U.S. patent application number 11/982184 was filed with the patent office on 2008-03-20 for spinal alignment system and related methods.
This patent application is currently assigned to Nu Vasive, Inc.. Invention is credited to Bret A. Ferree.
Application Number | 20080071276 11/982184 |
Document ID | / |
Family ID | 23066909 |
Filed Date | 2008-03-20 |
United States Patent
Application |
20080071276 |
Kind Code |
A1 |
Ferree; Bret A. |
March 20, 2008 |
Spinal alignment system and related methods
Abstract
A spinal alignment system is disclosed and includes vertebral
connectors, elongated elements that link the vertebral connectors,
and fasteners that lock the elongated elements in position. An
elongated element has at least one shaped end that is received by a
coupling member of the connector. The shaped end permits the
elongated element to be angularly moveable with respect to the
coupling member until locked in place with a fastener received in
the coupling member. The elongated element also preferably includes
a length adjustment mechanism, such as a telescoping or threaded
section to provide a desired length in conjunction with a desired
degree of alignment. Various coupling mechanisms are disclosed to
provide multiple degrees of freedom prior to fixation.
Inventors: |
Ferree; Bret A.;
(Cincinnati, OH) |
Correspondence
Address: |
JONATHAN SPANGLER;NU VASIVE, INC.
4545 TOWNE CENTRE COURT
SAN DIEGO
CA
92121
US
|
Assignee: |
Nu Vasive, Inc.
San Diego
CA
|
Family ID: |
23066909 |
Appl. No.: |
11/982184 |
Filed: |
October 31, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10894533 |
Jul 19, 2004 |
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11982184 |
Oct 31, 2007 |
|
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10105971 |
Mar 25, 2002 |
6802844 |
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10894533 |
Jul 19, 2004 |
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Current U.S.
Class: |
606/258 ;
606/103 |
Current CPC
Class: |
A61B 17/7053 20130101;
A61B 17/7014 20130101; A61B 17/7052 20130101; A61B 17/7022
20130101; A61B 17/7005 20130101; A61B 17/7011 20130101; A61B 17/705
20130101; A61B 17/7025 20130101; A61B 2017/7073 20130101; A61B
17/701 20130101 |
Class at
Publication: |
606/061 ;
606/103 |
International
Class: |
A61B 17/58 20060101
A61B017/58 |
Claims
1. A system for fixing relative to each other the position of a
first spinal vertebra and a second spinal vertebra, comprising: a
rigid elongated element having a shaped end and a rod segment, said
elongated element dimensioned to span between a first vertebra and
a second vertebra and said rod segment including a first rod
portion adjacent to said shaped end and a second rod portion
located a distance from said shaped end; a first connector
anchorable to said first vertebra and having a receiver portion,
said receiver portion including a peripheral body formed about a
space for receiving said shaped end of said elongated element and a
surface within said space, said surface being complementary to said
shaped end, and said peripheral body having at least one trough for
passage of said first rod portion when said shaped end is received
within said space and inner threading for complementary engagement
with external threading on a first fastener for locking said shaped
end within said space; a second connector anchorable to said second
vertebra and having a receiver portion configured to receive said
second rod portion and engage a second fastener for locking said
second rod portion to said second connector.
2. The system of claim 1, wherein said shaped end is at least
partially spherical.
3. The system of claim 1, wherein said surface of said receiver
portion is at least partially spherical.
4. The system of claim 1, wherein said surface of said receiver
portion and said shaped end form a ball-and-socket.
5. The system of claim 1, wherein said at least one trough has a
curved surface.
6. The spinal alignment system of claim 1, wherein said first and
second vertebrae are at adjacent vertebral levels within the
spine.
7. The spinal alignment system of claim 1, wherein said first and
second vertebrae are not at adjacent vertebral levels within the
spine.
8. The spinal alignment system of claim 7, further including a
third connector anchorable to a third vertebra located between said
first vertebra and said second vertebra, said connector having a
receiver portion configured to receive a third rod portion located
between said first rod portion and said second rod portion and to
engage a third fastener for locking said third rod portion to said
third connector.
9. The system of claim 1, further comprising: a second elongated
element dimensioned to span between said first vertebra and said
second vertebra on the opposite side of said first and second
vertebra from said first elongated element; and a second pair of a
connectors anchorable into said first and second vertebrae, and
receiver portions configured to receive said second elongated
element
10. The spinal alignment system of claim 9, wherein said first
elongated element and said second elongated element are connected
by a transverse connector.
11. The spinal alignment system of claim 10, wherein said second
elongated element is one of generally parallel and not generally
parallel to said first elongated element.
Description
CROSS REFERENCES TO RELATED APPLICATIONS
[0001] The present application claims priority under 35 U.S.C.
.sctn. 120 from the commonly owned and co-pending U.S. patent
application Ser. No. 10/894,533, filed on Jul. 19, 2004, which
itself claims priority under 35 U.S.C. .sctn. 120 from U.S. patent
application Ser. No. 10/105,971, filed on Mar. 25, 2002, now issued
as U.S. Pat. No. 6,802,844, the complete disclosures of which are
hereby incorporated herein by reference in their entireties for all
purposes. Additionally, the present application claims benefit
under 35 U.S.C. .sctn. 119(e) from U.S. Provisional Application
Ser. No. 60/278,910, filed on Mar. 26, 2001, the entire contents of
which are hereby expressly incorporated by reference into this
disclosure as if set forth fully herein.
BACKGROUND OF THE INVENTION
[0002] I. Field of the Invention
[0003] This invention relates generally to instrumentation, tools
and techniques associated with spinal fixation and, in particular,
to apparatus and methods facilitating spinal correction in multiple
dimensions.
[0004] II. Description of the Related Art
[0005] The human spine exhibits some degree of curvature at
different levels to facilitate normal physiologic function.
Correction may be required when this curvature deviates
substantially. A common problem is lateral deviation of the spine,
commonly termed scoliosis.
[0006] Spinal deformity occurs when a patient has abnormal frontal
or sagittal plane alignment. At the same time, the cervical and
lumbar spine exhibit lordosis, while the thoracic spine has
kyphosis. Thus, when performing spinal fusion, surgeons may be
required to preserve or restore both front plane and sagittal
alignment while taking lordosis and kyphosis into account.
[0007] As discussed in U.S. Pat. No. 5,540,689, the first
successful internal fixation method for surgically treating
scoliosis used the Harrington instrumentation system. According to
this technique, a rigid rod with hooks at each end is implanted
adjacent the concave side of the scoliotic spine. The spine is
manually straightened to a desired extent and a distraction rod is
used to maintain the correction by exerting vertical forces at each
end. The rod commonly has a ratcheted end over which hooks are
slidably mounted and locked in place. To accommodate lordosis, a
compression rod is sometimes placed on the convex side of the
scoliotic spine.
[0008] The Harrington instrumentation system has been used
successfully for some time, but because the distraction rod is
fixed to the spine in only two places, failure at either end causes
the entire system to fail. Another deficiency with existing
mechanisms and approaches is that the single rod used to correct
the defects must be contoured to fit various attachment sites. In
patients having compound spinal deformity, this may be extremely
difficult. A further problem is that the contoured rod frequently
limits further correction of certain types of deformities. That is,
once the rod is in position, further correction of the deformity is
difficult, since existing systems tend to limit incremental
alignment procedures.
[0009] An alternative treatment has since evolved which takes
advantage of segmented fixation. According to this method, a rod is
fixed to the spine at multiple points by means of sublaminar wires
which run underneath the lamina of the vertebra and around the rod.
The use of multiple fixation sites enhances stability and reduces
the need for additional post-operative bracing.
[0010] Sublaminar fixation utilizing current devices has two
primary weaknesses, however. First, the wires are simply wrapped
around the rod, resulting in a rod to cable junction which is not
rigid. Second, the thin wires can cut in some instances right
through the lamina.
[0011] U.S. Pat. No. 6,019,759 uses multiple longitudinal members
with flat plates that attach using hooks or screws. However, the
plates are stacked on top of one another at each attachment site,
resulting in an overall structure that tends to be quite thick.
Systems having a high sagittal profile are often thick enough to be
felt through the skin. Additionally, the teachings of the '759
patent do not allow for easy correction or preservation of sagittal
alignment.
[0012] The need remains, therefore, for a system and method that
allows incremental correction of spinal defects, ideally in all
three dimensions.
SUMMARY OF THE INVENTION
[0013] This invention resides in spinal alignment apparatus,
including implantable components, instrumentation, and methods of
use. In broad and general terms, the preferred embodiment includes
bodies which connect to the vertebra to be aligned, and elongated
elements that connect to the bodies. The elements are preferably
adjustable relative to the bodies in multiple dimensions, with
locking mechanisms that allow the alignment to proceed in an
orderly fashion until a desired degree of correction is
achieved.
[0014] Each rigid, elongated element has at least one end
terminating in the first portion of the lockable coupling
mechanism. The vertebral connector bodies each include a feature
for attaching the body to a respective vertebrae, and the second
portion of the lockable coupling mechanism. This arrangement
permits the elongated elements to be adjusted in multiple
dimensions relative to a given connector body prior to being
lockingly coupled thereto.
[0015] The feature for attaching the body to its respective
vertebrae may include a pedicle screw or, alternatively, a shape
such as a hook adapted for sublaminar engagement. The elongated
elements may also preferably include a length adjustment mechanism,
such as a telescoping or threaded section, to provide a desired
length in conjunction with a desired degree of alignment.
[0016] Various coupling mechanisms are disclosed to provide
multiple degrees of freedom prior to fixation. In the preferred
embodiment, the mechanism includes a fixed or adjustable-length rod
having ball-shaped ends coupled to a vertebral connector providing
multiple degrees of freedom before being locked into position once
a desired orientation is achieved.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Many advantages of the present invention will be apparent to
those skilled in the art with a reading of this specification in
conjunction with the attached drawings, wherein like reference
numerals are applied to like elements and wherein:
[0018] FIG. 1A is a frontal view of elongated rods and hooks
currently used to correct spinal defects;
[0019] FIG. 1B shows the use of two rods in place, attached to
multiple vertebrae;
[0020] FIG. 1C illustrates the way in which a typical prior-art
hook is positioned under the spinal lamina for rod insertion;
[0021] FIG. 2A is a frontal view of basic instrumentation according
to the present invention utilizing elongated members in the form of
links of different length as opposed to longer rods;
[0022] FIG. 2B shows the instrumentation of FIG. 2A in place
relative to multiple vertebrae;
[0023] FIG. 3A illustrates components associated with a preferred
embodiment of the present invention, including a one- and
multiple-opening pedicle screws, compound rods, tightening bands,
and fasteners;
[0024] FIG. 3B is a detail drawing of a single-opening pedicle
screw according to the present invention;
[0025] FIG. 3C is a top-down view of the single-opening pedicle
screw of FIG. 3B;
[0026] FIG. 3D is a detail drawing of a multi-opening pedicle screw
according to the present invention;
[0027] FIG. 3E is a top-down view of the multi-opening pedicle
screw of FIG. 3D;
[0028] FIG. 3F shows a preferred setscrew fastener according to the
present invention for use with the single- and multi-opening
fasteners of FIGS. 3A through 3E;
[0029] FIG. 3G shows the way in which caps may be added to
elongated members according to the present invention to produce
spherical or semi-spherical endings;
[0030] FIG. 3H shows the way in which multiple elongated members
may be interconnected to produce a single spherical or
semi-spherical joint region;
[0031] FIG. 3I illustrates components associated with an
alternative embodiment of the invention, including a pedicle screw,
swivel connector and locking links;
[0032] FIG. 3J illustrates an embodiment of the invention similar
to that depicted in FIG. 3I, but wherein the pedicle screw includes
a threaded end as opposed to a ball-end-socket type of
connection;
[0033] FIG. 3K is a side view of a preferred transverse connector
according to the invention;
[0034] FIG. 3L is a top view of the transverse connector of FIG.
3K;
[0035] FIG. 3M is a top view of the transverse connector of FIG.
3K, illustrating multiple degrees of freedom made possible by the
arrangement;
[0036] FIG. 3N depicts multiple views of the preferred transverse
connector of FIG. 3K, showing various degrees of angulation;
[0037] FIG. 3o illustrates the use of a ball joint that permits the
preferred transverse connector to accommodate non-parallel
rods;
[0038] FIG. 3P is an end view of the preferred transverse connector
used to illustrate the desirability of reduced dimensions;
[0039] FIG. 4A illustrates a sublaminar hook according to the
invention having a ball-shaped connector;
[0040] FIG. 4B illustrates a sublaminar hook according to the
invention having a threaded connector;
[0041] FIG. 4C illustrates a sublaminar hook embodiment of the
invention featuring two opposing spherical joints;
[0042] FIG. 4D illustrates a sublaminar hook embodiment of the
invention featuring a single spherical joint;
[0043] FIG. 5A illustrates one use of cross-links according to the
invention;
[0044] FIG. 5B illustrates an alternative cross-link configuration
according to the invention;
[0045] FIG. 6A shows the use of clamps as part of a first step to
realign vertebrae for use with at least one embodiment of the
invention;
[0046] FIG. 6B shows the vertebrae in alignment using the clamps of
FIG. 6A;
[0047] FIG. 6C shows the installation of linking rods to align the
vertebrae, enabling the clamps to be removed;
[0048] FIG. 7A shows a first step associated with restoring frontal
alignment according to the present invention;
[0049] FIG. 7B illustrates an initial application of rods to
restore frontal alignment;
[0050] FIG. 7C illustrates an intermediate rod installation;
[0051] FIG. 7D illustrates a completed rod-and-connector structure
to restore frontal alignment;
[0052] FIG. 8A illustrates a first step associated with restoring
sagittal alignment;
[0053] FIG. 8B shows two vertebrae with appropriate sagittal
alignment in preparation for rod insertion;
[0054] FIG. 8C shows the vertebrae of FIGS. 8A and 8B, with a
linking rod in place and a tool and the tool removed;
[0055] FIG. 9 illustrates the use of a tool used to remove a
connector from a ball-tip type of pedicle screw according to the
present invention;
[0056] FIG. 10 depicts an alternative embodiment of the present
invention, wherein connectors include multiple apertures for
linking bars;
[0057] FIG. 11A shows the configuration of FIG. 10 with lines
indicating a desired placement of cross-members;
[0058] FIG. 11B shows the linking members of FIGS. 10 and 11A with
optional sublaminar cabling;
[0059] FIG. 12A is a drawing of an alternative connector having
multiple apertures for linking bars or other elements;
[0060] FIG. 12B shows the alternative connector of FIG. 12A with
lines indicating one possibility for cross-linking;
[0061] FIG. 13 shows the use of diagonal connectors according to
the invention for use with existing rod- or plate-alignment
systems;
[0062] FIG. 14 shows diagonal connectors for use with existing rod
or plate systems, but with attachment made relative to the pedicle
screws as opposed to the linking members;
[0063] FIG. 15A illustrates an alternative embodiment wherein
struts are stacked over one another onto pedicle screws;
[0064] FIG. 15B illustrates the use of cross-link member in
conjunction with the embodiment of FIG. 15A;
[0065] FIG. 16 is a side-view drawing of yet a further alternative
connector according to the invention wherein more space is provided
to tighten and loosen associated pedicle screws;
[0066] FIG. 17 shows a telescoping rod that may be adapted for use
with any of the embodiments described herein;
[0067] FIG. 18A illustrates a sublaminar hook having swivel
connectors to which the ends of the telescoping rod of FIG. 17 may
attach;
[0068] FIG. 18B is a top-down view of the hook of FIG. 18A;
[0069] FIG. 18C is a cross-sectional view of the hook of FIG.
18A;
[0070] FIG. 19 illustrates a pedicle-screw version of the hook of
FIG. 18A, also including locking connectors that swivel;
[0071] FIG. 20 is a side-view of the spine illustrating the
utilization of hook and pedicle-screw connectors according to one
embodiment of the present invention;
[0072] FIG. 21 is a top-view drawing of the spine, showing the use
of cross connectors employed in an angular fashion to maximize
rigidity;
[0073] FIG. 22A shows the way in which a telescoping connector
according to the invention is installed;
[0074] FIG. 22B illustrates an intermediate adjustment procedure
associated with the use of a telescoping rod according to the
invention;
[0075] FIG. 22C shows the telescoping rod locked into place once a
desired level of alignment is achieved;
[0076] FIG. 23 is a drawing of a threaded cross-connector according
to the invention;
[0077] FIG. 24 is a drawing of a telescoping rod according to the
invention having an arch feature that allows placement over arched
lamina;
[0078] FIG. 25 is a cross-sectional drawing of a transverse
connector according to the invention associated with a rod
junction;
[0079] FIG. 26A illustrates the use of a further alternative
embodiment of the invention featuring a telescoping rod that
engages with hooks having one or more posts;
[0080] FIG. 26B shows the rod of FIG. 26A being rotated to achieve
a desired level of alignment;
[0081] FIG. 26C is a close-up view of the rotation procedure;
[0082] FIG. 27 shows an alternative connector according to the
present invention providing the ability to vary angulation in two
planes;
[0083] FIG. 28 is an alternative connector according to the present
invention which also affords multiples degrees of freedom;
[0084] FIG. 29A depicts an alternative connector according to the
present invention that uses a ball and socket held in position with
a threaded fastener;
[0085] FIG. 29B shows the alternative connector of FIG. 29A locked
into a desired orientation;
[0086] FIG. 30A shows an embodiment of the invention wherein a
connector body and elongated element are integrally formed to
achieve a low-profile interconnection scheme;
[0087] FIG. 30B shows the configuration of FIG. 30A in an assembled
condition;
[0088] FIG. 30C shows the way in which connector bodies having
multiple male and female connectors may be joined together in
succession;
[0089] FIG. 31A shows a swiveling, socket-type connector according
to the invention on a body attached to a pedicle screw;
[0090] FIG. 31B shows the arrangement of FIG. 31A in an assembled
condition;
[0091] FIG. 31C is a series of top-down drawings illustrating the
swiveling feature of the embodiments of FIGS. 31A and 31B;
[0092] FIG. 32 shows a sublaminar hook having outward projections
to receive swivel connectors;
[0093] FIG. 33A is a drawing of a top-down view of a screw
connector having two posts;
[0094] FIG. 33B is a top view of a screw connector according to the
invention having a single post;
[0095] FIG. 33C is a top view of a single hook connector;
[0096] FIG. 33D is an oblique drawing that shows the use of
frictional surfaces to lock in the swivel action upon achieving a
desired orientation;
[0097] FIG. 33E shows how one or more manually adjustable fasteners
may be added to help control rotation of a connector according to
the invention;
[0098] FIG. 34A shows how a combined longitudinal member and
connector may have different lengths and angles to address
different alignment situations;
[0099] FIG. 34B illustrates an assembled version of an angled
unit;
[0100] FIG. 35 is a series of drawings that show a variety of
longitudinal members in straight and curved configurations;
[0101] FIG. 36A shows how a telescoping member may be assembled
through a pair of nuts, then joined;
[0102] FIG. 36B shows a joined assembled version of the assembly of
FIG. 36A;
[0103] FIG. 37 illustrates the combined use of ball-and-socket
connectors and rigid link plates;
[0104] FIG. 38 illustrates the overlapping of rigid link plates at
different vertebral levels;
[0105] FIG. 39 is a side view of a connector according to the
invention including a cross-link;
[0106] FIGS. 40A-40F provide different views of a central lumbar
connector according to the present invention;
[0107] FIGS. 41A-41G depict different views of a lumbar connector
adapted to the cephalad end;
[0108] FIGS. 42A-42E show different views of thoracic connectors
according to the invention;
[0109] FIGS. 43A and 43B show exploded and assembled views,
respectively, of sublaminar hooks with thoracic connectors attached
thereto;
[0110] FIGS. 44A-44C are top views showing swiveling before and
after locking into a straightened configuration;
[0111] FIG. 45 is a drawing of a pedicle screw used to discuss
different sizes and diameters;
[0112] FIG. 46 is a perspective view of the pedicle screw of FIG.
45 including a ball connector and link bar;
[0113] FIG. 47 shows the configuration of FIG. 46 in an assembled
state;
[0114] FIG. 48 is an assembled connector having two opposing
ball-receiving sockets;
[0115] FIG. 49 is an exploded and assembled view of a pedicle screw
having independent double connectors;
[0116] FIG. 50 shows how a non-round (in this case, oval)
interconnection may be used to prevent rotation of the pedicle
screw relative to a connector body;
[0117] FIG. 51 introduces the use of a hinged connector according
to the present invention;
[0118] FIG. 52A shows the hinge connector in an open condition;
[0119] FIG. 52B shows a hinge connector locked onto a rod;
[0120] FIGS. 53A-53M illustrate the alternative use of straps
according to the invention for rod movement and stabilization;
[0121] FIG. 54 is a side view of a turnbuckle rod according to the
invention;
[0122] FIG. 55 shows the combined use of ball-and-socket connectors
in crisscross link bars;
[0123] FIG. 56 shows how a half-washer may be used in conjunction
with a nut opening that is large enough to slide over the sphere at
the end of a rod;
[0124] FIG. 57 shows an alternative use of a slotted washer
permitting a nut to slide over the spherical end of a solid
rod;
[0125] FIG. 58A shows a modified connector adapted may be used to
reduce impingement;
[0126] FIG. 58B illustrates an anti-impingement connector utilizing
a ball-and-socket arrangement;
[0127] FIGS. 59A and 59B are different views of a transverse
connector according to the present invention;
[0128] FIG. 60 shows the combined use of transverse connectors and
hinged hooks that lock onto a solid rod;
[0129] FIG. 61 is a close-up, end view of a hinged connector
associated with an octagonal rod;
[0130] FIG. 62A illustrates the use of a continuous shaped rod, in
this case having a grooved cross-section;
[0131] FIG. 62B illustrates how the modification along the rod may
be interrupted according to the present invention;
[0132] FIG. 63 shows a bevel connector;
[0133] FIG. 64 illustrates the use of multiple rods on either side
of the spine;
[0134] FIG. 65A shows a stabilization clamp for use with various
embodiments disclosed herein;
[0135] FIG. 65B is an end of the configuration of FIG. 65A;
[0136] FIG. 66A is a different alternative embodiment of a
stabilizing assembly;
[0137] FIG. 66B is a cross-section of the assembly of FIG. 66A;
and
[0138] FIGS. 67A-67C illustrate the use of lockable swivel-type
connectors which may be fastened to one or, preferably a pair, of
alignment rods to provide a desired degree of alignment and
correction.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0139] Illustrative embodiments of the invention are described
below. In the interest of clarity, not all features of an actual
implementation are described in this specification. It will of
course be appreciated that in the development of any such actual
embodiment, numerous implementation-specific decisions must be made
to achieve the developers' specific goals, such as compliance with
system-related and business-related constraints, which will vary
from one implementation to another. Moreover, it will be
appreciated that such a development effort might be complex and
time-consuming, but would nevertheless be a routine undertaking for
those of ordinary skill in the art having the benefit of this
disclosure. The spinal alignment apparatus and related methods
disclosed herein boast a variety of inventive features and
components that warrant patent protection, both individually and in
combination.
[0140] FIGS. 1A through 1C present simplified representations
regarding the way in which prior-art hooks and rods are used to
treat spinal deformities. FIG. 1A shows a plurality of vertebrae
102 in need of alignment. In accordance with existing practice,
hooks 104 are fastened to the vertebrae at points deemed to be
useful by the attending surgeon. Tools are used in an attempt to
align the vertebrae, at which time rods 106 are contoured at the
time of the procedure to engage with the hooks 104 to maintain a
desired degree of straightening, as shown in FIG. 1B. FIG. 1C
illustrates the way in which a typical prior-art hook is positioned
under the spinal lamina for rod insertion.
[0141] FIG. 2A illustrates basic instrumentation according to one
embodiment of the invention. As opposed to the hooks 104 of
prior-art devices, rotating/swiveling connectors 204 are instead
used. In addition, as opposed to the rods 106 which currently must
be contoured, links 206 of varying fixed or adjustable length are
coupled to the connectors, and the entire structure locked into a
preferred orientation, as shown in FIG. 2B. Although
rotating/swiveling connectors having two rod-receiving positions
are shown, the preferred embodiment of FIG. 3 shows how compound
elements may be used for a single compression fitting and very low
profile.
[0142] FIG. 3A illustrates a preferred system according to the
invention, depicted generally at 10. Broadly, the system includes
single-opening bodies 20, multiple-opening bodies 40, and rods 80.
To afford additional degrees of freedom in multiple dimensions, the
invention contemplates the use of rods having ball-shaped ends as
well as the flattened plates of FIGS. 3I and 3J. Although the
ball-shaped ends are shown as joinable to permit a single
compression fastener as described below, it will be appreciated
that solid members with integral spherical/shaped ends may be used,
as well at the telescoping and other configurations disclosed with
reference to the various alternative embodiments.
[0143] FIG. 3B is a detail drawing of a single-opening connector
according to the invention, and FIG. 3C is a top-down view of the
single-opening device of FIG. 3B. The structure 20 includes a
rod-receiving body 22 coupled to a pedicle screw 24. The body
includes one opening 23 configured for a constrained connection and
a second opening 25 adapted for multiple degrees of freedom before
compression fastener 28 is tightened into threaded area 30. To
provide a solid mass, tension band 26 is positioned onto recesses
27 before tightening fastener 28. FIG. 3C shows the recesses 27
from above, as well as the bottom of hemispherical well 34 within
the body 22.
[0144] FIG. 3D is a detail drawing of a multiple-opening connector
40 according to the invention, and FIG. 3E is a top-down view of
the multi-opening device 40 of FIG. 3D, in this case a two-port
device. The structure 40 includes a rod-receiving body 42 coupled
to a pedicle screw 44. The body 42 includes one opening 43
configured for a first rod moveable in multiple dimensions, and a
second opening 45 for a second rod, also adapted for multiple
degrees of freedom before compression fastener 28 is tightened into
threaded area 50. To provide a solid mass, a tension band 26 is
positioned onto recesses 47 before tightening fastener 28. FIG. 3E
shows the recesses 47 from above, as well as the bottom of the
hemispherical well within the body 42. Note that in the preferred
embodiment the same tightening band 26 and setscrew 28 may be used
for both the single and multiple opening configurations.
[0145] FIG. 3F is a cross-sectional drawing of the preferred
compression fastener, in this case a setscrew 28 having an
allen-wrench-receiving top portion 62 and a hemispherical bottom
portion 64.
[0146] FIG. 3G is a drawing which shows the way in which caps may
be added to elongated members according to the invention to produce
spherical or semi-spherical endings. FIG. 3H shows the way in which
multiple elongated members may be interconnected to produce a
single spherical or semi-spherical joint region. In the preferred
embodiment, link members 80 have male/female half spheres allowing
either caps or additional rods to be attached. This not only
reduces the number of devices on the surgeon's tray, but it also
allows two rods to form a single ball unit for a smaller
profile.
[0147] In FIG. 3G, end 82 includes a male post 83, which receives
end cap 84 having female aperture 85. The other end of the rod
functions in like manner, with the male and female roles reversed.
Although the posts and apertures are not technically necessary,
they do allow the surgeon to pre-assemble components which hold
together prior to installation, thereby maximizing the use of both
hands. As shown in FIG. 3H, two rods may be connected to one
another as opposed to the end caps, thereby allowing the fastener
of FIGS. 3D and 3E to have rods extending from both sides. Note
that the rods of FIG. 3H may be turned at the joint region prior to
installation, thereby permitting the rods to extend from the
connector of FIGS. 3D and 3E at various angles prior to
tightening.
[0148] FIG. 3I illustrates an alternative connector system
according to the present invention. A pedicle screw 302 having a
hemispherical head 303 and a slot 306 (or alternatively a hex head
or other suitable tool-engaging feature) is driven into the
vertebrae at points useful for alignment. A connector body 204 is
placed over the exposed end of the screw 302 so that the head 303
engages with a corresponding opening 304 in the bottom of the
connector. A setscrew 307 or other fastener is used to lock the
body 204 in place relative to screw 302 and vertebrae to which it
is attached. At this point, the body 204 is able to swivel in three
dimensions until the devices are locked into place.
[0149] Link bars 206, preferably with enlarged ends are placed into
recesses 308 into the body 204, and these are locked into place
with setscrews 312 or other suitable fasteners. Again, until the
setscrews 312 are tightened down; the links 206 may have at least
some play until locked into place. Although short bars 206 of equal
length are illustrated, it will become apparent that the system is
quite flexible, and may take advantage of bars of different or
adjustable lengths and profiles. An aperture such as 314 may be
provided to enable a tool to move the connectors into a desired
position, or remove the body 204 from the screw 302, as
appropriate.
[0150] FIG. 3J illustrates an alternative embodiment of the
invention, wherein the swivel joint between the pedicle screw and
connector body is replaced with a screw 402 having a threaded end
406. The threaded end 406 now protrudes through a larger hole 414
in the connector body 404, enabling a nut 407 or other suitable
fastener to lock the body 404 onto the screw 402. Similar to the
embodiment of FIG. 3A, however, link bars 206 fit into recesses 408
in the body 404, and set screws 412, which mate with threads 410,
are similarly used to lock the link bars into place once a desired
orientation is achieved.
[0151] FIG. 3K is a side view of a preferred transverse connector
according to the invention. FIG. 3L is a top view of the transverse
connector of FIG. 3K, showing how bodies 92 clamp onto rods 90.
FIG. 3M is a top view of the transverse connector of FIG. 3K,
illustrating multiple degrees of freedom made possible by the
arrangement. FIG. 3N depicts multiple views of the preferred
transverse connector of FIG. 3K, showing various degrees of
angulation. FIG. 3o illustrates the use of a ball joint that
permits the preferred transverse connector to accommodate
non-parallel rods. FIG. 3P is an end view of the preferred
transverse connector used to illustrate the desirability of reduced
dimensions. In particular, dimensions X and Y are both reduced
according to the invention, and fastener 96 is not engaged until
the two halves of the unit are brought into close proximity.
[0152] FIGS. 4A and 4B are drawings of improved sublaminar hooks
constructed according to the invention. Broadly, these devices
include bodies such as 442 having a recess such as 443 configured
for engagement with sublamina, but in contrast to existing devices,
either a hemispherical connector 444 or threaded connector 446 are
provided on the body to engage with the inventive link connectors
discussed, for example, with reference to FIGS. 3A and 3B. FIG. 4C
illustrates a sublaminar hook embodiment of the invention featuring
two opposing spherical joints. FIG. 4D illustrates a sublaminar
hook embodiment of the invention featuring a single spherical
joint.
[0153] FIGS. 5A and 5B illustrate, respectively, two ways in which
connectors according to the invention may be cross-linked, with the
understanding that additional variations are certainly possible. In
FIG. 5A, longer link members 502 are used to link the sides of the
connector in crisscross fashion, whereas, in FIG. 5B, shorter link
members 504 are used in a manner transverse to those oriented from
foot-to-head along the spine. Note also that the plate and rod
connectors may be used separately or together; that is while it may
be advantageous to use plates at 502 and 504 for transverse
interconnection, spherical joints may be preferred longitudinally
along the spine, as in locations 510.
[0154] FIGS. 6A-6C illustrate the way in which instrumentation may
be used to obtain a desired degree of vertebral correction, at
which time the link members may be added to maintain the structure
in correct alignment. In FIG. 6A, vertebrae 610 and 620 are
mal-aligned, and instruments 602 and 604 are used to adjust them
into a proper orientation. Generally speaking, instrument 602 is
used to urge apart the connectors 612, 622 shown in the left part
of the drawing, where the vertebrae are too close to one another,
whereas instrument 604 is used to pull the vertebrae together.
[0155] FIG. 6B is a drawing which shows a desired orientation of
the connectors 612 and 622, without the vertebrae being shown, and
FIG. 6C illustrates how, having achieved a desired final position,
link members 630 and 632 are tightened onto the connectors 612 and
622, at which time the instruments may be removed. This process is
more or less repeated, on adjacent vertebral levels, until an
overall desired level of alignment is achieved. Given the ease with
which the link members and the connectors themselves may be
readjusted, the surgeon may readily go back over areas in need of
further refinement, as appropriate.
[0156] This process is shown in FIGS. 7A through 7D with respect to
the restoration of a frontal alignment. In FIG. 7A the spine is
curved as shown, with seven connectors being positioned by the
surgeon on the various vertebrae to begin the correction process.
In FIG. 7B, the connectors shown upwardly in the drawing are first
brought into alignment, and in FIG. 7C, cross-links and additional
link members have been added further down the spine. In FIG. 7D,
all of the connectors are linked up, with fine adjustments being
made in three dimensions, as necessary, for a desired degree of
correction. Again, although two rod-receiving positions are shown
with respect to each body, use of the bodies and link members of
FIGS. 3D through 3H would proceed in like fashion.
[0157] In restoring the frontal alignment just described, the
manual instruments of the type shown in FIGS. 6A-6C would be
appropriate, though they are not shown in FIGS. 7A-7C. To restore
sagittal alignment, a different form of instrument is preferred, to
raise and lower connectors as opposed to pushing and spreading.
Instruments according to the invention for this purpose are shown
in FIGS. 8A-8C. In FIG. 8A, a tool 802 is inserted into connectors
804 and 806, and in FIG. 8B, the connectors are brought into
sagittal alignment. In FIG. 8C, a link member 810 is fastened to
the connectors, and the tool 802 removed.
[0158] In all of the rod-receiving bodies described herein, small
apertures or slots may be provided to receive a tool for corrective
positioning and, with the aid of a specialized instrument such as
900 depicted in FIG. 9. Using such a tool, the body may be removed
from the ball-tipped hooks or pedicle screws previously described,
as appropriate. Such a tool would preferably include side portions
902 and a central pin 906 which may be forced down through the
opening 314 by handle 910, thereby applying force between the body
and hook or screw to remove the connector for repositioning or
removal.
[0159] FIG. 10 is a side-view drawing of an alternative connector
system according to the invention, wherein angled, preferably
reinforced components 1002 are fastened to pedicle screws 1004. The
members 1002 provide one or more holes, better seen in FIGS. 11 and
12, to which link members such as 1110 may be fastened. Note that
the pieces 1102 would preferably be provided in various heights and
sizes better accommodate a given patient physiology.
[0160] FIG. 11A shows one way in which the connectors introduced
with respect to FIG. 10 would be used in practice. Six connectors
such as 1102 are shown, each having four holes to receive link
bars. With this many fastening points, multiple reinforcements may
be used. In particular, both lateral and diagonal cross members are
readily accommodated. Moreover, as shown in FIG. 11B, the holes may
be used for devices other than the link members. For example,
cables 1110 may be used where appropriate, and in some cases may be
wrapped around the lamina (sublaminally) as depicted with numerical
reference 1112.
[0161] Rigid link members and cables may also be used with the
alternative connector 1202 of FIG. 12A, which includes holes 1204
on one side for link bars and additional holes 1206 on the other
side for cables. FIG. 12B shows the alternative connector of FIG.
12A in use, with a combination of cables 1216 and rigid link
members 1214 (shown as lines) being used to establish a stable,
cross-coupled structure.
[0162] FIG. 13 illustrates an alternative arrangement according to
the invention, wherein cables 1302 are applied to an existing
rod/plate system to impart further structural integrity. Four
diagonally oriented cable paths are used, though more or fewer may
be employed, depending upon the needs of the patient. In contrast
to interconnection of the cables to the rods themselves, as shown
in FIG. 13, cables 1402 may be applied to the screws 1406 binding
the rods to the vertebrae, as shown in FIG. 14.
[0163] FIGS. 15A and 15B illustrate yet a further, different
embodiment of the invention, wherein a rigid link bar 1502 is
attached to pedicle screws 1504 using nuts 1506 or other
appropriate fasteners. With a sufficiently long exposed threaded
end, multiple link members may be used in conjunction with each
pedicle screw in a stacking arrangement, thereby allowing for a
criss-crossed structural assembly, as shown in FIG. 15B.
[0164] As opposed to rigid link members of a fixed length, the
invention also anticipates the use of telescoping members,
including the type shown generally at 1700 in FIG. 17. Each end of
such a device would include a flat plate, ball, or fastener such as
1702 and 1703 appropriate to one of the connector systems disclosed
herein, but with the length being variable in telescoping or
sliding fashion. Preferably, one or more setscrews 1704 would be
used to lock the member in accordance with a desired length at any
time, including in the midst of an adjustment procedure. Any
cross-sectional geometry may be used, so long as a telescoping
action is provided. In particular, whereas a cylindrical geometry
may allow for twisting as well as extension prior to locking in
place, non-circular cross-sections may be used to permit
extension/contraction without twisting, as desired.
[0165] FIGS. 18A-18C illustrate a sublaminar connector 1800
according to the invention, having discs 1802, preferably that
swivel, to which the telescoping rods of the type shown in FIG. 17
may be adjustably attached. FIG. 18A presents one view of such a
device, showing a lower hook 1820 adapted for sublaminar
engagement. FIG. 18B shows a top-view of the device, and FIG. 18C
is a cross-sectional view, with arrows used to indicate the
preferred swivel action.
[0166] FIG. 19 is a drawing of a further alternative device 1900
having connectors 1902, which also preferably swivel, but include a
pedicle screw 1904 for fixation as opposed to a sublaminar engaging
portion, as shown in FIGS. 18A-18C. Note that although the body of
the device 1900 is depicted integrally with the pedicle screw 1904,
the body may be connected to lower screw portion through a
connector shown with broken lines at 1910.
[0167] Installation and operation of the devices of FIGS. 18 and 19
are shown in FIGS. 20 and 21, incorporating the sublaminar device
of FIG. 18, pedicle screw unit of FIG. 19, and threaded rod of FIG.
23. FIG. 20 is a lateral view of an assembly utilizing these
devices, whereas FIG. 21 is a posterior-anterior view.
[0168] A preferred way in which the telescoping rods and fixation
devices discussed above will now be described to align a problem
with curvature. In FIG. 22A, a telescoping rod 2202 is sized
relative to a pair of connectors 2204 and 2204' to be aligned, with
fasteners 2206 with nuts 2208 being provided for tightening
purposes. FIG. 22B shows the telescoping rod 2202 attached to the
connectors 2204, with the arrows being indicative of the way in
which the segments of the rod are moved to displace the connectors
prior to tightening. FIG. 22C shows how the segments of the rod are
locked onto the connectors in an extended position, enabling the
vertebrae to be distracted and aligned. It will be clear to one of
skill that, as opposed to extension, the segments of the rod 2202
may be brought together, as the case may be, to provide a desired
amount of compression.
[0169] FIG. 23 is a side-view drawing of a preferred
cross-connector 2300 according to the invention, which may be used
in conjunction with, or in place of, the extensible rods just
described. The assembly includes a threaded rod 2300, onto which
the preferably swiveling attachment mechanisms 2304, 2304' of the
connectors are journaled. On either side of the connectors, washers
such as 2306, 2306' and nuts such as 2308, 2308' are also
preferably used for a precise, yet stable alignment when
tightening.
[0170] Although the telescoping and threaded rods have thus far
been depicted as straight, they may be curved or bent for different
situations. In the case of the telescoping rod, both ends may
additionally be adjustable, as shown in FIG. 24. The connector
bodies may be attached to the rods such as 2500 in various ways,
including the use of a set screw 2502 or other fastener, as shown
in the cross-section of FIG. 25.
[0171] FIGS. 26A-26C illustrate an alternative interconnection
mechanism that may be used in conjunction with, or in place of, the
circular swivel-type connectors described above. In this case, the
connectors bodies 2602, 2602', which may feature pedicle screws or
sublaminar hooks 2608, as shown, would include one or more posts
such as 2620 extending therefrom, onto which elongated elements
2630 having closed-fork ends such as 2632, 2632' would be
journaled, adjusted, then tightened for a desired level of
alignment. Although a telescoping rod is shown, threaded
arrangements should also be apparent to those of skill, as
described above with reference to the swivel-type arrangements.
[0172] FIG. 26A shows a telescoping version of this embodiment
prior to placement onto bodies 2602, 2602'. FIG. 26B shows the
fork-shaped ends 2632, 2632' being placed onto the posts, and FIG.
26C shows the way in which the ends are tightened onto the posts,
preferably through the use of a set screw 2608 which applies
pressure to the cylindrical portion of the hook to lock it into
position. The setscrews are locked onto the connectors to avoid the
frustration of inserting the setscrew into a small space on the
hook itself. Using the arrangement of the invention, the setscrews
may be tightened or loosened, but will not be removed from the
connector and inadvertently lost. Preferably, the cylindrical
projections from the hook or pedicle screw bodies have an
enlargement at their ends to help prevent the connector from
sliding off the hook once it is tightened in place.
[0173] FIG. 27 is a top-view drawing of an alternative connector
adapted for use with any of the swivel-type embodiments described
herein, the configuration permitting variable angulation in two
additional planes. FIG. 28 is a further adaptation of the device of
FIG. 28, also providing lockable angulation with multiple degrees
of freedom.
[0174] FIGS. 29A and 29B depict an alternative connector system
according to the present invention. Broadly, the system uses a
ball-shaped connector 2902 on a rod 2904 or other member, wherein
the spherical end 2902 fits into a socket 2906 on member 2908.
Journaled over the element 2904 is a threaded nut 2910 which
engages with threads 2912 on element 2908, thereby locking the
device into a desired orientation, as shown in FIG. 29B.
[0175] FIG. 30A shows an embodiment of the invention wherein a
connector body and elongated element are integral, providing a
low-profile solution particularly for shorter interconnections.
Longitudinal member such as 3002 is incorporated into the connector
to facilitate insertion into adjacent vertebrae. As such, the
combined unit is inherently shorter. Also, note that the connector
on the middle screw 3004 is attached to the pedicle screw through a
threaded post. Once again, this shortens the unit, particularly in
areas of the spine where the attachments to the vertebrae are
farther apart and where more spinal deformity may be present.
Multiple connectors may also be used to increase the allowed
angulation between vertebrae, as shown in FIGS. 30B and 30C.
[0176] FIG. 31A shows swiveling socket-type connectors on a body
attached to a pedicle screw. FIG. 31B shows the arrangement of FIG.
31A in an assembled condition. FIG. 31C is a top view illustrating
the swiveling feature of the embodiments of FIGS. 31A and 31B. Such
swivel connectors may also be incorporated into a sublaminar hook
configuration. Hooks and sublaminar attachments do not require the
connector-connector feature, however, since devices of this type
are slid into position. FIG. 32, for example, shows a sublaminar
hook having outward projections to receive the swivel
connectors.
[0177] FIG. 33A is a drawing of a top view of a screw connector
having two posts. FIG. 33B is a top view of a screw connector
according to the invention having a single post. FIG. 33C is a top
view of a hook connector. FIG. 33D is an oblique drawing which
shows a preferred use of frictional surfaces to lock in the swivel
action upon achieving a desired orientation. The friction surface
may also be incorporated between the connectors and the screws or
hooks. FIG. 33E shows how a setscrew (or setscrews) may be added to
help control rotation of a connector according to the
invention.
[0178] The combined longitudinal member-connector unit may feature
a variety of lengths for the longitudinal members, as well as
angles between the longitudinal member and connector. FIG. 34A, for
example, shows how a combined longitudinal member and connector may
have a particular length and angle to address a particular
situation. FIG. 34B illustrates an assembled version of the angled
unit of FIG. 34A.
[0179] FIG. 35 is a series of drawings that show a variety of
longitudinal members in straight and curved configurations. The
longitudinal members shown in FIG. 35 are preferably pre-fabricated
in various sizes and shapes with the nuts attached. They are used
when the space between the attachment sites on the vertebrae are
close together. Depending upon material choice, they may be further
bent by the surgeon at the time of surgery as necessary. When the
space between the vertebrae attachment sites is larger than the
telescoping longitudinal member, a turnbuckle-like longitudinal
member would preferably be used. It will be appreciated that these
and other ball-ended configuration may incorporate the cap
configurations of FIG. 3G.
[0180] The telescoping/turnbuckle members with nuts could also be
assembled by the surgeon. For example, FIG. 36A shows how a
telescoping member may be assembled through a pair of nuts then
joined. FIG. 36B shows a joined assembled version of the assembly
of FIG. 36A.
[0181] The cross-links may also be attached to the top of the
central posts in many different configurations. FIG. 37 illustrates
a plate-like embodiment of the cross-link. This embodiment shows
only one cross-link end per connector. For more rigidity, the
cross-links could be stacked. For example, FIG. 38 shows an
embodiment with two cross-link ends per connector. The longitudinal
members and connectors are not drawn in order to better illustrate
the cross-links, which are preferably thinner than the rigid
longitudinal members in FIGS. 14 and 15. FIG. 39 is a side view of
a connector including a cross-link.
[0182] This section of the description provides details of various
connector configurations according to the invention, including
designs particularly suited to different vertebral levels. In the
accompanying drawings, the central connector bodies are threaded at
the ends where engage with the longitudinal members. As discussed
elsewhere herein, the central connectors may be threaded on either
end, though the connectors at the end of a construct are preferably
threaded on one end only. The central portion of the connector may
include a flat surface, or may be square or rectangular to
accommodate a wrench to stabilize the connector while tightening
the nut and facilitate attachment to pedicle screw. The central
portion of the connector may further include a pedicle hole to
attach the connector to a pedicle screw. A friction surface may be
provided between the connector (interior surface) and the pedicle
screw superior surface.
[0183] FIGS. 40A-40F provide different views of a central lumbar
connector according to the invention. In the lumbar region in
particular, the connectors should be as short as possible. The
pedicle screws may be 3 cm apart or closer. In this and in other
embodiments, a friction surface may be provided between the rod
ends and the connector seat. The connectors should be as small as
possible in every dimension, since prominent hardware could cause
the patient to experience pain.
[0184] FIGS. 41A-41G depict different views of a connector adapted
to the cephalad end. As shown in FIGS. 41B and 41G, in particular,
such connectors may have a special shape to avoid impingement on
the first mobile facet joint of the spine. This is perhaps better
visualized in FIGS. 58A and 58B. Note that if the inferior surface
has a friction surface left and right units may be provided.
Without a friction surface, however, the connector may be turned
over for the other side. A special wrench (not shown) may also be
provided to hold the connector while tightening the nut. The wrench
could be the female version of the non-threaded portion of the
connector attached to a handle.
[0185] The caudal end may use same connector as used in cephalad
end. A reduced profile is not necessary, and the connector is
similar in every other way to the cephalad connector. These
connectors may also be used in other positions in patients with
spinal deformities. Two connectors will preferably be used per
pedicle screw or hook. The portion of the connector that attaches
the hook or screw should be as small as possible to allow the
connector to rotate. The connector should be as strong as possible
to prevent fatigue fracture. If the connector is strong enough, it
could also be used in the lumbar spine rather than the end
connectors described above. This arrangement could reduce
manufacturing costs by using a single type of end connector.
[0186] FIGS. 42A-42E show different views of a thoracic connector
according to the invention. FIGS. 43A and 43B show exploded and
assembled views, respectively, of sublaminar hooks with thoracic
connectors attached thereto. FIGS. 44A-44C are top views showing
swiveling before and after locking into a straightened
configuration. The connectors rotate until tightening to allow for
spinal deformity. They can be loosened and retightened to provide a
desired level of correction.
[0187] FIG. 45 illustrates a pedicle screw used to discuss
different sizes and diameters according to the invention. In the
preferred embodiments, the pedicle screws feature a tapered minor
diameter. Most screws break at the connection to the rod, since the
bone near the tip of the screw is cancellous, whereas bone near the
connector end is cortical. The deeper thread near the tip and
constant major diameter for most of the screw serves to enhance
pullout strength. However, relatively blunt tips are preferred to
avoid vascular injury if the screw tip extends through the
vertebra. Generally a tap is used to provide a pathway for the
screw. The bone is soft and some surgeons avoid the tapping step.
Often a surgeon uses a tap for a 5.5 mm screw but insets a 6.5 mm
screw.
[0188] FIG. 46 is a perspective view of the pedicle screw of FIG.
45 including a ball connector and link bar. FIG. 47 is a drawing of
the configuration of FIG. 46 in an assembled state. FIG. 48 is an
assembled connector having two opposing ball-receiving sockets.
Note that pedicle screws for independent double connectors may
require a different (i.e. longer) design. FIG. 49 is a drawing of
an exploded and assembled view of a pedicle screw having
independent double connectors. FIG. 50 shows how a non-round
interconnection may be used to prevent rotation of the pedicle
screw relative to a connector body.
[0189] This invention also provides `open` pedicle screws which may
be deployed when there is not enough room at 5100 between screws to
allow connectors, as shown in FIG. 51. FIG. 52A shows such a hinged
connector in an open condition, whereas FIG. 52B shows the hinged
connector locked onto a rod. Indeed, it will be appreciated that
most, if not all, of the various embodiments described herein may,
at least in some way, be adapted for use with spinal rods of the
type now in common use.
[0190] FIGS. 53A-53M illustrate the alternative use of straps
according to the invention for rod movement and stabilization. FIG.
53A depicts a pedicle screw 5300 having lower threads 5304 and body
5302 with rod-receiving area 5306 and threads 5308 for a
compression fastener (not shown). An indentation 5310 is provided
on the side for grasping. Typically, surgeons force spinal rods
into such pedicle screws and vertebral hooks with bulky clamps and
threaded "rod pushers" as depicted schematically in FIG. 53B. This
presents significant disadvantages. For one, the clamps and rod
pushers are bulky. The large clamps and pushers also frequently
impinge on one another. To avoid impingement, surgeons often place
excessive force on a single screw or hook to allow placement of a
setscrew to hold to hold the rod in place, enabling the surgeon to
remove the clamp. The excessive force on a hook or screw can crack
the vertebra, and the bulky clamps may interfere with setscrew
placement.
[0191] The embodiment depicted in FIGS. 53D-53M uses wires, cables,
or straps to guide spinal rods into pedicle screws and hooks. The
preferred embodiment uses plastic straps or cable ties 5344 as
tightening tools. FIG. 53D shows the use of a strap piece 5340 for
such a purpose. As shown in FIGS. 53E and 53F, the strap piece 5340
is preferably rotatable beneath the body of the rod fastener. As
depicted in FIG. 53L, the straps may be removed once the rod is
held in place with setscrews or nuts.
[0192] FIG. 53G shows a cable tie 5344 engaged with the strap piece
5340 prior to tightening. FIG. 53H shows the cable tie tightened
and the rod in place within the pedicle screw. FIG. 53I shows the
alternative use of a removable strap piece 5350. FIG. 53J shows a
cable tie 5344 engaged with the strap piece 5350 prior to
tightening. FIG. 53K shows the cable tie tightened and the rod in
place within the pedicle screw. FIG. 53M shows how this and other
aspects of the invention are not limited to pedicle screws, but may
also be configured for sublaminar hooks and other devices.
[0193] The use of cable ties and straps has several advantages. The
straps are less bulky than the clamps and pushers currently in use.
Straps, with locking mechanisms, hold tension after the tightening
tool is removed. As such, the tightening tool can be removed from
the wound, giving the surgeon more room to work. Straps can be
tightened repeatedly as the rod advances into several hooks or
screws. Thus, the loads are shared by multiple spinal attachment
sites rather than a single attachment site. Vertebral fracture is
therefore less likely. The straps, cables, and wires are lateral to
the hook and screw rod connection. Accordingly, the lateral
position does not interfere with setscrew placement.
[0194] The elongated members or rods according to the invention may
also be provided in a variety of configurations, including solid-,
non-telescoping, telescoping, turnbuckle, and different lengths and
shapes. The solid rods with spherical ends may be manufactured with
the nuts in position, or half washers may be used as shown in FIGS.
56 and 57 to reduce costs. Rods with single spherical end rods may
use nuts added by the surgeon in lengths that may be cut at the
time of surgery to customize.
[0195] FIG. 54 is a side view of a turnbuckle rod according to the
invention. Preferably, such a device exhibits a contracted length
on the order of 3 cm while being expandable to 10 cm or beyond.
Many different sizes may be provided as necessary to accommodate a
greater range. FIG. 55 shows the combined use of ball-and-socket
connectors in conjunction with optional crisscross link bars. Such
bars are preferably narrow, on the order of 2 mm thick, in 2 cm-10
cm lengths with 3 mm increments.
[0196] As discussed above, the nuts may be added to solid rods
after the rods are manufactured using half- or slotted washers.
FIG. 56 shows how a half-washer 5610 may be used in conjunction
with a nut opening 5608 that is large enough to slide over the
sphere at the end of a rod. FIG. 57 shows an alternative use of a
slotted washer 5610 permitting a nut to slide over the spherical
end 5604 of a solid rod 5602.
[0197] Prior-art spinal rods, screws, and plates risk impingement
on the first mobile facet cephalad to the fusion. For example, the
inferior facet of L.sub.4 may impinge on the plate, rod, nut, or
connector extending from L.sub.5 to S.sub.1 in a L.sub.5-S.sub.1
fusion. Impingement can lead to pain, facet arthritis, facet
fracture, and additional surgery. What is needed is a reduced
profile connector to prevent impingement. FIG. 58A shows a modified
connector adapted to reduce impingement. FIG. 58B is a drawing of
an anti-impingement connector utilizing a ball-and-socket
arrangement.
[0198] FIGS. 59A and 59B are different views of a transverse
connector according to the present invention. The transverse
connector (cross brace) fits on the rods between the hooks. FIG. 60
shows the combined use of transverse connectors and hinged hooks
that lock onto a solid rod. The convex solid rod may be placed
after the modular system to restore the spine to its proper
alignment. The convex rod may include an octagonal or other
cross-section to prevent rotation of cross brace on the rod, as
shown in FIG. 61. For example, the convex rod may have longitudinal
grooves. Such features may travel the length of the rod or be
interrupted. FIG. 62A illustrates the use of a continuous shaped
rod, in this case having a grooved cross-section. FIG. 62B
illustrates how the modification along the rod may be interrupted
along its length.
[0199] FIG. 63 shows a bevel connector embodiment according to the
invention. Such a connector allows 15-20 (or more) degrees of
angulation before tightening. Although this type of connector is
used in current spine implants, prior art configurations use only
one rod on each side of spine. This embodiment of the invention
allows use of multiple rods/side as shown in FIG. 64. Indeed, it is
believed that the modular hooks and screws according to the
invention represent the only system that allows two rods to be
attached to a single rod hook or screw.
[0200] FIG. 65A shows a stabilization clamp for use with various
embodiments disclosed herein. FIG. 65B is an end of the
configuration of FIG. 65A. FIG. 66A is a different alternative
embodiment of a stabilizing assembly, and FIG. 66B is a
cross-section of the assembly of FIG. 66A.
[0201] FIGS. 67A-67C illustrate the use of lockable swivel-type
connectors 6704, 6704', which may be fastened to one or, preferably
a pair, of parallel (or non-parallel) rods 6702, 6702' to provide a
desired degree of alignment and correction. This particular
embodiment uses a modified hook structure and setscrew arrangement,
which may be moved along the rod, as shown in FIG. 67B, until a
desired degree of separation/orientation is achieved, at which
point all of the various components may be tightened into place
with fasteners 6710, 6710'.
[0202] To ensure stable interconnections that do not loosen through
movement or degrade with time, the invention may take advantage of
materials and/or geometries to enhance structural integrity. For
example, shape-memory technology may be used to assist in locking
the screws, rods, caps, joints and other components to one another.
Such interfaces may be mobile until body temperature changes the
dimensions to promote a tighter fit, where applicable. In addition,
particularly with respect to threaded fasteners, the thread sizes
may be slightly mismatched to promote a slight galling for an even
tighter fit.
[0203] While the present invention has been shown and described in
terms of preferred embodiments thereof, it should be understood
that this invention is not limited to any particular embodiment,
and that changes and modifications may be made without departing
from the true spirit and scope of the invention as defined in the
appended claims.
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