Patent Description:
In a healthy intervertebral disc, cells within the nucleus pulposus produce an extracellular matrix (ECM) containing a high percentage of proteoglycans. These proteoglycans contain sulfated functional groups that retain water, thereby providing the nucleus pulposus with its cushioning qualities. These nucleus pulposus cells may also secrete small amounts of cytokines as well as matrix metalloproteinases (MMPs). These cytokines and MMPs help regulate the metabolism of the nucleus pulposus cells.

In some instances of degenerative disc disease (DDD), gradual degeneration of the intervertebral disc is caused by mechanical instabilities in other portions of the spine. In these instances, increased loads and pressures on the nucleus pulposus cause the cells within the disc (or invading macrophages) to emit larger than normal amounts of the above-mentioned cytokines. In other instances of DDD, genetic factors or apoptosis can also cause the cells within the nucleus pulposus to emit toxic amounts of these cytokines and MMPs. In some instances, the pumping action of the disc may malfunction (due to, for example, a decrease in the proteoglycan concentration within the nucleus pulposus), thereby retarding the flow of nutrients into the disc as well as the flow of waste products out of the disc. This reduced capacity to eliminate waste may result in the accumulation of high levels of proinflammatory cytokines and/or MMPs that may cause nerve irritation and pain.

As DDD progresses, toxic levels of the cytokines and MMPs present in the nucleus pulposus begin to degrade the extracellular matrix. In particular, the MMPs (as mediated by the cytokines) begin cleaving the water-retaining portions of the proteoglycans, thereby reducing their water-retaining capabilities. This degradation leads to a less flexible <NUM> nucleus pulposus, and so changes the loading pattern within the disc, thereby possibly causing delamination of the annulus fibrosus. These changes cause more mechanical instability, thereby causing the cells to emit even more cytokines, typically thereby upregulating MMPs. As this destructive cascade continues and DDD further progresses, the disc begins to bulge ("a herniated disc"), and then ultimately ruptures, causing the nucleus pulposus to contact the spinal cord and produce pain.

One proposed method of managing these problems is to remove the problematic disc and replace it with an intervertebral implant that restores disc height and allows for bone growth therethrough for the fusion of the adjacent vertebrae. These devices are commonly called "fusion devices".

US Patent Publication No. <CIT> discloses a plurality of implantable trial distraction elements, each spacer element having a different axial thickness from each other element. The axial thicknesses are selected to increase by an increment from one element to another. The trial spacer elements include beveled flanges and non-parallel annular groove walls. A set of tapered intervertebral spacers is also disclosed. Each spacer has a predetermined maximum depth and a predetermined minimum depth, each spacer having a different maximum flange thickness dimension and a different minimum flange thickness dimension. An angle of an overall taper of each spacer in the set can be different to the angle of the overall taper of at least one other spacer in the set. US Patent Publication <CIT> discloses an implant that provides a user with a range of angular orientations of the end plates.

There is provided a kit of intervertebral implants.

Optional further features of the kit are defined in the dependent claims.

In accordance with the present disclosure, a kit of intervertebral implants are each configured to be inserted into an intervertebral space. Each intervertebral implant of the kit includes a leading end and a trailing end, arranged such that the leading end is spaced from the trailing end in an insertion direction into the intervertebral space. Each intervertebral implant of the kit further includes an anterior side wall and a posterior side wall each extending between the leading end and the trailing end, wherein the anterior and posterior side walls are opposite each other along a lateral direction that is perpendicular to the insertion direction. Each intervertebral implant of the kit further includes upper and lower endplates each made of Titanium or an alloy thereof and spaced from each other along a transverse direction that is perpendicular to each of the insertion direction and the lateral direction. Each of the endplates defines a respective outer surface that is configured to abut respective superior and inferior vertebral bodies when the implant is disposed in the intervertebral space. The anterior side wall of a first intervertebral implant of the kit has a height greater than that of the posterior side wall along the transverse direction, such that the upper and lower endplates of the first intervertebral implant define a first angle with respect to each other as they extend along the lateral direction, and each of the upper and lower endplates of the first intervertebral implant define respective thicknesses at the anterior side wall. The anterior side wall of a second intervertebral implant of the kit has a height greater than that of the posterior side wall along the transverse direction, such that the upper and lower endplates of the second intervertebral implant define a second angle with respect to each other as they extend along the lateral direction that is greater than the first angle. Each of the upper and lower endplates of the second intervertebral implant defines respective thicknesses at the anterior side wall that are equal to the respective thicknesses of the upper and lower endplates of the first intervertebral implant at the anterior side wall, as claimed in claim <NUM>.

The foregoing summary, as well as the following detailed description of embodiments of the application, will be better understood when read in conjunction with the appended drawings. For the purposes of illustrating the implants and systems of the present application, there is shown in the drawings preferred embodiments. It should be understood, however, that the application is not limited to the precise implants, and systems shown. In the drawings:.

Referring to <FIG>, an intervertebral implant <NUM> is implanted in an intervertebral disc space <NUM> that is defined by a first vertebral body <NUM> and a second vertebral body <NUM>. The first vertebral body <NUM> can be referred to as a superior vertebral body, and the second vertebral body <NUM> can be referred to as an inferior vertebral body. The disc space <NUM> has been prepared such that at least a portion up to all of the natural intervertebral disc has been removed, thereby creating a void that is configured to receive the intervertebral implant <NUM>. The first vertebral body <NUM> can define a superior vertebral endplate surface 22a of the intervertebral space <NUM>. The second vertebral body <NUM> can define an inferior vertebral endplate surface 22b of the intervertebral space <NUM>.

Referring now also to <FIG>, and as described in more detail below, the present disclosure recognizes that it may be desirable to construct a Titanium intervertebral implant. A Titanium intervertebral implant can be made from Titanium or one or more alloys thereof. The Titanium can be a commercially pure Titanium. For instance, the present disclosure recognizes that Titanium implants allow for bone to grow into the implant as opposed to intervertebral implants made from poly-ether-ether-ketone (PEEK). However, as will become appreciated from the description below, because Titanium is a harder material than PEEK, the intervertebral implants <NUM> described herein have structural features that are different than conventional PEEK implants, including the PEEK intervertebral implant of the Oracle® Cage system that is commercially available from DePuy Synthes, Inc. , a company of Johnson and Johnson having a place of business in New Brunswick, NJ. Thus, while the implant <NUM> has certain features that render the implant <NUM> especially suitable for Titanium construction, it should be appreciated that the implant <NUM> can be made from any suitable alternative biocompatible material as desired. In one example, the implant <NUM> can be made from the material of the intervertebral implant of the SynCage™ system that is commercially available from DePuy Synthes, a company of Johnson and Johnson having a place of business in New Brunswick, NJ. Further, the implant <NUM> can be made from the material of the intervertebral implant of the Oracle® Cage system.

The intervertebral implant <NUM> defines a leading end <NUM>, and a trailing end <NUM> opposite the leading end <NUM> along a central axis of the implant <NUM>. The implant <NUM> can be elongate along the central axis. The intervertebral implant <NUM> can be inserted into the intervertebral disc space <NUM> in an insertion direction that is defined from the trailing end <NUM> to the leading end <NUM>. Thus, the leading end <NUM> can be said to be spaced from the trailing end <NUM> in a direction of insertion into the intervertebral disc space <NUM>. The leading end <NUM> can define a tapered bullet-shaped nose <NUM>. The insertion direction can be oriented along a longitudinal direction L that includes both the insertion direction and a rearward direction that is opposite the insertion direction. In one example, the nose <NUM> can be inwardly tapered both along one or both of a transverse direction T and a lateral direction L as it extends in the insertion direction. For instance, the nose <NUM> can be rounded. In one example, the nose <NUM> can be configured as in the Oracle® Cage system that is commercially available from DePuy Synthes, Inc. , a company of Johnson and Johnson having a place of business in New Brunswick, NJ. It should be appreciated, of course, that the leading end <NUM> can define any suitable alternative shape as desired. The transverse direction T is oriented substantially perpendicular with respect to the longitudinal direction L. The lateral direction A is oriented substantially perpendicular with respect to each of the transverse direction T and the longitudinal direction L.

In one example, the intervertebral implant <NUM> can be inserted into the intervertebral disc space <NUM> along a lateral approach into the intervertebral disc space. Thus, the insertion direction into the intervertebral disc space <NUM> can be defined by the anatomical lateral direction. The lateral approach can be a transpsoas approach into the lumbar region of the spine. Thus, the first and second vertebral bodies <NUM> and <NUM> can be defined by lumbar vertebrae. It should be appreciated, however, that the intervertebral implant <NUM> is not to be limited to a lumber implant, unless otherwise indicated. For instance, certain principles of the present disclosure can be applicable to an implant configured for insertion into a thoracic intervertebral disc space. Alternatively or additionally, certain principles of the present disclosure can be applicable to an implant configured for insertion into a cervical intervertebral disc space. It should be further appreciated that the implant <NUM> can be inserted into the intervertebral disc space along any approach as desired.

The leading end <NUM> and the trailing end <NUM> can be spaced from each other along the longitudinal direction L. Thus, the intervertebral implant <NUM> can be elongate along the longitudinal direction L. The intervertebral implant <NUM> further defines a first side wall <NUM> and a second side wall <NUM> that each extends from the leading end <NUM> to the trailing end <NUM>. The intervertebral implant <NUM> can define a footprint that is defined by the leading end <NUM>, the trailing end <NUM>, the first side wall <NUM>, and the second side wall <NUM>. The footprint can be sized and shaped so as to fit in the intervertebral disc space <NUM>.

The implant <NUM> can be configured to be implanted into the intervertebral space <NUM> such that the first side wall <NUM> is disposed anterior of the second side wall <NUM>, and the second side wall <NUM> is thus disposed posterior of the first side wall <NUM>. Thus, the first side wall <NUM> can be referred to as an anterior side wall. The second side wall <NUM> can be referred to as a posterior side wall. With respect to a view of the trailing end <NUM> of the implant <NUM> in the insertion direction, the first side wall <NUM> is on the left side of the implant <NUM>, and the second side wall <NUM> is on the right side of the implant <NUM>. The first and second side walls <NUM> and <NUM> can be opposite each other along the lateral direction A. The first and second side walls <NUM> and <NUM> can define respective inner side surfaces that generally face each other along the lateral direction A, and respective outer side surfaces opposite the respective inner side surfaces. Thus, the outer side surfaces face away from each other along the lateral direction A.

The intervertebral implant <NUM> further includes an upper endplate <NUM> and a lower endplate <NUM> opposite the upper endplate <NUM> along the transverse direction T. The upper endplate <NUM> defines an upper outer surface <NUM> that is configured to face the superior vertebral endplate surface 22a when the implant <NUM> is disposed in the intervertebral space <NUM>. For instance, the upper outer surface <NUM> can be configured to abut the superior vertebral endplate surface 22a. In one example, the upper outer surface <NUM> can be configured to grip the superior vertebral endplate surface 22a. For instance, the upper outer surface <NUM> can define upwardly extending teeth <NUM> that are configured to grip the superior vertebral surface 22a. The upper endplate <NUM> can further define an upper inner surface <NUM> that is opposite the upper outer surface <NUM> along the transverse direction T.

Similarly, the lower endplate <NUM> defines a lower outer surface <NUM> that is configured to face the inferior vertebral endplate surface 22b when the implant <NUM> is disposed in the intervertebral space <NUM>. For instance, the lower outer surface <NUM> can be configured to abut the inferior vertebral endplate surface 22b. In one example, the lower outer surface <NUM> can be configured to grip the inferior vertebral endplate surface 22b. For instance, the lower outer surface <NUM> can define downwardly extending teeth <NUM> that are configured to grip the inferior vertebral surface 22b. The lower endplate <NUM> can further define a lower inner surface <NUM> that is opposite the lower outer surface <NUM> along the transverse direction T Thus, the lower inner surface <NUM> can generally face the upper inner surface <NUM> along the transverse direction T. In this regard, the lower inner surface <NUM> and the upper inner surface <NUM> can face the transverse direction T or a direction oblique to the transverse direction T. The teeth <NUM> and <NUM> can be configured to engage the first and second vertebral bodies <NUM> and <NUM>, respectively, so as to prevent or minimize migration of the implant <NUM> in the intervertebral space <NUM> after implantation. The teeth <NUM> and <NUM> can be configured as in the intervertebral implant of the SynCage™ system.

The upper and lower endplates <NUM> and <NUM> can be spaced from each other along the transverse direction T so as to define a hollow interior therebetween. The intervertebral implant <NUM> can define at least one side aperture <NUM> that extends through one or both of the first and second side walls <NUM> and <NUM> at least toward the other of the first and second side walls <NUM> and <NUM> along the lateral direction A. Thus, the at least one side aperture <NUM> can be referred to as a lateral bone graft aperture. The side aperture <NUM> extending through the first side wall <NUM> can be referred to as an anterior side aperture. The side aperture <NUM> extending through the second side wall <NUM> can be referred to as an anterior side aperture.

The at least one side aperture <NUM> can extend from the respective outer side surface to the respective inner side surface. Accordingly, the at least one side aperture <NUM> can be open go the hollow interior. The at least one side aperture <NUM> can be a bone graft aperture that is configured to receive bone graft material to assist in fusion of the intervertebral implant <NUM> with either or both of the first and second vertebral bodies <NUM> and <NUM>. The bone graft material can fuse to the superior and inferior vertebral surfaces 22a and 22b of the intervertebral disc space <NUM>. In this regard, the implant <NUM> can be referred to as a fusion cage that is configured to fuse to the first and second vertebral bodies <NUM> and <NUM>. Further, the titanium endplates <NUM> and <NUM> can allow bone to grow therein to fuse the intervertebral implant <NUM> to the first and second vertebral bodies <NUM> and <NUM>.

The at least one side aperture <NUM> can extend between the first and second endplates <NUM> and <NUM>. In one example, the at least one side aperture <NUM> can extend through the implant <NUM> from the first side wall <NUM> to the second side wall <NUM> along the lateral direction A. Thus, the at least one side aperture <NUM> can be referred to as a through hole. In particular, the at least one side aperture can be referred to as a lateral through hole. Alternatively, the at least one side aperture <NUM> can extend from the first side wall <NUM> along the lateral direction A, and can terminate without passing through the second side wall <NUM>. Otherwise stated, the at least one side aperture <NUM> can define a first opening for the insertion of bone graft material at one side of the implant <NUM>, but does not define a second opening opposite the first opening with respect to the lateral direction A. Thus, in one example the at least one side aperture <NUM> can extend through the first side wall <NUM>, but not through the second side wall <NUM>. As bone graft material is inserted through the at least one side aperture <NUM>, the bone graft material is forced through vertical bone graft holes that extend through one or both of the upper and lower endplates <NUM> and <NUM>, respectively, as described in more detail below.

The at least one side aperture <NUM> can include first and second side apertures 46a and 46b spaced from each other along the longitudinal direction L. The first side wall <NUM> can define a first rib <NUM> that separates the first and second side apertures 46a and 46b from each other along the longitudinal direction L. The rib <NUM> can extend from the upper endplate <NUM> to the lower endplate <NUM>. The rib <NUM> can be oriented along the transverse direction T. Similarly, when the second side wall <NUM> defines respective first and second side apertures 46a and 46b, the second side wall <NUM> can define a second rib <NUM> that separates the first and second apertures 46a and 46b from each other. The second rib <NUM> can extend from the upper endplate <NUM> to the lower endplate <NUM>. The second rib <NUM> can be oriented along the transverse direction T. The ribs <NUM> and <NUM> can define a thickness along a direction that is perpendicular to the transverse direction T. The thickness can increase as the lordotic angle of the intervertebral implent <NUM> increases, as described in more detail below. Thus, a first intervertebral implant <NUM> of a kit can have a first lordotic angle, and the second intervertebral implant <NUM> of the kit can have a second lordotic angle greater than the first lordotic angle. The thickness of one or both of the ribs <NUM> and <NUM> of the second intervertebral implant <NUM> of the kit can be greater than the respective thickness of one or both of the ribs <NUM> and <NUM> of the first intervertebral implant <NUM> of the kit. The thickness can be measured along the longitudinal direction L. Alternatively or additionally, the first intervertebral implant <NUM> of a kit can define a first length along the longitudinal direction L, and the second intervertebral implant <NUM> of the kit define have a second length along the longitudinal direction L that is greater than the first length. For instance, the first and second lengths can be between and including approximately <NUM> and approximately <NUM>.

Alternatively or additionally still, the first intervertebral implant <NUM> of a kit can define a first width along the lateral direction A, and the second intervertebral implant <NUM> of the kit can define a second width along the lateral direction A that is greater than the first width. In one example, the first and second widths can be between and including approximately <NUM> and approximately <NUM>. The thickness of one or both of the ribs <NUM> and <NUM> of the second intervertebral implant <NUM> of the kit can be greater than the respective thickness of one or both of the ribs <NUM> and <NUM> of the first intervertebral implant <NUM> of the kit. The thickness can be measured along the longitudinal direction A.

The first side aperture 46a can be spaced from the second side aperture 46b in the insertion direction. Thus, the first side aperture 46a can be disposed between the second side aperture 46b and the leading end <NUM> with respect to the longitudinal direction L. Similarly, the second side aperture 46b can be disposed between the first side aperture 46a and the trailing end <NUM> with respect to the longitudinal direction L. While first and second side apertures 46a and 46b are shown in accordance with one example, it should be appreciated that the at least one side aperture <NUM> can include any number of apertures as desired.

The intervertebral implant <NUM> can further include at least one aperture <NUM> that extends through one or both of the upper and lower endplate <NUM> and <NUM> along the transverse direction T. For instance, the at least one aperture <NUM> can extend through the upper endplate <NUM> from the upper outer surface <NUM> to the upper inner surface <NUM>. Alternatively or additionally, the at least one aperture <NUM> can extend through the lower endplate <NUM> from the lower outer surface <NUM> lower inner surface <NUM>. Thus, the at least one aperture <NUM> can be referred to as a transverse or vertical aperture. The at least one vertical aperture <NUM> can be a bone graft aperture that is configured to receive bone graft material to assist in fusion of the intervertebral implant <NUM> with either or both of the first and second vertebral bodies <NUM> and <NUM>. In particular, the bone graft material can fuse to the superior and inferior vertebral surfaces 22a and 22b of the intervertebral disc space <NUM>. The at least one aperture <NUM> can extend through the upper and lower endplates <NUM> and <NUM>. Thus, the at least one aperture <NUM> can be open to each of the first and second vertebral bodies <NUM> and <NUM>. Further, the at least one aperture <NUM> can be open to the hollow interior. During operation, bone graft material can be packed inside the implant through one or both of the at least one side apertures <NUM> and the at least one vertical aperture <NUM>. The bone graft material can fuse with the first and second vertebral bodies <NUM> and <NUM> through the upper and lower endplates <NUM> and <NUM>.

In one example, the at least one aperture <NUM> that extends through the upper endplate <NUM> can be referred to as at least one upper bone graft aperture 48a. The at least one upper bone graft aperture 48a can include a plurality of upper bone graft apertures 48a. The upper bone graft apertures 48a can have different sizes as desired. For example, the upper bone graft aperture 48a can include at least one first upper bone graft aperture 50a and at least one second upper bone graft aperture 51a. The at least one first upper bone graft aperture 50a can be configured as a large aperture, and the at least one second upper bone graft aperture 51a can be configured as a small aperture. The at least one first upper bone graft aperture 50a defines a maximum first cross-sectional dimension along a plane that is defined by the longitudinal direction L and the lateral direction A. The at least one second upper bone graft aperture 51a define a second maximum cross-sectional dimension along the plane that is defined by the longitudinal direction L and the lateral direction A. The second cross-sectional dimension is smaller than the first cross-sectional dimension. The apertures 50a and 51a can be cylindrical, such that the cross-sectional dimensions of the apertures 50a and 51a can define diameters. It should be appreciated, however, that the apertures 50a and 51a can be sized and shaped as desired.

The at least one second upper bone graft aperture 51a can include a plurality of second upper bone graft apertures 51a that surround respective ones of the at least one first upper bone graft aperture 50a. The at least one first upper bone graft aperture 50a can include a plurality of first upper bone graft apertures 50a. The first upper bone graft apertures 50a can be at least partially aligned with each other along the longitudinal direction L. In one example, the respective geometric centers of the first upper bone graft apertures 50a can be aligned with each other along the longitudinal direction L. The first upper bone graft apertures 50a can also be equidistantly spaced from each other along the longitudinal direction L. Alternatively, the first upper bone graft apertures 50a can be spaced from each other at variable distances along the longitudinal direction L. Further, the large apertures <NUM> can be equidistantly spaced from the first and second side walls <NUM> and <NUM> with respect to the lateral direction A. While the implant <NUM> is illustrated as including three first upper bone graft apertures 50a, any number of first upper bone graft apertures 50a can be provided as desired. The first upper bone graft apertures 50a can all have the same maximum cross-sectional dimension or different maximum cross-sectional dimensions.

The second upper bone graft apertures 51a can be arranged about a perimeter of respective ones of the first upper bone graft apertures 50a. Thus, the first upper bone graft apertures 50a can be referred to as central upper bone graft apertures. The second upper bone graft apertures 51a can be referred to as peripheral upper bone graft apertures. The second upper bone graft apertures 51a can be arranged in several groups. The second upper bone graft apertures 51a of each group can surround the perimeter of a respective one of the first upper bone graft apertures 50a. For instance, a first group of second upper bone graft apertures 51a can be arranged about a first one of the first upper bone graft apertures 50a. The second upper bone graft apertures 51a of the first group can be equidistantly circumferentially spaced from each other. Further, the second upper bone graft apertures 51a of the first group can be spaced equidistantly from the first one of the first upper bone graft apertures 50a. Similarly, a second group of second upper bone graft apertures 51a can be arranged about a second one of the first upper bone graft apertures 50a. The second upper bone graft apertures 51a of the second group can be equidistantly circumferentially spaced from each other. Further, the second upper bone graft apertures 51a of the second group can be spaced equidistantly from the second one of the first upper bone graft apertures 50a. Similarly still, a third group of second upper bone graft apertures 51a can be arranged about a third one of the first upper bone graft apertures 50a. The second upper bone graft apertures 51a of the third group can be equidistantly circumferentially spaced from each other. Further, the second upper bone graft apertures 51a of the third group can be spaced equidistantly from the third one of the first upper bone graft apertures 50a. The second one of the first upper bone graft apertures 50a can be disposed between the first and third ones of the first upper bone graft apertures 50a along the longitudinal direction L.

It should be appreciated that one or more of the second upper bone graft apertures 51a can belong to more than one group. For instance, at least one of the second upper bone graft apertures 51a can belong to each of the first and second groups. In one example, first and second ones of the second upper bone graft apertures 51a can belong to each of the first and second groups. Further, at least one of the second upper bone graft apertures 51a can belong to the second and third groups. In one example, first and second ones of the second upper bone graft apertures 51a can belong to each of the second and third groups.

Similarly, the at least one aperture <NUM> that extends through the lower endplate <NUM> can be referred to as at least one lower bone graft aperture 48b. The at least one lower bone graft aperture 48b can include a plurality of lower bone graft apertures 48b. The lower bone graft apertures 48b can have different sizes as desired. For example, the lower bone graft aperture 48b can include at least one first lower bone graft aperture 50b and at least one second lower bone graft aperture 51b. The at least one first lower bone graft aperture 50b can be configured as a large aperture, and the at least one second lower bone graft aperture 51b can be configured as a small aperture. The at least one first lower bone graft aperture 50b defines a maximum first cross-sectional dimension along a plane that is defined by the longitudinal direction L and the lateral direction A. The at least one second lower bone graft aperture 51b define a second maximum cross-sectional dimension along the plane that is defined by the longitudinal direction L and the lateral direction A. The second cross-sectional dimension is smaller than the first cross-sectional dimension. The apertures 50b and 51b can be cylindrical, such that the cross-sectional dimensions of the apertures 50b and 51b can define diameters. It should be appreciated, however, that the apertures 50b and 51b can be sized and shaped as desired.

The at least one second lower bone graft aperture 51b can include a plurality of second lower bone graft apertures 51b that surround respective ones of the at least one first lower bone graft aperture 50b. The at least one first lower bone graft aperture 50b can include a plurality of first lower bone graft apertures 50b. The first lower bone graft apertures 50b can be at least partially aligned with each other along the longitudinal direction L. In one example, the respective geometric centers of the first lower bone graft apertures 50b can be aligned with each other along the longitudinal direction L. The first lower bone graft apertures 50b can also be equidistantly spaced from each other along the longitudinal direction L. Alternatively, the first lower bone graft apertures 50b can be spaced from each other at variable distances along the longitudinal direction L. Further, the large apertures <NUM> can be equidistantly spaced from the first and second side walls <NUM> and <NUM> with respect to the lateral direction A. While the implant <NUM> is illustrated as including three first lower bone graft apertures 50b, any number of first lower bone graft apertures 50b can be provided as desired. The first lower bone graft apertures 50b can all have the same maximum cross-sectional dimension or different maximum cross-sectional dimensions.

The second lower bone graft apertures 51b can be arranged about a perimeter of respective ones of the first lower bone graft apertures 50b. Thus, the first lower bone graft apertures 50b can be referred to as central lower bone graft apertures. The second lower bone graft apertures 51b can be referred to as peripheral lower bone graft apertures. Thus, the second lower bone graft apertures 51b can be arranged in several groups. The second lower bone graft apertures 51b of each group can surround the perimeter of a respective one of the first lower bone graft apertures 50b. For instance, a first group of second lower bone graft apertures 51b can be arranged about a first one of the first lower bone graft apertures 50b. The second lower bone graft apertures 51b of the first group can be equidistantly circumferentially spaced from each other. Further, the second lower bone graft apertures 51b of the first group can be spaced equidistantly from the first one of the first lower bone graft apertures 50b. Similarly, a second group of second lower bone graft apertures 51b can be arranged about a second one of the first lower bone graft apertures 50b. The second lower bone graft apertures 51b of the second group can be equidistantly circumferentially spaced from each other. Further, the second lower bone graft apertures 51b of the second group can be spaced equidistantly from the second one of the first lower bone graft apertures 50b. Similarly still, a third group of second lower bone graft apertures 51b can be arranged about a third one of the first lower bone graft apertures 50b. The second lower bone graft apertures 51b of the third group can be equidistantly circumferentially spaced from each other. Further, the second lower bone graft apertures 51b of the third group can be spaced equidistantly from the third one of the first lower bone graft apertures 50b. The second one of the first lower bone graft apertures 50b can be disposed between the first and third ones of the first lower bone graft apertures 50b along the longitudinal direction L.

It should be appreciated that one or more of the second lower bone graft apertures 51b can belong to more than one group. For instance, at least one of the second lower bone graft apertures 51b can belong to each of the first and second groups. In one example, first and second ones of the second lower bone graft apertures 51b can belong to each of the first and second groups. Further, at least one of the second lower bone graft apertures 51b can belong to the second and third groups. In one example, first and second ones of the second lower bone graft apertures 51b can belong to each of the second and third groups.

Each of the at least one upper bone graft aperture 48a can be aligned with a respective one of each the lower bone graft apertures 48b along the transverse direction T. Thus, the first and second upper bone graft apertures 50a and 51a can combine to define the same pattern as the pattern defined by the first and second lower bone graft apertures 50b and 51b. It should be appreciated, of course, that the first and second upper bone graft apertures 50a and 51a can combine to define any suitable first pattern as desired. Similarly, the first and second lower bone graft apertures 50b and 51b can define any suitable second pattern as desired that can be the same as the first pattern or different than the first pattern as desired. In one example, the bone graft apertures 48a and 48b can be arranged as in the intervertebral implant of the SynCage™ system.

With continuing reference to <FIG>, and as described above, the upper and lower endplates <NUM> and <NUM> are made from Titanium or at least one Titanium alloy. The present disclosure recognizes that because Titanium is a harder material than PEEK, it is desirable for the upper outer surfaces <NUM> and the lower outer surface <NUM> to have a sufficient surface area to avoid subsidence of the intervertebral implant <NUM> when implanted in the intervertebral space.

The upper outer surface has an upper overall surface area in an outermost upper perimeter of the intervertebral implant. The outermost upper perimeter can be defined, in combination, by the leading end <NUM>, the outer side surfaces of the first and second side walls <NUM> and <NUM>, and the trailing end <NUM>. The upper bone graft apertures 48a, including the first and second upper bone graft apertures 50a and 51a, combine to define an upper overall aperture area at the upper outer surface <NUM>. The upper overall surface area and the upper overall aperture area combine to define an upper overall area. In one example, the upper overall aperture area can be between approximately <NUM>% and <NUM>% of the upper overall area. For instance, in one example, the upper overall aperture area can be approximately <NUM>% of the upper overall area.

Similarly, the lower outer surface has a lower overall surface area in an outermost lower perimeter of the intervertebral implant <NUM>. The outermost lower perimeter can be defined, in combination, by the leading end <NUM>, the outer side surfaces of the first and second side walls <NUM> and <NUM>, and the trailing end <NUM>. The lower bone graft apertures 48b, including the first and second lower bone graft apertures 50b and 51b, combine to define an upper overall aperture area at the lower outer surface <NUM>. The lower overall surface area and the lower overall aperture area combine to define a lower overall area. In one example, the lower overall aperture area can be between approximately <NUM>% and <NUM>% of the lower overall area. For instance, in one example, the lower overall aperture area can be approximately <NUM>% of the lower overall area.

As illustrated in <FIG>, either or both of the upper outer surface <NUM> and the lower outer surface <NUM> can define a respective convexity. For instance, the upper outer surface <NUM> can define a convexity as it extends along one or both of the lateral direction A and the longitudinal direction L. Thus, the upper outer surface <NUM> can define a lateral convexity as it extends along the lateral direction A from one of the first and second side walls <NUM> and <NUM> to the other of the first and second side walls <NUM> and <NUM>. For instance, the upper outer surface <NUM> can be curved from the first side wall <NUM> to the second side wall <NUM>. The lateral convexity defined by the upper outer surface <NUM> can be disposed at the leading end <NUM>, alternatively or additionally at the trailing end <NUM>, and alternatively or additionally at a location between the leading end <NUM> to the trailing end <NUM>. For instance, the convexity of the upper outer surface <NUM> can extend from the leading end <NUM> to the trailing end <NUM>. Alternatively, the upper outer surface <NUM> can be substantially planar as it extends along the lateral direction from the first side wall <NUM> to the second side wall. Further, the upper outer surface <NUM> can define a longitudinal convexity as it extends along the longitudinal direction L from one of the leading end <NUM> and the trailing end <NUM> to the other of the leading end <NUM> and the trailing end <NUM>. For instance, the upper outer surface <NUM> can be curved from the leading end <NUM> to the trailing end <NUM>. Alternatively, the upper outer surface <NUM> can be substantially planar as it extends along the longitudinal direction L from the leading end <NUM> to the trailing end <NUM>.

Similarly, the lower outer surface <NUM> can define a convexity as it extends along one or both of the lateral direction A and the longitudinal direction L. Thus, the lower outer surface <NUM> can define a lateral convexity as it extends along the lateral direction A from one of the first and second side walls <NUM> and <NUM> to the other of the first and second side walls <NUM> and <NUM>. For instance, the lower outer surface <NUM> can be curved from the first side wall <NUM> to the second side wall <NUM>. The lateral convexity defined by the lower outer surface <NUM> can be disposed at the leading end <NUM>, alternatively or additionally at the trailing end <NUM>, and alternatively or additionally at a location between the leading end <NUM> to the trailing end <NUM>. For instance, the convexity of the lower outer surface <NUM> can extend from the leading end <NUM> to the trailing end <NUM>. Alternatively, the lower outer surface <NUM> can be substantially planar as it extends along the lateral direction from the first side wall <NUM> to the second side wall. Further, the lower outer surface <NUM> can define a longitudinal convexity as it extends along the longitudinal direction L from one of the leading end <NUM> and the trailing end <NUM> to the other of the leading end <NUM> and the trailing end <NUM>. For instance, the lower outer surface <NUM> can be curved from the leading end <NUM> to the trailing end <NUM>. Alternatively, the lower outer surface <NUM> can be substantially planar as it extends along the longitudinal direction L from the leading end <NUM> to the trailing end <NUM>.

Referring now to <FIG>, in one example the intervertebral implant <NUM> can define a lordotic profile. In particular, one or both of the upper and lower outer surfaces <NUM> and <NUM> can be sloped with respect to each other as they extend from the first side wall <NUM> to the second side wall <NUM>. For instance, the fist side wall <NUM> can be taller than the second side wall <NUM> along the transverse direction such that the implant <NUM>. For instance, the first side wall <NUM> can have a first height along the transverse direction T that defines the height of the implant <NUM>. The second side wall <NUM> can have a second height along the transverse direction T that is less than the first height. Because the second side wall <NUM> is disposed posterior of the first side wall <NUM> when the implant <NUM> is disposed in the intervertebral disc space <NUM>, the second height can be referred to as a posterior height of the implant <NUM>. It should be appreciated that the first and second heights can be configured such that the upper and lower outer surfaces <NUM> and <NUM> taper toward each other in a direction from the first side wall <NUM> to the second side wall <NUM>. The tapered upper and lower outer surfaces <NUM> and <NUM> can define a lordotic profile that the implant <NUM> can impart onto the first and second vertebral bodies <NUM> and <NUM>.

The lordotic profile can be configured as a lordotic angle defined by one or both of the first and second endplates <NUM> and <NUM>, respectively. In this regard, it should be appreciated that the first side wall <NUM> can have a height greater than that of the posterior side <NUM> wall along the transverse direction T. Thus, the upper and lower endplates <NUM> and <NUM> define the lordotic angle with respect to each other as they extend along the lateral direction A. In particular, the lordotic profile can be at least partially defined the upper outer surface <NUM> that extends from the first side wall <NUM> to the second side wall <NUM>. Further, the lordotic angle can be at least partially defined by the lower surface <NUM> that extends from the first side wall <NUM> to the second side wall <NUM>. Thus, the lordotic profile can be configured as a lordotic angle defined by one or both of the upper and lower outer surfaces <NUM> and <NUM>. The upper and lower outer surfaces <NUM> and <NUM> can define any suitable lorditic angle with respect to each other as desired as they extend in a direction from the first side wall <NUM> to the second side wall <NUM>.

In one example, whether the upper and lower outer surfaces <NUM> and <NUM> are planar or non-planar, the angle can be defined by an upper straight line that extends from the uppermost end of the first side wall <NUM> to the uppermost end of the second side wall <NUM>, and a lower straight line that extends from the lowermost end of the first side wall <NUM> to the lowermost end of the second side wall <NUM>. Thus, the upper straight line can extend at least generally along the upper endplate <NUM>. The lower straight line can extend at least generally along the lower endplate <NUM>. The upper and lower straight lines can lie in a common plane that is defined by the transverse direction T and the lateral direction A. The uppermost ends of the first and second side walls <NUM> and <NUM> can define intersections with the upper endplate <NUM>. The lowermost ends of the first and second side walls <NUM> and <NUM> can define intersections with the lower endplate <NUM>. In one example, the lordotic angle can be approximately <NUM> degrees. It should be appreciated, of course, that the lordotic angle can be any suitable lordotic angle as desired. The term "approximate" or "substantial" as used herein with respect to measurements and directions recognizes that variations can be due, for instance, to manufacturing tolerances.

The intervertebral implant <NUM> can be configured to be attached to an insertion instrument that is configured to drive the implant <NUM> into the intervertebral space <NUM>. For instance, the implant <NUM> can include an attachment hole <NUM> that is configured to receive an attachment rod of the insertion instrument. The attachment hole <NUM> can extend into the trailing end <NUM> in the insertion direction. Thus, the attachment hole <NUM> can extend into the trailing end <NUM> in a direction toward the leading end <NUM>. The attachment hole <NUM> can be internally threaded so as to threadedly mate with a threaded attachment rod of the insertion instrument.

Alternatively or additionally, the implant <NUM> can include at least one attachment pocket <NUM> that is configured to receive a complementary attachment arm of an insertion instrument. In particular, the implant <NUM> can include first and second attachment pockets <NUM> that are spaced from each other along the lateral direction A. The first and second attachment pockets <NUM> can extend into the trailing end <NUM> in the insertion direction, and can also extend into the first and second side walls <NUM> and <NUM>, respectively, along the lateral direction A. Thus, the first and second attachment pockets <NUM> can be open to both the trailing end <NUM> and to the first and second side walls <NUM> and <NUM>, respectively. The first and second attachment pockets <NUM> can extend into the first and second side walls <NUM> and <NUM>, respectively, to respective first and second inner surfaces <NUM> of the implant <NUM>. The attachment hole <NUM> can be disposed between the first and second attachment pockets <NUM> with respect to the lateral direction A. Thus, the attachment hole <NUM> can be disposed between the first and second inner surfaces <NUM> that at least partially define the first and second pockets <NUM>, respectively. The inner surfaces <NUM> can be scalloped or can define any suitable texture to assist in engagement with the respective attachment arms of the insertion instrument.

In one example, the implant <NUM> can engage the insertion instrument as in the Oracle® Cage system. In another example, the implant <NUM> can engage the insertion instrument as in the Cougar® LS implant system from DePuy Synthes, Inc, a company of Johnson and Johnson having a place of business in New Brunswick, NJ. It should further be appreciated that the implant <NUM> can attach to an insertion instrument that does not attach to the implant <NUM> in the attachment hole <NUM>. Such instruments are described in <CIT>. For instance, the insertion instrument can include a pusher member that abuts the trailing end of the implant <NUM>, and further includes first and second arms that extend into the first and second attachment pockets <NUM>. The pusher member can apply a force that urges the implant <NUM> to translate between upper and lower arms of the insertion instrument and into the intervertebral space <NUM>. As is the case with the insertion instruments discloser herein, once the implant <NUM> is disposed in the intervertebral space <NUM> at the desired position in the desired location, the insertion instrument can be detached from the implant <NUM>.

In this regard, an implant kit can include the implant <NUM> and the insertion instrument. Method steps for inserting the intervertebral implant <NUM> into the intervertebral space <NUM> in the manner described above are also contemplated by the present disclosure.

Referring now also to <FIG> generally, it is recognized that a kit of intervertebral implants <NUM> can be provided. The intervertebral implant <NUM> described above with respect to <FIG> can be provided as a first intervertebral implant of the kit. <FIG> illustrate a second intervertebral implant <NUM>' of the kit. <FIG> illustrate a third intervertebral implant <NUM>" of the kit. It should be appreciated that the kit can include any number of intervertebral implants as desired, and that the intervertebral implants <NUM>, <NUM>', and <NUM>" are merely representative of intervertebral implants that can be included in the kit. The second and third intervertebral implants <NUM>' and <NUM>'' can be constructed as described above with respect to <FIG> unless otherwise indicated. Accordingly, the second intervertebral implant <NUM>' as illustrated in <FIG> include second components identified with reference numbers in common with like components of the first intervertebral implant <NUM> illustrated in <FIG> which can be designated as first components, but bearing an apostrophe. Similarly, the third intervertebral implant <NUM>'' as illustrated in <FIG> include third components identified with reference numbers in common with like first components of the first intervertebral implant <NUM> illustrated in <FIG>, but bearing a double apostrophe.

One or more of the intervertebral implants of the kit can define a lordotic angle that is greater than one or more others of the intervertebral implants of the kit. For instance, referring now to <FIG>, the second intervertebral implant <NUM>' can have a second lordotic profile that is different than the lordotic profile of the first intervertebral implant <NUM>. In this regard, the lordotic profile of the first intervertebral implant <NUM> can be referred to as a first lordotic profile. Similarly, the lordotic angle defined by the upper and lower outer surfaces <NUM> and <NUM> of the first intervertebral implant <NUM> can be referred to as a first lordotic angle.

In one example, the second lordotic profile can be configured as a second lordotic angle defined by one or both of the first and second endplates <NUM>' and <NUM>' as described above with respect to the first intervertebral implant <NUM>. Thus, the second lordotic profile can be configured as a second lordotic angle defined by one or both of the upper and lower outer surfaces <NUM>' and <NUM>'. In particular, the upper and lower outer surfaces <NUM>' and <NUM>' can define any suitable angle with respect to each other as desired as they extend in a direction from the respective first side wall <NUM>' to the respective second side wall <NUM>'. As described above with respect to the first intervertebral implant <NUM>, whether the upper and lower outer surfaces <NUM>' and <NUM>' are planar or non-planar, the lordotic angle can be defined by an upper straight line that extends from the uppermost end of the first side wall <NUM>' to the uppermost end of the second side wall <NUM>', and a lower straight line that extends from the lowermost end of the first side wall <NUM>' to the lowermost end of the second side wall <NUM>'. In one example, the second lordotic angle can be approximately <NUM> degrees. It should be appreciated, of course, that the second lordotic angle can be any suitable lordotic angle as desired. In one example, the second lordotic angle can be greater than the first lordotic angle. Further, a plurality of the intervertebral implants of the kit can define lordotic angles greater than the first lordotic angle. Alternatively, the second lordotic angle can be less than the first lordotic angle. Further, a plurality of the intervertebral implants of the kit can define lordotic angles greater than the first lordotic angle.

Referring now to <FIG>, the third intervertebral implant <NUM>" of the kit can be devoid of a lordotic profile. In particular, the first and second endplates <NUM>" and <NUM>" of the third intervertebral implant <NUM>" can be configured so as to not define a lordotic angle. Thus, the upper and lower outer surfaces <NUM>' and <NUM>' can be oriented substantially parallel to each other as they extend along the lateral direction A. Thus, the first and second side walls <NUM> and <NUM> can define the same height along the transverse direction T. As a result, the uppermost ends of the first and second side walls <NUM> and <NUM> can be aligned with each other along the lateral direction A. Similarly, the lowermost ends of the first and second side walls <NUM> and <NUM> can be aligned with each other along the lateral direction. Accordingly, an upper straight line that extends from the uppermost end of the first side wall <NUM> to the uppermost end of the second side wall <NUM> can be oriented parallel with a lower straight line that extends from the lowermost end of the first side wall <NUM> to the lowermost end of the second side wall <NUM> Further, it should be appreciated that a plurality of the intervertebral implants of the kit can be devoid of a lordotic angle.

It is recognized that the endplates made of Titanium have a hardness that is greater than the hardness of endplates made of PEEK. Accordingly, it is desirable to avoid increasing the thickness of the endplates <NUM> and <NUM> to a degree such that the endplates <NUM> and <NUM> become too stiff. Accordingly, at least respective portions of the first endplates <NUM> and <NUM> of the first intervertebral implant <NUM>, the second endplates <NUM>' and <NUM>' of the second intervertebral implant <NUM>', and the third endplates <NUM>" and <NUM>" of the third intervertebral implant <NUM>" can have the same thickness. The respective thicknesses of the endplates <NUM> and <NUM> can be measured along the transverse direction T. In one example, the respective upper thicknesses of the first upper endplate <NUM>, the second upper endplate <NUM>', and the third upper endplate <NUM>" can be substantially equal to each other, regardless of the lordotic profile or lack thereof of the respective intervertebral implant. Similarly, the respective lower thicknesses of the first lower endplate <NUM>, the second lower endplate <NUM>', and the third lower endplate <NUM>" can be substantially equal to each other, regardless of the lordotic profile or lack thereof of the respective intervertebral implant. Further, the respective upper and lower thicknesses can be constant along a substantial entirety of the respective endplates. Further still, the upper thickness can be substantially equal to the lower thickness.

The upper and lower thicknesses can be measured at an intersection with the respective upper and lower endplates and the respective anterior side walls. As described above, the implants can include side apertures <NUM>, <NUM>', and <NUM>'', respectively, that extend through the respective first side walls <NUM>, <NUM>', and <NUM>". The thickness of the upper and lower endplates can be measured at a location that is aligned with the respective side aperture that extends through the respective first side wall (also referred to as an anterior side aperture). The thicknesses can be measured from the outer surface of the respective endplate to the inner surface of the respective endplate along the transverse direction T.

The height of the first side wall <NUM>' of the second intervertebral implant <NUM>' can be greater than the height of the first side wall <NUM> of the first intervertebral implant <NUM>. However, because the upper endplates <NUM> and <NUM>' have the same thickness, and the lower endplates <NUM> and <NUM>' have the same thickness, the first and second side apertures <NUM> and <NUM>' can have different heights. In particular, the side aperture <NUM>' of the second intervertebral implant <NUM>' that extends through the anterior side wall <NUM>' can have a second height along the transverse direction T that is greater than a first height of the side aperture <NUM> of the first intervertebral implant that extends through the anterior side wall <NUM>. Thus, the anterior side aperture of the first intervertebral implant <NUM> can define a first area along the respective first side wall <NUM>, and the anterior side aperture of the second intervertebral implant <NUM>' can define a second area along the respective side wall <NUM>' that is greater than the first area. Similarly, the third side aperture <NUM>" of the third intervertebral implant <NUM>" that extends through the anterior side wall <NUM>" can have a third height along the transverse direction T that is less than the first height of the side aperture <NUM> of the first intervertebral implant <NUM>. Thus, the anterior side aperture of the third intervertebral implant <NUM>" can define a third area along the respective side wall <NUM>" that is less than the first area along of the first intervertebral implant <NUM>.

As described above, the lordotic profile of each of the implants of the kit can be the same or different than one or more other intervertebral implants of the kit. Alternatively or additionally, one or more the intervertebral implants <NUM> of the kit can be sized differently than each other. For instance, one or more of the intervertebral implants <NUM> of the kit have a length along the longitudinal direction L that is than one or more others of the intervertebral implants <NUM> of the kit. The length can be measured from the respective leading end to the respective trailing end along the longitudinal direction. By way of example, the lengths of the intervertebral implants of the kit can be in the range between and including approximately <NUM> and approximately <NUM>, including approximately <NUM>, approximately <NUM>, approximately <NUM>, approximately <NUM>, and approximately <NUM>. It should be appreciated, of course, that the intervertebral implants of the kit can have any suitable length as desired. Alternatively or additionally, one or more of the intervertebral implants <NUM> of the kit can have a width along the lateral direction A that is greater than the others of the intervertebral implants <NUM> of the kit. The width can be measured from the respective first side wall to the respective second side wall along the lateral direction A. By way of example, the widths of the intervertebral implants of the kit can be in the range between and including approximately <NUM> and approximately <NUM>, including approximately <NUM> and approximately <NUM>. It should be appreciated, of course, that the intervertebral implants of the kit can have any suitable width as desired.

Claim 1:
First and second intervertebral implants (<NUM>, <NUM>', <NUM>") each configured to be inserted into an intervertebral space (<NUM>), each of the first and second intervertebral implants comprising:
a leading end (<NUM>) and a trailing end (<NUM>), arranged such that the leading end is spaced from the trailing end in an insertion direction (L) into the intervertebral space;
an anterior side wall (<NUM>) and a posterior side wall (<NUM>) each extending between the leading end and the trailing end, wherein the anterior and posterior side walls are opposite each other along a lateral direction (A) that is perpendicular to the insertion direction; and
upper and lower endplates (<NUM>, <NUM>) each made of Titanium or an alloy thereof and spaced from each other along a transverse direction (T) that is perpendicular to each of the insertion direction and the lateral direction, each of the endplates defining a respective outer surface (<NUM>, <NUM>) that is configured to abut respective superior and inferior vertebral bodies (<NUM>, <NUM>) when the implant is disposed in the intervertebral space,
wherein the anterior side wall (<NUM>) of the first intervertebral implant (<NUM>) has a height greater than that of the posterior side wall (<NUM>) along the transverse direction (T), such that the upper and lower endplates (<NUM>, <NUM>) of the first intervertebral implant define a first angle with respect to each other as they extend along the lateral direction (A), and each of the upper and lower endplates of the first intervertebral implant define respective thicknesses at the anterior side wall, and
wherein the anterior side wall (<NUM>') of the second intervertebral implant (<NUM>') has a height greater than that of the posterior side wall (<NUM>') along the transverse direction (T), such that the upper and lower endplates (<NUM>', <NUM>') of the second intervertebral implant define a second angle with respect to each other as they extend along the lateral direction (A) that is greater than the first angle, and each of the upper and lower endplates of the second intervertebral implant define respective thicknesses at the anterior side wall that are equal to the respective thicknesses of the upper and lower endplates (<NUM>, <NUM>) of the first intervertebral implant (<NUM>) at the anterior side wall.