detailed description of the invention and from the related illustrations. Attached Figure Description

[0005] Figure 1 This is a side view of the present invention.

[0006] Figure 2 This is an exploded view of the present invention.

[0007] Figure 3 This is the front view of the present invention.

[0008] Figure 4 This is a rear view of the present invention.

[0009] Figure 5 Includes a top view and a cross-sectional view of the present invention.

[0010] Figure 6 This includes a top view and a front sectional view of one end of the present invention.

[0011] Figure 7 The invention includes a top view, a side sectional view, and a side view of a core component.

[0012] Figure 8 The invention includes a top view, a side sectional view, and a side view of an outer core.

[0013] Figure 9 Includes a top view and a side sectional view, which show an additional embodiment of the invention including anchoring protrusions.

[0014] Figure 10 Includes a top view and a front sectional view, which show an end plate of another embodiment of the invention.

[0015] Figure 11 Includes a top view and a front sectional view, which show an outer core of another embodiment of the invention.

[0016] Figure 12 Includes an exploded perspective view showing a second additional embodiment of the invention.

[0017] Figure 13 Includes a top view and a side sectional view, which show a second additional embodiment of the invention.

[0018] Figure 14 Includes a top view, a side sectional view, and a side view, which show a core of a second additional embodiment of the present invention.

[0019] Figure 15 Includes a top view, a side sectional view, and a side view, which show an outer core of a second additional embodiment of the present invention.

[0020] Figure 16 Includes an exploded perspective view showing a third additional embodiment of the invention.

[0021] Figure 17Includes a top view and a side sectional view, which show an end plate of a third additional embodiment of the present invention.

[0022] Figure 18 Includes a top view, a side sectional view, and a side view, which show a core of a third additional embodiment of the present invention.

[0023] Figure 19 Includes a top view, a side sectional view, and a side view, which show an outer core of a third additional embodiment of the present invention.

[0024] Figure 20 Includes an exploded perspective view showing a fourth additional embodiment of the invention.

[0025] Figure 21 Includes a top view and a side sectional view, which show a fourth additional embodiment of the invention.

[0026] Figure 22 Includes a top view and a side sectional view, which show an end plate of a fourth additional embodiment of the present invention.

[0027] Figure 23 Includes a top view, a side sectional view, and a side view, which show a core of a fourth additional embodiment of the present invention.

[0028] Figure 24 Includes a top view, a side sectional view, and a side view, which show an outer core of a fourth additional embodiment of the present invention. Detailed Implementation

[0029] First and foremost, it should be noted that the illustrations used in this specification are merely for illustrating certain embodiments of the invention, and the scope of the invention is not limited by these illustrations. The invention will be described in detail in a manner that will enable the reader to fully understand it. Many concepts can be implemented or utilized in this invention, and not all features described in this specification are necessarily used. It should be understood that some details have not been described in detail to avoid unnecessarily obscuring the presentation of the focus of the invention. In this specification, terms such as "preferred embodiment," "one embodiment," "some embodiments," or "other embodiments" should be considered as illustrative of the concepts of the invention and not as limiting the scope of the invention.

[0030] This invention relates to a spinal implant for replacing degenerated intervertebral discs. Please refer to... Figures 1 to 5This invention comprises: a first end plate 1, a second end plate 2, a core 3, and an outer core 4. In some embodiments of the invention, each of the first end plate 1, the second end plate 2, the core 3, and the outer core 4 has a nearly circular shape. However, other shapes may be used in this invention, as long as the shape is desired or useful. The core 3 and the outer core 4 are substantially wider than their height and have a thickness or axial height. As mentioned above, in some embodiments, each of the core 3 and the outer core 4 has a circular shape, which is typically a dish shape, and has a circular cross-section in the radial direction. In other embodiments of the invention, the first end plate 1, the second end plate 2, the core 3, and the outer core 4 may have other geometries. Please refer to... Figures 16 to 24 In some embodiments, the first end plate 1, the second end plate 2, the core 3, and the outer core 4 may have generally linear peripheries and rounded corners.

[0031] In a preferred embodiment of the invention, the kernel 3 is located within the outer kernel 4. In some embodiments of the invention, the kernel 3 is concentrically located within the outer kernel 4, wherein the kernel 3 has a kernel centerline 16 and the outer kernel 4 has an outer kernel centerline 17, as shown below. Figure 2 , Figure 5 , Figure 7 , Figure 8 , Figure 12 , Figure 13 ,and Figure 21 As shown. Figure 5 As shown, the core centerline 16 and the outer core centerline 17 overlap, so the core 3 and the outer core 4 are concentric. In some embodiments of the present invention, the core 3 and the outer core 4 are not completely concentric, or are not concentric at all, and the core centerline 16 and the outer core centerline 17 are offset from each other by translation, rotation, or translation plus rotation.

[0032] In a preferred embodiment of the invention, the outer core 4 includes an inner cavity 40 that passes through the outer core 4 centrally. The phrase "the inner cavity 40 passes through the outer core 4 centrally" does not imply that the inner cavity 40 must be concentric with the outer edge of the outer core 4, but simply that the inner cavity 40 passes through the outer core 4 approximately at a central position relative to the outer edge of the outer core 4. In some embodiments of the invention, the inner cavity 40 is concentrically located within the outer core 4; thus, the inner cavity 40 passes through the outer core 4 axially from the center. In some embodiments of the invention, the inner cavity 40 is "non-concentrically" located within the outer core 4. The inner core 3 is located within the inner cavity 40 of the outer core 4, wherein the inner core 3 is enclosed by the outer core 4, the first end plate 1, and the second end plate 2. In some embodiments of the invention, the inner core 3 is concentrically located within the inner cavity 40. In some embodiments of the invention, the shape of the inner edge of the inner cavity 40 is determined by the shape of the outer edge of the outer core 4. In some embodiments of the invention, the core 3 is located "non-concentrically" within the cavity 40.

[0033] In various embodiments of the present invention, the first end plate 1, the second end plate 2, the core 3, and the outer core 4 are arranged concentrically, each of which has a center line; when the first end plate 1, the second end plate 2, the core 3, and the outer core 4 are arranged concentrically, the center lines of the first end plate 1, the second end plate 2, the core 3, and the outer core 4 overlap. In some embodiments of the present invention, one or more of the elements among the first end plate 1, the second end plate 2, the core 3, and the outer core 4 are not concentric with other elements, or are not concentric with other elements at all, wherein the center lines of the one or more elements are offset from each other by translation or rotation; an offset center line may be parallel to one or more center lines of the aforementioned elements by a linear distance; an offset center line may also be offset relative to one or more center lines of the aforementioned elements by an offset angle. In some embodiments of the present invention, the aforementioned center lines may be related to a radial axis, a rotation axis, or a general radial feature of the aforementioned elements.

[0034] In a preferred embodiment of the present invention, the outer core 4 is located between the first end plate 1 and the second end plate 2, and is connected to the first end plate 1 and the second end plate 2. Please refer to... Figures 1 to 11 In some embodiments of the present invention, the outer core 4 is connected to the first end plate 1 and the second end plate 2 by a plurality of interlocking elements 5. In some embodiments of the present invention, the outer core 4 is connected to the first end plate 1 and the second end plate 2 by an adhesive. Figures 12 to 15 and Figures 20 to 24These embodiments are shown. The adhesive described above can be any adhesive suitable for the use of this invention. The adhesive described above needs to be sterile, biodegradable, and biocompatible. The adhesive described above can be, but is not limited to, based on, derived from, or containing the following components: bone bonding agents, polyurethanes, acrylates, rubber, polymers, epoxy resins, phenolic resins, natural adhesives, synthetic adhesives, or any other suitable adhesive substance. Furthermore, the adhesive can also be a product of a manufacturing process rather than a specific adhesive substance.

[0035] The core 3 and the outer core 4 are sandwiched between the first end plate 1 and the second end plate 2, like a sandwich. More specifically, the outer core 4 includes an inner cavity 40 that passes through the center of the outer core 4, and the core 3 is located within the inner cavity 40 of the outer core 4. Thus, the core 3 is sealed by the outer core 4, the first end plate 1, and the second end plate 2.

[0036] In a preferred embodiment of the invention, the core 3 is made of a polymeric material. More specifically, in various embodiments of the invention, the core 3 is made of a medical-grade or transplant-grade polymeric or elastic material, with different materials having different hardness and physical properties in various embodiments. In some embodiments of the invention, the core 3 is made of a liquid silicone rubber material, wherein the liquid silicone rubber material has different hardness and physical properties in various embodiments. In some embodiments of the invention, the core 3 is made of a medical-grade or transplant-grade silicone rubber elastic material, wherein the rubber elastic material has a Shore A hardness of 60 to 90. In some embodiments of the invention, the core 3 is made of a liquid silicone rubber material (LSR), which is widely used in breast augmentation surgery. Silicone rubber materials can maintain their shape and mechanical strength under high pressure, high shear stress, high torsion, high tension, and high flexural conditions, and have good anti-creep properties. In other embodiments of the invention, other suitable materials can also be used to manufacture the core 3. In this invention, the core 3 serves as a baffle and buffer to withstand and resist localized pressure, shear stress, torsion, and other stresses. In various embodiments of the invention, the core 3 has a diameter ranging from 0.125 inches to 2.25 inches. However, it should be understood that the invention can have various dimensional variations without departing from the spirit and scope of the invention.

[0037] Please refer to Figure 5 and Figure 7In a preferred embodiment of the invention, the core 3 further includes a first core protrusion 30 and a second core protrusion 31. The first core protrusion 30 and the second core protrusion 31 are opposite to each other along the core centerline 16, separated by the thickness of the core 3. In some embodiments of the invention, the first core protrusion 30 and the second core protrusion 31 are axially opposite to each other, separated by the thickness of the core 3, wherein the first core protrusion 30 and the second core protrusion 31 are concentric with each other along the core centerline 16. In other embodiments of the invention, the centers of the first core protrusion 30 and the second core protrusion 31 are offset from the core centerline 16 and are not concentric with the core centerline 16.

[0038] The first core protrusion 30 and the second core protrusion 31 are essentially protrusions located in the middle of the core. After the present invention is implanted into the human spine, the first core protrusion 30 and the second core protrusion 31 contribute to enabling the core 3 to withstand and resist stress. The first core protrusion 30 and the second core protrusion 31 correspond to and mate with the recesses of the first end plate 1 and the second end plate 2. This part will be described in more detail later. In various embodiments of the present invention, the protrusion angle of the first core protrusion 30 and the second core protrusion 31 is between 5 degrees and 60 degrees; the outer diameter of the first core protrusion 30 and the second core protrusion 31 is between 0.075 inches and 2 inches. In some embodiments of the present invention, the core 3 further includes a sidewall with a protruding curvature. In various embodiments of the present invention, the sidewall radius is between 0.063 inches and 2.25 inches. However, it should be understood that the present invention can have various dimensional variations without departing from the spirit and scope of the invention.

[0039] As previously described, in some embodiments of the present invention, the core 3 has a core centerline 16, and the outer core 4 has an outer core centerline 17. In some embodiments of the present invention, the core centerline 16 and the outer core centerline 17 can be considered as axes equidistant from the outer peripheries of the core 3 and the outer core 4, and / or axes of rotation of radial features. In some embodiments of the present invention, the radial axis can be considered as an axis of rotation and is different from the core centerline 16 of the core 3 and the outer core centerline 17 of the outer core 4. In some embodiments of the present invention, the radial axis can be offset from the core centerline 16 and the outer core centerline 17. In these embodiments, the first core protrusion 30 and the second core protrusion 31 are concentric with the radial axis of the core 3. Furthermore, in these embodiments, the inner cavity 40 of the outer core 4 is concentric with the radial axis of the outer core 4. In other embodiments of the present invention, the first core protrusion 30 and the second core protrusion 31 are not concentric with the radial axis of the core 3; the inner cavity 40 of the outer core 4 is not concentric with the radial axis of the outer core 4.

[0040] The outer core 4 serves as a sealing ring for the inner core 3; after the invention is implanted in the human body, the outer core 4 provides appropriate mobility to the spine. In a preferred embodiment of the invention, the outer core 4 is composed of a polymeric material or an elastic material, wherein these polymeric materials or elastic materials have different hardness and physical properties in different embodiments.

[0041] In various embodiments, the outer core 4 can be made of various different materials. In a preferred embodiment of the invention, the outer core 4 is made of a polymeric material. In some embodiments of the invention, the outer core 4 is made of a liquid silicone rubber material, wherein the liquid silicone rubber material has different hardness in different embodiments. In some embodiments of the invention, the outer core 4 is made of ultra-high molecular weight polyethylene (UHMWPE). In some embodiments of the invention, the outer core 4 is made of medical-grade polypropylene (PP). However, in different embodiments of the invention, the material of the outer core 4 can also be varied as needed. Generally, the material of the outer core 4 needs to have: high abrasion resistance, high corrosion resistance, high strength, light weight, and low coefficient of friction. In various embodiments of the invention, the diameter of the outer core 4 ranges from 0.175 inches to 2.375 inches. However, as mentioned above, the dimensions of the various components mentioned in this specification are not intended to limit the scope of the invention, and the dimensions of the various components can be varied and modified in different embodiments.

[0042] In a preferred embodiment of the present invention, the first endplate 1 and the second endplate 2 are made of a polyetheretherketone (PEEK) material. However, in various embodiments, the first endplate 1 and the second endplate 2 can be made of various different materials. The use of PEEK materials is gradually increasing in fields such as tumor therapeutic biomaterials, orthopedic surgery, and spinal implants. PEEK materials possess high strength, inertness, and biocompatibility. The following properties make PEEK a preferred material for endplates: a bone-like elastic modulus, low stress shielding effect, artifact-free image quality, and a surface suitable for bone regeneration. Furthermore, PEEK materials can be used in conjunction with titanium materials. Moreover, PEEK materials can be used in conjunction with titanium metal soldered onto the surface of the outer core 4. The outer surfaces of the first endplate 1 and the second endplate 2 can be treated with a titanium metal material.

[0043] Reference Figures 1 to 6In a preferred embodiment of the invention, each of the first end plate 1 and the second end plate 2 further comprises: a plate body 20, an inner surface 21, an outer surface 22, a plate protrusion 23, and a plate recess 24, wherein the distance from the inner surface 21 to the outer surface 22 is the thickness of the plate body 20. In various embodiments of the invention, the diameter of the plate body 20 ranges from 0.375 inches to 2.5 inches; the thickness of the plate body 20 ranges from 0.031 inches to 0.375 inches. However, it should be understood that the invention can have various dimensional variations without departing from the spirit and scope of the invention.

[0044] In a preferred embodiment of the present invention, the plate body 20 of the first end plate 1 and the plate body 20 of the second end plate 2 are sandwiched at a specific inclination angle 6, such as... Figure 1 As shown. A specific tilt angle 6 defines the degree to which the plates 20 of the first endplate 1 and the second endplate 2 deviate from a parallel state. Different embodiments may have different tilt angles 6, primarily depending on the intervertebral disc to be replaced. In various embodiments of the invention, the specific tilt angle 6 ranges between 0.5 degrees and 15 degrees. In some embodiments of the invention, the specific tilt angle 6 is less than 0.5 degrees. In some embodiments of the invention, the specific tilt angle 6 is 0 degrees, such that the plates 20 of the first endplate 1 and the second endplate 2 are parallel to each other. In some embodiments of the invention, the specific tilt angle 6 is greater than 15 degrees.

[0045] Two plate protrusions 23 are located at the central portions of the outer surfaces 22 of the plate bodies 20 of the first end plate 1 and the second end plate 2, respectively. Two plate recesses 24 are located at the central portions of the inner surfaces 21 of the plate bodies 20 of the first end plate 1 and the second end plate 2, respectively. In some embodiments of the invention, the thickness of the plate body 20 is fixed; by partially displacing the substantially flat plate body 20 to form the plate protrusions 23 and plate recesses 24, the end plate thickness of the plate protrusions 23 and plate recesses 24 is equal to the end plate thickness at their periphery. In other embodiments of the invention, the plate protrusions 23 and plate recesses 24 of the first end plate 1 are formed independently of each other, and the plate protrusions 23 and plate recesses 24 of the second end plate 2 are also formed independently of each other. In some embodiments of the invention, a rounded corner is formed between the plate body 20 and the plate protrusions 23; the radius of this rounded corner may be, but is not limited to, between 0.015 inches and 0.5 inches. The fillet is used to reduce any stress caused by the local pressure applied to the first end plate 1 and the second end plate 2. The first core protrusion 30 is located within the plate recess 24 of the first end plate 1; the second core protrusion 31 is located within the plate recess 24 of the second end plate 2.

[0046] As previously described, in some embodiments of the present invention, the outer core 4 is connected to the first end plate 1 and the second end plate 2 by a plurality of interlocking elements 5. In some embodiments of the present invention, the inner core 3 is also connected to the first end plate 1 and the second end plate 2 by a plurality of interlocking elements 5, although this is not necessarily required. More specifically, the inner surface 21 of the first end plate 1 is connected to the outer core 4 by a plurality of interlocking elements 5; the inner surface 21 of the second end plate 2 is connected to the outer core 4 by a plurality of interlocking elements 5, and is axially separated from the first end plate 1 by the inner core 3.

[0047] Please refer to Figures 1 to 6 In some embodiments of the invention, each of the first end plate 1 and the second end plate 2 further includes: an attachment flange 25 and at least one fastening hole 26. The attachment flange 25 secures the invention to an adjacent vertebra by one or more implantation screws. In various embodiments of the invention, the contents of the attachment flange 25 depend on the requirements of the final product. The attachment flange 25 is vertically connected to the edge of the plate body 20; in each of the first end plate 1 and the second end plate 2, the attachment flange 25 extends from the inner surface 21 beyond the outer surface 22, wherein the attachment flange 25 is connected to the plate body 20 along an arcuate segment along the outer edge of the plate body 20. Preferably, the attachment flange 25 does not extend beyond the inner surface 21, but this may vary in different embodiments. At least one fastening hole 26 passes through the attachment flange 25 of each of the first end plate 1 and the second end plate 2. In different embodiments, each of the at least one fastener hole 26 may be a bore, a countersunk hole, a through hole, or other various holes that can accept different fasteners.

[0048] Furthermore, in some embodiments of the invention, the mounting flange 25 includes an inner groove 27. The inner groove 27 extends radially into the mounting flange 25 in both the first end plate 1 and the second end plate 2, and advances along an arcuate flange segment adjacent to the outer surface 22 of the plate body 20, while also advancing along the outer periphery adjacent to the plate body 20. When performing total artificial disc replacement to reduce friction at any vertebral edge, the inner groove 27 serves to provide clearance to adjacent vertebral edges.

[0049] Please refer to Figure 2 and Figures 5 to 7In a preferred embodiment of the invention, the outer core 4 further includes a plurality of first core interlocking elements 50 and a plurality of second core interlocking elements 51 among the interlocking elements 5, wherein the plurality of first core interlocking elements 50 and the plurality of second core interlocking elements 51 are opposite to each other across the thickness of the outer core 4. In some embodiments of the invention, the plurality of first core interlocking elements 50 and the plurality of second core interlocking elements 51 are axially opposite to each other across the thickness of the outer core 4. Furthermore, each of the first end plate 1 and the second end plate 2 further includes a plurality of plate interlocking elements 52 among the interlocking elements 5. The plurality of plate interlocking elements 52 are concentrically distributed along the plate recesses 24 of the inner surface 21 of the plate body 20 of the first end plate 1 and the second end plate 2. A plurality of first core interlocking elements 50 of the outer core 4 are coupled to a plurality of plate interlocking elements 52 of the first end plate 1; a plurality of second core interlocking elements 51 of the outer core 4 are coupled to a plurality of plate interlocking elements 52 of the second end plate 2.

[0050] Please refer to Figure 2 , Figure 5 , Figure 6 and Figures 8 to 11 Furthermore, in some embodiments, the invention further includes a plurality of interlocking element receiving slots 7. Each of the plurality of interlocking element receiving slots 7 is adjacent to and concentric with one of the plurality of interlocking elements 5; each of the plurality of interlocking elements 5 is located within one of the plurality of interlocking element receiving slots 7. When the outer core 4 and the inner core 3 are subjected to external force, the plurality of interlocking elements 5 and the plurality of interlocking element receiving slots 7 are designed to prevent the outer core 4 and the inner core 3 from being squeezed and protruding. The plurality of interlocking elements 5 and the plurality of interlocking element receiving slots 7 may have different shapes and configurations in different embodiments. For example, in some embodiments of the invention, the plurality of interlocking elements 5 and the plurality of interlocking element receiving slots 7 have a wedge-shaped tenon joint mechanism, such as... Figure 2 and Figures 5 to 8 As shown, as the direction moves further away from the center of the outer core 4, the cross-sectional width of each of the plurality of interlocking elements 5 gradually increases, while the shape of each of the plurality of interlocking element receiving slots 7 is opposite to that of the plurality of interlocking elements 5 to receive the interlocking element 5. In some embodiments of the invention, the cross-sectional shape of each of the plurality of interlocking elements 5 is similar to that of a tooth, having an angular protrusion and a rounded root, wherein the cross-sectional shape of the interlocking element receiving slot 7 is opposite to that of the plurality of interlocking elements 5 to receive the interlocking element 5. In the above two examples, the distal end of the interlocking element 5 has a larger width compared to the rest of the interlocking element 5, so that the interlocking element 5 can be fixed within the interlocking element receiving slot 7. In some embodiments of the invention, the widths of the interlocking elements 5 and the interlocking element receiving slots 7 do not change, such as Figure 9 As shown.

[0051] Please refer to Figures 9 to 11In some embodiments of the invention, each of the plurality of interlocking elements 5 is oriented at a specific anti-protrusion angle 53 to resist the protrusion of the core 3 and / or the outer core 4 as described above. More specifically, in these embodiments, each of the plurality of first core interlocking elements 50, the plurality of second core interlocking elements 51, and the plurality of plate interlocking elements 52 is oriented toward this specific anti-protrusion angle 53. This specific anti-protrusion angle 53 can be defined in various ways. However, here this specific anti-protrusion angle 53 is defined in relation to the central axis 15. The central axis 15 can be considered as an axis around which the radial features of the invention are concentrically distributed, for example, but not limited to: the core 3, the outer core 4, and the plate 20. For the core 3, the outer core 4, and the plate 20, their individual central axes can be further appropriately defined to correspond to the angular differences caused by a specific tilt angle 6. In various embodiments of the invention, the core centerline 16 and the outer core centerline 17 discussed above can be the same as or different from the central axis 15.

[0052] It is important to understand that, due to the specific tilt angle 6, the individual central axes of the plate 20, the core 3, and / or the outer core 4 may not overlap. However, for convenience, their individual central axes are assumed to overlap here.

[0053] It is important to determine here that the specific anti-protrusion angle 53 should be radially outward from the central axis, through which an imaginary straight line can extend outward from any known number of first core interlocking elements 50 or any known number of second core interlocking elements 51 without intersecting the central axis. This is important because an inward anti-protrusion angle 53 may or may not provide the same effective interlocking effect as an outward anti-protrusion angle 53.

[0054] As previously described, the primary function of the plurality of interlocking elements 5 and the plurality of interlocking element receiving slots 7 is to fix the core 3 to the first end plate 1 and the second end plate 2. A secondary function is to counteract the protrusion of the outer core 4 (and in some embodiments, the core 3) when the invention is subjected to external forces (especially pressure). When the invention is subjected to an axial pressure, the core 3 and the outer core 4 tend to undergo a certain degree of compressive deformation axially and a certain degree of expansion deformation laterally. Therefore, the following becomes a concern: when the invention is subjected to these external forces, a portion of the core 3 and the outer core 4 may protrude from their originally designed position, potentially causing misalignment or damage. The plurality of interlocking element receiving slots 7 can provide some space to accommodate such protrusions. Furthermore, the physical interlocking between the plurality of interlocking elements 5 and the plurality of interlocking element receiving slots 7 can prevent displacement of the core 3 and the outer core 4 relative to the first end plate 1 and the second end plate 2. The plurality of interlocking elements 5 and the plurality of interlocking element receiving slots 7 can have different numbers in different embodiments, for example, from one to nine. However, the present invention includes any number of interlocking elements 5 and interlocking element receiving slots 7.

[0055] As previously described, in various embodiments of the invention, the first endplate 1 and the second endplate 2 are opposed to each other at a specific tilt angle 6 to mimic the shape of an intervertebral disc to be replaced by the invention. The plate body 20 of the first endplate 1, the plate body 20 of the second endplate 2, the inner core 3, and the outer core 4 can be understood as extending longitudinally between a proximal end 8 and a distal end 9. For the plate body 20 of the first endplate 1, the plate body 20 of the second endplate 2, the inner core 3, and the outer core 4, the proximal end 8 and the distal end 9 are opposed to each other in the diametrical direction. For each of the plate body 20 of the first endplate 1, the plate body 20 of the second endplate 2, the inner core 3, and the outer core 4, their proximal ends 8 are defined herein as radially aligned with each other, and their distal ends 9 are also defined herein as radially aligned with each other. Thus, in some embodiments of the invention, the specific tilt angle 6 is defined on a plane overlapping with the proximal ends 8 and 9. In some embodiments of the invention with an attachment flange, the attachment flange is located at the proximal end 8 of each of the first end plate 1 and the second end plate 2. In various embodiments of the invention, a specific tilt angle 6 may have different orientations and arrangements. However, the invention is not limited to the various descriptions above.

[0056] Please refer to Figure 7 and Figure 8Furthermore, in some embodiments of the present invention, a specific tilt angle 6 can be achieved by varying the radial thickness of the core 3 and the outer core 4. Thus, the axial outer ends of the core 3 and the outer core 4 are opposite each other at a specific tilt angle 6. Consequently, the essentially planar first end plate 1 and the second end plate 2 are also opposite each other at a specific tilt angle 6. Therefore, the proximal thickness 10 and distal thickness 11 of the core 3 and the outer core 4 can be defined as follows: the proximal thickness 10 of the outer core is the thickness of the outer core 4 at its proximal end 8; the distal thickness 11 of the outer core is the thickness of the outer core 4 at its distal end 9; the proximal thickness 10 of the core is the thickness of the core 3 at its proximal end 8; and the distal thickness 11 of the core is the thickness of the core 3 at its distal end 9.

[0057] Therefore, in some embodiments of the present invention, the proximal thickness 10 of the core 3 is greater than the distal thickness 11 of the core 3; the proximal thickness 10 of the outer core 4 is greater than the distal thickness 11 of the outer core 4. Thus, in some embodiments of the present invention, a specific tilt angle 6 can be determined by the thickness difference between the proximal thickness 10 and the distal thickness 11. In some embodiments of the present invention, the specific tilt angle 6 can be determined by other means. For example, the thicknesses of the core 3 and the outer core 4 are fixed, while the thicknesses of the first end plate 1 and the second end plate 2 vary.

[0058] Please refer to Figure 9 In some embodiments of the invention, as an alternative to the mounting flange 25, the first end plate 1, and the second end plate 2, the invention further includes a plurality of anchoring protrusions 12. The plurality of anchoring protrusions 12 serve as an alternative to mounting the first end plate 1 and the second end plate 2 to an adjacent vertebra. The anchoring protrusions 12 are connected to the outer surface 22 and are preferably perpendicular to the plate body 20. The anchoring protrusions 12 can be distributed on the outer surface 22 in any manner. For example, four anchoring protrusions 12 are distributed at 90-degree intervals on the plate protrusions 23. However, the invention is not limited to this embodiment. Furthermore, each anchoring protrusion 12 may include a plurality of teeth 13 located at a distal end 14 of the anchoring protrusion 12.

[0059] The components of this invention can be manufactured using various suitable manufacturing methods; these methods may include, but are not limited to, 3D printing, CNC machining, injection molding, compression molding, or other suitable methods. Preferably, the core 3 is injection molded using an insert injection molding method, wherein the first end plate 1 and the second end plate 2 are used as inserts. In other embodiments of this invention, the core 3 can be manufactured independently using 3D printing, injection molding, or compression molding, and then combined with the first end plate 1 and the second end plate 2. Preferably, the outer core 4 can be manufactured using injection molding, compression molding, or insert injection molding, wherein the combination of the first end plate 1, the second end plate 2, and the core 3 can be used as an insert in the insert injection molding method. In other embodiments of this invention, the outer core 4 can be manufactured independently using 3D printing, injection molding, or compression molding, and then combined with the first end plate 1, the second end plate 2, and the core 3. Furthermore, in a preferred embodiment of the present invention, at each stage of assembling the elements of the present invention, the various elements are surface treated to increase covalent bonding strength, cohesion, and / or adhesion.

[0060] Please refer to Figures 12 to 15 These illustrations show a second, alternative embodiment of the invention, in which the inner cavity 40 of the outer core 4 is not concentric with the outer core centerline 17; the first core protrusion 30 and the second core protrusion 31 of the inner core 3 are not concentric with the core centerline 16. Furthermore, the core centerline 16 and the outer core centerline 17 are offset from each other. Such a geometric arrangement has various advantages in different applications, for example, it helps to conform to the patient's spine. In this second, alternative embodiment, the adhesive previously discussed is further used to bond the outer core 4 to the first endplate 1 and the second endplate 2.

[0061] Please refer to Figures 16 to 19 These illustrations show a third, additional embodiment of the invention, in which the geometry surrounding the core 3 and outer core 4 is generally linear. Such a geometric arrangement has various advantages in different use cases or implantation scenarios, such as facilitating the insertion of the invention into a patient's spine.

[0062] Please refer to Figures 20 to 24 These figures illustrate a fourth embodiment of the invention, wherein the geometry surrounding the core 3 and the outer core 4 is generally linear, as in the third embodiment; however, the outer core 4 is bonded to the first end plate 1 and the second end plate 2 by adhesive, as in the second embodiment. Various embodiments of the invention include combinations of the features described above, which may more or less facilitate use in various situations, and therefore are not intended to strictly limit the invention to certain specific embodiments.

[0063] The present invention has been described above with reference to embodiments. However, it should be understood that any modifications or variations made to these embodiments without departing from the spirit or scope of the present invention are still included within the scope of the present invention.

Claims

1. A motion preserving spinal implant for total disc replacement, comprising: a first endplate (1); wherein the first endplate (1) comprises a plate body (20), a plate convexity (23) and a plate concavity (24), the plate convexity (23) and the plate concavity (24) are disposed on the plate body (20); wherein the plate body (20) of the first endplate (1) further comprises an inner side (21) and an outer side (22); wherein the plate convexity (23) is located at the central position of the outer side (22) of the first endplate (1); wherein the plate concavity (24) is located at the central position of the inner side (21) of the first endplate (1); wherein the convexity of the plate convexity (23) is equal to the concavity of the plate concavity (24); a second endplate (2); wherein the second endplate (2) comprises a plate body (20), a plate convexity (23) and a plate concavity (24), the plate convexity (23) and the plate concavity (24) are disposed on the plate body (20); wherein the plate body (20) of the second endplate (2) further comprises an inner side (21) and an outer side (22); wherein the plate convexity (23) is located at the central position of the outer side (22) of the second endplate (2); wherein the plate concavity (24) is located at the central position of the inner side (21) of the second endplate (2); wherein the convexity of the plate convexity (23) is equal to the concavity of the plate concavity (24); an outer core (4), the outer core (4) has a main body and an inner cavity (40) through the outer core (4); wherein the outer core (4) is disposed between the first endplate (1) and the second endplate (2); wherein the core interlocking components disposed on the main body of the outer core (4) are engaged with the plate interlocking components (52) disposed on the inner side (21) of the first endplate (1); wherein the core interlocking components disposed on the main body of the outer core (4) are engaged with the plate interlocking components (52) disposed on the inner side (21) of the second endplate (2); an inner core (3), the inner core (3) comprises a first core convexity (30) and a second core convexity (31), the first core convexity (30) and the second core convexity (31) are oppositely disposed along the thickness of the inner core (3); wherein the inner core (3) is disposed in the inner cavity (40), so that the first core convexity (30) is located in the plate concavity (24) of the first endplate (1), and the second core convexity (31) is located in the plate concavity (24) of the second endplate (2); wherein the inner core (3) is sealed by the outer core (4), the first endplate (1) and the second endplate (2); wherein the plate body (20) of the first endplate (1) and the plate body (20) of the second endplate (2) are oriented to each other at a specific oblique angle; wherein the specific oblique angle defines that the plate body (20) of the first endplate (1) and the plate body (20) of the second endplate (2) deviate from the direction parallel to each other.

2. The motion preserving spinal implant for total disc replacement of claim 1 wherein: the inner cavity extends through the outer core along a central axis of the outer core; the inner core is centrally located within the inner cavity.

3. The motion preserving spinal implant for total disc replacement according to claim 1 wherein, the first endplate, the second endplate, the inner core, and the outer core each have a straight perimeter geometry.

4. The motion preserving spinal implant for total disc replacement of claim 1 wherein: the inner core and the outer core each include a radial axis and a central axis; for the inner core and the outer core, the radial axis is offset from the central axis; the first core protrusion and the second core protrusion of the inner core are concentrically positioned about the radial axis of the inner core.

5. The motion preserving spinal implant for total disc replacement of Claim 1 wherein, the outer core is attached between the first endplate and the second endplate by an adhesive.

6. The motion preserving spinal implant for total disc replacement of Claim 1 wherein, the specific angle of inclination is in the range of 0 degrees to 15 degrees.

7. The motion preserving spinal implant for total disc replacement of Claim 1 wherein, the inner core is made of a polymeric material.

8. The motion preserving spinal implant for total disc replacement of Claim 1 wherein, the first endplate and the second endplate are made of a polyether ether ketone (PEEK) material.

9. The motion preserving spinal implant for total disc replacement of Claim 1 wherein, the inner core is made of a liquid silicone rubber having different durometers.

10. The motion preserving spinal implant for total disc replacement of Claim 1 wherein, the outer core is made of a liquid silicone rubber having different durometers.

11. The motion preserving spinal implant for total disc replacement of Claim 1 wherein, the outer core is made of a polymer.

12. The motion preserving spinal implant for total disc replacement of claim 1 wherein: the first endplate and the second endplate each further include an attachment flange and at least one fastener hole; the attachment flange is perpendicularly and circumferentially attached to the plate body and extends outwardly from the inner side beyond the outer side, the attachment flange includes a flange arc segment disposed along the plate body perimeter for the first endplate and the second endplate; at least one fastener hole extends through the attachment flange of the first endplate and the second endplate.

13. The motion preserving spinal implant for total disc replacement of claim 12 wherein: the attachment flange includes an inner groove; the inner groove extends circumferentially through the attachment flange along the flange arc segment proximate the outer side and proximate the plate body for the first endplate and the second endplate.

14. The motion preserving spinal implant for total disc replacement of claim 1 wherein: the outer core includes a first set of core interlocking members and a second set of core interlocking members from a plurality of core interlocking members, wherein the first set of core interlocking members and the second set of core interlocking members are oppositely disposed along a thickness of the outer core; the plurality of plate interlocking members are concentrically disposed about the plate recess of the inner side of the plate body for the first endplate and the second endplate; the first set of core interlocking members of the outer core is engaged with the plurality of plate interlocking members of the first endplate; the second set of core interlocking members of the outer core is engaged with the plurality of plate interlocking members of the second endplate.

15. The motion preserving spinal implant for total disc replacement of claim 14 wherein, includes: a plurality of interlocking member receiving channels; each of the interlocking member receiving channels is concentrically and adjacently disposed with one of the core interlocking members and the plate interlocking members; Each of the core interlocking members and the plate interlocking members is located within one of the plurality of interlocking member receiving channels, wherein the plurality of core interlocking members and plate interlocking members and the plurality of interlocking member receiving channels are configured to resist extrusion of the inner core and the outer core when the inner core and the outer core receive an external force.

16. The motion preserving spinal implant for total disc replacement of claim 1 wherein: the plate body of the first end plate, the plate body of the second end plate, the inner core, and the outer core each extend longitudinally between a proximal end and a distal end, wherein for the plate body, the inner core, and the outer core, the proximal end and the distal end are opposite each other; the proximal ends of the plate body of the first end plate, the plate body of the second end plate, the inner core, and the outer core are radially aligned with each other, and the distal ends of the plate body of the first end plate, the plate body of the second end plate, the inner core, and the outer core are radially aligned with each other, and the particular oblique angle is defined in a plane that coincides with the proximal ends and the distal ends.

17. The motion preserving spinal implant for total disc replacement of claim 16 wherein: the first end plate and the second end plate each further comprise a connecting flange; the connecting flange is located at the proximal end of the first end plate and the second end plate.

18. The motion preserving spinal implant for total disc replacement of claim 16 wherein: the inner core has a greater thickness at the proximal end than at the distal end; the outer core has a greater thickness at the proximal end than at the distal end, wherein the particular oblique angle is determined by the difference between the thickness at the proximal end and the thickness at the distal end.

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