Patent Description:
The present disclosure relates to implantable orthopedic devices, and more particularly to implantable devices for stabilizing the spine. Even more particularly, the present disclosure relates to intervertebral cages comprising integrated expansion and angular adjustment mechanisms that allow expansion of the cages from a first, insertion configuration having a reduced size to a second, implanted configuration having an expanded size. The intervertebral cages are able to adjust angularly, and adapt to lordotic angles, particularly larger lordotic angles, while restoring sagittal balance and alignment of the spine.

The use of fusion-promoting interbody implantable devices, often referred to as cages or spacers, is well known as the standard of care for the treatment of certain spinal disorders or diseases. For example, in one type of spinal disorder, the intervertebral disc has deteriorated or become damaged due to acute injury or trauma, disc disease or simply the natural aging process. A healthy intervertebral disc serves to stabilize the spine and distribute forces between vertebrae, as well as cushion the vertebral bodies. A weakened or damaged disc therefore results in an imbalance of forces and instability of the spine, resulting in discomfort and pain. The standard treatment today may involve surgical removal of a portion, or all, of the diseased or damaged intervertebral disc in a process known as a partial or total discectomy, respectively. The discectomy is often followed by the insertion of a cage or spacer to stabilize this weakened or damaged spinal region. This cage or spacer serves to reduce or inhibit mobility in the treated area, in order to avoid further progression of the damage and/or to reduce or alleviate pain caused by the damage or injury. Moreover, these types of cages or spacers serve as mechanical or structural scaffolds to restore and maintain normal disc height, and in some cases, can also promote bony fusion between the adjacent vertebrae.

However, one of the current challenges of these types of procedures is the very limited working space afforded the surgeon to manipulate and insert the cage into the intervertebral area to be treated. Access to the intervertebral space requires navigation around retracted adjacent vessels and tissues such as the aorta, vena cava, dura and nerve roots, leaving a very narrow pathway for access. The opening to the intradiscal space itself is also relatively small. Hence, there are physical limitations on the actual size of the cage that can be inserted without significantly disrupting the surrounding tissue or the vertebral bodies themselves. In this context, <CIT>, <CIT>, and <CIT> disclose exemplary expandable intervertebral cages that allow for both height and angular adjustment of their endplates.

Further complicating the issue is the fact that the vertebral bodies are not positioned parallel to one another in a normal spine. There is a natural curvature to the spine due to the angular relationship of the vertebral bodies relative to one another. The ideal cage must be able to accommodate this angular relationship of the vertebral bodies, or else the cage will not sit properly when inside the intervertebral space. An improperly fitted cage would either become dislodged or migrate out of position, and lose effectiveness over time, or worse, further damage the already weakened area.

Thus, it is desirable to provide intervertebral cages or spacers that not only have the mechanical strength or structural integrity to restore disc height or vertebral alignment to the spinal segment to be treated, but also be configured to easily pass through the narrow access pathway into the intervertebral space, and then accommodate the angular constraints of this space, particularly for larger lordotic angles.

The present disclosure describes spinal implantable devices that address the aforementioned challenges and meet the desired objectives. The present invention relates to an expandable intervertebral cage as claimed hereafter. Other embodiments of the invention are set forth in the dependent claims. These spinal implantable devices, or more specifically intervertebral cages or spacers, are configured to be expandable as well as angularly adjustable. The cages comprise upper and lower plates for bearing against endplates of the vertebral bodies, and have integrated expansion and angular adjustment mechanisms that allow the cage to change size and angle as needed, with little effort. In some embodiments, the cages may have a first, insertion configuration characterized by a reduced insertion size to facilitate insertion through a narrow access passage and into the intervertebral space. The cages may be inserted in the first configuration and once the cage is implanted, the
cage can be expanded to a second configuration having a larger size than the insertion size. In their second configuration, the cages are able to maintain the proper disc height and stabilize the spine by restoring sagittal balance and alignment. Additionally, the intervertebral cages are configured to be able to adjust the angle of lordosis, and can accommodate larger lordotic angles, as well as provide pure expansion only (i.e., height adjustment), or a combination of both angular and height adjustment, in their second, expanded configuration. Further, these cages may promote fusion to further enhance spine stability by immobilizing the adjacent vertebral bodies.

According to one aspect of the disclosure, the cages may be manufactured using selective laser melting (SLM) techniques, a form of additive manufacturing. The cages may also be manufactured by other comparable techniques, such as for example, 3D printing, electron beam melting (EBM), layer deposition, and rapid manufacturing. With these production techniques, it is possible to create an all-in-one, multi-component device which may have interconnected and movable parts without further need for external fixation or attachment elements to keep the components together. Accordingly, the intervertebral cages of the present disclosure are formed of multiple, interconnected parts that do not require additional external fixation elements to keep together.

Even more relevant, cages manufactured in this manner would not have connection seams whereas devices traditionally manufactured would have joined seams to connect one component to another. These connection seams can often represent weakened areas of the implantable device, particularly when the bonds of these seams wear or break over time with repeated use or under stress. By manufacturing the disclosed implantable devices using additive manufacturing, one of the advantages is that connection seams are avoided entirely and therefore the problem is avoided.

Another advantage of the present devices is that, by manufacturing these devices using an additive manufacturing process, all of the components of the device remain a complete construct during both the insertion process as well as the expansion process. That is, multiple components are provided together as a collective single unit so that the collective single unit is inserted into the patient, actuated to allow expansion, and then allowed to remain as a collective single unit in situ. In contrast to other cages requiring insertion of external screws or wedges for expansion, in the present embodiments the expansion and blocking components do not need to be inserted into the cage, nor removed from the cage, at any stage during the process. This is because these components are manufactured so as to be captured internally within the cages, and while freely movable within the cage, are already contained within the cage so that no additional insertion or removal is necessary.

In some embodiments, the cages can have an engineered cellular structure on a portion of, or over the entirety of, the cage. This cellular structure can include a network of pores, microstructures and nanostructures to facilitate osteosynthesis. For example, the engineered cellular structure can comprise an interconnected network of pores and other micro and nano sized structures that take on a mesh-like appearance. These engineered cellular structures can be provided by etching or blasting, to change the surface of the device on the nano level. One type of etching process may utilize, for example, HF acid treatment.

In addition, these cages can also include internal imaging markers that allow the user to properly align the device and generally facilitate insertion through visualization during navigation. The imaging marker shows up as a solid body amongst the mesh under x-ray, fluoroscopy or CT scan, for example.

Another benefit provided by the implantable devices of the present disclosure is that they can be specifically customized to the patient's needs. Customization of the implantable devices is relevant to providing a preferred modulus matching between the implant device and the various qualities and types of bone being treated, such as for example, cortical versus cancellous, apophyseal versus central, and sclerotic versus osteopenic bone, each of which has its own different compression to structural failure data. Likewise, similar data can also be generated for various implant designs, such as for example, porous versus solid, trabecular versus non-trabecular, etc. Such data may be cadaveric, or computer finite element generated. Clinical correlation with, for example, DEXA data can also allow implantable devices to be designed specifically for use with sclerotic, normal, or osteopenic bone. Thus, the ability to provide customized implantable devices such as the ones provided herein allow the matching of the Elastic Modulus of Complex Structures (EMOCS), which enable implantable devices to be engineered to minimize mismatch, mitigate subsidence and optimize healing, thereby providing better clinical outcomes.

In one exemplary embodiment, an expandable spinal implant is provided. The expandable spinal implant comprises a housing comprising an upper housing portion and a lower housing portion. The upper housing portion includes an upper plate configured for placement against an endplate of a first vertebral body. The lower housing portion includes a lower plate configured for placement against an endplate of a second, adjacent vertebral body. The upper housing portion further includes upper sidewalls that extend from the upper plate. The lower housing portion further includes lower sidewalls that extend from the lower plate. The upper and lower sidewalls may be configured to slide along one another.

The expandable spinal implant further includes an expansion and angular adjustment mechanism within the housing that is configured to effect angular adjustment, height adjustment, or a combination of both, of the spinal implant. The expansion and angular adjustment mechanism comprises a pair of wedges located at opposite ends of the housing, each wedge having a bearing surface for urging against the sidewalls of the upper and lower plates. In addition, the expansion and angular adjustment mechanism further includes a driver component connecting the wedges together and being configured to pull the wedges towards one another upon actuation.

Each of the upper and lower sidewalls may have a sloped profile. The housing may further include one or more deformable strips for controlling expansion of the intervertebral cage. The bearing surfaces of the wedges may comprise convex surfaces. The wedges may include a central opening for receiving the driver component therethrough. The driver component may include a tool-engaging member configured to couple to a tool to actuate the driver component. For instance, the driver can include an opening for receiving the tool to actuate the driver component. The expansion and angular adjustment mechanism is intended to be freely held within the housing.

In another exemplary embodiment, an expandable spinal implant is provided. The expandable spinal implant comprises a housing comprising an upper plate configured for placement against an endplate of a first vertebral body, the upper plate having upper sidewalls extending therefrom, and a lower plate configured for placement against an endplate of a second, adjacent vertebral body, the lower plate having lower sidewalls extending therefrom.

The expandable spinal implant further includes an expansion and angular adjustment mechanism within the housing and be configured to effect angular adjustment, height adjustment, or a combination of both, of the spinal implant. The expansion and angular adjustment mechanism comprises a pair of wedges located at opposite ends of the housing. Each wedge may have slots on a lower surface for translation along guide rails on the lower plate, such that movement of the wedges causes distraction or angulation of the plates relative to one another.

The wedges may have slots that are configured to receive projections of the upper housing portion to urge the upper plate away from the lower plate. The lower plate may further include elastically deformable strips extending from the lower sidewalls. The bearing surfaces of the wedges may comprise angled surfaces. The wedges may each include a tool-engaging opening. The upper plate may comprise rounded pins for engaging the elastically deformable strips of the lower plate, and further include rounded protrusions on an interior of the sidewalls, the rounded protrusions engaging the slots on the upper surface of the wedges. The slots on the upper surface of the wedges may be angled.

According to one aspect of the exemplary embodiment, the expandable spinal implant may comprise a porous structure located on the upper plate. According to another aspect, the porous structure may be located on the lower plate. In some embodiments, an elastically deformable screen may be provided extending between the upper and lower plates. In addition, teeth may be provided on the lower plate for enhanced anchorage to bone.

In some embodiments, the guide rails may comprise teeth. The wedges may further include click fingers for engaging the teeth of the guide rails. The wedges may be independently movable relative to one another, such that movement of one of the wedges effects angular displacement of the upper plate.

In yet another exemplary embodiment, an expandable spinal implant is provided. The expandable spinal implant comprises a housing comprising an upper plate configured for placement against an endplate of a first vertebral body, and a lower plate configured for placement against an endplate of a second, adjacent vertebral body. The upper housing portion and lower housing portion may each have sidewalls that extend from the upper plate and lower plate, respectively, with each of the sidewalls including a set of projections, such as knobs. The housing may further include a set of brackets. Each bracket may be affixed to an actuator rod that extends out of an end of the housing. The housing may further include a vertical slot that is configured to receive a projection from each of the upper and lower plates. The projections of the sidewalls may reside within angled slots of the bracket. In use, pulling one of the rods effects movement of the knobs relative to the angled slots, which causes angular adjustment of the plates relative to the housing.

According to an aspect of the present disclosure, each of the sidewalls may include a set of projections that can be configured as knobs. Each of the actuator rods may be configured to horizontally translate in one direction only. The housing may include a top opening to allow the upper plate to extend out of the housing upon expansion, and a bottom opening to allow the lower plate to extend out of the housing upon expansion. The rods can be configured to be independently movable. Additionally, each bracket comprises a pair of angled slots, the angled slots being angled away from one another.

Although the following discussion focuses on spinal implants, it will be appreciated that many of the principles may equally be applied to other structural body parts requiring bone repair or bone fusion within a human or animal body, including other joints such as knee, shoulder, ankle or finger joints.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure. Additional features of the disclosure will be set forth in part in the description which follows or may be learned by practice of the disclosure.

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the disclosure and together with the description, serve to explain the principles of the disclosure.

The present disclosure provides various spinal implant devices, such as interbody fusion spacers, or cages, for insertion between adjacent vertebrae. The devices can be configured for use in either the cervical or lumbar region of the spine. In some embodiments, these devices may be configured as ALIF cages, or LLIF cages. However, it is contemplated that the principles of this disclosure may be equally utilized in transforaminal lumbar interbody fusion (TLIF) devices, posterior lumbar interbody fusion (PLIF) cages, and oblique lumbar interbody fusion (OLIF) cages.

These cages can restore and maintain intervertebral height of the spinal segment to be treated, and stabilize the spine by restoring sagittal balance and alignment. In some embodiments, the cages may have integrated expansion and angular adjustment mechanisms that allow the cage to change height and angle as needed, with little effort. The cages may have a first, insertion configuration characterized by a first or reduced size or height to facilitate insertion through a narrow access passage and into the intervertebral space. In some examples, the first or reduced height can define the minimum height achievable by the cages. The cages may be inserted in the first, insertion configuration, and then expanded to a second, expanded configuration once implanted. The second, expanded configuration can be characterized by a second or increased size or height that is greater than the first or reduced size or height. In their second configuration, the cages are able to maintain the proper disc height and stabilize the spine by restoring sagittal balance and alignment. Additionally, the plates of the intervertebral cages that contact the vertebral endplates are angularly adjustable. Thus, the intervertebral cages configured to be able to adjust the angle of lordosis or kyphosis, and can accommodate larger lordotic or kyphotic angles in their second, expanded configuration. In this regard, reference to lordotic angles when the cages are configured for implantation into the lumbar region of the spine can equally apply to kyphotic angles when the cages are configured for implantation into the cervical region of the spine. Further, these cages may promote fusion to further enhance spine stability by immobilizing the adjacent vertebral bodies.

Additionally, the implantable devices may be manufactured using selective laser melting (SLM) techniques, a form of additive manufacturing. The devices may also be manufactured by other comparable techniques, such as for example, 3D printing, electron beam melting (EBM), layer deposition, and rapid manufacturing. With these production techniques, it is possible to create an all-in-one, multi-component device which may have interconnected and movable parts without further need for external fixation or attachment elements to keep the components together. Accordingly, the intervertebral cages of the present disclosure are formed of multiple, interconnected parts that do not require additional external fixation elements to keep together.

Thus, devices manufactured in this manner would not have connection seams whereas devices traditionally manufactured would have joined seams to connect one component to another. These connection seams can often represent weakened areas of the implantable device, particularly when the bonds of these seams wear or break over time with repeated use or under stress. By manufacturing the disclosed implantable devices using additive manufacturing, connection seams are avoided entirely and therefore the problem is avoided.

In addition, by manufacturing these devices using an additive manufacturing process, all of the internal components of the device remain a complete construct during both the insertion process as well as the expansion process. That is, multiple components are provided together as a collective single unit so that the collective single unit is inserted into the patient, actuated to allow expansion, and then allowed to remain as a collective single unit in situ. In contrast to other cages requiring insertion of external screws or wedges for expansion, in the present embodiments the expansion and blocking components do not need to be inserted into the cage, nor removed from the cage, at any stage during the process. This is because these components are manufactured so as to be captured internally within the cages, and while freely movable within the cage, are already contained within the cage so that no additional insertion or removal is necessary.

In addition, these cages can also include internal imaging markers that allow the user to properly align the cage and generally facilitate insertion through visualization during navigation. The imaging marker shows up as a solid body amongst the mesh under x-ray, fluoroscopy or CT scan, for example,.

Another benefit provided by the implantable devices of the present disclosure is that they can be specifically customized to the patient's needs. Customization of the implantable devices is relevant to providing a preferred modulus matching between the implant device and the various qualities and types of bone being treated, such as for example, cortical versus cancellous, apophyseal versus central, and sclerotic versus osteopenic bone, each of which has its own different compression to structural failure data. Likewise, similar data can also be generated for various implant designs, such as for example, porous versus solid, trabecular versus non-trabecular, etc. Such data may be cadaveric, or computer finite element generated. Clinical correlation with, for example, DEXA data can also allow implantable devices to be designed specifically for use with sclerotic, normal, or osteopenic bone. Thus, the ability to provide customized implantable devices such as the ones provided herein allow the matching of the Elastic Modulus of Complex Structures (EMOCS), which enable implantable devices to be engineered to minimize mismatch, mitigate subsidence and optimize healing, thereby providing better clinical outcomes. It should be appreciated throughout the description below that the features, structures, and methods described with respect to one example of an intervertebral cage can be applied to all other examples of intervertebral cages unless indicated to the contrary.

Turning now to the drawings, <FIG> illustrate one example of an expandable and angularly adjustable intervertebral cage <NUM> of the present disclosure. <FIG> show the intervertebral cage <NUM> in its first or insertion configuration. The insertion configuration can also be referred to as an unexpanded configuration. The intervertebral cage <NUM> includes a housing <NUM> that is defined by a superior or upper housing portion <NUM> and an inferior or lower housing portion <NUM>. The upper housing portion <NUM> can include a superior or upper plate <NUM>, and the lower housing portion <NUM> can include an inferior or lower plate <NUM>. The upper and lower plates <NUM> and <NUM>, respectively, are configured for placement against respective superior and inferior vertebral bodies. For instance, the upper plate <NUM> can define an outer or upper bearing surface <NUM> that is configured to abut an endplate of the superior vertebral body. Similarly, the lower plate <NUM> can define an outer or lower bearing surface <NUM> that is configured to abut an endplate of the inferior vertebral body. The upper and lower bearing surfaces <NUM> and <NUM> are spaced from each other along a transverse direction T. In one example, the bearing surfaces <NUM> and <NUM> can be flat for placement against the endplates. It is understood, of course, that the bearing surfaces <NUM> and <NUM> may also be sloped as desired. For instance, the bearing surfaces <NUM> and <NUM> can be convex and rounded if desired. Further, the upper and lower bearing surfaces <NUM> and <NUM> can be defined by flexible slates that are spaced from each other along the lateral direction A, and elongate along the longitudinal direction L.

The intervertebral cage <NUM> can define a first, leading end <NUM> with respect to insertion into an intervertebral disc space defined between the superior and inferior vertebrae. The intervertebral cage <NUM> can further define a second, trailing end <NUM> opposite the leading end <NUM> along a longitudinal direction L. The longitudinal direction L can be oriented perpendicular to the transverse direction T. Thus, the intervertebral cage <NUM> can define a leading direction that extends from the trailing end <NUM> toward the leading end <NUM>. Thus, leading components of the intervertebral cage <NUM> can be spaced from trailing components of the intervertebral cage in the leading direction. The intervertebral cage <NUM> can similarly define a trailing direction that extends from the leading end <NUM> toward the trailing end <NUM>.

The upper housing portion <NUM> can further include upper sidewalls <NUM> that extend from the upper plate <NUM>. For instance, the upper sidewalls <NUM> can extend down from the upper plate <NUM> along the transverse direction T. The upper sidewalls <NUM> can be spaced from each other along a lateral direction A. The lateral direction A can be oriented perpendicular to each of the longitudinal direction L and the transverse direction T. In one example, the transverse direction T can define a vertical direction during use. The lateral and longitudinal directions A and L can define horizontal directions during use. The lower housing portion <NUM> can include lower sidewalls <NUM> that extend from the lower plate <NUM>. For instance, the lower sidewalls <NUM> can extend up from the lower plate <NUM> along the transverse direction T. The lower sidewalls <NUM> can be spaced from each other along the lateral direction A. The upper and lower sidewalls <NUM> and <NUM> can be configured to slide along one another. Thus, the upper and lower plates <NUM> and <NUM> can be translatable and rotatable in relation to each other vertically.

The upper and lower housing portions <NUM> and <NUM> can be sloped. That is, the upper and lower housing portions <NUM> and <NUM> can define upper and lower sloped engagement surfaces <NUM> and <NUM>, respectively (see <FIG>). For instance, one of the upper sloped engagement surfaces <NUM> can be a leading upper sloped engagement surface, and the other of the upper sloped engagement surface <NUM> can be a trailing upper sloped engagement surface. Similarly, one of the lower sloped engagement surfaces <NUM> can be a leading lower sloped engagement surface, and the other of the lower sloped engagement surface <NUM> can be a trailing lower sloped engagement surface. In one example, the upper and lower sloped engagement surfaces <NUM> and <NUM> can be defined by the upper and lower sidewalls <NUM> and <NUM>, respectively. For instance, the upper and lower sloped engagement surfaces <NUM> and <NUM> can be defined by longitudinally outermost surfaces of the upper and lower sidewalls <NUM> and <NUM>, respectively.

The engagement surfaces <NUM> and <NUM> can be angled, rounded, or otherwise angularly offset with respect to the transverse direction T as they extend in the longitudinal direction L. For instance, the leading engagement surfaces <NUM> and <NUM> can flare toward the trailing end as they extend away from the respective upper and lower plates <NUM> and <NUM>. Similarly, the trailing engagement surfaces <NUM> and <NUM> can flare toward the leading end as they extend away from the respective upper and lower plates <NUM> and <NUM>.

The intervertebral cage <NUM> can further include at least one elastically deformable strip <NUM> that is configured to control the movement of the upper and lower sidewalls <NUM> and <NUM>, respectively, relative to one another. The elastically deformable strips <NUM> can be attached to each of the upper housing portion <NUM> and the lower housing portion <NUM>. The elastically deformable strips <NUM> can have a spring constant that allows but resists movement of the upper and lower housing portions <NUM> and <NUM> relative to each other. In this regard, the elastically deformable strips <NUM> can be referred to as spring members that can be configured as strips or any suitable alternative configuration as desired. The elastically deformable strips <NUM> can be located outboard of the sidewalls <NUM> and <NUM> with respect to the lateral direction A, as shown in <FIG>.

The intervertebral cage <NUM> can further include an integrated expansion and angular adjustment mechanism that is fully integrated within the intervertebral cage <NUM>. The angular adjustment mechanism can be disposed between the upper and lower plates <NUM> and <NUM>, respectively. For instance, the angular adjustment mechanism can be disposed between the upper plate <NUM> and the lower plate <NUM> with respect to the transverse direction T. The angular adjustment mechanism can include a driver component <NUM> and at least one wedge <NUM>. For instance, the angular adjustment mechanism can include first and second wedges <NUM> and <NUM>, respectively. The first and second wedges <NUM> and <NUM> can be disposed opposite each other with respect to the longitudinal direction L. For instance, the first wedge <NUM> can be a leading wedge, and the second wedge <NUM> can be a trailing wedge. One or both of the wedges <NUM> and <NUM> can include an opening or bore <NUM> that receives the driver component <NUM>. In one example, the bore <NUM> is a central bore.

The driver component <NUM> can extend along a central axis. The central axis can extend along the longitudinal direction L. In one example, as descried in more detail below, the driver component <NUM> is configured to be actuated or driven so as to draw or pull at least one or both of the wedges <NUM> and <NUM> toward the other of the wedges <NUM> and <NUM>.

The wedges <NUM> and <NUM> can have outer engagement surfaces that can be angled, rounded, or otherwise angularly offset with respect to the transverse direction T as they extend in the longitudinal direction L. For instance, the engagement surfaces can be rounded convex surfaces. In one example, the leading wedge <NUM> can define upper and lower engagement surfaces flare toward the trailing wedge <NUM> as they extend away from the upper and lower plates <NUM> and <NUM>, respectively. In one example, the upper and lower engagement surfaces of the leading wedge <NUM> can combine so as to define a constant and continuously rounded convex engagement surface. Similarly, the trailing wedge <NUM> can define upper and lower engagement surfaces flare toward the leading wedge <NUM> as they extend away from the upper and lower plates <NUM> and <NUM>, respectively. In one example, the upper and lower engagement surfaces of the trailing wedge <NUM> can combine so as to define a constantly rounded convex engagement surface.

When the wedges <NUM> and <NUM> are drawn, pulled, or otherwise moved toward each other along the longitudinal direction L, the upper and lower engagement surfaces of the leading wedge <NUM> bear against the respective leading upper and lower sloped engagement surfaces <NUM> and <NUM>, respectively. Similarly, the upper and lower engagement surfaces of the trailing wedge <NUM> bear against the respective trailing upper and lower sloped engagement surfaces <NUM> and <NUM>, respectively. The result is that the housing <NUM> expands from the first or insertion configuration illustrated in <FIG> to the second or expanded configuration illustrated in <FIG>. In particular, the wedges <NUM> and <NUM> urge the upper and lower housing portions <NUM> and <NUM> to move away from each other along the transverse direction T. Accordingly, the upper and lower bearing surfaces <NUM> and <NUM> move away from each other along the transverse direction T. When the intervertebral cage <NUM> is in the first or initial configuration, the upper and lower bearing surfaces <NUM> and <NUM> are spaced apart from each other a first distance along the transverse direction T. when the intervertebral cage <NUM> is in the second or expanded configuration, the upper and lower bearing surfaces <NUM> and <NUM> are spaced apart from each other a second distance along the transverse direction T that is greater than the first distance. As the upper and lower bearing surfaces <NUM> and <NUM> move away from each other, the upper and lower sidewalls <NUM> and <NUM> slide along each other.

The upper and lower bearing surfaces <NUM> and <NUM> define a first relative angular orientation with respect to each other when the intervertebral cage <NUM> is in the first or initial configuration. The spring member <NUM> can bias the upper housing portion <NUM> toward the first relative angular orientation. In one example, the upper and lower bearing surfaces <NUM> and <NUM> can be oriented parallel to each other in the first relative angular orientation. The upper and lower bearing surfaces <NUM> and <NUM> define a second relative angular orientation with respect to each other when the intervertebral cage <NUM> is in the second or expanded configuration. In one example, the second relative angular orientation can be the same as the first relative angular orientation. Thus, the upper and lower bearing surfaces <NUM> and <NUM> can be oriented parallel to each other in the second relative angular orientation.

In some examples, the intervertebral cage <NUM> can allow for angular adjustment of the upper and lower plates <NUM> and <NUM> relative to one another against the force of the spring <NUM>. A drive assembly, including the driver component <NUM> and wedges <NUM> and <NUM>, can be configured to float at least partially or fully within a housing assembly. The housing assembly can include the housing <NUM>, including the upper and lower plates <NUM> and <NUM>, and the elastic member, such as the spring <NUM>, connected between the upper and lower plates <NUM> and <NUM>. The driver component <NUM> can include a drive end <NUM> that can be configured to engage an actuation tool that is configured to drive the driver component <NUM>. For instance, the actuation tool can be configured to rotate the driver component <NUM>. The drive end <NUM> can, for instance, define an opening <NUM> that is configured to receive the actuation tool. The driver component can further include a shaft <NUM> that supports the first and second wedges <NUM> and <NUM>.

The shaft <NUM> can be a threaded shaft <NUM> that has threads <NUM> at its distal end opposite the drive end <NUM>. Thus, the threads <NUM> can be disposed at the front end of the shaft <NUM>. The first wedge <NUM> can be configured to threadedly engage the shaft <NUM>. For instance, the first wedge can carry internal threads <NUM> that are configured to threadedly mate with the threads <NUM> of the shaft <NUM>. In one example, the first wedge <NUM> can receive a nut <NUM> that is not rotatable within the first wedge <NUM>. The nut <NUM> can define the internal threads <NUM>. Alternatively, the first wedge <NUM> can define the internal threads <NUM>. Thus, as the shaft <NUM>, and thus the driver component <NUM>, rotates in a first direction of rotation, the threaded engagement applies a force to the first wedge <NUM> toward the second wedge <NUM>, which decreases the longitudinal distance between the first and second wedges <NUM> and <NUM>. As the shaft <NUM>, and thus the driver component <NUM>, rotates in an opposite second direction of rotation, the threaded engagement applies a force to the first wedge <NUM> away from the second wedge <NUM>, which increases the longitudinal distance between the first and second wedges <NUM> and <NUM>.

The second wedge member <NUM> can be configured to translate freely along the shaft <NUM>. In particular, the second wedge member <NUM> can translate along the shaft <NUM> toward and away from the first wedge member <NUM> without actuating the shaft <NUM>. It is recognized, however, that a load applied to the plates <NUM> and <NUM> will cause the second ramp <NUM> to abut a stop member <NUM> of the driver component <NUM> that prevents the second wedge <NUM> from backing off of the shaft <NUM>. Alternatively, the first wedge <NUM> can be freely slidable along the shaft <NUM>. Thus, both of the wedges <NUM> and <NUM> can be freely slidable along the shaft <NUM>. Alternatively, one of the wedges <NUM> and <NUM> can be freely slidable along the shaft <NUM>, while the other of the wedges <NUM> and <NUM> can be threadedly engaged with the shaft <NUM>. During operation, as the shaft <NUM> is rotated in the first direction of rotation, the first wedge <NUM> is threadedly drawn toward the second wedge <NUM>. However, one or both of the first and second wedges <NUM> and <NUM> can move toward the other of the first and second wedges <NUM> and <NUM>, depending on the load applied to the cage <NUM>.

That is, the first wedge <NUM> can move toward the second wedge <NUM> along the longitudinal direction L while the second wedge <NUM> remains stationary with respect to movement along the longitudinal direction L. Alternatively, the second wedge <NUM> can move toward the first wedge <NUM> along the longitudinal direction L while the first wedge <NUM> remains stationary with respect to movement along the longitudinal direction L. Alternatively still, each of the first and second wedges <NUM> and <NUM> can move toward the other of the first and second wedges <NUM> and <NUM>. In some examples, one of the first and second wedges <NUM> and <NUM> can move a greater distance than the other of the first and second wedges <NUM> and <NUM>.

In particular, a compressive load applied to one end of the cage <NUM> will cause the plates <NUM> and <NUM> to apply a compressive force to the corresponding wedge. Thus, a compressive load applied to the leading end <NUM> of the cage <NUM> causes the leading ends of the plates <NUM> and <NUM> to apply a compressive load to the leading wedge <NUM>. As a result, actuation of the driver component <NUM> in the first direction can cause the trailing wedge <NUM> can move toward the leading wedge <NUM>, as the leading wedge <NUM> is maintained stationary due to frictional forces between the leading wedge <NUM> and the upper and lower plates <NUM> and <NUM> resulting from the compression of the plates <NUM> and <NUM> against the leading wedge. Accordingly, the cage <NUM> will angulate such that the trailing end <NUM> has a height greater than the leading end <NUM>.

Conversely, a compressive load applied to the trailing end <NUM> of the cage <NUM> causes the trailing ends of the plates <NUM> and <NUM> to apply a compressive load to the trailing wedge <NUM>. As a result, actuation of the driver component <NUM> in the first direction can cause the leading wedge <NUM> to move toward the trailing wedge <NUM>, as the trailing wedge <NUM> is maintained stationary due to frictional forces between the trailing wedge <NUM> and the upper and lower plates <NUM> and <NUM> resulting from the compression of the plates <NUM> and <NUM> against the trailing wedge <NUM>. Accordingly, the cage <NUM> will angulate such that the leading end <NUM> has a height greater than the trailing end <NUM> (see <FIG>).

Alternatively still, if the load applied to the cage <NUM> is uniform, the first and second wedges <NUM> and <NUM> can travel equal distances along the longitudinal direction L, and the relative orientation of the upper and lower plates <NUM> and <NUM> prior to expansion will equal the relative orientation of the upper and lower plates <NUM> and <NUM> after expansion.

Thus, it should be appreciated that the wedges <NUM> and <NUM> can adopt a relative position that is based on a load distribution on the plates <NUM> and <NUM>. The load distribution can be applied by the anatomical load once the intervertebral cage <NUM> has been implanted in the intervertebral space. Depending on the orientation of the load, expansion of the cage <NUM> along the transverse direction T will stop on one side and can be continued on the other side as the cage <NUM> is expanded until the plates <NUM> and <NUM> are in complete contact with the respective vertebral endplates. Thus, the intervertebral cage <NUM> may be angularly adjustable and expandable with an integrated expansion and angular adjustment mechanism that is entirely contained within the housing <NUM>. In this regard, the second relative angular orientation can be different than the first relative angular orientation. It is contemplated that normal anatomical loads will not cause the wedges <NUM> and <NUM> to move away from each other along the longitudinal direction L.

The driver component <NUM> may have a tool-engaging opening <NUM> to attach to a tool for actuation. The tool can be configured to drive the driver component <NUM> to draw the wedges <NUM> and <NUM> toward each other to expand the implant, and can further be configured to cause the wedges <NUM> and <NUM> to separate from each other. It is contemplated that any type of driving mechanism may be employed for the driver component <NUM>. For example, one may be a threaded screw or bolt mechanism, while in another example the driving mechanism may be a push-pull mechanism. In another example, the driving mechanism may employ a pulley type mechanism, and in still another example, the driving mechanism may employ a tie wrap or elastically deformable capture mechanism.

<FIG> illustrate another example of an expandable and angularly adjustable intervertebral cage <NUM> of the present disclosure. Like the intervertebral cage <NUM> described above with respect to <FIG>, this intervertebral cage <NUM> can include a housing <NUM> that, in turn, includes an upper housing portion <NUM> and a lower housing portion <NUM>. The upper housing portion <NUM> includes an upper plate <NUM> that defines an upper bearing surface <NUM>. The lower housing portion <NUM> includes a lower plate <NUM> that defines a lower bearing surface <NUM>. The upper and lower plates <NUM> and <NUM>, respectively, are configured for placement against endplates of a pair of adjacent vertebral bodies in an intervertebral space that is defined between the vertebral bodies. In one example, the bearing surfaces <NUM> and <NUM> can be flat for placement against the endplates. It is understood, of course, that the bearing surfaces <NUM> and <NUM> may also be sloped as desired. For instance, the bearing surfaces <NUM> and <NUM> can be convex and rounded if desired. Further, the upper and lower bearing surfaces <NUM> and <NUM> can be defined by flexible slates that are spaced from each other along the lateral direction A, and elongate along the longitudinal direction L.

The upper housing portion <NUM> can include upper sidewalls <NUM> that extend down from the upper plate <NUM>, and the lower housing portion <NUM> can include lower sidewalls <NUM> that extend up from the lower plate <NUM>. The sidewalls <NUM> and <NUM> are configured to slide along each other, and can allow the upper and lower housing portions <NUM> and <NUM>, and thus the upper and lower plates <NUM> and <NUM>, to translate and rotate in relation to each other vertically, as explained below. Further, as shown in <FIG>, the upper housing portion <NUM> can include a plurality of pairs of protrusions 228a-228c that extend out from the upper sidewalls <NUM> proximate to a lowermost end of the upper sidewalls <NUM>. The protrusions 228a-228c can be configured as rounded knobs or protrusions, or any alternative geometry as desired. The first protrusions 228a can be positioned as first outer projections, the second protrusions 228b can be positioned as second outer projections, and the third protrusions 228c can be configured as middle outer projections that are disposed between the first and third outer projections along the longitudinal direction L.

One of the upper and lower housing portions <NUM> and <NUM> can include at least one seat <NUM>, and the other of the upper and lower housing portions <NUM> and <NUM> can include a spring member <NUM> having a free end that bears against the seat. In one example, the lower housing portion <NUM> can include the spring member <NUM> that extends along one or both of the lower sidewalls <NUM>. The upper plate <NUM> can include the at least one seat that extends out from the upper sidewall <NUM>. The at least one seat can be in in the form of semi-circular or rounded pins <NUM>, or any suitable alternative geometry, that extends out from the upper sidewalls proximate to an upper end of the upper sidewalls <NUM>. The combination of the elastically deformable spring <NUM> and the pins <NUM> form an elastic interconnection between the upper and lower housing portions <NUM> and <NUM>, and thus also between the upper and lower plates <NUM> and <NUM>, as shown in <FIG>.

The intervertebral cage <NUM> can further include an integrated expansion and angular adjustment mechanism that is fully integrated within the intervertebral cage <NUM>. The angular adjustment mechanism can be disposed between the upper and lower plates <NUM> and <NUM>, respectively. For instance, the angular adjustment mechanism can be disposed between the upper plate <NUM> and the lower plate <NUM> with respect to the transverse direction T. The angular adjustment mechanism can include at least one wedge. For instance, the angular adjustment mechanism can include first and second wedges <NUM> and <NUM>, respectively. The first and second wedges <NUM> and <NUM> can be disposed opposite each other with respect to the longitudinal direction L. It should thus be appreciated that the intervertebral cage <NUM> can consist of four (<NUM>) separate components that can be manufactured or SLM printed in one run. The four separate components can be defined by the upper hosing portion <NUM>, the lower housing portion <NUM>, the first wedge <NUM>, and the second wedge <NUM>.

The first wedge <NUM> can be aligned with a first portion of the upper plate <NUM> along the transverse direction T. Similarly, the second wedge <NUM> can be aligned with a second portion of the upper plate <NUM> along the transverse direction T. Because the wedges <NUM> and <NUM> are movable along the longitudinal direction L, the location of the first and second portions of the upper plate <NUM> can likewise vary as the wedges <NUM> and <NUM> move.

The wedges <NUM> and <NUM> can have engagement surfaces that can be angled, rounded, or otherwise angularly offset with respect to the transverse direction T as they extend in the longitudinal direction L. For instance, the engagement surfaces can be straight linear surfaces. In one example, each wedge <NUM> and <NUM> can include a pair of laterally opposed sloped slots <NUM> that define the engagement surfaces. The sloped slots <NUM> of the first wedge <NUM> can be sloped toward the second wedge <NUM> as they extend away from the upper plate <NUM> along the transverse direction T. Similarly, the sloped slots <NUM> of the second wedge <NUM> can be sloped toward the first wedge <NUM> as they extend away from the upper plate <NUM> along the transverse direction T. As will be appreciated from the description below, the sloped slots <NUM> of the first and second wedges <NUM> and <NUM> are configured to receive the protrusions 228a and 228b, respectively, so as to cause at least a portion of the first plate <NUM> to move away from the second plate <NUM> along the transverse direction T, thereby expanding and/or angulating the cage <NUM>. The lower plate <NUM> can remain stationary during movement of the upper plate <NUM>.

The lower plate <NUM> may include at its far longitudinal ends a pair of stop members <NUM> that can prevent the wedges <NUM> and <NUM> from backing out of the housing <NUM>. The lower housing portion <NUM> can further include at least one guide rail <NUM> that is configured to be received by a corresponding channel <NUM> that extends through the wedges <NUM> and <NUM> along the longitudinal direction L. The at least one guide rail <NUM> can be oriented along the longitudinal direction L. Further, the at least one guide rail <NUM> can extend along a transverse inner surface of the lower plate <NUM>. In one example, the lower housing portion <NUM> can include first and second guide rails <NUM> that are spaced from each other along the lateral direction A and are received in respective channels <NUM> of the wedges <NUM> and <NUM>. The guide rails <NUM> can have outwardly projecting teeth <NUM> (see <FIG>). Similarly, the wedges <NUM> can include at least one complementary finger <NUM> in the channels <NUM> that is configured to engage and interlock with the teeth <NUM> of the guide rails <NUM> (see <FIG>).

During operation, the wedges <NUM> can be deployed individually and are configured to slide individually along the guide rails <NUM> along the longitudinal direction L. The sloped slots <NUM> of the first wedge member <NUM> receive the first protrusions 228a, and the sloped slots <NUM> of the second wedge member <NUM> receive the third protrusions 228b. Thus, as shown in <FIG>, as each of the members <NUM> and <NUM> translates longitudinally toward the other wedge member <NUM> and <NUM>, the engagement surfaces of the wedge members <NUM> defined by the sloped slots <NUM> bear against the first and second protrusions 228a and 228b, respectively, which urges the upper housing portion <NUM>, and thus the upper plate <NUM>, to move away from the lower housing portion <NUM>, and thus the lower plate <NUM>, along the transverse direction T.

The lower housing portion <NUM> can define a transverse slot <NUM> that extends into each of the lower sidewalls <NUM> (see <FIG>). The transverse slots <NUM> are configured to receive the third protrusion 228c. Alternatively, the upper housing portion <NUM> can define the transverse slot <NUM> that extends into each of the upper sidewalls, and the third protrusion 228c can be carried by the lower housing portion <NUM>. The third protrusions 228c can ride along the transverse slots <NUM> as the upper housing portion <NUM> moves relative to the lower housing portion <NUM> along the transverse direction. It should be appreciated that the middle protrusion 228c travels along the vertical or transverse direction T in the transverse slot <NUM>, while the first and second protrusions 228a and 228b ride in the sloped slots <NUM> that are angled with respect to the transverse direction T. As illustrated in <FIG> and <FIG>, the first relative angular orientation of the plates <NUM> and <NUM> prior to expansion can equal the second relative angular orientation of the plates <NUM> and <NUM> after expansion.

Referring now to <FIG>, the wedges <NUM> and <NUM> can be separately deployable and independently movable. Independently moving one of the wedges <NUM> and <NUM> can cause angular adjustment of the intervertebral cage <NUM>. In particular, independently moving the wedges <NUM> and <NUM> can cause angular adjustment of the upper plate <NUM> with respect to the lower plate <NUM>. For instance, by moving the first wedge <NUM> toward the second wedge <NUM> while maintaining the second wedge <NUM> stationary, the upper plate <NUM> may be angularly adjusted. In particular, the first portion of the upper plate <NUM> can move away from the lower plate <NUM> along the transvers direction T relative to the second portion of the upper plate <NUM>. It should be appreciated that the upper plate <NUM> can angulate both when the second wedge <NUM> remains stationary, or when the first wedge <NUM> translates along the longitudinal direction at a disproportionate amount with respect to the translation of the second wedge <NUM> (both referred to as movement of the first wedge relative to the second wedge along the longitudinal direction L). Translation of both wedges <NUM> and <NUM> a disproportionate amount can cause the cage <NUM> to both expand along the transverse direction T and angulate. It should be further appreciated that the upper plate <NUM> can angularly adjust about the middle protrusion 228c as it is disposed in the transverse slot <NUM>. Thus, the middle protrusion <NUM> can define a fulcrum for angular movement of the upper plate <NUM>. Accordingly, the second relative angular orientation of the first and second plates <NUM> can be different than the second relative angular orientation of the first and second plates <NUM>. It should be appreciated that an opposite angular adjustment can also be achieved by moving the second wedge <NUM> relative to the first wedge along the longitudinal direction L.

If it is desired to achieve the second relative angular orientation equal to the first relative angular orientation, the second wedge <NUM> can be moved longitudinally toward the first wedge <NUM>, which urges the second location of the upper plate <NUM> to move relative to the first location of the upper plate <NUM> away from the lower plate <NUM> along the transverse direction. This causes the upper plate <NUM> to angulate about the middle protrusion 228c until the first and second portions of the upper plate <NUM> are equally spaced from the lower plate <NUM> along the transverse direction T. The resultant intervertebral cage <NUM> can have parallel upper and lower plates <NUM> and <NUM> in its second or expanded configuration. The first and second wedges <NUM> and <NUM> can be moved away from each other so as to urge the upper plate <NUM> to move toward the lower plate <NUM> along the transverse direction T, if it is desired to collapse the intervertebral cage <NUM>. The sidewalls <NUM> and <NUM> can slide along each other as the cage <NUM> expands and angulates.

Referring now to <FIG> and <FIG>, and as described above, the housing <NUM> can define the guide rails <NUM>, and the first and second wedges <NUM> and <NUM> can define the channels <NUM> that receive and ride along the guide rails <NUM> as the first and second wedges <NUM> and <NUM> translate longitudinally. The finger <NUM> can be a click finger <NUM> that is configured to ride along the teeth <NUM> as the wedges <NUM> and <NUM> move toward one another along the longitudinal direction L. However, the finger <NUM> can interlock with the teeth <NUM> so as to prevent movement of the first and second wedge members <NUM> and <NUM> away from each other in response to anatomical loading. Alternatively, the finger <NUM> can interlock with the teeth <NUM> so as to prevent movement of the first and second wedge members <NUM> and <NUM> both toward and away from each other. An implant assembly can include a bayonet type actuation instrument <NUM> that is insertable be inserted into a tool-engaging opening <NUM> of either wedge <NUM>. The instrument <NUM> can be configured to urge the fingers <NUM> away from the teeth <NUM>, thereby disengaging the fingers <NUM> from the teeth <NUM>. Thus, engagement between the fingers <NUM> and the teeth <NUM> no longer prevents relative movement of the wedges <NUM> and <NUM> away from each other and, in some examples, toward each other. In one example, turning a bayonet-shaped end of the tool (for instance <NUM> degrees) can cause the fingers <NUM> to be urged away from the teeth <NUM>, thereby unlocking the wedge <NUM> from the teeth <NUM>. Releasing the instrument <NUM> can cause the fingers <NUM> to again engage the teeth <NUM>, thereby locking the wedge <NUM> in place relative to the rails <NUM>.

It is appreciated that the spring member <NUM> can provide a pre-tension that connect the upper housing portion <NUM> and the lower housing portion <NUM> together. The spring member <NUM> can be shaped to allow both vertical and angular movement of the type described above against the pre-tensioned spring force. The spring members <NUM> can be designed to only allow the movements described above.

<FIG> illustrate yet another example of an expandable and angularly adjustable intervertebral cage <NUM> of the present disclosure. The intervertebral cage <NUM> can include an outer housing <NUM> and upper and lower housing portions <NUM> and <NUM> that are movable within the outer housing <NUM>. The outer housing <NUM> can have an open top and bottom to accommodate movement of the upper and lower housing portions <NUM> and <NUM>. The upper housing portion <NUM> can include an upper plate <NUM> and upper sidewalls <NUM> that extend down from the upper plate <NUM> along the transverse direction T. The lower housing portion <NUM> can include a lower plate <NUM> and lower sidewalls <NUM> that extend up from lower plate <NUM> along the transverse direction T. The upper and lower plates <NUM> and <NUM>, respectively, can be configured to be placed against endplates of a pair of adjacent vertebral bodies. The upper plate <NUM> can define an upper bearing surface configured to abut a vertebral endplate of a superior vertebral body, and the lower plate <NUM> can define a lower bearing surface configured to abut a vertebral endplate of an inferior vertebral body. In one example, the bearing surfaces can be substantially flat. It is understood, of course, that the bearing surfaces can be shaped surfaces, such as convex, and rounded, if desired.

<FIG> shows the intervertebral cage <NUM> in an expanded configuration whereby a distance between the upper and lower plates <NUM> and <NUM> has increased along the transverse direction T. <FIG> shows the same intervertebral cage <NUM> in an expanded, and angularly adjusted, configuration, whereby a relative angular orientation between the upper and lower plates <NUM> and <NUM> have been changed.

With reference to <FIG>, the intervertebral cage <NUM> further includes an expansion and angular adjustment mechanism disposed between the upper and lower plates <NUM> and <NUM> with respect to the transverse direction T. The expansion and angular adjustment mechanism can include first and second brackets <NUM> and <NUM> that are disposed in the outer housing <NUM>. The first and second brackets <NUM> and <NUM> can be configured as brackets in one example. The first bracket <NUM> can be aligned with both a first portion of the upper plate <NUM> and a first portion of the lower plate <NUM> along the transverse direction T. Similarly, the second bracket <NUM> can be aligned with a second portion of the upper plate <NUM> and a second portion of the lower plate <NUM> along the transverse direction T. Because the brackets <NUM> and <NUM> are movable along the longitudinal direction L as described below, the location of the first and second portions of the upper and lower plates <NUM> and <NUM> can likewise vary as the brackets <NUM> and <NUM> move.

Each of the first and second brackets <NUM> and <NUM> can have engagement surfaces that can be angled, rounded, or otherwise angularly offset with respect to the transverse direction T as they extend in the longitudinal direction L. For instance, the engagement surfaces can be straight linear surfaces. In one example, each bracket <NUM> and <NUM> can include a pair of laterally opposed sloped upper slots <NUM> and laterally opposed lower slots <NUM> that define the engagement surfaces. The upper sloped slots <NUM> of the first bracket <NUM> can be sloped away from the second bracket <NUM> as it extends away from the upper plate <NUM> along the transverse direction T. The upper sloped slots <NUM> of the second bracket <NUM> can be sloped away from the first bracket <NUM> as it extends away from the upper plate <NUM> along the transverse direction T. The lower sloped slots <NUM> of the first bracket <NUM> can be sloped away from the second bracket <NUM> as it extends away from the lower plate <NUM> along the transverse direction T. The lower sloped slots <NUM> of the second bracket <NUM> can be sloped away from the first bracket <NUM> as it extends away from the lower plate <NUM> along the transverse direction T. As will now be described, the sloped slots <NUM> and <NUM> are configured to receive projections of the upper and lower plate members <NUM> and <NUM> that urge the upper and lower plates <NUM> and <NUM> to move relative to each other along the transverse direction T, thereby expanding and/or angulating the cage <NUM>.

In particular, the upper plate portion <NUM> can include first and second pairs of upper protrusions <NUM>. The upper protrusions <NUM> can extend out from the upper sidewalls <NUM>. Each of the pairs can be spaced from each other along the longitudinal direction L. Further, the upper protrusions <NUM> of each pair can be opposite each other along the lateral direction A. The upper protrusions <NUM> can be configured as knobs in one example. The protrusions <NUM> are sized to be received in the upper sloped slots <NUM>, and freely slidable in the upper sloped slots <NUM>. The first pair of upper protrusions <NUM> are configured to ride in the upper slots of the first bracket <NUM>. The second pair of upper protrusions <NUM> are configured to ride in the upper slots of the second bracket <NUM>.

Similarly, the lower plate portion <NUM> can include first and second pairs of lower protrusions <NUM>. The lower protrusions <NUM> can extend out from the lower sidewalls <NUM>. Each of the pairs can be spaced from each other along the longitudinal direction L. Further, the lower protrusions <NUM> of each pair can be opposite each other along the lateral direction A. The lower protrusions <NUM> can be configured as knobs in one example. The lower protrusions <NUM> are sized to be received in the lower sloped slots <NUM>, and freely slidable in the lower sloped slots <NUM>. For instance, the first pair of lower protrusions <NUM> are configured to be received in the lower sloped slots <NUM> of the first bracket <NUM>. The second pair of lower protrusions <NUM> are configured to be received in the lower sloped slots <NUM> of the second bracket <NUM>. Thus, the upper and lower protrusions <NUM> and <NUM> can define engagement surfaces that ride along respective engagement surfaces in the upper and lower slots <NUM> and <NUM> so as to cause the upper and lower housing portions <NUM> and <NUM> to move relative to each other along the transverse direction T.

The outer housing <NUM> can define a pair of transverse side channels <NUM> that are aligned in the lateral direction A with one of the protrusions <NUM> and <NUM> that extend through one of the brackets <NUM> and <NUM>, illustrated as the first bracket <NUM>. Thus, the upper and lower protrusions <NUM> and <NUM> that extend though the respective upper and lower slots <NUM> and <NUM> of the first bracket <NUM> can further extend into the channels <NUM>. Because the side channels <NUM> are elongate along the transverse direction T, the engagement of the side channels <NUM> with the respective protrusions <NUM> and <NUM> prevents or limits longitudinal movement of the upper and lower plates <NUM> and <NUM>. In one example, the outer housing <NUM> does not define any side channels <NUM> that receive the protrusions of the second bracket <NUM>.

The intervertebral cage <NUM>, and in particular the expansion and angular adjustment mechanism, can include a first actuation rod <NUM> that is translatably fixed to the first bracket <NUM> and longitudinally translatable with respect to the second bracket <NUM>, and a second actuation rod <NUM> that is translatably fixed to the second bracket <NUM> and longitudinally translatable with respect to the first bracket <NUM>. The first and second rods <NUM> and <NUM> can extend gripping ends that extend longitudinally out from the outer housing <NUM>. Thus, the first bracket <NUM> moves longitudinally with the first actuation rod <NUM>. Similarly, the second bracket <NUM> moves longitudinally with the second actuation rod <NUM>. In one example, the first and second actuation rods <NUM> and <NUM> can be configured as pull rods that are configured to be pulled longitudinally to effect sliding longitudinal movement of the brackets <NUM> and <NUM>.

As described above, first ones of the upper and lower protrusions <NUM> and <NUM> of the upper housing member <NUM> and lower housing member <NUM> are slidable in the upper and lower sloped slots <NUM> and <NUM>, respectively, of the first bracket <NUM>. This causes the distance between the first portions of the first and second plates <NUM> and <NUM> to change along the transverse direction. For instance, as the first bracket <NUM> is moved away from the second bracket <NUM>, the first protrusions <NUM> and <NUM> push against the upper and lower housing portions <NUM> and <NUM>. Thus, the distance between the first portions of the first and second plates <NUM> and <NUM> increases along the transverse direction T. As the first bracket <NUM> is moved toward the second bracket <NUM>, the distance between the first portions of the first and second plates <NUM> and <NUM> decreases along the transverse direction T.

Similarly, second ones of upper and lower protrusions <NUM> and <NUM> of the upper housing member <NUM> and lower housing member <NUM> are slidable in the upper and lower sloped slots <NUM> and <NUM>, respectively, of the second bracket <NUM>. This causes the distance between the second portions of the first and second plates <NUM> and <NUM> to change along the transverse direction T. For instance, as the second bracket <NUM> is moved away from the first bracket <NUM>, the second protrusions <NUM> and <NUM> push against the upper and lower housing portions <NUM> and <NUM>. Thus, the distance between the second portions of the first and second plates <NUM> and <NUM> increases along the transverse direction T. As the second bracket <NUM> is moved toward the first bracket <NUM>, the distance between the second portions of the first and second plates <NUM> and <NUM> decreases along the transverse direction T.

The first and second actuation rods <NUM> and <NUM> are configured to move longitudinally relative to the outer housing <NUM>. Longitudinal movement of the rods <NUM> and <NUM> causes the respective brackets <NUM> and <NUM> affixed to the rod to be likewise moved longitudinally. In each of the brackets <NUM> are upper and lower angled slots <NUM> and <NUM>, as described above. The slots <NUM> and <NUM> are integrated above and below each other, and angled in opposite directions. The slots <NUM> and <NUM> of the first bracket <NUM> are mirrored and can be deployed independently of the slots <NUM> and <NUM> of the second wedge member <NUM>, and vice versa. The mechanism within the outer housing <NUM> enables the upper and lower plates <NUM>, <NUM> to slide vertically at the hinge or pivot joints defined by the knobs <NUM>, <NUM> within the angled slots <NUM>. Further, the first protrusions <NUM> and <NUM> can slide within the transverse side channel <NUM> of the outer housing <NUM>, while the second protrusions <NUM> and <NUM> can slide only within the respective slots of the second bracket <NUM>.

A method of actuating the intervertebral cage <NUM> will now be described with reference to <FIG>. In a starting position illustrated in <FIG>, with the intervertebral cage <NUM> in its first or insertion configuration, the upper and lower projections <NUM> and <NUM> are in the transverse innermost position of the respective slots <NUM> and <NUM>, respectively. Further, the first projections <NUM> and <NUM> are in their respective transverse innermost positions in the side channels <NUM>. Referring to <FIG>, when the second rod <NUM> is actuated to move the second bracket <NUM> longitudinally away from the first bracket <NUM>, the second upper and lower protrusions <NUM> and <NUM> are forced upward and downward, respectively, by the angled slots <NUM> and <NUM> of the second bracket <NUM>. Thus, the second portions of the upper and lower plates <NUM> and <NUM> are moved away from each other along the transverse direction T. The first portions of the upper and lower plates <NUM> and <NUM> can remain stationary with respect to relative movement along the transverse direction T, thereby effecting expansion and angular adjustment of the intervertebral cage <NUM> as shown in <FIG>. In particular, respective angular orientations of the upper and lower plates <NUM> and <NUM> can change with respect to the outer housing <NUM>. Thus, it will be further appreciated that the second relative angular orientation of the cage <NUM> can be different than the first angular orientation of the cage <NUM>.

Referring now to <FIG>, when the first rod <NUM> is actuated to move the first bracket <NUM> longitudinally away from the second bracket <NUM>, the first upper and lower protrusions <NUM> and <NUM> are forced upward and downward, respectively, by the angled slots <NUM> and <NUM> of the first bracket <NUM>. Thus, the first portions of the upper and lower plates <NUM> and <NUM> are moved away from each other along the transverse direction T. The second portions of the upper and lower plates <NUM> and <NUM> can remain stationary with respect to relative movement along the transverse direction T. The first portions of the upper and lower plates <NUM> and <NUM> can expand vertically to a position whereby that the first and second plates <NUM> and <NUM> are in the same relative angular orientation as before expansion. Thus, the first relative angular orientation can be equal to the second relative angular orientation. Alternatively, the first portions of the upper and lower plates <NUM> and <NUM> can expand vertically to a position whereby that the first and second plates <NUM> and <NUM> are in a different relative angular orientation as before expansion.

Movement of the rods <NUM> and <NUM> can be restricted by the outer housing <NUM> to movement along the longitudinal direction L. Because the engagement between the first upper and lower protrusions <NUM> and <NUM> in the vertical channel <NUM>, the upper and lower housing portions <NUM> and <NUM> are prevented from moving longitudinally. Further, the first upper protrusion <NUM> can define a fulcrum about which the second portion of the upper plate <NUM> can angulate when the second bracket <NUM> is moved away from the first bracket <NUM>.

<FIG> illustrate even still more examples of expandable and angularly adjustable intervertebral cages <NUM>, <NUM>' of the present disclosure. <FIG> show an intervertebral cage <NUM> configured for anterior lumbar interbody fusion (ALIF), while <FIG> show the same intervertebral cage <NUM>' but configured for lateral lumbar interbody fusion (LLIF). The intervertebral cage <NUM> of <FIG> shown includes features of the intervertebral cage <NUM> described above, such as the internal mechanism for expansion and angular adjustment. As shown, the cage <NUM> can include a first or leading end <NUM> and a second or trailing end <NUM> opposite the leading end <NUM> along the longitudinal direction L. The cage <NUM> can include a housing <NUM> that includes an upper housing portion <NUM> and a lower housing portion <NUM>. The upper housing portion <NUM> can include an upper plate <NUM> and upper sidewalls <NUM> that extend down from the upper plate <NUM> along the transverse direction T. The lower housing portion <NUM> can include a lower plate <NUM> and lower sidewalls <NUM> that extend up from the lower plate <NUM> along the transverse direction T. The intervertebral cage <NUM> can further include a pair of wedges <NUM> and <NUM> that translate on a guide rail <NUM> located on an inner transverse surface of the lower plate <NUM>, and can move in a manner as described above for intervertebral cage <NUM>. However, the intervertebral cage <NUM> can further include porous structures <NUM> on one or both of the upper plate <NUM> and the lower plate <NUM> that facilitate cellular activity and bony ingrowth. Thus, the porous structures <NUM> can define at least a portion of the upper and lower bearing surfaces of the upper and lower plates <NUM> and <NUM>, respectively.

Referring to <FIG>, the longitudinal or horizontal movement of the wedges <NUM> and <NUM> (independently of one another) effects the expansion in height and the angular adjustment of the plates <NUM> and <NUM> relative to one another, as represented by the drawing in <FIG> and as described above with respect to the intervertebral cage <NUM>. <FIG> shows the intervertebral cage <NUM> in a first or unexpanded insertion configuration and attached to an insertion and actuation instrument <NUM>. <FIG> shows the first wedge <NUM> longitudinally moved towards the second wedge <NUM> using the attached instrument <NUM>, causing the cage <NUM> to expand and also be angularly adjusted. <FIG> shows the second wedge <NUM> longitudinally moved towards the first wedge <NUM> using the attached instrument <NUM>, causing the cage <NUM> to expand and also be oppositely angularly adjusted. Thus, it should be appreciated that the independent movement of the wedges <NUM> and <NUM> allows the user to adjust the angle of the cage <NUM> between a first angle whereby the upper plate <NUM> is sloped toward the lower plate in a first longitudinal direction and a second angle whereby the upper plate <NUM> is sloped toward the lower plate <NUM> in a second longitudinal direction that is opposite the first longitudinal direction, as shown schematically in <FIG>.

In general, the intervertebral cage <NUM> of the present disclosure may be configured for anterior lumbar interbody fusion (ALIF). The cage <NUM> can be dimensioned as desired. In one example, the cage <NUM> may have dimensions ranging from 34x25; 37x27; 40x29; and 45x32 mm. Thus, the longitudinal length of the cage <NUM> can range from approximately <NUM> and approximately <NUM> (with approximately <NUM> increments therebetween). The lateral width of the cage <NUM> can range from approximately <NUM> to approximately <NUM> (with approximately <NUM> increments therebetween). The height of the cage <NUM> along the transverse direction from the upper bearing surface to the lower bearing surface can range from approximately <NUM> to approximately <NUM> (with approximately <NUM> increments therebetween). The term "approximate" recognizes manufacturing tolerances and other potential variations, and includes plus or minus <NUM>% of the stated number. The angular adjustment may range from and to approximately <NUM> degrees, approximately <NUM> degrees, approximately <NUM> degrees, approximately <NUM> degrees, and approximately <NUM> degrees. It is contemplated that the cage <NUM> may allow a small step adjustment, and be reversible during the procedure. The cage <NUM> may be printed in one run, with deployment of the wedges <NUM> being independent and with the use of the dedicated actuator / insertion instrument <NUM>.

<FIG> illustrate an intervertebral cage <NUM>' that is similar to the intervertebral cage <NUM> previously described above, but configured for lateral lumbar interbody fusion (LLIF). While the cage <NUM> can be configured to angulate in the sagittal plane once implanted into the intervertebral disc space, the cage <NUM>' can be configured to angulate in the coronal plane when implanted into the intervertebral disc space. The cage <NUM>' is otherwise the same as cage <NUM>, and therefore share similar features as represented by the same reference number followed by the symbol " '". As shown, the cage <NUM>' may include a housing <NUM>' that, in turn, includes an upper housing portion <NUM>' and a lower housing portion <NUM>'. The upper housing portion <NUM>' includes an upper plate <NUM>' and upper sidewalls <NUM>' that extend down from the upper plate <NUM>' along the transverse direction T. The lower hosing portion <NUM>' includes a lower plate <NUM>' and lower sidewalls <NUM>' that extend up from the lower plate <NUM>' along the transverse direction T. The intervertebral cage <NUM>' can include a pair of wedges <NUM>' and <NUM>' that translate on a guide rail <NUM>' located on the inner transverse surface of the lower plate <NUM>', and move in a manner similar to what was described above for intervertebral cages <NUM> and <NUM>. The upper housing portion <NUM>' can also have porous structures <NUM>' on the upper plate <NUM>' may also have porous structures <NUM>' that facilitate cellular activity and bony ingrowth. Thus, at least a portion of the upper bearing surface of the upper plate <NUM>' can be defined by the porous structures <NUM>'.

As shown in <FIG>, the lateral or horizontal movement of the wedges <NUM>' (independently of one another) effects the expansion in height and the angular adjustment of the plates <NUM>', <NUM>' relative to one another. <FIG> and <FIG> show the intervertebral cage <NUM>' in a first or unexpanded insertion configuration and attached to an insertion / actuation instrument <NUM>. The wedges <NUM>' and <NUM>' of the intervertebral cage <NUM> can be longitudinally moved towards one another independently in <FIG> and <FIG> using the attached instrument <NUM>, causing the cage <NUM>' to expand and also be angularly adjusted in the manner described above. The independent movement of the wedges <NUM>' and <NUM>' allows the user to adjust the angle of the cage <NUM>', as shown in <FIG> and <FIG>.

In general, the intervertebral cage <NUM>' of the present disclosure may be configured for lateral lumbar interbody fusion (LLIF), and in one example, may have a longitudinal dimension ranging from approximately <NUM> to approximately <NUM>, including approximately <NUM>, approximately <NUM>, approximately <NUM>, approximately <NUM>, and approximately <NUM>. The cage <NUM> can have a lateral dimension that ranges from approximately <NUM> to approximately <NUM>, including approximately <NUM> and approximately <NUM>. The age can have a height that ranges from approximately <NUM> to approximately <NUM> (with approximately <NUM> increments therebetween). The angular adjustment of the cage <NUM>' may range from approximately <NUM> degrees to approximately <NUM> degrees, including approximately <NUM> approximately, approximately <NUM> degrees, and approximately <NUM> degrees, as measured by an angle defined by the upper and lower plates <NUM>' and <NUM>'. It is contemplated that the cage <NUM>' may allow a small step adjustment, and be reversible during the procedure. The cage <NUM>' may be printed in one run, with deployment of the wedges <NUM>' being independent and with the use of the dedicated actuator / insertion instrument <NUM>.

<FIG> illustrate even further still another example of an expandable and angularly adjustable intervertebral cage <NUM> of the present disclosure which utilizes many of the same features of the examples described above. As shown, the cage <NUM> can include a housing <NUM> that includes an upper housing portion <NUM> and a lower housing portion <NUM>. The upper housing portion <NUM> can include an upper plate <NUM> and upper sidewalls <NUM> that extend down from the upper plate <NUM>. The lower housing portion <NUM> can include a lower plate <NUM> and lower sidewalls <NUM> that extend up from the lower plate <NUM>. The intervertebral cage <NUM> can further include a pair of first and second wedges <NUM> and <NUM> that translate independently of each other on a guide rail <NUM> located on an inner transverse surface of the lower plate <NUM>. The wedges <NUM> and <NUM> can move in the manner described above with respect to the intervertebral cage <NUM> so as to expand and angularly adjust the intervertebral cage <NUM> in the manner described above with respect to the cage <NUM>. In addition, the upper and lower plates <NUM> and <NUM> may be connected with elastic springs <NUM> to control the relative movement of the plates <NUM> and <NUM> in the manner described above. The springs <NUM> can be configured geometrically as elastically deformable strips <NUM>, or can be alternatively configured as desired.

As shown in <FIG>, when the intervertebral cage <NUM> is in its compressed, insertion configuration, the wedges <NUM> and <NUM> are in their initial configuration. As shown in <FIG> movement of the first wedge <NUM> toward the second wedge <NUM> along the guide rail <NUM> causes the upper plate <NUM> to move away from the lower plate <NUM> along the transverse direction (expansion), and further causes the first portion of the upper plate <NUM> to move relative to the second portion of the upper plate <NUM> away from the lower plate <NUM> along the transverse direction, thereby angularly adjusting the intervertebral cage <NUM>. As shown in <FIG>, movement of the second wedge <NUM> toward the first wedge <NUM> along the guide rail <NUM> causes the upper plate <NUM> to move away from the lower plate <NUM> along the transverse direction T (expansion), and further causes the second portion of the upper plate <NUM> to move relative to the first portion of the upper plate <NUM> away from the lower plate <NUM> along the transverse direction, thereby angularly adjusting the intervertebral cage <NUM>. Subsequent movement of the other of the first and second wedges <NUM> and <NUM> can return the cage <NUM> to its first relative angular orientation.

The elastic springs <NUM> can apply a force against the plates <NUM> and <NUM> that resists but allows movement of the upper plate <NUM> relative to the lower plate <NUM>. The springs <NUM> can be configured such that free ends of the spring <NUM> connect the upper plate <NUM> to the lower plate <NUM>, with no free ends of the spring <NUM> that are loose and unattached. For instance, one end of the spring <NUM> can attach to the lower plate <NUM>, and the other end of the spring <NUM> can attach to the upper plate <NUM>. The intervertebral cage <NUM> may be particularly advantageous when 3D printed in one run in a metal such as a titanium.

<FIG> illustrate yet still another example of an expandable and angularly adjustable intervertebral cage <NUM> of the present disclosure which utilizes many of the same features of the example described above. As shown, the cage <NUM> can include a housing <NUM> that, in turn, includes an upper housing portion <NUM> and a lower housing portion <NUM>. The upper housing portion <NUM> can include an upper plate <NUM> and upper sidewalls <NUM> that extend down from the upper plate <NUM> along the transverse direction T. The lower housing portion <NUM> can include a lower plate <NUM> and lower sidewalls <NUM> that extend up from the lower plate <NUM> along the transverse direction T. The intervertebral cage <NUM> can further include a pair of wedges <NUM> and <NUM> that translate on a guide rail <NUM> located on an inner transverse surface of the lower plate <NUM>, and can move in a manner as described above for intervertebral cage <NUM>. However, as an alternative or in addition to including spring members configured as elastically deformable strips, the cage <NUM> can include an alternative spring member <NUM> that resists but allows movement of the cage <NUM>. For instance, in one example, the cage <NUM> an include the spring <NUM> configured as a resilient lattice structure <NUM>. The lattice structure <NUM> can be configured as a honeycomb-like screen <NUM>. The spring member <NUM> can further define sides of the intervertebral cage <NUM> that extend from the upper plate <NUM> to the lower plate <NUM> and are spaced from each other along the lateral direction A.

The housing <NUM> can include a pair of wedges <NUM> and <NUM> that translate on a guide rail <NUM> located on a transverse inner surface of the lower plate <NUM>, and move in a manner as described above with respect to the intervertebral cage <NUM>. One or both of the upper plate <NUM> and the lower plate <NUM> can include a porous structure as described above with respect to cage <NUM>. For instance, the upper plate <NUM> can include a porous structure <NUM> that at least partially define the upper bearing surface. Further, the lower housing portion <NUM> can include a porous structure <NUM> that defines the lower bearing, as shown in <FIG> and <FIG>. Further, one or both of the upper and lower plates <NUM> and <NUM> can include teeth <NUM> configured to grip the respective vertebral endplate. One or both of the wedges <NUM> and <NUM> can define an instrument-engagement member that is configured to couple to an actuator that, in turn, is configured to move one or both of the wedges <NUM> and <NUM> to expand and/or angulate the intervertebral cage <NUM>. In one example, the instrument-engagement member can be configured as an instrument-engaging opening <NUM> that is configured to receive an actuator and insertion instrument <NUM>, as shown in <FIG>. The actuator and insertion instrument <NUM> can be configured to insert the cage <NUM> into the intervertebral space, and can further actuate the cage <NUM> from its first or insertion configuration to its second or expanded configuration in the manner described above. Further, the instrument <NUM> can cause the cage <NUM> to angulate in the manner described above. In particular, the actuation of each of the wedges <NUM> and <NUM> for translation towards the other of the wedges <NUM> and <NUM> can be achieved in the manner previously described above.

It is contemplated that the present embodiment may be particularly useful for achieving both distraction and angulation in the coronal plane, using one device. The cage <NUM> may be effective to restore sagittal balance, while still being less invasive, and due to its ability to be angulated in the coronal plane, is effective for treating degenerative scoliosis or to correct other coronal plane abnormalities. The cage <NUM> of the present disclosure can achieve these dual goals by providing two independently movable wedges <NUM> and <NUM> from the first or insertion configuration illustrated in <FIG>, in which the spring member <NUM> can be in a relaxed configuration. That is, the lattice structure <NUM> of the spring <NUM> can be relaxed and thus not apply a force to either of the upper and lower plates <NUM> and <NUM>. The wedges <NUM> and <NUM> may be moved by the same amount, to distract, as shown in <FIG>. As illustrated in <FIG>, when the intervertebral cage is in the second or expanded configuration with the second relative angular orientation equal to the first relative angular orientation, the lattice structure <NUM> of the spring <NUM> can be placed in tension along the transverse direction T. Thus, the lattice structure <NUM> applies a compressive force to the upper and lower endplates <NUM> and <NUM> along the transverse direction T that biases the upper and lower endplates <NUM> and <NUM> toward each other. The wedges <NUM> and <NUM> overcome the force as they move the cage <NUM> to the expanded configuration. Alternatively or additionally, referring now to <FIG>, one of the wedges <NUM> and <NUM> may be moved only to effect angulation only, or both wedges <NUM> and <NUM> may be moved a disproportionate amount so that there is both distraction and angulation. When the cage <NUM> is angulated, one longitudinal end of the lattice structure <NUM> can be placed in tension greater than the other longitudinal end of the lattice structure <NUM>. The other longitudinal end of the lattice structure <NUM> can be placed in compression or lesser tension, or can otherwise be neutral. Generally speaking, the amount of height increase or expansion of the cage <NUM> along the transverse direction T can be dependent on the implant height. In some embodiments, the expansion may be in the range of up to approximately <NUM>. Angulation can be in the range from about <NUM> degrees up to approximately <NUM> degrees, including from approximately <NUM> degrees to approximately <NUM> degrees.

As mentioned above, the intervertebral cages of the present disclosure are configured to be able to allow insertion through a narrow access path, but are able to be expanded and angularly adjusted so that the cages are capable of adjusting the angle of lordosis of the vertebral segments. By being able to angularly adjust and expand (or distract), the cages allow a very narrow anterior for insertion and a larger anterior after implantation to accommodate and adapt to larger angles of lordosis or kyphosis. Additionally, the cages can effectively restore sagittal balance and alignment of the spine, and can promote fusion to immobilize and stabilize the spinal segment.

With respect to the ability of the expandable cages to promote fusion, many in-vitro and in-vivo studies on bone healing and fusion have shown that porosity can facilitate vascularization, and that the desired infrastructure for promoting new bone growth should have a porous interconnected pore network with surface properties that are optimized for cell attachment, migration, proliferation and differentiation. At the same time, it is believed that cage's ability to provide adequate structural support or mechanical integrity for new cellular activity is another primary factor for achieving clinical success. Regardless of the relative importance of one aspect in comparison to the other, what is clear is that both structural integrity to stabilize, as well as the porous structure to support cellular growth, can assist in proper and sustainable bone regrowth.

The cages described herein can further take advantage of current additive manufacturing techniques that allow for greater customization of the devices by creating a unitary body that may have both solid and porous features in one. In some embodiments as shown, the cages can have a porous structure, and be made with an engineered cellular structure that includes a network of pores, microstructures and nanostructures to facilitate osteosynthesis. For example, the engineered cellular structure can comprise an interconnected network of pores and other micro and nano sized structures that take on a mesh-like appearance. These engineered cellular structures can be provided by etching or blasting to change the surface of the device on the nano level. One type of etching process may utilize, for example, HF acid treatment. These same manufacturing techniques may be employed to provide these cages with an internal imaging marker. For example, these cages can also include internal imaging markers that allow the user to properly align the cage and generally facilitate insertion through visualization during navigation. The imaging marker shows up as a solid body amongst the mesh under x-ray, fluoroscopy or CT scan, for example. The cages described herein can comprise a single marker, or a plurality of markers. These internal imaging markers greatly facilitate the ease and precision of implanting the cages, since it is possible to manufacture the cages with one or more internally embedded markers for improved visualization during navigation and implantation.

Another benefit provided by the implantable devices of the present disclosure is that they are able to be specifically customized to the patient's needs. Customization of the implantable devices is relevant to providing a preferred modulus matching between the implant device and the various qualities and types of bone being treated, such as for example, cortical versus cancellous, apophyseal versus central, and sclerotic versus osteopenic bone, each of which has its own different compression to structural failure data. Likewise, similar data can also be generated for various implant designs, such as for example, porous versus solid, trabecular versus non-trabecular, etc. Such data may be cadaveric, or computer finite element generated. Clinical correlation with, for example, DEXA data can also allow implantable devices to be designed specifically for use with sclerotic, normal, or osteopenic bone. Thus, the ability to provide customized implantable devices such as the ones provided herein allow the matching of the Elastic Modulus of Complex Structures (EMOCS), which enable implantable devices to be engineered to minimize mismatch, mitigate subsidence and optimize healing, thereby providing better clinical outcomes.

A variety of spinal implants may be provided by the present disclosure, including interbody fusion cages for use in either the cervical or lumbar region of the spine. Further, it is contemplated that the principles of this disclosure may be utilized in a cervical interbody fusion (CIF) device, a transforaminal lumbar interbody fusion (TLIF) device, anterior lumbar interbody fusion (ALIF) cages, lateral lumbar interbody fusion (LLIF) cages, posterior lumbar interbody fusion (PLIF) cages, and oblique lumbar interbody fusion (OLIF) cages.

Claim 1:
An expandable intervertebral cage (<NUM>), comprising:
a housing (<NUM>) having:
an upper housing portion (<NUM>) having an upper plate (<NUM>) and upper sidewalls (<NUM>) that extend out from the upper plate, wherein the upper plate defines an upper bearing surface configured for placement against an endplate of a first vertebral body; and
a lower housing portion (<NUM>) having a lower plate (<NUM>) and lower sidewalls (<NUM>) that extend out from the lower plate, wherein the lower plate defines a lower bearing surface configured for placement against an endplate of a second vertebral body, wherein the upper and lower sidewalls are configured to slide along each other; and
an expansion and angular adjustment mechanism disposed between the upper and lower plates, and configured to effect height and angular adjustment of the intervertebral cage, the expansion and angular adjustment mechanism comprising: <NUM>) a leading wedge and a trailing wedge (<NUM>, <NUM>) located at opposite ends of the housing, each wedge (<NUM>, <NUM>) having upper and lower engagement surfaces configured engage respective engagement surfaces (<NUM>, <NUM>) of the upper and lower sidewalls (<NUM>, <NUM>), and <NUM>) a driver component (<NUM>) connecting the wedges together and configured to move the wedges toward each other upon actuation of the driver component (<NUM>), thereby causing the engagement surfaces of the wedges to bear against the engagement surfaces of the sidewalls, thereby moving the upper and lower bearing surfaces away from each other;
wherein the driver component (<NUM>) is further configured to move the leading wedge toward the trailing wedge while forces between the trailing wedge and the housing cause the trailing wedge to remain stationary as the leading wedge moves toward the trailing edge, thereby causing the upper plate (<NUM>) to angulate relative to the lower plate (<NUM>).