U.S. patent application number 15/810253 was filed with the patent office on 2018-03-08 for expandable interbody implant.
The applicant listed for this patent is Nicholas Poulos. Invention is credited to Nicholas Poulos.
Application Number | 20180064555 15/810253 |
Document ID | / |
Family ID | 48744439 |
Filed Date | 2018-03-08 |
United States Patent
Application |
20180064555 |
Kind Code |
A1 |
Poulos; Nicholas |
March 8, 2018 |
EXPANDABLE INTERBODY IMPLANT
Abstract
An intervertebral implant that can be surgically introduced
between adjacent vertebrae and expanded in situ to occupy an
optimal space between the vertebrae. The implant is inserted into
the evacuated disc space obliquely and then oriented so as to
extend laterally across the anterior adjacent vertebrae with its
outer ends of the implant supported by the cortical rims on the
opposite sides of the vertebrae. The implant has two body members
with a space therebetween so the implant may be then distracted and
a spacer of predetermined thickness that may be inserted within the
space between the body members so as to maintain a desired amount
of distraction. The upper and lower surfaces of the implant may
have a desired lordotic angle. A method of using an implant is
disclosed which permits endoscopic visualization of the disc
space.
Inventors: |
Poulos; Nicholas;
(Belleville, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Poulos; Nicholas |
Belleville |
IL |
US |
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|
Family ID: |
48744439 |
Appl. No.: |
15/810253 |
Filed: |
November 13, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14966604 |
Dec 11, 2015 |
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15810253 |
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14520892 |
Oct 22, 2014 |
9211195 |
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14966604 |
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|
13543126 |
Jul 6, 2012 |
8906099 |
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14520892 |
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12899625 |
Oct 7, 2010 |
9180017 |
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13543126 |
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13030618 |
Feb 18, 2011 |
8480748 |
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12899625 |
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61610198 |
Mar 13, 2012 |
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61356851 |
Jun 21, 2010 |
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61251002 |
Oct 13, 2009 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 2/4465 20130101;
A61F 2002/30565 20130101; A61F 2002/30593 20130101; A61F 2002/30736
20130101; A61F 2310/00017 20130101; A61F 2002/3008 20130101; A61F
2002/30556 20130101; A61F 2002/30616 20130101; A61F 2/4611
20130101; A61F 2/447 20130101; A61F 2002/30357 20130101; A61F
2002/30594 20130101; A61F 2/442 20130101; A61F 2002/305 20130101;
A61F 2310/00131 20130101; A61F 2002/30579 20130101; A61F 2310/00023
20130101; A61F 2002/30784 20130101; A61B 17/025 20130101; A61F
2002/30518 20130101; A61F 2002/30607 20130101; A61F 2220/0033
20130101; A61B 2017/00261 20130101; A61B 2017/0256 20130101; A61F
2002/30604 20130101; A61F 2/4455 20130101; A61F 2/4684
20130101 |
International
Class: |
A61F 2/44 20060101
A61F002/44; A61B 17/02 20060101 A61B017/02; A61F 2/46 20060101
A61F002/46 |
Claims
1. An expandable spinal implant for insertion in a disc space
between two adjacent vertebrae bodies to be fused together by bone
graft material placed in said disc space, said vertebrae bodies
each having a cortical rim and an end plate within said cortical
rim, said disc space being substantially defined by an annulus
attached to said adjacent vertebrae bodies and by the endplates of
said adjacent vertebrae bodies, said implant comprising an elongate
body having a height and a width such that said implant may be
inserted into the disc space through an incision in a posterior
portion of the annulus, said implant having a length such that with
said implant positioned within said disc space the implant may be
oriented to extend across the disc space so that said implant is at
least in part supported on said cortical rim of at least one of
said vertebrae bodies, said implant having a lower body member and
an upper body member each of which is adapted to be cooperable with
a distractor for distraction of said body members while said
implant is within said disc space so as to effect distraction of
said disc space, said implant further comprising a spacer
insertable into said disc space through said incision in said
annulus and to be positioned between said upper and lower body
members while the upper and lower body members are distracted
within said disc space such that said implant with said spacer
installed between said upper and lower body members is configured
to maintain distraction of said disc space a desired amount.
2. An implant as set forth in claim 1 wherein said implant has a
first end and a second end, and wherein said implant is of such a
length that with its first end at least partially received in a
first opening in an anterior portion of said annulus generally
opposite said incision, and with said implant oriented to extend
across said vertebrae bodies and with the second end of said
implant at least partially received in a second opening in an
anterior portion of said annulus generally opposite said first
opening, said implant is at least in part supported on at least one
of said cortical rims.
3. An implant as set forth in claim 1 wherein one of said body
members has an inner surface and a pair of stabilizing posts
extending from said inner surface and the other of said body
members has a pair of bores for receiving said stabilizing posts,
said posts and said bores being configured to maintain said body
members in desired relation to one another and yet permitting
distraction and retraction of the body members relative to one
another.
4. An implant as set forth in claim 3 wherein each said bore has a
sliding axial fit relative to its respective said post so as to aid
in stabilizing said body members relative to one another and so as
to permit distraction and retraction of said body members relative
to one another.
5. An implant as set forth in claim 1 wherein said implant is
configured to be supported on said one cortical rim at two or more
locations spaced from one another.
6. A spinal implant for insertion in a disc space between two
adjacent vertebrae bodies, said disc space being defined by an
annulus attached to said adjacent vertebrae bodies, each of said
vertebrae bodies having a cortical rim and an endplate within its
cortical rim, said implant comprising an elongate body configured
to be inserted within the disc space through an incision in a
posterolateral portion of said annulus, said implant having a
length, a first end, and a second end such that with said first end
of the implant being at least partially received in a first opening
formed in an anterior portion of the annulus, said implant may be
oriented within said disc space so that with said first end
received in said first opening said first end is supported on one
of said cortical rims proximate said first opening and so that with
said implant extending generally laterally of said vertebrae bodies
with its second end being at least partially received within a
second opening in said annulus generally opposite said first
opening said implant being least in part supported on the one
cortical rim, said implant having a lower body member and an upper
body member, each of said body members being configured to be
cooperable with a distractor so that upon operation of said
distractor said body members are forced apart so as to in turn
distract the disc space, said implant further comprising a spacer
of a predetermined thickness adapted to be inserted through said
incision into said disc space and positioned between said upper and
lower body members while said body members are distracted so as to
substantially maintain a desired amount of distraction of said disc
space.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] "This application is a continuation application of and
claims priority to co-pending application Ser. No. 14/966,604 filed
Dec. 11, 2015, which is a continuation of application Ser. No.
14/520,892, filed Oct. 22, 2014 now U.S. Pat. No. 9,211,195, which
is a continuation of application Ser. No. 13/543,126 filed Jul. 6,
2012, now U.S. Pat. No. 8,906,099, which is a continuation-in-part
of application Ser. No. 12/899,625 filed Oct. 7, 2010, now U.S.
Pat. No. 9,180,017 and continuation-in-part of application Ser. No.
13/030,618 filed Feb. 18, 2011, now U.S. Pat. No. 8,480,748.
Application Ser. No. 13/543,126 also claims priority to U.S.
Provisional Application No. 61/610,198 filed Mar. 13, 2012.
Application Ser. No. 12/899,624 claims priority to Provisional
Application 61/356,851 filed Jun. 21, 2010 and Provisional
Application No. 61/251,002 filed Oct. 13, 2009. All of the
foregoing prior applications are incorporated herein by reference
in their entirety."
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not Applicable.
BACKGROUND OF THE DISCLOSURE
[0003] This disclosure relates to intervertebral disc prostheses,
and more particularly to an intervertebral disc prosthesis that can
be surgically introduced between adjacent vertebral bodies,
preferably between lumbar vertebrae, and adjusted or expanded in
situ to occupy an optimal or desired space between the vertebral
bodies.
[0004] In recent years, surgical procedures have been developed in
which two or more vertebrae are joined or fused together. Such
procedures are now common in the treatment of spinal disorders such
as spondylolisthesis, scoliosis, and disc degeneration. Certain of
these fusion surgeries include Posterior Lumbar Interbody Fusion
(PLIF), Transforaminal Lumbar Interbody Fusion (TLIF), Anterior
Lumbar Interbody Fusion (ALIF), and DLIF (Direct Lateral Interbody
Fusion). These procedures are well known to spinal surgeons.
[0005] Interbody vertebral spacers are known that are inserted
between the vertebrae bodies to replace a collapsed, degenerated,
or unstable disc. However, these prior spacers were typically of a
predetermined thickness and thus it was difficult to size the
thickness of the spacer to result in the desired amount of
distraction between the vertebrae bodies in order to achieve the
desired amount of distraction between the adjacent vertebra bodies.
Such prior spacers are commercially available from Stryker Spine of
Mahwah, N.J., from Medtronic, Spinal and Biologics Business,
Memphis, Tenn., from Spinal Concepts, Inc. of Austin Tex., and from
NuVasive, Inc. of San Diego, Calif.
[0006] Certain adjustable height interbody fusion devices are
known, such as described in U.S. Pat. No. 6,080,193 that vary the
distance between the portions of the spacer that engage the
endplates of the adjacent vertebrae. However, these adjustable
fusion devices rely on cams and other complicated mechanisms for
adjustment purposes.
[0007] In general, lordosis is the curvature of the spine with the
convexity forward. Lordosis is not necessarily a disease state, but
rather the normal anterior physiologic curve of the neck or low
back. This disclosure is primarily concerned with lumbar lordosis.
Most lumbar disc spaces in healthy spines are generally parallel or
nearly 0 degree lordotic, and is particularly true for L1/2, L2/3,
and L3/4 However, the L4/5 may have a lordotic angle ranging
between about 0.degree.-12.degree., and L5/S1 may also range
between about 0.degree.-12.degree.. Therefore, in reconstructing a
disc space that has some lordosis it would be advantageous to have
an implant matching the existing anatomy so that the two surfaces
of the implant would better conform to and better fit the shape of
the disc space so that load sharing occurs over the whole implant.
Otherwise, an implant having parallel upper and lower surfaces used
in a disc space having, for example, 8 degrees of in situ lordosis
would result in only part of the implant contacting its respective
vertebrae bodies and thereby lessening the corrective support
applied to the spine and thus predisposing the implant to
subsidence. That is, subsidence refers to an increased tendency of
the implant, over time, to telescope, settle or project into the
adjacent vertebrae bodies with loss disc space height back to
preoperative levels. When using conventional implants, it is
frequently observed that such telescoping or settling occurs with
such implants placed wholly within the disc space, rather than
having the implant bearing on and distracting from the cortical
rim/apophyseal ring of the adjacent vertebrae as disclosed in my
Co-pending U.S. patent application Ser. No. 12/899,625, now U.S.
Pat. No. 9,180,017. Additionally, a more conformal fit in a disc
space with lordosis will allow more uniform distribution of
corrective forces applied during distraction. Thus, it would be
desirable to provide an expandable (variable height) implant, as
described in my above-noted pending application that would provide
options for encountered or desired disc space lordosis. It would
also be desirable to use either a variable or a fixed height
implant that could reconstruct any disc space anatomy or morphology
surgically encountered including lordotic conditions with the
surgical procedures described in my above-identified U.S. Patent
application and patents in the present disclosure.
SUMMARY OF THE DISCLOSURE
[0008] The present disclosure relates to an intervertebral disc
prostheses, and more particularly to an intervertebral disc
prosthesis that can be surgically introduced between adjacent
vertebral bodies, preferably between lumbar vertebrae, and adjusted
or expanded in situ to occupy an optimal or desired space between
the vertebral bodies. The implant is preferably inserted into the
evacuated disc space obliquely and then oriented so as to extend
laterally across the adjacent vertebrae bodies anteriorly occupying
the disc space with the outer ends of the implant being supported
at least in part by the cortical rims on opposite sides of the
adjacent vertebrae bodies. The outer convex surfaces of the two
body members conform anatomically to the shape of the disc space
contacting the endplates. The implant has two body members that are
movable relative to one another so as to vary the space between the
members. With the implant so positioned and oriented, the implant
and thus the disc space may be then distracted and a spacer of a
desired, predetermined thickness may be inserted within the space
between the body members so as to maintain a desired amount of
distraction.
[0009] Still further, the present disclosure relates to such an
expandable (variable height) or non-expandable (fixed height) disc
prosthesis that may have angled upper and lower surfaces engageable
with the adjacent vertebrae bodies so as to introduce a
predetermined degree of lordosis thereby to better reconstruct the
spine by introducing segmental lordosis and improving regional
lordosis and global sagittal balance. It is also understood that
0.degree. or parallel surfaced implants maybe an appropriate choice
dictated by intraoperative findings and surgical anatomy.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a lateral view of a series of lumbar vertebrae (or
vertebrae bodies) illustrating intervertebral cartilage discs
between adjacent vertebrae, and further illustrating an opening in
a posterior lateral quadrant of the annulus for the insertion of an
expandable lumbar disc replacement implant or prosthesis of the
present disclosure within the disc space between adjacent vertebrae
so as to maintain the adjacent vertebrae in a desired distracted
position;
[0011] FIG. 2 is a median sagittal cross section of one of two
adjacent lumbar vertebrae and the annulus between such adjacent
vertebrae illustrating the desired position of the lumbar disc
replacement implant within the disc space;
[0012] FIG. 3 is a side elevational view of a lumbar vertebrae
illustrating the lateral placement of the implant on the upper
surface of the cortical rim of the lower vertebrae body;
[0013] FIG. 4 is an axial inferior view of a lumbar vertebrae
(e.g., L4) illustrating the implant of the present disclosure which
is initially inserted obliquely through an incision in the annulus
and received in a first opening generally opposite the incision and
in a second opening generally across from the first opening with
the implant oriented to extend across the vertebrae bodies and to
span from one side to the other of the vertebrae bodies and to bear
against the cortical rims of the upper and lower vertebrae bodies
and contacting the interposed endplate, where this view further
illustrates an oblique slot in the inner faces of the upper and
lower implant body members so as to permit a surgical instrument
(e.g., a parallel distractor, such as shown in FIGS. 66-70) to be
inserted in these slots to distract the expandable implant and the
disc space;
[0014] FIG. 4A is a view similar to FIG. 4 of the spine
illustrating a minimally invasive TLIF exposure dissecting between
the fascial planes of the multifidus and longisimus muscles with an
operative tube seated on the bony anatomy of the spine;
[0015] FIG. 4B illustrates lumbar vertebrae L3, L4 and L5 with a
unilateral exposure of the operating site between vertebrae L3 and
L4;
[0016] FIG. 4C is a posterior view of the operating site on a
somewhat enlarged scale;
[0017] FIG. 4D is a view similar to FIG. 4 illustrating the
incision and the first and second openings in the annulus without
the implant of this disclosure installed;
[0018] FIG. 4E is a view similar to FIG. 4D, but where the incision
and the second opening are, respectively, posterior and anterior
portions of a single elongate annulotomy and where the first
opening is the anterior portion of another elongate annulotomy,
where the elongate annulotomies help relax the annulus;
[0019] FIG. 4F is a diagrammatic axial depiction of a vertebrae (or
vertebrae body), the annulus, the disc space, and other major
anatomical features of the vertebrae illustrating the location of
the incision and the openings made in the annulus in accordance
with the procedure shown in FIGS. 4 and 4D;
[0020] FIG. 4G is a view similar to FIG. 4F illustrating the
location of the openings made in the annulus in accordance with the
procedure of this disclosure, as shown in FIG. 4E, such that there
is sufficient room to insert an endoscopic light delivery system
and lens viewing system and also to accommodate surgical
instruments for performing endoscopic discectomy;
[0021] FIG. 4H is a view if a vertebrae and the annulus
illustrating an annulotomy in the annulus in a posterior lateral
quadrant of the annulus which is somewhat shorter than the elongate
incision shown in FIG. 4G such that the annulus is relaxed and such
that there is sufficient room to insert an endoscopic light
delivery system and lens viewing system and also to accommodate
surgical instruments for performing endoscopic discectomy;
[0022] FIG. 4I is a diagrammatic view similar to FIG. 4F
illustrating the elongate incision of FIG. 4H;
[0023] FIG. 4J is a view similar to FIG. 4H illustrating an implant
of the present disclosure installed within the disc space, but
where the implant is somewhat shorter than the implant shown in
FIG. 4, where this implant does not bear on the cortical rim, but
is supported by the endplates of the vertebra bodies;
[0024] FIG. 4K is a view similar to FIG. 4J, where the implant is
somewhat longer than the implant of FIG. 4J and where one end of
the implant partially extends through the elongate incision and
bears at least in part on the cortical rim;
[0025] FIG. 4L is a view similar to FIG. 4E with an implant in
accordance with the present disclosure extending across the
anterior portion of the disc space and bearing on the cortical rim
of the vertebrae bodies;
[0026] FIG. 4M illustrates a typical endoscopic system that may be
used in conjunction with the present disclosure where an endoscopic
camera and light source may be inserted into the disc space through
an elongate incision in the annulus so as to enable the surgeon to
perform discectomy of the disc space with endoscopic viewing;
[0027] FIG. 4N is a view similar to FIG. 4M illustrating the
insertion of endoscopic apparatus and surgical instruments into the
disc space;
[0028] FIG. 4O is a view similar to FIG. 4K illustrating the
placement of the implant across the anterior of the disc space and
illustrating the insertion of endoscopic and surgical instruments
into the disc space;
[0029] FIG. 5 is a posterior perspective view on an enlarged scale
of the implant of the present disclosure, as viewed from above,
having an upper and a lower body member with a space between the
inner faces of these upper and lower body members and with a spacer
of predetermined thickness inserted within the space between the
body members so that when the disc space is retracted, the body
members and the spacer maintain a desired distraction between the
adjacent vertebrae bodies and bear normal spinal biomechanical
loads until solid spinal fusion is achieved;
[0030] FIG. 6 is a posterior perspective view of the implant shown
in FIG. 5, as viewed from below;
[0031] FIG. 7 is an anterior perspective view of the implant shown
in FIG. 6, as viewed from above;
[0032] FIG. 8 is another anterior perspective view of the implant,
as viewed from below;
[0033] FIG. 9 is a posterior elevational view of the implant
illustrating oblique slots in the inner faces of the upper and
lower body members with a spacer inserted between the inner faces
of the upper and lower body members;
[0034] FIG. 10 is a vertical cross sectional view of the implant
taken along line 10-10 of FIG. 9;
[0035] FIG. 11 is anterior view of the implant shown in FIG. 9;
[0036] FIG. 12 is a top plan view of the implant;
[0037] FIG. 13 is a lengthwise vertical cross sectional view taken
along line 13-13 of FIG. 12;
[0038] FIG. 14 is a bottom plan view of the implant;
[0039] FIG. 15 is a right side elevational view of the implant as
shown in FIG. 12;
[0040] FIG. 16 is a left side elevational view of the implant as
shown in FIG. 12;
[0041] FIG. 17 is a bottom perspective exploded view of the
implant;
[0042] FIG. 18 is a top perspective exploded view of the
implant;
[0043] FIG. 19 is an anterior perspective view of a second
embodiment of the implant of the present disclosure illustrating a
tab extending upwardly from the anterior end of the lower body
member with the tab being adapted to fit within a corresponding
recess in the anterior face of the upper member so that upon
distraction of the space between the body members and with a spacer
disposed within the space between the upper and lower body member,
the tab prevents anterior displacement of the spacer from between
the body members;
[0044] FIG. 20 is a bottom perspective view of the implant shown in
FIG. 19;
[0045] FIG. 21 is a top plan view of the implant shown in FIGS. 19
and 20, with a spacer (shown in dotted lines) positioned between
the upper and lower body members;
[0046] FIG. 22 is a vertical section view taken along line 22-22 of
FIG. 21 illustrating a first or anterior detent protuberance
projecting downwardly from the bottom face of the spacer with this
first detent protuberance being received in a corresponding first
enlarged recess in the top face of the lower body so as to aid in
locating the spacer relative to the lower body member and so as to
prevent displacement of the spacer relative to the lower body
member upon retraction of the space between the upper and lower
body members and upon application of compression and in normal
use;
[0047] FIG. 23 is a vertical section view taken along line 23-23 of
FIG. 21 illustrating a second or posterior detent protuberance
projecting downwardly from the bottom face of the spacer with this
second detent protuberance being received in a corresponding second
enlarged recess in the top face of the lower body so as to aid in
locating the spacer relative to the lower body member and so as to
prevent displacement of the spacer relative to the lower body
member upon compression of the space between the upper and lower
body members;
[0048] FIG. 24 is an exploded perspective view of the implant shown
in FIGS. 19-23, as viewed from above;
[0049] FIG. 25 is an exploded perspective view of the implant shown
in FIGS. 19-24, as viewed from below, illustrating a pair of spaced
detent protuberances on the bottom face of the spacer;
[0050] FIG. 26 is an anterior exploded perspective view, as viewed
from above, of the implant illustrating the location of the first
and second protuberance receiving recesses formed in the upper face
of the lower body, as these recesses are positioned relative to the
diagonal slot provided in the lower body for receiving the lower
blade of a parallel distractor used to expand the space between the
upper and lower body members;
[0051] FIG. 27 is a top plan view of the lower implant body member
shown in FIGS. 19-26 in which the spacer is substantially centered
between the stabilizing posts and in which the anterior and
posterior detent protuberances (as shown in dotted lines) are
substantially centered relative to their respective recesses (also
shown in dotted lines);
[0052] FIG. 28 is a posterior side elevational view of the implant
shown in FIG. 27 with the space between the upper and lower body
members distracted and with a spacer interposed between the upper
and lower body members with the lateral ends of the spacer
substantially centered between the stabilizing posts;
[0053] FIG. 29 is a top plan view of the lower implant body with
the spacer being offset within the space between the stabilizing
posts toward and bearing against the left-hand post such that both
the left-hand post and the detent protuberances are received in
their respective recess so as to positively prevent lateral
movement of the spacer, and such that the protuberances cooperating
with their respective recesses positively prevent movement of the
spacer relative to the implant bodies;
[0054] FIG. 30 is a posterior side elevational view of the implant
shown in FIG. 29 with the spacer located in the position shown in
FIG. 29 with the space between the implant bodies members
distracted a distance greater than the thickness of the spacer;
[0055] FIG. 31 is an exploded perspective view of the implant
having an alternative spacer having a "wing" or extension extending
laterally from each posterior side of the spacer for cooperating
with the stabilizing posts thereby to prevent anterior movement of
the spacer beyond a predetermined location for the spacer between
the body members;
[0056] FIG. 32 is a posterior exploded perspective view of the
implant and spacer illustrated in FIG. 31;
[0057] FIG. 33 is a top plan view of the implant shown in FIGS. 31
and 32 with the alternative spacer positioned between the upper and
lower body members with the wings or extensions bearing against
their respective posts so as to prevent anterior movement of the
spacer beyond the position of the spacer shown;
[0058] FIG. 34 is a posterior side elevational view of the implant
shown in FIG. 33;
[0059] FIG. 35 is a top plan view of the lower body member having
the alternate spacer positioned thereon with the left lateral side
of the spacer bearing against the left post and with the wings or
extensions bearing against the respective posterior faces of their
respective posts so as to prevent anterior movement of the spacer
relative to the lower body member beyond the position shown;
[0060] FIG. 36 is a bottom perspective exploded view of still
another embodiment the implant similar to that shown in FIGS. 31-35
in which the spacer has a pair of "wings" or tabs on one end and a
single "wing" or tab on the other end with the space between the
pair of tabs being spaced as to receive a post such that with the
spacer inserted between the implant bodies and rotated such that
the spacer is substantially parallel to the implant bodies where
the posterior tabs prevent anterior movement of the spacer relative
to the posts and the anterior tab prevents posterior movement of
the spacer;
[0061] FIG. 37 is a top perspective exploded view of the implant
and spacer shown in FIG. 36;
[0062] FIG. 38 is a top plan view of the implant and the spacer
showing the spacer prior to being inserted between the implant
bodies oriented at an angle with respect to the implant body so as
to be inserted between the implant bodies;
[0063] FIG. 39 is a view similar to FIG. 38 with the spacer
partially inserted between the upper and lower implant bodies with
a stabilizing post received between the pair of spaced wings or
tabs;
[0064] FIG. 40 is a view similar to FIG. 39 showing the spacer
partially rotated toward its installed position in which the spacer
is substantially parallel to the body members;
[0065] FIG. 41 is a view similar to FIG. 40 showing the spacer in
its fully installed position;
[0066] FIG. 42 is a perspective view of another embodiment of an
expandable or variable height implant of the present disclosure
(shown without its spacer positioned between the inner faces of its
upper and lower body members) having angled (tapered) upper and
lower surfaces for treating or correcting certain lordotic
conditions;
[0067] FIG. 43 is a top plan view of the lower body of the implant
shown in FIG. 42;
[0068] FIG. 44 is a posterior elevational view of the implant of
FIGS. 42 and 43;
[0069] FIG. 45 is a bottom plan view of the implant of FIGS.
42-44;
[0070] FIG. 46 is a side elevational view of the implant of FIGS.
42-45 illustrating the angled upper and lower faces that constitute
a lordosis angle for treating or correcting certain lordotic
conditions;
[0071] FIG. 47 is a side elevational view of the implant of FIGS.
42-46 on an enlarged scale illustrating a lordosis angle of both
the upper and lower body members;
[0072] FIG. 48 is a perspective view of still another embodiment of
the implant of this disclosure where the implant is a one piece
non-expandable implant, but rather is of a fixed height, where such
implant has angled or tapered upper and lower surfaces and may be
readily utilized in accordance with the methods of this
disclosure;
[0073] FIG. 49 is a top plan view of the implant of FIG. 48;
[0074] FIG. 50 is a front elevational view of the implant of FIGS.
48, 49;
[0075] FIG. 51 is a bottom plan view of the implant of FIGS.
48-50;
[0076] FIG. 52 is a side elevational view of the implant of FIGS.
48-51 illustrating the lordosis angles of the upper and lower
surfaces of the implant;
[0077] FIG. 53 is a side elevational view of the implant of FIGS.
48-52 on an enlarged scale illustrating the lordosis angles of the
upper and lower surfaces of the implant;
[0078] FIG. 54 is a perspective view of still another
non-expandable embodiment of the implant of this disclosure where
such implant is fenestrated having openings therein and where such
implant may be readily utilized in accordance with the methods of
this disclosure;
[0079] FIG. 55 is a top plan view of the implant of FIG. 54;
[0080] FIG. 56 is a front elevational view of the implant of FIGS.
54, 55;
[0081] FIG. 57 is a bottom plan view of the implant of FIGS.
54-57;
[0082] FIG. 58 is a side elevational view of the implant of FIGS.
54-57 illustrated the angles upper and lower surfaces of the
implant;
[0083] FIG. 59 is a side elevational view of the implant of FIGS.
54-58 on an enlarged scale illustrating a lordosis angle for the
upper and lower surfaces of the implant;
[0084] FIG. 60 is posterior top perspective view of still another
embodiment of the implant of the present disclosure where the upper
and lower body members have a slot in their respective inner faces
and where the spacer may have a corresponding slot in register with
either the slot in the upper or the lower body member where the
posterior ends of these slots may be somewhat wider than the
remainder of the slot so as to aid in guiding the operating tips of
a distractor or other instrument into the slots;
[0085] FIG. 61 is an exploded perspective view of the implant shown
in FIG. 60, as viewed from above;
[0086] FIG. 62 is a posterior bottom perspective view of the
implant shown in FIGS. 60 and 61;
[0087] FIG. 63 is an exploded perspective view of the implant shown
in FIGS. 60-62 illustrating the slot in the upper face of the
spacer;
[0088] FIG. 64 is a top perspective view of another embodiment of
the implant of the present disclosure similar to the implant shown
in FIGS. 60-63 with the spacer omitted for illustration purposes,
but where the bottom body member is split so that it may be
assembled around the flanged posts protruding from the bottom of
the upper body member and then adhesively joined so posts are
captured in the corresponding holes in the bottom body member, with
the halves of the bottom body member each having an alignment pin
adapted to be received in a corresponding hole in the opposite
bottom body member half;
[0089] FIG. 65 is a bottom perspective exploded view of the implant
shown in FIG. 64;
[0090] FIG. 66 is an exploded perspective view of a distractor
instrument used to distract the implant of this disclosure in situ
having operating tips in accordance with the instant disclosure
with the distal end of one (or both) of the operating tips having a
cleat or hook for engagement with the anterior surface of one of
the implant body members when the operating tips are fully inserted
into and through the slots in the upper and lower body member such
that the cleat engages the implant and allows the implant to be
maneuvered within the disc space and allows the implant and the
adjacent vertebrae to be distracted without becoming disengaged
from the distractor;
[0091] FIG. 67 is a right perspective view of the distractor of
FIG. 66 having the operating tips installed;
[0092] FIG. 68 is a left elevation view of the distractor of FIG.
66 illustrating a gap between the inner surfaces of the operating
tips through which a spacer of the implant of the present
disclosure may be inserted into the disc space and inserted between
the inner surfaces of the distracted upper and lower body members
of the implant;
[0093] FIG. 69 is a top plan view of the distractor and operating
tips of FIG. 68;
[0094] FIG. 70 is a front elevational view of the distractor and
operating tips of FIG. 68;
[0095] FIG. 71 is a view similar to FIG. 4 showing the distractor
of FIGS. 66-70 with its operating tips and operating arms of the
distractor inserted through the incision in the posterior lateral
quadrant of the annulus with a paddle blade distractor inserted
into the gap between the inner faces of the operating arms/tips of
the distractor so that upon rotation of the paddle blade distractor
about its longitudinal axis by the surgeon the implant of this
disclosure and the adjacent vertebrae are distracted a first
increment corresponding to the width of the paddle blade distractor
so as to insure that the upper and lower implant body members are
distracted a first known increment and so as to insure that the
operating tips of the distractor are generally parallel;
[0096] FIG. 72 is a perspective view of a paddle blade distractor
having a T-handle and a paddle blade having an operating tip or
distal end of a predetermined width;
[0097] FIG. 73 is a view somewhat similar to FIG. 4 with the
annulus omitted for purposes of clarity illustrating the
distraction of two adjacent vertebrae (e.g., L3 and L4) with an
implant of the present disclosure inserted in the manner shown in
FIG. 4 and with the operating tips of a distractor, such as shown
in FIGS. 66-70, positioned between the inner faces of the upper and
lower body members of the implant so as to distract the implant and
the vertebrae upon actuation of the distractor;
[0098] FIG. 74 is a view similar to FIG. 73 illustrating the
insertion of a paddle blade distractor, such as shown in FIGS. 71
and 72, inserted between the inner faces of the operating tips of
the distractor so as to distract the implant at least the width of
the operating tip of the paddle blade distractor and to return the
operating tips to a substantially parallel relation to one another
in the event that the thin operating tips have deflected somewhat
(from the position that they are shown in FIG. 74) upon operation
of the parallel distractor; and
[0099] FIG. 75 is a view similar to FIG. 74 with the paddle blade
distractor rotated about 90.degree. from its position shown in FIG.
74, and with portions of the operating tips of the parallel
distractor, the operating blade of the paddle blade distractor, and
the upper and lower body members of the implant being shown in
cross section illustrating how the distal end of the paddle blade
distractor distracts the implant (and thus also distracts the disc
space) and insures that the operating tips of the parallel
distractor are returned to a substantially parallel condition upon
the paddle blade distractor being rotated approximately 900.
[0100] Corresponding reference characters indicate corresponding
parts throughout the several views of the drawings.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0101] Referring now to the drawings and particularly to FIGS.
1-4C, a first embodiment of a lumbar disc implant device of the
present disclosure is generally indicated at 1 (see FIG. 2), and is
shown in its intended environment installed within the disc space
DS between two adjacent human vertebrae to be fused together.
Oftentimes the intervertebral disc 3 between two adjacent vertebrae
(e.g., between lumbar vertebrae L3 and L4, or between lumbar
vertebrae L4 and L5) may become degenerated and mechanically
incompetent with subsequent loss of height between the adjacent
vertebrae with resultant pain and loss of motion. It has become
common practice to surgically reconstruct the degenerated disc 3
between the opposing surfaces of the vertebrae bodies and to insert
a structural implant within the disc space between the vertebrae so
as to space the vertebrae apart a desired distance thus restoring
disc space height, and to bear normal biomechanical loads in the
spine until a solid spinal fusion occurs. As is conventional, bone
graft material (not shown) is introduced into the disc space for
fusing the adjacent vertebrae together as the bone graft material
grows. Also, such prior disc structural implants are stabilized by
known vertebrae fixation devices, such as pedicle screw and rod
fixation, which are widely known, but are not shown in the
drawings.
[0102] As shown in FIG. 4A, an approach is made generally in accord
with known transforaminal interbody fusion (TLIF) procedures.
Specifically, with the patient in a prone position, fluoroscopy
localization is used to place an incision at the desired level.
Either an open approach or an approach using a tubular retractor 7,
as shown in FIG. 4A, may be used, as is well known in the art. Such
a posterolateral TLIF approach is familiar to spine surgeons and
does not risk the great vessels and abdominal viscera associated
with ALIF (Anterior Lumbar Interbody Fusion) procedures nor does
such an approach require an anterior access surgeon. Further, the
TLIF approach does not risk injury to the lumbar plexus.
[0103] Further as shown in FIG. 4B, transforaminal access to the
disc space DS between the vertebrae is achieved by resection of the
inferior facet IF of L3, a portion of the pars interarticularis,
and a portion of the superior facet SF of L4. Distraction (i.e.,
the forcing apart or separation of the vertebrae surfaces) to
improve the working corridor may be achieved by using a laminar
spreader or pedicle screws, both of which are well-known in the art
and which are therefore not shown. Discectomy, a surgical procedure
for removal of the disc material from within the annulus 9, is
performed through an incision or annulotomy 11, preferably, but not
necessarily, a posterior oblique annulotomy, within the operative
field (shown in FIGS. 1 and 4C) made in the wall 13 of the annulus
9. Endplate preparation follows using standard procedures and
instruments including cupped curettes, ring curettes, box curettes,
broaches, box chisels, rasps, and pituitary rongers. All of the
disc material between the adjacent vertebrae bodies is removed
while the walls 13 of annulus 9 are preserved. The cartilaginous
endplates of the vertebrae are removed down to bleeding bone, but
care is taken to preserve the cortical endplate, especially
anteriorly.
[0104] More specifically and as shown in FIG. 4C, incision
(annulotomy) 11 in annulus 9 permits perforations or openings (also
referred to as annulotomies) 15a, 15b, as best shown in FIG. 4, to
be made in opposite lateral sides of the anterior annulus such that
these openings are generally laterally symmetrical. Those skilled
in the art will recognize that a surgeon having access to the
interior of the disc space DS via incision 11 will, with proper
vision magnification (e.g., a loupe or with endoscopic assistance),
be able to make a first opening 15a distal from and opposite
incision 11. Then, the surgeon can make the second opening 15b
generally across the annulus from the first opening 15a on the
opposite anterolateral side of the disc or the annulus (i.e., in
the ipsilateral quadrant of the disc relative to incision 11).
These annulotomies (including incision 11 and openings 15a, 15b)
also serve as anterior and posterior releases to facilitate disc
space DS distraction.
[0105] More specifically, these anterior annulotomies 15a, 15b may
be further relaxed using a variety of techniques including the use
of so-called "trials" and distractor instruments, as are well known
to those skilled in the art. It is common for surgeons to utilize
metal trial implants (not shown) for gaging the size of the actual
implant to be used where the trial is at least in part shaped like
the implant 1 to be used. Such trials are typically provided in a
range of widths, lengths and heights. With the disc space DS at
least partially distracted, the surgeon will install a first trial,
typically of a smaller size, length, width or height than the
implant 1 that will be finally installed, through the anterior
annulotomies. These trials are used to aid in distracting the
vertebrae and to hold the vertebrae in this desired distracted
position. After the ligaments and the annulus at least partially
relax, further distraction of the disc space may be accomplished by
actuation of a parallel distractor applied to the anterior
annulotomies bilaterally. Another trial, typically somewhat larger
than the first trial, may be inserted if further relaxation of the
anterior annulotomies is required. It will be understood that the
trials can be used to judge the width and height of the size of the
actual implant 1 to be employed. Then, with the disc space DS
prepared, the implant 1 of the proper height, length, and width
will be installed, preferably in the manner discussed below.
[0106] FIG. 4D is a view similar to FIG. 4, but where the implant 1
has been removed from the disc space DS so as to better show the
incision 11, the first opening 15a, and the second opening 15b, as
they may be formed in annulus 9.
[0107] FIG. 4E is a view similar to FIG. 4D, but where one elongate
incision, as indicated at A1, is made in annulus 9, where the
posterior portion of the elongate incision incorporates incision 11
and where the anterior portion of the elongate incision
incorporates the second opening 15b. Still further, the first
opening 15a is incorporated in an elongate incision A2. These
elongate incisions A1 and A2 help relax the annulus. As will be
particularly described below in regard to FIGS. 4M-4O, the elongate
incision A1 allows for the insertion of endoscopic and surgical
instruments so that the surgeon may perform the discectomy of the
disc space DS under endoscopic viewing.
[0108] FIG. 4F is a diagrammatic axial illustration of the
vertebrae and the annulus 9 showing the Sagittal Midline Axis, the
Coronal Midline Axis of the Disc, and other prominent anatomical
features of the vertebrae and the approximate location of incision
11 and openings 15a and 15b illustrated in FIGS. 4 and 4D.
Alternatively, as shown in FIGS. 4E and 4G, the incision 11 and the
second opening 15b may be formed by a single elongate annulotomy A1
where the incision 11 is a posterior portion of the elongate
annulotomy A1 and where the second opening 15b is the anterior
portion of the elongate annulotomy A1, and where the first opening
15a may be the anterior portion of another elongate annulotomy A2
on the opposite side of the annulus 9. These elongate annulotomies
A1 and A2 relax the annulus and release the disc space to better
facilitate the distraction of the adjacent vertebrae. It will be
appreciated that the elongate annulotomies A1 and/or A2 serve to
maximize the release of the disc space DS and the relaxation of
annulus 9 to facilitate distraction. Still further, the elongate
annulotomies A1 and/or A2 facilitate discectomy and/or end plate
preparation by allowing the surgeon to have a larger field of view
of the disc space, either with increased magnification (e.g., a
loupe) or with endoscopic assistance (as shown in FIGS. 4M-4O). It
will be appreciated that the elongate annulotomies A1 and A3 afford
increased room for the insertion of surgical instruments SI (either
manual or powered instruments), as shown in FIG. 4N, for performing
surgical procedures within the disc space DS, such as discectomy
and end plate preparation, and for enhancing the surgeon's field of
view of the disc space. Examples of manual surgical instruments may
include, but may not be limited to, the above described cupped
curettes, ring curettes, broaches, box chisels, rasps, and
pituitary rongers. Further, the elongate annulotomy A1 allows an
endoscopic light delivery system to illuminate the disc space and
an endoscopic lens system to transmit the image to be viewed by the
surgeon. Endoscopic apparatus, such as indicated at 801 in FIGS.
4M-4O, which is described in detail below, may be used. An
advantage to being able to perform the discectomy and/or endplate
preparation under endoscopic viewing is that power tools, such as
the Midas Rex Spine Shaver Nucleus Removal Set, commercially
available from Medtronic, Inc. of Minneapolis, Minn., may be used
because the surgeon now has the ability to see and to better
control the use of such instruments.
[0109] As shown in FIGS. 4, 4D, and 4F, the incision 11 is formed
in the posterior lateral quadrant of the disc space DS in the
position generally as shown in FIG. 4F. Further, the first opening
15a is formed in the annulus 9 in the generally opposite anterior
lateral quadrant of the disc space and the second opening 15b is
formed in the contralateral anterior quadrant (i.e., on the same
side as incision as 11 or in the ipsilateral anterior lateral
quadrant relative to incision 11). It will be understood that if it
is desired that the approach be from the contralateral side, the
openings would be reversed from their position as shown in FIG. 4.
Also, the direction of the slots 31a, 31b in the implant will be
reversed.
[0110] More specifically, it will be understood by those of
ordinary skill in the art that the incision 11 and the openings
15a, 15b may be the mirror image of their locations shown in FIG.
4F, and that the elongate openings or incisions A1 and A2 may be
the mirror image of their locations shown in FIG. 4G. It will also
be understood by one skilled in the art that the location and the
length of the incisions or openings 11, 15a, 15b, A1 and A2, as
shown in FIGS. 4F and 4G, are only the approximate locations of
these incisions or openings in the annulus 9 and that a surgeon
using the implants and methods of this disclosure may vary, at the
surgeon's discretion, alter the locations and lengths of these
incisions and openings to fit the anatomical features of the
particular patient undergoing the operation. It will also be
understood that even if the elongate incisions A1 and A2 are not
employed, the incision 11 and the openings 15a, 15b may be
considerably longer than is shown in FIGS. 4D and 4F.
[0111] Referring now to FIGS. 4H-K and FIGS. N-O, it will be noted
in FIG. 4H that the incision A3 in the posterior lateral quadrant
is considerably longer than incision 11 and that includes incision
11. It has been found that such a longer incision relaxes the
annulus thereby facilitating discectomy and distraction of the disc
space DS. This longer incision A3 is diagrammatically illustrated
in FIG. 4I.
[0112] As shown in FIG. 4J, after discectomy of the disc space DS,
an implant, as generally indicated in its entirety at I made in
accordance with any of the embodiments disclosed herein or any
other conventional implant may be inserted into the anterior region
of the disc space, where the implant is supported on the end plates
of the vertebra. This implant I maintains distraction of the disc
space while bone growth or bone graft material (not shown) is
packed into the remaining area of the disc space fuses the
vertebra.
[0113] As shown in FIG. 4K, an implant I' may be somewhat longer
than implant I shown in FIG. 4J where one end of the implant I' may
partially extend through the anterior portion of incision A3 so
that this one end of the implant is supported on the cortical rim
CR. Again, implant I' may be any of the embodiments of the implants
disclosed herein or any other conventional implants.
[0114] FIG. 4L is similar to FIGS. 4E and 4G having elongate
incisions or annulotomies A1 and A2 in annulus 9 with an implant
I'' installed within disc space DS extending across the anterior
region of the vertebrae bodies VB where the ends of the implant I''
are supported on the cortical rims CR of the vertebrae bodies.
Implant I'' may be any of the embodiments of the implants disclosed
herein or any other conventional implants.
[0115] FIG. 4M illustrates endoscopic surgical apparatus 801 that
may be employed to aid the surgeon in performing the discectomy of
the disc space DS thus giving the surgeon the ability to view the
disc space while the discectomy is being performed. Heretofore, the
surgeon performed the discectomy "blind" and was not able to see
into the disc space. In accordance with the present disclosure
there is an advantage of performing the discectomy under endoscopic
viewing because the surgeon can typically perform the discectomy
faster and can visually insure that the discectomy is properly
performed such that little or no debris remains in the disc space
after discectomy, where such debris may interfere with the growth
of the bone growth material packed into the disc space and with the
fusing of the vertebra.
[0116] As is conventional, such endoscopic surgical apparatus 801
includes a housing 803 and a fiber optic light transmitting tube
805 that transmits light from 803 to a lens in the distal end of
the tube to illuminate the disc space. Additionally, the end of the
tube 805 includes a wide angle lens 807 which transmits an image of
the disc space via tube 805 to a wireless transmitter in housing
803 to a wireless receiver base station 809, which in turn displays
the image on a monitor 811 to be viewed by the surgeon performing
the discectomy. It will be appreciated that, as is conventional,
the surgeon may grip housing 803 to maneuver the distal end of the
light tube 805 in the disc space so as to allow the surgeon to view
different areas of the disc space. It is also appreciated that in
lieu of wireless coupling of fiber optic endoscope to monitor
cables maybe used.
[0117] As shown in FIG. 4N, the elongate incision A3 provides ample
room for the insertion of the endoscopic tube 805 and the lens 807
so that the surgeon may operate surgical instruments SI (either
manual or powered) to perform the discectomy under endoscopic
viewing.
[0118] FIG. 4O shows that there is ample room within the disc space
DS with the elongate incision A3. It will be appreciated that
initial endplate preparation may be carried out prior to
distraction. However, after the disc space has been distracted and
after the implant is in place between the adjacent vertebrae bodies
VB, a surgeon may prefer to complete endplate preparation under
endoscopic viewing so as to result in better preparation.
[0119] Implants 1 are available in a series of various
predetermined lengths, widths and heights to best fit particular
patients. For example, the length of a typical implant 1 may be
about 50 mm and about 8.5 mm tall. Calipers or trials (not shown)
are used to measure and size the anterior disc space and to
determine the length of the implant 1 to be used. Intraoperative
fluoroscopy will aid in these measurements.
[0120] With the desired final height, width and length of the
implant 1 determined, and with the implant in its collapsed or
retracted position (for example, with spacer 35 removed from
between the body members 17 and 19 and with the inner faces of the
body members in contact with one another), the implant is inserted
into the disc space DS via incision 11 at an oblique angle using
the implant applicator (not shown) or other suitable instrument.
The implant applicator grasps the implant firmly allowing
controlled insertion and positioning of the distal end of the
implant thru the contralateral anterior annulotomy 15a. The
insertion of the implant is also disclosed in conjunction with the
distractor 601, as described hereinafter. Once the proximal end of
the implant is within the disc space DS, the applicator is removed.
The parallel distractor may be used to maneuver implant into final
position with both ends protruding through anterior annulotomies
15a, 15b, generally as shown in FIG. 4.
[0121] In this manner, the implant bears against and is supported
at least in part by the cortical rim CR of both the upper and lower
vertebrae. Fluoroscopic confirmation (as hereinafter described) of
optimal positioning utilizing radiographic markers, as indicated at
43 in FIGS. 5 and 6, embedded in the implant is carried out. After
the implant 1 has been so oriented and positioned within the disc
space DS, the blades of a parallel distractor (not shown in FIG. 4,
but which distractor may be similar to the distractor 601
hereinafter described) are inserted into the disc space via
incision 11 in the annulus 9. The disc space and the implant are
then further distracted and a spacer, as indicated at 35 and as
shown below, is installed within the implant in a manner as will
appear. Upon removal of the parallel distractor and upon applying
compression to the construct, the implant bodies 17, 19 and the
spacer 35 will maintain the implant 1 in its desired height.
[0122] Referring now to FIGS. 5-17, the implant 1 of the present
disclosure will now be described in detail. As shown in FIG. 5,
implant 1 has a pair of separate body members 17 and 19, with body
member 17 being referred to as a lower body member and with body
member 19 being referred to as an upper body member with a space 21
therebetween. It will be appreciated that with the inner faces of
the body members touching one another the space 21 is minimized and
the overall height of the implant is minimized. With implant 1 in
this position, it has a low profile that facilitates insertion and
final positioning within disc space DS. Further, with the body
members 17 and 19 spaced apart a maximum distance, the implant is
in its fully distracted position. The height of implant 1 thus may
be expanded in situ a desired amount to enable distraction of the
degenerated disc 3 to normal anatomic height with appropriate
tensioning of the annulus 9 and stabilizing ligaments.
[0123] As best shown in FIG. 13, the upper member 19 has a pair of
spaced stabilizing posts 23a, 23b extending down into space 21.
These stabilizing posts 23a, 23b are each received in a respective
bore 25a, 25b in the lower member 17. As indicated at 27, each bore
25a, 25b has an inwardly extending flange of somewhat smaller
diameter than the remainder of the bore, with the diameter of the
flange 27 being only somewhat larger than the diameter of the
stabilizing posts 23a, 23b. Further, at the distal end of each of
the stabilizing posts, an enlarged head 29 is provided with the
head being somewhat larger than the diameter of the post and being
somewhat larger than the bore in flange 27. In this manner, with
the posts received in their respective bores, the heads 29 on the
end of each post cooperates with flange 27 so as to prevent the
body members 19 and 21 from becoming distracted (moved apart) more
than a predetermined distance. As best shown in FIG. 17, each of
the stabilizing posts 23a, 23b may have an optional longitudinal
slot 30 which enables the post to be somewhat resiliently
compressed so that the flanges 29 on the ends of the posts may be
inserted through the bores thus allowing the posts to be received
in their respective bores 25a, 25b. Once the posts have been
inserted in the bores, the posts will spring back to resume their
shape and size prior to being compressed. It will be further
understood that the bodies of posts 23a, 23b preferably have a
sliding close fit within the bores of their respective flanges 27
such that the posts stabilize the upper and lower body members
relative to one another so as to resist the body members from
twisting, shearing, or tipping relative to one another in all
directions. These stabilizing posts help maintain the body members
17 and 19 oriented in a desired parallel relation to one another as
the implant 1 is inserted within the disc space DS and distracted,
in the manner as will be hereinafter described. Further, the
provision of flanges 27 and 29 provide a tactile feel that prevents
over distraction of the body members 17 and 19. While the
above-described stabilizing posts 23a, 23b have been described as
having slots 30 therein, it will be understood that the slots may
be omitted and that the posts may be solid members.
[0124] As perhaps best shown in FIG. 18, each of the body members
17 and 19 has a respective oblique or angled slot 31a, 31b formed
in its inner face. When the body members are assembled as shown in
FIG. 13 and with the implant 1 installed as described above with
the implant bearing on the cortical rims CR of the vertebrae
bodies, the slots 31a, 31b are oriented so as to be generally in
alignment with incision 11 in annulus 9 so to allow the blades of a
distractor instrument (which may be similar to distractor 601
hereinafter described) to be inserted in line into these slots.
With the operating blades of the distractor received in slots 31a,
31b, the distractor may then be operated so as to distract the body
members 17 and 19 and so as to simultaneously distract the
vertebrae bodies on opposite sides of the disc space DS a desired
amount. The parallel distractor is used to expand the space 21
between the body members 17 and 19 using preoperative imagining and
intraoperative tactile feedback of annular and ligamentous
tensioning. Of course, when spacer 35 of the proper predetermined
thickness is inserted in space 21, the desired amount of
distraction is maintained. It will be appreciated that the angled
slots 31a, 31b are substantially centered with respect to implant 1
so as to balance the distraction loading and so as to minimize
binding of the stabilizing posts 23a, 23b within the openings of
flanges 27 upon distraction and retraction of the body members
relative to one another.
[0125] A spacer 35 of predetermined thickness is insertable within
the space 21 between body members 17 and 19 once the disc space DS
and the body members 17 and 19 of implant 1 have been distracted
the desired amount. In accordance with this disclosure, a series of
spacers 35 of predetermined thicknesses may be provided so that,
depending on the amount of distraction needed, and depending on the
disc space and the anatomical characteristics of the patient, a
spacer is provided for the amount of distraction required. For
example, spacers 35 may be provided in predetermined thicknesses
of, for example, 1 mm, 2 mm, 3 mm, etc. The shape and size of
spacers 35 distribute the anatomical spinal loads over a relatively
wide surface area of the upper and lower body members 17, 19. The
geometry of slots 31a, 31b facilitates easy withdrawal of the
distractor instrument after shim or spacer 35 has been properly
positioned between the implant members 17 and 19. Of course, it
will be recognized that the distractor instrument may be used for
final positioning and placement of implant 1 within the disc
space.
[0126] As shown in FIG. 4, the length of implant 1 is sufficient so
as to span the disc space DS anteriorly, and to bear on the
cortical rims CR of the vertebrae bodies. The upper face 37 of
upper body 19 and the lower face 39 of lower body 17 are preferably
of a convex shape so as to generally conform anatomically to the
disc space contacting the vertebrae endplates. This anatomic fit of
the implant relative to the adjacent vertebrae in addition to the
load sharing with the cortical rims of the vertebral bodies will
maximize the load bearing capability of the implant. The outer
faces 37 and 39 of body members 19 and 17 may be appropriately
textured so as to prevent migration of the implant relative to the
vertebrae. Still further, the outer anterior ends of the lower and
upper body members are radiused, as indicated at 41, so as to
generally conform to annulus 9 when the implant is positioned
bilaterally within the disc space DS with the outer ends of the
implant in bearing engagement with the hard cortical rims CR of the
upper and lower vertebrae bodies. It will be noted that, as shown
in FIG. 4, the ends of implant 1 may protrude somewhat through the
annulotomies or openings 15a, 15b in the annulus 9. However, it
will be understood that the anterior ends 41 of the lower and upper
body members may be shaped to generally conform to the shape of the
disc space DS so that they do not substantially project out beyond
the outer surfaces of the vertebrae bodies. Of course, if the lower
and upper body members are so shaped to better conform to the
vertebrae bodies and to reduce the protrusion of the ends of the
body members out beyond the disc 3, the ends of spacer 35 would be
similarly shaped.
[0127] After the implant has been inserted in the disc space DS and
oriented and positioned as above described with the ends of the
implant supported at least in part by the cortical rims CR of the
upper and lower vertebrae bodies and after the implant has been
distracted as described and the desired thickness spacer 35 has
been inserted between the lower and upper bodies 17 and 19, bone
graft material may be packed between the implant and the posterior
annulus filling the disc space. Of course, depending on the height
of the cortical rim and the depth of the end plate after
preparation for receiving bone graft material, the implant may also
be supported at least in part by the end plates of the adjacent
vertebrae bodies. It will also be understood that vertebrae
fixation will be used in conjunction with implant 1. The fixation
system used in conjunction with implant 1 is conventional and no
particular system is preferred. It will be understood that as the
bone graft material grows within and substantially fills the disc
space DS, the vertebrae will be fused by this bone growth.
[0128] It will be understood that the lower and upper bodies 17 and
19 of implant 1 and spacer 35 may be made of any suitable material
such as surgical stainless steel, titanium, polyetheretherketone
(PEEK), or carbon fiber reinforced PEEK, other surgical grade
polymer or other material. Of course, the implant 1 and the spacers
are delivered to the operating room in a sterile condition, and are
available in a variety of lengths and profiles to as optimize
patient fit. It may be preferable that implant 1 be made of PEEK
because the modulus of elasticity of PEEK is similar to the modulus
of elasticity of bone. However, PEEK is substantially radiolucent
and thus is not readily viewable in radiographs. If PEEK is used
for the implant, it is preferable that radio opaque markers, as
indicated at 43 (as shown in FIGS. 5 and 6), be inserted within the
implant so that the position and orientation of the implant may be
fluoroscopically verified once the implant has been inserted in the
disc space DS. Preferably, markers 43 are made of tantalum or other
suitable metal so as to show more clearly on radiographic
images.
[0129] With implant 1 properly positioned between the vertebrae,
with the implant properly distracted, with spacer 35 of the proper
thickness inserted between body members 17 and 19, and with the
afore-mentioned bone graft material packed between the implant and
the posterior annulus, conventional posterior spinal fixation
appliances (not shown), such as pedicle screws, are applied.
Compression is applied to the entire construct so as to restore or
maintain sagittal alignment, so as to fixate the structural implant
1 within the disc space DS between adjacent vertebrae, and so as to
provide the optimal environment for bone fusion of the
vertebrae.
[0130] Referring now to FIGS. 19-41, a second embodiment of the
implant of this disclosure is indicated in its entirety by
reference character 101. The "primed" reference characters shown in
FIGS. 19-30 ranging between 1 and 43 indicate parts having
substantially the same construction and function as the parts
identified by these reference characters 1-43 in FIGS. 1-18.
However, some of these components have been modified to carry out a
somewhat different function, as will be described.
[0131] As shown in FIG. 19, lower body member 17' has a tab 103
extending upwardly from the inner surface of one of the body
members, for example, the lower body member along the anterior end
thereof. This tab 103 extends up from the upper surface of the
lower body member a distance sufficient so as to be at least
partially slidingly received in a corresponding groove 105 formed
in the anterior wall 107 of the other body member, for example,
upper body member 19' when a spacer 35' is received within space
21' between the upper and lower body members and when the upper and
lower body members are at least partially retracted with spacer 35'
disposed therebetween. In this manner, tab 103 prevents movement of
the spacer beyond the anterior end of the body members and thus
self-locates the spacer in anterior/posterior direction. The tab
further prevents anterior migration of the spacer 35' beyond the
anterior edge of lower body member 17' during normal use of the
implant by the patient. While tab 103 is shown to be an elongate
single tab extending along the anterior edge of the spacer 35', it
will be understood that the tab may actually be two or more spaced
tabs extending upwardly from the spacer.
[0132] Referring now to FIGS. 21-30, the bottom face of spacer 35'
is shown to have a pair of downwardly projecting male
protuberances, as indicated at 109a, 109b. Each of these
protuberances has a generally part-spherical convex outer surface
for purposes as will be described. Further, the upper surface of
lower body member 17' has a corresponding pair of female recesses,
as indicated at 111a, 111b, positioned to receive a respective
protuberance. Each of these female recesses has a generally
part-spherical concave surface that is engaged by its respective
male protuberance. As shown best in FIGS. 22-28, each recess 111a,
111b is larger in diameter than its respective protuberances 109a,
109b for purposes as will appear. As shown in FIG. 24, recesses
111a, 111b are spaced on opposite sides of slot 31b' in areas of
the upper surface of lower body member 17' large enough to
accommodate the recesses. As further shown in FIG. 21,
protuberances 109a, 109b are preferably spaced on opposite sides of
a first centerline CL1 (as shown in FIG. 21) of spacer 35' an
equidistant amount. The respective recesses 111a, 111b are also
preferably equidistantly spaced on opposite side of a second
centerline CL2 (as shown in FIG. 27) diametrically extending
through bores 25a', 25b' in lower body member 17'. However, those
skilled in the art will recognize that the location of the
protuberances and the recesses may be at any desired location. It
will be further understood that while two protuberances and two
recesses are shown, that other numbers of and shapes of the
protuberances and recesses may be utilized.
[0133] It will be appreciated by those skilled in the art that
instead of protuberances 109a, 109b being provided on the bottom
face of spacer 35', they may instead (or may in addition) be
provided on the upper face of the spacer and the recesses 111a,
111b may be provided on the lower face of the upper body member
19'. Further, it will be understood that the recesses may be
provided on the spacer and the protuberances may be provided on a
cooperating inner face of an adjacent body member.
[0134] It will also be appreciated that because recesses 111a, 111b
are of larger diameter than their respective protuberance 109a,
109b, and because the generally part-spherical surfaces of the
convex male protuberances engage the generally part-spherical
female concave surfaces of their respective recesses, the mating
convex surface of the protuberance acts like a cam follower and
concave surfaces of the recesses act as a cam so that upon the
application of compressive loads to the implant 101, the
cooperating and complimentary protuberances and recesses will guide
or force the protuberances to move downwardly toward the bottom of
the concave recesses so as to self-position and/or to self-center
the spacer relative to the body members. While the shape of the
protuberances are recesses have been described as being preferably
part-spherical, it will be understood that, in accordance with this
disclosure, that other rounded shapes may be employed.
[0135] In use, as the distractor instrument (not shown) is
withdrawn from slots 31a', 31b', as the disc space DS is retracted,
and as compression is applied to the spinal column, this
compression will tend to effect the above-described camming action
that will self-center (or self-align) the spacer 35' in proper
position within the space 21' between the upper and lower body
members 19' and 17'. Further, with such compression loads applied
to implant 101, protuberances 109a, 109b will interfere with (bear
against) the sides of the recesses 111a, 111b thereby to securely
hold or retain spacer 35' in its desired position within space 21'.
Further, the complimentary protuberances and recesses, when under
compression loading, cooperate with one another so as to resist
migration of the spacer relative to the body members during normal
use by the patient. It will also be appreciated that the height of
the protuberances and the depth of the recesses are such that with
the protuberances received within their respective recesses, the
protuberances may carry at least some of the compression load
applied to spacer 35' by the upper and lower body members 17', 19'
of implant 101. Still further, with the protuberances 109a, 109b
positioned in the bottom of their respective recesses 111a, 111b,
respectively, the protuberances and the recesses prevent or resist
movement (migration) and pull-out of the spacer relative to the
body members 17', 19' in all directions. Also, the posts 23a, 23b
will prevent lateral displacement of the spacer within the implant
101.
[0136] It will be further noted in FIGS. 27 and 28 that with the
spacer in its desired position, the protuberances 109a, 109b are
substantially centered relative to their respective recesses 111a,
111b so that spacer 35' is substantially centered between posts
23a' 23b'. It will be appreciated that so long as each of said
protuberances are received anywhere within its respective recess,
spacer 35' will be properly positioned in a desired general
location between body members 17', 19'. It will be understood that
with each of the protuberances substantially centered with respect
to its respective recess, that the spacer will be located or
positioned in a nominal position relative to the body members, as
illustrated in FIGS. 27 and 28.
[0137] Further, it will be noted that the anterior end of the
spacer 35' abuts against (or is in relatively close proximity to)
the inner or posterior face of tab 103. In this manner, tab 103
cooperates with the anterior face of spacer 35' to as to prevent
anterior displacement of the spacer from its desired general
position between the body members 17', 19'. Because of the
interaction of the generally convex surfaces of the protuberances
and the concave surfaces of their respective recesses, spacer 35'
is effectively constrained against anterior, posterior, lateral,
and angled movement relative to the upper and lower body
members.
[0138] Further, as previously described, bone graft material (not
shown) is typically packed between the posterior face of implant
101 and the inner face of the posterior annulus substantially
filling the disc space DS such that bone graft material also aids
in preventing posterior movement of the spacer 35' relative to the
body members. Thus, it will be appreciated that tab 103, and the
cooperating generally rounded or part-spherical surfaces of
protuberances 109a, 109b and recesses 111a, 111b, and the bone
graft material prevent migration of the spacer 35' relative to the
implant body members 17', 19' not only immediately following
surgery, but also during normal use by the patient as the bone
graft material fuses the vertebrae together.
[0139] Referring now to FIGS. 29 and 30, the body members 17' and
19' are shown with spacer 35' laterally offset to the left such
that the left end of the spacer is in contact with stabilizing post
23a' and such that the protuberances 109a, 109b are disposed above
the extreme left-hand reaches of their respective recesses 111a,
111b. Upon retraction of the disc space DS and upon the application
of compression loads to the construct, the previously described
camming action of the convex protuberances engaging the concave
recesses cause the spacer to move or shift relative to the body
members and to be at least partially self-aligned and self-centered
with respect to the lower body members so as to be closer to its
nominal desired general location, as shown in FIGS. 27 and 29.
However, those skilled in the art will recognize that so long as
the protuberances are received within their respective recesses,
the spacer will be located within its desired general location and
that such location results in an acceptable insertion and location
of the spacer in implant 101.
[0140] This self-centering, self-aligning feature of the spacer 35'
means that upon installation of spacer 35' during the surgical
procedure, the surgeon need only place the implant 101 within the
disc space DS (as described above in regard to implant 1). With the
implant 101 so positioned, the surgeon then, using the
above-described distractor instrument, distracts body members 17'
and 19' and inserts spacer 35' within space 21' between the body
members. It will be appreciated that due to tab 103, the
stabilizing posts 23a', 23b', and the length of the spacer, the
spacer need only be positioned between the posts and somewhat to
the posterior of tab 103 such that upon removal of the distractor
instrument (which will allow retraction of the vertebrae) and upon
the application of a compressive load to the spinal column, the
above-described self-centering and self-aligning features of the
protuberances 109a, 109b and recesses 111a, 111b will move the
spacer from the position as shown in FIGS. 29 and 30 to the
substantially centered position of the spacer shown in FIGS. 27 and
28. Of course, if the spacer is shifted to the right, retraction
and the application of compressive loads will also self-center and
self-align the spacer. Additionally, if there is some angular
displacement of the spacer, the protuberances and recesses will
straighten the spacer relative to the body members in the same
manner.
[0141] Further, those skilled in the art will recognize that upon
application of compression loads (as herein described) and/or upon
the application of repeated micro-motion compressive spinal column
loads by the patient, as during sitting or walking, the cooperating
protuberances 109a, 109b and recesses 111a, 111b maintain the
self-alignment and self-centering of the spacer relative to the
upper and lower body members and prevent migration of the spacer
relative to the body members.
[0142] It will be further appreciated by those skilled in the art
that if during the surgical procedure a first spacer is inserted
within space 21' between the body members 17' and 19' and if it is
determined that the first spacer should be removed, the surgeon
need only insert the distractor blades of the distractor instrument
(not shown) into slots 31a', 31b' of the body members so as to
distract or expand space 21'. Then, the first spacer 31' may be
readily removed by gripping the spacer with a clamp and removing it
from between the body members and to withdraw the spacer through
the above-described incision 11 in the annulus 9, as shown in FIG.
4C. Then, a second spacer of, for example, a different (greater)
thickness, may be readily inserted.
[0143] As indicated at 113a, 113b in FIGS. 19-30, a pair of holes
is provided in spacer 35' so as to more readily permit the surgeon
to grasp the spacer by means of a clamp or other instrument so as
to enable the surgeon to maneuver the spacer within space 21'
between the body members 17', 19', or to remove the spacer.
[0144] It will be further appreciated that with the expandable
lumbar interbody or implant 1 of the present disclosure in its
collapsed height condition without spacer 35 installed between the
upper and lower body members 17, 19, it is easier for the surgeon
to insert the interbody into the disc space DS through the
annulotomy 11, and the interbody is more readily maneuverable by
the surgeon within the disc space so that the interbody spans the
apophyseal ring and so that the ends of the interbody are properly
inserted in the anterolateral annulotomies 15a. 15b, as generally
shown in FIG. 4. It will also be appreciated that with the
interbody 1 in its collapsed condition, it is much easier to remove
the interbody from the disc space.
[0145] Referring now to FIGS. 31-35, an alternative embodiment of
spacer 35' is shown and is indicated in its entirety at 35''. This
spacer 35'' is shown to have a pair of wings or extensions 115a,
115b, one on each end of the spacer, extending laterally from the
posterior side of the spacer. The anterior faces of these wings or
extensions bear against the posterior faces of respective posts
23a', 23b' so as to prevent anterior movement of the spacer 35''
beyond its predetermined position, as shown in FIGS. 33 and 35.
These wings are an alternative structure to or in addition to tab
103 for locating the spacer in anterior/posterior position relative
to the body member and for preventing anterior movement of the
spacer beyond a desired location. It will be further appreciated
that the length of each wing 115a, 115b is such that with the
spacer positioned within space 21' (as shown in FIG. 35) such that
one lateral side of the spacer bears against its respective post
23a' or 23b', the wing on the opposite lateral side of the spacer
still engages the posterior face of its respective post such that
both of the wings bear against their respective posts and thus
positively prevent insertion of the space in anterior direction
beyond a desired anterior position relative to the body members
17', 19'.
[0146] Thus, upon installation of the spacer 35'', the spacer need
only be oriented its protuberances 109a, 109b facing body member
17', with the wings 115a, 115b facing toward the posterior of the
implant 101, with the body of the spacer positioned between the
posts 23a, 23b'. Then upon retraction of the vertebrae spacing and
upon the application of compression loading to the implant 101, the
protuberances and the recesses will cooperate, as previously
described, so as to self-center and to self-align the spacer
relative to the body members. Further, with the protuberances
received in their respective recesses and with such normal
compression loads applied to the implant, the protuberances and
recesses will effectively prevent movement or migration of the
spacer relative to the body members. Still further, with bone graft
material (not shown) packed within the disc space DS on the
posterior side of implant 101, the bone graft material will also
aid the protuberances and recesses in preventing movement or
migration of the space from between the body members.
[0147] As shown best in FIG. 33, spacer 35'' has an oblique slot
117 extending part way through the upper or lower (or both) faces
of the spacer. This slot provides clearance for an operating blade
of a distractor to be inserted within the slot to aid in
positioning the spacer between the inner faces of the body members
of the implant. The slot 117 in the spacer is generally in register
with the slot 31a' or 31b' in its proximate body member.
[0148] Referring now to FIGS. 36-41, an alternative embodiment of
spacer 35' is shown and is indicated in its entirety at 35'''. This
spacer 35''' is shown to have a pair of wings or extensions
115a''', 115b''', one on each lateral end of the spacer, extending
laterally from the posterior side of the spacer. In addition, on
the right-hand end of the spacer (as shown in FIG. 36) has another
wing 115c''' spaced from wing 115b''' with the space therebetween
being sufficient so as to readily receive stabilizing post 23b'.
The anterior faces of wings or extensions 115a''', 115b''' bear
against the posterior faces of posts 23a', 23b' so as to prevent
anterior movement of the spacer 35''' beyond its predetermined
position, as shown in FIG. 4I. In addition the inner or posterior
face of wing 115c''' is positioned to engage against post 23b' so
as to prevent posterior movement of the spacer 35'''. It will be
further appreciated that the length of each wing 115a''', 115b''',
and 115c''' is such that with the spacer 35''' positioned within
space 21' (as shown in FIG. 4I) such that one lateral side of the
spacer bears against its respective post 23a' or 23b', the wing
115a''' or 115b''' on the opposite lateral side of the spacer still
engages the posterior face of its respective post such that both of
the wings bear against their respective posts and thus positively
prevent insertion of the spacer in anterior direction beyond a
desired anterior position relative to the body members 17',
19'.
[0149] As shown in FIG. 38, upon installation of spacer 35''', the
spacer is oriented at an oblique angle with respect to the implant
bodies 17', 19' when the implant bodies are positioned between
adjacent vertebrae and with the implant bodies distracted (as
generally shown in FIG. 4) so as to receive that spacer inserted
through an annulotomy 11 on the opposite side from that shown in
FIG. 4. As shown in FIG. 39, the spacer is moved diagonally between
body members 17', 19' until post 23b' is received between wings
115b''', 115c'''. Then, as shown in FIG. 4O, the spacer is rotated
so that the spacer 35''' is rotated clockwise about post 23b' (as
shown in FIG. 4O) until wing 115a''' bears against the posterior
surface of post 23a'. In this position, post 23b' is received
between wings 115b''' and 115c''' and wing 115''' bears against the
posterior surface of post 23a'.
[0150] It will be appreciated that if spacer 35''' is to be
inserted through an annulotomy 11 of the opposite side of the disc
from that shown in FIG. 4, the spacer 35''' would be oriented to be
a mirror image of the spacer 35''' shown in FIG. 38.
[0151] With spacer 35''' in the position shown in dotted lines in
FIG. 4I, the protuberances 109a, 109b are received in recesses
111a, 111b and the body of the spacer is positioned between the
posts 23a, 23b'. Then upon retraction of the vertebrae spacing and
upon the application of compression loading to the implant 101, the
protuberances and the recesses will cooperate, as previously
described, so as to self-center and to self-align the spacer
relative to the body members. Further, with the protuberances
received in their respective recesses and with such normal
compression loads applied to the implant, the protuberances and
recesses will effectively prevent movement or migration of the
spacer relative to the body members. Still further, with bone graft
material (not shown) packed within the disc space DS on the
posterior side of implant 101, the bone graft material will also
aid the protuberances and recesses in preventing movement or
migration of the space from between the body members. As noted, the
spaced wings 115b''', 115c''' substantially prevent both anterior
and posterior movement of the spacer relative to the body members
17', 19' beyond a predetermined limited amount of movement.
[0152] It will be further appreciated that implants 1 and 101 may
be provided in a range of widths, thicknesses, and lengths to
readily accommodate taller disc spaces DS and different vertebrae
sizes. For example, implants 1, 101 may have heights ranging
between 8.5 mm-10.0 mm, to accommodate taller or shorter disc
spaces DS and may have widths ranging between about 11-13 mm., and
lengths ranging between about 40-60 mm. to accommodate vertebrae
having a larger vertebrae footprint.
[0153] Referring now to FIGS. 42-59, three additional embodiments
of the implant of the present disclosure are illustrated in which
the upper and lower surfaces of the implant are angled (tapered
from rear to front) so as to provide options for encountered or
desired disc space lordosis. Specifically referring to the
embodiment shown in FIGS. 42-47, this is an expandable interbody or
implant, as indicated in its entirety by reference character 201.
The construction of this interbody or implant 201 is similar to the
embodiments discussed above and reference characters 217, 219, etc.
indicate parts having a similar construction and operation as
similar parts identified by similar reference characters 17, 19
etc. of the embodiment illustrated in FIGS. 1-41. Accordingly, only
the primary differences between implant 201 and the above-described
embodiments will be described in detail. In FIGS. 42-47, the
implant is shown in its collapsed or retracted condition with no
spacer 35 installed between the inner surfaces of the lower and
upper body members 217 and 219. However, it will be understood that
with the implant 201 inserted in disc space DS, as described above,
and with the lower and upper body members distracted, a spacer 35,
35', 35'', or 35''' may be inserted within space 221 between the
body members in the manner described above.
[0154] As perhaps best shown in FIG. 47, the upper face 237 of
upper body member 219 and the lower face 239 of lower body member
217 are angled or tapered from rear to front at a lordotic angle
LA. The lordotic angles of various implants 201 may range between
about 0.degree. and about 12.degree.. It will be appreciated that
the lordotic angles of the upper and lower body members may be
different. Thus, upon encountering a patient having disc space
lordosis, implants 201 having the desired lordotic angles LA, as
chosen by the surgeon, may be used so as to reconstruct the spine
by maintaining segmental lordosis, regional lordosis, and global
sagittal balance. More specifically, upon encountering a need to
improve the segmental or disc space lordosis, an implant 201 having
a desired predetermined lordosis angle LA may be installed in disc
space DS so that with the implant distracted, with an appropriate
spacer 35, 35', 35'', or 35''' installed in space 21 between the
lower and upper body members, with upper and lower faces 237, 239
of the implant engaging the cortical rims CR of the adjacent
vertebrae bodies, and with the angled, convex shape of the upper
and lower faces of the implant generally conforming to the disc
space and contacting the vertebrae endplates, upon distracting the
adjacent vertebrae bodies, the desired amount of lordotic
correction may be introduced in the reconstructed disc space. It
will be also appreciated that because the implant 201 is supported
by the cortical rims CR of the vertebrae bodies, there is less of a
tendency for subsidence to occur with a consequent loss of disc
space height to preoperative levels.
[0155] Referring now to FIGS. 49-53, still another embodiment of a
non-expandable or fixed height interbody implant in accordance with
the present disclosure is shown. This implant is indicated in its
entirety by reference character 301. As noted, implant 301 is
non-expandable or of fixed height and thus has a one-piece body 303
having an upper surface 305 and a lower surface 307. The rear face
of body 303 has a slot 309 therein similar to slot 31 of the above
embodiments so that the implant maybe inserted into the disc space
DS through annulotomy 11 and maneuvered within the disc space by
the surgeon so that the ends of the implant bear on the cortical
rims CR of the adjacent vertebrae bodies and such that the implant
is positioned generally similar to implant 1, as illustrated in
FIG. 4. It is also understood the slot 309 may be replaced by
another modification (not shown) of the fixed height implant
interbody implant that would allow a surgeon to use a tool to grasp
and maneuver the implant in the disc space. The upper and lower
faces 305 and 305 are angled or tapered in a manner similar to
implant 201 such that these upper and lower faces have a lordotic
angle LA, which may range from about 0.degree. to about 12.degree..
Of course, the lordotic angles LA of implant 301 may be used to
maintain or correct disc space lordosis in the same manner as
described in regard to implant 201.
[0156] Turning now to FIGS. 54-59, still another embodiment of the
present disclosure is illustrated in its entirety at 301'. This
implant 301' is similar to implant 301, as above described, except
that it has openings or fenestrations 311 formed therein that may
be packed with bone growth material so as to promote bone growth
and to aid in fusing the adjacent vertebrae. This augments the bone
graft material the surgeon places posterior to the implant for
fusing or permanently joining the vertebrae bodies above and below
the disc space. It will be understood that such fenestrations may
be incorporated in any of the embodiments of the implants of this
disclosure.
[0157] Referring now to the embodiment of the implant of the
present disclosure shown in FIGS. 60-65, this is essentially the
same as the implant shown in FIGS. 42-47 and this new embodiment is
indicated in its entirety by reference character 401. The various
features and parts of implant 401 correspond generally to the
corresponding to the features and parts of the body members and
spacers shown in FIGS. 42-47, except as particularly pointed out
and described below. The implant 401 has a lower body member 417
and an upper body member 419 with a spacer 435 positioned between
the inner faces of the upper and lower body members. Spacer 435 is
similar to spacer 35'' shown in FIGS. 33-36, except that it has an
oblique slot 436 (as best shown in FIG. 61) in one face of the
spacer that extends through the spacer from its posterior to its
anterior edge. Likewise, the lower body member and the upper body
member each have a respective oblique slot 431a, 431b in the inner
face of each body member that extends through the body from the
posterior to the anterior edge of the body member, with these slots
being generally in register with one another. As indicated at 421
for each of the slots 436, 431a, and 431b, the posterior portion of
these slots is preferably somewhat wider than the anterior portion
of the slot so as to aid in guiding a respective operating blade of
a distractor or other instrument into the slot, as will be more
particularly described below. It will be appreciated that the slot
436 in spacer 435 may be in the bottom face of the spacer, or slots
similar to slot 436 may be provided in both the upper and lower
faces of the spacer. It will also be appreciated that the slots
shown in FIGS. 60-63 are used when the incision 11 (as shown in
FIG. 4) is in the posterolateral portion of the annulus 9. However,
the angle of the oblique slots may be reversed if the incision 11
is on the contralateral side of the disc space. It will also be
appreciated that the lower and upper body members 417, 419 of
implant 401 may have their upper and lower faces formed to have the
lordotic angles LA, as shown in FIG. 47.
[0158] Further, spacer 435 may be provided with wings or
extensions, as indicated at 415a, 415b and 415c, to be similar in
construction and operation to wings 115a'''. 115b''', and 115c'''
heretofore described in relation to the embodiment shown in FIGS.
36-41.
[0159] Referring now to FIGS. 64 and 65, the lower body member 417
of implant 401 has been modified so as to facilitate capture of
posts 423a, 423b of the upper body member 419 by forming the lower
body member 417 in two pieces, as indicated at 417a, 417b. Each of
these body pieces has an alignment pin 451 extending from its inner
face to be received in a respective bore 453 in the opposite body
piece such that the two body pieces 417a, 417b can be fitted
together around posts 423a, 423b with the flange 429 on the
outermost end of the posts received in bores 425a, 425b with the
flange 429 positioned below the inwardly extending flange 427. With
each of the alignment pins 451 received in its respective bore 453,
the body pieces are in alignment with one another. A suitable
adhesive or the like may be used to permanently join the body
pieces once they are assembled.
[0160] Referring now to FIGS. 66-70, a distractor instrument, as
indicated in its entirety at 601, is illustrated having upper and
lower arms, as generally indicated at 603 and 605, made in
accordance with this disclosure. It will be appreciated that the
distractor is conventional and it has a parallelogram linkage, as
indicated generally at 607, such that upon compressing the handles
609, 611 toward one another, the operating arms or blades 603, 605
are distracted (moved apart) relative to one another and are
maintained in generally parallel relation. As is conventional,
distractor 601 has a return spring 610 to bias the handles apart
from one another and a curved rack 613 pivotally attached to one of
the handles and extending through an opening in the other handle
with the rack having a plurality of teeth 615 that cooperate with a
spring biased pawl 617 (as best shown in FIG. 68) carried by the
other handle such that the distractor will automatically lock each
time the handles are compressed a distance corresponding to the
pitch of the teeth on the rack. In this manner, when the surgeon
releases the handles, the distractor will be locked and the desired
distraction will be maintained. Of course, the pawl 617 may be
disengaged so as to allow retraction.
[0161] As best shown in FIGS. 66-70, the operating arms 603 and 605
angle obliquely relative to the handles 609, 611 at generally the
same oblique angle as the annulotomy incision 11 is positioned
within the annulus, as shown in FIG. 4. It will be appreciated that
such oblique angle of the operating arm positions the handles of
the distractor 601 out of the surgeon's field of view of the
operating site. The operating arms 603, 605 each have a respective
operating tip, as indicated at 621, 622, on their outer ends and
these operating tips are relatively thin and are generally parallel
to one another with a space or a gap 619 (as best shown in FIG. 68)
between the inner faces of the operating blades. In this
disclosure, the term "operating members" may refer to either
operating arms 603, 605 and/or to the operating tips 621, 622. With
the operating blades inserted into and through slots 431a, 431b of
an implant 401 positioned generally in the disc space DS (as shown
in FIG. 4), distractor 601 may be operated to distract both implant
401 and the disc space. With the implant and the disc space so
distracted, the obliquely oriented operating arms 603, 605 present
an opening formed by gap 619 (as best shown in FIGS. 68 and 70) so
as to receive the spacer 435. The spacer is guided by the inner
faces of the operating arms 603, 605 and by the inner faces of
operating blades 621, 622 as the spacer is moved into position
between the upper and lower implant bodies 419, 417, so that the
spacer may assume its position as generally shown in FIG. 4.
[0162] As shown best in FIG. 68, one of the thin operating blades
or tips 621 or 622 may have on its distal end a cleat or hook 623
on its distal end. This cleat may be on either the lower or the
upper operating tip, or such cleats may be provided on both the
upper and lower operating tips. With the distractor tips 621, 622
inserted through slots 431a and 431b of the lower and upper implant
body members 417 and 419, the cleat 623, which as shown in FIG. 68
is on the lower operating tip 622, engages the anterior face of the
lower body member 417 and the sides of the operating tips engage
the sides of the slots 431a. 431b and thus enable the surgeon to
engage the anterior face of the lower body member and the sides of
the upper and lower body members so that the implant may be readily
positioned between the vertebrae in a desired anterior-to-posterior
relation and in a desired lateral position generally corresponding
to the position of implant 1, as shown in FIG. 4, so that the
implant is at least in part supported on the cortical rim CR of the
vertebrae. It will be understood that because the posts 423a, 423b
are received in their respective bores 425a, 425b of the lower body
member 417 such that the upper and lower body members are readily
moved as a unit upon moving the distractor so as to position the
implant within the disc space DS. It will be also understood that
with cleat 623 on the lower operating tip 622, the slot 431a in the
lower body member may be somewhat deeper than the slot 431b in the
upper body member so as to accommodate cleat 623.
[0163] It will be further understood that as the distractor 601 is
operated so as to distract the implant and the adjacent vertebrae,
a considerable distraction force is applied to the operating arms
603, 605 and tips 621, 622 such that the operating arms and tips
may deflect and such that deflection may cause the implant to
become displaced from the operating tips. The cleat 623, however,
prevents the implant from moving toward the anterior relative to
the distractor and thus the cleat aids in keeping the implant in
its desired position as the implant and the disc space are
distracted. Further, the cleat and the fact that the operating arms
have a relatively good fit within slots 431a, 431b, allow the
surgeon to maneuver the implant within the disc space DS to the
position shown in FIG. 4. Further, it will be appreciated that the
upper and lower faces of tips 621 and 622 of operating arms or
blades 603, 605 engage their respective upper and lower body
members 419 and 417. Upon operation of distractor 601 by the
surgeon, both implant 401 and the disc space DS are distracted.
While the operating tips 621, 623 of distractor 601 may be used by
the surgeon to maneuver or position the implant 1 within the disc
space DS, it will be understood that within the scope of this
disclosure, the surgeon may use distractor 601 to distract the
adjacent vertebrae and the expandable implant and the surgeon may
use another instrument that hooks onto the implant so that it may
be readily maneuvered and positioned within the disc space.
[0164] As noted, the flared or enlarged ends 421 of slots 431a,
431b and 436 aid in guiding the operating blades into the slots. It
will be appreciated that the upper operating tip 621 may also have
a cleat similar to clear 623 (not shown) that extends upwardly. It
will be also realized that the thickness of the slots in the spacer
and in the upper and lower body members of implant 401 may be
appropriately sized to accommodate such upwardly facing cleat.
[0165] It will be appreciated that due to the length of the
operating arms 603, 605 and the relative thinness of the operating
tips 621, 622, and due to the relatively high forces necessary to
distract the vertebrae, it is preferable that the operating blades
and tips be made of a suitable high strength, high modulus of
elasticity material, such as a suitable stainless steel alloy, such
as Carpenter 465SS, so as to resist deflection. However, other
suitable materials may be used.
[0166] As described above, annulotomy incision 11 may be formed in
the contralateral posterolateral quadrant of the annulus 9. In such
case, the slots 436, 431a, and 431b in implant 401 would be
reversed from their positions shown in FIGS. 60-65 so that the
slots are generally along the axis of the annulotomy 11. In such
case, the distractor 601 would have the angle of its operating arms
603, 605 reversed from the angle shown in FIGS. 66-70. As shown in
FIG. 66, the arms 603 and 605 are removably secured to the
parallelogram linkage so that they may be installed and removed
without the use of tools (e.g., they may be snapped into position).
Thus, if it is desired to change the arms 603, 605 for other arms
that angle in the opposite direction from the position shown in
FIGS. 66-70, the new arms may be readily installed.
[0167] Referring now to FIGS. 71-75, after the surgeon has
installed an implant of the present disclosure, such as indicated
at 401, and after the surgeon has operated distractor 601 so as to
distract the disc space DS a first amount, a series of paddle blade
distractors of different widths, one of which is shown in FIG. 72
and which is generally indicated in its entirety at 701, may be
used to insure that the disc space DS and the upper and lower body
members 417, 419 of the implant 401 of this disclosure are
progressively distracted predetermined amounts corresponding to the
width of the particular paddle blade distractor being used until
the desired distraction is achieved and so that the operating arms
603, 605 and tips 621 and 622 of distractor 601 are maintained in a
generally parallel relation. For example, a set of four (4) paddle
blade distractors 701 may be used with each of the paddle blade
distractors having a paddle blade 703 with the width of the distal
end or operating tip 705 of each of the paddle blades 703 being
progressively wider, for example, 3 mm., 5 mm., 7 mm., and 9 mm.
Except for the width of the distal ends 705, these paddle blade
distractors are generally the same and thus only one will be
described in detail. The paddle blades 703 of each of the paddle
blade distractors 701 are of the same thickness (e.g., 2 mm.).
However, as noted above, the width of the distal end 705 of the
paddle blade constituting its operating end has a width
corresponding to one of the above-mentioned series widths. A
T-handle 707 is affixed to the proximal end 709 of the paddle blade
703. The proximal end 709 of each of the paddle blades has a width
greater than the width of its respective distal end or operating
tip 705 to provide maximum strength (resistance to torsion or
twisting) when the handle 707 is rotated by the surgeon. The sides
of the distal end 705 of the operating blade may either be parallel
(as shown in FIG. 72), or the sides may have a slight taper.
[0168] As shown best in FIG. 73, implant 401 without its spacer 435
installed is positioned in the disc space DS similar to its
position as shown in FIGS. 4 and 71. The operating arms 603, 605
and their corresponding operating tips 621, 622 of distractor 601
(as shown by bold lines) are inserted between the inner faces of
the upper and lower body members 419 and 417 of implant 401 of the
present disclosure. The distractor 601 is then operated so as to
distract (force apart) the lower and upper body members 417 and 419
and to distract the disc space DS between adjacent vertebrae (e.g.,
L3 and L4) a first increment. Then, as shown in FIG. 74, a first
paddle blade distractor 701 having the narrowest width (e.g., 3
mm.) operating blade 705 may be inserted into gap 619 between the
operating blades 603, 605 and their corresponding operating tips
621, 622 of distractor 601. The surgeon then rotates the T-handle
707 approximately 90.degree. (as shown in FIG. 75) so that the
edges of the operating tip or blade 705 bear against the inner
faces of the operating tips 621, 622 of distractor 601 thereby to
force the operating tips apart at least the width of operating
blade 705 (e.g., 3 mm.). As shown best in FIG. 75, because the
edges of the operating blade 705 are substantially parallel (or may
have a slight taper), as the paddle blade distractor 701 is rotated
about the longitudinal axis of blade 703, the side edges of the
operating tip 705 insure that the operating arms 603, 605 and the
relatively thin tips 621, 622 of distractor 601 are returned to a
parallel (or nearly parallel) condition if they deflected as the
distractor 601 was actuated. Those skilled in the art will
appreciate that when it is stated that the operating blade 705 is
inserted within gap 619 and when the operating blade 705 is rotated
about its longitudinal axis, the edges of the operating blade may
contact the inner surfaces of the operating arms 603, 605, or the
edges may or may not also contact the inner surfaces of operating
tips 621, 622. Likewise, if the edges of the operating blade bear
against the inner faces of the operating tips 621, 622, the edges
may or may not engage the inner surfaces of the operating arms 630,
605.
[0169] Then, the surgeon may further operate distractor 601 to
further distract the disc space and the upper and lower body
members of the implant an additional amount. The first paddle blade
distractor 701 is removed from between the upper and lower body
members 419 and 417 of implant 410 and a next wider paddle blade
distractor 701 having an operating blade somewhat wider (e.g., 5
mm.) may be inserted between the inner faces of operating arms 603
and 605 of distractor 601. As shown best in FIG. 75, this second
paddle blade distractor 701 is then rotated about 90.degree. so as
to insure that the upper and lower body members and the disc space
are distracted an amount at least as wide as the width of the next
wider paddle blade (e.g., 5 mm.) and to return the operating tips
621, 622 to a parallel relation. This process may be repeated until
the disc space has been sufficiently distracted to allow the
insertion of the appropriate spacer 435 of implant 401 of the
present disclosure. It will be understood that the operating tip
705 of the set of paddle blade retractors may have widths different
from the 3 mm., 5 mm., 7 mm., and 9 mm widths described above and
more or fewer paddle blade distractors 701 may be used in
accordance with this disclosure.
[0170] In accordance with the present disclosure, a method of
distracting and fusing a disc space between two adjacent vertebrae
bodies is described including the steps of making an incision in
the annulus at the desired level to access a disc space between the
adjacent vertebrae to be fused, where the incision is in a
posterior lateral quadrant of the annulus and the incision is of
sufficient length so as to permit the accommodate surgical
instrumentation for performing surgical procedures within the disc
space and so as to accommodate endoscopic instrumentation in the
disc space so as to enable visualization of the disc space for the
surgeon performing the surgical procedures. A discectomy of the
disc material is performed within the annulus via the incision in
the annulus under endoscopic viewing of the disc space. The
endplates of the adjacent vertebrae bodies are prepared under
endoscopic viewing of the disc space. It is understood that in
accordance with the present disclosure, the surgeon may elect to
perform surgical procedures within the disc space without
endoscopic visualization. The implant is inserted into the disc
space via the incision so as to extend substantially across the
vertebrae bodies in the anterior region of the vertebrae bodies.
And, the implant and the disc space are distracted a desired
amount. It will be understood that the order of the steps of the
above method (or any method described in the present disclosure)
may not be critical, but as the steps are described in this
disclosure, it is necessary to list one step before the other, but
in the performance of the method, it is not necessary that the
steps be performed in the order described.
[0171] As various changes could be made in the above constructions
and methods without departing from the scope of the disclosure, it
is intended that all matter contained in the above description or
shown in the accompanying drawings shall be interpreted as
illustrative and not in a limiting sense.
* * * * *