U.S. patent application number 14/315684 was filed with the patent office on 2014-12-25 for bone anchoring device and stabilization device for bone parts or vertebrae comprising such a bone anchoring device.
This patent application is currently assigned to Biedermann Technologies GmbH & Co. KG. The applicant listed for this patent is Biedermann Technologies GmbH & Co. KG. Invention is credited to Lutz Biedermann, Jurgen Harms, Wilfried Matthis.
Application Number | 20140379031 14/315684 |
Document ID | / |
Family ID | 40212895 |
Filed Date | 2014-12-25 |
United States Patent
Application |
20140379031 |
Kind Code |
A1 |
Biedermann; Lutz ; et
al. |
December 25, 2014 |
BONE ANCHORING DEVICE AND STABILIZATION DEVICE FOR BONE PARTS OR
VERTEBRAE COMPRISING SUCH A BONE ANCHORING DEVICE
Abstract
A stabilization device for bone parts or vertebrae includes two
bone anchoring devices for anchoring in the bone parts or
vertebrae. At least one of the bone anchoring devices includes an
anchoring element with an anchoring section for anchoring in a bone
part or a vertebra and a head, and a receiving part for receiving a
stabilization rod. The receiving part has a seat for receiving the
head so that the head can pivot with respect to the receiving part.
The stabilization device includes a first pressure element which is
movable in the receiving part so that it can be pressed onto the
head to lock the angular position of the head. The stabilization
device includes at least two stabilization rod sections, and at
least two guiding channels within the receiving part which have a
distance from each other for guiding through the at least two
stabilization rod sections so that the rod sections do not touch
each other.
Inventors: |
Biedermann; Lutz;
(VS-Villingen, DE) ; Harms; Jurgen; (Karlsruhe,
DE) ; Matthis; Wilfried; (Weisweil, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Biedermann Technologies GmbH & Co. KG |
Donaueschingen |
|
DE |
|
|
Assignee: |
Biedermann Technologies GmbH &
Co. KG
|
Family ID: |
40212895 |
Appl. No.: |
14/315684 |
Filed: |
June 26, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12571299 |
Sep 30, 2009 |
8795336 |
|
|
14315684 |
|
|
|
|
61103858 |
Oct 8, 2008 |
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Current U.S.
Class: |
606/266 |
Current CPC
Class: |
A61B 17/7032 20130101;
A61B 17/702 20130101; A61B 17/7046 20130101; A61B 2017/00845
20130101; A61B 17/7035 20130101; A61B 17/7049 20130101; A61B
17/7037 20130101 |
Class at
Publication: |
606/266 |
International
Class: |
A61B 17/70 20060101
A61B017/70 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 8, 2008 |
EP |
08 017 644.9 |
Claims
1-28. (canceled)
29. A polyaxial bone anchoring device comprising: an anchoring
element comprising a shank for anchoring a bone part or a vertebra
and a head; a receiving part configured to pivotably receive the
head, the receiving part having a first end, a second end opposite
to the first end, a coaxial bore, a first recess and a second
recess each adjacent to the first end for receiving a rod, and a
central axis extending through the first end and the second end,
the receiving part comprising two legs separated by the coaxial
bore and the first and second recesses, a longitudinal axis of the
recesses being substantially perpendicular to the central axis; a
first clamping part having a rod supporting surface that extends
from the coaxial bore into the first recess when assembled in the
receiving part; a second clamping part configured to exert pressure
on the rod when the rod is in the coaxial bore; and a locking
device configured to exert pressure on the second clamping part to
secure the rod in the coaxial bore; wherein, when the bone
anchoring device is assembled, the first clamping part is located
between the head of the anchoring element and the second clamping
part.
30. The polyaxial bone anchoring device of claim 29, wherein the
rod supporting surface has a longitudinal axis perpendicular to the
central axis.
31. The polyaxial bone anchoring device of claim 29, wherein the
first clamping part further comprises a coaxial bore that is
coaxial to the central axis.
32. The polyaxial bone anchoring device of claim 29, wherein rod
supporting surface of the first clamping part extends from the
coaxial bore of the receiving part into the second recess.
33. The polyaxial bone anchoring device of claim 32, wherein the
second clamping part extends from the coaxial bore of the receiving
part into the first recess and into the second recess.
34. The polyaxial bone anchoring device of claim 29, wherein the
second clamping part has a rod facing surface having a longitudinal
axis perpendicular to the central axis.
35. The polyaxial bone anchoring device of claim 29, wherein
respective free ends of the first clamping part and the second
clamping part extend into the first recess such that the free ends
are flush with an outer surface of the receiving part.
36. The polyaxial bone anchoring device of claim 29, wherein the
second clamping part is configured to be rotatably coupled to the
locking device.
37. The polyaxial bone anchoring device of claim 29, wherein the
first clamping part further comprises a first portion that is
configured to exert pressure on the head.
38. The polyaxial bone anchoring device of claim 37, wherein the
first portion has a recess at a side opposite to the rod supporting
surface and the recess is configured to accommodate a portion of
the head.
39. A spinal stabilization system comprising at least two polyaxial
bone anchoring devices according to claim 29 and a rod, wherein the
rod comprises a nickel-titanium alloy.
40. The polyaxial bone anchoring device of claim 37, wherein the
first portion has a cylindrical outer surface configured to be
received in the coaxial bore and a spherical inner surface
configured to engage the head.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] The present application is a continuation of U.S. patent
application Ser. No. 12/571,299, filed Sep. 30, 2009, which claims
the benefit of U.S. Provisional Patent Application Ser. No.
61/103,858, filed Oct. 8, 2008, the contents of which are hereby
incorporated by reference in their entirety, and claims priority
from European Patent Application No. 08 017 644.9, filed Oct. 8,
2008, the contents of which are hereby incorporated by reference in
their entirety.
BACKGROUND
[0002] The invention relates to a bone anchoring device, in
particular to a polyaxial bone screw which is connected to two
stabilization rods and to a stabilization device having such a bone
anchoring device, in particular for the stabilization of the spinal
column.
[0003] A dynamic stabilization device for bones, in particular for
vertebrae, is described in US 2004/0049190 A1. The stabilization
device includes two bone anchoring elements, at least one of which
is a polyaxial bone screw and a rigid rod with a longitudinal axis
connecting them. An elastic element is inserted between the two
bone anchoring elements. The elastic element acts on the bone
anchoring elements to exert a force in a direction of the
longitudinal axis. One of the bone anchoring elements is fixedly
connected to the rod to prevent translational movement of the rod
and the other bone anchoring element is slidably connected to the
rod.
[0004] EP 1 800 614 A 1 describes a dynamic stabilization device
for bones or for vertebrae having at least two bone anchoring
elements and at least one connection element in the form of an
elastic loop connecting the bone anchoring elements. In one
embodiment, the bone anchoring element is in the form of a
polyaxial bone screw having a receiving part which accommodates to
two elastic loops each of which can be connected to a second bone
anchoring element.
[0005] Based on the foregoing, there is a need to provide a bone
anchoring device and a stabilization device comprising such a bone
anchoring device which allows the dynamic stabilization of bone
parts or vertebrae and which allows a variable design of elastic
properties of the dynamic stabilization device.
SUMMARY
[0006] The provision of a modular double-rod, i.e. two rods, allows
to design the bone anchoring device more compact in terms of the
height of the bone anchoring device, since each rod can be designed
smaller than a single rod. The low profile cross-section of two
rods compared to one single rod has also the advantage that the
stiffness of the rods is enhanced. The stability in view of bending
or torsional loads of the double-rod system is also enhanced.
[0007] The dynamic properties of the stabilization device can be
adjusted by selecting appropriate rods and/or adjusting the sliding
motion of the rods by stops and/or dampening elements. The dynamic
properties of the rods can vary. For example the rods can have the
same or different elastic properties. They can be made of the same
or different material.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 shows a perspective side view of the stabilization
device.
[0009] FIG. 2 shows a perspective exploded view of the
stabilization device.
[0010] FIG. 3 shows an exploded view of the bone anchoring device
according to a first embodiment.
[0011] FIG. 4 shows a perspective view of the bone anchoring device
of FIG. 3 in an assembled state.
[0012] FIG. 5 shows a perspective view from the side of the first
pressure element in a first embodiment.
[0013] FIG. 6 shows a perspective view of the second pressure
element in a first embodiment.
[0014] FIG. 7 shows a partially sectional view of the bone
anchoring device with the first and second pressure element
according to the first embodiment.
[0015] FIG. 8 shows a partially sectional view of the bone
anchoring device with the first and second pressure element
according to a second embodiment.
[0016] FIG. 9 shows an exploded perspective view of the bone
anchoring device with a first and second pressure element according
to a third embodiment.
[0017] FIG. 10 shows a perspective view of the bone anchoring
device of FIG. 9 in an assembled state.
[0018] FIG. 11 shows a perspective view of a rod according to
another embodiment.
DETAILED DESCRIPTION
[0019] The invention is now described in detail with reference to
the embodiment of the stabilization device shown in FIGS. 1 to 8.
The stabilization device includes a first polyaxial pedicle screw
1, a second pedicle screw 2 and two rods 3a, 3b connecting them for
stabilizing two adjacent vertebrae. The two rods 3a, 3b may be
separate rods as shown in FIG. 2. Alternatively, as shown in FIG.
11, the rods 3a, 3b may be connected or formed in one-piece to
define a single rod 3.
[0020] On each rod a spring element 4a, 4b is provided and the rods
3a, 3b are connected by rod connectors 5, 6. The rods 3a, 3b are
fixedly clamped in the second pedicle screw 2 and can slide through
the first pedicle screw 1 as shown by the arrows. The sliding
motion is limited by means of the rod connector 6 which connects
the free ends of the rods 3a, 3b and acts as a stop. The springs
4a, 4b and the rod connector 5 limit the sliding motion of the rods
3a, 3b relative to the first pedicle screw 1 in the direction of
the second pedicle screw 2. The springs provide elastic dampening.
The rod connectors 5, 6 are sleeve shaped with two channels 5a, 5b,
6a, 6b, respectively, for guiding through the rods 3a, 3b. The
distance of the channels corresponds to the distance of the rods in
which they are guided through the pedicle screws. The rod
connectors 5, 6 connect the rod 3a, 3b by means of a press-fit
connection i.e the diameter of the channels is selected such that
the rods are firmly connected. The rod connectors 5, 6 can be made
of an elastomer material or any other body compatible material.
[0021] The springs 4a, 4b in this embodiment are shown as helical
springs encompassing the rods 3a, 3b like sleeves. They can be made
of any body compatible material, in particular of titanium, nickel
titanium alloys, for example nitinol, or other materials.
[0022] The rods 3a, 3b exhibit a flexibility under forces having a
component perpendicular to the rod axis, such as bending forces.
For this purpose the rods are made of non-compressible materials,
such as stainless steel, titanium, nickel titanium alloys, such as
nitinol, PEEK or carbon reinforced PEEK or other body compatible
materials.
[0023] It should be noted that the rod connectors and the springs
are only examples for the function of connecting the two rods,
providing a stop and providing a dampening to the sliding
motion.
[0024] Next, the first pedicle screw 1 will be described in detail
with reference to FIGS. 3 to 7. The pedicle screw 1 comprises a
screw element 10 with a threaded shank 11 and a spherically
segment-shaped head 12. At the free end of the head 12 a recess 13
is provided for engagement with a tool. The pedicle screw 1 further
comprises a receiving part 20 with a first end 21 and a second 22
and a coaxial bore 23 extending from the first end in the direction
of the second end. At the second end 22 the bore 23 tapers to
provide an opening and a seat 24 for the screw head 12 as shown in
particular in FIG. 7.
[0025] The receiving part 20 further comprises a recess 25
extending from the first end 21 in the direction of the second end
22 which provides a channel through the receiving part in a
direction perpendicular to the bore axis of bore 23 for guiding
through the rods 3a, 3b. The recess provides two free legs 26a,
26b. Near the first end 21 the free legs 26a, 26b have an internal
thread 27 for cooperation with a fixation screw 30. The screw
element 10 and the receiving part 20 as well as the fixation screw
30 are made of a rigid body compatible material, such as a body
compatible metal like stainless steel or titanium or a titanium
alloy, such as nitinol.
[0026] For locking the head 12 and in consequence the angular
position of the screw element 10 within the seat 24 of the
receiving 20 a first pressure element 40 and a second pressure
element 50 are provided. The first pressure element 40 and the
second pressure element 50 also form guiding elements for guiding
the rods 3a, 3b through the receiving part 20. The first pressure
element 40 has a substantially cylindrical body part 41 which is
sized such that the first pressure element 40 can be inserted in
the receiving part and moved in an axial direction within the bore
23. At its side facing the head 12 of the screw element the first
pressure element 40 comprises a cylindrical recess 42 shown in FIG.
7 in which a cylindrical insert 43 is provided. The insert 43 has
on its side facing the head 12 of the screw element a spherical
recess 44 the radius of which fits to the radius of spherical head
12 of the screw element.
[0027] The first pressure element 40 further comprises a cuboid
body part 45 which is shaped so as to fit in the recess 25 of the
receiving part 20 as shown in particular in FIGS. 3 and 4. The
width of the body part 45 corresponds to the width of the recess 25
and the length is selected such that the first pressure element is
flush with the outer surface 28 of the receiving part 20 as shown
in FIG. 4. On its side opposite to the recess 42 the cuboid body
part includes two cylinder segment-shaped recesses 46a, 46b the
cylinder radius of which is slightly larger than the radius of the
rods 3a, 3b. The recesses 46a, 46b extend perpendicular to the axis
of the coaxial bore 23 of the receiving part 20. The recesses
46a,46b form channels for receiving the rods 3a, 3b. Since the
recesses 46a, 46b are spaced apart from each other a rib 47 is
formed between them. The depth of the recesses 46a, 46b is
preferably slightly larger than the radius of the rods 3a, 3b. The
first pressure element 40 also has a coaxial bore 48 for providing
access to the head 12 of the screw element with a tool. Similarly,
the cylindrical insert 43 has a coaxial bore 49. The cylindrical
body part 41 and the cuboid body part 25 are shown to be made in
one piece so that cylindrical segment-shaped flanges 41a, 41b are
provided on each side of the channel 46a, 46b. The flanges
facilitate the guidance of the first pressure element 40 within the
receiving part 20. The cuboid body part 45 prevents rotation of the
first pressure element within the receiving part once the first
pressure element is inserted into the recess 25.
[0028] The second pressure element 50 is substantially cuboid
shaped with a width and length corresponding to that of the cuboid
body part 45 of the first pressure element 40. Therefore, it also
fits into the recess 25 of the receiving part. On its long sides it
comprises two cylindrical segment-shaped flanges 51a, 51b
corresponding to the flanges 41a, 41b of the first pressure
element. On its side opposite to the first pressure element 40, the
second pressure element 50 comprises a cylindrical recess 52 and a
coaxial cylindrical projection 53 in which a corresponding
ring-shaped projection 31 and a cylindrical recess 32 of the
fixation screw 30 engage, as shown in FIG. 7. Thereby, the fixation
screw 30 can be rotatably connected to the pressure element 50.
[0029] On its side facing the first pressure element, the second
pressure element 50 comprises two longitudinal cylinder
segment-shaped recesses 56a, 56b which are complementary in their
size and distance to the channels 46a, 46b of the first pressure
element. The channels 56a, 56b are spaced apart by a rib 57.
[0030] In the assembled state shown in FIG. 7 the first pressure
element presses via the insert 43 onto the head 12. The second
pressure element 50 presses onto the first pressure element 40
thereby providing closed channels for the rods 3a, 3b which are
accommodated therein with a gap 60 to the wall of the channel.
Since the fixation screw 30 is rotatably connected to the second
pressure element, the fixation screw 30 can be tightened when the
second pressure element 50 is inserted.
[0031] The first pressure element and the second pressure element
can be made of a material which facilitates sliding of the rods 3a,
3b. For example, the pressure elements can be made of titanium or a
nickel titanium alloy which is coated or of PEEK or carbon
reinforced PEEK. The insert 43 is preferably made of the same
material as the head 12 of the screw, for example of a body
compatible metal. Instead of providing the insert 43 the first
pressure element itself can have a spherical recess to press onto
the head. Instead of providing the first and second pressure
element of a material which facilitates sliding or which is coated
or treated to facilitate sliding, the rods 3a, 3b themselves can
have a surface which facilitates sliding, for example a coated or
otherwise treated surface.
[0032] The second pedicle screw 2 shown in FIGS. 1, 2 and 8 differs
from the first pedicle screw 1 in the design of the first and
second pressure elements. All other parts are identical and have
the same reference numerals. Therefore, the description thereof is
not repeated. The shape of the first pressure element 40' and of
the second pressure element 50' of the second pedicle screw 2 is
the same as that of the first pressure element 40 and the second
pressure element 50 of the first pedicle screw 1. However, the size
of the channels 46a', 46b', 56a', 56b' is smaller than that of the
channels of the first and second pressure element of the first
pedicle screw. The radius of the channels is adapted to the radius
of the rods 3a, 3b and depth of the channels is smaller than the
radius of the rods 3a, 3b such that, as shown in FIG. 8, in the
assembled state the rods 3a, 3b are clamped between the first
pressure element 40' and the second pressure element 50'.
[0033] A second embodiment of the stabilization device is shown in
FIGS. 9 and 10 without the rods. The second embodiment differs from
the first embodiment described with reference to FIGS. 1 to 8 only
in the shape of the first and second pressure elements 400, 500.
The length of the channels 460a, 460b is smaller than the diameter
of the cylindrical body part 410. Therefore, the first pressure
element 400 and the second pressure element 500 are arranged
completely within the cylindrical bore 23 of the receiving
part.
[0034] Modifications of the above described embodiments are
conceivable. For example, the pedicle screws and the design of the
pressure elements can be such that more than two rods can be
accommodated. It is possible to use rods with different elastic
properties. It is sufficient, if one of the pressure elements has
the channels for guiding the rods, however, it is advantageous if
the rods are guided from below and from the top by the channels.
The shape of the lower part of the first pressure element can be
flat, however, a shape adapted to the shape of the head of the
screw 12 is advantageous for distributing the pressure onto the
head.
[0035] The fixation element can be a two-part fixation screw
wherein the first screw element of a bushing type presses onto the
first pressure element for locking of the head 12 and a second
screw element of a set screw type arranged within the first screw
element presses onto the second pressure element for fixation of
the rods in the embodiment shown in FIG. 8.
[0036] The receiving part can be shaped as a top loader as shown in
the figures or a bottom loader in which the screw element 10 is
introduced from the bottom, i.e. the second end of the receiving
part.
[0037] The shank of the screw element does not have to have a
thread. It can be in the form of a hook, a nail or can have barb
elements for anchoring in the bone.
[0038] The springs can be also provided adjacent the outer stop 6.
It is also conceivable that the rods themselves have an axial
elastic spring portion.
[0039] In use, first the screw elements of the pedicle screws 1, 2
which have been inserted into the receiving parts 20 are screwed
into adjacent vertebrae. The first pressure elements can be
preassembled so that after alignment of the receiving parts the
rods 3a, 3b can be inserted into the receiving parts and the
channels of the first pressure element, respectively. The rods 3a,
3b with the stops and the springs can be preassembled as well and
can be inserted as a double-rod system. For specific clinical
applications the first pedicle screw and the stop 6 points in the
direction the patient's head. However, the arrangement of the
pedicle screws depends on the specific clinical situation.
[0040] Next, after the receiving parts and the rods are aligned the
angular position of the screw elements relative to the receiving
parts is fixed by inserting the fixation screw together with the
second pressure element and tightening the fixation screw. In the
case of the second pedicle screw 2 as shown in FIGS. 1, 2 and 8 the
rods 3a, 3b are fixed simultaneously with the screw head 12. In the
case of the first pedicle screw only the head 12 of the screw
element is fixed while the rods can still slide within the
channels.
[0041] As shown in FIG. 1 the rods can slide through the receiving
part of the first pedicle screw during flexion or extension of the
spinal motion segment, whereby the sliding movement is limited by
the rod connectors 6 and 5 acting as stops and dampened by the
springs 4a, 4b. Simultaneously, the rods may experience bending
forces and can bend to some extend provided by the flexibility of
the material of the rods.
* * * * *