U.S. patent application number 14/569218 was filed with the patent office on 2015-06-18 for translational instrumentation for spondylolisthesis and scoliosis reduction.
The applicant listed for this patent is Tenzin LLC. Invention is credited to Paul Glazer.
Application Number | 20150164494 14/569218 |
Document ID | / |
Family ID | 48173139 |
Filed Date | 2015-06-18 |
United States Patent
Application |
20150164494 |
Kind Code |
A1 |
Glazer; Paul |
June 18, 2015 |
TRANSLATIONAL INSTRUMENTATION FOR SPONDYLOLISTHESIS AND SCOLIOSIS
REDUCTION
Abstract
An instrument includes a distraction mechanism having a proximal
end and an opposed distal end. The distal end includes opposed
first and second end members. A first vertebral endplate spreader
includes a proximal spreader section mounted to the first end
member of the distraction mechanism. The first spreader also
includes a distal spreader section operatively connected to the
proximal spreader section for lateral movement relative to the
proximal spreader section. A second vertebral endplate spreader is
mounted to the second end member of the distraction mechanism. The
distraction mechanism is configured and adapted to distract the
spreaders apart and to retract the spreaders together along a
distraction axis. The distal spreader section of the first spreader
is configured to move relative to the second spreader in a lateral
direction relative to the distraction axis for correction of
vertebral alignment, as in treatment of spondylolisthesis,
scoliosis, and the like.
Inventors: |
Glazer; Paul; (Chestnut
Hill, MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Tenzin LLC |
Chestnut Hill |
MA |
US |
|
|
Family ID: |
48173139 |
Appl. No.: |
14/569218 |
Filed: |
December 12, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13287811 |
Nov 2, 2011 |
8936599 |
|
|
14569218 |
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Current U.S.
Class: |
606/90 |
Current CPC
Class: |
A61B 17/7077 20130101;
A61B 2017/0256 20130101; A61B 17/025 20130101 |
International
Class: |
A61B 17/02 20060101
A61B017/02 |
Claims
1. An instrument for spinal procedures comprising: a distraction
mechanism having a proximal end and an opposed distal end, wherein
the distal end includes opposed first and second end members; a
first vertebral endplate spreader including a proximal spreader
section mounted to the first end member of the distraction
mechanism, and including a distal spreader section operatively
connected to the proximal spreader section for lateral movement
relative to the proximal spreader section, wherein the distal
spreader section is configured and adapted to engage a vertebra;
and a second vertebral endplate spreader mounted to the second end
member of the distraction mechanism, the second spreader being
configured and adapted to engage a vertebra, wherein the
distraction mechanism is configured and adapted to distract the
spreaders apart and to retract the spreaders together along a
distraction axis responsive to action imparted on the proximal end
of the distraction mechanism, and wherein the distal spreader
section of the first spreader is configured to move relative to the
second spreader in a lateral direction relative to the distraction
axis for correction of vertebral alignment.
2. An instrument as recited in claim 1, further comprising a pair
of guides engaged with the proximal and distal spreader sections to
maintain a parallel relationship between the proximal and distal
spreader sections during relative lateral travel of the proximal
and distal spreader sections.
3. An instrument as recited in claim 2, wherein the guides are
mounted to the distal spreader section and are slideably engaged to
the proximal spreader section.
4. An instrument as recited in claim 1, further comprising a linear
actuator engaged with the proximal and distal spreader sections to
actuate relative lateral travel of the proximal and distal spreader
sections.
5. An instrument as recited in claim 4, wherein the linear actuator
includes a threaded screw engaged to threads in the proximal
spreader section, and rotatably engaged with the distal spreader
section so rotation of the threaded screw adjusts separation of the
proximal and distal spreader sections for relative lateral travel
thereof.
6. An instrument as recited in claim 1, wherein at least one of the
proximal and distal spreader sections includes a bone screw passage
for accommodating a bone screw to engage the distal spreader
section to a vertebra.
7. An instrument as recited in claim 1, wherein the distal spreader
section of the first spreader and the second spreader each include
at least one tong for engaging opposed vertebral endplates for
distraction of opposed vertebrae.
8. A vertebral endplate spreader for a vertebral distraction
instrument comprising: a proximal spreader section configured to be
mounted to an end member of a distraction mechanism; and a distal
spreader section operatively connected to the proximal spreader
section for lateral movement relative to the proximal spreader
section, wherein the distal spreader section is configured and
adapted to engage a vertebra.
9. A vertebral endplate spreader as recited in claim 8, further
comprising a pair of guides engaged with the proximal and distal
spreader sections to maintain a parallel relationship between the
proximal and distal spreader sections during relative lateral
travel of the proximal and distal spreader sections.
10. A vertebral endplate spreader as recited in claim 9, wherein
the guides are mounted to the distal spreader section and are
slideably engaged to the proximal spreader section.
11. A vertebral endplate spreader as recited in claim 8, further
comprising a linear actuator engaged with the proximal and distal
spreader sections to actuate relative lateral travel of the
proximal and distal spreader sections.
12. A vertebral endplate spreader as recited in claim 11, wherein
the linear actuator includes a threaded screw engaged to threads in
the proximal spreader section, and rotatably engaged with the
distal spreader section so rotation of the threaded screw adjusts
separation of the proximal and distal spreader sections for
relative lateral travel thereof.
13. A vertebral endplate spreader as recited in claim 8, wherein at
least one of the proximal and distal spreader sections includes a
bone screw passage for accommodating a bone screw to engage the
distal spreader section to a vertebra.
14. A vertebral endplate spreader as recited in claim 8, wherein
the distal spreader section includes at least one tong for engaging
a vertebral endplate.
15. A method of correcting vertebral alignment comprising: engaging
a distal spreader section of a first vertebral endplate spreader to
a first vertebra; engaging a second vertebral endplate spreader to
a second vertebra proximate to the first vertebra; distracting the
first and second spreaders apart along a distraction axis to
distract the first and second vertebrae from one another; and
translating the distal spreader section of the first spreader
relative to the second spreader laterally relative to the
distraction axis for correction of alignment of the first and
second vertebrae.
16. A method as recited in claim 15, wherein the steps of engaging
the first and second spreaders to the vertebrae include approaching
the vertebrae with the spreaders from an anterior approach.
17. A method as recited in claim 16, wherein the step of
translating includes moving the superior of the two vertebrae in a
posterior direction to correct a listhesis condition of the
vertebrae.
18. A method as recited in claim 15, wherein the step of
translating includes moving the superior of the two vertebrae in an
anterior direction to correct a retrolisthesis condition of the
vertebrae.
19. A method as recited in claim 15, wherein the steps of engaging
the first and second spreaders to the vertebrae include approaching
the vertebrae with the spreaders from a lateral approach.
20. A method as recited in claim 19, wherein the step of
translating includes moving the two vertebrae relative to one
another in a lateral direction to correct a lateral slippage
condition of the vertebrae related to scoliosis.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to instruments and methods of
treating spinal conditions, and more particularly to instruments
and methods for treating spondylolisthesis, scoliosis, and the
like.
[0003] 2. Description of Related Art
[0004] Spondylolisthesis is a spinal disorder that arises from two
separate conditions. The first involves a lytic defect in the pars
interarticularis, otherwise known as a spondylolysis. The lytic
condition most commonly occurs where the lumbar spine meets the
sacrum, e.g., at L5-S1. The second condition involves a slippage of
the vertebra related to degenerated disc disease and facet
arthrosis. The degenerative condition usually involves L4-5
segments. However, spondylolisthesis can occur at any level in the
lumbar and less commonly in the cervical spine. Treatment of
spondylolisthesis often involves a fusion of the two vertebra
involved. Motion sparing technologies, such as total disc
replacements, are also used to treat milder cases of degenerative
spondylolisthesis.
[0005] Spondylolisthesis treatment options routinely include spinal
fusion procedures. These can be performed with a combined anterior
and posterior approach. The anterior approach is performed via a
direct anterior transperitoneal or retroperitoneal approach or
lateral approach. This surgery allows direct removal of the
majority of the disc, and placement of structural grafts in the
disc space. Graft materials include autogenous bone from the iliac
crest, allograft, and bone morphogenic protein. The discectomy
procedure allows a mobility of the motion segment and enhances
fusion rates. This is because anterior grafts are placed under
compression as compared to posterior fusion masses, which are under
tension. The broad surface area between the endplates allow for
higher fusion rates.
[0006] The distraction of the collapsed disc space of the listhetic
segment allows a mild reduction of the listhesis. This reduction is
enhanced by impacting a lordotically shaped graft within the
intervertebral space. Alternatively, motion sparing technologies
have been used for this problem. Posterior reduction techniques
using pedicle screw and rod systems have a significant risk of
nerve root traction injuries. None of the traditional instruments,
including instruments used in anterior approaches, allow for a
combination of both distraction of the disc space and correction of
listhesis.
[0007] Such conventional methods and systems have generally been
considered satisfactory for their intended purpose. However, there
is still a need in the art for instrumentation to allow for a
combination of distraction of the disc space and correction of the
listhesis. There also remains a need in the art for such
instrumentation that can be used from anterior and other
approaches. The present invention provides a solution for these
problems.
SUMMARY OF THE INVENTION
[0008] The subject invention is directed to a new and useful
instrument for spinal procedures, such as for treating
spondylolisthesis, scoliosis, and the like. The instrument includes
a distraction mechanism having a proximal end and an opposed distal
end. The distal end includes opposed first and second end members.
A first vertebral endplate spreader includes a proximal spreader
section mounted to the first end member of the distraction
mechanism. The first spreader also includes a distal spreader
section operatively connected to the proximal spreader section for
lateral movement relative to the proximal spreader section. The
distal spreader section is configured and adapted to engage a
vertebra.
[0009] A second vertebral endplate spreader is mounted to the
second end member of the distraction mechanism. The second spreader
is configured and adapted to engage a vertebra. The distraction
mechanism is configured and adapted to distract the spreaders apart
and to retract the spreaders together along a distraction axis
responsive to action imparted on the proximal end of the
distraction mechanism. The distal spreader section of the first
spreader is configured to move relative to the second spreader in a
lateral direction relative to the distraction axis for correction
of vertebral alignment.
[0010] In certain embodiments, a pair of guides is provided engaged
with the proximal and distal spreader sections to maintain a
parallel relationship between the proximal and distal spreader
sections during relative lateral travel of the proximal and distal
spreader sections. The guides can be mounted to the distal spreader
section and can be slideably engaged to the proximal spreader
section.
[0011] The instrument can include a linear actuator engaged with
the proximal and distal spreader sections to actuate relative
lateral travel of the proximal and distal spreader sections. The
linear actuator can include a threaded screw engaged to threads in
the proximal spreader section. The threaded screw can be rotatably
engaged with the distal spreader section so rotation of the
threaded screw adjusts separation of the proximal and distal
spreader sections for relative lateral travel thereof.
[0012] In another aspect, at least one of the proximal and distal
spreader sections can include a bone screw passage for
accommodating a bone screw to engage the distal spreader section to
a vertebra. It is also contemplated that the distal spreader
section of the first spreader and the second spreader each include
at least one tong for engaging opposed vertebral endplates for
distraction of opposed vertebrae.
[0013] The invention also provides a method of correcting vertebral
alignment. The method includes engaging a distal spreader section
of a first vertebral endplate spreader to a first vertebra and
engaging a second vertebral endplate spreader to a second vertebra
proximate to the first vertebra. The method includes a step of
distracting the first and second spreaders apart along a
distraction axis to distract the first and second vertebrae from
one another. The method also includes translating the distal
spreader section of the first spreader relative to the second
spreader laterally relative to the distraction axis for correction
of alignment of the first and second vertebrae.
[0014] The steps of engaging the first and second spreaders to the
vertebrae can include approaching the vertebrae with the spreaders
from an anterior approach. From such an anterior approach, the step
of translating can include moving the superior of the two vertebrae
in a posterior direction to correct a listhesis condition of the
vertebrae. It is also contemplated that the step of translating can
include moving the superior of the two vertebrae in an anterior
direction to correct a retrolisthesis condition of the
vertebrae.
[0015] The steps of engaging the first and second spreaders to the
vertebrae can include approaching the vertebrae with the spreaders
from a lateral approach. From a lateral approach, the step of
translating can include moving the two vertebrae relative to one
another in a lateral direction to correct a lateral slippage
condition of the vertebrae related to scoliosis.
[0016] These and other features of the systems and methods of the
subject invention will become more readily apparent to those
skilled in the art from the following detailed description of the
preferred embodiments taken in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] So that those skilled in the art to which the subject
invention appertains will readily understand how to make and use
the devices and methods of the subject invention without undue
experimentation, preferred embodiments thereof will be described in
detail herein below with reference to certain figures, wherein:
[0018] FIG. 1 is a side elevation view of an exemplary embodiment
of an instrument constructed in accordance with the present
invention, showing the vertebral endplate spreaders mounted to the
distal end of a hand operable mechanism for manipulating the
spreaders between distracted and retracted positions, and also
showing the driver tool for actuating lateral movement of the
distal sections of the upper and lower spreaders;
[0019] FIG. 2 is a plan view of the instrument of FIG. 1 without
the driver, showing the engagement of the spreaders to the hand
operable mechanism;
[0020] FIG. 3 is an exploded perspective view of the spreaders and
driver of FIG. 1, showing the tongs for engaging upper and lower
vertebrae;
[0021] FIG. 4 is an exploded perspective view of the upper and
lower spreaders of FIG. 3, showing the separate proximal and distal
sections of the each spreader as viewed from above;
[0022] FIG. 5 is a side elevation view of the instrument of FIG. 1,
showing the instrument being introduced from an anterior approach
to a listhetic pair of lumbar vertebrae;
[0023] FIG. 6 is a side elevation view of the instrument of FIG. 1,
showing the tongs of the instrument being positioned between the
listhetic vertebrae;
[0024] FIG. 7 is a side elevation view of the instrument of FIG. 1,
showing the upper and lower spreaders of the instrument mounted to
the respective vertebrae;
[0025] FIG. 8 is a side elevation view of the instrument of FIG. 1,
showing the upper and lower spreaders of the instrument distracting
the listhetic vertebrae; and
[0026] FIG. 9 is a side elevation view of the instrument of FIG. 1,
showing the upper and lower spreaders laterally translated relative
to one another for correction of the listhesis.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0027] Reference will now be made to the drawings wherein like
reference numerals identify similar structural features or aspects
of the subject invention. For purposes of explanation and
illustration, and not limitation, a partial view of an exemplary
embodiment of an instrument in accordance with the invention is
shown in FIG. 1 and is designated generally by reference character
100. Other embodiments of instruments in accordance with the
invention, or aspects thereof, are provided in FIGS. 2-9, as will
be described. The system of the invention can be used to treat
spondylolisthesis, scoliosis, and the like.
[0028] Instrument 100 includes a distraction mechanism 102 having a
proximal end 104 and an opposed distal end 106. Distal end 106
includes opposed first and second end members 108 and 110,
respectively. A first vertebral endplate spreader 112 includes a
proximal spreader section 114. Proximal spreader section 114 is
mounted to first end member 108 of distraction mechanism 102 by
mounting pin 122 shown in FIG. 2. First spreader 112 also includes
a distal spreader section 116 operatively connected to proximal
spreader section 114 for lateral movement relative to proximal
spreader section 114. A second vertebral endplate spreader 118 is
mounted to second end member 110 of distraction mechanism 102 by
mounting pin 124, which is identified in FIG. 1. The first and
second spreaders 112 and 118 are each configured to engage a
respective vertebra for correction of vertebral alignment as will
be described in greater detail below.
[0029] Distraction mechanism 102 is configured and adapted to
distract the spreaders 112 and 118 apart from one another and to
retract the spreaders 112 and 118 together along a distraction axis
A responsive to action imparted on proximal end 104 of distraction
mechanism 102. For example, if a user squeezes the handles of
proximal end 104, spreaders 112 and 118 will be distracted apart
from one another, and if a user allows the handles of proximal end
104 to move apart, for example by action of spring 120, spreaders
112 and 118 will be retracted towards one another.
[0030] Referring now to FIG. 3, in addition to being able to move
together and apart along distraction axis A, spreaders 112 and 118
can also move laterally with respect to one another, i.e., in a
lateral direction relative to distraction axis A. This lateral
movement is made possible by the fact that the spreaders 112 and
118 are each split into proximal and distal sections 114 and 116 to
vary the offset as needed by the preexisting listhesis. Driver 126
is used to turn actuator screws 128 to actuate the displacement of
distal spreader sections 116 relative to proximal spreader sections
114.
[0031] Lateral actuation of spreaders 112 and 118 is further
described with reference to FIG. 4, which shows parts of spreaders
112 and 118 separated and in the orientation of the procedures
described below with reference to FIGS. 5-9. A pair of guides 130
is provided for each spreader 112 and 118, engaged with the
proximal and distal spreader sections 114 and 116 to maintain a
parallel relationship between the proximal and distal spreader
sections 114 and 116 during relative lateral travel thereof. Guides
130 are rigidly mounted in bores 132 of distal spreader sections
116 and are slideably engaged in bores 134 of proximal spreader
sections 114.
[0032] A linear actuator is provided in each spreader 112 and 118
in the form of actuator screw 128, the threads of which engage with
corresponding threads in bore 138 of the respective proximal
spreader section 114. Each actuator screw 128 is rotatably engaged
to a respective distal spreader section 116, with actuator pins 140
mounted in bores 142 and engaged with groove 144 of each respective
actuator screw 128. Rotation of actuator screw 128 adjusts
separation of the proximal and distal spreader sections 114 and 116
for relative lateral travel thereof.
[0033] Each distal spreader section 116 includes two bone screw
bores 146 to provide passages for bone screws to affix each distal
spreader section 112 to a respective vertebra. Proximal spreader
sections 114 includes bone screw grooves 148 to provide passage for
bone screws and any suitable driver device for affixing distal
spreader sections 112 to respective vertebra. Each of the distal
spreader sections 116 includes a pair of tongs 150 for engaging
opposed vertebral endplates for distraction of opposed vertebrae,
as described in greater detail below.
[0034] Referring now to FIGS. 5-9, exemplary methods are described
of using instrument 100 for correction of vertebral alignment. FIG.
5 schematically shows instrument 100 approaching listhetic
vertebrae L4 and L5 from an anterior approach. The upper or first
spreader 112 has its distal spreader section 116 with corresponding
tongs 150 in a retracted position. The lower or second spreader 118
has its distal spreader section 116 and corresponding tongs in an
advanced position. The relative positions of the upper and lower
distal spreader sections 116 corresponds to the offset in alignment
of the L4 and L5 vertebrae. As indicated in FIG. 6, tongs 150 of
distal spreader section 116 of first spreader 112 are engaged to
the listhetic endplate of the L4 vertebra, i.e., the superior or
cephalad of the two listhetic vertebrae, and prongs 150 of second
spreader 118 are engaged to the adjacent endplate of the L5
vertebra, i.e., the inferior or caudal vertebra.
[0035] With instrument 100 engaged with the listhetic vertebrae as
shown in FIG. 6, the vertebrae can be distracted apart as shown in
FIGS. 8 and 9. FIG. 7 shows bone screws affixing the first and
second spreaders 112 and 118 to the respective vertebrae prior to
distraction. Those skilled in the art will readily appreciate that
one or both spreaders 112 and 118 can be affixed with bone screws
before or after distraction without departing from the spirit and
scope of the invention. Moreover, bone screw affixation may be
omitted for one or both of the spreaders 112 and 118, for example
if the forces engaging the respective prongs 150 to the vertebrae
provide sufficient fixation without bone screws. Having both
spreaders 112 and 118 secured with screws to the respective
vertebrae provides extra stability.
[0036] With the spreaders 112 and 118 affixed to the respective
vertebrae as shown in FIG. 7, the proximal end 104 of distraction
mechanism 102 can be actuated to distract the vertebrae along
distraction axis A as indicated by the heavy arrows in FIG. 8. With
the listhetic vertebrae L4 and L5 distracted, a corpectomy,
discectomy, or the like can be performed as needed.
[0037] Referring now to FIG. 9, direct posterior translational
force is applied after a thorough discectomy and distraction has
been performed. In order to correct the listhesis, driver 126 is
engaged with actuator screw 128 up upper spreader 112 and turned to
spread the upper proximal and distal spreader sections 114 and 116
apart. The actuator screw 128 on lower spreader 118 can also be
turned to move the lower distal spreader section 116 in the
opposite direction. This action translates the distal spreader
sections 116 relative to the proximal spreader sections 114
laterally with respect to distraction axis A for correction of
alignment of the L4 and L5 vertebrae. The action of driver 126 and
distal spreader sections 116 are indicted by the heavy arrows of
FIG. 9. Universal joint 152 accommodates a range of angles of
approach for driver 126 for ease of application. Driver 126 is
depicted with a female hex head, which those skilled in the art
will readily appreciate is exemplary, as any suitable driver/head
type or linear actuator type can be used without departing from the
spirit and scope of the invention.
[0038] During an operation as described above, the surgeon can
decide whether a complete or partial reduction of the listhesis
should be attempted. After adequate reduction has been achieved, an
interbody graft or motion sparing device can be placed through the
enhanced slot between the superior and inferior distractor tongs
150. The surgeon can check by direct visualization or
intra-operative x-rays as to the vertebral alignment and placement
of the interbody graft(s) or motion sparing device. If a fusion is
performed, instrument 100 is then removed, including the anterior
screws. Supplemental anterior plate fixation can then be applied
using the holes previously made in the vertebrae to affix the
spreaders 112 and 118. The bores 134 in spreader 112 and
corresponding bores 134 in spreader 118 are spaced apart to allow
for a corresponding anterior plating system after the reduction has
been performed.
[0039] Instrument 100 will thus allow a correction of vertebral
alignment related to spondylolisthesis. The systems and methods
described herein can also be applied for a retrolisthesis, which is
a much less common spinal condition. In this case, the lateral
motion of distal spreader sections 116 is reversed to be anterior
rather than posterior. Furthermore, it is also contemplated that a
smaller version of instrument 100 can be used for other
applications where smaller size is needed, for example in use on
the cervical spine.
[0040] In the orientation shown in FIGS. 5-9, first spreader 112
may be referred to as the upper, superior, or cephalad spreader,
and second spreader 118 may be referred to as the lower, inferior,
or caudal spreader. Those skilled in the art will readily
appreciate that while each of the spreaders 112 and 118 is shown
and described as split into proximal and distal sections 116 and
114 for lateral movement, it is also possible to use only one split
spreader with another spreader that is not split without departing
from the spirit and scope of the invention. If both spreaders are
split as described above, additional lateral travel is possible
compared to embodiments having only one spreader that is split.
[0041] While described above in the exemplary context of
spondylolisthesis, it is contemplated that other conditions can
also be treated using the systems and methods of the invention. For
example, there are several forms of scoliosis. These include
congenital, idiopathic, and degenerative forms. Deformity of the
spine involves a lateral or coronal curvature of the spine. In the
lumbar spine, especially in degenerative scoliosis, there is often
a lateral slippage of one vertebra relative to another. The
instrumentation described above to reduce an anterior
spondylolisthesis can be used in a lateral approach on the
convexity of the curve to reduce the scoliosis and at the same time
allow intervertebral distraction. An instrument adapted from
instrument 100 for treating scoliosis or similar applications can
be of a smaller diameter and can have one prong on each of the
spreaders instead of the two prongs 150 shown and described
above.
[0042] The methods and instruments described herein advantageously
allow for both distraction and relative lateral repositioning of
vertebrae. Additional advantages include allowing for disc space
distraction which enhances foraminal height. This increased
foraminal height reduces the potential for nerve root entrapment
during a reduction of the listhesis.
[0043] The methods and systems of the present invention, as
described above and shown in the drawings, provide for methods and
instruments for correcting misalignment of vertebrae with superior
properties including distracting and laterally repositioning
vertebrae with the same instrument. While the apparatus and methods
of the subject invention have been shown and described with
reference to preferred embodiments, those skilled in the art will
readily appreciate that changes and/or modifications may be made
thereto without departing from the spirit and scope of the subject
invention.
* * * * *