Patent Description:
The present disclosure relates to spinal surgery, namely the fusion of adjacent intervertebral bodies or the replacement of a vertebral body.

Back pain can be caused by many different maladies, not the least of which are problems that directly impact the intervertebral discs of the spine. Typical disc issues include, inter alia, degeneration, bulging, herniation, thinning, abnormal movement, spondylosis, spinal stenosis, disc herniation, retrolisthesis, and discogenic back pain. One method of treatment of such disc problems that is widely utilized in the field of spinal surgery is a spinal fusion procedure, whereby an affected disc is removed, and the adjacent vertebral bodies are fused together through the use of interbody spacers, implants, or the like. In some instances, it may also be necessary to remove and replace an entire vertebral body. This is often accomplished through the use of a larger implant that acts to fuse together the vertebral bodies adjacent the removed vertebral body.

In replacing a diseased intervertebral disc(s) and affecting fusion, it may also be necessary to ensure that proper spacing is maintained between the vertebral bodies. It is also the case that an implant must be structured to effectively support and bear the post-surgical loads inherent in movement of the adjacent vertebral bodies of the spine after implantation. At the same time, proper and effective fusion of the vertebral bodies is of concern. Thus, implants exist in which resorbable materials are used to promote fusion, but in many cases these implants are not structurally sound or are susceptible to failure in one way or another. As an example, allograft spacers constitute a resorbable material, but such spacers are often brittle during implantation and can fracture. Other drawbacks to existing resorbable implants also exist. Patent document <CIT> discloses a spinal implant known in the art.

Therefore, there exists a need for an improved spinal implant.

According to the invention, as claimed in claim <NUM>, there is provided an implant sized and adapted for insertion into an intervertebral space between adjacent vertebral bodies. The implant comprises a non-resorbable, structural framework having top and bottom bone-contacting surfaces and a plurality of struts defining geometric openings between the top and bottom surfaces, the struts providing structural support for the framework, wherein the framework includes a plurality of support columns extending between proximal and distal ends of the framework, the plurality of support columns being spaced apart from each other to define vertical openings in the framework. The implant also includes a resorbable material component within and/or around the framework for resorption and formation of new bone to fuse the vertebral bodies together. In certain embodiments of this first aspect, the resorbable material component is a structural component that includes top and bottom bone-contacting surfaces configured to support post-surgical loads experienced after implantation of the implant.

A first aspect of the disclosure includes an implant sized and adapted for insertion into an intervertebral space between adjacent vertebral bodies. The implant comprises a non-resorbable, non-structural framework having top and bottom bone-contacting surfaces formed of a porous material, and a resorbable, structural component positioned between the top and bottom surfaces of the framework to provide structural support for the top and bottom surfaces and the implant. In an embodiment of this second aspect, the top and bottom surfaces of the framework are two millimeters (<NUM>) or less in thickness.

A second aspect of the disclosure includes an implant sized and adapted for insertion into an intervertebral space between adjacent vertebral bodies. The implant comprises a non-structural, non-resorbable framework having a main body and a fluid conduit within the main body, the main body having an injection port in fluid communication with the fluid conduit. The implant also includes a resorbable, structural component having top and bottom bone-contacting surfaces and an opening in at least one of the top and bottom surfaces, the opening being in fluid communication with the fluid conduit. In an embodiment of this third aspect, a fluid conduit projects outward from the main body and is fluidly connected with the fluid conduit in the main body, wherein the outwardly-projecting fluid conduit defines the opening in the at least one of the top and bottom surfaces of the resorbable, structural component.

A third aspect of the disclosure includes an implant sized and adapted for insertion into an intervertebral space between adjacent vertebral bodies. The implant comprises a non-structural, non-resorbable framework having a series of ring members connected together by way of a plurality of struts, and a resorbable, structural component embedded with and/or around the framework for encouraging resorption of the implant and fusion of the vertebral bodies. In an embodiment of this fourth aspect, the ring members are arranged transverse to a longitudinal axis of the framework, and the struts extend along the longitudinal axis and connect the ring members.

A fourth aspect of the disclosure includes a method (not claimed) of reducing subsidence of an implant into bone. The method comprises providing an implant having a non-resorbable structural framework and a resorbable structural component positioned within and/or around the framework. The framework is implanted between first and second adjacent vertebral bodies so that top and bottom surfaces of the framework contact vertebral endplates of the first and second vertebral bodies, and the resorbable component is likewise implanted between the first and second adjacent vertebral bodies so that top and bottom surfaces of the resorbable component contact the vertebral endplates. Once implanted, the top and bottom surfaces of the resorbable component contact the vertebral endplates over a contact surface area sufficient to reduce peak stresses between the framework and the vertebral bodies by an amount effective to eliminate or reduce subsidence of the framework into the vertebral bodies. In the absence of the resorbable component, peak stresses between the framework and the vertebral bodies is above a stress required for the vertebral endplates to fail, for example above <NUM> MPa.

The disclosure includes an implant sized and adapted for insertion into an intervertebral space between adjacent vertebral bodies. The implant comprises a non-resorbable, structural framework having top and bottom bone-contacting surfaces and a plurality of struts defining geometric openings between the top and bottom surfaces, the struts providing structural support for the framework. The implant also includes a resorbable material component within and/or around the framework for resorption and formation of new bone to fuse the vertebral bodies together, wherein the resorbable material has top and bottom bone-contacting surfaces, and the top and bottom surfaces of the resorbable component are arranged to contact the vertebral endplates over a contact surface area sufficient to reduce peak stresses between the framework and the vertebral bodies by an amount effective to reduce or eliminate subsidence of the framework into the vertebral bodies. In an embodiment, the contact surface area is between about <NUM>-<NUM>% of an overall contact surface area of the implant in contact with the vertebral endplates. In another embodiment, in the absence of the resorbable component, peak stresses between the framework and the vertebral bodies is above a stress required for the vertebral endplates to fail.

A more complete appreciation of the subject matter of the present invention and of the various advantages thereof can be realized by reference to the following detailed description in which reference is made to the accompanying drawings in which:.

In describing the preferred embodiments of the invention illustrated and to be described with respect to the drawings, specific terminology will be used for the sake of clarity. However, the invention is not intended to be limited to any specific terms used herein, and it is to be understood that each specific term includes all technical equivalents, which operate in a similar manner to accomplish a similar purpose.

As used herein, the term "structural" means the ability to bear the post-operative service load without the need for a second material. The term "structural" is not restricted to the ability to bear the entire post-operative service load, and may include bearing some (e.g., a therapeutically effective amount) or a majority of the post-operative service load.

The present invention includes a variety of implants that have a non-resorbable framework or skeleton, in certain cases providing structural support and in other cases being non-structural, in combination with a resorbable component or material that is embedded within and/or around the framework. The resorbable component provides structural support in some cases or is non-structural in others. The particular combination of a non-resorbable framework along with a resorbable component or material, as disclosed herein, allows an implant to adequately support adjacent vertebral bodies when implanted during a fusion process while also encouraging positive bone formation and resorption of the implant.

Referring to <FIG>, an implant <NUM> is shown that has a non-resorbable structural framework <NUM> and a resorbable component/material <NUM> embedded within framework <NUM>. Framework <NUM> provides structural support for implant <NUM>, while resorbable material <NUM> encourages or allows for bone formation and fusion for adjacent vertebral bodies contacting implant <NUM>.

Framework <NUM> is shown in detail in <FIG>. Framework <NUM> includes top and bottom bone-contacting surfaces <NUM>, <NUM>, proximal and distal ends <NUM>, <NUM>, and teeth <NUM> formed on top and bottom surfaces <NUM>, <NUM>. In some cases, framework <NUM> is formed through an additive manufacturing process, such as selective laser melting (SLM), selective laser sintering (SLS), 3D printing, or any other additive process. Through the additive process (or by using another manufacturing method), framework <NUM> is created to include a network of struts <NUM> that define a variety of differently-shaped geometric openings <NUM>. Indeed, the body of framework <NUM> may be successively composed layer-by-layer through an additive process, as detailed above, so that struts <NUM> are formed to define the different geometric openings <NUM> of framework <NUM>. In an embodiment, geometric openings <NUM> are present along the sides of framework <NUM>, at proximal and distal ends <NUM>, <NUM>, and along a series of support columns <NUM> of framework <NUM>. Thus, geometric openings <NUM> can provide access to and throughout an interior of framework <NUM> so that bone growth can occur into framework <NUM>, as described in more detail below.

Support columns <NUM> of framework <NUM> each include various struts <NUM> defining geometric openings <NUM>, which act to provide structural support for framework <NUM>. In an embodiment, framework <NUM> is designed to bear a substantial portion (e.g., fifty percent (<NUM>%) or more) of the anticipated post-surgical load for implant <NUM>. Support columns <NUM> also each include portions of top and bottom bone-contacting surfaces <NUM>, <NUM> of framework <NUM>, which have teeth <NUM>. Struts <NUM> support such portions of top and bottom bone-contacting surfaces <NUM>, <NUM>. Support columns <NUM> also define vertical openings <NUM> in framework <NUM>, which may provide areas for resorbable material <NUM> to extend between.

As shown in <FIG>, respectively, framework <NUM> also includes an opening <NUM> (optionally threaded) at its proximal end <NUM> for attachment with an implantation tool (not shown), as well as a bulleted nose <NUM> at its distal end <NUM> to ease implantation of implant <NUM> into a disc space between adjacent vertebral bodies.

In an exemplary embodiment, framework <NUM> is composed of titanium or titanium alloy (porous or solid), tantalum, stainless steel, polyetheretherketone (PEEK), polyetherketoneketone (PEKK), or a material developed by the Applicant, which is referred to as Cortoss®. Combinations of the foregoing materials may also be used. Non-resorbable framework <NUM> can also incorporate osteoconductive materials, resorbable coatings, or resorbable materials within voids or pores of the non-resorbable material to make framework <NUM> an active participant in the fusion process. As an example, framework <NUM> may be constructed of solid and porous portions, as described in Applicant's <CIT>, now <CIT>. As set forth therein, in particular embodiments, the teeth of certain implants can be formed from porous and solid structures. Such teeth could be incorporated into framework <NUM>, or used with any other implant described in more detail below. Additionally, the '<NUM> Application describes other implant structures with porous and solid features, and it is contemplated that such technology may be used with framework <NUM>, or any other framework or implant discussed more fully below.

In an embodiment, top and bottom surfaces <NUM>, <NUM> of framework <NUM> are also tapered towards one another by a degree sufficient to accommodate the natural lordosis that may exist between the adjacent vertebral bodies. Such lordosis exists, for example, between adjacent vertebral bodies in the lumbar spine. Other embodiments, however, may include parallel top and bottom surfaces <NUM>, <NUM>.

Resorbable component/material <NUM> is shown in <FIG>. In an embodiment, resorbable material <NUM> comprises a flowable/curable material that is embedded within and/or around framework <NUM>. Resorbable material <NUM> may also provide structural support for implant <NUM> by defining top and bottom surfaces <NUM>, <NUM> that are arranged to contact adjacent vertebral bodies, in addition to top and bottom surfaces <NUM>, <NUM> of framework <NUM>, and support the vertebral bodies once implant <NUM> is implanted. Indeed, as shown in <FIG>, once material <NUM> is embedded within framework <NUM>, it fills in the space between certain support columns <NUM> and provides top and bottom surfaces <NUM>, <NUM> that are arranged to contact adjacent vertebral bodies. Further, top and bottom surfaces <NUM>, <NUM> include teeth <NUM> for digging into the vertebral bodies. In an embodiment, top and bottom surfaces <NUM>, <NUM> are also tapered towards one another by a degree sufficient to accommodate the natural lordosis that may exist between the adjacent vertebral bodies, but can also be arranged parallel.

Resorbable material/component <NUM> also includes a single vertical opening <NUM> that, when combined with framework <NUM>, provides a vertical opening <NUM> in implant <NUM>. Vertical opening <NUM> may receive, for example, a bone graft material to further enhance the resorptive characteristics of implant <NUM> and promote fusion.

In an exemplary embodiment, resorbable material <NUM> is composed of bioactive glass, bone, polylactides, collagen, magnesium alloy, or a Cross-Linked Microstructure (CLM) bioglass material developed by Bio2 Technologies, Inc. as described, for instance, in Bio2 Technologies' <CIT>. Combinations of the foregoing materials may also be used. Resorbable material <NUM> may include one of the materials above in a collagen or other polymeric carrier to facilitate molding into framework <NUM>. A template manufacturing process may also be used in which calcium phosphate, sol-gel derived bioactive glass, or another ceramic is produced on a porous template which occupies the openings within framework <NUM>, and is then sacrificed by heat treatment so that only the ceramic is left behind. It may also be desirable to fill framework <NUM> with a powder, particulate, or fiber form of resorbable material <NUM> in a mold and then further process by heat, chemical cross-linking or other means to bond or sinter the powder, particulate, or fibers into a solid or porous final state which fills framework <NUM>.

In one case, resorbable material <NUM> may comprise a majority of the overall material volume of implant <NUM>, for example fifty percent (<NUM>%) or more of the overall volume. The resorbable material <NUM> is embedded within struts <NUM>. In addition, although resorbable material <NUM> is described above as providing structural support for implant <NUM>, in an alternate embodiment resorbable material is non-structural depending upon the intended implementation for implant <NUM>. For example, a non-structural resorbable component <NUM> may be useful for applications in which loading is expected to be predictable or additional resistance to subsidence into bone is not required. A structural resorbable component <NUM> may be required to add surface area to reduce local contact pressure where implant <NUM> contacts bone for configurations in which structural framework <NUM> is not adequate to prevent subsidence or other failure of the bone, despite framework <NUM> having the necessary strength to withstand the service load. In either case, the combination of resorbable component <NUM> and framework <NUM> results in a greater fusion mass than what a traditional PEEK or titanium cage would allow, as a majority of implant <NUM>'s volume becomes resorbed and replaced by bone.

In another embodiment, non-resorbable framework <NUM> may be composed of a radiopaque material, and the particular arrangement of framework <NUM> may optimize visualization of the resulting fusion mass within or around the implant. For instance, as shown in the side view of <FIG>, framework <NUM>, in particular struts <NUM> thereof, define geometric openings <NUM> of roughly a diamond shape within an otherwise radiopaque structure, which allows for viewing the resulting fusion mass using standard imaging techniques from a lateral perspective. Moreover, the minimal amount of radiopaque material in this area, as well as the extent of geometric openings <NUM>, provide direct visualization of resorbable component <NUM> under visualization. Generally, with prior art devices, the fusion mass would be occluded from a lateral perspective due to the presence of a radiopaque structure(s) blocking visualization of the mass.

<FIG> shows a Finite Element Analysis of framework <NUM> demonstrating the post-operative loads that framework <NUM> can withstand. The Finite Element Analysis illustrates a load of <NUM>,<NUM> Newtons being applied to framework <NUM>, and the subsequent stresses seen in framework <NUM>. As illustrated, framework <NUM> can withstand the <NUM>,<NUM> Newton load (or greater) without yielding. A load of <NUM>,<NUM> N was selected as it is representative of a typical dynamic service load.

<FIG> shows another Finite Element Analysis of framework <NUM> (without resorbable component <NUM>) in which the scale of the Finite Element Analysis is different than in <FIG>. In <FIG>, the scale is set to one-hundred and sixty megapascals (<NUM> MPa), as that is the typical failure point for bone. Thus, the Finite Element Analysis of <FIG> illustrates the stresses created on framework <NUM> upon application of <NUM>,<NUM> N load, within a scale of one-hundred and sixty megapascals (<NUM> MPa), to thereby illustrate where bone failure might occur anywhere along framework <NUM>. As shown, certain areas of framework <NUM>, illustrated in red, approach or exceed stresses of <NUM> MPa when a <NUM>,<NUM> N load is applied. Thus, at these areas, without resorbable component <NUM> and the support it provides for implant <NUM>, there would likely be failure of vertebral bone and subsidence of framework <NUM> into the bone. In other words, these areas of high local stress on framework <NUM> (without resorbable component <NUM>) would ordinarily result in framework <NUM> subsiding into the vertebral bodies.

As seen in <FIG>, however, which is a Finite Element Analysis of implant <NUM> (i.e., framework <NUM> with resorbable component <NUM>), resorbable component <NUM> acts to distribute loads across the extent of implant <NUM> and thereby reduce the risk of subsidence. As shown, no areas on the top of implant <NUM> approach or exceed <NUM> MPa (the failure point for bone). Instead, maximum stresses across implant <NUM> appear to be on the order of about <NUM>-<NUM> MPa, and in an embodiment are <NUM> MPa. For the Finite Element Analyses of <FIG>, framework <NUM> was constructed as a scaffold of Ti6Al4V, having a Young's Modulus of about <NUM>,<NUM> MPa and Poison's Ratio of <NUM>, while resorbable component was composed of a biologic material having a Young's Modulus of <NUM> GPa and Poison's Ratio of <NUM>.

In a particular implementation of implant <NUM>, the surface area of non-resorbable framework <NUM> may be about fifty percent (<NUM>%) of the surface area of the entire implant <NUM>, while the surface area of resorbable component <NUM> may also be about fifty percent (<NUM>%). Further, the overall volume occupied by framework <NUM> may be about thirty percent (<NUM>%) of the volume of implant <NUM>, while the overall volume of resorbable component <NUM> may be about seventy percent (<NUM>%). In this configuration, the <NUM>%/<NUM>% surface area ratio results in a <NUM>% reduction in the peak stress that the device imparts to the vertebral body endplate when a <NUM>,<NUM> N load is applied, which results in a stress (<NUM> MPa) safely below the yield strength of bone (<NUM> MPa). In the absence of resorbable component <NUM>, the resulting stress to the vertebral endplate caused by framework <NUM> is about <NUM> MPa, which is well above the yield strength of bone and would be likely to result in unwanted subsidence of framework <NUM>. Thus, the particular combination of framework <NUM> and resorbable component <NUM> acts to decrease subsidence of implant <NUM> and encourage or allow bone formation and fusion to occur.

Implant <NUM> may be implanted into a disc space between adjacent vertebral bodies or as part of a corpectomy procedure in the same fashion as a traditional interbody device (IBD) or vertebral body replacement (VBR), respectively. Implant <NUM> allows for fusion to occur as resorbable material <NUM> is resorbed and replaced by newly-formed bone. Non-resorbable framework <NUM> acts as a structural scaffold or as a framework for resorbable material <NUM> to interface with. The non-resorbable framework <NUM> that contacts the vertebral end plates can also act to help the fusion process by, for example, being osteoconductive and/or incorporating resorbable coatings or resorbable materials within voids or pores of the non-resorbable material, etc., as described above. The particular configuration of resorbable and non-resorbable material in implant <NUM> therefore efficiently achieves fusion and bone formation, while providing ample structural support for adjacent vertebral bodies.

A particular manufacturing technique may also be used to construct implant <NUM> of <FIG> (or any of the other implants, discussed below). In an embodiment, polycaprolactone (PCL) is dissolved in Glacial Acetic Acid (GAA) at room temperature until homogenous. Bioactive glass is then added to the PCL-GAA solution under light agitation to prevent settling. Once thoroughly mixed, the solution is loaded into a syringe and extruded into a mold containing framework <NUM>. The filled mold is then injected with water and/or completely submerged in a water bath to precipitate the plastic onto the device. Once all of the PCL has precipitated, the filled implant <NUM> is removed from the mold.

Referring to <FIG>, an alternate implant <NUM> is shown that is similar to implant <NUM>. Due to the similarities between implants <NUM>, <NUM>, like numerals (within the <NUM>-series of numbers) refer to like elements in this embodiment and predominantly the differences between the embodiments will be discussed herein.

Implant <NUM> includes a structural, non-resorbable framework <NUM> and a resorbable component/material <NUM> positioned within and/or around framework <NUM>. As shown in <FIG>, framework <NUM> is similar to framework <NUM> of implant <NUM>, except that it includes left <NUM>, center <NUM>, and right <NUM> sections and a keyed opening <NUM> between the sections. Keyed openings <NUM> are formed along top and bottom surfaces <NUM>, <NUM> and extend from proximal end <NUM> to distal end <NUM> of framework <NUM>. In a particular embodiment, a first keyed opening <NUM> is positioned along top surface <NUM> between left <NUM> and center <NUM> sections, a second keyed opening <NUM> is positioned along top surface <NUM> between center <NUM> and right <NUM> sections, a third keyed opening <NUM> is positioned along bottom surface <NUM> between left <NUM> and center <NUM> sections, and a fourth keyed opening <NUM> is positioned along bottom surface <NUM> between center <NUM> and right <NUM> sections. Thus, a total of four (<NUM>) keyed openings <NUM> may be present in an embodiment.

Keyed openings <NUM> are shaped and arranged to receive a variety of arrow-shaped bone anchors as disclosed, for example, in Applicant's <CIT>. An example of an arrow-shaped bone anchor is shown in <FIG> as anchor <NUM>. An anchor very similar to anchor <NUM> is shown and described in connection with <FIG> of the '<NUM> Patent, and it is expressly contemplated that anchor <NUM> may include any of the features of the anchor of <FIG> of the '<NUM> Patent, or any other anchor disclosed in the '<NUM> Patent. Thus, anchor <NUM>, for example and not by way of limitation, can include an interconnection portion <NUM> extending from an anchor portion <NUM> for engaging with keyed openings <NUM>. Interconnection portion <NUM> may be dovetail-shaped in an embodiment to engage with a dovetail-shaped opening <NUM> in framework <NUM>. Further, although not shown herein, as described in the '<NUM> Patent anchor <NUM> may have a stop feature at its trailing end to ensure that anchor <NUM> does not travel too far into framework <NUM>. Anchor <NUM> may also have lock features for locking anchor <NUM> into engagement with framework <NUM> once fully inserted. Put simply, anchor <NUM> can include any of the features of any of the anchors of the '<NUM> Patent, and engage and be retained in framework <NUM> by the means described in the '<NUM> Patent. Anchor <NUM> can therefore provide an efficient means of securing implant <NUM> to adjacent vertebral bodies once implanted.

As shown in the particular implementation of anchor <NUM> in <FIG>, anchors <NUM> may be arranged to diverge and angle away from one another along top and bottom surfaces <NUM>, <NUM> of framework <NUM>, and thus implant <NUM>. However, any of the directional and/or angled configurations of anchors disclosed in the '<NUM> Patent could equally be used with framework <NUM>, and thus implant <NUM>.

Framework <NUM> also differs from framework <NUM> in that it is substantially devoid of struts and geometric openings, as present in framework <NUM>. Instead, vertical openings <NUM> are defined in top and bottom surfaces <NUM>, <NUM> of left <NUM>, center <NUM>, and right <NUM> sections of framework <NUM>, and lateral openings <NUM> are present as well. Further, framework <NUM> may be open between each support column <NUM> within the main body of framework <NUM>.

Resorbable component <NUM> is shown in detail in <FIG>. As resorbable component <NUM> is somewhat similar to resorbable component <NUM>, like numerals refer to like elements in this embodiment and predominantly the differences between components <NUM>, <NUM> will be discussed herein. Resorbable component <NUM> includes left <NUM>, center <NUM>, and right <NUM> sections to match left <NUM>, center <NUM>, and right <NUM> sections of framework <NUM>. Resorbable component <NUM> may be composed of a flowable material that is positioned within and/or around framework <NUM> during, for example, manufacturing. Alternatively, it may be possible to pre-construct resorbable component <NUM> and slide it into engagement with framework <NUM> through an opening in framework <NUM> (e.g., one of lateral openings <NUM>). Each of left <NUM>, center <NUM>, and right <NUM> sections of resorbable component <NUM> include a vertical opening <NUM> that is alignable with vertical openings <NUM> of framework <NUM>. Thus, once resorbable component <NUM> is positioned within and/or around framework <NUM>, vertical openings <NUM> of resorbable component <NUM> define openings in implant <NUM> that, in an embodiment, are sized to receive bone-graft material (e.g., for promoting fusion).

Resorbable component <NUM> also includes its own keyed openings <NUM> for aligning with keyed openings <NUM> of framework <NUM> and providing an interconnection mechanism between implant <NUM> and anchors <NUM>. In a particular embodiment, a first keyed opening <NUM> is positioned along top surface <NUM> of resorbable component <NUM> between left <NUM> and center <NUM> sections, a second keyed opening <NUM> is positioned along top surface <NUM> between center <NUM> and right <NUM> sections, a third keyed opening <NUM> is positioned along bottom surface <NUM> of resorbable component <NUM> between left <NUM> and center <NUM> sections, and a fourth keyed opening <NUM> is positioned along bottom surface <NUM> between center <NUM> and right <NUM> sections. Keyed openings <NUM>, like keyed openings <NUM>, may be of any shape, have any direction and/or angle, and include any of the features of such similar keyed openings as described in the '<NUM> Patent. Thus, keyed openings <NUM> engage with anchors <NUM> once resorbable component <NUM> is positioned within and/or around framework <NUM>.

Resorbable component <NUM> may also include engagement structures <NUM>, for example in the form of cutouts, arranged to engage with like engagement structures (not shown) in framework <NUM>. Such engagement structures <NUM> secure resorbable component <NUM> to framework <NUM>. Resorbable component <NUM> also includes an opening <NUM> for connection with an insertion tool that is alignable with like opening <NUM> in framework <NUM>. Openings <NUM>, <NUM> are, in an embodiment, threaded for engagement with a threaded portion of an implantation tool.

Although certain structures of framework <NUM> and/or resorbable component <NUM> are not discussed above, for example teeth <NUM>, <NUM> thereon, it is to be understood that such structures are encompassed in framework <NUM> and/or resorbable component <NUM> and are referenced in the figures by way of reference numerals that correspond or are like the reference numerals for framework <NUM> and resorbable component <NUM> of implant <NUM>. Additionally, it is to be understood that any of the materials disclosed for framework <NUM> and resorbable component <NUM> may be used to compose framework <NUM> and resorbable component <NUM>, and that resorbable component can be used as a structural member in an embodiment or a non-structural member in other embodiments. When used as a structural member, resorbable component <NUM> can act to assist with preventing or mitigating subsidence of framework <NUM> into adjacent vertebral bodies, a common downfall of current PEEK and/or titanium cages. Further, the surface area and volume percentages and ratios discussed above in connection with implant <NUM> can also be used with implant <NUM>.

Some beneficial aspects of implants <NUM>, <NUM> above include but are not limited to: (<NUM>) the addition of a resorbable component <NUM>, <NUM> that may, at least initially, act to distribute contact loads with bone in order to prevent failure of the bone due to high localized stresses (subsidence is a known potential failure mode of existing IBDs); (<NUM>) a particular balance of resorbable and non-resorbable structures that both meets overall implant structural requirements and results in minimizing the volume, location, and orientation of radiopaque non-resorbable structures to facilitate the use of radiographic imaging techniques to assess local anatomy and progress of a fusion mass; and/or (<NUM>) a combination of resorbable and non-resorbable regions able to interface with additional fixation elements in such a manner that fixation between the IBD and bone is not lost as material resorbs. Other benefits of implants <NUM>, <NUM> are clearly also experienced.

<FIG> depict another implant <NUM>, according to an embodiment of the present invention. Implant <NUM> includes a substantially non-structural, non-resorbable frame <NUM> used in connection with a structural, resorbable component <NUM> positioned within frame <NUM>. In this embodiment, certain like reference numerals refer to like elements but, due to the difference between implant <NUM> and implants <NUM>, <NUM>, no consistent numbering scheme is used.

Frame <NUM>, as shown in <FIG>, includes top and bottom bone-contacting surfaces <NUM>, <NUM> that, in an embodiment, are formed of a porous but non-resorbable material. Top and bottom surfaces <NUM>, <NUM> may be very thin in some instances (e.g., two millimeters (<NUM>) or less), and thus, top and bottom surfaces <NUM>, <NUM> alone are non-structural due to their thinness. Yet, when combined with structural resorbable component <NUM>, implant <NUM> is able to meet the demands of the post-surgical loads that are typically experienced while also encouraging fusion and resorption.

Frame <NUM> also includes proximal and distal ends <NUM>, <NUM> and an opening <NUM> for connection with an implantation tool (not shown) at proximal end <NUM>. Opening <NUM> is threaded in an embodiment to engage with a threaded portion of an implantation tool (not shown). Frame <NUM> has a bulleted nose <NUM> at its distal end <NUM>, and a vertical opening <NUM> through frame <NUM>'s top and bottom surfaces <NUM>, <NUM>. Frame <NUM> also includes a large lateral opening <NUM> sized to receive resorbable component <NUM>, as described below. An opposing lateral side of frame <NUM> is closed, as shown in cross section in <FIG>.

<FIG> show resorbable component <NUM> in various views. Resorbable component <NUM> may form a structural component for implant <NUM> and be composed of structural resorbable material. Any of the resorbable materials described in connection with implants <NUM>, <NUM> can be used for resorbable component <NUM>. Likewise, any of the materials and/or methods used to compose frameworks <NUM>, <NUM> of implants <NUM>, <NUM> can be used to construct frame <NUM> of implant <NUM>.

Resorbable component <NUM> of <FIG> includes top and bottom surfaces <NUM>, <NUM>, proximal and distal ends <NUM>, <NUM>, an implantation tool opening <NUM> in proximal end <NUM>, and a bulleted nose <NUM> at distal end <NUM>. A vertical opening <NUM> is also formed in resorbable component <NUM> through top and bottom surfaces <NUM>, <NUM>. In an embodiment, tool opening <NUM> is threaded for engagement with a threaded portion of an implantation tool (not shown). In addition, opening <NUM> may extend into the body of resorbable component <NUM> and open out into vertical opening <NUM>, such that opening <NUM> may form an injection port for injection of a fusion material into the body of resorbable component <NUM>. For instance, bone graft material may be injected into the body of resorbable component <NUM> through opening <NUM> so that such bone graft material is able to interface with adjacent vertebral bodies through vertical opening <NUM> and affect fusion. Resorbable component <NUM> also has engagement structures <NUM> that project outward from vertical opening <NUM>. Engagement structures <NUM> may interface with like engagement structures (not shown) on frame <NUM> to secure resorbable component <NUM> relative to frame <NUM>.

In use, resorbable component <NUM> may be slid into engagement with frame <NUM> through its lateral opening <NUM> so that engagement structures <NUM> of resorbable component <NUM> engage with like engagement structures (not shown) on frame <NUM> to secure resorbable component <NUM> relative to frame <NUM>. Alternatively, these components could be pre-assembled by other means such as molding, packing, thermal assembly, 3D printing, or interference fit. With resorbable component <NUM> in frame <NUM>, it can provide structural support for implant <NUM> and reinforce frame <NUM> (in particular frame <NUM>'s top and bottom bone-contacting surfaces <NUM>, <NUM>). Optionally, opening <NUM> in resorbable component <NUM> and opening <NUM> in frame <NUM> can be used as injection ports to inject a fusion material (e.g., bone graft) into resorbable component <NUM> for assisting with the fusion process. Since openings <NUM>, <NUM> align once resorbable component <NUM> is positioned in frame <NUM>, such openings <NUM>, <NUM> may act as an injection port in the above-described manner. In this regard, the implantation tool (not shown) used to connect with openings <NUM>, <NUM> and insert implant <NUM> into the intervertebral space may also have an injection conduit for injecting fusion material into resorbable component <NUM>. Thus, the implantation tool (not shown) could threadably connect with at least one of openings <NUM>, <NUM> and serve to also injection fusion material into resorbable component <NUM> through its injection conduit.

Although not shown, it is also contemplated that top and bottom surfaces <NUM>, <NUM> of frame <NUM> and top and bottom surfaces <NUM>, <NUM> of resorbable component <NUM> may be tapered towards one another to create a lordotic implant <NUM> for use in certain applications (e.g., in the lumbar spine where natural lordosis is present).

Implant <NUM>, due to the thin top and bottom surfaces <NUM>, <NUM> of frame <NUM> and the structural support provided by resorbable component <NUM>, may also act to increase graft loading over time. As an example, as resorbable component <NUM> resorbs and new bone is formed, the structural stiffness of implant <NUM> may be reduced. In this case, where a bone graft is used with implant <NUM> (e.g., in vertical opening <NUM> of resorbable component <NUM> or elsewhere), such a decrease in stiffness can lead to increased graft loading over time and improve the fusion process.

In a particular embodiment, non-resorbable frame <NUM> may be composed of a titanium alloy and resorbable component <NUM> of a resorbable material with mechanical properties similar to bone, such as CLM. In this embodiment, non-resorbable frame <NUM> may occupy one-hundred percent (<NUM>%) of the overall surface area in contact with the vertebral endplates, while resorbable component <NUM> may occupy zero percent (<NUM>%). In this instance, the pores of non-resorbable frame <NUM> are not filled with a resorbable material. Further, the volume of frame <NUM> may be thirty six percent (<NUM>%) of the overall volume of implant <NUM>, while the volume of resorbable component <NUM> may be sixty four percent (<NUM>%). A benefit of this volume ratio is that the overall stiffness of the device is primarily dictated by resorbable component <NUM>, which makes up a majority of the volume and also bears a majority of the service load in the cephalad/caudad direction. Another benefit of this configuration, as it relates to implant <NUM>, is that the radiopaque material (frame <NUM>) has been located such that there is no obstruction for imaging the fusion mass from a lateral direction.

<FIG> illustrate an implant <NUM>, according to yet another embodiment of the present invention. Implant <NUM> comprises a non-resorbable, non-structural framework <NUM> that has a fluid channel conduit(s) <NUM> and a structural, resorbable component <NUM> positioned around framework <NUM>. Due to the differences from previous embodiments, certain like numerals refer to like elements, but no consistent numbering scale is used in this embodiment.

As shown in <FIG>, framework <NUM> of implant <NUM> has a main body <NUM> that includes at least one conduit <NUM> therein. Framework <NUM> also has proximal and distal ends <NUM>, <NUM>, an injection port <NUM> at proximal end <NUM>, and a vertical opening <NUM> through main body <NUM>. Injection port <NUM> doubles as an implantation tool opening, and thus, it is threaded in an embodiment to engage with a threaded portion of an implantation tool (not shown). Injection port <NUM> is fluidly connected to conduit <NUM> so that fluid can be injected into port <NUM> and travel into and through conduit <NUM>. In an embodiment, conduit <NUM> traverses substantially an entire perimeter of main body <NUM> of framework <NUM>. Framework <NUM> also includes an enlarged portion <NUM> forming a step at its proximal end <NUM> and conduit <NUM> may traverse enlarged portion <NUM> until it intersects with and opens out into injection port <NUM>. In a particular embodiment, main body <NUM> is closed beyond injection port <NUM> so that, as fluid is forced into injection port <NUM>, it flows from port <NUM> and into conduit <NUM>.

In another embodiment, injection port <NUM> and conduit <NUM> can include any of the fittings and/or flow channels described in connection with Applicant's <CIT>, now <CIT> As an example, <FIG> of the '<NUM> Application depict an implant <NUM> with a threaded passage <NUM> and a flow channel <NUM> in fluid communication therewith. The structure of threaded passage <NUM> and flow channel <NUM> could be utilized in connection with framework <NUM> herein. Indeed, although not expressly described in this disclosure, it is to be appreciated that any of the flow channels (including multiple flow channels), fittings, passages therefor, and other structures of the implants taught in the '<NUM> Applicant can be used with framework <NUM> and/or resorbable component <NUM> herein. Applicant provides certain examples of the structures from the '<NUM> Application that could be used herein, but such examples are not to be taken as limiting and it should be recognized that any of the principles of the '<NUM> Application are usable with implant <NUM>.

Framework <NUM> of implant <NUM> also has a plurality of cylinders <NUM> projecting outward from main body <NUM>, which terminate in holes <NUM>. As described in more detail below, cylinders <NUM> extend through resorbable component <NUM> so that holes <NUM> are open to the exterior of implant <NUM>, much like the holes described in the '<NUM> Application. As shown in cross section in <FIG>, cylinders <NUM> each have a conduit <NUM> that is in fluid communication with conduit <NUM> of main body <NUM>. Thus, fluid can flow from conduit <NUM>, into each of conduits <NUM> of cylinders <NUM>, and ultimately to the exterior of implant <NUM> via holes <NUM>. As such, it is possible to inject fluid into implant <NUM> and have the fluid coat the exterior of implant <NUM>. As described in the '<NUM> Application, the fluid injected into implant <NUM> may be a biologic material, a therapeutic material, a bone cement, bone-growth promoting material, Bone Marrow Aspirate, antimicrobial material, bone morphogenic proteins ("BMP"), stem cells, solutions to assist in the resorption process, tissue-targeted glycosaminoglycans, or any other like material.

Resorbable component <NUM>, one side of which is shown in <FIG>, includes top and bottom surfaces <NUM>, <NUM>, proximal and distal ends <NUM>, <NUM>, a vertical opening <NUM>, and teeth <NUM> formed on top surface <NUM>. Resorbable component <NUM> may be composed of any of the resorbable materials discussed in connection with the previous implants <NUM>, <NUM>, <NUM> and, in an example, is a flowable material that is embedded within framework <NUM> during manufacturing. In this regard, framework <NUM> and its projecting cylinders <NUM> can act as a scaffold to retain resorbable component <NUM> in connection with framework <NUM>. Additionally, framework <NUM>, in its capacity as a scaffold, can provide support to resorbable component <NUM> so that component <NUM> does not crack or fracture during implantation. Indeed, resorbable materials are, in some existing implants, susceptible to fracture or cracking during implantation. As an example, allograft bone is often brittle during implantation.

Resorbable component <NUM> also has a series of holes <NUM> arranged to align with projecting cylinders <NUM> of framework <NUM> and allow fluid to exit holes <NUM> of such cylinders <NUM>. Fluid exiting holes <NUM> of cylinders <NUM> (and thus holes <NUM> of resorbable component <NUM>) may act to coat top surface <NUM> of resorbable component <NUM> and assist with the resorption and/or fusion process. Resorbable component <NUM> further includes, at its proximal end <NUM>, a stepped portion <NUM> shaped and arranged to engage with enlarged portion <NUM> of framework <NUM>. Although not shown, a second resorbable component <NUM> identical to that shown in <FIG> is usable with implant <NUM> on an opposing side of implant <NUM>.

While not described above, it is also contemplated that conduit <NUM> of framework <NUM> may, in addition to or as a substitute to directing fluid to an exterior of implant <NUM>, also be arranged to direct fluid to a location fully enclosed within resorbable component <NUM>. Such a conduit would be beneficial to deliver fluid (e.g., a resorptive-enhancing fluid) to a location within resorbable component <NUM>. It is also the case that conduit <NUM> (or multiple conduits if included) may direct fluid to other exterior parts of implant <NUM>, for example the sides or proximal and/or distal ends of implant <NUM>. In addition, if multiple conduits <NUM> are included with framework <NUM>, different materials can be directed to different portions of implant <NUM>. These types of conduits are disclosed in more detail in the '<NUM> Application.

<FIG> depict an implant <NUM>, according to another embodiment of the present invention. Implant <NUM> includes a non-structural, non-resorbable framework <NUM> and a structural, resorbable component <NUM> positioned within and/or around framework <NUM>. Due to the differences from previous embodiments, certain like numerals refer to like elements, but no consistent numbering scale is used in this embodiment.

As shown in <FIG>, framework <NUM> has first and second ring members <NUM>, <NUM> and struts <NUM> that connect ring members <NUM>, <NUM>. Struts <NUM> terminate in proximal and distal end plates <NUM>, <NUM> arranged on framework <NUM>. In an embodiment, proximal end plate <NUM> includes an implantation tool opening <NUM> that is optionally threaded for engagement with a threaded portion of an implantation tool (not shown). Framework <NUM>, via its ring members <NUM>, <NUM>, struts <NUM>, and end plates <NUM>, <NUM>, provides a scaffold for embedding resorbable component <NUM> within framework <NUM>. Although framework <NUM> is non-structural, in the sense that it does not support post-surgical loads directly, it provides strength and rigidity to implant <NUM> and resorbable component <NUM> thereof.

Resorbable component <NUM> is shown in <FIG> and includes a main body <NUM> having top and bottom bone-contacting surfaces <NUM>, <NUM>, proximal and distal ends <NUM>, <NUM>, an implantation tool opening <NUM> at proximal end <NUM>, and a vertical opening <NUM> formed through main body <NUM>. As with the previous embodiments, implantation tool opening <NUM> may or may not be threaded for engagement with a threaded portion of an implantation tool (not shown). Additionally, opening <NUM> may be in fluid communication with vertical opening <NUM> so that a fusion or another biologic material can be injected into opening <NUM> via a tool. Such a tool is disclosed, for example, in the '<NUM> Application and it is expressly contemplated that any tool of the '<NUM> Application is usable with implant <NUM>, as well as any of the previous implants.

Resorbable component <NUM> also includes teeth <NUM> on its top and bottom surfaces <NUM>, <NUM>, and may be composed of any of the resorbable materials hereinbefore described. In an embodiment, resorbable component <NUM> is preassembled on framework <NUM> at the point of manufacture and provides structural support for implant <NUM> in that it is capable of supporting the post-surgical loads borne on implant <NUM> after insertion into a patient. This type of implant configuration is particularly useful when the resorbable material is strong but brittle, as spinal implants are often impacted into place and must be able to withstand impact loads without fracturing or becoming damaged. With implant <NUM>, impaction loads are borne by framework <NUM> (e.g., at tool opening <NUM>/proximal end plate <NUM>), and thus, the resorbable material of resorbable component <NUM> is safe from fracture and/or other damage during implantation. Resorbable component <NUM> also resists fracture due to the support provided by framework <NUM> in its capacity as a scaffold.

In a particular embodiment, it is possible to modify framework <NUM> to also increase or decrease the overall stiffness of implant <NUM>. As an example, the components of framework <NUM> may be made thicker or thinner in certain locations (e.g., struts <NUM> and rings <NUM>, <NUM>) to increase or decrease the overall rigidity of framework <NUM>, and thus implant <NUM>. Different thickness frameworks <NUM>, and Finite Element Analyses related thereto, are shown in <FIG>. As reflected in those figures, a different stiffness is realized for implant <NUM> between the thicker and thinner frameworks <NUM>.

<FIG> depict various images of prototypes of frameworks <NUM>, <NUM>, <NUM>, <NUM>, <NUM> of implants <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. It is to be understood that any of these prototypes can be constructed using an additive manufacturing process, as hereinbefore disclosed. Additionally, each of the frameworks may be composed of any of the materials discussed in connection with any of the above-described frameworks. Further, other manufacturing methods (not claimed) such as injection molding processes may be used to construct frameworks <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. Thus, a variety of materials and manufacturing methods may be utilized to create frameworks <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. Certain particular features of the various prototypes will now be discussed.

Referring to all of the prototypes of <FIG>, it is seen that a porous and/or roughened layer or surface coating may be used on all, substantially all, or a majority of the exposed surfaces of frameworks <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. Such a coating could enhance the resorptive and/or fusion characteristics of a particular framework, make it more amenable to connection with a particular resorbable component or material, or simply increase the framework's resistance to migration in the intervertebral space once implanted.

Referring to the prototype of framework <NUM> of <FIG>, it is also seen that top and bottom bone-contacting surfaces <NUM>, <NUM> are highly porous and thin. Such surfaces <NUM>, <NUM>, as described above, are structurally supported by resorbable component <NUM>. Additionally, in the image of the prototype of framework <NUM>, it is shown that framework <NUM> can have multiple lateral openings for receiving resorbable component <NUM>, instead of only a single lateral opening <NUM>.

Turning to the prototype of framework <NUM> of <FIG>, it is shown in one of the prototypes (left) that a variety of differently-sized struts may be used in framework <NUM>. As an example, smaller struts may traverse between distal end plate <NUM> and second ring <NUM> and between proximal end plate <NUM> and first ring <NUM>. One or more side struts may also be used on framework <NUM>, as shown. Such side struts may be bowed and be connected to proximal end plate <NUM>, first ring <NUM>, second ring <NUM>, and finally distal end plate <NUM>. These additional struts may provide yet additional stiffness to implant <NUM> and/or act as a further scaffold for resorbable component <NUM>.

A surgical kit is also contemplated within the present invention. Due to the inability for many of the known resorbable materials to be properly sterilized via autoclave without being rendered unusable, it is expected that at least any of the resorbable components described above may be provided in a sterile package in the kit. This packaging could enclose either the entire finished implant (resorbable and non-resorbable components), or just the resorbable component with the intent to assemble intraoperatively. Indeed, although many of the implants discussed above are described as being assembled upon manufacturing, it is contemplated that resorbable and non-resorbable components of the above implants may be assembled in the operating room or in-situ. The in-situ assembly process could include first implanting the non-resorbable component into the spine, and then injecting or flowing a curable resorbable component through and/or around the non-resorbable portion/framework within the disc space. The resorbable component could then be allowed to cure/harden, at which point the implant may be left implanted for purposes of resorption of the resorbable material and fusion of the vertebral bodies. It is contemplated that such a process is possible with any of frameworks <NUM>, <NUM>, <NUM>, <NUM>, <NUM> of implants <NUM>, <NUM>, <NUM>, <NUM>, <NUM>.

The surgical kit may also include implants <NUM>, <NUM>, <NUM>, <NUM>, <NUM> of different sizes for use with different patients, and tools for the implantation of such implants. An example of such a tool is the tool disclosed in the '<NUM> Application, which is usable to insert some of the implants described previously and/or inject a biologic material into such implants.

Additionally, while no particular surgical approach has been discussed above in connection with implants <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and such implants are not limited to any particular surgical approach or use, it is contemplated that certain of the above implants may be more particularly suited for certain surgical applications. As an example, implants <NUM>, <NUM> may be suited for use as ALIF implants (anterior lumbar interbody fusion), implant <NUM> may be suited for use as a PLIF implant (posterior lumbar interbody fusion), and implants <NUM>, <NUM> may be suited for use as DLIF implants (direct lateral interbody fusion). Of course, the foregoing implants may be suitable for use in other areas of the spine and along different surgical approaches (e.g., anterolateral, transforaminal, etc.). As an example, the features and structures of the above implants may be suitable for use in cervical applications. The above-described uses and surgical approaches are therefore not to be taken as limiting and are merely exemplary. Likewise, the implants shown in the figures are merely examples of those which can be created according to the present invention. It is contemplated that other implant shapes/configurations can be made in accordance with the present invention.

In the devices shown in the figures, particular structures are shown as being adapted for use in the implantation of an implant according to the present invention. The invention also contemplates the use of any alternative structures for such purposes, including structures having different lengths, shapes, and/or configurations. For instance, although threaded connection mechanisms are taught herein (e.g., for insertion of the foregoing implants with an implantation tool), it is equally the case that non-threaded connection mechanisms can be used. For instance, a bayonetted connection, press-fit connection acting through dimensional interferences, luer connection, or other like locking connection may be used to implant any of implants <NUM>, <NUM>, <NUM>, <NUM>, <NUM> into the intervertebral space via an implantation tool with a like connection. This is particularly the case for implant <NUM> which, although it has a threaded, recessed opening <NUM>, may alternatively include any of the projecting luer fittings disclosed in the '<NUM> Application. Implant <NUM> is, of course, merely used as an example.

Further modifications and variants of the foregoing implants <NUM>, <NUM>, <NUM>, <NUM>, <NUM> are also contemplated. For instance, although certain of implants <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may not be described above as including lordotic bone-contacting surfaces, such a feature is expressly contemplated with each of implants <NUM>, <NUM>, <NUM>, <NUM>, <NUM> as an option. In particular, it is contemplated that any of implants <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may include lordotic surfaces (e.g., surfaces that taper towards one another) to accommodate natural lordosis that is present in certain areas of the spine. Some of implants <NUM>, <NUM>, <NUM>, <NUM>, <NUM> are shown in the figures with a lordotic taper, although that feature may not be expressly discussed above.

In addition, while discussed somewhat in connection with implant <NUM>, it is contemplated that such implant <NUM> may include multiple fluid conduits instead of the single conduit <NUM> shown in the figures. Such conduits may be fluidly isolated from one another to allow different fluids to be transferred to different parts of the implant, or the conduits may be fluidly connected. Additionally, certain fluid conduits may lead to areas wholly encompassed in resorbable component <NUM> instead of opening out to an exterior of implant <NUM>, as described above. Some of these and other features are taught in the '<NUM> Application, and it is to be understood that such features and/or structures are usable with implant <NUM>.

In a further example, although implant <NUM> is described as using a particular bone anchor <NUM>, it is contemplated that framework <NUM> and resorbable component <NUM> may be provided with more traditional bone-anchor features. For instance, framework <NUM> and resorbable component <NUM> may be provided with threaded holes for engaging with traditional threaded bone screws. Such holes may be arranged substantially as shown in connection with keyed openings <NUM>, <NUM> (e.g., the holes may number four (<NUM>) in total, and diverge outward so that bone screws are directed up/down into the vertebral bodies, and in an outward direction). If bone-screw holes are included, certain anti-backout features might also be provided. For instance, a movable protrusion may be provided in each hole that automatically moves in response to a bone screw being inserted into the hole, and snaps back once the bone screw has passed the protrusion so as to cover the particular bone screw. Such a mechanism could prevent backout of screws inserted into implant <NUM>. Other anti-backout mechanisms might also be used, such as traditional "man-hole covers," which are attached to the implant after the bone screws have been inserted and act to cover one or more of the bone screws.

In further variants, it is contemplated that any of implants <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may utilize the following surface area and/or volume ranges for the non-resorbable and resorbable components thereof:.

As yet another example, any of the resorbable components above may be combined with biologics and/or anti-infectives, including but not limited to bone marrow, blood, growth factors, proteins, peptides CAGs, antimicrobials, and/or antibiotics.

Claim 1:
An implant (<NUM>, <NUM>) sized and adapted for insertion into an intervertebral space between adjacent vertebral bodies comprising:
a non-resorbable, structural framework (<NUM>) having top (<NUM>) and bottom (<NUM>) bone-contacting surfaces and a plurality of struts (<NUM>) defining geometric openings (<NUM>) between the top (<NUM>) and bottom (<NUM>) bone-contacting surfaces, the struts (<NUM>) providing structural support for the framework (<NUM>); and
a resorbable material component (<NUM>) embedded within and/or around the framework (<NUM>) for resorption and formation of new bone to fuse the vertebral bodies together;
characterized in that the resorbable material component (<NUM>) is embedded within the struts (<NUM>) and has top (<NUM>) and bottom (<NUM>) bone-contacting surfaces, the top (<NUM>) and bottom (<NUM>) bone-contacting surfaces of the resorbable material component (<NUM>) being arranged to contact the vertebral endplates over a contact surface area such that the resorbable material component acts to distribute some contact loads between the implant and the vertebral bodies across an extent of the implant to reduce peak stresses between the framework (<NUM>) and the vertebral bodies, thereby reducing or eliminating subsidence of the framework (<NUM>) into the vertebral bodies;
and in that the implant (<NUM>, <NUM>) further comprises a bone anchor (<NUM>) having a bladed portion and a keyed interconnection portion (<NUM>), and the framework (<NUM>, <NUM>) includes at least one keyed opening (<NUM>) sized and shaped to receive the keyed interconnection portion (<NUM>).