Patent ID: 12193949

DETAILED DESCRIPTION OF THE INVENTION

The implants of this invention are designed for spinal fusion procedures to be used with autogenous bone graft in skeletally mature patients. While this invention is not so limited, the implants in one embodiment are intended for use at either one level or two contiguous levels in the lumbar spine, from L2 to S1, for the treatment of degenerative disc disease (DDD) with up to Grade I spondylolisthesis. DDD is defined herein as back pain of discogenic origin with degeneration of the disc confirmed by history and radiographic studies.

Expandable Implants

In one embodiment of the invention, the implants constitute expandable posterior lumbar interbody fusion (PLIF) implant products, although this invention is not limited to this specific target use.

With reference toFIGS.1and2,FIG.1is a perspective view of the expandable intervertebral implant20in a collapsed state.FIG.2is a perspective view of the expandable intervertebral implant20in an expanded state. In one embodiment of the invention, the expandable intervertebral implant20has a nose member1having a tapered distal end and a proximal end opposite the distal end. A pin2(not shown in this perspective) is disposed in a center of the nose member1and connects to an actuator3(not shown in this perspective) for centering the nose member1with the actuator3. The pin2maintains a position of the nose member1centered to the actuator3once the implant has been assembled. An upper body portion4, a wedge member5, a lower body portion6opposite the upper body portion are shown inFIGS.1and2. The wedge member5connects the upper body portion4to the lower body portion5. Translation of the wedge member5along the longitudinal axis of the implant, e.g., by turning of the actuator3, displaces the upper body portion4and the lower body portion6away from the wedge member5and away from each other, thereby expanding the intervertebral implant for example in the cephalad direction denoted inFIG.3.

FIG.3is a composite drawing showing a top-down exploded view, a frontal, side, and rear view, and a bottom view of the implant of the invention. As evident fromFIG.3, at least one of the upper body portion4and the lower body portion6comprises a corrugated surface4aor6afor engaging with vertebra. The upper body portion4and the lower body portion6provide the load bearing surfaces for the intervertebral loads once implant20has been implanted and expanded. As evident fromFIG.3, in one embodiment of the invention, the nose member is slidably connected to the upper body portion4and is slidably connected to the lower body portion5by the exterior dovetail grooves1a,1bon nose member1.

FIG.4Ais a schematic depiction of the individual components of the implant20, showing the relative positions of those components. As evident fromFIGS.3and4, actuator3is disposed between nose member1and wedge member5. In one embodiment of the invention, the wedge member comprises a first wedge5aand a second wedge5bconnected together by one or more rails5c. With reference toFIG.4A, nose member1centers by way of pin2and retains the head of actuator3during expansion of implant20.

FIG.4Bis an expanded view of the head3bof the actuator3having a flange3cwhich retains washer3dinto recess3e. Washer3dcan be made from similar or dissimilar materials as the actuator, and in one example, washer3dis made from polyetheretherketone (PEEK). Washer3dis merely one example of a frictional bearing that provides a frictional force retarding movement of the upper body portion relative to the lower body portion. As shown inFIG.4B, pin2fits into a reception hole3fdisposed on a central axis of the actuator3. While the circular and symmetric geometry shown inFIG.4Ais preferred, the washer and its recess need not be circular and split washers and spacers could be placed on the flange in asymmetric patterns.

Regardless of the material that washer3dis made of, washer3dserves multiple purposes in the present invention. In one embodiment, compression of washer3din the interface between nose member2and actuator3provides friction. This friction helps keep the parts centered and prevents binding of the components during expansion/contraction. The friction also provides additional resistance to post operation collapse of the cage.

During assembly, pin2is pressed into the nose member1with a portion of pin2extending beyond the distal end of nose member1. The upper body portion4and the lower body portion6are coupled to wedge member5along respective dovetails and dovetail groove with full engagement into a collapsed or non-expanded state. Actuator3is threaded into the wedge member5. The head position of actuator3is adjusted so that it is aligned with the mating slot in nose member1, while the vertical dovetails of the endplates are aligned with their mating dovetail grooves in nose member1. Next, washer3dis placed in recess3eon flange3cof the actuator. Then, the head of actuator3(with washer3din place) is slid into groove1cof nose member1, compressing washer3din the process to provide the friction noted above. Once the nose member1is close to alignment, pin2is pushed through an opening in the washer3dinto reception hole3fof actuator3. The part of pin2which formerly was protruding from the distal tip of nose member1is now flush with the distal tip of nose member1.

In one embodiment of the invention, the frictional bearing can be a wave spring applying an axial force on the head of the actuator. In another embodiment of the invention, the frictional bearing can be a spring loaded cap to apply an axial force on the head of the actuator. In still another embodiment, the frictional bearing can be a PEEK pellet (or pin) inserted in the nose piece and oriented to interfere with the head of the actuator, and thereby apply an axial force on the head of the actuator.

These latter embodiments are shown respectively inFIGS.4C,4D, and4E.

In particular,FIG.4Cshows a wave spring3d-1for application of an axial force to head3bof the actuator3. In this embodiment, there is no need to have recess3eon head3bof the actuator3(as shown inFIG.4B) although such a recess may be provided. In this embodiment, during assembly, pin2is pressed into the nose member1with a portion of pin2extending beyond the distal end of nose member1. The upper body portion4and the lower body portion6are coupled to wedge member5along respective dovetails and dovetail groove with full engagement into a collapsed or non-expanded state. Actuator3is threaded into the wedge member5. The head position of actuator3is adjusted so that it is aligned with the mating slot in nose member1, while the vertical dovetails of the endplates are aligned with their mating dovetail grooves in nose member1. Next, wave spring3d-1is placed on flange3cof the actuator. Then, the head of actuator3(with wave spring3d-1in place) is slid into groove1cof nose member1, compressing wave spring3d-1in the process to provide friction.

In particular,FIG.4Dshows a spring loaded cap for application of an axial force to head3bof the actuator3. In this embodiment, spring loaded cap3d-2ais axially compressed against mating flange3d-2bto provide an axial force on the head3bof the actuator3. In this embodiment, during assembly, pin2is pressed into the nose member1with a portion of pin2extending beyond the distal end of nose member1. The upper body portion4and the lower body portion6are coupled to wedge member5along respective dovetails and dovetail groove with full engagement into a collapsed or non-expanded state. Actuator3is threaded into the wedge member5. The head position of actuator3is adjusted so that it is aligned with the mating slot in nose member2, while the vertical dovetails of the endplates are aligned with their mating dovetail grooves in nose member1. Next, spring loaded cap3d-2awith the mating flange3d-2bis placed on flange3cof the actuator. Then, the head of actuator3(with spring loaded cap3d-2aand the mating flange3d-2bin place) is slid into groove1cof nose member1, compressing spring loaded cap3d-2ain the process to provide friction.

In particular,FIG.4Eshows a PEEK pellet3d-3(or pin3d-3) inserted in the nose member1and oriented to interfere with the head of the actuator for application of an axial force to head3bof the actuator3. In this embodiment, pin3d-3is axially compressed to provide an axial force on the head3bof the actuator3. In this embodiment, during assembly, pin2is pressed into the nose member1with a portion of pin2extending beyond the distal end of nose member1. The upper body portion4and the lower body portion6are coupled to wedge member5along respective dovetails and dovetail groove with full engagement into a collapsed or non-expanded state. Actuator3is threaded into the wedge member5. The head position of actuator3is adjusted so that it is aligned with the mating slot in nose member1, while the vertical dovetails of the endplates are aligned with their mating dovetail grooves in nose member1. Next, pin3d-3is inserted in a mating hole1din nose member1as shown inFIG.4E-1Thereafter, the head of actuator3is slid into groove1cof nose member1, and with pin3d-3in place, compresses pin3d-3to provide friction. The asymmetric placement of pin3d-3on one side of pin2also serves to assist in providing the frictional resistance.

In one embodiment of the present invention, regardless of the type of frictional bearing used, the frictional force prevents relative movement of the upper body portion4to the lower body portion6. In one embodiment, the frictional force prevents collapse of the expandable implant under its own weight.

In one embodiment of the invention, the actuator is disposed closer to the nose member than to a posterior of the implant. In general, the inventive implant expands by utilizing actuator3which is connected by a threaded connection to wedge member5, which contains for example a pair of wedges5a,5b. When rotated, actuator3pulls the wedges (as a set) closer to the nose member1of implant20and, in turn, drives the upper and lower body portions4,6away from the centerline of implant20. In other words, with actuator3being threadably connected to wedge member5, rotating actuator3translates the wedge member5along the longitudinal axis of implant20. Actuator3in one embodiment has a threaded outside surface3awith a head3bof the actuator, opposite the wedge member5, closer to the nose member1than to the posterior of implant20. In one embodiment, actuator3and wedge member5have respectively male and female threads to thereby advance wedge member5when the actuator3is turned.

As illustrated above, the present invention is an expandable (intervertebral) implant comprising an upper body portion4, a lower body portion6opposite the upper body portion4, a wedge member5connecting the upper body portion4to the lower body portion6, a nose member1having a tapered distal end and a proximal end opposite the distal end, the nose member1slidably connected to the upper body portion4and the lower body portion6, an actuator3disposed between the nose member1and the wedge member5, for translation of the wedge5member along a longitudinal axis of the implant, the actuator3on a first side slidably connected the nose member1and on a second side threadably connected to the wedge member and a pin2connects to the actuator3for positioning the nose member1relative to the actuator3. In one embodiment, the expandable implant includes a frictional bearing providing a frictional force retarding movement of the upper body portion relative to the lower body portion. In one embodiment, toward a side of the actuator3coupled to the nose member1, actuator3has a flange3c, a reception hole3fin the flange3cdisposed on a central axis of the actuator3for reception of the pin2, and a washer3ddisposed on the flange (e.g., in recess3e) and surrounding the reception hole3f. In one embodiment of the invention, as noted above, after assembly of the implant, washer3dis in a compressed state compressed between the actuator3and the nose member1, thereby providing a frictional force retarding movement of upper body portion4relative to lower body portion6. In one embodiment of the invention, washer3dis in the compressed state comprises the aforementioned frictional bearing.

In one embodiment of the invention, the implants comprise low profile implants with a minimal insertion height h for insertion into a collapsed intervertebral disc space. In this aspect of the invention, the height of the implant is that of the wedge member height, as seen inFIG.3, which constitutes the maximum expansion distance. Accordingly, in this aspect of the invention, back side of the second wedge comprises the posterior end of implant20and comprises an entire height of the implant. Once inserted (facilitated by its low profile in this embodiment), implant20can expand for example in the cephalad-caudal direction(s) to facilitate disc height restoration.

FIG.5is a schematic depiction of the individual components of the implant20with attention on the dovetail groove assembly construction, As seen inFIG.5, nose member1uses dovetail grooves24to slidably connect and guide expansion of the upper and lower body portions4,6and restrain any anterior-posterior movement of the upper and lower body portions4,6. Moreover, in one embodiment, dovetail grooves on the wedge member5hold and slidably connect the upper body portion4and the lower body portion6to the wedge member5. In another embodiment, dovetail grooves hold and slidably connect the upper body portion4and the lower body portion6to the nose member1. In another embodiment, a proximal end of nose member1comprises a pair of facing dovetail grooves1a,1bcomprising respective slots to receive therein the head3aof the actuator3.

In still another embodiment, a series of dovetail grooves connect the nose member1, the upper body portion4, the wedge member5, and the lower body portion6together. In still another embodiment, the nose member1slidably connects to the upper body portion4and the lower body portion6by a set of dovetail groove on an external surface of the nose member1. In still another embodiment, a set of dovetail grooves on the first wedge5aand the second wedge slidably connect the wedge member5to the upper body portion4and/or to the lower body portion6. In still another embodiment, a first set of dovetail grooves on the nose member1fix the nose member1to the upper body portion4and the lower body portion6, and a second set of dovetail grooves on the wedge member5fix the upper body portion4and the lower body portion6to the wedge member5.

FIG.6is a schematic depicting a bone graft window8in implant20. As shown inFIG.6, an opening in at least one of the upper body portion4and the lower body portion6is provided for bone graft window8. The graft window is also incorporated into wedge member5. In one embodiment of the invention, by disposing the actuator mechanism toward the nose of the implant20, a relatively large graft window8is provided for the implant, and graft material can be injected into the implant20once inserted and expanded in the patient. The relatively large graft window facilitates the bone growth and fusion process. In one embodiment, the graft opening can range from 25% to 60% of the endplate area (e.g., the area of the upper or lower body portion) depending on the footprint of implant20. Regardless of the opening size and configuration, in one embodiment, the implant device provides the capability to backfill bone graft material into a graft window passing all the way though the implant20.

FIG.7is a schematic depicting counter torque slots28of implant20and a through hole30in the posterior end of implant20. The counter torque slots28permit an entirety of implant20to be rotated, that is implant20as a unit is rotatable. The counter torque slots28prevent the implant from rotating, or tipping over, during expansion. The counter torque slots28stabilize the implant20against the torque being applied to the actuator during expansion. The through-hole30grants access for the driver to the actuator. The through-hole30also represents an opening for the insertion of bone graft material. In one embodiment of the invention, the wedge member5comprises a first wedge5aand a second wedge5bconnected together by a pair of rails5c. A through-hole in the first wedge5a, a second through-hole in the second wedge5b, and a spacing between the rails5ccomprise a passageway for an insertion tool to connect to and turn actuator3, and a passageway for bone graft material insertion.

In one embodiment of the invention, there is provided a system for stabilization of vertebra. This system utilizes any of the expandable implants described above; and an insertion tool which turns the actuator described above and thereby expands the implant. For example, actuator3shown above can be rotated by a T-7 hexalobular driver fitting the corresponding nut head32shown inFIG.7. Accordingly, in one embodiment, the insertion tool engages the counter torque slots to 1) provide a counter torque during expansion and 2) retain the implant20to an inserter supplying bone graft material during the procedure. The bone graft inserter can be cannulated. In one embodiment, the above-noted T-7 driver is placed through the center of the bone graft inserter and engages the actuator. Bone graft material is then pushed through the inserter into implant20after implant20has been expanded.

In another embodiment of the invention, as shown inFIGS.8A-1,8A-2,8A-3, and8B, there is provided an expandable (intervertebral) implant comprising an upper body portion4, a lower body portion6opposite the upper body portion4, a wedge member5extending along a longitudinal axis of the implant20and connecting the upper body portion4to the lower body portion6, a nose member1having a tapered distal end and a proximal end opposite the distal end, the nose member1slidably connected to the upper body portion4and the lower body portion6, an actuator3disposed offset from the longitudinal axis and disposed between the nose member1and the wedge member5, for translation of the wedge5member along a longitudinal axis of the implant, the actuator3on a first side slidably connected the nose member1and on a second side threadably connected to the wedge member5, and a pin2connecting to the actuator3.

FIGS.8A-2, and8A-3show respectively the collapsed and expanded states of the expandable implant. In the expanded state, there are both the graft window8and openings8aalong the lateral sides of the implant for the supply of graft material throughout the internal volume of the implant.

Optionally, as shown in the expanded view ofFIG.8B, toward the first side of the actuator3, the actuator3has a flange3c, a reception hole3fin the flange3cdisposed on a central axis of the actuator3for reception of pin2, and a washer3ddisposed on the flange (e.g., in recess3e) and surrounding the reception hole3f. Translation of the wedge member5along the longitudinal axis of the implant20displaces the upper body portion4and the lower body portion6away from each other, thereby expanding the intervertebral implant20. When washer3dis present and due to a relatively tight tolerance (with a thickness washer3dexceeding slightly the thickness of the recess3c), washer3dis compressed as the nose member1and the actuator3are assembled together. In this embodiment, as before, washer3din the compressed state comprises the aforementioned frictional bearing.

In one embodiment of the invention, as shown inFIG.8C, there is provided an expandable intervertebral implant having an asymmetric graft window8with a larger opening to an anterior side of the implant than to a posterior side of the implant20. Since the designation of anterior and posterior relates to a preferred direction for insertion into the patient, in general, there is provided an expandable intervertebral implant having an asymmetric graft window8with a larger opening to one side of the implant than to another, opposing side of implant20. In general, the terms superior, inferior, posterior, and anterior as used herein may refer to the orientation of the expandable implant as it is inserted between vertebrae. However, the invention is not so limited and these terms also define merely the relative orientation of the sides of the expandable implant to one another. For example, the superior and inferior terms refer to opposing sides to the implant for connection to the vertebrae, the opposing members on those sides expanding relative to each other. For example, the posterior and anterior terms refer to opposing sides to the implant which are positioned laterally across from each other, and in general transverse to the longitudinal axis of the implant.

While the asymmetric graft window8depicted inFIG.8Cis shown with the offset actuator ofFIG.8A, the present invention is not so limited, and the asymmetric graft window8can be used with the expandable implant shown inFIGS.1and2where either or both of the upper body portion4and the lower body portion6shown inFIGS.1and2have an asymmetric graft window8.

In one embodiment, as shown inFIG.8C, on a side of the implant opposite the off-axis actuator3, a pair of dovetail grooves1a,1bon nose member1engages dovetails4a,6adisposed respectively on the upper body portion4and the lower body portion6to hold and slidably connect the upper body portion4and the lower body portion6to the nose member1. Also, shown inFIG.8Cis the common dovetail groove1con the anterior side of nose member1which engages with dovetail4bon the upper body portion4and dovetail6bon the lower body portion6.

In one embodiment, as shown inFIG.8D, wedge member5comprises in order a first wedge5a, a pair of second (middle) wedges5c-1and5c-2, and a third wedge5bconnected together by a rail5c. That is the wedge member5comprises a leading wedge5a, an intermediate wedge5c-1and5c-2, and a trailing wedge5b. The pair of second (middle) wedges5c-1and5c-2are spaced apart from each other to provide more clearance for the graft window8.22. In one embodiment, the pair of wedges5c-1and5c-2comprises an anterior wedge5c-1and a posterior wedge5c-2with the anterior wedge5c-1has an anterior dovetail groove disposed outside the graft window8and with the posterior wedge5c-2having a posterior dovetail groove5c-2adisposed in the graft window8.

As illustrated inFIG.8E-1, wedge5bcontains dovetail grooves5b-1extending in this example along an entire length of the inclined surface5b-2of wedge5b. Complementary dovetails on the upper body portion4slide into the dovetail groves5b-1.

As illustrated inFIG.8E-2, the upper body portion4has dovetails4b-1which slide in dovetail grooves5b-1on wedge member5.

In one embodiment, posterior wedge5c-2is shorter in height than anterior wedge5c-1. The relative heights of posterior wedge5c-2and anterior wedge5c-1define a lordotic angle for the implant tapering downward toward a posterior side of the implant. Further, as seen inFIGS.8D and8E-1, anterior wedge5c-1has a) an upper half with a superior dovetail5c-1adisposed outside the graft window and b) a lower half with an inferior dovetail disposed outside the graft window. Also, as seen inFIGS.8D and8E-1, posterior wedge5c-2has a) an upper half with a superior dovetail5c-2adisposed inside the graft window and b) a lower half with an inferior dovetail groove disposed outside the graft window.

FIG.8Fis a schematic of an end view of an expanded state of the expandable implant shown inFIG.8A-3. As seenFIG.8F, in the expanded state on a posterior side of the implant, an upper ramp4dextending downward from the upper body portion4partially overlaps a lower ramp6dextending upward from the lower body portion6. In the collapsed state, the overlap is even more complete. Also, an upper dovetail groove4ein the upper ramp4don the posterior side engages the superior dovetail5c-2ainside the graft window and a lower dovetail groove6ein the lower ramp6don the posterior side engages the inferior dovetail5c-2bthat is disposed outside the graft window. On the anterior side, dovetail grooves4f,6fin respectively the upper and lower plates4,6engage the dovetails5c-1a,5c-1boutside the graft window.

The expandable implants of the present invention are not limited to the type of material that the implant is made of. The implants of this invention can be made of any material appropriate for human implantation and having the mechanical properties sufficient to be utilized for the intended purpose of spinal fusion, including various metals such as cobalt chrome, stainless steel or titanium including its alloys, various plastics including those which are bioabsorbable, and various ceramics or combination sufficient for the intended purpose. Further, the implants of this invention may be made of a solid material, a mesh-like material, a porous material and may comprise, wholly or in part, materials capable of directly participating in the spinal fusion process, or be loaded with, composed of, treated of coated with chemical substances such as bone, morphogenic proteins, hydroxyapatite in any of its forms, and osteogenic proteins, to make them bioactive for the purpose of stimulating spinal fusion. The implants of this invention may be wholly or in part bioabsorbable. Other materials for the implant device besides those specifically listed above can be used.

This invention is also not limited to the methods by which the implants are made. The individual components can be machined from solid stock pieces. Molding can be used to make the individual components. In this case, machining to final dimensions may or may not be in order. The surfaces once properly dimensioned can be coated with a variety of biocompatible coatings and/or surface treatments. Various coatings include for example calcium phosphate ceramics, such as tricalcium phosphate (TCP) and hydroxyapatite (HA), and hydroxyapatite (a naturally occurring material in bone). Moreover, If the implant is not made of bone, surfaces of the implant that contact bone may be treated to promote fusion of the implant to the bone. Treatment may include, but is not limited to, applying a hydroxyapatite coating on contact surfaces, spraying a titanium plasma on contact surfaces, and/or texturing the contact surfaces by scoring, peening, implanting particles in the surfaces, or otherwise roughening the surfaces of the implant.

Operation of Expandable Implants

In one embodiment of the invention, there is provided a method for stabilization of vertebra.FIG.9is a flowchart depicting this method. This method at1001attaches an insertion tool to any of the expandable implants described above. At1003, the method inserts one (or more) of the expandable implants into an intervertebral space between adjacent vertebrae; and at1005expands the expandable implant.

After the expandable implant has been expanded, at1007, the insertion tool may be removed (e.g., may be pulled from through hole30in the posterior end of implant20. At1009, bone graft material may then be inserted into the expanded implant filling the graft window8in situ. As noted above, the insertion of bone graft material promotes increased fusion.

This invention is not limited to a specific type of bone graft material. In general, a variety of bone graft materials are known and suitable for this invention. These typically comprise calcium phosphate-based or gel-based materials. Polymer-based bone graft substitutes containing (or not containing) collagen can be used. Ceramic bone graft substitutes can be used. In one embodiment, the implantable bone graft material comprises a composite of a ceramic and a polymer. The ceramic and the polymer can be present at a weight ratio ranging from about 10:1 ceramic to polymer to about 2:1 ceramic to polymer. Alternatively, the weight ratio of the ceramic to the polymer can range from about 2:1 (about 66% ceramic to about 33% polymer), from about 3:1 (about 75% ceramic to about 25% polymer), from about 4:1 (about 80% ceramic to about 20% polymer), from about 9:1 (about 90% ceramic to about 10% polymer), from about 10:1 (about 99% ceramic to about 1% polymer). Other bone graft materials besides those specifically listed above can be used.

In some embodiments, any of the implants and instruments described above (such as the insertion tool) can be used with additional implants and instruments. In some embodiments, the implants and instruments can be used with stabilization members, such as plates, screws, and rods. In addition, a multi-level construct can be formed, wherein any one or more of the implants20described above can be used on one level, while a similar or different implant (e.g., fusion or prosthetic) can be used on a different level.

STATEMENTS OF THE INVENTION

The following statements of the invention represent various aspects of the invention.Statement 1. An expandable intervertebral implant comprising:an upper body portion;a lower body portion opposite the upper body portion;a wedge member connecting the upper body portion to the lower body portion;a nose member having a tapered distal end and a proximal end opposite the distal end, the nose member slidably connected to the upper body portion and the lower body portion;an actuator disposed between the nose member and the wedge member for translation of the wedge member toward the nose member;the actuator on a first side slidably connected the nose member and on a second side threadably connected to the wedge member;a pin connects to the actuator for positioning the nose member relative to the actuator; anda frictional bearing contacting the actuator and providing a frictional force retarding movement of the upper body portion relative to the lower body portion,whereintranslation of the wedge member along the longitudinal axis of the implant displaces the upper body portion and the lower body portion away from each other, thereby expanding the intervertebral implant.Statement 2. The implant of statement 1, further comprising:a flange,a reception hole in the flange disposed on a central axis of the actuator for reception of the pin, anda washer disposed on the flange and surrounding the reception hole,wherein the washer comprises the frictional bearing held in a compressed state between the actuator and the nose member, thereby providing the frictional force retarding movement of the upper body portion relative to the lower body portion.Statement 3. The implant of any statement above, further comprising an opening in at least one of the upper body portion and the lower body portion for a bone graft window.Statement 4. The implant of any statement above, wherein at least one of the upper body portion and the lower body portion comprises a corrugated surface.Statement 5. The implant of any statement above, wherein the actuator is threadably connected to the wedge member such that rotating the actuator translates the wedge member along toward the nose member.Statement 6. The implant of any statement above, wherein dovetails on the wedge member hold and slidably connect the upper body portion and the lower body portion to the wedge member.Statement 7. The implant of any statement above, wherein dovetail grooves on the nose member hold and slidably connect the upper body portion and the lower body portion to the nose member.Statement 8. The implant of any statement above, wherein a drive end of the actuator opposite the nose member is configured to connect with an insertion tool for insertion of the implant between vertebrae.Statement 9. The implant of any statement above, wherein a head of the actuator, opposite the wedge member, is located in the nose member.Statement 10. The implant of any statement above, whereinthe actuator by turning advances the wedge member toward the nose member to expand the implant, andthe actuator and the wedge member have respectively male and female threads to thereby advance the wedge member when the actuator is turned.Statement 11. The implant of any statement above, wherein the pin maintains a position of the nose member relative to the actuator once the implant has been assembled, the position being offset from a longitudinal axis of the wedge member.Statement 12. The implant of any statement above, wherein, on a posterior side of the implant, plural dovetail grooves in the nose member respectively hold and slidably connect the upper body portion and the lower body portion to the nose member.Statement 13. The implant of statement 12, wherein, on an anterior side of the implant, a common dovetail groove in the endplate holds and slidably connects the upper body portion and the lower body portion to the nose member.Statement 14. The implant of any statement above, whereina through-hole in the wedge member comprises a passageway for an insertion tool to connect to and turn the actuator.Statement 15. The implant of any statement above, whereinthe wedge member comprises a leading wedge, an intermediate wedge, and a trailing wedge connected together by a pair of rails, andthe intermediate wedge comprises a pair of wedges with a gap in between.Statement 16. The implant of any statement above, wherein a posterior wedge of the pair of wedges is shorter in height than an anterior wedge of the pair of wedges, relative heights of the posterior wedge and the anterior wedge defining a lordotic angle tapering downward toward a posterior side of the implant.Statement 17. The implant of statement 16, wherein the anterior wedge has a) an upper half with a superior dovetail disposed outside the graft window and b) a lower half with an inferior dovetail disposed outside the graft window.Statement 18. The implant of statement 16, wherein the posterior wedge has a) an upper half with a superior dovetail disposed inside the graft window and b) a lower half with an inferior dovetail groove disposed outside the graft window.Statement 19. The implant of statement 18, wherein,in a collapsed state on a posterior side of the implant, an upper ramp extending downward from the upper body portion overlaps a lower ramp extending upward from the lower body portion, andan upper dovetail groove in the upper ramp on the posterior side engages the superior dovetail inside the graft window and a lower dovetail groove in the lower ramp on the posterior side engages the inferior dovetail that is disposed outside the graft window.Statement 20. The implant of any statement above, wherein, on an anterior side of the nose member, a dovetail groove comprises a slot to receive therein a head of the actuator.Statement 21. The implant of any statement above, wherein the wedge member extends along a longitudinal axis of the implant, and the actuator is disposed offset from the longitudinal axis.Statement 22. The implant of any statement above, wherein at least one of the upper body portion and the lower body portion has an asymmetric graft window with a larger opening to a first side of the implant extending along a length of the wedge member than to a second side of the implant opposite the first side.Statement 23. The implant of any statement above, wherein at least one of the upper body portion and the lower body portion has an asymmetric graft window with a larger opening to an anterior side of the implant than to a posterior side of the implant.Statement 24. An expandable intervertebral implant comprising:an upper body portion;a lower body portion opposite the upper body portion;a wedge member extending along a longitudinal axis of the implant and connecting the upper body portion to the lower body portion;a nose member having a tapered distal end and a proximal end opposite the distal end, the nose member slidably connected to the upper body portion and the lower body portion;an actuator disposed offset from the longitudinal axis of the wedge member and disposed between the nose member and the wedge member for translation of the wedge member along a longitudinal axis of the implant;the actuator on a first side slidably connected the nose member and on a second side connected to the wedge member;a pin connects to the actuator for positioning the nose member relative to the actuator; andwhereintranslation of the wedge member along the longitudinal axis of the implant displaces the upper body portion and the lower body portion away from each other, thereby expanding the intervertebral implant.Statement 25. The implant of statement 24, further comprising a frictional bearing providing a frictional force retarding movement of the upper body portion relative to the lower body portion.Statement 26. The implant of statement 24 and any statements after statement 24, further comprising an opening in at least one of the upper body portion and the lower body portion for a bone graft window.Statement 27. The implant of statement 24 and any statements after statement 24, wherein at least one of the upper body portion and the lower body portion comprises a corrugated surface.Statement 28. The implant of statement 24 and any statements after statement 24, wherein the actuator is threadably connected to the wedge member such that rotating the actuator translates the wedge member along toward the nose member.Statement 29. The implant of statement 24 and any statements after statement 24, wherein dovetails on the wedge member hold and slidably connect the upper body portion and the lower body portion to the wedge member.Statement 30. The implant of statement 24 and any statements after statement 24, wherein dovetail grooves on the nose member hold and slidably connect the upper body portion and the lower body portion to the nose member.Statement 31. The implant of statement 24 and any statements after statement 24, wherein a drive end of the actuator opposite the nose member is configured to connect with an insertion tool for insertion of the implant between vertebrae.Statement 32. The implant of statement 24 and any statements after statement 24, wherein a head of the actuator, opposite the wedge member, is located in the nose member.Statement 33. The implant of statement 24 and any statements after statement 24, whereinthe actuator by turning advances the wedge member toward the nose member to expand the implant, andthe actuator and the wedge member have respectively male and female threads to thereby advance the wedge member when the actuator is turned.Statement 34. The implant of statement 24 and any statements after statement 24, wherein the pin maintains a position of the nose member relative to the actuator once the implant has been assembled, the position being offset from a longitudinal axis of the wedge member.Statement 35. The implant of statement 24 and any statements after statement 24, wherein, on a posterior side of the implant, plural dovetail grooves in the nose member respectively hold and slidably connect the upper body portion and the lower body portion to the nose member.Statement 36. The implant of statement 35, wherein, on an anterior side of the implant, a common dovetail groove in the endplate holds and slidably connects the upper body portion and the lower body portion to the nose member.Statement 37. The implant of statement 24 and any statements after statement 24, whereina through-hole in the wedge member comprises a passageway for an insertion tool to connect to and turn the actuator.Statement 38. The implant of statement 24 and any statements after statement 24, whereinthe wedge member comprises a leading wedge, an intermediate wedge, and a trailing wedge connected together by a pair of rails, and the intermediate wedge comprises a pair of wedges with a gap in between.Statement 39. The implant of statement 24 and any statements after statement 24, wherein a posterior wedge of the pair of wedges is shorter in height than an anterior wedge of the pair of wedges, relative heights of the posterior wedge and the anterior wedge defining a lordotic angle tapering downward toward a posterior side of the implant.Statement 40. The implant of statement 39, wherein the anterior wedge has a) an upper half with a superior dovetail disposed outside the graft window and b) a lower half with an inferior dovetail disposed outside the graft window.Statement 41. The implant of statement 39, wherein the posterior wedge has a) an upper half with a superior dovetail disposed inside the graft window and b) a lower half with an inferior dovetail groove disposed outside the graft window.Statement 42. The implant of statement 41, wherein,in a collapsed state on a posterior side of the implant, an upper ramp extending downward from the upper body portion overlaps a lower ramp extending upward from the lower body portion, andan upper dovetail groove in the upper ramp on the posterior side engages the superior dovetail inside the graft window and a lower dovetail groove in the lower ramp on the posterior side engages the inferior dovetail that is disposed outside the graft window.Statement 43. The implant of statement 24 and any statements after statement 24, wherein, on an anterior side of the nose member, a dovetail groove comprises a slot to receive therein a head of the actuator.Statement 44. The implant of statement 24 and any statements after statement 24 wherein at least one of the upper body portion and the lower body portion has an asymmetric graft window with a larger opening to a first side of the implant extending along a length of the wedge member than to a second side of the implant opposite the first side.Statement 45. The implant of statement 24 and any statements after statement 24, wherein at least one of the upper body portion and the lower body portion has an asymmetric graft window with a larger opening to an anterior side of the implant than to a posterior side of the implant.Statement 46. An expandable intervertebral implant comprising:an upper body portion having an asymmetric graft window with a larger opening to an anterior side of the implant than to a posterior side of the implant;a lower body portion opposite the upper body portion;a wedge member connecting the upper body portion to the lower body portion, the wedge member comprises in order a first wedge, a second wedge, and a third wedge connected together by a rail, the second wedge comprising a posterior wedge and an anterior wedge separated from the posterior wedge, wherein the posterior wedge occludes the graft window on the posterior side of the implant;a nose member having a tapered distal end and a proximal end opposite the distal end, the nose member slidably connected to the upper body portion and the lower body portion;an actuator disposed between the nose member and the wedge member for translation of the wedge member along a longitudinal axis of the implant;the actuator on a first side slidably connected the nose member and on a second side connected to the wedge member;a pin connects to the actuator for positioning the nose member relative to the actuator; andwhereintranslation of the wedge member along the longitudinal axis of the implant displaces the upper body portion and the lower body portion away from each other, thereby expanding the intervertebral implant.Statement 47. The implant of statement 46, further comprising a frictional bearing providing a frictional force retarding movement of the upper body portion relative to the lower body portion.Statement 48. The implant of statement 46 and any statements after statement 46, further comprising an opening in at least one of the upper body portion and the lower body portion for a bone graft window.Statement 49. The implant of statement 46 and any statements after statement 46, wherein at least one of the upper body portion and the lower body portion comprises a corrugated surface.Statement 50. The implant of statement 46 and any statements after statement 46, wherein the actuator is threadably connected to the wedge member such that rotating the actuator translates the wedge member along toward the nose member.Statement 51. The implant of statement 46 and any statements after statement 46, wherein dovetails on the wedge member hold and slidably connect the upper body portion and the lower body portion to the wedge member.Statement 52. The implant of statement 46 and any statements after statement 46, wherein dovetail grooves on the nose member hold and slidably connect the upper body portion and the lower body portion to the nose member.Statement 53. The implant of statement 46 and any statements after statement 46, wherein a drive end of the actuator opposite the nose member is configured to connect with an insertion tool for insertion of the implant between vertebrae.Statement 54. The implant of statement 46 and any statements after statement 46, wherein a head of the actuator, opposite the wedge member, is located in the nose member.Statement 55. The implant of statement 46 and any statements after statement 46, whereinthe actuator by turning advances the wedge member toward the nose member to expand the implant, andthe actuator and the wedge member have respectively male and female threads to thereby advance the wedge member when the actuator is turned.Statement 56. The implant of statement 46 and any statements after statement 46, wherein the pin maintains a position of the nose member relative to the actuator once the implant has been assembled, the position being offset from a longitudinal axis of the wedge member.Statement 57. The implant of statement 46 and any statements after statement 46, wherein, on a posterior side of the implant, plural dovetail grooves in the nose member respectively hold and slidably connect the upper body portion and the lower body portion to the nose member.Statement 58. The implant of statement 57, wherein, on an anterior side of the implant, a common dovetail groove in the endplate holds and slidably connects the upper body portion and the lower body portion to the nose member.Statement 59. The implant of statement 46 and any statements after statement 46, whereina through-hole in the wedge member comprises a passageway for an insertion tool to connect to and turn the actuator.Statement 60. The implant of statement 46 and any statements after statement 46, whereinthe second wedge comprises a pair of wedges with a gap in between.Statement 61. The implant of statement 46 and any statements after statement 46, wherein relative heights of the posterior wedge and the anterior wedge define a lordotic angle tapering downward toward a posterior side of the implant.Statement 62. The implant of statement 46 and any statements after statement 46, wherein the anterior wedge has a) an upper half with a superior dovetail disposed outside the graft window and b) a lower half with an inferior dovetail disposed outside the graft window.Statement 63. The implant of statement 46 and any statements after statement 46, wherein the posterior wedge has a) an upper half with a superior dovetail disposed inside the graft window and b) a lower half with an inferior dovetail groove disposed outside the graft window.Statement 64. The implant of statement 63, wherein,in a collapsed state on a posterior side of the implant, an upper ramp extending downward from the upper body portion overlaps a lower ramp extending upward from the lower body portion, andan upper dovetail groove in the upper ramp on the posterior side engages the superior dovetail inside the graft window and a lower dovetail groove in the lower ramp on the posterior side engages the inferior dovetail that is disposed outside the graft window.Statement 65. The implant of statement 46 and any statements after statement 46, wherein, on an anterior side of the nose member, a dovetail groove comprises a slot to receive therein a head of the actuator.Statement 66. An expandable intervertebral implant comprising:an upper body portion having an asymmetric graft window with a larger opening to an anterior side of the implant than to a posterior side of the implant;a lower body portion opposite the upper body portion;a wedge member connecting the upper body portion to the lower body portion,a nose member having a tapered distal end and a proximal end opposite the distal end, the nose member slidably connected to the upper body portion and the lower body portion;an actuator disposed between the nose member and the wedge member for translation of the wedge member along a longitudinal axis of the implant;the actuator on a first side slidably connected the nose member and on a second side connected to the wedge member;a pin connects to the actuator for positioning the nose member relative to the actuator; andwhereintranslation of the wedge member along the longitudinal axis of the implant displaces the upper body portion and the lower body portion away from each other, thereby expanding the intervertebral implant.

Numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.