Patent Description:
A variety of different implants are used in the body. Implants used in the body to stabilize an area and promote bone ingrowth provide both stability (i.e. minimal deformation under pressure over time) and space for bone ingrowth.

Spinal fusion, also known as spondylodesis or spondylosyndesis, is a surgical treatment method used for the treatment of various morbidities such as degenerative disc disease, spondylolisthesis (slippage of a vertebra), spinal stenosis, scoliosis, fracture, infection or tumor. The aim of the spinal fusion procedure is to reduce instability and thus pain.

In preparation for the spinal fusion, most of the intervertebral disc is removed. An implant, the spinal fusion cage, may be placed between the vertebra to maintain spine alignment and disc height. The fusion (i.e. bone bridge) occurs between the endplates of the vertebrae.

The present invention relates to a implant device as claimed hereafter. Preferred embodiments of the invention are set forth in the dependent claims. According to the invention, an implant includes a body with a longitudinal axis. The implant also includes a blade having a retracted position in the body and an extended position where the blade extends outwardly from the body. The implant also includes a blade actuating member that can translate through the body in directions parallel to the first axis. The blade actuating member includes a channel, where the channel extends between a superior surface and an inferior surface of the blade actuating member, and where the channel defines a first channel direction and an opposing second channel direction. The blade includes a protruding portion configured to fit within the channel. When the blade actuating member is moved in a first direction along the first axis, the protruding portion follows the channel in the first channel direction and the blade moves towards the extended position. When the blade actuating member is moved in a second direction opposite the first direction, the protruding portion follows the channel in the second channel direction and the blade moves towards the retracted position. The blade has an outer edge, an inner edge disposed opposite the outer edge, a first lateral edge, and a second lateral edge disposed opposite the first lateral edge. According to the invention, the blade is only in contact with the body along the first lateral edge and the second lateral edge.

In another embodiment, an implant includes a body having a first axis. The implant also includes a blade having a retracted position in the body and an extended position where the blade extends outwardly from the body. The blade has an outer edge, an inner edge, a first lateral edge and a second lateral edge. The first lateral edge of the blade and the second lateral edge of the blade are in contact with the body. The blade also has a distal face and a proximal face. The implant includes a blade actuating member that can translate through the body in directions parallel to the first axis. A portion of the proximal face is in contact with the blade actuating member. The distal face is disposed away from the body. The blade actuating member can move the blade between the retracted position and the extended position.

In another embodiment, an implant includes an outer structure having a first axis. The implant also includes a blade having a retracted position in the outer structure and an extended position where the blade extends outwardly from the outer structure. The implant also includes a blade actuating member that can translate through the outer structure in directions parallel to the first axis. The blade actuating member is coupled to the blade and can move the blade between the retracted position and the extended position. The outer structure includes a first end having a threaded opening and a guide opening adjacent the threaded opening, where the guide opening receives a driven end of the blade actuating member. The implant also includes a locking screw secured within the threaded opening. The locking screw can be rotated between an unlocked rotational position in which the driven end of the blade actuating member can pass through the guide opening and a locked rotational position, in which the drive end of the blade actuating member is prevented from moving through the guide opening.

Other systems, methods (not claimed), features and advantages of the embodiments will be, or will become, apparent to one of ordinary skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods (not claimed), features and advantages be included within this description and this summary, be within the scope of the embodiments, and be protected by the following claims.

The components in the figures are not necessarily to scale, with emphasis instead being placed upon illustrating the principles of the embodiments.

The embodiments described herein are directed to an implant for use in a spine. The embodiments include implants with a body and one or more blades. In addition to the various provisions discussed below, any embodiments may make use of any of the body/support structures, blades, actuating members or other structures disclosed in <CIT>, currently <CIT> and titled "Interbody Fusion Device and System for Implantation". For purposes of convenience, the Duffield patent will be referred to throughout the application as "The Fusion Device Application".

<FIG> is a schematic view of an embodiment of an implant <NUM>. Implant <NUM> may also be referred to as a cage or fusion device. In some embodiments, implant <NUM> is configured to be implanted within a portion of the human body. In some embodiments, implant <NUM> may be configured for implantation into the spine. In some embodiments, implant <NUM> may be a spinal fusion implant, or spinal fusion device, which is inserted between adjacent vertebrae to provide support and/or facilitate fusion between the vertebrae. For example, referring to <FIG>, implant <NUM> has been positioned between a first vertebra <NUM> and a second vertebra <NUM>. Moreover, implant <NUM> is seen to include two blades (first blade <NUM> and second blade <NUM>), which extend from the superior and inferior surfaces of implant <NUM>. Each of the blades has been driven into an adjacent vertebra (i.e., first vertebra <NUM> or second vertebra <NUM>) so as to help anchor implant <NUM>.

In some embodiments, implant <NUM> may be inserted using a lateral interbody fusion (LIF) surgical procedure. In some cases, implant <NUM> could be inserted through a small incision in the side of the body. Exemplary techniques that could be used include, but are not limited to: DLIF® (Direct Lateral interbody Fusion), XLIF® (eXtreme Lateral interbody Fusion), and transpsoas interbody fusion.

For purposes of clarity, reference is made to various directional adjectives throughout the detailed description and in the claims. As used herein, the term "anterior" refers to a side or portion of an implant that is intended to be oriented towards the front of the human body when the implant has been placed in the body. Likewise, the term "posterior" refers to a side or portion of an implant that is intended to be oriented towards the back of the human body following implantation. In addition, the term "superior" refers to a side or portion of an implant that is intended to be oriented towards a top (e.g., the head) of the body while "inferior" refers to a side or portion of an implant that is intended to be oriented towards a bottom of the body. Reference is also made herein to "lateral" sides or portions of an implant, which are sides or portions facing along a lateral direction of the body.

<FIG> is a schematic isometric view of an embodiment of implant <NUM>, according to an embodiment. As seen in <FIG>, implant <NUM> is understood to be configured with an anterior side <NUM> and a posterior side <NUM>. Implant <NUM> may also include a first lateral side <NUM> and a second lateral side <NUM>. Furthermore, implant <NUM> may also include a superior side <NUM> and an inferior side <NUM>.

Reference is also made to directions or axes that are relative to the implant itself, rather than to its intended orientation with regards to the body. For example, the term "distal" refers to a part that is located further from a center of an implant, while the term "proximal" refers to a part that is located closer to the center of the implant. As used herein, the "center of the implant" could be the center of mass and/or a central plane and/or another centrally located reference surface.

An implant may also be associated with various axes. Referring to <FIG>, implant <NUM> may be associated with a longitudinal axis <NUM> that extends along the longest dimension of implant <NUM> between first lateral side <NUM> and second lateral side <NUM>. Additionally, implant <NUM> may be associated with a posterior-anterior axis <NUM> (also referred to as a "widthwise axis") that extends along the widthwise dimension of implant <NUM>, between posterior side <NUM> and anterior side <NUM>. Moreover, implant <NUM> may be associated with a vertical axis <NUM> that extends along the thickness dimension of implant <NUM> and which is generally perpendicular to both longitudinal axis <NUM> and posterior-anterior axis <NUM>.

An implant may also be associated with various reference planes or surfaces. As used herein, the term "median plane" refers to a vertical plane which passes from the anterior side to the posterior side of the implant, dividing the implant into right and left halves, or lateral halves. As used herein, the term "transverse plane" refers to a horizontal plane located in the center of the implant that divides the implant into superior and inferior halves. As used herein, the term "coronal plane" refers to a vertical plane located in the center of the implant that divides the implant into anterior and posterior halves. In some embodiments, the implant is symmetric about two planes, such as the median and the transverse plane.

<FIG> is a schematic isometric exploded view of implant <NUM> according to an embodiment. Referring first to <FIG>, implant <NUM> is comprised of a body <NUM> and a cap <NUM>, which together may be referred to as outer structure <NUM> of implant <NUM>. In some embodiments, a body and cap may be integrally formed. In other embodiments, a body and cap may be separate pieces that are joined by one or more fasteners. In the embodiment of <FIG>, body <NUM> and cap <NUM> are separate pieces that are fastened together using additional components of implant <NUM>.

Embodiments of an implant may include provisions for anchoring the implant into adjacent vertebral bodies. In some embodiments, an implant may include one or more anchoring members. In the embodiment of <FIG>, implant <NUM> includes a set of blades <NUM> that facilitate anchoring implant <NUM> to adjacent vertebral bodies following insertion of implant <NUM> between the vertebra; bodies. Set of blades <NUM> may be further comprised of a first blade <NUM> and a second blade <NUM>. Although the exemplary embodiments described herein include two blades, other embodiments of an implant could include any other number of blades. For example, in another embodiment, three blades could be used. In another embodiment, four blades could be used, with two blades extending from the inferior surface and two blades extending from the superior surface of the implant. Still other embodiments could include five or more blades. In yet another embodiment, a single blade could be used.

An implant with blades can include provisions for moving the blades with respect to an outer structure of the implant. In some embodiments, an implant includes a blade actuating member that engages with one or more blades to extend and/or retract the blades from the surfaces of the implant. In the embodiment shown in <FIG>, implant <NUM> includes a blade actuating member <NUM>. In some embodiments, blade actuating member <NUM> is coupled to first blade <NUM> and second blade <NUM>. Moreover, by adjusting the position of blade actuating member <NUM> within outer structure <NUM>, first blade <NUM> and second blade <NUM> can be retracted into, or extended from, surfaces of implant <NUM>.

An implant can include provisions for locking the position of one or more elements of the implant. In embodiments where the position of a blade actuating member can be changed, an implant can include provisions for locking the actuating member in a given position, thereby also locking one or more blades in a given position. In the embodiment shown in <FIG>, implant <NUM> includes locking screw <NUM>. In some embodiments, locking screw <NUM> can be used to lock blade actuating member <NUM> in place within implant <NUM>, which ensures first blade <NUM> and second blade <NUM> remain in an extended position.

Embodiments can include one or more fasteners that help attach a body to a cap. In some embodiments, pins, screws, nails, bolts, clips, or any other kinds of fasteners could be used. In the embodiment shown in <FIG>, implant <NUM> includes a set of pins <NUM> that help fasten cap <NUM> to body <NUM>. In the exemplary embodiments, two pins are used, including first pin <NUM> and second pin <NUM>. In other embodiments, however, any other number of pins could be used. In another embodiment, a single pin could be used. In still other embodiments, three or more pins could be used.

The embodiments described herein provide an implant that can move from a first position (the "insertion position"), which allows the implant to maintain a low profile, to a second position (the "impaction position" or the "deployed position"), that deploys the blades and inserts them into the proximal superior and inferior vertebral bodies. While the implant is in the first (insertion) position, the blades of the device may be retracted within the body of the implant (i.e., the blades may themselves be in a "retracted position"). In the second (deployed) position of the implant, the blades extend superiorly (or cranially) or inferiorly (or caudally) beyond the implant and into the vertebral bodies to prevent the implant from moving out of position over time. Thus, the blades themselves may be said to be in an "extended position" or "deployed position". When the blades are deployed, the implant resists left to right rotation and resists flexion and/or extension. It may be appreciated that although the blades may approximately move in vertical directions (i.e., the superior and inferior directions), the actual direction of travel may vary from one embodiment to another. For example, in some embodiments the blades may be slightly angled within the implant and may deploy at slight angles to a vertical direction (or to the inferior/superior directions).

<FIG> illustrate several views of implant <NUM> in different operating modes or operating positions. Specifically, <FIG> is a schematic isometric view of implant <NUM> in an insertion position. <FIG> is a schematic lateral side view of implant <NUM> in the same insertion position of <FIG>. Referring to <FIG>, in the insertion position driven end <NUM> of blade actuating member <NUM> may be disposed distal to guide opening <NUM> of cap <NUM> (i.e., a portion of blade actuating member <NUM> is disposed through guide opening <NUM>). With implant <NUM> in the insertion position, first blade <NUM> and second blade <NUM> are retracted within outer structure <NUM>. Thus, as best seen in <FIG>, neither first blade <NUM> or second blade <NUM> extend outwardly (distally) from superior side <NUM> or inferior side <NUM>, respectively, of implant <NUM>. In this insertion position, implant <NUM> has a compact profile and can be more easily maneuvered into place in the excised disc space between adjacent vertebrae.

<FIG> is a schematic isometric view of implant <NUM> in a deployed position. <FIG> is a schematic lateral side view of implant <NUM> in the same insertion position of <FIG>. Referring to <FIG>, in the deployed position driven end <NUM> of blade actuating member <NUM> may be disposed proximally to guide opening <NUM> of cap <NUM> (i.e., the entirety of blade actuating member <NUM> is disposed within implant <NUM>). With implant <NUM> in the deployed position, first blade <NUM> and second blade <NUM> are extended outwards from superior side <NUM> and inferior side <NUM>, respectively, so as to be inserted into adjacent vertebral bodies.

In some embodiments, one or more blades could be deployed at a slight angle, relative to the normal directions on the superior and inferior surfaces of the implant. In some embodiments, one or more blades could be oriented at an angle between <NUM> and <NUM> degrees. In other embodiments, one or more blades could be oriented at an angle that is greater than <NUM> degrees. In the exemplary embodiment shown in <FIG>, first blade <NUM> and second blade <NUM> are both oriented at a slight angle from normal axis <NUM>. Specifically, first blade <NUM> forms a first angle <NUM> with normal axis <NUM> and second blade <NUM> forms a second angle <NUM> with normal axis <NUM>. In one embodiment, first angle <NUM> and second angle <NUM> are both approximately <NUM> degrees. Angling the blades in this way may help keep first blade <NUM> and second blade <NUM> approximately centered in the adjacent vertebrae upon deployment.

The extension of each blade could vary in different embodiments. In some embodiments, a blade could extend outwardly by a length between <NUM> and <NUM>% of the depth of an implant. In still other embodiments, combined blade height could extend outwardly by a length between <NUM> and <NUM>% of the depth of an implant. In the exemplary embodiment shown in <FIG>, first blade <NUM> and second blade <NUM> combined may be capable of extending outwardly from implant <NUM> by an amount equal to <NUM>% of the depth of implant <NUM>. This can be done while still keeping the blades fully retracted within implant <NUM> since the blades are guided by two robust parallel tracks in body <NUM> and also by angled cross channels in blade actuating member <NUM>, thus constraining all six axes of motion. In other embodiments, the combined blade height at deployment could be less than <NUM>%. In one embodiment, the implant could be designed so that the combined blade height is less than <NUM> to reduce the risk of fracturing the adjacent vertebral bodies.

<FIG> is a schematic isometric view of first blade <NUM>. First blade <NUM>, or simply blade <NUM>, includes an outer edge <NUM>, an inner edge <NUM>, a first lateral edge <NUM> and a second lateral edge <NUM>. These edges bind a distal face <NUM> (i.e., a face oriented in the distal direction) and a proximal face <NUM> (i.e., a face oriented in the proximal direction).

In different embodiments, the geometry of a blade could vary. In some embodiments, a blade could have a substantially planar geometry such that the distal face and the proximal face of the blade are each parallel with a common plane. In other embodiments, a blade could be configured with one or more bends. In some embodiments, a blade can have a channel-like geometry (ex. "C"-shaped or "S"-shaped). In the embodiment shown in <FIG>, blade <NUM> has a U-shaped geometry with flanges. In particular, blade <NUM> a first channel portion <NUM>, a second channel portion <NUM> and a third channel portion <NUM>. Here, the first channel portion <NUM> is angled with respect to second channel portion <NUM> at a first bend <NUM>. Likewise, third channel portion <NUM> is angled with respect to second channel portion <NUM> at second bend <NUM>. Additionally, blade <NUM> includes a first flange <NUM> extending from first channel portion <NUM> at a third bend <NUM>. Blade <NUM> also includes second flange <NUM> extending from third channel portion <NUM> at fourth bend <NUM>. This geometry for blade <NUM> helps provide optimal strength for blade <NUM> compared to other planar blades of a similar size and thickness, and allowing for greater graft volume.

In the exemplary embodiment, the outer edge <NUM> is a penetrating edge configured to be implanted within an adjacent vertebral body. To maximize penetration, outer edge <NUM> may be sharpened so that blade <NUM> has an angled surface <NUM> adjacent outer edge <NUM>. Moreover, in some embodiments, first lateral edge <NUM> and second lateral edge <NUM> are also sharpened in a similar manner to outer edge <NUM> and may act as extensions of outer edge <NUM> to help improve strength and penetration.

A blade includes provisions for coupling with a blade actuating member. According to the invention, a blade includes a protruding portion. In some embodiments, the protruding portion can extend away from a face of the blade and may fit within a channel in a blade actuating member. Referring to <FIG>, blade <NUM> includes a protruding portion <NUM> that extends from proximal face <NUM>. Protruding portion <NUM> may generally be sized and shaped to fit within a channel of blade actuating member <NUM> (i.e., first channel <NUM> shown in <FIG>). In particular, the cross-sectional shape may fit within a channel in blade actuating member <NUM>. In some cases, the cross-sectional width of protruding portion <NUM> may increase between a proximal portion <NUM> and a distal portion <NUM> allowing protruding portion <NUM> to be interlocked within a channel as discussed in detail below.

A protruding portion may be oriented at an angle on a blade so as to fit with an angled channel in a blade actuating member. In the embodiment of <FIG>, protruding portion <NUM> may be angled with respect to inner edge <NUM> such that blade <NUM> is vertically oriented within implant <NUM> when protruding portion <NUM> is inserted within first channel <NUM>. In other words, the longest dimension of protruding portion <NUM> may form an angle <NUM> with inner edge <NUM>.

Although the above discussion is directed to first blade <NUM>, it may be appreciated that similar principles apply for second blade <NUM>. In particular, in some embodiments, second blade <NUM> may have a substantially identical geometry to first blade <NUM>.

<FIG> is a schematic side view of an embodiment of blade actuating member <NUM>. An isometric view of blade actuating member <NUM> is also shown in <FIG>. Referring to <FIG> and <FIG>, blade actuating member <NUM> may include a driven shaft portion <NUM> and a blade engaging portion <NUM>. Driven shaft portion <NUM> further includes driven end <NUM>.

In some embodiments, driven end <NUM> can include one or more engaging features. For example, driven end <NUM> can include a threaded opening <NUM>, as best seen in <FIG>. In some embodiments, threaded opening <NUM> may receive a tool with a corresponding threaded tip. With this arrangement, driven end <NUM> can be temporarily mated with the end of a tool used to impact blade actuating member <NUM> and drive set of blades <NUM> into adjacent vertebrae. This may help keep the driving tool and driven end <NUM> aligned during the impact and reduce any tendency of the driving tool to slip with respect to driven end <NUM>. Using mating features also allows driven end <NUM> to be more easily "pulled" distally from implant <NUM>, which can be used to retract blades <NUM>, should it be necessary to remove implant <NUM> or re-position the blades.

Blade engaging portion <NUM> may comprise a superior surface <NUM>, an inferior surface <NUM>, a first side surface <NUM> and a second side surface <NUM>. Here, first side surface <NUM> may be an anterior facing side and second side surface <NUM> may be a posterior facing side. In other embodiments, however, first side surface <NUM> could be a posterior facing side and second side surface <NUM> could be an anterior facing side.

A blade actuating member can include provisions for coupling with one or more blades. In some embodiments, a blade actuating member can include one or more channels. In the exemplary embodiment of <FIG>, blade engaging portion <NUM> includes a first channel <NUM> and a second channel <NUM> (shown in phantom in <FIG>). First channel <NUM> may be disposed in first side surface <NUM> of blade actuating member <NUM> while second channel <NUM> may be disposed in second side surface <NUM> of blade actuating member <NUM>.

Each channel is seen to extend at an angle between superior surface <NUM> and inferior surface <NUM> of a blade engaging portion <NUM>. For example, as best seen in <FIG>, first channel <NUM> has a first end <NUM> open along superior surface <NUM> and a second end <NUM> open along inferior surface <NUM>. Moreover, first end <NUM> is disposed closer to driven shaft portion <NUM> than second end <NUM>. Likewise, second channel <NUM> includes opposing ends on superior surface <NUM> and inferior surface <NUM>, though in this case the end disposed at superior surface <NUM> is disposed further from driven shaft portion <NUM> than the end disposed at inferior surface <NUM>.

In different embodiments, the angle of each channel could be selected to provide proper blade extension for varying implant sizes. As used herein, the angle of a channel is defined to be the angle formed between the channel and a transverse plane of the blade actuating member. In the embodiment of <FIG>, first channel <NUM> forms a first angle <NUM> with transverse plane <NUM> of blade actuating member <NUM>, while second channel <NUM> forms a second angle <NUM> with transverse plane <NUM>. In the exemplary embodiment, first angle <NUM> and second angle <NUM> are equal to provide balanced reactive forces as the blades are deployed. By configuring the blades and blade actuating member in this manner, each blade is deployed about a centerline (e.g., transverse plane <NUM>) of the blade actuating member, which helps minimize friction and binding loads between these parts during blade deployment. Additionally, the arrangement helps provide balanced reaction forces to reduce insertion effort and friction.

In different embodiments, the angle of each channel could vary. In some embodiments, a channel could be oriented at any angle between <NUM> and <NUM> degrees. In other embodiments, a channel could be oriented at any angle between <NUM> and <NUM> degrees. Moreover, in some embodiments, the angle of a channel may determine the angle of a protruding portion in a corresponding blade. For example, the angle <NUM> formed between protruding portion <NUM> and inner edge <NUM> of blade <NUM> (see <FIG>) may be approximately equal to the angle <NUM> formed between first channel <NUM> and transverse plane <NUM>. This keeps the outer penetrating edge of blade <NUM> approximately horizontal so that the degree of penetration does not vary at different sections of the blade.

As seen in <FIG>, each channel has a cross-sectional shape that facilitates a coupling or fit with a corresponding portion of a blade. As an example, channel <NUM> has an opening <NUM> on first side surface <NUM> with an opening width <NUM>. At a location <NUM> that is proximal to opening <NUM>, channel <NUM> has a width <NUM> that is greater than opening width <NUM>. This provides a cross-sectional shape for channel <NUM> that allows for a sliding joint with a corresponding part of first blade <NUM>. In the exemplary embodiment, first channel <NUM> and second channel <NUM> are configured with dovetail cross-sectional shapes. In other embodiments, however, other various cross-sectional shapes could be used that would facilitate a similar sliding joint connection with a correspondingly shaped part. In other words, in other embodiments, any geometry for a blade and a blade actuating member could be used where the blade and blade actuating member include corresponding mating surfaces of some kind.

In some embodiments, blade engaging portion <NUM> may be contoured at the superior and inferior surfaces to resist subsidence and allow maximum blade deployment depth. This geometry may also help to keep the blade engaging portion <NUM> centered between vertebral endplates. As an example, the contouring of superior surface <NUM> and inferior surface <NUM> in the present embodiment is best seen in the enlarged cross-sectional view of <FIG>.

<FIG> illustrate a schematic exploded isometric view and a schematic view, respectively, of blade actuating member <NUM> and set of blades <NUM>. Referring to <FIG>, protruding portion <NUM> of first blade <NUM> fits into first channel <NUM>. Likewise, protruding portion <NUM> of second blade <NUM> fits into second channel <NUM>.

Each channel may be associated with a first channel direction and an opposing second channel direction. For example, as best seen in <FIG>, first channel <NUM> may be associated with a first channel direction <NUM> that is directed towards superior surface <NUM> along the length of first channel <NUM>. Likewise, first channel <NUM> includes a second channel direction <NUM> that is directed towards inferior surface <NUM> along the length of first channel <NUM>.

With first protruding portion <NUM> of first blade <NUM> disposed in first channel <NUM>, first protruding portion <NUM> can slide in first channel direction <NUM> or second channel direction <NUM>. As first protruding portion <NUM> slides in first channel direction <NUM>, first blade <NUM> moves vertically with respect to blade actuating member <NUM> such that first blade <NUM> extends outwardly on a superior side of implant <NUM> (see <FIG>). As first protruding portion <NUM> slides in second channel direction <NUM>, first blade <NUM> moves vertically with respect to blade actuating member <NUM> such that first blade <NUM> is retracted within outer structure <NUM> of implant <NUM> (see <FIG>). In a similar manner, second protruding portion <NUM> of second blade <NUM> may slide in first and second channel directions of second channel <NUM> such that second blade <NUM> can be extended and retracted from implant <NUM> on an inferior side (see <FIG>). By using this configuration, blade actuating member <NUM> propels both blades in opposing directions thereby balancing the reactive loads and minimizing cantilevered loads and friction on the guide bar.

As shown in the cross section of <FIG>, the fit between each blade and the respective channel in blade actuating member <NUM> may be configured to resist motion in directions orthogonal to the corresponding channel directions. For example, with first protruding portion <NUM> inserted within first channel <NUM>, first blade <NUM> can translate along first channel direction <NUM> or second channel direction <NUM>, but may not move in a direction <NUM> that is perpendicular to first channel direction <NUM> and second channel direction <NUM> (i.e., blade <NUM> cannot translate in a direction perpendicular to the length of first channel <NUM>). Specifically, as previously mentioned, the corresponding cross-sectional shapes of first channel <NUM> and first protruding portion <NUM> are such that first protruding portion <NUM> cannot fit through the opening in first channel <NUM> on first side surface <NUM> of blade actuating member <NUM>.

In some embodiments, each protruding portion forms a sliding dovetail connection or joint with a corresponding channel. Using dovetail tracks on the blade actuating member and corresponding dovetail features on the posterior and anterior blades allows axial movement along the angle of inclination while preventing disengagement under loads encountered during blade impaction and retraction. For example, in <FIG>, first protruding portion <NUM> forms a sliding dovetail joint with first channel <NUM>. Of course, the embodiments are not limited to dovetail joints and other fits/joints where the opening in a channel is smaller than the widest part of a protruding portion of a blade could be used.

It may be appreciated that in other embodiments, the geometry of the interconnecting parts between a blade and a blade actuating member could be reversed. For example, in another embodiment, a blade could comprise one or more channels and a blade actuating member could include corresponding protrusions to fit in the channels. In such embodiments, both the protruding portion of the blade actuating member and the channels in the blades could have corresponding dovetail geometries.

<FIG> illustrates a schematic view of body <NUM>. Body <NUM> may provide the posterior and anterior sides of outer structure <NUM>, as well as at least one lateral side of outer structure <NUM>.

In some embodiments, the posterior and anterior sides of a body may both have a truss-like or lattice-like geometry. In other embodiments, the posterior and/or anterior sides could be configured as solid walls with one or more openings. In the exemplary embodiment shown in <FIG>, posterior side <NUM> and anterior side <NUM> of body <NUM> have a truss-like geometry comprised of diagonally oriented supports <NUM>. Although a particular pattern of supports is shown in <FIG>, other embodiments could have supports arranged in any other pattern, including any truss-like and/or lattice-like patterns.

The configuration of supports <NUM> shown for the embodiment of <FIG> may facilitate the manufacturing process. In particular, this configuration may permit 3D Printing via laser or electron beam with minimal support structures by orienting the diagonal supports <NUM> more than <NUM> degrees in relation to the build direction. Although the embodiment of <FIG> uses a truss-structure with openings between supports, other embodiments could include thin walls of material to fill in some of the openings between supports. Using an open truss design and/or a truss design with thin walls may help to improve visibility of adjacent bony anatomy under X-ray fluoroscopy while still providing sufficient structural support and rigidity to withstand all testing requirements and the clinical loading of an implant.

In other embodiments, a body may not have a truss or lattice-like geometry. For example, an alternative design for a body <NUM> is shown in <FIG>. As seen in <FIG>, body <NUM> may be similar to body <NUM> in some respects. However, rather than having a truss-like geometry, body <NUM> uses a solid geometry with oval-shaped openings <NUM> on both the anterior and posterior sides. Other embodiments, not pictured in the figures, include round or rectangular openings in otherwise solid geometry of the anterior, posterior, or lateral sides.

Embodiments can also include one or more blade retaining portions. A blade retaining portion may receive any part of a blade, including one or more edges and/or faces of the blade. In one embodiment, a body includes blade retaining portions to receive the lateral edges of each blade. As seen in <FIG>, body <NUM> includes a first blade retaining portion <NUM> and a second blade retaining portion <NUM> on posterior side <NUM>. First blade retaining portion <NUM> is comprised of a first blade retaining channel extending through the depth of body <NUM> that receives first lateral edge <NUM> of first blade <NUM> (see <FIG>). Likewise, second blade retaining portion <NUM> is comprised of a second blade retaining channel extending through the depth of body <NUM> that receives second lateral edge <NUM> of first blade <NUM> (see <FIG>). Body <NUM> also includes third blade retaining portion <NUM> and fourth retaining portion <NUM> for receiving the lateral edges of second blade <NUM>. This configuration may help maximize available bone graft volume within the implant since the lateral edges of the blades serve as tracks for translation. Specifically, this limits the need for additional track members on the blade that would take up additional volume in the implant. Furthermore, the arrangement of the retaining channels and the associated blade edges results in most of the volume of the retaining channels being filled by the blade edges in the retracted position, which helps prevent any graft material or BGPM from entering the retaining channels and inhibiting normal blade travel.

<FIG> illustrate isometric views of a distal side and a proximal side, respectively, of cap <NUM>. Referring to <FIG>, cap <NUM> includes one or more openings for engaging different parts of implant <NUM>. For example, cap <NUM> may include a first pin hole <NUM> and a second pin hole <NUM> that are configured to receive pin <NUM> and pin <NUM>, respectively (see <FIG>). Moreover, first pin hole <NUM> and second pin hole <NUM> (shown in <FIG>) of cap <NUM> may be aligned with corresponding holes in the body.

As previously discussed, cap <NUM> may include an opening <NUM> to receive a locking screw or other fastener. Additionally, cap <NUM> may include guide opening <NUM> that receives a portion of blade actuating member <NUM>. In some embodiments, guide opening <NUM> may have a shape that matches the cross-sectional shape of a driven portion of a blade actuating member. In some embodiments, both guide opening <NUM> and driven shaft portion <NUM> of blade actuating member <NUM> have rectangular cross-sectional shapes. This configuration may allow axial motion, but control rotational and angular loads that could result during blade impaction as exemplified in <FIG>.

In some embodiments, cap <NUM> may include attachment points for an insertion instrument. For example, as seen in <FIG>, cap <NUM> may include a first cavity <NUM> and a second cavity <NUM> that may receive the ends of an insertion tool to improve the grip of the tool on implant <NUM> during insertion into (or removal from) between the vertebrae of the spine.

As seen in <FIG>, in some embodiments, cap <NUM> may also include a cavity <NUM> for receiving a part of body <NUM>. Specifically, cavity <NUM> may receive a fastening end <NUM> of body <NUM> (see <FIG>), which includes a pin receiving opening <NUM> shown in <FIG>, so that fastening end <NUM> can be retained within cavity <NUM> once second pin <NUM> has been inserted in the assembled and un-deployed state shown in <FIG>.

<FIG> is a schematic top view of implant <NUM> in which attachments between the blades and other components of implant <NUM> are visible. <FIG> is a schematic enlarged view of a region <NUM> of implant <NUM> including first blade <NUM> and a portion of blade actuating member <NUM>, in which several attachment points are clearly visible.

Referring to <FIG>, implant <NUM> uses a three-point attachment configuration for each of first blade <NUM> and second blade <NUM>. Specifically, each blade is received along its lateral edges by two blade retaining portions, and also coupled to blade actuating member <NUM> using the dovetail connection described above. As seen in <FIG>, first lateral edge <NUM> of first blade <NUM> is received within the first blade retaining channel of first blade retaining portion <NUM>. Second lateral edge <NUM> of first blade <NUM> is received within a second retaining channel of second blade retaining portion <NUM>. Moreover, distal face <NUM> of first blade <NUM> remains unattached to any other elements of implant <NUM>. Not only does first blade <NUM> remain unattached along distal face <NUM>, but the entirety of distal face <NUM> between first lateral edge <NUM> and second lateral edge <NUM> is spaced apart from (i.e., not in contact with) all other elements of implant <NUM>. Further, second blade <NUM> is likewise attached at its lateral edges to corresponding blade retaining portions and also coupled to blade actuating member <NUM> using a sliding dovetail connection. Thus, first blade <NUM> and second blade <NUM> are held in implant <NUM> using a three-point attachment configuration that may limit unwanted friction on first blade <NUM> and second blade <NUM> during impaction. It may be appreciated that the fit between each blade and each blade retaining channel may provide sufficient clearance to allow for translation of the blades along the retaining channels. In other words, the fit may not be so tight as to impede movement of the lateral edges within the retaining channels.

In different embodiments, the cross-sectional geometry of channels in one or more blade retaining portions could vary. In some embodiments, the cross-sectional geometry could be rounded. In the embodiment shown in <FIG>, blade retaining portion <NUM> is seen to have a rectangular blade retaining channel <NUM>. This rectangular geometry for the blade tracks or channels and tolerance allows for precise axial travel without binding from actuation ramp angular variations. Similarly, the remaining blade retaining portions of the embodiment of <FIG> have similar rectangular shapes.

In some embodiments, the lateral edges of each blade may remain in the tracks or channels of each blade retaining portion while the blades are retracted to prevent bone graft material from restricting free deployment of the blades.

Using an interlocking joint, such as a dovetail sliding joint, to connect the blades and a blade actuating member helps prevent the blades from decoupling from the blade actuating member during impact. Additionally, with an interlocking joint the blade actuating member can be used to retract the blades.

<FIG> illustrate several schematic views of implant <NUM> during an impact sequence (<FIG>) as well as during a step of retracting the blades (<FIG>). In <FIG>, outer structure <NUM> of implant <NUM> is shown in phantom to better show blade actuating member <NUM>, first blade <NUM> and second blade <NUM>. Also, each of <FIG> include an enlarged cut-away view of a section of blade actuating member <NUM>, first blade <NUM> and second blade <NUM> to better illustrate the coupling between these parts during actuation.

In <FIG>, implant <NUM> is in the insertion position, with first blade <NUM> and second blade <NUM> fully retracted within outer structure <NUM>. Next, as seen in <FIG>, an impacting force <NUM> is applied to driven end <NUM> of blade actuating member <NUM>. As blade actuating member <NUM> is translated towards second lateral side <NUM> of implant <NUM>, blade actuating member <NUM> applies forces to first blade <NUM> and second blade <NUM> along first channel <NUM> and second channel <NUM>, respectively. Specifically, the orientation of first channel <NUM> is such that first blade <NUM> is forced towards the superior side of implant <NUM>. Likewise, the orientation of second channel <NUM> is such that second blade <NUM> is forced towards the inferior side of implant <NUM>. Furthermore, the interlocking connection between first protruding portion <NUM> and first channel <NUM> (as well as between second protruding portion <NUM> and second channel <NUM>) means that both blades remain coupled to the motion of blade actuating member <NUM> at all times. It should be noted that since both blades are restricted from moving in a longitudinal direction (i.e., the direction of motion of blade actuating member <NUM>), the resulting motion of each blade is purely vertical. Moreover, using the dovetail shaped protruding portions for each blade means the protruding portions are both lifting at the center line to limit any cocking force or rotational moments that could result in increased (friction) resistance to motion or binding of these moving parts.

Using this configuration, the forces deploying the blades are balanced through the blade actuating member <NUM> in order to minimize friction and binding between driven shaft portion <NUM> and opening <NUM> in cap <NUM> (see <FIG>), which helps to guide blade actuating member <NUM> and keep its motion restricted to directions parallel to the longitudinal axis (see <FIG>).

In <FIG>, implant <NUM> has been placed in the fully deployed position, with both first blade <NUM> and second blade <NUM> fully extended from implant <NUM>. As seen in the enlarged cut-away view, both first blade <NUM> and second blade <NUM> remain coupled with blade actuating member <NUM> when implant <NUM> is in the fully deployed position. Because of this coupling, the motion of blade actuating member <NUM> can be reversed to retract first blade <NUM> and second blade <NUM>, as shown in <FIG>.

Referring to <FIG>, driven end <NUM> of blade actuating member <NUM> may be pulled in an opposing direction to the motion shown in <FIG>. For example, in some embodiments a delivery tool can be coupled to driven end <NUM> using a threaded connector. Then, as the tip of the delivery tool is retracted a retracting or pulling force <NUM> may be applied to drive end <NUM>. As blade actuating member <NUM> (and specifically, blade engaging portion <NUM>) is pulled towards first lateral side <NUM> of implant <NUM>, blade actuating member <NUM> applies forces to first blade <NUM> and second blade <NUM> along first channel <NUM> and second channel <NUM>, respectively. Specifically, the orientation of first channel <NUM> is such that first blade <NUM> is forced towards the inferior side of implant <NUM>. Likewise, the orientation of second channel <NUM> is such that second blade <NUM> is forced towards the superior side of implant <NUM>. Although not shown, applying sufficient force at driven end <NUM> may result in full retraction of first blade <NUM> and second blade <NUM> so that implant <NUM> is returned to the insertion position shown in <FIG>.

<FIG> illustrate several schematic views of locking screw <NUM>, according to an embodiment. Locking screw <NUM> includes a flanged head <NUM> with a rounded segment <NUM> and a flat segment <NUM>. Locking screw <NUM> further includes a threaded body <NUM> and a rotation restricting groove <NUM>.

Rotation restricting groove <NUM> may include a first groove end <NUM> and a second groove end <NUM> (see <FIG>). As seen in <FIG>, rotation restricting groove <NUM> may extend less than a full turn around the circumference of threaded body <NUM>.

<FIG> illustrate schematic views of an implant, including an isometric view and an enlarged cross-sectional view taken near a transverse plane of implant <NUM>. <FIG> is a schematic view of implant <NUM> with locking screw <NUM> in an "unlocked" rotational position. In this unlocked rotational position, locking screw <NUM> is rotated so that flat segment <NUM> is aligned with an adjacent edge of opening <NUM>, thereby allowing driven shaft portion <NUM> of blade actuating member <NUM> to pass through opening <NUM> without impedance.

<FIG> is a schematic view of implant <NUM> with locking screw <NUM> in a "locked" rotational position. In this locked rotational position, locking screw <NUM> is rotated so that rounded segment <NUM> extends over opening <NUM> and blocks the passage of driven end <NUM> of blade actuating member <NUM> through opening <NUM>. It may be appreciated that locking screw <NUM> can only be placed in the locked rotational position once driven end <NUM> has been pushed completely through opening <NUM> and is located proximally to locking screw <NUM>.

As seen in <FIG>, pin <NUM> may be disposed within rotation restricting groove <NUM> (see <FIG>) of locking screw <NUM>. Moreover, rotation restricting groove <NUM> may be sized and dimensioned to allow locking screw to be rotated between the locked and unlocked positions, but not rotated to the point of completely backing out of implant <NUM>. For example, with pin <NUM> engaged in rotation restricting groove <NUM>, locking screw <NUM> may only be rotated between a first rotational position where pin <NUM> is disposed against first groove end <NUM> and a second rotational position where pin <NUM> is disposed against second groove end <NUM>.

It may be appreciated that in some embodiments a blade actuating member (e.g., blade actuating member <NUM>) may function to support adjacent vertebral bodies. This is can be accomplished by using a blade actuating member with a height similar to the height of the outer support structure so that the superior and inferior surfaces of the blade actuating member may come into contact with the vertebral bodies following implantation. Since the blade actuating member functions as a load bearing structure within the implant, this may free up additional space in the implant otherwise occupied by additional support structures, thereby increasing the internal volume available for bone graft or BGPMs.

In different embodiments, the size of an implant could vary. In some embodiments, an implant could have any length. Embodiments could have lengths ranging from <NUM> to <NUM>. In some cases, a manufacturer could provide multiple implant options with lengths varying between <NUM> and <NUM> in <NUM> increments. In some embodiments, an implant could have any height. Embodiments could have a height ranging from <NUM> to <NUM>. In some cases, a manufacturer could provide implants with heights varying from <NUM> to <NUM> in <NUM> increments. Embodiments could have widths (i.e., size along the posterior-anterior axis) of <NUM>, <NUM>, <NUM> as well as other sizes.

Embodiments can also be constructed with various lordosis angles, that is, angles of incline between the posterior and anterior sides. Embodiments could be configured with lordosis angles of <NUM>, <NUM> and <NUM> degrees, for example. In other embodiments, other lordosis angles could be used for an implant.

Embodiments may optionally include one or more alignment features. Exemplary alignment features include, but are not limited to, windows for fluoroscopy positioning, windows for blade deployment validation, windows for aligning a blade actuating member with one or more blades, as well as various other kinds of alignment features. Referring to <FIG>, body <NUM> of implant <NUM> includes a central alignment window <NUM>. Additionally, blade <NUM> includes an alignment window <NUM>. Alignment window <NUM> may align with central alignment window <NUM> when blade <NUM> is fully retracted. Moreover, blade actuating member <NUM> includes a first alignment window <NUM> and a second alignment window <NUM>. Window <NUM> and window <NUM> may align with the implant body center line when blade <NUM> and blade <NUM> are fully deployed and retracted. One or more of these windows (i.e., central alignment window <NUM>, first alignment window <NUM> and/or second alignment window <NUM>) may facilitate fluoroscopy positioning and may be used to confirm blade deployment. For example, in some cases, when first blade <NUM> and second blade <NUM> are fully deployed, the blades may clear first alignment window <NUM> of blade actuating member <NUM>.

Some embodiments may also include one or more stroke limiting stops. For example, the embodiment of implant <NUM> shown in <FIG> includes a first stroke limiting stop <NUM> and second stroke limiting stop <NUM> on blade actuating member <NUM>. These stops may help prevent over travel of blade actuating member <NUM>. Specifically, stop <NUM> and stop <NUM> may contact the internal surfaces of body <NUM>.

The various components of an implant may be fabricated from biocompatible materials suitable for implantation in a human body, including but not limited to, metals (e.g. titanium, titanium alloy, stainless steel, cobalt-chrome,or other metals), synthetic polymers (e.g. PEEK or PEKK), ceramics, and/or their combinations, depending on the particular application and/or preference of a medica! practitioner.

Generally, the implant can be formed from any suitable biocompatible, non-degradable material with sufficient strength. Typical materials include, but are not limited to, titanium, biocompatible titanium alloys (e.g. Titanium Aluminides (including gamma Titanium Aluminides), Ti<NUM>-Al<NUM>-V ELI (ASTM F <NUM> and ASTM F <NUM>), or Ti<NUM>-Al<NUM>-V (ASTM F <NUM>, ASTM F <NUM>, and ASTM F <NUM>) and inert, biocompatible polymers, such as polyether ether ketone (PEEK) (e.g. PEEK-OPTIMA®, Invibio Inc, Zeniva®, Solvay Inc. , or others ). Optionally, the implant contains a radiopaque marker to facilitate visualization during imaging when constructed of radiolucent biomaterials.

In different embodiments, processes for making an implant can vary. In some embodiments, the entire implant may be manufactured and assembled via traditional and CNC machining, injection-molding, cast or injection molding, insert-molding, co-extrusion, pultrusion, transfer molding, overmolding, compression molding, <NUM>-Dimensional (<NUM>-D) printing, dip-coating, spray-coating, powder-coating, porous-coating, milling from a solid stock material and their combinations.

In one embodiment, body <NUM> may be produced by Direct Metal Laser Sintering (DMLS) using powder Ti-6AI-4V ELI, and then traditional or CNC machined in specific locations to precise dimensions. Moreover, in one embodiment, blade actuating member <NUM>, first blade <NUM>, second blade <NUM>, cap <NUM>, pins <NUM> and locking screw <NUM> may also be made of a material including titanium.

Some embodiments may use a bone growth promoting material, including bone graft or bone graft substitute material. As used herein, a "bone growth promoting material" (BGPM) is any material that helps bone growth. Bone growth promoting materials may include provisions that are freeze dried onto a surface or adhered to the metal through the use of linker molecules or a binder. Examples of bone growth promoting materials are any materials including bone morphogenetic proteins (BMPs), such as BMP-<NUM>, BMP-<NUM>, BMP-<NUM>, BMP-<NUM>, and BMP-<NUM>. These are hormones that convert stem cells into bone forming cells. Further examples include recombinant human BMPs (rhBMPs), such as rhBMP-<NUM>, rhBMP-<NUM>, and rhBMP-<NUM>. Still further examples include platelet derived growth factor (PDGF), fibroblast growth factor (FGF), collagen, BMP mimetic peptides, as well as RGD peptides. Generally, combinations of these chemicals may also be used. These chemicals can be applied using a sponge, matrix or gel.

Some bone growth promoting materials may also be applied to an implantable prosthesis through the use of a plasma spray or electrochemical techniques. Examples of these materials include, but are not limited to, hydroxyapatite, beta tri-calcium phosphate, calcium sulfate, calcium carbonate, as well as other chemicals.

A bone growth promoting material can include, or may be used in combination with a bone graft or a bone graft substitute. A variety of materials may serve as bone grafts or bone graft substitutes, including autografts (harvested from the iliac crest of the patient's body), allografts, demineralized bone matrix, and various synthetic materials.

Some embodiments may use autograft. Autograft provides the spinal fusion with calcium collagen scaffolding for the new bone to grow on (osteoconduction). Additionally, autograft contains bone-growing cells, mesenchymal stem cells and osteoblast that regenerate bone. Lastly, autograft contains bone-growing proteins, including bone morphogenic proteins (BMPs), to foster new bone growth in the patient.

Bone graft substitutes may comprise synthetic materials including calcium phosphates or hydroxyapatites, stem cell containing products which combine stem cells with one of the other classes of bone graft substitutes, and growth factor containing matrices such as INFUSE® (rhBMP-<NUM>-containing bone graft) from Medtronic, Inc.

It should be understood that the provisions listed here are not meant to be an exhaustive list of possible bone growth promoting materials, bone grafts or bone graft substitutes.

In some embodiments, BGPM may be applied to one or more outer surfaces of an implant. In other embodiments, BGPM may be applied to internal volumes within an implant. In still other embodiments, BGPM may be applied to both external surfaces and internally within an implant.

Claim 1:
An implant (<NUM>), comprising:
a body (<NUM>), the body having a longitudinal axis (<NUM>) extending from a first lateral side (<NUM>) to a second lateral side (<NUM>) of the body;
a blade (<NUM>), the blade (<NUM>) having a retracted position in the body (<NUM>) and an extended position where the blade (<NUM>) extends outwardly from the body (<NUM>);
a blade actuating member (<NUM>) that can translate through the body (<NUM>) in directions parallel to the longitudinal axis (<NUM>);
the blade actuating member (<NUM>) including a channel (<NUM>), wherein the channel (<NUM>) extends between a superior surface (<NUM>) and an inferior surface (<NUM>) of the blade actuating member (<NUM>), and wherein the channel (<NUM>) defines a first channel direction (<NUM>) and an opposing second channel direction (<NUM>);
the blade (<NUM>) including a protruding portion (<NUM>) configured to fit within the channel (<NUM>);
wherein when the blade actuating member (<NUM>) is moved in a first direction along the longitudinal axis (<NUM>), the protruding portion (<NUM>) follows the channel (<NUM>) in the first channel direction (<NUM>) and the blade (<NUM>) moves towards the extended position;
wherein when the blade actuating member (<NUM>) is moved in a second direction (<NUM>) opposite the first direction, the protruding portion (<NUM>) follows the channel (<NUM>) in the second channel direction (<NUM>) and the blade (<NUM>) moves towards the retracted position; and
wherein the blade (<NUM>) has an outer edge (<NUM>), an inner edge (<NUM>) disposed opposite the outer edge (<NUM>), a first lateral edge (<NUM>), and a second lateral edge (<NUM>) disposed opposite the first lateral edge (<NUM>);
characterized in that:
the blade (<NUM>) is only in contact with the body (<NUM>) along the first lateral edge (<NUM>) and the second lateral edge (<NUM>).