Implant with bone screw retention

An implant includes a plurality of anchoring members and an interbody device. The interbody device includes a front, a rear, a first lateral side, a second lateral side, a central cavity, and a plurality of bores each configured to receive the plurality of anchoring members. The interbody device further includes a porous portion and a solid portion, the solid portion having a higher density than the porous portion. The solid portion substantially surrounds the porous portion on the lateral outer portions of the front, rear, first lateral side, and second lateral side.

BACKGROUND

The present disclosure generally relates to methods and devices for orthopedic surgery. More specifically, the present disclosure relates to the present disclosure relates to methods and devices for orthopedic surgery of the spine and, particularly, to methods and devices for anterior lumbar interbody fusion (ALIF). Many people contend with spine issues as a result of age, disease, and trauma, as well as congenital and acquired complications and conditions. While some of these issues can be alleviated without surgery, other issues necessitate surgery. Spinal fusion may be recommended for conditions such as spondylolistheses, degenerative disc disease, or recurrent disc herniation, and is designed to create solid bone between adjacent vertebrae, thereby eliminating any movement between the bones. A spinal fusion uses an implant or device known as an interbody cage or spacer along with bone graft and/or bone graft substitute that is inserted into the disc space between adjacent vertebrae from one side of the spine. Typically, additional surgical hardware (implants) such as pedicle screws and rods or plates are attached to the back of the vertebrae. As the bone graft heals, it fuses the adjacent vertebrae to form one long vertebra.

A fusion of the lumbar region of the spine (a lumbar fusion) may be accomplished using several techniques. Once such technique is known as an anterior lumbar interbody fusion or ALIF. ALIF spine surgery is performed through the anterior aspect of the spine and provides stabilization of the spine. In an ALIF, the disc space is fused by approaching the spine through the abdomen. In one approach, an incision is made on the left side of the abdomen and the abdominal muscles are retracted to the side. Since the anterior abdominal muscle in the midline (the rectus abdominis) runs vertically, it does not need to be cut and easily retracts to the side. The abdominal contents lay inside a large sack (peritoneum) that can also be retracted, thus allowing the spine surgeon access to the front of the spine without actually entering the abdomen.

After the blood vessels have been moved aside, the disc material is removed and bone graft typically with an anterior interbody cage is inserted. The ALIF approach leaves both the back muscles and nerves remain undisturbed. Additionally, placing the bone graft in the front of the spine places it in compression, and bone compression tends to fuse better. Moreover, a much larger implant can be inserted through an anterior approach, providing for better initial stability of the fusion construct. When an interbody cage is used, it is important that it is securely anchored.

However, there is room for improvement over current ALIF implants, instruments, and/or surgical procedures.

In view of the above, it is an object of the present disclosure to provide an improved ALIF implant, an instrument for implanting the improved ALIF, and/or a surgical procedure for the implantation.

SUMMARY

ALIF spine implants (ALIF implants), ALIF installation instruments/tools, and ALIF procedures using the ALIF implants and ALIF installation instruments for an anterior lumbar interbody fusion (ALIF) surgical procedure are provided. The ALIF implants are characterized by an ALIF cage and anchoring members. The ALIF installation instruments are characterized by a shaft having an inserter on one end that receives and holds an ALIF cage and anchoring members. The installation instrument allows insertion of the ALIF cage into a vertebral space, the anchoring members to be received in the ALIF cage, and then into vertebral bone.

Each ALIF cage is characterized by a porous body that may be, but not necessarily, 3-D printed, having a central cavity, an end configured to accept a plurality of anchoring members and direct a portion of the anchoring members up and out of the cavity, a cutout configured to receive an anchoring member retention component, and an anchoring member retention component.

The anchoring member retention component may be a set screw or plate. The plate may be a separate piece or may be pivotally attached to the ALIF cage via a hinge or other pivot structure.

The anchoring members may be curved anchoring barbs or linear anchoring screws.

Upper (superior) surfaces of the body of the ALIF implant and lower (inferior) surfaces of the body of the ALIF implant may, but not necessarily, each have serrations, teeth or the like.

A form of the ALIF instrument is characterized by a hollow shaft extending from a handle, the hollow shaft having a distal end that is attached to an inserter. The inserter is configured to receive and hold the ALIF cage, and to receive and direct anchoring members into the ALIF cage. As such, the inserter has curved channels, one curved channel for each anchoring member along with a leaf spring that retains the anchoring member within its curved channel. An impactor is used to urge or push the anchoring members from the inserter into the ALIF cage, then into the vertebral bone.

In the case of the ALIF cage having a pivoting anchoring member retention component, the inserter has a lateral channel that receives the pivoted anchoring member retention component. Once the ALIF cage is disengaged from the inserter, the anchoring member retention component is pivoted to cover the inserted anchoring members. This inhibits, if not prevents, anchoring member back-out.

In further embodiments, an implant is disclosed. The implant includes a plurality of anchoring members and an interbody device having a front, a rear, a first lateral side, a second lateral side, a central cavity, and a plurality of bores each configured to receive one of the plurality of anchoring members. The interbody device includes a porous portion and a solid portion. The solid portion has a higher density than the porous portion. The solid portion substantially surrounds the porous portion on the lateral outer portions of the front, rear, first lateral side, and second lateral side.

In further embodiments, an implant is disclosed. The implant includes a plurality of anchoring members and an interbody device having a front, a rear, a first lateral side, a second lateral side, a central cavity, and a plurality of bores each configured to receive one of the plurality of anchoring members. The interbody device includes a porous portion and a solid portion, the solid portion having a higher density than the porous portion. The first lateral side includes a first lateral window extending through the solid portion and the second lateral side includes a second lateral window extending through the solid portion.

In further embodiments, an implant is disclosed. The implant includes an anchor member and an implant body comprising an inner lateral peripheral portion comprising a porous material and defining a central cavity, an outer lateral peripheral portion comprising a solid material and surrounding the inner lateral peripheral portion, and at least one bore configured to receive the anchor member to secure the implant to adjacent bone. The implant body is formed as a single integral piece.

In further embodiments, an implant is disclosed. The implant includes an anchoring member and an implant body. The implant body includes at least one bore configured to receive the anchor member to secure the implant to an adjacent bone. The implant further includes an installation tool interface, and an installation tool. The installation tool includes an interface body configured receive the implant body, wherein the interface body can controllably attach the implant body to the installation tool, a retention member configured to selectively release the implant body, and a drive member configured to drive the anchoring member into the adjacent bone while the installation tool is attached to the implant body.

Corresponding reference characters indicate corresponding parts throughout the several views. Although the drawings represent embodiments of the disclosure, the drawings are not necessarily to scale and certain features may be exaggerated in order to better illustrate and explain the principles of the present disclosure. The exemplifications set out herein illustrate several embodiments, but the exemplifications are not to be construed as limiting the scope of the disclosure in any manner.

DETAILED DESCRIPTION

Referring toFIGS.1-9, there is depicted a form of an anterior lumbar interbody fusion (ALIF) implant (ALIF spine implant or ALIF implant), generally designated10, fashioned in accordance with the present principles. The ALIF implant10is made from a biocompatible material such as, but not limited to, PEEK, PETE, other plastic or polymer, titanium, stainless steel, an alloy of titanium or stainless steel, or otherwise. The ALIF implant may, but not necessarily, be 3-D printed. The ALIF spine implant (spine implant)10has a porous cage or interbody device12, two or more anchoring members14, each anchoring member14fashioned as a barb, blade, shim or the like (herein “barb”)14, and a set screw (anchoring member)13.

The set screw13is generally cylindrical with external threads. A socket15is provided in the top of the set screw13that is configured to receive a tool (not shown) for installing the set screw into the porous cage12. As seen inFIGS.2-4, the set screw13is used to keep the barbs14from backing out of the porous cage12as well as to compress the operative level after the barbs14are impacted into vertebral bone by forcing the barbs14to pivot toward each other, resulting in segmental compression.FIG.2shows the barbs14being received into the porous cage12with the set screw13ready for insertion.FIG.3shows the barbs14fully inserted into the porous cage12with the set screw13also received in the porous cage12, but before compression of the barbs14. When the set screw13is fully seated into the porous cage12(FIG.4), the set screw13bottoms out against the shoulders29of the barbs14to compress against and pivot the barbs14.FIG.1shows the barbs14fully received and compressed into the porous cage12by the set screw13.

The barb14is particularly shown inFIGS.7-9and is characterized by a curved body16having a head21at a first end, and a tip17at a second end, the nomenclature first and second being arbitrary. The tip17is generally “shovel-shaped” to provide easy piercing and/or penetration into vertebral bone. Other configurations may be used. The body16has an angled cross-section to increase stiffness and resistance to flexion-extension movement of the spine when implanted. The head21is at the end of a neck20that extends from one side of the curved body16, and include a threaded bore22. The threaded bore22allows for use of an extractor instrument (not shown) to withdraw the barb from the porous cage12if needed. The barb further includes a shoulder19at the first end that is axially offset from the head21. As explained further below, when the barbs14are received in the porous cage12, the set screw13bottoms out against the shoulders19.

As most particularly seen inFIGS.1,5and6, the ALIF implant10is characterized by a generally porous body24fashioned generally as a rectangular wedge having an upper (superior) surface25, a lower (inferior) surface26opposite to the upper surface25, a first lateral side29, a second lateral side30that is opposite to and identical with the first lateral side29, a first end or front27, and a second end or rear28opposite to the front27, the nomenclature “first,” “second,” “front,” and “rear” being arbitrary. The body24also has a cavity31that extends from the upper surface25to the lower surface26. The cavity31is adapted or configured to receive bone graft/bone graft material such as is known in the art.

Extending along the upper surface25adjacent the first lateral side29(edge) is a section of serrations, teeth, or the like (collectively, serrations)32, while extending along the upper surface25adjacent the second lateral side30(edge) is a second section of serrations, teeth, or the like (collectively, serrations)33, the nomenclature “first” and “second” being arbitrary. The serrations32,33provide gripping of the cage12to a superior vertebra/vertebral bone when implanted. In like manner, extending along the lower surface26adjacent the first lateral side29(edge) is a third section of serrations, teeth, or the like (collectively, serrations)33, while extending along the lower surface26adjacent the second lateral side30is a fourth section of serrations, teeth, or the like (collectively, serrations)35, the nomenclature “third” and “fourth” being arbitrary. The serrations33,35provide gripping of the superior end of an inferior vertebra/vertebral bone when implanted.

The rear28of the body24defines a nose or arch having a downwardly angled or sloped upper (superior) surface, an upwardly angled or sloped lower (inferior) surface opposite to the downwardly angled upper surface, a first rounded side, and a second rounded side opposite to the first rounded side, the nomenclature “first” and “second” being arbitrary. The front27of the body24is generally planar with a large threaded bore44that extends therein a distance or to the cavity31. The threaded bore44receives the set screw13. A first elongated slot41runs from the front27around to and along a portion of the first lateral side29, while a second elongated slot42runs from the front27around to and along the second lateral side30, the nomenclature “first” and “second” being arbitrary. The first elongated slot41is adapted/configured to receive a first prong of an installation tool (not seen), while the second elongated slot42is adapted/configured to receive a second prong of the installation tool (not seen) opposite the first prong, the nomenclature “first” and “second’ being arbitrary.

The front27also has a first curved slot45extending from one side of the threaded bore44and a second curved slot46extending from another side of the threaded bore44, the curved slots45,46opposite one another. The first curved slot45has a curvature that matches the profile of the barb14and which is angled such that the tip17and a portion of the first end thereof extends downwardly out of the cavity31of the body24of the porous cage12when the barb14is fully inserted therein. The second curved slot46has a curvature that matches the profile of the barb14and which is angled such that the tip17and a portion of the first end thereof extends upwardly out of the cavity31of the body24of the porous cage12when the barb14is fully inserted therein.

Referring toFIGS.10-13, there is depicted another form of an anterior lumbar interbody fusion (ALIF) implant (ALIF spine implant or ALIF implant), generally designated100, fashioned in accordance with the present principles. The ALIF implant100is made from a biocompatible material such as, but not limited to, PEEK, PETE, other plastic or polymer, titanium, stainless steel, an alloy of titanium or stainless steel, or otherwise. The ALIF implant may be 3-D printed. The ALIF spine implant (spine implant)100has a porous cage or interbody device112, and three anchoring members50, each anchoring member50fashioned as a screw.

The screw50is characterized by a linear, externally threaded shaft53. In one embodiment, the externally threaded shaft53has a constant diameter, while in other embodiments, the externally threaded shaft53has a variable diameter. The screw50has a head52at a first end, and a tip54at a second end, the nomenclature first and second being arbitrary. In one embodiment, the tip54is pointed. The head51further includes a socket52in its upper surface that is configured to receive an installation tool (not shown).

The porous cage112of the spine implant100has the same configuration as the spine implant10except for its front, which is explained below. The numbering of features, components and the like of the porous cage112adds a “100” to the numbering of those features components and the like of the porous cage112that are the same as the features, components and the like of the porous cage12. As such, the description of these features, components and the like of the porous cage112will not be discussed, as they have been discussed above regarding the porous cage12.

The front127of the porous cage112includes a channel145that extends generally from the second lateral side140to the first lateral side139. A first angled screw bore146is provided in the front127of the body124proximate the second lateral side140. The bore146extends from the front127to the cavity131and is sized to allow the threaded shaft53of the screw50to extend therethrough and into the cavity131, the front of the bore146defining a pocket sized to capture the screw head51. The bore146is angled downwardly such that the threaded shaft53and thus the tip54of the screw50extends downwardly out of the cavity131. A second angled screw bore147is provided in the front127of the body124proximate a middle of the front127. The bore147extends from the front127to the cavity131and is sized to allow the threaded shaft53of the screw50to extend therethrough and into the cavity131, the front of the bore147defining a pocket sized to capture the screw head51. The bore147is angled upwardly such that the threaded shaft53and thus the tip54of the screw50extends upwardly out of the cavity131. A third angled screw bore148is provided in the front127of the body124proximate the first lateral side139. The bore148extends from the front127to the cavity131and is sized to allow the threaded shaft53of the screw50to extend therethrough and into the cavity131, the front of the bore148defining a pocket sized to capture the screw head51. The bore148is angled downwardly such that the threaded shaft53and thus the tip54of the screw50extends downwardly out of the cavity131. It should be appreciated that the angle of the bores may be changed as desired. The front127also includes a threaded hole149in the channel145adjacent the second lateral side140. The threaded hole149is sized to accept a machine screw153of an anchoring member retention component150.

The anchoring member retention component150is in the form of a plate that is pivotally connected to the front127of the porous cage112via a hinge151, the hinge151is situated adjacent the first lateral side139. The hinge151includes a pivot pin that is received in the body124and through the end of the plate150. In one embodiment, the plate150is sized for reception in the channel145of the front127with a friction fit to prevent “flopping.” The plate (lid, or latch)150may prevent back-out of the bone screws50. In one embodiment the plate150prevents back-out by making contact with the head of the bone screw50once the plate150is secured to the cage112. The plate150has a boss152on its end opposite the hinge151that permanently holds the machine screw153but allows its rotation. The machine screw153is receivable in the threaded bore149in order to secure the plate150to the body124. The plate150has a generally smooth outer surface154.

In order to aid in anchoring member back-out prevention, an inside surface155of the plate has three (3) protrusions or projections156,157,158corresponding in number to and position of the angled bores146,147,148of the front127. Each projection156,157,158is generally triangular shaped in order to fit into the pocket formed by the bore156,157,158. Once the plate150is closed, the projection156of the plate150is received in the bore pocket146, the projection157of the plate150is received in the bore pocket147, and the projection158of the plate is received in the bore pocket148.

Referring toFIG.13, the exit diameter of the openings in the cage can either allow or disallow bone screws to angulate in the sagittal plane. Variable angle fasteners are shown. Moreover, the protrusions156,157,158of the plate150make contact with the heads of the bone screws50once the latch is secure. The protrusions156,157,158of the plate150may also be configured to generate segmental compression by forcing anchoring members (bone screws) to pivot toward the coronal mid-plate of the disc space when the machine screw153is tightened.

Referring toFIGS.14-17there is depicted another form of an anterior lumbar interbody fusion (ALIF) implant (ALIF spine implant or ALIF implant), generally designated100athat is the same as the ALIF spine implant100except the spine implant100auses three (3) barbs160rather than three (3) bone screws50. The porous cage112of the spine implant100ahas the same configuration as the spine implant100. As such, the description of these features, components and the like of the spine implant100is applicable to the spine implant100aand will not be discussed again.

As best seen inFIGS.16-17, the barb160is characterized by a curved shaft161having a constant diameter. The barb160has a head162at a first end, and a tip164at a second end, the nomenclature first and second being arbitrary. The tip164is may be generally chisel-shaped, but other configurations may be used. The head162includes a socket163in its upper surface that is configured to receive an installation tool (not shown). The underside168of the head162defines a shoulder that bottoms out on the cage. The head162also has a flat166on one side and another flat (not seen) on the other side. Four grooves (or similar feature)169,170,171,172are provided on the outside surface of the barb161. In one embodiment, the grooves169,170,171,172extend from the tip164to the head162. The grooves reduce the cross-sectional area of the barbs thereby reducing the amount of material (bone) that has to be displaced in order for the barbs to be impacted into the vertebral bone.

Referring toFIGS.24-25there is depicted another form of an anterior lumbar interbody fusion (ALIF) implant (ALIF spine implant or ALIF implant), generally designated200that is the same as the ALIF spine implants100and100aexcept the spine implant200uses two (2) screws50and one (1) barb160. Other combinations of screws50and barbs160can be used. The spine implant200has the same configuration as the spine implants100and100awith the exception of the front227and the anchoring member retention component250. The numbering of features, components and the like of the spine implant200adds a “200” to the numbering of those features components and the like thereof that are the same as the features, components and the like of the spine implants100,100aexcept as noted. As such, the description of these features, components and the like will not be discussed, as they have been discussed above.

The channel245of the front227includes an upper slot258and a lower slot259proximate the first lateral side239, and an upper slot260and a lower slot261proximate the second lateral side. The anchoring member retention component250is in the form of a plate that is friction or press-fit into the front127of the porous cage112. The plate250includes an upper hook253and a lower hook254on a first end of the plate250(corresponding to the first lateral side239of the cage212), and an upper hook255and a lower hook256on a second end of the plate250(corresponding to the second lateral side240of the cage212. The upper hook253is received in the upper slot258, the lower hook254is received in the lower slot259, the upper hook255is received in the upper slot260, and the lower hook256is received in the lower slot261. Moreover, the first end of the plate250has a resilient clip and slot structure251, while the second end of the plate250has a second resilient clip and slot structure252. The clip and slot structures251,252accept mating features on a plate-inserter instrument (not shown) that, when engaged, deflects the branches of the clip and slot structures251,252away from each other allowing the plate to engage the mating recesses on the front127. When the plate inserter instrument is detached, the branches spring back toward each other. The purpose of the plate or lid250is to prevent back-out of the anchoring members.

Referring toFIGS.18-23, there is shown an exemplary instrument or tool300for installing/implanting the ALIF implants100,100a, and200. The instrument300includes a shaft301with a handle302at one end, a neck303at the other end, and an inserter304connected to the neck303. The neck303has a first prong305on one side, and a second prong306on another, opposite side. A proximal end of the inserter304has a first notch307on one side corresponding to the first prong305and shaped to receive same, and a second notch308on another, opposite side corresponding to the second prong306and shaped to receive same. The neck303and/or the shaft301has one or more pushers (of which a single pusher319is shown inFIGS.20-22) for urging a barb160(anchoring member) from the inserter, into the cage body124, then into vertebral bone (not shown). As seen inFIG.23, a channel322is provided in a lateral side of the inserter304for receipt of the anchoring member retention component (e.g. plate150), which holds the plate150in an open position during cage implantation. As seen in the example embodiment shown inFIG.19, the inserter304has a threaded hole315that is used to attach the inserter to the cage, the shaft having a shoulder that bottoms out on inserter features once threaded onto the cage and is permanently detained within the inserter. The inserter304also has three (3) leaf springs310,311,312or the like corresponding in number to the number of curved channels for the anchoring members (e.g. barbs). Each leaf spring interacts with the serrations165of the barb160to retain the barb160through ratcheting.

The inserter304has three curved channels316,317, and318corresponding in number to the number of anchoring members (e.g. barbs) used by the spine implant, here being three (3).FIGS.20-22are a three sequence illustration of how a barb160is installed into the spine implant and vertebral bone. InFIG.20, a barb160is received in the curved channel316that is arced to direct the barb160upwardly out of the cavity of the cage. InFIG.21, a pusher or impactor319in the channel320of the instrument300begins to contact the head162of the barb160and urge the barb160into the cage. InFIG.22, the pusher319has fully urged the barb160into the cage. The other barbs160are installed in like manner.

As seen inFIGS.27and28, the interbody device412is generally a rectangular wedge having an upper (superior) surface425, a lower (inferior) surface426(seeFIG.34) opposite to the upper surface425, a first lateral side429, a second lateral side430that is opposite the first lateral side429, a first end or front427, and a second end or rear428opposite to the front427. In some embodiments, the first lateral side429and the second lateral side430are identical (e.g., mirror images of each other). The nomenclature “first,” “second,” “third,” and “rear” are arbitrary, and not meant to imply any particular orientation of the device. The interbody device412also has a cavity431that extends from the upper surface425to the lower surface426. The cavity431is configured to receive bone graft/bone graft material.

The first lateral side429has an inner surface529proximate the cavity431and an outer surface629opposite the inner surface529. Similarly, the second lateral side430has an inner surface530proximate the cavity431and an outer surface630opposite the inner surface530. The first lateral side429and the second lateral side430are discussed in greater detail below.

The rear428of the interbody device412defines a nose or arch having a downwardly angled or sloped upper (superior) surface580, an upwardly angled or sloped lower (inferior) surface582opposite to the downwardly angled upper surface580, a first rounded side584, and a second rounded side586opposite to the first rounded side584, the nomenclature “first” and “second” being arbitrary. The front427of the interbody device412has a slight curvature with two threaded bores444(seeFIG.29) that extend therein a distance or to the cavity431. The threaded bores444are configured to receive the cam screws413.

In certain embodiments, the interbody device412may also include a first tool interface702and a second tool interface704. In certain embodiments, the first tool interface702and second tool interface704may be configured to individually receive a first arm714and a second arm715, respectively, of an installation tool700. In these example embodiments, the first arm714and the second arm715may be used to secure the interbody device412to the installation tool700, as will be described further herein.

In some embodiments, the interbody device412is manufactured as one piece, although the material need not be homogenous throughout, as will be explained in further detail. For example, in one embodiment, the interbody device412will have a solid portion440made of a solid biocompatible material and a porous portion442made of a porous biocompatible material, such that the porous portion442includes a plurality of pores542. Therefore, solid portion440will have a higher density than the porous portion442.

The solid portion440of the interbody device412is shown as solid in the figures, while the porous portion442is shown with cubic pores542in the figures. It should be noted that the cubic pores542are not necessarily shown to scale or shape, but instead are simply used to indicate the porous portion442of the interbody device412. Further, while the pores542shown in the images are cubic pores542, it should be appreciated that the pores542can be a variety of different shapes, including circular, triangular, square, pentagonal, heptagonal, octagonal, decagonal, etc., or any combination thereof, including irregular shapes and/or patterns.

In certain example embodiments, the pores542utilized in the porous portion442may be hexagonal in shape due to the relatively high specific strength (i.e. force per unit area at failure divided by its density) of the pores542. While the interbody device412includes a solid portion440and a porous portion442, in one embodiment, the entire interbody device412may be manufactured as one piece and/or of a single type material (e.g., titanium). In some embodiments, the interbody device412may be manufactured using a 3-D printer that is capable of printing biocompatible material.

In an example embodiment, the porous portion442may provide certain benefits relative to other implants. First, the porous portion442, which substantially surrounds the cavity431, creates a surface roughness that enhances immediate implant stability and facilitates surface adhesion. For this reason, the inner surfaces529,530are generally porous. Second, the porous portion442mimics the structure and porosity of cancellous bone and has a stiffness similar to bone, thereby giving the implant400a more comfortable and natural feel for the patient. Third, the porous portion442reduces the density of the implant400while also enhancing the intraoperative and postoperative imaging, which is discussed further below.

As shown inFIGS.26-33, the solid portion440generally surrounds the porous portion442on the first end427, the second end428, the first lateral side429, and the second lateral side430, such that the material furthest from the cavity431on the first end427, the second end428, the first lateral side429, and the second lateral side430is generally solid material. However, in the example embodiment shown, the outer surface629of first lateral side429and the outer surface630of the second lateral side430include a window lattice433(e.g., one or more recesses, windows, etc.). The window lattice433is made up of a plurality of lateral windows434. Each lateral window434has a lateral window floor436and lateral window walls435, such that the depth of the lateral window434(herein “lateral window depth”) (i.e. the distance between the outer surface629of the first lateral side429and the lateral window floor436) is substantially equal to the length of the lateral window wall435(e.g., measured in a direction perpendicular to the lateral window floor436). In this embodiment, the solid portion440has a thickness equal to the height of the window walls435at the edge of each lateral window434. It should be noted that, for purposes of this application, the window floors436are not considered part of the outer surfaces629,630. Therefore, the outer surfaces629,630of the first lateral side429and the second lateral side430are generally solid material.

After the implant400has been installed into a patient, the window lattice433allows for visualization of the graft area within the cavity431and the porous portion442using a medical imaging device, such as an X-ray machine or a Fluoroscopy machine. By aiming the medical imaging device substantially parallel to the window walls435, a medical practitioner or other user is able to view the graft area through the window lattice433. While the porous portion442is positioned between the graft area and the medical imaging device, in some embodiments the porous structure of the porous portion442does not substantially prevent X-rays from passing through the porous portion. Therefore, the medical practitioner can use a medical imaging device to view the graft area through the window lattice433using the medical imaging device.

The window lattice433reduces the overall weight of the interbody device412while still providing sufficient structural strength. Since the solid material may be significantly stronger than the porous material, it may provide additional structural strength. Further, by utilizing a window lattice433made from solid material, the implant400will have increased structural strength while enjoying the several benefits of using a porous material.

Referring now toFIG.29, an exploded view of the implant400is shown. In this example embodiment, the anchoring members414are bone screws416.FIG.29shows an exploded view of the implant400including an interbody device412, two cam screws413, and three bone screws416.

As shown inFIGS.36and37, the bone screw416includes a linear, externally threaded shaft453. The bone screw416has a head452at a first end, and a tip454at a second end, the nomenclature first and second being arbitrary. In some embodiments, the tip454is pointed. In some embodiments, the diameter of the bone screw416gradually decreases from the head452to the tip454. The head452further includes a socket451configured to receive an installation tool. While this example embodiment shows the socket451as being a hex head socket, it should be appreciated that the socket451can be designed to receive several different types of hand tools, including a slotted screw driver, a Phillips-head screwdrivers, an Allen wrench screwdriver, a hexagonal drive, a torx drive, a Robertson drive, a tri-wing screwdriver, an Allen security driver, a torx security driver, a Pozidriv, a clutch drive, a spanner, a Schrader drive, a nut driver, a hex wrench, a node security driver, any combination of the listed driver interfaces, and any other type of driver interface.

As shown inFIGS.38-41, the cam screw413includes a linear, externally threaded shaft463. The cam screw413has a head462at a first end, and a tip464at a second end, the nomenclature first and second being arbitrary. In this example embodiment, the tip464is flat. In this example embodiment, the diameter of the shaft463remains constant throughout. The head462also includes two shoulders466positioned at opposite sides of the head462. The shoulders466extend radially from the center of the head462, such that the distance from the center of the head462to the edge of the shoulder466is greater than the radius of the threaded shaft463.

As shown inFIG.29, the first end427of the interbody device412includes a channel445that extends generally from adjacent the first lateral side429to adjacent the second lateral side430. The channel445includes a first angled screw bore446in the first end427of the interbody device412proximate the first lateral side429. The first angled screw bore446extends from the first end427to the cavity431. The first angled screw bore446is sized to allow the threaded shaft453of the bone screw416to extend therethrough and into the cavity431. The front of the first angled screw bore446defines a pocket sized countersink to capture the bone screw head452. The first angled screw bore446is angled upwardly such that the threaded shaft453and thus the tip454of the bone screw416extends upwardly out of the cavity431.

The channel445further includes a second angled screw bore447in the first end427of the interbody device412proximate a middle of the first end427. The second angled screw bore447extends from the first end427to the cavity431. The second angled screw bore447is sized to allow the threaded shaft453of the bone screw416to extend therethrough and into the cavity431. The front of the second angled screw bore447defines a pocket sized countersink to capture the bone screw head452. The second angled screw bore447is angled downwardly such that the threaded shaft453and thus the tip454of the bone screw416extends downwardly out of the cavity431.

The channel445further includes a third angled screw bore448in the first end427of the interbody device412proximate the second lateral side430. The third angled screw bore448extends from the first end427to the cavity431. The third angled screw bore448is sized to allow the threaded shaft453of the bone screw416to extend therethrough and into the cavity431. The front of the third angled screw bore448defines a pocket sized countersink to capture the bone screw head452. The third angled screw bore448is angled upwardly such that the threaded shaft453and thus the tip454of the bone screw416extends upwardly out of the cavity431.

It should be appreciated that the angle of the bores may be changed as desired. In addition, in this example embodiment, the angled screw bores allow for variable trajectory of the bone screws416. For example, in this embodiment, the first angled screw bore446and the third angled screw bore448allow a variable upwards trajectory of the bone screw416of up to forty-five degrees from the horizontal mid-plane of the interbody device412. Further, in this example embodiment, the second angled screw bore447allows a variable downward trajectory of the bone screw416of up to 45 degrees from the horizontal mid-plane of the interbody device412. In other embodiments, other trajectories may be used (e.g., 30 degrees, etc.), the trajectories relative to the horizontal mid-plane may be constant or vary between the different screw bores.

The first end427of the interbody device412also includes two threaded bores444in the channel445. The threaded bores444are configured to receive a cam screw413. In this example embodiment, the threaded bores444extend from the first end427into the solid portion440of the interbody device412. In this example embodiment, the threaded bores444do not extend into the porous portion442or into the cavity431. However, in other example embodiments, the threaded bores444may extend into the porous portion440and/or into the cavity431. Further, in this embodiment, the threaded bores444are substantially parallel to the horizontal mid plane of the interbody device412. In other embodiments, the threaded bores444may be angled up or down relative to the horizontal mid plane of the interbody device412.

Prior to surgery, the cam screws413can be pre-threaded into the threaded bores444of the interbody device412as shown inFIG.27. When screwed into a first position, the shoulders466of the cam screws413do not reduce the clearance area of the first angled screw bore446, the second angled screw bore447, or the third angled screw bore448, thereby allowing a surgeon or other user to drive anchoring members414into the vertebral bodies above and below the interbody device412while the cam screws413are pre-threaded into the interbody device412. Once the anchoring members414are anchored into the vertebral bodies above and below the interbody device412, a surgeon may then adjust or rotate the cam screws413approximately a quarter of a turn, into a second position, as shown inFIG.31. In one embodiment, once the cam screws413are tightened approximately a quarter of a turn, the shoulders466will bottom out against the head452of the anchoring members414. In doing so, the shoulder466of the cam screw413will prevent back-out of the anchoring member414.

In one embodiment, the cam screw413may be tightened using a cam tool513shown inFIGS.42-43. In one embodiment, the cam tool513includes a shaft514and a cam screw interface515at one end of the shaft514. The cam screw interface515includes a first shoulder516aand a second shoulder516b. In this example embodiment, the first shoulder516aand the second shoulder516bare identical (e.g., mirror images). The cam screw interface515also includes a cam screw seat517. The cam screw seat517is configured to receive the head462of the cam screw413, such that the shoulders516of the cam tool513engage with the shoulders466of the cam screw413when a torque is applied to the cam tool513. In doing so, the cam tool513can be used to turn the cam screw413while the cam screw413is threaded into the interbody device412.

In other embodiments, the cam screw413may be turned using other types of tools. For example, the cam screw413can be designed to receive several different types of drivers, including a slotted screw driver, a Phillips-head screwdrivers, an Allen wrench screwdriver, a hexagonal drive, a torx drive, a Robertson drive, a tri-wing screwdriver, an Allen security driver, a torx security driver, a Pozidriv, a clutch drive, a spanner, a Schrader drive, a nut driver, a hex wrench, a node security driver, any combination of the listed driver interfaces, and any other type of driver interface.

Using cam screws413to prevent back-out of anchoring members414as described herein may provide certain benefits relative to other implants. First, due to the unique shape of the head462, the cam screws413can be partially screwed into the interbody device412prior to surgery without reducing the clearance of the first angled screw bore446, the second angled screw bore447, or the third angled screw bore448. Since the surgeon does not need to turn the cam screw413several full turns, surgery time is reduced. Additionally, since the cam screw413only needs to be turned approximately a quarter of a turn to prevent back-out of the anchoring members414, it will be easier for the surgeon to know when the cam screw413is fully screwed into place. Further, due to the unique shape of the head462, it will be obvious to the surgeon when the shoulder466is correctly positioned to prevent back-out of the anchoring member414.

As shown inFIGS.45-47, the bone barb418is characterized by a curved shaft473having a constant diameter, but other configurations may be used. The bone barb418has a head472at a first end, and a tip474at a second end, the nomenclature first and second being arbitrary. In this example embodiment, the tip474is beveled, but other configurations may be used. The head472includes a threaded socket475in its upper surface that is configured to receive an installation tool. The underside of the head472further includes a rounded shoulder476that bottoms out against the interbody device412when the bone barb418is fully inserted into the first angled screw bore446, the second angled screw bore447, or the third angled screw bore448. The head472also has a flat477on one side and another flat on the other side. A plurality of grooves (or similar feature)480,481,482,483are provided on the outside surface of the bone barb418. In one embodiment, four grooves are provided, while in other embodiments fewer or more grooves may be provided (e.g., 3, 5, etc.). In this example embodiment, the grooves480,481,482,483extend from the tip474to the head472. The grooves reduce the cross-sectional area of the barbs thereby reducing the amount of material (bone) that has to be displaced in order for the barbs to be impacted into the vertebral bone. Further, the bone barb418has a plurality of serrations478on the surface of the curved shaft473. These serrations478improve the stability of the bone barb418when inserted into the vertebral bone and assist in preventing back-out of the bone barb418.

It should be appreciated that the first angled screw bore446, the second angled screw bore447, and the third angled screw bore448of the interbody device412are configured to receive the bone barbs418in a similar manner as the bone screws416. Therefore, the bone barbs418may be used with the interbody device412according to the disclosure above.

Referring now toFIGS.48-56, an installation tool700is shown according to an example embodiment. In certain embodiments, the installation tool700may be used to insert or install an implant750and anchoring members into a patient. The implant750may be or share similar features with any other implants described herein. For example, in one embodiment, the installation tool700is used with implant400. In certain embodiments, the implant750is substantially similar to the implant shown inFIG.44, except as described herein. In other embodiments, the implant750may be comprised entirely of solid material or may be comprised entirely of porous material. In certain embodiments, the implant750may be any implant configured to be installed using the installation tool700, as will be described herein.

As shown inFIG.48, the installation tool700may be configured to receive an implant750, the installation tool700and implant750forming an installation assembly800(seeFIG.51). For example, as shown inFIG.48, the installation tool700may controllably receive an implant750, such that the implant750is controllably attached to the installation tool. Further, as shown inFIG.49, the installation tool700may include a retention member that may controllably release the implant750as will be described further herein. In certain embodiments, the retention member may include the first arm714and the second arm715.

FIG.50shows an exploded view of the installation tool700according to an example embodiment. In this example embodiment, the installation tool700includes a tool body710, which further includes an interface body712. The installation tool700further includes a first arm714and a second arm715positioned opposite the first arm714across the interface body712. In certain embodiments, the first arm714and the second arm715may be used to secure the implant750to the interface body712as will be described further herein. In certain embodiments, the first arm714is identical to the second arm715. In other embodiments, the first arm714is a mirror image of the second arm715.

According to certain embodiments, the installation tool700further includes a control shaft716disposed within the installation tool body710. The control shaft716may include a threaded shaft726near a first end, and a plate interface736positioned near a second end, opposite the first end. In certain embodiments, the threaded shaft726may engage with a threaded bore located inside the installation tool body710, such that rotating the control shaft716will cause the threaded shaft726to rotate within the threaded bore inside the installation tool body. Further, rotating the control shaft716will also cause the control shaft716to translate linearly within the installation tool body710, as will be described further herein. Further, the plate interface736is configured to receive a control plate720, which is secured to the control shaft716. In certain embodiments, the control plate is720is secured to the plate interface736using two retention rings724. In an example embodiment, the retention rings724are horseshoe retention rings, however, the control plate720may be secured to the control shaft716using any type of retention ring, such as a welding ring, c-clips, or any other type of retaining ring or other structure.

The installation tool700may further include a plurality of spring members718. For example, the spring members718may be leaf spring in an example embodiment. The plurality of spring members718may be used to retain a plurality of anchoring members within the interface body712, as will be described further herein. In certain embodiments, the spring members718may be welded to the interface body712. In other embodiments, the spring members718may be secured to the interface body712using other means, such as an adhesive, or the spring members718may be secured to the interface body712using a screw or nut and bolt. In this example embodiment, the installation tool700may also include a plurality of pins730,732. In this embodiment, the pins730may be used to secure the first arm714and the second arm715to the interface body712. Further, the two pins732may be used to secure the control plate720within the interface body712, such that the control plate720may translate linearly within the interface body712in response to the control shaft716being turned, as will be described further herein.

Referring now toFIGS.51and52, an example embodiment of the installation assembly800is depicted. In this example embodiment, the implant750is secured to the interface body712. More specifically, in certain embodiments, the interface body712may have an interface face713configured to receive the face of the implant750. For example, the interface face713may include cutout slots for the cam screws413(seeFIG.31) located on the face of an implant750. Further, the interface face713may include slots configured to let anchoring members pass from the interface body712, through the implant750, and into an adjacent bone, as will be described further herein.

Referring now toFIGS.53and54, cross-section views of the interface body712are shown according to an example embodiment. In this example embodiment, the implant750has a first tool interface702and a second tool interface704configured to receive the first arm714and the second arm715, respectively. In this example embodiment, the first arm714and the second arm715are used to secure the implant750to the installation tool700.

In certain embodiments, the arms714,715are controllably movable from a first, open position, as shown inFIG.53, to a second, closed position shown inFIG.54, and every position there in between. In certain example embodiments, the position of the arms714,715is controlled using the control shaft716. In example embodiments, the control plate720is secured to the control shaft716using pins732and retention rings724, such that the control plate720will move linearly proportionally to the control shaft716moving linearly within the tool body710. In an example embodiment, the control shaft716may be turned, such that the threaded shaft726rotates within a threaded bore inside the tool body712, and the plate interface736rotates within the control plate720. As the threaded shaft726rotates within the threaded bore, the control shaft716and control plate720will also translate linearly within the installation tool700. For example, in certain embodiments, when the control shaft716is turned in a clockwise direction, the control plate720will move in a direction towards the interface face713, and when the control shaft716is turned in a counter-clockwise direction, the control plate720will move in a direction away from the interface face713.

In certain embodiments, the control plate720is also connected to the first arm714and the second arm715using pins732. In this example embodiment, the pins are inserted (e.g. using a press fit, friction fit, slip fit, etc.) into bores in the control plate720and bores in the arms714,715. The arms714,715further include a pin slot731configured to receive a pin730, such that the pin730may translate within the pin slot731. In certain example embodiments, the interface body712further includes bores configured to receive the pins730, such that the pins730may be inserted (e.g. using a press fit or friction fit) into the interface body712and through the pin slot731of the arms714,715.

In certain embodiments, when the control shaft716is turned in a direction that causes the control plate720to translate in a direction towards the interface face713, the arms714,715will move into an open position, until the pin730bottoms out in the pin slot731, as shown inFIG.53. In this position, the implant750may be received by the installation tool700at the interface face713. Then, in certain embodiments, the control shaft716may be rotated such that the control plate720will translate in a direction away from the interface face713. In doing so, the arms714,715will move into a closed position, as shown inFIG.54, until the arms714,715bottom out within the tool interfaces702,704, thereby securing the implant750to the installation tool700.

Referring now toFIGS.55and56, another cross sectional view of the installation tool700is shown. In this example embodiment, the implant750is secured to the installation tool700. As shown inFIG.55, a bone barb418may be positioned within the interface body712. In this example embodiment, the spring member718secures the bone barb418within the interface body. However, it should be appreciated that, in other embodiments, other types of springs and biasing members may be used to retain the bone barb418within the interface body712. Once the implant750is positioned in a desired location, a drive member may be used to drive bone barbs418into adjacent bones. For example, in an example embodiment, the drive member may be an impactor740. In this embodiment, the impactor740may be used to drive bone barbs418into adjacent bones. In this example embodiment, the spring member718generally prevents the bone barb418from moving within the interface body712, however, the impactor740may apply a force to the bone barb418sufficient to release the bone barb418from the spring member718. Then, the impactor740may be used to drive the bone barb418into a bone adjacent the implant750.

In alternative embodiments, the drive member may be an actuator. For example, in certain embodiments, the drive member may be a threaded actuator. Alternatively, the drive member may be a manual actuator, a pneumatic actuator, a hydraulic actuator, an electric actuator, a spring-based actuator, or a motorized actuator. Further, the drive member may be a mechanical mechanism, such as a lever, a mallet, a screw, etc.

Referring now toFIG.57, a flow diagram representation of a method850of installing an interbody device is shown according to one embodiment. In the method850, the boxes represented with dashed lines (e.g.851,854) are optional steps, depending on whether an anchoring member, such as a bone barb418, is utilized in the installation process. In further embodiments, other steps may be omitted and/or added to the method. It should be noted that the order of the steps depicts an exemplary method, however, the steps do not need to be performed in this order, as will be made clear below.

At step851, at least one anchoring member is installed into an installation tool. For example, this step may involve loading a bone barb418into the interface body712, as shown inFIG.55. In certain embodiments, the bone barb418is secured in place by the spring member718, as shown inFIG.55, until the bone barb418is driven out of the interface body712by the impactor740, as shown inFIG.56. In certain embodiments, the anchoring member, such as a bone barb416, may be loaded into the interface body412through the interface face713. In other embodiments, the interface body712may have slots on the top and/or bottom surface of the interface body712that are configured to receive anchoring members, such as a bone barb416. In other embodiment, the implant750may secured to the interface face713, and the anchoring members may then subsequently be loaded through the implant750and into the interface body712. In further embodiments, the installation tool700may be loaded with anchoring members using any combination of the methods described above. It should be noted that step851need not necessarily be performed first, as will be discussed further herein.

At step852, an interbody device, or an implant, is received at an interface face of an interface body of an installation tool. In an example embodiment, this step may involve using the control shaft416to adjust the arms714,715into an open position, such as the position shown inFIG.53. The implant750may then be received by the interface face713. In certain embodiments, the implant750may then be secured by the arms714,715, as described above.

At step853, an interbody device, or an implant, is inserted into a desired location in a patient. For example, in certain embodiments, an incision is made on the left side of the abdomen and the abdominal muscles are retracted to the side. The abdominal contents lay inside a large sack (peritoneum) that can also be retracted, thus allowing the spine surgeon access to the front of the spine without actually entering the abdomen. The interbody device, or implant750, may then, for example, be inserted between two adjacent lumbar vertebrae. However, the implant may be placed into a desired location using any number of surgical methods.

At step854, at least one anchoring member, such as a bone barb, is driven into an adjacent bone. In certain embodiments, an impactor740may be received within the installation tool700, as shown inFIG.55. The impactor740may then be used to drive the bone barb418out of the installation tool700and into an adjacent bone. In certain embodiments, the implant750may be configured to receive a plurality of anchoring members, such as bone barbs418. For example, the implant750may be configured to receive three bone barbs418. In this example, in step851, three bone barbs418may be loaded into the installation tool700. Step851, which involves loading the anchoring members into the installation tool700, may be performed before step852, after step852, after step853, or after step853. During step854, the anchoring members may be driven into the adjacent bone individually or simultaneously. For example, if the implant750utilizes three anchoring members, such as bone barbs418, all three bone barbs418may be driven into the adjacent bones at the same time using just one impactor740, or using a plurality of impactors740.

At step855, an interbody device, or and implant, is controllably released from an installation tool. Once the implant750is inserted into a patient, and the implant750is secured to adjacent bones using anchoring members, the implant750may be released from the installation tool700so that the installation tool700may be removed from the patient. In example embodiments, releasing the implant750from the installation tool700may involve turning a control shaft716to move the arms into an open position, as described above.

Although the figures and description may illustrate a specific order of method steps, the order of such steps may differ from what is depicted and described, unless specified differently above. Also, two or more steps may be performed concurrently or with partial concurrence, unless specified differently above. Such variation may depend, for example, on the hardware systems chosen and on designer choice. All such variations are within the scope of the disclosure.

It should be appreciated that dimensions of the components, structures, and/or features of the present implants and installation instruments may be altered as desired within the scope of the present disclosure. Furthermore, the various embodiments disclosed herein may share certain features (e.g., a same or similar bone screw, screw retention mechanism, implant shape, etc.) with the implants disclosed in U.S. Publication No. 2017/0224502, which is incorporated herein by reference in its entirety.