Expandable lordotic interbody implants and related methods

Abstract

The present disclosure relates to an expandable interbody implant, the expandable interbody implant comprising upper and lower shells surrounding a control mechanism having interlocking proximal and distal cages and an adjustment screw that translates the distal cage longitudinally relative to the proximal cage, thereby pushing apart the distal ends of the upper and lower shells to deploy the interbody implant.

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to expandable implants, such as spinal interbody and intervertebral body devices, and more particularly to spinal interbody implants that are expandable after placement in the spinal column. [Background technology]

[0002] Fusion cages and other types of interbody implants and devices are often used in spinal surgery within the vertebrae or in the disc space between each vertebra (interbody). With an interbody device, one or more such vertebral bodies are placed between the adjacent vertebrae to support and promote fusion. Such fusion may be necessary due to disease, injury, general deterioration, or a congenital problem. Summary of the Invention [Problem to be solved by the invention]

[0003] A goal of most spinal surgeries is to minimize the trauma of the surgery itself. One way to minimize trauma is to create the smallest possible access port to reach the surgical site, which limits the size of tools and implants that can pass through the access port.

[0004] However, some interbody devices are now made expandable. Expandable interbody implants are initially smaller than conventional non-expandable (static) interbody implants so that the expandable interbody implant can be more easily inserted and / or implanted into the disc space. Once placed in the disc space, the expandable interbody implant is expanded to a desired size to achieve the amount of expansion needed for a particular patient. [Means for solving the problem]

[0005] The present disclosure relates to an expandable lordotic interbody implant that can be inserted into an intervertebral disc space in a collapsed state to minimize patient trauma and then expanded to achieve a desired lordosis. The interbody implant includes upper and lower shells surrounding a control mechanism. The upper and lower shells can each have at least one implantation window, which in some embodiments are aligned with one another. The control mechanism includes interlocking proximal and distal cages and an adjustment screw that translates the distal cage longitudinally relative to the proximal cage. Translation of the distal cage pushes apart the distal ends of the upper and lower shells, deploying the interbody implant.

[0006] According to one embodiment, one or both of the upper and lower shells have angled slots in their side walls that extend distally toward a central plane that bisects the interbody implant into upper and lower halves. Interlocking proximal and distal cages contained within the upper and lower shells are configured for longitudinal translation relative to one another by adjustment screws that threadably engage the proximal or distal cages.

[0007] In some embodiments, the adjustment screw threadably engages a distally disposed threaded hole in the distal cage, while the proximal end of the adjustment screw is secured to the proximal cage such that it is longitudinally fixed relative to the proximal cage, which can optionally be accomplished using a pin inserted into the distal end of the proximal cage, the pin configured to engage a radial groove or flange on the adjustment screw.

[0008] In some embodiments, the adjustment screw is configured to threadably engage a distally disposed threaded hole in the distal cage, while the distal end of the adjustment screw contacts and, in some embodiments, applies pressure to the inner surface of the distal end of the distal cage. At least a portion of the distal end of the adjustment screw may be tapered or rounded to reduce friction between the adjustment screw and the distal cage. In some embodiments, one or more rods are configured to fit or be secured to the distal cage (as described in more detail below) to longitudinally secure the adjustment screw relative to the distal cage. In such embodiments, the distal end of the adjustment screw has a radial groove or flange for engaging the rod. In some embodiments, one or more ends of the rod may function as lateral protrusions that slide along angled slots. In some embodiments, the rods may be integral to the distal cage.

[0009] Whether threadably engaged with the proximal or distal cage, rotation of the adjustment screw translates the distal cage longitudinally, forcing the distal end of the distal cage against the inner surfaces of the upper and lower shells. Alternatively or additionally, lateral protrusions of the distal cage slide along slots in the side walls of the upper and lower shells, forcing the upper and lower shells apart. Because the proximal ends of both the upper and lower shells rotate to engage the proximal end of the proximal cage, the expansion force exerted by the distal cage on the upper and lower shells causes the upper and lower shells to open in a clamshell-like manner to achieve lordosis when inserted between two vertebrae of the spinal column.

[0010] In some embodiments, the distal end of the distal cage has a beveled, tapered, rounded, and / or angled surface. In some embodiments, a rod, which may have a coefficient of friction lower than that of the material of the distal cage, is inserted or secured to a distal portion of the distal cage such that it is the primary or only point of contact between the inner surfaces of the upper and lower shells and the distal cage.

[0011] In some embodiments, the expandable interbody implant has one or more retention protrusions configured to unfold or expand from the interbody implant upon deployment. The retention protrusions may be sharp and embedded in the upper and lower vertebrae, or may at least resist movement of the interbody implant. In some embodiments, the proximal ends of the retention protrusions are secured to or form an integral part of a rod that is fitted to or rotatably secured to the distal cage. Translation of the distal cage forces the retention protrusions out of respective holes or windows in the upper and lower shells, which may be located distally.

[0012] According to some embodiments, the edges of the upper and lower shells are configured to abut one another to completely or at least partially enclose the control assembly when the interbody implant is in a collapsed state. In some embodiments, the edge of one shell has a protrusion and the edge of the other shell has a corresponding recess configured to receive the protrusion and thereby provide additional rigidity to the interbody implant in the collapsed state. In some embodiments, the upper and lower shells at least partially nest within one another when in the collapsed state. In some embodiments, the side walls of the proximal and distal cages are sized and configured to abut the inner surfaces of the upper and lower shells to provide stability or rigidity in the deployed state as well as the collapsed state.

[0013] According to some embodiments, the expandable interbody implant includes one or more metals, such as steel, cobalt, cobalt-chromium, titanium, or alloys thereof. In some embodiments, the interbody implant further includes one or more polymers, such as polyether ether ketone (PEEK). In some embodiments, at least a portion of the interbody implant includes a porous material, such as a porous metal (e.g., one or more layers of porous titanium).

[0014] Further disclosed herein are embodiments of an insert for use with an expandable interbody implant. The insert can include: (1) a handle portion including an extension portion having a cannula extending from a proximal end of the handle portion to a distal end of the extension portion; (2) an engagement portion at the distal end of the extension portion having an engagement mechanism for engaging the expandable interbody implant and one or more counter-torque extensions for preventing rotation of the interbody implant; and (3) a deployment tool extending from the proximal end of the cannula to the distal end of the cannula for insertion into the expandable interbody implant to engage and actuate the adjustment screw.

[0015] Some embodiments of the insert include a deployment indicator, which may be located on the handle or extension. The deployment indicator visually indicates to the user the degree to which the interbody implant is deployed in place. In some embodiments, the interbody implant can be "pre-deployed," meaning that in the collapsed state, the upper and lower shells are at least partially deployed to achieve greater deployment when in the deployed state. In such embodiments, different deployment tools, each corresponding to a different degree of pre-deployment, may be used to cooperate with the deployment indicator to accurately indicate the degree of deployment.

[0016] Further disclosed herein are methods for implanting and deploying an expandable interbody implant. Such methods include (1) using an insert to position the interbody implant, which may be in a collapsed or pre-deployed state, into the disc space; (2) deploying the interbody implant by rotating a control knob on the insert to deploy the interbody implant; and (3) releasing or removing the deployed interbody implant from the insert. In some embodiments, the method further includes the step of injecting or inserting bone growth material into the interbody implant, which may be performed by the insert or using a separate device. In embodiments in which an insert is used, a portion of the insert is removed to allow the insert to inject or insert bone growth material into the interbody implant. [Brief explanation of the drawings]

[0017] The present embodiments illustrated in the drawings are exemplary and exemplary in nature and are not intended to limit the subject matter defined by the claims. The following detailed description of exemplary embodiments can be better understood when read in conjunction with the following drawings, in which like structure is designated with like reference numerals and in which:

[0018] [Figure 1] FIG. 1 is a perspective front view of an embodiment of an expandable interbody implant in a collapsed or undeployed state. [Figure 2] FIG. 2 is a perspective rear view of the embodiment of FIG. 1 in an undeployed state. [Figure 3] FIG. 2 is a side view of the embodiment of FIG. 1 in a deployed state. [Figure 4] FIG. 2 is an exploded rear view showing the embodiment of FIG. 1. [Figure 5A] FIG. 2 is a top view of the expandable interbody implant of FIG. 1 in an undeployed state. [Figure 5B] 5B is a side cross-sectional view of the expandable interbody implant of FIG. 1 in an undeployed state taken along line DD shown in FIG. 5A. [Figure 6A]FIG. 2 is a top view showing the expandable interbody implant of FIG. 1 in a deployed state. [Figure 6B] 6B is a side cross-sectional view of the expandable interbody implant of FIG. 1 in a deployed state taken along line DD shown in FIG. 6A. [Figure 7] 2 is a perspective view showing an insert engaged with the expandable interbody implant of FIG. 1. FIG. [Figure 8] 8 is a perspective view showing the distal portion of the insert of FIG. 7 removed from the expandable interbody implant of FIG. 1. [Figure 9] FIG. 10 is a perspective front view of another embodiment of an expandable interbody implant in a collapsed or undeployed state. [Figure 10] FIG. 10 is a perspective front view showing the embodiment of FIG. 9 in a deployed state. [Figure 11] FIG. 10 is an exploded front view of the embodiment of FIG. 9. [Figure 12] FIG. 10 is an exploded front view of another embodiment of an expandable interbody implant. [Figure 13] FIG. 10 is an exploded front view of another embodiment of an expandable interbody implant. DETAILED DESCRIPTION OF THE INVENTION

[0019] The present disclosure relates to deployable and / or dynamic interbody implants (between adjacent vertebrae), intervertebral bodies (within vertebrae), and / or spinal stabilization devices that may be used as interbody fusion cages or devices, interbody stabilization devices, etc. (hereinafter collectively referred to as spinal device(s)) for support, stabilization, and / or promotion of bone growth between or within vertebrae that have become unstable or damaged due to injury or disease. In particular, the present disclosure provides various versions of dynamic (deployable and / or deployable and retractable) interbody devices that can be used in the human spine to achieve or promote proper lordosis.

[0020] FIG. 1 illustrates an exemplary dynamic spinal interbody device, or deployable or interbody implant 10. FIG. 1 illustrates a perspective front view of the interbody implant 10 in an undeployed or folded state. The interbody implant 10 includes an upper shell 15 and a lower shell 20. The upper surface of the upper shell 15 is configured to contact and support the lower surface of a first vertebral body. Similarly, the lower surface of the lower shell 20 is configured to contact and be supported by the upper surface of a second vertebral body. In the illustrated embodiment, the upper shell 15 and the lower shell 20 include projections or teeth 22 configured to resist or minimize movement of the interbody implant 10 after placement in the intervertebral space between the first and second vertebrae. In some embodiments, the upper shell 15 and the lower shell 20 additionally or alternatively include roughened surfaces, which may be achieved by coatings and / or surface treatments. The first and second vertebrae may represent, for example, L1-L2, L2-L3, L3-L4, L4-L5, or L5-S1 of the human spinal column, although the interbody implant 10 may alternatively be used in the thoracic or cervical spine.

[0021] Both upper shell 15 and lower shell 20 are configured to hinge at their respective proximal ends at upper hinge point 25 and lower hinge point 30. The distal ends of each of upper shell 15 and lower shell 20 are shown as tapered or having a bullet-nose shape. While a tapered distal end can aid in inserting interbody implant 10 into the disc space, in some embodiments, the distal end of interbody implant 10 is not tapered at all. In some embodiments, such a tapered portion can comprise a relatively straight but angled surface, and in some embodiments, such a tapered portion can include one or more curves.

[0022] FIG. 1 shows that the edges of upper shell 15 and lower shell 20 abut one another in an unexpanded state to form a closed shell. Both upper shell 15 and lower shell 20 can be seen to have horizontal surfaces and respective side walls. FIG. 1 shows that one side wall of upper shell 15 has an angled slot 35. In this illustrated embodiment, a similar slot is provided in the opposite side wall of lower shell 20 on the side of interbody implant 10, which is not shown in FIG. 1. These angled slots extend entirely through upper shell 15 and lower shell 20; however, in some embodiments, the slots do not extend completely through the shells, but instead have channels or recesses formed in the interior surfaces of the shells.

[0023] Although not shown, in some embodiments, the edges of the side walls may have protrusions and corresponding holes or slots for receiving the protrusions. For example, the lower surface of the side wall of upper shell 15 may have one or more protrusions that are received by corresponding holes in the upper surface of the side wall of lower shell 20 when in the undeployed state. Such a configuration may increase the structural integrity or stability of interbody implant 10 in the undeployed state and may be particularly useful when interbody implant 10 is inserted into an intervertebral space and may be subjected to compressive forces for precise placement.

[0024] FIG. 1 further shows that upper shell 15 has implantation windows 40. Similar implantation windows are provided in lower shell 20. These implantation windows allow bone ingrowth through interbody implant 10 after implantation. These implantation windows further allow bone growth-inducing or promoting materials to be inserted or forced into interbody implant 10, at least partially exit interbody implant 10, and potentially contact and interact with the bone surfaces of the upper and lower vertebral bodies. In some embodiments, interbody implant 10 has only one implantation window or no implantation windows. In some embodiments, interbody implant 10 has three or more implantation windows, which may be located in locations other than those shown in FIG. 1. In some embodiments, as described in more detail below, interbody implant 10 is capable of achieving new bone ingrowth instead of or in addition to through-growth.

[0025] FIG. 2 is a perspective rear view of interbody implant 10. This perspective rear view shows that interbody implant 10 includes a proximal cage 50, which will be described in more detail below. FIGS. 1 and 2 illustrate that upper hinge point 25 and lower hinge point 30 have a pair of transverse processes on proximal cage 50 that engage with proximal hooks on upper shell 15 and lower shell 20, respectively. This configuration allows upper shell 15 and lower shell 20 to rotate at their respective proximal ends. In some embodiments, this movement can be achieved using a pin extending through proximal cage 50 as a rotation point. However, the use of the transverse processes and hooks shown in the drawings not only reduces the number of parts, but also allows for a larger internal threaded hole 110 than would be possible if one or more pins were used at upper hinge point 25 and / or lower hinge point 30.

[0026] Figure 2 shows that the proximal cage 50 has a threaded hole 110 at its proximal end that is configured to threadably receive an insert, such as that shown in Figure 8. In certain embodiments, the insert engages the interbody implant 10 with any number of other suitable engagement means, such as an insert tube having a lug that is inserted into a similar key-shaped hole that allows passage of the insert tube through the proximal cage and then partially rotates to secure one or more protruding lugs to the inner wall.

[0027] FIG. 3 shows interbody implant 10 in an expanded state. In the expanded state, the distal ends of upper shell 15 and lower shell 20 are spaced apart while their respective proximal ends rotate about upper hinge point 25 and lower hinge point 30. In this expanded state and in the perspective view of FIG. 3, interbody implant 10 can be seen to include distal cage 45, proximal cage 50, and adjustment screw 55. These elements are sometimes referred to herein as a control assembly. Proximal cage 50 and distal cage 45 are configured to interlock with one another, as shown in more detail in FIG. 4, to permit relative movement or translation of proximal cage 50 and distal cage 45 along a longitudinal axis, which is the longitudinal axis of adjustment screw 55, which extends through an opening in proximal cage 50 and threadably engages with a threaded hole in the distal end of distal cage 45.

[0028] In the illustrated embodiment, rotation of adjustment screw 55 to translate distal cage 45 relative to proximal cage 50 deploys interbody implant 10 from an undeployed state to an deployed state. Additionally, because upper hinge point 25 and lower hinge point 30 are located at the proximal end of proximal cage 50, longitudinal translation of distal cage 45 applies force to one or more interior surfaces of upper shell 15 and lower shell 20, causing the distal ends of upper shell 15 and lower shell 20 to open in a clamshell-like fashion.

[0029] According to certain embodiments, the distal end of the proximal cage 50 includes a threaded hole that threadably engages with the adjustment screw 55. In such embodiments, the distal cage 45 does not include a threaded hole, but is configured to receive a force applied by the distal end of the adjustment screw 55 as the adjustment screw 55 advances through the proximal cage 50. The force applied to the distal cage 45 by the adjustment screw 55 causes the distal cage 45 to translate longitudinally relative to the proximal cage 50, thereby separating the distal ends of the upper and lower shells 15 and 20. By threadably engaging the adjustment screw 55 with the distal end of the proximal cage 50, certain embodiments can reduce the amount of friction between the adjustment screw 55 and the interbody implant 10, such that less force is required to rotate the adjustment screw 55. Additionally, tapering the distal end of the adjustment screw 55 can, in certain embodiments, further reduce friction between the adjustment screw 55 and the interbody implant 10.

[0030] In the embodiment shown in FIG. 3, the distal cage 45 has a tapered distal end. In some embodiments, the tapered distal end has a uniformly angled surface 60. In some embodiments, a rounded or cylindrical surface is provided near the distal end of the distal cage 45, either in addition to or instead of the angled surface 60. In the embodiment shown in FIG. 3, the cylindrical surface has a pin or rod 65 that is positioned in a notch in the upper surface of the distal cage 45. A corresponding pin or rod may be positioned in a notch in the lower surface of the distal cage 45, although in some embodiments, only one rod is used. In some embodiments, the rod or rods are integral with the distal cage 45. In some embodiments, the rounded or cylindrical surface is provided with a material that has a lower coefficient of friction than the coefficient of friction of the material forming the angled surface 60 or the remainder of the distal cage 45.

[0031] 1-4 show that the distal cage 45 has a lateral protrusion 70 configured to slide into the angled slot 35. Comparing the deployed state of FIG. 3 with the undeployed state of FIGS. 1 and 2, it can be seen that the lateral protrusion 70 has moved from the proximal end of the angled slot 35 to the distal end. The distal cage 45 has a second lateral protrusion on the opposite side of the distal cage 45, the side not shown in FIG. 2. The second lateral protrusion, similar to the lateral protrusion 70, is configured to slide into an angled slot in the sidewall of the lower shell 20. The exact angle of the angled slot 35 in the upper shell 15 (and the corresponding angled slot 85 in the lower shell 20) can be selected to achieve a desired lordosis angle and / or a desired rate of deployment per rotation of the adjustment screw 55. In one embodiment, the angle of the angled slot 35 is different from the angle of the angled slot 85 in the lower shell 20 so that rotating the adjustment screw 55 to expand the interbody implant 10 results in uneven expansion on each side of the interbody implant 10.

[0032] According to certain embodiments, one or both of rods 65 and / or rods 80 function as corresponding lateral protrusions on the opposite side of lateral protrusion 70 and / or distal cage 45. For example, rods 65 and / or rods 80 need only extend beyond the illustrated rods so as to extend into the side walls of upper shell 15 and / or lower shell 20. Such a configuration can reduce the number of parts, which can affect the cost of interbody implant 10 as well as manufacturability and structural integrity.

[0033] In some embodiments, one or both of the upper shell 15 and the lower shell 20 include a porous material, which can be a metal, a polymer, or a combination of the two. In some embodiments, one or both of the upper shell 15 and the lower shell 20 have notches or recesses in one or more outer surfaces and contain a layer of porous material configured to occupy the notches or recesses in the one or more outer surfaces. In some embodiments, the layer of porous material is simply attached or secured to the upper and / or lower surfaces of the interbody implant 10, eliminating the use or need for notches. In some embodiments, the porous material is one or more layers of a porous sheet, such as one or more layers of a porous titanium sheet. The one or more layers of porous titanium can be diffusion bonded to one or more outer surfaces of the upper shell 15 and / or the lower shell 20. In some embodiments, the porous material surrounds one or both of the implantation windows, is adjacent to one or both of the implantation windows, or replaces one or both of the implantation windows. In some embodiments, the porous material is disposed on one or more sidewalls in addition to or instead of the upper or lower surfaces of the interbody implant 10 .

[0034] FIG. 4 is an exploded view of the embodiment of FIG. 1 , further visualizing certain aspects of the various components of the interbody implant 10. For example, slot 85 in the sidewall of lower shell 20 and the interlocking structures of proximal cage 50 and distal cage 45 can be seen. Also shown in FIG. 4 is angled surface 75 on lower shell 20. In this illustrated embodiment, both lower shell 20 and upper shell 15 have angled surfaces that slope toward the distal ends of the shells. As explained above, the expandable interbody implant 10 deploys when adjustment screw 55 longitudinally moves distal cage 45 away from or toward proximal cage 50. This movement of distal cage 45 causes the distal portion of distal cage 45 to press against at least one of upper shell 15 and lower shell 20. In some embodiments, the tapered end or angled surface 60 of distal cage 45 (and optionally a corresponding angled surface on the underside of distal cage 45) slides against one or both of the angled surfaces of upper shell 15 and lower shell 20. In some embodiments, the same movement is achieved by rod 65 and / or rod 80 sliding against one or both of the angled surfaces of upper shell 15 and lower shell 20. In some embodiments, longitudinal movement of distal cage 45 causes lateral protrusion 70 to slide along slot 35 (and optionally a corresponding lateral protrusion on the opposite side of distal cage 45 to slide along slot 85 in one side wall of lower shell 20), thereby moving the distal ends of upper shell 15 and lower shell 20 apart.

[0035] In one embodiment, the mechanism by which the expandable interbody implant 10 deploys is a combination of all three structural relationships (the tapered end of the distal cage 45, the rods 65 and 80, and the lateral protrusion 70), a combination of two of these structural relationships, or one of these structural relationships.

[0036] FIG. 3 shows that the adjusting screw 55, in this embodiment, has a threaded portion 90, a head 95, and a flange 100 disposed between the head 95 and the threaded portion 90. When assembled, the adjusting screw 55 extends through an opening in the distal portion of the proximal cage 50, and the threaded portion 90 threadably engages with a threaded hole in the distal cage 45. The longitudinal position of the adjusting screw 55 is fixed relative to the proximal cage by a pin 105. In this illustrated embodiment, the pin 105 fits into a slot in the distal portion of the proximal cage 50. The pin 105 has a protrusion or extension that engages with the flange 100 of the adjusting screw 55 to maintain the adjusting screw 55 in a fixed longitudinal orientation relative to the proximal cage 50. In some embodiments, the flange 100 is a groove or recess configured to receive the pin 105. In some embodiments, the flange 100 is associated with the groove or recess. In one embodiment, the pin 105 has a cylindrical shape and engages the adjustment screw 55 along only one side of the adjustment screw 55 .

[0037] The components shown in FIG. 4 can be formed of any suitable material, such as one or more metals or one or more polymers. Such materials include titanium, steel, cobalt, gold, platinum, silver, iridium, tantalum, tungsten, alloys thereof, polyvinylidene fluoride, polyethylene, polypropylene, polydimethylsiloxane, parylene, polyamide, polytetrafluoroethylene, polymethylmethacrylate, polyimide, PEEK, and polyurethane. In some embodiments, one or more of the components shown in FIG. 4 include a porous material. The porous material may include a porous metal, a porous polymer, or a mixture of the two. For example, in some embodiments, one or more components include or are fabricated from porous titanium. In some embodiments, the porous titanium includes layered sheets of porous titanium diffusion-bonded together to form a single unit. In some embodiments, one or more of the upper shell 15, the lower shell 20, the distal cage 45, and the proximal cage 50 are fabricated from or include layered sheets of porous titanium diffusion-bonded together. The use of such porous components allows bone growth through and into the interbody implant 10 itself, rather than simply through the implantation window.

[0038] An inserter (see FIG. 7) suitable for use with the expandable interbody implant 10 has engagement means (see FIG. 8) for engaging the proximal portion of the proximal cage 50, and the inserter has an adjustment tool portion extending through the screw hole 110 to engage the head 95 of the adjustment screw 55 to expand or collapse the interbody implant 10 by rotating the adjustment screw 55.

[0039] 5B and 6B are cross-sectional views of the expandable interbody implant 10 in both the undeployed ( FIG. 5B ) and deployed ( FIG. 6B ) states. These figures illustrate the function of the adjustment screw 55 and how the distal cage 45 interacts with the upper and lower shells 15, 20 to force the distal ends of the two shells apart, moving the interbody implant 10 from the undeployed state to the deployed state.

[0040] Figures 5 and 6 further show how the implantation window 40 in the upper shell 15 has a corresponding implantation window in the lower shell 20, and further show that the two implantation windows, together with the openings in the respective structures of the distal cage 45 and the proximal cage 50 (see Figure 4), form openings throughout the entire depth of the interbody implant 10 to allow bone penetration growth.

[0041] 5 illustrates that the upper and lower shells 15, 20 of the interbody implant 10 define distinct, substantially parallel surfaces when the interbody implant 10 is in an undeployed state. In the undeployed state, the upper and lower surfaces of the upper and lower shells 15, 20 may be substantially parallel or may have a slight angle, such as, for example, about 0.5°, about 1°, about 1.5°, about 2°, within a range of about 0° to about 1°, within a range of about 0.2° to about 1.2°, or within a range of about 0.5° to about 2°. In certain embodiments, the angle between the respective upper and lower surfaces may be less than about 5°, less than about 4°, less than about 3°, or less than about 2°. According to certain embodiments, an initial or pre-deployment angle between the respective upper and lower surfaces greater than 0° may facilitate a larger angle in the deployed state.

[0042] According to some embodiments, the initial angle is achieved by the configuration of the upper shell 15 and the lower shell 20 rather than or in conjunction with a pre-deployed interbody implant 10. In some embodiments, the upper shell 15 and / or the lower shell 20 are thickened toward their respective distal ends. By configuring the upper shell 15 and / or the lower shell 20 in this manner, an initial angle between the upper shell 15 and the lower shell 20 of about 1° to about 15°, including any angle, can be achieved. In some embodiments, the resulting initial angle is at least about 1°, at least about 3°, at least about 5°, at least about 7°, at least about 9°, at least about 11°, at least about 13°, less than about 14°, less than about 12°, less than about 10°, less than about 8°, less than about 6°, and / or less than about 4°.

[0043] In one embodiment, the internal components of interbody implant 10 are identical for embodiments with and without an initial angle. In other words, an embodiment without an initial angle can achieve a deployment angle of approximately 20°, while the same internal components used in an embodiment with a thicker shell having an initial angle of approximately 10° can achieve a deployment angle of approximately 30°.

[0044] The length of interbody implant 10, defined as the distance between the proximal-most and distal-most portions of upper shell 15 (or lower shell 20), can be any suitable value. In some embodiments, the length is within the range of about 14 mm to about 41 mm, including all values ​​between about 14 mm and about 41 mm. In some embodiments, the length of interbody implant 10 is about 20 mm, about 22.5 mm, about 25 mm, about 27.5 mm, about 30 mm, about 32.5 mm, at least about 20 mm, at least about 25 mm, at least about 30 mm, at least about 35 mm, less than about 40 mm, less than about 37 mm, less than about 33 mm, less than about 27 mm, in the range of about 15 mm to about 25 mm, in the range of about 20 mm to about 30 mm, or in the range of about 25 mm to about 35 mm.

[0045] The width of interbody implant 10, defined as the distance between the outer edges of each sidewall of upper shell 15 (or lower shell 20), can be any suitable value. In some embodiments, the width value is selected to provide maximum stability to the upper and lower vertebrae. In some embodiments, the width is within the range of about 7 mm to about 27 mm, including all values ​​between about 7 mm and about 27 mm. In certain embodiments, this value is about 8 mm, about 10 mm, about 12 mm, about 14 mm, about 16 mm, about 18 mm, about 20 mm, about 22 mm, about 24 mm, about 26 mm, at least about 7.5 mm, at least about 12.5 mm, at least about 17.5 mm, at least about 22.5 mm, less than about 27 mm, less than about 23 mm, less than about 19 mm, less than about 15 mm, in the range of about 7 mm to about 13 mm, in the range of about 9 mm to about 15 mm, in the range of about 11 mm to about 17 mm, in the range of about 13 mm to about 19 mm, in the range of about 15 mm to about 21 mm, in the range of about 17 mm to about 23 mm, or in the range of about 19 mm to about 25 mm.

[0046] 6 shows that the angle between the respective planes defined by the upper and lower shells 15, 20 in the deployed state can be within the range of about 4° to about 40°, including any value between about 4° and about 40°. In certain embodiments, the angle is about 10°, about 15°, about 20°, about 25°, about 30°, or about 35°. In some embodiments, the angle in the deployed state is at least about 5°, at least about 10°, at least about 15°, at least about 20°, at least about 25°, at least about 30°, in the range of about 5° to about 10°, in the range of about 7.5° to about 12.5°, in the range of about 10° to about 15°, in the range of about 12.5° to about 17.5°, in the range of about 15° to about 20°, in the range of about 17.5° to about 22.5°, in the range of about 20° to about 25°, in the range of about 22.5° to about 27.5°, in the range of about 25° to about 30°, or in the range of about 27.5° to about 32.5°.

[0047] FIG. 7 illustrates an inserter 115 for use with the interbody implant 10. The inserter 115 has a distal end configured to engage the proximal end of the interbody implant 10 and a proximal end configured to be handled and manipulated by a user (e.g., a surgeon). The inserter 115 includes a deployment tool 120 including a handle 125 and a rod (not shown). The rod extends through a lumen extending the length of the inserter 115 and at least partially beyond the distal end of the inserter 115 so as to extend at least partially into the interbody implant 10 when the inserter 115 engages the interbody implant 10. The distal end of the rod of the deployment tool 120 is configured to engage with the head 95 of the adjustment screw 55. Thus, rotation of the handle 125 rotates the rod of the deployment tool 120, which in turn rotates the adjustment screw 55 to deploy or collapse the interbody implant 10.

[0048] The distal end of the inserter 115 has a threaded engagement portion 150 (see FIG. 8 ) and a lateral extension portion 130. The engagement portion 150 is configured to engage with the threaded hole 110 of the proximal cage 50. The lateral extension portion 130 provides a counter torque to the rotation applied by the engagement portion 150 to hold the interbody implant 10 in place while the engagement portion 150 rotates to engage or disengage the inserter 115 from the interbody implant 10. Manipulation of the engagement portion 150 is accomplished by rotating an engagement knob 135 located toward the proximal end of the inserter 115.

[0049] 8 shows that engagement portion 150 is hollow, allowing deployment tool 120 to extend through engagement portion 150 into interbody implant 10 and through the proximal portion of proximal cage 50 to engage the adjustment screw. Although not shown, deployment tool 120 can be removed from insert body 115 so that a biologic or bone growth promoting material can be injected through insert body 115 and into interbody implant 10.

[0050] Furthermore, in some embodiments, particularly when interbody implant 10 is in an undeployed state, lateral extension 130 abuts the proximal edges of the side walls of upper shell 15 and lower shell 20. This configuration allows inserter 115 to distribute the insertion or compression force to the shell portions, rather than having proximal cage 50 bear the entire insertion force.

[0051] The proximal portion of the inserter 115 has a surface that facilitates use of the inserter 115 for inserting, withdrawing, deploying, or collapsing the interbody implant 10. In the embodiment shown in FIG. 7, the proximal portion of the inserter 115 has a flat surface that is easy for the surgeon to grasp. The proximal portion may also have a deployment indicator 140 that indicates the amount or degree of deployment of the interbody implant 10. The deployment indicator 140 can be particularly useful to the surgeon because deployment may not be visible when the interbody implant 10 is inserted into the intervertebral space. Furthermore, fluoroscopic images likely do not provide the surgeon with accurate information regarding the deployment angle achieved at that location. The deployment indicator 140 may also provide a percentage value for deployment. For example, if the interbody implant 10 is configured to achieve a 20° angle when fully deployed, the deployment indicator 140 indicates the percentage of that angle achieved. When the interbody implant 10 is in an undeployed state (before insertion), the deployment indicator 140 indicates a 0% deployment rate. When the interbody implant 10 is deployed to approximately 10°, the deployment indicator 140 indicates 50% deployment, and when the interbody implant 10 is deployed to approximately 20°, the deployment indicator 140 indicates 100% deployment. In one embodiment, the deployment indicator 140 is configured to provide the actual degree or angle of deployment.

[0052] According to certain embodiments, the undeployed state of the interbody implant 10 is defined as a configuration in which the angle between the superior and inferior surfaces is greater than 0°. Such a configuration can advantageously allow for a greater degree of deployment or angle of deployment in the final deployed state. In certain embodiments, the initial angle is within a range of about 0.5° to about 10°, including all angles between about 0.5° and about 10°. In certain embodiments, the initial angle is about 1°, about 1.5°, about 2°, about 2.5°, about 3°, about 3.5°, about 4°, about 4.5°, greater than about 1°, greater than about 3°, less than about 9°, less than about 7°, within a range of about 0.5° to about 3.5°, within a range of about 2.5° to about 5.5°, within a range of about 4.5° to about 7.5°, or within a range of about 6.5° to about 9.5°.

[0053] As previously mentioned, rotation of the deployment tool 120 not only deploys the interbody implant 10, but in some embodiments also affects the deployment indicators 140 to indicate to the surgeon the degree or percentage of deployment achieved by the interbody implant 10 at that position. In some embodiments where the interbody implant 10 is initially pre-deployed (e.g., the minimum angle is greater than 0°), the deployment tool 120 communicates with the deployment indicators 140 to indicate such pre-deployment. For example, a different deployment tool 120 may be provided for each degree or percentage of pre-deployment. In other words, if the interbody implant 10 is provided with a 1° pre-deployment and a 5° pre-deployment, one particular deployment tool 120 will be used when the insert 115 is coupled to the interbody implant at the 1° pre-deployment, as communicated to the deployment indicators 140 by the deployment tool 120. If the interbody implant is used with the 5° pre-deployment, a different deployment tool 120 will be used. For example, if the interbody implant 10 is initially pre-deployed to 5° and can achieve a 25° deployment state, the deployment tool 120 is configured so that the deployment indicator 140 indicates an initial deployment percentage of 20%. Thus, when the surgeon inserts the interbody implant 10, the deployment indicator 140 alerts the surgeon that the interbody implant 10 is pre-deployed or has an initial degree of deployment greater than 0°. However, in some embodiments, such pre-deployment is not indicated by the deployment indicator 140.

[0054] The insert 115 shown in Figure 7 has a notch facing its proximal end. This notch (and any corresponding notch on the underside of the insert 115) is configured to engage a counter-torque device (not shown). Such a device can be used to hold the insert 115 in place and prevent twisting of the insert 115 when the handle 125 of the deployment tool 120 is rotated to deploy the interbody implant 10.

[0055] The interbody implant 10 may be surgically implanted in a patient using any number of suitable methods. In one embodiment, a method for implanting the interbody implant 10 includes the initial step of engaging the distal end of the inserter 115 with the proximal end of the proximal cage 50 by contacting the distal tip of the inserter 115 with the proximal end of the proximal cage 50 and rotating the engagement knob 135, and then rotating the engagement portion 150 to engage the threads of the engagement portion 150 with the threads of the threaded hole 110 in the proximal cage 50. The engagement knob 135 is rotated until the lateral extension portion 130 is fully advanced into the respective slots in the proximal end of the proximal cage 50 and the proximal end of the sidewalls of the upper and lower shells 15 and 20, respectively, of the proximal end of the interbody implant 10. Once the insert 115 is engaged with the interbody implant 10, a deployment tool 120 can be inserted through the insert 115 to engage the distal end of the deployment tool with the adjustment screw 55. In one embodiment, the deployment tool 120 is already in place within the insert 115 before the insert 115 engages the interbody implant 10.

[0056] The interbody implant 10 is then positioned within the disc space and positioned as desired. Positioning of the interbody implant 10 in the desired location can be performed using fluoroscopy. To this end, one or more components of the interbody implant 10 can be at least partially radiopaque. In some embodiments, the interbody implant 10 includes one or more radiopaque markers, the primary purpose of which is to aid in proper positioning of the interbody implant 10 within the disc space. In some embodiments, the deployment tool 120 is not inserted through the inserter 115 until the interbody implant 10 is properly positioned within the disc space. In embodiments in which the interbody implant 10 is positioned prior to insertion of the deployment tool 120, the proximal end of the inserter 115 can be configured to withstand hammer blows that may be required to properly position the interbody implant 10.

[0057] With the interbody implant 10 properly positioned, the deployment tool 120, which may need to be inserted through the inserter 115 at this stage, is rotated to rotate the adjustment screw 55, thereby longitudinally moving the distal cage 45 relative to the proximal cage 50. Moving the distal cage 45 away from the proximal cage 50 applies outward pressure to the upper and lower shells 15 and 20. In some embodiments, this outward pressure comes from the lateral projections 70 (and corresponding lateral projections on the opposite side of the distal cage 45) sliding along the angled slots 35 and 85, respectively. In some embodiments, this outward pressure comes from the tapered distal end of the distal cage 45 pressing against the beveled interior surfaces of the upper and lower shells 15 and 20. In some embodiments, this outward pressure comes from the rods 65, 80 pressing against the beveled interior surfaces of the upper and lower shells 15, 20. In some embodiments, this outward pressure results from a combination of two or more of these structural interactions.

[0058] The interbody implant 10 is deployed by continuing to rotate the deployment tool 120 until the desired amount of deployment is reached, which may be monitored using a deployment indicator 140, which indicates the amount of deployment by degree, rate, or any other suitable method.

[0059] Once the desired amount of deployment is achieved, the deployment tool 120 is removed from the insert 115. In some embodiments, a biologic or bone growth promoting material is then injected into the interbody implant 10 by injecting the biologic or bone growth promoting material through the cannula structure of the insert 115. In some embodiments, such material is injected into the interbody implant 10 or the space surrounding the interbody implant 10 after the insert is removed from the interbody implant 10. The insert is removed from the interbody implant by turning the engagement knob 135 until the distal tip of the insert 115 can be freely withdrawn from the surgical space without affecting the placement of the interbody implant 10.

[0060] FIG. 9 illustrates an alternative embodiment of an expandable interbody implant 210 comprising an upper shell 215 and a lower shell 220. Many aspects of the interbody implant 210 are similar to those of the interbody implant 10 (including the upper hinge point 225, the lower hinge point 230, the proximal cage 250, the lateral projection 270, the angled slot 235, the dentition 222, and the implantation window 240), but the upper shell 215 and the lower shell 220 have openings on their upper and lower surfaces, respectively, toward the distal end of the interbody implant 210. While only the upper opening 212 is shown in the perspective view shown in FIG. 9, in this embodiment, a corresponding opening is provided in the lower shell 220. In some embodiments, only one shell has such an opening.

[0061] FIG. 10 shows that when interbody implant 210 is deployed (by angled ramps 260 pressing against the inner surfaces of upper shell 215 and lower shell 220, and / or by lateral protrusions 270 sliding along angled slots 235 and lateral protrusions (not shown) sliding along angled slots 285, and / or by rods 265, 280 sliding along the inner ramp surfaces of upper shell 215 and lower shell 220), the distal ends of upper shell 215 and lower shell 220 not only clamshell apart to engage the upper and lower vertebral bodies, but also that retention protrusions extend through openings formed in upper shell 215 and lower shell 220 to prevent, limit, or reduce movement or migration of interbody implant 210 within the intervertebral space. Similar to interbody implant 10, interbody implant 210 includes upper and lower rods 265 and 280; however, in this embodiment, upper rod 265 serves as the connection and hinge point for upper retention prong 214, which extends through upper opening 212 when interbody implant 210 is deployed. Correspondingly, lower rod 280 serves as the connection and hinge point for lower retention prong 216, which extends through lower opening 212. In some embodiments, only one expandable retention prong is provided. In some embodiments, the retention prong is integral with the rod. In some embodiments, the retention prong is free to rotate about the rod. Distal longitudinal translation of distal cage 245 forces upper and lower retention prongs 214 and 216 against and slide along their respective openings to deploy or expand from interbody implant 210. Conversely, proximal translation of distal cage 245 retracts upper and lower retention prongs 214 and 216 back into interbody implant 210 .

[0062] 11 is an exploded view of interbody implant 210 that may show how upper and lower retention prongs 214, 216 are coupled to upper and lower rods 265, 280, respectively. In some embodiments, the two components may be fused, bonded, bonded, or glued together, or may be constructed of a single piece.

[0063] 11 further shows that the distal end of the proximal cage 250 has a threaded hole 224. In this embodiment, the distal cage 245 does not have a threaded hole. This means that the adjusting screw 255 threadably engages the threaded hole 224, and when rotated, longitudinally moving the adjusting screw 255 distally forces the distal end of the adjusting screw 255 (which is shown as smooth or rounded, although the distal end of the adjusting screw 255 may be tapered to reduce friction on some or all of the distal surface of the tip) against the distal end of the distal cage 245, thereby moving the distal cage 245 so that it pushes apart the distal ends of the upper and lower shells 215, 220. In some embodiments, the distal end of the adjusting screw 255 is held in place within the distal end of the distal cage 245 using a pin that allows the adjusting screw 255 to rotate freely. In one embodiment, the distal end of the adjustment screw 255 is configured to snap-fit ​​into engagement with the distal cage 245 .

[0064] In some embodiments, a resistance element (not shown) may be incorporated into the proximal cage 250, preferably at its distal end. Such a resistance element may have a threaded interior through which the adjustment screw 255 threads. However, unlike the threaded holes 224 of the proximal cage 250, the resistance element is configured to apply at least some resistance to rotation of the adjustment screw 255. Such resistance may prevent the deployable interbody implant 210 from accidentally collapsing and reducing its volume during and / or after the surgical procedure. The resistance element may comprise any number of suitable materials, such as a metal (e.g., steel, titanium, alloys thereof, etc.) or a polymer (e.g., polyvinylidene fluoride, polyethylene, polypropylene, polydimethylsiloxane, parylene, polyamide, polytetrafluoroethylene, polymethylmethacrylate, silicone, polyimide, PEEK, polyurethane, or a combination thereof). In some embodiments, the resistance element is threaded inward, and in some embodiments, the resistance element is not threaded inward and simply applies a frictional force to the adjustment screw 255 .

[0065] 12 illustrates an alternative embodiment of expandable interbody implant 310 that differs significantly from expandable interbody implant 210 in the configuration of adjustment screw 355 and how adjustment screw 355 interacts with proximal cage 350 and distal cage 345. Other aspects of expandable interbody implant 310 largely mirror those of expandable interbody implant 210, including upper shell 315, lower shell 320, upper hinge point 325, lower hinge point 330, proximal cage 350, lateral projection 370, angled slot 335, angled slot 385, teeth 322, and upper opening 312. Also provided within interbody implant 310 are upper retention protrusions 314 and lower retention protrusions 316. Similar to interbody implant 210, the rotation point for upper retention prong 314 is upper rod 365 and the rotation point for lower retention prong 316 is lower rod 380; however, in interbody implant 310, both upper rod 365 and lower rod 380 are configured to engage the distal end of adjusting screw 355, which in one embodiment has a flange or groove toward the distal end of adjusting screw 355 to accommodate upper rod 365 and lower rod 380. Such engagement with adjusting screw 355 can cause adjusting screw 355 to retract distal cage 345 to collapse or at least partially collapse interbody implant 310. This configuration can reduce the number of components required to achieve the desired deployment and retraction of interbody implant 310.

[0066] 12 further illustrates that the distal end of the adjustment screw 355 has a partially tapered tip, which, in one embodiment, reduces the amount of friction between the distal end of the adjustment screw 355 and the distal cage 345.

[0067] 12 further shows a resistance element 333 having a threaded throughbore configured to receive an adjustment screw 355 and provide resistance to unintended or undesired rotation of the adjustment screw 355. The resistance element 333 is configured to be received by the proximal cage 350 and may comprise a different material than the proximal cage 350. For example, the resistance element 333 may comprise a polymer such as PEEK, as opposed to the proximal cage 350, which may comprise a metal such as titanium or a titanium alloy.

[0068] 13 illustrates an alternative embodiment of an expandable interbody implant 410 that differs from the expandable interbody implant 310 not only in that the interbody implant 410 lacks the upper and lower retention prongs 314, 316, but also primarily in the configuration of the adjustment screw 455, which in this illustrated embodiment is a twin screw having a first screw 455A and a second screw 455B. The first screw 455A has a threaded hole that threadably engages with the external threads of the second screw 455B. This configuration increases the amount of translation or movement of the distal cage 445 relative to the proximal cage 450. Rotating the first screw 455A, which threadably engages with the threaded hole 424 of the proximal cage 450, causes the first screw 455A to translate relative to the proximal cage 450. This rotation further translates the second screw 455B so that its distal end engages the distal cage 445 and is rotationally secured to the distal cage 445 by the cross pin 455C. The cross pin 455C is then secured to the distal cage 445 by crimping the edge 455D of the hole through which the cross pin is inserted during assembly.

[0069] According to one embodiment, the use of twin screws, as in this illustrated embodiment, reduces friction between the adjustment screw 455 and the distal cage 445, such that less torque is required to deploy the interbody implant 410. In one embodiment, a cross pin 455C to secure the second screw 455B to the distal cage 445 is not required and may simply be achieved by a friction fit with the distal end of the second screw 455B. However, the use of the cross pin 455C may facilitate closure of the interbody implant 410, such as when the interbody implant 410 needs to be repositioned or removed from the disc space.

[0070] As with other embodiments disclosed herein, interbody implant 410 includes upper rod 465 and lower rod 480. As with certain other embodiments, these rods are configured to slide into angled slots 435 and angled slots 485, respectively. This illustrated embodiment demonstrates that these rods may be configured to engage upper shell 415 and lower shell 420 solely through their respective angled slots.

[0071] As with certain other embodiments, the upper shell 415 and the lower shell 420 include implantation windows and projections, teeth, or anti-migration features 422. Additionally, each shell includes a hinge point at its proximal end that, in this embodiment, includes not only a curved surface but also a curved wall. Thus, although the upper hinge point 425 and the lower hinge point 430 each rotate about their respective proximal engagement features with the proximal cage 450, the additional curved wall may provide additional stability to the interbody implant 410 overall.

[0072] Embodiment The following embodiments are provided only as examples of particular configurations, materials, arrangements, etc., contemplated by the authors of this disclosure.

[0073] Embodiment 1. An upper shell having a proximal end and a distal end, defining an upper surface extending from the proximal end to the distal end and configured to engage an inferior surface of a first vertebral body, and further having a pair of side walls, at least one of the side walls having a first angled slot extending distally along the side wall in a direction away from the upper surface; a lower shell having a proximal end and a distal end, defining a lower surface extending from the proximal end to the distal end and configured to engage the superior surface of the second vertebral body, and further having a pair of side walls, at least one of the side walls having a second angled slot extending distally along the side wall in a direction away from the lower surface; a control assembly disposed between the upper and lower shells, the control assembly having interlocking proximal and distal cages and an adjustment screw defining a longitudinal axis, the proximal cage having a proximal bore and a distal bore, the distal cage having a proximal bore, the adjustment screw extending through the distal bore of the proximal cage; It is equipped with a proximal portion of the proximal cage having a pair of upper hinge points about which the upper shell rotates and a pair of lower hinge points about which the lower shell rotates; the distal cage having a first lateral protrusion configured to engage with the first angled slot and a second lateral protrusion configured to engage with the second angled slot; An expandable interbody implant in which rotation of the adjustment screw causes the distal cage to translate along the longitudinal axis, which in turn moves the distal ends of the upper and lower shells apart from an undeployed state to an expanded state.

[0074] Embodiment 2. The expandable interbody implant of embodiment 1, wherein the adjustment screws are twin screws having a proximal screw and a distal screw, the proximal screw having a screw hole that opens at its distal end, and the distal screw threadably engaging the screw hole.

[0075] Embodiment 3. The expandable interbody implant of embodiment 2, wherein the distal end of the distal screw engages the distal cage such that the distal screw is rotationally fixed relative to the distal cage.

[0076] Embodiment 4. The expandable interbody implant of embodiment 1, 2 or 3, wherein the distal hole of the proximal cage is threaded and the adjustment screw threadably engages with the threaded distal hole of the proximal cage.

[0077] Embodiment 5. The expandable interbody implant of embodiment 1, 2, 3 or 4, wherein the distal end of the adjustment screw is configured to abut the interior surface at the distal end of the distal cage.

[0078] Embodiment 6. The expandable interbody implant of embodiment 1, 2, 3, 4 or 5, wherein the distal cage further comprises a retaining pin configured to hold the adjustment screw in place longitudinally relative to the distal cage.

[0079] Embodiment 7. The expandable interbody implant of embodiment 1, 2, 3, 4, 5 or 6, wherein the distal end of the adjustment screw is at least partially tapered.

[0080] Embodiment 8. The expandable interbody implant of embodiment 1, wherein the distal cage further comprises a threaded distal hole, and the adjustment screw is threadably engaged with the threaded distal hole.

[0081] Embodiment 9. The expandable interbody implant of embodiment 8, wherein the proximal cage further comprises a retaining pin configured to hold the adjustment screw in a predetermined position longitudinally relative to the proximal cage.

[0082] Embodiment 10. The expandable interbody implant of embodiment 1, 2, 3, 4, 5, 6, 7, 8 or 9, wherein the distal cage further has a distal inclined surface configured to slidingly engage with the respective inclined surfaces of the upper shell and the lower shell.

[0083] Embodiment 11. The distal cage is formed by the upper and lower shells. Inside 11. The expandable interbody implant of embodiment 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, further comprising a rounded upper surface and a rounded lower surface, each configured for sliding engagement with the corresponding one of the vertebral bodies.

[0084] Embodiment 12. The expandable interbody implant of embodiment 11, wherein the rounded upper surface and the rounded lower surface are rods fixed to the distal cage.

[0085] Embodiment 13. The expandable interbody implant of embodiment 12, wherein the rod functions as both the first lateral projection and the second lateral projection of the distal cage.

[0086] Embodiment 14. The expandable interbody implant of embodiment 12 or 13, wherein the rod comprises a material having a coefficient of friction lower than the coefficient of friction of the material forming the distal cage.

[0087] Embodiment 15. The expandable interbody implant of embodiment 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 or 14, further comprising expandable upper and / or lower retention protrusions configured to expand when the expandable interbody implant transitions from an undeployed state to an expanded state.

[0088] Embodiment 16. The expandable interbody implant of embodiment 15, wherein the upper and / or lower retention protrusions are configured to retract when the expandable interbody implant transitions from a deployed state to a non-deployed state.

[0089] Embodiment 17. The upper shell has an upper opening on its upper surface toward the distal end thereof, the upper opening being configured to allow the expandable upper retention protrusion to pass through the upper opening when expanded; An expandable interbody implant of embodiment 15 or 16, wherein the lower shell has a lower opening on its lower surface toward the distal end of the lower shell, the lower opening being configured to allow the expandable lower retention protrusion to pass through the lower opening when expanded.

[0090] Embodiment 18. The expandable interbody implant of embodiment 15, 16 or 17, wherein the upper and / or lower retaining protrusions are rotatably coupled to the distal cage of the control assembly.

[0091] Embodiment 19. The expandable interbody implant of embodiment 18, wherein translation of the distal cage along the longitudinal axis causes the upper and / or lower retention prongs to expand or retract.

[0092] Embodiment 20. An expandable interbody implant of embodiment 15, 16, 17, 18 or 19, which refers to embodiment 12, 13 or 14, wherein the upper and / or lower retaining protrusions are attached to the respective rods of the distal cage.

[0093] Embodiment 21. An expandable interbody implant of embodiment 20, wherein the rod of the distal cage is configured to engage with the distal end of the adjusting screw having a radial recess for receiving at least a portion of the rod, and this engagement longitudinally fixes the distal cage relative to the adjusting screw.

[0094] Embodiment 22. An expandable interbody implant of embodiment 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or 21, wherein the upper hinge point and the lower hinge point have respective lateral protrusions configured to engage with the proximal portions of the upper and lower cages.

[0095] Embodiment 23. An expandable interbody implant of embodiment 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21 or 22, wherein in an undeployed state, the respective side walls of the upper and lower shells abut each other to enclose the control assembly.

[0096] Embodiment 24. An expandable interbody implant of embodiment 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22 or 23, wherein the distal ends of the upper and lower shells are curved to surround the distal end of the distal cage when the interbody implant is in an undeployed state.

[0097] Embodiment 25. An expandable interbody implant of embodiment 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 or 24, wherein the upper shell, the lower shell, the proximal cage and the distal cage each have at least one opening extending from the upper surface of the upper shell to the lower surface of the lower shell to define a channel for bone growth.

[0098] Embodiment 26. The expandable interbody implant of embodiment 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25, wherein the expandable interbody implant comprises a titanium alloy.

[0099] Embodiment 27. The expandable interbody implant of embodiment 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 or 26, further comprising a resistance element configured to resist rotation of the adjustment screw.

[0100] Embodiment 28. The expandable interbody implant of embodiment 27, wherein the resistance element comprises a polymer.

[0101] Embodiment 29. The expandable interbody implant of embodiment 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, or 28, wherein at least one of the upper shell, the lower shell, the proximal cage, the distal cage, and the adjustment screw comprises a porous material.

[0102] Embodiment 30. The expandable interbody implant of embodiment 29, wherein the porous material has two or more layers of porous sheets bonded together to form a homogenous material.

[0103] Embodiment 31. The expandable interbody implant of embodiment 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29 or 30, wherein the upper shell and the lower shell are configured to nest at least partially within each other when the interbody implant is in an undeployed state.

[0104] Embodiment 32. The expandable interbody implant of embodiment 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 or 31, wherein the proximal cage and the distal cage further have side walls configured to contact the inner surfaces of the side walls of the upper shell and the lower shell, respectively, to provide structural support for the interbody implant.

[0105] Embodiment 33. The expandable interbody implant of embodiment 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31 or 32, wherein an edge of at least one side wall of the upper shell has one or more protrusions and an edge of at least one side wall of the lower shell has one or more recesses configured to receive the one or more protrusions of the upper shell so as to provide greater structural integrity to the interbody implant when the interbody implant is in an undeployed state.

[0106] Embodiment 34. The expandable interbody implant of embodiment 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32 or 33, further comprising a layer of porous material on the upper surface of the upper shell and / or the lower surface of the lower shell, the layer of porous material being disposed within a notch or recess in the upper and / or lower surface.

[0107] Embodiment 35. The expandable interbody implant of embodiment 34, wherein the layer of porous material comprises one or more sheets of porous titanium alloy.

[0108] Embodiment 36. An insert for use with the expandable interbody implant of embodiment 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, or 35, a handle portion including an extension portion, the extension portion having a cannula extending from a proximal end of the handle portion to a distal end of the extension portion; an engagement portion having an engagement mechanism on a distal end of the extension portion configured to engage the interbody implant and at least one counter-torque extension portion configured to prevent rotation of the interbody implant while the engagement mechanism is engaged with or disengaged from the interbody implant; a deployment tool having a handle and an extension configured to slide and rotate within a cannula in the handle portion, the extension having a tip configured to extend into the interbody implant to engage the adjustment screw; It is equipped with An insert in which the interbody implant transitions from an undeployed state to a deployed state or from a deployed state to an undeployed state by rotating a deployment tool engaged with an adjustment screw.

[0109] Embodiment 37. The insert of embodiment 36, wherein the handle further has an engagement knob configured to rotate the engagement mechanism.

[0110] Embodiment 38. An insert of embodiment 36 or 37, wherein the handle further has a deployment indicator configured to indicate the degree of deployment of the interbody implant achieved by rotation of the deployment tool.

[0111] Embodiment 39. The insert of embodiment 38, wherein the deployment tool is configured to provide an initial degree of deployment of the interbody implant.

[0112] Embodiment 40. The insert of embodiment 39, wherein the initial degree of deployment is greater than about 0°, greater than about 2°, greater than about 4°, or greater than about 6°.

[0113] Embodiment 41. A method of implanting the expandable interbody implant of embodiment 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, or 35, comprising: placing the interbody implant in a folded state within the disc space using the insert; Deploying the interbody implant by rotating the control knob of the inserter and then rotating the adjustment screw; A method for releasing a deployed interbody implant from an insert.

[0114] Embodiment 42. The method of embodiment 41, wherein a material that promotes bone growth is injected into the interbody implant through an opening in the proximal end of the interbody implant before releasing the deployed interbody implant from the insert.

[0115] Embodiment 43. A method of implanting the expandable interbody implant of embodiment 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, or 35, comprising: 40. The interbody implant of claim 36, 37, 38, 39 or 40 is placed in a folded state in the disc space, Deploying the interbody implant by rotating the control knob of the inserter and then rotating the adjustment screw; A method for releasing a deployed interbody implant from an insert.

[0116] Embodiment 44. The method of embodiment 43, wherein a material that promotes bone growth is injected into the interbody implant through the proximal opening of the cannula before releasing the deployed interbody implant from the insert.

[0117] While particular embodiments have been shown and described herein, it should be understood that various other changes and modifications can be made without departing from the spirit and scope of the claimed subject matter. Moreover, although various aspects of the claimed subject matter are described herein, such aspects need not be utilized in combination. It should be noted that although the instruments, systems, and methods described herein are described with a posterior approach, the instruments, systems, and methods described herein may also be used with other surgical procedures, including lateral or anterior approaches.

[0118] Unless otherwise indicated, all numbers expressing quantities of ingredients, properties, e.g., molecular weight, reaction conditions, and the like, used in the specification and claims should be understood to be modified in all instances by the term "about." Accordingly, unless indicated to the contrary, the numerical parameters set forth in the specification and appended claims are approximations that may vary depending on the desired properties sought to be obtained by embodiments of the present disclosure. At the very least, and without attempting to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of recited significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the present disclosure are approximations, the numerical values ​​set forth in the specific examples are reported as precisely as possible. However, any numerical value inherently contains certain errors necessarily resulting from the standard deviation obtained in their respective testing measurements. In one embodiment, the terms "about" and "approximately" refer to a numerical parameter within 10% of the stated range.

[0119] As used in the context of describing embodiments of the present disclosure (particularly in the context of the claims that follow), the terms "a," "an," "the," and similar references should be construed to cover both the singular and the plural unless otherwise indicated herein or clearly contradicted by context. The recitation of ranges of values ​​herein is merely intended to serve as a shorthand method of individually referring to each separate value falling within that range. Unless otherwise indicated herein, each separate value is incorporated into the specification as if set forth individually herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or clearly contradicted by context. The use of any and all examples or exemplary language (e.g., "etc.") described herein is intended merely to further clarify embodiments of the present disclosure and does not pose a limitation on the scope of the disclosure. No language described herein should be construed as indicating any non-claimed element essential to the practice of embodiments of the present disclosure.

[0120] Groupings of alternative elements or embodiments disclosed herein should not be construed as limitations. Each group member may be referenced and claimed individually or in any combination with other members of the group or other elements described herein. It is anticipated that one or more members of a group may be included in, or deleted from, a group for convenience and / or patentability. When any such inclusion or deletion occurs, the specification shall be deemed to include the group as modified to satisfy all Markush group descriptions used in the appended claims.

[0121] Certain embodiments are described herein, including the best way known to the inventors for carrying out embodiments of the present disclosure. Of course, variations on these described embodiments will become apparent to those skilled in the art upon reading the foregoing description. The inventors anticipate that such variations will be readily apparent to those skilled in the art, and intend that the embodiments of the present disclosure may be practiced otherwise than as specifically described herein. Accordingly, this disclosure includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable patent law. Furthermore, any combination of the above-described elements in all possible variations is included in the disclosure unless otherwise indicated herein or otherwise clearly contradicted by context.

[0122] Specific embodiments disclosed herein may be further limited in the claims using the phrases "consisting of" or "consisting essentially of." When used in a claim, whether as filed or added per amendment, the transitional phrase "consisting of" excludes any element, step, or ingredient not specified in the claim. The transitional phrase "consisting essentially of" limits the claim to the materials or steps specified and to materials or steps that do not materially affect one or more basic and novel characteristics. Embodiments of the present disclosure so claimed are inherently or expressly described and enabled herein.

[0123] Furthermore, when any reference is made throughout this disclosure to patents and publications, each of these references and publications is herein individually incorporated by reference in its entirety.

[0124] Finally, it should be understood that the embodiments disclosed herein are illustrative of the principles of the present disclosure. Other modifications that may be adopted are within the scope of the present disclosure. Thus, by way of example and not of limitation, alternative configurations of the embodiments of the present disclosure may be used in accordance with the teachings herein. Accordingly, the present disclosure is not limited to that precisely as shown and described.

[0125] Related Applications This application claims priority to U.S. Provisional Application No. 62 / 985,610, filed March 5, 2020, and U.S. Provisional Application No. 63 / 062,663, filed August 7, 2020, the entire contents of both of which are incorporated herein by reference.

Claims

1. an upper shell having a proximal end and a distal end, defining an upper surface extending from the proximal end to the distal end and configured to engage an inferior surface of a first vertebral body, and further having a pair of side walls, at least one of the side walls having a first angled slot extending distally along the side wall in a direction away from the upper surface; a lower shell having a proximal end and a distal end, defining a lower surface extending from the proximal end to the distal end and configured to engage the superior surface of a second vertebral body, and further having a pair of side walls, at least one of the side walls having a second angled slot extending distally along the side wall and away from the lower surface; a control assembly disposed between the upper and lower shells, the control assembly having interlocking proximal and distal cages and an adjustment screw defining a longitudinal axis, the proximal cage having proximal and distal bores, the distal cage having a proximal bore, and the adjustment screw extending through the distal bore of the proximal cage; It is equipped with a proximal portion of the proximal cage having a pair of upper hinge points about which the upper shell rotates and a pair of lower hinge points about which the lower shell rotates; the distal cage having a first lateral protrusion configured to engage the first angled slot and a second lateral protrusion configured to engage the second angled slot; Rotation of the adjustment screw causes the distal cage to translate along the longitudinal axis, which in turn moves the distal ends of the upper and lower shells apart from an undeployed state to a deployed state; An expandable interbody implant, wherein the adjustment screws are twin screws having a proximal screw and a distal screw, the proximal screw having a screw hole opening at a distal end, and the distal screw threadably engaging the screw hole.

2. The expandable interbody implant of claim 1 , wherein a distal end of the distal screw engages the distal cage such that the distal screw is rotationally fixed relative to the distal cage.

3. The expandable interbody implant of claim 1 , wherein the distal hole of the proximal cage is threaded and the adjustment screw threadably engages the threaded distal hole of the proximal cage.

4. The expandable interbody implant of claim 1 , wherein a distal end of the adjustment screw is configured to abut an interior surface at the distal end of the distal cage.

5. The expandable interbody implant of claim 1 , wherein the proximal cage further comprises a retaining pin configured to hold the adjustment screw in a predetermined longitudinal position relative to the proximal cage.

6. 10. The expandable interbody implant of claim 1, wherein the distal cage further comprises a distal angled surface configured to slidingly engage respective angled surfaces on the upper and lower shells.

7. 10. The expandable interbody implant of claim 1, wherein the distal cage further comprises rounded upper and lower surfaces configured for sliding engagement with inner surfaces of the upper and lower shells, respectively.

8. The expandable interbody implant of claim 7 , wherein the rounded upper surface and the rounded lower surface carry rods secured to the distal cage.

9. The expandable interbody implant of claim 8 , wherein the rod functions as both a first lateral projection and a second lateral projection of the distal cage.

10. The expandable interbody implant of claim 8 , wherein the rod comprises a material having a coefficient of friction lower than the coefficient of friction of the material forming the distal cage.

11. 10. The expandable interbody implant of claim 1, further comprising expandable upper and / or lower retention protrusions configured to expand when the expandable interbody implant transitions from an undeployed state to a deployed state.

12. 12. The expandable interbody implant of claim 11, wherein the upper retention protrusions and / or the lower retention protrusions are configured to retract when the expandable interbody implant transitions from a deployed state to an undeployed state.

13. the upper shell has an upper opening on the upper surface toward a distal end of the upper shell, the upper opening configured to allow an expandable upper retention protrusion to pass through the upper opening when expanded; 12. The expandable interbody implant of claim 11, wherein the lower shell has a lower opening on the lower surface toward a distal end of the lower shell, the lower opening configured to allow an expandable lower retention protrusion to pass through the lower opening when expanded.

14. 12. The expandable interbody implant of claim 11, wherein the upper and / or lower retention protrusions are pivotally coupled to a distal cage of the control assembly.

15. 15. The expandable interbody implant of claim 14, wherein translation of the distal cage along the longitudinal axis causes the upper and / or lower retention prongs to expand or retract.

16. the distal cage further includes a rounded upper surface and a rounded lower surface configured to slidingly engage inner surfaces of the upper shell and the lower shell, respectively; the rounded upper surface and the rounded lower surface are provided with rods fixed to the distal cage; 12. The expandable interbody implant of claim 11, wherein the upper and / or lower retention prongs are attached to respective rods of the distal cage.

17. 10. The expandable interbody implant of claim 1, wherein in an undeployed state, the side walls of the upper and lower shells abut one another to enclose the control assembly.

18. 2. The expandable interbody implant of claim 1, wherein the distal ends of the upper and lower shells are curved to surround the distal end of the distal cage when the interbody implant is in an undeployed state.

19. The expandable interbody implant of claim 1 , wherein at least one of the upper shell, the lower shell, the proximal cage, the distal cage, and the adjustment screw comprises a porous material.

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