U.S. patent application number 14/197017 was filed with the patent office on 2014-10-02 for bone anchoring device.
The applicant listed for this patent is Biedermann Technologies GmbH & Co. KG. Invention is credited to Lutz Biedermann, Wilfried Matthis.
Application Number | 20140296920 14/197017 |
Document ID | / |
Family ID | 37796494 |
Filed Date | 2014-10-02 |
United States Patent
Application |
20140296920 |
Kind Code |
A1 |
Biedermann; Lutz ; et
al. |
October 2, 2014 |
BONE ANCHORING DEVICE
Abstract
A bone anchoring device includes an anchoring element with a
shank to be anchored in a bone or a vertebra and a head. The
anchoring device also includes a receiving portion with a first end
and a second end opposite to the first end, a longitudinal axis
passing through the two ends, a bore coaxial with the longitudinal
axis, and a first region adjacent to the second end for receiving a
section of said head. The anchoring device further includes an
element which exerts pressure on said head to lock said head in the
receiving portion. The receiving portion and the anchoring element
are connected such that the longitudinal axis of the receiving
portion and the shank axis have a fixed angle relative to each
other. Additionally, the receiving portion and the shank are
rotatable with respect to each other around the longitudinal axis
and are locked in the rotational position when pressure is exerted
on the head.
Inventors: |
Biedermann; Lutz;
(VS-Villingen, DE) ; Matthis; Wilfried; (Weisweil,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Biedermann Technologies GmbH & Co. KG |
Donaueschingen |
|
DE |
|
|
Family ID: |
37796494 |
Appl. No.: |
14/197017 |
Filed: |
March 4, 2014 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
11498931 |
Aug 3, 2006 |
8696712 |
|
|
14197017 |
|
|
|
|
60704992 |
Aug 3, 2005 |
|
|
|
Current U.S.
Class: |
606/278 ;
606/279 |
Current CPC
Class: |
A61B 17/8685 20130101;
A61B 17/86 20130101; A61B 17/7032 20130101; A61B 2017/564
20130101 |
Class at
Publication: |
606/278 ;
606/279 |
International
Class: |
A61B 17/70 20060101
A61B017/70 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 3, 2005 |
EP |
05016901 |
Claims
1. A bone anchoring device comprising an anchoring element
comprising a shank to be anchored in a bone or a vertebra and
having a shank axis, and a head; a receiving portion comprising a
first end and a second end opposite to the first end, a
longitudinal axis passing through the two ends, a bore coaxial with
the longitudinal axis, and a first region adjacent to the second
end for receiving a section of said head; an element which exerts
pressure on said head to lock said head in the receiving portion;
wherein the receiving portion and the anchoring element are
connected such that the longitudinal axis of the receiving portion
and the shank axis have a fixed angle relative to each other; and
wherein the receiving portion and the shank are rotatable with
respect to each other around the longitudinal axis and are locked
in the rotational position when pressure is exerted on the
head.
2. The bone anchoring device of claim 1, wherein said shank and
said head are separate parts.
3. The bone anchoring device of claim 1, wherein said head has an
exterior surface with a cylindrical portion.
4. The bone anchoring device of claim 3, wherein said head has a
portion which elastically clamps said shaft when pressure is
exerted on the head.
5. The bone anchoring device of claim 1, wherein the head has a
first end and a second end and a cylindrical recess extending from
the first end in the direction of the second end to receive a
rod.
6. The bone anchoring device of claim 1, wherein the head has a
hollow interior portion to receive the shank.
7. The bone anchoring device of claim 6, wherein the head has a
first end and a second end and a portion to clamp the shank tapers
towards the second end.
8. The bone anchoring device of claim 7, wherein the portion to
clamp the shank is spherically-shaped.
9. The bone anchoring device of claim 7, wherein the portion to
clamp the shank is conically-shaped.
10. The bone anchoring device of claim 7, wherein the portion to
clamp the shank comprises at least one slit.
11. The bone anchoring device of claim 1, wherein said first region
of the receiving portion for receiving the head tapers towards the
second end.
12. The bone anchoring device of claim 1, wherein the longitudinal
axis of the receiving portion and the shank axis are coaxial.
13. The bone anchoring device of claim 1, wherein said shank and
said head are formed as a single piece.
14. The bone anchoring device of claim 13, wherein said head has a
flat end surface.
15. The bone anchoring device of claim 1, wherein the element
directly exerts pressure on said head.
16. The bone anchoring device of claim 1, wherein the element
indirectly exerts pressure on said head.
17. A bone anchoring device comprising: an anchoring element
comprising a shank to be anchored in a bone or a vertebra and
having a shank axis, and a head; a receiving portion comprising a
first end and a second end opposite to the first end, a
longitudinal axis passing through the two ends, a bore coaxial with
the longitudinal axis, a first region adjacent to the second end
for receiving a section of said head, and a U-shaped recess
disposed at the first end and extending in the direction of the
second end; an element which exerts pressure on said head to lock
said head in the receiving portion; wherein the receiving portion
and the anchoring element are connected such that the longitudinal
axis of the receiving portion and the shank axis have a fixed angle
relative to each other; wherein the receiving portion and the shank
are rotatable with respect to each other around the longitudinal
axis and are locked in the rotational position when pressure is
exerted on the head; and wherein said shank and said head are
separate parts.
18. The bone anchoring device of claim 17, wherein the element
directly exerts pressure on said head.
19. The bone anchoring device of claim 17, wherein the element
indirectly exerts pressure on said head.
20. A method of using a bone anchoring device comprising: attaching
a bone anchoring element and a receiving portion to a bone or a
vertebra, the attaching comprising attaching a shank of the bone
anchoring element to the bone or the vertebra, connecting a head of
the bone anchoring element to the shank and connecting the head to
the receiving portion; rotating the receiving portion about a
longitudinal axis of the receiving portion relative to the shank;
inserting a rod in a recess of the head after aligning the recess
of the head with a recess of the receiving portion upon rotating
the receiving portion about the longitudinal axis of the receiving
portion; and fixing the rod in the receiving portion with a
fastening element, wherein fixing the rod in the receiving portion
fixes the shank and the receiving portion.
21. The method of claim 20, wherein attaching the bone anchoring
element and the receiving portion to a bone or a vertebra
comprises: instering the shank into a bore of the head from a
second end of the head, wherein an end portion of the shank is
frictionally held in the bore of the head proximate to a first end
of the head; connecting the head and the shank to the receiving
portion, the connecting comprising inserting the head and the shank
into an opening of the receiving portion, wherein the head rests
against an edge of the opening; and attaching the shank to a bone
or a vertebra.
22. The method of claim 20, wherein attaching the bone anchoring
element and the receiving portion to a bone or a vertebra
comprises: attaching the shank to a bone or verterbra, wherein an
end portion of the shank is exposed; inserting the head into an
opening of the receiving portion, wherein the head rests against an
edge of the opening; and connecting the receiving portion and the
head to the end portion of the shank, the connecting comprising
pressing the end portion of the shank inside a bore of the head,
and wherein the end portion of the shank is frictionally held in
the head.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 11/498,931, filed Aug. 3, 2006, which claims
priority from U.S. Provisional Patent Application Ser. No.
60/704,992, filed Aug. 3, 2005, and claims priority from European
Patent Application EP05016901, filed Aug. 3, 2005, the entire
disclosures of which are incorporated herein by reference.
BACKGROUND
[0002] The present disclosure relates to a bone anchoring
device.
[0003] A bone anchoring device comprising a shank to be anchored in
a bone and a receiving portion to connect the shank with a rod,
wherein the receiving portion and the shank are formed as a single
piece is known, for example, from U.S. Pat. No. 5,005,562 or from
DE 101 57 969 C1. At the time of screwing in such a so-called
monoaxial bone screw the receiving portion is aligned to receive
the rod by rotating the shank within its fixation in the bone. The
depth into which the shank can be screwed into the bone, depends on
the required orientation of the receiving portion relative to the
rod. Therefore, the possibility of fine-adjusting the orientation
of the receiving portion relative to the rod depends on the thread
pitch of the threaded shank. Usually monoaxial bone screws can not
be screwed-in to be fully seated within the anatomical
dimensions.
[0004] A polyaxial bone anchoring device, wherein the shank and the
head are separate parts, is known from U.S. Pat. No. 6,835,196 E2.
This bone anchoring device comprises a shank to be anchored in the
bone and a head which has an exterior surface with a spherical
segment-shaped portion, a receiving portion to receive said head
and an element which exerts pressure on said head. The shank is
received in a bore in the head which has a spring-yielding edge to
clamp said end portion of the shank when pressure is exerted on the
head. Since the head has an exterior surface with a spherical
segment-shaped portion, the head can be pivoted in the receiving
portion as long as a pressure is not exerted onto the head. With
this bone anchoring device it is possible to first screw in the
shank, adjust the length of the shank, if necessary, and then
connect it with the receiving portion containing the head.
[0005] For certain clinical applications monoaxial bone screws are
more appropriate than polyaxial bone screws. However, the known
monoaxial bone screws have the disadvantage that there is only a
small possibility of alignment of the receiving portion relative to
the rod and yet be fully seated in the bone so as to be flush with
the bone surface.
[0006] In view of the above, there is a need for a bone anchoring
device that can remedy one or more of the above described problems
associated with current bone anchoring devices.
SUMMARY
[0007] A bone anchoring device in accordance with the present
disclosure includes an anchoring element which has a shank to be
anchored in a bone and a head, a receiving portion to receive said
head and an element which exerts pressure on said head, wherein
said head and said receiving portion are connected such that a
longitudinal axis of the receiving portion and the shank axis have
a fixed angle relative to each other and wherein the receiving
portion and the head are rotatable relative to each other.
[0008] In accordance with the present disclosure, a bone anchoring
device of the monoaxial type provides an improved possibility of
alignment of the receiving portion relative to the rod and yet be
fully seated in the bone so as to be flush with the bone surface.
Further, the bone anchoring device includes a simple construction
and shall be easy to handle.
[0009] The bone anchoring device according to the present
disclosure has a receiving portion that is easily adjustable
relative to the rod in a range of 360.degree. around the shaft axis
independently from the depth to which the shank is screwed into the
bone. The alignment is independent from the thread pitch of a bone
thread provided at the shank. Therefore, the shank can be screwed
into the bone to be fully seated therein so as to be flush with the
bone surface.
[0010] The bone anchoring device according to the present
disclosure provides a bone scew thread with a greater thread pitch
compared to the conventional monoaxial bone screws or can provide a
bone screw with multiple-threads.
[0011] With a bone anchoring device according to the present
disclosure, it is possible to use the receiving portion and the
shank of known polyaxial bone anchoring devices, such as disclosed
in U.S. Pat. No. 6,835,196 B2 by simply combining it with the head
according to the present disclosure to provide for a monoaxial bone
screw.
[0012] Further features and advantages of the present disclosure
will become apparent from the description of embodiments in
conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 shows a cross-sectional view of the bone anchoring
device according to a first embodiment of the present
disclosure.
[0014] FIG. 2 shows an exploded view of the bone anchoring device
according to FIG. 1.
[0015] FIG. 3 shows a perspective view of the head of the bone
anchoring element, which is part of the bone anchoring device
according to FIG. 1.
[0016] FIG. 4 shows a cross-sectional view of the bone anchoring
device according to a second embodiment of the present
disclosure.
[0017] FIG. 5 shows an exploded view of the bone anchoring device
according to FIG. 4.
[0018] FIG. 6 shows a perspective view of the head of the bone
anchoring element which is part of the bone anchoring device
according to FIG. 4.
[0019] FIG. 7 shows a cross-sectional view of the bone anchoring
device according to a third embodiment.
DETAILED DESCRIPTION
[0020] As shown in FIGS. 1 to 3, the bone anchoring device includes
a receiving portion 1, which is substantially cylindrical and has a
first end 2 and a second end 3 opposite to the first end. The two
ends are perpendicular to a longitudinal axis 4. Coaxially with the
longitudinal axis 4 a bore 5 is provided which extends from the
first end 2 to a predetermined distance from the second end 3. At
the second end 3 an opening 6 is provided, the diameter of which is
smaller than the diameter of the bore 5. The coaxial bore 5 tapers
towards the opening 6 in form of a spherically-shaped section
7.
[0021] The receiving portion 1 further has a U-shaped recess 8
which starts at the first end 2 and extends in the direction of the
second end 3 to a predetermined distance from the second end 3. By
means of the U-shaped recess, two free legs 9, 10 are formed ending
towards the first end 2. Adjacent to the first end 2 the receiving
portion 1 includes an internal thread 11 at the legs 9, 10.
[0022] The bone anchoring element 13 includes a shank 14 with a
bone thread 15 and a head 16, which is formed as a separate part
and which is connected to the shank in the assembled state shown in
FIG. 1. The shank 14 has a shank axis 14a and includes a
cylindrical end portion 17 to be received in the head 16 and a tip
18 on the opposite end. The cylindrical end portion is provided
with a chamfer 17a to facilitate insertion into the head 16. At its
end surface, the end portion includes a recess 12 for engagement
with a screwing-in tool.
[0023] The head 16 is substantially cylindrically shaped and
includes a first end 19 and a second end 20 opposite to the first
end. As can be seen in particular in FIG. 3 the head 16 has a first
portion 21 adjacent to the first end 19, having a cylindrical outer
surface. The diameter of the first portion 21 is just as large that
the head 16 can slide in the bore 5. Adjacent to the first portion
21, there is a second portion 22, in which the outer surface of the
head 16 tapers towards the second end 20. In this embodiment, the
second portion 22 has a spherical segment-shaped outer surface. The
radius of the spherical segment corresponds to the radius of the
spherical section 7 of the receiving portion 1 such that the head
16 rests with its second portion 22 or a part thereof in the
spherical portion of the receiving portion 1. As can be seen in
particular in FIG. 1, the head 16 further includes a first coaxial
bore 23 extending from the second end 20 in direction to the first
end 19. The diameter of the first coaxial bore 23 is just as large
that the end portion 17 of the shank can be inserted into the bore
from the second end 20. A second coaxial bore 24 is provided which
extends from the end of the first bore 23 to the first end 19. The
diameter of the second coaxial bore 24 is smaller than the diameter
of the first coaxial bore 23 such that at the transition of the
first bore 23 to the second bore 24 a circular abutment surface 25
is provided which forms a stop for the end portion 17 of the shank
when the end portion 17 is inserted into the first coaxial bore 23
of the head 16.
[0024] In the second portion 22 of the head a plurality of slits 26
are provided which are open towards the second end 20 and extend
through the second portion 22 to a predetermined distance from the
second end 20. In the embodiment shown in FIG. 3 six slits 26 are
provided which are spaced equidistantly in a circumferential
direction. However, fewer or more slits can be provided. At least
one slit is required to render the second portion elastic to clamp
the end portion 17 of the shank. The second bore 24 allows for
accessing the recess 12 provided at the end surface of the end
portion 17 of the shank for screwing-in the shank into the bone
with a screwing-in tool.
[0025] The head 16 further includes a cylindrical segment-shaped
recess 27 starting at the first end 19 and extending in the
direction to the second end 20. The cylinder axis of the recess 27
is perpendicular to the longitudinal axis 4. The radius of the
recess 27 corresponds to the radius of a rod 28 to be received in
the recess 27. The size of the recess 27 is such that when the rod
28 is inserted, it protrudes over the first end 19.
[0026] The bone anchoring device further includes an inner screw
30, which can be screwed-in between the legs 9, 10 to fix the rod
28 and to exert a pressure via the rod 28 on the head 16. The
internal thread 11 and the cooperating thread of the inner screw 30
can have any known thread shape. A flat thread or a negative angle
thread however, has the advantage that a splaying of the legs 9, 10
does not occur which makes it unnecessary to use an outer nut or a
ring.
[0027] The length of the head 16 is such that in an assembled state
shown in FIG. 1 the head 16 encompasses the end portion 17 of the
shank with the spherical segment-shaped second portion 22 and a
part of the cylindrical portion 21.
[0028] The parts of the bone anchoring device described above are
preferably made of a body compatible material, such as for example,
titanium.
[0029] In a first mode of operation, a shank 14 of suitable length
and with a desired bone thread 15 is selected and connected with
its end portion 17 to the head 16 by introducing it from the second
end 20 of the head 16 into the first bore 23 until the end surface
abuts to the abutment surface 25. The introduction of the end
portion 17 into the head 16 from the second side 20 is facilitated
by the chamfer 17a. The end portion 17 is provisionally held in the
head 16 by means of friction.
[0030] Then, the bone anchoring element 13 consisting of the shank
14 with the mounted head 16 is introduced into the receiving
portion 1 from the first end 2 with the threaded shank 14 being
guided through the opening 6 of the receiving portion until the
head 16 rests against the edge of the opening 6. The head and the
shank are rotated such that the recess 27 of the head is aligned
with the U-shaped recess 8 of the receiving portion. In such a
preassembled state which can be loosely held by crimp bores 31
shown in FIG. 1, the shank is screwed into the bone with a
screwing-in tool which engages the recess 12 in the end portion 17
through the second bore 24 in the head. The shank 14 can be fully
screwed into the pre-drilled core hole without the necessity of
alignment of the receiving portion during the screwing-in
procedure.
[0031] When the shank is fully screwed-in, the receiving portion
together with the head can be rotated around the longitudinal axis
4 by 360.degree. to align it with respect to the rod 28 to be
inserted. After aligning the receiving portion 1 the rod 28 is
inserted until it rests in the cylindrical recess 27 of the head.
Then the inner screw 30 is inserted and tightened until it presses
onto the rod 28 which itself presses the head 16 against the
spherical portion 7 of the receiving portion. By pressing the head
16 against the spherical section 7 of the receiving portion the
spherical portion 22 of the head is compressed due to the slits 26
and firmly clamps the shank. At the same time, the head is pressed
against the spherical portion 7 and locked relative to the
receiving portion 1 in its rotational position.
[0032] In a second mode of operation, the threaded shank 14 is
first screwed into the bone or into a vertebra. Then, the receiving
portion 1 together with the loosely preassembled head 16 is pressed
onto the end portion 17 of the shark projecting out of the bone.
Thereafter, the receiving portion 1 is aligned such as to be able
to receive the rod 28. Then the inner screw 30 is screwed-in to fix
to the head and the rod.
[0033] With the bone anchoring device it is possible to use a shank
14 with a bone thread 15 having a larger thread pitch than
conventional monoaxial bone screws. Also the use of
multiple-threads for the bone thread is possible. Since the
receiving portion can be rotated by 360.degree. around the shaft
axis, the shaft can be screwed-in to the maximum depth in the core
hole.
[0034] It is further possible to use the receiving portion of
conventional polyaxial bone screws together with the head and shank
of this embodiment.
[0035] In the second embodiment shown in FIGS. 4 to 6, parts which
are identical to the first embodiment are provided with the same
reference signs as in the first embodiment. The second embodiment
differs from the first embodiment in the shape of the section of
the receiving portion against which the head rests and the shape of
the head. The receiving portion 100 of the second embodiment has
instead of the spherical segment shaped section 7 a conically
tapering section 70 adjacent to the second end 3. Correspondingly
the head 160 has a second portion 221 with an outer surface which
conically tapers towards the second end 20. The cone angle of the
second portion 221 of the head corresponds to the cone angle of the
portion 70 of the receiving portion. The cone angle is selected
such that in a preassembled state the receiving portion 100 is
still rotatable relative to the head 160.
[0036] The modes of operation are identical to the first
embodiment. Description thereof shall not be repeated.
[0037] The conical outer surface of the bone anchoring device of
the second embodiment may be easier to manufacture than the
spherical outer surface of the bone anchoring device of the first
embodiment.
[0038] Modifications of the embodiments are possible. The diameter
of the threaded portion of the shank 14 can be smaller or larger
than the diameter of the end portion 17. The end portion 17 can
have a conical shape such that the diameter increases towards the
free end. The corresponding first bore 23 of the head can have a
corresponding conical shape. In this case, the diameter of the
first bore 23 is slightly smaller than the diameter of the end
portion. The slits 26 allow an easy opening of the bore 23 and
after inserting the end portion of the shank, the end portion is
slightly clamped. The cone angle can be selected such that a self
locking occurs when the shank is inserted into the head. The head
can have one or more slits which are open towards the first end
19.
[0039] In a further modification, the head can be formed of a
material providing elasticity, for example, a suitable plastic
material. In this case, the slits may be omitted.
[0040] The receiving portion can also be modified. The radius of
the spherical section 7 of the receiving portion of the first
embodiment can be larger than the radius of the head, as long as
the opening is small enough that the head cannot fall out. It is
even possible to have a shape which is not spherical, but rounded
or otherwise tapered towards the opening.
[0041] The head 16 can have a U-shaped recess instead of the
cylindrical recess 27 in such a way that by the U-shaped recess two
free legs are formed. The dimensions of the U-shaped recess are
such that the logo project above the rod 28 when the rod 28 is
inserted. In this case it is possible to separately fix the head 16
via the inner screw without fixing the rod 28. To fix the rod 28, a
separate inner screw is necessary.
[0042] The head also can have a flat free end surface.
[0043] In the embodiments described the shank and the head are
separate parts. However, the shank and the head can be formed as a
single piece bone anchoring element. FIG. 7 shows a third
embodiment which includes a bone anchoring element with a shank and
a head formed as a single piece.
[0044] Parts of this embodiment which are identical to the second
or first embodiment have the same reference numerals as those of
the second or first element. The receiving portion 100 is shaped as
the receiving portion of the second embodiment shown in FIG. 4
which has the conically tapering region 70 adjacent to the second
end 3. The bone anchoring element 130 includes a shank 114 having a
bone thread (not shown) and a head 161 fanned as a single piece.
The head 161 has a first portion 121 having a cylindrical outer
surface and an adjacent second portion 122 having a conical outer
surface tapering towards the shank. The diameter of the first
portion is such that the head can slide in the bore 5 of the
receiving portion 100. The cone angle of the conical portion 122
corresponds to that of the conical portion 70 of the receiving
portion. The free end surface 123 of the head is flat and has a
recess 12 for engagement with a screwing-in tool. The flat surface
ensures that it is possible to align the receiving portion.
[0045] In use the bone anchoring element 130 is first inserted into
the receiving portion 100, then it is screwed into the bone.
[0046] When it is fully seated in the bone, the receiving portion
is still rotatable with respect to the head and thus can be aligned
to receive the rod. After inserting the rod 28 the inner screw 30
in tightened and exerts pressure on the rod 28 which exerts
pressure on the head 161. The head is pressed against the opening 6
of the receiving portion or against the conical section 70 and is
locked in its rotational position.
[0047] Modifications are possible. The conical section of the
receiving portion can have another shape. The head can have, for
example, a sperical section instead of the conical section.
[0048] While a particular form of the disclosure has been
illustrated and described, it will be apparent that various
modifications can be made without departing from the spirit and
scope of the disclosure. Accordingly, it is not intended that the
disclosure be limited, except as by the appended claims.
* * * * *