Polymer interbody device with metal endcaps and endplate grooves and manufacturing method thereof

Abstract

Interbody implants formed by disposing a polymeric body between superior and inferior metallic endplates and the methods of forming the implants are disclosed. In some embodiments, the interbody implant comprises a plurality of porous and non-porous metallic sheets that are bonded to form metallic endplates. In various embodiments, a polymeric body may be infilled between the superior metallic endplate and inferior metallic endplate by an injection molding process. In various embodiments, the metallic endplates may comprise a plurality of grooves produced by a subtractive manufacturing process. In various embodiments, the metallic endplates may further comprise providing a surface treatment to produce nanoscale metallic oxide nanostructures.

Description

POLYMER INTERBODY DEVICE WITH METAL ENDCAPS AND ENDPLATE GROOVES AND MANUFACTURING METHOD THEREOF

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 591,285, filed October 18, 2023, the entire content of which is incorporated herein by reference.CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application incorporates by reference: U.S. Pat. No. 11,717,422, titled Spinal Implant System and Method, and filed on May 14, 2021; U.S. Pat. No. 11,096,796, titled Interbody spinal implant having a roughened surface topography on one or more internal surfaces, and filed on March 4, 2013; and U.S. Pat. No. 10,821,000, titled Titanium implant surfaces free from alpha case and with enhanced osteoinduction, and filed June 29, 2017. The entire disclosure of each of the above documents is incorporated herein by reference in its entirety.FIELD

[0003] The present technology is generally related to methods of manufacturing surgical implants and methods of using surgical implants and devices for insertion in the human body.BACKGROUND

[0004] Spinal pathologies and disorders such as degenerative disc disease, disc herniation, osteoporosis, spondylolisthesis, stenosis, rumor, scoliosis and other curvature abnormalities, kyphosis and fracture may result from factors including trauma, disease and degenerative conditions caused by injury and aging. Spinal disorders typically result in symptoms including deformity, pain, nerve damage, and partial or complete loss of mobility.

[0005] Non-surgical treatments, such as medication, rehabilitation and exercise can be effective, however, may fail to relieve the symptoms associated with these disorders. Surgical treatment of these spinal disorders includes, for example, fusion, fixation, correction, partial or complete discectomy, corpectomy and laminectomy, and implantableprosthetics. As part of these surgical treatments, spinal constructs, such as, for example, bone fasteners, spinal rods and interbody devices can be used to provide stability to a treated region. For example, during surgical treatment, interbody implants can be delivered to a surgical site for fixation with bone to immobilize a joint. This disclosure describes an improvement over these technologies.SUMMARY

[0006] The techniques of this disclosure generally relate to manufacturing of, for example, an interbody implant with metallic endplates and a polymeric body. In one aspect, the method may comprise: (a) forming a superior metallic endplate and an inferior metallic endplate, respectively, by applying a bonding process to bond a first plurality of porous metallic sheets to a first side of a non-porous metallic sheet and to bond a second plurality of porous metallic sheets to a second side of the non-porous metallic sheet opposite the first side the non-porous metallic sheet creating a solid barrier between the first plurality of porous metallic sheets and the second plurality of porous metallic sheets; (b) forming a polymeric body by injection molding a thermoplastic polymer between a lower surface of the superior metallic endplate and an upper surface of the inferior metallic endplate, the injection molding of the thermoplastic polymer impregnating corresponding pore spaces on the first plurality of porous metallic sheets of the superior metallic endplate and corresponding pore spaces on the first plurality of porous metallic sheets of the inferior metallic endplate thereby producing an implant blank; and (c) forming grooves on the implant blank by applying a machining process to exposed surfaces of the superior metallic endplate and the inferior metallic endplates.

[0007] In various embodiments, after the machining process in step (c), the method may further comprise, (d) an anodization step to the exposed surfaces of the superior metallic endplate and the inferior metallic endplate. In some embodiments, the machining in step (c) may further comprise subtractive mechanical processing step comprising at least one of: electrical discharge machining, milling, lathing, burring sawing, or sanding. In some embodiments, during the injection molding process of step (b), each non-porous metallic sheet may prevent the thermoplastic polymer from flowing from the first plurality of porous metallic sheets into the second plurality of porous metallic sheet.

[0008] In some embodiments, the bonding of a porous metallic sheet and a non-porous metallic sheet may be between about 0.20 mm to about 0.30 mm thick. In variousembodiments, the bonding process in step (a) may comprise stacking a plurality of porous metallic sheets such that a majority of respective pores of adjacently stacked porous metallic sheets are offset from each other, wherein the plurality of porous metallic sheet may comprise about 45% to about 70% volume % void. In some embodiments, the bonding process may be conducted by diffusion bonding. In various embodiments, during the bonding process, the method further comprises cooling the implant blank to a temperature suitable to prevent the polymeric body from deforming.

[0009] In various embodiments, the method may further comprise machining the exposed surface of the superior and the inferior metallic endplates to a depth that does not contact the corresponding non-porous metallic sheet. In some embodiments, the forming the grooves may further comprise machining the exposed surface of the superior and the inferior metallic endplates to a depth that passes through at least a portion of the corresponding non-porous metallic sheet. In various embodiments, the forming the grooves step further comprises machining the implant blank to have at least one of: a semicircular shape, a semi-elliptical shape, a semi-oval shape, or a half-tear drop shape.

[0010] In various embodiments, the forming the grooves step may further comprise machining at least one exposed surface of the superior metallic endplate or inferior metallic endplate to a depth of about 0.25 mm to about 1.0 mm deep by performing a plurality of passes with a machining tool.

[0011] In various embodiments, the forming the grooves step may further comprise machining the exposed surfaces of the superior metallic endplate and inferior metallic endplate to have a plurality of half-tear drop shaped grooves by performing a plurality of passes with a machining tool, each pass of the machining tool being oriented at an angle, with respect to a shaft of the machining tool and a corresponding surface of the implant blank, between about 30 degrees to about 60 degrees. In various embodiments, the forming the grooves step may further comprise machining the exposed surfaces of the superior metallic endplate and the inferior metallic endplate to form a plurality of teeth. In various embodiments, the plurality of teeth step may comprise machining the exposed surfaces of the superior metallic endplate and the inferior metallic endplate to form a saw tooth configuration. In various embodiments, the forming the saw tooth configuration step may comprise machining the exposed surfaces of the superior metallic endplate and theinferior metallic endplate to a distance of about 1.0 mm to about 3.5 mm between center, or peak of the teeth.

[0012] In certain embodiments, the injection molding process may further comprise selecting a thermoplastic polymer from the group consisting of: poly etheretherketone, polyetherketoneketone, polyetherketone, carbon-polyetheretherketone composites, polyetheretherketone-BaSO4 polymeric rubbers, polyethylene terephthalate, and combinations thereof. In various embodiments, the bonding process of step (a) may further comprise selecting porous metallic sheets and non-porous metallics sheets from the group consisting of: titanium, titanium alloys, Grade 5 titanium, superelastic titanium alloys, cobalt-chrome alloys, superelastic metallic alloys, ceramics, stainless steel alloys, or combinations thereof. In other embodiments, after the anodization step, the method may further comprise depositing nanoscale structures on the exposed surfaces of the superior metallic endplate and the inferior metallic endplate. In various embodiments, the depositing step may comprise depositing nanorods, nanotubes, or nanowires formed from an oxide of the metallic endplate.

[0013] Another aspect of the present disclosure relates to an interbody implant formed from the method disclosed above. An interbody implant may, for example, include a superior metallic endplate and an inferior metallic endplate comprising a first plurality of porous metallic sheets, a non-porous metallic sheet, and a second plurality of porous metallic sheets, respectively, wherein the superior metallic endplate and the inferior metallic endplate each may include grooves on exposed surfaces thereof that are configured to increase friction between the interbody implant and adjacent vertebral endplates and a polymeric body disposed between the superior metallic endplate and the inferior metallic endplate, wherein the polymeric body is at least partially impregnated within corresponding pore spaces on the first plurality of porous metallic sheets of the superior metallic endplate and corresponding pore spaces on the first plurality of porous metallic sheets of the inferior metallic endplate.

[0014] In certain embodiments, the interbody implant may include a superior metallic endplate and an inferior metallic endplates each comprising a first plurality of porous metallic sheets bonded to a first side of the non-porous metallic sheet and a second plurality of porous metallic sheets bonded to a second side of the non-porous metallic sheet opposite the first side of the non-porous metallic sheets creating a solid barrierbetween the first plurality of porous metallic sheets and the second plurality of metallic sheets. In various embodiments, the polyermic body of the interbody implant may comprise a thermoplastic polymer selected from the group consisting of: polyetheretherketone, polyetherketoneketone, polyetherketone, carbonpolyetheretherketone composites, polyetheretherketone-BaSO4 polymeric rubbers, polyethylene terephthalate, and combinations thereof. In various embodiments, the superior metallic endplate and the inferior metallic endplate each may comprise a metal selected from the group consisting of: titanium, titanium alloys, Grade 5 titanium, superelastic titanium alloys, cobalt-chrome alloys, superelastic metallic alloys, ceramics, stainless steel alloys, and combinations thereof.

[0015] In various embodiments, the grooves of the superior metallic endplate and the inferior metallic endplate may comprise a semicircular shape, a semi-elliptical shape, a half-tear drop shape, or a combination thereof. In some embodiments, the superior metallic endplate and the inferior metallic endplate may each comprise a plurality of teeth formed between the grooves on the exposed surfaces of the superior metallic endplate and inferior metallic endplate. In certain embodiments, the distance between the center of the teeth may be between about 1.0 mm to about 3.5 mm apart. In various embodiments, the depth of each groove may be between about 0.25 mm to about 1.0 mm deep.

[0016] The details of one or more aspects of the disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the techniques described in this disclosure will be apparent from the description and drawings, and from the claims.BRIEF DESCRIPTION OF DRAWINGS

[0017] FIG. 1 is a flow chart of describing method of manufacturing an interbody implant of the present invention.

[0018] FIG. 2 is a front perspective view of an interbody implant.

[0019] FIG. 3 is a rear perspective view of an interbody implant.

[0020] FIG. 4 is a top-down view of an interbody implant.

[0021] FIG. 5A is an exploded parts view of a metallic endplate of an interbody implant.

[0022] FIG. 5B is an exposed parts view of a polymeric interbody of an interbody implant.

[0023] FIG. 6 is a side view of an interbody implant.

[0024] FIG. 7 is a zoomed-in perspective of a nose portion of an interbody implant.

[0025] FIG. 8 is a zoomed-in perspective of a metallic plate.

[0026] FIG. 9 is a zoomed-in perspective of portions of a metallic endplate.

[0027] FIG. 10 is a front perspective view of a second example of an interbody implant.

[0028] FIG. 11 is a rear perspective view of a second example of an interbody implant.

[0029] FIG. 12 is a top-down perspective view of a second example of an interbody implant.

[0030] FIG. 13 is a side perspective view of a second example of an interbody implant.

[0031] FIG. 14 is a zoomed-in perspective of portions of a second example of metallic endplate.

[0032] FIG. 15 is a perspective view of a third example of an interbody implant.

[0033] FIG. 16 is a top-down view of a third an interbody implant.

[0034] FIG. 17 is a rear perspective view of a third example of an interbody implant.

[0035] FIG. 18 is a side perspective view of a third example of an interbody implant.

[0036] FIG. 19 depicts a reference diagram of the human spine.

[0037] FIG. 20 depicts a reference diagram of various anatomical planes of the human body.DETAILED DESCRIPTION

[0038] Embodiments of the present disclosure relate generally, for example, to spinal stabilization systems, and more particularly, for example, to implants used as spinal stabilization systems. Embodiments of the devices and methods are described below with reference to the Figures.

[0039] The following discussion omits or only briefly describes certain components, features and functionality related to medical implants, installation tools, and associated surgical techniques, which are apparent to those of ordinary skill in the art. It is noted that various embodiments are described in detail with reference to the drawings, in which likereference numerals represent like parts and assemblies throughout the several views, where possible. Reference to various embodiments does not limit the scope of the claims appended hereto because the embodiments are examples of the inventive concepts described herein. Additionally, any example(s) set forth in this specification are intended to be non-limiting and set forth some of the many possible embodiments applicable to the appended claims. Further, particular features described herein can be used in combination with other described features in each of the various possible combinations and permutations unless the context or other statements clearly indicate otherwise.

[0040] Terms such as “same,” “equal,” “planar,” “coplanar,” “parallel,” “perpendicular,” etc. as used herein are intended to encompass a meaning of exactly the same while also including variations that may occur, for example, due to manufacturing processes. The term “substantially” may be used herein to emphasize this meaning, particularly when the described embodiment has the same or nearly the same functionality or characteristic, unless the context or other statements clearly indicate otherwise. Additionally, it shall be understood that the term “about” encompasses a variation of at least + / - 10% from the example values provide herein.

[0041] The following discussion includes a description of, for example, an interbody implant and related methods of manufacturing the interbody implant in accordance with the principles of the present disclosure. Alternate embodiments are also disclosed. Reference is made in detail to the exemplary embodiments of the present disclosure, which are illustrated in the accompanying figures. FIGS. 1-18, there are illustrated components of an interbody implant, such as, for example an interbody implant 100, 200, or 300.

[0042] Various embodiments and components of the exemplary interbody implant of present disclosure may be fabricated from biologically acceptable materials suitable for medical applications, including metals, synthetic polymers, ceramics and bone material and / or their composites. For example, the components, individually or collectively, can be fabricated from materials such as stainless steel alloys, commercially pure titanium, titanium alloys, Grade 5 titanium, superelastic titanium alloys, cobalt-chrome alloys, superelastic metallic alloys (e.g., Nitinol, super elastoplastic metals, such as GUM METAL®), ceramics and composites thereof such as calcium phosphate (e.g., SKELITE™), thermoplastics such as polyaryletherketone (PAEK) includingpoly etheretherketone (PEEK), poly etherketoneketone (PEKK) and poly etherketone (PEK), carbon-PEEK composites, PEEK-BaSCU polymeric rubbers, polyethylene terephthalate (PET), fabric, silicone, polyurethane, silicone-polyurethane copolymers, polymeric rubbers, polyolefin rubbers, hydrogels, semi-rigid and rigid materials, elastomers, rubbers, thermoplastic elastomers, thermoset elastomers, elastomeric composites, rigid polymers including polyphenylene, polyamide, polyimide, polyetherimide, polyethylene, epoxy, bone material including autograft, allograft, xenograft or transgenic cortical and / or corticocancellous bone, and tissue growth or differentiation factors, partially resorbable materials, such as, for example, composites of metals and calcium-based ceramics, composites of PEEK and calcium based ceramics, composites of PEEK with resorbable polymers, totally resorbable materials, such as, for example, calcium based ceramics such as calcium phosphate, tri-calcium phosphate (TCP), hydroxyapatite (HA)-TCP, calcium sulfate, or other resorbable polymers such as polyketide, polyglycolide, polytyrosine carbonate, polycaprolactone, polylactic acid or polylactide and their combinations.

[0043] Various embodiments and components may be coated with a ceramic, titanium, and / or other biocompatible material to provide microscale or nanoscale surface texturing or structures, for example. Similarly, components may undergo a subtractive manufacturing process providing for millimeter or centimeter surface texturing or structures configured to facilitate osseointegration and cellular attachment and osteoblast maturation. Example surface texturing or structuring of additive and subtractive manufacturing processes may comprise features such as grooves on at least one exposed surface of the superior or inferior endplates having a depth of about 0.25 mm to about 1.0 mm, and nanoscale structures such as nanorods, nanotubes, or nanowires having 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, the structural features may be overlapping with one another, for example. Additionally, such surface texturing may be applied to any surface, e.g., both external exposed facing surfaces of components and internal non exposed surfaces of components.

[0044] Suitable subtractive techniques to produce surface structures / features may include, for example, machining (e.g., machining tools, such as saws, lathes, milling, machines, drill presses, electrical discharge machining (EDM)) is used to physicallyremove material to achieve the desired geometry and dimensions of the groove structures. The desired structure may be formed by performing a plurality of passes with the machining tool at various angles to achieve the desired geometry configured for optimal insertion and provide friction force to improve migration resistance in an installed state. Suitable additive techniques to produce the desired surface structures may include, for example, 3D printing, injection molding, or deposition, based on the desired structural geometry and parameters. Further discussion regarding exemplary surface texturing is described in, for example, U.S. Pat. No. 11,096,796, titled “Interbody spinal implant having a roughened surface topography on one or more internal surfaces,” and filed on March, 4, 2013 - the entire disclosure of which is incorporated herein by reference in its entirety. Accordingly, it shall be understood that any of the described texturing processes of U.S. Pat. No. 11,096,796, may be applied to any component of the various embodiments disclosed herein, e.g., the exposed surfaces and internal surfaces of endplates.

[0045] After forming of the grooves or structure, an additional surface treatment step may be applied to produce or deposit nanostructures on the outermost surface of the interbody. The nanostructures may be also formed from mechanical and chemical subtractive techniques, for example, machining or chemical etching, or additive techniques such as, for example, surface deposition of nanostructured oxides nanoscale structures such as nanorods, nanotubes, or nanowires of the metallic surface. This surface treatment provides a protection layer that provides corrosion-resistance, prevents wear and tear, and improves the biological response during bone healing. In various embodiments, anodization of the outermost metallic surface may be applied prior to the surface treatment of the metallic endplates.

[0046] Referring generally to FIG. 1, a flow chart for manufacturing the various interbody implant embodiments of FIGS. 2-18 is disclosed. Referring generally to FIGS. 2-5, various views of an interbody implant 100 are disclosed. FIGS. 2 and 3 illustrate front and rear perspective views of implant 100 and FIG. 4 illustrates a top-down view of implant 100.

[0047] In FIG. 1, a first step 101 may include forming a metallic endplate by a diffusion bonding process. This step may include the formation of a superior metallic endplate and an inferior metallic endplate, respectively, by bonding of a plurality ofporous metallic sheets to a non-porous metallic sheet. An example bonding process may be a diffusion bonding process. The exposed surfaces of the endplates may be porous for adhering to a polymer or other material thereto in a subsequent step. A second step 102 may include forming the polymeric body or core of the interbody implant. In various embodiments, this step may include injection molding a thermoplastic polymer between the lower surface of the superior metallic endplate 10S and the upper surface of the inferior metallic endplate 101. The thermoplastic polymer may flow into the pore spaces of the superior metallic endplate and inferior metallic endplate and couple these components together. After forming the polymeric body between the metallic endplates, the subsequent step 103 may include forming micro- scale grooves on the surface of the superior metallic endplate 10S and the inferior metallic endplate 101 by mechanical machining. The machining process may be carried out by, for example, a subtractive manufacturing process including machining tools such as saws, lathes, burrs, milling, and drill presses. After forming the grooves, step 104 may include applying surface treatment to form nanoscale structures on the metallic endplate surface. An example surface treatment process may be an electrochemical anodization to form metallic oxide nanotubes. The surface treatment step 104 may facilitate a biological response such as, for example, bone ingrowth or fusion. Various steps and methods may be used and / or modified in view of the detailed description of the apparatus embodiments shown in FIGS. 2-18. The steps described in FIG. 1 should be understood in the context of the description of the manufactured implant, which is described below in detail.

[0048] FIGS. 5A and 5B illustrate exploded parts views of implant 100 comprising a superior metallic endplate 10S and inferior metallic endplates 101 (FIG. 5A), and the polymeric body 20 (FIG. 5B). In the example embodiment, implant 100 may be formed of a first component comprising metallic endplates 10 and a second component comprising polymeric body 20 (may also be referred to as a polymeric core) disposed between the metallic endplates 10. In various embodiments, the metallic endplates 10 may include a superior metallic endplate 10S and an inferior metallic endplate 101. In various embodiments, polymeric body 20 may be produced by an injection molding a thermoplastic polymer between a lower surface of the superior metallic endplate 10S and an upper surface of the inferior metallic endplate 101. In some embodiments, the thermoplastic polymer used to produce the polymeric core may comprisepolyetheretherketone (PAEK), polyetherketoneketone (PEEK), polyetherketone (PEKK), carbon-polyetheretherketone composites, polyetheretherketone-BaSCU polymeric rubbers, polyethylene terephthalate (PET), or combinations thereof.

[0049] With reference to FIG. 4, implant 100 may extend in a proximal to distal direction along longitudinal axis A-A from a proximal end 100P to a distal end 100D. Additionally, implant 100 may extend in a widthwise direction along lateral axis B-B between a first lateral end 100L and a second lateral end 100L. In various embodiments, the cross-section geometry of interbody implant 100 may have various configurations, such as, for example, cylindrical, round, oval, oblong, triangular, polygonal having planar or arcuate side portions, irregular, uniform, non-uniform, consistent, variable, horseshoe shape, U- shape or kidney bean shape.

[0050] As seen best in FIGS. 2 and 3, metallic endplate 10 may include a first opening 15 and polymeric body 20 may include a second opening 22 aligning with and adjoining first opening 15. In this embodiment, openings 15, 22 may be configured to receive an agent, which may include bone graft (not shown) and / or other materials, for employment in a fixation or fusion treatment. Further, As seen in FIGS. 2 and 3, and more explained in FIG. 9, metallic endplates 10 may comprise a plurality of pores 16 along the surface of the metallic endplate 10. In various embodiments, metallic endplates 10 may comprise a plurality of grooves 14.

[0051] As seen best in FIG. 2, interbody implant 100 may include various contours and / or features to facilitate posterior insertion of implant 100 inside of a patient. In the example embodiment, a proximal end 100P of interbody implant 100 may include gripping indentations 21 and a threaded aperture 25. In use, a surgeon may use a surgical tool to grasp onto implant 100 at gripping indentations 21 and / or by threadingly engaging a surgical tool (not illustrated) to the threaded aperture 25, for example.

[0052] Referring to FIGS. 5A and 5B, superior metallic endplate 10S and inferior metallic endplates 101 (FIG. 5A) may be standalone structures interconnected by the polymeric body 20 (FIG. 5B) to form an implant blank. In various embodiments, superior endplate 10S and inferior metallic endplate 101 may extend in a proximal to distal direction having a proximal end 10P and a distal end 10D. The lower surface of superior metallic endplate 10S and upper surface of the inferior metallic endplate 101 may be in contact with the upper and lower surfaces of polymeric body 20 and may be stabilized byan injection molding process to prevent disassembly. With reference to FIG. 5B, polymeric body 20 may extend in a proximal to distal direction having a proximal end 20P and a distal end 20D. As explained further below and in FIG. 9, in various embodiments, the lower surface of superior metallic endplate 10S and the upper surface of inferior metallic endplate 101 that come in contact with polymeric body 20 may be configured to include pores 16 for the injected thermoplastic polymers to occupy, harden, and grasp.

[0053] FIG. 6 is a side perspective view of interbody implant 100. In various embodiments, the interbody implant 100 may extend in a longitudinal direction from a proximal end 100P to a distal end 100D. The interbody implant 100 may include angled nose portion 26 at the distal end 20D configured for posteriorly inserting the interbody implant. In various embodiments, the interbody implant may include plurality of grooves 14 on the outer surfaces of the metallic endplates 10S and 101. Referring to FIG. 7, a zoomed-in perspective of nose portion 26 at distal end 20D is shown. In some embodiments, the nose portion may be configured at an angle p with respect to the longitudinal axis of the interbody implant to provide desired inclination for insertion of the implant by straight impaction. In various embodiments, angle p 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, nose portion 26 may be formed by machining the implant blank by machine tools, such as saws, lathes, burrs, milling machines, and drill presses. In some embodiments, the gripping indention 21 and threaded aperture 25 (shown in FIG. 3) at the proximal end 100P of the implant may be formed by machining the implant blank by machine tools, such as saws, lathes, burrs, milling machines, and drill presses.

[0054] Referring now to FIG. 8, a zoomed-in perspective of a metallic endplate 10 is shown. In various embodiments, metallic endplate may include a series of grooves 14 configured to increase friction between the interbody implant 100 and boney anatomy of a patient and to prevent migration of the implant 100 post-installation. In various embodiments, grooves 14 may be formed by a subtractive mechanical processing step comprising at least one of: electrical discharge machining, milling, lathing, burring, sawing, or sanding. In various embodiments, subtractive processing may be performed to achieve the groove depth D to a depth 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 toabout 0.65 mm. In some embodiments, grooves 14 may be machined to have at least one of: a semicircular shape, a semi-elliptical shape, a semi-oval shape, or a half-tear drop shape. In various embodiments, asymmetrical shapes such as the half-tear drop shape as exemplified in FIG. 8, may be formed by performing a plurality of passes with a machining tool, with each pass being orientated at an angle with respect to the shaft of the machining tool and the corresponding surface of the implant blank. In various embodiments, the grooves may be configured at an angle a on one side of the groove and providing a sharp edge on the opposite side of the groove to prevent the interbody implant from backing out. In various embodiments, the angle a may be about 30 degrees to about 60 degrees. In various embodiments, the distance (L) between a groove 14 and adjacent groove 14 may be about 0.25 mm to about 1.5 mm, about 0.50 mm to about 1.25 mm, or about 0.75 mm to about 1.0 mm.

[0055] In various embodiments, grooves 14 may be machined to form a plurality of teeth that may be referred to as a saw tooth configuration. In various embodiments, metallic endplates 10 may be machined such that the distance between the center, (or peak) of the teeth in a saw tooth 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.

[0056] Referring to FIG. 9, a zoomed-in perspective of portions of a metallic endplate is shown. In various embodiments, superior metallic endplate 10S or inferior metallic endplate 101 may comprise a first plurality of porous metallic sheets 11 that come in contact with the upper and lower surfaces of the polymeric body 20, a second plurality of porous metallic sheets 13 comprising the exposed surface of the interbody implant 100, and a non-porous metallic sheet 12 disposed between the first plurality of porous metallic sheets 11 and the second plurality of porous metallic sheets 13. In various embodiments, metallic sheets 11, 12, and 13 are bonded by a diffusion bonding process. In various embodiments, non-porous metallic sheet 12 is disposed between the porous metallic sheets 11 and 13 to prevent the thermoplastic polymer from flowing from first plurality of porous metallic sheets 11 into second plurality of porous metallic sheets 13 during the injection molding process.

[0057] In various embodiments, the first plurality of porous metallic sheets 11 may comprise 1 to 2 individual porous metallic sheets. It shall be appreciated that any numberof porous metallic sheets in plurality of porous metallic sheets 11 is contemplated depending on the desired thickness. In some embodiments, second plurality of porous metallic sheets 13 may comprise 2 to 3 individual porous metallic sheets. It shall be appreciated that any number of porous metallic sheets in plurality of porous metallic sheets 13 is contemplated depending on the desired thickness. In some embodiments, the individual porous metallic sheets and non-porous metallic sheet 12 each may be about 0.20 mm to about 0.30 mm thick. In certain embodiments, the plurality of porous metallic sheets 11 and 13 are configured such that a majority of pores 16 of adjacently stacked porous metallic sheets are offset from each other. This offset configuration may facilitate the bonding process. In various embodiments, the plurality of porous metallic sheets 11 and 13 each may comprise about 45% to about 70%, about 50% to about 65%, or about 55% to about 60% volume % void, i.e., how much of an overall volume is empty space, or air.

[0058] In some embodiments, the second plurality of porous metallic sheets 13 may be machined to form grooves. In various embodiments, the machining process may include machining the second plurality of porous metallic sheets 13 to a depth that does not contact the corresponding non-porous metallic sheet 12. In various embodiments, the machining process may include machining second plurality of porous metallic sheets 13 to a depth that passes through at least a portion of the corresponding non-porous metallic sheet 12. In various embodiments, the non-porous metallic sheet 12 may provide a barrier to the first plurality of porous metallic sheets 11 in contact with the polymeric body 20 such that machining process does not extend to the first plurality of porous metallic sheets 11. In this manner, the polymeric body 20 does not migrate from the pores 16 of the first plurality of porous metallic sheets 11 to the pores 16 on the second plurality of porous metallic sheets 13. In various embodiments, during the machining process, interbody implant may be cooled to a temperature suitable to prevent polymeric body 20 from deforming and detaching from the metallic endplates 10.

[0059] After machining the grooves, a surface treatment may be applied on the surface of metallic endplate 10 to further protect the surface from corrosion, wear and tear, and to improve the biological response during bone healing. For example, the surface treatment may facilitate bone growth. In various embodiments, the surface treatment may comprise anodizing the surface of the metallic endplates to produce metallic oxides of the metallicendplate. For example, a metallic endplate formed from titanium may form nanoscale titanium oxide nanostructures such as, nanorods, nanotubes, and nanowires. In various embodiments, the nanoscale structures may be about 35 nm to about 85 nm, about 50 nm to about 70 nm, or about 55 nm to about 60 nm in diameter. Additionally, the nanoscale structures may have an average length of at least about 10 nm.

[0060] FIGS. 10 and 11 are front and rear perspective views, respectively, of a second example of an interbody implant 200 that may be manufactured by the methods described in this disclosure. Interbody implant 200 may have the same, similar and / or substantially the same features and functionality as explained above with respect to interbody implant 100. For example, interbody implant 200 may include superior metallic endplates 30, and a polymeric body 40 that is disposed between the superior metallic endplate 30S and the inferior metallic endplate 301. As seen best in FIGS. 10 and 11 metallic endplate 30 may include a first opening 35 and polymeric body 40 may include a second opening 42 aligning with and adjoining first opening 35. In this embodiment, openings 35, 42 may be configured to receive an agent, which may include bone graft (not shown) and / or other materials, for employment in a fixation or fusion treatment. Further, As seen in FIGS. 10 and 11, metallic endplates 30 may comprise a plurality of pores 36 along the surface of endplate 30. In various embodiments, metallic endplates 30 may comprise a plurality of grooves 34. In this embodiment, proximal end 200P of interbody implant 200 may include gripping indentations 41 and a threaded aperture 45 for threadingly engaging a surgical tool, for example. With reference to FIG. 12, implant 200 may extend in a proximal to distal direction along longitudinal axis A-A from a proximal end 200P to a distal end 200D. Additionally, implant 200 may extend in a widthwise direction along axis C-C between a first lateral end 200L and a second lateral end 200L.

[0061] In this embodiment, interbody implant 200 may include a dull nose portion 46 at distal end 200D. As seen in the top-down and side perspective views in FIGS. 12 and 13, the dolphin nose portion 46 may be designed in such way that it does not require an impact insertion technique as may be utilized for implants that do not include such a dolphin nose portion 46 or similar structure. In this configuration, interbody implant 200 may be configured to be posteriorly inserted into the surgical area along the A-A - B-B plane then rotated about A-A axis to allow grooves 34 to contact the bone and be oriented to suppress migration. Additionally, FIG. 14 shows a zoomed-in perspective of portions ofa second example of metallic endplate 30. In the example configuration of FIG. 14, grooves 34 are machined to a semi-circular shape having a depth that corresponds to the radius R of the semi-circle grooves.

[0062] FIGS. 15 and 16 are a perspective view and a top-down view, respectively, of a third example interbody implant 300 manufactured by the methods described in this disclosure. Interbody implant 300 may have the same, similar and / or substantially the same features and functionality as explained above with respect to interbody implant 100 and interbody implant 200. As seen best in FIG. 15 interbody implant 300 may include a first opening 55 and polymeric body 60 may include a second opening 62 aligning with and adjoining first opening 55. In this embodiment, openings 55, 62 may be configured to receive an agent, which may include bone graft (not shown) and / or other materials, for employment in a fixation or fusion treatment. With reference to FIG. 16, implant 300 may extend in a proximal to distal direction along longitudinal axis A-A from a proximal end 300P to a distal end 300D. Additionally, implant 300 may extend in a widthwise direction along lateral axis B-B between a first lateral end 300L and a second lateral end 300L. In this embodiment, interbody implant 300 may include two threaded apertures 65 and 66 to use with an inserter tool (not shown) for laterally inserting the interbody implant 300 to the surgical area. As seen in FIG. 17, the interbody implant may have an uneven, tapered geometry having a first height Hl at one lateral side 300L, and a second height H2 at the opposite lateral side 300L. FIG. 18 is a side perspective from the shorter lateral side showing grooves 54 and pores 56 on both superior metallic endplate 50S and inferior metallic endplate 501.

[0063] FIG. 19 is a reference drawing showing the human spine of which various disclosed implant embodiments may be installed in. The human spine, as depicted in FIG. 19, consists of a stack of 33 curved vertebrae that are structurally divided into five regions, namely, cervical region (C1-C7), thoracic region (T1-T12), lumbar region (L1-L5) and, the fused sacrum and coccyx regions. Towards the bottom of the spine, the vertebrae are larger because the spine supports heavier loads of the body in this area. The cervical vertebrae, forming the neck area, are relatively small to promote flexibility of the head and because they support smaller loads relative to the thoracic and lumbar regions. Just below the cervical vertebrae are the thoracic vertebrae, which form the upper back. The thoracic vertebrae are larger than the cervical vertebrae and increase in size from top towardsbottom. Below the thoracic region lies the lumbar vertebrae, which are even larger and support the weight of the entire upper body. Relative motion in the spine may also vary along the length of the spinal column, as the cervical vertebra have a greater range of motion than the lower lumbar vertebra. FIG. 20 is a reference drawing showing various planes and reference directions of which the various disclosed implant embodiments may move in or act in with reference to a patient.

[0064] It should be understood that various aspects disclosed herein may be combined in different combinations than the combinations specifically presented in the description and accompanying drawings. For example, features, functionality, and components from one embodiment may be combined with another embodiment and vice versa unless the context clearly indicates otherwise. Similarly, features, functionality, and components may be omitted unless the context clearly indicates otherwise. It should also be understood that, depending on the example, certain acts or events of any of the processes or methods described herein may be performed in a different sequence, may be added, merged, or left out altogether (e.g., all described acts or events may not be necessary to carry out the techniques).

[0065] Unless otherwise specifically defined herein, all terms are to be given their broadest possible interpretation including meanings implied from the specification as well as meanings understood by those skilled in the art and / or as defined in dictionaries, treatises, etc. It must also be noted that, as used in the specification and the appended claims, the singular forms "a," "an" and "the" include plural referents unless otherwise specified, and that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0066] Without excluding further possible embodiments, certain example embodiments are summarized in the following example clauses:

[0067] Clause 1: A method of manufacturing an interbody implant with metallic endplates and a polymeric body, comprising the steps of: (a) forming a superior metallic endplate and an inferior metallic endplate, respectively, by applying a bonding process to bond a first plurality of porous metallic sheets to a first side of a non-porous metallic sheet and to bond a second plurality of porous metallic sheets to a second side of the non-porousmetallic sheet opposite the first side the non-porous metallic sheet creating a solid barrier between the first plurality of porous metallic sheets and the second plurality of porous metallic sheets; (b) forming a polymeric body by injection molding a thermoplastic polymer between a lower surface of the superior metallic endplate and an upper surface of the inferior metallic endplate, the injection molding of the thermoplastic polymer impregnating corresponding pore spaces on the first plurality of porous metallic sheets of the superior metallic endplate and corresponding pore spaces on the first plurality of porous metallic sheets of the inferior metallic endplate thereby producing an implant blank; and (c) forming grooves on the implant blank by applying a machining process to exposed surfaces of the superior metallic endplate and the inferior metallic endplates.

[0068] Clause 2: The method of clause 1, after the machining process in step (c), further comprising (d) applying an anodization step to the exposed surfaces of the superior metallic endplate and the inferior metallic endplate.

[0069] Clause 3: The method of clause 1 or clause 2, wherein the machining in step (c) is conducted by a subtractive mechanical processing step comprising at least one of: milling, lathing, burring, sawing, or sanding.

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

[0071] Clause 5: The method of any of the preceding clauses, wherein bonding a porous metallic sheet and a non-porous metallic sheet that are each about 0.20 mm to about 0.30 mm thick.

[0072] Clause 6: The method of any of the preceding clauses, wherein the bonding process in step (a) comprises stacking a plurality of porous metallic sheets such that a majority of respective pores of adjacently stacked porous metallic sheets are offset from each other, wherein the plurality of porous metallic sheet comprising about 45% to about 70% volume % void.

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

[0074] Clause 8: The method of any of the preceding clauses, further comprising cooling, during the machining process, the implant blank to a temperature suitable to prevent the polymeric body from deforming.

[0075] Clause 9: The method of any of the preceding clauses, wherein the forming the grooves further comprises machining the exposed surfaces of the superior metallic endplate and inferior metallic endplate to a depth that does not contact the corresponding non-porous metallic sheet.

[0076] Clause 10: The method of clause 9, wherein the forming the grooves step further comprises machining the exposed surfaces of the superior metallic endplate and inferior metallic endplate to a depth that passes through at least a portion of the corresponding non-porous metallic sheet.

[0077] Clause 11: The method of any of the preceding clauses, wherein the forming the grooves step further comprises machining the implant blank to have at least one of: a semicircular shape, a semi-elliptical shape, a semi-oval shape, or a half-tear drop shape.

[0078] Clause 12: The method of clause 11, wherein the forming the grooves step further comprises machining at least one exposed surface of the superior metallic endplate or inferior metallic endplate to a depth of about 0.25 mm to about 1.0 mm deep by performing a plurality of passes with a machining tool.

[0079] Clause 13: The method of clause 11, wherein the forming the grooves step further comprises machining the exposed surfaces of the superior metallic endplate and inferior metallic endplate to have a plurality of half-tear drop shaped grooves by performing a plurality of passes with a machining tool, each pass of the machining tool being oriented at an angle, with respect to a shaft of the machining tool and a corresponding surface of the implant blank, between about 30 degrees to about 60 degrees.

[0080] Clause 14: The method of any of the preceding clauses, wherein the forming the grooves step further comprises machining the exposed surfaces of the superior metallic endplate and the inferior metallic endplate to form a plurality of teeth.

[0081] Clause 15: The method of clause 14, wherein the forming the plurality of teeth step comprises machining the exposed surfaces of the superior metallic endplate and the inferior metallic endplate to form a saw tooth configuration.

[0082] Clause 16: The method of clause 15, wherein the forming the saw tooth configuration step comprises machining the exposed surfaces of the superior metallicendplate and the inferior metallic endplate to a distance of about 1.0 mm to about 3.5 mm between center of the teeth.

[0083] Clause 17: The method of any of the preceding clauses, wherein the injection molding process further comprises selecting a thermoplastic polymer from the group consisting of: poly etheretherketone, poly etherketoneketone, poly etherketone, carbonpolyetheretherketone composites, polyetheretherketone-BaSCU polymeric rubbers, polyethylene terephthalate, and combinations thereof.

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

[0085] Clause 19: The method of clause 2, after the anodization step, further comprising depositing nanoscale structures on the exposed surfaces of the superior metallic endplate and the inferior metallic endplate.

[0086] Clause 20: The method of clause 19, wherein the depositing step comprises depositing nanorods, nanotubes, or nanowires formed from an oxide of the metallic endplate.

[0087] Clause 21: An interbody implant formed by the method of manufacture according to any of the preceding clauses.

[0088] Clause 22: An interbody implant, comprising; a superior metallic endplate and an inferior metallic endplate comprising a first plurality of porous metallic sheets, a non- porous metallic sheet, and a second plurality of porous metallic sheets, respectively, wherein the superior metallic endplate and the inferior metallic endplate each include grooves on exposed surfaces thereof that are configured to increase friction between the interbody implant and adjacent vertebral endplates; and a polymeric body disposed between the superior metallic endplate and the inferior metallic endplate, wherein the polymeric body is at least partially impregnated within corresponding pore spaces on the first plurality of porous metallic sheets of the superior metallic endplate and corresponding pore spaces on the first plurality of porous metallic sheets of the inferior metallic endplate.

[0089] Clause 23: The interbody implant of clause 22, wherein the superior metallic endplate and the inferior metallic endplates each comprises the first plurality of porousmetallic sheets bonded to a first side of the non-porous metallic sheet and the second plurality of porous metallic sheets bonded to a second side of the non-porous metallic sheet opposite the first side of the non-porous metallic sheets creating a solid barrier between the first plurality of porous metallic sheets and the second plurality of metallic sheets.

[0090] Clause 24: The interbody implant of clause 22 or clause 23, wherein the polymeric body comprises a thermoplastic polymer selected from the group consisting of: polyetheretherketone, polyetherketoneketone, polyetherketone, carbonpolyetheretherketone composites, polyetheretherketone-BaSO4 polymeric rubbers, polyethylene terephthalate, and combinations thereof.

[0091] Clause 25: The interbody implant of any of clauses 22-24, wherein the superior metallic endplate and the inferior metallic endplate each comprises a metal selected from the group consisting of: titanium, titanium alloys, Grade 5 titanium, superelastic titanium alloys, cobalt-chrome alloys, superelastic metallic alloys, ceramics, stainless steel alloys, and combinations thereof.

[0092] Clause 26: The interbody implant of any of clauses 22-25, wherein the grooves comprise a semicircular shape, a semi-elliptical shape, a half-tear drop shape, or a combination thereof.

[0093] Clause 27: The interbody implant of any of clauses 22-26, wherein the superior metallic endplate and the inferior metallic endplate each comprises a plurality of teeth formed between the grooves on the exposed surfaces of the superior metallic endplate and inferior metallic endplate.

[0094] Clause 28: The interbody implant of clause 27, wherein a distance between center of the teeth is about 1.0 mm to about 3.5 mm apart.

[0095] Clause 29: The interbody implant of any of clauses 22-28, wherein a depth of each groove of the grooves is about 0.25 mm to about 1.0 mm deep.

Claims

WHAT IS CLAIMED IS:

1. A method of manufacturing an interbody implant (100) with metallic endplates (10) and a polymeric body (20), comprising the steps of:(a) forming a superior metallic endplate (10S) and an inferior metallic endplate (101), respectively, by applying a bonding process to bond a first plurality of porous metallic sheets (11) to a first side of a non-porous metallic sheet (12) and to bond a second plurality of porous metallic sheets (13) to a second side of the non- porous metallic sheet opposite the first side the non-porous metallic sheet creating a solid barrier between the first plurality of porous metallic sheets and the second plurality of porous metallic sheets;(b) forming a polymeric body by injection molding a thermoplastic polymer between a lower surface of the superior metallic endplate and an upper surface of the inferior metallic endplate, the injection molding of the thermoplastic polymer impregnating corresponding pore spaces (16) on the first plurality of porous metallic sheets of the superior metallic endplate and corresponding pore spaces on the first plurality of porous metallic sheets of the inferior metallic endplate thereby producing an implant blank; and(c) forming grooves (14) on the implant blank by applying a machining process to exposed surfaces of the superior metallic endplate and the inferior metallic endplates.

2. The method of claim 1, further comprising applying, after the machining process in step (c), further comprising (d) applying an anodization step to the exposed surfaces of the superior metallic endplate and the inferior metallic endplate.

3. The method of claim 1 or claim 2, wherein the machining in step (c) is conducted by a subtractive mechanical processing step comprising at least one of: milling, burring lathing, sawing, or sanding.

4. The method of any of the preceding claims, wherein bonding a porous metallic sheet and a non-porous metallic sheet that are each about 0.20 mm to about 0.30 mm thick.

5. The method of any of the preceding claims, wherein the bonding process in step (a) is conducted by diffusion bonding.

6. The method of any of the preceding claims, wherein the forming the grooves further comprises machining the exposed surfaces of the superior metallic endplate and inferior metallic endplate to a depth that does not contact the corresponding non- porous metallic sheet.

7. The method of any of the preceding claims, wherein the forming the grooves step further comprises machining the implant blank to have at least one of: a semicircular shape, a semi-elliptical shape, a semi-oval shape, or a half-tear drop shape.

8. The method of claim 7, wherein the forming the grooves step further comprises machining at least one exposed surface of the superior metallic endplate or inferior metallic endplate to a depth of about 0.25 mm to about 1.0 mm deep by performing a plurality of passes with a machining tool.

9. The method of any of the preceding claims, wherein the forming the grooves step further comprises machining the exposed surfaces of the superior metallic endplate and the inferior metallic endplate to form a plurality of teeth.

10. The method of claim 2, after the anodization step, further comprising depositing nanoscale structures on the exposed surfaces of the superior metallic endplate and the inferior metallic endplate.

11. An interbody implant, comprising;a superior metallic endplate and an inferior metallic endplate comprising a first plurality of porous metallic sheets, a non-porous metallic sheet, and a second plurality of porous metallic sheets, respectively, wherein the superior metallic endplate and the inferior metallic endplate each include grooves on exposed surfaces thereof that are configured to increase friction between the interbody implant and adjacent vertebral endplates; and a polymeric body disposed between the superior metallic endplate and the inferior metallic endplate, wherein the polymeric body is at least partially impregnated within corresponding pore spaces on the first plurality of porous metallic sheets of the superior metallic endplate and corresponding pore spaces on the first plurality of porous metallic sheets of the inferior metallic endplate.

12. The interbody implant of claim 11, wherein the superior metallic endplate and the inferior metallic endplates each comprises the first plurality of porous metallic sheets bonded to a first side of the non-porous metallic sheet and the second plurality of porous metallic sheets bonded to a second side of the non-porous metallic sheet opposite the first side of the non-porous metallic sheets creating a solid barrier between the first plurality of porous metallic sheets and the second plurality of metallic sheets.

13. The interbody implant of claim 11 or claim 12, wherein the grooves comprise a semicircular shape, a semi-elliptical shape, a half-tear drop shape, or a combination thereof.

14. The interbody implant of any of claims 11-13, wherein the superior metallic endplate and the inferior metallic endplate each comprises a plurality of teeth formed between the grooves on the exposed surfaces of the superior metallic endplate and inferior metallic endplate, wherein a distance between center of the teeth is about 1.0 mm to about 3.5 mm apart.

15. The interbody implant of any of claims 11-14, wherein a depth of each groove of the grooves is about 0.25 mm to about 1.0 mm deep.

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