US007867277B1
`
`(12) United States Patent
`Tohmeh
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 7,867,277 B1
`Jan. 11, 2011
`
`(54) SPINAL FUSION IMPLANT AND RELATED
`METHODS
`
`(75) Inventor: Antoine G. Tohmeh, Spokane, WA (US)
`
`(73) Assignee: Nuvasive Inc., San Diego, CA (US)
`c
`- r
`(*) Notice:
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 296 days.
`(21) Appl. No.: 11/488,744
`
`(22) Filed:
`
`Jul. 17, 2006
`O
`O
`Related U.S. Application Dat
`pplication Uata
`e
`(60) Provisional application No. 60/699,597, filed on Jul.
`15, 2005.
`
`(51) Int. Cl.
`(2006.01)
`A6 IF 2/44
`(52) U.S. Cl. ................................................... 623A17.11
`(58) Field of Classification Search ................... 606/61;
`623/17.11 17.16
`See application file for complete search history.
`References Cited
`U.S. PATENT DOCUMENTS
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`(56)
`
`... 623, 17.11
`4,834,757 A * 5/1989 Brantigan ...
`... 623, 17.11
`4,878,915 A * 1 1/1989 Brantigan ...
`... 623, 17.11
`5.425,772 A * 6/1995 Brantigan ....
`5,443,514 A * 8/1995 Steffee ....................... 128/898
`5,814,084 A * 9/1998 Grivas et al. ............. 623.23.48
`5,861,041 A *
`1/1999 Tienboon ................. 623, 17.16
`6,033,438 A * 3/2000 Bianchi et al. ..
`... 623, 17.16
`6,241,770 B1* 6/2001 Michelson ............... 623, 17.11
`
`
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`6,402,785 B1* 6/2002 Zdeblicket al. .......... 623, 17.16
`6,485,517 B1 * 1 1/2002 Michelson ........
`... 623, 17.11
`6,537,320 B1* 3/2003 Michelson .....
`... 623, 17.11
`6,666,890 B2 * 12/2003 Michelson .....
`... 623, 17.11
`6,942,697 B2 * 9/2005 Lange et al. ...
`... 623.17.11
`7,022,137 B2 * 4/2006 Michelson .....
`... 623, 17.11
`7,156,875 B2* 1/2007 Michelson .....
`... 623, 17.11
`7,455,692 B2 * 1 1/2008 Michelson .....
`... 623, 17.11
`2001/0020186 A1* 9/2001 Boyce et al. ............. 623/17.16
`2005/0143822 A1* 6/2005 Paul .................
`... 623, 17.16
`2005/0216082 A1* 9, 2005 Wilson et al. ............ 623, 17.11
`2009/0105821 A1* 4/2009 Michelson ............... 623, 17.11
`* cited by examiner
`Primary Examiner Eduardo C Robert
`Assistant Examiner Mary Hoffman
`(74) Attorney, Agent, or Firm Nuvasive Inc.; Jonathan
`Spangler
`
`(57)
`
`ABSTRACT
`
`A spinal fusion implant of non-bone construction to be intro
`duced into any variety of spinal target sites. The spinal fusion
`implant of the present invention includes a top surface, a
`p
`p
`p
`bottom Surface, first and second lateral sides, a proximal
`(posterior) end and a distal (anterior) end. The spinal fusion
`implant of the present invention may be used to provide
`temporary or permanent fixation within an orthopedic target
`site. To do so, the spinal fusion implant may be introduced
`into a disc space while locked to a Surgical insertion instru
`ment and thereafter employed in the proper orientation and
`released. Once deposited in the disc space, the spinal fusion
`implant of the present invention effects spinal fusion over
`time as the natural healing process integrates and binds the
`implant.
`
`19 Claims, 9 Drawing Sheets
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`Exhibit 1034
`LIFE SPINE, INC.
`IPR2022-01602
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`000001
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`1.
`SPINAL FUSION MPLANT AND RELATED
`METHODS
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`US 7,867,277 B1
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`CROSS REFERENCES TO RELATED
`APPLICATIONS
`
`The present application is a nonprovisional patent applica
`tion claiming benefit under 35 U.S.C. S 119(e) from U.S.
`Provisional Application Ser. No. 60/699,597, filed on Jul. 15,
`2005, the entire contents of which are hereby expressly incor
`porated by reference into this disclosure as if set forth fully
`herein.
`
`BACKGROUND OF THE INVENTION
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`I. Field of the Invention
`The present invention relates generally to spinal Surgery
`and, more particularly, to a device for spinal fusion compris
`ing a spinal fusion implant of non-bone construction to be
`introduced into any variety of spinal target sites.
`II. Discussion of the Prior Art
`Currently there are nearly 500,000 lumbar and cervical
`spinal fusion procedures performed each year in the United
`States. One of the causes of back pain and disability derives
`from the rupture or degeneration of one or more intervertebral
`discs in the spine. Surgical procedures are commonly per
`formed to correct problems with displaced, damaged, or
`degenerated intervertebral discs due to trauma, disease, or
`aging. Generally, spinal fusion procedures involve removing
`Some or the all of the diseased or damaged disc, and inserting
`one or more intervertebral implants into the resulting disc
`Space.
`Minimally invasive methods of performing spinal fusion
`have gained popularity in recent years due to the many ben
`efits of the procedure which include diminished dissection of
`body tissue and lower blood loss during Surgery resulting in
`reduced Surgery time, lower post-operative pain and a quicker
`recovery for patients. Transforaminal lumbar interbody
`fusion (TLIF) procedures provide unilateral access to a
`desired target site. The TLIF technique involves approaching
`the spine in a similar manner as a posterior approach but more
`from the left or right of the spine through a midline incision in
`a patient’s back. This procedure requires only one incision in
`the back of a patient and involves placing a fusion device into
`the intervertebral disc space. Introducing the intervertebral
`implant serves to restore the height between adjacent verte
`brae (“disc height'), which reduces if not eliminates neural
`impingement commonly associated with a damaged or dis
`eased disc. Distraction of the disc space with Subsequent
`decompression of nerve roots can be accomplished by rotat
`ing a device between the adjacent vertebrae.
`Current spinal fusion implants utilize either bone grafts or
`artificial implants to fill the intervertebral disc space. Artifi
`cial implants may be made of metal, plastic composites,
`ceramics, bone, or any combination thereof. Natural bone
`grafts have also been developed including autologous and
`allograft bone. Other bone grafts may include certain man
`made Substances including binder joining bone chips and
`composite bone structures.
`While generally effective, the use of bone grafts presents
`several disadvantages. Autologous bone grafts are obtained
`from bone material surgically removed from the iliac crest of
`a patient. This method can be detrimental because it may not
`yield a sufficient quantity of graft material, requires addi
`tional Surgery, and increases the risk of infection and blood
`loss. Moreover, the structural integrity at the donor site can be
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`reduced and significant morbidity associated with harvesting
`the autologous bone graft may occur.
`Allograft bone is obtained from cadaveric specimens,
`machined, and sterilized for implantation. Production of
`allograft bone implants may be difficult because of the inher
`ent challenges in forecasting the receipt of cadavers. Further
`more, allograft may only provide temporary Support as it is
`difficult to manufacture the allograft with consistent shape
`and strength given the differing characteristics of cadavers.
`Graft material usually has a smooth surface which does not
`provide good friction between the adjacent vertebrae and
`slippage of the graft may occur which can cause neural and
`vascular injury as well as collapse of the disc space.
`A need remains for fusion implants that preserve the intra
`discal space and Support the vertebral column until the adja
`cent vertebrae are fused and still encourage bone ingrowth to
`achieve a solid fusion. A need also remains for implants
`which maximize cortical ring contact (both anteriorly and
`posteriorly), better facilitate self distraction of the vertebrae
`during insertion, avoid dural impingement and provide a bet
`ter fit between anterior edge portions of vertebral endplates.
`The present invention is directed at overcoming, or at least
`minimizing, the disadvantages of the prior art.
`
`SUMMARY OF THE INVENTION
`
`The present invention overcomes the drawbacks of the
`prior art by providing a spinal fusion implant of non-bone
`construction. The non-bone construction of the spinal fusion
`implant provides an advantage in that it is not supply limited
`and does not require harvesting bone from the patient (as with
`allograft). The present invention betterfacilitates cortical ring
`contact and fit between anterior ring portions of vertebral
`endplates, provides-Self distraction during insertion and rota
`tion, and avoids dural impingement.
`The spinal fusion implant of the present invention may be
`comprised of any Suitable non-bone composition, including
`but not limited to polymer compositions (e.g. poly-ether
`ether-ketone (PEEK) and/or poly-ether-ketone-ketone
`(PEKK)), ceramic, metal, or any combination of these mate
`rials. The spinal fusion implant of the present invention may
`be provided in any number of Suitable shapes and sizes
`depending upon the particular Surgical procedure or need.
`The spinal fusion implant may be dimensioned for use in any
`part of the spine (e.g. cervical, lumbar and/or thoracic) with
`out departing from the scope of the present invention. The
`implant may be dimensioned, by way of example only, having
`a width ranging between 8 and 14 mm, a height ranging
`between 8 and 18 mm, and a length ranging between 25 and
`45 mm.
`According to one broad aspect of the present invention, the
`spinal fusion implant includes a top surface, a bottom surface,
`lateral sides, a proximal end, and a distal end. The spinal
`fusion implant of the present invention may be used to pro
`vide temporary or permanent fixation along an orthopedic
`target site. To do so, the spinal fusion implant may be intro
`duced into a disc space while locked to a Surgical insertion
`instrument and thereafter manipulated in the proper orienta
`tion and released. Once deposited in the disc space, the spinal
`fusion implant of the present invention effects fusion over
`time as the natural healing process integrates and binds the
`implant.
`The spinal fusion implant of the present invention may be
`provided with any number of additional features for promot
`ing fusion, Such as one or more apertures extending between
`the top and bottom surfaces which allow a boney bridge to
`form through the spinal fusion implant. The spinal implant
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`may also be preferably equipped with one or more lateral
`openings which facilitate visualization at the time of implan
`tation and at Subsequent clinical evaluations.
`The spinal fusion implant may also be provided with any
`number of Suitable anti-migration features to prevent the
`implant from migrating or moving from the disc space after
`implantation. Suitable anti-migration features may include,
`but are not necessarily limited to, angled teeth or ridges
`formed along the top and bottom surfaces of the implant
`and/or rod elements disposed within the distal and/or proxi
`mal ends.
`According to a further aspect of the present invention, the
`spinal fusion implant may be provided with one or more
`radiographic markers at the proximal and/or distal ends.
`These markers allow for a more detailed visualization of the
`implant after insertion (through radiography) and allow for a
`more accurate and effective placement of the implant.
`According to a still further aspect of the present invention,
`the proximal end of the spinal fusion implant has a Surface
`that is tapered (angled) to avoid dural impingement after
`implantation. Additionally, the tapered nature of the proximal
`Surface can aid in overall fit of the spinal fusion implant
`within the intervertebral disc space. Significantly, the tapered
`proximal Surface on the proximal end enables the spinal
`fusion implant 10 to maximize contact with the posterior
`portion of the cortical ring of each adjacent vertebral body.
`According to a still further aspect of the present invention,
`the distal end of the spinal fusion implant has a conical (bul
`let-shaped) shape including a pair of first tapered (angled)
`Surfaces and a pair of second tapered (angled) surfaces. The
`first tapered surfaces extend between the lateral surfaces and
`the distal end of the implant, and function to distract the
`Vertebrae adjacent to the target intervertebral space during
`insertion of the spinal fusion implant. The second tapered
`surfaces extend between the top and bottom surfaces and the
`distal end of the spinal fusion implant, and function to maxi
`mize contact with the anterior portion of the cortical ring of
`each adjacent vertebral body. Furthermore, the second
`tapered surfaces provide for a better fit with the contour of the
`Vertebral body endplates, allowing for a more anterior posi
`tioning of the spinal fusion implant and thus advantageous
`utilization of the cortical rings of the vertebral bodies.
`According to a still further aspect of the present invention,
`the spinal fusion implant may be introduced into a spinal
`target site through use of any of a variety of Suitable Surgical
`instruments having the capability to engage the implant. The
`spinal fusion implant is capable of being used in minimally
`invasive Surgical procedures, needing only a relatively small
`operative corridor for insertion.
`According to a still further aspect of the present invention,
`once the implant has been positioned in its desired location
`within the intervertebral space, the user will then rotate the
`implant 90° such that the top and bottom surfaces face in a
`caudad/cephalad direction and the anti-migration features
`engage the vertebral bodies. Significantly, the direction of
`rotation is critical to ensure proper placement of the implant
`Such that the edges of the proximal Surface rest on the cortical
`ring of the vertebral bodies and the proximal surface does not
`protrude into the spinal canal. For example, if the spinal
`fusion implant approaches a patient's spine posteriorly from
`the right with the (longer) first lateral side facing caudally,
`then implant must be rotated in a counter-clockwise direction
`to achieve proper positioning.
`According to a still further aspect of the present invention,
`one or more of the spinal fusion implants of the present
`invention may be used in a variety of configurations in a
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`fusion procedure, including but not limited to (and by way of
`example only) unilateral, paired unilateral and bilateral.
`In a unilateral configuration, a single spinal fusion implant
`of the present invention is inserted into an intervertebral disc
`space and positioned obliquely across the disc space Such that
`the proximal and distal ends are on opposite sides of the
`midline of the intervertebral space.
`In a paired unilateral configuration, a first spinal fusion
`implant is inserted into the disc space and positioned
`obliquely within the intervertebral space, but not necessarily
`directly across the midline. A second spinal fusion implant is
`then inserted directly adjacent to the first implant such that the
`implants are in a side-by-side position.
`In a bilateral configuration, a first spinal fusion implant is
`inserted into the disc space, positioned obliquely, and dis
`posed entirely on one side of the midline of the intervertebral
`space. A second spinal fusion implant is the inserted into the
`disc space from the mirror-image postero-lateral approach
`Such that the second spinal fusion implant occupies the por
`tion of the intervertebral space on the opposite side of the
`midline from the first spinal fusion implant.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`Many advantages of the present invention will be apparent
`to those skilled in the art with a reading of this specification in
`conjunction with the attached drawings, wherein like refer
`ence numerals are applied to like elements and wherein:
`FIG. 1 is a perspective view of an example of a spinal
`fusion implant according to one embodiment of the present
`invention;
`FIG. 2 is a perspective view of an example of a spinal
`fusion implant according to an alternative embodiment of the
`present invention;
`FIG.3 is a top view of the spinal fusion implant of FIG. 2;
`FIG. 4 is a bottom view of the spinal fusion implant of FIG.
`2:
`FIG. 5 is a side view of the spinal fusion implant of FIG. 2;
`FIG. 6 is a plan view of a distal end of the spinal fusion
`implant of FIG. 2;
`FIG. 7 is a plan view of a proximal end view of the spinal
`fusion implant of FIG. 2;
`FIG. 8 is a top plan view of an example of a spinal fusion
`implant of the present invention inserted into an intervertebral
`space in a unilateral configuration;
`FIG. 9 is a top plan view of an example of a spinal fusion
`implant of the present invention inserted into an intervertebral
`space in a paired unilateral configuration; and
`FIG. 10 is a top plan view of an example of a spinal fusion
`implant of the present invention inserted into an intervertebral
`space in a bilateral configuration.
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENT
`
`Illustrative embodiments of the invention are described
`below. In the interest of clarity, not all features of an actual
`implementation are described in this specification. It will of
`course be appreciated that in the development of any Such
`actual embodiment, numerous implementation-specific deci
`sions must be made to achieve the developers specific goals,
`Such as compliance with system-related and business-related
`constraints, which will vary from one implementation to
`another. Moreover, it will be appreciated that such a develop
`ment effort might be complex and time-consuming, but
`would nevertheless be a routine undertaking for those of
`ordinary skill in the art having the benefit of this disclosure.
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`The spinal fusion implant disclosed herein boasts a variety of
`inventive features and components that warrant patent pro
`tection, both individually and in combination.
`FIG. 1 illustrates a spinal fusion implant 10 according to a
`first broad aspect of the present invention. The spinal fusion
`implant 10 may be constructed of any suitable non-bone
`composition, including but not limited to polymer composi
`tions (e.g. poly-ether-ether-ketone (PEEK) and/or poly-ether
`ketone-ketone (PEKK)), ceramic, metal and/or any combina
`tion of polymer compositions, ceramic and metal. The spinal
`fusion implant 10 of the present invention may be provided in
`any number of shapes and sizes depending upon the particular
`Surgical procedure or need. By way of example only, the
`spinal fusion implant 10 may have a width ranging between 8
`and 14 mm, a height ranging between 8 and 18 mm, and a
`length ranging between 25 and 45 mm.
`The spinal fusion implant 10 of the present invention
`includes a top Surface 12, a bottom Surface 14, first and
`second lateral sides 16, 17, a proximal (posterior) end 18 and
`a distal (anterior) end 20. The spinal fusion implant 10 of the
`present invention may be used to provide temporary or per
`manent fixation within an orthopedic target site. To do so, the
`spinal fusion implant 10 may be introduced into a disc space
`while locked to a Surgical insertion instrument and thereafter
`employed in the proper orientation and released, as explained
`in further detail below. Once deposited in the disc space, the
`spinal fusion implant 10 of the present invention effects spinal
`fusion over time as the natural healing process integrates and
`binds the implant.
`FIG. 2 illustrates a spinal fusion implant 10 according to an
`alternative embodiment of the present invention, having
`slightly different (and optional) features than the spinal
`fusion implant of FIG.1. Specifically, as will be discussed in
`greater detail below, the spinal fusion implant 10 of FIG. 2 is
`provided with an additional radiographic marker 27 at the
`proximal end and lateral recesses 42 for engagement with an
`insertion device.
`FIGS. 3-4 illustrate the top and bottom surfaces 12, 14,
`respectively, of the spinal fusion implant 10. As best depicted
`in FIG. 5, the top and bottom surfaces 12, 14 are not generally
`parallel to each other and may be angled or tapered from distal
`(anterior) end 20 to proximal (posterior) end 18. As such, the
`spinal fusion implant 10 of the present invention has a vari
`able height along the length of the implant, as measured by
`the distance between the top and bottom surfaces 12, 14. By
`45
`way of example only, this taper or incline may have a mea
`sured angle between 6 and 10 degrees. The practical result of
`this tapering is that the spinal fusion implant 10 has an ante
`rior height that is greater than the posterior height to provide
`a better fit within an intervertebral disc space. It can be appre
`ciated by one skilled in the art that the top and bottom surfaces
`12, 14 may be configured in any number of suitable shapes to
`better match the natural contours of the vertebral end plates.
`For example, although the top and bottom surfaces 12, 14 are
`shown in the FIGS. 1-7 as being generally planar, other con
`figurations (e.g. generally concave and/or convex) are pos
`sible.
`The top and bottom surfaces 12, 14 are configured to
`engage the vertebral bodies adjoining the target disc space.
`Accordingly, the top and bottom surfaces 12, 14 each prefer
`ably include a plurality of anti-migration features designed to
`increase the friction between the spinal fusion implant 10 and
`the adjacent contacting surfaces of the vertebral bodies. Such
`anti-migration features may include ridges (or teeth) 24 pro
`vided along the top surface 12 and/or bottom surface 14. The
`friction prohibits migration of the implant 10 after insertion
`into the intervertebral space and during the propagation of
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`natural bony fusion. It should be appreciated by one skilled in
`the art that such ridges (or teeth) 24 can be oriented in a
`particular direction which will stabilize the implant in several
`degrees of rotation during placement.
`The spinal fusion implant 10 of the present invention may
`also be provided with one or more radiographic markers to
`allow for visual determination of proper implant placement.
`As best appreciated in FIGS. 1, 2 and 5, the proximal end 18
`of implant 10 may be provided with at least a pair of radio
`graphic markers 26, each extending between one of the top
`and bottom surfaces 12, 14 and the proximal engagement
`recess 36. Preferably, radiographic markers 26 are positioned
`near the intersection of first lateral side 16 and proximal
`surface 34. Optionally, as shown in FIG. 2, the proximal
`implant 18 may be further provided with a pair of radio
`graphic markers 27, each extending between one of the top
`and bottom surfaces 12, 14 and the proximal engagement
`recess 36. Preferably, radiographic markers 27 are positioned
`near the intersection of second lateral side 17 and proximal
`surface 34. The distal end 20 may be provided with radio
`graphic marker 28 comprising a unitary element fully extend
`ing between the top and bottom surfaces 12, 14.
`The radiographic markers 26, 27, 28 may be provided in
`any size or shape Suitable to facilitate effective and accurate
`visualization of implant placement. For example, the spinal
`fusion implant 10 shown in FIGS. 1-7 include radiographic
`markers 26, 27, 28 in the form of elongated cylinders extend
`ing generally perpendicularly through the implant 10
`between the top and bottom surfaces 12, 14. Alternatively,
`radiographic markers 26, 27, 28 may include a shorter ele
`ment which extends only partially from either the top surface
`12 or the bottom surface 14 (that is, does not extend through
`the entire height of the implant 10). As a further alternative,
`radiographic markers 26, 27, 28 may extend at least partially
`(but not fully) toward either or both of top and bottom sur
`faces 12, 14 (that is, radiographic markers 26, 28 may be
`disposed completely within the body of the implant 10).
`The radiographic markers 26, 28 may be manufactured
`from any of a variety of suitable radiopaque materials, includ
`ing but not limited to a metal, ceramic, and/or polymer mate
`rial, preferably having radiopaque characteristics.
`The spinal fusion implant 10 includes a large aperture 30
`extending between top and bottom surfaces 12, 14. FIGS. 1-4
`illustrate aperture 30 extending in a vertical fashion between
`the top and bottom surfaces 12, 14. The aperture 30 may be
`provided in any number of Suitable shapes, including but not
`limited to generally circular, generally oblong, generally tri
`angular and/or generally rectangular (as shown by example in
`FIGS.3 and 4). This single aperture 30 is an additional feature
`for promoting fusion between the upper and lower vertebral
`bodies which allow a boney bridge to form through the spinal
`fusion implant 10.
`According to another further aspect of the present inven
`tion, this fusion may be facilitated or augmented by including
`osteoinductive material(s) within the aperture 30 and/or adja
`cent to the spinal fusion implant 10. Such osteoinductive
`materials may be introduced before, during, or after insertion
`of the spinal fusion implant 10 of the present invention, and
`may include (but are not necessarily limited to) autologous
`bone harvested from the patient receiving the spinal fusion
`implant 10, bone allograft, bone Xenograft, any number of
`non-bone implants (e.g. ceramic, metallic, polymer), bone
`morphogenic protein, and bio-resorbable compositions,
`including but not limited to any of a variety of poly (D.
`L-lactide-co-glycolide) based polymers, such as those dis
`closed in U.S. Pat. No. 6,013,853.
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`FIG. 5 depicts the spinal fusion implant 10 from a side
`view. First and second lateral sides 16, 17 are generally par
`allel to one another (shown best in FIGS. 3-4). Preferably, the
`first lateral side 16 has a greater length than the second lateral
`side 17. The effect of this disparity is to cause the proximal
`surface 34 to be angled or tapered from the first lateral surface
`16 to the second lateral surface 17. This angular surface
`provides an advantage by allowing an oblique positioning of
`the spinal fusion implant 10 within the intervertebral space,
`without protruding into the spinal canal, as will be explained
`in greater detail below. The spinal fusion implant 10 may be
`further provided with one or more lateral apertures 32 extend
`ing generally perpendicularly therethrough from one lateral
`side 16 to the other. Lateral apertures 32 function to provide
`visualization at the time of implantation and at Subsequent
`clinical evaluations. Lateral apertures 32 may be provided in
`any of a variety of suitable shapes, including but not limited to
`generally circular, generally oblong, generally triangular and/
`or generally rectangular (shown by example in FIG. 5), or any
`combination thereof. Although the spinal fusion implant 10
`examples shown in FIGS. 1-2 each include a pair of lateral
`apertures 32, the spinal implant fusion 10 may include any
`number of lateral apertures 10 as desired.
`More specifically, based on the generally radiolucent
`nature of the implant 10, the lateral apertures 32 provide the
`ability to visualize the interior of the implant 10 during X-ray
`and/or other suitable imaging techniques which are under
`taken from the lateral (or “side') perspective of the implant
`10. If fusion has taken place, the lateral apertures 32 will
`provide a method for the Surgeon to make follow up assess
`ments as to the degree of fusion without any visual interfer
`ence from the spinal fusion implant 10. Further, the lateral
`apertures 32 will provide an avenue for cellular migration to
`the exterior of the spinal fusion implant 10. Thus the spinal
`fusion implant 10 will serve as additional scaffolding for bone
`fusion on the exterior of the spinal fusion implant 10.
`FIG. 6 illustrates the proximal end 18 of the spinal fusion
`implant 10 of the present invention. The proximal end 18 has
`a proximal Surface 34 that is tapered (angled) to avoid dural
`impingement after insertion (as best illustrated in FIGS. 1-4).
`Additionally, the tapered nature of the proximal surface 34
`can aid in overall fit of the spinal fusion implant 10 within the
`Vertebral disc space. Significantly, the tapered proximal Sur
`face 34 on the proximal end 18 enables the spinal fusion
`implant 10 to maximize contact with the posterior portion of
`45
`the cortical ring of each adjacent vertebral body. The proxi
`mal end 18 may include a proximal engagement recess 36
`which extends inwardly in a generally perpendicular fashion
`relative to the proximal end 18. Although shown as having a
`generally rectangular cross-section, it will be appreciated that
`the proximal engagement recess 36 may be provided having
`any number of Suitable shapes or cross-sections, including
`but not limited to circular or triangular. Furthermore, the
`proximal engagement recess 36 may extend fully or at least
`partially along the length of the proximal surface 34. Proxi
`mal engagement recess 36 is dimensioned to receive and
`engage with an insertion tool (not shown) for inserting the
`spinal fusion implant 10 into the intervertebral space.
`FIG. 7 illustrates the distal end 20 of the spinal fusion
`implant 10 of the present invention. The distal end 20, as best
`illustrated in FIGS. 1 & 2, has a conical (bullet-shaped) shape
`including a pair of first tapered (angled) Surfaces 38 and a pair
`of second tapered (angled) Surfaces 40. First tapered Surfaces
`38 extend between lateral surfaces 16, 17 and the distal end
`20, and function to distract the vertebrae adjacent to the target
`intervertebral space during insertion of the spinal fusion
`implant 10. Second tapered surfaces 40 extend between top
`
`55
`
`8
`and bottom surfaces 12, 14 and the distal end 20, and function
`to maximize contact with the anterior portion of the cortical
`ring of each adjacent vertebral body. Furthermore, second
`tapered surfaces 40 provide for a better fit with the contour of
`the vertebral body endplates, allowing for a more anterior
`positioning of the spinal fusion implant 10 and thus advanta
`geous utilization of the cortical rings of the vertebral bodies.
`According to a broad aspect of the present invention, the
`spinal fusion implant 10 may be introduced into a spinal
`target site through use of any of a variety of suitable Surgical
`instruments having the capability to engage the implant 10.
`The spinal fusion implant 10 is capable of being used in
`minimally invasive Surgical procedures, needing only a rela
`tively small operative corridor for insertion. By way of
`example only, the spinal fusion implant 10 will now be
`described in relation to a transforaminal lumbar interbody
`fusion (TLIF) technique, in which the intervertebral disc
`space is approached from a postero-lateral direction, however
`it should be understood that the spinal fusion implant 10 is
`capable of use in a variety of Surgical procedures not
`described herein. After creating of this operative corridor and
`preparing the disc space (using techniques commonly known
`and used in the art), the spinal fusion implant 10 is mated to an
`insertion device (not shown) and advanced through the opera
`tive corridor toward the target intervertebral space. At this
`point the spinal fusion implant 10 is oriented with the lateral
`sides 16, 17 facing in a caudad/cephalad direction, for
`example with the first lateral side 16 facing a caudad (inferior)
`direction and the second lateral side 17 facing a cephalad
`(superior) direction. When the distal end 20 of the implant 10
`reaches the intervertebral disc space, each of the pair of first
`tapered surfaces 38 will come into contact with one of the
`adjacent vertebral bodies. As the implant 10 is advanced into
`the intervertebral disc space, the pair of first tapered surfac