U.S. patent application number 11/475329 was filed with the patent office on 2006-10-26 for spinal implant.
Invention is credited to Gary Karlin Michelson.
Application Number | 20060241764 11/475329 |
Document ID | / |
Family ID | 22791197 |
Filed Date | 2006-10-26 |
United States Patent
Application |
20060241764 |
Kind Code |
A1 |
Michelson; Gary Karlin |
October 26, 2006 |
Spinal implant
Abstract
A spinal implant is disclosed which when placed within the
spinal disc space stabilizes the spinal segment.
Inventors: |
Michelson; Gary Karlin;
(Venice, CA) |
Correspondence
Address: |
MARTIN & FERRARO, LLP
1557 LAKE O'PINES STREET, NE
HARTVILLE
OH
44632
US
|
Family ID: |
22791197 |
Appl. No.: |
11/475329 |
Filed: |
June 27, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10292539 |
Nov 12, 2002 |
7066961 |
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11475329 |
Jun 27, 2006 |
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09580768 |
May 30, 2000 |
6478823 |
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10292539 |
Nov 12, 2002 |
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29056996 |
Jul 15, 1996 |
D425989 |
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09580768 |
May 30, 2000 |
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29023922 |
Jun 3, 1994 |
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29056996 |
Jul 15, 1996 |
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08052211 |
Apr 22, 1993 |
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29023922 |
Jun 3, 1994 |
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07546849 |
Jul 2, 1990 |
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08052211 |
Apr 22, 1993 |
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07212480 |
Jun 28, 1988 |
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07546849 |
Jul 2, 1990 |
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Current U.S.
Class: |
623/17.11 |
Current CPC
Class: |
A61F 2002/30158
20130101; A61F 2/30767 20130101; A61F 2002/4629 20130101; A61F
2/30744 20130101; A61F 2/44 20130101; A61F 2002/30579 20130101;
A61F 2002/30904 20130101; A61F 2002/30507 20130101; A61F 2002/30405
20130101; A61F 2002/30556 20130101; A61F 2002/30261 20130101; A61F
2230/0017 20130101; A61F 2002/30523 20130101; A61F 2230/0019
20130101; A61F 2002/30604 20130101; A61F 2220/0025 20130101; A61F
2002/30774 20130101; A61F 2220/0041 20130101; A61F 2210/0004
20130101; A61F 2002/30797 20130101; A61F 2002/30153 20130101; A61F
2230/0026 20130101; A61F 2/442 20130101; A61F 2/4455 20130101; A61F
2002/30062 20130101; A61F 2002/2835 20130101; A61F 2002/30143
20130101; A61F 2002/30841 20130101; A61F 2002/3092 20130101; A61F
2002/30843 20130101; A61F 2002/30433 20130101; A61F 2002/449
20130101; A61F 2002/3037 20130101; A61F 2220/0033 20130101; A61F
2/447 20130101; A61F 2250/0009 20130101; A61F 2/4611 20130101; A61F
2002/30599 20130101; A61F 2002/30398 20130101; A61F 2230/0082
20130101; A61F 2002/30836 20130101; A61F 2002/448 20130101; A61F
2002/4485 20130101; A61F 2002/30789 20130101; A61F 2002/30777
20130101; Y10S 606/907 20130101; A61F 2002/30785 20130101; A61F
2250/0063 20130101; A61F 2002/30593 20130101; A61F 2310/00796
20130101; A61F 2002/30787 20130101; A61F 2002/4627 20130101 |
Class at
Publication: |
623/017.11 |
International
Class: |
A61F 2/44 20060101
A61F002/44 |
Claims
1. A spinal fusion implant comprising: a leading end and a trailing
end opposite said leading end, said implant having a length from
said leading end to said trailing end, said trailing end having a
perimeter, said trailing end having a hole therein, said trailing
end having a slot portion intersecting one portion of the perimeter
of said trailing end, said trailing end having another slot portion
intersecting another portion of the perimeter of said trailing end
opposite said one portion of the perimeter of said trailing end;
opposite sides between said leading and trailing ends, said implant
having a width from one of said sides to the other of said sides,
said implant having a height; and an opening through said implant
and oriented along the height, said opening being between said
opposite sides and between said leading and trailing ends.
2. The implant of claim 1, wherein said slot portion and said
another slot portion are opposite ends of a slot having a length
and a width transverse to the length of said slot.
3. The implant of claim 2, wherein said hole has a diameter, the
width of said slot being greater than the diameter of said
hole.
4. The implant of claim 1, wherein said sides have at least one
opening in communication with said opening through the height of
said implant.
5. The implant of claim 1, wherein said implant comprises a second
opening through said implant and oriented along the height, said
second opening being between said opposite sides and between said
leading and trailing ends.
6. The implant of claim 1, wherein the height of said implant is
less than the width of said implant.
7. An artificial spinal fusion implant comprising: a leading end
and a trailing end opposite said leading end, said implant having a
length from said leading end to said trailing end; opposite sides
between said leading and trailing ends, each of said sides and said
trailing end having an upper portion, said implant having a maximum
width from one of said sides to the other of said sides, said
implant having a central vertical axis perpendicular to the length
and width of said implant, said implant having a height, said
implant having a maximum height less than the maximum width of said
implant; and an opening through said implant and oriented along the
height, said opening being between said opposite sides and between
said leading and trailing ends, said opening having an upper
portion between said upper portions of said opposite sides, said
upper portion of said opening having a minimum dimension transverse
to the central vertical axis of said implant that is greater than
the maximum height of said implant.
8. The implant of claim 7, wherein said opening has a central
longitudinal axis that is generally coaxial with the central
vertical axis of said implant.
9. The implant of claim 7, wherein said trailing end includes a
trough.
10. The implant of claim 9, wherein said trough includes a
hole.
11. The implant of claim 7, wherein one of said sides has at least
one opening in communication with said opening oriented along the
height of said implant, said at least one side opening having a
central longitudinal axis and a cross-sectional size transverse to
the central longitudinal axis of said at least one side opening,
the transverse cross-sectional size of said at least one side
opening being different from the transverse cross-sectional size of
said opening oriented along the height of said implant.
12. The implant of claim 7, wherein said implant has a cross
section along at least a portion of the length of said implant that
forms a quadrilateral.
13. The implant of claim 7, wherein said minimum transverse
dimension of said upper portion of said opening is greater than a
majority of the length of said implant.
14. An artificial spinal fusion implant comprising: a leading end
and a trailing end opposite said leading end, said implant having a
length from said leading end to said trailing end and a maximum
width perpendicular to the length; a top and a bottom between said
leading and trailing ends, said implant having a maximum height
from said top to said bottom, said implant having a central
vertical axis through said top and said bottom; a plurality of
openings in each of said top and said bottom; said top and said
bottom being spaced apart from one another to form an open area
therebetween, said openings in said top and bottom being in
communication with said open area; and the maximum width of said
implant being greater than the maximum height of said implant.
15. The implant of claim 14, wherein said implant has a cross
section along at least a portion of the length of said implant that
forms a quadrilateral.
16. The implant of claim 14, further comprising a material adapted
to fill at least a portion of one of said openings in said top.
17. The implant of claim 14, wherein one of said openings in said
top has a minimum dimension transverse to the central vertical axis
of said implant that is greater than a majority of the length of
said implant.
18. The implant of claim 14, wherein at least one of said openings
in said top and at least one of said openings in said bottom
overlap each other along a vertical line.
19. The implant of claim 14, wherein said top and said bottom are
generally parallel to one another.
20. The implant of claim 14, wherein said open area has a maximum
width transverse to the length of said implant, the maximum width
of said open area being greater than the maximum height of said
implant.
Description
[0001] The present application is a continuation of application
Ser. No. 10/292,539, filed Nov. 12, 2002, now U.S. Pat. No.
7,066,961; which is a continuation of application Ser. No.
09/580,768, filed May 30, 2000, now U.S. Pat. No. 6,478,823; which
is a continuation-in-part of application Ser. No. 29/056,996, filed
Jul. 15, 1996, now U.S. Pat. No. D425,989; which is a continuation
of application Ser. No. 29/023,922, filed Jun. 3, 1994, now
abandoned; which is a continuation of application Ser. No.
08/052,211, filed on Apr. 22, 1993, now abandoned; which is a
continuation of application Ser. No. 07/546,849, filed Jul. 2,
1990, now abandoned; which is a continuation of application Ser.
No. 07/212,480, filed Jun. 28, 1988, now abandoned; all of which
are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to an artificial fusion
implant to be placed into the intervertebral space left after the
removal of a damaged spinal disc.
[0003] The purpose of the present invention is to provide an
implant to be placed within the intervertebral disc space and
provide for the permanent elimination of all motion at that
location. To do so, the device is space occupying within the disc
space, rigid, self-stabilizing to resist dislodgement, stabilizing
to the adjacent spinal vertebrae to eliminate local motion, and
able to intrinsically participate in a vertebra to vertebra bony
fusion so as to assure the permanency of the result.
[0004] At present, following the removal of a damaged disc, either
bone or nothing is placed into the space left. If nothing is placed
in the space the space may collapse which may result in damage to
the nerves; or the space may fill with scar tissue and eventually
lead to a reherniation. The use of bone is less than optimal in
that the bone obtained from the patient requires additional surgery
and is of limited availability in its most useful form and if
obtained elsewhere, lacks living bone cells, carries a significant
risk of infection, and is also limited in supply as it is usually
obtained from young accident victims. Furthermore, regardless of
the source of the bone, it is only marginal structurally and lacks
a means to either stabilize itself against dislodgement, or to
stabilize the adjacent vertebrae.
[0005] A review of all possibly related prior art will demonstrate
the novelty of the present invention.
[0006] There have been an extensive number of attempts to develop
an acceptable disc prothesis (an artificial disc). Such devices by
design would be used to replace a damaged disc and seek to restore
the height of the interspace and to restore the normal motion of
that spinal joint. No such device has been found that is medically
acceptable. This group of prosthetic or artificial disc
replacements seeking to preserve spinal motion which are different
from the present invention include:
[0007] U.S. Pat. No. 3,867,728 STUBSTAD--describing a flexible disc
implant.
[0008] U.S. Pat. No. 4,349,921 KUNTZ--describing a flexible disc
replacement with rope or file like surface projections to
discourage device dislocation.
[0009] U.S. Pat. No. 4,309,777 PATIL--describing motion preserving
implant with spice outer surfaces to resist dislocation and
containing a series of springs to urge the vertebrae away from each
other.
[0010] U.S. Pat. No. 3,875,595 FRONING--describing a motion
preserving bladder like disc replacement with two opposed stud like
projections to resist dislocation.
[0011] U.S. Pat. No. 2,372,622 FASSIO (French)--describing a motion
preserving implant comprising complimentary opposed convex and
concave surfaces.
[0012] In summary then, these and other similar devices resemble
the present invention only in that they are placed within the
intervertebral space following the removal of a damaged disc. In
that they seek to preserve spinal motion, they are diametrically
different from the present invention which seeks to permanently
eliminate all motion at that spinal segment.
[0013] A second related area of prior art includes those devices
utilized to replace essentially wholly removed vertebra. Such
removal is generally necessitated by extensive vertebral fractures,
or tumors, and is not associated with the treatment of disc
disease, or therefore related to the present invention. While the
present invention is to be placed within the disc space, these
prior devices cannot be placed within the disc space as at least
one vertebra has already been removed and there no longer remains a
"disc space." Furthermore, all of these devices are limited in that
they seek to perform as temporary structural members mechanically
replacing the removed vertebra (not a removed disc), and do not
intrinsically participate in supplying osteogenic material to
achieve cross vertebrae bony fusion. Therefore, again unlike the
present invention which provides for a source of osteogenesis, use
of this group of devices must be accompanied by a further surgery
consisting of a bone fusion procedure utilizing conventional
technique. This group consisting of vertebral struts rather than
disc replacements would include the following:
[0014] U.S. Pat. No. 4,553,273 WU--describing a tumbuckle like
vertebral strut.
[0015] U.S. Pat. No. 4,401,112 REZAIAN--describing a turnbuckle
like vertebral strut with the addition of a long stabilizing staple
that spans the missing vertebral body.
[0016] U.S. Pat. No. 4,554,914 KAPP--describing a large
distractible spike that elongates with a screw mechanism to span
the gap left by the removal of a entire vertebrae and to serve as
an anchor for acrylic cement which is then used to replace the
missing bone (vertebrae).
[0017] U.S. Pat. No. 4,636,217 OGILVIE--describing a vertebral
strut mechanism that can be implanted after at least one vertebra
has been removed and which device consists of a mechanism for
causing the engagement of screws into the vertebra above the
vertebra below the one removed.
[0018] In summary then, this group of devices differs from the
present invention in that they are vertebral replacement struts, do
not intrinsically participate in the bony fusion, can only be
inserted in the limited circumstances where an entire vertebra has
been removed from the anterior approach, and are not designed for,
or intended to be used for the treatment of disc disease.
[0019] A third area of prior art related to the present invention
includes all devices designed to be applied to one of the surfaces
of the spine. Such devices include all types of plates, struts, and
rods which are attached by hooks, wires, and screws. These devices
differ significantly from the present invention in that they are
not inserted within the disc space, and furthermore do not
intrinsically participate in supplying osteogenic material for the
fusion.
[0020] Therefore, with these devices where permanent spinal
immobilization is desired an additional surgery consisting of a
spinal fusion performed by conventional means or the use of
supplemental methylmethacrylate cement is required. Such devices,
applied to the spine but not within the disc space, would include
the following: [0021] U.S. Pat. No. 4,604,995--STEPHENS--describing
a "U" shaped metal rod attached to the posterior elements of the
spine with wires to stabilize the spine over a large number of
segments. [0022] U.S. Pat. No. 2,677,369--KNOWLES--describing a
metal column device to be placed posteriorly along the lumbar spine
to be held in position by its shape alone and to block pressure
across the posterior portions of the spinal column by locking the
spine in full flexion thereby shifting the maximum weight back onto
the patient's own disc.
[0023] Other devices are simply variations on the use of rods (e.g.
Harrington, Luque, Cotrel-Dubosset, Zielke), wires or cables
(Dwyer), plates and screws (Steffee), or struts (Dunn,
Knowles).
[0024] In summary, none of these devices are designed for or can be
used within the disc space, do not replace a damaged disc, and do
not intrinsically participate in the generation of a bony
fusion.
[0025] Other prior art possibly related to the present invention
and therefore, to be considered related to "Bony Ingrowth". Patents
related to this feature describe either methods of producing
materials or devices to achieve the same. Such patents would
include: [0026] U.S. Pat. No. 4,636,526 (DORMAN), U.S. Pat. No.
4,634,720 (DORMAN), U.S. Pat. No. 4,542,539 (ROWE), U.S. Pat. No.
4,405,319 (COSENTINO), U.S. Pat. No. 4,439,152 (SMALL), U.S. Pat.
No. 4,168,326 (BROEMER), U.S. Pat. No. 4,535,485 (ASHMAN), U.S.
Pat. No. 3,987,499 (SCHARBACH), U.S. Pat. No. 3,605,123 (HAHN),
U.S. Pat. No. 4,655,777 (DUNN), U.S. Pat. No. 4,645,503 (LIN), U.S.
Pat. No. 4,547,390 (ASHMAN), U.S. Pat. No. 4,608,052 (VAN KAMPEN),
U.S. Pat. No. 4,698,375 (DORMAN), U.S. Pat. No. 4,661,536 (DORMAN),
U.S. Pat. No. 3,952,334 (BOKROS), U.S. Pat. No. 3,905,047 (LONG),
U.S. Pat. No. 4,693,721 (DUCHEYNE), U.S. Pat. No. 4,070,514
(ENTHERLY).
[0027] However, while the present invention would utilize bone
ingrowth technology, it would do so with conventional
technology.
[0028] The final area of related prior art to be considered is that
of devices designed to be placed within the vertebral interspace
following the removal of a damaged disc, and seeking to eliminate
further motion at that location.
[0029] Such a device is contained in U.S. Pat. No. 4,501,269--BAGBY
describing an implantable device, limited instrumentation, and a
method; whereby a hole is bored transversely across the joint and
then a hollow metal basket of larger diameter is then pounded into
the hole and then filled with the bone debris generated by the
drilling. The present invention differs from the prior art devices
in the following ways: [0030] 1. UNIVERSAL APPLICABILITY WITHOUT
CONTOURING OF THE INTERSPACE. The present device will fit any
patient, anywhere throughout the spine, in any intervertebral disc
space, and without alteration of that interspace regardless of its
natural size or shape. [0031] 2. RESTORATION AND PRESERVATION OF
THE INTERSPACE. The present invention will restore the
intervertebral space to its premorbid dimensions, and do so by
having the implant fit the space rather than having to modify the
interspace, by bone removal from the vertebrae, to accommodate the
implant. [0032] 3. END PLATE PRESERVATION. Preservation of the
highly specialized weight bearing cortical bone is allowed and end
plate perforation into the highly vascular cancellous bone marrow
with its attendant bleeding is avoided. Such bleeding, when it
occurs, bears all the risks of blood loss (e.g. hypovolemic shock,
transfusion transmitted diseases such as hepatitis and acquired
immune deficiency syndrome, etc.), and all the complications
arising from the resultant impaired visualization of the vital
structures (e.g. nerves, blood vessels, and organs) due to such
bleeding. [0033] 4. TECHNIQUE. The technique for insertion of these
implants is consistent with the established methods of disc
removal, and requires neither specialized instrumentation nor
specialized surgical technique. [0034] 5. EXTENT OF DISC REMOVAL.
The extent of disc removal can be determined by the surgeon at the
time surgery and can be individualized for each patient. [0035] 6.
NO DRILLING. No drilling is involved with the use of the present
invention. [0036] 7. ELIMINATION OF INCORRECT IMPLANT SIZE
SELECTION. In those implant systems where a drill is used and
significant bone is removed then an estimate of the implant size
must first be made, and then, regardless of the fit, an implant at
least as large as the space created by the drilling must be
utilized, regardless of the quality of that fit. With the present
invention no significant bone is removed, and the correct size
implants are fitted directly to the interspace eliminating the need
to guess at the correct implant size before the fact. [0037] 8.
MODULAR DESIGN. The present implants are available in varying
lengths to accommodate the changing depths of the interspace from
central to lateral. The devices are available in varying heights or
are infinitely adjustable as to the height within the physiological
range. The widths are standardized, and the various embodiments can
be used in any combination (e.g. in the lumbar spine two
auto-expanding implants could be used in conjunction with two
anchor deploying implants to completely fill the interspace).
[0038] 9. AVOIDANCE OF SIZE LIMITATIONS. Because in one embodiment
the system is modular, component parts can be inserted through a
very small opening until a much larger implant is reconstituted
completely filling the available interspace; and yet much larger
when assembled than the opening through which the component modular
sections were introduced. For example, in the lumbar spine four
implants introduced one at a time and measuring 8 mm in width,
would when reconstituted within the interspace constitute a 32 mm
wide implant. Implantation of a single implant of those dimensions
from a posterior approach in the lumbar spine would otherwise be
impossible because of the presence of the dural sac and spinal
nerves. [0039] 10. THE AVOIDANCE OF INTERSPACE COLLAPSE. The device
is many times stronger than bone and will not collapse. The
implantation of the device allows preservation of the very strong
vertebral cortex, which is resistant to compression preventing the
migration of the implant into the vertebrae. The large surface area
of the assembled modular implant, minimizes the load per unit area.
For example, a reconstituted lumbar implant of four modular
components would have the weight distributed over approximately 8
sq. cm. per vertebral interface. [0040] 11. REMOVABILITY. Because
the present invention is an interspace implant and not a "through
vertebrae" cross interspace implant, removal of the implant, should
that become necessary, would not result in iatrogenic destruction
of the adjacent vertebrae. [0041] 12. SELF-STABILIZING. The implant
is self-stabilizing without the use of threads. All of the implants
are surface configured to resist dislodgement and the preferred
embodiments contain active, mechanical means to assure permanent
anchoring. Long term stability begins with the above and is further
enhanced by surface treating of the implant for bone ingrowth (by
known conventional means) and osteogenically loading the implants.
[0042] 13. SPINE REDUCING. Various embodiments of the present
invention such as the ones with the 180 degree opposed ratcheted
surface, and the auto-expanding type, are capable of reducing a
vertebral listheses (a forward or backward translation of one
vertebrae upon another). [0043] 14. SPINAL STABILITY. These
implants are capable of stabilizing a spinal segment following disc
removal, and do so without the use of threads (threads would by
design need to violate the vertebrae themselves extensively).
[0044] 15. SAFETY. The entire procedure is performed under direct
vision and with complete visualization of the adjacent vital
structures (e.g. organs, neural structures and blood vessels).
[0045] In summary then, the present invention is an interspace
implant utilized to replace a damaged disc, which unlike an
artificial disc, seeks to permanently eliminate rather than to
preserve spinal motion, and to do so by a bony fusion. The present
invention is clearly an improvement over the prior art providing an
interspace implant intrinsically participating in the fusion
process, self-stabilizing, stabilizing to the spinal segment,
consistent with conventional methods of discectomy, and uniquely
consistent with the preservation of the integrity of the adjacent
vertebrae.
BRIEF SUMMARY OF THE PRESENT INVENTION
[0046] The present invention comprises an artificial implant, the
purpose of which is to participate in, and directly cause bone
fusion across an intervertebral space following .the excision of a
damaged disc. Said implants are structurally load bearing devices,
stronger than bone, capable of withstanding the substantial forces
generated within the spinal interspace. Such devices have a
plurality of macro sized openings of 13 mm, which can be loaded
with fusion promoting materials, such as autogenous bone, for the
purpose of materially influencing the adjacent vertebrae to perform
a bony bond to the implants and to each other. The implant casing
may be surface textured or otherwise treated by any of a number of
known technologies to achieve a "bone ingrowth surface" to further
enhance the stability of the implant and to expedite the fusion.
Further, said devices are so configured and designed so as to
promote their own stability within the vertebral interspace to
resist dislodgement, and furthermore, to stabilize the adjacent
vertebrae.
[0047] To use the implant of the present invention a conventional
discectomy is performed and the vertebral endplates scraped, but
not perforated. The appropriately sized implants are loaded with
autogenous bone and implanted within the interspace.
[0048] For example for an anterior cervical device implantation, a
short transverse incision is made across the front of the neck and
to the right of the midline directly over the diseased disc. The
platysma muscle is split, and the sternocleidomastoid muscle with
the carotid sheath is protected and retracted laterally. The
esophagus, trachea and associated midline structures are protected
and retracted medially, thus exposing the anterior aspect of the
cervical spine. The diseased disc is identified and removed by
conventional surgical methods. The adjacent vertebral endplates are
gently scraped free of any remaining cartilage until diffuse fine
punctuate decortication is achieved. The dimensions of the
interspace are then measured In mold distraction, and the
appropriate implant selected. Cancellous bone, obtained from the
patient's iliac crest or the equivalent, is loaded into the
implant. The safety driver is then utilized to insert the implant
behind the anterior lips of the vertebrae. The wound is then closed
in the routine manner.
OBJECTS OF THE PRESENT INVENTION
[0049] It is an object of the present invention to provide for a
means of achieving interspace fusion and stabilization as a single
procedure by a means consistent with the conventional method of
discectomy.
[0050] It is another object of the present invention to provide for
a means of achieving an interspace fusion and stabilization that is
quicker, safer, and entails less blood loss than by any other known
means.
[0051] It is another object of the present invention to provide for
a means of achieving a one stage interspace fusion and
stabilization without significant violation or removal of the
adjacent vertebral bone stock.
[0052] It is another object of the present invention to provide for
a method of intervertebral arthrodesis and stabilization of
enhanced safety where the entire procedure is performed under
direct vision.
[0053] It is another object of the present invention to provide for
a method of intervertebral arthrodesis and stabilization of greater
simplicity and requiring minimal specialized instrumentation or
technique not already possessed by those doing such procedures by
conventional means.
[0054] It is another object of the present invention to provide for
a modular prosthesis, allowing complimentary subunits to be
inserted individually through a small opening and to then be
reassembled within the interspace, so as to reconstitute an
interspace occupying device much larger than would be insertable as
a whole.
[0055] It is another object of the present invention to provide for
a modular implant system such that it is possible to precisely fit
the contours of any interspace without the need to sacrifice any
vertebral bone to accommodate the prosthesis. These and other
objects of the present invention will be apparent from review of
the following specifications and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0056] FIG. 1 is a top right perspective view of the implant
(cervical type).
[0057] FIG. 1a is a front view of the implant of FIG. 1
[0058] FIG. 1b is a rear view of the implant of FIG. 1.
[0059] FIG. 1c is a top view of the implant of FIG. 1.
[0060] FIG. 1d is a side view of the implant of FIG. 1.
[0061] FIG. 1e is a bottom view of the implant of FIG. 1.
[0062] FIG. 2 is a side sectional view of the implant viewed along
lines 2-2 of FIG. 1 d.
[0063] FIG. 3 is the implant FIG. 1 showing the attachment to the
driver and driver.
[0064] FIG. 4 is a front perspective view showing the implant being
driven into the disc space.
[0065] FIG. 4a is a front perspective view of the implant located
in the spine.
[0066] FIG. 5 is a side view of the implant in the spine attached
to the driver.
[0067] FIG. 5a is a close up partial sectional view of the implant
and driver.
[0068] FIG. 6 is a perspective view of a series of implants placed
in a lumber intervertebral space.
[0069] FIG. 6A is an alternative embodiment of a rectangular solid
implant.
[0070] FIG. 7 is a side sectional view of the vertebrae and implant
viewed along lines 7-7 of FIG. 6.
[0071] FIG. 7A is a side sectional view of the vertebrae structure
showing a third embodiment of the rectangular solid implant in
place.
[0072] FIG. 8 is an exploded perspective view of another embodiment
of the present invention.
[0073] FIG. 9 is a side sectional view of the vertebrae structure
and implant viewed along lines 9-9 of FIG. 8.
[0074] FIG. 10 is a side sectional view of the implant of FIG. 8,
in a contracted position.
[0075] FIG. 11 is a side sectional view of the implant of FIG. 10,
in an expanded position.
[0076] FIG. 12 is a perspective view of an alternative embodiment
of the implant of FIG. 9.
[0077] FIG. 13 is an alternative embodiment of a hollow rectangular
solid implant.
[0078] FIG. 14 is a cross sectional view of the hollow rectangular
solid implant of FIG. 13 viewed along lines 14-14 of FIG. 13.
[0079] FIG. 15 is an alternative embodiment of an expandable
implant in its extended position.
[0080] FIG. 16 is an expandable implant of FIG. 15 in its retracted
position.
[0081] FIG. 17 is an expandable implant of FIG. 16 located in the
disc space.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0082] Referring to FIGS. 1 through 5 an implant for use in the
disc space and associated apparatus used for inserting the implant
10 is shown. The implant 10 is shown as a substantially rectangular
hollow configuration, having a tapered forward portion.
[0083] The implant 10 has an upper surface 12 and a parallel lower
surface 14. The two side walls 16 and 18 are parallel to one
another and have a series of small sized openings 20 of 1 mm 3 mm
through the side walls 16 and 18.
[0084] The front wall 22 is slightly convex and has a depressed
portion 24 with a central threaded opening 26 for receiving the
engaging end 28 of a driving member 30.
[0085] The upper surface 12 has a threaded cap 32, which has
opening 33 there through, with a central wrench opening 34 for
engagement with an ALLEN hex key wrench A of FIG. 3. The cap 32
covers the opening into the hollow implant 10 and permits the
insertion of autogenous bone material into the hollow portion of
the implant 10. The cap 32 is surrounded by a series of small sized
openings 36 of 1 mm to 3 mm passing through the upper surface and
into the central hollow portion of the implant 10.
[0086] The rear wall 38 is convex so as to conform to the rear of
the disc space.
[0087] The driving member 30, shown in FIG. 3, comprises a
substantially hollow tubular member 40 having a long internal rod
42 having a turning knob 44 at one end and a threaded portion 46 at
the other end for threadably engaging the threaded opening 26 of
the implant 10. The engaging end 28 of the driving member 30 has a
slightly convex surface to complement the slightly convex surface
of the front wall 22. The engaging end 28 has an extension 48 for
fitting within the depressed portion 24 on the front wall 22 of the
implant 10. The engaging end 28 also has restriction members 47 and
49 to restrict the depth of penetration of the driver 30.
[0088] In use, the cap 32 is removed from the implant 10 and
autogenous bone material is inserted into the hollow portion of the
implant 10. The cap is then replaced. Various methods of packing
the implant 10 with the autogenous bone material may be used to
obtain a completely packed implant 10.
[0089] Referring to FIGS. 4, 4a, 5 and 5a, the method of inserting
the implant is shown. The threaded end 46 of the internal rod 42 of
the driving member 30 is attached to the threaded opening 26 of the
implant 10 by turning of the knob 44. Once the engaging end 28 is
in place, the fitting of the extended portion 48 into the depressed
portion 24 prevents movement of the implant 10 in relationship to
the driving member 30.
[0090] The implant is then placed at the entrance to the disc space
between the two adjacent vertebrae V. The knob 44 is then tapped
with hammer 11 sufficiently hard enough to drive the implant 10
into the disc space. The restriction members 47 and 49 which are
wider than the disc space, prevent over penetration of the
implant.
[0091] The size of the implant 10 is substantially the same size as
the disc space that it is replacing and thus will be larger or
smaller depending on the disc space in which it is to be used. In
the preferred embodiment the implant 10 is approximately 13 mm
wide.
[0092] Referring to FIGS. 4A and 5 the implant 10 is shown in place
in the disc space after removal of the driving member once the
implant was inserted in place.
[0093] The autogenous bone material that was packed within the
hollow portion of the implant 10 serves to promote bone ingrowth
between the implant and the adjacent vertebrae. Once the bone
ingrowth occurs, the implant 10 will be a permanent fixture
preventing dislodgement of the implant as well as preventing any
movement between the adjacent vertebrae.
[0094] Referring to FIG. 6 an alternative embodiment of the implant
is disclosed. The implant 61 comprises a substantially rectangular
member having a series of ridges 62 on the upper and lower surfaces
of the implant 60. One or more grooves 64 are placed on the upper
and lower surfaces as well. As indicated in FIG. 6, a series of
such implants 61 are used as the interbody spinal implant, each
placed closely adjacent one another to approximate the size of the
removed disc. A series of micro sized openings 63 perforate the
implant 61, to promote bone ingrowth.
[0095] The implant of FIG. 6 is inserted as follows: the disc is
substantially removed by conventional means. The implants 61 are
then inserted in the intervertebral space between the two
vertebrae.
[0096] The size of the implant 61 of FIG. 6 is approximately 26
millimeters in length and is wide enough so that four of them will
substantially fill the intervertebral space, depending on which
vertebras are fused.
[0097] In FIG. 6a a "bullet nosed" implant 67 having a open front
portion 69 to facilitate insertion of implant 67 is shown.
[0098] Referring to FIGS. 7 and 7a alternative embodiments of the
implant 61 of FIG. 6 is shown in place between two vertebrae V.
[0099] In FIG. 7 the implant 70 is shown with the ridges 62 shown
in the form of teeth facing the anterior. These ridges serve to
prevent the implant 60 from `walking` out of the space between the
vertebrae.
[0100] In FIG. 7a an embodiment of the implant 70 of FIG. 6 is
shown having opposed ridges 72 and 74. This serves to maintain the
alignment of the vertebrae when the two vertebrae V are improperly
aligned with respect to one another.
[0101] Referring to FIG. 8 an adjustable implant 81 having means
for adjusting the width of the implant 81 is shown. The implant 81
comprises a lower member 82 and an upper member 84 which when
fitted together form an essentially rectangular implant. The upper
member 84 and the lower member 82 have hollow portions that face
one another and receive tapered wedges 86 and 88 that fit within
the hollow portion of the upper and lower members 82 and 84. The
wedges 82 and 84 are such that at their large and they are higher
than the combined hollow space between the upper and lower members
84 and 82, and shallower at the other end than the hollow space
between the upper and lower members.
[0102] The wedges 86 and 88 have a central threaded opening 90 and
92 in alignment with each other for receiving threaded screw 94.
Deformable burrs 95 on the head 98 of the screw 94 are used for
locking the screw in place. The implant has a series of holes 100
throughout the body of the implant to assist in the ingrowth
process.
[0103] Referring to FIGS. 9 through 11 the expandable implant 81 is
shown positioned between the two vertebrae V. In FIG. 10 the
expandable implant 81 is illustrated in its contracted position.
The wedges 86 and 88 abutt the interior sloped surfaces 104 of the
upper and lower members 82 and 84.
[0104] As the screw 94 is turned, as shown in FIG. 11, the wedges
86 and 88 are drawn together, and the sloped portions of the wedges
force the upper member 82 away from the lower member 84. Once the
screw 94 has been turned sufficiently, the screw head 98 is hit,
causing the deformable burrs to be crimped so as to prevent the
reverse rotation of the screw 94.
[0105] In FIG. 12, another alternative embodiment of the expandable
implant 81 is illustrated with spike projections 106 extending from
the top and bottom members to dig into the vertebrae and assist in
maintaining it in place.
[0106] In use, the disc is removed, and the implant 81 is placed
between the vertebrae. The screw 94 is then turned expanding the
implant. In the preferred embodiment, the width is from 8
millimeters to 18 millimeters.
[0107] Referring to FIGS. 13 and 14, another alternative embodiment
of the invention is shown in which the implant 200 comprises a
rectangular hollow member having a slightly tapered forward section
202. The cross section, shown in FIG. 14, shows the rectangular
configuration of the implant.
[0108] In use of the implant the interior of the implant is filled
with a paste made of autogenous bone, and inserted in the place of
the former disc. The strength of the material used to make the
implant is such that, even though it is substantially hollow, it
does have sufficient strength to withstand the forces of the
vertebrae compressing the implant.
[0109] Referring to FIGS. 15 17, another alternative embodiment is
shown in which the implant has movable projections which are
movable from a first position within the implant to a second
position extending outside of the implant.
[0110] The implant 300 is of a generally rectangular configuration.
The top surface 302 and the bottom surface 304 of the implant have
slots 306 for permitting pivotal member 307 having spikes 308 at
their ends to project through said slots 306. The spikes 308 are
pinned at one end 310 within the implant 300.
[0111] Opposing wedge shaped members 312 and 314 having a central
threaded opening 316 for receiving a threaded screw 318 having a
head 320 and a slot 322. The wedges are facing each other so that
upon turning of the screw will draw the two wedges together,
causing the wedges to cause the spikes 308 to pivot about their end
310 and cause the spikes to project out of the implant through the
aligned slots 306. The depressions 329 in the pivotal member 307
engage the wedges 314 and 312 to lock the pivotal members 307 in
place. A series of holes 324 for promoting bone ingrowth and fusion
are provided in the implant 300.
[0112] In use, after the removal of the disc material, the implants
with the spikes 308 in their withdrawn position, are inserted into
the disc space. Then the screw 318 is turned until the spikes 308
are forced to enter the vertebrae material, as shown in FIG. 17.
The implant 300 is thus held firmly in place.
[0113] These implants have a surface configuration so as to induce
bone ingrowth through the implant, and into the wall of the
vertebrae in effect inducing fusion from one vertebrae V to the
other, thereby eventually making the implant itself superfluous as
the bone would do the work.
[0114] The implant itself, because of its being made of stronger
material than bone, would provide structural support to the two
vertebrae while awaiting bone ingrowth. Once the bone ingrowth
occurred, however, the implant would be firmly and permanently
fixed in place.
[0115] While the invention has been described with regards to the
preferred embodiment and a number of alternative embodiments, it is
recognized that other embodiments of the present invention may be
devised which would not depart from the scope of the present
invention.
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