Piezoelectric spinal implants and methods of making and using same

Abstract

A spinal implant capable of generating an electrical output includes a first end plate, a second end plate, and a piezoelectric element disposed between the first end plate and the second end plate. The spinal implant may also include an intermediate body and a second piezoelectric element disposed between the intermediate body and the second end plate. The inner surface of the end plate and / or the intermediate body may be non-planar, for example, having a wave shape. When the end plate of the spinal implant is stressed (including compressive force and / or shear force), electrical output is generated.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 335,343, filed on April 27, 2022, which is hereby incorporated by reference in its entirety. Technical Field

[0003] The present application relates to spinal implants that include piezoelectric materials capable of stimulating bone and tissue growth around the implant. Specifically, the present application relates to a spinal implant having piezoelectric properties that can generate an electrical charge on its surface, thereby enhancing bone growth around the cage. The electrical output from the piezoelectric material can be generated by fluctuations in an applied mechanical load. Background Art

[0004] Electrical stimulation has long been used to stimulate bone growth and promote fusion after spinal implant surgery. If, after a period of recovery, the patient does not naturally produce the type of growth their physicians anticipate, a second surgery may be necessary to place an electrical implant and associated battery under the skin with the cathode extending into the fusion area around the bone. Because of its invasive nature and the need for additional surgery, this type of treatment is typically used only as an adjunct to stimulating bone growth.

[0005] Alternatively, patients may be instructed to wear a noninvasive vest or harness, or to use small skin pads / electrodes that generate a weak electrical current in the target's line of sight using pulsed electromagnetic fields, capacitive coupling, or combined magnetic fields. However, data demonstrating the effectiveness of this type of noninvasive treatment are limited. Summary of the invention

[0006] According to one embodiment of the present invention, a spinal implant capable of generating an electrical output includes a first end plate having an inner surface, a second end plate having an inner surface, and a first piezoelectric element disposed between the inner surfaces of the first end plate and the second end plate. When a force is applied to the first and second end plates, the piezoelectric element has a non-planar shape.

[0007] In one embodiment, the inner surfaces of the first and second end plates can be non-planar. For example, they can be wavy. The piezoelectric element can have an upper surface that conforms to the inner surface of the first end plate and a lower surface that conforms to the inner surface of the second end plate. The force can be an assembly force and / or the force can be a spinal compression force. The force can be between 25N and 10000N.

[0008] According to another embodiment, the spinal implant may further include a second piezoelectric element disposed between the first end plate and the second end plate, and an intermediate body having a non-planar top surface and a non-planar bottom surface disposed between the first piezoelectric element and the second piezoelectric element.

[0009] According to a related embodiment, the first piezoelectric element has an upper surface that conforms to the inner surface of the first end plate and a lower surface that conforms to the top surface of the intermediate body. The second piezoelectric element may have an upper surface that conforms to the bottom surface of the intermediate body and a lower surface that conforms to the inner surface of the second end plate.

[0010] In a related embodiment, the intermediate body can be an insulator. The first and second end plates can be conductive and further include a plurality of conductive jumpers disposed through the intermediate body. One end of each jumper can be connected to a surface of the piezoelectric element and the other end of each jumper can be flush with an outer surface of the intermediate body.

[0011] In a related embodiment, the spinal implant can include at least one connecting element secured to the first and second end plates, the connecting element acting as an insulator, wherein the intermediate body acts as a conductor.

[0012] In one or more embodiments, the first and second end plates have a non-uniform outer surface texture. One or more piezoelectric elements may include a plurality of different layers, at least one of which is a piezoelectric layer. At least one non-piezoelectric layer may also be present.

[0013] According to one embodiment, the first and second end plates have outer surfaces, and the piezoelectric element is configured to generate an electrical output corresponding to a load applied to the outer surfaces of the first and second end plates.

[0014]

[0013] Embodiments of methods of using a spinal implant may include attaching a first endplate to a first vertebra and attaching a second endplate to a second vertebra.

[0015] An embodiment of a spinal implant capable of generating an electrical output includes a first endplate having a non-planar inner surface, a second endplate having a non-planar inner surface, and a first piezoelectric element disposed between the inner surfaces of the first and second endplates.

[0016] Another embodiment of a spinal implant capable of generating an electrical output includes a first end plate having an inner surface, a second end plate having an inner surface, a first piezoelectric element disposed between the inner surfaces of the first end plate and the second end plate, and an intermediate body having a structural geometry that unevenly distributes a compressive force applied to the end plate to the piezoelectric material. In related embodiments, the structural geometry can be a change in material stiffness and / or material shape. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Further embodiments of the present application can be understood with reference to the accompanying drawings.

[0018] Figure 1 is a side view of a piezoelectric spinal implant disposed between two vertebrae of a spine in accordance with an embodiment of the present invention.

[0019] Figure 2a is a front perspective view of one embodiment of a piezoelectric spinal implant, wherein the layers are depicted as top and bottom end plates for anchoring the implant to opposing bone surfaces, a piezoelectric element (e.g., PVDF) that can generate an electrical output when loaded or strained, and an intermediate layer that can be made of a conductive or insulating material; Figure 2b yes Figure 2a A partially transparent side view of an embodiment of showing a lag screw used to assemble an implant and without applying a shielding force in a compressive direction; Figure 2c yes Figure 2a A side view of an embodiment of the present invention; Figure 2d yes Figure 2c a detailed view of a portion of; Figure 2e yes Figure 2a A partially transparent front view of an embodiment of Figure 2f yes Figure 2a A partially transparent top perspective view of an embodiment of; and Figure 2g to Figure 2i yes Figure 2a Side, front and top perspective exploded views of an embodiment of.

[0020] Figures 3a to 3f are a top perspective view, a top view, a side view, a partially transparent top perspective view, a bottom view, and a partially transparent side view of another embodiment of a piezoelectric spinal implant.

[0021] Figure 4a to Figure 4b are a top perspective view and a partially transparent top perspective view of another embodiment of a piezoelectric spinal implant.

[0022] Figure 5a to Figure 5c is a side, partially transparent front and side perspective view of another embodiment of a piezoelectric spinal implant.

[0023] Figure 6a to Figure 6b are top and side perspective views of another embodiment of a piezoelectric spinal implant.

[0024] Figure 7a to Figure 7b is a side perspective view of another embodiment of a piezoelectric spinal implant.

[0025] Figure 8a to Figure 8b is a side perspective view of another embodiment of a piezoelectric spinal implant.

[0026] Figure 9a to Figure 9b are top and bottom perspective views of another embodiment of a piezoelectric spinal implant.

[0027] Figures 10a to 10c 2 is a side perspective view and detail view of another embodiment of a piezoelectric spinal implant.

[0028] Figure 11a to Figure 11bis a side perspective view of another embodiment of a piezoelectric spinal implant.

[0029] Fig.12 is a top perspective view of another embodiment of a piezoelectric spinal implant.

[0030] Figures 13a to 13c are side perspective and side views of another embodiment of a piezoelectric spinal implant.

[0031] Figure 14a to Figure 14b is a side perspective and exploded view of another embodiment of a piezoelectric spinal implant.

[0032] Figures 15a to 15c 2 is a side perspective view and a top detailed view of another embodiment of a piezoelectric spinal implant.

[0033] Figures 16a to 16d are front and side perspective views of another embodiment of a piezoelectric spinal implant.

[0034] Figure 17a to Figure 17b is a right side and side perspective view of another embodiment of a piezoelectric spinal implant.

[0035] Fig.18 is a right side perspective view of another embodiment of a piezoelectric spinal implant.

[0036] Figures 19a to 19f are right side view, top perspective view, and side perspective view of another embodiment of a piezoelectric spinal implant.

[0037] Figures 20a to 20c are partially transparent rear perspective, top perspective, and rear perspective views of another embodiment of a piezoelectric spinal implant.

[0038] Fig.21 is a front perspective view of another embodiment of a piezoelectric spinal implant.

[0039] Figures 22a to 22d are front, side, and top perspective views of another embodiment of a piezoelectric spinal implant.

[0040] Fig.23 is a schematic diagram of a testing apparatus according to an embodiment of the present invention that uses a force vibrator to replicate the forces applied to an implant by a user while walking.

[0041] Figure 24 to Figure 29 is a graphical representation of the current and voltage produced by an implant at vibration powers of 10, 15, and 20 V at a frequency of 2 Hz in accordance with an embodiment of the present invention.

[0042] Fig.30 is a graphical representation of current generated by an implant under different forces according to an embodiment of the present invention.

[0043] Fig.31 is an exploded view of a "3-piece" piezoelectric spinal implant according to an embodiment of the present invention.

[0044] Fig.32a and Figure 32b 2 are assembled and exploded views of a "2-piece" piezoelectric spinal implant according to an embodiment of the present invention.

[0045] Fig.33a , Figure 33b and Fig.33c are views of a piezoelectric spinal implant with piezoelectric elements in different orientations according to an embodiment of the present invention.

[0046] Fig.34a and Fig.34b is an exploded view of a piezoelectric spinal implant having a piezoelectric element composed of one or more layers in accordance with an embodiment of the present invention.

[0047] Fig.35 is an exploded view of another embodiment of a "3-piece" piezoelectric spinal implant according to an embodiment of the present invention.

[0048] Fig.36a and Fig.36b A piezoelectric spinal implant under compressive and shear loads is shown in accordance with an embodiment of the present invention.

[0049] Fig.37a , Fig.37b and Fig.37c A piezoelectric spinal implant having piezoelectric elements in different orientations producing different electric fields is shown in accordance with an embodiment of the present invention.

[0050] Fig.38 A piezoelectric spinal implant having a wound or folded piezoelectric element according to an embodiment of the present invention.

[0051] Fig.39a and Fig.39b A selectively conductive piezoelectric element and its arrangement in a spinal implant for generating an electric field according to an embodiment of the present invention are shown.

[0052] Fig.40a and Fig.40b A piezoelectric polymer wrapped around a spinal implant component is shown in accordance with an embodiment of the present invention.

[0053] Fig.41a , Fig.41b and Fig.41c An intermediate member of a piezoelectric spinal implant having an insulating outer surface and a conductive inner portion is shown in accordance with an embodiment of the present invention.

[0054] Fig.42An intermediate member made of an insulating material with a conductive coating according to an embodiment of the present invention is shown.

[0055] Fig.43 A configuration of a piezoelectric spinal implant that generates an electric field according to an embodiment of the present invention is shown.

[0056] Fig.44a and Fig.44b An intermediate member having a conductive pin and / or a conductive coating lumen according to an embodiment of the present invention is shown.

[0057] Fig.45a and Fig.45b A selectively conductive piezoelectric element according to an embodiment of the present invention is shown.

[0058] Fig.46a and Fig.46b An embodiment of a piezoelectric spinal implant with conductive jumpers according to an embodiment of the present invention is shown.

[0059] Fig.47a and Figure 47b Different shapes of piezoelectric spinal implants according to embodiments of the present invention are shown.

[0060] Fig.48 A piezoelectric anterior lumbar interbody fusion (ALIF) implant is shown in accordance with an embodiment of the present invention.

[0061] Fig.49 A piezoelectric posterior lumbar interbody fusion (PLIF) implant according to an embodiment of the present invention is shown.

[0062] Fig.50 A piezoelectric lateral lumbar interbody fusion (LLIF) implant according to an embodiment of the present invention is shown.

[0063] Fig.51a , Fig.51b and Fig.51c Test configurations and test data for embodiments of a piezoelectric spinal implant are shown. DETAILED DESCRIPTION

[0064] A spinal implant capable of generating an electric current is provided. Figure 1 As shown, the spinal implant 10 may include a piezoelectric material that generates an electrical charge when pressure is applied thereto to promote tissue stimulation and promote fusion of the implant 10 with the surrounding vertebrae 12. Fig.50 As shown, the design of the implant may include various embodiments, each embodiment generally including upper and lower end plates 14 , 16 , a cage (ie, intermediate body) 18 , and a piezoelectric material element 20 .

[0065] Before explaining in detail at least one aspect of the disclosed and / or claimed (one or more) inventive concepts, it should be understood that the disclosed and / or claimed (one or more) inventive concepts are not limited in their application to the construction details and the arrangement of elements or steps or methods set forth in the following description or shown in the accompanying drawings. The disclosed and / or claimed (one or more) inventive concepts can have other aspects or can be practiced or executed in various ways. Various embodiments comprising different features and aspects are shown in the present disclosure. It should be understood that other embodiments comprising some of these features and aspects and other features and aspects known in the art are also within the scope of the present disclosure, even if such precise combination is not specifically shown or described. In addition, it should be understood that the wording and terminology used herein are for descriptive purposes only and should not be considered as limiting.

[0066] Unless otherwise stated, the following terms used in accordance with the present disclosure shall be understood to have the following meanings.

[0067] Unless otherwise defined herein, technical terms related to the disclosed and / or claimed inventive concepts (one or more) shall have the meanings commonly understood by those of ordinary skill in the art. In addition, unless the context otherwise requires, singular terms shall include plural terms, and plural terms shall include the singular.

[0068] The singular forms "a", "an", and "the" include the plural forms unless the context clearly dictates otherwise or the context of the reference clearly implies a contrary meaning. The terms "comprising" and "consisting of" include more restrictive claims, such as "consisting essentially of" and "consisting of.

[0069] For purposes of the following detailed description, except in any operating examples or where otherwise indicated, numbers expressing, for example, quantities of ingredients used in the specification and claims are to be understood in all instances as modified by the term "about". The numerical parameters set forth in the specification and appended claims are approximations that may vary depending upon the desired properties to be obtained by practicing the present invention.

[0070] All percentages, parts, ratios and proportions used herein are by weight of the total composition, unless otherwise specified. All such weights as they pertain to listed ingredients are based on the active level and, therefore, do not include solvents or by-products that may be included in commercially available materials, unless otherwise specified.

[0071] All publications, articles, treatises, patents, patent publications, and other references cited herein are hereby incorporated in their entirety for all purposes consistent with the disclosure herein.

[0072] The use of the term "at least one" should be understood to include any number of one and more than one, including but not limited to 1, 2, 3, 4, 5, 10, 15, 20, 30, 40, 50, 100, etc. The term "at least one" can be extended to 100 or 1000 or more, depending on the term it is attached to. In addition, the number of 100 / 1000 should not be regarded as limiting, as lower or higher limits may also produce satisfactory results.

[0073] As used herein, the words "comprising" (and any form of including, such as "comprise" and "comprises"), "having" (and any form of having, such as "have" and "has"), "including" (and any form of including, such as "includes" and "include"), or "containing" (and any form of containing, such as "contains" and "contain") are inclusive or open-ended, and do not exclude additional, unrecited elements or method steps.

[0074] The term "each independently selected from the group consisting of..." means that when a group occurs more than once in a structure, each occurrence of the group can be independently selected.

[0075] As shown in Figure 2 to Fig.50 As shown, the spinal implant 12 can include many different embodiments. For ease of description, reference will be made in detail to Figures 2a to 2i However, it should be understood that Figures 3 to Fig.50 The embodiments disclosed in the disclosure may include the same or similar elements, and may include various additional elements.

[0076] Reference now Figure 2a , the piezoelectric spinal implant 12 may include an upper end plate 14, a lower end plate 16, a cage 18 and at least one layer of piezoelectric material 20. In this embodiment, the implant 12 includes a first layer of piezoelectric material 20a and a second layer of piezoelectric material 20b disposed above and below the cage 18, which may be referred to herein as an intermediate body or intermediate layer. The top end plate 14 and the bottom end plate 16 can be used to engage and / or anchor the implant to opposing bone surfaces, such as vertebrae. The piezoelectric elements 20a and 20b can generate an electrical output when subjected to a load or strain, and the cage can be made of a conductive or insulating material. In this embodiment, the elements of the implant 12 can be connected together using a set of tantalum or titanium screws 22 and 24, which are excellent conductors and are configured to pass vertically through the layers of the implant 12, such as Figure 2b shown.

[0077] It should be understood that any suitable material, structure or method may be used to connect the elements, such as tantalum rods (see the embodiments of FIGS. 3 , 4 and 5 ), 3D printing (see the embodiments of FIGS. 10 , 11 and 12 ), or a plurality of other materials, structures or methods. Fig.12 ), saturation or dispersion (FIG. 7), coating (FIG. 8), rivets (embodiment of FIG. 9), adhesives (FIG. 14, FIG. 17, Fig.18 , Fig.21 ), friction fit (Figures 13, 15, 19, 20), swing lock (Figure 16) or a combination thereof (Figure 6).

[0078] Reference now Figure 2c and Figure 2d The upper end plate 14 and the lower end plate 16 are typically made of titanium or other suitable materials, such as polyetheretherketone (PEEK), carbon ceramic composites, tantalum, silicon nitride or other biocompatible materials. It should be understood that the materials used for the upper and lower end plates can have different conductive properties. However, those of ordinary skill in the art will understand that the materials of the end plates and cages should have sufficient conductive and insulating properties to facilitate the transfer of the charge generated by the piezoelectric material to the bone surrounding the implant itself.

[0079] The end plate may include a plurality of teeth 26 having a height ranging from 0.5 mm to 2 mm and protruding vertically from the outer surface of the end plate. The teeth 26 are generally configured to engage with the vertebrae 10 of the spine, thereby fixing or fastening the implant 12 to the vertebrae from the top and bottom of the implant 12. In another embodiment, the implant 12 may be configured to include piezoelectric wings 28 that are configured to extend through the cage 18 and be fixed within the vertebrae, as shown in FIG. 22.

[0080] like Figure 2c As shown, the end plates 14 and 16 can be configured to reduce the height at an angle of about 0° to 25° in the vertical direction (measured from the first tooth to the last tooth of the implant) so that the front portion (A) of the implant is thicker than the back portion (B). Typically, the implant is about 7mm to about 15mm from top to bottom (measured from tooth to tooth), about 8mm to about 2mm in width, and about 22mm to about 40mm in length. Typically, the slope of the end plates is configured to match the slope and curvature of the patient's spine so that it can fit snugly between the vertebrae.

[0081] The cage 18 can be made of a suitable polymer material, such as PEEK, 3D printed titanium carbon fiber, or other suitable biocompatible materials that can isolate the current generated by the piezoelectric material and provide visibility for postoperative assessment.

[0082] Reference now Figure 2g to Figure 2i , the main components of the spinal implant 12 can have an undulating or wavy shape. Figure 2gAs shown, the upper end plate 14 includes a plurality of teeth 26 along its upper outer surface and an undulating lower inner surface. This surface is configured to conform to the upper surface of the cage 18, which is typically about 1 mm at its thinnest portion and about 10 mm at its thickest portion. Similarly, the lower end plate 16 has a lower outer surface with a plurality of teeth 26 and an undulating upper inner surface that is configured to conform to the shape of the lower surface of the cage 18. In this embodiment, two layers of piezoelectric material 20a and 20b, such as but not limited to PVDF (or polyvinylidene fluoride) film, are disposed between each end plate 14, 16 and the cage 18. The layers 20a and 20b are typically molded to the shape of the surface between which they are disposed and have a thickness of 25 μm to 1 mm.

[0083] like Figure 2f and Figure 2i As shown, the upper end plate 14 and the lower end plate 16 are configured to include two threaded holes 30a, 30b and 32a, 32b, through which the screws 22 and 24 are placed. When the screws 22 and 24 pass through the holes, the head of each screw is generally configured to be located below the upper surface of the end plate teeth, such as Figure 2e The areas between holes 30a, 30b and 32a, 32b can be empty, as shown. Figure 2i In addition, the piezoelectric layers 20a, 20b and the cage 18 may also be configured to be hollow at the center thereof.

[0084] Figures 3a to 3f 300. The embodiment of the piezoelectric spinal implant 300 is shown in top perspective, top view, side view, partially transparent top perspective, bottom view, and partially transparent side view. The embodiment has one or more layers of piezoelectric material 302, assembled between an end plate 304 (which may be titanium) facing the bone and an insulating layer 306 (which may be PEEK, for preventing short circuits or offsetting positive / negative electrical output). Conductive leads (e.g., tantalum or titanium pins 308) may be used to contact the piezoelectric material and transmit the electrical output to the outside of the implant.

[0085] Figure 4a to Figure 4b 4 is a top perspective view and a partially transparent top perspective view of an embodiment of a piezoelectric spinal implant 400. This embodiment has multiple layers of piezoelectric material 402 assembled in series. The piezoelectric elements can be assembled between end plates 404 facing the bone, with or without an insulating layer 406 between the piezoelectric elements. Conductive leads (e.g., tantalum pins 408) are placed throughout the implant to transfer charge from the piezoelectric elements to the outside of the implant.

[0086] Figure 5a to Figure 5c5 is a side, partially transparent front and side perspective view of an embodiment of a piezoelectric spinal implant 500. The embodiment has one or more layers of piezoelectric material 502 connected to a conductive block 504, which is used to dissipate the electrical output at a focal point inside, outside, or on both sides of the implant. The conductive block can be directly in contact with the piezoelectric material 502, or it can be kept at a certain distance from the piezoelectric material 502 and connected by a conductive lead (e.g., a tantalum pin 506). The conductive block 504 can dissipate the electrical output through a window in the implant, which exposes one or more surfaces of the conductive block to the outside of the implant.

[0087] Figure 6a to Figure 6b 6 are top and side perspective views of an embodiment of a piezoelectric spinal implant 600. This embodiment shows an implant having a piezoelectric element 602 surrounded by a mechanical lattice or other load-bearing structure that transfers mechanical forces directly or indirectly to the piezoelectric element from the top 606 and bottom 608 implant surfaces.

[0088] Figure 7a to Figure 7b is a side perspective view of an embodiment of a piezoelectric spinal implant 700. This embodiment shows a titanium 702 or PEEK 704 implant coated or saturated with a piezoelectric material 706.

[0089] Figure 8a to Figure 8b is a side perspective view of an embodiment of a piezoelectric spinal implant 800. This embodiment shows a titanium 802 or PEEK 804 implant with the top and bottom surfaces coated with piezoelectric material 806.

[0090] Figure 9a to Figure 9b 900. This embodiment shows one or more piezoelectric elements 902 assembled between top 904 and bottom 906 end plates and a central insulating or conductive material 908. The assembly can be constructed using fasteners 910 (e.g., rivets, screws, or pins) to prevent disassembly but allow mechanical loads to be transferred from the end plates to the piezoelectric material.

[0091] Figures 10a to 10c 1 is a side perspective and detail view of an embodiment of a piezoelectric spinal implant 1000. This embodiment shows a piezoelectric element 1002 that is above or flush with the mechanical support implant to which forces applied to the mechanical support implant will be transferred.

[0092] Figure 11a to Figure 11b is a side perspective view of an embodiment of a piezoelectric spinal implant 1100. This embodiment shows a piezoelectric element 1102 that is oval, annular, rectangular, or pill-shaped, and can be above or flush with a mechanical support implant to which forces applied will be transferred.

[0093] Fig.12 is a top perspective view of an embodiment of a piezoelectric spinal implant 1200. This embodiment shows a piezoelectric element 1202 that is shorter than or flush with the mechanical support implant, and forces to the mechanical support implant will drive the piezoelectric element 1202. The implant 1200 can have a protrusion or spike 1204 that extends above or flush with the piezoelectric element 1202.

[0094] Figures 13a to 13c 1 is a side perspective view and a side view of an embodiment of a piezoelectric spinal implant 1300. This embodiment shows a piezoelectric insert 1302 added independently to a conventional mechanical support implant. The insert can be located above the conventional implant, flush with the conventional implant, or below the conventional implant. The insert can be inserted into the inner cavity of the spinal implant.

[0095] Figure 14a to Figure 14b 1 is a side perspective and exploded view of an embodiment of a piezoelectric spinal implant 1400. This embodiment depicts a wave design that non-uniformly loads the piezoelectric element 1402. The wave can be from front to back, side to side, or both, and can be used across the entire width and length of the implant or over a portion of the area.

[0096] Figures 15a to 15c 1 is a side perspective view and top detailed view of an embodiment of a piezoelectric spinal implant 1500. This embodiment shows a mechanically loaded lattice 1502 or other load bearing geometry that allows force to be transferred from end plates 1504 to one or more piezoelectric elements 1506 located between the end plates. The lattice can have a uniform stiffness throughout the implant, or a variable stiffness that varies based on location.

[0097] Figures 16a to 16d 1600 is a front and side perspective view of an embodiment of a piezoelectric spinal implant 1600. This embodiment shows a mechanically loaded lattice or other load-bearing geometry that allows force to be transmitted from the end plates to the piezoelectric element 1602 located between the end plates. The lattice can have a uniform stiffness throughout the implant, or a variable stiffness that varies based on position. The piezoelectric element 1602 can be inserted into a slot built into the implant and secured in place using a protrusion or other blocking mechanism (e.g., a swing lock 1604 or a sliding protrusion 1606). The assembly can include an insulating sheet, membrane, or block 1608 on one side of the piezoelectric element 1602 to prevent short circuits or offset positive / negative outputs.

[0098] Figure 17a to Figure 17b1 is a right side and side perspective view of an embodiment of a piezoelectric spinal implant 1700. This embodiment shows a mechanically loaded lattice 1702 or other load bearing geometry that allows an applied force to be transferred from end plates 1704 to piezoelectric elements 1706 located between the end plates 1704. The lattice 1702 can have a uniform stiffness throughout the implant, or a variable stiffness that varies based on location. The lattice 1702 or structural geometry can be in the shape of a flat rectangular block, or can have a wave shape or other geometric fluctuations to provide an uneven distribution or force to the piezoelectric material.

[0099] Fig.18 1 is a right side perspective view of an embodiment of a piezoelectric spinal implant 1800. This embodiment shows a mechanically loaded lattice 1802a and 1802b or other load bearing geometry that allows an applied force to be transferred from the end plates 1804 to the piezoelectric element 1806 located between the end plates 1804. The lattices 1802a and 1802b can have a uniform stiffness throughout the implant, or have a variable stiffness that varies based on location. For example, the lattice can have a soft portion 1802a and a hard portion 1802b. The lattice or structural geometry can be in the shape of a flat rectangular block, or can have a wavy shape or have other geometric fluctuations to provide an uneven distribution or force to the piezoelectric material.

[0100] Figures 19a to 19f are right side, top and side perspective views of an embodiment of a piezoelectric spinal implant 1900. This embodiment shows an implant having a piezoelectric element 1902 on the side opposite a flexible post or hinge 1904 that allows applied forces to be transferred from an end plate 1906 to the piezoelectric element.

[0101] Figures 20a to 20c are partially transparent rear, top and rear perspective views of an embodiment of a piezoelectric spinal implant 2000. This embodiment shows one or more rods or rails 2002 mounted in an implant constructed of a conductive or insulating solid material 2004 and / or a load bearing lattice 2006.

[0102] Fig.21 is a front perspective view of an embodiment of a piezoelectric spinal implant 2100. This embodiment shows an implant constructed of one or two piezoelectric end plates 2102 assembled to a central core 2104 which can be made of a conductive or insulating material. The central core can be a solid block, a uniform or non-uniform lattice, or a combination of solid and lattice structures.

[0103] Figures 22a to 22d1 are front, side, and top perspective views of an embodiment of a piezoelectric spinal implant. This embodiment shows a bone anchor made of a piezoelectric material that passes through the implant and extends into the bone. In this embodiment, the implant 10 can be configured to include piezoelectric wings 28 that are configured to extend through the cage 18 and be fixed within the vertebra.

[0104] Fig.23 is a schematic diagram of a test setup that uses a force vibrator to replicate the forces a user applies to an implant while walking.

[0105] In one embodiment, using Fig.23 The experimental setup shown calculates the current produced by the piezoelectric film layer, which is designed to simulate the frequencies associated with the user's natural walking gait. Testing was conducted by attaching the spinal implant to a vibrator 34, which is capable of generating approximately 100 pounds of force. A function generator 36 controls the vibrator 34, and the frequency of the applied force is expressed in voltage. A 2Hz signal is then sent to the vibrator 34, which represents a typical bipedal walking speed. The implant is then advanced into a force sensor 38, which records the force in mV on an oscilloscope 40. Positive and negative leads are attached to the implant as well as a power amplifier 42 and an ammeter 44, which record the current and voltage output experienced by the implant surface. From the data described below and Figure 24 to Figure 29 The data shown shows that as pressure / force is applied to the piezoelectric material on the implant, an electric current is generated. As the force applied to the implant increases, the current generated by the implant itself also increases.

[0106] Specifically, the current generated by the piezoelectric film at a vibration power of 10 V was determined to be about -175 nA to about 75 nA, and the voltage was about 5 mV to about -2.5 mV. Fig.24 and Fig.25 At a vibration power of 15 V, the generated current and voltage are approximately -220 nA to approximately 165 nA and 9 mV to approximately -6.5 mV, respectively. Fig.26 and Fig. 27 At about 20V, the current is about -250nA to about 150nA, and the voltage is about 13mV to about -8mV, as shown. Fig.28 and Fig.29 As shown. Fig.30 As shown, the greater the force applied to the implant, the greater the current, and the relationship is linear. Based on the linear relationship demonstrated in the experimental setup, it can be expected that the force experienced during normal walking (about 1000 Newtons) will increase the expected current to about 0.5uA.

[0107] Figure 24 to Figure 29is a graphical representation of the current and voltage produced by the implant at vibration powers of 10, 15, and 20 V at a frequency of 2 Hz.

[0108] Fig.30 is a graphical representation of the current generated by the implant under different forces.

[0109] Reference now Fig.31 , shows an exploded view of an embodiment of a piezoelectric spinal implant 3100 (which may be referred to as a spinal intervertebral body). The spinal implant 3100 includes a top end plate 3102, which may have a machined hole through its side, and a plurality of teeth or other protrusions extending from its upper surface (i.e., outer surface). The top end plate 3102 may have a bottom or inner surface having an undulating, wavy, serrated, or another non-planar structural geometry that distributes the compressive or shearing force applied to the end plate unevenly to the piezoelectric material 3106. The bottom end plate 3112 may similarly have a non-planar inner surface and a plurality of teeth or protrusions on its outer or bottom surface that distribute the force unevenly to the piezoelectric material. The bottom end plate 3112 may also have a machined hole through its side. The spinal implant 3100 may also include an assembly pin 3104, which is configured to be inserted into the machined holes on the top end plate 3102 and the bottom end plate 3112, and further inserted into the connecting bracket 3110. The piezoelectric element 3106 can be configured to provide an electrical output corresponding to a load applied to the outer surface of the top and bottom end plates. The top and bottom end plates can also be referred to as first and second end plates, and can be made of insulating materials or conductive materials. They can be attached to the first and second vertebrae, respectively. The connecting bracket 3110 can be made of insulating materials or conductive materials.

[0110] The piezoelectric element 3106 can be substantially planar in shape prior to assembly and deform into a non-planar shape, such as having undulations, waves, zigzags, curves, creases, and / or bends, due to the application of forces to the top and bottom end plates. The piezoelectric element 3106 can conform to the inner surfaces of the end plates and the upper and lower surfaces of the cage 3108. The force can be a force applied due to assembly, a compressive force (e.g., spinal compression force), or a shear force, or a combination of these forces. The force can be approximately 10N, 25N, 50N, 100N, 200N, 500N, 700N, 1000N, 1500N, 3000N, 5000N, or 10000N. The force can be variable and range between an upper limit and a lower limit. The electrical output may include a voltage of about 0.1 mV, 0.3 mV, 0.5 mV, 1 mV, 10 mV, 25 mV, 100 mV, 200 mV, 500 mV, 700 mV, 1 V, 2 V, 3 V, 4 V, 5 V, 6 V, 7 V, 10 V, 15 V, or 20 V. The voltage output may be variable and range between upper and lower limits. The electrical output can include about 50nA, 100nA, 500nA, 1000nA, 3000nA, 5000nA, 7000nA, 10000nA, 50000nA, 100000nA, 250000nA, 500000nA, 750000nA, 1mA, 5mA, 10mA, 15mA, 25mA, 35mA or 50mA. The current output can be variable and range between the upper and lower limits. All ranges between the above arbitrary values ​​are disclosed herein.

[0111] Spinal implant 3100 also includes cage 3108 (also called intermediate, or intermediate layer). Cage 3108 can be made of insulating material or conductive material. Its top and bottom surfaces can have undulating, wavy, zigzag, curved, bent, creased or other non-planar structural geometries. When force is applied to the top and bottom end plates, this non-planar structural geometry may cause or further help (one or more) piezoelectric elements 3106 to have a non-planar shape.

[0112] Reference now Fig.32a and Figure 32b , an embodiment of a piezoelectric spinal implant 3200 is shown. Fig.32a The assembled implant is shown. Figure 32b An exploded view of the implant is shown. This embodiment includes a top end plate 3202, a bottom end plate 3204, a single piezoelectric element 3206, a connecting bracket 3208, and an assembly pin 3210. These components can be connected to Fig.31 Similar to the components described in .

[0113] Reference now Fig.33a , Figure 33b and Fig.33c, several embodiments of piezoelectric spinal implants are shown. The spinal implant includes a top end plate 3302, a bottom end plate 3304, and piezoelectric elements 3306a and 3306b. As shown, the piezoelectric elements can be placed in any positive or negative orientation. Other embodiments may also have piezoelectric elements in various positive and negative orientations.

[0114] Reference now Fig.34a and Fig.34b , several embodiments of piezoelectric spinal implants are shown. These embodiments include a piezoelectric element composed of at least one layer. These layers can be piezoelectric layers 3402 or non-piezoelectric layers 3404. Non-piezoelectric layer 3404 will act as an insulator. For each piezoelectric element, there are one or more piezoelectric layers, such as Fig.34b As shown, there can be zero, one or more non-piezoelectric layers, such as Fig.34a The piezoelectric layer may be a piezoelectric polymer, and the non-piezoelectric layer may be a non-piezoelectric polymer.

[0115] Reference now Fig.35 , shows an embodiment of a piezoelectric spinal implant 3500. The implant 3500 includes: an assembly pin 3502 made of machined titanium or other suitable material; a top end plate 3504 made of 3D printed titanium, which has a contoured bottom surface; a piezoelectric element 3506, which is deformed to the contour during assembly and strained under compression or shear loads to produce an electrical output; an intermediate insulator 3508 made of PEEK (polyetheretherketone) or other suitable insulator, which has contoured top and bottom surfaces to match the inner surface of the end plate; a second piezoelectric element 3510, which is deformed to the contour during assembly and strained under compression or shear loads to produce an electrical output; and a bottom end plate 3512 made of 3D printed titanium, which has a contoured top surface and has a connecting element configured to receive the assembly pin 3502 to hold the assembled implant together.

[0116] Reference now Fig.36a and Fig.36b , shows an embodiment of a piezoelectric spinal implant 3600 under load. Fig.36a In FIG. 3 , implant 3600 is under a compressive load. Compression force 3602 acts on the top and bottom surfaces of implant 3600. In FIG. Fig.36b 3600. The implant is under shear load. Shear forces or forces with shear components 3604 act on the top and bottom surfaces of the implant 3600. Both the compressive (or axial) load and the shear load of the implant can activate the piezoelectric element(s). These forces can be the spinal forces to which the implant is subjected when implanted between vertebrae.

[0117] Reference now Fig.37a , Fig.37b and Fig.37c, several embodiments of piezoelectric spinal implants are shown. Fig.37a , the spinal implant is configured with piezoelectric elements 3706a and 3706b in matching orientations, with the negative side facing the top of the implant 3702. Fig.37a In the embodiment, the intermediate body 3704 acts as an insulator, and the end plates act as conductors. Fig.37a The configuration results in a larger electric field from the top end plate to the bottom end plate. It is also contemplated that the configuration of piezoelectric elements 3706a and 3706b can be reversed, which would result in an electric field with a reversed direction. Figure 37b and Fig.37c , the spinal implant is configured so that the piezoelectric elements are in opposite or mirrored orientations and the intermediate body 3708 is a conductor. This creates multiple smaller electric fields as shown.

[0118] Reference now Fig.38 , shows an embodiment of a piezoelectric spinal implant 3800. In this embodiment, the implant 3800 includes a top end plate 3802, a bottom end plate 3806, a middle body 3804, and a piezoelectric element 3808 folded and / or wrapped around the middle body 3804.

[0119] Reference now Fig.39a and Fig.39b , shows an embodiment of a piezoelectric spinal implant 3900b in which the piezoelectric element 3900a is selectively metallized or piezoelectrically neutralized (aka selectively conductive). The surface properties can be altered by metal surface application or other conductive materials to make selected areas conductive, or by using laser treatment or other surface energy modification methods to eliminate the piezoelectric properties in the treated area.

[0120] exist Fig.39a In FIG. 3 , the dark stripes 3902 represent the piezoelectric portion of element 3900a, while the light stripes 3904 represent the non-piezoelectric portion. Fig.39b , spinal implant 3900b includes a top end plate 3906, a selectively metallized piezoelectric element 3900a, an intermediate body 3912, a second piezoelectric element 3914 (which may also be selectively metallized), a bottom end plate 3916, and a connecting bracket 3908. The selective metallization of the piezoelectric element 3900a provides an electric field 3910 in multiple regions along the edge, thereby providing a more uniform distribution of electrical output.

[0121] Reference now Fig.40a and Fig.40b In accordance with various embodiments of the present invention, it may be seen that a piezoelectric polymer (or other material) is wrapped around a structural implant element (e.g., an end plate or intermediate body). Fig.40a In the embodiment of the present invention, the piezoelectric polymer 4004 is wrapped around the side walls of the implant components. Fig.40bIn FIG. 4 , piezoelectric polymer 4008 is wrapped around the top, bottom, and side walls of the implant element.

[0122] Reference now Fig.41a , Fig.41b and Fig.41c , showing an intermediate 4100 according to various embodiments of the present invention. Fig.41a An intermediate body 4100 is shown having a conductive inner portion 4104 and an insulating outer portion (or housing) 4102. The insulating outer portion 4102 can be used to modify the electric field generated by the piezoelectric element. Fig.41b A piezoelectric spinal implant is shown with the interior portion 4104 of the intermediate body exposed. Fig.41c A piezoelectric spinal implant is shown with an insulating outer portion 4102 of the intermediate body exposed.

[0123] Reference now Fig.42 , shows an intermediate body 4200 according to an embodiment of the present invention. The intermediate body 4200 includes a PEEK body 4202 having a titanium coated top surface 4204. The bottom surface (not shown) can also be titanium coated. The titanium coated PEEK surface can extract energy from the entire surface of the piezoelectric layer.

[0124] Reference now Fig.43 , shows a piezoelectric spinal implant according to an embodiment of the present invention. The piezoelectric element is configured with the negative electrode facing up and the positive electrode facing down. The intermediate body is an insulator, represented by "C", so that when the piezoelectric element is activated, an electric field as shown in the figure is generated, across the gap between the positively and negatively charged end plates.

[0125] Reference now Fig.44a and 44b , showing an example of an intermediate. Fig.44a In the embodiment, the titanium pin 4404 extends from the top surface of the PEEK having the titanium coating 4402 to the bottom surface, thereby Fig.43 The [Top+] in the image is electrically connected to the [Bottom-]. Fig.44b An intermediate body is shown having a titanium coating 4402 on its top and bottom (not shown) surfaces and also having a coating on the interior of the inner cavity 4406. Figure 44b The embodiments can be used with Fig.44a The embodiments are used in combination or in place of each other to achieve Fig.43 The electric field effect.

[0126] Reference now Fig.45a and Fig.45b , shows embodiments of selectively conductive piezoelectric elements. These embodiments can be selectively metallized or piezoelectrically neutralized by the same process as used with respect to FIG. 39. Fig.45aIn a piezoelectric device, the outside of the element is insulating, or non-piezoelectric 4504, while the inside of the element is piezoelectric 4502. Fig.45b In FIG. 4 , the outer and inner boundaries are non-piezoelectric 4504, while the remainder (shown in dark grey) is piezoelectric. This design provides that the electric field is focused along the conductive element and does not short along the periphery.

[0127] Reference now Fig.46a and Fig.46b , shows an embodiment of a piezoelectric spinal implant including an additional conductive jumper 4606. Fig.46a The implant shown includes a conductive end plate 4602, a piezoelectric element 4604, an insulating intermediate body 4608, an internal component 4610, and a conductive jumper 4606, which also includes exposed leads flush with the outer surface of the intermediate body. Fig.46b The embodiment is further explained in the figure. Jumper 4606 contacts the negative side of piezoelectric element 4604, and conductive end plate 4602 contacts the positive side of piezoelectric element 4604, so that current flows between positive end plate 4602 and conductive jumper 4606 having a high concentration of negative charge, thereby generating an electric field with a large volume. Jumper 4606 can contact internal components (e.g., connecting brackets or connecting elements) 4610, such as Fig.46b or may be offset and contained within insulating intermediate body 4608, as shown on the right side of Fig.46b as shown on the left.

[0128] Reference now Fig.47a and Figure 47b , the embodiment of the piezoelectric spinal implant of different shapes is shown.The implant assembly can have various shapes and sizes.Implant according to the present disclosure can be ALIF (anterior lumbar interbody fusion) implant, PLIF (posterior lumbar interbody fusion) implant or L-LIF (lateral lumbar interbody fusion) implant.Implant according to the present disclosure can also be used for other spinal surgeries, such as cervical and thoracic spine surgery.

[0129] Reference now Fig.48 , an embodiment of a piezoelectric ALIF spinal implant 4802 is shown. The implant 4802 is shown disposed between vertebrae in oblique, anterior-posterior, and lateral views. A top perspective view of the implant 4802 is also shown.

[0130] Reference now Fig.49 , an embodiment of a piezoelectric PLIF spinal implant 4902 is shown. The implant 4902 is shown disposed between vertebrae in oblique, anterior-posterior, and lateral views. A top perspective view of the implant 4902 is also shown.

[0131] Reference now Fig.50, an embodiment of a piezoelectric L-LIF spinal implant is shown. In oblique, anterior-posterior, and lateral views, the implant 5002 is shown disposed between vertebrae. A top perspective view of the implant 5002 is also shown.

[0132] As used herein, "suitable for" or "configured to" is intended to be open and inclusive language and does not exclude devices that are suitable for or configured to perform additional tasks or steps. In addition, the use of "based on" is intended to be open and inclusive, because the process, steps, calculations or other actions based on one or more of the conditions or values ​​may be based on additional conditions or values ​​in practice. The headings, lists and numbers contained herein are only for convenience of explanation and are not intended to be limiting.

[0133] Reference now Fig.51a , Fig.51b and Fig.51c , showing the test configuration and test data of an embodiment of a piezoelectric spinal implant. Fig.51a A test configuration of an embodiment of a piezoelectric spinal implant is shown inside a mechanical testing machine with electrodes 5102 on the top end plate and a ground lead 5104 on the bottom end plate. The end plates may be subject to compressive and / or shear forces. Fig.51b and Fig.51c Shown are test results where the electrical output was measured at the same frequency as the mechanical load - the measured voltage output was linearly related to the load force.

[0134] It should also be understood that, although the terms "first", "second", etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, a first node may be referred to as a second node, and similarly, a second node may be referred to as a first node, as long as all occurrences of the "first node" are consistently renamed and all occurrences of the "second node" are consistently renamed, the meaning of the description will be changed. The first node and the second node are both nodes, but they are not the same node.

[0135] The terms used herein are only used to describe specific embodiments and are not intended to limit the claims. As used in the description of the embodiments and the appended claims, the singular forms "one", "an" and "the" are intended to also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and covers any and all possible combinations of one or more related listed items. It should also be understood that when the terms "include" and / or "comprising" are used in this specification, the presence of the features, integers, steps, operations, elements and / or components is specified, but the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof is not excluded.

[0136] As used herein, the term "if" may be interpreted as "when" or "upon" or "in response to determining" or "upon determining" or "in response to detecting" the stated precondition is true, depending on the context. Similarly, the phrase "if it is determined that [the stated precondition is true]" or "if [the stated precondition is true]" or "when [the stated precondition is true]" may be interpreted as "upon determining" or "in response to determining" or "upon determining" or "upon detecting" or "in response to detecting" the stated precondition is true, depending on the context.

[0137] The above description and the content of the invention of the present invention should be understood to be illustrative and exemplary in all aspects, rather than restrictive, and the scope of the present invention disclosed herein should not be determined only according to the detailed description of the illustrative embodiments, but should be determined according to the full scope allowed by the patent law. It should be understood that the embodiments shown and described herein are only used to illustrate the principles of the present invention, and those skilled in the art can make various modifications without departing from the scope and spirit of the present invention.

Claims

1. A spinal implant capable of generating an electrical output, comprising: a first end plate having an inner surface; a second end plate having an inner surface; as well as A first piezoelectric element is disposed between an inner surface of the first end plate and an inner surface of the second end plate, wherein the piezoelectric element has a non-planar shape when a force is applied to the first end plate and the second end plate.

2. The spinal implant according to claim 1, wherein: An inner surface of the first end plate and an inner surface of the second end plate are non-planar.

3. The spinal implant according to claim 2, wherein: An inner surface of the first end plate and an inner surface of the second end plate are corrugated.

4. The spinal implant according to claim 2, wherein: The first piezoelectric element has an upper surface conforming to the inner surface of the first end plate, and a lower surface conforming to the inner surface of the second end plate.

5. The spinal implant according to claim 1, wherein: The force is at least one of an assembly force and a spinal compression force.

6. The spinal implant according to claim 1, wherein: The force is between 25N and 10000N.

7. The spinal implant of claim 1, further comprising: A second piezoelectric element is disposed between the first end plate and the second end plate; as well as An intermediate body is disposed between the first piezoelectric element and the second piezoelectric element and has a non-planar top surface and a non-planar bottom surface.

8. The spinal implant according to claim 7, in, The first piezoelectric element has an upper surface conforming to the inner surface of the first end plate, and a lower surface conforming to the top surface of the intermediate body; and The second piezoelectric element has an upper surface that matches the bottom surface of the intermediate body, and a lower surface that matches the inner surface of the second end plate.

9. The spinal implant according to claim 7, wherein: The intermediate body serves as an insulator.

10. The spinal implant according to claim 9, wherein: The first and second end plates are electrically conductive, and the spinal implant further comprises a plurality of electrically conductive jumpers disposed through the intermediate body, wherein one end of each jumper is connected to a surface of the piezoelectric element and the other end of each jumper is flush with an outer surface of the intermediate body.

11. The spinal implant of claim 7, further comprising: At least one connecting element is fixed to both the first end plate and the second end plate, the connecting element serving as an insulator, wherein the intermediate body serves as a conductor.

12. The spinal implant of claim 1, wherein: The first end plate and the second end plate have a non-uniform outer surface texture.

13. The spinal implant of claim 1, wherein: The piezoelectric element comprises a plurality of different layers, wherein at least one of the different layers is piezoelectric.

14. The spinal implant according to claim 13, wherein: The piezoelectric element further includes at least one non-piezoelectric layer.

15. The spinal implant of claim 1, wherein: The first and second end plates have outer surfaces, and wherein the piezoelectric element is configured to generate an electrical output corresponding to a load applied to the outer surfaces of the first and second end plates.

16. A method of using the spinal implant of claim 1, the method comprising: attaching the first endplate to a first vertebra; as well as The second endplate is attached to the second vertebra.

17. A spinal implant capable of generating an electrical output, comprising: a first end plate having a non-planar inner surface; a second end plate having a non-planar inner surface; as well as The first piezoelectric element is disposed between the inner surface of the first end plate and the inner surface of the second end plate.

18. The spinal implant of claim 17, wherein: The first piezoelectric element has an upper surface conforming to the inner surface of the first end plate, and a lower surface conforming to the inner surface of the second end plate.

19. The spinal implant of claim 17, further comprising: A second piezoelectric element is disposed between the first end plate and the second end plate; as well as An intermediate body is disposed between the first piezoelectric element and the second piezoelectric element and has a non-planar top surface and a non-planar bottom surface.

20. The spinal implant according to claim 19, in, The first piezoelectric element has an upper surface conforming to the inner surface of the first end plate, and a lower surface conforming to the top surface of the intermediate body; and The second piezoelectric element has an upper surface that matches the bottom surface of the intermediate body, and a lower surface that matches the inner surface of the second end plate.

21. The spinal implant of claim 19, wherein: The intermediate body serves as an insulator.

22. The spinal implant of claim 21, wherein: The first and second end plates are electrically conductive, and the spinal implant further comprises a plurality of electrically conductive jumpers disposed through the intermediate body, wherein one end of each jumper is connected to a surface of the piezoelectric element and the other end of each jumper is flush with an outer surface of the intermediate body.

23. The spinal implant of claim 19, further comprising: At least one connecting element is fixed to both the first end plate and the second end plate, the connecting element serving as an insulator, wherein the intermediate body serves as a conductor.

24. The spinal implant of claim 17, wherein: The first end plate and the second end plate have a non-uniform outer surface texture.

25. The spinal implant of claim 17, wherein: The piezoelectric element comprises a plurality of different layers, wherein at least one of the different layers is piezoelectric.

26. The spinal implant of claim 25, wherein: The piezoelectric element further includes at least one non-piezoelectric layer.

27. The spinal implant of claim 17, wherein: The first and second end plates have outer surfaces, and wherein the piezoelectric element is configured to generate an electrical output corresponding to a load applied to the outer surfaces of the first and second end plates.

28. A method of using the spinal implant of claim 17, the method comprising: attaching the first endplate to a first vertebra; as well as The second endplate is attached to the second vertebra.

29. A spinal implant capable of generating an electric current, comprising: a first end plate having an inner surface; a second end plate having an inner surface; a first piezoelectric element disposed between an inner surface of the first end plate and an inner surface of the second end plate; as well as An intermediate body having a structural geometry that unevenly distributes the compressive force applied to the end plates to the piezoelectric material.

30. The spinal implant of claim 29, further comprising: The second piezoelectric element is arranged between the intermediate body and the second end plate.

31. The spinal implant according to claim 30, in, The first piezoelectric element has an upper surface conforming to the inner surface of the first end plate, and a lower surface conforming to the top surface of the intermediate body; and The second piezoelectric element has an upper surface that matches the bottom surface of the intermediate body, and a lower surface that matches the inner surface of the second end plate.

32. The spinal implant of claim 30, wherein: The intermediate body serves as an insulator.

33. The spinal implant of claim 32, wherein: The first and second end plates are electrically conductive, and the spinal implant further comprises a plurality of electrically conductive jumpers disposed through the intermediate body, wherein one end of each jumper is connected to a surface of the piezoelectric element and the other end of each jumper is flush with an outer surface of the intermediate body.

34. The spinal implant of claim 30, further comprising: At least one connecting element is fixed to both the first end plate and the second end plate, the connecting element serving as an insulator, wherein the intermediate body serves as a conductor.

35. The spinal implant of claim 29, wherein: The first end plate and the second end plate have a non-uniform outer surface texture.

36. The spinal implant of claim 29, wherein: The piezoelectric element comprises a plurality of different layers, wherein at least one of the different layers is piezoelectric.

37. The spinal implant of claim 36, wherein: The piezoelectric element further includes at least one non-piezoelectric layer.

38. The spinal implant of claim 29, wherein: The first and second end plates have outer surfaces, and wherein the piezoelectric element is configured to generate an electrical output corresponding to a load applied to the outer surfaces of the first and second end plates.

39. A method of using the spinal implant of claim 29, the method comprising: attaching the first endplate to a first vertebra; as well as The second endplate is attached to the second vertebra.

40. The spinal implant of claim 29, wherein: The structural geometry is a change in material stiffness and / or material shape.

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