Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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SPINE DISTRACTION IMPLANT AND METHOD
fntroduction=
This application is a combination of two U.S. Patent
applications, both entitled SPINE DISTRACTION IMPLANT AND
METHOD, having Serial no. 08/778,093 issued to U.S. Patent
5,836,948 on November 17, 1998 and U.S. Serial No. 08/958,281
issued to U.S. Patent 5,860,997 on June 19, 1999.
Background of the Invention:
As the present society ages, it is anticipated that there will be
an increase in adverse spinal conditions which are characteristic of
older people. By way of example, with aging comes increases in spinal
stenosis (including but not limited to central canal and lateral stenosis),
the thickening of the bones which make up the spinal column and
facet arthropathy. Spinal stenosis is characterized by a reduction in
the available space for the passage of blood vessels and nerves. Pain
associated with such stenosis can be relieved by medication and/or
surgery. Of course, it is desirable to eliminate the need for major
surgery for all individuals and in particular for the elderly.
Accordingly, there needs to be developed procedures and
implants for alleviating such condition which are minimally invasive,
can be tolerated by the elderly and can be performed preferably on an
outpatient basis.
Summary of the Invention:
The present invention is directed to providing a minimally
invasive implant and method for alleviating discomfort associated with
the spinal column.
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The present invention provides for apparatus and method for
relieving pain by relieving the pressure and restrictions on the
aforementioned blood vessels and nerves. Such alleviation of pressure
is accomplished in the present invention through the use of an implant
and method which distract the spinous process of adjacent vertebra in
order to alleviate the problems caused by spinal stenosis and facet
arthropathy and the like. While the implant and method particularly
address the needs of the elderly, the invention can be used with
individuals of all ages and sizes where distraction of the spinous
process would be beneficial.
In one aspect of the invention, an implant is provided for
relieving pain comprising a device positioned between a first spinous
process and a second spinous process. The device includes a spinal
column extension stop and a spinal column flexion non-inhibitor.
In another aspect of the invention, the implant is positioned
between the first spinous process and the second spinous process and
includes a distraction wedge that can distract the first and second
spinous processes as the implant is positioned between the spinous
processes.
In y.et another aspect of the present invention, the implant
includes a device which is adapted to increasing the volume of the
spinal canal and/or the neural foramen as the device is positioned
between adjacent spinous processes.
In yet a further aspect of the present invention, a method is
presented for relieving pain due to the development of, by way of
example only, spinal stenosis and facet arthropathy. The method is
comprised of the steps of accessing adjacent first and second spinal
processes of the spinal column and distracting the processes a
sufficient amount in order to increase the volume of the spinal canal
in order to relieve pain. The method further includes implanting a
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device in order to maintain the amount of distraction required to relieve
such pain.
In yet a further aspect of the invention, the method includes
implanting a device in order to achieve the desired distraction and to
maintain that distraction.
In yet a further aspect of the invention, the implant includes a
first portion and a second portion. The portions are urged together in
order to achieve the desired distraction.
In still a further aspect of the invention, the implant includes a
distracting unit and a retaining unit. The distracting unit includes a
body which can be urged between adjacent spinous processes. The
body includes a slot. After the distracting unit is positioned, the
retaining unit can fit into the slot of the retaining unit and be secured
thereto.
Other implants and methods within the spirit and scope of the
invention can be used to increase the volume of the spinal canal
thereby alleviating restrictions on vessels and nerves associated
therewith, and pain.
Brief Description of the Figures
Figs. 1 and 2 depict an embodiment of an implant of the
invention which is adjustable in order to select -the amount of
distraction required. Fig. 1 depicts the implant in a more extended
configuration than does Fig. 2.
Figs. 3a and 3b depict side and end views of a first forked and
of the embodiment of Fig. 1.
Figs. 4a and 4b depict side sectioned and end views of an
interbody piece of the implant of Fig. 1.
Figs. 5a and 5b depict side and end views of a second forked
end of the embodiment of Fig. 1.
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Figs. 6, 7, 8, 9 and 10 depict apparatus and method for another
embodiment of the present invention for creating distraction between
adjacent spinous processes.
Figs. 11, 12 and 13 depict yet a further embodiment of the
invention for creating distraction between adjacent spinous processes.
Figs. 14 and 15 depict a further apparatus and method of an
embodiment of the invention for creating distraction.
Figs. 16, 16a, and 17 depict yet another embodiment of the
present invention.
Figs. 18, 19 and 20 depict yet a further apparatus and method
of the present embodiment.
Figs. 21 and 22 depict still a further embodiment of the present
invention.
Figs. 23, 24 and 25 depict another embodiment of the present
invention.
Figs. 26, 27 and 28 depict another embodiment of the
invention.
Figs. 29 and 30 depict side elevational views of differently
shaped implants of embodiments of the present invention.
Figs,. 31, 32 and 33 depict various implant positions of an
apparatus of the present invention.
Figs. 34 and 35 depict yet another apparatus and method of the
present invention.
Figs. 36, 37 and 38 depict three different embodiments of the
present invention.
Figs. 39 and 40 depict yet another apparatus and method of an
embodiment of the present invention.
Figs. 41, 42 and 43 depict yet further embodiments of an
apparatus and method of the present invention.
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Fig. 44 is still a further embodiment of an implant of the
invention.
Fig. 45 is yet another depiction of an apparatus and method of
the invention.
Figs. 46 and 47 depict still a further apparatus and method of
an embodiment of the invention.
Figs. 48, 49, 50 and 51 depict yet a further apparatus and
method of the invention.
Figs. 52, 53, 54, 55a and 55b depict another apparatus and
method of the invention.
Figs. 56, 57 and 58 depict yet a further apparatus and method
of the invention.
Figs. 59 and 60 depict still a further embodiment of the
invention.
Fig. 61 depict another embodiment of the invention.
Figs. 62 and 63 depict yet another embodiment of the present
invention.
Figs. 64 and 65 depict still a further embodiment of the present
invention.
Fig. 6-6 depicts another embodiment of the invention.
Figs. 67 and 68 depict yet another embodiment of the present
invention.
Figs. 69, 70, 71 and 71 a depict a further embodiment of the
present invention.
Figs. 72 and 73 depict still another embodiment of the
invention.
Figs. 74, 75, 76, 77, and 78 depict still other embodiments of
the invention.
Figs. 79, 80, 80a, 81, 82, 83, 83a, 84, 85, 86 and 87 depict
still a further embodiment of the present invention.
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Figs. 88, 89, 90 and 91 depict yet another embodiment of the
present invention.
Detailed Description of the Preferred Embodiment
Embodiment of Figs. 1-5a. 5b
A first embodiment of the invention is shown in Figs. 1-5a, 5b.
Implant 20 includes first and second forked ends 22 and 24, each
defining a saddle 26, 28 respectively. The forked ends 22, 24 are
mated using an interbody piece 30. As can be seen in Figs. 3a, 3b,
the first forked end 22 includes a threaded shaft 32 which projects
rearwardly from the saddle 26. The threaded shaft 32 fits into the
threaded bore 34 (Fig. 4a) of the interbody piece 30.
The second forked end 24 (Figs. 5a, 5b) includes a smooth
cylindrical shaft 36 which can fit into the smooth bore 38 of the
interbody piece 30.
Fig. 1 shows the implant 20 in a fully extended position, while
Fig. 2 shows the implant in an unextended position. In the unextended
position, it can be seen that the threaded shaft 32 of the first forked
end 22 fits inside the hollow cylindrical shaft 36 of the second forked
end 24. _
For purposes of implantation between adjacent first and second
spinous processes of the spinal column, the implant 20 is configured
as shown in Fig. 2. The first and second spinous processes are
exposed using appropriate surgical techniques and thereafter, the
implant 20 is positioned so that saddle 26 engages the first spinous
process, and saddle 28 engages the second spinous process. At this
point, the interbody piece 30 can be rotated by placing an appropriate
tool or pin into the cross holes 40 and upon rotation, the saddle 26
is moved relative to the saddle 28. Such rotation spreads apart or
distracts the spinous processes with the resultant and beneficial effect.
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of enlarging the volume of the spinal canal in order to alleviate any
restrictions on blood vessels and nerves.
It is noted that this implant as well as the several other implants
described herein act as an extension stop. That means that as the
back is bent backwardly and thereby placed in extension the spacing
between adjacent spinous processes cannot be reduced to a distance
less than the distance between the lowest point of saddle 26 and the
lowest point of saddle 28. This implant, however, does not inhibit or
in any way limit the flexion of the spinal column, wherein the spinal
column is bent forward.
Preferably, such a device provides for distraction in the range of
about 5mm to about 15mm. However, devices which can distract up
to and above 22mm may be used depending on the characteristics of
the individual patient.
With all the ligaments (such as the superspinous ligament) and
tissues associated with the spinous processes left intact, the implant
can be implanted essentially floating in position in order to gain the
benefits of the aforementioned extension stop and flexion non-
inhibitor. If desired, one of the saddles 26 can be laterally pinned with
20 pin 29 to one of the spinous processes and the other saddle can be
loosely associated with the other spinous processes by using a tether
31 which either pierces or surrounds the other spinous process and
then is attached to the saddle in order to position the saddle relative
to the spinous process. Alternatively, both saddles can be loosely
tethered to the adjacent spinous process in order to allow the saddles
to move relative to the spinous processes.
The shape of the saddles, being concave, gives the advantage
of distributing the forces between the saddle and the respective
spinous process. This ensures that the bone is not resorbed due to the
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placement of the implant 20 and that the structural integrity of the
bone is maintained.
The implant 20 in this embodiment can be made of a number of
materials, including but not limited to, stainless steel, titanium,
ceramics, plastics, elastics, composite materials or any combination of
the above. In addition, the modulus of elasticity of the implant can be
matched to that of bone, so that the implant 20 is not too rigid. The
flexibility of the implant can further be enhanced by providing
additional apertures or perforations throughout the implant in addition
to the holes 40 which also have the above stated purpose of allowing
the interbody piece 30 to be rotated in order to expand the distance
between the saddle 26, 28.
In the present embodiment, it is understood that the spinous
processes can be accessed and distracted initially using appropriate
instrumentation, and that the implant 20 can be inserted and adjusted
in order to maintain and achieve the desired distraction. Alternatively,
the spinous process can be accessed and the implant 20 appropriately
positioned. Once positioned, the length of the implant can be adjusted
in order to distract the spinous processes or extend the distraction of
already distrc3cted spinous processes. Thus, the implant can be used
to create a distraction or to maintain a distraction which has already
been created.
The placement of implants such as implant 20 relative to the
spinous process will be discussed hereinbelow with other
embodiments. However, it is to be noted that ideally, the implant 20
would be placed close to the instantaneous axis of rotation of the
spinal column so that the forces placed on the implant 20 and the
forces that the implant 20 places on the spinal column are minimized.
Further, it is noted that during the actual process of installing or
implanting the implant 20, that the method uses the approach of
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extending the length of the implant 20 a first amount and then
allowing the spine to creep or adjust to this distraction. Thereafter,
implant 20 would be lengthened another amount, followed by a period
where the spine is allowed to creep or adjust to this new level of
distraction. This process could be repeated until the desired amount
of distraction has been accomplished. This same method can be used
with insertion tools prior to the installation of an implant. The tools
can be used to obtain the desired distraction using a series of spinal
distraction and spine creep periods before an implant is installed.
Embodiment of Figs. 6. 7. 8. 9 and 10
The embodiment of the invention shown in the above Figs. 6,
7, 8, 9 and 10 includes distraction or spreader tool 50 which has first
and second arms 52, 54. Arms 52, 54 are pivotal about pivot point
56 and releaseable from pivot point 56 in order to effect the
implantation of implant 58. As can be seen in Fig. 6, in cross-section,
the arms 52, 54 are somewhat concave in order to cradle and securely
hold the first spinous process 60 relative to arm 52 and the second
spinous process 62 relative to arm 54. The distraction tool 50 can be
inserted through a small incision in the back of the patient in order to
address the space between the first spinous process 60 and the
second spinous process 62. Once the tool 50 is appropriately
positioned, the arms 52, 54 can be spread apart in order to distract
the spinous processes. After this has occurred, an implant 58 as
shown in Figs. 8 and 9, or of a design shown in other of the
embodiments of this invention, can be urged between the arms 52, 54
and into position between the spinous processes. After this occurs,
the arms 52, 54 can be withdrawn from the spinous processes leaving
the implant 58 in place. The implant 58 is urged into place using a
tool 64 which can be secured to the implant 58 through a threaded
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bore 66 in the back of the implant. As can be seen in Fig. 10, the
implant 58 includes saddles 89 and 70 which cradle the upper and
lower spinous processes 60, 62 in much the same manner as the
above first embodiment and also in much the same manner as the
individual arms of the tool 50. The saddles as described above tend
to distribute the load between the implant and the spinous processes
and also assure that the spinous process is stably seated at the lowest
point of the respective saddles.
Embodiment of Fi:gs. 11. 12 and 13
Another embodiment of the apparatus and method of the
invention is shown in Figs. 11, 12 and 13. In this embodiment, the
spreader or distraction tool 80 includes first and second arms 82, 84
which are permanently pivoted at pivot point 86. The arms include L-
shaped ends 88, 90. Through a smali incision, the L-shaped ends 88,
90 can be inserted between the first and second spinous processes
92, 94. Once positioned, the arms 82, 84 can be spread apart in
order to distract the spinous processes. The implant 96 can then be
urged between the spinous processes in order to maintain the
distraction., It is noted that implant 96 includes wedged surfaces or
ramps 98, 100. As the implant 96 is being urged between the spinous
processes, the ramps further cause the spinous processes to be
distracted. Once the implant 96 is fully implanted, the full distraction
is maintained by the planar surfaces 99, 101 located rearwardly of the
ramps. It is to be understood that the cross-section of the implant 96
can be similar to that shown for implant 58 or similar to other implants
in order to gain the advantages of load distribution and stability.
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Embodiments of Figs. 14. 15. 16. 16a. and 17
In Figs. 14 and 15, yet another embodiment of the invention is
depicted. In this embodiment, the implant 110 includes first and
second conically shaped members 112, 114. Member 112 includes a
male snap connector 116 and member 114 includes a female snap
connector 118. With male snap connector 116 urged into female snap
connector 118, the first member 112 is locked to the second member
114. In this embodiment, a distraction or spreader tool 80 could be
used. Once the spinous process has been spread apart, an
implantation tool 120 can be used to position and snap together the
implant 110. The first member 112 of implant 110 is mounted on one
arm and second member 114 is mounted on the other arm of tool 120.
The member 112, 114 are placed on opposite sides of the space
between adjacent spinous processes. The members 112, 114 are
urged together so that the implant 110 is locked in place between the
spinous processes as shown in Fig. 15. It is to be noted that the
implant 110 can also be made more self-distracting by causing the
cylindrical surface 122 to be more conical, much as surface 124 is
conical, in order to hold implant 110 in place relative to the spinous
processes and also to create additional distraction.
An alternative embodiment of the implant can be seen in Figs.
16 and 17. This implant 130 includes first and second members 132,
134. In this particular embodiment, the implants are held together
using a screw (not shown) which is inserted through countersunk bore
136 and engages a threaded bore 138 of the second member 134.
Surfaces 139 are flattened (Fig. 17) in order to carry and spread the
load applied thereto by the spinous processes.
The embodiment of implant 130 is not circular in overall outside
appearance, as is the embodiment 110 of Figs. 14 and 15. In
particular, with respect to the embodiment of implant 130 of Figs. 16
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and 17, this embodiment is truncated so that the lateral side 140, 142
are flattened with the upper and lower sides 144, 146 being elongated
in order to capture and create a saddle for the upper and lower spinous
processes. The upper and lower sides, 144, 146 are rounded to
provide a more anatomical implant which is compatible with the
spinous processes.
If it is desired, and in order to assure that the first member 132
and the second member 134 are aligned, key 148 and keyway 150 are
designed to mate in a particular manner. Key 148 includes at least
one flattened surface, such as flattened surface 152, which mates to
an appropriately flattened surface 154 of the keyway 150. In this
manner, the first member is appropriately mated to the second member
in order to form appropriate upper and lower saddles holding the
implant 130 relative to the upper and lower spinous processes.
Fig. 16a depicts second member 134 in combination with a
rounded nose lead-in plug 135. Lead-in plug 135 includes a bore 137
which can fit snugly over key 148. In this configuration, the lead-in
plug 135 can be used to assist in the placement of the second member
134 between spinous processes. Once the second member 134 is
appropriately positioned, the lead-in plug 135 can be removed. It is to
be understood that the lead-in plug 135 can have other shapes such
as pyramids and cones to assist in urging apart the spinous processes
and soft tissues in order to position the second member 134.
Embodiment of Figs. 18. 19 and 20
The implant 330 as shown in Fig. 18 is comprised of first and
second mating wedges 332 and 334. In order to implant these
wedges 332, 334, the spinous processes are accessed from both sides
and then a tool is used to push the wedges towards each other. As
the wedges are urged towards each other, the wedges move relative
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to each other so that the combined dimension of the implant 330
located between the upper and lower spinous processes 336, 338
(Fig. 20), increases, thereby distracting the spinous processes. It is
noted that the wedges 332, 334 include saddle 340, 342, which
receiving the spinous processes 336, 338. These saddles have the
advantages as described hereinabove.
The first or second wedges 332, 334 have a mating
arrangement which includes a channel 344 and a projection of 346
which can be urged into the channel in order to lock the wedges 332,
334 together. The channel 334 is undercut in order to keep the
projection from separating therefrom . Further, as in other devices
described herein, a detent can be located in one of the channel and the
projection, with a complimentary recess in the other of the channel
and the projection. Once these two snap together, the wedges are
prevented from sliding relative to the other in the channel 344.
While the above embodiment was described with respect to
wedges, the wedges could also have been designed substantially as
cones with all the same features and advantages.
Embodiments of Figs. 21 and 22
The implant 370 is comprised of first and second distraction
cone 372, 374. These cones are made of a flexible material. The
cones are positioned on either side of the spinous processes 376, 378
as shown in Fig. 21. Using appropriate tool as shown hereinabove,
the distraction cones 372, 374 are urged together. As they are urged
together, the cones distract the spinous processes as shown in Fig.
22. Once this has occurred, an appropriate screw or other type of
fastening mechanism (not shown) can be used to maintain the position
of the distraction cones 372, 374. The advantage of this
arrangement is that
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the implant 370 is self-distracting and also that the implant, being
flexible, molds about the spinous processes as shown in Fig. 22.
Embodiments of Fig. 23. 24 and 25
In Figs. 23 and 24, another embodiment of the implant 170 is
depicted. This implant is guided in place using an L-shaped guide 172
which can have a concave cross-section such as the cross-section 52
of retraction tool 50 in Fig. 6 in order to cradle and guide the implant
170 in position. Preferably a small incision would be made into the
back of the patient and the L-shaped guide tool 172 inserted between
the adjacent spinous processes. The implant 170 would be mounted
on the end of insertion tool 174 and urged into position between the
spinous processes. The act of urging the implant into position could
cause the spinous processes to be further distracted if that is required.
Prior to the insertion of the L-shaped guide tool 172, a distraction tool
such as shown in Fig. 13 could be used to initially distract the spinous
processes.
Implant 170 can be made of a deformable material so that it can
be urged into place and so that it can somewhat conform to the shape
of the upper and lower spinous processes. This deformable material
would be preferably an elastic material. The advantage of such a
material would be that the load forces between the implant and the
spinous processes would be distributed over a much broader surface
area. Further, the implant would mold itself to an irregular spinous
process shape in order to locate the implant relative to spinous
processes.
With respect to Fig. 25, this implant 176 can be inserted over
a guide wire, guide tool or stylet 178. Initially, the guide wire 178 is
positioned through a small incision to the back of the patient to a
position between the adjacent spinous processes. After this has
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occurred, the implant is threaded over the guide wire 178 and urged
into position between the spinous processes. This urging can further
distract the spinous processes if further distraction is required. Once
the implant is in place, the guide tool 178 is removed and the incision
closed. The insertion tools of Figs. 23 and 24 can also be used if
desired.
Embodiment of Figs. 26. 27 and 28
The embodiment shown in Figs. 26, 27 and 28 uses an implant
similar to that depicted in Figs. 8 and 9 with diffefrent insertion tools.
As can be seen in Fig. 26, an L-shaped distraction tool 190 is similar
to L-shaped distraction tool 80 (Fig. 12), is used to distract the first
and second spinous processes 192, 194. After this has occurred, an
insertion tool 196 is placed between the spinous processes 192, 194.
Insertion tool 196 includes a handle 198 to which is mounted a
square-shaped ring 200.
The distraction tool 190 can be inserted through a small incision
in the back in order to spread apart the spinous processes. Through
the same incision which has been slightly enlarged laterally, an upper
end 202 of ring 200 can be initially inserted followed by the remainder
of the ring 200. Once the ring is inserted, the ring can be rotated
slightly by moving handle 198 downwardly in order to further wedge
the spinous processes apart. Once this has been accomplished, an
implant such as implant 204 can be inserted through the ring and
properly positioned using implant handle 206. Thereafter, the implant
handle 206 and the insertion tool 196 can be removed.
Embodiments of Figs. 29. 30. 31. 32 and 33
As can be seen in Figs. 29 and 30, the implants 210, 212, can
have different shapes when viewed from the side. These implants are
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similar to the above-referenced implants 58 (Fig. 8) and 204 (Fig. 28).
These implants have cross-sections similar to that shown in Fig. 10
which includes saddles in order to receive and hold the adjacent
spinous processes.
As can be seen in Figs. 31, 32 and 33, these implants can be
placed in different positions with respect to the spinous process 214.
Preferably as shown in Fig. 33, the implant 210 is placed closest to
the lamina 216. Being so positioned, the implant 210 is close to the
instantaneous axis of rotation 218 of the spinal column, and the
implant would experience least forces caused by-movement of the
spine. Thus, theoretically, this is the optimal location for the implant.
As can be seen in Figs. 31 and 32, the implant can be placed
midway along the spinous process (Fig. 32) and towards the posterior
aspect of the spinous process (Fig. 31). As positioned shown in Fig.
31, the greatest force would be placed on the implant 210 due to a
combination of compression and extension of the spinal column.
Embodiment of Figs. 34 and 35
Another embodiment of the invention is shown in Figs. 34 and
35. In these figures, implant 220 is comprised of a plurality of
individual leaves 222 which are substantially V-shaped. The leaves
include interlocking indentations or detents 224. That is, each leaf
includes an indentation with a corresponding protrusion such that a
protrusion of one leaf mates with an indentation of an adjacent leaf.
Also associated with this embodiment is an insertion tool 226 which
has a blunt end 228 which conforms to the shape of an individual leaf
222. For insertion of this implant into the space between the spinous
processes as shown in Fig. 29, the insertion tool 226 first insert a
single leaf 220. After that has occurred, the insertion tool then inserts
a second leaf with the protrusion 224 of the second leaf snapping into
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corresponding indentation made by the protrusion 224 of the first leaf.
This process would reoccur with third and subsequent leaves until the
appropriate spacing between the spinous processes was built up. As
can be seen in Fig. 29, the lateral edges 229 of the individual leaves
222 are slightly curved upwardly in order to form a saddle for receiving
the upper and lower spinous processes.
Embodiments of Figs. 36. 37 and 38
= The embodiments of Figs. 36, 37 and 38 which include implants
230, 232, and 234 respectively, are designed in such a manner so the
implant locks itself into position once it is properly positioned between
the spinous processes. Implant 230 is essentially a series of truncated
cones and includes a plurality of ever expanding steps 236. These
steps are formed by the conical bodies starting with the nose body
i5 238 followed there behind by conical body 240. Essentially, the
implant 230 looks like a fir tree placed on its side.
The implant 230 is inserted laterally throughout the opening
between upper and lower spinous processes. The first body 238
causes the initial distraction. Each successive conical body distracts
the spinous processes a further incremental amount. When the
desired distraction has been reached, the spinous processes are locked
into position by steps 236. At this point, if desired, the initial nose
body 238 of the implant and other bodies 240 can be broken, snapped
or sawed off if desired in order to minimize the size of the implant 230.
In order for a portion of the implant 230 to be broken or snapped off,
the intersection between bodies such as body 238 and 240, which is
intersection line 242, wou0d be somewhat weaken with the appropriate
removal of material. It is noted that only the intersection lines of the
initial conical bodies need to be so weakened. Thus, intersection line
244 between the bodies which remain between the spinous processes
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would not need to be weaker, as there would be no intention that the
implant would be broken off at this point.
Fig. 37 shows implant 232 positioned between upper and lower
spinous processes. This implant is wedge-shaped or triangular shaped
in cross-sectioned and includes bore pluralities 245 and 246. Through
these bores can be placed locking pins 248 and 250. The triangular
or wedged-shaped implant can be urged laterally between and thus
distract the upper and lower spinous processes. Once the appropriate
distraction is reached, pins 248, 250 can be inserted through the
appropriate bores of the bore pluralities 245 and 246 in order to lock
the spinous processes in a V-shaped valley formed by pins 248, 250
on the one hand and the ramped surface 233, 235 on the other hand.
Turning to Fig. 38, the implant 234 has a triangular-shaped or
wedge-shaped body similar to that shown in Fig. 32. In this
embodiment, tab 252, 254 are pivotally mounted to the triangular
shaped body 234. Once the implant 234 is appropriately positioned
in order to distract the spinous processes to the desired amount, the
tabs 252, 254 rotate into position in order to hold the implant 234 in
the appropriate position.
Embodiment of Figs. 39 and 40
In the embodiment of Figs. 39 and 40, cannula 258 is inserted
through a small incision to a position between upper and lower spinous
processes. Once the cannula is properly inserted, an implant 260 is
pushed through the cannula 258 using an insertion tool 262. The
implant 260 includes a plurality of ribs or indentation 264 that assist
in positioning the implant 260 relative to the upper and lower spinal
processes. 'Once the implant 260 is in position, the cannula 258 is
withdrawn so that the implant 260 comes in contact with and wedges
between the spinous processes. The cannula 258 is somewhat conical
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in shape with the nose end 266 being somewhat smaller than the
distal end 268 in order to effect the insertion of the cannula into the
space between the spinous processes.
Further, a plurality of cannula can be used instead of one, with
each cannula being slightly bigger than one before. In the method of
the invention, the first smaller cannula would be inserted followed by
successively larger cannula being placed over the previous smaller
cannula. The smaller cannula would then be withdrawn from the
center of the larger cannula. Once the largest cannula is in place, and
the opening of the skin accordingly expanded, thff implant, which is
accommodated by only the larger cannula, is inserted through the
larger cannula and into position.
Embodiments of Figs,41. 42 and 43
The precurved implant 270 in Figs. 41 and 42, and precurved
implant 272 in Fig. 43 have common introduction techniques which
includes a guide wire, guide tool, or stylet 274. For both
embodiments, the guide wire 274 is appropriately positioned through
the skin of the patient and into the space between the spinous
processes. After this is accomplished, the implant is directed over the
guide wire and into position between the spinous processes. The
precurved nature of the implant assist in (1) positioning the implant
through a first small incision in the patient's skin on one side of the
space between two spinous processes and (2) guiding the implant
toward a second small incision in the patient's skin on the other side
of the space between the two spinous processes. With respect to the
implant 270, the implant includes a conical introduction nose 276 and
a distal portion 278. As the nose 276 is inserted between the spinous
processes, this causes distraction of the spinous processes. Break
lines 280, 282 are established at opposite sides of the implant 270.
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Once the implant is properly positioned over the guide wire between
the spinous processes, the nose portion 276 and the distal portion 278
can be broken off along the break lines, through the above two
incisions, in order to leave the implant 270 in position.
Although only two break lines 280, 282 are depicted, multiple
break lines can be provided on implant 270 so that the implant can
continue to be fed over the guide wire 274 until the appropriate width
of the implant 270 creates the desired amount of distraction. As
described hereinabove, the break lines can be created by perforating
or otherwise weakening the implant 270 so th-at the appropriate
portions can be snapped or sawed off.
With respect to the precurved implant 272, this implant is similar
in design to the implant 230 shown in Fig. 36. This implant 272 in
Fig. 47, however, is precurved and inserted over a guide wire 274 to
a position between the spinous processes. As with implant 230 in Fig.
43, once the appropriate level of this distraction has been reached and
if desired, sections of the implant 272 can be broken, snapped or
sawed off as described hereinabove in order to leave a portion of the
implant wedged between the upper and lower spinous processes.
Embodiment of Fig. 44
A further embodiment of the invention is shown in Fig. 44. This
embodiment includes a combination insertion tool and implant 290.
The insertion tool and implant 290 is in the shape of a ring which is
hinged at point 292. The ring is formed by a first elongated and
conically shaped member 294 and a second elongated and conically
shaped member 296. Members 294 and 296 terminate in points and
through the use of hinge 292 are aligned and meet. Through similar
incisions on both sides of the spinous processes, first member and
second member are inserted through the skins of the patient and are
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mated together between the spinous processes. After this has
occurred, the implant 290 is rotated, for example clockwise, so that
increasingly widening portions 293 of the first member 294 are used to
distract the first and second spinous processes. When the appropriate
level of distraction has occurred, the remainder of the ring before and
after the section which is located between the spinous processes can
be broken off as taught hereinabove in order to maintain the desired
distraction. Alternatively, with a small enough ring, the entire ring can
be left in place with the spinous processes distracted.
-
Embodiment of Fig. 45
In Fig. 45, the implant 300 is comprised of a plurality of rods or
stylets 302 which are inserted between the upper and lower spinous
processes. The rods are designed much as described hereinabove so
that they may be broken, snapped or cut off. Once these are inserted
and the appropriate distraction has been reached, the stylets are
broken off and a segment of each stylet remains in order to maintain
distraction of the spinous process.
Embodiment of Figs. 46 and 47
Implant 310 of Figs. 46 and 47 is comprised of a shape memory
material which coils upon being released. The material is straightened
out in a delivery tool 312. The delivery tool is in position between
upper arid lower spinous processes 314, 316. The material is then
pushed through the delivery tool. As it is released from the delivery
end 318 of the delivery tool, the material coils, distracting the spinous
processes to the desired amount. Once this distraction has been
achieved, the material is cut and the defivery tool removed.
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Embodiments of Figs. 48. 49. 50 and 51
As can be seen in Fig. 48, the implant 320 is delivered between
upper and lower spinous processes 322 and 324, by delivery tool 326.
Once the implant 320 is in place between the spinous processes, the
delivery tool is given a 90 twist so that the implant goes from the
orientation as shown in Fig. 49, with longest dimension substantially
perpendicular to the spinous processes, to the orientation shown in
Fig. 50 where the longest dimension is in line with and parallel to the
spinous processes. This rotation causes the desired distraction
between the spinous processes. Implant 320-includes opposed
recesses 325 and. 323 located at the ends thereof. Rotation of the
implant 320 causes the spinous processes to become lodged in these
recesses.
Alternatively, the insertion tool 326 can be used to insert
multiple implants 320, 321 into the space between the spinous
processes 322, 324 (Fig. 51). Multiple implants 320, 321 can be
inserted until the appropriate amount of distraction is built up. It is to
be understood in this situation that one implant would lock to another
implant by use of, for example, a channel arrangement wherein a
projection from one of the implants would be received into and locked
into a channel of the other implant. Such a channel arrangement is
depicted with respect to the other embodiment.
Embodiment of Figs. 52. 53. 54. 55a and 55b
The embodiment of Figs. 52 through 55b is comprised of a fiuid-
filled dynamic distraction implant 350. This implant includes a
membrane 352 which is placed over pre-bent insertion rod 354 and
then inserted through an incision on one side of the spinous process
356. The bent insertion rod, with the implant 350 thereover, is guided
between appropriate spinous processes. After this occurs, the
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insertion rod 354 is removed leaving the flexible implant in place. The
implant 350 is then connected to a source of fluid (gas, liquid, gel and
the like) and the fluid is forced into the implant causing it to expand as
shown in Fig. 54, distracting the spinal processes to the desired
amount. Once the desired amount of distraction has occurred, the
implant 350 is closed off as is shown in Fig. 55a. The implant 350
being flexible, can mold to the spinous processes which may be of
irregular shape, thus assuring positioning. Further, implant 350 acts
as a shock absorber, damping forces and stresses between the implant
and the spinous processes. -
A variety of materials can be used to make the implant and the
fluid which is forced into the implant. By way of example only,
viscoelastic substances such as methylcellulose, or hyaluronic acid can
be used to fill the implant. Further, materials which are initially a fluid,
but later solidify, can be inserted in order to cause the necessary
distraction. As the materials solidify, they moid into a custom shape
about the spinous processes and accordingly are held in position at
least with respect to one of two adjacent spinous processes. Thus, it
can be appreciated that using this embodiment and appropriate
insertion tools the implant can be formed about one spinous process
in such a manner that the implant stays positioned with respect to that
spinous process (Fig. 55b). With such an embodiment, a single
implant can be used as an extension stop for spinous process located
on either side, without restricting flexion of the spinal column.
It is to be understood that many of the other implants disclosed
herein can be modified so that they receive a fluid in order to establish
and maintain a desired distraction much in the manner as implant 350
receives a fluid.
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Embodiment of Figs. 56. 57 and 58
The implant 360 as shown in Fig. 56 is comprised of a shape
memory material such as a plastic or a metal. A curved introductory
tool 362 is positioned between the appropriate spinous processes as
described hereinabove. Once this has occurred, bore 364 of the
implant is received over the tool. This act can cause the implant to
straighten out. The implant is then urged into position and thereby
distracts the spinous processes. When this has occurred, the insertion
tool 362 is removed, allowing the implant to assume its pre-
straightened configuration and is thereby secured' about one of the
spinous processes. Such an arrangement allows for an implant that is
an extension stop and does not inhibit flexion of the spinous column.
Alternatively, the implant can be temperature sensitive. That is to say
that the implant would be more straightened initially, but become more
curved when it was warmed by the temperature of the patient's body.
Embodiments of Figs. 59 and 60
In this embodiment, the implant 380 is comprised of a plurality
of interlocking leaves 382. Initially, a first leaf is positioned between
opposed spinous processes 384, 386. Then subsequently, leafs 382
are interposed between the spinous processes until the desired
distraction has been built up. The leaves are somewhat spring-like in
order to absorb the shock and can somewhat conform to the spinous
processes.
Embodiment of Fia. 61
The implant 390 of Fig. 61 includes the placement of shields
392, 394 over adjacent spinous processes 396, 398. The shields are
used to prevent damage to the spinous processes. These shields
include apertures which receives a self-tapping screw 400, 402. In
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practice, the shields are affixed to the spinous processes and the
spinous processes are distracted in the appropriate amount. Once this
has occurred, a rod 404 is used to hold the distracted position by
being screwed into each of the spinous processes through the aperture
in the shields using the screws as depicted in Fig. 61.
Embodiment of Figs. 62 and 63
Implant 410 of Figs. 62, 63 is comprised of first and second
members 412, 414 which can be mated together using an appropriate
screw and threaded bore arrangement to form the irnplant 410. Main
member 412 and mating member 414 form implant 410. Accordingly,
the implant 410 would have a plurality of members 414 for use with
a standardized first member 412. Figs. 62 and 64 show different
types of mating members 414. In Fig. 62, the mating member 414
includes projections 416 and 418 which act like shims. These
projections are used to project into the space of saddles 420, 422 of
the first member 412. These projections 416, 418 can be of varying
lengths in order to accommodate different sizes of spinous processes.
A groove 424 is placed between the projections 416, 418 and mates
with an extension 426 of the first member 412.
As shown in Fig. 63, the projections of the embodiment shown
in Fig. 62 are removed and recesses 428, 430 are substituted therefor.
These recesses expand the area of the saddles 420, 422 in order to
accommodate larger spinous processes.
Embodiment of Fjgs. 64. 65 and 66
The embodiments of Figs. 64, 65 and 66 are similar in design
and concept to the embodiment of Figs. 62 and 63. In Fig. 64, the
implant 500 includes the first and second members 502, 504. These
members can be secured together with appropriate screws or other
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fastening means as taught in other embodiments. Implant 500
includes first and second saddles 506, 508 which are formed between
the ends of first and second members 502, 504. These saddles 506,
508 are used to receive and cradle the adjacent spinous processes.
As can be seen in Fig. 64, each saddle 506, 508 is defined by a single
projection or leg 510, 512, which extends from the appropriate first
and second members 502, 504. Unlike the embodiment found in Figs.
62 and 63, each of the saddles is defined by only a single leg as the
ligaments and other tissues associated with the spinous processes can
be used to ensure that the implant is held in an ap'propriate position.
With the configuration of Fig. 64, it is easier to position the implant
relative to the spinous processes as each saddle is defined by only a
single leg and thus the first and second members can be more easily
worked into position between the various tissues.
In the embodiment of Fig. 65, the implant 520 is comprised of
a single piece having saddles 522 and 524. The saddles are defined
by a single leg 526, 528 respectively. In order for this implant 520 to
be positioned between the spinous processes, an incision is made
between lateral sides of adjacent spinous processes. The single leg
526 is directed through the incision to a position adjacent to an
opposite lateral side of the spinous process with the spinous process
cradled in the saddle 522. The spinous processes are then urged apart
until saddle 524 can be pivoted into position into engagement with the
other spinous process in order to maintain the distraction between the
two adjacent spinous processes.
The embodiment of Fig. 66 is similar to that of Fig. 65 with an
implant 530 and first and second saddles 532 and 534. Associated
with each saddie is a tether 536, 538 respectively. The tethers are
made of flexible materials known in the trade and industry and are
positioned through bores in the implant 530. Once appropriately
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positioned, the tethers can be tied off. It is to be understood that the
tethers are not meant to be used to immobilize one spinous process
relative to the other, but are used to guide motion of the spinous
processes relative to each other so that the implant 530 can be used
as an extension stop and a flexion non-inhibitor. In other words, the
saddles 532, 534 are used to stop spinal column backward bending
and extension. However, the tethers do not inhibit forward bending
and spinal column flexion.
Embodiments of Figs. 67. 68
T he implant 550 is Z-shaped and includes a central body 552
and first and second arms 554, 556, extending in opposite directions
therefrom. The central body 552 of the implant 550 includes first and
second saddles 558 and 560. The first and second saddles 558 and
560 would receive upper and lower spinous processes 562, 568. The
arms 554, 556 are accordingly located adjacent the distal end 566
(Fig. 68) of the central body 552. The first and second arms 554,
556, act to inhibit forward movement, migration or slippage of the
implant 550 toward the spinal canal and keep the implant in place
relative to the first and second spinal processes. This prevents the
implant from pressing down on the ligamentum flavum and the dura.
In a preferred embodiment, the central body would have a height of
about 10mm with each of the arms 554, 556 have a height of also
about 10mm. Depending on the patient, the height of the body could
vary from about less than 10mm to about greater than 24mm. As can
be seen in Figs. 67 and 68, the first and second arms 554, 556 are
additionally contoured in order to accept the upper and lower spinous
processes 562, 568 . In particular, the arms 554, 556 as can be seen
with respect to arm 554 have a slightly outwardly bowed portion 568
(Fig. 68) with a distal end 570 which is slightly inwardly bowed. This
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configuration allows the arm to fit about the spinous process with the
distal end 570 somewhat urged against the spinous process in order
to guide the motion of the spinous process relative to the implant.
These arms 554, 556 could if desired to be made more flexible than
the central body 552 by making arms 554, 556 thin and/or with
perforations, and/or other material different than that of the central
body 552 . As with the last embodiment, this embodiment can be
urged into position between adjacent spinous processes by directing
an arm into a lateral incision so that the central body 552 can be
finally positioned between spinous processes. ~
Embodiment of Figs. 69. 70. 71 and 71 a
Figs. 69, 70 and 71 are perspective front, end, and side views
of implant 580 of the invention. This implant includes a central body
582 which has first and second saddles 584, 586 for receiving
adjacent spinous processes. Additionally, the implant 580 includes
first and second arms 588 and 590. The arms, as with the past
embodiment, prevent forward migration or slippage of the implant
toward the spinal canal. First arm 588 projects outwardly from the
first saddle 584 and second arm 590 projects outwardly from the
second saddle 586. In a preferred embodiment, the first arm 588 is
located adjacent to the distal end 600 of the central body 582 and
proceeds only partly along the length of the central body 582. The
first arm 588 is substantially perpendicular to the central body as
shown in Fig. 70. Further, the first arm 588, as well as the second
arm 590, is anatomically rounded.
The second arm 590, projecting from second saddle 586, is
located somewhat rearward of the distal end 600, and extends
partially along the length of the central body 582. The second arm
3 0 590 projects at a compound angle from tl -le central body 582. As can
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be seen in Figs. 70 and 71, the second arm 590 is shown to be at
about an angle of 45 from the saddle 586 (Fig. 70). Additionally, the
second arm 590 is at an angle of about 45 relative to the length of
the central body 582 as shown in Fig. 71. It is to be understood that
other compound angles are within the spirit and scope of the invention
as claimed.
In a preferred embodiment, the first and second arms 588, 590
have a length which is about the same as the width of the central
body 582. Preferably, the length of each arm is about 10mm and the
width of the central body is about 10mm. However, the bodies with
the widths of 24mm and greater are within the spirit and scope of the
invention, along with first and second arms ranging from about 10mm
to greater than about 24mm. Further, it is contemplated that the
embodiment could include a central body having a width of about or
greater than 24mm with arms being at about 10mm.
It is to be understood that the embodiment of Figs. 69, 70 and
71 as well as the embodiment of Figs. 67 and 68 are designed to
preferably be positioned between the L4-L5 and the L5-S1 vertebral
pairs. The embodiment of Figs. 69, 70, 71 is particularly designed for
the L5-S1 position with the arms being designed to conform to the
sloping surfaces found therebetween. The first and second arms are
thus contoured so that they lie flat against the lamina of the vertebra
which has a slight angle.
The embodiment of Fig. 69, 70, and 71 as with the embodiment
of Figs. 67 and 68 is Z-shaped in configuration so that it may be
inserted from one lateral side to a position between adjacent spinous
processes. A first arm, followed by the central body, is guided
through the space between the spinous processes. Such an
arrangement only requires that a incision on one side of the spinous
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process be made in order to successfully implant the device between
the two spinous processes.
The implant 610 of Fig. 71 a is similar to that immediately above
with the first arm 612 located on the same side of the implant as the
second arm 614. The first and second saddle 616, 618 are slightly
modified in that distal portion 620, 622 are somewhat flattened from
the normal saddle shape in order to allow the implant to be positioned
between the spinous processes from one side. Once in position, the
ligaments and tissues associated with the spinous processes would
hold the implant into position. Tethers also could te used if desired.
Embodiment of Figs. 72. 73
Implant 630 is also designed so that it can be inserted from one
side of adjacent spinous processes. This implant 630 includes a central
body 632 with the first and second arms 634, 636 extending on either
side thereof. As can be seen in Fig. 72, a plunger 638 is positioned
to extend from an end of the central body 632. As shown in Fig. 72,
the plunger 638 is fully extended and as shown in Fig. 73, the plunger
638 is received within the central body 632 of the implant 630. With
the plunger 638 received into the implant 630, the third and fourth arms or
hooks 640, 642 can extend outwardly from the central body 632. The
third and fourth arms or hooks 640, 642 can be comprised of a variety
of materials, such as for example, shape memory metal materials or
materials which have a springy quality.
For purposes of positioning the implant 630 between adjacent
spinous processes, the plunger 638 is pulled outwardly as shown in
Fig. 72. The central body 632 is then positioned between adjacent
spinous processes and the plunger 638 is allowed to move to the
position of Fig. 73 so that the third and fourth arms 640, 642 can
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project outwardly from the central body 632 in order to hold the
implant 630 in position between the spinous processes.
Plunger 638 can be spring biased to the position as shown in
Fig. 73 or can include detents or other mechanisms which lock it into
that position. Further, the third and fourth arms themselves, as
deployed, can keep the plunger in the position as shown in Fig. 73.
Embodiments of Figs. 74. 75. 76, 77, and 78
Other embodiments of the invention are shown in Figs. 74
through 78. Figs. 74, 75 and 76 disclose implant-700. Implant 700
is particularly suited for implantation between the L4-L5 and L5-S1
vertebra. As can be seen in Fig. 74, the implant 700 includes a central
body 702 which has a bore 704 provided therein. Bore 704 is used
in order to adjust the modulus of elasticity of the implant so that it is
preferably approximately two times the anatomical load placed on the
vertebra in extension. In other words, the implant 700 is
approximately two times stiffer than the normal load placed on the
implant. Such an arrangement is made in order to ensure that the
implant is somewhat flexible in order to reduce potential resorption of
the bone adjacent to the implant. Other modulus values can be used
and be within the spirit of the invention.
Implant 700 includes first and second saddle 706, 708 which
are used to receive and spread the load from the upper and lower
spinous processes. The saddle 706 is defined by first and second
arms 710 and 712. The second saddle 708 is defined by third and
fourth arms 714 and 716. As can be seen in Fig. 74, the first arm
710, in a preferred embodiment, is approximately two times the length
of the body 702 with the second arm being approximately less than a
quarter length of the body. Third arm 714 is approximately one times
the length of the body 702 with the fourth arm 716 being, in this
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preferred embodiment, approximately one and a half times the length
of the body 702. The arms are designed in such a way that the
implant (1) can be easily and conveniently inserted between the
adjacent spinous processes, (2) will not migrate forwardly toward the
spinal canal, and (3) will hold its position through flexion and extension
as well as lateral bending of the spinal column.
First arm 710 is in addition designed to accommodate the shape
of the vertebra. As can be seen in Fig. 74, the first arm 710 becomes
narrower as it extends away from the body 702. The first arm 710
includes a sloping portion 718 followed by a small recess 720 ending
in a rounded portion 722 adjacent to the end 724. This design is
provided to accommodate the anatomical form of for example the L4
vertebra. It is to be understood that these vertebra have a number of
surfaces at roughly 30 angles and that the sloping surfaces of this
embodiment and the embodiments shown in Figs. 77 and 78 are
designed to accommodate these surfaces. These embodiments can be
further modified in order to accommodate other angles and shapes.
The second arm 712 is small so that it is easy to insert between
the spinous processes, yet still define the saddle 706. The fourth arm
716 is larger than the third arm 714, both of which are smaller than
the first arm 710. The third and fourth arms are designed so that they
define the saddle 706, guide the spinous processes relative to the
implant 700 during movement of the spinal column, and yet are of a
size which makes the implant easy to position between the spinous
processes.
The procedure, by way of example only, for implanting the
implant 700 can be to make an incision laterally between two spinous
processes and then initially insert first arm 710 between the spinous
processes. The implant and/or appropriate tools would be used to
distract the spinous processes allowing the third leg 714 and the
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central body 702 to fit through the space between the spinous
processes. The third leg 714 would then come to rest adjacent the
lower spinous processes on the opposite side with the spinous
processes resting in the first and second saddle 706, 708. The longer
fourth leg 716 would then assist in the positioning of the implant 700.
Fig. 77 includes an implant 740 which is similar to implant 700
and thus have similar numbering. The saddle 706, 708 of implant 740
have been cantered or sloped in order to accommodate the bone
structure between, by way of example, the L4-L5 and the L5-S1
vertebra. As indicated above, the vertebra in this area have a number
of sloping surfaces in the range of about 30 . Accordingly, saddle
706 is sloped at less than 30 and preferably about 20 while saddle
708 is sloped at about 30 and preferably more than 30 .
The implant 760 as shown in Fig. 78 is similar to implant 700
in Fig. 74 and is similarly numbered. Implant 760 includes third and
fourth legs 714, 716 which have sloping portions 762, 764 which
slope toward ends 766, 768 of third and fourth arm 714, 716
respectively. The sloping portions accommodate the form of the lower
vertebra against which they are positioned. In the preferred
embodiment, the sloping portions are of about 30 . However, it is to
be understood that sloping portions which are substantially greater and
substantially less than 30 can be included and be within the spirit and
scope of the invention.
Embodiment of Fig. 79. 80. 80a. 81. 82. 83. 83a. 84.
85. 86 and 87
Another embodiment of the invention is shown in Figs. 79-87
and includes implant 800a (Fig. 86). Implant 800a includes a distracting
unit 802a which is shown in ieft side, plan, and right side views of Figs.
79, 80 and 81. A perspective view of the distraction unit is shown in
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Fig. 84. The distracting unit 802a as can be seen in Fig. 80 includes a
distracting body 804, with longitudinal axis 805, which body 804 has
a groove 806 and a rounded or bulbous end 808 which assist in the
placement of the distracting body 804 between adjacent spinous process
so that an appropriate amount of distraction can be accomplished.
Extending from the distracting body 804 is a first wing 810 which in
Fig. 80 is substantially perpendicular to the distracting body 804.
Such wings which are not perpendicular to the distracting body 804 are within
the
spirit and scope of the invention. First wing 810 includes a upper
portion 812 and a lower portion 814. The upper portion 812 (Fig.
80) includes a rounded end 816 and a small recess 818. The rounded
end 816 and the small recess 818 in the preferred embodiment are
designed to accommodate the anatomical form or contour of the L4
(for a L4-L5 placement) or L5 (for a L5-S1 placement) superior lamina
of the vertebra. It is to be understood that the same shape or
variations of this shape can be used to accommodate other lamina of
any vertebra. The lower portion 814 is also rounded in order to
accommodate in the preferred embodiment in order to accommodate
the vertebrae. The distracting unit 802a further includes a threaded bore
820 which in this embodiment accepts a set screw 822 (Fig. 86) in
order to hold a second wing 824 (Figs. 82, 83) in position as will be
discussed hereinbelow.
The threaded bore 820 in this embodiment slopes at
approximately 45 angle and intersects the slot 806. With the second
wing 824 in position, the set screw 822 when it is positioned in the
threaded bore 820 can engage and hold the second wing 824 in
position in the slot 806.
Turning to Figs. 82, 83 and 85, left side, plan and perspective
views of the second wing 824 are depicted. The second wing 824 is
similar in design to the first wing. The second wing includes an upper
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portion 826 and a lower portion 828. The upper portion includes a
rounded end 830 and a small recess 832. In addition, the second
wing 824 includes a slot 834 which mates with the slot 806 of the
distracting unit 802. The second wing 824 is the retaining unit of the
present embodiment.
As can be seen in Fig. 83 and 86, the second wing or retaining
unit 824 includes the upper portion 826 having a first width "a" and
the lower portion 828 having a second width "b". In the preferred
embodiment, the second width "b" is larger than first width "a" due to
the anatomical form or contour of the L4-L5 or L5-S1 laminae. As can
be seen in Fig. 83a in second wing or retaining unit 824, the widths
"a" and "b" would be increased in order to, as described hereinbelow,
accommodate spinous processes and other anatomical forms or
contours which are of different dimensions. Further, as appropriate,
width "a" can be larger than width "b". Thus, as will be described
more fully hereinbelow, the implant can include a universally-shaped
distracting unit 802 with a plurality of retaining units 824, with each
of the retaining units having different widths "a" and "b". During
surgery, the appropriately sized retaining unit 824, width with the
appropriate dimensions "a" and "b" can be selected to match to the
anatomical form of the patient.
Fig. 86 depicts an assembled implant 800 positioned adjacent
to upper and lower laminae 836, 838 (which are shown in dotted lines)
of the upper and lower vertebrae. The vertebrae 836, 838 are
essentially below the implant 800 as shown in Fig. 86. Extending
upwardly from the vertebrae 836, 838, and between the first and
second wings 810, 824, are the upper and lower spinous processes
840, 842. It is to be understood that in a preferred embodiment, the
fit of the implant between the spinous processes can be such that the
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wings do not touch the spinous processes, as shown in Fig. 86, and
be within the spirit and scope of the invention.
The implant 800 includes, as assembled, an upper saddle 844
and the lower saddle 846. The upper saddle 844 has an upper width
identified by the dimension "UW". The lower saddle 846 has a lower
width identified by the dimension "LW". In a preferred embodiment,
the upper width is greater than the lower width. In other
embodiments, the "UW" can be smaller than the "LW" depending on
the anatomical requirements. The height between the upper and lower
saddles 844, 846 is identified by the letter "h". These dimensions are
carried over into Fig. 87 which is a schematic representation of the
substantially trapezoidal shape which is formed between the upper and
lower saddles. The table below gives sets of dimensions for the upper
width, lower width, and height as shown in Fig. 87. This table
includes dimensions for some variations of this embodiment.
TABLE
Variation 1 2 3
Upper Width 8 7 6
Lower Width 7 6 5
Height 10 9 8
For the above table, all dimensions are given in millimeters.
For purposes of surgical implantation of the implant 800 into a
patient, the patient is preferably positioned on his side (arrow 841
points up from an operating table) and placed in a flexed (tucked)
position in order to distract the upper and lower vertebrae.
In a preferred procedure, a small incision is made on the midline
of the spinous processes. The spinous processes are spread apart or
distracted with a spreader. The incision is spread downwardly toward
the table, and the distracting unit 802 is preferably inserted upwardly
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between the spinous processes 840 and 842 in a manner that
maintains the distraction of spinous processes. The distracting unit
802 is urged upwardiy until the distracting or bulbous end 808 and the
slot 806 are visible on the other wide of the spinous process. Once
this is visible, the incision is spread upwardly away from the table and
the retaining unit or second wing 824 is inserted into the slot 806 and
the screw 822 is used to secure the second wing in position. After
this had occurred, the incisions can be closed.
An alternative surgical approach requires that small incisions be
made on either side of the space located between the spinous
processes. The spinous processes are spread apart or distracted using
a spreader placed through the upper incision. From the lower incision,
the distracting unit 802 is preferably inserted upwardly between the
spinous processes 840 and 842 in a manner that urges the spinous
processes apart. The distracting unit 802 is urged upwardly until the
distracting or bulbous end 808 and the slot 806 are visible through the
second small incision in the patient's back. Once this is visible, the
retaining unit or second wing 824 is inserted into the slot 806 and the
screw 822 is used to secure the second wing in position. After this
has occurred, the incisions can be closed.
The advantage of either of the above present surgical
procedures is that a surgeon is able to observe the entire operation,
where he can look directly down onto the spinous processes as
opposed to having to view the procedure from positions which are to
the right and to the left of the spinous processes. Generally, the
incision is as small as possible and the surgeon is working in a bloody
and slippery environment. Thus, an implant that can be positioned
directly in front of a surgeon is easier to insert and assemble than an
implant which requires the surgeon to shift from side to side.
Accordingly, a top-down approach, as an approach along a position to
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anterior line is preferred so that all aspects of the implantation
procedure are fully visible to the surgeon at all times. This aides in the
efficient location of (i) the distracting unit between the spinous
processes, (ii) the retaining unit in the distracting unit, and (iii) finally
the set screw in the distracting unit.
Fig. 80a shows an alternative embodiment of the distracting unit
802a. This distracting unit 802a is similar to distracting unit 802 in
Fig. 80 with the exception that the bulbous end 808a is removable
from the rest of the distracting body 804a as it is screwed into the
threaded bore 809. The bulbous end 808a is_removed once the.
distracting unit 802a is positioned in the patient in accordance with the
description associated with Fig. 86. The bulbous end 808a can extend
past the threaded bore 820 by about 1 cm in a preferred embodiment.
Embodiment of Figs. 88. 89. 90 and 91
Another embodiment of the invention is shown in Figs. 88, 89,
90 and 91. In this embodiment, the implant is identified by the
number 900. Other elements of implant 900 which are similar to
implant 800 are similarly numbered but in the 900 series (for
example elements 910, 912, 914, and 916 of the first w(ing correspond to
elements
810, 812, 814, and 816 of the previous embodiment, and elements 930 and 932 of
the second wing correspond to elernenis 830 and 832 of the previous
embodiment).
For example, the distracting unit is identified by the number 902 and this
is in parallel with the distracting unit 802 of the implant 800. The
distracting body is identified by the number 904 in paraflef with the
distracting body 804 of the implant 800. Focusing on Fig. 90, the
distracting unit 902 is depicted in a perspective view. The distracting
unit includes slot 906 which is wider at the top than at the bottom.
The reason for this is that the wider upper portion of the slot 906,
which is wider than the second wing 924 (Fig. 89), is used to allow
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the surgeon to easily place the second wing 924 into the slot 906 and
allow the wedge-shaped slot 906 to guide the second wing 924 to its
final resting position. As can be see in Fig. 91, in the final resting
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position, the largest portion of the slot 906 is not completely filled by
the second wing 924.
The end 908 of implant 900 is different in that it is more
pointed, having sides 909 and 911 which are provided at about 450
angles (other angles, such as by way of example only, from about 30
to about 60 are within the spirit of the invention), with a small flat tip
913 so that the body 904 can be more easily urged between the
spinous processes.
The distracting unit 902 further includes a tongue-shaped recess
919 which extends from the slot 906. Located in'the tongue-shaped
recess is a threaded bore 920.
As can be seen in Fig. 89, a second wing 924 includes a tongue
948 which extends substantially perpendicular thereto and between
the upper and lower portions 926, 928. The tab 948 includes a bore
950. With the second wing 924 positioned in the slot 906 of the
distracting unit 902 and tab 948 positioned in recess 919, a threaded
set screw 922 can be positioned through the bore 950 and engage the
threaded bore 920 in order to secure the second wing or retaining unit
924 to the distracting unit 902. The embodiment 900 is implanted in
the same manner as embodiment 800 previously described. In
addition, as the bore 922 is substantially perpendicular to the
distracting body 904 (and not provided at an acute angle thereto), the
surgeon can even more easily secure the screw in place from a
position directly behind the spinous processes.
Industrial Applicability
From the above, it is evident that the present invention can be
used to relieve pain caused by spinal stenosis in the form of, by way
of example only, central canal stenosis or foraminal (lateral) stenosis.
These implants have the ability to flatten the natural curvature of the
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spine and open the neural foramen and the spacing between adjacent
vertebra to relieve problems associated with the above-mentioned
lateral and central stenosis. Additionally, the invention can be used to
relieve pain associated with facet arthropathy. The present invention
is minimally invasive and can be used on an outpatient basis.
Additional aspects, objects and advantages of the invention can
be obtained through a review of the appendant claims and figures.
It is to be understood that other embodiments can be fabricated
and come within the spirit and scope of the claims.
