Expandable interbody implant and breakoff screw

An expandable implant may include an expandable body defined by a superior endplate and an inferior endplate that are hingedly coupled and may be expanded and lordosed. The superior endplate may include a first core having a distal engagement surface and the inferior endplate may include a second core having a proximal engagement surface and a threaded screw aperture. The implant may include a threaded breakoff screw disposed in the threaded screw aperture and movable between a locked position and an unlocked position, for example. In the locked position, the threaded locking screw may urge the distal engagement surface of the first core into direct contact with the proximal engagement surface of the second core. When broken, the breakoff screw may comprise a recessed fracture surface.

FIELD

In one aspect, the present technology is generally related to an externally driven expandable interbody implant for use in a medical procedure related to the spine. In some embodiments, disclosed implants may be used in an anterior cervical discectomy and fusion (ACDF) procedure although other uses in other areas of the spine or between two bones are also contemplated. In another aspect, the present technology is generally related to a breakoff screw having a recessed fracture surface that may be used with various medical implants including an interbody implant.

BACKGROUND

Mechanically operated interbody implants may be used to align and/or realign a patient's spine during a medical procedure and/or for purposes of fusion, degenerative tissue and/or trauma/repair procedures. Conventional implants designed for the Thoracic and Lumbar region of the spine often include top and bottom endplates and a mechanical means to separate the top and bottom endplates. The mechanical mechanisms to separate the top and bottom endplates are often cumbersome and require a large footprint that is often unsuitable, for example, for ACDF type surgeries of the cervical portion of the spine. Additionally, conventional breakoff screws may lack a recessed fracture surface and sharp ends of an exposed fracture surface may damage or cut adjacent soft tissues of a patient.

SUMMARY

The techniques of this disclosure generally relate to an expandable interbody implant including a superior endplate and an inferior endplate hingedly coupled and which may further include a locking element to secure the inferior endplate and superior endplate in a particular configuration, for example. The superior and inferior endplates may be moved in a multitude of expanded and/or lordosed or kyphosed or otherwise angled configurations via an external inserter for example. In various embodiments, a locking screw may be a breakoff type screw. In various embodiments at least one breakoff tang on the implant may be used to for gripping of the implant to insert it into a disc space and afterwards the breakoff tang may be broken off and removed. Additionally, in various embodiments the locking screw may be used to grip the implant and insert it into a disc space. Additionally, in various embodiments female recesses, rather than tangs, may be used for gripping of the implant and inserting the implant into a disc space.

In one aspect, the present disclosure provides for an expandable implant movable between a contracted position and an expanded position, for example. The expandable implant may include an expandable body extending from a proximal end to a distal end in a proximal-to-distal direction and extending from a first lateral side to a second lateral side in a widthwise direction, for example. In various embodiments, the expandable body may be defined by a superior endplate and an inferior endplate that are hingedly connected, for example. In various embodiments, the superior endplate includes a first core having a distal engagement surface and the inferior endplate includes a second core having a proximal engagement surface and a threaded screw aperture, for example. In various embodiments, disclosed implants may include a threaded breakoff screw having a fracture surface that is disposed in the threaded screw aperture and movable between a locked position and an unlocked position, for example. In various embodiments, when in the locked position, the breakoff screw urges the distal engagement surface of the first core into direct contact with the proximal engagement surface of the second core, for example.

In another aspect, the disclosure provides for a breakoff screw, including an elongate body extending in a proximal to distal direction along a longitudinal axis, for example. The elongate body may be defined by a proximal portion and a distal portion separated therebetween by a necked down portion forming a recessed fracture surface, for example. In various embodiments, the proximal portion may include a first drive feature and a first flexible tang and a second flexible tang, for example. In various embodiments, the distal portion may include a second drive feature, engagement surface, and an external thread pattern, for example. In some embodiments, the recessed fracture surface is inset with respect to a proximal most surface of the second drive feature.

DETAILED DESCRIPTION

Embodiments of the present disclosure relate generally, for example, to spinal stabilization systems, and more particularly, to surgical instruments for use with spinal stabilization systems. Embodiments of the devices and methods are described below with reference to the Figures.

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

Terms such as “same,” “equal,” “planar,” “coplanar,” “parallel,” “perpendicular,” etc. as used herein are intended to encompass a meaning of exactly the same while also including variations that may occur, for example, due to manufacturing processes. The term “substantially” may be used herein to emphasize this meaning, particularly when the described embodiment has the same or nearly the same functionality or characteristic, unless the context or other statements clearly indicate otherwise.

In various embodiments, components may be coated with a ceramic, titanium, and/or other biocompatible material to provide surface texturing at (a) the macro scale, (b) the micro scale, and/or (c) the nano scale, for example. Similarly, components may undergo a subtractive manufacturing process providing for surface texturing configured to facilitate osseointegration and cellular attachment and osteoblast maturation. Example surface texturing of additive and subtractive manufacturing processes may comprise (a) macro-scale structural features having a maximum peak-to-valley height of about 40 microns to about 500 microns, (b) micro-scale structural features having a maximum peak-to-valley height of about 2 microns to about 40 microns, and/or (c) nano-scale structural features having a maximum peak-to-valley height of about 0.05 microns to about 5 microns. In various embodiments, the three types of structural features may be overlapping with one another, for example. Additionally, such surface texturing may be applied to any surface, e.g., both external exposed facing surfaces of components and internal non exposed surfaces of components. Further discussion regarding relevant surface texturing and coatings is described in, for example, U.S. Pat. No. 11,096,796, titled Interbody spinal implant having a roughened surface topography on one or more internal surfaces, and filed on Mar., 4, 2013—the entire disclosure of which is incorporated herein by reference in its entirety. Accordingly, it shall be understand that any of the described coating and texturing processes of U.S. Pat. No. 11,096,796, may be applied to any component of the various embodiments disclosed herein, e.g., the exposed surfaces and internal surfaces of endplates. Another example technique for manufacturing an orthopedic implant having surfaces with osteoinducting roughness features including micro-scale structures and nano-scale structures is disclosed in U.S. Pat. No. 10,821,000, the entire contents of which are incorporated herein by reference. Additionally, an example of a commercially available product may be the Adaptix™ Interbody System sold by Medtronic Spine and comprising a titanium cage made with Titan nanoLOCK™.

Referring generally toFIGS.1-5various views of an expandable implant100in a collapsed position are illustrated.FIGS.1-2are various perspective views of an expandable implant100.FIG.3is a top down view of an expandable implant100. In the example embodiment, expandable implant100may include a proximal end100P, a distal end100D, and first and second lateral sides100L. Additionally, a pair of bone screw apertures11,21may be positioned on the proximal end100P, for example. In various embodiments, bone screw apertures11,21may comprise a corresponding bone screw retention mechanism11a,21a(may also be referred to as an anti-backout locking mechanism). In the example embodiment, the bone screw retention mechanisms11a,21a,comprise a flexible tang member having a hook portion at an end thereof that allows the flexible tang member to flex outward in a lateral direction away from the corresponding bone screw aperture11,21during initial installation of the bone screw and to flex back inward towards the corresponding bone screw aperture11,21to prevent a corresponding bone screw from backing out. For example, as the bone is installed in bone screw aperture11,21, the bone screw retention mechanism11a,21a,may flex outward as the underside of the head portion contacts inclined surface11c(seeFIG.19).

In various embodiments, and as illustrated inFIGS.1-2, mounting tangs19,29may extend in a proximal direction, for example. In various embodiments, implant100may be referred to as an externally driven expandable implant because an end user or surgeon may use a surgical tool to open and close implant100, e.g. expand implant100. For example, an external tool may adjust the lordotic angle of implant100as will be explained in detail with respect toFIGS.20-25. Once implant100is expanded to an appropriate lordotic angle (also referred to as angle of inclination), an end user may fix the relative angle of the superior endplate10relative to the inferior endplate20by tightening locking screw50, for example. In some embodiments, superior endplate10may be referred to as a “cephalad” endplate and inferior endplate20may be referred to as a “caudal” endplate.

Locking screw50may also be used in other embodiments, such as fixation of posterior rods, fixation of pedicle screws, and other set screw constructs. Additionally, locking screw50may be referred to as a “breakoff screw” in some embodiments.

At least one advantage of relying on an external tool to adjust a lordotic angle of implant100may be the reduction of internal components within implant100relative to other forms of implants relying on various moving mechanisms and/or expansion mechanisms, for example. Accordingly, in various embodiments, implant100may have a relatively large void space in the interior thereof, which may facilitate a fusion process during an ACDF procedure. For example, implant100may have a relatively large internal volume101that is open through the superior endplate10and inferior endplate20which may be packed with bone graft material, for example.

As illustrated inFIG.3, implant100may extend in a proximal-to-distal direction (also referred to as a longitudinal direction) from the proximal end100P to the distal end100D though axis P-D through the center of the implant100, for example. Implant100may extend in a widthwise direction (also referred to as lateral direction) from the first lateral side100L to the second lateral side100L through axis W-W through the center of the implant100and the center of locking screw50, for example. The axis P-D may be perpendicular and/or substantially perpendicular to the axis W-W. For example, the proximal-to-distal direction may be perpendicular to the widthwise direction. Additionally, a width of the implant may taper from a proximal end100P where it is widest towards a distal end100D where it is narrowest.

FIG.4is a side view of an expandable implant100. In the example illustration, it is shown that a superior endplate10is connected to an inferior endplate20such that the superior endplate may pivot about a hinge member40. In the example embodiment, hinge member40comprises an arcuate rail portion of inferior endplate20that extends in the widthwise direction, for example. In the example embodiment, hinge member40may be nested into a corresponding arcuate cavity of the superior endplate10such that superior endplate10may expand and/or otherwise rotate about hinge member40. Additionally, in various embodiments the superior endplate10and/or inferior endplate20may include various engagement elements14for engaging with an adjacent boney structure such as a vertebrae, for example. In the example embodiment, the engagement elements comprise a series of alternating rails and valleys therebetween that extend in the widthwise direction. However, claws, hooks, dimples, spikes, etc. are also contemplated as example engagement elements14. In some embodiments, an acid etching process may be utilized to form a roughened or textured surface to facilitate securing the implant between boney portions and/or suppressing expulsion of implant100.

FIG.5is a rear perspective view of an expandable implant100. In the example illustration it is shown that the distal end100D is narrower than the proximal end100P.FIG.6is a perspective view of the interior of a superior endplate10. In the example illustration, it is shown that the distal end of superior endplate10includes an arcuate channel12of which the hinge member40may be disposed inside of The proximal end of superior endplate10may include a bone screw aperture cutout21bto allow a relief area for a corresponding bone screw to be insert through bone screw aperture21of inferior endplate20, for example. Superior endplate10may also include a core15comprising an aperture15athat extends from a proximal surface15pthereof to a distal surface15dthereof, for example. In various embodiments, aperture15amay be referred to as a “slot” or “screw slot”. In some embodiments, core15may be referred to as a support frame and take a generally rectangular shape. In various embodiments, the distal surface15dmay be curved and generally face the distal end100D of implant100.FIG.7is a perspective view of the interior of an inferior endplate20. In the example illustration, it is shown that the distal end of inferior endplate20includes a hinge member40in the form of an arcuate rail that may be disposed inside of the arcuate channel12of the superior endplate10, for example. The proximal end of inferior endplate20may include a bone screw aperture cutout11bto allow a relief area for a corresponding bone screw to be insert through bone screw aperture11of superior endplate10, for example. Inferior endplate20may also include a core25comprising a threaded aperture25athat extends from a proximal surface25pthereof to a distal surface25dthereof, for example. In some embodiments, core25may be referred to as a support frame and take a generally rectangular shape. In various embodiments, the superior endplate10and inferior endplate20may each be formed a unitary single piece, respectively.

FIG.8is a perspective exploded parts view andFIG.9is an exploded parts view from a side view perspective of an expandable implant100. In the example embodiment, a locking screw50is illustrated. Locking screw50may include an external thread pattern51on an outside circumferential surface thereof, for example. The external thread pattern51of locking screw50may have a size and shape generally corresponding to the threaded aperture25aof core25of inferior endplate20, for example. In various embodiments, an engagement surface54may be disposed adjacent and proximal of external thread pattern51. In the example embodiment, engagement surface54is shaped like a washer and is directly connected to locking screw50. However, in other embodiments, engagement surface54may be a washer or separated element, for example. In some embodiments, engagement surface54may be conically shaped. Engagement surface54may include a relatively planar and/or flat distal surface and/or proximal surface. In various embodiments, a proximal end of set screw50may include an aperture having an internal threaded surface52. For example, a cylindrical shaped proximal end may include an aperture having a thread pattern disposed on an internal circumferential surface of the cylindrical shaped proximal end. In the example embodiment, a first drive feature53aand a second drive feature53bmay be disposed adjacent to and distally with respect to a proximal most end of set screw50. Additionally, first and second drive features53a,53bmay be disposed proximally with respect to engagement surface54. In the example embodiment, drive features53a,53btake a hexalobular shape, although various other shapes such as hexagonal, polygonal, Torx, etc. are also contemplated. In some embodiments, a surgical drive tool having a corresponding socket may be coupled to drive features53a,53bto cause rotation of locking screw50. Similarly, in some alternative embodiments, a drive tool with a protruding threaded member having a thread pattern with a corresponding size and shape to internal threaded surface52may also cause rotation of set screw50.

As seen best inFIG.9, set screw50may also include a breakoff location55, for example. In the example embodiment, breakoff location55is disposed directly between drive features53a,53band is designed to shear off when a sufficient rotational force is applied to a proximal end of set screw50while a distal end of set screw50is stationary, e.g., when set screw50is secured in a locked position and a continued rotational force (torque) is applied to the proximal end of set screw50the drive feature53aand cylindrical end having the internal threaded surface52may breakoff. As also seen best inFIG.9, the inferior endplate20may include a first relief40aand a second relief40bon opposite sides of hinge member40. The first relief40amay have a size and shape corresponding to a size and shape of a first portion12aof superior endplate10and the second relief40bmay have a size and shape corresponding to a size and shape of a second portion12bof superior endplate10, for example. In various embodiments, portions12a,12bmay comprise a hook shape, outdent, and/or protrusion, for example. In the example embodiment, portions12a,12bmay be disposed on opposite sides of channel12and cup hinge member40such that the superior endplate10and inferior endplate20may rotate relative to one another without becoming uncoupled.

FIG.10is a perspective cross section view andFIG.11is a cross section view of expandable implant100. In the example embodiment, the superior endplate10and inferior endplate20are coupled together by hinge member40, and core25may be positioned behind of core15, e.g., core25may be positioned distally with respect to core15. Additionally, the outside external thread pattern51of locking screw50may engage with the threaded aperture25aof the core25and extend through aperture15aof core15. In this way, when locking screw50is rotated, the distal surface15dof core15may engage with the proximal surface25pof core25. For example, by tightening locking screw50the engagement surface54of locking screw50pushes against the proximal surface15pof core15thereby bringing the superior endplate10and inferior endplate20into frictional engagement.

FIG.12is a side view of a superior endplate10for use with at least some expandable implant100embodiments. In the example embodiment, superior endplate10may include an arcuate channel12of which the hinge member40may be disposed inside of In various embodiments, arcuate channel12may be defined by a first circle having a center point at P1and/or a segment of the circle having the center point at P1. The center point P1may define an axis of rotation that superior endplate10may rotate and/or pivot with respect to inferior endplate20. For example, superior endplate10may be hingedly coupled to hinge member40as explained above and rotatable about an axis of rotation defined by center point P1, for example. Additionally, in various embodiments a distal surface15dof core15may be a curved surface defined (in part or in total) by a second circle having a center point at P1and a radius R1. The proximal surface15pof core15may also be a curved surface defined (in part or in total) by a segment of a circle having a radius R2and a center point P2. In the example embodiment, P2is located a distance D1above point P1and radius R2is greater than radius R1. Additionally, the proximal surface15pof core15is offset a distance D2from the proximal most face of the superior endplate10. In the example embodiment, center point P2is vertically above center point P1however, in other embodiments, center point P2may be offset by a greater amount or even a lesser amount than illustrated. In some examples, P2may not be aligned vertically above P1. In various embodiments, R1may be about 7-9 mm+/−about 1 mm and R2may be about 8-10 mm+/−about 1 mm although these numbers may be modified in some embodiments having a larger or smaller footprint. In various embodiments D1is about 0.25 mm to about 1.0 mm and D2is about 0.25 mm to about 1.25 mm. In at least one embodiment, D1is about 0.75 mm and D2is about 0.8 mm and R2is about 9.2 mm.

The above explained geometrical relationship between the offset center points P1and P2and R1and R2may have several advantages in terms of operability and functionality. At least one advantage is that the superior endplate10may have a natural tendency to apply a force against the engagement surface54of locking screw50such that locking screw50may function similar to a wedge preventing implant100from fully collapsing. Another advantage is that a biasing force may be applied that naturally urges the superior endplate10and inferior endplate20into an expanded position which may assist with expanding the implant100when positioned between a superior vertebrae and an inferior vertebrae, for example. For example still, an end user such as a surgeon may expand implant100and the offset arrangement explained above may facilitate the function of keeping implant100lordosed at the chosen angle.

FIG.13Ais a perspective view of a first expandable implant,FIG.13Bis a perspective view of a second expandable implant,FIG.14Ais a perspective view of a third expandable implant,FIG.14Bis a perspective view of a fourth expandable implant, andFIG.15is a perspective view of a fifth expandable implant. In the series of illustrations it is shown that various embodiments in accordance with the principles of this disclosure may be variously sized depending on the particular location in a human body and the particular patient specific human anatomy. For example,FIG.13Aillustrates a first expandable implant100having a first height H1or thickness between the superior endplate10and inferior endplate20,FIG.13Billustrates a second expandable implant100having a second height H2or thickness,FIG.14Aillustrates a third expandable implant100having a third height H3or thickness,FIG.14Billustrates a fourth expandable implant100having a fourth height H4or thickness, andFIG.15illustrates a fifth expandable implant100having a fifth height H5or thickness. In at least some embodiments, H1may be about 5 mm, H2may be about 6 mm, H3may be about 7 mm, H4may be about 8 mm, H5may about 9 mm, for example. In various embodiments, an angle of inclination between the superior endplate10and inferior endplate20may be about 4 degrees to about 15 degrees in an expanded configuration, e.g., an angled and/or inclined configuration.

FIG.16is a side view of an expandable implant100in the expanded configuration. In an expanded position, a distance D3between the superior endplate10and inferior endplate20at the proximal end100P may be relatively greater than in the closed configuration, for example. Additionally, an angle of inclination α may be relatively greater in an expanded position than in the closed configuration, for example. In this embodiment, implant100may have a height H1corresponding toFIG.13Aand be about 5 mm in a closed configuration. In the illustrated expanded configuration ofFIG.16, D3may be about 8 mm to 9 mm and α may be about 10 degrees to about 20 degrees. In at least one embodiment, D3may be 8 mm in a fully expanded position and α may be about 15 degrees, for example.

FIG.17is a side view of an expandable implant100showing a bone screw trajectory99. In the example embodiment, it is shown that a centered bone screw trajectory99of bone screw97is at an angle β with respect to a plane98that crosses through a center of the implant from a first lateral side to a second lateral side, for example. Additionally, the bone screw trajectory99may be varied+/−by a degree γ, for example. In various embodiments, β may be about 30 degrees to about 50 degrees and γ may be about 2 degrees to about 10 degrees. In the example embodiment, β may be about 40 degrees and γ may be about 5 degrees.

FIG.18is a front view of an expandable implant showing an area A1andFIG.19is a front view of an enlarged area A1ofFIG.18. In the example embodiment, bone screw97is in a position extending through bone screw aperture11where it cannot backout due to bone screw retention mechanism11a.The bone screw retention mechanism11aincludes an inclined surface11csuch that when bone screw97is being installed, an underside of the head portion of bone screw97directly contacts the inclined surface11cthereby pushing the bone screw retention mechanism11alaterally outward and away from bone screw aperture11, for example. Thereafter, when bone screw97is installed and the head portion of bone screw97is beneath inclined surface11cthe bone screw retention mechanism may flex back towards bone screw aperture11such that it will prevent bone screw97from backing out, e.g., a blocking surface of bone screw retention mechanism11amay contact an upper surface of the head portion of bone screw97. In the example embodiment, bone screw retention mechanism11acomprises flexible arm (or spring tab) having an inclined surface11c(or ramp) that is disposed on a lateral end of implant100adjacent bone screw aperture11.

Referring generally toFIGS.20-24an inserter200for use with disclosed expandable implants100is illustrated. Inserter200may extend in a longitudinal direction from a proximal end200pto a distal end200d,for example. Inserter200may include a pair of handles230, a handle lock202, and mounting arms210for securely coupling to mounting tangs19,29of implant100, for example. Inserter200may further include a tightening knob211that is connected to a drive shaft220having a drive end221. Drive end221may have a size and shape generally corresponding to a size and shape of the various drive features of locking screw50, for example the internal threaded surface52, first drive feature53a,and/or second drive feature53b.In the example embodiment shown inFIG.24, drive end221includes an end portion having an outside threaded surface with a corresponding size and shape to the internal threaded surface52of locking screw50. In various embodiments, tightening knob211may rotate drive shaft220and drive end221to engage drive end221with locking screw50and pull implant100towards inserter tool200such that mounting tangs19,29are securely nested within corresponding channels of mounting arms210. Additionally, an end user may rotate inserter200thereby translating a rotational force through drive end221to locking screw50, e.g., via first drive feature53a,and/or second drive feature53b.

As seen best inFIGS.23A and23B, inserter200may include a pair of handles230, a stationary arm252, a primary pivoting arm250, and a secondary pivoting arm251. For example, to expand implant100an end user may toggle handle lock202to an unlocked position and push down on thumb indentation231of the handle230that is connected to the primary pivoting arm250and secondary pivoting arm251. In doing so, primary pivoting arm250may pivot with respect to medial pivot point240and secondary pivoting arm251may pivot with respect to distal pivot point245, for example. The path of travel of secondary pivoting arm251may lift up on the corresponding mounting tang19or29and cause the superior endplate10and inferior endplate20to separate from one another at the proximal end, for example. In doing so, an end user can lordose implant100to a desired angle. For example, as seen best inFIG.24, secondary pivoting arm251has lifted up on mounting tang19, which is nested in a corresponding channel of mounting arm210.

Once implant100is lordosed to a desired configuration, an end user may rotate drive shaft220and drive end221to tighten locking screw50as explained previously. After locking screw50is relatively tight, the end user may continue to apply a rotational force to locking screw50until a proximal portion comprising the cylindrical part having an internal threaded surface52, and the first drive feature53abreaks off at breakoff location55. For example, once locking screw50is tightened to a designed torque, the locking screw50may shear off as explained previously. At least one advantage of utilizing the locking screw50, is that it may prevent over tightening which can cause deformation to implant100. As shown inFIG.25, implant100has been expanded to a desired position and/or lordotic angle. Additionally, locking screw50has locked the relative position of the superior endplate10with respect to the inferior endplate20and the proximal portion of locking screw50has been broken off as explained above.

FIGS.26and27are various views of a surgical instrument300for use with disclosed expandable implants100. In some embodiments, surgical instrument300may be referred to as a breakoff instrument and may be used to breakoff the mounting tangs19,29of implant100. In the example embodiment, surgical instrument300comprises a first instrument310and a second instrument320. First instrument310may extend in a longitudinal direction from handle312towards gripping end311. Similarly, second instrument320may extend in a longitudinal direction from handle322to gripping end321. Gripping ends311,321may comprise a channel having a size and shape generally corresponding to mounting tangs19,29. For example, as seen best inFIG.27, the mounting tangs19,29may be insert inside of the corresponding channels of gripping ends311,321. After the mounting tangs19,29are nested within gripping ends311,321an end user may push laterally outward and/or inward against handles312,322to breakoff the corresponding mounting tang19,29. For example, as shown inFIG.28expandable implant100is in an expanded and lordosed configuration and the proximal portion of locking screw50and tangs19,29have been broken off.

FIG.29is a reference drawing showing the human spine of which various disclosed implant embodiments may be installed in.FIG.30is a reference drawing showing various planes and reference directions of which the various disclosed implant embodiments may move in or act in with reference to a patient1.

Referring generally toFIGS.31-37a second implant400embodiment is disclosed. Implant400may include the same, similar, and/or substantially the same components and functionality as explained above with respect to implant100. Accordingly, duplicative description will be omitted. It shall be understood that various components and functionality of implant100are readily combinable with implant400and vice versa unless the context clearly indicates otherwise.

FIG.31is a perspective view of a second implant400embodiment. In this embodiment, implant400extends in a proximal-to-distal direction between a proximal end400P and a distal end400D and extends in a width-wise direction between a first lateral end400L and a second lateral end400L. Additionally, implant400includes a superior endplate410and an inferior endplate420having substantially similar features and functionality as explained above with respect to superior endplate10and inferior endplate20of implant100, for example. However, in this embodiment, superior endplate410may include a first griping protrusion419extending in a proximal direction from the proximal end400P of the superior endplate410. Similarly, inferior endplate420may include a second griping protrusion429extending in a proximal direction from the proximal end400P of the inferior endplate420. In this embodiment, a size and shape of first gripping protrusion419is substantially the same as a size and shape of the second gripping protrusion429. However, in other embodiments the first and second gripping protrusions419,429may be differently sized and shaped. In this embodiment, and in the closed position, each gripping protrusion419,429is disposed at approximately the same distance from an axis of rotation of breakoff set screw450. In this embodiment, gripping protrusions419,429may replace the need for the tangs19,29of implant100, for example. However, the concepts of utilizing breakoff tangs19,29and gripping protrusions419,429are not necessarily mutually exclusive and attributes of one may be combined and/or modified in view of the other.

In various embodiments, gripping protrusions419,429may include various types of contouring to facilitate grasping of gripping protrusions419,429with a corresponding inserter, for example surface indentations, surface outdents, channeling, etc. In the example embodiment, gripping protrusion419comprises a superior gripping surface419A including an indented portion and an outdented chamfered portion at a proximal most end thereof, for example. Additionally, gripping protrusion419comprises an inferior gripping surface419B including an indented portion and an outdented chamfered portion at a proximal most end thereof, for example. Likewise, gripping protrusion429comprises a superior gripping surface429A including an indented portion and an outdented chamfered portion at a proximal most end thereof, for example. Additionally, gripping protrusion429comprises an inferior gripping surface429B including an indented portion and an outdented chamfered portion at a proximal most end thereof, for example. In this way, gripping protrusions419and429are shaped like dovetails and a corresponding inserter tool may comprise a corresponding shaped dovetail groove which may grasp onto and/or slip over gripping protrusions419and429(not illustrated).

Referring generally toFIGS.32,33, and34various exploded parts views of implant400are illustrated.FIG.32is a first perspective exploded parts view of implant400,FIG.33is a second perspective exploded parts view of implant400, andFIG.34is a side exploded parts view of implant400. In the example embodiment, the superior and inferior endplates410,420of implant400may be hingedly coupled together by hinge member440and arcuate channel412having similar attributes as explained above with respect to hinge member40and channel12of implant100, for example. Additionally, superior endplate410may also include a core415having an aperture415A and inferior endplate420may include a core425having a threaded aperture425A having similar attributes to core15and core25as explained above with respect to implant100, for example. In the example embodiment, implant400utilizes a breakoff screw450for locking of a position of the superior and inferior endplate410,420. Breakoff screw450may include an external thread pattern451on an outside circumferential surface thereof, for example. The external thread pattern451of breakoff screw450may have a size and shape generally corresponding to the threaded aperture425aof core425of the inferior endplate420, for example. In various embodiments, an engagement surface454may be disposed adjacent and proximal of external thread pattern451. In the example embodiment, engagement surface454is shaped like a washer and is directly connected to breakoff screw450. However, in other embodiments, engagement surface454may be a washer or separated element, for example. In some embodiments, engagement surface454may be conically shaped. In the example embodiment, engagement surface454may include a relatively planar and/or flat distal surface and/or proximal surface.

In various embodiments, a proximal end of breakoff screw450may include a first flexible tang452A and a second flexible tang452B defining a discontinuous cylindrical shaped aperture452therebetween. Additionally, the first flexible tang452A and second flexible tang452B may each include an outdent at a proximal end thereof that is shaped like a segment of an annular ring. In the example embodiment, the first flexible tang452A may flex inward towards the second flexible tang452B under loading and vice versa due to the gap between them. At least one advantage of this configuration is that it may facilitate securing breakoff screw450to a corresponding drive tool (not illustrated) and the retention of the broken off part. For example, a drive tool may comprise a drive end having a female cavity with a corresponding size and shape to the drive features453A,453B. In various embodiments, the cavity may include a pair of indentations corresponding in size and shape to the outdents of flexible tangs452A and452B, for example. In use, an end user may align the flexible tangs452A,452B with the cavity, push down against the flexible tangs452A,452B which may cause them to flex inward towards each other such that they may slide within the cavity until the outdents of flexible tangs45A and452B are seated within the corresponding indents of the drive tool. Thereafter, an end user may continue to rotate and or tighten breakoff screw450. In this way, after a proximal portion of breakoff screw450is broken off it may remain retained by the inserter due to the flexible tangs452A and452B being seated within the corresponding indents.

In some embodiments, aperture452may be understood as a cylindrical protrusion extending in a proximal direction and having a first slit and a second slit extending along the length thereof such that the cyldrical protrusion is compressible. In the example embodiment, a first drive feature453A and a second drive feature453B may be disposed adjacent to and distally with respect to a proximal most end of breakoff screw450. Additionally, first and second drive features453A,453B may be disposed proximally with respect to engagement surface454. In various embodiments, a breakoff location may be positioned between and/or adjacent to drive features453A,453B, which will be explained in further detail below. In the example embodiment, drive features453A,453B take a hexalobular shape, although various other shapes such as hexaganol, polygonal, torx, etc. are also contemplated. In some embodiments, a surgical drive tool having a corresponding socket may be coupled to drive features453A and/or453B to cause rotation of breakoff screw450. Similarly as explained above with respect to locking screw50, once breakoff screw450has been sufficiently tightened a proximal portion may breakoff and/or shear off while the distal portion may remain coupled to implant400locking a relative orientation of superior endplate410and inferior endplate420in place.

As seen best inFIGS.35-37, breakoff screw450may extend in a longitudinal direction along a longitudinal axis L-A that is coaxially aligned with breakoff screw450.FIG.35is a first side view of breakoff screw450in which the superior surface452A and inferior surface452B of discontinuous aperture452are visible.FIG.36is a second side view of a breakoff screw450that is rotated about 90 degrees with respect toFIG.35in which only the superior surface452A is visible. With reference toFIG.37, in various embodiments, breakoff location455may comprise a recessed fracture surface F-S that is inset with respect to a leading edge (proximal most edge) of drive feature453A. At least one advantage of the recessed fracture surface may be that delicate tissue is prevented and/or suppressed from coming into contact with relatively sharp ends of the fracture surface. In the example illustration, a relative location of the recessed fracture surface is represented by dashed lines F-S. In the example embodiment, breakoff location455may be considered as the boundary between a proximal portion450A and a distal portion450B of breakoff screw450, for example. In this embodiment, the boundary between drive features453A and453B comprises a necked down portion458extending from a distal end of drive feature453A to an inset portion of drive feature453B that is inset with respect to an outermost and/or proximal most surface of drive feature453B thereby defining a portion of breakoff set screw450having a minimum cross sectional diameter. Accordingly, when breakoff screw450is sufficiently tightened within threaded aperture425A of core425such that the breakoff location455experiences a sufficient torque the proximal portion450A may breakoff from the distal portion450B. For example, when a sufficient rotational force is applied to the proximal end of breakoff screw450while a distal end of breakoff screw450is stationary, i.e., when breakoff screw450is secured in a locked position and a continued rotational force (torque) is applied to the proximal end of breakoff screw450the drive feature453aand cylindrical end having the discontinuous aperture452may breakoff. For further explanation in the similar context of implant100, seeFIGS.10and11and the corresponding discussion thereof.

Referring toFIGS.38-42an example swaging process is performed to a distal most end of breakoff screw450.FIG.38is a perspective view of a swaging fixture500, andFIG.39is a cross section view of a swage mandrel and a distal end450D of a breakoff screw450before the commencement of a swage process.FIG.40is a cross section view showing a result of a swage process, andFIG.41is an enlarged view of region S-W ofFIG.40. In the example embodiment, swaging fixture500comprises a swaging ram501and a swaging mandrel503that are supported by the base of the apparatus. The swaging mandrel503may include an outdent that corresponds to and is slightly larger than the distal most indent498of breakoff screw450, for example. As seen in region S-W ofFIG.40, when swaging mandrel503is advanced into the distal most indent498a flared out portion499(swaged portion) is formed at a distal most end of breakoff screw450. An example advantage of a swaged end may be that it facilitates retention of the breakoff screw450such that it serves as a stopping structure preventing breakoff screw450from backing out of implant100.

It shall be understood that although breakoff screw450is explained concurrently with implant400and in the context of an intervertebral implant, the concepts of breakoff screw450may be applied to other embodiments used for alternate purposes, for example for use in a pedicle screw to insert in a tulip to tighten down a rod. It should be understood that various aspects disclosed herein may be combined in different combinations than the combinations specifically presented in the description and accompanying drawings. For example, features, functionality, and components from one embodiment may be combined with another embodiment and vice versa unless the context clearly indicates otherwise. Similarly, features, functionality, and components may be omitted unless the context clearly indicates otherwise. It should also be understood that, depending on the example, certain acts or events of any of the processes or methods described herein may be performed in a different sequence, may be added, merged, or left out altogether (e.g., all described acts or events may not be necessary to carry out the techniques).

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