Patent Publication Number: US-11020239-B2

Title: Expandable spinal implant system and method of using same

Description:
CROSS-REFERENCE TO RELATED U.S. PATENT APPLICATION 
     This Application claims benefit to U.S. Provisional Patent Application Ser. No. 62/633,952, entitled “EXPANDABLE SPINAL IMPLANT SYSTEM AND METHOD OF USING SAME”, filed Feb. 22, 2018, which is incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The present disclosure generally relates to medical devices for the treatment of musculoskeletal disorders, and more particularly to a surgical system that includes an expandable spinal implant, systems for implanting an expandable spinal implant, and a method for treating a spine. 
     BACKGROUND 
     Spinal disorders such as degenerative disc disease, disc herniation, osteoporosis, spondylolisthesis, stenosis, scoliosis and other curvature abnormalities, kyphosis, tumor, and fracture may result from factors including trauma, disease and degenerative conditions caused by injury and aging. Spinal disorders typically result in symptoms including pain, nerve damage, and partial or complete loss of mobility. 
     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 fusion, fixation, correction, discectomy, laminectomy and implantable prosthetics. 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 devices may be introduced to a space between adjacent vertebral bodies (the interbody space) to properly space the vertebral bodies and provide a receptacle for bone growth promoting materials. 
     More recently, interbody devices have been introduced that provide additional capability beyond static spacing of the vertebral bodies. For example, some devices have expansion capability such that the implant may be introduced to the interbody space in a collapsed state and then expanded to produce additional spacing and, in some cases, introduce or restore curvature to the spine by expanding selectively on only one end or portion of the implant. However, many existing expandable interbody designs have limited ranges of expansion. 
     An additional problem exists related to subsidence of spinal surfaces due to existing interbody devices having inadequately-sized load-bearing surfaces. In the case of expandable devices, the loads on the load-bearing surfaces, including loads generated during expansion of the implant, are often significant. An expandable implant with relatively large surface areas is needed to bear the loads, including the loads generated during implant expansion, in an attempt to avoid a need for follow-on surgery due to subsidence of spinal surfaces. 
     A further problem is instability of existing expandable interbody devices as they are expanded. Often, the load-bearing surfaces move relative to one another, as well as relative to an inserter, as the interbody device is expanded such that there is a risk of undesired shifts in the positioning of the interbody device within the interverterbral space. 
     The present invention seeks to address these and other shortcomings in the existing art. 
     SUMMARY 
     In one aspect, the present disclosure provides an expandable spinal implant deployable between a contracted position and an expanded position in a disc space between two vertebral bodies, the expandable spinal implant comprising a first endplate, the first endplate including an outer surface and an inner surface, a first endplate first end, a first endplate second end, a first endplate first lateral surface extending between the first endplate first end and the first endplate second end, an opposing first endplate second lateral surface extending between the first endplate first end and the first endplate second end; a second endplate, the second endplate including an outer surface and an inner surface, a second endplate first end, a second endplate second end, a second endplate first lateral surface extending between the second endplate first end and the second endplate second end, and an opposing second endplate second lateral surface extending between the second endplate first end and the second endplate second end, wherein the second endplate first end is pivotably engaged with the first endplate first end; an expansion mechanism disposed between the first endplate and the second endplate, the expansion mechanism including a wedge disposed between the first endplate and second endplate, the wedge including an upper surface, a lower surface, a wedge first end, a wedge second end, a wedge first lateral surface extending between the wedge first end and the wedge second end, and an opposing wedge second lateral surface extending between the wedge first end and the wedge second end, wherein the wedge comprises a wedge aperture between the wedge second end and wedge first end; a rod assembly, the rod assembly having a first end and a second end defining a longitudinal axis, wherein at least a portion of the rod assembly is disposed within the wedge aperture and operably engaged with the wedge to translate the wedge along the longitudinal axis of the rod; and wherein the wedge is operably engaged with at least one of the first endplate or second endplate and configured to expand the implant when the wedge is translated along the rod assembly in a first direction, and contract the implant when the wedge is translated along the rod assembly in a second direction. 
     In some embodiments, the rod assembly comprises a threaded outer surface, and the wedge aperture comprises a threaded inner surface operably engaged with the threaded outer surface of the rod. 
     In some embodiments, the translation of the wedge along the longitudinal axis of the rod in a first direction is towards the first and second endplate first ends. In some embodiments, translation of the wedge along the longitudinal axis of the rod in the first direction is towards the first and second endplate second ends. 
     In some embodiments, at least one of the first endplate or the second endplate further comprises at least one protrusion from its inner surface configured to engage a surface of the wedge. In some embodiments, at least one of the wedge first lateral surface and the wedge second lateral surface comprises a lateral post extending therefrom. 
     In some embodiments, at least one of the first endplate or second endplate further comprises at least one protrusion from its inner surface, wherein the at least one protrusion defines at least one lateral channel configured to receive the lateral post such that when the wedge is translated in the first direction, the lateral post of the wedge is moved in the first direction in the lateral channel to expand the implant and that when the wedge is translated in the second direction, the lateral post of the wedge is moved in the second direction in the lateral channel to contract the implant. 
     In some embodiments, the expandable spinal implant further comprises at least one vertebral endplate engagement component operably engaged to at least one of the first endplate or the second endplate and configured to engage with the wedge such that it protrudes from the outer surface of the first or second endplate when the wedge is translated in the first direction. In some embodiments, the vertebral endplate engagement component is configured to engage with the wedge such that it retracts from the outer surface of the first or second endplate when the wedge is translated in the second direction. 
     In some embodiments, the expandable spinal implant is capable of expanding up to 30 degrees, 35 degrees, 40 degrees, 45 degrees, 50 degrees, or 60 degrees or anywhere in between these amounts from 0 to 60 degrees. 
     In some embodiments, the expansion mechanism is secured to the second endplate. In some embodiments, the first end of the second endplate comprises a first aperture and the second end of the second endplate comprises a second aperture, and wherein the first end of the rod assembly is disposed within the first aperture and the second end of the rod assembly is disposed within the second aperture. In some embodiments, the rod assembly comprises a rod having a first and second end and a securing pin comprising a first and second end, the first end of the rod engaged with the second end of the securing pin, wherein the securing pin is disposed through the first aperture and the second end of the rod is disposed within the second aperture. 
     In some embodiments, the first endplate first end further comprises at least one protrusion comprising a lumen therethrough extending laterally along the first endplate first end; the second endplate first end further comprises at least one protrusion comprising a lumen therethrough extending laterally along the second endplate first end; and the lumen through the at least one protrusion on the first endplate first end is co-axially aligned with the lumen through the at least one protrusion on the second endplate first end, and a rod is disposed through the lumens to pivotably engage first endplate first end with the second endplate first end. 
     In some embodiments, at least one of the first or second endplate comprises an aperture disposed therethrough from the outer surface to the inner surface, the aperture configured to receive an external screw for securing the first or second endplate to a vertebral body. In some embodiments, at least one of the first or second endplate comprises a tab extending from the first or second end, wherein the tab comprises an aperture therethrough configured to receive an external screw for securing first or second endplate to a vertebral body. 
     In some embodiments, at least one of the outer surfaces of the first or second endplates comprise anti-migration and/or anti-expulsion features. In some embodiments, at least one of the first or second endplates comprise apertures between the inner and outer surfaces thereof to allow bone growth material to be loaded into the implant. In some embodiments, at least one of the first or second endplates is porous. 
     In another aspect, the present disclosure provides an expandable spinal implant system comprising an insertion instrument comprising a drive cannula and a drive shaft removably and rotatably disposed within the drive cannula, and further comprising an attachment cannula and an attachment shaft removably and rotatably disposed within the attachment cannula; and an expandable spinal implant deployable between a contracted position and an expanded position in a disc space between two vertebral bodies, the expandable spinal implant comprising a first endplate, the first endplate including an outer surface and an inner surface, a first endplate first end, a first endplate second end, a first endplate first lateral surface extending between the first endplate first end and the first endplate second end, an opposing first endplate second lateral surface extending between the first endplate first end and the first endplate second end; a second endplate, the second endplate including an outer surface and an inner surface, a second endplate first end, a second endplate second end, a second endplate first lateral surface extending between the second endplate first end and the second endplate second end, and an opposing second endplate second lateral surface extending between the second endplate first end and the second endplate second end, wherein the second endplate first end is pivotably engaged with the first endplate first end; an expansion mechanism disposed between the first endplate and the second endplate, the expansion mechanism including a wedge disposed between the first endplate and second endplate, the wedge including an upper surface, a lower surface, a wedge first end, a wedge second end, a wedge first lateral surface extending between the wedge first end and the wedge second end, and an opposing wedge second lateral surface extending between the wedge first end and the wedge second end, wherein the wedge comprises a wedge aperture between the wedge second end and wedge first end; a rod assembly, the rod assembly having a first end and a second end defining a longitudinal axis, wherein at least a portion of the rod assembly is disposed within the wedge aperture and operably engaged with the wedge to translate the wedge along the longitudinal axis of the rod; and wherein the wedge is operably engaged with at least one of the first endplate or second endplate and configured to expand the implant when the wedge is translated along the rod assembly in a first direction, and contract the implant when the wedge is translated along the rod assembly in a second direction. 
     In another aspect, the present disclosure provides a method of deploying an expandable spinal implant in a disc space between two vertebral bodies, the method comprising utilizing an expandable spinal implant deployable between a contracted position and an expanded position in a disc space between upper and lower vertebral bodies, the expandable spinal implant comprising a first endplate, the first endplate including an outer surface and an inner surface, a first endplate first end, a first endplate second end, a first endplate first lateral surface extending between the first endplate first end and the first endplate second end, an opposing first endplate second lateral surface extending between the first endplate first end and the first endplate second end; a second endplate, the second endplate including an outer surface and an inner surface, a second endplate first end, a second endplate second end, a second endplate first lateral surface extending between the second endplate first end and the second endplate second end, and an opposing second endplate second lateral surface extending between the second endplate first end and the second endplate second end, wherein the second endplate first end is pivotably engaged with the first endplate first end; an expansion mechanism disposed between the first endplate and the second endplate, the expansion mechanism including a wedge disposed between the first endplate and second endplate, the wedge including an upper surface, a lower surface, a wedge first end, a wedge second end, a wedge first lateral surface extending between the wedge first end and the wedge second end, and an opposing wedge second lateral surface extending between the wedge first end and the wedge second end, wherein the wedge comprises a wedge aperture between the wedge second end and wedge first end; a rod assembly, the rod assembly having a first end and a second end defining a longitudinal axis, wherein at least a portion of the rod assembly is disposed within the wedge aperture and operably engaged with the wedge to translate the wedge along the longitudinal axis of the rod; and wherein the wedge is operably engaged with at least one of the first endplate or second endplate and configured to expand the implant when the wedge is translated along the rod assembly in a first direction, and contract the implant when the wedge is translated along the rod assembly in a second direction; inserting the implant in the collapsed position into the disc space between the upper and lower vertebral bodies; and expanding the first and second endplates. 
     In other aspects of the present disclosure, various other implants, systems and methods are disclosed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure is further informed by the specific description accompanied by the following drawings, in which: 
         FIG. 1  is a perspective view of one embodiment of an expandable spinal implant in a closed configuration in accordance with the principles of the present disclosure; 
         FIG. 2  is a perspective view of one embodiment of an expandable spinal implant in an expanded configuration in accordance with the principles of the present disclosure; 
         FIG. 3  is a side view of one embodiment of an expandable spinal implant in a closed configuration in accordance with the principles of the present disclosure; 
         FIG. 4  is a side view of one embodiment of an expandable spinal implant in an expanded configuration in accordance with the principles of the present disclosure; 
         FIG. 5  is a side view of one embodiment of an expandable spinal implant in an expanded configuration in accordance with the principles of the present disclosure; 
         FIG. 6  is an exploded perspective view of one embodiment of an expandable spinal implant in an expanded configuration in accordance with the principles of the present disclosure; 
         FIG. 7  is an exploded perspective view of one embodiment of an expandable spinal implant in an expanded configuration in accordance with the principles of the present disclosure; 
         FIG. 8  is an exploded side view of one embodiment of an expandable spinal implant in an expanded configuration in accordance with the principles of the present disclosure; 
         FIG. 9  is an exploded end view of one embodiment of an expandable spinal implant in an expanded configuration in accordance with the principles of the present disclosure; 
         FIG. 10  is a perspective view of one embodiment of an expandable spinal implant in a closed configuration in accordance with the principles of the present disclosure; 
         FIG. 11  is a perspective view of the inner surface of one embodiment of an endplate in accordance with the principles of the present disclosure; 
         FIG. 12  is a perspective view of the outer surface of one embodiment of an endplate in accordance with the principles of the present disclosure; 
         FIG. 13  is a top cutaway view of one embodiment of an expandable spinal implant and inserter in accordance with the principles of the present disclosure; 
         FIG. 14  is a perspective view of one embodiment of an expandable spinal implant in a closed configuration in accordance with the principles of the present disclosure; 
         FIG. 15  is a perspective view of one embodiment of an expandable spinal implant in an expanded configuration in accordance with the principles of the present disclosure; 
         FIG. 16  is a side view of one embodiment of an expandable spinal implant in a closed configuration in accordance with the principles of the present disclosure; 
         FIG. 17  is a side view of one embodiment of an expandable spinal implant in an expanded configuration in accordance with the principles of the present disclosure; 
         FIG. 18  is a perspective view of one embodiment of an expandable spinal implant in an expanded configuration in accordance with the principles of the present disclosure; 
         FIG. 19  is a perspective view of one embodiment of an expandable spinal implant in an expanded configuration in accordance with the principles of the present disclosure; 
         FIG. 20A-B  is a (A) perspective view and (B) plane view of the outer surface of one embodiment of an endplate in accordance with the principles of the present disclosure; 
         FIG. 21A-B  is a (A) perspective view and (B) plane view of the outer surface of one embodiment of an endplate in accordance with the principles of the present disclosure; 
         FIG. 22A-B  is a (A) perspective view and (B) plane view of the outer surface of one embodiment of an endplate in accordance with the principles of the present disclosure; 
         FIG. 23A-B  is a (A) perspective view and (B) plane view of the outer surface of one embodiment of an endplate in accordance with the principles of the present disclosure; 
         FIG. 24A-C  depict one embodiment of an expandable spinal implant and inserter in various positions (A, B, C) in accordance with the principles of the present disclosure; 
         FIG. 25  is a top view of one embodiment of an expandable spinal implant as used in a spinal procedure in accordance with the principles of the present disclosure; 
         FIG. 26  is a top view of one embodiment of an expandable spinal implant as used in a spinal procedure in accordance with the principles of the present disclosure; 
         FIG. 27  is a side view of one embodiment of an expandable spinal implant in a closed configuration in accordance with the principles of the present disclosure; 
         FIG. 28  is a side view of one embodiment of an expandable spinal implant in an expanded configuration in accordance with the principles of the present disclosure; 
         FIG. 29  is a cutaway side view of one embodiment of an expandable spinal implant in a closed configuration in accordance with the principles of the present disclosure; 
         FIG. 30  is a perspective view of one embodiment of an expandable spinal implant in a partially expanded configuration in accordance with the principles of the present disclosure; 
         FIG. 31A-B  is a (A) perspective view and (B) plane view of the outer surface of one embodiment of an endplate in accordance with the principles of the present disclosure; 
         FIG. 32A-B  is a (A) perspective view and (B) plane view of the outer surface of one embodiment of an endplate in accordance with the principles of the present disclosure; 
         FIG. 33A-B  is a (A) perspective view and (B) plane view of the outer surface of one embodiment of an endplate in accordance with the principles of the present disclosure; 
         FIG. 34A-B  is a (A) perspective view and (B) plane view of the outer surface of one embodiment of an endplate in accordance with the principles of the present disclosure; 
         FIG. 35  is an end view of one embodiment of an expansion mechanism wedge in accordance with the principles of the present disclosure; 
         FIG. 36  is a top view of one embodiment of an endplate in accordance with the principles of the present disclosure; 
         FIG. 37  is a side view of one embodiment of an expandable spinal implant as used in a spinal procedure in accordance with the principles of the present disclosure; 
         FIG. 38  is a side view of one embodiment of an expandable spinal implant as used in a spinal procedure in accordance with the principles of the present disclosure; 
         FIG. 39  is a side view of one embodiment of an expandable spinal implant as used in a spinal procedure in accordance with the principles of the present disclosure. 
     
    
    
     Common numbering schemes in  FIGS. 1-39  (e.g., 1xx, 2xx and 3xx), indicate similar components of implants  10 ,  20 , and  30 . 
     DETAILED DESCRIPTION 
     The exemplary embodiments of the surgical system and related methods of use disclosed are discussed in terms of medical devices for the treatment of musculoskeletal disorders and more particularly, in terms of an expandable surgical implant system that may include an expandable spinal implant, an insertion instrument, specialized instruments such as, for example, an expandable retractor and a spinal surgical table that rotates and bends the patient in various directions, and/or a method or methods for treating a spine. 
     In some embodiments, the present system includes an expandable spinal implant suitable for insertion from an oblique, postero-lateral procedures and/or transforaminal lumbar interbody fusions (sometimes referred to as TLIF procedures), direct posterior (sometimes referred to as PLIF procedures), direct lateral (sometimes referred to as DLIF procedures), anterior lumbar interbody fusions (sometimes referred to as ALIF procedures), or variations of these procedures, in which the present implant is inserted into an interverterbral space and then expanded in order to impart and/or augment a lordotic and/or kyphotic curve of the spine. 
     In some embodiments, the spinal implant system may also be employed to restore and/or impart sagittal balance to a patient by increasing and/or restoring an appropriate lordotic and/or kyphotic angle between vertebral bodies at a selected level where the spinal implant is implanted and expanded. In the various embodiments described, the spinal implant system may be useful in a variety of complex spinal procedures for treating spinal conditions beyond one-level fusions. Furthermore, the spinal implant system described in the enclosed embodiments may also be used as a fusion device with an expandable height for tailoring the implant to a particular interbody disc space to restore the spacing between adjacent vertebral bodies and facilitate spinal fusion between the adjacent vertebral bodies. 
     In some embodiments, and as mentioned above, the present disclosure may be employed to treat spinal disorders such as, for example, degenerative disc disease, disc herniation, osteoporosis, spondylolisthesis, stenosis, scoliosis and other curvature abnormalities, kyphosis, tumor and fractures. In some embodiments, the present disclosure may be employed with other osteal and bone related applications, including those associated with diagnostics and therapeutics. In some embodiments, the disclosed spinal implant system may be alternatively employed in a surgical treatment with a patient in a prone or supine position, and/or employ various surgical approaches to the spine, including anterior, posterior, posterior mid-line, direct lateral, postero-lateral oblique, and/or antero lateral oblique approaches, and in other body regions. The present disclosure may also be alternatively employed with procedures for treating the lumbar, cervical, thoracic, sacral and pelvic regions of a spinal column. The spinal implant system of the present disclosure may also be used on animals, bone models and other non-living substrates, such as, for example, in training, testing and demonstration. 
     The present disclosure may be understood more readily by reference to the following detailed description of the embodiments taken in connection with the accompanying drawing figures, which form a part of this disclosure. It is to be understood that this application is not limited to the specific devices, methods, conditions or parameters described and/or shown herein, and that the terminology used herein is for the purpose of describing particular embodiments by way of example only and is not intended to be limiting. In some embodiments, as used in the specification and including the appended claims, the singular forms “a,” “an,” and “the” include the plural, and reference to a particular numerical value includes at least that particular value, unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” or “approximately” one particular value and/or to “about” or “approximately” another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another embodiment. It is also understood that all spatial references, such as, for example, horizontal, vertical, top, upper, lower, bottom, left and right, are for illustrative purposes only and can be varied within the scope of the disclosure. For example, the references “upper” and “lower” are relative and used only in the context to the other, and are not necessarily “superior” and “inferior”. Generally, similar spatial references of different aspects or components, e.g., a “first end” of an end plate and a “first end” of a wedge, indicate similar spatial orientation and/or positioning, i.e., that each “first end” is situated on or directed towards the same end of the device. Further, the use of various spatial terminology herein should not be interpreted to limit the various insertion techniques or orientations of the implant relative to the positions in the spine. 
     As used in the specification and including the appended claims, “treating” or “treatment” of a disease or condition refers to performing a procedure that may include administering one or more drugs, biologics, bone grafts (including allograft, autograft, xenograft, for example) or bone-growth promoting materials to a patient (human, normal or otherwise or other mammal), employing implantable devices, and/or employing instruments that treat the disease, such as, for example, micro-discectomy instruments used to remove portions bulging or herniated discs and/or bone spurs, in an effort to alleviate signs or symptoms of the disease or condition. Alleviation can occur prior to signs or symptoms of the disease or condition appearing, as well as after their appearance. Thus, treating or treatment includes preventing or prevention of disease or undesirable condition (e.g., preventing the disease from occurring in a patient, who may be predisposed to the disease but has not yet been diagnosed as having it). In addition, treating or treatment does not require complete alleviation of signs or symptoms, does not require a cure, and specifically includes procedures that have only a marginal effect on the patient. Treatment can include inhibiting the disease, e.g., arresting its development, or relieving the disease, e.g., causing regression of the disease. For example, treatment can include reducing acute or chronic inflammation; alleviating pain and mitigating and inducing re-growth of new ligament, bone and other tissues; as an adjunct in surgery; and/or any repair procedure. Also, as used in the specification and including the appended claims, the term “tissue” includes soft tissue, ligaments, tendons, cartilage and/or bone unless specifically referred to otherwise. The term “bone growth promoting material” as used herein may include, but is not limited to: bone graft (autograft, allograft, xenograft) in a variety of forms and compositions (including but not limited to morselized bone graft); osteoinductive material such as bone morphogenetic proteins (BMP) (including but not limited to INFUSE® available from Medtronic) and alternative small molecule osteoinductive substances; osteoconductive materials such as demineralized bone matrix (DBM) in a variety of forms and compositions (putty, chips, bagged (including but not limited to the GRAFTON® family of products available from Medtronic)); collagen sponge; bone putty; ceramic-based void fillers; ceramic powders; and/or other substances suitable for inducing, conducting or facilitating bone growth and/or bony fusion of existing bony structures. Such bone growth promoting materials may be provided in a variety of solids, putties, liquids, colloids, solutions, or other preparations suitable for being packed or placed into or around the various implant  10 ,  20 ,  30  embodiments described herein. 
     The following discussion includes a description of a surgical system including one or more spinal implants, related components and methods of employing the surgical system in accordance with the principles of the present disclosure. Various alternate embodiments are disclosed and individual components of each embodiment may be used with other embodiments. Reference is made in detail to the exemplary embodiments of the present disclosure, which are illustrated in the accompanying figures. Turning to  FIGS. 1-36 , there are illustrated components of a surgical system, such as, for example, an expandable spinal implant  10 ,  20 , and  30 . 
     The components of the expandable spinal implant systems described herein can 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 of expandable spinal implant system, individually or collectively, can be fabricated from materials such as stainless steel alloys, commercially pure titanium, titanium alloys, Grade 5 titanium, super-elastic titanium alloys, cobalt-chrome alloys, stainless steel alloys, superelastic metallic alloys (e.g., Nitinol, super elasto-plastic metals, such as GUM METAL®), ceramics and composites thereof such as calcium phosphate (e.g., SKELITE™), thermoplastics such as polyaryletherketone (PAEK) including polyetheretherketone (PEEK), polyetherketoneketone (PEKK) and polyetherketone (PEK), carbon-PEEK composites, PEEK-BaSO 4  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 polyaetide, polyglycolide, polytyrosine carbonate, polycaprolactone and their combinations. 
     Various components of spinal implant system may be formed or constructed of material composites, including but not limited to the above-described materials, to achieve various desired characteristics such as strength, rigidity, elasticity, compliance, biomechanical performance, durability and radiolucency or imaging preference. The components of expandable spinal implant system, individually or collectively, may also be fabricated from a heterogeneous material such as a combination of two or more of the above-described materials. The components of the expandable spinal implant systems may be monolithically formed, integrally connected or include fastening elements and/or instruments, as described herein. For example, in some embodiments the expandable spinal implant systems may comprise expandable spinal implants  10 ,  20 ,  30  comprising PEEK and/or titanium structures with radiolucent markers (such as tantalum pins and/or spikes) selectively placed in the implant to provide a medical practitioner with placement and/or sizing information when the expandable spinal implant  10 ,  20 ,  30  is placed in the spine. The components of the expandable spinal implant system may be formed using a variety of subtractive and additive manufacturing techniques, including, but not limited to machining, milling, extruding, molding, 3D-printing, sintering, coating, vapor deposition, and laser/beam melting. Furthermore, various components of the expandable spinal implant system may be coated or treated with a variety of additives or coatings to improve biocompatibility, bone growth promotion or other features. For example, the endplates  110 ,  120 ,  210 ,  220 ,  310 ,  320  may be selectively coated with bone growth promoting or bone ongrowth promoting surface treatments that may include, but are not limited to: titanium coatings (solid, porous or textured), hydroxyapatite coatings, or titanium plates (solid, porous or textured). 
     The expandable spinal implant system may be employed, for example, with a minimally invasive procedure, including percutaneous techniques, mini-open and open surgical techniques to deliver and introduce instrumentation and/or one or more spinal implants at a surgical site within a body of a patient, for example, a section of a spine. In some embodiments, the expandable spinal implant system may be employed with surgical procedures, as described herein, and/or, for example, corpectomy, discectomy, fusion and/or fixation treatments that employ spinal implants to restore the mechanical support function of vertebrae. In some embodiments, the expandable spinal implant system may be employed with surgical approaches, including but not limited to: anterior lumbar interbody fusions (ALIF), posterior lumbar interbody fusion (PLIF), oblique lumbar interbody fusion, transforaminal lumbar interbody fusion (TLIF), various types of anterior fusion procedures, and any fusion procedure in any portion of the spinal column (sacral, lumbar, thoracic, and cervical, for example). 
     Generally in  FIGS. 1-36 , three exemplary embodiments of an expandable spinal implant  10 ,  20 , and  30  are shown (implant  10  is highlighted in exemplary  FIGS. 1-13 , implant  20  is highlighted in exemplary  FIGS. 14-26 , and implant  30  is highlighted in exemplary  FIGS. 27-36 ). Expandable spinal implants  10 ,  20 , and  30  may comprise first and second endplates operably engaged via a hinge mechanism that lordotically or angularly expands the endplates relative to one another via a wedge mechanism driven perpendicularly to the axis of the hinge joint. In some embodiments, the wedge drive direction may be oriented at an oblique angle between 0 and 90 degrees to the hinge axis. In some embodiments, the first and second endplates may lordotically expand when the wedge mechanism is driven towards the hinge. In other embodiments, the first and second endplates may lordotically expand when the wedge mechanism is driven away from the hinge. 
     As shown in  FIGS. 1-13 , an expandable spinal implant  10  is configured to be inserted in an intervertebral disc space between adjacent vertebral bodies. The implant  10  includes a first end  12  and a second end  14  defining a mid-longitudinal axis L 1 -L 1  therebetween. In some embodiments, the expandable spinal implant  10  comprises a first endplate  110  and second endplate  120 . First endplate  110  includes a first end  112 , a second end  114 , two opposing side surfaces  115  extending from the first end  112  of the first endplate to a portion of the second end  114  of the first endplate, and with the first endplate being therebetween, an inner surface  116 , and an outer surface  118 . Second endplate  120  includes a first end  122 , a second end  124 , two opposing side surfaces  125  extending from the first end  122  of the second endplate to a portion of the second end  124  of the second endplate, and with the second endplate being therebetween, an inner surface  126 , and an outer surface  128 . In one embodiment, endplates  110 ,  120  include projections  111 ,  121  configured to engage a surface of an endplate of an adjacent vertebral body (not shown). Projections  111 ,  121  may comprise various anti-migration, anti-expulsion, and/or osseointegration features including, but not limited to: ridges, teeth, pores, and coatings (including but not limited to porous titanium coatings such as those provided on Capstone PTC™ implants available from Medtronic). The endplates  110 ,  120  may further comprise at least one opening  113 ,  123  defined therein, configured to allow bone growth materials to be packed, placed, or loaded into implant  10 . 
     Referring generally to  FIGS. 1-12 , endplates  110 ,  120  may be operably engaged via a hinge mechanism located near or on first ends  112  and  122 . For example, as shown in  FIG. 7 , first end  112  of first endplate  110  may comprise first and second hinge protrusions  117  extending along at least a portion of the length of first end  112  perpendicular to mid-longitudinal axis L 1 -L 1 . In some embodiments, first and second hinge protrusions are cylindrical and extend from lateral side surfaces  115  towards the mid-longitudinal axis L 1 -L 1 , and further comprise lumen  117   b  extending therethrough. First end  122  of second endplate  120  may also comprise a hinge protrusion  127 . In some embodiments, hinge protrusion  127  is cylindrical and extends laterally along first end  122 , and further comprises a lumen  127   b  extending therethrough. The lumen of first and second hinge protrusions  117  and lumen of hinge protrusion  127  may be co-axially aligned along a hinge axis H 1 -H 1 . A pin  130  may be disposed within the lumen of hinge protrusions  117 ,  127  to pivotably engage first endplate  110  to second endplate  120 . In this way, first endplate  110  may hinge and/or rotate away from second endplate  120  such that the distance between second ends  114  and  124  is increased along radial arc R. While a simple pin and lumen hinge is shown in some of the pictured embodiments, it should be understood that other types of hinge and/or connection mechanisms may also be used to operably engage the endplates  110 ,  120  of the implant. For example, in some embodiments, a “living hinge” may be utilized wherein the endplates  110 ,  120  are at least partially integrally formed at the hinge point but with cut-outs or flex points that allow the endplates  110 ,  120  to rotate about the hinge connection. Endplates  110 ,  120  may be operably engaged in a number of different ways including but not limited to: integral connections, separable connections, mechanically fixed connections using fastener or adhesives, releasable connections (including, but not limited to keyways and partially open hinges), and other connection types. In some embodiments, endplates  110 ,  120  may be integrally formed using additive manufacturing techniques such as 3D printing, sintering laser/beam melting, casting, extruding, or machined in an integral form using subtractive manufacturing techniques from one or more stock materials. 
     As described herein, the implant  10  may include an expansion mechanism for expanding endplates  110 ,  120  to increase the lordotic angle R of implant  10 . In some embodiments, the expansion mechanism of implant  10  includes a rod assembly  140  having a longitudinal axis E 3 -E 3  comprising a rod  142 , a securing pin  143  and wedge  150  mounted within the implant between first endplate  110  and second endplate  120 . Wedge  150  may comprise a first end  152 , a second end  154 , an upper surface  158 , a lower surface  156 , and opposing lateral surfaces  155  extending between the first and second ends. Wedge  150  may further comprise an aperture  151  between the first and second ends. Rod assembly  140  may comprise rod  142  disposed within aperture  151 . In some embodiments, rod  142  comprises a threaded outer surface  141  configured to be engaged with a complimentary inner threaded surface of aperture  151  of wedge  150  such that the wedge  150  travels forward and backwards along rod  142  between first and second ends of implant  10  when rod  142  is rotated relative to wedge  150 . In some embodiments, rod  142  and securing pin  143  may be integrally formed, and in such embodiments, it will be understood that integral rod assembly  140  may be interchanged with rod  142  in the discussions below. 
     The expansion mechanism of implant  10  may be operably engaged with first or second endplates  110 ,  120 . In some embodiments, the expansion mechanism of implant  10  is secured to second endplate  120 . Hinge protrusion  127  of second endplate  120  may comprise a first end aperture  127   a  through the walls of hinge protrusion  127  and generally perpendicular to lumen  127   b  therethrough. Second end  124  of second endplate  120  may further comprise an aperture  124   a  therethrough. In some embodiments, apertures  127   a  and  124   a  are generally co-axial. One or both ends of rod assembly  140  may be secured within one or both of aperture  124   a  of second end  124  and first aperture  127   a  of hinge protrusion  127  along first end  122  to operably engage the expansion mechanism of implant  10  with second endplate  120 . In the embodiment shown, second end of rod  142  is secured within aperture  124   a , and a cylindrical securing pin  143  disposed through aperture  127   a  coaxially engages an end of rod  142  to further secure the expansion mechanism within implant  10 . Pin  130  disposed within the lumen of hinge protrusions  117 ,  127  may include a cut out portion  131  to allow rod  142  and/or cylindrical securing pin  143  to be disposed through aperture  127   a . In some embodiments, rod assembly  140  is disposed such that longitudinal axis E 1 -E 1  is substantially parallel to mid-longitudinal axis L 1 -L 1  of implant  10  (i.e., perpendicular to hinge axis H 1 -H 1 ). In some embodiments, apertures  124   a  and  127   a  may be aligned such that rod assembly  140  is disposed such that longitudinal axis E 1 -E 1  is at an oblique angle to the mid-longitudinal axis L 1 -L 1  of implant  10  (e.g., between zero and 90 degrees). 
     Rod  142  may be rotatable within apertures  124   a ,  127   a  relative to implant  10 . Inner surface  116  of first endplate  110  may comprise guidewalls  116   a  extending away from the inner surface  116  of first endplate  110 . In some embodiments, guidewalls  116   a  extend perpendicularly away from inner surface  116  of first endplate  110 . In some embodiments, guidewalls  116   a  are oriented substantially parallel to the longitudinal axis L of rod  142  and are disposed a width W apart from one another. In some embodiments, the width W is substantially similar to the width of wedge  150 , with wedge  150  being disposed between guidewalls  116   a . Lateral sides  155  of wedge  150  engage with guidewalls  116   a  such that rotation of wedge  150  relative to implant  10  is prevented. In this way, the interaction between threaded surfaces  141 ,  151  cause wedge  150  to translate along longitudinal axis L of rod  142  when rod  142  is rotated. 
     Wedge  150  may include an upper surface  158  configured to engage with inner surface  116  of first endplate  110  and lordotically expand first endplate  110  away from second endplate  120  when wedge  150  is moved towards first end  12  of implant  10 . For example, upper surface  158  may be ramped or wedge-shaped and suitable for urging a complementary ramped or contoured surface on the inside of first endplate  110  so as to gradually move first endplate  140  away from second endplate  150  as wedge  150  is advanced towards first end  12  along rod  142 . In the embodiment depicted, inner surface  116  of first endplate  110  may further comprise ramps  116   b  to engage upper surface  158  of wedge  150 . In some embodiments, the expansion mechanism may be configured such that lower surface  156  of wedge  150  engages inner surface  126  of second endplate  120  alternatively to, or in addition to, upper surface  158  engaging inner surface  116  of first endplate  110 . In some embodiment, the expansion mechanism may be configured to lordotically expand implant  10  when wedge  150  is moved towards the second end  14  of implant  10 . 
     In some embodiments, the ramp mechanism  158 / 116   b  may cooperate with one or more paired lateral posts  155   a  and channel  116   c  system in order to optimize the opening and/or expansion of implant  10 . Guidewalls  116   a  may comprise lateral channels  116   c . Channels  116   c  may be angled or partially angled to provide a mechanism for assisting in the expansion of implant  10  as wedge  150  is advanced along rod  142  towards the hinge at first end  12  of implant  10 . Wedge  150  may comprise one or more lateral posts  155   a  that engage with channels  116   c  to provide an expansion mechanism configured to urge first endplate  110  away from second endplate  120  when wedge  150  is moved towards first end  12  of implant  10 . Post  155   a  and channel  116   c  mechanism may also aid in making expansion of the implant  10  substantially reversible such that when wedge  150  is moved away from the hinge, lateral posts  155   a  are moved in a second direction in the lateral channels  116   c  to contract first endplate  110  towards second endplate  120  (which may result in implant  10  returning to the closed or unexpanded configuration shown generally in  FIG. 1 ). This reversible feature, combined with the threaded interaction between rod  142  and wedge  150 , renders implant  10  capable of being incrementally expanded or contracted through a substantially infinite adjustable range of motion (bounded only by the length of the channels  116   c ). The length and orientation of channels  116   c  may be adjusted to determine the amount of lordotic expansion. In some embodiments, the design of the expansion mechanism, including the length and orientation of channels  116   c , is configured to allow up to 30 degrees, 35 degrees, 40 degrees, 45 degrees, 50 degrees, or 60 degrees or anywhere in between these amounts from 0 to 60 degrees or more of lordotic expansion as wedge  150  is moved towards the hinge assembly. 
     In some embodiments, various designs may be used to optimize the interaction of wedge  150  with first endplate  110 . Such configurations may include, but are not limited to: sequential ramps or tapered surfaces with varying angles; shallow angle sequential ramps or tapered surfaces leading into higher angle sequential ramps or tapered surfaces, as well as other opening mechanisms (such as the lateral post  155   a  and channel  116   c  system described above that may combine to assist the ramps in expanding implant  10 ). 
     As described above, the expansion mechanism  140 ,  150  of implant  10  is secured to second endplate  120  such that first endplate  110  is urged away from expansion mechanism  140 ,  150  and second endplate  120  when wedge  150  is moved towards first end  12  of implant  10 . In some embodiments, only a first end  145  of rod assembly  140  may be secured to first and/or second endplates  110 ,  120  such that the a second end  146  of rod assembly  140  may move relative to endplates  110 ,  120  as implant  10  is expanded or contracted. In such embodiments, lower surface  156  of wedge  150  may be ramped or wedge-shaped and suitable for urging a complementary ramped or contoured surface on the inside of second endplate  120  so as to gradually move the endplates  110 ,  120  away from each other as the wedge  150  is advanced along the rod  142 . Inner surface  126  of second endplate  120  comprise ramps to engage lower surface  156  of wedge  150 , and/or may comprise guidewalls with channels disposed therein to engage lateral posts extending from wedge  150 , similar to those described above for the interaction of upper surface  158  of wedge  150  with inner surface  116  of first endplate  110 . In some embodiments, various designs may be used to optimize the interaction of wedge  150  with endplates  110 ,  120 . Such configurations may include, but are not limited to: sequential ramps or tapered surfaces with varying angles; shallow angle sequential ramps or tapered surfaces leading into higher angle sequential ramps or tapered surfaces, as well as other opening mechanisms (such as the lateral post  155   a  and channel  116   c  system described above that may combine to assist the ramps in expanding the implant  10 ). 
     As wedge  150  moves towards the hinge, the mechanism loses mechanical advantage because the lever arm between the wedge and hinge joint decreases during expansion. This provides increased force feedback to a medical practitioner using implant  10 , giving the medical practitioner a better feel of anatomical constraints. To supplement the expansion force, implant  10  may be specifically paired or used with other surgical instruments that manipulate the spine. These surgical instruments include, for example, surgical tables, patient positioning frames, and the like, that manipulate the patient and may for example further facilitate and/or adjust access to one or more disc spaces by bending the spine of a patient in various directions and adjusting the orientation of the patient to ease or facilitate access to the spinal surgical location(s). Exemplary surgical tables, patient positioning frames, and the like, and related methods of using them include those described in, e.g., U.S. patent application Ser. Nos. 15/239,239, 15/239,256, 15/337,157, 15/638,802, 15/639,080, 15/672,005, and 15/674,456, all incorporated herein by reference in their entirety. 
     In some embodiments, second end  146  of rod  142  may comprise an interface  144  configured to be operably engaged by a drive shaft (not shown) to rotate rod  142 . Rod interface  144  may comprise a drive receptacle configured to cooperate with an implant-engaging end of the drive shaft. The drive connection between the driver shaft and rod interface  144  may comprise a variety of drive interfaces including but not limited to: multi-lobular drives; hexalobular drives; cross or Phillips head drives; straight or “flat head” drives; square or other polygonal drives; and/or combinations thereof. In other embodiments, first end  145  of rod assembly  140  (via rod  142  or securing pin  143 ) may further comprise an interface configured to be operably engaged by a drive shaft to rotate rod assembly  140 . In this way, implants of the present disclosure may be expanded from both an anterior/oblique and posterior approach. 
     In some embodiments, implant  10  may further comprise vertebral endplate engagement components  170  which are configured to engage the vertebral endplate as the implant  10  is expanding. In some embodiments, vertebral endplate engagement components  170  may be claw- or hook-shaped. It is contemplated that vertebral endplate engagement components  170  may comprise various configurations suitable to engage the vertebral endplate to decrease or prevent potential migration or expulsion of the device from the intervertebral space. As shown in  FIGS. 1 and 3 , when implant  10  is in a collapsed, closed, or unexpanded state, vertebral endplate engagement components  170  may be retracted within the device to allow for easy insertion into the disc space. As shown in  FIGS. 2 and 4 , as implant  10  is expanded, and vertebral endplate engagement components  170  protrude from implant  10  and engage the vertebral endplate to decrease potential migration of the device. In the embodiment depicted in  FIGS. 1-12 , the vertebral endplate engagement components  170  are mounted between guidewalls  116   a  and disposed adjacent upper surface  158  of wedge  150 . Guidewalls  116   a  may each comprise an aperture  171  through which a pin  172  is disposed to mount vertebral endplate engagement components  170  to first endplate  110 . In some embodiments, vertebral endplate engagement components  170  are at least partially rotatable about pin  172 . Vertebral endplate engagement components  170  may be shaped to engage upper surface  158  of wedge  150  as wedge  150  is moved towards first end  12  of implant  10 , causing the teeth  170  to partially rotate about pin  172  and protrude through apertures  119  of first endplate  110  and engage the vertebral endplate. As wedge  150  is moved away from first end  12 , a separate portion of vertebral endplate engagement components  170  may engage upper surface  158  of wedge  150  to retract vertebral endplate engagement components  170  back into the interior of implant  10 . In an alternative embodiment (not shown), vertebral endplate engagement components  170  could be incorporated into a piston. Wedge  150  would engage the piston as implant  10  is expanded. In another embodiment (not shown), vertebral endplate engagement components  170  could be mounted onto a rotating gear. A mating gear on wedge  150  would engage the rotating gear and rotate vertebral endplate engagement components  170  into engagement with the vertebral endplate as the wedge  150  expands implant  10 . In another embodiment (not shown), rod assembly  140  may engage vertebral endplate engagement components  170  directly, via, e.g., threaded outer surface  141 . 
     Although  FIGS. 1-12  depict vertebral endplate engagement components  170  protruding only from first endplate  110 , other embodiments may include vertebral endplate engagement components protruding from second endplate  120 , or from both endplates  110 ,  120 . In some embodiments, implant  10  may be secured through intrinsic screws placed through apertures between inner and outer surfaces of endplates  110  or  120  (as depicted for implant  20  in  FIGS. 18, 19  and discussed below). These screws may be further held in place by external locking mechanisms such as washers, springs, plates or covers that cover or push against at least a portion of the screw top or head. In other embodiments the screws may be held in place by interference fit in the screw hole and/or by features in the screw hole adding friction fit and/or holding force to the screw top or head. In other embodiments, implant  10  may be secured through integrated tabs on endplates  110  or  120  (as depicted for implant  30  in  FIG. 30  and as discussed below) or separable plates that may cover a portion of the intervertebral implant. 
       FIG. 13  shows an implant  10  in use with an insertion instrument  40  to form an expandable spinal implant system according to one embodiment. As shown generally in  FIG. 13 , the system may comprise an insertion instrument  40  comprising an attachment cannula  410  and a driver cannula  420 . Insertion instrument  40  may further comprise an attachment shaft  411  removably and rotatably disposed within attachment cannula  410  and a drive shaft  421  removably and rotatably disposed within driver cannula  420 . The implant engaging end of attachment shaft  411  may comprise a threaded outer surface. Insertion instrument  40  may further comprise a drive engagement component  422  connected to the end of drive shaft  421  via, for example, a u-joint  423 . 
     The system may also further comprise an expandable spinal implant  10  configured to be operably engaged with the insertion instrument  40  using a variety of mechanisms. As described herein, second end  14  of implant  10  may be configured to receive the tool end of insertion instrument  40  to manipulate expandable implant  10 . In one embodiment, second end  124  of second endplate  120  of implant  10  comprises attachment apertures  124   b  disposed laterally adjacent to aperture  124   a . These apertures  124   b  may be spaced and angled relative to mid-longitudinal axis L 1 -L 1  of implant  10  as desired for particular surgical techniques. In some embodiments, apertures  124   b  may be parallel to mid-longitudinal axis L 1 -L 1  of implant  10 . In the depicted embodiment, the axis of apertures  124   b  is angled at approximately 15 degrees relative to mid-longitudinal axis L 1 -L 1 . Apertures  124   b  may comprise an inner threaded surface for engaging the threaded outer surface on the implant engaging end of attachment shaft  411 . In other embodiments, the implant engaging end of attachment shaft  411  may interact with tabs or slots defined by one or both of endplates  110 ,  120 . The attachment shaft  411  may be coaxially placed within the attachment cannula  410  and rotatable therein using the manual end of the attachment cannula (not shown). The manual end of the attachment shaft  411  may comprise a keyed or faceted surface configured for engagement with a quick-release handle (not shown) or a powered driver (not shown) for rotating attachment shaft  411 . 
     In some embodiments, as shown in  FIG. 13 , interface  144  of rod  142  may be configured to be operably engaged by an implant engaging end of drive shaft  421  to translate (by threaded rotation, for example) wedge  150  along rod  142 . Drive shaft  421  may be coaxially placed within drive cannula  420  and rotatable therein using the manual end of drive shaft  421  (not shown). The manual end of drive shaft  421  may comprise a keyed or faceted surface configured for engagement with a quick-release handle (not shown) or a powered driver (not shown) for rotating the drive shaft  421 . Furthermore, rod interface  144  may comprise a drive receptacle configured to cooperate with an implant engaging end of drive shaft  421 . The drive connection between drive shaft  421  and rod interface  144  may comprise a variety of drive interfaces including but not limited to: multi-lobular drives; hexalobular drives; cross or Phillips head drives; straight or “flat head” drives; square or other polygonal drives; and/or combinations thereof. In some embodiments, drive shaft  421  engages rod interface  144  via a drive engagement component  422  connected to the end of drive shaft  421  via, for example, a u-joint  423 . U-joint  423  allows for angulation between the drive shaft  421  and rod assembly  140 . 
       FIGS. 14-26  show various configurations of an implant  20  embodiment according to the present disclosure. Implant  20  is generally similar in construction to implant  10  described above and implant  30  described below, and comprises a first endplate  210  and second endplate  220  operably engaged to one another via a hinge mechanism along an implant first end  22 , and an expansion mechanism comprising a rod assembly  240  and a wedge  250  disposed therebetween. First endplate  210  includes a first end  212 , a second end  214 , opposing side surfaces  215  extending from the first end  212  of the first endplate to a portion of the second end  214  of the first endplate, and with the first endplate being therebetween, an inner surface  216 , and an outer surface  218 . Second endplate  220  includes a first end  222 , a second end  224 , two opposing side surfaces  225  extending from the first end  222  of the second endplate to a portion of the second end  224  of the second endplate, and with the second endplate being therebetween, an inner surface  226 , and an outer surface  228 . In one embodiment, the endplates  210 ,  220  includes projections  211 ,  221  configured to engage a surface of the endplate of the adjacent vertebral body (not shown). Projections  211 ,  221  may comprise various anti-migration, anti-expulsion, and/or osseointegration features including, but not limited to: ridges, teeth, pores, and coatings (including but not limited to porous titanium coatings such as those provided on Capstone PTC™ implants available from Medtronic). Endplates  210 ,  220  may further comprise at least one opening  213 ,  223  defined therein, configured to allow bone growth materials to be packed, placed, or loaded into implant  20 . 
     The endplates  210 ,  220  may be operably engaged via a hinge mechanism located near or on the first ends  212  and  222 . For example, first end  212  of first endplate  210  may comprise first and second hinge protrusions  217  extending along at least a portion of the length of first end  212  perpendicular to mid-longitudinal axis L 2 -L 2 . In some embodiments, first and second hinge protrusions are cylindrical and extend from lateral side surfaces  215  towards the mid-longitudinal axis L 2 -L 2 , and further comprise lumen  217   b  extending therethrough. First end  222  of second endplate  220  may also comprise a hinge protrusion  227 . In some embodiments, hinge protrusion  227  is cylindrical and extends laterally along first end  122 , and further comprises a lumen  227   b  extending therethrough. Lumens  217   b ,  227   b  of hinge protrusions  217 ,  227  may be co-axially aligned along a hinge axis H 2 -H 2 . A pin  230  may be disposed within lumens  217   b ,  227   b  of hinge protrusions  217 ,  227  to pivotably engage first endplate  210  to second endplate  220 . 
     The expansion mechanism  240 ,  250  is designed to expand first endplate  210  and second endplate  220  away from each other as wedge  250  is translated towards second end  24  of implant  20  along rod assembly  240 . Rod assembly  240  may be integrally formed, or may be formed of multiple components for, e.g., ease of manufacturing and/or assembly, like rod assembly  140  above. Rod assembly  240  may be secured to first and/or second endplates  210 ,  220  at a rod first end  245  such that a second rod end  246  may move relative to endplates  210 ,  220  as implant  20  is expanded or contracted (i.e., moved into an opened or closed configuration). In some embodiments, longitudinal axis E 2 -E 2  of expansion mechanism  240 ,  250  may be aligned along mid-longitudinal axis L 2 -L 2  of implant  20 . In other embodiments, longitudinal axis E 2 -E 2  of expansion mechanism  240 ,  250  may be offset from mid-longitudinal axis L 2 -L 2  of implant  20 , as depicted in  FIG. 25 , and/or may be angled obliquely to mid-longitudinal axis L 2 -L 2 , as depicted in  FIG. 26 . As described above for implant  10 , second end  246  of rod assembly  240  may comprise an interface  244  configured to be operably engaged by a drive shaft (not shown) to rotate rod assembly  240 . Rod interface  244  may comprise a drive receptacle configured to cooperate with an implant engaging end of the drive shaft. The drive connection between the drive shaft and rod interface  244  may comprise a variety of drive interfaces including but not limited to: multi-lobular drives; hexalobular drives; cross or Phillips head drives; straight or “flat head” drives; square or other polygonal drives; and/or combinations thereof. In other embodiments, first end  245  of rod assembly  240  may further comprise an interface configured to be operably engaged by a drive shaft to rotate rod assembly  240 . In this way, implants of the present disclosure may be expanded from both an anterior/oblique and posterior approach, as depicted in  FIGS. 25 and 26 . 
     In some embodiments, upper surface  258  and lower surface  256  of wedge  250  may be ramped or wedge-shaped and suitable for urging a complementary ramped or contoured surface on the inside of endplates  210 ,  220  so as to gradually move endplates  210 ,  220  away from each other as wedge  250  is advanced along the rod assembly  240  towards second end  24  of implant  20 . In some embodiments, various designs may be used to optimize the interaction of wedge  250  with endplates  210 ,  220 . Such configurations may include, but are not limited to: sequential ramps or tapered surfaces with varying angles; shallow angle sequential ramps or tapered surfaces leading into higher angle sequential ramps or tapered surfaces, as well as other opening mechanisms (such as a lateral post and channel system). As shown in  FIGS. 21 and 23 , inner surfaces  216 ,  226  of endplates  210 ,  220  may comprise guidewalls  216   a ,  226   a  with lateral channels  216   c ,  226   c  disposed therein to engage lateral posts  255   a  extending from wedge  250 . The mechanism provided by posts  255   a  and channels  216   c ,  226   c  may also aid in making the implant  20  expansion substantially reversible. For example, in the depicted embodiment, when wedge  250  is moved towards second end  24  of implant  20 , posts  255   a  are moved in a first direction in channels  216   c ,  226   c  to expand first endplate  210  and second endplate  220  away from each other (which may result in implant  20  opening to the expanded configuration shown generally in  FIG. 15 ), and when wedge  250  is moved towards first end  22  of implant  20 , posts  255   a  are moved in a second direction in channels  216   c ,  226   c  to contract first endplate  210  and second endplate  220  towards each other (which may result in implant  20  returning to the closed or unexpanded configuration shown generally in  FIG. 14 ). This reversible feature, combined with the threaded interaction between rod assembly  240  and wedge  250  renders implant  20  capable of being incrementally expanded or contracted through a substantially infinite adjustable range of motion (bounded only by the length of channels  216   c ,  226   c ). The design of the expansion mechanism, including the length and orientation of channels  216   c ,  226   c , may be adjusted to determine the amount of lordotic expansion. In some embodiments, implant  20  provides 12 degrees of lordotic correction when in a collapsed/closed state and is capable of up to 32 degrees, 60 degrees, or more of lordotic or hyperlordotic expansion as wedge  250  is moved towards second end  24  of implant  20 . 
     In the depicted embodiment, second endplate  220  may comprise apertures  229  through which one or more screws  270  may be disposed to secure endplate  220  within an intervertebral space. Screws  270  may comprise a threaded outer surface  271  that engages with the inner surface of aperture  229 , which may also be threaded. The engagement between threaded outer surface  271  and inner surface of aperture  229  may be via pitch lock, major/minor lock, or any other thread/pitch interface. 
     In some embodiments, second end  224  of second endplate  220  of implant  20  comprises inserter apertures  224   b  to engage with an insertion instrument  50  to form an expandable spinal implant system. As shown in  FIGS. 24A-C , the number and arrangement of inserter apertures  224   b  allows the insertion instrument  50  to be attached to implant  20  in multiple orientations. This provides user flexibility to place implant  20  within intervertebral space with first endplate  210  superior to second endplate  220  or with first endplate  210  inferior to second endplate  220  such that screws  270  may be placed in either the cephalad or caudad vertebral bodies. In one embodiment, the inserter apertures are offset from mid-longitudinal axis which allows the inserter to be attached at a 15 degree angle allowing the device to be placed from an oblique approach. 
       FIGS. 27-36  show various configurations of an implant  30  embodiment according to the present disclosure. Implant  30  is generally similar in construction to implants  10 ,  20  described above and comprises a first endplate  310  and second endplate  320  operably engaged to one another via a hinge mechanism along the first end  32 , and an expansion mechanism comprising a rod assembly  340  and a wedge  350  disposed between first and second endplates  310 ,  320 . First endplate  310  includes a first end  312 , a second end  314 , opposing side surfaces  315  extending from the first end  312  of the first endplate to a portion of the second end  314  of the first endplate, and with the first endplate being therebetween, an inner surface  316 , and an outer surface  318 . Second endplate  320  includes a first end  322 , a second end  324 , opposing side surfaces  325  extending from the first end  322  of the second endplate to a portion of the second end  324  of the second endplate, and with the second endplate being therebetween, an inner surface  326 , and an outer surface  328 . In one embodiment, the endplates  310 ,  320  includes projections  311 ,  321  configured to engage a surface of the endplate of the adjacent vertebral body (not shown). Projections  311 ,  321  may comprise various anti-migration, anti-expulsion and/or osseointegration features including, but not limited to: ridges, teeth, pores, and coatings (including but not limited to porous titanium coatings such as those provided on Capstone PTC™ implants available from Medtronic). Endplates  310 ,  320  may further comprise at least one opening  313 ,  323  defined therein, configured to allow bone growth materials to be packed, placed, or loaded into implant  30 . 
     The endplates  310 ,  320  may be operably engaged via a hinge mechanism located near or on the first ends  312  and  322 . For example, first end  312  of first endplate  310  may comprise first and second hinge protrusions  317  extending along at least a portion of the length of first end  312  perpendicular to mid-longitudinal axis L 3 -L 3 . In some embodiments, first and second hinge protrusions are cylindrical and extend from lateral side surfaces  315  towards the mid-longitudinal axis L 3 -L 3 , and further comprise lumen  317   b  extending therethrough. First end  322  of second endplate  320  may also comprise a hinge protrusion  327 . In some embodiments, hinge protrusion  327  is cylindrical and extends laterally along first end  322 , and further comprises a lumen  327   b  extending therethrough. Lumens  317   b ,  327   b  of hinge protrusions  317 ,  327  may be co-axially aligned along a hinge axis H 3 -H 3 . A pin  330  may be disposed within lumens  217   b ,  327   b  of hinge protrusions  317 ,  327  to pivotably engage first endplate  310  to second endplate  320 . 
     The expansion mechanism  340 ,  350  is designed to expand first endplate  310  and second endplate  320  away from each other as wedge  350  is translated along rod assembly  340  towards second end  34  of implant  30 . Rod assembly  340  may be integrally formed, or may be formed of multiple components for, e.g., ease of manufacturing and/or assembly, like rod assembly  140  above. Rod assembly  340  may be secured to first and/or second endplates  310 ,  320  at a first end  345  such that the second end  346  may move relative to endplates  310 ,  320  as implant  30  is expanded or contracted. In some embodiments, the longitudinal axis E 3 -E 3  of expansion mechanism  340 ,  350  may be angled obliquely to mid-longitudinal axis L 3 -L 3  at an angle θ, as depicted in  FIG. 36 . The shown device is angled at 15 degrees to optimize access for an oblique approach. As depicted in  FIGS. 32, 34 and 35 , first endplate  310 , second endplate  320 , and wedge  350  are designed with compound surface angles to ensure proper contact between wedge  350  and endplates  310 ,  320  throughout the range of translation 
     As described above for implants  10 ,  20 , the second end  346  of rod assembly  340  may comprise an interface  344  configured to be operably engaged by a drive shaft (not shown) to rotate the rod assembly  340 . Rod interface  344  may comprise a drive receptacle configured to cooperate with an implant engaging end of the drive shaft. The drive connection between the drive shaft and rod interface  344  may comprise a variety of drive interfaces including but not limited to: multi-lobular drives; hexalobular drives; cross or Phillips head drives; straight or “flat head” drives; square or other polygonal drives; and/or combinations thereof. In other embodiments, first end  345  of rod assembly  340  may further comprise an interface configured to be operably engaged by a drive shaft to rotate rod assembly  340 . In this way, implants of the present disclosure may be expanded from both an anterior/oblique and posterior approach, as depicted in  FIG. 36 . 
     In some embodiments, upper surface  358  and lower surface  356  of wedge  350  may be ramped or wedge-shaped and suitable for urging a complementary ramped or contoured surface on the inner surfaces  316 ,  326  of endplates  310 ,  320  so as to gradually move the endplates  310 ,  320  away from each other as wedge  350  is advanced along rod assembly  340 . In some embodiments, various designs may be used to optimize the interaction of the wedge  350  with the endplates  210 ,  220 . For example, as depicted in  FIG. 35 , one lateral side  355  of wedge  350  may be taller than opposing lateral side  355  of wedge  350  such that upper surface  358  and lower surface  356  may be angled. Inner surfaces  316 ,  326  of endplates  310 ,  320  are angled in a complementary manner in order to ensure proper contact between wedge  350  and endplates  310 ,  320  as wedge  350  is translated along rod assembly  340  at an angle oblique to mid-longitudinal axis L 3 -L 3  of implant  30 . Other configurations may include, but are not limited to: sequential ramps or tapered surfaces with varying angles; shallow angle sequential ramps or tapered surfaces leading into higher angle sequential ramps or tapered surfaces, as well as other opening mechanisms (such as a lateral post and channel system). In some embodiments, inner surfaces  316 ,  326  of endplates  310 ,  320  may comprise guidewalls  316   a ,  326   a  with lateral channels  316   c ,  326   c  disposed therein to engage lateral posts  355   a  extending from wedge  350 . The mechanism provided by posts  355   a  and channels  316   c ,  326   c  may also aid in making the implant  30  expansion substantially reversible. For example, in the depicted embodiment, when wedge  350  is moved towards second end  34  of implant  30 , posts  355   a  are moved in a first direction in channels  316   c ,  326   c  to expand first endplate  310  and second endplate  320  away from each other (which may result in implant  30  opening to the expanded configuration shown generally in  FIG. 28 ), and when wedge  350  is moved towards second end  32  of implant  30 , posts  355   a  are moved in a second direction in channels  316   c ,  326   c  to contract the first endplate  310  and second endplate  320  towards each other (which may result in the implant  30  returning to the closed or unexpanded configuration shown generally in  FIG. 27 ). This reversible feature, combined with the threaded interaction between rod assembly  340  and wedge  350  renders implant  30  capable of being incrementally expanded or contracted through a substantially infinite adjustable range of motion (bounded only by the length of the channels  316   c ,  326   c ). The design of the expansion mechanism, including the length and orientation of the channels  316   c ,  326   c , may be adjusted to determine the amount of lordotic expansion. In some embodiments, implant  30  provides 12 degrees of lordotic correction when in a collapsed/closed state and is capable of up to 30 degrees, 60 degrees, or more of lordotic or hyperlordotic expansion as the wedge  350  is moved towards second end  34  of implant  30 . 
     In some embodiments, endplate  320  may comprise one or more tabs  329  comprising an aperture  329   a  through which one or more screws  370  may be disposed to secure endplate  320  within an intervertebral space. Screws  370  may comprise a threaded outer surface  371  that engages with the inner surface of aperture  329   a , which may also be threaded. The engagement between threaded outer surface  371  and the inner surface of aperture  329   a  may be via pitch lock, major/minor lock, or any other thread/pitch interface. 
     In some embodiments, second end  324  of second endplate  320  of implant  30  comprises inserter apertures  324   b  to engage with an insertion instrument (not shown) to form an expandable spinal implant system. The number and arrangement of inserter apertures  324   b  allows the insertion instrument to be attached to implant  30  in multiple orientations. This provides user flexibility to place implant  30  within intervertebral space with first endplate  310  superior to second endplate  320  or with first endplate  310  inferior to second endplate  320  such that the tab  329  may be used to secure second endplate  320  in either the cephalad or caudad vertebral bodies. 
     Spinal implant systems of the present disclosure can be employed with a surgical arthrodesis procedure, such as, for example, an interbody fusion for treatment of an applicable condition or injury of an affected section of a spinal column and adjacent areas within a body, such as, for example, intervertebral disc space between adjacent vertebrae, and with additional surgical procedures and methods. In some embodiments, spinal implant systems can include an intervertebral implant that can be inserted with intervertebral disc space to space apart articular joint surfaces, provide support and maximize stabilization of vertebrae. In some embodiments, spinal implant systems may be employed with one or a plurality of vertebra. 
     A medical practitioner obtains access to a surgical site including vertebrae such as through incision and retraction of tissues. Spinal implant systems of the present disclosure can be used in any existing surgical method or technique including open surgery, mini-open surgery, minimally invasive surgery and percutaneous surgical implantation, whereby vertebrae are accessed through a mini-incision, retractor, tube or sleeve that provides a protected passageway to the area, including, for example, an expandable retractor wherein the sleeve is formed from multiple portions that may be moved apart or together and may be inserted with the portions closed or together and then expanded to allow for insertion of implants of larger size than the closed cross section of the unexpanded retractor portions. In one embodiment, the components of the spinal implant system are delivered through a surgical pathway to the surgical site along a surgical approach into intervertebral disc space between vertebrae. Various surgical approaches and pathways may be used. For example,  FIGS. 37-39  depict various views of a typical anterior lumbar interbody fusion (ALIF) approach using a spinal implant of the present disclosure. Unilateral approaches such as a transforaminal lumbar interbody fusion (TLIF) approach may also be used to place the implant in a substantially oblique position relative to the vertebrae. Multilateral approaches such as those disclosed in U.S. Pat. No. 9,730,684, incorporated herein by reference in its entirety, may also be used with spinal implant systems of the present disclosure. 
     As will be appreciated by one of skill in the art, a preparation instrument (not shown) may be employed to remove disc tissue, fluids, adjacent tissues and/or bone, and scrape and/or remove tissue from endplate surfaces of a first vertebra and/or endplate surface of a second vertebra in preparation for or as part of the procedures utilizing a system of the present disclosure. In some embodiments, the size of implant  10 ,  20 ,  30  is selected after trialing using trialing instruments (not shown) that may approximate the size and configuration of the implants  10 ,  20 ,  30 . In some embodiments, such trials may be fixed in size and/or be fitted with expansion mechanisms similar to the various implant  10 ,  20 ,  30  embodiments described herein. In some embodiments, implant  10  may be visualized by fluoroscopy and oriented before introduction into intervertebral disc space. Furthermore, the insertion instruments  40 ,  50  and implants  10 ,  20 ,  30  may be fitted with fiducial markers to enable image guided surgical navigation to be used prior to and/or during a procedure. 
     Components of a spinal implant system of the present disclosure including implant  10 ,  20 ,  30  can be delivered or implanted as a pre-assembled device or can be assembled in situ. Components of spinal implant system including implant  10 ,  20 ,  30  may be expanded, contracted, completely or partially revised, removed or replaced in situ. In some embodiments, one or all of the components of spinal implant system  10 ,  20 ,  30  can be delivered to the surgical site via mechanical manipulation and/or a free hand technique. 
     In some embodiments, the spinal implant system includes an agent, including but not limited to the bone growth promoting materials described herein, which may be disposed, packed, coated or layered within, on or about the components and/or surfaces of the spinal implant system. In some embodiments the bone growth promoting materials may be pre-packed in the interior of the implant, and/or may be packed during or after implantation of the implant via a tube, cannula, syringe or a combination of these or other access instruments and may be further tamped into the implant before, during or after implantation. In some embodiments, the agent may include bone growth promoting material to enhance fixation of implants  10 ,  20 ,  30  with bony structures. In some embodiments, the agent may include one or a plurality of therapeutic agents and/or pharmacological agents for release, including sustained release, to treat, for example, pain, inflammation and degeneration. 
     In one embodiment, implants  10 ,  20 ,  30  may include fastening elements, which may include locking structure, configured for fixation with vertebrae to secure joint surfaces and provide complementary stabilization and immobilization to a vertebral region. In some embodiments, locking structure may include fastening elements, such as, for example, rods, plates, clips, hooks, adhesives and/or flanges. In some embodiments, the components of spinal implant system  20 ,  30  can be used with screws to enhance fixation. The components of the spinal implant system can be made of radiolucent materials such as polymers. Radiopaque markers may be included for identification under x-ray, fluoroscopy, CT or other imaging techniques. The insertion instruments  40 ,  50  may be radiolucent and may optionally include markers added at the tip and/or along the length of one or both of insertion instruments  40 ,  50  and the tube to permit them to be seen on fluoroscopy/x-ray while advancing into the patient. If the implants  10 ,  20 ,  30  includes radiolucent markers placed near the end this may permit visualization of the proximity of the tip of the tube moving toward the second ends  14 ,  24 ,  34  of implants  10 ,  20 ,  30 . 
     In some embodiments, the use of microsurgical, minimally-invasive and image guided technologies may be employed to access, view and repair spinal deterioration or damage, with the aid of spinal implant system. Upon completion of the procedure, the non-implanted components, surgical instruments and assemblies of spinal implant system may be removed and the incision is closed. In some embodiments, the various instruments disclosed may be provided with fiducial markers or other elements suitable for use with surgical navigation systems (including, but not limited to the STEALTHSTATION® Navigation system available from Medtronic), such that a surgeon may view a projected trajectory or insertion pathway of the implants  10 ,  20 ,  30  relative to a patient&#39;s anatomy in real time and/or in near-real time. 
     It will be understood that the various independent components of the expandable spinal implants  10 ,  20 ,  30 , and insertion instruments  40 ,  50  described herein may be combined in different ways according to various embodiments. 
     It will be understood that various modifications may be made to the embodiments disclosed herein. Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the invention being indicated by the following claims.