(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2008/0015701 A1
`(43) Pub. Date:
`Jan. 17, 2008
`Garcia et al.
`
`US 200800 15701A1
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`(54)
`(76)
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`(21)
`(22)
`
`(62)
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`SPINAL IMPLANT
`
`Inventors: Javier Garcia, (US); Erik J. Wagner,
`Austin, TX (US); David J. Krueger,
`Cedar Park, TX (US)
`Correspondence Address:
`ROBERT DEBERARDINE
`ABBOTT LABORATORIES
`1OO ABBOTT PARK ROAD
`DEPT. 377AAP6A
`ABBOTT PARK, IL 60064-6008 (US)
`Appl. No.:
`11/774,406
`
`Filed:
`
`Jul. 6, 2007
`
`Related U.S. Application Data
`Division of application No. 10/291,245, filed on Nov.
`8, 2002, now abandoned.
`
`(60) Provisional application No. 60/338,321, filed on Nov.
`9, 2001.
`
`Publication Classification
`
`(51) Int. Cl.
`(2006.01)
`A6B 7/58
`(2006.01)
`A6IF 2/44
`(52) U.S. Cl. ...................... 623/17.16; 606/99; 623/17.11
`
`(57)
`
`ABSTRACT
`
`A spinal implant may be made of two or more implant
`members. In an embodiment, implant members may be
`joined together by a rotational connection that inhibits
`separation of the members as well as axial movement of the
`members relative to each other. Implant members may be
`coupled together by a pin or pins, adhesive, or other fasten
`ers to inhibit separation and/or rotation of the members
`relative to each other.
`
`
`
`NUVASIVE - EXHIBIT 2007
`Alphatec Holdings Inc. et al. v. NuVasive, Inc.
`IPR2019-00362
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`SPINAL MPLANT
`
`PRIORITY CLAIM
`0001. This application claims priority to U.S. Provisional
`Application No. 60/338,321 entitled “Spinal Implant”, filed
`Nov. 9, 2001. The above-referenced provisional application
`is incorporated by reference as if fully set forth herein.
`
`BACKGROUND OF THE INVENTION
`
`0002)
`1. Field of the Invention
`0003. The present invention generally relates to the field
`of bone implants and more particularly to spinal implants.
`Spinal implant embodiments may stabilize and/or fuse
`together vertebrae. Some spinal implant embodiments may
`be inserted during a posterior lumbar interbody fusion
`procedure.
`0004 2. Description of Related Art
`0005. An intervertebral disc may degenerate. Degenera
`tion may be caused by trauma, disease, and/or aging. An
`intervertebral disc that becomes degenerated may have to be
`partially or fully removed from a spinal column. Partial or
`full removal of an intervertebral disc may destabilize the
`spinal column. Destabilization of a spinal column may result
`in alteration of a natural separation distance between adja
`cent vertebrae. Maintaining the natural separation between
`vertebrae may prevent pressure from being applied to nerves
`that pass between vertebral bodies. Excessive pressure
`applied to the nerves may cause pain and/or nerve damage.
`During a spinal fixation procedure, a spinal implant may be
`inserted within a space created by the removal or partial
`removal of an intervertebral disc between adjacent verte
`brae. The spinal implant may maintain the height of the
`spine and restore stability to the spine. Bone growth may
`fuse the implant to adjacent vertebrae.
`0006 A spinal implant may be inserted during a spinal
`fixation procedure using an anterior, lateral, or posterior
`spinal approach. A discectomy may be performed to remove
`or partially remove a defective or damaged intervertebral
`disc. The discectomy creates a disc space for a spinal
`implant. The amount of removed disc material may corre
`spond to the size and type of spinal implant to be inserted.
`0007 Spinal surgery may be complex due in part to the
`proximity of the spinal cord and/or the cauda equina. Prepa
`ration instruments and spinal implants may need to be
`carefully inserted to avoid damage to nerve tissue. Align
`ment and spacing of a spinal implant that is to be inserted
`into a patient may be determined before Surgery. Achieving
`the predetermined alignment and spacing during Surgery
`may be important to achieve optimal fusion of adjacent
`vertebrae.
`0008 Bone graft and/or bone implants may be used to
`promote bone growth that will fuse vertebrae together. Bone
`graft may be autogenic bone, allogenic bone, synthetic
`material, Xenogenic bone or combinations thereof. Autoge
`nic bone is bone obtained from another location of a patient.
`Allogenic bone is bone derived from the same species as the
`patient. Xenogenic bone is bone derived from a species other
`than that of the patient. Implants may be formed of metal,
`polymers, ceramics, autogenic bone, allogenic bone, Xeno
`genic bone, or combinations thereof
`
`0009 U.S. Pat. No. 5,814,084 to Grivas et al., which is
`incorporated by reference as if fully set forth herein,
`describes diaphysial cortical bone dowels. The dowels are
`obtained from transverse plugs across the diaphysis of long,
`bones. The natural intramedullary canal of the source bone
`may form a cavity through the dowel perpendicular to the
`length of the dowel.
`0010 U.S. Pat. No. 6,025,538 to Yaccarino, III, which is
`incorporated by reference as if fully set forth herein,
`describes a composite allograft bone device. A first bone
`component is formed with a plurality of grooves. A second
`bone component is formed with a plurality of protrusions
`that mate with the grooves of the first bone component. A pin
`positioned at an oblique angle through the bone components
`joins the components together to form the composite
`allograft bone device.
`0011 U.S. Pat. No. 6,143,033 to Paul et al., which is
`incorporated by reference as if fully set forth herein,
`describes an allogenic intervertebral implant. The interver
`tebral implant is an annular plug that conforms in size and
`shape to end plates of adjacent vertebrae. Top and bottom
`Surfaces of the implant have teeth to resist expulsion and to
`provide initial stability.
`
`SUMMARY OF THE INVENTION
`0012. A spinal implant may be used to provide stability
`and promote fusion of adjacent vertebrae. The implant may
`be used in conjunction with a spinal stabilization device
`Such as a bone plate or rod-and-fastener stabilization system.
`The implant may be formed of two or more pieces that are
`attached together. The implant may establish a desired
`separation distance between vertebrae. The implant may
`promote bone growth between adjacent vertebrae that fuses
`the vertebrae together.
`0013 In some implant embodiments, the implants may
`be made of bone. In some embodiments, bone pieces that
`form the implant may include rotational dovetails so that a
`dovetail joint is formed when the pieces are connected
`together. The dovetail joint may inhibit separation of the
`bone pieces. The dovetail joint may inhibit lateral movement
`of the bone pieces relative to each other. A pin may be used
`to join the pieces together to inhibit rotation of the pieces
`relative to each other.
`0014. In some implant embodiments, a first implant piece
`may include a protrusion. A second implant piece may
`include a complementary groove. The pieces may be joined
`in an interlocking engagement to align the pieces and inhibit
`axial movement of the pieces relative to each other. A
`fastener may be placed into openings in the pieces to join the
`so pieces together and form the implant. The fastener may
`inhibit movement of the pieces relative to each other. The
`use of a protrusion on a first implant piece and a groove on
`a second implant piece may simplify manufacturing proce
`dures and time needed for forming spinal implants. Simpli
`fied manufacturing procedures may reduce manufacturing
`errors that result in loss of useable bone.
`0015. In some implant embodiments, implants may be
`formed of three or more pieces. Two pieces are outer pieces
`that have Surfaces for contacting vertebrae during use. Other
`pieces are middle pieces that allow an implant of a desired
`height to be formed. Mating surfaces of two pieces that are
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`to be joined together may include a single protrusion and a
`single groove. After the pieces are joined together and
`aligned, a fastener may be placed into openings to join the
`pieces together and form the implant. In some implant
`embodiments, more than one fastener may be used to join
`implant pieces together.
`0016 Openings in implant pieces for a fastener that joins
`implant pieces together may be formed so that an axis of the
`opening is Substantially normal to an interface between
`implant pieces (e.g., within about +4° of being at 90°), Using
`openings that are normal to the interface between implant
`pieces may simplify formation of the openings and reduce
`useable bone loss due to fracturing of bone pieces caused by
`forming angulated openings.
`0017. In some implant embodiments, fasteners that join
`implant pieces together are dowels that are press fit into
`openings in the implant pieces. In other embodiments,
`fasteners may be, but are not limited to, Screws, Snap-locks,
`or barbs. In some embodiments, implant pieces may be
`joined together by adhesive and/or press fit connections.
`0018. In an implant embodiment, the implant includes
`channels along sides of the implant. An implant inserter may
`grasp the channels to allow for insertion of the implant into
`a prepared disc space. The implant channels provide a large
`Surface area for contact between the implant and the implant
`inserter. The implant channels may be deep enough so that
`outer Surfaces of the implant inserter adjacent to the implant
`are slightly recessed relative to side surfaces of the implant
`when the implant inserter holds the implant. The arrange
`ment of the implant inserter relative to the implant allows for
`an opening between bones that are to be fused together by
`the implant to be formed to a width that is substantially the
`same as the width of the implant.
`0019. Implants may be constructed of any biocompatible
`materials sufficiently strong to maintain spinal distraction.
`Implants may be, but are not limited to, allograft bone,
`Xenograft bone, autograft bone, metals, ceramics, polymers,
`or combinations thereof. 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. The treatment
`may be, but is not limited to, applying a hydroxyapatite
`coating on contact surfaces, providing a titanium plasma
`spray on contact surfaces, or texturing the contact Surfaces
`by scoring, peening, implanting particles in the Surfaces, or
`otherwise roughening the Surfaces.
`0020. In some embodiments, the implant may include an
`opening that extends through a height of the implant. The
`opening may have a regular shape or an irregular shape.
`Bone graft may be placed in the opening. The bone graft
`may be autogenic bone graft, allogenic bone graft, Xeno
`genic bone graft, and/or synthetic bone graft.
`0021. Some implant embodiments may be constructed
`from allogenic bone. Such as cortical bone from a femur,
`tibia, or other large bone. In some embodiments, an implant
`may be formed from a single piece of allograft bone that is
`cut to a desired shape.
`0022 Desired dimensions of a bone implant may exceed
`the dimensions of an implant that may be formed using a
`single piece of available bone. Two or more pieces of bone
`may be used to form an implant of a desired length, width,
`and height. Using pieces of bone may allow for efficient use
`
`of available bone. Using pieces of bone may allow for
`formation of an implant that has greater strength than an
`implant formed of a single piece of bone.
`0023 Bone pieces that are used to form an implant may
`be formed with joints. The joints may be male or female
`dovetail joints. The joints may be rotational joints that
`connect with a mating joint when the pieces are rotated
`relative to each other. The joints may hold the pieces
`together and inhibit axial displacement of the pieces relative
`to each other. A fastener may couple the pieces together to
`inhibit axial and/or rotational movement of the pieces rela
`tive to each other.
`0024. In some embodiments, bone pieces that are joined
`together to form an implant are processed in a frozen state.
`Care may need to be taken during thawing of the implant to
`ensure that a fastener or fasteners of the implant remain
`securely connected to the implant. In some embodiments,
`bone pieces that are joined together to form an implant are
`processed in a freeze-dried State. Using bone in a freeze
`dried State advantageously allows all pieces of resulting
`implant to remain securely connected together when the
`implant is reconstituted before insertion into a patient.
`0025 To forman implant from implant pieces, upper and
`lower surfaces of individual pieces may be machined to have
`desired maximum lengths, widths, and heights. Sides of the
`pieces may be machined so that the assembled implant will
`have side implant channels when assembled. An appropriate
`joint may be formed in a surface of the implant piece that
`will mate with another implant piece. In some implant
`embodiments, openings are formed in the implant pieces.
`The openings may be formed so that an axis of the opening
`is Substantially normal to a Surface of the implant piece that
`will mate to another implant piece. The individual pieces are
`joined together. A fastener is used to join the pieces together.
`0026.
`After the pieces are joined together, the implant
`may be machined to form teeth in surfaces of the implant
`that contact vertebrae. Also, the implant may be machined so
`that an anterior height of the implant is different than a
`posterior height of the implant. An implant with different
`anterior and posterior heights may allow the implant to
`establish a desired lordotic angle between adjacent verte
`brae.
`0027. Instruments may be used to prepare a space for an
`implant. An instrument may be used to insert an implant in
`a prepared space. Instruments may be supplied to a Surgeon
`or Surgical team in an instrument set. The instrument set may
`also include one or more implants that can be inserted into
`a patient during an insertion procedure. Implant may be
`provided in various sizes and with various lordotic angles so
`that the implant or implants installed in the patient suit the
`needs of the patient.
`0028. An instrumentation set may include distractors. In
`Some embodiments, the distractors may be fixed tip distrac
`tors. In some embodiments, the distractors may be modular
`tip distractors. A shaft and a handle may be removed from
`a modular tip distractor to leave only the modular tip
`distractor in a disc space. Leaving only a modular tip
`distractor in a disc space may create more room for visual
`ization and maneuverability during an implant insertion
`procedure.
`0029. An instrumentation set may include a chisel. The
`chisel may form grooves in vertebral Surfaces. The grooves
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`may be sized to accept a portion of an implant that is to fuse
`vertebrae together. The chisel may simultaneously form
`channels in both vertebra during use.
`0030. An instrumentation set may include an implant
`inserter. The implant inserter may grasp side walls of an
`implant. Grasping side walls of the implant may allow for
`removal of the implant inserter from the implant inserter
`without the application of significant rotational forces to the
`implant. The implant inserter may have a low profile that
`allows for visualization of the implant and Surrounding area
`during insertion of the implant
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`0031 Advantages of the present invention will become
`apparent to those skilled in the art with the benefit of the
`following detailed description of embodiments and upon
`reference to the accompanying drawings in which:
`0032 FIG. 1 depicts a perspective representation of an
`embodiment of an implant.
`0033 FIG. 2 depicts a plan view of an embodiment of an
`implant member that emphasizes a Surface of the implant
`member having a male joint.
`0034 FIG. 3 depicts a cross-sectional representation of
`an embodiment of an implant member that has a male joint
`taken substantially along line 3-3 of FIG. 2.
`0035 FIG. 4 depicts a cross-sectional representation of
`an embodiment of an implant member that has a female
`joint.
`FIG. 5 depicts an embodiment of an implant
`0.036
`formed of three implant members.
`0037 FIG. 6 depicts an embodiment of an implant that
`includes a passage through the implant.
`0038 FIG. 7 depicts a perspective view of an embodi
`ment of a single-member implant.
`0.039
`FIG. 8 depicts a cross-sectional representation of a
`single-member implant.
`0040 FIG.9 depicts a front view of an embodiment of an
`implant.
`FIG. 10 depicts a front view of an embodiment of
`0041
`an implant.
`0.042
`FIG. 11 depicts a front view of an embodiment of
`an implant.
`0.043
`FIG. 12 depicts a perspective exploded view of
`components of an embodiment of an implant formed of two
`implant members.
`0044 FIG. 13 depicts a perspective exploded view of
`components of an embodiment of an implant formed of three
`implant members.
`0045 FIG. 14 depicts a perspective view of an embodi
`ment of a fixed tip distractor.
`0046 FIG. 15 depicts a perspective view of an embodi
`ment of a modular tip distractor.
`0047 FIG. 16 depicts a perspective view of an embodi
`ment of a modular tip of a modular tip distractor.
`
`0048 FIG. 17 depicts a perspective view of an embodi
`ment of an end portion of a shaft for a modular tip distractor
`when the shaft is in an unreleased position.
`0049 FIG. 18 depicts a perspective view of an embodi
`ment of an end portion of a shaft for a modular tip distractor
`when the shaft is in a released position.
`0050 FIG. 19 depicts a representation of an embodiment
`of a modular tip distractor inserted in a disc space prior to
`distraction of vertebrae.
`0051
`FIG. 20 depicts a representation of an embodiment
`of a modular tip distractor inserted in a disc space after
`distraction of vertebrae.
`0052 FIG. 21 depicts a representation of an embodiment
`of a modular tip inserted in a disc space after removal of a
`shaft from the modular tip.
`0053 FIG. 22 depicts a perspective view of an embodi
`ment of a chisel for preparing bone for implant insertion.
`0054 FIG. 23 depicts a perspective view of an embodi
`ment of a chisel for preparing bone for implant insertion.
`0.055
`FIG. 24 depicts a front view of a portion of an
`embodiment of a chisel, including an inset view that shows
`a chisel blade relative to a chisel guide.
`0056 FIG. 25 depicts an embodiment of a slap hammer.
`0057 FIG. 26 depicts an embodiment of an implant
`inserter.
`0058 FIG. 27 depicts an embodiment of an implant
`inserter.
`0059 While the invention is susceptible to various modi
`fications and alternative forms, specific embodiments
`thereof are shown by way of example in the drawings and
`will herein be described in detail. The drawings may not be
`to scale. It should be understood, however, that the drawings
`and detailed description thereto are not intended to limit the
`invention to the particular form disclosed, but to the con
`trary, the intention is to cover all modifications, equivalents,
`and alternatives falling within the spirit and scope of the
`present invention as defined by the appended claims.
`
`DETAILED DESCRIPTION OF EMBODIMENTS
`0060 FIGS. 1-13 show embodiments of implants 40 and
`portions of implants that may be used to promote bone
`fusion. Implants 40 may be spinal implants, such as, but not
`limited to, posterior lumbar interbody fusion (PLIF) spinal
`implants. A spinal implant may establish a desired separa
`tion distance between adjacent vertebrae. In some implant
`embodiments, implants have surfaces made of bone or bone
`growth promoting material (e.g., hydroxyapatite or titanium
`plasma spray) that promotes fusion of the implants to
`vertebrae. In some embodiments, implants may include
`openings. The openings may be packed with bone graft or
`other bone growth material that promotes bone growth from
`vertebrae into the implant to fuse the implant to the verte
`brae.
`0061 As depicted in FIG. 1, implant 40 may include
`members 42, fastener 44, side grooves 46, and serrations or
`ridges 48. An implant may include two or more members 42.
`Members 42 may be joined together to form implant 40. In
`Some embodiments, members 42 may be joined together by
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`a rotational dovetail joint. The rotational dovetail joint may
`inhibit separation and axial movement of members 42
`relative to each other. Fastener 44 may be press fit into an
`opening that extends through first member 42 and into an
`opening in second member 42". In some embodiments,
`fastener 44 may inhibit rotation of first member 42 relative
`to second member 42".
`0062. In some embodiments, a joint of the first member
`may allow the first member to fully rotate (i.e., through
`360°) in a clockwise or counterclockwise direction when
`coupled to a corresponding mating joint in the second
`member. In some embodiments, a range of motion and/or a
`direction of motion may be limited. For example, in an
`embodiment, a joint of the first member can be rotated 45°
`in a clockwise direction when coupled to a corresponding
`mating joint of a second member. Surface contact between
`the first member and the second member inhibits rotational
`movement beyond the 45° limit. Surface contact between
`the first member and the second member inhibits initial
`counterclockwise rotation of the first member relative to the
`second member. Other embodiments may have different
`angular rotation limits (e.g., 30° or 60') or other angular
`direction limits. In some embodiments, a first member may
`rotate relative to the second member for only a limited range
`of angular rotation in either a clockwise or a counterclock
`wise direction.
`0063 FIG. 2 depicts a plan view of an embodiment of
`member 42 that emphasizes a surface of the member that
`has male dovetail 50. Male dovetail 50 may include arced
`surfaces 52. Arced surfaces 52 may be, circular arcs that are
`concentric. FIG. 3 depicts a cross-sectional view of an
`embodiment of member 42 having male dovetail 50.
`0064 FIG. 4 depicts a cross-sectional view of member
`42" that has female dovetail 54. Female dovetail 54 may
`include arced surfaces 56. Arced surfaces 56 may be circular
`arcs that have are concentric.
`0065. Male dovetail 50 of member 42 (shown in FIG. 3)
`may be placed in female dovetail 54 of member 42" (shown
`in FIG. 4), with a long axis of member 42 oriented sub
`stantially perpendicular to a long axis of member 42".
`Member 42 may be rotated to a position substantially
`parallel to member 42". When members 42", 42" are properly
`oriented, openings 58 in the members may align with each
`other. Fastener 44, depicted in FIGS. 1 and 5, may be placed
`into openings 58 to inhibit further rotation of member 42
`relative to member 42". Openings 58 may be formed in
`members 42", 42" before or after the members are joined
`together using female dovetail 54 and male dovetail 50 of
`the members. In some embodiments, an opening in a mem
`ber may be a blind opening (i.e., an opening that does not
`extend completely through the member).
`0066.
`In some embodiments, fastener 44 may be press fit
`into openings in members 42 to join the members together
`to form implant 40, as depicted in FIGS. 5 and 6. In other
`embodiments, the fastener may be another type of fastener,
`including, but not limited to, a screw, a Snap lock connector,
`a barbed connector, and/or adhesive. The fastener may be
`made of the same material as the implant members (e.g.,
`bone). In other embodiments, the fastener may be made of
`a different material than the implant members. The fastener
`or a portion of the fastener may include material that
`promotes osseointegration of the fastener and the implant
`
`with vertebrae. The fastener or a portion of the fastener may
`be made of a material that is absorbable in the body of a
`patient. After absorption, bone may grow in place of the
`bioabsorbable material to facilitate fusion of the implant to
`bone of a patient.
`0067. In some embodiments, an implant may be formed
`of three or more members. FIG. 5 depicts an embodiment of
`implant 40 formed of three members 42. In some embodi
`ments, four, five, or more members may be joined together
`to form an implant. An implant formed from two or more
`members may have a larger height than an implant formed
`from a single piece of bone. The ability to form an implant
`from two or more members may allow for the formation of
`an implant of a desired height while maximizing the use of
`available donor bone.
`0068 Rotational dovetail joints may connect members
`together. Male and female joints may be formed in pieces
`that form the implant. For example, in an embodiment of a
`three-member implant, male joints are formed in outer
`members of the implant, and an interior member is formed
`with two female joints. In another embodiment of a three
`member implant, an interior member is formed with a male
`joint and a female joint, one of the outer members has a male
`joint, and the other outer member has a female joint. In
`another embodiment of a three-member implant, female
`joints are formed in outer members, and an interior member
`is formed with two male joints.
`0069. In some implant embodiments, an implant may
`have a passage or passages from one side of the implant to
`an opposite side of the implant. FIG. 6 depicts implant 40
`that includes passage 60 through the implant. Passage 60
`may be formed in members 42 before or after the members
`are joined together. Passage 60 may have any desired
`cross-sectional shape. The passage cross-sectional shape
`may be, but is not limited to, circular, oval, square, rectan
`gular, or irregular. Bone growth material (e.g., autogenic
`bone graft, allogenic bone graft, Xenogenic bone graft, or
`synthetic bone graft) may be placed in the passage or
`passages to facilitate spinal fusion.
`0070. In some implant embodiments, bone may be used
`to form an implant. Portions of the bone used to form the
`implant may be cortical bone. The cortical bone may provide
`strength to the implant. In some implant embodiments, the
`bone used to form an implant may be processed in a frozen
`state. In some implant embodiments, bone used to form an
`implant may be processed in a freeze-dried State.
`0071. In some implant embodiments, the implant and/or
`outer surfaces of the implant that contact a vertebra may be
`made of a material other than bone. The surface that contacts
`the vertebra may be treated to enhance osseointegration of
`the implant with the vertebra. The surface may include
`protrusions that extend into the vertebra. The surface may
`include a hydroxyapatite coating, a titanium plasma spray
`coating, and/or, texturing. Texturing may be used to modify
`the Surface of an implant to reduce expulsion and provide
`stability. Texturing may be provided by many different
`methods, such as, but not limited to, Sanding the Surface,
`forming grooves within the Surface, shot peening the Sur
`face, scoring the Surface using an electrical discharge pro
`cess, and/or embedding hard particles within the Surface.
`Texturing may also be formed in outer Surfaces of implants
`formed of bone.
`
`

`

`US 2008/OO15701 A1
`
`Jan. 17, 2008
`
`0072 Implants may be constructed of biocompatible
`material Sufficiently strong to maintain bone separation.
`Implant members and/or fasteners may be made of bone or
`of other material. Such as metals, ceramics, polymers, or
`combinations thereof. Bone used to form an implant may be
`allogenic bone or Xenogenic bone. In some embodiments, a
`portion or portions of an implant may be autogenic bone. In
`Some embodiments, bone, or portions of bone, used to form
`an implant may be demineralized. An implant, or a portion
`of an implant, may be made of a bioabsorbable material. For
`example, portions of an implant may be made of a polyan
`hydride, an alpha polyester, and/or a polylactic acid-polyg
`lycolic acid copolymer.
`0073. In some embodiments, an implant may be a single
`member implant constructed from bar stock or formed from
`moldable material of suitable strength to withstand pressure
`within a normal human spine. For example, a single-member
`implant may be constructed from metals including, but not
`limited to, titanium, titanium alloys, and medical grade
`stainless steel. A single-member implant may be molded or
`cut from materials including, but not limited to, polyether
`ether ketone (PEEK), carbon fiber reinforced PEEK, and
`other polymers.
`0074 FIG. 7 depicts an embodiment of single-member
`implant 40. Implant 40 may include indicia 62. Indicia 62
`may identify size, shape, and/or, orientation of implant 40.
`Implant 40 may include one or more passages 60 and/or one
`or more passages 64. In an embodiment, passage 64 may be
`Substantially perpendicular to passage 60. Passages 60. 64
`may have any desired cross-sectional shape. Cross-sectional
`shapes of passages 60, 64 may be, but are not limited to,
`circular, oval, square, rectangular, and/or irregular. Bone
`growth material (e.g., autogenic bone graft, allogenic bone
`graft, Xenogenic bone craft, or synthetic bone graft) may be
`placed in the passage or passages to facilitate spinal fusion.
`0075. In some embodiments, passages 60, 64 may be
`positioned at locations to promote overall strength of
`implant 40. In some embodiments, rib 66 may separate a first
`passage 60 from a second passage 60 and/or a first passage
`64 from a second passage 64. Rib 66 may provide strength
`to implant 40 such that a shape of the implant is maintained
`under pressure exerted by spinal compression. In an embodi
`ment, a single-member implant formed from PEEK may
`include at least one Supporting rib 66. In some embodiments,
`the use of rib 66 with proper placement of passages 60, 64
`may allow the use of virgin PEEK, as opposed to PEEK that
`includes carbon fiber or other type of reinforcement mate
`rial.
`In some cases, X-rays may be used to monitor
`0076.
`spinal fusion in a patient. Some implant embodiments (e.g.,
`PEEK implants) are substantially transparent to X-rays.
`X-ray detection of implant 40 formed of X-ray transparent
`material may be facilitated by including X-ray sensitive
`material in the implant. FIG. 8 depicts a cross-sectional
`representation of single-member implant 40 with openings
`68 for X-ray sensitive material. For example, tantalum wire
`(e.g., 1 mm in length) may be inserted into one or more
`openings 68 of implant 40 before implantation. In some
`embodiments, X-ray sensitive material may be located near
`an anterior end of the implant adjacent to a caudal (or,
`cephalic) Surface of the implant. X-ray sensitive material
`may also be located near a posterior end of the implant
`
`adjacent to a cephalic (or caudal) Surface of the implant. The
`use of X-ray sensitive material near anterior/posterior and
`caudal/cephalic Surfaces may allow the position of an
`implant to be visualized using X-ray imaging.
`0077 Bo