STABILIZATION MEMBERS FOR EXPANDABLE INTERVERTEBRAL IMPLANTS AND ASSOCIATED SYSTEMS - Patent application

Abstract

The expandable intervertebral cage includes vertically opposed upper and lower plates and longitudinally opposed distal and proximal wedges disposed between the plates. The wedges define a slope that engages with complementary slopes of the upper and lower plates to increase the vertical distance between the plates. An actuator is located between the plates and defines a central longitudinal axis and is coupled to the wedges such that rotation of the actuator about the axis moves at least one of the wedges longitudinally relative to the other, thereby increasing the vertical separation distance. At least one locking component is insertable into a receptacle at least partially defined by the proximal wedge and configured to transition from an unlocked configuration in which the actuator is rotatable relative to the proximal wedge to a locked configuration in which the actuator is rotationally fixed relative to the proximal wedge.

Description

[Technical field]

[0001] The present invention relates to expandable intervertebral implants, and more particularly to structures and features for providing such implants with enhanced stability within the intervertebral space. [Background technology]

[0002] When a disc degenerates, removal of the disc is often desirable. Spinal fusion may be used to treat such conditions and involves replacing the degenerated disc with a device such as a cage or other spacer that restores the height of the disc space and allows bone to grow through the device and fuse the adjacent vertebrae. Spinal fusion attempts to restore normal spinal alignment, stabilize the spinal segments for proper fusion, create an optimal fusion environment, and allow early active mobilization by minimizing damage to the spinal vasculature, dura, and neural elements. When spinal fusion meets these objectives, healing is accelerated and patient function, comfort, and mobility are improved. Spacer devices that are forced into the disc space and allow bone to grow from adjacent vertebrae through the upper and lower surfaces of the implant are known in the art. Summary of the Invention [Problem to be solved by the invention]

[0003] Nonetheless, a need continues to exist for devices that stabilize spinal segments and create optimal space for spinal fusion procedures while minimizing procedural invasiveness. [Means for solving the problem]

[0004] According to one embodiment of the present disclosure, an expandable intervertebral cage includes upper and lower plates opposed to one another along a vertical direction, and proximal and distal wedges positioned between the plates and opposed to one another along a longitudinal direction substantially perpendicular to the vertical direction. The distal and proximal wedges each define an inclined surface configured to engage a complementary inclined surface of the plate in a manner that increases the vertical distance between the upper and lower plates. An actuator is positioned between the plates and defines a central axis oriented along the longitudinal direction. The actuator is coupled to the distal and proximal wedges such that rotation of the actuator about the central axis moves at least one of the wedges relative to the other wedge along the longitudinal direction in a distance-increasing manner. The cage includes at least one locking component insertable into a receptacle at least partially defined by the proximal wedge. The at least one locking component is configured to transition from an unlocked configuration, in which the actuator is rotatable about a central axis relative to the proximal wedge, to a locked configuration, in which the actuator is substantially rotationally fixed relative to the proximal wedge.

[0005] According to another embodiment of the present disclosure, an expandable intervertebral cage includes upper and lower plates opposed to one another along a vertical direction, and proximal and distal wedges located between the plates and opposed to one another along a longitudinal direction substantially perpendicular to the vertical direction. The distal and proximal wedges each define an inclined surface configured to engage a complementary inclined surface of the plate in a manner that increases the vertical distance between the upper and lower plates. An actuator is located between the plates and defines a central axis oriented along the longitudinal direction. The actuator is coupled to the distal and proximal wedges such that rotation of the actuator about the central axis moves at least one of the wedges relative to the other wedge along the longitudinal direction in a manner that increases the distance. The cage includes at least one locking component carried by the proximal wedge and configured to transition from an unlocked configuration in which the proximal wedge is longitudinally translatable relative to at least one of the plates to a locked configuration in which the proximal wedge is substantially longitudinally fixed relative to the at least one plate.

[0006] According to an additional embodiment of the present disclosure, an expandable intervertebral cage includes upper and lower plates opposed to one another along a vertical direction and a single wedge body having first and second sides opposed to one another along a transverse direction substantially perpendicular to the vertical direction. The first and second sides are substantially planar from a proximal end of the wedge body to a distal end of the wedge body. The first and second sides are configured to mate with respective planar surfaces defined along respective inner walls of the upper and lower plates. The single wedge body defines a plurality of angled rails extending outwardly from the first and second sides along a transverse direction. The angled rails are oriented at respective oblique angles with respect to a central axis of the cage oriented along a longitudinal direction. The plurality of angled rails are configured to follow respective plurality of angled guide channels defined along the inner walls of the upper and lower plates in a manner that increases the distance between the upper and lower plates along the vertical direction. The cage includes an actuator located between the upper and lower plates and extending along the central axis. The actuator is coupled to the wedge body such that rotation of the actuator about the central axis moves the wedge body along the longitudinal direction in a manner that increases the distance between the plates.

[0007] According to a further embodiment of the present disclosure, an expandable intervertebral cage includes upper and lower plates opposed to one another along a vertical direction, and proximal and distal wedges positioned between the plates and opposed to one another along a longitudinal direction substantially perpendicular to the vertical direction. The distal and proximal wedges each define an inclined surface configured to engage a complementary inclined surface of the plate in a manner that increases the vertical distance between the upper and lower plates. An actuator is positioned between the plates and defines a central axis oriented along the longitudinal direction. The actuator is coupled to the distal and proximal wedges such that rotation of the actuator about the central axis moves at least one of the wedges relative to the other wedge along the longitudinal direction in a manner that increases the distance. The cage includes at least one locking component configured to maintain the increased distance. The locking mechanism includes a ratchet assembly including a first plurality of ratchet teeth and a second plurality of ratchet teeth defined along a flexible ratchet support, where at least one tooth of the first plurality of ratchet teeth is configured to advance relative to the second plurality of ratchet teeth in a manner that continuously meshes with the first direction of movement over an increasing distance, and the second plurality of ratchet teeth is configured to prevent movement of the at least one tooth in a second direction of movement opposite the first direction of movement. [Brief description of the drawings]

[0008] The foregoing summary and the following detailed description of illustrative embodiments of the present application will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the features of the present application, illustrative embodiments are shown in the drawings. It should be understood, however, that the present application is not limited to the precise arrangements and instrumentalities shown. [Figure 1] 1 is a top view of an intervertebral implant positioned between adjacent vertebral bodies, according to one embodiment of the present disclosure. [Figure 2A] FIG. 1 illustrates a perspective view of an intervertebral implant having locking features for maintaining the expanded height of the implant, according to one embodiment of the present disclosure. [Figure 2B] FIG. 2B is a cross-sectional side view of the implant illustrated in FIG. 2A shown in a collapsed configuration. [Figure 2C] 2B is another cross-sectional side view of the implant illustrated in FIG. 2A, showing the implant in an expanded configuration. [Figure 2D] FIG. 2D is an enlarged view of a portion of the implant illustrated in FIG. 2C. [Figure 2E] FIG. 2E is a perspective view of the locking member illustrated in FIGS. 2B to 2D. [Figure 3A] 1 is a perspective view of an intervertebral implant receiving a locking member according to one embodiment of the present disclosure; [Figure 3B] 3B is a cross-sectional side view of the intervertebral implant illustrated in FIG. 3A showing a locking member coupled to the intervertebral implant. [Figure 4A] 1 is a cross-sectional side view of a portion of an intervertebral implant according to another embodiment of the present disclosure shown in a folded configuration with a locking member in an unlocked configuration. [Figure 4B] 4B is another cross-sectional side view of the implant illustrated in FIG. 4A showing the implant in an expanded configuration and the locking member in a locked configuration. [Figure 4C] FIG. 4C is a perspective view of the locking member illustrated in FIGS. 4A and 4B. [Figure 5A] 1 is a perspective view of an intervertebral implant having a locking member according to one embodiment of the present disclosure; [Figure 5B] 5B is a cross-sectional perspective view of the implant illustrated in FIG. 5A with the locking members shown in a locked configuration. [Figure 5C] FIG. 5B is a cross-sectional side view of a portion of the implant illustrated in FIG. 5A. [Figure 5D] 5B is a perspective view of select components of the locking mechanism of the implant illustrated in FIG. 5A shown in a locked configuration. [Figure 5E] FIG. 5E is a perspective view of the components illustrated in FIG. 5D shown in an unlocked configuration. [Figure 6] 13 is a cross-sectional perspective view of a portion of an intervertebral implant having a locking mechanism according to another embodiment of the present disclosure. FIG. [Figure 7A]13 is a proximal end view of an intervertebral implant with selected components removed illustrating a locking mechanism according to another embodiment of the present disclosure. FIG. [Figure 7B] FIG. 7B is a perspective view of the implant illustrated in FIG. 7A further showing a tool positioned to unlock the locking mechanism. [Figure 8] FIG. 13 is a cross-sectional perspective view of a proximal end of an intervertebral implant illustrating a locking mechanism according to another embodiment of the present disclosure. [Figure 9A] 13 is a plan view of a locking mechanism of an intervertebral implant according to another embodiment of the present disclosure. [Figure 9B] 9B is a cross-sectional side view of a portion of an intervertebral implant having a locking mechanism illustrated in FIG. 9A. [Figure 10A] FIG. 13 is a perspective view of a ratchet locking mechanism of an intervertebral implant according to another embodiment of the present disclosure. [Figure 10B] FIG. 10B is a perspective view of an intervertebral implant using a ratchet locking mechanism illustrated in FIG. 10A. [Figure 10C] FIG. 10C is a top view of the implant illustrated in FIG. 10B. [Figure 11] FIG. 13 is a cross-sectional perspective view of an intervertebral implant having a ratchet locking mechanism according to another embodiment of the present disclosure. [Figure 12] FIG. 13 is a perspective view of an intervertebral implant having a ratchet locking mechanism according to another embodiment of the present disclosure. [Figure 13] FIG. 13 is a perspective view of an intervertebral implant having a ratchet locking mechanism according to another embodiment of the present disclosure. [Figure 14A] FIG. 13 is a proximal end view of an intervertebral implant having a cam locking mechanism according to another embodiment of the present disclosure. [Figure 14B] 13 is a proximal end view of an intervertebral implant having another type of cam locking mechanism, according to another embodiment of the present disclosure. [Figure 14C] FIG. 14C is a cross-sectional side view of a portion of the implant illustrated in FIG. 14B. [Figure 15] 13 is a cross-sectional top view of a portion of an intervertebral implant having a spring locking mechanism according to another embodiment of the present disclosure. [Figure 16] FIG. 13 is a perspective view of an intervertebral implant having a locking mechanism according to another embodiment of the present disclosure. [Figure 17] FIG. 13 is a cross-sectional perspective view of an intervertebral implant having a traction-type locking mechanism according to another embodiment of the present disclosure. [Figure 18A] 1A-1C are plan views illustrating exemplary modes of relative motion between respective components of the intervertebral implant. [Figure 18B] 1A-1C are plan views illustrating exemplary modes of relative motion between respective components of the intervertebral implant. [Figure 19A] FIG. 13 is a perspective view of an intervertebral implant having another locking mechanism, according to an embodiment of the present disclosure. [Figure 19B] 19B is a perspective view of select components of the locking mechanism illustrated in FIG. 19A. [Figure 19C] FIG. 19B is a perspective cross-sectional view of the implant illustrated in FIG. 19A. [Figure 20A] FIG. 13 is a perspective view of an intervertebral implant having another locking mechanism, according to an embodiment of the present disclosure. [Figure 20B] 20B is a partial enlarged view of selected components of the locking mechanism illustrated in FIG. 20A. [Figure 20C] FIG. 25 is a perspective cross-sectional view of a portion of the locking mechanism illustrated in FIGS. 20A and 20B. [Figure 21A] FIG. 13 is a perspective view of an intervertebral implant having another locking mechanism, according to an embodiment of the present disclosure. [Figure 21B] 21B is a perspective view of select components of the locking mechanism illustrated in FIG. 21A. [Figure 21C] FIG. 21C is a perspective cross-sectional view of the locking mechanism illustrated in FIGS. 21A and 21B. [Figure 22A] FIG. 13 is a perspective view of an intervertebral implant having another locking mechanism, according to an embodiment of the present disclosure. [Figure 22B] FIG. 22B is an enlarged perspective view of a portion of the implant illustrated in FIG. 22A. [Figure 22C] FIG. 24 is a cross-sectional side view of a portion of the locking mechanism illustrated in FIGS. 22A and 22B. [Figure 23A]FIG. 13 is a perspective view of an intervertebral implant having a unitary wedge body for expanding the implant, shown in a collapsed configuration, according to another embodiment of the present disclosure. [Figure 23B] FIG. 23B is an exploded view of the implant illustrated in FIG. 23A. [Figure 23C] 23B is a perspective view of the implant illustrated in FIG. 23A shown in an expanded configuration. [Figure 23D] FIG. 23D is a cross-sectional side view of the implant shown in FIG. 23C. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The present disclosure may be more readily understood by reference to the following detailed description in conjunction with the accompanying drawings and examples, which form a part of this disclosure. It is to be understood that the present disclosure is not limited to the specific apparatus, method, application, conditions or parameters described and / or shown herein, and the terminology used herein is for the purpose of describing specific embodiments by way of example only, and is not intended to limit the scope of the present disclosure. Also, as used in the specification, including the appended claims, the singular forms "a", "an", and "the" include the plural, and reference to a particular numerical value includes at least that particular value, unless the context clearly dictates otherwise.

[0010] The term "plurality," as used herein, means more than one. When a range of values ​​is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values ​​are expressed in an approximation form, by use of "about," it will be understood that the particular value forms another embodiment. All ranges are inclusive and combinable.

[0011] As used herein with respect to dimensions, angles, ratios, and other geometric features, the terms "approximately," "about," and "substantially" take into account manufacturing tolerances. Additionally, the terms "approximately," "about," and "substantially" may include 10% greater or less than the stated dimension, ratio, or angle. Additionally, the terms "approximately," "about," and "substantially" may equally apply to the specific values ​​stated.

[0012] Terms such as first, second, etc. may be used herein to describe various elements, but it should be understood that these elements should not be limited by these terms. These terms are used to distinguish one element from another. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element, without departing from the scope of the embodiments disclosed herein.

[0013] The embodiments disclosed herein relate to expandable intervertebral implants, such as fusion cages, having features that enhance stabilization of the implant within the intervertebral space. The features disclosed herein enhance stabilization by various techniques, including fixing the relative positions between various components of the implant in a manner that effectively locks the implant at their desired expanded height. The stabilization techniques described herein also provide enhanced structural support between various components of the implant, such as by reducing relative motion between select components. Reducing relative motion between components provides numerous benefits, including commensurate reduction in wear and stress on the various components, thereby providing an enhanced healing environment for the patient.

[0014] With reference to FIG. 1 , the upper vertebral body 2 and the adjacent lower vertebral body 4 define an intervertebral space 5 extending between the vertebral bodies 2 and 4. The upper vertebral body 2 defines an upper vertebral surface 6, and the adjacent lower vertebral body 4 defines an inferior vertebral surface 8. The vertebral bodies 2, 4 may be anatomically adjacent vertebral bodies or may be the remaining vertebral bodies after an intermediate vertebral body has been removed from the region between the vertebral bodies 2 and 4. The intervertebral space 5 in FIG. 1 is illustrated following a discectomy procedure in which disc material has been removed, or at least partially removed, to prepare the intervertebral space 5 for receiving an expandable intervertebral implant 10. The implant 10 may be configured for use in various regions of the spine, including any of the cervical, lumbar, sacral, and thoracic regions. The implant 10 may also be configured for implantation along various insertion trajectories or "approaches" into the intervertebral space. In the illustrated example, the implant 10 is inserted along an anterior approach (i.e., from an anterior region of the patient's anatomy toward a posterior region of the anatomy). In other exemplary embodiments, the implant 10 may be inserted along an alternative approach, such as, by way of non-limiting examples, a lateral approach, a posterior approach, or a percutaneous approach. It should be understood that the implant 10 may also be indicated for various types of intervertebral procedures including, by way of non-limiting examples, spinal fusion procedures such as Anterior Lumbar Interbody Fusion (ALIF), Transforaminal Lumbar Interbody Fusion (TLIF), Posterior Lumbar Interbody Fusion (PLIF), lumbar fusion, or other surgeries for treating Degenerative Disc Disease (DDD), surgeries for treating Degenerative Spinal Deformity (Def / Deg), minimally invasive surgeries (MIS), and interbody surgeries.Once inserted into the intervertebral space 5, the implant 10 can be expanded in a cranial-sacral direction to achieve the appropriate height restoration and / or lordosis. The intervertebral space 5 can be disposed anywhere along the spine, including the lumbar, thoracic, and cervical regions of the spine, as desired.

[0015] In the following description, certain terminology is used merely for convenience and is not limiting. The terms "right", "left", "lower", and "upper" designate directions within the drawings to which reference is made. The terms "inner", "internal", and "interior" refer to directions toward the geometric center of the implant, while the terms "outer", "external", and "exterior" refer to directions away from the geometric center of the implant. The terms "anterior", "posterior", "upper", "lower", "inner", "outer", and related terms and / or phrases are used to designate various positions and orientations within the human body to which reference is made. When these words are used in connection with the implant 10 or components thereof, they should be understood to refer to the relative position of the implant 10 implanted within the body as shown in FIG. 1. The terms include the words listed above, derivatives thereof, and words of similar meaning.

[0016] 2A, the implant 10 is described herein as extending horizontally along a longitudinal direction L and a transverse direction T, and vertically along a vertical direction V. Unless otherwise specified herein, the terms "longitudinal," "transverse," and "vertical" are used to describe the orthogonal components of the various implant components and implant component axes. It should be understood that the longitudinal direction L and the transverse direction T are illustrated as extending along and defining a horizontal plane (also referred to herein as the "longitudinal-transverse plane LT"), while the vertical direction is illustrated as extending along a vertical plane (such as either the "vertical-longitudinal plane VL" or the "vertical-transverse plane VT," as each referred to herein), and that the plane encompassing the various directions may vary during use. For example, when implant 10 is inserted into intervertebral space 5, vertical direction V generally extends along a superior-inferior (or sacral-cranial) direction, while the horizontal plane generally lies within an anatomical plane defined by an anterior-posterior direction and a medial-lateral direction. Thus, the directional terms "vertical" and "horizontal" may be used to describe illustrative implant 10 and its components solely for purposes of clarity and illustration.

[0017] In FIG. 2A , the implant 10 is shown in a folded configuration C. The implant 10 can extend between a proximal or posterior end 12 and a distal or anterior end 14, which is spaced apart from the anterior end 14 along a longitudinal implant axis X1 extending along a longitudinal direction L. The anterior end 12 and the posterior end 14 of the implant 10 can be so designated because the anterior end can be inserted into the intervertebral space 5 first. The posterior end 12 can be configured to couple with one or more insertion instruments configured to support and carry the implant 10 within the intervertebral space 5. The implant 10 can also extend along a transverse direction T between a first side 16 and an opposing second side 18.

[0018] The implant 10 may include a first or upper plate 100 and a second or lower plate 200 opposing the upper plate 100 along a vertical direction V. The upper plate 100 may define an upper plate body 102 defining an upper or first bone contacting surface 104, and the lower plate 200 may define a lower plate body 202 defining a lower or second bone contacting surface 204 spaced apart from the first bone contacting surface 104 along the vertical direction V. The upper and lower bone contacting surfaces 104, 204 may be configured to engage opposing upper and lower vertebral bodies 4 and 6, respectively. Each bone contacting surface 104, 204 may extend in a substantially convex manner, as shown. The bone contacting surfaces 104, 204 may be convex along both the longitudinal direction L and the transverse direction T, although in other embodiments the bone contacting surfaces 104, 204 may have a convex profile along only one of the longitudinal direction L and the transverse direction T, and in still other embodiments the bone contacting surfaces 104, 204 may be substantially planar. The bone contacting surfaces 104, 204 may also at least partially define a texture (not shown), such as spikes, ridges, pyramids, spines, depressions, or protuberances, which are configured to engage the respective vertebral bodies 4 and 6 when the implant 10 is inserted into the intervertebral space 5.

[0019] As used herein, the term "distal" and its derivatives means a direction from the posterior end 12 toward the anterior end 14. As used herein, the term "distal" and its derivatives means a direction from the anterior end 14 toward the posterior end 12. Thus, the implant 10 extends along a proximal direction P from the anterior end 14 to the posterior end 12, and the implant 10 also extends along a distal direction D from the posterior end 12 toward the anterior end 14. It should be understood that the proximal direction P and the longitudinal direction D are each unidirectional components of a longitudinal direction, which is bidirectional.

[0020] As used herein, the term "superior" and its derivatives refer to a direction from the second bone contacting surface 204 toward the first bone contacting surface 104. As used herein, the term "inferior" and its derivatives refer to a direction from the first bone contacting surface 104 toward the second bone contacting surface 204. Thus, as used herein, the term "vertical direction V" is bidirectional and is defined by one upward direction and an opposing downward direction.

[0021] 2B and 2C, the implant 10 can include an expansion mechanism 300 interposed between portions of the upper plate 100 and the lower plate 200 and configured to separate the upper plate 100 and the lower plate 200 relative to one another along the vertical direction V. For example, the expansion mechanism 300 can be configured to actuate the implant 10 from a collapsed configuration C, as shown in FIG 2B, to an expanded configuration E, as shown in FIG 2C.

[0022] The upper plate 100 and the lower plate 200 can each define features configured to accommodate components of the expansion mechanism 300. For example, the upper plate 100 and the lower plate 200 can define respective cavities, voids, lumens, spaces, etc. that are configured to accommodate and / or interact with respective features of the expansion mechanism. Thus, it should be understood that portions of the upper plate 100 and the lower plate 200 that interact with respective features of the expansion mechanism, e.g., their interior surfaces, can themselves be characterized as being features of the expansion mechanism. Stated another way, the expansion mechanism can include portions of the upper plate 100 and the lower plate 200.

[0023] The expansion mechanism 300 includes an actuator 302 that can be elongated along a longitudinal direction L. The actuator 302 is configured to press one or more lift bodies 304 of the expansion mechanism 300 against associated portions of one or both of the upper and lower plates 100 and 200 to move at least one of the upper and lower plates 100 and 200 along a vertical direction V away from the other of the upper and lower plates 100 and 200. In this manner, the actuator 302 is configured to drive a vertical expansion of the upper and lower plates 100 and 200, thereby increasing a height H measured between the respective portions of the first and second bone contacting surfaces 104 and 204. In particular, the actuator 302 and the one or more lift bodies 304 are configured to increase the height from a first or minimum height H measured when the implant 10 is in the collapsed configuration C (FIG. 2B) to a second or maximum height H measured when the implant 10 is in the expanded configuration E (FIG. 2C). It should be appreciated that the expansion mechanism 300 may be configured to control expansion to virtually any height between a minimum height and a maximum height.

[0024] The actuator 302 is configured to move one or more lift bodies 304 in a manner that presses or otherwise pushes against associated portions of one or both of the upper plate 100 and the lower plate 200 to drive the expansion of the implant 10 (i.e., to increase the height between the first bone contacting surface 104 and the second bone contacting surface 204). In this illustrated exemplary embodiment, the actuator 302 is a shaft configured to rotate about a central axis that may be a longitudinal implant axis X1. It should be understood that the axis X1 may also be referred to as a "shaft axis" X1. The shaft 302 has one or more transmission structures 306 configured to transmit the rotational movement of the shaft 302 to another mode of movement to the lift body 304. In this embodiment, the one or more lift bodies 304 include a pair of wedges 304 that engage the shaft 302. The wedges 304 define respective channels, which in this example are bores 308 through which the shaft 302 extends. Within the bore 308, the interior surfaces of the wedges 304 define complementary transmission structures 310 configured to engage with the transmission structures 306 of the shaft 302. In this exemplary embodiment, the transmission structures 306 of the shaft 302 are external threads 306 and the transmission structures 310 of the wedges 304 are internal threads 310 configured to threadingly engage (i.e., mate) with the external threads 306 of the shaft 302. In this manner, the complementary external threads 306 of the shaft 302 and the internal threads 310 of the wedges 304 are configured to transmit rotational movement of the shaft 302 about the axis X1 to translational movement of the wedge 304 along the longitudinal direction L. As shown, the external threads 306 can be disposed along a first or proximal threaded region 312 and a second or distal threaded region 314 of the shaft 302. The first and second threaded regions 312, 314 can be spaced apart from one another, such as on opposite sides of a guide feature 316 of the shaft 302.

[0025] In the illustrated embodiment, the threads 306 of the first threaded region 312 and the second threaded region 314 can extend along opposing thread paths such that upon rotation of the shaft 302 about the axis X1, the pair of first or proximal and second or distal wedges 304 translate in opposite directions along the longitudinal direction L. For example, as shown, the proximal and distal wedges 304 can be located at opposing ends 318, 320 of the shaft 302 in the collapsed configuration C and can move towards each other during expansion. However, in other embodiments in which the first threaded region 312 and the second threaded region 314 extend along opposing thread paths, the threads 306 can be configured to translate the wedges 304 away from each other during expansion, such as from a central starting position adjacent the guide arrangement 316 and therefrom towards the opposing ends 318, 320 of the shaft 302. In yet other embodiments, the threads 306 of the first threaded region 312 and the second threaded region 314 can extend along substantially similar thread paths that cause the wedge 304 to translate in the same direction in response to rotation of the shaft 302. Moreover, as in the illustrated embodiment, the threads 306 of the first threaded region 312 and the second threaded region 314 can have substantially equal thread pitches such that the wedge 304 translates at the same rate in response to rotation of the shaft 302. However, in other embodiments, the threads 306 of the first threaded region 312 and the second threaded region 314 can have different thread pitches such that the wedge 304 translates at different rates in response to rotation of the shaft 302.

[0026] 2A , each wedge 304 extends from a first or outer end 322 to a second or inner end 324 along a longitudinal direction L. Each wedge 304 also extends from a first side 326 to a second side 328 opposite each other along a transverse direction T. The wedge 304 also has one or more pressing surfaces 330 that abut one or more complementary contact surfaces 332 of the upper plate 100 and / or lower plate 200. In the illustrated embodiment, each wedge 304 has an upper pressing surface 330 and a lower pressing surface 330 spaced apart from each other along a vertical direction V. The pressing surfaces 330 may each be inclined relative to the vertical direction V. The complementary contact surfaces 332 of the upper plate 100 and / or lower plate 200 are inclined in a complementary manner to the respective pressing surfaces 330 of the wedge 304. The wedge 304 may also include one or more guide arrangements 334 configured to run along one or more complementary guide channels 336 in the upper plate 100 and / or lower plate 200 to guide the translational movement of the wedge 304 relative to the upper plate 100 and lower plate 200 and to further guide the vertical expansion of the plates 100, 200. For example, in this embodiment, the wedge 304 may include upper and lower guide arrangements 334, which may be upper and lower protrusions 334 extending outwardly from the respective pushing surfaces 330 along the vertical direction V. The guide arrangements 334 may run along complementary guide channels 336 that extend into the upper plate 100 and lower plate 200 from the respective contact surfaces 332. As shown, the guide arrangements 334 and the complementary guide channels 336 may have interdigitating dovetail geometries.

[0027] The upper plate 100 and the lower plate 200 can define a vertical bore 106, 206 extending vertically through the plates 100, 200 and having openings at the first bone contacting surface 104 and the second bone contacting surface 204, respectively. The bore 106, 206 can optionally receive bone graft or other bone growth inducing material, such as after expansion of the implant 10. The guide arrangement 316 of the shaft 302 can include a flange structure, such as a pair of longitudinally spaced flanges 338 located on either side of an annular recess 340. One or both of the upper plate 100 and the lower plate 200 can define a guide projection 342 configured to ride along the annular recess 340 during implant expansion. In this manner, the guide projection 342 and the annular recess 340 can further guide the vertical expansion of the upper plate 100 and the lower plate 200 away from each other. The upper and lower end plates 100, 200 can include additional guide structures. For example, one of the plates 100, 200 can define a vertical extension 346 configured to run along a complementary vertical channel 348 in the other of the plates 100, 200. Other guide structures are within the scope of this disclosure.

[0028] The shaft 302 defines a drive feature, such as a socket 344 located at a proximal end 318 of the shaft 302. The socket 344 is configured to receive a drive force, such as a rotational drive force, such as a drive torque, from a drive member, such as a drive bit, which may be manually or electrically powered. Rotation of the shaft 302 about axis X1 causes the wedge 304 to ride along the first threaded region 312 and the second threaded region 314 of the shaft 302, causing the pushing surface 330 of the wedge 304 to ride along and press against the complementary contact surfaces 332 of the upper and lower plates 100, 200, thereby driving the plates 100, 200 away from each other along the vertical direction V, thereby expanding the implant 10. During expansion, the guide arrangement 334 also follows along the complementary guide channels 336 in the upper and lower plates 100, 200 while the guide arrangement 334 may also press against the surfaces of the guide channels 336 in a manner that further pushes the plates 100, 200 away from one another. It should be understood that the implant 10 and various components thereof may be constructed as described in further detail in any of U.S. Patent No. 8,105,382, issued on January 31, 2012 to Olmos et al., and U.S. Patent No. 9,717,601, issued on August 1, 2017 to Miller, the entire disclosures of which are incorporated herein by reference.

[0029] The expansion mechanism 300 is configured such that after the implant 10 has expanded to the desired height H, the expansion mechanism 300 may be effectively "locked" or otherwise fixed in place to maintain the expanded height H. As shown in FIGS. 2B-2E, the expansion mechanism 300 may include at least one locking member for locking the expansion mechanism 300 in place at the desired height H. In this embodiment, the at least one locking member is a nut 350, such as a jam nut, that is threaded onto the shaft 302 at its proximal end 318 and configured to abut a portion of the proximal wedge 304 in a manner that resists proximal movement of the proximal wedge 304, thereby fixing the relative position of the wedge 304 with respect to the shaft 302, thus locking the expansion mechanism 300 in place, thereby securing the implant at the expanded height H. The jam nut 350 can be disposed along the first threaded region 312 and can extend into a locking receptacle 352 of the proximal wedge 304. The locking receptacle 352 can be in communication with the bore 308 of the proximal wedge 304. The locking receptacle 352 can include a first or proximal receptacle portion 354 and a second or distal receptacle portion 356. The distal receptacle portion 356 can define an inner diameter D2 that is smaller than the inner diameter D1 of the proximal receptacle portion 354. In this embodiment, the proximal receptacle portion 354 can define an internal thread 358 and the distal receptacle portion 356 can be without threads. An inner diameter D1 of the proximal receptacle portion 354 may be defined as the minor thread diameter of the internal threads 358 (i.e., measured at the apex of the internal threads 358). The distal receptacle portion 356 may define a distal end face 360 ​​of the locking receptacle 352. The distal end face 360 ​​may provide a distal abutment surface for the jam nut 350. A shoulder surface 362 at the distal end of the proximal receptacle portion 354 may provide an intermediate abutment surface for the jam nut 350.

[0030] Jam nut 350 can be configured to threadingly engage external threads 306 of shaft 302, particularly proximal threaded region 312 thereof, and to reside within locking receptacle 352 of proximal wedge 304. Jam nut 350 can define a central bore 351 and internal threads 353 therein that are configured to threadingly engage threads of proximal threaded region 312 of shaft 302. Jam nut 350 can be configured to reside within proximal receptacle portion 354 and distal receptacle portion 356 in a nested manner. For example, jam nut 350 can include a proximal nut portion 364 configured to reside within proximal receptacle portion 354, and can further include a distal nut portion 366 configured to reside within distal receptacle portion 356. The proximal nut portion 364 can define a proximal end 368 of the nut, and the distal nut portion 366 can define a distal end 370 of the nut 350. A distal shoulder surface 371 of the proximal nut portion 364 can be configured to abut an internal shoulder surface 362 in the locking receptacle 352. The proximal nut portion 364 can define external threads 372 configured to threadingly engage the external threads 358 of the proximal receptacle portion 354. The distal nut portion 366 can be smooth and devoid of external threads. The proximal nut portion 364 can define an outer diameter that is larger than the outer diameter defined by the distal nut portion 368. The outer diameter of the proximal nut portion 364 can be defined as a lead thread diameter of the external threads 372.

[0031] Jam nut 350 may be "integral" within locking receptacle 352 of proximal wedge 304, meaning that once jam nut 350 is advanced within proximal and distal receptacle portions 354, 356 in a nested manner, proximal wedge 304, jam nut 350, and shaft 302 may be cooperatively configured to retain jam nut 350 therein. For example, jam nut 350 may be retained within locking receptacle 352 as a result of the thread pitch differential of (1) the thread interface between nut external threads 372 and internal threads 358 of proximal wedge 304, and (2) the thread interface between nut internal threads 353 and the threads of proximal threaded region 312 of shaft 302. It should be understood that proximal wedge 304 may use other types of retention features to retain jam nut 350 therein.

[0032] The proximal nut portion 364 can define one or more mounting arrangements for coupling with a tool, such as a nut insertion tool, such as a tool similar to nut insertion tool 380 described below with reference to FIG. 3A. For example, with continued reference to FIGS. 2B-2D, the proximal nut portion 364 can define a plurality of receptacles 376 that can be circumferentially spaced between associated proximally extending mounting projections 377. As shown, the receptacles 376 can be arranged in a cross pattern and configured to receive complementary mounting teeth 382 defined in a distal end 384 of the tool 380. The complementary geometries of the receptacles 376 and teeth 382 can be configured such that the jam nut 350 is secured to the distal end 384 of the tool 380 during insertion of the jam nut 350 in the locking receptacle 352 by the tool 380. The complementary geometric shapes of the receptacle 376 and teeth 382 are further configured such that the tool 380 can rotate the jam nut 350 about a central tool axis collinear with the shaft axis X1 to threadingly engage the external threads 372 of the nut 350 along the internal threads 358 of the proximal receptacle portion 354 until the external threads 372 distally pass the internal threads 358, at which point the internal retaining surface 374 retains the jam nut 350 within the proximal receptacle portion 354.

[0033] The mounting protrusions 377, or at least a portion thereof, may optionally have some degree of flexibility, such that, for example, when the external threads 372 pass distally over the internal threads 358, such flexible portions of the mounting protrusions 377 may flex radially outwardly to further retain the jam nut 350 within the locking receptacle 352. Additionally, such flexible portions of the mounting protrusions 377 may generate audible and / or tactile feedback, such as a click, as they flex radially outwardly, thereby alerting a technician that the jam nut 350 is retained within the locking receptacle 352.

[0034] After the jam nut 350 is retained in the locking receptacle 352, the tool 380 can be withdrawn by simply translating the tool 380 in a proximal direction. After the jam nut 350 is retained within the proximal receptacle portion 354, the inner retention surface 374 threadably advances the jam nut 350 along the proximal threaded region 312 of the shaft 302 simultaneously with the proximal wedge 304 in response to rotation of the shaft 302 about the shaft axis X1. In this manner, once the implant 10 has expanded to the desired height H, the jam nut 350 remains in abutting contact against the proximal wedge 304, such as at one or both of the distal end face 360 ​​and shoulder face 362 within the locking receptacle 352, thereby preventing the proximal wedge 304 from retracting along the shaft 302, thereby securing the implant 10 at the desired height H.

[0035] 3A and 3B, in other embodiments, the jam nut 350 may be removed or "disjointed." In such embodiments, the proximal nut portion 364 of the jam nut 350 may define an outer surface 378 that is devoid of external threads. The outer surface 378 may be substantially smooth and may define an outer diameter of the proximal nut portion 364. It should be understood that the jam nut 350 of this embodiment may otherwise be substantially similar to the jam nut 350 described above with reference to FIGS. 2B-2D. In this embodiment, the outer diameter of the proximal nut portion 364 may be smaller than the inner diameter D1 of the proximal receptacle portion 354 (which, as noted above, is the inner diameter of the internal threads 358). In such embodiments, the insertion tool 380 may insert the jam nut 350 into the locking receptacle 352 after the shaft 302 has been rotated to expand the implant 10 to the desired height H. In particular, the insertion tool 380 may advance the jam nut 350 within the locking receptacle 352, such as by rotating the nut 350 into threading engagement with the shaft's proximal threaded region 312, until the nut 350 distally abuts the proximal wedge 304, such as at one or both of a distal end face 360 ​​and a shoulder face 362 within the locking receptacle 352. Once abutting contact is made, the tool 380 may be withdrawn proximally. Further, as discussed above, when the jam nut 350 distally abuts the proximal wedge 304, the jam nut 350 prevents the proximal wedge 304 from threadingly backing out along the shaft 302, thereby securing the implant 10 at the desired height H1.

[0036] 4A and 4B, in other embodiments, the at least one locking member can be a collet 400 configured for insertion with the locking receptacle 352. The collet 400 defines a proximal portion 402 and a distal portion 404. The proximal portion 402 defines one or more mounting arrangements, such as recesses 405 and associated mounting projections 406, circumferentially spaced from one another in an alternating manner. The recesses 405 and mounting projections 406 can be configured to couple with a tool, such as a tool generally similar to the tool 380 described above. The collet 400 can also define an external thread 407, such as along the proximal portion 402. The distal portion 404 of the collet 400 can define a plurality of gaps or notches 408 spaced around the circumference of the collet 400 to define a plurality of extensions or legs 410 spaced circumferentially between the gaps 408. The outer surfaces 412 of the legs 410 preferably taper radially inward in the distal direction such that the outer diameter of the distal collet portion 404 decreases toward the distal end 414 of the collet 400. The legs 410 can define an inner clamping surface 416 adjacent the distal end 414 of the collet 400, which can be configured to press radially inward against the shaft 302, as described in more detail below. The inner clamping surface 416 can define an inner diameter that is substantially equal to, but slightly larger than, the main thread diameter of the proximal threaded region 312, at least when the collet 400 is in a neutral configuration.

[0037] The collet 400 may also define an inner flank 418 that may be located between the distal end 414 and the proximal end 420 of the collet 400. The flank 418 preferably has an inner diameter larger than the inner diameter of the clamping surface 416. The collet 400 may also define an inner guide surface adjacent the proximal end 420. When the collet 400 is in the neutral configuration, the inner clamping surface 416 may translate across and along the apex of the external threads 306 of the proximal threaded region 312.

[0038] The proximal wedge 304 may define a locking receptacle 452 generally similar to the locking receptacle 352 described above. However, in this embodiment, the locking receptacle 452 may include a proximal receptacle portion 454 and a distal receptacle portion 456, and an intermediate receptacle portion 458 located longitudinally between the proximal receptacle portion 454 and the distal receptacle portion 456. Within the distal receptacle portion 456, the inner surface 402 of the proximal wedge 304 tapers radially inward in the distal direction in a manner complementary to the tapered outer surface 412 of the leg 410. Thus, the inner diameter of the inner surface decreases along the distal direction. The proximal wedge 304 can define internal threads 460 within the locking receptacle 452, for example along its intermediate receptacle portion 458. Within the proximal receptacle portion 454, the wedge 304 can define an interior surface 462 that is substantially devoid of internal threads.

[0039] The collet 400 is configured to be insertable into the locking receptacle 452 and to advance distally therein from a neutral configuration to a locked configuration. For example, FIG. 4A shows the collet 400 in the neutral configuration, where the external threads 407 of the collet 400 are substantially within the proximal receptacle portion 454 and do not engage the internal threads 460 in the locking receptacle 452. The collet 400 can reside within the locking receptacle 452 in the neutral configuration while the shaft 302 rotates to advance the wedge 304, thereby expanding the implant 10. The collet 400 can be configured such that while in the neutral configuration, the shaft 302 can freely rotate relative to the collet 400 about a first rotational direction that expands the implant 10, such as a clockwise direction. After the implant 10 has been expanded to the desired height H, the collet 400 may be advanced distally within the distal receptacle portion 456 to transition from the neutral configuration to the locked configuration with the shaft 302. During this transition, the collet 400 may be rotated via the tool such that the external threads 407 of the collet 400 threadingly engage and advance along the internal threads 460 in the locking receptacle 452, which also advances the collet 400 distally relative to the shaft 302. Advancing the collet 400 distally in this manner advances the collet legs 410 into the distal receptacle portion 454.

[0040] The collet legs 410 are preferably configured such that, as the collet 400 is advanced distally within the locking receptacle 452 and relative to the shaft 302, the tapered outer surface 412 of the legs 410 contact the tapered inner surface 402 of the distal receptacle portion 456. As the collet 400 is advanced further distally, the tapered inner surface 402 urges the legs 410 radially inward, causing the inner clamping surfaces 416 to clamp against the shaft 302 with sufficient clamping force to effectively lock the collet 400 to the shaft 302 and further lock the collet 400 to the proximal wedge 304. In this manner, the collet 400 can effectively lock the proximal wedge 304 to the shaft 302, thereby securing the implant 10 at the desired height H1. The clamping force can cause plastic deformation of the shaft external threads 306 and / or the inner clamping surfaces 416 of the legs 410, thereby creating a locking press or compression fit between the collet legs 410 and the shaft 302. The clamping force can also cause the proximal portion 402 of the collet 400 to bend outwardly, which can press the collet external threads 407 radially outward against the internal threads 460, thereby increasing the locking engagement between the collet 400 and the proximal wedge 304.

[0041] The collet 400 can be integrated within the locking receptacle 452, meaning that the collet 400 and the locking receptacle 452 can be cooperatively configured to retain the collet 400 therein. For example, a proximal end portion of the locking receptacle 452 can include a retaining feature, such as one or more circumferential lips 464 extending radially inward from an inner surface 462. The one or more circumferential lips 464 can have respective proximal sides having an internal thread-like profile such that the collet external threads 407 can threadingly engage and then pass through the lip 464 as the collet 400 is inserted distally into the locking receptacle 452. However, a distal side of the one or more circumferential lips 464 can have a geometry configured to prevent the collet 400 from backing out of the locking receptacle 452. It should be understood that in other embodiments, collet 400 can be a separate, detached component, where collet 400 can separate from implant 10 during expansion and then be insertable into locking receptacle 452 after implant 10 has expanded to the desired height H and is in the locked configuration.

[0042] 5A-5E, an exemplary embodiment of an expandable implant 500 is shown in which at least one locking member includes a biased locking member, such as a spring-loaded locking plunger 502. The implant 500 may be generally similar to the implant 10 described above. For brevity, the following disclosure will focus primarily on the differences of the implant 500 relative to the implant 10 described above. The locking plunger 502 may be accessible and actuable through an access slot 504 defined by the proximal wedge 304.

[0043] The expansion mechanism 300 of this embodiment can include a guide hub 516 located longitudinally between the wedges 304. The guide hub 516 can be a separate component from the shaft 302 and the upper and lower plates 100 and 200, although in other embodiments, the guide hub 516 can be an integral extension of one of the upper and lower plates 100 and 200. The guide hub 516 can define a bore 518 through which the shaft 302 extends. The guide hub 516 can define one or more guide structures for guiding the expansion of the implant 500 along the vertical direction V. One such guide structure can be the general shape of the guide hub 516, which can be generally rectangular and / or block-like, and can have opposing sides 520 along the transverse direction T. The sides 520 of the guide hub 516 can translate along complementary inner surfaces 522 of the upper and / or lower plates 100 and / or 200. The guide hub 516 can also define one or more additional vertically oriented guide structures, such as a pair of rails 524 that project outwardly from the side surface 520 and are received in complementary guide channels 526 defined in the upper and lower plates 100, 200. The complementary rails 524 and guide channels 526 can guide the expansion of the upper and lower plates 100, 200 along the vertical direction V and can also maintain the relative longitudinal position between the guide hub 516 and the plates 100, 200 during expansion. It should be understood that other guide structures are within the scope of the present disclosure.

[0044] Similar to the above-described embodiment, the distal wedge 304 can define internal threads 310 that threadingly engage the distal threaded region 314 of the shaft 302. However, as shown in FIG. 5B, in this embodiment, the proximal threaded region 312 of the shaft 302 can threadingly engage internal threads 528 defined in the bore 518 of the guide hub 516. The proximal wedge 304 can be coupled to a proximal unthreaded region 530 of the shaft 302 that extends longitudinally between a proximal head 532 of the shaft 302 and the proximal threaded region 312. The head 532 of the shaft 302 can define various attachment configurations for coupling the shaft 302 to the proximal wedge 304 and the locking plunger 502. 5B-5E, for example, the head 532 can include a first flange 534, a second flange 536 spaced distally from the first flange 534, and an annular receptacle 538 located longitudinally between the first flange 534 and the second flange 536. The head 532 can be configured to reside within a locking receptacle 552 defined within the bore 308 of the proximal wedge 304. A retaining member, such as a retaining clip 560, can reside within the annular receptacle 538 of the head 532 (i.e., between the flanges 534, 536) and can also reside within an annular receptacle portion 555 of the locking receptacle 552 of the proximal wedge 304. The head 532 and retaining clip 560 can have a complementary geometry with the locking receptacle 552 of the wedge 304 to maintain the relative longitudinal position between the proximal wedge 304 and the head 532 (and thus between the proximal wedge 304 and the shaft 302). For example, as best shown in FIG. 5C , the second flange 536 of the head 532 can abut a distal shoulder surface 562 of the wedge 304 within the locking receptacle 552. The retaining clip 560 can fit snugly between the flanges 534, 536 of the head 532 and can also be configured to abut a proximal shoulder surface 564 at the proximal end of the annular receptacle portion 555.Thus, the second flange 536 can substantially prevent the proximal wedge 304 from translating proximally relative to the shaft 302, and the retaining clip 560 can substantially prevent the proximal wedge 304 from translating distally relative to the shaft 302. In this manner, rotation of the shaft 302 in this embodiment can cause the distal wedge 304 to translate proximally along the distal threaded region 314 while the proximal threaded region 312 advances distally along the internal threads 528 in the bore 518 of the guide hub 516, thereby causing the proximal wedge 304 to also advance distally along the shaft 302 relative to the guide hub 516 and the upper and lower plates 100, 200, thereby also causing the implant 10 to expand along the vertical direction V.

[0045] 5B and 5C , the locking plunger 502 can also be configured to reside within a locking receptacle 552 and be configured to engage the head 532 in a locking manner, as described in more detail below. A distal portion 550 of the bore 308 of the proximal wedge 304 can be sized to provide an annular gap 448 between the distal bore portion 550 and the unthreaded proximal region 530 of the shaft 302. A distal extension 553 of the locking plunger 502 can extend into the gap 448 and can engage a biasing member 554, which can be configured to bias the locking plunger 502 into locking engagement with the head 532. The biasing member 554 may be a spring, such as a compression coil spring 554 extending between a first push surface 556 defined at the distal end of the distal extension 553 and an opposing second push surface 558 which may be defined at the proximal end of the proximal threaded region 312 of the shaft 302.

[0046] 5D and 5E, the second flange 536 can define a plurality of recesses 540 spaced about the circumference of the second flange 536. Each of the recesses 540 effectively provides the second flange 536 with a plurality of projections or teeth 542 extending between adjacent ones of the recesses 540 about the circumference of the second flange 536. The spring 554 is configured to bias the locking plunger 502 proximally such that when the recesses 540 are rotationally aligned with the locking arms 570, the locking plunger 502 advances within the recesses 540. When the locking arms 570 are within the recesses 540, the shaft 302 is substantially prevented from rotating, thereby fixing the longitudinal position of the wedge 304 relative to the shaft 302, and thereby fixing the implant 500 at the associated height H. Thus, when the locking arm 570 is within the recess 540, the locking plunger 502 is in a locked position. To disengage the locking arm 570 from the recess 540, thereby moving the plunger 502 to the unlocked position, an unlocking tool having one or more detent features, such as a push arm, can be configured to extend into the access slot 504 of the proximal wedge 304 and push the locking arm 570 distally with sufficient force to overcome the biasing force provided by the spring 554, thereby pushing the locking arm 570 out of engagement with the recess 540, at which point the shaft 302 can be rotated to drive the expansion of the implant 500.

[0047] It should be understood that the unlocking tool may be part of a multi-component instrument for expanding the implant 500. For example, the unlocking tool may have an elongated tubular body including a push arm at its distal end. The tubular body may define a lumen through which a driving tool of the instrument may be advanced to couple with the shaft 302, such as in the socket 344. In such a position, with the unlocking tool pushing the locking plunger 502 into the unlocked position, the driving tool may be driven to rotate the shaft 302 to expand the implant 500 to a desired height H. Once the implant 500 has expanded to or near the desired height, the unlocking tool may be withdrawn a distance to remove the counter force against the biasing force of the spring 554. When the recess 540 of the second flange 536 is rotationally aligned with the locking arm 570, the locking arm 570 may extend into the recess 540 and thus into the locked position. If the recess 540 is not rotationally aligned with the locking arm 570 when the unlocking tool is withdrawn, the drive tool can be used to selectively rotate the shaft somewhat clockwise or counterclockwise (and thus slightly expand or contract the height H) until the recess 540 is aligned with the locking arm 570, at which point the locking arm 570 is urged into the recess 540 and into the locked position.

[0048] It should be understood that the above-described embodiments represent non-limiting examples of locking features for securing the implant at a desired height H. Additional non-limiting examples are described below with reference to Figures 6-17.

[0049] 6, in an additional embodiment, the at least one locking member can include a pair of pins 602 coupled to respective sliders 604 that extend into opposing locking channels 606 extending longitudinally along the proximal threaded portion 312 of the shaft 302. The pins 602 and sliders 604 are shown in a locked position with the shaft 302, in which the sliders 604 reside within the locking channels 606 and prevent rotation of the shaft 302. The pins 602 extend into guide slots 608 defined in the proximal wedge 304. The guide slots 608 are angled outwardly from the shaft 302 such that distal advancement of the slider 604 guides the pins 602 and slider 604 out of the locking channels 606, thereby allowing the shaft 302 to rotate.

[0050] 7A and 7B, the at least one locking member can be a flexible member, such as a clip spring 700, that can define one or more retention features 704 for gripping the shaft 302 in a manner that prevents shaft rotation about the axis X1. The clip spring 700 can include a pair of spring arms 702 that define the retention features 704 and bias the retention features against the shaft 302 along a direction substantially perpendicular to the axis X1, such as along a vertical direction V. The retention features 704 can be biased against a complementary surface, such as serrations 706 defined by the shaft 302. As shown in FIG. 7B, the clip spring 700 can reside within a receptacle 708 defined by the proximal wedge 304. The clip spring 700 can be unlocked by driving the spring arms 702 away from one another, such as via a tool 780 having protrusions 782 extending between the spring arms 702 and configured to push the arms 702 apart as the tool 780 is advanced distally. As the spring arms 702 move away from one another, the retaining arrangement 704 disengages from the serrations 706, allowing the shaft 302 to rotate.

[0051] 8, in an additional embodiment, the locking member can be a button 800, such as a push button or a sliding button. As shown, the button 800 can reside in a transverse receptacle 802 defined in the proximal wedge 304. The button 800 can define a bore 806, which may be eccentric, through which the shaft 302 extends. The button 800 can define a spring arm 804 that abuts a wall 808 of the receptacle 802 and biases the button 800 against the shaft 302 in a manner that prevents shaft rotation. To move the button 800 to an unlocked position, a tool can engage an end 810 of the button 800 opposite the spring arm 804 and slide the button 800 transversely to the unlocked position.

[0052] 9A and 9B, at least one locking member may be insertable into a receptacle of the shaft 302 to deform a portion of the shaft 302 radially outward relative to a respective portion of the proximal wedge 304, thereby preventing rotation of the shaft 302. For example, such a locking member may be a threaded pin 900 that may be inserted into a threaded receptacle 902, such as at the distal end of the socket 344. When the pin 900 is threaded into the receptacle 902, a head 904 of the pin 900 may press a flex tab 906 of the shaft 302 radially outward. As shown, the flex tab 906 may be defined by a U-shaped notch 908 in the body of the shaft 302.

[0053] In additional embodiments, the at least one locking member can comprise a ratchet locking assembly that can have a variety of configurations, non-limiting examples of such ratchet assemblies will now be described with reference to Figures 10A-13.

[0054] 10A-10C, the locking mechanism can include a ratchet locking assembly 1000 including a first plurality of ratchet teeth 1002 that engage with a second plurality of ratchet teeth 1004 as the implant expands. It should also be understood that each plurality of ratchet teeth can be referred to as a "set" of ratchet teeth. The first set of ratchet teeth 1002 can be defined along a component that advances proximate to another component as the implant 10 expands. For example, the first set of ratchet teeth 1002 can be arranged in a circular fashion along a flange 1006 of the shaft 302 and can be configured to rotate with the shaft 302 about a central axis X1. The second set of ratchet teeth 1004 can be arranged in a complementary circular pattern along the flexible ratchet support 1008, which can bias the first and second plurality of ratchet teeth 1002, 1004 into engagement with one another. The flexible ratchet support 1008 can also be configured to provide a measure of positional compliance between the first and second plurality of ratchet teeth 1002, 1004, such that the leading end faces of each of the ratchet teeth 1002, 1004 can slidingly engage one another, such as in a continuously interlocking manner.

[0055] As shown, the flexible ratchet support 1008 may include a support block 1008 that resides in a receptacle between the upper plate 100 and the lower plate 200. The support block 1008 may define a bore 1010 through which the shaft 302 extends. A spring member, such as a leaf spring 1012, may bias the support block 1008 toward the flange 1006, causing the first and second sets of ratchet teeth 1002 and ratchet teeth 1004 to engage with one another. It should be understood that one of the first and second sets of ratchet teeth 1002 and ratchet teeth 1004 need only include a single ratchet tooth for the ratchet assembly 1000 to provide a ratchet locking function for the implant 10. For example, the ratchet assembly 1000 can be configured such that as the implant 10 expands, at least one tooth of one set 1002, 1004 advances against at least one tooth of the other set 1004, 1002, and optionally against multiple teeth of the other set 1004, 1002, e.g., in a manner that continuously meshes along a first direction of movement. In some embodiments, one of the sets of ratchet teeth 1002, 1004 can be said to be configured to impede movement of at least one tooth of the other set in a second direction of movement opposite the first direction of movement.

[0056] It should be understood that in some embodiments, the set of ratchet teeth 1002, 1004 need not have a perfect locking geometry for the second direction of movement. In such embodiments, the set of ratchet teeth 1002, 1004 may simply provide an enhanced resistance or "drag" in the second direction of movement, which may be sufficient to prevent the implant 10 from losing height in some surgical applications.

[0057] 11 , in another embodiment, a ratchet lock assembly 1100 includes a first set of ratchet teeth 1102 that can be disposed along one or both sides 326, 328 of the proximal wedge 304 and / or distal wedge 304. As shown, the first set of ratchet teeth 1102 can be disposed along both sides 326, 328 of the proximal wedge 304. A second set of ratchet teeth 1104 can be disposed on one or more flexible support arms 1108, such as a pair of flexible support arms 1108, that can extend longitudinally from a block member 1110, such as a bearing member disposed vertically between the upper plate 100 and the lower plate 200.

[0058] 12, a ratchet locking mechanism 1200 can include a flexible ring member, e.g., a ring clip 1206 having flexible spring arms 1208 configured to ride along ratchet teeth 1202 in the form of radial protrusions defined along an outer surface of a shaft collar 1210 as the collar 1210 rotates with the shaft 302. Respective inner protrusions 1204 at the ends of the spring arms 1208 can function as pawls to allow the collar 1210 (and thus the shaft 302) to rotate about a first rotational direction to expand the implant 10, but to prevent or at least resist rotation of the shaft about the opposite rotational direction.

[0059] Now referring to FIG. 13 , at least one first ratchet tooth 1302 can be defined on an inner surface of a vertical guide extension 1306 of one of the plates 100, 200 (such as the upper plate 100), and the at least one first ratchet tooth 1302 can be configured to engage with a second set of ratchet teeth 1304 defined along an outer surface 1308 within a vertical guide channel 1310 defined by the other of the plates 200, 100 (such as the lower plate 200).

[0060] 14A-14C, in some embodiments, the at least one locking member can comprise a cam member 1402 that defines a cam surface 1404 and is rotatable about an axis during which the cam surface can move from a disengaged position to an engaged position. When in the engaged position, the cam surface 1404 can press against the shaft 302 or one of the wedges 304, such as the proximal wedge 304, in a manner that locks the relative position between the shaft 302 and the wedge 304. As shown by the dashed outline in FIG. 14A, the cam member 1402 can be an eccentric ring and / or washer that can have an inner surface configured to press against the shaft 302 as the ring / washer rotates to the locked position.

[0061] Alternatively, as shown in FIGS. 14B and 14C, the cam member 1402 may be a pin, and the pin may reside in a receptacle defined in one of the upper and lower plates 100 and 200 (such as the upper plate 100). The pin 1402 may be accessible, for example, after the implant 10 is expanded to a particular height. The distal end of the pin 1402 may define an eccentric nose 1404 that defines a cam surface. Once the implant is sufficiently expanded to expose or otherwise provide access to the pin 1402, the pin 1402 may be rotated to engage the eccentric nose 1404 with a complementary contact surface in a manner that prevents reduction of the expanded height H. It should be understood that various other cam locking structures are within the scope of the embodiments herein.

[0062] 15, in an additional embodiment, the at least one locking member can be a spring member, such as a leaf spring 1502, that can reside within a receptacle 1504 in the proximal wedge 304. The leaf spring 1502 can define a bore or channel 1506 through which the shaft 302 extends. The leaf spring 1502 can have a curved neutral profile, as shown. When in the neutral configuration, an inner surface 1508 of the leaf spring 1502 within the bore or channel 1506 can press against the shaft 302 in a locking manner. The leaf spring 1502 can be configured such that the inner surface 1508 disengages from the shaft 302 when it is forced into a straight or less curved configuration. It should be understood that the leaf spring 1502 and the receptacle can have other geometries for locking and disengaging from the shaft 302. For example, the leaf spring 1502 and receptacle 1504 may use an angled or featherboard-like locking configuration relative to the shaft 302 .

[0063] 16 , the proximal wedge 304 can define a slot 390 extending along the longitudinal direction L and configured to provide compliance to the proximal wedge along the transverse direction T. The slot 390 can be configured to bias side portions 392 of the proximal wedge 304 on either side of the slot 390 toward each other and against the shaft 302, for example, to inhibit shaft rotation. Alternatively, the slot 390 can be configured to bias the side portions away from each other and against one or both of the plates 100, 200, for example. The slotted proximal wedge 304 of this embodiment can be configured to allow a tool, for example an insertion tool, to engage a receptacle 394 in the wedge, thereby countering the biasing force, thereby disengaging the locking connection between the slotted wedge 304 and the shaft 302.

[0064] 17, in a further embodiment, the at least one locking member can comprise a ring member 1702, such as a snap ring, extending about a central axis X1 and around at least a portion of the shaft 302. The ring member 1702 can be configured to provide a sufficient degree of friction, resistance, or drag between the shaft 302 and the proximal wedge 304 to rotationally lock the shaft 302 relative to the proximal wedge 304 after the implant has expanded to the desired height H. Additionally or alternatively, a follower 1704, such as a ball-type or ring-type follower, can be present in a receptacle 1706 of one of the wedges, such as the proximal wedge 304, and can be configured to move along the external threads 306 in a manner that creates friction, resistance, or drag as the wedge 304 progresses along the shaft 302.

[0065] It should be appreciated that the implant embodiments described herein, in addition to fixing the relative positions between the various components in a manner that effectively locks the implants at their desired height H1, can further enhance structural support between the various components.

[0066] It should be appreciated that the various locking structures described herein for locking the implants at their desired height H1 (such as by fixing the relative position between the various implant components) can provide additional benefits and advantages. One such advantage is that such locking structures can further enhance structural support between the various components, such as reducing relative motion between selected components. Now referring to FIG. 18A, one such exemplary relative motion that can be advantageously reduced by embodiments herein is the angulation between the upper plate 100 and the lower plate 200 with respect to the horizontal plane LT, or in other words, the relative angulation about the vertical axis. Now referring to FIG. 18B, another such exemplary relative motion that can be advantageously reduced by embodiments herein is the angulation between the proximal and distal wedges 304 about the shaft axis X1. It should be appreciated that the aforementioned examples of relative motion are provided as non-limiting illustrative examples. Such types of relative motion can cause wear between the various components of the implant. Thus, by locking or otherwise fixing the relative positions between the components of the implant, undesirable relative motion can be significantly reduced, thereby providing an enhanced healing environment for the patient.

[0067] Additional examples of such retaining structures and stabilizing or reinforcing features will now be described with reference to Figures 19A-23D.

[0068] 19A-19C, the implant 10 can have one or more locking structures configured to lock at least one wedge 304 to one or both of the endplates 100, 200. The implant 10 can be configured generally similar to the implants 10 described above. However, in this embodiment, the proximal wedge 304 can be a wedge assembly 305 that includes a primary wedge body 307 and one or more locking guide members 335, such as a pair of locking guide members 335 vertically spaced apart from one another. The locking guide members 335 can have respective guide extensions 333 that are configured to extend into and translate along respective guide slots 337 of the primary wedge body 307 that intersect the upper and lower push surfaces 330 of the primary wedge body 307.

[0069] The locking guide member 335 can also define a guide arrangement 334 that is configured to ride within and along complementary guide channels 336 in the upper and lower plates 100, 200. The guide arrangement 334 in this embodiment is configured to interface with the plates 100, 200. For example, the guide arrangement 334 can have a dovetail geometry that is complementary to the shape of the guide channel 336 in a manner similar to that described above with reference to Figures 2B and 2C. The interlocking geometry in this embodiment is configured such that proximal translation of the locking guide member 335 relative to the primary wedge body 307 effectively clamps the plates 100, 200 to the primary wedge body 305.

[0070] The proximal wedge assembly 305 includes a locking actuator 339, such as a locking nut 339, that can be configured to reside in a locking receptacle 341 of the main wedge body 307. The locking nut 339 can be disposed along the shaft 302 and can define external threads 345 configured to threadingly engage the internal threads 343 of the guide extension 333. In this manner, rotation of the locking nut 339 about a first rotational direction can translate the locking guide member 335 proximally a distance relative to the wedge body 307, thereby tightening the plates 100, 200 against the wedge body 307, effectively locking the implant 10 at the desired height H.

[0071] 20A-20C, another embodiment of an implant 10 is shown having one or more locking structures configured to lock at least one wedge 304 to one or both of the endplates 100, 200. The implant 10 may be configured generally similar to the implants 10 described above. In this embodiment, the proximal wedge 304 may be a wedge assembly 305 that includes a pair of side wedge pieces 315 opposed to one another along the transverse direction T. The wedge assembly 305 may include a locking nut 2050 having one or more cam surfaces 2052. As such, the locking nut 2050 may be referred to as a “cammed locking nut” 2050.

[0072] The lock nut 2050 preferably defines internal threads 2060 configured to threadingly engage the external threads 306 of the proximal threaded region 312 of the shaft 302. The lock nut 2050 of this embodiment is configured to carry a side wedge piece 315 along the shaft 302 to expand the implant 10 while the lock nut 2050 remains in a neutral or unlocked position. For example, the lock nut 2050 can define a pair of flanges 2053, 2055 and an annular receptacle 2057 located longitudinally between the flanges 2053, 2055. The annular receptacle 2057 can be configured to engage one or more complementary follower projections 2054 defined within respective receptacles 2056 of the side wedge pieces 315. In this manner, the follower projection 2054 may be longitudinally retained within the annular receptacle 2057 between the flanges 2053, 2055, thereby allowing the side wedge pieces 315 to translate along the shaft 302 as the shaft rotates.

[0073] After the implant 10 has expanded to a desired height H, the cammed locking nut 2050 can be rotated relative to the side wedge pieces 315 to a locked position. As shown, the cam surfaces 2052 of the locking nut 2050 can be configured to engage cam follower surfaces 2062 defined in the receptacles 2056 of the side wedge pieces 315 in a manner that drives the side wedge pieces 315 away from each other along the transverse direction T. In this manner, as the side wedge pieces 315 separate in the transverse direction, the guide arrangements 334 of the wedge pieces 315 can be tightened outwardly relative to the plates 100, 200, increasing the interlocking engagement between the guide arrangements 334 and the complementary guide channels 336 sufficiently to lock the plates 100, 200 to the wedge assembly 305. When the side wedge pieces 315 are separated laterally in this manner, friction between the cam surface 2052 and the mating cam follower surface 2062 is configured to prevent the locking nut 2050 from rotating backwards out of the locked position.

[0074] 21A-21C, another embodiment of an implant 10 is shown having one or more locking structures configured to lock at least one wedge 304 to one or both of the endplates 100, 200. The implant 10 may be configured generally similar to the implants 10 described above. In this embodiment, the proximal wedge 304 may be a wedge assembly 305 including a first or inner wedge 2105 and a second or outer wedge 2107 coupled together. The inner wedge 2105 and the outer wedge 2107 may be configured to translate together along the proximal threaded region 312 of the shaft 302 in the unlocked configuration to facilitate expansion of the implant 10. The inner wedge 2105 and the outer wedge 2107 may be further configured to facilitate transition to a locked configuration with the plates 100, 200. For example, a locking actuator, such as a locking nut 2150 residing in locking receptacles 2152, 2154 of the inner and outer wedges 2105, 2107, respectively, can be rotated to cause distal translation of the outer wedge 2107 relative to the inner wedge 2105 a distance sufficient to eliminate any clearance between the outer wedge 2107 and the plates 100, 200. The locking nut 2150 can define internal threads 2156 that threadingly engage the proximal threaded region 312 of the shaft 302 to actuate the lock of the outer wedge 2107.

[0075] 21C, the inner wedge 2105 can define a bore 308 having internal threads 310 that threadingly engage the proximal threaded region 312 of the shaft 302 in a manner similar to that described above with respect to other embodiments herein. The inner wedge 2105 can define one or more pushing features, such as opposing transverse protrusions 2120 that engage complementary pushing surfaces 2122 defined by the outer wedge 2107. During expansion, the transverse protrusions 2120 of the inner wedge 2105 push distally against the pushing surfaces 2122 of the outer wedge 2107 to advance the inner wedge 2105 and the outer wedge 2107 together distally along the proximal threaded region 312 of the shaft 302. Once the implant 10 has expanded to the desired height H, the locking nut 2150 can be rotated by a tool to advance the locking nut 2150 distally along the proximal threaded region 312 of the shaft 302 relative to the inner wedge 2105. The locking nut 2150 has a push feature, such as a push surface 2158 that engages a complementary push surface 2160 on the outer wedge 2107, causing the complementary push surfaces 2158, 2160 to advance the outer wedge 2107 together with the locking nut 2150 against the inner wedge 2105, thereby clamping the outer wedge 2107 distally against the plates 100, 200 in a locking manner.

[0076] 22A-22D, in another embodiment, the implant 10 has one or more locking structures including push pins 2202 that drive the lock pins 2204 into locking engagement with the plates 100, 200. For example, the proximal wedge 304 can house a pair of push pins 2202 that are in a neutral or unlocked position during expansion of the implant 10. The push pins 2202 can extend along a horizontal plane LT and can be angled outward at an oblique angle relative to the axis X1. When the implant 10 is expanded to a desired height H1, the push pins 2202 can be actuated and driven distally to impinge on the lock pins 2204, such as by advancing a lock nut 350 within a lock receptacle 352 of the proximal wedge 304. The lock nut 350 and lock receptacle 352 can be configured similarly to those described above with reference to FIGS. 2A-3B. The locking pins 2204 can extend along respective vertical planes (e.g., vertical longitudinal planes VL). Actuation of the push pin 2202 can drive the locking pin 2204 such that its distal end 2206 abuts the plates 100, 200. The distal end 2206 of the locking pin 2204 can define a guide protrusion that extends into a complementary guide slot 2208 recessed in the contact surface 332 of the plates 100, 200.

[0077] 23A-23D, in an additional embodiment, the expandable implant 2300 can include a single block-like wedge body 2304 operable to expand at least one of the upper plate 2380 and the lower plate 2390 relative to the other along the vertical direction V. As shown, the block-like wedge body 2304 can have a substantially rectangular profile in one or more of the horizontal LT plane and both vertical planes VT, VL, and up to each of them. For example, the wedge body 2304 can define opposite sides 2306, 2308 along the transverse direction T, the sides 2306, 2308 being substantially planar along the respective vertical-longitudinal planes VL. The wedge body 2304 can also define opposite upper and lower surfaces 2310, 2312 along the vertical direction V, the upper and lower surfaces 2310, 2312 being substantially planar along the respective horizontal planes LT. The wedge body 2304 can also define opposing end faces 2314, 2316 along the longitudinal direction L, which are substantially planar along respective vertical-transverse planes VT. A portion of the planar sides 2306, 2308 are configured to slide along complementary planar surfaces 2318 defined along the inner walls 2320 of the plates 2380, 2390. In this manner, the block-shaped wedge body 2304 significantly increases the contact length between the wedge body 2304 and the upper and lower plates 2380, 2390.

[0078] The wedge body 2304 defines one or more angled features, such as a plurality of angled rails extending outwardly from the sides 2306, 2308 along the transverse direction T. The angled rails are configured to run along and / or into complementary angled guide channels defined along the inner walls 2320 of the upper plate 2380 and the lower plate 2390. The angled rails can include a first plurality of rails 2330 that are angled at a first angle relative to the axis X1 and configured to run along associated first plurality of guide channels 2340 in the upper plate 2380 or the lower plate 2390. The angled rails can also include a second plurality of rails 2332 that are angled at a second angle relative to the axis X1 and configured to run along associated second plurality of guide channels 2342 in the other of the upper plate 2380 and the lower plate 2390. In this manner, when the wedge body 2304 is actuated longitudinally relative to the plates 2380, 2390, the first plurality of rails 2330 and associated first plurality of guide channels 2340 are configured to drive the associated plate 2380, 2390 vertically away from the wedge body 2304, and the second plurality of rails 2332 and associated second plurality of guide channels 2342 are configured to drive the other plate 2380, 2390 vertically away from the wedge body 2304 in the opposite vertical direction, thereby expanding the implant 2300.

[0079] It should be understood that the implant 2300 of this embodiment and its various aspects can be configured as more fully described in U.S. Pat. No. 10,799,366, issued on October 13, 2020 to Davis et al., the entire disclosure of which is incorporated herein by reference.

[0080] It should be further understood that when a numerical preposition (e.g., "first," "second," "third") is used herein in reference to an element, component, dimension, or feature thereof, such numerical preposition is used to distinguish that element, component, dimension, and / or feature from another such element, component, dimension, and / or feature, and is not limited to the particular numerical preposition used in that instance. For example, as a non-limiting example, a "first" wedge, feature, flange, or direction may also be referred to as a "second" wedge, feature, edge, or direction in a different context without departing from the scope of the present disclosure, so long as that element, component, dimension, and / or feature remains appropriately distinguished in the context in which the numerical preposition is used.

[0081] Although the present disclosure has been described in detail, it should be understood that various changes, substitutions, and alterations may be made herein without departing from the spirit and scope of the present invention as defined by the appended claims. Moreover, the scope of the present disclosure is not intended to be limited to the specific embodiments described herein. In particular, one or more of the features from the foregoing embodiments may be used in other embodiments herein. As one skilled in the art would readily appreciate from the process, any now existing or later developed machine, manufacture, composition of matter, means, method, or step that performs substantially the same function or achieves substantially the same result as the corresponding embodiment described herein may be utilized in accordance with the present disclosure.

[0082] [Embodiment] (1) An expandable intervertebral cage, comprising: an upper plate and a lower plate opposed to each other along a vertical direction; a distal wedge and a proximal wedge, respectively, disposed between the upper plate and the lower plate, the distal wedge and the proximal wedge positioned opposite one another along a longitudinal direction substantially perpendicular to the vertical direction, the distal wedge and the proximal wedge each defining an inclined surface configured to engage complementary inclined surfaces of the upper plate and the lower plate in a manner that increases a distance between the upper plate and the lower plate along the vertical direction; an actuator located between the upper plate and the lower plate, the actuator defining a central axis oriented along the longitudinal direction, the actuator coupled to the distal wedge and the proximal wedge such that rotation of the actuator about the central axis moves at least one of the proximal wedge and the distal wedge relative to the other of the proximal wedge and the distal wedge along the longitudinal direction in a manner that increases the distance; and at least one locking component insertable into a receptacle defined at least in part by the proximal wedge, the at least one locking component configured to transition from an unlocked configuration in which the actuator is rotatable about the central axis relative to the proximal wedge, to a locked configuration in which the actuator is substantially rotationally fixed relative to the proximal wedge. (2) The expandable intervertebral cage of embodiment 1, wherein the at least one locking component comprises a nut threadably engaged with at least one of an internal thread defined within the bore of the proximal wedge and an external thread defined by the actuator. (3) The expandable intervertebral cage of embodiment 2, wherein the proximal wedge defines a retaining surface configured to retain the nut within the receptacle while the actuator moves at least one of the proximal wedge and the distal wedge relative to the other in the manner that increases the distance. (4) The expandable intervertebral cage of embodiment 2, wherein the nut is configured to be inserted into the receptacle after the distance has increased. (5) The expandable intervertebral cage of embodiment 1, wherein the at least one locking component includes a collet having a flexible leg extending distally along the longitudinal direction, the proximal wedge defining a tapered surface within the receptacle, and the collet configured to advance within the receptacle to bring the flexible leg into contact with the tapered surface, thereby clamping the flexible leg inwardly against the actuator in the locked configuration.

[0083] (6) The expandable intervertebral cage of embodiment 1, wherein the actuator includes a flange defining a plurality of recesses spaced about a circumference of the flange, and the at least one locking component includes a plunger and a spring configured to bias at least a portion of the plunger into at least one of the plurality of recesses in a manner that prevents rotation of the actuator about the central axis. (7) The expandable intervertebral cage of embodiment 1, wherein the at least one locking member includes a flexible member defining a retention structure, the flexible member configured to bias the retention structure against a complementary retention structure of the actuator in a biasing direction that is substantially perpendicular to the central axis. (8) The expandable intervertebral cage of embodiment 1, wherein the at least one locking member defines a geometric shape configured to deform a portion of the actuator radially outward relative to a portion of the proximal wedge in a manner that prevents rotation of the actuator relative to the proximal wedge. (9) The expandable intervertebral cage of embodiment 1, wherein the at least one locking member includes a cam member defining a cam surface and rotatable about a second axis, the cam surface configured to move from a disengaged position to an engaged position as the cam member rotates about the second axis, and in the engaged position, the cam surface presses against the actuator in a manner that prevents rotation of the actuator about the central axis. (10) The expandable intervertebral cage of embodiment 1, wherein the at least one locking member includes a spring member that contacts the actuator in a manner that prevents rotation of the actuator about the central axis when the spring member is in a neutral configuration, the spring member being configured to bend in response to a reaction force, and wherein the actuator is rotatable about the central axis when the spring member is bent.

[0084] (11) the proximal wedge defines a slot extending along the longitudinal direction, the slot providing compliance to the proximal wedge along a transverse direction substantially perpendicular to the longitudinal direction and the vertical direction, the compliance biasing side portions of the proximal wedge on either side of the slot toward each other and against the actuator in a manner that resists rotation of the actuator about the central axis; An expandable intervertebral cage as described in embodiment 1, wherein the at least one locking member includes an instrument, the receptacle is an instrument receptacle configured to receive at least a portion of the instrument, and when the at least a portion of the instrument is received within the receptacle, the side portions of the proximal wedge are forced away from each other, thereby allowing the actuator to rotate around the central axis. (12) The expandable intervertebral cage of embodiment 1, wherein the at least one locking member includes a ring member extending about the central axis and around at least a portion of the actuator, the ring member configured to provide sufficient friction between the actuator and the proximal wedge to rotationally lock the actuator relative to the proximal wedge after the actuator moves the at least one of the proximal and distal wedges relative to the other in the manner that increases the distance. (13) An expandable intervertebral cage, comprising: an upper plate and a lower plate opposed to each other along a vertical direction; a distal wedge and a proximal wedge, respectively, disposed between the upper plate and the lower plate, the distal wedge and the proximal wedge positioned opposite one another along a longitudinal direction substantially perpendicular to the vertical direction, the distal wedge and the proximal wedge each defining an inclined surface configured to engage complementary inclined surfaces of the upper plate and the lower plate in a manner that increases a distance between the upper plate and the lower plate along the vertical direction; an actuator located between the upper plate and the lower plate, the actuator defining a central axis oriented along the longitudinal direction, the actuator coupled to the distal wedge and the proximal wedge such that rotation of the actuator about the central axis moves at least one of the proximal wedge and the distal wedge relative to the other of the proximal wedge and the distal wedge along the longitudinal direction in a manner that increases the distance; and at least one locking component carried by the proximal wedge configured to transition from an unlocked configuration in which the proximal wedge is translatable along the longitudinal direction relative to at least one of the upper and lower plates to a locked configuration in which the proximal wedge is substantially longitudinally fixed relative to the at least one of the upper and lower plates. (14) The proximal wedge comprises a main wedge body and at least one locking guide member coupled together with the main wedge body, a first portion of the at least one guide member extending into a complementary guide channel of the main wedge body, a second portion of the at least one guide member extending into a complementary guide channel of at least one of the upper plate and the lower plate, the second portion of the at least one guide member having an interlocking geometry with the complementary guide channel of at least one of the upper plate and the lower plate; The expandable intervertebral cage of embodiment 13, wherein the at least one locking component comprises a locking actuator configured to retract the second portion relative to the main wedge body in a manner that longitudinally secures the main wedge body to the at least one of the upper plate and the lower plate. (15) The proximal wedge comprises a pair of side wedge pieces connected together; The expandable intervertebral cage of embodiment 13, wherein the at least one locking component includes a cam member disposed along the actuator, the cam member defining a cam surface, the cam member rotatable relative to the actuator and relative to the side wedge pieces to engage the cam surface against complementary follower surfaces defined by the side wedge pieces, thereby driving the side wedge pieces away from each other along a transverse direction substantially perpendicular to the vertical direction and the longitudinal direction, and tightening a guide formation defined by the side wedge pieces against complementary structures of the at least one of the upper plate and the lower plate.

[0085] (16) The proximal wedge is an inner wedge body that engages the actuator; an outer wedge body driven by the inner wedge body; The expandable intervertebral cage of embodiment 13, wherein the at least one locking component comprises a locking actuator configured to translate one of the inner wedge body and the outer wedge body along the longitudinal direction relative to the other of the inner wedge body and the outer wedge body, thereby longitudinally fixing the one of the inner wedge body and the outer wedge body relative to the at least one of the upper plate and the lower plate. (17) The expandable intervertebral cage of embodiment 13, wherein the at least one locking component comprises a plurality of push pins and a plurality of locking pins, the proximal wedge further carries a locking actuator configured to drive the plurality of push pins into engagement with the plurality of locking pins, and the locking pin responsively advances to contact the upper and lower plates in a manner that longitudinally secures the proximal wedge to both the upper and lower plates. (18) A longitudinally elongated expandable intervertebral cage, comprising: an upper plate and a lower plate opposed to each other along a vertical direction; a unitary wedge body having first and second sides opposed to one another along a transverse direction substantially perpendicular to the vertical direction, the first and second sides being substantially planar from a proximal end of the wedge body to a distal end of the wedge body, the first and second sides being configured to interface with respective planar surfaces defined along inner walls of the upper and lower plates, the single wedge body defining a plurality of angled rails extending outwardly from the first and second sides along the transverse direction, the angled rails being oriented at respective oblique angles relative to a central axis of the cage that is oriented along the longitudinal direction, the angled rails being configured to ride along respective angled guide channels defined along the inner walls of the upper and lower plates in a manner that increases the distance between the upper and lower plates along the vertical direction; an actuator located between the upper plate and the lower plate and extending along the central axis, the actuator coupled to the wedge body such that rotation of the actuator about the central axis moves the wedge body along the longitudinal direction in a manner that increases the distance. (19) The plurality of angle rails are a first plurality of rails inclined at a first angle relative to the central axis and configured to travel along associated first plurality of the guide channels defined in the upper plate; 19. The expandable intervertebral cage of claim 18, further comprising: a second plurality of rails inclined at a second angle relative to the central axis and configured to run along associated second plurality of guide channels defined in the lower plate. (20) The expandable intervertebral cage of embodiment 19, wherein the first plurality of angled rails extend outwardly from both the first side and the second side.

[0086] (21) The expandable intervertebral cage of embodiment 20, wherein the second plurality of angled rails extend outwardly from both the first side and the second side. (22) The expandable intervertebral cage of embodiment 18, wherein the unitary wedge body defines upper and lower surfaces that are substantially planar from the proximal end of the wedge body to the distal end of the wedge body. (23) An expandable intervertebral cage, comprising: an upper plate and a lower plate opposed to each other along a vertical direction; a distal wedge and a proximal wedge, respectively, disposed between the upper plate and the lower plate, the distal wedge and the proximal wedge positioned opposite one another along a longitudinal direction substantially perpendicular to the vertical direction, the distal wedge and the proximal wedge each defining an inclined surface configured to engage complementary inclined surfaces of the upper plate and the lower plate in a manner that increases a distance between the upper plate and the lower plate along the vertical direction; an actuator located between the upper plate and the lower plate, the actuator defining a central axis oriented along the longitudinal direction, the actuator coupled to the distal wedge and the proximal wedge such that rotation of the actuator about the central axis moves at least one of the proximal wedge and the distal wedge relative to the other of the proximal wedge and the distal wedge along the longitudinal direction in a manner that increases the distance; and a locking mechanism configured to maintain the increased distance, the locking mechanism including a ratchet assembly, the ratchet assembly comprising: a first plurality of ratchet teeth defined along the flexible ratchet support; a second plurality of ratchet teeth, wherein at least one tooth of the first plurality of ratchet teeth is configured to advance relative to the second plurality of ratchet teeth in a continuously meshing manner in a first direction of movement as the distance increases, and wherein the second plurality of ratchet teeth is configured to impede movement of the at least one tooth in a second direction of movement opposite the first direction of movement. (24) The expandable intervertebral cage of embodiment 23, wherein the flexible ratchet support is a block member disposed between the distal wedge and the proximal wedge, the block member defining a bore through which the actuator extends, the first plurality of ratchet teeth being arranged consecutively in a circular pattern on the block member, the second plurality of ratchet teeth being carried by a flange of the actuator and arranged in a circular pattern complementary to the circular pattern on the block member, and the block member being biased against the flange. (25) The expandable intervertebral cage of embodiment 23, wherein the flexible ratchet support extends longitudinally from a block member disposed vertically between the upper plate and the lower plate, and the second plurality of ratchet teeth are defined along a side of one of the proximal wedge and the distal wedge.

[0087] (26) The expandable intervertebral cage of embodiment 23, wherein the first plurality of ratchet teeth are defined along an outer periphery of a collar disposed along the actuator, and the flexible ratchet support is a ring clip extending from the proximal wedge, the ring clip having at least one flexible arm defining at least one ratchet tooth configured to engage with the first plurality of ratchet teeth. (27) The expandable intervertebral cage of embodiment 23, wherein the flexible ratchet support is a vertical extension of the upper plate that is receivable within a vertical guide channel of the lower plate, the first plurality of ratchet teeth being disposed along an inner surface of the vertical extension, and the second plurality of ratchet teeth being disposed along an outer surface within the vertical guide channel.

Claims

1. 1. An expandable intervertebral cage, comprising: an upper plate and a lower plate opposed to each other along a vertical direction; a distal wedge and a proximal wedge, respectively, disposed between the upper plate and the lower plate, the distal wedge and the proximal wedge positioned opposite one another along a longitudinal direction substantially perpendicular to the vertical direction, the distal wedge and the proximal wedge each defining an inclined surface configured to engage complementary inclined surfaces of the upper plate and the lower plate in a manner that increases a distance between the upper plate and the lower plate along the vertical direction; an actuator located between the upper plate and the lower plate, the actuator defining a central axis oriented along the longitudinal direction, the actuator coupled to the distal wedge and the proximal wedge such that rotation of the actuator about the central axis moves at least one of the proximal wedge and the distal wedge relative to the other of the proximal wedge and the distal wedge along the longitudinal direction in a manner that increases the distance; and at least one locking component insertable into a receptacle defined at least in part by the proximal wedge, the at least one locking component configured to transition from an unlocked configuration in which the actuator is rotatable about the central axis relative to the proximal wedge, to a locked configuration in which the actuator is substantially rotationally fixed relative to the proximal wedge.

2. 2. The expandable intervertebral cage of claim 1, wherein the at least one locking component comprises a nut threadingly engaged with at least one of an internal thread defined in a bore of the proximal wedge and an external thread defined by the actuator.

3. 3. The expandable intervertebral cage of claim 2, wherein the proximal wedge defines a retention surface configured to retain the nut within the receptacle while the actuator moves the at least one of the proximal wedge and the distal wedge relative to the other in the manner that increases the distance.

4. The expandable intervertebral cage of claim 2 , wherein the nut is configured to be inserted into the receptacle after the distance has increased.

5. 2. The expandable intervertebral cage of claim 1, wherein the at least one locking component includes a collet having flexible legs extending distally along the longitudinal direction, the proximal wedge defining a tapered surface within the receptacle, the collet configured for advancement within the receptacle to bring the flexible legs into contact with the tapered surface, thereby clamping the flexible legs inwardly against the actuator in the locked configuration.

6. 2. The expandable intervertebral cage of claim 1, wherein the actuator includes a flange defining a plurality of recesses spaced about a circumference of the flange, and the at least one locking component comprises a plunger and a spring configured to bias at least a portion of the plunger into at least one of the plurality of recesses in a manner that prevents rotation of the actuator about the central axis.

7. 2. The expandable intervertebral cage of claim 1, wherein the at least one locking member includes a flexible member defining a retention feature, the flexible member configured to bias the retention feature against a complementary retention structure of the actuator in a biasing direction that is substantially perpendicular to the central axis.

8. 2. The expandable intervertebral cage of claim 1, wherein the at least one locking member defines a geometric shape configured to deform a portion of the actuator radially outward relative to a portion of the proximal wedge in a manner that prevents rotation of the actuator relative to the proximal wedge.

9. 2. The expandable intervertebral cage of claim 1, wherein the at least one locking member includes a cam member defining a cam surface rotatable about a second axis, the cam surface configured to move from a disengaged position to an engaged position as the cam member rotates about the second axis, and in the engaged position, the cam surface presses against the actuator in a manner that prevents rotation of the actuator about the central axis.

10. 2. The expandable intervertebral cage of claim 1, wherein the at least one locking member includes a spring member that contacts the actuator in a manner that prevents rotation of the actuator about the central axis when the spring member is in a neutral configuration, the spring member configured to bend in response to a reaction force, and when the spring member is bent, the actuator is rotatable about the central axis.

11. the proximal wedge defines a slot extending along the longitudinal direction, the slot providing compliance to the proximal wedge along a transverse direction substantially perpendicular to the longitudinal direction and the vertical direction, the compliance biasing side portions of the proximal wedge on either side of the slot toward each other and against the actuator in a manner that resists rotation of the actuator about the central axis; 2. The expandable intervertebral cage of claim 1, wherein the at least one locking member includes an instrument, the receptacle is an instrument receptacle configured to receive at least a portion of the instrument, and when the at least a portion of the instrument is received within the receptacle, the side portions of the proximal wedges are forced away from each other, thereby allowing the actuator to rotate about the central axis.

12. 2. The expandable intervertebral cage of claim 1, wherein the at least one locking member includes a ring member extending about the central axis and around at least a portion of the actuator, the ring member configured to provide sufficient friction between the actuator and the proximal wedge to rotationally lock the actuator relative to the proximal wedge after the actuator moves the at least one of the proximal and distal wedges relative to the other in the manner that increases the distance.

13. 1. An expandable intervertebral cage, comprising: an upper plate and a lower plate opposed to each other along a vertical direction; a distal wedge and a proximal wedge, respectively, disposed between the upper plate and the lower plate, the distal wedge and the proximal wedge positioned opposite one another along a longitudinal direction substantially perpendicular to the vertical direction, the distal wedge and the proximal wedge each defining an inclined surface configured to engage complementary inclined surfaces of the upper plate and the lower plate in a manner that increases a distance between the upper plate and the lower plate along the vertical direction; an actuator located between the upper plate and the lower plate, the actuator defining a central axis oriented along the longitudinal direction, the actuator coupled to the distal wedge and the proximal wedge such that rotation of the actuator about the central axis moves at least one of the proximal wedge and the distal wedge relative to the other of the proximal wedge and the distal wedge along the longitudinal direction in a manner that increases the distance; and at least one locking component carried by the proximal wedge configured to transition from an unlocked configuration in which the proximal wedge is translatable along the longitudinal direction relative to at least one of the upper and lower plates to a locked configuration in which the proximal wedge is substantially longitudinally fixed relative to the at least one of the upper and lower plates.

14. the proximal wedge comprises a main wedge body and at least one locking guide member coupled together with the main wedge body, a first portion of the at least one guide member extending into a complementary guide channel of the main wedge body and a second portion of the at least one guide member extending into a complementary guide channel of at least one of the upper plate and the lower plate, the second portion of the at least one guide member having an interlocking geometry with the complementary guide channel of at least one of the upper plate and the lower plate; 14. The expandable intervertebral cage of claim 13, wherein the at least one locking component comprises a locking actuator configured to retract the second portion relative to the primary wedge body in a manner to longitudinally secure the primary wedge body to the at least one of the upper plate and the lower plate.

15. the proximal wedge comprises a pair of side wedge pieces joined together; 14. The expandable intervertebral cage of claim 13, wherein the at least one locking component includes a cam member disposed along the actuator, the cam member defining a cam surface, the cam member rotatable relative to the actuator and relative to the side wedge pieces to engage the cam surface against complementary follower surfaces defined by the side wedge pieces, thereby driving the side wedge pieces away from one another along a transverse direction substantially perpendicular to the vertical and longitudinal directions and clamping a guide arrangement defined by the side wedge pieces against complementary structure of the at least one of the upper and lower plates.

16. The proximal wedge is an inner wedge body that engages the actuator; an outer wedge body driven by the inner wedge body; 14. The expandable intervertebral cage of claim 13, wherein the at least one locking component comprises a locking actuator configured to translate one of the inner and outer wedge bodies along the longitudinal direction relative to the other of the inner and outer wedge bodies, thereby longitudinally securing the one of the inner and outer wedge bodies relative to the at least one of the upper and lower plates.

17. 14. The expandable intervertebral cage of claim 13, wherein the at least one locking component comprises a plurality of push pins and a plurality of locking pins, the proximal wedge further carrying a locking actuator configured to drive the plurality of push pins into engagement with the plurality of locking pins, the locking pin responsively advancing to contact the upper and lower plates in a manner that longitudinally secures the proximal wedge to both the upper and lower plates.

18. 1. A longitudinally elongated expandable intervertebral cage, comprising: an upper plate and a lower plate opposed to each other along a vertical direction; a unitary wedge body having first and second sides opposed to one another along a transverse direction substantially perpendicular to the vertical direction, the first and second sides being substantially planar from a proximal end of the wedge body to a distal end of the wedge body, the first and second sides being configured to interface with respective planar surfaces defined along inner walls of each of the upper and lower plates; the single wedge body defining a plurality of angled rails extending outwardly from the first and second sides along the transverse direction, the angled rails being oriented at respective oblique angles relative to a central axis of the cage that is oriented along the longitudinal direction, the angled rails being configured to ride along respective angled guide channels defined along the inner walls of the upper and lower plates in a manner that increases the distance between the upper and lower plates along the vertical direction; an actuator located between the upper plate and the lower plate and extending along the central axis, the actuator coupled to the wedge body such that rotation of the actuator about the central axis moves the wedge body along the longitudinal direction in a manner that increases the distance.

19. The plurality of angle rails are a first plurality of rails inclined at a first angle relative to the central axis and configured to travel along associated first plurality of the guide channels defined in the upper plate; 20. The expandable intervertebral cage of claim 18, including a second plurality of rails inclined at a second angle relative to the central axis, the second plurality of rails configured to travel along associated second plurality of guide channels defined in the inferior plate.

20. 20. The expandable intervertebral cage of claim 19, wherein the first plurality of angled rails extend outwardly from both the first side and the second side.

21. 21. The expandable intervertebral cage of claim 20, wherein the second plurality of angled rails extend outwardly from both the first side and the second side.

22. 20. The expandable intervertebral cage of claim 18, wherein the unitary wedge body defines upper and lower surfaces that are substantially planar from the proximal end of the wedge body to the distal end of the wedge body.

23. 1. An expandable intervertebral cage, comprising: an upper plate and a lower plate opposed to each other along a vertical direction; a distal wedge and a proximal wedge, respectively, disposed between the upper plate and the lower plate, the distal wedge and the proximal wedge positioned opposite one another along a longitudinal direction substantially perpendicular to the vertical direction, the distal wedge and the proximal wedge each defining an inclined surface configured to engage complementary inclined surfaces of the upper plate and the lower plate in a manner that increases a distance between the upper plate and the lower plate along the vertical direction; an actuator located between the upper plate and the lower plate, the actuator defining a central axis oriented along the longitudinal direction, the actuator coupled to the distal wedge and the proximal wedge such that rotation of the actuator about the central axis moves at least one of the proximal wedge and the distal wedge relative to the other of the proximal wedge and the distal wedge along the longitudinal direction in a manner that increases the distance; and a locking mechanism configured to maintain the increased distance, the locking mechanism including a ratchet assembly, the ratchet assembly comprising: a first plurality of ratchet teeth defined along the flexible ratchet support; a second plurality of ratchet teeth, wherein at least one tooth of the first plurality of ratchet teeth is configured to advance relative to the second plurality of ratchet teeth in a continuously intermeshing manner in a first direction of movement as the distance increases, the second plurality of ratchet teeth configured to impede movement of the at least one tooth in a second direction of movement opposite the first direction of movement.

24. 24. The expandable intervertebral cage of claim 23, wherein the flexible ratchet support is a block member disposed between the distal wedge and the proximal wedge, the block member defining a bore through which the actuator extends, the first plurality of ratchet teeth being arranged consecutively in a circular pattern on the block member, and the second plurality of ratchet teeth being carried by a flange of the actuator and arranged in a circular pattern complementary to the circular pattern on the block member, the block member being biased against the flange.

25. 24. The expandable intervertebral cage of claim 23, wherein the flexible ratchet support extends longitudinally from a block member disposed vertically between the upper and lower plates, and the second plurality of ratchet teeth are defined along a side of one of the proximal and distal wedges.

26. 24. The expandable intervertebral cage of claim 23, wherein the first plurality of ratchet teeth are defined along a circumference of a collar disposed along the actuator, and the flexible ratchet support is a ring clip extending from the proximal wedge, the ring clip having at least one flexible arm defining at least one ratchet tooth configured to engage the first plurality of ratchet teeth.

27. 24. The expandable intervertebral cage of claim 23, wherein the flexible ratchet support is a vertical extension of the upper plate receivable within a vertical guide channel of the lower plate, the first plurality of ratchet teeth being disposed along an inner surface of the vertical extension and the second plurality of ratchet teeth being disposed along an outer surface within the vertical guide channel.

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