Polymeric intervertebral devices with metal end caps and end plate grooves and methods of making same

Abstract

Intervertebral implants formed by disposing a polymeric body between an upper metal endplate and a lower metal endplate and methods of forming these implants are disclosed. In some embodiments, the intervertebral implant includes a plurality of porous metal sheets and a plurality of non-porous metal sheets, the porous metal sheets and the non-porous metal sheets being bonded to form a metal endplate. In various embodiments, the polymer body may be filled between the upper metal end plate and the lower metal end plate by an injection molding process. In various embodiments, the metal end plate may include a plurality of grooves created by a subtractive manufacturing process. In various embodiments, the metal endplate may also include providing a surface treatment to produce nanoscale metal oxide nanostructures.

Description

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 591,285, filed October 18, 2023, the entire contents of which are incorporated herein by reference.

[0002] Cross-references to related applications

[0003] This application incorporates by reference the following patent applications: U.S. Patent No. 11,717,422, filed May 14, 2021, entitled "Spinal Implant System and Method"; U.S. Patent No. 11,096,796, filed March 4, 2013, entitled "Interbody spinal implant having a roughened surfacetopography on one or more internal surfaces"; and U.S. Patent No. 10,821,000, filed June 29, 2017, entitled "Titanium implant surfaces free from alpha case and with enhanced osteoinduction". The entire disclosure of each of these documents is incorporated herein by reference in its entirety. Technical Field

[0004] This technology relates in general to methods for manufacturing surgical implants and methods for using surgical implants and devices for insertion into the human body. Background Technology

[0005] Spinal conditions and ailments such as degenerative disc disease, herniated disc, osteoporosis, spondylolisthesis, stenosis, scoliosis and other curvature abnormalities, kyphosis, tumors, and fractures can be caused by factors including trauma, disease, and degenerative conditions resulting from injury and aging. Spinal conditions typically lead to symptoms including deformities, pain, nerve damage, and partial or complete loss of mobility.

[0006] Non-surgical treatments (such as medication, rehabilitation, and exercise) may be effective but may not relieve the symptoms associated with these conditions. Surgical treatments for these spinal conditions include, for example, fusion, fixation, correction, partial or complete discectomy, vertebrectomy, laminectomy, and implantable prostheses. As part of these surgical treatments, spinal structures (such as bone fasteners, spinal rods, and intervertebral devices) can be used to provide stability to the treated area. For example, during surgical treatment, an intervertebral implant can be delivered to the surgical site to fix it to the bone to immobilize the joint. This disclosure describes improvements over these techniques. Summary of the Invention

[0007] The technology disclosed herein relates in general to the manufacture of intervertebral implants, for example, having metal endplates and polymer bodies. In one aspect, the method may include: (a) bonding a first plurality of porous metal sheets to a first side of a non-porous metal sheet and bonding a second plurality of porous metal sheets to a second side of the non-porous metal sheet opposite to the first side by applying a bonding process, the non-porous metal sheet creating a solid barrier between the first plurality of porous metal sheets and the second plurality of porous metal sheets, thereby forming an upper metal end plate and a lower metal end plate, respectively; (b) forming a polymer body by injection molding a thermoplastic polymer between a lower surface of the upper metal end plate and an upper surface of the lower metal end plate, the injection molding of the thermoplastic polymer impregnating corresponding pore spaces on the first plurality of porous metal sheets of the upper metal end plate and corresponding pore spaces on the first plurality of porous metal sheets of the lower metal end plate, thereby producing an implant blank; and (c) forming grooves on the implant blank by applying a machining process to the exposed surfaces of the upper metal end plate and the lower metal end plates.

[0008] In various embodiments, following the machining process in step (c), the method may further include (d) an anodizing step of the exposed surfaces of the upper and lower metal end plates. In some embodiments, the machining in step (c) may further include a subtractive machining step, which includes at least one of the following: electrical discharge machining, milling, lathe machining, deburring sawing, or sanding. In some embodiments, during the injection molding process in step (b), each non-porous metal sheet can prevent the thermoplastic polymer from flowing from the first plurality of porous metal sheets into the second plurality of porous metal sheets.

[0009] In some embodiments, the bonding of the porous and non-porous metal sheets can be between about 0.20 mm and about 0.30 mm thick. In various embodiments, the bonding process in step (a) may include stacking a plurality of porous metal sheets such that a majority of the corresponding pores of adjacent stacked porous metal sheets are offset from each other, wherein the plurality of porous metal sheets may include about 45% to about 70% by volume voids. In some embodiments, the bonding process can be performed by diffusion bonding. In various embodiments, during the bonding process, the method further includes cooling the implant preform to a temperature suitable for preventing deformation of the polymer matrix.

[0010] In various embodiments, the method may further include machining the exposed surfaces of the upper and lower metal end plates to a depth that does not contact the corresponding non-porous metal sheet. In some embodiments, forming these grooves may further include machining the exposed surfaces of the upper and lower metal end plates to a depth that penetrates at least a portion of the corresponding non-porous metal sheet. In various embodiments, the step of forming these grooves may further include machining the implant blank to have at least one of the following shapes: a semi-circular shape, a semi-elliptical shape, a semi-oval shape, or a semi-teardrop shape.

[0011] In various embodiments, the step of forming these grooves may further include machining at least one exposed surface of the upper metal end plate or the lower metal end plate to a depth of about 0.25 mm to about 1.0 mm by performing multiple passes with a machining tool.

[0012] In various embodiments, the step of forming these grooves may further include machining the exposed surfaces of the upper and lower metal end plates to have a plurality of semi-teardrop-shaped grooves by performing multiple passes with a machining tool, each pass of the machining tool being oriented at an angle between about 30 degrees and about 60 degrees relative to the axis of the machining tool and the corresponding surface of the implant blank. In various embodiments, the step of forming these grooves may further include machining the exposed surfaces of the upper and lower metal end plates to form a plurality of teeth. In various embodiments, the step of forming the plurality of teeth may include machining the exposed surfaces of the upper and lower metal end plates to form a serrated configuration. In various embodiments, the step of forming the serrated configuration may include machining the exposed surfaces of the upper and lower metal end plates to a distance of about 1.0 mm to about 3.5 mm between the center or peak of the tooth.

[0013] In some embodiments, the injection molding process may further include a thermoplastic polymer selected from the group consisting of: polyetheretherketone, polyetherketoneketone, polyetherketone, carbon-polyetheretherketone composites, polyetheretherketone-BaSO4 polymer rubber, polyethylene terephthalate, and combinations thereof. In various embodiments, the bonding process of step (a) may further include porous and non-porous metal sheets selected from the group consisting of: titanium, titanium alloys, grade 5 titanium, hyperelastic titanium alloys, cobalt-chromium alloys, hyperelastic metal alloys, ceramics, stainless steel alloys, or combinations thereof. In other embodiments, following the anodizing step, the method may further include depositing nanoscale structures on the exposed surfaces of the upper and lower metal end plates. In various embodiments, the deposition step may include depositing nanorods, nanotubes, or nanowires formed from the oxide of the metal end plates.

[0014] Another aspect of this disclosure relates to an intervertebral implant formed by the methods disclosed above. The intervertebral implant may, for example, include an upper metal endplate and a lower metal endplate comprising a first plurality of porous metal sheets, a non-porous metal sheet, and a second plurality of porous metal sheets, wherein each of the upper and lower metal endplates may include grooves on its exposed surface configured to increase friction between the intervertebral implant and adjacent vertebral endplates, and a polymer body disposed between the upper and lower metal endplates, wherein the polymer body is at least partially impregnated within corresponding pore spaces on the first plurality of porous metal sheets of the upper metal endplate and corresponding pore spaces on the first plurality of porous metal sheets of the lower metal endplate.

[0015] In some embodiments, the interbody implant may include an upper metal endplate and a lower metal endplate, each comprising a first plurality of porous metal sheets bonded to a first side of the non-porous metal sheet and a second plurality of porous metal sheets bonded to a second side of the non-porous metal sheet opposite to the first side, thereby creating a solid barrier between the first plurality of porous metal sheets and the second plurality of porous metal sheets. In various embodiments, the polymer body of the interbody implant may include the group selected from: polyetheretherketone, polyetherketoneketone, polyetherketone, carbon-polyetheretherketone composites, polyetheretherketone-BaSO4 polymer rubber, polyethylene terephthalate, and combinations thereof. In various embodiments, the upper metal endplate and the lower metal endplate may each include the group selected from: titanium, titanium alloys, grade 5 titanium, superelastic titanium alloys, cobalt-chromium alloys, superelastic metal alloys, ceramics, stainless steel alloys, and combinations thereof.

[0016] In various embodiments, the grooves on the upper and lower metal end plates may have a semi-circular shape, a semi-elliptical shape, a semi-teardrop shape, or a combination thereof. In some embodiments, the upper and lower metal end plates may each include a plurality of teeth formed between the grooves on the exposed surfaces of the upper and lower metal end plates. In some embodiments, the distance between the centers of the teeth may be between about 1.0 mm and about 3.5 mm. In various embodiments, the depth of each groove may be between about 0.25 mm and about 1.0 mm.

[0017] Details of one or more aspects of this disclosure are set forth in the following drawings and description. Other features, objects, and advantages of the technology described in this disclosure will be apparent from the description, drawings, and claims. Attached Figure Description

[0018] Figure 1 This is a flowchart describing a method for manufacturing the intervertebral implant of the present invention.

[0019] Figure 2 This is a frontal perspective view of the intervertebral implant.

[0020] Figure 3 This is a rear perspective view of the intervertebral implant.

[0021] Figure 4 This is a top-down view of the intervertebral implant.

[0022] Figure 5A This is an exploded view of the metal endplate of an intervertebral implant.

[0023] Figure 5B This is a diagram of the exposed parts of a polymer intervertebral body implanted between vertebral bodies.

[0024] Figure 6 This is a side view of the intervertebral implant.

[0025] Figure 7 This is an enlarged perspective view of the nasal portion of the intervertebral implant.

[0026] Figure 8 It is an enlarged perspective view of the metal plate.

[0027] Figure 9 This is an enlarged perspective view of the metal end plate.

[0028] Figure 10 This is a front perspective view of a second example of an intervertebral implant.

[0029] Figure 11 This is a rear perspective view of a second example of an intervertebral implant.

[0030] Figure 12 This is a top-down perspective view of a second example of an interbody implant.

[0031] Figure 13 This is a side perspective view of a second example of an intervertebral implant.

[0032] Figure 14 This is a magnified perspective view of a portion of the second example of a metal endplate.

[0033] Figure 15 This is a perspective view of the third example of an intervertebral implant.

[0034] Figure 16 This is a top-down view of the intervertebral implant.

[0035] Figure 17 This is a rear perspective view of the third example of an intervertebral implant.

[0036] Figure 18 This is a side perspective view of the third example of an intervertebral implant.

[0037] Figure 19 A reference diagram depicting the human spine.

[0038] Figure 20 Reference diagrams depicting various anatomical planes of the human body. Detailed Implementation

[0039] The embodiments of this disclosure generally relate to, for example, spinal stabilization systems, and more specifically to, for example, implants used as spinal stabilization systems. Embodiments of the apparatus and methods are described below with reference to the accompanying drawings.

[0040] The following discussion omits or only briefly describes certain components, features, and functionalities related to medical implants, installation tools, and related surgical techniques, which will be apparent to those skilled in the art. It should be noted that various embodiments are described in detail with reference to the accompanying drawings, wherein, where possible, similar reference numerals denote similar parts and components in several views. Reference to the various embodiments does not limit the scope of the appended claims, as these embodiments are examples of the inventive concept described herein. Additionally, any examples set forth in this specification are intended to be non-limiting and illustrate some of the many possible embodiments applicable to the appended claims. Moreover, unless the context or other statements expressly indicate otherwise, specific features described herein may be used in combination with other described features in every possible combination and arrangement.

[0041] As used herein, the terms “same,” “equal,” “planar,” “coplanar,” “parallel,” and “perpendicular” are intended to cover exactly the same meaning, while also including possible variations, such as those resulting from manufacturing processes. The term “substantially” may be used herein to emphasize this meaning, particularly when the described embodiments have the same or substantially the same functionality or characteristics, unless otherwise expressly stated in the context or other statements. Furthermore, it should be understood that the term “about” covers variations of at least + / - 10% compared to the example values ​​provided herein.

[0042] The following discussion includes a description of, for example, interbody implants based on the principles of this disclosure and related methods for manufacturing interbody implants. Alternative embodiments are also disclosed. See the exemplary embodiments of this disclosure illustrated in the accompanying drawings for details. Figures 1 to 18 Examples of components of interbody implants, such as interbody implants 100, 200, or 300, are shown.

[0043] Various embodiments and components of the exemplary interbody implants disclosed herein can be manufactured from bioacceptable materials suitable for medical applications, including metals, synthetic polymers, ceramics, and bone materials and / or composites thereof. For example, components may be made individually or collectively from materials such as stainless steel alloys, commercially pure titanium, titanium alloys, grade 5 titanium, superelastic titanium alloys, cobalt-chromium alloys, superelastic metal alloys (e.g., Nitinol), and superelastic-plastic metals such as GUM METAL. ® ), ceramics and their complexes, such as calcium phosphate (e.g., SKELITE), ™Thermoplastics, such as polyaryletherketone (PAEK) (including polyetheretherketone (PEEK), polyetherketoneketone (PEKK), and polyetherketone (PEK)), carbon-PEEK composites, PEEK-BaSO4 polymer rubber, polyethylene terephthalate (PET), fabrics, silicone resins, polyurethanes, silicone-polyurethane copolymers, polymer rubbers, polyolefin rubbers, hydrogels, semi-rigid and rigid materials, elastomers, rubbers, thermoplastic elastomers, thermosetting elastomers, elastomer composites, rigid polymers (including polyphenylene, polyamide, polyimide, polyetherimide, polyethylene, epoxy resins), bone materials (including autologous grafts, allogeneic grafts, xenografts) Plant or transgenic cortical bone and / or corticomenal bone) and tissue growth or differentiation factors, partially reabsorbable materials (such as, for example, metal-calcium-based ceramic complexes, PEEK-calcium-based ceramic complexes, PEEK-reabsorbable polymer complexes), fully reabsorbable materials (such as, for example, calcium-based ceramics, such as calcium phosphate, tricalcium phosphate (TCP), hydroxyapatite (HA)-TCP, calcium sulfate), or other reabsorbable polymers, such as polyaetide, polyglycolic acid, polytyrosine carbonate, polycaprolactone, polylactic acid or polylactide, and combinations thereof.

[0044] Various embodiments and components may be coated with ceramic, titanium, and / or other biocompatible materials to provide, for example, micron- or nanometer-scale surface textures or structures. Similarly, components may undergo subtractive manufacturing processes to provide millimeter- or centimeter-scale surface textures or structures configured to promote bone integration and cell adhesion, as well as osteoblast maturation. Exemplary surface texturing or structuring of additive and subtractive manufacturing processes may include features such as grooves with a depth of about 0.25 mm to about 1.0 mm on at least one exposed surface of an upper or lower end plate, and nanoscale structures such as nanorods, nanotubes, or nanowires with an average diameter of about 35 nm to about 85 nm, about 50 nm to about 70 nm, or about 55 nm to about 60 nm and an average length of at least about 10 nm. In various embodiments, for example, structural features may overlap each other. Furthermore, such surface texturing can be applied to any surface, for example, both the external exposed surface of the component and the internal non-exposed surface of the component.

[0045] Suitable subtractive techniques for producing surface structures / features may include, for example, machining (e.g., machining tools such as saws, lathes, milling machines, machines, drills, electrical discharge machining (EDM)) to physically remove material to achieve the desired geometry and dimensions of the groove structure. The desired structure can be formed by performing multiple passes at various angles with a machining tool to achieve the desired geometry configured for optimal insertion and to provide friction to improve resistance to migration in the installed state. Based on the desired structural geometry and parameters, suitable additive techniques for producing the desired surface structure may include, for example, 3D printing, injection molding, or deposition. Further discussion of exemplary surface texturing is described, for example, in U.S. Patent No. 11,096,796, filed March 4, 2013, entitled “Interbody spinal implant having a roughened surfacetopography on one or more internal surfaces,” the entire disclosure of which is incorporated herein by reference. Therefore, it should be understood that any texturing process described in U.S. Patent No. 11,096,796 can be applied to any component of the various embodiments disclosed herein, such as the exposed and internal surfaces of end plates.

[0046] Following the formation of the grooves or structures, additional surface treatment steps can be applied to create or deposit nanostructures on the outermost surface of the intervertebral body. Nanostructures can also be formed by subtractive mechanical and chemical techniques (e.g., machining or chemical etching) or additive techniques (e.g., surface deposition of nanostructured oxide nanoscale structures such as, for example, nanorods, nanotubes, or nanowires on a metal surface). This surface treatment provides a protective layer that offers corrosion resistance, protection against abrasion and tearing, and improves the biological response during bone healing. In various embodiments, anodizing of the outermost metal surface can be applied prior to the surface treatment of the metal endplate.

[0047] Overall Reference Figure 1 The method used for manufacturing was disclosed. Figures 2 to 18 Flowcharts for various interbody vertebral implant implementation schemes. (Overall reference) Figure 2 Figure 5 shows various views of the intervertebral implant 100. Figure 2 and Figure 3 An example is shown: a front perspective view and a rear perspective view of the implant 100, and... Figure 4 A top-down view of implant 100 is shown.

[0048] exist Figure 1In the first step 101, forming a metal endplate may be included by a diffusion bonding process. This step may include forming an upper metal endplate and a lower metal endplate respectively by bonding a plurality of porous metal sheets to a non-porous metal sheet. An exemplary bonding process may be a diffusion bonding process. The exposed surfaces of the endplates may be porous for adhesion to polymers or other materials in subsequent steps. The second step 102 may include forming a polymer body or core of the intervertebral implant. In various embodiments, this step may include injection molding a thermoplastic polymer between a lower surface of the upper metal endplate 10S and an upper surface of the lower metal endplate 10I. The thermoplastic polymer may flow into the pore spaces of the upper and lower metal endplates and connect these components together. After forming the polymer body between the metal endplates, a subsequent step 103 may include forming microscale grooves on the surfaces of the upper metal endplate 10S and the lower metal endplate 10I by machining. The machining process may be performed, for example, by a subtractive manufacturing process that includes machining tools such as saws, lathes, deburrs, milling cutters, and drilling machines. After forming the groove, step 104 may include applying a surface treatment to form a nanoscale structure on the surface of the metal endplate. An exemplary surface treatment process may be electrochemical anodizing to form metal oxide nanotubes. Surface treatment step 104 may promote biological responses, such as bone inward growth or fusion. Given... Figures 2 to 18 The detailed description of the device implementation shown allows for the use and / or modification of various steps and methods. Figure 1 The steps described herein should be understood in the context of the description of the manufactured implant, which is described in detail below.

[0049] Figure 5A and Figure 5B An exploded view of the implant 100 is shown, which includes an upper metal endplate 10S and a lower metal endplate 10I. Figure 5A ) and polymer body 20 ( Figure 5B In an exemplary embodiment, the implant 100 may be formed of a first component including metal endplates 10 and a second component including a polymer body 20 (also referred to as a polymer core) disposed between the metal endplates 10. In various embodiments, the metal endplates 10 may include an upper metal endplate 10S and a lower metal endplate 10I. In various embodiments, the polymer body 20 may be produced by injection molding a thermoplastic polymer between a lower surface of the upper metal endplate 10S and an upper surface of the lower metal endplate 10I. In some embodiments, the thermoplastic polymer used to produce the polymer core may include polyetheretherketone (PAEK), polyetherketoneketone (PEEK), polyetherketone (PEKK), carbon-polyetheretherketone composites, polyetheretherketone-BaSO4 polymer rubber, polyethylene terephthalate (PET), or combinations thereof.

[0050] refer to Figure 4The implant 100 may extend from the proximal end 100P to the distal end 100D along the longitudinal axis AA in a proximal-to-distal direction. Additionally, the implant 100 may extend along the lateral axis BB between the first lateral end 100L and the second lateral end 100L in the width direction. In various embodiments, the cross-sectional geometry of the intervertebral implant 100 may have various configurations, such as cylindrical, circular, oval, elliptical, triangular, polygonal with planar or arcuate sides, irregular, uniform, non-uniform, consistent, variable, horseshoe-shaped, U-shaped, or bean-shaped.

[0051] like Figure 2 and Figure 3 As best seen, the metal endplate 10 may include a first opening 15, and the polymer body 20 may include a second opening 22 aligned with and adjacent to the first opening 15. In this embodiment, the openings 15, 22 may be configured to receive a medicament, which may include a bone graft (not shown) and / or other materials for fixation or fusion treatment. Furthermore, as Figure 2 and Figure 3 As seen in, and in Figure 9 As explained in more detail below, the metal end plate 10 may include a plurality of holes 16 along the surface of the metal end plate 10. In various embodiments, the metal end plate 10 may include a plurality of grooves 14.

[0052] like Figure 2 As best viewed from within, the interbody implant 100 may include various contours and / or features to facilitate posterior insertion of the implant 100 into the patient's body. In an exemplary embodiment, the proximal end 100P of the interbody implant 100 may include a gripping notch 21 and a threaded hole 25. In use, a surgeon may grip the implant 100 at the gripping notch 21 using a surgical instrument, and / or grip it, for example, by threading a surgical instrument (not shown) into the threaded hole 25.

[0053] refer to Figure 5A and Figure 5B Upper metal end plate 10S and lower metal end plate 10I ( Figure 5A ) can be through polymer body 20 ( Figure 5B The components are interconnected to form independent structures for the implant blank. In various embodiments, the upper end plate 10S and the lower metal end plate 10I may extend in a proximal-to-distal direction, having a proximal end 10P and a distal end 10D. The lower surface of the upper metal end plate 10S and the upper surface of the lower metal end plate 10I may contact the upper and lower surfaces of the polymer body 20 and may be stabilized by an injection molding process to prevent disassembly. (Reference) Figure 5B The polymer body 20 extends in a proximal-to-distal direction and has a proximal end 20P and a distal end 20D. (See below...) Figure 9As further explained, in various embodiments, the lower surface of the upper metal end plate 10S and the upper surface of the lower metal end plate 10I in contact with the polymer body 20 may be configured to include holes 16 for the injected thermoplastic polymer to occupy, harden, and grip.

[0054] Figure 6 This is a side perspective view of the interbody implant 100. In various embodiments, the interbody implant 100 may extend longitudinally from a proximal end portion 100P to a distal end portion 100D. The interbody implant 100 may include an angled nasal portion 26 at the distal end portion 20D, configured for posterior insertion of the interbody implant. In various embodiments, the interbody implant may include a plurality of grooves 14 on the outer surfaces of metal endplates 10S and 10I. Reference Figure 7 An enlarged perspective view of the nasal portion 26 at the distal end 20D is shown. In some embodiments, the nasal portion may be configured at an angle β relative to the longitudinal axis of the intervertebral implant to provide a desired tilt for insertion of the implant via a linear impact. In various embodiments, the angle β may be about 25 degrees to about 60 degrees, about 25 degrees to about 45 degrees, or about 30 degrees to about 40 degrees, about 40 degrees to about 50 degrees, or about 45 degrees to about 60 degrees. In various embodiments, the nasal portion 26 may be formed by machining an implant blank using machining tools such as saws, lathes, deburring machines, milling machines, and drilling machines. In some embodiments, a gripping notch 21 and a threaded hole 25 are present at the proximal end 100P of the implant. Figure 3 (As shown) can be formed by machining an implant blank from machining tools such as saws, lathes, deburrs, milling machines and drilling machines.

[0055] Now for reference Figure 8 The image shows an enlarged perspective view of the metal endplate 10. In various embodiments, the metal endplate may include a series of grooves 14 configured to increase friction between the intervertebral implant 100 and the patient's bone anatomy and to prevent migration of the implant 100 after installation. In various embodiments, the grooves 14 may be formed by subtractive machining steps including at least one of: electrical discharge machining, milling, lathe machining, deburring, sawing, or sanding. In various embodiments, subtractive machining may be performed to achieve a groove depth D ranging from about 0.25 mm to about 1.0 mm, about 0.50 mm to about 0.75 mm, about 0.55 mm to about 0.70 mm, or about 0.60 mm to about 0.65 mm. In some embodiments, the grooves 14 may be machined to have at least one of: a semi-circular shape, a semi-elliptical shape, a semi-oval shape, or a semi-teardrop shape. In various embodiments, asymmetrical shapes may be formed by performing multiple passes with a machining tool, such as... Figure 8The illustrated semi-teardrop shape is oriented at an angle relative to the axis of the machining tool and the corresponding surface of the implant blank. In various embodiments, the groove may be constructed at an angle α on one side of the groove and have sharp edges provided on the opposite side of the groove to prevent the intervertebral implant from retracting. In some embodiments, the angle α is from about 30 degrees to about 60 degrees. In various embodiments, the distance (L) between the groove 14 and the adjacent groove 14 may be from about 0.25 mm to about 1.5 mm, from about 0.50 mm to about 1.25 mm, or from about 0.75 mm to about 1.0 mm.

[0056] In various embodiments, the groove 14 may be machined to form a plurality of teeth that may be referred to as a serrated configuration. In various embodiments, the metal end plate 10 may be machined such that the distance between the centers (or peaks) of the teeth in the serrated configuration may be about 1.0 mm to about 3.5 mm, about 1.5 mm to about 3.0 mm, about 2.0 mm to about 2.5 mm, about 1.0 mm to about 1.7 mm, about 1.7 mm to about 2.5 mm, or about 2.5 mm to about 3.5 mm.

[0057] refer to Figure 9 The image shows an enlarged perspective view of a portion of the metal endplate. In various embodiments, the upper metal endplate 10S or the lower metal endplate 10I may include a first plurality of porous metal sheets 11 in contact with the upper and lower surfaces of the polymer body 20, a second plurality of porous metal sheets 13 including the exposed surface of the intervertebral implant 100, and a non-porous metal sheet 12 disposed between the first plurality of porous metal sheets 11 and the second plurality of porous metal sheets 13. In various embodiments, the metal sheets 11, 12, and 13 are bonded by a diffusion bonding process. In various embodiments, the non-porous metal sheet 12 is disposed between the porous metal sheets 11 and 13 to prevent thermoplastic polymer from flowing from the first plurality of porous metal sheets 11 into the second plurality of porous metal sheets 13 during the injection molding process.

[0058] In various embodiments, the first plurality of porous metal sheets 11 may comprise one to two individual porous metal sheets. It should be understood that any number of porous metal sheets 11 is contemplated depending on the desired thickness. In some embodiments, the second plurality of porous metal sheets 13 may comprise two to three individual porous metal sheets. It should be understood that any number of porous metal sheets 13 is contemplated depending on the desired thickness. In some embodiments, the individual porous metal sheets and the non-porous metal sheets 12 may each be about 0.20 mm to about 0.30 mm thick. In some embodiments, the plurality of porous metal sheets 11 and 13 are configured such that a majority of the holes 16 of the adjacent stacked porous metal sheets are offset from each other. This offset configuration facilitates the bonding process. In various embodiments, the plurality of porous metal sheets 11 and 13 may each comprise about 45% to about 70%, about 50% to about 65%, or about 55% to about 60% of volume voids, i.e., how much of the total volume is empty space or air.

[0059] In some embodiments, the second plurality of porous metal sheets 13 may be machined to form grooves. In various embodiments, the machining process may include machining the second plurality of porous metal sheets 13 to a depth that does not contact the corresponding non-porous metal sheet 12. In various embodiments, the machining process may include machining the second plurality of porous metal sheets 13 to a depth that passes through at least a portion of the corresponding non-porous metal sheet 12. In various embodiments, the non-porous metal sheet 12 may provide a barrier to the first plurality of porous metal sheets 11 in contact with the polymer body 20, such that the machining process does not extend to the first plurality of porous metal sheets 11. In this way, the polymer body 20 will not migrate from the holes 16 of the first plurality of porous metal sheets 11 to the holes 16 on the second plurality of porous metal sheets 13. In various embodiments, during the machining process, the intervertebral implant may be cooled to a temperature suitable for preventing deformation of the polymer body 20 and detachment from the metal endplate 10.

[0060] After machining the grooves, a surface treatment can be applied to the surface of the metal endplate 10 to further protect the surface from corrosion, abrasion, and tearing, and to improve the biological response during bone healing. For example, the surface treatment can promote bone growth. In various embodiments, the surface treatment may include anodizing the surface of the metal endplate to produce a metal oxide of the metal endplate. For example, a metal endplate formed of titanium can form nanoscale titanium oxide nanostructures, such as nanorods, nanotubes, and nanowires. In various embodiments, the diameter of the nanoscale structure may be from about 35 nm to about 85 nm, from about 50 nm to about 70 nm, or from about 55 nm to about 60 nm. In addition, the nanoscale structure may have an average length of at least about 10 nm.

[0061] Figure 10 and Figure 11 These are, respectively, front and rear perspective views of a second example of an interbody implant 200 that can be manufactured by the methods described in this disclosure. The implant 200 may have the same, similar, and / or substantially the same features and functions as described above with respect to the interbody implant 100. For example, the interbody implant 200 may include an upper metal endplate 30 and a polymer body 40 disposed between the upper metal endplate 30S and the lower metal endplate 30I. Figure 10 and Figure 11 As best viewed, the metal endplate 30 may include a first opening 35, and the polymer body 40 may include a second opening 42 aligned with and adjacent to the first opening 35. In this embodiment, the openings 35, 42 may be configured to receive a medicament, which may include a bone graft (not shown) and / or other materials for fixation or fusion treatment. Furthermore, as Figure 10 and Figure 11 As seen, the metal endplate 30 may include a plurality of holes 36 along the surface of the endplate 30. In various embodiments, the metal endplate 30 may include a plurality of recesses 34. In this embodiment, the proximal end portion 200P of the intervertebral implant 200 may include a gripping notch 41 and a threaded hole 45 for, for example, threaded engagement of surgical instruments. Reference Figure 12 The implant 200 may extend from the proximal end 200P to the distal end 200D along the longitudinal axis AA in a proximal to distal direction. In addition, the implant 200 may extend along the axis CC between the first lateral end 200L and the second lateral end 200L in the width direction.

[0062] In this embodiment, the interbody implant 200 may include a blunt nasal portion 46 at the distal end 200D. For example... Figure 12 and Figure 13 As seen in the top-down and side perspective views, the dolphin nose portion 46 can be designed in a way that eliminates the need for impact insertion techniques used in implants that do not include such a dolphin nose portion 46 or similar structures. In this configuration, the intervertebral implant 200 can be configured to be inserted posteriorly along the AABB plane into the surgical area, and then rotated about the AA axis to allow the groove 34 to contact the bone and be oriented to inhibit migration. Additionally... Figure 14 An enlarged perspective view of a portion of a second example of the metal end plate 30 is shown. Figure 14 In the exemplary configuration, the groove 34 is machined into a semi-circular shape having a depth corresponding to the radius R of the semi-circular groove.

[0063] Figure 15 and Figure 16These are perspective and top-down views, respectively, of a third exemplary interbody implant 300 manufactured using the methods described in this disclosure. The implant 300 may have the same, similar, and / or substantially the same features and functions as described above with respect to interbody implants 100 and 200. Figure 15 As best viewed in the present invention, the interbody implant 300 may include a first opening 55, and the polymer body 60 may include a second opening 62 aligned with and adjacent to the first opening 55. In this embodiment, openings 55, 62 may be configured to receive a medicament, which may include a bone graft (not shown) and / or other materials, for fixation or fusion treatment. Reference Figure 16 The implant 300 may extend from a proximal end 300P to a distal end 300D along the longitudinal axis AA in a proximal-to-distal direction. Additionally, the implant 300 may extend along the lateral axis BB between a first lateral end 300L and a second lateral end 300L in the width direction. In this embodiment, the interbody implant 300 may include two threaded holes 65 and 66 for use with an inserter tool (not shown) for laterally inserting the interbody implant 300 into the surgical area. Figure 17 As shown, the interbody implant can have a non-uniform conical geometry, having a first height H1 at one lateral side 300L and a second height H2 at the opposite lateral side 300L. Figure 18 This is a side perspective view from the shorter side, showing the groove 54 and hole 56 on the upper metal end plate 50S and the lower metal end plate 50I.

[0064] Figure 19 This is a reference diagram illustrating various publicly disclosed implant implementations that can be installed in the human spine. (Example) Figure 19 The human spine, as depicted, consists of a cluster of 33 curved vertebrae structurally divided into five regions: the cervical region (C1-C7), the thoracic region (T1-T12), the lumbar region (L1-L5), and the fused sacral and coccygeal region. Towards the base of the spine, the vertebrae are larger because the spine supports the heavier loads of the body in this region. The cervical vertebrae, forming the neck region, are relatively smaller to improve head flexibility and because they support less load compared to the thoracic and lumbar regions. Directly below the cervical vertebrae are the thoracic vertebrae, which form the upper back. The thoracic vertebrae are larger than the cervical vertebrae, increasing in size from top to bottom. Below the thoracic region are the lumbar vertebrae, which are even larger and support the weight of the entire upper body. Relative movement within the spine also varies along its length, as the cervical vertebrae have a greater range of motion than the lower lumbar vertebrae. Figure 20The disclosed implant implementation schemes are reference diagrams showing various planes and reference directions in which the patient can move or act.

[0065] It should be understood that the various aspects disclosed herein can be combined with combinations different from those specifically presented in the specification and figures. For example, unless the context clearly indicates otherwise, a feature, function, or component from one embodiment can be combined with another embodiment, and vice versa. Similarly, unless the context clearly indicates otherwise, features, functions, and components may be omitted. It should also be understood that, depending on the example, certain actions or events in any of the processes or methods described herein may be performed in a different order, or may be completely added, combined, or omitted (e.g., performing these techniques may not require all the described actions or events).

[0066] Unless otherwise specifically defined herein, all terms shall be interpreted as broadly as possible, including their implied meaning from the specification and their meaning as understood by those skilled in the art and / or as defined in dictionaries, papers, etc. It must also be noted that, unless otherwise specified, the singular forms “a,” “an,” and “the” used in the specification and appended claims include plural referents, and the terms “comprises” and / or “comprising” as used in this specification indicate the presence of stated features, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0067] Without excluding other possible implementations, certain exemplary implementations are outlined in the following example clauses: Clause 1: A method of manufacturing an intervertebral implant having a metal endplate and a polymer body, the method comprising the steps of: (a) bonding a first plurality of porous metal sheets to a first side of a non-porous metal sheet and bonding a second plurality of porous metal sheets to a second side of the non-porous metal sheet opposite to the first side by applying a bonding process, the non-porous metal sheet creating a solid barrier between the first plurality of porous metal sheets and the second plurality of porous metal sheets, thereby forming an upper metal endplate and a lower metal endplate, respectively; (b) forming a polymer body by injection molding a thermoplastic polymer between a lower surface of the upper metal endplate and an upper surface of the lower metal endplate, the injection molding of the thermoplastic polymer impregnating corresponding pore spaces on the first plurality of porous metal sheets of the upper metal endplate and corresponding pore spaces on the first plurality of porous metal sheets of the lower metal endplate, thereby producing an implant blank; and (c) forming grooves on the implant blank by applying a machining process to the exposed surfaces of the upper metal endplate and the lower metal endplate.

[0068] Clause 2: According to the method of Clause 1, after the machining process in step (c), the method further includes (d) applying an anodizing step to the exposed surfaces of the upper metal end plate and the lower metal end plate.

[0069] Clause 3: The method according to Clause 1 or Clause 2, wherein the machining in step (c) is performed by a subtractive machining step, the subtractive machining step including at least one of the following: milling, lathe machining, deburring, sawing, or sanding.

[0070] Clause 4: The method according to any one of the preceding clauses, wherein during the injection molding process in step (b), each non-porous metal sheet prevents the thermoplastic polymer from flowing from the first plurality of porous metal sheets into the second plurality of porous metal sheets.

[0071] Clause 5: The method according to any one of the preceding clauses, wherein a porous metal sheet and a non-porous metal sheet, each being about 0.20 mm to about 0.30 mm thick, are combined.

[0072] Clause 6: The method according to any one of the preceding clauses, wherein the bonding process in step (a) includes stacking a plurality of porous metal sheets such that a majority of the corresponding pores of adjacent stacked porous metal sheets are offset from each other, wherein the plurality of porous metal sheets contain about 45% to about 70% by volume of voids.

[0073] Clause 7: The method according to any one of the preceding clauses, wherein the bonding process in step (a) is carried out by diffusion bonding.

[0074] Clause 8: The method according to any one of the preceding clauses further comprises: cooling the implant blank to a temperature suitable for preventing deformation of the polymer body during the machining process.

[0075] Clause 9: The method according to any one of the preceding clauses, wherein forming the groove further comprises: machining the exposed surfaces of the upper metal end plate and the lower metal end plate to a depth that does not contact the corresponding non-porous metal sheet.

[0076] Clause 10: The method according to Clause 9, wherein the step of forming the groove further comprises: machining the exposed surfaces of the upper metal end plate and the lower metal end plate to a depth passing through at least a portion of the corresponding non-porous metal sheet.

[0077] Clause 11: The method according to any one of the preceding clauses, wherein the step of forming the groove further comprises machining the implant blank into having at least one of the following shapes: a semi-circular shape, a semi-elliptical shape, a semi-oval shape, or a semi-teardrop shape.

[0078] Clause 12: The method according to Clause 11, wherein the step of forming the groove further comprises: machining at least one exposed surface of the upper metal end plate or the lower metal end plate to a depth of about 0.25 mm to about 1.0 mm by performing multiple passes with a machining tool.

[0079] Clause 13: The method according to Clause 11, wherein the step of forming the groove further comprises: machining the exposed surfaces of the upper metal end plate and the lower metal end plate to have a plurality of semi-teardrop grooves by performing multiple passes with a machining tool, each pass of the machining tool being oriented at an angle between about 30 degrees and about 60 degrees relative to the axis of the machining tool and the corresponding surface of the implant blank.

[0080] Clause 14: The method according to any one of the preceding clauses, wherein the step of forming the groove further comprises: machining the exposed surfaces of the upper metal end plate and the lower metal end plate to form a plurality of teeth.

[0081] Clause 15: The method according to Clause 14, wherein the step of forming the plurality of teeth comprises: machining the exposed surfaces of the upper metal end plate and the lower metal end plate to form a serrated configuration.

[0082] Clause 16: The method according to Clause 15, wherein the step of forming the sawtooth configuration comprises: machining the exposed surfaces of the upper metal end plate and the lower metal end plate to a distance of about 1.0 mm to about 3.5 mm between the centers of the teeth.

[0083] Clause 17: The method according to any one of the preceding clauses, wherein the injection molding process further comprises a thermoplastic polymer selected from the group consisting of: polyetheretherketone, polyetherketoneketone, polyetherketone, carbon-polyetheretherketone composites, polyetheretherketone-BaSO4 polymer rubber, polyethylene terephthalate, and combinations thereof.

[0084] Clause 18: The method according to any one of the preceding clauses, wherein the bonding process of step (a) further comprises selecting porous metal sheets and non-porous metal sheets from the group consisting of: titanium, titanium alloys, grade 5 titanium, superelastic titanium alloys, cobalt-chromium alloys, superelastic metal alloys, ceramics, stainless steel alloys, or combinations thereof.

[0085] Clause 19: The method according to Clause 2, after the anodizing step, further comprises: depositing a nanoscale structure on the exposed surfaces of the upper metal end plate and the lower metal end plate.

[0086] Clause 20: The method according to Clause 19, wherein the deposition step comprises: depositing nanorods, nanotubes or nanowires formed from the oxide of the metal endplate.

[0087] Clause 21: An intervertebral implant formed by a manufacturing method according to any one of the preceding clauses.

[0088] Clause 22: An intervertebral implant comprising: an upper metal endplate and a lower metal endplate, the upper metal endplate and the lower metal endplate respectively comprising a first plurality of porous metal sheets, a non-porous metal sheet and a second plurality of porous metal sheets, wherein the upper metal endplate and the lower metal endplate each include a groove on their exposed surfaces, the groove being configured to increase friction between the intervertebral implant and adjacent vertebral endplates; and a polymer body disposed between the upper metal endplate and the lower metal endplate, wherein the polymer body is at least partially impregnated within corresponding pore spaces on the first plurality of porous metal sheets of the upper metal endplate and corresponding pore spaces on the first plurality of porous metal sheets of the lower metal endplate.

[0089] Clause 23: The intervertebral implant according to Clause 22, wherein the upper metal endplate and the lower metal endplate each include a first plurality of porous metal sheets bonded to a first side of the non-porous metal sheet and a second plurality of porous metal sheets bonded to a second side of the non-porous metal sheet opposite to the first side of the non-porous metal sheet, thereby creating a solid barrier between the first plurality of porous metal sheets and the second plurality of porous metal sheets.

[0090] Clause 24: Intervertebral implants pursuant to Clause 22 or Clause 23, wherein the polymer body comprises a thermoplastic polymer selected from the group consisting of: polyetheretherketone, polyetherketoneketone, polyetherketone, carbon-polyetheretherketone composites, polyetheretherketone-BaSO4 polymer rubber, polyethylene terephthalate, and combinations thereof.

[0091] Clause 25: An interbody implant according to any one of Clauses 22 to 24, wherein the upper metal endplate and the lower metal endplate each comprise titanium, titanium alloy, grade 5 titanium, superelastic titanium alloy, cobalt-chromium alloy, superelastic metal alloy, ceramic, stainless steel alloy, and combinations thereof selected from the group consisting of titanium, titanium alloy, grade 5 titanium, superelastic titanium alloy, cobalt-chromium alloy, superelastic metal alloy, ceramic, stainless steel alloy, and combinations thereof.

[0092] Clause 26: An intervertebral implant according to any one of Clauses 22 to 25, wherein the recess has a semi-circular shape, a semi-elliptical shape, a semi-teardrop shape, or a combination thereof.

[0093] Clause 27: An intervertebral implant according to any one of Clauses 22 to 26, wherein the upper metal endplate and the lower metal endplate each include a plurality of teeth formed between the grooves on the exposed surfaces of the upper metal endplate and the lower metal endplate.

[0094] Clause 28: The intervertebral implant as described in Clause 27, wherein the distance between the centers of the teeth is about 1.0 mm to about 3.5 mm.

[0095] Clause 29: An intervertebral implant according to any one of Clauses 22 to 28, wherein the depth of each groove in the groove is about 0.25 mm to about 1.0 mm.

Claims

1. A method for manufacturing an intervertebral implant (100) having a metal endplate (10) and a polymer body (20), the method comprising the following steps: (a) By applying a bonding process to bond a first plurality of porous metal sheets (11) to a first side of a non-porous metal sheet (12) and to bond a second plurality of porous metal sheets (13) to a second side of the non-porous metal sheet opposite to the first side, the non-porous metal sheet creates a solid barrier between the first plurality of porous metal sheets and the second plurality of porous metal sheets, thereby forming an upper metal end plate (10S) and a lower metal end plate (10I), respectively. (b) A polymer body is formed by injection molding a thermoplastic polymer between the lower surface of the upper metal end plate and the upper surface of the lower metal end plate, wherein the injection molding of the thermoplastic polymer impregnates the corresponding pore spaces (16) on the first plurality of porous metal sheets of the upper metal end plate and the corresponding pore spaces on the first plurality of porous metal sheets of the lower metal end plate, thereby producing an implant blank; as well as (c) A groove (14) is formed on the implant blank by applying a machining process to the exposed surfaces of the upper metal end plate and the lower metal end plate.

2. The method according to claim 1, further comprising, after the machining process in step (c), (d) applying an anodizing step to the exposed surfaces of the upper metal end plate and the lower metal end plate.

3. The method according to claim 1 or claim 2, wherein the machining in step (c) is performed by a subtractive machining step, the subtractive machining step comprising at least one of the following: milling, deburring lathe machining, sawing, or sanding.

4. The method according to any one of the preceding claims, wherein a porous metal sheet and a non-porous metal sheet, each having a thickness of about 0.20 mm to about 0.30 mm, are combined.

5. The method according to any one of the preceding claims, wherein the bonding process in step (a) is carried out by diffusion bonding.

6. The method according to any one of the preceding claims, wherein forming the groove further comprises: The exposed surfaces of the upper metal end plate and the lower metal end plate are machined to a depth that does not contact the corresponding non-porous metal sheet.

7. The method according to any one of the preceding claims, wherein the step of forming the groove further comprises machining the implant blank into having at least one of the following shapes: a semi-circular shape, a semi-elliptical shape, a semi-oval shape, or a semi-teardrop shape.

8. The method of claim 7, wherein the step of forming the groove further comprises: At least one exposed surface of the upper metal end plate or the lower metal end plate is machined to a depth of about 0.25 mm to about 1.0 mm by performing multiple passes with a machining tool.

9. The method according to any one of the preceding claims, wherein the step of forming the groove further comprises: The exposed surfaces of the upper metal end plate and the lower metal end plate are machined to form multiple teeth.

10. The method of claim 2, wherein after the anodizing step, the method further comprises: Nanoscale structures are deposited on the exposed surfaces of the upper and lower metal end plates.

11. An interbody implant, the interbody implant comprising: The upper metal endplate and the lower metal endplate respectively include a first plurality of porous metal sheets, a non-porous metal sheet and a second plurality of porous metal sheets, wherein the upper metal endplate and the lower metal endplate each include a groove on their exposed surface, the groove being configured to increase friction between the intervertebral implant and the endplate of the adjacent vertebral bone; and A polymer body is disposed between the upper metal end plate and the lower metal end plate, wherein the polymer body is at least partially immersed in corresponding pore spaces on the first plurality of porous metal sheets of the upper metal end plate and corresponding pore spaces on the first plurality of porous metal sheets of the lower metal end plate.

12. The intervertebral implant of claim 11, wherein the upper metal endplate and the lower metal endplate each comprise a first plurality of porous metal sheets bonded to a first side of the non-porous metal sheet and a second plurality of porous metal sheets bonded to a second side of the non-porous metal sheet opposite to the first side of the non-porous metal sheet, thereby creating a solid barrier between the first plurality of porous metal sheets and the second plurality of metal sheets.

13. The intervertebral implant according to claim 11 or claim 12, wherein the groove has a semi-circular shape, a semi-elliptical shape, a semi-teardrop shape, or a combination thereof.

14. The intervertebral implant according to any one of claims 11 to 13, wherein the upper metal endplate and the lower metal endplate each include a plurality of teeth formed between the grooves on the exposed surfaces of the upper metal endplate and the lower metal endplate, wherein the centers of the teeth are spaced about 1.0 mm to about 3.5 mm apart.

15. The intervertebral implant according to any one of claims 11 to 14, wherein the depth of each groove in the groove is about 0.25 mm to about 1.0 mm.

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