Adjustable lordosis anchor and impactor
Patent Information
- Application Number
- JP2026057355
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-03-31
- Filing Date
- 2026-03-31
- Publication Date
- 2026-10-14
Smart Images
Figure 2026167635000001_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates generally to devices and methods for promoting intervertebral fusion, and more specifically to anchors for securing expandable fusion devices, as well as related systems, instruments, and methods.
Background Art
[0002] A common procedure for addressing pain associated with intervertebral discs degenerated by various factors (e.g., trauma or aging) is the use of intervertebral fusion devices to fixate one or more adjacent vertebral bodies. Generally, to fixate adjacent vertebral bodies, the intervertebral disc is first partially or completely removed. An intervertebral fusion device is then inserted between adjacent vertebrae to maintain normal intervertebral spacing and restore spinal stability, thereby facilitating intervertebral fusion. In some cases, the intervertebral fusion device may be secured with one or more bone anchors, such as bone screws.
[0003] However, existing anchors have drawbacks including insufficient fixation, potential expulsion, difficult installation along a range of height and lordosis options, and / or complex instruments for installation. For example, conventional anchor guides hold the anchor at a specific height and trajectory, which are incompatible with adjustable lordosis spacers because the intervertebral space can be expanded along a range of height and lordosis options. Accordingly, there exists a need for improved anchors that can provide fixation and expulsion resistance with improved insertion and removal instruments and techniques.
Summary of the Invention
[0004] To meet this and other needs, implants, systems, instruments, and methods for performing intervertebral fusion and spinal stabilization are provided. In particular, bone anchors can be adapted to intervertebral implants such as adjustable lordotic interbody spacers placed by the ALIF (anterior lumbar interbody fusion) approach. Expandable implants are inserted into the intervertebral disc space at a minimum height and are then configured to expand axially to restore height loss in the intervertebral disc space, achieve normal spinal alignment, and / or distribute the load across the vertebral end plates. The implants can also be varied in lordosis angle, independently of their expansion. One or more bone anchors may be inserted through the end plates of expandable implants to ensure that the implants remain firmly fixed within the vertebral space. Thus, bone anchors are configured to provide immediate stabilization, fixation, and resistance to repulsive forces that could dislodge the implants. In contrast to conventional designs where bone anchors utilize threaded holes for screw engagement with instruments, bone anchors define a threadless slot configured to seamlessly engage with the corresponding inserter tip. The inserter tip can be secured to the threadless slot, for example, by a quarter-turn connection to the anchor, providing freehand installation of each anchor. The threadless mounting interface significantly improves the ease of anchor installation, insertion, and / or removal, thereby streamlining the surgical process.
[0005] According to one embodiment, a bone anchor for fixing an intervertebral implant includes a spherical head and a curved blade extending therefrom. The spherical head defines a threadless opening including a vertical slot that communicates with an internal spherical pocket defined within the spherical head. The vertical slot has a narrow width defined between opposing flat surfaces and an elongated length longer than that width. The vertical slot is aligned with the longitudinal axis of the anchor. The spherical head includes a raised projection located below the vertical slot, creating a thickened wall region. The raised projection has a radius smaller than the radius of the spherical head and a width larger than the width of the vertical slot.
[0006] This anchor may include one or more of the following features: The vertical slot may have an oval shape. The vertical slot may be offset toward the top of the spherical head such that the upper end of the vertical slot cuts deeper into the spherical head relative to the lower end of the vertical slot. The internal spherical pocket has a diameter greater than the width of the vertical slot, thereby forming a protrusion beneath the sides of the vertical slot. Each side of the vertical slot may define a symmetrical lip, the top of each lip may be cut off in a plane. The curved blade may include an elongated fin, which ends away from the concave surface of the blade such that the elongated fin is roughly perpendicular to the blade.
[0007] According to one embodiment, the spinal stabilization system includes an expandable implant and a bone anchor. The expandable implant has an upper end plate, a lower end plate, and an actuator assembly which includes a movable forward actuator, a movable backward actuator, and a stationary backward actuator, positioned between the upper and lower end plates to independently control the anterior and posterior heights of the implant. The bone anchor is insertable into adjacent bone through the upper or lower end plate. The bone anchor has a spherical head and a curved blade extending therefrom. The spherical head defines a threadless opening including a vertical slot that communicates with an internal spherical pocket defined within the spherical head. The vertical slot has a narrow width defined between opposing flat sides and an elongated length longer than that width. The vertical slot is aligned with the longitudinal axis of the anchor. The spherical head includes a raised projection located below the vertical slot, creating a thickened wall region. The raised projection has a radius smaller than the radius of the spherical head and a width larger than the width of the slot.
[0008] This spinal stabilization system may include one or more of the following features: The upper and / or lower end plates may define a socket configured to receive the spherical head of a bone anchor, which guides the anchor into the adjacent bone. The socket may have a partial spherical notch, which provides a surface that fits against the spherical head of the anchor, allowing the anchor to rotate within the socket. The socket may define a stopper, which engages with a raised projection to restrict the rotation of the anchor, for example, limiting rotation of the anchor within the socket to a maximum of 20 degrees. The expandable implant may include a blocking screw, which, when rotated, covers a portion of the spherical head of the anchor, thereby preventing the anchor from coming out after insertion, and a raised projection prevents the threadless opening of the anchor from aligning with the blocking screw.
[0009] According to one embodiment, a method for implanting an orthopedic implant includes: (a) inserting an orthopedic implant between adjacent vertebrae, wherein the orthopedic implant comprises a first end plate defining a first socket, a second end plate defining a second socket, and an actuator assembly including a movable forward actuator, a movable backward actuator, and a stationary backward actuator positioned between an upper end plate and a lower end plate to independently control the anterior and posterior heights of the implant; (b) expanding the implant to adjust its height and / or lordosis; and (c) attaching a first anchor to a single anchor impactor instrument having a threadless distal tip configured to engage with a threadless opening of the anchor, wherein the instrument has a lateral slide The first anchor is attached to the device by rotating the inner shaft, the inner shaft having an elongated tip having a curved side with at least one flat side configured to engage with a corresponding flat side in a vertical slot of the anchor, and the outer sleeve having a distal end having a protruding rim, and the first anchor is attached to the device by rotating the inner shaft, the inner shaft rotating the anchor so that the protruding rim of the outer sleeve fits under the overhang along the side of the vertical slot, thereby securing the first anchor to the device, (d) pivoting the first anchor along the axis of the vertical slot to conform to a linear or angled trajectory of the first anchor, and (e) inserting the first anchor into a first socket of the first end plate to engage with the upper vertebra. The inner shaft may include a ball retainer configured to engage with a recess in the housing of the outer sleeve so that when the inner shaft is rotated relative to the outer sleeve, the inner shaft is held in one of two relative positions defined by the recess. The inner shaft can rotate 90 degrees relative to the stationary outer sleeve, which rotates the first anchor 90 degrees to secure it to the fixture. The vertical slot may have a length that allows the anchor to pivot based on the limitations imposed by the ends of the vertical slot.The method may further include (f) attaching the second anchor to the single-anchor impactor instrument by rotating the inner shaft and anchor so that the protruding rim of the outer sleeve fits under the protrusion along the side of the vertical slot, thereby fixing the second anchor to the instrument; (g) inserting the second anchor into the second socket of the second end plate and engaging it with the lower vertebra; and / or (h) disengaging the inner shaft from the outer sleeve by pressing down the release button in the outer sleeve to disengage it from the central shaft.
[0010] According to another embodiment, a single-anchor impactor instrument system includes an anchor and an instrument. The anchor has a spherical head and a curved blade extending therefrom. The spherical head defines a threadless opening that includes a vertical slot communicating with an internal spherical pocket defined within the spherical head. The vertical slot has flat sides that form a protrusion relative to the internal spherical pocket. The instrument has a threadless distal tip configured to engage with the threadless opening of the anchor. The instrument includes an internal shaft that is positionable through an external sleeve. The internal shaft includes an elongated tip with a truncated distal end. The elongated tip has curved sides along with at least one flat side configured to engage with one of the flat sides of the vertical slot when inserted into it. The external sleeve includes a distal end with a protruding rim. As the internal shaft rotates the anchor, the protruding rim of the external sleeve engages with the side of the vertical slot and under the protrusion, thereby securing the anchor to the instrument.
[0011] A single-anchor impactor instrument system may include one or more of the following features: The inner shaft may be configured to rotate 90 degrees relative to the outer sleeve, thereby rotating the anchor 90 degrees around the instrument's long axis, while the outer sleeve remains stationary, securing the anchor to the instrument. The protruding rim may have a curved surface, and as the anchor rotates, the curved surface of the rim of the outer sleeve fits into the internal spherical pocket and under the protrusion along the side of the vertical slot. The protruding rim may include a first rim portion and a second rim portion on either side of the elongated tip of the inner shaft. The vertical slot may have a length, which is longer than the length of the elongated tip, allowing the anchor to pivot on the non-threaded distal tip. The anchor may be able to pivot up to 22 degrees on the non-threaded distal tip to facilitate angled insertion of the anchor. The elongated, truncated distal end may have a curvature that matches the curvature of the internal spherical pocket, such that when the internal shaft is fully inserted into the non-threaded opening, the elongated, truncated distal end reaches the bottom within the internal spherical pocket.
[0012] According to another embodiment, a single-anchor impactor instrument system includes an anchor and an instrument. The anchor has a spherical head and a curved blade extending therefrom. The spherical head defines a threadless opening that includes a vertical slot communicating with an internal spherical pocket defined within the spherical head. The instrument has a threadless distal tip configured to engage with the threadless opening of the anchor. The instrument includes an inner shaft configured to rotate relative to a stationary outer sleeve. The inner shaft has a rear housing and a central shaft extending through it. The central shaft holds a shuttle and a plurality of washers. The outer sleeve has a housing and a tubular body for receiving the inner shaft through it. A lever is pivotably connected to the central shaft and the rear housing of the inner shaft. The shuttle and washers are configured to slide axially on the central shaft when the lever is actuated and the central shaft is moved axially. The device is configured to function in three positions: (a) in the first position, the device is ready to be attached to the anchor by extending the lever outward so that the threadless distal end is oriented to fit into the vertical slot of the threadless opening; (b) in the second position, the anchor is attached to the device in the unlocked position by rotating the inner shaft and lever 90 degrees relative to the first position, allowing the anchor to be angled along the axis of the vertical slot, and securing the threadless distal end to the threadless opening of the anchor; and (c) in the third position, the anchor is locked to the device by pivoting the lever flush with the outer sleeve, which pivots the central shaft back, pushes the shuttle forward, compresses the washer, and maintains tension on the central shaft to hold the anchor tightly against the threadless distal end of the device.
[0013] A single-anchor impactor instrument system may include one or more of the following features: A first and second position may be defined by a ball retainer configured to engage with a recess in the housing of the outer sleeve so that the inner shaft is held in one of two relative positions defined by the recess. A spring may be positioned around the central shaft and captured by a cap, which fits inside the rear housing, and the spring biases the central shaft forward. Washers may include spring washers, which are compressed to lock the anchor into the instrument. A lever may be pivotably connected to the central shaft and the rear housing of the inner shaft by a pin that serves as a pivot axis for the lever. In the first and second positions, the lever may be approximately perpendicular to the long axis of the instrument, and in the third position, the lever may be approximately parallel to the long axis of the instrument.
[0014] According to another embodiment, a single anchor impactor fixture includes an inner shaft and an outer sleeve aligned along the fixture axis. The inner shaft has a rear housing and a central shaft extending through it. The central shaft holds a shuttle and a number of washers. The outer sleeve has a housing and a tubular body for receiving the inner shaft through it. The fixture includes a lever for locking the anchor into the fixture. The lever is pivotably connected to the central shaft and the rear housing of the inner shaft by a lever pin. The shuttle and washers are configured to slide axially on the central shaft when the lever is actuated and the central shaft is moved axially. The fixture includes a ball retainer in the rear housing of the inner shaft, which is configured to engage with a recess in the housing of the outer sleeve so as the inner shaft is rotated relative to the outer sleeve, it is held in one of two relative positions.
[0015] A single-anchor impactor instrument may include one or more of the following features: The inner shaft may be configured to rotate 90 degrees while the outer sleeve remains stationary. The instrument may include a spring held by a cap to bias the central shaft forward, the cap fitting inside the rear housing of the inner shaft. The instrument may include a keying tab located on the underside of the rear housing, the keying tab fitting into a corresponding keying recess in the housing of the outer sleeve to ensure the lever is properly aligned. The instrument may include a release button having an opening for receiving the central shaft through which the inner shaft is configured to disengage from the outer sleeve. The central shaft may include a shoulder under the rear housing to define an engagement area for the release button. A washer may be located between the release button and the shuttle, the shuttle may be positioned between the washer and the lever pin.
[0016] In yet another embodiment, the kit may include multiple anchors of different sizes, expandable implants of different sizes and configurations, k-wires, and other components for performing the procedure. The kit may further include one or more instruments suitable for placing and / or removing implants, such as insertion devices or drive units, expansion devices, removal devices, anchor placement tools, and other tools and devices that may be suitable for surgery. [Brief explanation of the drawing]
[0017] This embodiment will be better understood from the detailed description and accompanying drawings. [Figure 1A] This is a perspective view of a bone anchor having a spherical head and a curved blade of varying length, according to one embodiment. [Figure 1B] This is a perspective view of a bone anchor having a spherical head and a curved blade of varying length, according to one embodiment. [Figure 2A] This is a front view of a bone anchor having an internal spherical pocket accessible via a vertical slot, according to one embodiment. [Figure 2B] FIG. 2 is a top view of a bone anchor having an internal spherical pocket accessible via a vertical slot, in accordance with one embodiment. [Figure 2C] FIG. 3 is a cross-sectional view of a bone anchor having an internal spherical pocket accessible via a vertical slot, in accordance with one embodiment. [Figure 3A] FIG. 4 is a front view of an expandable implant in an expanded position having a bone anchor for securing the implant to an adjacent vertebra, in accordance with one embodiment. [Figure 3B] FIG. 5 is a perspective view of an expandable implant in an expanded position having a bone anchor for securing the implant to an adjacent vertebra, in accordance with one embodiment. [Figure 4A] FIG. 6 is an enlarged view of the spherical head of an anchor including anti-rotation projections, in accordance with one embodiment. [Figure 4B] FIG. 7 is a front view of an anchor positioned through the upper end plate of an expandable implant where anti-rotation projections limit rotation of the anchor, in accordance with one embodiment. [Figure 5A] FIG. 8 is a perspective view of an adjustable lordosis expandable implant in a fully retracted position, in accordance with one embodiment. [Figure 5B] FIG. 9 is a perspective view of an adjustable lordosis expandable implant at maximum expansion, in accordance with one embodiment. [Figure 5C] FIG. 10 is a perspective view of an adjustable lordosis expandable implant at maximum lordosis, in accordance with one embodiment. [Figure 6A] FIG. 11 is a side view of an adjustable lordosis expandable implant in a fully retracted position, in accordance with one embodiment. [Figure 6B] FIG. 12 is a side view of an adjustable lordosis expandable implant at maximum expansion, in accordance with one embodiment. [Figure 6C] FIG. 13 is a side view of an adjustable lordosis expandable implant at maximum lordosis, in accordance with one embodiment. [Figure 7] FIG. 14 is an enlarged view of the unthreaded tip of an anchor insertion instrument for installing a bone anchor, in accordance with one embodiment. [Figure 8A]1 is a cross-sectional view of an insertion instrument positioned within an internal spherical pocket in a spherical head of a bone anchor that is rotated for attachment to or detachment from the anchor while providing linear or angled insertion and / or removal of the anchor, according to one embodiment. [Figure 8B] 1 is a cross-sectional view of an insertion instrument positioned within an internal spherical pocket in a spherical head of a bone anchor that is rotated for attachment to or detachment from the anchor while providing linear or angled insertion and / or removal of the anchor, according to one embodiment. [Figure 9] 1 is an exploded view of an insertion and / or removal instrument, according to one embodiment. [Figure 10] 1 is an enlarged cross-sectional view of a single anchor instrument, according to one embodiment. [Figure 11A] 1 is a perspective view of the anchor instrument when the instrument is ready to attach to a bone anchor. [Figure 11B] 1 is an enlarged view of the distal tip when the instrument is ready to attach to a bone anchor. [Figure 12A] 1 is a perspective view of the anchor instrument when the anchor is attached to the instrument but not locked. [Figure 12B] 1 is an enlarged view of the distal tip when the anchor is attached to the instrument but not locked. [Figure 13A] 1 is a perspective view of the anchor instrument when the anchor is attached to the instrument and locked. [Figure 13B] 1 is an enlarged view of the distal tip when the anchor is attached to the instrument and locked. [Figure 14A] 1 is a view showing an inner shaft and rear housing assembly of an anchor impactor that can be disassembled for cleaning, according to one embodiment. [Figure 14B] 1 is a view showing an outer sleeve of an anchor impactor that can be disassembled for cleaning, according to one embodiment. DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0018] Embodiments of this disclosure generally aim at devices, systems, instruments, and methods for intervertebral fixation and spinal stabilization. Specifically, bone anchors may be placed within intervertebral implants to form independent implants without the need for auxiliary fixation (e.g., additional screws, rods, etc.). The implants may include expandable implants such as adjustable lordotic interbody spacers placed by an ALIF (anterior lumbar interbody fusion) approach. The bone anchors may be positioned within the adjacent bone through the implant to ensure that the implant remains firmly fixed within the vertebral space. The bone anchors may include a spherical head with a curved blade, which helps prevent displacement by biomechanical forces exerted by the spine. Unlike conventional anchors with screw holes that require screw engagement with instruments which may be difficult to install in-situ, each bone anchor may define a non-threaded slot, which engages with a corresponding inserter tip for improved installation, insertion, and removal functions.
[0019] Expandable implants may be configured to be inserted into the intervertebral disc space at a minimum height, then expanded axially to restore height loss, provide normal spinal alignment, and / or distribute the load across the vertebral end plates. The implant can also be varied in lordosis angle, independently of its height expansion. After the implant is positioned between the vertebrae and expanded to the desired height and / or lordosis, bone anchors are inserted through their respective guide channels or holes in the implant. These channels or holes may help guide each anchor into the adjacent bone, for example, to optimize contact with the strongest areas of bone, thereby improving the overall stability of the implant. By firmly fixing the implant to the vertebral bone, the repulsive forces are effectively offset, thereby maintaining the integrity of spinal alignment and promoting fixation. Spinal fusion is typically used to eliminate pain caused by the movement of degenerated intervertebral disc material. Upon successful fixation, the fixation device is permanently fixed within the intervertebral disc space.
[0020] Minimally invasive surgery (MIS) can be used to preserve the anatomical structure of muscles by causing destruction only where necessary. The advantages of an MIS surgical approach are that it can reduce postoperative pain and improve patient recovery time. In one embodiment, an expandable fixation device and / or anchor may be configured to be placed within the surgical target site via an endoscopic tube. For example, the surgical site may be the intervertebral disc space located between two adjacent vertebrae. While the implant is particularly well-suited for use in anterior lumbar interbody fusion (ALIF), it will be readily apparent to those skilled in the art that it can be used in any number of suitable orthopedic approaches and procedures, such as a direct lateral approach facing coronal deformities. Other approaches may include, but are not limited to, posterior, lateral, anterolateral, posterolateral, or transforaminal approaches to the lumbar, cervical, or thoracic spine, as well as any non-spine applications such as the treatment of fractures. The terms implant, intervertebral body, intervertebral body implant, fixation device, spacer, and expandable device may be used interchangeably herein.
[0021] All components of the apparatus disclosed herein may be manufactured from any suitable material, including metals (e.g., titanium), metal alloys (e.g., stainless steel, cobalt-chromium alloys, and titanium alloys), ceramics, plastics, plastic composites, or polymer materials (e.g., polyether ether ketone (PEEK), polyphenylene sulfone (PPSU), polysulfone (PSU), polycarbonate (PC), polyetherimide (PEI), polypropylene (PP), polyacetal, or mixtures or copolymers thereof), and / or combinations thereof. In some embodiments, the apparatus may include radiopaque and / or radiopaque materials. Components may also be machined and / or manufactured using any suitable technique (e.g., additive manufacturing or 3D printing).
[0022] Referring here to the drawings, similar reference numerals may refer to similar elements, and Figures 1A-1B show a bone anchor 100 of varying length according to one embodiment. The bone anchor 100 may form part of a standalone intervertebral implant system, for example, by entering the upper and lower vertebrae and stabilizing the implant within the intervertebral space. Each bone anchor 100 may extend from a first posterior end 102 toward a second anterior end 104 configured to first enter the bone. The bone anchor 100 includes a head portion 106 and an elongated blade 108 extending therefrom. The head portion 106 may be located at the posterior end 102 of the anchor 100 and may have at least a partially spherical outer shape or surface. In one embodiment, the head portion 106 may be ball-shaped or spherical, thereby forming a generally spherical head 106. The spherical head 106 may be generally smooth and have no threads or anything similar.
[0023] As is most commonly seen in Figures 2A–2C, the spherical head 106 defines a threadless opening 110 configured to receive a portion of a fixture, such as a fixture 200. The threadless opening 110 includes a vertical slot 112 that is in fluid communication with an internal pocket 114 defined within the spherical head 106. When the anchor 100 is oriented in a front view, as shown in Figure 2A, the vertical slot 112 is centrally located and penetrates directly through the front portion of the sphere. The blade 108 extends from the rear portion of the sphere opposite the vertical slot 112. The slot 112 extends vertically so as to bisect the spherical surface of the head 106. The vertical slot 112 may be aligned with the longitudinal axis of the anchor 100. The vertical slot 112 may allow a fixture, such as a fixture 200, to be aligned directly and linearly with the anchor 100 without angular deviation. In this way, when engaged with the fixture 200, the anchor 100 can pivot only along the axis of the vertical slot 112.
[0024] The vertical slot 112 may have a narrow width 116 and an elongated length 118 that is longer than the width 116. The width 116 may be defined by the sides 120 of the slot 112. The sides 120 of the slot 112 may be generally linear or planar in order to maintain a uniform width 116 over the entire length of the slot. The length 118 may be defined by the ends 122, 124 of the slot 112. In one embodiment, the vertical slot 112 may have a generally oval shape. From the front view of Figure 2A, the first end, i.e., the upper end 122, of the slot 112 is located toward the top of the sphere, and the second end, i.e., the lower end 124, of the slot 112 is located toward the bottom of the sphere. It will be understood that these positional relationships do not limit the orientation of the anchor in use, and may be provided in any preferred orientation, position, or location as selected by the surgeon. The ends 122, 124 of the slot 112 may include curved or rounded edges that form, for example, a semicircle or other circular arc. The outer circumference of the slot 112, particularly along the ends 122, 124, may be slightly rounded, beveled, or curved toward the slot 112 from the outer surface of the sphere to improve tool insertion. The lower portion of the slot 112 may form an undercut for further engagement with instruments. In particular, an undercut 125 may be located beneath each end 122, 124 of the slot 112. The vertical slot 112 may be slightly offset toward the top of the sphere. For example, when the anchor 100 is oriented from the top view shown in Figure 2B, the upper end 122 of the slot 112 cuts deeper into the sphere relative to the lower end 124 of the vertical slot 112. Each side 120 of the slot 112 may further define a lip 126 or projection for further mating with an insertion instrument. Lip 236 may include a rounded ridge or bulge extending radially outward from the sphere. Lip 126 may include symmetrical lips of uniform size and shape on both sides of the slot 112, which do not extend along the entire length of the slot 112. In one embodiment, the symmetrical lip 126 may be located closer to the lower end 124 of the slot 112. The top of lip 126 may be cut off with a small plane 128 for better connection with the fixture.
[0025] Further attention to Figure 2C, the vertical slot 112 extends into the spherical head 106, providing access to the internal pocket 114. The internal pocket 114 forms a defined cavity within the spherical head 106. The internal pocket 114 may include a recessed area that defines, for example, a partially spherical, hemispherical, or fully spherical opening or cavity inside. The spherical pocket 114 may be centrally located within the spherical head 106 to maintain the structural integrity of the wall of the head 106. The configuration of the enlarged spherical cavity 114 relative to the narrow vertical slot 112 creates a protrusion along and / or below the side 120 of the slot 112. The protrusion creates a lip or barrier which can prevent the fixtures from being unintentionally disengaged from the anchor 100.
[0026] The spherical head 106 may also include a projection 130 on its underside to restrict any possible rotation of the anchor in the channel of the intervertebral implant once the intervertebral implant is inserted. The projection 130 may include a raised, rounded, or convex projection. The projection 130 may have a partially spherical or hemispherical outer surface with a radius smaller than the radius of the spherical head 106. The projection 130 may also be aligned with the longitudinal axis of the anchor 100. As best seen in Figure 2A, the projection 130 may be located below the lower end 124 of the slot 112 and have a symmetrical configuration with a width greater than the width 116 of the slot 112. The projection 130 creates a thickened wall region for the spherical head 106 between the inner pocket 114 and the outer surface of the projection 130. The edge of the projection 130 may seamlessly continue from the spherical outer surface by inclination or curve to provide a smooth transition, for example.
[0027] The elongated blade 108 extends away from the head portion 106 toward the front end 104 of the anchor 100. The blade 108 may be curved or may have curvature along its long axis. The blade 108 may be curved such that the concave surface 140 and the convex surface 142 extend from the rear end 102 toward the front end 104 of the anchor 100. The front end 104 may narrow toward a tip, bladed edge, or cutting edge, for example, to facilitate insertion into and through bone. Alternatively or additionally, one or more edges of the blade 108 may further include teeth, tapers, or bevels to further facilitate insertion of the anchor 100 into bone.
[0028] The blade 108 may include an elongated fin 148 extending away from the head portion 106 toward the front end 104 of the anchor 100. The fin 148 may extend away from the concave surface 140, for example, such that the elongated fin 148 is substantially perpendicular to the blade 108. In this way, the fin 148 may form a substantially T-shaped cross-section, which may help reduce the insertion force and / or increase the torsional stability of the anchor 100. It will be understood that any preferred blade 108 may be selected to maximize penetration into the bone while improving fixation when placed in the implant.
[0029] The anchor 100 can be fully 3D printed to conform to its unique geometric shape and to reduce manufacturing costs. The complex geometric shapes of the spherical pocket 114 and vertical slot 112 can be created using additive manufacturing methods such as laser sintering or fused deposition modeling. The raised lip 126 on the head 106 of the anchor 100 may also include a small plane 128 to avoid single-point overheating at this location. Localized overheating can deform the material or alter its microstructure. Overheating can also prevent the anchor from properly mating into the inserter. The anchor 100 is intended to be fully 3D printed without post-processing, except for buffing and / or deburring of any remaining support material on the underside of the anchor. Optionally, the anchor 100 may be printed with a roughened 3D printed surface configured to promote bone growth and improve rejection resistance. The anchor 100 may be supplied in kits in various shapes and / or lengths. For example, anchor 100 may have a length from the spherical center to the tip in the range of approximately 20 to 30 mm, or other suitable dimensions.
[0030] As most commonly seen in Figures 3A and 3B, bone anchors (one or more) 100 may be used in combination with intervertebral implants, such as expandable implants 10, to form an independent interbody fixation device. In one embodiment, the first bone anchor 100 may be placed in the upper vertebra through the upper portion of implant 10, while the second and third bone anchors 100 may be placed in the lower vertebra through the lower portion of implant 10. The bone anchors 100 may be placed in adjacent bone through implant 10 to ensure stability and robust attachment to the vertebra when driven into the vertebral body above and below the intervertebral disc space. The expandable implant 10 may include an adjustable lordotic interbody spacer, which is placed by an ALIF (anterior lumbar interbody fusion) approach or other suitable device. However, it will be understood that the number, position, and trajectory of the anchors 100 may be modified and may be used in combination with other suitable devices for optimal fixation.
[0031] Further observation of Figures 5A-5C and 6A-6C reveals that the expandable implant 10 extends along a central longitudinal axis between the front end (i.e., rear end 12) and the rear end (i.e., anterior end 14) of the device 10. The implant 10 includes an upper end plate 16 and a lower end plate 18 configured to engage with adjacent vertebrae, defining the height of the implant 10. The implant 10 may include an actuator assembly configured to extend the upper end plate 16 and the lower end plate 18. The actuator assembly may include a single actuator screw 22 that screws into an anterior actuator ramp 28 and a rear actuator ramp 30 to independently control the anterior and posterior heights of the implant 10.
[0032] In one embodiment, the expandable implant 10 may include three separate actuators 28, 30, and 32 positioned between the upper end plate 16 and the lower end plate 18, namely a movable forward actuator 28, a movable rear actuator 30, and a stationary rear actuator 32. One end of the actuator screw 22 is screwed into a forward actuator nut 24 located within the forward actuator 28, and the other end of the actuator screw 22 is screwed into a rear actuator nut attached to the stationary rear actuator 32. The actuator screw 22 is screwed through the movable rear actuator 30, translating the rear actuator 30 along its central longitudinal axis. When the actuator screw 22 and the forward actuator nut 24 are turned together, the movable rear actuator 30 moves toward the stationary rear actuator 32, forcing the upper end plate 16 and the lower end plate 18 apart and resulting in parallel expansion. When only the forward actuator nut 24 is turned, the movable forward actuator 28 moves independently, increasing its forward height and resulting in an increase in the lordosis angle.
[0033] The upper end plate 16 and the lower end plate 18 are interlocked with actuators 28, 30, and 32 via a plurality of mating ramps. Complementary mating ramps may include angled, inclined, or sloped surfaces that are slidably interlocked with each other to allow expansion of the upper end plate 16 and the lower end plate 18. The mating ramps allow controlled sliding movement on the complementary surfaces, thereby providing vertical displacement of the end plates 16 and 18.
[0034] The implant 10 is configured to be inserted into the intervertebral disc space in a contracted configuration. Figure 5A shows the implant 10 in a fully contracted configuration. Once inserted into the intervertebral disc space, the implant 10 expands in height to an expanded configuration to precisely restore normal spinal alignment and distribute the load across the vertebral end plates. Figure 5B shows the implant 10 in a fully expanded configuration at maximum expansion. Figure 5C shows the implant 10 in an expanded configuration at maximum lordosis. It will be understood that the implant 10 can expand to any desired height between these two extreme states. The anterior and posterior heights are independently adjustable to the desired lordosis profile. In this way, the height is adjustable to restore the height loss of the intervertebral disc space and the lordosis angle. It should be understood that references to the anterior and posterior ends, as well as anterior and posterior heights, refer to the direction of placement within the intervertebral disc cavity, such that the anterior end of the expandable fixation device 10 is first placed in the intervertebral disc cavity, followed by the posterior end of the expandable fixation device 10, and then the height and / or lordosis of the end plates 16, 18 are expanded. These and other directional terms may be used herein for illustrative purposes only and do not limit the orientation in which the device may be used.
[0035] Each end plate 16, 18 may include a front or rear rail 40 and a rear or front rail 42 extending between opposing lateral rails 44, 46. Rails 40-46 define an inner surface 50 and an opposite outer surface 52. The inner surface 50 may be configured to engage with the respective actuators 28, 30, 32, and the outer surface 52 may be configured to contact the adjacent vertebra. The outer surface 52 of each end plate 16, 18 may include a number of teeth 54 or other friction-increasing elements, such as protrusions, rough surfaces, keels, gripping projections, or trapping projections, configured to hold the device 10 within the intervertebral disc cavity. The end plates 16, 18 may be 3D printed using additive manufacturing techniques. Thus, the outer surface 52 may be fabricated using teeth and / or surface textures that can better promote bone surface growth. Each end plate 16, 18 may define a vertical window or through passage 56, thereby defining a central graft chamber within the implant 10. The window or through-hole 56 allows graft material or other therapeutically beneficial material to be filled into or grow through the implant 10.
[0036] The implant 10 can be fixed to an adjacent vertebra using one or more fixing screws and / or anchors, for example, anchors 100. For example, the anterior rail 42 may define at least one anchor socket 60, which is configured to receive the anchor 100 into the adjacent vertebra through the socket. In the illustrated embodiment, three sockets 60 for receiving three respective anchors 100 are provided on the upper end plate 16 and the lower end plate 18, with one socket 60 oriented upward into the superior vertebra and two sockets 60 oriented downward into the inferior vertebra. The sockets 60 may be surrounded by partial spherical notches or hemispherical recesses so that the anchor 100 can be angled into the adjacent vertebra. The partial spherical notches of the sockets 60 provide a surface that fits against the spherical head 106 of the anchor 100, allowing the anchor 100 to rotate within the sockets 60. The sockets 60 of the end plates 16 and 18 can accommodate both conventional lag screws and / or anchor fastenings such as anchors 100. In other words, the sockets 60 function as guides for bone screw holes and / or anchors 100. The diameter of the anchor head 106 may match the diameter of the bone screw, allowing either the anchor 100 or the screw to be inserted into either the bone screw hole or the socket 60 in the intervertebral space. Examples of bone screws and anchors are further described in U.S. Patent No. 11,554,023, which is incorporated herein by reference in its entirety for all purposes. While a given configuration of the sockets 60 is shown, it will be understood that the sockets 60 may exist in any preferred number, position, and configuration for fastening.
[0037] A cam-type blocking screw 62 may be used to prevent the anchor (or bone screw) from coming loose after insertion. The front rail 42 may define blocking screw holes 64 positioned next to each respective socket 60. The blocking screw holes may be provided with female threads to receive each threaded blocking screw 62. In one embodiment, three blocking screws 62 are screwed into end plates 16, 18 to secure the anchor 100 in each of the three sockets 60. The blocking screws 62 may have an expanding head with a drive recess and a threaded shaft. These blocking screws 62 allow one type of blocking screw to be used across all of the implant sockets 60. When the blocking screw 62 is rotated and engaged, a portion of the expanding head covers each anchor 100, thereby preventing movement of the installed anchor 100.
[0038] In one embodiment shown in Figure 4B, an anchor 100 installed through the upper end plate 16 is shown in more detail. The anchor head 106 includes a projection 130 on its underside to restrict any possible rotation of the anchor within the intervertebral socket 60 once the anchor is inserted. If the anchor 100 had a perfectly spherical head (without the projection), the anchor could rotate to a position where the vertical slot 112 could align with the blocking screw 62, creating a situation where the anchor is not protected from coming out. The anti-rotation projection 130 restricts the rotation of the anchor 100 to prevent this situation. For example, the anti-rotation projection 130 may restrict rotation to 20 degrees in any direction in which the projection 130 interferes with the geometry of the end plate. The sides of the projection 130 can abut against a step, limit, or other stop in the socket 60, which prevents further swiveling or rotation of the anchor 100. A 20-degree rotation of the anchor 100 allows for some variation during insertion, but prevents the slot 112 from aligning with the blocking screw 62. In this way, the blocking screw 62 prevents the anchor 100 from unintentionally disengaging from its seating position within the implant.
[0039] The rails 40-46 and / or inner surfaces 50 of each end plate 16, 18 may define one or more ramps 70, 72 configured to engage with their respective actuators 28, 30, 32, thereby separating the end plates 16, 18. For example, the end plates 16, 18 may define a rear ramp 70 along the rear rail 40, which engages with the rear actuators 30, 32. The end plates 16, 18 may define a front ramp 72 along the front rail 42 and a central ramp along the lateral rails 44, 46, which engage with the front actuator 28. The ramps 70, 72 may include ramp surfaces, angled surfaces, or inclined planes having a given gradient or angle of inclination. The ramps 70, 72 may have generally straight ramp surfaces, be curved, or be configured in any way suitable for slidable interlocking between components. Lamps 70, 72 may define male or female sliding lamps configured to mate with corresponding lamps on actuators 28, 30, 32.
[0040] The actuator assembly includes a movable forward actuator 28, a movable backward actuator 30, and a stationary backward actuator 32, positioned between the upper end plate 16 and the lower end plate 18, thereby providing expansion to the implant 10. The forward actuator 28 may define recesses or holes 88, such as threaded and unthreaded mounting holes 88, designed to work in conjunction with instruments for inserting and / or removing the implant. The actuators 28, 30, and 32 include one or more ramps configured to mate with corresponding forward ramps 70 and 72 on the end plates 16 and 18. The implant 10 allows for continuous expansion and extension over a particular range of the implant. This provides not only the ability to extend the vertebral body to a desired height, but also the ability to condense the device 10 for repositioning as needed. The implant 10 has the ability to converge the end plates 16 and 18 to provide lordosis while maintaining a large window for positioning bone grafts. By altering the lordosis angle, the implant 10 may be matched to the patient's natural lordosis, or it may be used to provide a specific lordosis at one of the treatment levels.
[0041] Once the implant 10 is placed in the intervertebral disc space, the anchor 100 can be installed to anchor the implant to the bone. Referring here to Figures 7 and 8A-8B, the anchor 100 is suitable for both linear and angled insertion and removal via the instrument 200. The instrument 200 includes a distal tip 202 that is receivable into the threadless opening 110 of the anchor 100 and configured to secure the anchor 100 to the instrument 200. The distal tip 202 is configured to rotate the anchor 100 so that the anchor 100 locks into the instrument 200 for insertion and / or removal. Conventional anchor designs have used threaded connections with instruments, which do not allow for insertion / removal at certain angles. Furthermore, mounting these connection threads in-situ can be extremely difficult. Therefore, a threadless interface between the instrument 200 and the anchor 100 provides an improved in-situ mounting method for the anchor 100. The threadless connection seamlessly engages with the inserter tip 202, significantly improving the ease of anchor installation, insertion, and / or removal, thereby streamlining the surgical process.
[0042] The device 200 may include an inner shaft 204 that is positionable through an outer sleeve 206. The inner shaft 204 includes an elongated tip 208 configured to fit into a vertical slot 112 of the anchor 100. The elongated tip 208 may have a partially rounded or spherical tip with a truncated distal end 210. The elongated tip 208 may have a rounded or curved side having at least one flat side 212 configured to fit into a corresponding flat side 120 of the vertical slot 112. The truncated end 210 may have a very small radius of curvature that matches the radius of the internal cavity 114. The outer sleeve 206 may include a distal end 220 having a reduced diameter. The distal face of the end 220 may include one or more protruding tabs or rims 222, which are configured to secure the device 200 to the anchor 100 when the anchor 100 is rotated. The rim 222 may conform to an arc or curvature shape that mimics the shape of the ends 122, 124 of the slot 112 of the anchor 100. The rim 222 may have a flat or planar surface 224 as its most distal surface. The flat surface 224 may be fully exposed when the elongated tip 208 is rotated 90 degrees. Each rim 222 may have a curved surface that conforms to the curvature of the internal spherical pocket 114 of the anchor 100. The protruding rim 222 may include a first rim portion and a second rim portion on either side of the elongated tip 208 of the inner shaft 204. When the anchor 100 is rotated with the inner shaft 204, the outer sleeve 206 remains stationary, thereby allowing the protruding rim(s) 222 to hook under the side 120 of the vertical slot 112 of the anchor 100, acting like a cam lock. Rim 222 can also act as a counter-torque to prevent the anchor from rotating within the bone, producing a windshield wiper effect often seen in threaded anchors, which can impair the anchor's ability to secure it to the bone.
[0043] As shown in the configuration depicted in Figure 7, the elongated tip 208 and the protruding rim 222 are aligned with each other and sized and dimensioned to fit into the vertical slot 112 of the anchor. The anchor 100 has an internal spherical pocket 114 inside the spherical head 106, which can be accessed through the vertical slot 112 in front of the anchor head 106. The inner elongated tip 208 extends into the internal pocket 114 of the anchor 100, with planes 212, 120 aligned with each other. The cut-off end 210 of the tip 208 can reach the bottom within the pocket 114 (for example, as shown in Figures 8A-8B). The vertical slot 112 allows the spherical tip 208, which has flat sides (one or more) 212, to be inserted into the internal spherical pocket 114, and then the internal shaft 204 rotates around the long axis of the fixture 200 to firmly engage the anchor 100 with the fixture 200. For example, the inner shaft 204 may rotate the anchor 100 by approximately 90 degrees or a quarter turn to securely engage the anchor 100 with the instrument 200. In this way, the inner shaft 204 rotates 90 degrees, thereby rotating the anchor 90 degrees around the long axis of the instrument 200, while the outer sleeve 206 remains stationary. The rotation of the anchor 100 causes the rim(s) 222 of the outer sleeve 206 to fit under the overhang along the side 120 of the vertical slot 112, thereby functioning in a manner similar to a cam lock. When engaged with the instrument 200, as best seen in Figures 8A–8B, the length 118 of the slot 112 also allows the anchor 100 to pivot along the axis of the vertical slot 112. The slot 112 allows the anchor 100 to pivot up to 22 degrees on the inserter tip 202. This variable angle allows for navigation around difficult anatomical structures through a small surgical incision. The variable angle of anchor 100 can be particularly useful during insertion when encountering a steep sacral inclination, for example, at L5 / S1.
[0044] The vertical slot 112 also functions as an anti-rotation feature to apply counter-torque to the anchor 100 against the inserter 200 while the internal spherical tip 208 is rotated 90 degrees inside the anchor head 106 to attach to or remove from the anchor 100. Conventional anchor designs used screw connections. In cases of overtightening or poor bone quality, attempting to loosen the inserter from the anchor by rotating these threads can cause the anchor to rotate within the bone or produce a windshield wiper, impairing the anchor's fixation to the bone. The quarter-turn anchor attachment method offers an improvement over screw connections in existing anchors, while also providing navigation for linear and angled insertion and / or removal of the anchor 100. The internal spherical pocket 114 also creates a surface that can be used to apply force to remove the anchor 100 using the same instrument 200 used for insertion.
[0045] Referring here to Figure 9, an exploded view of a single-anchor impactor instrument 200 according to one embodiment is shown. In one embodiment, the instrument 200 is configured to insert and / or remove an anchor 100 into a socket 60 of an adjustable lordotic intervertebral spacer 10. Unlike other instruments that insert anchors using an anchor guide and / or impactor rod, the instrument 200 is configured to allow freehand placement of each anchor 100, with the socket 60 of the implant 10 acting as a guide surface for the anchor 100. The single-anchor impactor 200 can be quickly and easily attached to the anchor 100 in a straight or angled trajectory, maintain a secure connection with the anchor 100 through embedding, and quickly release the anchor 100 once properly positioned. The anchor impactor 200 can also be used as a removal tool to pull the anchor 100 out of the bone and / or intervertebral spacer if necessary. The single anchor impactor device 200 may include an inner shaft 204 and an outer sleeve 206 aligned along the device axis, a lever 214 for locking the anchor 100 to the device 200, and a release button 216 for disassembling the device components.
[0046] The inner shaft 204 includes a rear housing 230 through which the central shaft 232 is received. The central shaft 232 may have a generally cylindrical body, which is positioned through the rear housing 230. The central shaft 232 extends from a proximal end 234 and terminates as a distal end 208 configured to engage with the anchor 100. The central shaft 232 may include an enlarged shoulder 236 near the proximal end 234, which is configured to hold a spring 254, and the central shaft 232 may further include a through opening 238 for securing a lever 214 to the central shaft 232 via a pin 245. The rear housing 230 may have a generally cylindrical body defining a central longitudinal opening 240 sized and dimensioned to receive the central shaft 232. The rear housing 230 may define a channel 242 configured to receive a portion of the lever 214, a lateral pin opening 244 for pinning the lever 214 to the rear housing 230 via a pin 245, and a lateral button opening 246 for receiving the release button 216. The outer surface 248 of the rear housing 230 may include a grip, such as a longitudinal slit / projection, which provides a surface for the user to rotate the inner shaft 204 relative to the outer sleeve 206.
[0047] The central shaft 232 holds the shuttle 250 and several washers 252. The shuttle 250 may include a tubular body positioned on the central shaft 232 within the rear housing 230. The washers 252 may include spring washers, such as Belleville washers, positioned on the central shaft 232 within the rear housing 230. During assembly, the shuttle 250 and several Belleville washers 252 slide along the central shaft 232. The central shaft 232 is inserted into the rear housing 230. The lever 214 is pinned to the central shaft 232 inside the rear housing 230 of the apparatus 200 via a pin 245. The shuttle 250 and washers 252 are configured to slide axially along the central shaft 232 when the lever 214 is actuated and the central shaft 232 is moved axially. A washer 252 may be positioned between the release button 216 and the shuttle 250, but the shuttle 250 is positioned between the washer 252 and the lever pin 245. A spring 254 is positioned around the central shaft 232 toward the proximal end 234 of the shaft 232. The spring 254 may be held by a cap 256, which fits inside the rear housing 230. The cap 256 may be welded to the rear housing 230 to permanently trap the spring 254 inside. As best seen in Figure 14A, the central shaft 232 may include a shoulder 258 below the rear housing 230, and the shoulder 142 defines an engagement area 260 for the release button 216. The base of the rear housing 230 may further define an opening 262 configured to receive one end of a ball retainer 264, such as a ball plunger. The other end of the ball retainer 264 may protrude from the rear housing 230 so that the retainer 264 is configured to engage with a recess 266 in the housing 272 of the outer sleeve 206. For example, two recesses 266 may be provided in the housing 272 of the outer sleeve 206 to hold the inner shaft 204 in one of two relative positions rotated 90 degrees apart from each other.
[0048] The anchor 100 can be locked to the fixture 200 via a lever 214. The lever 214 may include an elongated arm pivotable around a pin 245, which serves as the pivot axis. The central shaft 232 is positionable by the lever 214, which is positioned within a channel 242 in the rear housing 230. The pin 245 is receivable through an opening 244 in the rear housing 230, through an opening 266 in the lever 214, and through an opening 238 in the central shaft 232, thereby forming the pivot axis for the lever 214. At the opposite end, the lever 214 terminates at a free end 268. In the open position, the free end 268 of the lever 214 pivots away from the body of the rear housing 230, and the lever 214 can rotate as the inner shaft 204 rotates relative to the outer sleeve 206. In the open and unlocked positions, the lever 214 can be aligned approximately perpendicular to the long axis of the device 200. In the locked position, the lever 214 is pivoted flush with the body of the rear housing 230. In the locked position, the lever 214 can be aligned approximately parallel to the long axis of the device 200. The free end 268 can be slightly outward, so that the user can grasp the lever 214 and pivot it out of the rear housing 230 to return it to the unlocked position.
[0049] The outer sleeve 206 extends from the proximal end 270 to the distal end 220. The outer sleeve 206 may include a housing portion 272 and a tubular body 274 extending therefrom. The outer sleeve 206 defines a central through-opening 276 sized and dimensioned to receive the inner shaft 204 through it. The housing portion 272 may include a recessed area 278 at the proximal end 270, which receives a portion of the rear housing 230 of the inner shaft 204. For example, the rear housing 230 may fit inside the housing portion 272 so that the user can still access the outer grip 248 of the inner shaft 204 for rotation. The sides of the housing portion 272 of the outer sleeve 206 may define a channel 280 configured to receive a portion of the lever 214 when the inner shaft 204 is seated within the outer sleeve 206 and the lever 214 is actuated to the locked position. As best seen in Figure 14B, the outer sleeve 206 may define an alignment recess 282 configured to receive a corresponding alignment key 284, such as a keying tab. The alignment recess 282 may include a notch communicating with a central through-opening 276 sized and dimensioned to receive the lower keying tab 284 of the rear housing 230. The keying tab 284 may be seated within the keying recess 282 to ensure that the lever 214 is properly aligned during assembly. The outer surface 286 of the housing 272 may include a grip, such as a longitudinal slit / projection, which provides a surface for the user to hold the outer sleeve 206 when, for example, rotating the inner shaft 204 and holding the outer sleeve 206 in a stationary position. The tubular body 274 of the outer sleeve 206 may also define one or more windows 288, for example, to facilitate visibility and / or cleaning.
[0050] As best seen in Figure 10, the inner shaft 204 can be released from the outer sleeve 206 via a release button 216. The release button 216 may define a through-opening 290 through which the central shaft 232 is received. The release button 216 may be spring-loaded by a spring 292. The button 216 may be pinned to the outer sleeve 206 via a pin 294. When in the locked position, the button 216 is biased against the engagement surface 260 of the central shaft 232, causing the outer sleeve 206 to engage tightly with and lock the inner shaft 204. When the button 216 is pushed down to the unlocked position, the button 216 is released from the engagement surface 260, thereby allowing the inner shaft 204 and the outer sleeve 206 to be disassembled from each other, for example, to clean the instrument parts.
[0051] The single anchor impactor 200 can function in three main positions: (1) the device 200 is ready to be attached to the anchor 100; (2) the anchor 100 is attached to the device 200 in the unlocked position; and (3) the anchor 100 is attached to the device 200 in the locked position. In the first position, the anchor 100 is ready to be attached to the device 200. As is best seen in Figures 11A and 11B, the impactor device 200 is configured to be attached to the anchor 100. The lever 214 extends outward and is oriented in the first position such that the lever 214 is approximately perpendicular to the long axis of the device 200. The tip 208 of the inner shaft 204 is oriented to fit into the vertical slot 112 of the anchor 100. The flat side 212 of the tip 208 is configured to coincide with the corresponding flat side 120 of the vertical slot 112. The rim 222 of the outer sleeve end 220 also fits into the ends 122, 124 of the vertical slot 112 of the anchor 100. In this ready orientation, the spherical tip 208 of the inner shaft 204 can be fully inserted into the anchor head 106.
[0052] In the second position, the anchor 100 is attached to the instrument 200 but is not locked. As is best seen in Figures 12A and 12B, the lever 214 is also extended orthogonally here, but rotated 90 degrees relative to its first position. Thus, the inner shaft 204 is also rotated 90 degrees by turning the lever 214 to this second position. This rotates the distal tip 208 by 90 degrees, thereby rotating the anchor 100 by 90 degrees as well, while the outer sleeve 206 remains stationary. The rotated position of the distal tip 208 may also expose the flat surface 224 of the rim 222. When the anchor 100 is rotated relative to the stationary outer sleeve 206, the rim 222 catches under the side 120 of the slot 112. This prevents the anchor 100 from being removed from the instrument 200, but the angle of the anchor can still be adjusted.
[0053] In the third position, the anchor 100 is attached to and locked in the fixture 200. As is best seen in Figures 13A and 13B, the lever 214 pivots flush with the body 272 of the outer sleeve 206. The central shaft 232 is pulled back by lowering the lever 214. This compresses the Belleville washer 252, holding the anchor 100 tightly against the body of the fixture 200. When the lever 214 is lowered, it pulls the inner shaft 232 backward toward the proximal end. The backward axial movement of the central shaft 232 is stopped when the spherical tip 208 of the central shaft 232 tightly pulls the anchor 100 against the body of the fixture 200 (e.g., end 220). At this point, the lever 214 can be completed to be fully pushed down by pushing the shuttle 250 forward and compressing the washer 252. The compression of the washer 252 maintains tension on the central shaft 232, tightly pulling the anchor 100 to the distal end 220 of the outer sleeve 206.
[0054] Once locked into the instrument 200, the anchors 100 can be placed freehand into the bone through the implant 10. Each bone anchor 100 can be inserted through its respective socket 60 in the implant 10, which acts as a guide channel to assist in guiding the anchor 100 into the adjacent bone. An insertion force can be applied to the proximal end of the instrument 200, which is transmitted to the anchor 100, driving it into the correct position within the bone. After placement, the instrument 200 can be unlocked and removed from the anchor.
[0055] The anchor 100 can be unlocked by releasing the lever 214. When the lever 214 is lifted, the central shaft 232 can move forward, relieving the pull on the anchor 100. A return spring 254 ensures that the central shaft 232 is pushed fully forward. The lever 214 must be properly oriented relative to the rear housing 230 to perform a third position that locks the anchor 100 into the inserter 200. This ensures that the inner shaft 204 properly engages with the anchor 100 before tightly pulling the anchor 100. Similarly, the inner shaft 230 cannot be rotated to release the anchor 100 until the lever 214 is lifted fully vertically. This is a safety feature to prevent accidental release of the anchor 100.
[0056] The rear housing assembly may include a ball retainer 264, which, in conjunction with a recess 266 in the housing 272, holds the inner shaft 204 in one of two relative positions 90 degrees apart, namely, a ready-to-install position from the first position, and an installed position in the second and third positions. This provides the user with tactile feedback that the inner shaft 204 has been rotated to the correct position. The rear housing 230 may also include a keying tab 284 that prevents the rear housing assembly 230 from being inserted into the body 272 of the instrument 200 in the wrong orientation.
[0057] The anchor impactor instrument 200 may be configured to be easily disassembled for cleaning purposes or storage. The inner shaft 232 and rear housing assembly 230 can be removed from the body 272 of the instrument 200 by pressing down the release button 216 on the body of the instrument 200. A spring 292 returns the button 216 to the locked position, and a pin 294 keeps the button 216 in place on the instrument body.
[0058] The anchor impactor provides a quick and intuitive quarter-turn connection to a single anchor. A tab on the inserter tip provides counter-torque to the anchor, preventing the windshield wiper effect often seen with threaded anchors. The spherical mounting tip allows insertion and / or removal at angles of 0–22 degrees, accommodating challenging anatomical structures that are obstacles for threaded anchors. The same instrument can be used for inserting and removing anchors. The lever and compression washer design securely holds the anchor in the inserter, avoiding damage to the instrument tip. The lever design also ensures that the inner shaft cannot be accidentally rotated to disengage the anchor. The ergonomic design ensures that the user's hand holds the lever during insertion. The instrument is easily disassembled into easy-to-handle components for cleaning.
[0059] Although the present invention is described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the present invention is intended to cover modifications and variations of the invention, provided that they remain within the scope of the appended claims and their equivalents. For example, it is explicitly intended that all components of the various devices disclosed above can be combined or modified in any preferred configuration.
Claims
1. A bone anchor for fixing intervertebral implants, A bone anchor comprising a spherical head and a curved blade extending from the spherical head, wherein the spherical head defines a threadless opening including a vertical slot communicating with an internal spherical pocket defined within the spherical head, the vertical slot having a narrow width defined between opposing flat sides and an elongated length longer than the width, the vertical slot being aligned with the longitudinal axis of the anchor, and the spherical head including a raised projection located below the vertical slot, creating a thickened wall region, the raised projection having a radius smaller than the radius of the spherical head and a width larger than the width of the vertical slot.
2. The anchor according to claim 1, wherein the vertical slot has an oval shape.
3. The anchor according to claim 1, wherein the vertical slot is offset toward the upper part of the spherical head such that the upper end of the vertical slot cuts more deeply into the spherical head than the lower end of the vertical slot.
4. The anchor according to claim 1, wherein the internal spherical pocket has a diameter larger than the width of the vertical slot, thereby forming a protrusion below the side surface of the vertical slot.
5. The anchor according to claim 1, wherein each side of the vertical slot defines a symmetrical lip.
6. The anchor according to claim 5, wherein the top of each lip is cut off in a flat plane.
7. The anchor according to claim 1, wherein the curved blade includes an elongated fin, the elongated fin terminates away from the concave surface of the blade such that the elongated fin is substantially perpendicular to the blade.
8. A spinal stabilization system, An expandable implant having an upper end plate, a lower end plate, and an actuator assembly, wherein the actuator assembly includes a movable forward actuator, a movable rear actuator, and a stationary rear actuator positioned between the upper end plate and the lower end plate to independently control the forward and rear heights of the implant, A bone anchor insertable into an adjacent bone through the upper or lower end plate, comprising: a spherical head; and a curved blade extending from the spherical head, wherein the spherical head defines a threadless opening including a vertical slot communicating with an internal spherical pocket defined within the spherical head, the vertical slot having a narrow width defined between opposing flat sides and an elongated length longer than the width, the vertical slot aligning with the longitudinal axis of the anchor, and the spherical head including a raised projection located below the vertical slot, creating a thickened wall region, the raised projection having a radius smaller than the radius of the spherical head and a width larger than the width of the slot, A spinal stabilization system equipped with [the following features].
9. The spinal stabilization system according to claim 8, wherein the upper end plate and / or the lower end plate define a socket configured to receive the spherical head of the bone anchor, and the socket guides the anchor into the adjacent bone.
10. The spinal stabilization system according to claim 9, wherein the socket has a partial spherical notch, the notch providing a surface that fits against the spherical head of the anchor, thereby allowing the anchor to rotate within the socket.
11. The spinal stabilization system according to claim 9, wherein the socket defines a stopping portion, and the stopping portion engages with the raised projection to restrict the rotation of the anchor.
12. The spinal stabilization system according to claim 11, wherein the stopper allows the anchor in the socket to rotate by up to 20 degrees.
13. The spinal stabilization system according to claim 8, wherein the expandable implant includes a blocking screw, which, when rotated, covers a portion of the spherical head of the anchor, thereby preventing the anchor from coming out after insertion, and the raised projection prevents the threadless opening of the anchor from aligning with the blocking screw.
14. A method for implanting orthopedic implants, A step of inserting an orthopedic implant between adjacent vertebrae, wherein the orthopedic implant comprises a first end plate defining a first socket, a second end plate defining a second socket, and an actuator assembly including a movable forward actuator, a movable backward actuator, and a stationary backward actuator positioned between the upper end plate and the lower end plate to independently control the anterior and posterior heights of the implant; A step of expanding the implant to adjust its height and / or lordosis, A step of attaching a first anchor to a single anchor impactor instrument having a threadless distal end configured to engage with a threadless opening of the anchor, wherein the instrument includes an inner shaft positioned through an outer sleeve, the inner shaft includes an elongated tip having curved sides along with at least one flat side configured to engage with a corresponding flat side in a vertical slot of the anchor, the outer sleeve includes a distal end having a protruding rim, the first anchor is attached to the instrument by rotating the inner shaft, the inner shaft rotates the anchor so that the protruding rim of the outer sleeve fits under the overhang along the side of the vertical slot, thereby securing the first anchor to the instrument, A step of pivoting the first anchor along the axis of the vertical slot to fit the linear or angled trajectory of the first anchor, The steps include inserting the first anchor into the first socket of the first end plate and engaging it with the upper vertebra, Methods that include...
15. The method according to claim 14, wherein the inner shaft includes a ball retainer configured to engage with the recess in the housing of the outer sleeve such that when the inner shaft is rotated relative to the outer sleeve, the inner shaft is held in one of two relative positions defined by the recess.
16. The method according to claim 14, wherein the inner shaft rotates 90 degrees relative to the stationary outer sleeve.
17. The method according to claim 14, further comprising the length of the vertical slot enabling the anchor to pivot based on a limitation imposed by the end of the vertical slot.
18. The method according to claim 14, further comprising the step of attaching the second anchor to the single anchor impactor device by rotating the inner shaft and the anchor such that the protruding rim of the outer sleeve fits under the overhang along the side surface of the vertical slot, thereby fixing the second anchor to the device.
19. The method according to claim 18, further comprising the step of inserting the second anchor into the second socket of the second end plate and engaging it with the lower vertebra.
20. The method according to claim 14, further comprising the step of disassembling the inner shaft from the outer sleeve by pressing down the release button in the outer sleeve to disengage it from the central shaft.