Patent Description:
Many types of spinal irregularities can cause pain, limit range of motion, or injure the nervous system within the spinal column. These irregularities can result from, without limitation, trauma, tumor, disc degeneration, and disease. One example of a spinal irregularity that may result from disc degeneration is spinal stenosis, the narrowing of a spinal canal, which can result in the compression of spinal nerves such as the spinal cord or cauda equina. In turn, the nerve compression can result in pain, numbness, or weakness. Other examples of conditions that can result from disc degeneration are osteoarthritis and disc herniation.

Often, these irregularities can be treated by performing a discectomy and/or immobilizing a portion of the spine. For example, treatment can include a surgical procedure that involves removal and replacement of an affected intervertebral disc with a prosthesis and the subsequent fusion of adjacent vertebrae. The prosthesis, such as an interbody cage or spacer, may be used either alone or in combination with one or more additional devices such as rods, screws, and/or plates.

<CIT> describes a system known in the art.

According to the invention it is provided an explandable system having the features of the preamble of claim <NUM>. Further advantagfeous features of the invention are set forth in the dependent claims.

Some embodiments herein are directed to an expandable fusion system comprising an expandable spinal implant that can include a body member comprising a first end section, a second end section, and a cavity therebetween, the first end section comprising a first bore and the second end section comprising a second bore; a driving member comprising a tapered section at the distal end and disposed distal to the body member; a first endplate configured to engage the body member and the driving member; a second endplate configured to engage the body member and the driving member; and an actuator assembly comprising an actuation screw, the actuation screw comprising a head and a threaded body, wherein the head is configured to be completely contained between the first endplate and the second endplate.

Other embodiments herein are directed to an expandable fusion system comprising an expandable spinal implant that can include a body member comprising a first end section, a second end section, and a cavity therebetween, the first end section comprising a first bore and the second end section comprising a second bore; a driving member comprising a threaded bore and a tapered outer surface; a first endplate configured to engage the body member and the driving member; a second endplate configured to engage the body member and the driving member; and an actuator assembly comprising an actuation screw, the actuation screw comprising a head and a threaded body, wherein the head is configured to engage the first end section of the body member and the threaded body is configured to engage the threaded bore of the driving member.

Yet other embodiments herein are directed to an expandable fusion system that can include an expandable spinal implant and an inserter, the expandable spinal implant comprising a body member comprising a first end, a second end, and a cavity therebetween, the first end comprising a first bore and the second end comprising a second bore; a driving member comprising a threaded bore and a tapered outer surface; a first endplate configured to engage the body member and the driving member; a second endplate configured to engage the body member and the driving member; an actuator assembly comprising an actuation screw, the actuation screw comprising a head and a threaded body; and the inserter configured to reversibly engage the body member, the inserter comprising a driver configured to be received within the body member and comprising an insertion portion having a length that is equal to at least <NUM>% of a length of the expandable spinal implant.

Some embodiments herein are directed to an expandable fusion system comprising an expandable spinal implant that can include a body member comprising a first end section, a second end section, and a cavity therebetween, the first end section comprising a first bore and the second end section comprising a second bore; a first driving unit; a second driving unit configured to pivot relative to the first driving unit; a first endplate configured to engage the first driving unit; a second endplate configured to engage the second driving unit; and an actuator assembly comprising a nut and an actuation screw.

Other embodiments herein are directed to an expandable fusion system comprising an expandable spinal implant that can include a body member comprising a first end section, a second end section, and a cavity therebetween, the first end section comprising a first bore and the second end section comprising a second bore; a first driving unit; a second driving unit; a first endplate configured to engage the first driving unit and pivot relative to the body member; a second endplate configured to engage the second driving unit and pivot relative to the body member; and an actuator assembly comprising a nut and an actuation screw.

Yet other embodiments herein are directed to an expandable fusion system that can include an expandable spinal implant and an inserter, the expandable spinal implant comprising a body member comprising a first end section, a second end section, and a cavity therebetween, the first end section comprising a first bore and the second end section comprising a second bore; a first driving unit; a second driving unit; a first endplate configured to engage the first driving unit; a second endplate configured to engage the second driving unit; and an actuator assembly comprising a nut and an actuation screw; and an inserter configured to reversibly engage the body member, the inserter comprising a driver configured to be received within the body member and comprising an insertion portion having a length that is equal to at least <NUM>% of a length of the expandable spinal implant.

Further areas of applicability of the present disclosure will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating certain embodiments, are intended for purposes of illustration only and are not intended to limit the scope of the disclosure.

According to a further aspect of the invention it is provided an expandable fusion system comprising an expandable spinal implant, comprising: a body member comprising a first end section, a second end section, and a cavity therebetween, the first end section comprising a first bore and the second end section comprising a second bore; a driving member comprising a threaded bore and a tapered outer surface; a first endplate configured to engage the body member and the driving member; a second endplate configured to engage the body member and the driving member; and an actuator assembly comprising an actuation screw, the actuation screw comprising a head and a threaded body, wherein the head is configured to engage the first end section of the body member and the threaded body is configured to engage the threaded bore of the driving member.

In a version, the first end section of the body member comprises a first mating element configured to engage the first endplate and a second mating element configured to engage the second endplate.

In another version, the second end section of the body member comprises a first mating element configured to engage the first endplate and a second mating element configured to engage the second endplate.

In a further version, the tapered outer surface of the driving member is located at a first end thereof. Advantageously, the driving member further comprises a second end, the second end comprising a first mating element configured to engage the first endplate and a second mating element configured to engage the second endplate.

According to a further aspect of the invention it is provided an expandable fusion system, comprising: an expandable spinal implant, comprising: a body member comprising a first end, a second end, and a cavity therebetween, the first end comprising a first bore and the second end comprising a second bore; a driving member comprising a threaded bore and a tapered outer surface; a first endplate configured to engage the body member and the driving member; a second endplate configured to engage the body member and the driving member; an actuator assembly comprising an actuation screw, the actuation screw comprising a head and a threaded body; and an inserter configured to reversibly engage the body member, the inserter comprising a driver configured to be received within the body member and comprising an insertion portion having a length that is equal to at least <NUM>% of a length of the expandable spinal implant.

In a version, the inserter further comprises: an outer sleeve comprising a first end configured to engage the body member of the expandable implant; and an inner sleeve comprising exterior threads at a first end thereof.

In a version the outer sleeve comprises at least one countertorque tab extending from a first end thereof.

In a further version the inner sleeve is configured to be rotatably received within the outer sleeve.

In another version the driver is configured to be rotatably received within the inner sleeve.

In a version the length of the insertion portion of the driver is equal to at least <NUM>% of the length of the expandable spinal implant.

The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein the invention is showin in particular in <FIG>, the remaining figures aree reported for a better understanding of the invention:.

In a spinal fusion procedure, affected tissue between adjacent vertebrae may be removed and replaced with a prosthesis, such as an interbody cage, spacer, or other spinal implant. The intervertebral disc space can be accessed via various approaches (e.g., anterior, posterior, transforaminal, and/or lateral). To encourage bone growth, the prosthesis may be used in conjunction with bone graft material (e.g., bone chips, demineralized bone matrix, and/or bone morphogenetic proteins). The bone graft material may be packed into hollow areas of the prosthesis. In use, the prosthesis may be designed such that it is pre-packed with bone graft material prior to insertion into the intervertebral space. In contrast, the devices disclosed herein may be advantageously configured to enable backfilling of bone graft material after insertion into the intervertebral space. Those skilled in the art may appreciate that backfilling, rather than prefilling, the device may enable more bone graft material to be inserted, thereby promoting spinal fusion more effectively. Additionally, the bone graft material may be delivered through the same insertion tool used to insert the device into the intervertebral space. In use, the installation technique of the devices described herein may be simpler and/or more streamlined as compared to other techniques that require a separate tool to deliver bone graft material.

Embodiments herein are directed to spinal implants that may be configured for insertion between adjacent vertebrae for use in, e.g., spinal fusion procedures. The spinal implants may be configured for insertion anywhere along a spinal column, such as between lumbar, thoracic, and/or cervical vertebrae. In some embodiment, the spinal implants described herein may be configured for insertion using a minimally-invasive procedure (e.g., through a cannula). They may be configured for insertion along a variety of approaches, such as transforaminal, posterior, lateral, and/or anterior. For example, in some embodiments, the implants described herein may be configured for insertion at an angle in the range of from about <NUM>° to about <NUM>° relative to a direct posterior approach. In some embodiments, the length of the spinal implant may be in the range of from about <NUM> to about <NUM>. In other embodiments, the width of the spinal implant may be in the range of from about <NUM> to about <NUM>.

Some embodiments herein may be directed to expandable spinal implants. The expandable spinal implants described herein may have a variable height and may be configured to collapse to a smaller height prior to insertion and/or expand to a larger height after insertion. In some embodiments, the expanded height can be from about <NUM>% to about <NUM>% greater than the collapsed height. In other embodiments, the expanded height can be from about <NUM>% to about <NUM>% greater than the collapsed height. In yet other embodiments, the expanded height can be at least about <NUM>% greater than the collapsed height. In some embodiments, the collapsed height can be in the range of from about <NUM> to about <NUM>, and/or the expanded height can be in the range of from about <NUM> to about <NUM>. In other embodiments, the expanded height can be from about <NUM> to about <NUM> greater than the collapsed height.

In some embodiments, the expandable vertebral fusion devices may also have a variable lordotic angle. These devices may include one or more members configured to pivot about a pivot point. These devices may be configured to collapse to a smaller angle (e.g., <NUM>°) prior to insertion and/or expand to a larger angle (e.g., <NUM>°) after insertion. Accordingly, these devices may be configured for use in minimally-invasive surgery (MIS). For example, they may be inserted through a relatively small incision and/or through a cannula, thereby reducing trauma to the patient. Conversely, the expandable vertebral fusion devices described herein may be configured to expand to a height greater than that of other implants in the art, without requiring a larger incision. Furthermore, the height and/or lordotic angle of the expandable vertebral fusion devices may be adjusted after insertion, thereby providing a customized fit within the intervertebral space.

Components of all of the devices and systems disclosed herein can be made of materials known to those skilled in the art, including metals (e.g., titanium), metal alloys (e.g., stainless steel, titanium alloys, and/or cobalt-chromium alloys), ceramics, polymers (e.g., poly ether ether ketone (PEEK), polyphenylene sulfone (PPSU), polysulfone (PSU), polycarbonate (PC), polyetherimide (PEI), polypropylene (PP), polyacetals, or mixtures or co-polymers thereof), allograft, and/or combinations thereof. In some embodiments, the systems and devices may include radiolucent and/or radiopaque materials. In other embodiments, one or more components may be coated with a bone growth-enhancing material, such as hydroxyapatite. The components can also be machined and/or manufactured using techniques known to those skilled in the art. For example, polymeric components may be injection-molded or blow-molded. Additionally, the devices disclosed herein may be used together with materials that encourage bone growth, such as bone graft material, demineralized bone matrix, bone chips, and/or bone morphogenetic proteins. In some embodiments, these materials may advantageously be packed into hollow areas of the devices described herein.

As described herein, the spinal implants of the present disclosure may be configured for placement between two adjacent vertebrae, for example, as part of a spinal fusion procedure. These spinal implants may be referred to as, without limitation, interbody spacers, interbody fusion devices, vertebral fusion devices, interbody cages, and/or intervertebral cages. Each of the spinal implants described herein may include a superior and/or inferior surface (e.g., on the endplates described herein) that is configured to engage and/or contact a vertebral endplate or other vertebral surface. In some embodiments, the superior and/or inferior surfaces may be convex, corresponding to the topography of the vertebral surface. Accordingly, in some embodiments, the superior and/or inferior surfaces may be curved along a path that is offset from a longitudinal and/or transverse axis thereof. Additionally, the superior and/or inferior surfaces of each of the spinal implants described herein may include one or more texturizing members. Examples of such texturizing members include, but are not limited to, projections, bumps, teeth, grooves, peaks, spikes, and/or knurling. These texturizing features may advantageously enhance the interaction or fiction, and/or reduce movement, between the implant and the vertebrae.

Those skilled in the art may appreciate that directional terms such as "anterior," "posterior," "superior," "inferior," "leading," "trailing," "top," "bottom," and the like may be used herein for descriptive purposes and do not limit the orientation(s) in which the devices may be used. For example, those skilled in the art may appreciate that, in use, a "superior" surface may be installed adjacent an inferior vertebra, and vice versa. Accordingly, a feature described as being on top may actually be oriented towards the bottom after installation.

Turning now to <FIG>, some embodiments herein are directed to an expandable fusion system that can include an expandable spinal implant <NUM>. As illustrated in <FIG>, the expandable spinal implant <NUM> can include a first end <NUM>, a second end <NUM>, a first side <NUM>, and a second side <NUM>. As illustrated in <FIG>, the expandable spinal implant <NUM> can include a body member <NUM>, a driving member <NUM>, a first endplate <NUM>, and/or a second endplate <NUM>. As illustrated in <FIG>, the body member <NUM> can include a first end <NUM> having a first end section <NUM>, and a second end <NUM> having a second end section <NUM>. The body member <NUM> also includes a cavity <NUM> between the first and second end sections <NUM>, <NUM>. The first end section <NUM> is referred to as the leading and/or distal end section. The second end section <NUM> may be referred to as the trailing and/or proximal end section.

As illustrated in <FIG>, the first end section <NUM> can include a first bore <NUM> and the second end section <NUM> can include a second bore <NUM>. The first and second bores <NUM>, <NUM> can define an elongate channel extending longitudinally through the body member <NUM>. As illustrated in <FIG>, the first and second bores <NUM>, <NUM> can be coaxial along longitudinal axis <NUM> of the body member <NUM>. The first bore <NUM> may be non-threaded (e.g., smooth). In some embodiments, it can include a circumferential groove <NUM>. The first bore <NUM> can have a constant or variable diameter. In some embodiments, the first bore <NUM> can include a first section having a first diameter and a second section having a second diameter that is different than the first diameter. For example, the first bore <NUM> can include a reduced-diameter section <NUM> located at the first end <NUM> of the body member <NUM>. The second bore <NUM> may be threaded. The second bore <NUM> may be configured to threadably engage an insertion tool (e.g., inserter <NUM>) as described further herein. The second bore <NUM> may also be configured to receive bone graft material therethrough.

As illustrated in <FIG>, the body member <NUM> can also include a first side wall <NUM> and a second side wall <NUM>. Each of the first and second side walls <NUM>, <NUM> can extend from the first end section <NUM> to the second end section <NUM>. As illustrated in <FIG>, the cavity <NUM> can be defined between and/or bounded by the first end section <NUM>, second end section <NUM>, first side wall <NUM>, and second side wall <NUM>. The second end section <NUM> can also include one or more tool-engagement feature(s) <NUM>, such as a notch, cut-out, or groove. Each tool-engagement feature <NUM> may be configured to engage an insertion tool (e.g., outer sleeve <NUM>) as described further herein. In some embodiments, the body member <NUM> can include two or more tool-engagement features <NUM>. As illustrated in <FIG>, the body member <NUM> can include a first tool-engagement feature on the first side wall <NUM> and a second tool-engagement feature on the second side wall <NUM>.

The body member <NUM> can include one or more mating elements. Each of the mating elements may be configured (e.g., shaped) to mate with a complementary mating element on the first and/or second endplates <NUM>, <NUM>, as described herein. As illustrated in <FIG>, the body member <NUM> (e.g., first end section <NUM> and/or second end section <NUM>) can include at least a first mating element at a third (e.g., top and/or superior) side <NUM> and at least a second mating element at a fourth (e.g., bottom and/or inferior) side <NUM>. The first mating element can be configured to engage the first endplate <NUM> and the second mating element can be configured to engage the second endplate <NUM>. In some embodiments, the first end section <NUM> can include two mating elements <NUM>, <NUM> at the third side <NUM> and two mating elements <NUM>, <NUM> at the fourth side <NUM>. The second end section <NUM> can include two mating elements <NUM>, <NUM> at the third side <NUM>, illustrated in <FIG>, and two mating elements (not shown) at the fourth side <NUM>. Each mating element can be ramped (e.g., angled, inclined, and/or declined), and/or can include a ramped member. In some embodiments, one or more mating elements on the body member <NUM> can include a protrusion (e.g., a tongue, rail, and/or shoulder). In other embodiments, one or more mating elements on the body member <NUM> can include a recess (e.g., a groove, track, and/or channel). In some embodiments, the mating element can include an extension member. For example, as illustrated in <FIG>, mating element <NUM> can include a groove <NUM> and an extension tab <NUM> that can at least partially protrude into the groove. Those skilled in the art may appreciate the groove <NUM> may be configured to receive a portion of a mating element of the first endplate <NUM> therein. Additionally, the tab <NUM> may provide enhanced engagement with the first endplate <NUM> thereby reducing movement, separation, and/or decoupling between the first endplate <NUM> and body member <NUM> when in use. As illustrated in <FIG>, mating elements <NUM>, <NUM>, and/or <NUM> may include a groove and a tab. In other embodiments, any and/or all mating elements of the body member <NUM> can include a groove and a tab. In yet other embodiments, the mating element can include a protrusion and an engagement receptacle that overlaps the protrusion.

As described further herein, each mating element may have substantially similar inclinations, when in an assembled configuration, as their corresponding complementary mating elements on the first and/or second endplates <NUM>, <NUM>. In some embodiments, each mating element on the third side <NUM> (e.g., mating elements <NUM>, <NUM>, <NUM>, and/or <NUM>) can be inclined longitudinally from the first end <NUM> towards the second end <NUM> of the body member <NUM>. In other embodiments, each mating element on the fourth side <NUM> can be declined longitudinally from the first end <NUM> towards the second end <NUM> of the body member <NUM>. In other embodiments, the mating elements on the third side and the mating elements on the fourth side may diverge from each other along longitudinal axis <NUM> from a position relatively adjacent to the first end <NUM> to a position relatively adjacent to the second end <NUM>. In yet other embodiments, the mating elements on the body member <NUM> may be angled away from the longitudinal axis <NUM>, e.g., towards the second end <NUM>.

The driving member <NUM> is configured to engage the first and/or second endplates <NUM>, <NUM>. When in an assembled configuration, the driving member <NUM> is located distal to the body member <NUM> (e.g., closer to the first end <NUM> than the second end <NUM>), as illustrated in <FIG>. The driving member <NUM> can include a first (e.g., leading and/or distal) end <NUM> and a second (e.g., trailing and/or proximal) end <NUM>, as illustrated in <FIG>. As illustrated in <FIG>, the driving member <NUM> can also include a first side <NUM>, a second side <NUM>, a third (e.g., top and/or superior) side <NUM>, and a fourth (e.g., bottom and/or inferior) side <NUM>. The driving member <NUM> can include a width that is generally equal to a width of the body member <NUM>. The driving member <NUM> can include a tapered section. The tapered section may be located at the first end <NUM> of the driving member <NUM>. The tapered section can have a variable height. For example, as illustrated in <FIG>, at least a portion of the driving member <NUM> can have a height that decreases towards the first end <NUM>. As illustrated in <FIG>, the driving member <NUM> can include a single bore, such as central threaded bore <NUM>. The bore <NUM> may extend longitudinally through the driving member <NUM>. The bore <NUM> may be coaxial with a central longitudinal axis <NUM> of the driving member. When in an assembled configuration, the bore <NUM> can be coaxial with the first and/or second bores <NUM>, <NUM> of the body member <NUM>. The bore <NUM> may be configured to threadably engage the threaded body of the actuation screw <NUM> as described further herein.

The driving member <NUM> can include one or more mating elements. The mating element(s) can be generally located at the second end <NUM> of the driving member <NUM>. In some embodiments, the driving member <NUM> can include at least one mating element at (e.g., extending from and/or adjacent to) the third side <NUM> and at least one mating element at (e.g., extending from and/or adjacent to) the fourth side <NUM>. Those skilled in the art may appreciate that the mating element(s) at the third side <NUM> may be configured to engage the first endplate <NUM> and the mating element(s) at the fourth side <NUM> may be configured to engage the second endplate <NUM>. In other embodiments, the driving member <NUM> can include at least one mating element at the first side <NUM> and at least one mating element at the second side <NUM>. As illustrated in <FIG>, the second end <NUM> can include first mating element <NUM>, second mating element <NUM>, third mating element <NUM>, and fourth mating element <NUM>. The first and third mating elements <NUM>, <NUM> may be located at the third side <NUM>. Mating element <NUM> may be adjacent to the first side <NUM> and mating element <NUM> may be adjacent to the second side <NUM> of the driving member <NUM>. The second and fourth mating elements <NUM>, <NUM> may be located at the fourth side <NUM>. Mating element <NUM> may be adjacent to the first side <NUM> and mating element <NUM> may be adjacent to the second side <NUM> of the driving member <NUM>.

Each mating element can be configured (e.g., shaped) to mate with a complementary mating element on the first and/or second endplates <NUM>, <NUM> as described herein. The mating elements on the driving member <NUM> can include some or all of the features of the mating elements on the body member <NUM>. Each mating element can be ramped (e.g., angled, inclined, and/or declined), and/or can include a ramped member. In some embodiments, one or more mating elements on the driving member <NUM> can include a protrusion (e.g., a tongue, rail, and/or shoulder). In other embodiments, one or more mating elements on the driving member <NUM> can include a recess (e.g., a groove, track, and/or channel). In some embodiments, one or more mating elements can include a groove and a tab that can at least partially protrude into the groove, as described herein with respect to the body member <NUM>. Those skilled in the art may appreciate the groove may be configured to receive a tab of a mating element of the first and/or second endplates <NUM>, <NUM>. The tab may provide enhanced engagement with the first endplate <NUM> thereby reducing movement, separation, and/or decoupling between the first endplate <NUM> and body member <NUM> when in use.

As described further herein, each mating element of the driving member <NUM> may have substantially similar inclinations, when in an assembled configuration, as their corresponding complementary mating elements on the first and/or second endplates <NUM>, <NUM>. In some embodiments, each mating element on the third side <NUM> (e.g., mating elements <NUM> and/or <NUM>) can be inclined longitudinally from the second end <NUM> towards the first end <NUM> of the driving member <NUM>. In other embodiments, each mating element on the fourth side <NUM> can be declined longitudinally from the second end <NUM> towards the first end <NUM> of the driving member <NUM>. In other embodiments, the mating elements on the third side <NUM> and the mating elements on the fourth side <NUM> may diverge from each other along longitudinal axis <NUM> from a position relatively adjacent to the second end <NUM> to a position relatively adjacent to the first end <NUM>. In yet other embodiments, the mating elements on the driving member <NUM> may be angled relative to the longitudinal axis <NUM>, e.g., towards the first end <NUM>.

The first and/or second endplates <NUM>, <NUM> are configured to engage the body member <NUM> and the driving member <NUM>. In use, the expandable implant <NUM> may be oriented such that the first endplate <NUM> is the top, superior, and/or upper endplate and the second endplate <NUM> is the bottom, inferior, and/or lower endplate. First endplate <NUM> and second endplate <NUM> may include some or all of the same features. Those skilled in the art may appreciate that the description of the first endplate <NUM> herein may be applied to the second endplate <NUM> unless stated otherwise.

First endplate <NUM> can be configured to slideably and/or movably engage the body member <NUM> and/or the driving member <NUM>. As illustrated in <FIG>, first endplate <NUM> can include a first (e.g., leading and/or distal) end <NUM>, a second (e.g., trailing and/or proximal) end <NUM>, a first side <NUM>, and a second side <NUM>. The first endplate <NUM> can include a length between the first and second ends <NUM>, <NUM>, and a width between the first and second sides <NUM>, <NUM>. As illustrated in <FIG>, the first endplate <NUM> can also include a third (e.g., outer) side <NUM> and a fourth (e.g., inner) side <NUM>. As illustrated in <FIG>, the first endplate <NUM> can also include a through-hole <NUM> that passes from the outer side <NUM> to the inner side <NUM>. The through-hole <NUM> can be configured to enable bone graft material deposited within the expandable implant <NUM> to engage, contact, and/or fuse with an adjacent vertebral body. The outer side <NUM> may be configured to engage a vertebral body. The outer side <NUM> may be referred to as an outer surface and/or a superior surface. As illustrated in <FIG>, the outer side <NUM> can include a plurality of protrusions (e.g., bumps, teeth, and/or peaks) configured to retain the implant <NUM> within an intervertebral space. The outer side <NUM> can be generally planar, concave, and/or convex.

In some embodiments, inner side <NUM> can include at least one wall segment extending therefrom. Each wall segment may extend partially or completely along the length of the first endplate <NUM>. As illustrated in <FIG>, the first side <NUM> can include at least one wall segment and the second side <NUM> can include at least one wall segment. In some embodiments, the first side <NUM> and/or the second side <NUM> can include a plurality of overlapping and/or staggered wall segments. The wall segments may be staggered along the length and/or width of the first endplate <NUM>. For example, as illustrated in <FIG>, the second side <NUM> can include an outer wall segment <NUM> and an inner wall segment <NUM>. As illustrated in <FIG>, the first side <NUM> can include an outer wall segment <NUM> and an inner wall segment <NUM> separated by a gap <NUM>. The overlapping and/or staggered wall segments can advantageously enable the first and second endplates <NUM>, <NUM> to overlap, thereby reducing the height of the expandable implant <NUM> when in a collapsed configuration, for example, as illustrated in <FIG>.

The first endplate <NUM> can include one or more mating elements. In some embodiments, one or more mating elements of the first endplate <NUM> can include a protrusion (e.g., a tongue, rail, and/or shoulder). In other embodiments, one or more mating elements of the first endplate <NUM> can include a recess (e.g., a groove, track, and/or channel). In some embodiments, at least one mating element can include an extension member. For example, at least one of the mating elements can a groove and an extension tab that can at least partially protrude into the groove. As another example, the mating element can include a protrusion and an engagement receptacle that overlaps the protrusion. The mating element(s) on the first endplate <NUM> can be configured to form a slidable joint with complementary mating element(s) on the body member <NUM> and/or the driving member <NUM>. Accordingly, the body member <NUM> and/or the driving member <NUM> may be configured to slideably engage the first endplate <NUM>. The slideable joint may advantageously enable the expandable implant <NUM> to transition reversibly between expanded and contracted configurations. The slidable joint may include, for example, a tabled splice joint, a dovetail joint, a tongue and groove joint, or another suitable joint. In some embodiments, one or more mating elements on the first endplate <NUM> can include a recess (e.g., a groove, track, and/or channel), and one or more mating elements on the body member <NUM> and/or the driving member <NUM> can include a protrusion (e.g., a tongue, rail, and/or shoulder) configured to slide within the groove. In other embodiments, one or more mating elements on the first endplate <NUM> can include a protrusion and one or more mating elements on the body member <NUM> and/or the driving member <NUM> can include a recess.

In some embodiments, the mating elements may be located on and/or extend from the inner side <NUM>. In some embodiments, at least one mating element may be located on a wall segment. In other embodiments, the first side <NUM> can include at least one mating element and the second side <NUM> can include at least one mating element. In yet other embodiments, the first and/or second sides <NUM>, <NUM> can each include a mating element at the first end <NUM>, a mating element at an intermediate portion, and a mating element at the second end <NUM>. As illustrated in <FIG>, the first endplate <NUM> can include a first mating element <NUM>, a second mating element <NUM>, a third mating element <NUM>, a fourth mating element <NUM>, a fifth mating element <NUM>, and/or a sixth mating element <NUM>. The first, second, and third mating elements <NUM>, <NUM>, <NUM> may be located at the first side <NUM> and the fourth, fifth, and sixth mating elements <NUM>, <NUM>, <NUM> may be located at the second side <NUM> of the first endplate <NUM>. Furthermore, the first and/or fourth mating elements <NUM>, <NUM> may be adjacent to the first end <NUM> of the first endplate <NUM>, the second and/or fifth mating elements <NUM>, <NUM> may be adjacent to the intermediate portion of the first endplate <NUM>, and the third and/or sixth mating elements <NUM>, <NUM> may be adjacent to the second end <NUM> of the first endplate <NUM>. The mating elements on the first side <NUM> can be separated from corresponding mating elements on the second side <NUM> by a distance (e.g., width). In some embodiments, each mating element on the first side <NUM> may be separated from a complementary mating element on the second side <NUM> by the same distance. In other embodiments, for example, as illustrated in <FIG>, the third and sixth mating elements <NUM>, <NUM> may be separated by a distance that is less than the distance separating the first and fourth mating elements <NUM>, <NUM> and/or the second and fifth mating elements <NUM>, <NUM>.

The first and fourth mating elements <NUM>, <NUM> may each be configured to engage a complementary mating element on the driving member <NUM>. The other mating elements may each be configured to engage a complementary mating element on the body member <NUM>. Accordingly, each mating element can be ramped (e.g., angled, inclined, and/or declined), and/or can include a ramped member. The mating elements on the first endplate <NUM> may have substantially similar inclinations, when in an assembled configuration, as their corresponding complementary mating elements on the driving member <NUM> and/or body member <NUM>. As illustrated in <FIG>, first and fourth mating elements <NUM>, <NUM> of the first endplate <NUM> may be angled (e.g., inclined or declined) away from the outer side <NUM> in a direction from the first end <NUM> towards the second end <NUM>. The second, third, fifth, and/or sixth mating elements <NUM>, <NUM>, <NUM>, <NUM> of the first endplate <NUM> may be angled (e.g., inclined or declined) away from the outer side <NUM> in a direction from the second end <NUM> towards the first end <NUM> (e.g., in a direction opposite the first and/or fourth mating elements <NUM>, <NUM>). Those skilled in the art may appreciate, for example, that the first and second mating elements <NUM>, <NUM> may be angled in opposing directions and/or may extend along intersecting axes. In contrast, the second and third mating elements <NUM>, <NUM> may extend along generally parallel axes.

As illustrated in <FIG>, the expandable spinal implant <NUM> can include an actuator assembly <NUM>. The actuator assembly <NUM> can include an actuation screw <NUM>. In some embodiments, the actuator assembly <NUM> can also include a snap ring <NUM> and/or a washer <NUM>. The actuation screw <NUM> can include a head <NUM> and a threaded body <NUM>. The head <NUM> can be configured to be completely contained between the first and second endplates <NUM>, <NUM> when the expandable spinal implant <NUM> is in an assembled configuration, as illustrated in <FIG>. The head <NUM> may be configured to engage the first end section <NUM> of the body member <NUM>. For example, the head <NUM> can be configured to be received within the first bore <NUM> of the body member <NUM>. In some embodiments, the head <NUM> can include a diameter that is greater than a diameter of the reduced-diameter section <NUM> of the first bore. The threaded body <NUM> can include an outer diameter that is less than the diameter of the reduced-diameter section <NUM>. The threaded body <NUM> can be configured to engage the driving member <NUM>. For example, the threaded body <NUM> may be configured to threadably engage the central threaded bore <NUM> of the driving member <NUM>. The head <NUM> can include a tool-engagement feature, such as a recess or socket. The tool-engagement feature may be configured to engage a driver as described herein. As illustrated in <FIG>, the head <NUM> can include a circumferential groove <NUM>. The circumferential groove <NUM> can be configured to receive the snap ring <NUM> therein. The circumferential groove <NUM> of the actuation screw <NUM> may be longitudinally aligned with the circumferential groove <NUM> of the body member <NUM>. Accordingly, both circumferential grooves <NUM>, <NUM> may be configured to receive at least a portion of the snap ring <NUM> therein. Those skilled in the art may appreciate that in use, the snap ring <NUM> may advantageously retain the actuation screw <NUM> within the body member <NUM>. The washer <NUM> may have an outer diameter generally less than or equal to the diameter of the first bore <NUM>, and may have an inner diameter generally greater than or equal to the diameter of the reduced-diameter section <NUM> of the first bore <NUM>. The washer <NUM> may be configured to receive the threaded body <NUM> of the actuation screw <NUM> therethrough. The washer <NUM> may be configured to be received within the first bore <NUM> of the body member <NUM>. In use, the washer <NUM> may be positioned between the head <NUM> of the actuation screw <NUM> and the body member <NUM>, and may advantageously provide a bearing surface for the actuation screw <NUM>.

In use, the expandable spinal implant <NUM> may advantageously be configured to reversibly transition between a collapsed configuration and an expanded configuration. In the collapsed configuration, for example, as illustrated in <FIG>, the expandable spinal implant <NUM> can include a first height H<NUM> (e.g., as measured from the outer surface of the first endplate <NUM> to the outer surface of the second endplate <NUM>). In the expanded configuration, for example, as illustrated in <FIG>, the expandable spinal implant <NUM> can include a second height, H<NUM>, that is greater than the first height. In some embodiments, the second height can be from about <NUM>% to about <NUM>% greater than the first height. In other embodiments, the second height can be from about <NUM>% to about <NUM>% greater than the first height. In other embodiments, the second height can be from at least about <NUM>% greater than the first height. In some embodiments, the first height can be in the range of from about <NUM> to about <NUM>, and/or the second height can be in the range of from about <NUM> to about <NUM>. In other embodiments, the second height can be from about <NUM> to about <NUM> greater than the first height. In some embodiments, the change in height can be caused by movement of the first and second endplates <NUM>, <NUM> towards and/or away from each other. In these embodiments, the first and second endplates <NUM>, <NUM> can be separated by a first distance when in the collapsed configuration and a second distance when in the expanded configuration, wherein the second distance is greater than the first distance. In some embodiments, the implant <NUM> may be wedge-shaped when in the collapsed and/or expanded configurations. For example, the first end <NUM> may have a height that is different from a height of the second end <NUM>, and/or the first end <NUM> may have a height that is different from a height of the second side <NUM>. Advantageously, this shape can enhance contact between the implant <NUM> and vertebral endplates, thereby encouraging a secure fit within an intervertebral space. Those skilled in the art may appreciate that, in use, the height of the expandable spinal implant <NUM> can be adjusted to accommodate an individual patient's anatomy. Additionally, the expandable spinal implant <NUM> may be inserted into an intervertebral space in the collapsed configuration, which may entail less trauma to surrounding tissue due to its smaller size.

Some embodiments herein are directed to an expandable fusion system that can include an expandable spinal implant as described herein (e.g., expandable spinal implant <NUM> and/or <NUM>) and an inserter <NUM> as illustrated in <FIG>. The inserter <NUM> can be configured to reversibly engage at least a portion of the expandable spinal implant (e.g., the body member <NUM> of the expandable spinal implant <NUM>). In <FIG>, the inserter <NUM> is illustrated as being engaged with expandable spinal implant <NUM>. However, those skilled in the art may appreciate that in other embodiments, the inserter <NUM> may be similarly engaged with spinal implant <NUM>, described further herein.

As illustrated in <FIG>, the inserter <NUM> can include an outer sleeve <NUM>, an inner sleeve <NUM>, and/or a driver <NUM>. The inserter <NUM> can also include a handle member <NUM>. The handle member <NUM> may be rotatably and/or pivotably coupled to the outer sleeve <NUM>. The outer and/or inner sleeves <NUM>, <NUM> can each include a cannula extending longitudinally therethrough between a first (e.g., distal) end and a second (e.g., proximal) end. As illustrated in <FIG>, each cannula can include a first opening at a first (e.g., distal) end <NUM> of the inserter <NUM> and a second opening at a second (e.g., proximal) end <NUM> of the inserter <NUM>. The cannula of the inner sleeve <NUM> may be configured to reversibly receive the driver <NUM> therethrough. The driver <NUM> may be configured to rotate within the cannula of the inner sleeve <NUM>. The cannula of the outer sleeve <NUM> may be configured to reversibly receive the inner sleeve <NUM> therethrough. The inner sleeve <NUM> may be configured to rotate within the outer sleeve <NUM>. When in an assembled configuration, the outer sleeve <NUM>, inner sleeve <NUM>, and driver <NUM> may be coaxial.

As illustrated in <FIG>, the outer sleeve <NUM> can include a first end <NUM> that can be configured to engage the body member of the expandable implant (e.g., body member <NUM>). As illustrated in <FIG>, the first end <NUM> can include at least one countertorque tab <NUM> extending distally therefrom. In some embodiments, the first end <NUM> can include two countertorque tabs <NUM>. Each countertorque tab <NUM> can be configured to engage one of the tool-engagement features of the body member (e.g., tool-engagement feature <NUM>). In use, the countertorque tab(s) <NUM> may reduce, inhibit, and/or prevent relative motion between the inserter <NUM> and the expandable implant <NUM>.

As illustrated in <FIG>, the inner sleeve <NUM> can include a first end <NUM> that can include exterior threading. At least a portion of the first end <NUM> can be configured to be received within the expandable spinal implant. For example, the exterior threads on the inner sleeve <NUM> can be configured to threadably engage the second bore <NUM> of the body member <NUM>. In use, the inner sleeve <NUM> can be configured to couple the inserter <NUM> to the expandable spinal implant.

As illustrated in <FIG>, the driver <NUM> can include a first end <NUM> and a second end <NUM>. The driver <NUM> can include a length that is greater than a length of the outer and/or inner sleeves <NUM>, <NUM>. For example, the first end <NUM> and/or the second end <NUM> can extend outside the inner and/or outer sleeves <NUM>, <NUM>. As illustrated in <FIG>, the first end <NUM> of the driver <NUM> can include an insertion portion <NUM> configured to be received within the body member of the expandable spinal implant. In some embodiments, the insertion portion <NUM> can have a length in the range of from <NUM>% to about <NUM>% of the length of the expandable implant. In other embodiments, the insertion portion <NUM> can have a length in the range of from about <NUM>% to about <NUM>% of the length of the expandable implant. In yet other embodiments, the insertion portion <NUM> can have a length that is equal to at least <NUM>% of a length of the expandable implant. In other embodiments, the insertion portion <NUM> can have a length that is equal to at least <NUM>% of a length of the expandable implant. As illustrated in <FIG>, the insertion portion can include a tip <NUM> that can be configured to engage the actuation screw (e.g., actuation screw <NUM>). In some embodiments, the tip <NUM> can be at least partially received within the tool-engagement feature of the head (e.g., screw head <NUM>).

There are also described (even if they do not form part of the invention) methods of installing the expandable spinal implant <NUM>. Methods can include providing the expandable spinal implant <NUM> in the collapsed configuration as described herein. Methods can also include coupling the expandable spinal implant <NUM> with inserter <NUM>. This step can include inserting the countertorque tab(s) <NUM> of the inserter <NUM> into the tool-engagement feature(s) <NUM> of the body member <NUM>. This step can also include threading the first end <NUM> of the inner sleeve <NUM> of the inserter <NUM> into the second bore <NUM> of the body member <NUM>. Those skilled in the art may appreciate that in other embodiments, the spinal implant <NUM> may be installed without the use of the inserter <NUM>.

The method can also include inserting the expandable spinal implant <NUM> between two adjacent vertebrae. Those skilled in the art may appreciate that the first end <NUM> of the driving member <NUM> may define the leading end of the implant <NUM>. Accordingly, the tapered first end <NUM> may advantageously be used to distract the adjacent vertebrae. As described herein, the expandable spinal implant <NUM> may be inserted anywhere along the spinal column, such as between lumbar, thoracic, and/or cervical vertebrae. In addition, the expandable spinal implant <NUM> may be inserted along any approach, such as transforaminal, posterior, lateral, and/or anterior. In some embodiments, the implant <NUM> may be inserted using minimally invasive methods. In some embodiments, the intervertebral space may be prepared beforehand, for example, by performing a discectomy to remove some or all of the intervertebral disc.

The method can also include expanding the expandable implant <NUM>, for example, by transitioning the implant <NUM> from the collapsed configuration to the expanded configuration. To expand the implant <NUM>, the driving member <NUM> may be moved towards the body member <NUM>, or vice versa. This step can include urging a driver into engagement with the actuation screw <NUM>. In some embodiments, this step can include inserting driver <NUM> through the inner sleeve <NUM> and/or the body member <NUM> and into engagement with the actuation screw <NUM>, as illustrated in <FIG>. In these embodiments, the inner sleeve <NUM> may be coupled with the expandable implant <NUM> prior to engaging the driver <NUM> with the actuation screw <NUM>. For example, as illustrated in <FIG>, the first end <NUM> of the inner sleeve <NUM> may threadably engage the second bore <NUM> of the body member <NUM>.

Once the driver is engaged with the actuation screw <NUM>, the step of expanding the implant <NUM> can also include applying a rotational force to the driver <NUM> to rotate the actuation screw <NUM>. As the actuation screw <NUM> rotates in a first direction, the threaded body <NUM> engages the driving member <NUM>, translating the driving member <NUM> relative to the body member <NUM>. As the body member <NUM> and the driving member <NUM> translate towards each other, the respective mating elements of the body member <NUM> and/or the driving member <NUM> may push against corresponding complementary mating elements on the first and second endplates <NUM>, <NUM>, thereby pushing the first and second endplates <NUM>, <NUM> apart and increasing the height of the implant <NUM>. In other embodiments, as the actuation screw <NUM> is rotated in a second direction, the threaded body <NUM> may push the driving member <NUM> away from the body member <NUM>, or vice versa. Thus, those skilled in the art may appreciate that the implant <NUM> may be reversibly expandable and/or collapsible. Accordingly, some embodiments can include reducing and/or adjusting the height of the implant <NUM>, for example, by bringing the first and second endplates <NUM>, <NUM> together. In some embodiments, the implant <NUM> can include a locking member configured to lock the implant in the collapsed and/or expanded configuration. In these embodiments, the method can also include the step of locking the implant <NUM> at a particular height.

After the expandable implant <NUM> has been expanded, the driver <NUM> may be removed (e.g., may be pulled proximally through the cannula of the inner sleeve <NUM>). Bone graft material may then be inserted into the cavity <NUM> of the body member <NUM>. In some embodiments, the bone graft material may be inserted through the cannula of the inner sleeve <NUM> to the cavity <NUM>. Advantageously, the implant <NUM> may be backfilled with bone graft material in situ, rather than being prepacked prior to insertion. Accordingly, more bone graft material can be inserted, thereby promoting increased fusion. Additionally, the same cannula (e. g, of the inner sleeve <NUM>) may be used to insert the driver <NUM> and the bone graft material. Advantageously, this method may save time and/or materials as compared to other methods that rely on separate instruments for insertion (and/or expansion) of the implant and subsequent insertion of bone graft material.

Turning now to <FIG>, an alternative embodiment of an expandable spinal implant is illustrated. As illustrated in <FIG>, expandable spinal implant <NUM> can include a body member <NUM>, a first (e.g., upper and/or superior) driving unit <NUM>, a second (e.g., lower and/or inferior) driving unit <NUM>, a first (e.g., upper and/or superior) endplate <NUM>, a second (e.g., lower and/or inferior) endplate <NUM>, and an actuator assembly <NUM>. As illustrated in <FIG>, the expandable spinal implant <NUM> can also include a first (e.g., leading and/or distal) end <NUM> and a second (e.g., trailing and/or proximal) end <NUM>. As illustrated in <FIG>, the expandable spinal implant <NUM> can include a first (e.g., anterior) side <NUM> and a second (e.g., posterior) side <NUM>. As described further herein, expandable spinal implant <NUM> can include an adjustable height and/or lordotic angle. In some embodiments, the expandable spinal implant <NUM> may be configured to pivotably expand. As described further herein, the first and/or second endplates <NUM>, <NUM> may be configured to pivot relative to the body member <NUM>. In some embodiments, the expandable spinal implant <NUM> may be part of an expandable fusion system, for example, in combination with the inserter <NUM>.

As illustrated in <FIG>, the body member <NUM> can include a first end <NUM> having a first end section <NUM> and a second end <NUM> having a second end section <NUM>. The body member <NUM> can also include a cavity <NUM> between the first and second end sections <NUM>, <NUM>. In some embodiments, the first end <NUM> may be referred to as the leading and/or distal end. The second end <NUM> may be referred to as the trailing and/or proximal end.

As illustrated in <FIG>, the first end section <NUM> can include a first bore <NUM> and the second end section <NUM> can include a second bore <NUM>. The first and second bores <NUM>, <NUM> can define an elongate channel extending longitudinally through the body member <NUM>. As illustrated in <FIG>, the first and second bores <NUM>, <NUM> can be coaxial along longitudinal axis <NUM> of the body member <NUM>. The first bore <NUM> may be non-threaded (e.g., smooth). In some embodiments, it can include a circumferential groove <NUM>. The first bore <NUM> can have a constant or variable diameter. In some embodiments, the first bore <NUM> can include a first section having a first diameter and a second section having a second diameter that is different than the first diameter. For example, the first bore <NUM> can include a reduced-diameter section <NUM> located at the first end <NUM> of the body member <NUM>. The reduced-diameter section <NUM> may be a distal section of the first bore <NUM>. The second bore <NUM> may be threaded. The second bore <NUM> may be configured to threadably engage an insertion tool as described further herein. The second bore <NUM> may also be configured to receive bone graft material therethrough.

As illustrated in <FIG>, the body member <NUM> can also include a first side wall <NUM> at a first side <NUM> and a second side wall <NUM> at a second side <NUM>. Each of the first and second side walls <NUM>, <NUM> can extend from the first end section <NUM> to the second end section <NUM>. As illustrated in <FIG>, the cavity <NUM> can be defined between and/or bounded by the first end section <NUM>, second end section <NUM>, first side wall <NUM>, and second side wall <NUM>. As illustrated in <FIG>, the second end section <NUM> can also include one or more tool engagement feature(s) <NUM>, such as a notch, cut-out, or groove. Each tool-engagement feature <NUM> may be configured to engage an insertion tool (e.g., outer sleeve <NUM>) as described further herein.

The second end section <NUM> of the body member <NUM> may be configured to engage the first and/or second endplates <NUM>, <NUM>. For example, the second end section <NUM> can include at least one recess, such as a groove, notch, and/or channel, configured to receive at least a portion of the first and/or second endplate <NUM>, <NUM> therein. As illustrated in <FIG>, an upper portion of the second end section <NUM> can include two notches <NUM>, <NUM>, which may be configured to engage the first endplate <NUM>. Those skilled in the art may appreciate that a lower portion of the second end section <NUM> can also include two notches configured to engage the second endplate <NUM>.

As described herein, the first and/or second endplates <NUM>, <NUM> may be configured to pivot relative to the body member <NUM>. In some embodiments, the first and/or second endplates <NUM>, <NUM> may be pivotably, jointedly, and/or hingedly coupled to the body member <NUM>. Accordingly, the body member <NUM> may include one or more hinge elements. Each hinge element may be disposed on the second end section <NUM> of the body member <NUM>. In some embodiments, the hinge element can include a recess, such as a bore, hole, aperture, and/or channel. In other embodiments, the hinge element can include a protrusion, such as a pin, axle, shaft, and/or rod. The hinge element may be rounded and/or curved. In some embodiments, the hinge element can be cylindrical or partially cylindrical. The hinge element can define an axis of rotation. The axis of rotation may be parallel to a horizontal transverse axis <NUM> of the expandable implant <NUM>. As illustrated in <FIG>, the body member <NUM> can include a first hinge element <NUM> and a second hinge element <NUM>. In these embodiments, the first and second hinge elements <NUM>, <NUM> may include, respectively, a first bore and a second bore. In some embodiments, the first hinge element <NUM> may be configured to form a joint with a corresponding hinge element on the first endplate <NUM> and the second hinge element <NUM> may be configured to form a joint with a corresponding hinge element on the second endplate <NUM>. In other embodiments, the first hinge element <NUM> may be configured to engage the first endplate <NUM> and the second hinge element <NUM> may be configured to engage the second endplate <NUM>. The body member <NUM> can include two, four, six, or more hinge elements. In some embodiments, the second end section <NUM> of the body member <NUM> can include a third hinge element <NUM> and a fourth hinge element <NUM>, as illustrated in <FIG>. In some embodiments, the body member <NUM> can include two hinge elements (e.g., first and third hinge elements <NUM>, <NUM>) on the upper portion and two hinge elements (e.g., second and fourth hinge elements <NUM>, <NUM>) on the lower portion thereof. The first and third hinge elements <NUM>, <NUM> may be configured to be coaxial with axis <NUM> of the first endplate <NUM> when in an assembled configuration. The second and fourth hinge elements <NUM>, <NUM> may be configured to be coaxial with a corresponding axis of the second endplate <NUM>. In other embodiments, the body member <NUM> can include two hinge elements (e.g., first and second hinge elements <NUM>, <NUM>) at the first side <NUM> and two hinge elements (e.g., third and fourth hinge elements <NUM>, <NUM>) at the second side <NUM>.

In some embodiments where one or more hinge elements include a bore, the expandable spinal implant <NUM> can also include one or more proximal pivot pins <NUM>, as illustrated in <FIG>. As illustrated in <FIG>, the expandable spinal implant <NUM> can include four pivot pins <NUM>, wherein each pivot pin <NUM> corresponds to each of the hinge elements <NUM>, <NUM>, <NUM>, and <NUM>. Each pivot pin <NUM> can include a curved and/or rounded exterior surface. In some embodiments, each pivot pin <NUM> may be cylindrical. Each pivot pin <NUM> may be configured to be pivotably and/or rotatably received within the respective hinge element <NUM>, <NUM>, <NUM>, and/or <NUM>. Each pivot pin <NUM> may be configured to be coaxial with respect to the respective hinge element <NUM>, <NUM>, <NUM>, and/or <NUM>.

The first end section <NUM> of the body member <NUM> may also be configured to engage the first and/or second endplates <NUM>, <NUM>. For example, the first end section <NUM> can include at least one extension members. As illustrated in <FIG>, the first end section <NUM> can include a first extension member <NUM> at an upper end thereof and configured to engage the first endplate <NUM>. The first end section <NUM> can include a second extension member <NUM> at a lower end thereof and configured to engage the second endplate <NUM>. The extension members <NUM>, <NUM> may each be configured to fit within a corresponding groove on the first and/or second endplates <NUM>, <NUM>, for example, as illustrated in <FIG>.

The first driving unit <NUM> can be configured to engage the first endplate <NUM>. The second driving unit <NUM> can be configured to engage the second endplate <NUM>. In some embodiments, the first and/or second endplates <NUM>, <NUM> may be configured to translate and/or slide relative to the first and/or second driving units <NUM>, <NUM>. When in an assembled configuration, the first and/or second driving units <NUM>, <NUM> can be located distal to the body member <NUM> (e.g., closer to the first end <NUM> than the second end <NUM>), as illustrated in <FIG>. As illustrated in <FIG>, the first driving unit <NUM> can include a first (e.g., leading and/or distal) end <NUM> and a second (e.g., trailing and/or proximal) end <NUM>. The first driving unit <NUM> can also include a first side <NUM> and a second side <NUM>, as illustrated in <FIG>. The first driving unit <NUM> can include a width, as measured from the first side <NUM> to the second side <NUM>, which is generally equal to a width of the body member <NUM>. The first driving unit <NUM> can include a tapered section. The tapered section may be located at the first end <NUM>. The tapered section can include a variable height. For example, as illustrated in <FIG>, at least a portion of the first driving unit <NUM> can have a height that decreases towards the first end <NUM>. As illustrated in <FIG>, the first driving unit <NUM> can include a channel <NUM> extending therethrough along longitudinal axis <NUM>. As illustrated in <FIG>, the channel <NUM> can include a curved opening. As described further herein, the channel <NUM> can be configured to receive at least a portion of the nut <NUM> of the actuator assembly <NUM> therein. In some embodiments, the nut <NUM> may be configured to nest within the channel <NUM>. In other embodiments, the channel <NUM> may include a radius of curvature that is greater than or equal to a radius of curvature of the outer surface of the nut <NUM>. When in an assembled configuration, the first driving unit <NUM> may be configured to pivot about the nut <NUM>.

The first driving unit <NUM> can include one or more mating elements. In some embodiments, the first driving unit <NUM> can include two mating elements. The mating elements may be configured to engage the first endplate <NUM>. As illustrated in <FIG>, the first driving unit <NUM> can include a first mating element <NUM> at the first side <NUM> and a second mating element <NUM> at the second side <NUM>. The mating element(s) may be generally located at the second end <NUM> of the first driving unit <NUM>.

Each mating element of the first driving unit <NUM> can be configured (e.g., shaped) to mate with a corresponding complementary mating element on the first endplate <NUM> as described herein. Each mating element can be ramped (e.g., angled, inclined, and/or declined), and/or can include a ramped member. In some embodiments, one or more mating elements on the first driving unit <NUM> can include a protrusion (e.g., a tongue, rail, and/or shoulder). In other embodiments, one or more mating elements on the first driving unit <NUM> can include a recess (e.g., a groove, track, and/or channel). In some embodiments, one or more mating elements can include an extension member. For example, as illustrated in <FIG>, second mating element <NUM> can include a groove <NUM> and an extension tab <NUM> that can at least partially protrude into the groove <NUM>. Those skilled in the art may appreciate the groove <NUM> may be configured to receive an extension tab of a mating element of the first endplate <NUM> therein. Additionally, the tab <NUM> may provide enhanced engagement with the first endplate <NUM> thereby reducing movement, separation, and/or decoupling between the first endplate <NUM> and first driving unit <NUM> when in use. As illustrated in <FIG>, first mating element <NUM> may include a groove and a tab. In other embodiments, any and/or all mating elements of the first driving unit <NUM> can include a groove and a tab. In yet other embodiments, the mating element can include a protrusion and an engagement receptacle (e.g., a cut-out) that overlaps the protrusion.

Each mating element on the first driving unit <NUM> may include an inclination substantially similar to that of each complementary mating element on the first endplate <NUM>. In some embodiments, each mating element on the first driving unit <NUM> can be inclined longitudinally from the second end <NUM> towards the first end <NUM>, as illustrated in <FIG>. In other embodiments, each mating element on the first driving unit <NUM> may be angled relative to the longitudinal axis <NUM>, e.g., towards the first end <NUM>.

As described herein, the first and second driving units <NUM>, <NUM> may be configured to pivot relative to each other. In some embodiments, the first and second driving units <NUM>, <NUM> may be pivotably, jointedly, and/or hingedly coupled to each other. In other embodiments, the first and/or second driving units <NUM>, <NUM> may be configured to pivot about the nut <NUM> of the actuator assembly <NUM>. Accordingly, the first driving unit <NUM> can include one or more hinge elements. As illustrated in <FIG>, the first driving unit <NUM> can include a first hinge element <NUM> and a second hinge element <NUM>. Each hinge element may extend from an inner side <NUM> of the first driving unit <NUM>, as illustrated in <FIG>. The one or more hinge elements may be located on the first and/or second sides <NUM>, <NUM> of the first driving unit <NUM>. In some embodiments, the hinge element can include a recess, such as a bore, hole, aperture, and/or channel. In other embodiments, the hinge element can include a protrusion, such as a pin, axle, shaft, and/or rod. The hinge element may be rounded and/or curved. In some embodiments, the hinge element can be cylindrical or partially cylindrical. The hinge element can define an axis of rotation <NUM>, as illustrated in <FIG>. The axis of rotation may be parallel to the horizontal transverse axis <NUM> of the expandable implant <NUM>. In some embodiments, all of the hinge elements on the first driving unit <NUM> may be coaxial. As illustrated in <FIG>, the first and second hinge elements <NUM>, <NUM> may include, respectively, a first bore and a second bore. The first and second bores may be coaxial along axis <NUM>. The first and second bores may define a transverse channel <NUM> through the first driving unit <NUM>. The first and second hinge elements <NUM>, <NUM> may be configured to form a joint with corresponding hinge elements on the second driving element <NUM>. As illustrated in <FIG>, the first hinge element <NUM> can be located at the first side <NUM> and the second hinge element <NUM> can be located at the second side <NUM>. In some embodiments, the first hinge element <NUM> may be located directly on the first side <NUM> and the second hinge element <NUM> may be inset from the second side <NUM>, as illustrated in <FIG>. In other embodiments, the first hinge element <NUM> may be inset from the first side <NUM> and the second hinge element <NUM> can be located directly on the second side <NUM>. Those skilled in the art may appreciate that in use, the staggered and/or offset hinge elements can enable the first driving unit <NUM> to nest and/or mesh with the second driving unit <NUM>.

The second driving unit <NUM> may be configured to engage the second endplate <NUM>. In use, the expandable spinal implant <NUM> may be oriented such that the first driving unit <NUM> is the top, upper, and/or superior driving unit and the second driving unit <NUM> is the bottom, lower, and/or inferior driving unit. The second driving unit <NUM> may include some or all of the same features as the first driving unit <NUM>. In some embodiments, the second driving unit <NUM> may be identical to the first driving unit <NUM>. Those skilled in the art may appreciate that the description of the first driving unit <NUM> herein may be applied to the second driving unit <NUM> unless stated otherwise. The second driving unit <NUM> may include one or more mating elements that may be configured to engage one or more complementary mating elements on the second endplate <NUM>. When in an assembled configuration, the mating elements on the second driving unit <NUM> may diverge from the mating elements on the first driving unit <NUM> along a longitudinal axis from a position relatively adjacent to the second end <NUM> of the implant <NUM> to a position relatively adjacent to the first end <NUM> thereof. In other embodiments, each mating element on the second driving unit <NUM> can be declined towards the first end <NUM> of the implant <NUM>.

The second driving unit <NUM> may be configured to pivot relative to the first driving unit <NUM>. As illustrated in <FIG>, the second driving unit <NUM> can include a first hinge element <NUM> and a second hinge element <NUM>. The first and second hinge elements <NUM>, <NUM> may each include a first and second bore, respectively. When in an assembled configuration, the first and second hinge elements <NUM>, <NUM> of the second driving unit <NUM> may be coaxial with the first and second hinge elements <NUM>, <NUM> of the first driving unit <NUM> and/or the axis of rotation <NUM>.

In some embodiments where one or more hinge elements of the first and/or second driving units <NUM>, <NUM> include a bore, the expandable spinal implant <NUM> can also include one or more distal pivot pins. As illustrated in <FIG>, the expandable spinal implant <NUM> can include a first distal pivot pin <NUM> and a second distal pivot pin <NUM>. Each pivot pin <NUM>, <NUM> can include a curved and/or rounded exterior surface. In some embodiments, each pivot pin <NUM>, <NUM> may be cylindrical. Each pivot pin <NUM>, <NUM> may be configured to be pivotably and/or rotatably received within the respective hinge element(s) of the first and/or second driving units <NUM>, <NUM>. For example, the first pivot pin <NUM> may be configured to be pivotably and/or rotatably received within hinge elements <NUM>, <NUM>. The second pivot pin <NUM> may be configured to be pivotably and/or rotatably received within hinge elements <NUM>, <NUM>. Each pivot pin <NUM>, <NUM> may also be configured to be at least partially received within the nut <NUM> of the actuator assembly <NUM>, described further herein. In some embodiments, each pivot pin <NUM>, <NUM> may be pivotably and/or rotatably received within the nut <NUM>. In some embodiments, the pivot pins <NUM>, <NUM> may couple the first and second driving units <NUM>, <NUM> with the nut <NUM>.

The first and/or second endplates <NUM>, <NUM> may be configured to engage the body member <NUM>. The first endplate <NUM> may be configured to engage the first driving unit <NUM> and the second endplate <NUM> may be configured to engage the second driving unit <NUM>. In use, the expandable implant <NUM> may be oriented such that the first endplate <NUM> is the top, superior, and/or upper endplate and the second endplate <NUM> is the bottom, inferior, and/or lower endplate. First endplate <NUM> and second endplate <NUM> may include some or all of the same features. Those skilled in the art may appreciate that the description of the first endplate <NUM> herein may be applied to the second endplate <NUM> unless stated otherwise. For example, any description of the relationship between the first endplate <NUM> and the first driving unit <NUM> may be applied to the second endplate <NUM> and the second driving unit <NUM>.

First endplate <NUM> can be configured to pivot relative to the body member <NUM>. In some embodiments, the first endplate <NUM> can be configured to form a joint with the body member <NUM>. First endplate <NUM> may also be configured to slideably engage the first driving unit <NUM>. As illustrated in <FIG>, the first endplate <NUM> can include a first (e.g., leading and/or distal) end <NUM>, a second (e.g., trailing and/or proximal) end <NUM>, a first side <NUM>, and a second side <NUM>. The first endplate <NUM> can include a length between the first and second ends <NUM>, <NUM> and a width between the first and second sides <NUM>, <NUM>. The first endplate <NUM> can include a third (e.g., outer) side <NUM>, illustrated in <FIG>, and a fourth (e.g., inner) side <NUM>, illustrated in <FIG>. As illustrated in <FIG>, the first endplate <NUM> can also include a through-hole <NUM> that passes from the outer side <NUM> to the inner side <NUM>. The through-hole <NUM> can be configured to enable bone graft material deposited within the expandable implant <NUM> to engage, contact, and/or fuse with an adjacent vertebral body. As illustrated in <FIG>, the first endplate <NUM> can include a cut-out or groove <NUM>, which may be in fluid communication with the through-hole <NUM>. The groove <NUM> may be configured to receive a portion of the body member <NUM> therein (e.g., extension member <NUM>), as illustrated in <FIG>. The outer side <NUM> may be configured to engage a vertebral body. The outer side <NUM> may be referred to as an outer surface and/or a superior surface. In some embodiments, the outer side <NUM> can include a plurality of protrusions (e.g., bumps, teeth, and/or peaks) configured to retain the implant <NUM> within an intervertebral space. The outer side <NUM> can be generally planar, concave, and/or convex.

In some embodiments, inner side <NUM> can include at least one wall segment extending therefrom. Each wall segment may extend partially or completely along the length of the first endplate <NUM>. As illustrated in <FIG>, the first side <NUM> can include at least one wall segment and the second side <NUM> can include at least one wall segment. In some embodiments, the first side and/or the second side can include a plurality of overlapping and/or staggered wall segments. The wall segments may be staggered along the length and/or the width of the first endplate <NUM>. In some embodiments, the wall segments may be separated by a gap. For example, as illustrated in <FIG>, the first side <NUM> can include an outer wall segment <NUM> and an inner wall segment <NUM>. The overlapping and/or staggered wall segments can advantageously enable the first and second endplates <NUM>, <NUM> to overlap, thereby reducing the height of the expandable implant <NUM> when in a collapsed configuration, for example, as illustrated in <FIG>.

The first endplate <NUM> can include one or more mating elements. The one or more mating elements may be located at the first end <NUM>. In some embodiments, one or more mating elements of the first endplate <NUM> can include a protrusion (e.g., a tongue, rail, and/or shoulder). In other embodiments, one or more mating elements of the first endplate <NUM> can include a recess (e.g., a groove, track, and/or channel). In some embodiments, at least one mating element can include an extension member. For example, at least one of the mating elements can a groove and an extension tab that can at least partially protrude into the groove. As another example, the mating element can include a protrusion and an engagement receptacle that overlaps the protrusion. The mating elements on the first endplate <NUM> can be configured to form a slidable joint with a complementary mating element on the first driving unit <NUM>. Accordingly, the first driving unit <NUM> may be configured to slideably engage the first endplate <NUM>. The slideable joint may advantageously enable the expandable implant <NUM> to transition reversibly between expanded and contracted configurations. The slidable joint may include, for example, a tabled splice joint, a dovetail joint, a tongue and groove joint, or another suitable joint. In some embodiments, one or more mating elements on the first endplate <NUM> can include a recess (e.g., a groove, track, and/or channel), and one or more mating elements on the first driving unit <NUM> can include a protrusion (e.g., a tongue, rail, and/or shoulder) configured to slide within the groove. In other embodiments, one or more mating elements on the first endplate <NUM> can include a protrusion and one or more mating elements on the first driving unit <NUM> can include a recess.

In some embodiments, the mating elements may be located on and/or extend from the inner side <NUM>. In some embodiments, at least one mating element may be located on a wall segment. In other embodiments, the first side <NUM> can include at least one mating element and the second side <NUM> can include at least one mating element. As illustrated in <FIG>, the first endplate <NUM> can include a first mating element <NUM> and a second mating element <NUM>. The first mating element <NUM> may be located at the first side <NUM> and the second mating element <NUM> may be located at the second side <NUM>. The first and second mating elements <NUM>, <NUM> may each be configured to engage a complementary mating element on the first driving unit <NUM>. Those skilled in the art may appreciate that first and second mating elements on the second endplate <NUM> may each be configured to engage a complementary mating element on the second driving unit <NUM>. Accordingly, each mating element can be ramped (e.g., angled, inclined, and/or declined), and/or can include a ramped member. The mating elements on the first endplate <NUM> may have substantially similar inclinations, when in an assembled configuration, as their complementary mating elements on the first driving unit <NUM>. As illustrated in <FIG>, the first and second mating elements <NUM>, <NUM> may be angled (e.g., inclined or declined) away from the outer side <NUM> in a direction from the first end <NUM> towards the second end <NUM>. For example, the first and/or second mating elements <NUM>, <NUM> may be inclined longitudinally in a direction from the second end <NUM> towards the first end <NUM>.

The first and/or second endplate <NUM>, <NUM> may be configured to be pivotably coupled to the second end section <NUM> of the body member <NUM>. In some embodiments, the first endplate <NUM> may be configured to pivot about a first pivot point (e.g., axis <NUM>, described herein), and the second endplate <NUM> may be configured to pivot about a second pivot point (e.g., axis <NUM>, described herein) that is different from the first pivot point. The first endplate <NUM> can include one or more hinge elements. The one or more hinge elements may be located at the second end <NUM>. In some embodiments, the first endplate <NUM> can include at least one hinge element at the first side <NUM> and at least one hinge element at the second side <NUM>. As described herein, the hinge element(s) may be configured to enable the first and/or second endplates <NUM>, <NUM> to pivot relative to the body member <NUM>. In some embodiments, the hinge element can include a recess, such as a bore, hole, aperture, and/or channel. In other embodiments, the hinge element can include a protrusion, such as a pin, axle, shaft, and/or rod. The hinge element may be rounded and/or curved. In some embodiments, the hinge element can be cylindrical or partially cylindrical. As illustrated in <FIG>, the hinge element can define an axis of rotation <NUM>. The axis of rotation <NUM> may be parallel to the horizontal transverse axis <NUM> of the expandable implant <NUM>, described herein with respect to the body member <NUM>. As illustrated in <FIG>, the first endplate <NUM> can include a first hinge element <NUM> and a second hinge element <NUM>. In these embodiments, the first and second hinge elements <NUM>, <NUM> may include, respectively, a first bore and a second bore. The first and second hinge elements <NUM>, <NUM> (e.g., the first and second bores) may be coaxial with the axis <NUM>. In some embodiments, the first and second hinge elements <NUM>, <NUM> may be configured to form a joint with corresponding hinge elements on the body member <NUM> (e.g., first and third hinge elements <NUM>, <NUM>). The hinge elements <NUM>, <NUM>, <NUM>, and <NUM> may be configured to be coaxial when the implant <NUM> is in an assembled configuration. Those skilled in the art may appreciate that the second endplate <NUM> can include first and second hinge elements configured to form a joint with corresponding hinge elements on the body member <NUM> (e.g., second and fourth hinge elements <NUM>, <NUM>). The hinge elements of the second endplate <NUM> and the hinge elements <NUM>, <NUM> may be configured to be coaxial when the implant <NUM> is in an assembled configuration. Additionally, those skilled in the art may appreciate that when a hinge element includes a bore, the bore may be configured to pivotably and/or rotatably receive proximal pivot pin <NUM> therein.

As illustrated in <FIG>, the actuator assembly <NUM> can include a nut <NUM> and an actuation screw <NUM>. In some embodiments, the actuator assembly <NUM> can also include a snap ring (not shown) and/or a washer (not shown). The nut <NUM> can be configured to be received at least partially within the first driving unit <NUM> and/or the second driving unit <NUM>. For example, the nut <NUM> may be configured to be at least partially received within the channel <NUM> of the first driving unit <NUM> and/or a channel of the second driving unit <NUM>. As illustrated in <FIG>, the nut <NUM> can include a generally curved and/or cylindrical outer surface. The outer surface may have a radius of curvature that is less than or equal to the radius of curvature of the channel(s). As illustrated in <FIG>, the nut <NUM> can include a first (e.g., leading and/or distal) end <NUM> and a second (e.g., trailing and/or proximal) end <NUM>. The first end <NUM> can be tapered. As illustrated in <FIG>, the nut <NUM> can include a longitudinal bore <NUM> that extends along a longitudinal axis <NUM>. The bore <NUM> may be internally-threaded. The nut <NUM> may also include a transverse bore <NUM> that extends along transverse axis <NUM>, as illustrated in <FIG>. The transverse bore <NUM> may be in fluid communication with the longitudinal bore <NUM>. In some embodiments, the transverse bore <NUM> can be perpendicular to the longitudinal bore <NUM>. The transverse bore <NUM> may be non-threaded (e.g., smooth). In some embodiments, the transverse bore <NUM> can extend entirely through the nut <NUM>. As illustrated in <FIG>, the transverse bore <NUM> can include a first opening <NUM> and a second opening <NUM>. In other embodiments, the nut <NUM> can include two transverse bores and/or depressions extending partially therethrough. When in an assembled configuration, the transverse bore <NUM> may be configured to be coaxial with one or more hinge elements of the first and second driving units <NUM>, <NUM>. The transverse bore <NUM> may be configured to receive at least a portion of the distal pivot pins <NUM>, <NUM> therein. For example, the transverse bore <NUM> may have a diameter that is greater than or equal to a diameter of the pivot pins <NUM>, <NUM>. In some embodiments, the pivot pin <NUM> may be received through the first opening <NUM> and the pivot pin <NUM> may be received through the second opening <NUM>.

As illustrated in <FIG>, the actuation screw <NUM> can include a head <NUM> and a threaded body <NUM>. The head <NUM> can be configured to be completely contained between the first and second endplates <NUM>, <NUM> when the expandable spinal implant <NUM> is in an assembled configuration. The head <NUM> may be configured to engage the first end section <NUM> of the body member <NUM>. For example, the head <NUM> can be configured to be received within the first bore <NUM> of the body member <NUM>. In some embodiments, the head <NUM> can include a diameter that is greater than a diameter of the reduced-diameter section <NUM> of the first bore. The threaded body <NUM> can include an outer diameter that is less than the diameter of the reduced-diameter section <NUM>. The threaded body <NUM> can be configured to engage the nut <NUM>. For example, the threaded body <NUM> may be configured to threadably engage the longitudinal bore <NUM> of the nut <NUM>. The head <NUM> can include a tool-engagement feature, such as a recess or socket. The tool-engagement feature may be configured to engage a driver as described herein.

As illustrated in <FIG>, the head <NUM> can include a circumferential groove <NUM>. The circumferential groove <NUM> can be configured to receive the snap ring therein. The circumferential groove <NUM> of the actuation screw <NUM> may be longitudinally aligned with the circumferential groove <NUM> of the body member <NUM>. Accordingly, both circumferential grooves <NUM>, <NUM> may be configured to receive at least a portion of the snap ring therein. Those skilled in the art may appreciate that in use, the snap ring may advantageously retain the actuation screw <NUM> within the body member <NUM>. The washer may have an outer diameter generally less than or equal to the diameter of the first bore <NUM>, and may have an inner diameter generally greater than or equal to the diameter of the reduced-diameter section <NUM> of the first bore <NUM>. The washer may be configured to receive the threaded body <NUM> of the actuation screw <NUM> therethrough. The washer may be configured to be received within the first bore <NUM> of the body member <NUM>. In use, the washer may be positioned between the head <NUM> of the actuation screw <NUM> and the body member <NUM>, and may advantageously provide a bearing surface for the actuation screw <NUM>.

In use, the expandable spinal implant <NUM> may advantageously be configured to reversibly transition between a collapsed configuration and an expanded configuration. The height and/or lordotic angle of the spinal implant <NUM> may vary between the collapsed and expanded configurations. In the collapsed configuration, for example, as illustrated in <FIG>, the expandable spinal implant <NUM> can include a first height H<NUM> (e.g., measured as the greatest distance between the outer surface <NUM> of the first endplate <NUM> and an outer surface <NUM> of the second endplate <NUM>). In these embodiments, the implant <NUM> may be wedge-shaped when viewed from a first and/or second side <NUM>, <NUM> (e.g., as illustrated in <FIG>). For example, the first end <NUM> may be taller than the second end <NUM>, or vice versa. In other embodiments, the first and second endplates <NUM>, <NUM> may be generally parallel when in the collapsed configuration. In these embodiments, the height of the implant <NUM> at the first and second ends <NUM>, <NUM> may be generally equal. In yet other embodiments, the implant <NUM> may be wedge-shaped when viewed from the first and/or second end <NUM>, <NUM>, as illustrated in <FIG>. For example, the second side <NUM> may be taller than the first side <NUM>, or vice versa.

In the expanded configuration, for example, as illustrated in <FIG>, the expandable spinal implant <NUM> can include a second height, H<NUM>, that is greater than the first height. In some embodiments, the second height can be from about <NUM>% to about <NUM>% greater than the first height. In other embodiments, the second height can be from about <NUM>% to about <NUM>% greater than the first height. In some embodiments, the first height can be in the range of from about <NUM> to about <NUM>, and/or the second height can be in the range of from about <NUM> to about <NUM>. The change in height can be caused by movement of the first and second endplates <NUM>, <NUM> towards and/or away from each other and/or the body member <NUM>. As described herein, the first endplate <NUM> may be configured to pivot relative to the body member <NUM> about axis <NUM>. The second endplate <NUM> may be configured to pivot relative to the body member <NUM> about axis <NUM>, illustrated in <FIG>. Accordingly, the first ends <NUM>, <NUM> of the first and second endplates <NUM>, <NUM> may be pivoted towards and/or away from each other and/or the body member <NUM>. In some embodiments, the first ends <NUM>, <NUM> of the first and second endplates <NUM>, <NUM> can be separated by a first distance when in the collapsed configuration and a second distance when in the expanded configuration, wherein the second distance is greater than the first distance. When in an expanded configuration, the expandable spinal implant <NUM> may be wedge-shaped when viewed from the first and/or second side <NUM>, <NUM>, as illustrated in <FIG>, and/or when viewed from the first and/or second end <NUM>, <NUM>, as illustrated in <FIG>. Advantageously, this shape can enhance contact between the implant <NUM> and vertebral endplates, thereby encouraging a secure fit within an intervertebral space.

In some embodiments, the first and second endplates <NUM>, <NUM> can define a first angle along a longitudinal axis <NUM> when in the collapsed configuration. In other embodiments, the first and second endplates <NUM>, <NUM> may be generally parallel to each other when in the collapsed configuration. As illustrated in <FIG>, the first and second endplates <NUM>, <NUM> can define a second angle β along the longitudinal axis <NUM>, when in the expanded configuration. The first and/or second endplates <NUM>, <NUM> can pivot apart about the respective axes <NUM>, <NUM> to expand the implant <NUM> and orient the first and second endplates <NUM>, <NUM> at the second angle β. The second angle β may thus be greater than the first angle. In some embodiments, the first (e.g., collapsed) angle can be in the range of from about <NUM>° to about <NUM>°. In other embodiments, the first angle may be in the range of from about <NUM>° to about <NUM>°. In some embodiments, the second (e.g., expanded) angle β can be in the range of from about <NUM>° to about <NUM>°. In other embodiments, the second angle β may be in the range of from about <NUM>° to about <NUM>°. In some embodiments, the implant <NUM> may be expanded by both the linear and pivotal movement of the first and/or second endplates <NUM>, <NUM>. Those skilled in the art may appreciate that, in use, the height and/or lordotic angle of the expandable spinal implant <NUM> can advantageously be adjusted to accommodate an individual patient's anatomy. Additionally, the expandable spinal implant <NUM> may be inserted into an intervertebral space in the collapsed configuration, which may entail less trauma to surrounding tissue due to its smaller size.

Are also here disclosed but do not form part of the invention methods of installing the expandable spinal implant <NUM>. Methods can include providing the expandable spinal implant <NUM> in the collapsed configuration as described herein. Methods can also include coupling the expandable spinal implant <NUM> with inserter <NUM>. This step can include inserting the countertorque tab(s) <NUM> of the inserter <NUM> into the tool-engagement feature(s) <NUM> of the body member <NUM>. This step can also include threading the first end <NUM> of the inner sleeve <NUM> of the inserter <NUM> into the second bore <NUM> of the body member <NUM>. Those skilled in the art may appreciate that in other embodiments, the spinal implant <NUM> may be installed without the use of the inserter <NUM>.

The method can also include inserting the expandable spinal implant <NUM> between two adjacent vertebrae. Those skilled in the art may appreciate that the first ends of the first and second driving units <NUM>, <NUM> may define the leading end of the implant <NUM>. Accordingly, the tapered first end of the first and second driving units <NUM>, <NUM> may advantageously be used to distract the adjacent vertebrae. As described herein, the expandable spinal implant <NUM> may be inserted anywhere along the spinal column, such as between lumbar, thoracic, and/or cervical vertebrae. In addition, the expandable spinal implant <NUM> may be inserted along any approach, such as transforaminal, posterior, lateral, and/or anterior. In some embodiments, the implant <NUM> may be inserted using minimally invasive methods. In some embodiments, the intervertebral space may be prepared beforehand, for example, by performing a discectomy to remove some or all of the intervertebral disc.

The method can also include expanding the expandable implant <NUM>, for example, by transitioning the implant <NUM> from the collapsed configuration to the expanded configuration. To expand the implant <NUM>, the first and second driving units <NUM>, <NUM> may be moved towards the body member <NUM>, or vice versa, as illustrated in <FIG>. This step can include urging a driver into engagement with the actuation screw <NUM>. In some embodiments, this step can include inserting driver <NUM> through the inner sleeve <NUM> and/or the body member <NUM> and into engagement with the actuation screw <NUM>. In these embodiments, the inner sleeve <NUM> may be coupled with the expandable implant <NUM> prior to engaging the driver <NUM> with the actuation screw <NUM>. For example, the first end <NUM> of the inner sleeve <NUM> may threadably engage the second bore <NUM> of the body member <NUM>.

Once the driver is engaged with the actuation screw <NUM>, the step of expanding the implant <NUM> can also include applying a rotational force to the driver <NUM> to rotate the actuation screw <NUM>. As the actuation screw <NUM> rotates in a first direction, the threaded body <NUM> engages the nut <NUM>, translating the nut <NUM> relative to the body member <NUM>. The proximal pivot pins <NUM>, <NUM> may pivotably couple the nut <NUM>, first driving unit <NUM>, and second driving unit <NUM>. Thus, as the nut <NUM> translates, it may urge the first and/or second driving units <NUM>, <NUM> to translate and/or pivot. As the body member <NUM> and the driving units <NUM>, <NUM> translate towards each other and/or pivot, the respective mating elements of the driving units <NUM>, <NUM> may push against complementary mating elements on the first and second endplates <NUM>, <NUM> thereby pushing the first ends <NUM>, <NUM> of the first and second endplates <NUM>, <NUM> apart and increasing the height of the implant <NUM>. Because the second ends of the first and second endplates <NUM>, <NUM> may be pivotably coupled to the body member <NUM>, the first ends <NUM>, <NUM> may pivot apart, thereby increasing and/or changing the angle between (e.g., defined by) the first and second endplates <NUM>, <NUM>. In other embodiments, as the actuation screw <NUM> is rotated in a second direction, the threaded body <NUM> may push the first and second driving units <NUM>, <NUM> away from the body member <NUM>, or vice versa. Thus, those skilled in the art may appreciate that the implant <NUM> may be reversibly expandable and/or collapsible. Accordingly, some embodiments can include reducing and/or adjusting the height of the implant <NUM>, for example, by bringing the first and second endplates <NUM>, <NUM> together. In some embodiments, the implant <NUM> can include a locking member configured to lock the implant in the collapsed and/or expanded configuration. In these embodiments, the method can also include the step of locking the implant <NUM> at a particular height.

In some embodiments, any of the implants and instruments described above can be used with additional implants and instruments. In some embodiments, the implants and instruments can be used with stabilization members, such as plates, screws, and rods. In addition, a multi-level construct can be formed, wherein any one of the implants described above can be used on one level, while a similar or different implant (e.g., fusion or prosthetic) can be used on a different level.

Claim 1:
An expandable fusion system (<NUM>) comprising an expandable spinal implant (<NUM>) having a proximal end and a distal end, comprising:
a body member (<NUM>) comprising a first end section (<NUM>), a second end section (<NUM>), and a cavity (<NUM>) therebetween, the first end section (<NUM>) comprising a first bore (<NUM>) and the second end section (<NUM>) comprising a second bore (<NUM>);
a driving member (<NUM>) comprising a tapered section at the distal end and disposed distal to the body member (<NUM>) the driving member (<NUM>) having a threaded bore (<NUM>);
the driving member (<NUM>) being movable towards to and away from the body member (<NUM>)
a first endplate (<NUM>) configured to engage the body member (<NUM>) and the driving member (<NUM>);
a second endplate (<NUM>) configured to engage the body member (<NUM>) and the driving member (<NUM>); and
an actuator assembly (<NUM>) comprising an actuation screw (<NUM>), the actuation screw (<NUM>) comprising a head (<NUM>) and a threaded body (<NUM>) threadably received in the threaded bore (<NUM>) of the driving member (<NUM>), wherein the head (<NUM>) is configured to be completely contained between the first endplate (<NUM>) and the second endplate (<NUM>) and wherein the rotation screw is so configured that the rotation of the actuation screw (<NUM>) in a first direction (<NUM>) causes the threaded body (<NUM>) to engage with the driving member (<NUM>) translating the driving member (<NUM>) relative to the body member (<NUM>) so that the respective mating elements of the body member (<NUM>) and/or the driving member (<NUM>) push against corresponding complementary mating elements on the first and second endplates (<NUM>, <NUM>), thereby pushing the first and second endplates (<NUM>, <NUM>) apart and increasing the height of the implant (<NUM>).