Intervertebral implant

The present application relates generally to vertebral implants and methods of use, and more particularly to implants that include gaps around a periphery of the implant body.

The spine is divided into four regions comprising the cervical, thoracic, lumbar, and sacrococcygeal regions. The cervical region includes the top seven vertebral members identified as C1-C7. The thoracic region includes the next twelve vertebral members identified as T1-T12. The lumbar region includes five vertebral members L1-L5. The sacrococcygeal region includes nine fused vertebral members that form the sacrum and the coccyx. The vertebral members of the spine are aligned in a curved configuration that includes a cervical curve, thoracic curve, and lumbosacral curve. Intervertebral discs are positioned between the vertebral members and permit flexion, extension, lateral bending, and rotation.

Various conditions may lead to damage of the intervertebral discs and/or the vertebral members. The damage may result from a variety of causes including a specific event such as trauma, a degenerative condition, a tumor, or infection. Damage to the intervertebral discs and vertebral members can lead to pain, neurological deficit, and/or loss of motion.

Various procedures include replacing the entirety or a section of a vertebral member, the entirety or a section of an intervertebral disc, or both. One or more replacement implants may be inserted to replace the damaged vertebral members and/or discs. The implants may further include bone growth material to facilitate fusion of the implant to one or both adjacent vertebral members.

The present application is directed to implants that fit within an intervertebral space formed between first and second vertebral members. The implant may include a body with a central web and first and second outwardly-extending flanges. The first and second flanges may be spaced apart along the central web. The body may include an exterior surface formed by one or more of the central web and the flanges. The body may further include a height defined by a superior surface that contacts the first vertebral member and an inferior surface that contacts the second vertebral member. First and second spaces may be formed within an interior of the exterior surface and may extend the height of the body. A first gap may be formed in the exterior surface on a first side of the central web, and the first gap may be in communication with the first space and extend. A second gap may be formed in the exterior surface on a second side of the central web. The second gap may be in communication with the second space and extend the height of the body.

FIG. 1 is a perspective view of a implant according to one embodiment;

FIGS. 2-10 are top views of implants according to various embodiments.

FIG. 11 is a side view of an implant according to one embodiment.

FIG. 12 is a side view of an implant according to one embodiment.

FIG. 13 is a side view of an implant according to one embodiment.

FIG. 14 is a side view of an implant according to one embodiment.

FIG. 15 is a side view of a mount according to one embodiment.

FIG. 16 is a perspective view of a cover according to one embodiment.

FIG. 17 is a top view of an implant with a cover according to one embodiment.

FIG. 18 is a perspective view of an implant with a cover according to one embodiment.

The present application is directed to implants for positioning within an intervertebral space formed between first and second vertebral members. FIG. 1 illustrates one embodiment of an implant 10 with a superior surface 91 to contact against a first vertebral member, and an inferior surface 92 to contact against a second vertebral member. The implant 10 includes a central web 20 that extends between first and second flanges 30 , 40 . The flanges 30 , 40 are shaped to form gaps 50 that extend the height of the implant 10 . Spaces 51 , 52 in communication with the gaps 50 are formed in an interior of the implant 10 to hold bone growth material.

The web 20 extends between the flanges 30 , 40 and forms a central section of the implant 10 . Web 20 may include a variety of shapes and sizes. FIGS. 1 and 2 include the web 20 with a substantially constant width, with FIG. 3 including a web 20 with a variable width. The web 20 of FIG. 3 reduces to a neck 26 at an intermediate point between the flanges 30 , 40 . The width increases on each side of the neck 26 with the width being larger at the second flange 40 than at the first flange 30 .

Web 20 may also include multiple different sections. FIG. 4 illustrates an embodiment with the web 20 formed by multiple sections 21 , 22 , 23 that are spaced apart with spaces 24 formed therebetween. The multiple sections 21 , 22 , 23 and spaces 24 may include the same or different shapes and sizes. FIG. 5 illustrates another embodiment including a web 20 with a brace 25 branching off and connecting with the first flange 30 . In another embodiment, web 20 is constructed of a single section that includes an aperture that extends between the superior and inferior surfaces 91 , 92 .

Web 20 may further be positioned at various lateral locations within the central section of the implant 10 . FIGS. 1 and 2 illustrate an embodiment with the web 20 laterally centered within the implant 10 and positioned at a middle of each of the flanges 30 , 40 . In other embodiments as illustrated in FIG. 5 , the web 20 is laterally offset away from a center of the implant 10 . In some embodiments as illustrated in FIGS. 1, 2, and 5 , the web 20 is laterally spaced the same distance along the first and second flanges 30 , 40 . Alternatively as illustrated in FIG. 6 , the web 20 is spaced at laterally different positions along the first and second flanges 30 , 40 .

The first and second flanges 30 , 40 are space apart along the web 20 . The flanges 30 , 40 may be the same shape and size, or may include different shapes and sizes. FIG. 7 includes an embodiment with each of the flanges 30 , 40 being the same shape and size. FIG. 2 is an embodiment with the first flange 30 including a different shape than the second flange 40 . FIG. 8 includes an embodiment with the flanges 30 , 40 including different shapes and sizes.

As illustrated in FIG. 2 , the first flange 30 may include a first arm 31 that extends outward from a first side of the web 20 , and a second arm 32 that extends outward from a second side of the web 20 . Each arm 31 , 32 includes an end 33 that forms a side of a gap 50 . The arms 31 , 32 may include the same shape and size as illustrated in FIG. 2 , or may include different shapes and/or sizes as illustrated in FIGS. 5 and 6 . Likewise, the second flange 40 may include first and second arms 41 , 42 as illustrated in FIG. 2 . Each arm 41 , 42 includes an end 43 that forms a side of a gap 50 . Arms 41 , 42 may include the same or different shapes and/or sizes.

In one embodiment, one of the flanges 30 , 40 includes a single arm. FIG. 8 illustrates an embodiment with the first flange 30 including a single arm 31 . The first gap 50 a is formed between an end 33 of the single arm 31 and end 43 of arm 41 . The second gap 50 b is formed between the web 20 and the end 43 of arm 42 . In one embodiment as illustrated in FIG. 9 , the implant 10 includes a single flange 30 (i.e., there is no second flange 40 ). Each gap 50 is formed between arm ends 33 and the web 20 .

In one embodiment as illustrated in FIG. 10 , one or both of the flanges 30 , 40 include ends 34 , 44 with enlarged widths. The enlarged ends 34 , 44 are adjacent to the gaps 50 . The enlarged ends 34 , 44 include a larger surface area adjacent to the gaps 50 to distribute the forces applied to the implant 10 from the first and second vertebral members and alleviate specific stresses from occurring at the ends 33 , 43 of the flanges 30 , 40 .

As illustrated in FIG. 11 , the implant 10 includes a height H measured between the superior surface 91 and the inferior surface 92 . In one embodiment, the height H is substantially the same across the implant 10 . In other embodiments, the height H may vary across the implant. FIG. 12 illustrates an embodiment with a portion of the first flange 30 including a smaller height H′. This smaller height facilitates insertion of the implant 10 between the vertebral members with the section with the smaller height H′ being initially inserted into the intervertebral space. Various other sections of the implant 10 may include larger or smaller heights depending upon the context of use.

The gaps 50 extend the height H of the implant 10 between the superior and inferior surfaces 91 , 92 . In one embodiment, the gaps 50 are formed between the arm ends 33 , 43 on opposing sides of the web 20 . In one embodiment, the gaps 50 are formed between the arm ends 33 , 43 . In other embodiments, the gaps 50 are formed by an arm end 33 or 43 , and the web 20 . FIG. 9 includes an embodiment with each of the gaps 50 a, 50 b formed between ends 33 of the arms 31 , 32 and the web 20 .

The gaps 50 may include the same or different widths W. FIG. 2 includes each of the gaps 50 with the same width W. FIG. 8 includes a first gap 50 a including a width W 1 that is larger than the width W 2 of the second gap 50 b.

The widths W of the gaps 50 may be constant or may vary along the height. FIG. 11 includes an embodiment with the width W being constant along the height H between the superior and inferior surfaces 91 , 92 . FIG. 13 includes an embodiment with a variable width with the end 33 of the first flange 30 being straight and the end 43 of the second flange 40 including a curved shape. The ends 33 , 43 cause the width W to be larger in the middle of the gap 50 than at the outer ends at the superior and inferior surfaces 91 , 92 . FIG. 14 includes an embodiment with the gap 50 formed between the first flange 30 and the web 20 . The width W is smallest at the superior surface 91 and largest at the inferior surface 92 .

Interior spaces 51 , 52 are in communication with the gaps 50 and function to contain bone growth material. The spaces are bounded on the lateral sides and are unbounded on the superior and inferior sides. The spaces 51 , 52 may include the same or different shapes and sizes. FIG. 2 includes one embodiment with each of the spaces 51 , 52 including the same shape and size. Space 51 is positioned inward from the gap 50 a and is bounded by the inner edges of arm 31 , arm 41 , and web 20 . Space 52 is positioned inward from gap 50 b and is bounded by the inner edges of arm 32 , arm 42 , and web 20 . FIG. 5 includes an embodiment with space 51 being smaller than space 52 .

A plate 80 may be formed on a lateral side of the implant 10 . The plate 80 may be a separate piece that is attached to the implant, or it may be integrally formed with the body (i.e., the body plate 80 includes a unitary construction). Mount 80 extends above one or both of the superior and inferior surfaces 91 , 92 to contact against the lateral sides of the vertebral members to maintain the implant 10 positioned within the intervertebral space. Mount 80 also prevents the implant 10 from being over-inserted into the intervertebral space. One or more apertures 81 may extend through the mount 80 . Apertures 81 are sized to receive fasteners (not illustrated) to attach the implant 10 to the vertebral members. In one embodiment as illustrated in FIG. 15 , apertures 81 a are positioned at a central height of the mount 80 and angle upward towards the superior surface 91 for engaging the fasteners with the first vertebral member. Apertures 81 b are angled downward towards the inferior surface 92 to engage the second vertebral member. In one embodiment, as illustrated in FIG. 15 , the plate 80 extends across the entire body. In another embodiment as illustrated in FIG. 12 , the plate 80 extends across a portion of the body.

The apertures 81 may extend through the plate 80 and into one of the flanges 30 , 40 and/or the web 20 . FIG. 7 illustrates one embodiment with the aperture 81 extending through the flange 40 and into the web 20 . FIG. 2 illustrates an embodiment with the apertures 81 extending through the flange 40 and into the spaces 51 , 52 respectively.

Teeth 75 may be positioned on one or both of the superior and inferior surfaces 91 , 92 . Teeth 75 may include an angled orientation to facilitate insertion of the implant 10 into the intervertebral space, and maintain the proper positioning within the space. Teeth 75 may extend across an entirety or limited sections of the inferior and superior surfaces 91 , 92 . Embodiments of teeth for an intervertebral implant are disclosed in U.S. patent application Ser. Nos. 11/394,452 and 11/412,330 that are each herein incorporated by reference.

A cover 60 may be attached to the implant 10 to extend across one or more of the gaps 50 . FIG. 16 illustrates one embodiment of the cover 60 that includes a first section 63 with opposing, spaced-apart arms 61 , 62 . The cover 60 functions to extend across one or more of the gaps 50 and prevent inadvertent lateral removal of the bone growth material within the spaces 51 , 52 .

In one embodiment, arms 61 , 62 are connected to the first section 63 to be moveable in the directions of arrow Z. This may be caused by the cover 60 being constructed of an elastic material. The cover 60 is sized to deform when inserted onto the spacer 10 with the arms 61 , 62 expanding outward. Once attached, the arms 61 , 62 apply a compressive force to the exterior lateral sides of the implant 10 to maintain attachment of the cover 60 . Apertures 64 may further be spaced about the cover 60 and sized to receive fasteners to further attach the cover 60 to the implant 10 .

In another embodiment, arms 61 , 62 are movably connected to the first section 63 such as by hinges, pivots, or other like structure. The arms 61 , 62 may move apart during attachment of the cover to allow the arms 61 , 62 to extend along each side of the implant 10 . Once positioned, the arms 61 , 62 may move inward to contact against the exterior lateral sides of the implant 10 . Apertures 64 may further be positioned around the cover 60 to receive fasteners to attach the cover 60 to the implant 10 .

In use, the implant 10 is initially inserted into the intervertebral space. Prior to insertion or after insertion, bone growth material is inserted into the spaces 51 , 52 . The cover 60 is then attached to the exterior lateral sides of the implant 10 . The cover 60 may extend across one or more of the gaps 50 to maintain the bone growth material.

FIG. 17 includes one embodiment with the cover 60 attached to the implant 10 . The first section 63 includes a shape to substantially match the second flange 40 . Arms 61 , 62 substantially match the shape of the second flange 40 , and include a length to extend across the gaps 50 and contact against the first flange 30 . Cover 60 may also be positioned against the mount 80 and extend over the apertures 81 to prevent back-out of the fasteners. FIG. 18 includes an embodiment with a single arm 61 extending outward from the first section 63 . The arm 61 extends across the first gap 50 a. In this embodiment, arm 61 includes a smaller height than the gap 50 a.

Cover 60 may also be attached to the implant 10 in other manners In one embodiment, implant 10 includes notches along the exterior lateral side and the cover 60 includes outwardly-extending fingers. During attachment, the fingers slide across the exterior lateral side and mount within one of the notches to maintain the attachment. Other attachments may include snap fits and press fits.

The implant 10 may be inserted into the intervertebral space from a variety of directions. In one embodiment, the implant 10 is inserted in an anterior approach with the mount 80 contacting against the anterior lateral sides of the vertebral members. Other applications contemplate other approaches, including posterior, postero-lateral, antero-lateral and lateral approaches to the spine, and accessing other regions of the spine, including the cervical, thoracic, lumbar and/or sacral portions of the spine.

Spatially relative terms such as “under”, “below”, “lower”, “over”, “upper”, and the like, are used for ease of description to explain the positioning of one element relative to a second element. These terms are intended to encompass different orientations of the device in addition to different orientations than those depicted in the figures. Further, terms such as “first”, “second”, and the like, are also used to describe various elements, regions, sections, etc and are also not intended to be limiting. Like terms refer to like elements throughout the description.

As used herein, the terms “having”, “containing”, “including”, “comprising” and the like are open ended terms that indicate the presence of stated elements or features, but do not preclude additional elements or features. The articles “a”, “an” and “the” are intended to include the plural as well as the singular, unless the context clearly indicates otherwise.

The present invention may be carried out in other specific ways than those herein set forth without departing from the scope and essential characteristics of the invention. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.