U.S. patent application number 11/581163 was filed with the patent office on 2007-02-08 for systems and techniques for restoring and maintaining intervertebral anatomy.
This patent application is currently assigned to Warsaw Orthopedic, Inc. (Successor in interest to SDGI Holdings, Inc.). Invention is credited to James P. Duncan, Kevin T. Foley, Sean M. Haddock, Jeffrey D. Moore, T. Andrew Simonton.
Application Number | 20070032872 11/581163 |
Document ID | / |
Family ID | 34826509 |
Filed Date | 2007-02-08 |
United States Patent
Application |
20070032872 |
Kind Code |
A1 |
Simonton; T. Andrew ; et
al. |
February 8, 2007 |
Systems and techniques for restoring and maintaining intervertebral
anatomy
Abstract
Techniques and systems for distracting a spinal disc space and
supporting adjacent vertebrae are provided. Trial instruments are
insertable into the disc space to determine a desired disc space
height and to select a corresponding implant. Implants can be also
be self-distracting and the implant providing the desired disc
space height can be implanted in the spinal disc space.
Inventors: |
Simonton; T. Andrew;
(Memphis, TN) ; Foley; Kevin T.; (Germantown,
TN) ; Haddock; Sean M.; (Memphis, TN) ;
Duncan; James P.; (Olive Branch, MS) ; Moore; Jeffrey
D.; (Olive Branch, MS) |
Correspondence
Address: |
KRIEG DEVAULT LLP
ONE INDIANA SQUARE, SUITE 2800
INDIANAPOLIS
IN
46204-2709
US
|
Assignee: |
Warsaw Orthopedic, Inc. (Successor
in interest to SDGI Holdings, Inc.)
Warsaw
IN
|
Family ID: |
34826509 |
Appl. No.: |
11/581163 |
Filed: |
October 13, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10766167 |
Jan 28, 2004 |
7125425 |
|
|
11581163 |
Oct 13, 2006 |
|
|
|
10274856 |
Oct 21, 2002 |
7063725 |
|
|
10766167 |
Jan 28, 2004 |
|
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|
Current U.S.
Class: |
623/17.11 ;
606/90 |
Current CPC
Class: |
A61F 2/4611 20130101;
A61F 2250/0064 20130101; A61F 2310/00359 20130101; A61F 2310/00017
20130101; A61F 2002/30975 20130101; A61F 2310/00023 20130101; A61F
2230/0082 20130101; A61F 2002/30354 20130101; A61B 17/025 20130101;
A61F 2210/0014 20130101; A61F 2002/3082 20130101; A61F 2002/30904
20130101; A61F 2002/30383 20130101; A61F 2310/00329 20130101; A61F
2/442 20130101; A61F 2310/00029 20130101; A61F 2002/2835 20130101;
A61F 2002/30772 20130101; A61F 2/4455 20130101; A61F 2250/0098
20130101; A61F 2/30965 20130101; A61F 2002/2817 20130101; A61F
2002/30266 20130101; A61F 2220/0025 20130101; A61F 2002/4635
20130101; A61F 2/447 20130101; A61B 2017/0256 20130101; A61F 2/4603
20130101; A61F 2002/30616 20130101; A61F 2002/30593 20130101; A61F
2002/4628 20130101; A61F 2220/0033 20130101; A61F 2/28 20130101;
A61F 2002/4629 20130101; A61F 2002/30813 20130101; A61F 2002/308
20130101; A61F 2230/0004 20130101; A61F 2002/4627 20130101; A61F
2002/3008 20130101; A61F 2002/30331 20130101; A61F 2002/30112
20130101; A61F 2002/4681 20130101; A61F 2002/30092 20130101; A61F
2310/00179 20130101; A61F 2/4684 20130101; A61F 2310/00293
20130101 |
Class at
Publication: |
623/017.11 ;
606/090 |
International
Class: |
A61F 2/44 20060101
A61F002/44; A61F 2/46 20070101 A61F002/46; A61B 17/88 20070101
A61B017/88 |
Claims
1-35. (canceled)
36. An implant insertion assembly, comprising: an intervertebral
implant having upper and lower surface and opposite lateral
surfaces extending between said upper and lower surfaces, each of
said lateral surfaces having a notch formed therein opening at a
proximal end of said implant; and an insertion instrument including
a shaft with a distal coupling portion engageable in said notches
of each of said opposite lateral surfaces of said implant, said
coupling portion including a pair of distally extending and spaced
apart fingers each positionable in a respective one of said
notches, said fingers including a first position relative to one
another for receiving said implant therebetween and a second
position wherein said fingers in said notches grip said implant
therebetween, wherein in said second position each of said fingers
are received in said respective notch without protruding outwardly
from said lateral surface adjacent said respective notch.
37. The assembly of claim 36, wherein said lateral surfaces
comprise outwardly facing surfaces of opposite sidewalls of said
implant.
38. The assembly of claim 36, wherein said shaft of said insertion
instrument includes an outer shaft with said coupling portion at a
distal end of said outer shaft, and an inner shaft extending
through said outer shaft, said inner shaft including a distal end
extending between said fingers and a proximal end extending
proximally from said outer shaft.
39. The assembly of claim 38, further comprising a handle adjacent
said proximal end of said outer shaft, said inner shaft extending
proximally of said handle, and said handle being obliquely oriented
to said outer shaft.
40. The assembly of claim 38, wherein said inner shaft includes an
adjustment member at a proximal end thereof, said adjustment member
being operable to rotate said inner shaft in said outer shaft.
41. The assembly of claim 40, wherein said distal end of said inner
shaft is threaded for engagement with a threaded hole in a trailing
end wall of said implant.
42. The assembly of claim 40, wherein said outer shaft includes a
housing portion at said proximal end of said outer shaft, said
adjustment member being positioned in said housing portion.
43. The assembly of claim 36, wherein said coupling portion
includes a body member and said pair of fingers extends distally
from said body member on opposite sides thereof.
44. The assembly of claim 43, wherein said shaft of said insertion
instrument includes an outer shaft with said body member at a
distal end of said outer shaft, and an inner shaft extending
through said outer shaft and through a passage of said body member,
said inner shaft including a distal end extending between said
fingers.
45. The assembly of claim 43, wherein said shaft of said insertion
instrument includes an outer shaft and an inner shaft with said
body member at a distal end of said inner shaft, said inner shaft
extending through said outer shaft with said body member positioned
distally of a distal end of said outer shaft.
46. The assembly of claim 45, wherein said body member includes a
pair of biasing members spaced from one another with a slot
therebetween, said pair of fingers extending distally from
respective ones of said biasing members.
47. The assembly of claim 46, wherein said pair of biasing members
extend distally from a base portion of said body member, said base
portion including a proximally tapered outer surface profile,
wherein said outer shaft is distally advanceable along said outer
surface of said base portion to move said pair of biasing members
and said pair of fingers toward one another to grip said implant
therebetween.
48. The assembly of claim 46, wherein in said first position each
of said fingers are disengaged from said implant and received in
said respective notch without protruding outwardly from said
lateral surface adjacent said respective notch.
49. A spinal implant, comprising: an elongated body sized for
positioning in a spinal disc space and extending along a
longitudinal axis between a distal leading end portion and an
opposite trailing end portion, said body further comprising:
opposite first and second sidewalls extending along said
longitudinal axis between said leading end portion and said
trailing end portion, said first and second sidewalls extending
parallel to one another at least adjacent said leading end portion
of said body; an upper surface and an opposite lower surface
extending along said body between said first and second sidewalls
and between said leading end portion and said trailing end portion,
wherein said upper and lower surfaces are each convexly curved
along said longitudinal axis; a cavity extending between and
opening through said upper and lower surfaces; a number of engaging
members extending from said upper and lower surfaces around said
cavity for engaging an adjacent vertebral endplate; at least one
hole in each of said first and second sidewalls in communication
with said cavity; and wherein said leading end portion includes
convexly curved and smooth upper and lower surface portions
extending along said longitudinal axis from said engaging members
toward a leading end of said body.
50. The implant of claim 49, wherein said upper and lower surfaces
are smooth adjacent said trailing end portion of said implant.
51. The implant of claim 49, wherein said first and second
sidewalls are parallel to one another along an entire length of
said body.
52. The implant of claim 49, wherein said leading end is convexly
curved between said upper and lower surface portions.
53. The implant of claim 49, wherein said body includes: a first
notch in said first sidewall of said body; and a second notch in
said second sidewall of said body, said first and second notches
opening at a proximal end wall of said body.
54. The implant of claim 53, wherein said proximal end wall is
planar and extends between said first and second sidewalls and said
upper and lower surfaces.
55. The implant of claim 49, wherein said cavity includes an oval
shape elongated along said longitudinal axis and defined by inner
surfaces of said first and second sidewalls of said body, said
inner surfaces extending parallel to one another along said
cavity.
56. The implant of claim 55, wherein said inner surfaces of said
first and second sidewalls are connected at one end thereof with a
curved inner surface adjacent said leading end portion and at an
opposite end thereof with a curved inner surface adjacent said
trailing end portion.
57. The implant of claim 55, wherein said cavity extends along more
than half a length of said body between said leading end portion
and said trailing end portion.
58. A spinal implant, comprising: an elongated body sized for
positioning in a spinal disc space and extending along a
longitudinal axis between a leading end and an opposite trailing
end, said body further comprising: opposite first and second
sidewalls extending along said longitudinal axis between said
leading end and said trailing end; an upper surface and an opposite
lower surface extending along said body between said first and
second sidewalls and between said leading end and said trailing
end, wherein said upper and lower surfaces are each convexly curved
along said longitudinal axis, a cavity extending between and
opening through said upper and lower surfaces; and a number of
engaging members extending from said upper and lower surfaces
around said cavity, said engaging members being configured for
engaging an adjacent vertebral endplate, wherein said upper and
lower surfaces each include a convexly curved smooth surface
portion adjacent said leading end extending from said cavity toward
said leading end.
59. The implant of claim 58, wherein said first and second
sidewalls extending parallel to one another at least adjacent said
leading end of said body.
60. The implant of claim 58, further comprising at least one hole
in each of said first and second sidewalls in communication with
said cavity.
61. The implant of claim 58, wherein said upper and lower surfaces
are smooth adjacent said trailing end of said implant.
62. The implant of claim 58, wherein said leading end is convexly
curved between said upper surface and said lower surface.
63. The implant of claim 58, wherein said cavity includes an
elongated oval shape extending along more than half of a length of
said body along said longitudinal axis, said cavity being defined
by inner surfaces of said first and second sidewalls of said body,
said inner surfaces extending parallel to one another along said
cavity.
64. The implant of claim 58, wherein said smooth surface portions
further extend between said first and second sidewalls.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. patent
application Ser. No. 10/766,167 filed on Jan. 28, 2004, which is a
continuation-in-part of U.S. patent application Ser. No. 10/274,856
filed on Oct. 21, 2002, each of which is incorporated herein by
reference in its entirety.
BACKGROUND
[0002] Various surgical instruments and methods have been devised
for the implantation of devices into the disc space between
adjacent vertebrae of the spinal column. For example, spinal fusion
procedures can require sequential distraction to restore the disc
space height prior to inserting a pair of fusion devices in the
disc space in side-by-side relation. To implant these devices, an
initial opening or openings are made in the disc space at the
locations through which the devices are to be inserted. A first
distractor is inserted in the disc space at one of the device
locations. A second larger distractor is inserted in the disc space
at the other of the device locations. Sequential distraction in
alternate disc space locations is continued until the desired disc
space height is achieved. The next to last inserted distractor is
then removed. The disc space is prepared for insertion of one
fusion device in the location previously occupied by the withdrawn
distractor while the other distractor maintains the restored disc
space height.
[0003] In another technique, a spinal disc space is accessed and
distracted for insertion of an implant. Distraction of the disc
space is maintained by applying a distraction force to bone screws
engaged in the vertebrae on each side of the disc space.
[0004] While the above procedure can be effective for some
techniques, there are disadvantages. For example, dissection and
retraction of tissue, vasculature and nervature is required to
accommodate the pair of distractors inserted in the disc space, or
to accommodate the external distractors. Alternating sequential
distraction can be time-consuming and requires many steps to
complete the surgical procedure. Engagement of bone screws to the
vertebrae and application of a distraction force to the engaged
bone screws also requires additional time and steps in the surgical
procedure.
[0005] There remains a need for instruments and techniques for
restoring and maintaining a spinal disc space anatomy that
minimizes dissection and retraction and of tissue, vasculature and
nervature. There further remains a need for instruments and
techniques for restoring and maintaining a spinal disc space
anatomy that minimizes the steps and complexity of the procedure
during surgery.
SUMMARY
[0006] Implants are provided that can be sequentially inserted and
withdrawn from a spinal disc space to restore the disc space to a
desired disc space height and to post-operatively maintain the
desired spinal disc space height when a selected implant is left in
the spinal disc space.
[0007] Instruments are provided for determining the desired disc
space height and for selecting an implant providing the desired
disc space height when inserted in the collapsed disc space.
[0008] Implants are provided that can have the same height and
leading end portion configuration of at least some trial
instruments of a set of trial instruments. Each trial instrument of
the set has a trial body providing a restored disc space height and
a leading end portion configured to distract the disc space to the
restored disc space height.
[0009] Implants are provided that have a self-distracting lead end
configuration.
[0010] Instruments for inserting implants are also provided.
[0011] Related aspects, forms, and embodiments will be apparent
from the following description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIGS. 1A and 1B are elevation views of a self-distracting
trial instrument and a pair of adjacent vertebrae before and after
insertion of the trial instrument.
[0013] FIGS. 2A and 2B are elevation views of a self-distracting
implant and a pair of vertebrae before and after insertion of the
implant.
[0014] FIGS. 3A and 3B are elevation views of a distal portion of
another embodiment self-distracting trial instrument and a pair of
adjacent vertebrae before and after insertion of the trial
instrument.
[0015] FIGS. 4A and 4B are elevation views of another embodiment
self-distracting implant and a pair of adjacent vertebrae before
and after insertion of the implant.
[0016] FIG. 5 shows a set of trial instruments.
[0017] FIG. 6 shows a set of implants and implant insertion
instruments.
[0018] FIG. 7 is a perspective view of another embodiment implant
and implant insertion instrument.
[0019] FIG. 8 is a perspective view of an embodiment of the implant
of FIG. 7.
[0020] FIG. 9 is an exploded perspective view of the implant of
FIG. 8.
[0021] FIG. 10A is an elevation view of a proximal end of the
implant of FIG. 7 coupled to the insertion instrument.
[0022] FIG. 10B is an elevation view of the proximal end of the
implant of FIG. 7 uncoupled from the insertion instrument.
[0023] FIGS. 11A and 11B are a plan view and side view,
respectively, of a distal portion of another embodiment trial
instrument.
[0024] FIGS. 12A and 12B are a plan view and side view,
respectively, of a distal portion of another embodiment trial
instrument.
[0025] FIGS. 13A and 13B are a plan view and side view,
respectively, of a distal portion of another embodiment trial
instrument.
[0026] FIGS. 14A and 14B are a plan view and side view,
respectively, of a distal portion of another embodiment trial
instrument.
[0027] FIGS. 15A and 15B are a plan view and side view,
respectively, of a distal portion of another embodiment trial
instrument.
[0028] FIGS. 16A and 16B are a plan view and side view,
respectively, of a distal portion of another embodiment trial
instrument.
[0029] FIGS. 17A and 17B are a plan view and side view,
respectively, of a distal portion of another embodiment trial
instrument.
[0030] FIGS. 18A and 18B are a plan view and side view,
respectively, of a distal portion of another embodiment trial
instrument.
[0031] FIGS. 19A and 19B are a plan view and side view,
respectively, of a distal portion of another embodiment trial
instrument.
[0032] FIGS. 20A and 20B are a plan view and side view,
respectively, of a distal portion of another embodiment trial
instrument.
[0033] FIGS. 21A and 21B are a plan view and side view,
respectively, of a distal portion of another embodiment trial
instrument.
[0034] FIGS. 22A and 22B are a plan view and side view,
respectively, of a distal portion of another embodiment trial
instrument.
[0035] FIGS. 23A and 23B are a plan view and side view,
respectively, of a distal portion of another embodiment trial
instrument.
[0036] FIGS. 24A and 24B are a plan view and side view,
respectively, of a distal portion of another embodiment trial
instrument.
[0037] FIGS. 25A and 25B are a plan view and side view,
respectively, of a distal portion of another embodiment trial
instrument.
[0038] FIGS. 26A and 26B are a plan view and side view,
respectively, of a distal portion of another embodiment trial
instrument.
[0039] FIGS. 27A and 27B are a plan view and side view,
respectively, of a distal portion of another embodiment trial
instrument.
[0040] FIGS. 28A and 28B are a plan view and side view,
respectively, of a distal portion of another embodiment trial
instrument.
[0041] FIGS. 29A and 29B are a plan view and side view,
respectively, of a distal portion of another embodiment trial
instrument.
[0042] FIG. 30 is an elevation view of another embodiment
implant.
[0043] FIG. 31 is an end view of the implant of FIG. 30.
[0044] FIG. 32 is a section view through line 32-32 of FIG. 30.
[0045] FIG. 33 is an enlarged view of a portion of the implant of
FIG. 30.
[0046] FIG. 34 is a perspective view of another embodiment
implant.
[0047] FIG. 35 is a perspective view of another embodiment
implant.
[0048] FIG. 36 is a perspective view of another embodiment
insertion instrument.
[0049] FIG. 37 is an enlarged view of a distal end of the insertion
instrument of FIG. 36.
[0050] FIG. 38 is a view of the distal end of the insertion
instrument engaged to a trailing end of an implant.
[0051] FIG. 39 is a perspective view of another embodiment
insertion instrument.
DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
[0052] For the purposes of promoting an understanding of the
principles of the invention, reference will now be made to the
embodiments illustrated in the drawings and specific language will
be used to describe the same. It will nevertheless be understood
that no limitation of the scope of the invention is thereby
intended. Any such alterations and further modifications in the
illustrated device, and any such further applications of the
principles of the invention as illustrated therein being
contemplated as would normally occur to one skilled in the art to
which the invention relates.
[0053] Methods, techniques, instrumentation and implants are
provided to restore and/or maintain a collapsed spinal disc space
at a desired disc space height. The instruments and implants may be
used in techniques employing minimally invasive instruments and
technology to access the disc space. Access to the collapsed disc
space can be uni-portal, bi-portal, or multi-portal. The
instruments and implants may also be employed in open surgical
procedures in which skin and tissue is dissected and retracted to
access the collapsed spinal disc space. The methods, techniques,
instruments and implants may also be employed in any surgical
approach to the spine, including lateral, antero-lateral,
postero-lateral, posterior, and anterior approaches. Also, the
surgical methods, techniques, instruments and implants may find
application at all vertebral segments of the spine, including the
lumbar, thoracic and cervical spinal regions.
[0054] Referring now to FIG. 1A, there is shown an implant trial
instrument 20 having a proximal handle 22, a shaft 24 extending
distally from handle 22, and a trial body 26. Trial body 26
includes a proximal end 28 connected with or formed with a distal
end of shaft 24 and a leading insertion end 30. Trial body 26
further includes an upper surface 26a and an opposite lower surface
26b. Trial body has a height H1 between upper surface 26a and lower
surface 26b. Proximal end 28 can be tapered or otherwise configured
to provide a gradual transition between surfaces 26a, 26b to
facilitate withdrawal of trial body 26 from the spinal disc
space.
[0055] Trial instrument 20 is insertable into a collapsed disc
space D between adjacent vertebrae V1 and V2. Leading end portion
30 can be provided with a rounded nose-like shape that allows at
least a portion of leading end portion 30 to be inserted into a
collapsed, undistracted disc space D. As trial body 26 is advanced
into disc space D, the edges of vertebrae V1 and V2 ride upwardly
and downwardly, respectively, along the rounded nose portion of
leading end portion 30. Once leading end portion 30 is completely
inserted, collapsed disc space D is distracted to restore disc
space D', as shown in FIG. 1B. Restored disc space D' has a height
between the endplates of the adjacent vertebrae V1, V2 which
corresponds to height H1 of trial body 26 between upper surface 26a
and lower surface 26b.
[0056] With trial body 26 inserted in disc space D, the surgeon can
determine whether disc space D has been adequately distracted or
positioned to a desired disc space height by the tactile feel and
visual inspection of trial instrument 20 in the disc space. For
example, if trial instrument 20 is easily moved, or does not
provide a snug fit, then a trial instrument 20 may be withdrawn and
a second trial instrument having a trial body with a greater height
H1 is inserted. Alternatively, if the fit of trial body 26 is too
tight or won't fit, it can be withdrawn and another trial
instrument having a trial body with a smaller height HI can be
inserted in disc space D. The particular trial instrument 20
providing a restored disc space height that corresponds to a
desired disc space height is noted by the surgeon for selection of
an implant.
[0057] In FIG. 2A there is shown an implant 40 having a body 42.
Body 42 includes a proximal end 44 and a leading insertion end 46.
Body 42 further includes an upper surface 42a and an opposite lower
surface 42b. Body 42 has a height H1 between surfaces 42a, 42b.
Leading insertion end 46 is the same size and shape as leading end
portion 30 of trial body 26. Height H1 between surfaces 42a, 42b of
implant body 42 is also the same of height H1 between surfaces 26a,
26b of trial body 26.
[0058] In use, implant 40 can be selected from a set of implants
corresponding in size and shape with a set of trial instrument
bodies 26. The selected implant corresponds in size and shape with
the trial body 26 providing the desired fit and desired disc space
height for collapsed disc space D. Once implant 40 is selected,
trial body 26 is withdrawn from restored disc space D', and
restored disc space D' at least partially collapses. Implant 40 has
a leading end portion 46 that is the same size and shape as that of
trial body 26, and implant 40 will be insertable into the collapsed
disc space D since trial body 26 was insertable in collapsed disc
space D. Implant 40 restores and post-operatively maintains the
collapsed disc space D at a desired disc space height H1 between
vertebrae V1 and V2, as shown in FIG. 2B.
[0059] Referring to FIG. 3A, an alternate embodiment trial
instrument 20' is shown. Trial instrument 20' can include a
proximal handle (not shown), a shaft 24 extending distally from the
handle, and a trial body 26'. Trial body 26' includes a proximal
end 28' connected with or formed with a distal end of shaft 24' and
a leading insertion end 30'. Trial body 26' further includes an
upper surface 26a' and an opposite lower surface 26b'. Trial body
has a height H1 between upper surface 26a' and lower surface 26b'.
Proximal end 28' can be tapered or otherwise configured to provide
a gradual transition between surfaces 26a', 26b' to facilitate
withdrawal of trial body 26' from the spinal disc space.
[0060] Trial instrument 20' is insertable into a collapsed disc
space D between adjacent vertebrae V1 and V2. Leading end portion
30' can be provided with an aggressively tapered nose portion as
compared to leading end portion 30, which is overlaid on leading
end portion 30' in FIG. 3A for comparison. Leading end portion 30'
can have a pointed or blunt end nose portion 30a'. Nose portion
30a' can be relatively small in height for insertion into a
severely collapsed disc space D. For example, the height of nose
portion 30a' can be in the range from 3 millimeters or less to
about 5 or 6 millimeters. Leading end portion 30' further includes
an upper transition surface 30b' and a lower transition surface
30c'. Transition surfaces 30b', 30c' extend from nose portion 30a'
to respective ones of the upper surface 26a' and lower surface
26b'. Transition surfaces 30b', 30c' provide a smooth and gradual
transition for separation of collapsed vertebrae V1 and V2 as trial
body 26' is advanced into collapsed disc space D. As shown in FIG.
3B, once leading end portion 30' is completely inserted, collapsed
disc space D is distracted or restored by body 26'. Vertebrae V1'
and V2' can be separated by height H1 to provide restored disc
space D' having a height between the endplates of the adjacent
vertebrae which corresponds to height H1 of trial body 26' between
upper surface 26a' and lower surface 26b'.
[0061] In FIG. 4A there is shown an implant 40' having a body 42'.
Body 42' includes a proximal end 44' and a leading insertion end
46'. Body 42' further includes an upper surface 42a' and an
opposite lower surface 42b'. Body 42' has a height H1 between
surfaces 42a', 42b'. Leading insertion end 46' is the same size and
shape as leading end portion 30' of trial body 26'. Height H1
between surfaces 42a', 42b' of implant body 42' has height H1
between surfaces 26a', 26b' of trial body 26'.
[0062] Leading end portion 46' can be provided with an aggressively
tapered nose portion such as that provided with leading end portion
30' of trial instrument 20'. Leading end portion 46' can have a
pointed or blunt nose portion 46a'. Nose portion 46a' can be
relatively small in height for insertion into a severely collapsed
disc space D. For example, the height of nose portion 46a' can
range from 3 millimeters or less to about 5 to 6 millimeters.
Leading end portion 46' further includes an upper transition
surface 46b' and a lower transition surface 46c'. Transition
surfaces 46b', 46c' extend from nose portion 46a' to respective
ones of the upper surface 42a' and lower surface 42b'. Transition
surfaces 46b', 46c' provide a smooth and gradual transition for
separation of collapsed vertebrae V1 and V2 as implant body 42' is
advanced into collapsed disc space D. Leading end portion 46' is
completely inserted to restore collapsed disc space D. As shown in
FIG. 4B, the distracted or restored disc space D' between vertebrae
V1' and V2' has a height between the endplates of the adjacent
vertebrae V1', V2' which corresponds to the height H1 of implant
body 42' between upper surface 42a' and lower surface 42b'.
[0063] In use, implant 40' can be selected from a set of implants
having similar configurations but different heights H1. Implant 40'
can be selected to correspond in height with the trial body 26'
providing the desired fit and desired disc space height for
collapsed disc space D. Once implant 40' is selected, the last
inserted trial body 26' is withdrawn from restored disc space D',
and restored disc space D' collapses. However, since leading end
portion 46' of implant 40' is the same as that of leading end
portion 30' of trial body 26', and the last inserted trial body 26'
was insertable in the collapsed disc space D, the selected implant
40' will also be insertable in the collapsed disc space D. Implant
40' thus provides a restored disc space D' corresponding to the
desired disc space height indicated by trial body 26', and the
selected and inserted implant 40' post-operatively maintains the
restored disc space D' at a desired disc space height H1 .
[0064] In the embodiments of FIGS. 1A-4B, it is contemplated that
implants 40, 40' could be releasably attachable to the distal end
of shaft 24 for insertion into collapsed disc space D. It is
further contemplated that, rather than providing separate trial
instruments, a series of implants 40, 40' could be provided of
increasing height H1. The surgeon could insert and, if necessary,
withdraw various ones of the implants 40, 40' to determine which of
the various height implants provide a desired disc space height.
The implant providing the desired disc space height can be left in
the disc space to post-operatively maintain the desired disc space
height. The number of steps in the surgical procedure and time
required for surgery can be further reduced by providing such
self-distracting implants that do not require pre-distraction of
the collapsed disc space for insertion. However, providing trial
instruments can be advantageous for implants made from some types
of bone material or other material that may not withstand impaction
into a collapsed disc space since the trial instruments provide an
indication that the implant will fit before it is impacted into the
disc space, reducing the chance of damaging the implant during
withdrawal or during insertion.
[0065] It is further contemplated that implants 40' can be provided
in a set of implants having increasing heights H1. The height at
leading end portion 46' can be the same for each implant 40' of the
set so that any of the implants of the set could be selected for
insertion into the collapsed disc space when it is initially
accessed. Sequential distraction with the implants 40' may not be
needed or can be minimized if one of the first selected implants
provides the desired disc space height and fit. For example, each
of the various height implants 40' of the set can include
transition surfaces 46b', 46c' that taper from the same height nose
portion 46a' provided on each implant to the differing heights H1
between upper and lower surfaces 42a', 42b' provided on each
implant.
[0066] In FIG. 5 there is shown a trial instrument set 50 having a
number of trial instruments 52, 54, 56, 58, 60, 62, 64, 66, 68 and
70. Trial instrument 52 includes a handle 52a, a shaft 52b
extending distally from handle 52a, and a trial body 52c. Each of
the other trial instruments also includes a handle, a shaft and a
trial body. It is contemplated that each trial body of the trial
instruments provides a different height between an upper and a
lower contact surface thereof for restoring a collapsed disc space.
For example, trial instrument 52 can be provided with a trial body
having the smallest height H of the instrument set 50, and trial
instrument 70 can be provided with a trial body having the largest
height H' of the instrument set 50. The remaining trial instruments
can provide a number of different height trial instruments ranging
in height between H and H'. In one particular embodiment of
instrument set 50, the height of the trial instruments in the set
increase in one millimeter increments. In another particular
embodiment, the heights range from 6 millimeters to 15 millimeters
in one millimeter increments. Other increments and other ranges of
heights are also contemplated.
[0067] In FIG. 6 there is shown a set 80 of implant insertion
instruments 82, 84, 86. Implant insertion instrument 82 includes a
handle 82a, a shaft 82b, and an implant 82c releasably coupled to
the distal end of shaft 82b. Implant 82c can have a height H'''
between its upper and lower vertebral contacting surfaces. Implant
insertion instrument 84 includes a handle 84a, a shaft 84b, and an
implant 84c releasably coupled to the distal end of shaft 84b.
Implant 84c can have a height H'' between its upper and lower
vertebral contacting surfaces. Implant insertion instrument 86
includes a handle 86a, a shaft 86b, and an implant 86c releasably
coupled to the distal end of shaft 86b. Implant 86c can have a
height H' between its upper and lower vertebral contacting
surfaces. As further shown in FIG. 6, each of the implants 82c,
84c, 86c is releasable from its insertion instrument so that any
one of implants 82c, 84c, 86c can be selected for insertion and
post-operative implantation in the disc space.
[0068] It is contemplated that implant insertion instrument set 80
can be provided with trial instrument set 50. Each of the implants
can be preloaded on an instrument shaft to save time during
surgery. However, each of the implants could also be provided
separated with a single instrument shaft and then, when the desired
implant height is determined, the appropriate implant coupled to
the instrument shaft. Heights H''', H'', and H' of implants 82c,
84c, 86c correspond to the heights H''', H'', H' of the trial
bodies of trial instruments 66, 68, and 70, respectively.
Accordingly, the surgeon determines which of the trial bodies of
trial instruments 66, 68 or 70 has a height providing the desired
fit in the disc space by alternately inserting selected ones of the
trial bodies in the disc space. The trial body providing the
desired disc space height is removed and the implant insertion
instrument providing an implant with the same height is selected,
and the implant is inserted into the disc space to restore and
maintain the desired disc space height.
[0069] It is contemplated that more than three implant insertion
instruments 82, 84, 86 could be provided with implant insertion
instrument set 80. For example, a set of implant insertion
instruments could be provided with implants each having a height
corresponding to the height of one of the trial bodies of trial
instrument set 50. It is further contemplated that, rather than
providing any trial instrument set 50, an implant insertion
instrument set 80 can be provided with a number of implants
providing the desired range of heights. The implants of the implant
insertion instrument set are sequentially inserted and, if
necessary, withdrawn from the collapsed disc space. The implant
providing the desired fit and desired disc space height is left in
the disc space to post-operatively maintain the disc space
height.
[0070] In FIG. 7 there is shown an implant 110 coupled to the
distal end of an insertion instrument 90. Insertion instrument 90
includes a proximal shaft 92 and a proximal end cap 94. An
intermediate hub 96 is located at the distal end of proximal shaft
92. A slap hammer or other instrument for assisting in impacting
implant 110 into a disc space can be secured about proximal shaft
92 and impacted against end cap 94 and/or hub 96.
[0071] Extending distally from hub 96 is an actuator assembly
including a first member 98 and a second member 100. First member
98 includes a coupling portion 108 at its distal end, and second
member 100 includes a coupling portion 104 at its distal end. First
and second members 98, 100 are pivotally coupled at pin 106 so that
at least one of the coupling portions 104, 108 is movable relative
to the other coupling portion about pin 106. In the illustrated
embodiment, coupling portion 104 is movable about pin 106 in the
directions of arrow P1 by moving handle 102 in the directions of
arrows P2 to engage and release implant 110 between coupling
members 104, 108.
[0072] In one embodiment, implant 110 is comprised of two or more
pieces of material that can be temporarily or permanently joined
together, and can be held together by insertion instrument 90
during insertion into the disc space. Implant 110 includes a
self-distracting leading end portion 116 to facilitate insertion in
a collapsed disc space. In another embodiment, implant 110 is
comprised of a single piece of material. The material comprising
implant 110 can be solid, porous, multiply drilled, perforated,
open and/or spongy, for example.
[0073] Further details regarding one embodiment of implant 110 are
shown in FIG. 8. Implant 110 includes a body 112 with an upper
surface 114 and an opposite lower surface 117. The upper and lower
surfaces 114, 117 can be provided with grooves, recesses, ridges,
serrations, knurlings, spikes, roughened surfaces, or smooth
surfaces for engaging the endplates of the adjacent vertebrae. Body
112 includes a leading end portion 116 that is rounded or tapered
configured so that body 112 distracts the adjacent vertebrae as it
is inserted in a collapsed disc space. Body 112 also includes a
proximal end wall 111, and sidewalls 113, 115 extending between
proximal end wall 111 and leading end portion 116. As shown in
FIGS. 10A and 10B, a first notch 124a in lateral wall 113 and a
second notch 124b in lateral wall 115 each extend distally from and
open at proximal end wall 111. First notch 124a can be provided
with an indent 126a therein, and second notch 124 can be provided
with an indent 126b therein.
[0074] In FIG. 9, implant 112 is shown in an exploded view. Body
112 can be provided in a first lateral section 112a and a second
lateral section 112b. Lateral sections 112a, 112b each include a
corresponding portion of the upper surface 114a, 114b, the lower
surface, and leading end portion 116a, 116b. One of the lateral
sections, such as lateral section 112a, can be provided with a bore
120, and the other of the lateral sections, such as lateral section
112b can be provided with a pin 118. Pin 118 is insertable into
bore 120 to secure lateral sections 112a, 112b to one another.
Lateral section 112a includes a medial surface 122a and lateral
section 112b includes a medial surface 122b. Medial surfaces 122a,
122b are positioned adjacent one another when lateral sections
112a, 122b are assembled. Medial surfaces 122a, 122b can each be
provided with peaks and valleys that interdigitate with peaks and
valleys of the other medial surface to assist in holding lateral
sections 112a, 112b together and prevent relative movement there
between. In the illustrated embodiment, the peaks and valleys
extend in the direction between upper surface 114 and lower surface
117. Other orientations for the peaks and valleys are also
contemplated, such as extending between leading end portion 116 and
proximal end 111, or extending diagonally.
[0075] In the embodiment of implant 110 discussed above, it is
contemplated that implant 110 can be made of cortical bone cut so
that the longitudinal axes of lateral sections 112a, 112b between
leading end portions 116a, 116b and proximal end 111 are parallel
to the longitudinal axis of the host bone from which the sections
are cut. By cutting through the host bone longitudinally to obtain
the implant sections, leading end portion 116 of implant 110 is
provided with maximum strength and durability to withstand
impaction of implant 110 into the disc space. Other embodiments of
implant 110 contemplate that implant 110 is provided as an integral
unit, and can be made from a single piece of bone material, or made
from non-bone material.
[0076] As shown in FIGS. 10A and 10B, the coupling portions 104,
108 are positionable in notches 124a, 124b to engage implant 110 to
insertion instrument 90. Coupling portion 104 can include a
protrusion 105 positionable in detent 126b, and coupling portion
108 can include a protrusion 109 positionable in detent 126a. In
FIG. 10A, coupling portions 104, 108 define a width W2 between the
lateral outside edges thereof that is less than a width W1 between
lateral walls 113, 115 of implant 110. Thus, coupling portions 104,
108 and insertion instrument 90 do not protrude laterally from
implant 110 during insertion. As shown in FIG. 10B, coupling
portions 104, 108 are moved away from one another to disengage
implant 110 and to remove protrusions 105, 109 from detents 126b,
126a, respectively so that insertion instrument 90 can be
longitudinally withdrawn from implant 110. The width between the
lateral outside edges of coupling members 104, 108 can be limited
in the uncoupled position to be the same as or less than width W1
of implant 110. In this manner, insertion instrument 90 can be
uncoupled from implant 110 while maintaining a low profile that
does not protrude or project laterally beyond lateral walls 113,
115. As a result, the pathway through which implant 110 is
positioned to the collapsed disc space need only be large enough to
accommodate implant 110.
[0077] Referring now to FIGS. 11A-11B, there is shown an embodiment
of a distal portion 140 of a trial instrument attachable to an
insertion instrument. Other embodiment distal portions 140 for
trial instruments are shown FIGS. 12A-20B that are similar to the
distal portion of FIG. 11A but with differing geometrical
properties for determining a desired disc space height. However, as
discussed further below, the distal portions of FIGS. 12A-20B have
geometrical properties which differ from distal portion 140,
providing a set of distal portions 140 which can be sequentially
inserted and withdrawn from a collapsed spinal disc space to
determine an appropriate implant for insertion therein. In
addition, it is contemplated that implants could be provided having
the same size and shape of each of the trial bodies of distal
portions 140 shown in FIGS. 11A-20B.
[0078] Distal portion 140 includes a trial body 142 and a shaft
coupling portion 144 extending proximally from trial body 142.
Shaft coupling portion 144 can be coupled to an insertion
instrument. Other embodiments contemplate that trial body 142 can
be integral with the insertion instrument. Contemplated coupling
arrangements between trial body 142 and the insertion instrument
include clamping connections, frictional connections, set screw
connections, threaded connections, bayonet connections, and
ball-detent connections, for example. Trial body 142 includes an
upper surface 142a and a lower surface 142b for contacting the
endplate of the adjacent vertebra. Trial body 142 also includes
lateral surfaces 142c and 142d. Rounded or tapered lateral
transition surfaces extend between upper and lower surfaces 142a,
142b and the respective lateral surfaces 142c, 142d. Trial body 142
further includes a leading end portion 146 and a proximal end 148.
Proximal end 148 can be tapered to facilitate withdrawal of trial
body 142 from the disc space. Leading end portion 146 includes a
nose portion 146a and rounded portions transitioning to the upper
and lower surfaces 142a, 142b.
[0079] Distal portion 140 includes an overall length L1, and trial
body 142 includes a length L2. Upper and lower surfaces 142a, 142b
can be curved along a radius R2 to generally mate with the
vertebral endplate geometry. The upper and lower transition
surfaces of leading end portion 146 can be curved along radius R2'.
Trial body 142 includes an overall maximum height H2 between upper
and lower surfaces 142a, 142b. Upper and lower surfaces 142a, 142b
can be curved to provide a height H2' at leading end 146. Height
H2' is less than height H2 to facilitate insertion of leading end
portion 146 into the spinal disc space. Trial body 142 can be
provided with an overall width W3 between lateral surfaces 142c and
142d.
[0080] In FIGS. 12A and 12B, distal portion 140 is provided with a
body 142 having upper and lower surfaces 142a, 142b curved along
radius R3. The upper and lower transition surfaces of leading end
portion 146 are curved along radius R3'. Trial body 142 has an
overall maximum height H3 between upper and lower surfaces 142a,
142b. Upper and lower surfaces 142a, 142b are curved to provide a
height H3' at leading end portion 146. Height H3' is less than
height H3 to facilitate insertion of leading end portion 146 into
the spinal disc space.
[0081] In FIGS. 13A and 13B, distal portion 140 is provided with a
body 142 having upper and lower surfaces 142a, 142b curved along
radius R4. The upper and lower transition surfaces of leading end
portion 146 are curved along radius R4'. Trial body 142 has an
overall maximum height H4 between upper and lower surfaces 142a,
142b. Upper and lower surfaces 142a, 142b are curved to provide a
height H4' at leading end portion 146. Height H4' is less than
height H4 to facilitate insertion of leading end portion 146 into
the spinal disc space.
[0082] In FIGS. 14A and 14B, distal portion 140 is provided with a
body 142 having upper and lower surfaces 142a, 142b curved along
radius R5. The upper and lower transition surfaces of leading end
portion 146 are curved along radius R5'. Trial body 142 has an
overall maximum height H5 between upper and lower surfaces 142a,
142b. Upper and lower surfaces 142a, 142b are curved to provide a
height H5' at leading end portion 146. Height H5' is less than
height H5 to facilitate insertion of leading end portion 146 into
the spinal disc space.
[0083] In FIGS. 15A and 15B, distal portion 140 is provided with a
body 142 having upper and lower surfaces 142a, 142b curved along
radius R6. The upper and lower transition surfaces of leading end
portion 146 are curved along radius R6'. Trial body 142 has an
overall maximum height H6 between upper and lower surfaces 142a,
142b. Upper and lower surfaces 142a, 142b are curved to provide a
height H6' at leading end portion 146. Height H6' is less than
height H6 to facilitate insertion of leading end portion 146 into
the spinal disc space.
[0084] In FIGS. 16A and 16B, distal portion 140 is provided with a
body 142 having upper and lower surfaces 142a, 142b curved along
radius R7. The upper and lower transition surfaces of leading end
portion 146 are curved along radius R7'. Trial body 142 has an
overall maximum height H7 between upper and lower surfaces 142a,
142b. Upper and lower surfaces 142a, 142b are curved to provide a
height H7' at leading end portion 146. Height H7' is less than
height H7 to facilitate insertion of leading end portion 146 into
the spinal disc space.
[0085] In FIGS. 17A and 17B, distal portion 140 is provided with a
body 142 having upper and lower surfaces 142a, 142b curved along
radius R8. The upper and lower transition surfaces of leading end
portion 146 are curved along radius R8'. Trial body 142 has an
overall maximum height H8 between upper and lower surfaces 142a,
142b. Upper and lower surfaces 142a, 142b are curved to provide a
height H8' at leading end portion 146. Height H8' is less than
height H8 to facilitate insertion of leading end portion 146 into
the spinal disc space. Upper and lower surfaces 142a, 142b further
taper along proximal end 148 to form angle .alpha. with the central
axis of the insertion instrument. Angle .alpha. provides a smooth
transition between coupling portion 144 and body 142 to prevent
body 142 from hanging up or catching on the vertebral endplates as
it is withdrawn.
[0086] In FIGS. 18A and 18B, distal portion 140 is provided with a
body 142 having upper and lower surfaces 142a, 142b curved along
radius R9. The upper and lower transition surfaces of leading end
portion 146 are curved along radius R9'. Trial body 142 has an
overall maximum height H9 between upper and lower surfaces 142a,
142b. Upper and lower surfaces 142a, 142b are curved to provide a
height H9' at leading end portion 146. Height H9' is less than
height H9 to facilitate insertion of leading end portion 146 into
the spinal disc space. Upper and lower surfaces 142a, 142b further
taper along proximal end 148 to form angle .alpha. with the central
axis of the insertion instrument.
[0087] In FIGS. 19A and 19B, distal portion 140 is provided with a
body 142 having upper and lower surfaces 142a, 142b curved along
radius R10. The upper and lower transition surfaces of leading end
portion 146 are curved along radius R10'. Trial body 142 has an
overall maximum height H10 between upper and lower surfaces 142a,
142b. Upper and lower surfaces 142a, 142b are curved to provide a
height H10' at leading end portion 146. Height H10' is less than
height H10 to facilitate insertion of leading end portion 146 into
the spinal disc space. Upper and lower surfaces 142a, 142b further
taper along proximal end 148 to form angle .alpha. with the central
axis of the insertion instrument.
[0088] In FIGS. 20A and 20B, distal portion 140 is provided with a
body 142 having upper and lower surfaces 142a, 142b curved along
radius R11. The upper and lower transition surfaces of leading end
portion 146 are curved along radius R11'. Trial body 142 has an
overall maximum height H11 between upper and lower surfaces 142a,
142b. Upper and lower surfaces 142a, 142b are curved to provide a
height H11' at leading end portion 146. Height H11' is less than
height H11 to facilitate insertion of leading end portion 146 into
the spinal disc space. Upper and lower surfaces 142a, 142b further
taper along proximal end 148 to form angle .alpha. with the central
axis of the insertion instrument.
[0089] It is contemplated that a set of self-distracting implants
could be provided by modifying each of the distal portions 140 of
FIGS. 11A-20B so that between its distal and proximal ends the
implant has a length that fits within a spinal disc space. For
example, shaft coupling portion 144 could be removed, or trial body
142 could be truncated at a proximal end wall 150. The proximal end
of the implant could includes a threaded hole in the proximal end
wall, notches in the lateral walls, or other suitable configuration
for releasable engagement with an insertion instrument.
[0090] In one specific embodiment of a trial instrument set
employing the distal portions of FIGS. 11A-20B, each of the bodies
142 can be provided with a width W3 of about 10 millimeters and a
length L1 of about 42 millimeters. Each of the distal portions 140
can be provided with an overall length L2 of about 60 millimeters.
Leading end portion 146 can be provided with a radius R of 5
millimeters between lateral surfaces 142c, 142d, and angle .alpha.
can be about 25 degrees.
[0091] In the specific embodiment, height H2 of the FIG. 11A
embodiment is 6 millimeters. Each of the heights H3 through H11 can
increase in one millimeter increments from height H2 to height H11.
Thus, height H11 is 15 millimeters. Furthermore, the reduced height
at each of the leading end portions, such as height H2' can be 4
millimeters, or 2 millimeters less than height H2. Similarly, each
of the heights H3' through H11' can be 2 millimeters less than the
corresponding heights H3 through H11. The radii R2' through R5'
transitioning between the nose portion 146a and upper and lower
surfaces 142a, 142b can each be 2 millimeters. Radii R6' and R7'
can each be 3 millimeters, and radii R8' through R11' can each be 4
millimeters.
[0092] The specific embodiment further contemplates that upper and
lower surface 142a, 142b have a different curvature for each of the
bodies 142 to conform to an adjacent vertebral endplate associated
with the particular distraction height provided by the particular
body 142. For example, radius R2 can about 221 millimeters, radius
R3 can be about 179 millimeters, radius R4 can be about 152
millimeters, radius R5 can be about 133 millimeters, radius R6 can
be about 119 millimeters, radius R7 can be about 108 millimeters,
radius R8 can be about 100 millimeters, radius R9 can be about 92
millimeters, radius R10 can be about 86 millimeters, and radius R11
can be about 81 millimeters.
[0093] While specific dimensional and geometrical features have
been provided for one particular embodiment of a set of distal
portions 140, it should be understood however, that such
dimensional and geometrical attributes are provided for a specific
embodiment, and other embodiments contemplate other dimensions than
those provided herein.
[0094] Referring now to FIGS. 21A-21B, there is shown an embodiment
of a distal portion 240 of a trial instrument attachable to an
insertion instrument. Other embodiment distal portions 240 for
trial instruments are shown FIGS. 22A-29B that are similar to the
distal portion of FIG. 21A but with differing geometric properties
for determining a desired disc space height. However, as discussed
further below, the distal portions of FIGS. 22A-29B have
geometrical properties which differ from the distal portion 240,
providing a set of distal portions 240 which can be sequentially
inserted and withdrawn from a collapsed spinal disc space to
determine an appropriate implant for insertion therein. In
addition, it is contemplated that implants could be provided having
the same size and shape of each of the trial bodies of the distal
portions 240 shown in FIGS. 21A-29B.
[0095] Distal portion 240 includes a trial body 242 and a shaft
coupling portion 244 extending proximally therefrom. Shaft coupling
portion 244 can be coupled to an insertion instrument. Other
embodiments contemplate that trial body 242 can be integral with
the insertion instrument. Contemplated coupling arrangements
between trial body 242 and the insertion instrument include
clamping connections, frictional connections, set screw
connections, threaded connections, bayonet connections, and
ball-detent connections, for example. Trial body 242 includes an
upper surface 242a and a lower surface 242b for contacting the
endplate of the adjacent vertebra. Trial body 242 also includes
lateral surfaces 242c and 242d. Rounded or tapered lateral
transition surfaces extend between upper and lower surfaces 242a,
242b and the respective lateral surfaces 242c, 242d. Trial body 242
further includes a leading end portion 246 and a proximal end 248.
Proximal end 248 can tapered to facilitate withdrawal of trial body
242 from the disc space. Leading end portion 246 includes a flat or
slightly rounded nose portion 246a and upper and lower transition
surfaces 246b, 246c extending therefrom. Upper and lower transition
surfaces 246b, 246c provide a gradually increasing distraction
height extending from nose portion 246a facilitate distraction of
the adjacent vertebrae.
[0096] Distal portion 240 includes an overall length L1, and trial
body 242 includes a length L2. Upper and lower surfaces 242a, 242b
can be curved along a radius R3 to generally mate with the
vertebral endplate geometry. The upper and lower transition
surfaces 246b, 246c of leading end portion 246 can be tapered along
angle A1 relative to a central axis extending longitudinally
through body 242. Trial body 242 includes an overall maximum height
H3 between upper and lower surfaces 242a, 242b. Upper and lower
surfaces 242a, 242b are tapered from height H3 to height H12 at
nose portion 246a. A radius R12 can provide a smooth transition
between transition surfaces 246b, 246c and nose portion 246a.
Height H12 is less than height H3 to facilitate insertion of
leading end portion 246 into the spinal disc space. Trial body 242
can be provided with an overall width W3 between lateral surfaces
242c and 242d.
[0097] In FIGS. 22A and 22B, distal portion 240 is provided with a
body 242 having upper and lower surfaces 242a, 242b curved along
radius R4. The upper and lower transition surfaces 246b, 246c of
leading end portion 246 can be tapered along angle A1 relative to
central axis C extending longitudinally through body 242. Trial
body 242 includes an overall maximum height H4 between upper and
lower surfaces 242a, 242b. Upper and lower surfaces 242a, 242b are
tapered from height H4 to height H12 at nose portion 246a. Radius
R12 can provide a smooth transition between transition surfaces
246b, 246c and nose portion 246a. Height H12 is less than height H4
to facilitate insertion of leading end portion 246 into the spinal
disc space.
[0098] In FIGS. 23A and 23B, distal portion 240 is provided with a
body 242 having upper and lower surfaces 242a, 242b curved along
radius R5. The upper and lower transition surfaces 246b, 246c of
leading end portion 246 can be tapered along angle A2 relative to
central axis C extending longitudinally through body 242. Trial
body 242 includes an overall maximum height H5 between upper and
lower surfaces 242a, 242b. Upper and lower surfaces 242a, 242b are
tapered from height H5 to height H12 at nose portion 246a. Radius
R12 can provide a smooth transition between transition surfaces
246b, 246c and nose portion 246a. Height H12 is less than height H5
to facilitate insertion of leading end portion 246 into the spinal
disc space.
[0099] In FIGS. 24A and 24B, distal portion 240 is provided with a
body 242 having upper and lower surfaces 242a, 242b curved along
radius R6. The upper and lower transition surfaces 246b, 246c of
leading end portion 246 can be tapered along angle A2 relative to
central axis C extending longitudinally through body 242. Trial
body 242 includes an overall maximum height H6 between upper and
lower surfaces 242a, 242b. Upper and lower surfaces 242a, 242b are
tapered from height H6 to height H12 at nose portion 246a. Radius
R12 can provide a smooth transition between transition surfaces
246b, 246c and nose portion 246a. Height H12 is less than height H6
to facilitate insertion of leading end portion 246 into the spinal
disc space.
[0100] In FIGS. 25A and 25B, distal portion 240 is provided with a
body 242 having upper and lower surfaces 242a, 242b curved along
radius R7. The upper and lower transition surfaces 246b, 246c of
leading end portion 246 can be tapered along angle A3 relative to
central axis C extending longitudinally through body 242. Trial
body 242 includes an overall maximum height H7 between upper and
lower surfaces 242a, 242b. Upper and lower surfaces 242a, 242b are
tapered from height H7 to height H12 at nose portion 246a. Radius
R12 can provide a smooth transition between transition surfaces
246b, 246c and nose portion 246a. Height H12 is less than height H7
to facilitate insertion of leading end portion 246 into the spinal
disc space.
[0101] In FIGS. 26A and 26B, distal portion 240 is provided with a
body 242 having upper and lower surfaces 242a, 242b curved along
radius R8. The upper and lower transition surfaces 246b, 246c of
leading end portion 246 can be tapered along angle A4 relative to
central axis C extending longitudinally through body 242. Trial
body 242 includes an overall maximum height H8 between upper and
lower surfaces 242a, 242b. Upper and lower surfaces 242a, 242b are
tapered from height H8 to height H12 at nose portion 246a. Radius
R12 can provide a smooth transition between transition surfaces
246b, 246c and nose portion 246a. Height H12 is less than height H8
to facilitate insertion of leading end portion 246 into the spinal
disc space. Upper and lower surfaces 242a, 242b further taper along
proximal end 248 to form angle .alpha. with the central axis of the
insertion instrument to provide a smooth transition between
coupling portion 244 and body 242 to prevent body 242 from hanging
up or catching on the vertebral endplates as it is withdrawn.
[0102] In FIGS. 27A and 27B, distal portion 240 is provided with a
body 242 having upper and lower surfaces 242a, 242b curved along
radius R9. The upper and lower transition surfaces 246b, 246c of
leading end portion 246 can be tapered along angle A4 relative to
central axis C extending longitudinally through body 242. Trial
body 242 includes an overall maximum height H9 between upper and
lower surfaces 242a, 242b. Upper and lower surfaces 242a, 242b are
tapered from height H9 to height H12 at nose portion 246a. Radius
R12 can provide a smooth transition between transition surfaces
246b, 246c and nose portion 246a. Height H12 is less than height H9
to facilitate insertion of leading end portion 246 into the spinal
disc space. Upper and lower surfaces 242a, 242b further taper along
proximal end 248 to form angle .alpha. with the central axis of the
insertion instrument to provide a smooth transition between
coupling portion 244 and body 242 to prevent body 242 from hanging
up or catching on the vertebral endplates as it is withdrawn.
[0103] In FIGS. 28A and 28B, distal portion 240 is provided with a
body 242 having upper and lower surfaces 242a, 242b curved along
radius R10. The upper and lower transition surfaces 246b, 246c of
leading end portion 246 can be tapered along angle A4 relative to
central axis C extending longitudinally through body 242. Trial
body 242 includes an overall maximum height H10 between upper and
lower surfaces 242a, 242b. Upper and lower surfaces 242a, 242b are
tapered from height H10 to height H12 at nose portion 246a. Radius
R12 can provide a smooth transition between transition surfaces
246b, 246c and nose portion 246a. Height H12 is less than height
H10 to facilitate insertion of leading end portion 246 into the
spinal disc space. Upper and lower surfaces 242a, 242b further
taper along proximal end 248 to form angle .alpha. with the central
axis of the insertion instrument.
[0104] In FIGS. 29A and 29B, distal portion 240 is provided with a
body 242 having upper and lower surfaces 242a, 242b curved along
radius R11. The upper and lower transition surfaces 246b, 246c of
leading end portion 246 can be tapered along angle A5 relative to
central axis C extending longitudinally through body 242. Trial
body 242 includes an overall maximum height H11 between upper and
lower surfaces 242a, 242b. Upper and lower surfaces 242a, 242b are
tapered from height H11 to height H12 at nose portion 246a. Radius
R12 can provide a smooth transition between transition surfaces
246b, 246c and nose portion 246a. Height H12 is less than height
H11 to facilitate insertion of leading end portion 246 into the
spinal disc space. Upper and lower surfaces 242a, 242b further
taper along proximal end 248 to form angle .alpha. with the central
axis of the insertion instrument.
[0105] It is contemplated that a set of self-distracting implants
could be provided by modifying each of the distal portions 240 of
FIGS. 21A-29B so that between its distal and proximal ends the
implant has a length that fits within a spinal disc space. For
example, shaft coupling portion 244 could be removed, or trial body
242 could be truncated at a proximal end wall 250. The proximal end
of the implant could includes a threaded hole in the proximal end
wall, notches in the lateral walls, or configuration for releasable
engagement with an insertion instrument.
[0106] In one specific embodiment of a trial instrument set
employing the distal portions of FIGS. 21A-29B, each of the bodies
242 can be provided with a width W3 of about 10 millimeters and a
length L1 of about 42 millimeters. Each of the distal portions 240
can be provided with an overall length L2 of about 60 millimeters.
Leading end portion 246 can be provided with a radius R of 5
millimeters between lateral surfaces 242c, 242d.
[0107] In the specific embodiment, height H3 of the FIG. 21A
embodiment is 7 millimeters. Each of the heights H4 through H11
increase in one millimeter increments from height H3 to height H11.
Thus, height H11 is 15 millimeters. Height H12 at nose portion 246a
is 3 millimeters for each of the bodies 242. The radii R12
transitioning between nose portion 246a and upper and lower
transition surfaces 246b, 246c can be about 1.5 millimeters.
[0108] Transition surfaces 246b, 246c extend between radius R12 and
the adjacent upper and lower surface 242a, 242b. The angular
orientation of transition surfaces 246b, 246c relative to the
central axis of the body 242 can range from angle A1 to angle A5
for various ones of the embodiments shown. In one specific
embodiment trial instrument set, angle A1 is about 15 degrees,
angle A2 is about 20 degrees, angle A3 is about 25 degrees, angle
A4 is about 30 degrees, and angle A5 is about 35 degrees. The
specific embodiment further contemplates that upper and lower
surface 242a, 242b can be provided with a different curvature for
each of the bodies 242. For example, radius R3 can be about 179
millimeters, radius R4 can be about 152 millimeters, radius R5 can
be about 133 millimeters, radius R6 can be about 119 millimeters,
radius R7 can be about 108 millimeters, radius R8 can be about 100
millimeters, radius R9 can be about 92 millimeters, radius R10 can
be about 86 millimeters, and radius R11 can be about 81
millimeters.
[0109] While specific dimensional and geometrical features have
been provided for one particular embodiment of a set of distal
portions 240, it should be understood however, that such
dimensional and geometrical attributes are provided for a specific
embodiment, and other embodiments contemplate other dimensions than
those provided herein.
[0110] Referring now to FIGS. 30-33, there is shown another
embodiment implant 310. Implant 310 includes a self-distracting
leading end portion 316 to facilitate insertion in a collapsed disc
space. Implant 310 can be comprised of a single piece of material
or multiple pieces of material as discussed above. Other examples
of assembled implants are provided in U.S. patent application Ser.
No. 10/669,779, which is incorporated herein by reference in its
entirety. The material comprising implant 310 can be solid, porous,
multiply drilled, perforated, open and/or spongy, for example.
Implant 310 can be fabricated from one or more pieces of bone
material, non-bone material, or combinations thereof.
[0111] Implant 310 includes a body 312 extending along a
longitudinal axis 319 between a leading end portion 316 and a
trailing end portion 311. Sidewalls 313, 315 extend along axis 319
between leading end portion 316 and trailing end portion 311. Body
312 includes an upper surface 314 and an opposite lower surface
317. The upper and lower surfaces 314, 317 can be provided with
engagement members 334, which can be comprised of any one or
combination of grooves, recesses, ridges, serrations, knurlings,
spikes, or roughened surfaces for engaging the endplates of the
adjacent vertebrae. Leading end portion 316 can include a rounded
or tapered configuration so that body 312 is provided with a
leading end nose that distracts the adjacent vertebrae as it is
inserted in a collapsed disc space. Body 312 also includes a
proximal trailing end wall 321, and sidewalls 313, 315 extending
between proximal end wall 321 and leading end portion 316. A first
notch 324 in lateral wall 313 and a second notch 326 in lateral
wall 315 open proximally at proximal end wall 321, and extend
distally into trailing end portion 311.
[0112] Proximal end wall 321 includes a bore 328 formed therein to
facilitate engagement with an insertion tool. Bore 328 can be a
circular bore, and can be threaded therealong for engagement with a
threaded post of an insertion instrument. Bore 328 includes a
flared proximal end opening 330 to facilitate placement of the
insertion instrument into bore 328. Other embodiments contemplate
that bore 328 can be smooth and unthreaded. Still further
embodiments contemplate bore 328 is non-circular. Also contemplated
are implants 310 without bore 328, or with multiple bores 328.
[0113] Implant 310 includes a cavity 332 extending between and
opening at upper surface 314 and lower surface 317. Cavity 332 is
enclosed by sidewalls 313, 315, leading end portion 316, and
trailing end portion 311. Sidewalls 313, 315 include holes 318,
320, respectively, extending therethrough and in communication with
cavity 332. Holes 318, 320 include a circular shape, although other
shapes and numbers of holes are contemplated in sidewalls 313, 315.
Cavity 332 includes an oval or racetrack shape when viewed from one
of the upper and lower surfaces 314, 317 as shown in FIG. 32. The
inner wall surfaces of sidewalls 313, 315 extend parallel to one
another, and the inner wall surfaces of leading end portion 316 and
trailing end portion 311 are radiused and extend between the inner
surfaces of sidewalls 313, 315.
[0114] Engagement members 334, 344 extend along the sidewalls 313,
315, and project from respective ones of the upper and lower
surfaces 314, 317. Engagement surfaces 334, 344 extend along the
portions of sidewalls 313, 315 extending along cavity 332. Upper
and lower surfaces 314, 317 include a smooth surface profile along
leading end portion 316 and trailing end portion 311. Accordingly,
engagement surfaces 334, 344 are optimally positioned along the
convexly curved upper and lower implant surfaces for engagement
with the softer bony material near the center of the vertebral
endplates to resist backout of implant 310. Also, the smooth
surface profiles at the leading and trailing ends maximize the
bearing surface area of implant 310 at the portions of the upper
and lower surfaces 314, 317 adjacent the harder bone material at
the cortical rim. This enhances the maintenance of distraction and
resistance to post-operative settling of the adjacent vertebra when
implant 310 is positioned in the spinal disc space.
[0115] In one form, engagement members 334, 344 are in the form of
teeth, and include a sloped leading end wall 316, a generally
vertical trailing end wall 338, and a transition surface 340
extending therebetween, as shown in FIG. 33. A groove or recess 342
extends between adjacent ones of the teeth. The teeth project a
distance 350 from the respective upper or lower surface 314, 317.
In one form, upper and lower surface 314, 317 extend along an arc
defined by radius 350, and engagement surfaces 334, 344 extend
along an arc defined by radius 352, with radius 352 being greater
than radius 350. The adjacent teeth are separated by a spacing 354
measured between adjacent trailing end walls 338. To maintain the
orthogonal orientation of the teeth spaced along the arc formed by
radius 350, trailing end walls 338 is oriented at an angle 356
relative to one another. Trailing end walls 338 are perpendicular
to the arc formed by radius 350, and leading end wall 336 forms an
angle 358 with trailing end wall 338. In one specific embodiment,
radius 352 is 1 millimeter greater than radius 350, and spacing 354
is 3 millimeters. Angle 358 can range from 0 degrees to 90 degrees
in one embodiment; in another embodiment angle 358 ranges from 30
degrees to 80 degrees; in a further embodiment angle 350 ranges
from 50 degrees to 80 degrees; and in still another embodiment
angle 358 is 65 degrees. It should be understood however that other
radii, spacing and angles are contemplated.
[0116] Implant 310 can be provided in a kit with a number of
implants having various heights and/or lengths from which a surgeon
can select during surgery to provide a desired fit of the implant
in the spinal disc space. It is contemplated that each implant is
provided with a width 360. In one form, the width 360 is the same
for each implant in the kit. In a further form, each implant 310
includes a leading end nose that includes a distally oriented,
rounded or radiused leading end profile to facilitate insertion in
a non-distracted or partially distracted disc space. In still
another embodiment, a number of implants 310 are provided in a kit
with a number of distractors that include a head corresponding in
size and shape to corresponding ones of the implant 310. As
discussed above, the distractors can include a head integrally
attached to a shaft or removably attached to a shaft.
[0117] It is further contemplated that implant 310 includes cavity
332 that provides a maximum surface area opening through implant
310 for bone growth through the implant. In one embodiment, cavity
332 includes a width that extends across more than 50 percent of
the width 260 of implant 310. In another embodiment, cavity 332
includes a width that extends across more than about 60 percent of
width 360 of implant 310. In still another form, cavity 332 extends
along more than 50 percent of the length of implant 310 along axis
319.
[0118] Any suitable osteogenetic or osteoinductive material or
composition is contemplated for placement within cavities of any of
the implant embodiments discussed herein. Such material includes,
for example, autograft, allograft, xenograft, demineralized bone,
synthetic and natural bone graft substitutes, such as bioceramics
and polymers, and osteoinductive factors. Where bony material is
placed within the implant cavity, the material can be pre-packed
into the cavity before the device is implanted. A separate carrier
to hold the materials within the cavities of the implants can also
be used. These carriers can include collagen-based carriers,
bioceramic materials, such as BIOGLASS.RTM., hydroxyapatite and
calcium phosphate compositions. The carrier material can be
provided in the form of a sponge, a block, folded sheet, putty,
paste, graft material or other suitable form. Moreover, the
osteogenetic compositions contained within the implants can
comprise an effective amount of a bone morphogenetic protein,
transforming growth factor .beta.1, insulin-like growth factor 1,
platelet-derived growth factor, fibroblast growth factor, LIM
mineralization protein (LMP), and combinations thereof or other
therapeutic or infection resistant agent, held within a suitable
carrier material.
[0119] Referring to FIG. 34, there is shown another embodiment
implant 410. Implant 410 is similar to implant 310, and includes a
leading end portion 416 and an opposite trailing end portion 411.
Implant 410 includes convexly curved upper surface 414 and an
opposite convexly curved lower surface. A first sidewall 413 and
opposite parallel sidewall extend between leading end portion 416
and trailing end portion 411. The trailing or proximal end wall can
include a bore as discussed above with respect to implant 310.
Implant 410 can also be provided without a bore in its trailing end
wall. A pair of opposite notches (only notch 424 is shown) are
provided in sidewalls 313, 315 to facilitate engagement with an
insertion instrument as discussed above with respect to implant
310. In contrast to the illustrated implant 310, implant 410
includes a solid body and smooth surface profile along its upper
and lower surfaces to maximize the bearing surface area support. In
addition, leading end portion 416 includes a nose with a leading
end surface profile rounded between the sidewalls along an arc
defined by a radius 420. The surface profile of the nose is also
rounded between the upper and lower surfaces of implant 410. The
leading end nose surface profiles can be formed by multiple curved
segments having differing radii, and also include one or more
linear segments.
[0120] The rounding of leading end portion 416 medially-laterally
between sidewalls 413, 415 facilitates placement of implant 410
through the tissue in the approach to the disc space. For example,
the rounded nose eliminates any abrupt comers at the leading end of
the implant. Neural structures and other tissue can be pushed out
of the insertion path of the implant due to the smooth surface
profile. The rounding of the leading end nose bi-directionally,
i.e. between the sidewalls and between the upper and lower surfaces
of the implant, facilitates placement of implant 410 in a small
opening in the annulus tissue by both distracting the adjacent
vertebrae and separating the annulus tissue to form an opening of
sufficient yet minimized size to accommodate placement of implant
410. Still further, when the implant is positioned in the disc
space, the leading end nose can more easily be positioned at the
cortical rim of the endplates at the far end of the disc space.
There are no abrupt edges or transitions which may embed or catch
on the cortical rim at its transition with the concavely curved
region of the vertebral endplates, facilitating final positioning
of implant 410 in the disc space.
[0121] Implant 410 can be provided with holes in its sidewalls,
such as is shown with holes 420, 422. The sidewall holes provide an
avenue for bone ingrowth into implant 410, enhancing its anchoring
in the disc space during fusion. In the illustrated embodiment, two
holes are provided, although more than two holes or less than two
holes are contemplated. The holes can include a blind end in
implant 410, or can extend completely through implant 410 in
communication with an opening in the opposite sidewall. Other
embodiments contemplate that the sidewalls are provided without
holes.
[0122] Referring to FIG. 35, there is shown another embodiment
implant 510. Implant 510 is similar to implant 410, and includes a
leading end portion 516 and an opposite trailing end portion 511.
Implant 510 includes convexly curved upper surface 514 and an
opposite convexly curved lower surface. A first sidewall 526 and
opposite parallel sidewall 528 extend between leading end portion
516 and trailing end portion 511. The trailing or proximal end wall
can include a bore and/or notches 524 to facilitate engagement with
an insertion instrument. Implant 510 further includes a cavity 532
extending between and opening at the upper and lower surfaces
thereof. Sidewalls 526, 528 include holes 518, 520, respectively,
in communication with central cavity 532.
[0123] In contrast to the illustrated implant 310, implant 510
includes a smooth surface profile along its upper and lower
surfaces, including the portions along cavity 532. In addition,
leading end portion 516 includes a nose rounded about a radius 512
between the sidewalls, and also rounded between the upper and lower
surfaces, as discussed above with respect to implant 410.
[0124] Referring to FIG. 36, there is shown an insertion instrument
550. Insertion instrument 550 includes an elongated shaft 552
extending between a proximal portion 554 and a distal gripping
portion 556 which serves as a coupling member to couple the implant
to shaft 552. Proximal portion 554 includes a handle 558 extending
transversely to shaft 552. In one embodiment, handle 558 is
obliquely oriented to shaft 552 to facilitate manipulation and
gesturing with insertion instrument 550. Shaft 552 projects
proximally from handle 558 to a housing portion 560. Housing
portion 560 includes an adjustment member 562 housed therein. An
inner shaft 564 (FIG. 37) extends distally from adjustment member
562 and through shaft 552 to distal gripping portion 556.
Adjustment member 562 provides a thumbwheel or other suitable
gripping element to facilitate the surgeon rotating inner shaft 564
within outer shaft 552 for engagement of the distal end of inner
shaft 564 with an implant.
[0125] Distal gripping portion 556 includes body member 566 and a
pair of finger 568, 570 extending distally from opposite sides of
body member 566. The distal end of inner shaft 564 projects
distally from body member 566 and is centrally located between
fingers 568, 570. As shown in FIG. 38, fingers 568, 570 are
positionable in respective ones of the notches of the implant to
which insertion instrument 550 is engaged, such as implant 310 in
the illustrated embodiment. Inner shaft 564 is engageable in the
bore in the proximal end wall of implant, such as bore 328 of
implant 310. The outer surfaces of fingers 568, 570 are flush or
recessed relative to the outer lateral surfaces of sidewalls of the
implant such that fingers 568, 570 do not protrude therefrom. When
engaged to the implant, fingers 568, 570 define an overall width
that is less than the width of the implant between the outer
lateral surfaces of its sidewalls. This minimizes the insertion
profile of the implant and instrument assembly, and facilitates a
less invasive approach to the spinal disc space.
[0126] Referring to FIG. 39, there is shown another embodiment
insertion instrument 580. Insertion instrument 580 includes an
outer shaft 582 longitudinally movable about an inner shaft 584.
Insertion instrument 580 includes a distal gripping portion 586
which forms a coupling member for coupling an implant to inner
shaft 584. Distal gripping portion 586 includes a body member at a
distal end of inner shaft 584 that includes a base portion 598 and
a pair of biasing members 588, 590 separated by a central slot 596.
Biasing members 588, 590 are coupled to one another about a living
or integral hinge formed at base portion 598. Fingers 592, 594
extend distally from respective ones of the biasing members 588,
590. Base portion 598 includes a proximally tapered outer surface
profile. Outer shaft 582 is movable distally relative to inner
shaft 584 and along the outer surface profile of at least base
portion 598 to move biasing members 588, 590 and thus fingers 592,
594 toward one another to grip an implant therebetween. The implant
can be released by proximally displacing outer shaft 582 relative
to inner shaft 584 to allow biasing members 588, 590 and thus
fingers 592, 594 to move away from one another toward their normal
state.
[0127] Various mechanisms for moving outer shaft 582, 584 are
contemplated. For example, shafts 582, 584 can be threadingly
engaged to one another and outer shaft 584 is rotated about inner
shaft 582 to effect proximal and distal movement therebetween. In
another example, proximal handle actuators are coupled to inner and
outer shaft 582, 584, and the handles effect proximal and distal
linear movement between the shafts as the handles are manipulated.
Other suitable mechanisms for moving the inner and outer shafts
longitudinally relative to one another are also contemplated.
[0128] The present invention contemplates various procedures and
instrument sets. For example, the surgeon can determine whether a
trial body or implant provides a desired disc space height by
tactile feedback of the inserted trial body or implant, and also by
visual inspection. The inserted trial body or implant body should
sufficiently stretch the remaining annulus tissue to provide firm
engagement between the upper and lower surfaces of the trial or
implant body and the adjacent vertebral endplates. Sufficient
surface area contact should be present to prevent or minimize
post-operative movement of the adjacent vertebrae relative to the
implant. By providing the trial bodies and implant bodies with
correspondingly sized and shaped leading end portions, and by
inserting the trial bodies and implant bodies in a non-distracted
disc space, the inserted trial or implant body provides immediate
feedback to the surgeon of the desirability of the fit. If
distraction were maintained by, for example, a second distractor,
feedback to the surgeon of the post-operative fit of the implant
would not be reliable or available, if at all, until distraction
were removed. As such, the trial bodies and implants can be
employed without utilization of external distraction or distraction
maintained in another disc space location during trial body and
implant insertion. However, secondary distraction can be used to at
least partially maintain disc space distraction upon withdrawal of
the implants and trial bodies can be employed. For example, pedicle
screws and a rod can be employed on the contralateral side to at
least partially maintain distraction obtained with a particular
implant or trial body; however, use of the same is not
required.
[0129] Further, the trial bodies provide an indication of the fit
of the implant into the disc space location. Since the implant
includes a leading end portion and height that corresponds to that
of the trial body, there is an immediate confirmation to the
surgeon that the corresponding implant will fit into the space
occupied by the trial body. If distraction were maintained at
another location in the disc space or externally, there is no
indication that the implant will fit properly until the implant is
inserted and distraction removed. As a result, the implant may
wedge too tightly in the disc space when distraction is removed,
making subsequent removal of the implant difficult if an
appropriate fit is not obtained. Alternatively, the implant may be
too loose when the distraction is removed due to over distraction
of the disc space.
[0130] The implants can be impacted or pushed into the disc space.
As a result, disruption to the annulus tissue and tissue
approaching the collapsed disc space is minimized since the lateral
and vertical footprint of the implant in the disc space can be the
same as the lateral and vertical footprint occupied in the
implant's approach to the disc space. Also, by providing the
implant with the same footprint as the trial body laterally and
vertically, and by performing distraction and implant insertion
through the same portal or pathway, no additional tissue dissection
and/or retraction is required to accommodate distraction of the
disc space during implant insertion.
[0131] The trial bodies and implants can be inserted into the disc
space with minimal disc space preparation. According to one method,
the collapsed disc space is accessed, and an opening is formed in
the annulus having a width corresponding to the width of the trial
bodies and/or implants. Disc material is removed through the
annulus opening, and, if desired by the surgeon, manual roughening
of the endplates is performed with a scraper or other suitable
endplate roughening instrument. The trial bodies and/or implant
bodies are then sequentially inserted and, if necessary, withdrawn
through the annulus opening and into the disc space. Since the
implants are self-distracting, it is not necessary to chisel, drill
or otherwise form the vertebral endplates to receive the implant,
although such steps are not precluded. Consequently, fewer steps in
the surgical procedure are necessary since requirements for
bilateral distraction, external distraction, chiseling, drilling
and reaming are eliminated. In addition, the lack of other
instruments or devices in the disc space facilitates visualization
of the disc space preparation, trial body insertion, and/or implant
insertion. Elimination of cutting instruments in the disc space
also theoretically improves the safety of the procedure.
[0132] Minimally invasive techniques employing the trial
instruments and implants are contemplated. In any particular
patient, the implants can be inserted via any one or combination of
posterior, postero-lateral, antero-lateral, transforaminal, far
lateral and/or anterior approaches. Implant insertion can occur
through a single pathway to a collapsed spinal disc space, or
through multiple pathways to the collapsed disc space, or through
multiple pathways to multiple levels of collapsed discs of the
spinal column. Since the implant, and trial instruments if
employed, are inserted into the same disc space location from the
same approach, the entire procedure for inserting an implant can be
completed through one pathway. If a multiple pathway procedure is
to be employed, the surgeon can complete implant insertion through
one pathway before creating and moving to work in a second
pathway.
[0133] Since distraction and implant insertion occur along the same
pathway to the collapsed disc space, the implants and trial
instruments are suited for use in minimally invasive procedures
which employ a retractor sleeve to provide a pathway to the
collapsed disc space. Such retractor sleeves can employ any one or
combination of an endoscopic viewing element in the working
channel, a microscopic viewing system over the proximal end of the
retractor sleeve, fluoroscopic viewing, loupes, naked eye and/or
image guidance.
[0134] The trial bodies of the trial instruments and the implant
bodies can be made from any biocompatible material, including
synthetic or natural autograft, allograft or xenograft tissues, and
can be resorbable or non-resorbable in nature. Examples of tissue
materials include hard tissues, connective tissues, demineralized
bone matrix and combinations thereof. Further examples of
resorbable materials are polylactide, polyglycolide,
tyrosine-derived polycarbonate, polyanhydride, polyorthoester,
polyphosphazene, calcium phosphate, hydroxyapatite, bioactive
glass, and combinations thereof. Further examples of non-resorbable
materials are non-reinforced polymers, carbon-reinforced polymer
composites, PEEK and PEEK composites, shape-memory alloys,
titanium, titanium alloys, cobalt chrome alloys, stainless steel,
ceramics and combinations thereof and others as well. If the trial
body or implant is made from radiolucent material, radiographic
markers can be located on the trial body or implant to provide the
ability to monitor and determine radiographically or
fluoroscopically the location of the body in the spinal disc space.
The material comprising the trial bodies can be solid, porous,
spongy, perforated, drilled, and/or open.
[0135] There is contemplated an implant for insertion into a spinal
disc space between adjacent vertebrae. The implant can be impacted
or pushed into the disc space. The implant can be provided with a
distal end or leading insertion end that is sized for insertion
into the collapsed disc space. As the implant is inserted, the
implant can restore the collapsed disc space to a desired disc
space height. The desired disc space height corresponds to the
height of the implant proximal the distal end. Once inserted, the
implant can maintain the disc space at the desired disc space
height.
[0136] There is further contemplated an implant that, when
inserted, restores and maintains a desired disc space height of a
collapsed disc space between an upper vertebra and a lower
vertebra. The implant includes a body with a distal end, a proximal
end, an upper surface orientable toward an endplate of the upper
vertebra and a lower surface orientable toward an endplate of the
lower vertebra. The body of the implant has a first height between
the upper and lower surfaces corresponding to the desired disc
space height. The body of the implant also has a second height at
its distal end that is less than a height of the collapsed disc
space.
[0137] It is contemplated that the implants can be provided with
bi-convex curvature of the upper and lower surfaces, allowing the
implants to center in the endplates of the disc space. It is
further contemplated that the upper and lower surfaces of the
implant can be planar or include compound geometry. The upper and
lower surfaces of the implant can also be configured to establish
lordotic or kyphotic angulation between the adjacent vertebral
bodies.
[0138] Also contemplated is a set of implants having two or more
implants of increasing height. The height of each implant
corresponds to a restored disc space height. The leading insertion
end of each implant is sized for insertion into a collapsed disc
space. As each implant is inserted, the implant restores the
collapsed disc space to the restored disc space height provided by
the inserted implant. If the restored disc space height does not
correspond to the desired disc space height, the inserted implant
is withdrawn and a larger height implant is inserted. Sequential
insertion and withdrawal of increasing height implants is continued
until the restored disc space height provided by an implant of the
set of implants corresponds to the desired disc space height. The
implant providing the desired disc space height is positioned in
the disc space to restore and post-operatively maintain the desired
disc space height.
[0139] There is further contemplated an instrument set having two
or more self-distracting trial instruments and at least one
implant. The two or more trial instruments each have a body with a
leading insertion end sized for insertion into a collapsed disc
space. The leading insertion ends of each trial body are
substantially the same in size and shape. Each trial body has a
height proximal the leading insertion end that restores the
collapsed disc space height to a height different than that of the
other trial bodies. The at least one implant has a leading
insertion end that is substantially the same in size and shape as
the leading insertion end of at least one of the trial bodies of
the trial instruments. The implant has a height proximal its
leading insertion end that corresponds to the desired restored disc
space height provided by the at least one trial body.
[0140] Also contemplated is a kit including a set of trial
instruments, each having a trial body at a distal end thereof. The
trial bodies have a self-distracting leading end portion insertable
in a collapsed spinal disc space. The kit further includes a set of
implants positionable in the collapsed spinal disc space. Each
implant has a body sized and shaped to correspond in size and shape
to a respective trial body of the trial instruments. The fit of
each implant body in the spinal disc space is indicated to the
surgeon by the fit of the corresponding trial body of the trial
instruments. When a trial body provides a desired fit, the trial
body is removed and the implant corresponding to the trial body is
inserted into the collapsed disc space in the location previously
occupied by the withdrawn trial body.
[0141] It is contemplated that an insertion instrument can be
engaged to lateral walls of an intervertebral implant. The
insertion instrument includes a distal coupling portion
positionable in notches formed in corresponding ones of the lateral
walls of the implant. The coupling portion has a first position
engaging the implant in the notches and a second position
disengaged from the implant in the notches. The width of the
coupling portion in each of its first and second positions is less
than the width of the implant between the lateral walls of the
implant.
[0142] Methods for inserting an intervertebral implant into a
collapsed spinal disc space are also contemplated. A number of
implants are sequentially inserted into the collapsed disc space to
restore the disc space. If a particular implant does not restore
the disc space to a desired disc space height, the implant is
withdrawn from the disc space. When an inserted implant is
withdrawn, the disc space is non-distracted and allowed to
collapse. The implant providing the desired disc space height
remains in the disc space to post-operatively maintain the desired
disc space height.
[0143] A method is contemplated for inserting an intervertebral
implant that includes accessing a collapsed spinal disc space from
an uni-portal approach. A first implant is inserted through the
portal into the disc space to restore the disc space height. If the
restored disc space height does not correspond to a desired disc
space height, the inserted implant is removed from the disc space
and portal, and the disc space is allowed to collapse. A second
implant of different height is inserted into the undistracted,
collapsed disc space to provide another restored disc space height.
When an inserted implant provides a restored disc space height that
corresponds to a desired disc space height, the inserted implant
remains in the disc space to post-operatively maintain the desired
disc space height.
[0144] Also contemplated is a method for inserting an
intervertebral implant is provided that includes accessing a
collapsed spinal disc space. A number of trial bodies are provided
with leading end portions sized for insertion into a non-distracted
disc space. The trial bodies are sequentially inserted into and
removed from the disc space. The trial body providing the desired
disc space height is used to select an implant having a height and
a self-distracting leading end portion corresponding to the height
and leading end portion of the last inserted trial body. The
implant is then inserted into the non-distracted disc space to
restore the disc space and post-operatively maintain the desired
disc space height.
[0145] While the invention has been illustrated and described in
detail in the drawings and foregoing description, the same is to be
considered as illustrative and not restrictive in character, and
that all changes and modifications that come within the spirit of
the invention are desired to be protected.
* * * * *