U.S. patent application number 13/101989 was filed with the patent office on 2011-11-10 for receiving part for receiving a rod for coupling the rod to a bone anchoring element, bone anchoring device, method and tool for assembling the same.
Invention is credited to Lutz BIEDERMANN, Berthold DANNECKER.
Application Number | 20110276098 13/101989 |
Document ID | / |
Family ID | 42313901 |
Filed Date | 2011-11-10 |
United States Patent
Application |
20110276098 |
Kind Code |
A1 |
BIEDERMANN; Lutz ; et
al. |
November 10, 2011 |
RECEIVING PART FOR RECEIVING A ROD FOR COUPLING THE ROD TO A BONE
ANCHORING ELEMENT, BONE ANCHORING DEVICE, METHOD AND TOOL FOR
ASSEMBLING THE SAME
Abstract
A receiving part for receiving a rod for coupling the rod to a
bone anchoring element includes a receiving part body with a first
end and a second end; a rod receiving portion with a channel for
receiving a rod, and a head receiving portion for accommodating a
head of a bone anchoring element, the head receiving portion having
an open end at the second end of the receiving part body and being
flexible so as to allow introduction and clamping of the head; and
a locking ring configured to be positioned around the head
receiving portion, wherein the locking ring can assume a first
position with respect to the receiving part body in which the
locking ring is latched to the receiving part body in a position
where the head receiving portion is expandable to facilitate
insertion of a head of a bone anchoring element, and wherein the
locking ring can assume a second position with respect to the
receiving part body in which the locking ring is latched to the
receiving part body in a position where the locking ring compresses
the head receiving portion, such that when a bone anchoring element
has a head inserted in the head receiving portion, the bone
anchoring element is held adjustably at a first angular position
relative to the receiving part. A method for assembling a bone
anchoring device includes inserting the head of the bone anchoring
element into the receiving part body; and moving the locking ring
and the receiving part body relative to each other until the
locking ring assumes the second position with respect to the
receiving part body.
Inventors: |
BIEDERMANN; Lutz;
(VS-Villingen, DE) ; DANNECKER; Berthold; (St.
Georgen, DE) |
Family ID: |
42313901 |
Appl. No.: |
13/101989 |
Filed: |
May 5, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61331518 |
May 5, 2010 |
|
|
|
Current U.S.
Class: |
606/305 ; 29/428;
606/1 |
Current CPC
Class: |
Y10T 29/5397 20150115;
A61B 17/7037 20130101; A61B 17/8685 20130101; Y10T 29/53796
20150115; A61B 17/7032 20130101; A61B 17/88 20130101; A61B 17/7074
20130101; A61B 2017/00526 20130101; Y10T 29/49947 20150115; Y10T
29/53678 20150115; A61B 17/866 20130101; Y10T 29/53974 20150115;
Y10T 29/53978 20150115; Y10T 29/49876 20150115; Y10T 29/49826
20150115 |
Class at
Publication: |
606/305 ; 606/1;
29/428 |
International
Class: |
A61B 17/86 20060101
A61B017/86; B23P 11/00 20060101 B23P011/00; A61B 17/00 20060101
A61B017/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 5, 2010 |
EP |
10 162 063.1 |
Claims
1. A receiving part for receiving a rod for coupling the rod to a
bone anchoring element, the receiving part comprising: a receiving
part body with a first end and a second end, a rod receiving
portion with a channel for receiving a rod, and a head receiving
portion for accommodating a head of a bone anchoring element, the
head receiving portion having an open end at the second end of the
receiving part body and being flexible so as to allow introduction
and clamping of the head; and a locking ring configured to be
positioned around the head receiving portion, wherein the locking
ring can assume a first position with respect to the receiving part
body in which the locking ring is latched to the receiving part
body in a position where the head receiving portion is expandable
to facilitate insertion of a head of a bone anchoring element, and
wherein the locking ring can assume a second position with respect
to the receiving part body in which the locking ring is latched to
the receiving part body in a position where the locking ring
compresses the head receiving portion, such that when a bone
anchoring element has a head inserted in the head receiving
portion, the bone anchoring element is held adjustably at a first
angular position relative to the receiving part.
2. The receiving part of claim 1, wherein when the locking ring is
in the second position, the locking ring provides a first
compression force on the head receiving portion such that when a
head of a bone anchoring element is inserted in the head receiving
portion, the head is not fully locked.
3. The receiving part of claim 2, wherein the locking ring can
assume a third position with respect to the receiving part body in
which the locking ring compresses the head receiving portion with a
second compression force greater than the first compression force,
such that when a head of a bone anchoring element is inserted in
the head receiving portion, the head is fully locked in the head
receiving portion.
4. The receiving part of claim 1, wherein in the first position,
the locking ring is prevented from moving in an axial direction
towards the first end of the receiving part body, but is movable
towards the second end of the receiving part body by application of
a force.
5. The receiving part of claim 1, wherein the locking ring has a
first projection or a first recess which is configured to cooperate
with a corresponding first recess or first projection of the
receiving part body to latch the locking ring in the first
position.
6. The receiving part of claim 5, wherein the receiving part body
has an asymmetric recess.
7. The receiving part of claim 1, wherein in the second position,
the locking ring is prevented from moving in an axial direction
towards the first end of the receiving part body, but is movable
towards the second end of the receiving part body by application of
a force.
8. The receiving part of claim 7, wherein the receiving part body
has an asymmetric recess.
9. The receiving part of claim 1, wherein when the locking ring is
positioned around the receiving part body, the locking ring has a
first annular portion which is non-resilient and which is arranged
to be closer to the second end of the receiving part body and a
second annular portion which is resilient and which is arranged to
be closer to the first end of the receiving part body.
10. The receiving part of claim 1, wherein the head receiving
portion has an exterior surface with a tapered or curved portion
and the locking ring has an interior surface with a correspondingly
tapered or curved portion which are configured to cooperate with
one another, such that when a head of a bone anchoring element is
inserted in the head receiving portion, the head is clamped when
the locking ring is moved towards the second end.
11. The receiving part of claim 10, wherein the locking ring
further comprises an inwardly projecting edge at one end which
cooperates with the head receiving portion near the second end of
the receiving part body to provide additional clamping.
12. A bone anchoring device comprising: a bone anchoring element
comprising a shaft with a threaded portion and a head with a
spherical outer surface portion; and a receiving part for receiving
a rod for coupling the rod to the bone anchoring element, the
receiving part comprising: a receiving part body with a first end
and a second end, a rod receiving portion with a channel for
receiving a rod, and a head receiving portion for accommodating the
head of the bone anchoring element, the head receiving portion
having an open end at the second end of the receiving part body and
being flexible so as to allow introduction and clamping of the
head; and a locking ring configured to be positioned around the
head receiving portion, wherein the locking ring can assume a first
position with respect to the receiving part body in which the
locking ring is latched to the receiving part body in a position
where the head receiving portion is expandable to facilitate
insertion of the head, and wherein the locking ring can assume a
second position with respect to the receiving part body in which
the locking ring is latched to the receiving part body in a
position where the locking ring compresses the head receiving
portion to compress the inserted head, such that the bone anchoring
element is held adjustably at a first angular position relative to
the receiving part.
13. A method for assembling a bone anchoring device, the bone
anchoring device comprising a bone anchoring element comprising a
shaft for anchoring in a bone and a head, and a receiving part for
receiving a rod for coupling the rod to the bone anchoring element,
the receiving part comprising a receiving part body for
accommodating the head of the bone anchoring element in a polyaxial
manner, and a locking ring, in a first position with respect to the
receiving part body in which the locking ring is latched to the
receiving part body in a position in which the head of the bone
anchoring element can be introduced into the receiving part body
and can freely pivot therein, the method comprising: inserting the
head of the bone anchoring element into the receiving part body;
and moving the locking ring and the receiving part body relative to
each other until the locking ring assumes a second position with
respect to the receiving part body in which the locking ring is
latched to the receiving part body in a position where the locking
ring compresses a portion of the receiving part body to compress
the head, such that the bone anchoring element is held adjustably
at a first angular position relative to the receiving part.
14. The method of claim 13, wherein the shaft of the bone anchoring
element comprises a threaded portion and the head of the bone
anchoring element comprises a spherical outer surface portion,
wherein the receiving part body has a first end and a second end, a
rod receiving portion with a channel for receiving a rod, and a
head receiving portion for accommodating the head of the bone
anchoring element, the head receiving portion having an open end at
the second end of the receiving part body and being flexible so as
to allow introduction and clamping of the head, and wherein the
locking ring is configured to be positioned around the head
receiving portion.
15. The method of claim 13, wherein a same tool is utilized for
both the inserting of the head and the moving of the locking ring
and the receiving part body relative to each other.
16. The method of claim 15, wherein a first holder of the tool
holds the bone anchoring element and a second holder of the tool
holds the receiving part, and wherein the first holder and the
second holder are moved closer relative to one another for both the
inserting of the head and the moving of the locking ring and the
receiving part body relative to each other.
17. A tool for assembling a bone anchoring device, the bone
anchoring device comprising a bone anchoring element with a head
and a shaft to be anchored in a bone, and a receiving part for
receiving a rod for coupling the rod to the bone anchoring element,
the receiving part comprising a receiving part body with a head
receiving portion for accommodating the head of the bone anchoring
element and a locking ring configured to be positioned around the
head receiving portion, the tool comprising: a first holder for
holding a bone anchoring element; and a second holder for holding a
receiving part, wherein the first and second holders are movable
relative to one another, such that when the first holder is holding
a bone anchoring element and the second holder is holding a
receiving part, the movement between the first and second holders
is configured to press the bone anchoring element against the
receiving part body or the locking ring, and wherein the tool
further comprises an abutment device which is adjustable between a
first configuration to provide a first abutment for preventing
movement of the receiving part body with respect to the second
holder when the first holder is moved towards the second holder to
engage the bone anchoring element with the receiving part body, and
a second configuration to provide a second abutment for preventing
movement of the locking ring with respect to the second holder when
the first holder is moved further towards the second holder, such
that the bone anchoring element with the engaged receiving part
body is moved relative to the locking ring to adjust the locking
ring from the first position to the second position.
18. The tool of claim 17, wherein the second holder has a recess
for inserting the receiving part body, and wherein the abutment
device is configured to adjust the depth of the recess between a
first depth for the second holder to provide the first abutment and
a second depth for the second holder to provide the second
abutment.
19. A method for coupling a rod to a bone anchoring element via a
receiving part, the bone anchoring element comprising a shaft and a
head, and the receiving part comprising a receiving part body with
a first end and a second end, a rod receiving portion with a
channel for receiving a rod, and a head receiving portion for
accommodating the head of the bone anchoring element, the head
receiving portion having an open end at the second end of the
receiving part body and being flexible so as to allow introduction
and clamping of the head, and a locking ring around the head
receiving portion in a first position with respect to the receiving
part body in which the locking ring is latched to the receiving
part body in a position where the head receiving portion is
expandable and in which the head of the bone anchoring element can
be introduced into the head receiving portion and can freely pivot
therein, the method comprising: inserting the bone anchoring
element in a first holder of a tool, and inserting the receiving
part in a second holder of the tool; moving one of the first holder
or the second holder towards the other one of the first holder or
the second holder to insert the head of the bone anchoring element
into the head receiving portion of the receiving part body;
adjusting the tool; moving the one of the first holder or the
second holder further towards the other one of the first holder or
the second holder to move the locking ring and the receiving part
body relative to each other until the locking ring assumes a second
position with respect to the receiving part body in which the
locking ring is latched to the receiving part body in a position
where the locking ring compresses the head receiving portion to
compress the head, such that the bone anchoring element is held
adjustably at a first angular position relative to the receiving
part; and removing the attached bone anchoring element and
receiving part from the tool.
20. The method of claim 19, further comprising: inserting the shaft
of the bone anchoring element into a bone; applying a force on the
receiving part to move the bone anchoring element to a second
angular position relative to the receiving part, wherein in the
second angular position the receiving part is aligned with a rod;
inserting the rod into the channel of the receiving part body; and
locking the rod in the receiving part and locking the receiving
part at the second angular position relative to the bone anchoring
element.
21. The method of claim 20, further comprising: attaching at least
one additional bone anchoring element and receiving part assembly
to the same bone or a different bone; aligning the receiving part
of the at least one additional assembly with the rod; and locking
the rod in the receiving part and locking an angular position of
the receiving part relative to the bone anchoring element for each
of the at least one additional assembly.
22. A tool for assembling a bone anchoring device, the bone
anchoring device comprising a bone anchoring element with a head
and a shaft to be anchored in a bone, and a receiving part for
receiving a rod for coupling the rod to the bone anchoring element,
the receiving part comprising a receiving part body with a head
receiving portion for accommodating the head of the bone anchoring
element and a locking ring configured to be positioned around the
head receiving portion, the tool comprising: a first holder for
holding a bone anchoring element; and a second holder for holding a
receiving part, wherein the first and second holders are movable
relative to one another, and wherein at least one of the first
holder or the second holder has a first abutment, a second
abutment, and a recess, and wherein the first abutment is movable
to adjust a depth of the recess independent from the movement
between the first holder and the second holder.
23. The tool of claim 22, wherein the recess is on the second
holder and is for inserting a receiving part body, and wherein the
first abutment is configured to adjust the depth of the recess.
24. The tool of claim 23, wherein the second holder comprises an
insert, the first abutment is defined by a wall of the insert, and
the insert has a hole adjacent to the first abutment, and wherein
the insert is movable between a first position where the first
abutment is aligned with the recess and a second position where the
hole is aligned with the recess.
25. The tool of claim 23, wherein the tool further comprises an
insert for receiving the bone anchoring element, the insert
configured to be inserted into the first holder.
26. The tool of claim 25, wherein the first holder has a recess
configured to receive the insert.
27. The tool of claim 25, wherein the insert has at least two
recesses.
28. The tool of claim 27, wherein the recesses on the insert are
cylinder-shaped or U-shaped.
29. The tool of claim 27, wherein the recesses on the insert extend
over the whole length of the insert.
30. The tool of claim 25, wherein the insert is rotatable while in
the first holder.
31. The tool of claim 22, further comprising a handle and lever,
wherein the first holder or the second holder is connected to the
handle and lever and is configured to be moved towards the other
one of the first holder or the second holder by actuation of the
handle and lever.
32. The tool of claim 31, further comprising a frame, wherein a
position of the other one of the first holder or the second holder
is fixed with respect to the frame.
33. A receiving part for receiving a rod for coupling the rod to a
bone anchoring element, the receiving part comprising: a receiving
part body with a first end and a second end, a rod receiving
portion with a channel for receiving a rod, and a head receiving
portion for accommodating a head of a bone anchoring element, the
head receiving portion having an open end at the second end of the
receiving part body and being flexible so as to allow introduction
and clamping of the head; and a locking ring configured to be
positioned around the head receiving portion, wherein the locking
ring can assume a first position with respect to the receiving part
body in which the locking ring is latched to the receiving part
body in a position where the head receiving portion is expandable,
wherein the locking ring can assume a second position with respect
to the receiving part body in which the locking ring is latched to
the receiving part body in a position where the locking ring
compresses the head receiving portion inwardly towards a central
axis of the receiving part body, and wherein the locking ring can
assume a third position with respect to the receiving part body
where the locking ring compresses the head receiving portion
inwardly closer towards the central axis of the receiving part body
than when the locking ring is in the second position.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] The present application claims priority to and the benefit
of U.S. Provisional Patent Application Ser. No. 61/331,518, filed
May 5, 2010, the contents of which are hereby incorporated by
reference in their entirety, and claims priority from European
Patent Application EP 10 162 063.1, filed May 5, 2010, the contents
of which are hereby incorporated by reference in their
entirety.
BACKGROUND
[0002] 1. Field of the Invention
[0003] The invention relates to a receiving part for receiving a
rod for coupling the rod to a bone anchoring element, a bone
anchoring device with such a receiving part, a method and a tool
for assembling the bone anchoring device. The receiving part
includes a receiving part body and a locking ring. The locking ring
can assume a first position in which it is latched with respect to
the receiving part body and in which a head of the bone anchoring
element can be inserted, and a second position in which it is
latched with respect to the receiving part body and in which the
bone anchoring element is held in an adjustable angular position
but is not fully locked. The bone anchoring device can be realized,
for example, in the form of a polyaxial bone screw. The method of
assembling includes the steps of providing the receiving part body
and the locking ring in the first position, inserting the head and
moving the locking ring to the second position. A tool is
configured for the execution of the steps.
[0004] 2. Description of Related Art
[0005] WO 2007/038350 A2 discloses an apparatus for connecting a
bone anchor to a support rod, the apparatus including a connector
body and a cap. The connector body has a socket for insertion,
angulation and removal of a bone anchor. A sleeve is provided,
which is configured to fit over the connector body in a temporary
position, in which the sleeve permits insertion of the bone anchor,
to move to a provisional locking position in which the sleeve
permits angulation but prevents removal of the bone anchor, and to
move to a locking position, in which the sleeve prevents both
angulation and removal of the bone anchor.
SUMMARY
[0006] If a head of an anchoring element is freely pivotable with
respect to a receiving part, alignment of the receiving part and
insertion of a rod may be difficult in more complex clinical
applications, for example, when multiple bone anchors are to be
connected to the rod.
[0007] In some instances, there is also a need to have a choice
between different anchoring elements during surgery, to select the
most appropriate anchoring elements for a specific clinical
application.
[0008] It is the object of the invention to provide an improved
receiving part for receiving a rod for coupling the rod to a bone
anchoring element, a bone anchoring device with such a receiving
part which provides for safer handling during surgery and which
allows for selection of an appropriate bone anchoring element to
assemble with the receiving part. Further objectives are to provide
a method for assembling the bone anchoring device which can be
easily carried out, and to provide a tool for assembly of the bone
anchoring device.
[0009] The receiving part according to an exemplary embodiment of
the invention allows the insertion of the head of the bone
anchoring element into the receiving part body when the locking
ring is in a first position which is an insertion position. In this
position, the locking ring is latched with respect to the receiving
part body. Therefore, the locking ring cannot be inadvertently
moved to compress the head receiving portion of the receiving part
body, in order to facilitate the insertion of the head.
[0010] In a second position, which is a pre-locking position, the
locking ring is latched with respect to the receiving part body and
the head receiving portion is compressed so that the bone anchoring
element is held in an adjustable angular position but is not fully
locked. This prevents inadvertent removal of the anchoring element
and holds the receiving part body in an adjustable angular position
with respect to the head of the bone anchoring element. Therefore,
safe and convenient handling of the bone anchoring device during
surgery can be assured.
[0011] In a third position, which is a locking position, the
locking ring compresses the head receiving portion such that the
bone anchoring element is fully locked and cannot pivot.
[0012] The receiving part body and the locking ring may be
preassembled, and may be delivered after manufacture in a
configuration in which the locking ring is latched in the first
position to allow introduction of the head of the bone anchoring
element. A suitable bone anchoring element, for example, a bone
screw with a desired diameter and length, can be selected and
inserted into the receiving part. Thereafter, the locking ring can
be moved into the second position with respect to the receiving
part, in which the head is pre-locked. The latching of the locking
ring in the receiving part body in the second position is audible,
so that a person who assembles the bone anchoring device can be
sure of correct assembly of the bone anchoring element in the
receiving part. In the pre-locked condition, the bone anchoring
element may only be pivotable with respect to the receiving part by
applying an additional force, to overcome the frictional force of
the clamping of the head.
[0013] With the bone anchoring device according to embodiments of
the invention, a modular system can be provided, which allows
combinations of various anchoring elements with any suitable
receiving part on demand, depending on the actual clinical
requirements. This reduces costs associated with polyaxial screws,
reduces inventory, and gives the surgeon a wide choice of
implants.
[0014] The method of assembling the bone anchoring device can be
carried out by any specialist, for example, by a surgeon or any
personnel assisting him or her before or during surgery.
[0015] The tool is easy to handle and enables safer assembly.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Further features and advantages of the invention will become
apparent from the description of embodiments by means of the
accompanying drawings. In the drawings:
[0017] FIG. 1 shows a perspective exploded view of a bone anchoring
device according to an embodiment of the invention;
[0018] FIG. 2 shows a perspective view of the bone anchoring device
of FIG. 1 in an assembled state;
[0019] FIG. 3 shows an enlarged perspective view of a locking ring
according to an embodiment of the invention;
[0020] FIG. 4 shows a cross-sectional view of the locking ring
shown in FIG. 3 along line A-A in FIG. 3;
[0021] FIG. 5 shows a cross-sectional view of a bone anchoring
device according to an embodiment of the invention in an assembled
state, the section being taken perpendicular to a rod axis, where
the locking ring is in a first position and is latched with respect
to the receiving part body;
[0022] FIG. 6 shows a cross-sectional view of the bone anchoring
device in an assembled state, the section being taken in a plane
perpendicular to the rod axis, where the locking ring is in a
second position and is latched with respect to the receiving part
body;
[0023] FIG. 7 shows a cross-sectional view of the bone anchoring
device in an assembled state, with a rod inserted and fixed, the
section being taken in a plane perpendicular to the rod axis, and
wherein the locking ring is in a third position;
[0024] FIG. 8 shows a cross-sectional view of a portion of the bone
anchoring device in a first assembly step where a bone anchoring
element is going to be inserted into the receiving part;
[0025] FIG. 9 shows a cross-sectional view of a portion of the bone
anchoring device in a second assembly step where a head of the bone
anchoring element has been introduced into the receiving part and
is pre-locked;
[0026] FIG. 10 shows a cross-sectional view of a portion of the
bone anchoring device, where the head is locked;
[0027] FIG. 11 shows an enlarged cross-sectional view of a portion
of the receiving part, wherein the locking ring is in the first
position and is latched with respect to the receiving part body to
allow for introduction of the head;
[0028] FIG. 12 shows an enlarged cross-sectional view of a portion
of the bone anchoring device in the final locked state where
additional clamping is effected by means of the locking ring;
[0029] FIG. 13 shows a perspective view of a tool for assembling a
bone anchoring device according to an embodiment of the
invention;
[0030] FIG. 14 shows an enlarged perspective view of a portion of
the tool with a bone anchoring element inserted into a holder;
[0031] FIG. 15 shows a perspective view of a portion of the tool
with a receiving part to be inserted into the holder;
[0032] FIG. 16 shows a perspective view of a portion of the tool
with the receiving part introduced into a holder;
[0033] FIG. 17a shows a perspective view of the tool depicting a
step of assembly, where the head of the bone anchoring element is
going to be inserted into the receiving part;
[0034] FIG. 17b shows an enlarged view of a portion of FIG.
17a;
[0035] FIG. 18a shows a perspective view of the tool depicting
another step of assembly, with the head of the bone anchoring
element inserted into the receiving part.
[0036] FIG. 18b shows an enlarged portion of FIG. 18a;
[0037] FIG. 19 shows an enlarged perspective view of a portion of
the tool and the bone anchoring device after insertion of the head
and before entering the pre-locking position;
[0038] FIG. 20 shows a perspective view of the tool with the bone
anchoring device in the pre-locking position;
[0039] FIG. 21 shows a perspective view of an enlarged portion of
the tool, where the locking ring of the bone anchoring device has
assumed the pre-locking position and clamps the head;
[0040] FIG. 22 shows a perspective view of a tool according to a
second embodiment of the invention, depicting a step of assembly
where the head of the bone anchoring element is to be inserted into
the receiving part;
[0041] FIG. 23a shows an insert for a first holder according to the
second embodiment, in the form of a cylindrical section having
several cylinder-shaped or U-shaped recesses;
[0042] FIG. 23b shows a first holder according to the second
embodiment;
[0043] FIG. 24 shows the first holder and the insert in an
assembled state according to the second embodiment;
[0044] FIG. 25 shows a cross-sectional view of the insert according
to the second embodiment; and
[0045] FIG. 26 shows a cross-sectional view of a frame, the first
holder, and the insert, the assembly holding a screw according to
the second embodiment.
DETAILED DESCRIPTION
[0046] As shown in FIGS. 1 to 7, a bone anchoring device according
to an embodiment of the invention includes a bone anchoring element
1 in the form of a bone screw having a threaded shaft 2 and a head
3 with a curved surface portion. In this embodiment the head is
spherical segment-shaped. The head 3 has a recess 4 for engagement
with a tool. The bone anchoring device also includes a receiving
part body 5 for receiving a rod 6 to connect it to the bone
anchoring element 1. Further, a fixation element 7 in the form of
an inner screw is provided for fixing the rod 6 in the receiving
part body 5. The bone anchoring device also includes a locking ring
8 for locking the head 3 in the receiving part body 5.
[0047] The receiving part body 5 includes a rod receiving portion
9, which is substantially cylindrical and which has a first end 9a
and a second end 9b opposite the first end 9a. A coaxial first bore
10 is provided at the second end 9b as shown in FIGS. 5 to 7. The
diameter of the first bore 10 is smaller than the diameter of the
head 3 of the bone anchoring element 1. The rod receiving portion 9
further has a coaxial second bore 11 extending from the first end
9a to a distance from the second end 9b. The diameter of the second
bore 11 is larger than that of the first bore 10. A substantially
U-shaped recess 12 extends from the first end 9a in the direction
of the second end 9b in the rod receiving portion 9, the diameter
of the recess 12 being slightly larger than the diameter of the rod
6 in such a way that the rod 6 can be placed in the recess 12 and
can be guided therein. By means of the recess 12, two free legs
12a, 12b are fowled on which an internal thread 13 is provided. The
internal thread 13 can be a metric thread, a flat thread, a
negative angle thread, a saw-tooth thread, or any other type of
thread. Preferably, a thread such as a flat thread or negative
angle thread is used, which prevents splaying of the legs 12a, 12b
when the inner screw 7 is screwed-in. The depth of the recess 12 is
such that the rod 6 and the inner screw 7 can be inserted between
the legs 12a and 12b.
[0048] As can be seen in FIG. 1, cut-outs 15 are provided in the
rod receiving portion 9 on either end of the channel formed by the
recess 12.
[0049] On an outer surface of the rod receiving portion 9, in the
region of the legs 12a, 12b, a groove 16 is provided, which extends
in a circumferential direction and serves for engagement with a
portion of the locking ring 8. The groove 16 is asymmetric in such
a way that it allows for disengagement between the locking ring 8
and the groove 16 when the locking ring 8 is shifted in one
direction. The asymmetric shape of the groove 16 is realized by a
downwardly inclined lower wall 16a and an upper wall 16b that is
substantially perpendicular to an outer surface of the rod
receiving portion 9.
[0050] At the side of the second end 9b the receiving part body 5
comprises a head receiving portion 17 providing an accommodation
space for the head 3 of the bone anchoring element 1. A largest
outer diameter of the head receiving portion 17 is smaller than a
largest outer diameter of the rod receiving portion 9. An internal
hollow section 18 forms a seat for the head 3 of the bone anchoring
element 1, and is open via an opening 19 to a free end 17b of the
head receiving portion 17. The hollow section 18 corresponds in its
shape to the shape of the head 3. In the embodiment shown, the
hollow section 18 is a spherical section to accommodate the
spherical head 3. Furthermore, the hollow section 18 is configured
to encompass the head 3 of the bone anchoring element 1 from the
side, covering a region including the largest diameter of the head
3.
[0051] A plurality of slits 20 are provided in the head receiving
portion 17, which are open to the free end 17b. The slits 20 make
the head receiving portion 17 flexible so that it can be compressed
to clamp and finally lock the head 3 in the hollow internal portion
18 by means of friction. The number and size of slits 20 is
provided depending on the desired flexibility of the head receiving
portion 17. The flexibility of the head receiving portion 17 is
such that the head 3 of the anchoring element 1 can be inserted by
expanding the head receiving portion 17, and the head 3 can be
clamped by compressing the head receiving portion 17.
[0052] The outer surface of the head receiving portion 17 has a
first section 21, with an outer diameter which increases towards
free end 17b, for example, in an outwardly curved or conically
widening manner. Adjacent to the first section 21, there is a
circumferential groove 22, which is recessed with respect to the
first section 21 and which serves for engagement with a
corresponding portion of the locking ring 8. The groove 22 is
asymmetric to allow for disengagement between the locking ring 8
and the groove 22 when moving the locking ring 8 in one direction.
The asymmetric shape of the groove 22 is realized by a lower
downwardly inclined wall 22a and an upper wall 22b that is
substantially perpendicular to an outer surface of the head
receiving portion 17.
[0053] Adjacent the groove 22 on a side opposite the first section
21, there is a third portion 23 of the head receiving portion 17
with a substantially cylindrical outer surface. The third portion
23 is configured to cooperate with a portion of the locking ring 8
to enhance the clamping effect of the locking ring 8.
[0054] The locking ring 8 will now be described with reference to
FIGS. 1 to 7. The locking ring 8 is substantially cylindrical and
has an upper end 8a and a lower end 8b. In the mounted state the
upper end 8a is oriented in the direction of the first end 9a of
the rod receiving portion 9, while the lower end 8b is oriented
towards the free end 17b of the head receiving portion 17. Near the
lower end 8b, a first portion 81 with an inner surface 81a is
provided which cooperates with the first outer surface portion 21
of the head receiving portion 17 to compress the head receiving
portion 17. The outer surface of the first portion 81 may also be
tapered to reduce an outer bottom diameter. The size of the first
portion 81 is such that, for example, the tapered inner surface 81a
can engage the outer surface portion 21 of the head receiving
portion 17 to exert a compression force onto the head receiving
portion 17. The inner surface 81a of the first portion 81 of the
locking ring 8 can also be curved with a curvature directed towards
a center of the locking ring.
[0055] At the lower end 8b, the locking ring 8 includes an inwardly
projecting edge 82, the inner diameter of which is smaller than the
inner diameter of the other portions of the locking ring 8. The
inwardly projecting edge 82 is configured to engage the groove 22
of the head receiving portion 17.
[0056] The locking ring 8 further has a third portion 83 with
upwardly extending wall portions 83a, which are separated from each
other by slits 84. The upwardly extending wall portions 83a are
arranged at an outer circumference of an inner circumferential
shoulder 85 of the locking ring 8, and render the third portion 83
of the locking ring flexible. The number and size of the slits 84
and the thickness of the wall portions 83a are configured such that
a desired flexibility is realized. At the free ends of the wall
portions 83a are engagement sections 83b which are shaped so as to
engage the groove 16 provided on the outer surface of the rod
receiving portion 9. The inner diameter of the third portion 83 of
the locking ring 8 is only slightly larger than the outer diameter
of the rod receiving portion 9, as can be seen in FIG. 5.
[0057] The locking ring 8 is sized in such a way with respect to
the head receiving portion 17, that the head receiving portion 17
can expand within the locking ring 8 to allow the introduction of
the head 3 when the locking ring 8 is in the first position, as
shown in FIG. 5.
[0058] Two projections 86, which are located diametrically opposite
to each other, are formed in the third portion 83 of the locking
ring. The projections 86 have a height where they extend into the
cut-outs 15 and project above the bottom of the substantially
U-shaped recess 12 when the locking ring 8 is in a position in
which the head 3 is not yet locked, as shown in FIGS. 5 and 6. A
free end surface 86a of the projections 86 can be curved,
particularly inwardly curved, with a curvature corresponding to an
outer surface of the rod 6. The locking ring is arranged in such a
manner around the head receiving portion 17 of the receiving part
body 5, that the projections 86 are located at the positions of
(e.g., are aligned with) the recess 12. Here, the projections 86
prevent the locking ring 8 from rotating when the rod 6 is not
inserted.
[0059] The flexibility of the head receiving portion 17 and the
size of the head receiving portion 17 at the open end 17b allows
for mounting of the locking ring 8 by assembling the locking ring 8
from the free end 17b onto the head receiving portion 17. Since the
outer diameter of the head receiving portion is smaller than that
of the rod receiving portion 9, the locking ring 8 may only project
minimally beyond the rod receiving portion 9 in a radial
direction.
[0060] The inner screw 7 has a thread corresponding to the internal
thread 13 provided on the legs 12a, 12b. If a thread type which
prevents the legs 12a, 12b from splaying is used, a single fixation
element such as the inner screw 7 is sufficient. This reduces the
size of the bone anchoring device in a radial direction. Other
fixation elements such as, for example, an outer nut are also
possible.
[0061] The receiving part body 5, the locking ring 8, the inner
screw 7 and the bone anchoring element 1 are made of bio-compatible
materials, for example, titanium or stainless steel or a
bio-compatible alloy such as nitinol or a bio-compatible plastic
material, such as polyether ether ketone (PEEK). The parts can be
made of the same or of different materials.
[0062] The function of the locking ring 8 is now explained with
referenced FIGS. 5 to 12. As shown in FIG. 5, the locking ring 8 is
in a first position, which is an insertion position where the
locking ring 8 is latched with respect to the receiving part body
5. In the first position, the inwardly projecting edge 82 of the
locking ring 8 engages groove 22 on the outer surface of the head
receiving portion 17. As can be seen in the figures, the inner
diameter of the inwardly projecting edge 82 is larger than the
outer diameter of the head receiving portion 17 at the position of
the groove 22, so as to allow for expansion of the head receiving
portion 17 when the head 3 is introduced. In the first position,
the locking ring 8 is additionally held by a clamping force between
the rod receiving portion 9 of the receiving part body 5 and the
flexible wall portions 83a of the locking ring 8, which are
slightly bent outwards, as can be seen in particular in FIGS. 5, 8,
and 11.
[0063] When the locking ring 8 is in the first position, the head
receiving portion 17 is not compressed. In this position, the
introduction of the screw head 3 is possible as can be seen in FIG.
8. In the first position, the locking ring 8 is prevented from
moving upwards towards the first end 9a of the rod receiving
portion 9, since the shoulder 85 of the locking ring 8 abuts
against the second end 9b of the rod receiving portion 9b, while
the inwardly projecting edge 82 of the locking ring 8 abuts against
the upper wall 22b of groove 22. As shown in particular in FIG. 8,
the abutment of the locking ring against the second end 9b and
against the upper wall of groove 22 holds the locking ring 8 in
place against upward movement. The inclined lower wall 22a of the
groove 22 prevents inadvertent downward movement of the locking
ring 8, but allows downward movement of the locking ring 8 upon
exertion of an additional force. Since portions of the inner
diameter of the locking ring 8 are larger than corresponding
portions of the outer diameter of the head receiving portion 17 in
a non-compressed state in the first position, an expansion of the
head receiving portion 17 into the space between the locking ring 8
and the head receiving portion 17 is possible. In addition, in the
first position, the head 3 can freely pivot.
[0064] FIGS. 6 and 9 illustrate the bone anchoring device in a
second position in which the locking ring 8 is latched with respect
to the receiving part body 5 in a pre-locking position. In the
second position, the locking ring 8 has been shifted from the first
position towards the free end 17b of the head receiving portion 17
until the engagement portions 83b of the flexible wall portions 83a
resiliently snap into the groove 16 provided on the rod receiving
portion 9. Once in the second position, the free upper edge of the
engagement portions 83b abut against the upper wall 16b of the
groove 16, as shown in FIGS. 6 and 9, thereby preventing upward
movement of the locking ring 8 out of the pre-locking position. On
the other hand, the inclined lower wall surface 16a of the groove
16 prevents inadvertent downward movement of the locking ring 8
towards the free end 17b, but allows for downward movement upon
exertion of an additional force.
[0065] In the second position, as can be seen in particular in
FIGS. 6 and 9, the inner inclined surface 81a of the locking ring 8
presses against the first outer surface portion 21 of the head
receiving portion 17, so as to compress the head receiving portion
17 to clamp the head 3 within the hollow internal portion 18,
without fully locking the head 3. In addition, the inwardly
projecting edge 82 of the locking ring 8 presses against the third
portion 23 of the head receiving portion 17, resulting in an
additional clamping force. Therefore, clamping of the head 3 can be
effected not only from above and/or the sides of the head 3 but
also from a region around the lower portion of head 3. Pre-locking
means that under conditions arising during surgery, the angular
position of the bone anchoring element 1 with respect to the
receiving part body 5 is maintained, and can be loosened only by
exerting an additional force onto the receiving part body 5 and/or
the bone anchoring element 1 of the bone anchoring device. In the
pre-locked position, the bone anchoring element 1 cannot be removed
from the receiving part 5. Hence, accidental or inadvertent removal
of the head 3 is not possible. However, angulation of the bone
anchoring device to be adjusted to a desired angle is still
possible, for example, by manual adjustment.
[0066] A third position, which is the locking position, is shown in
FIGS. 7, 10, and 12. The third position is defined as a position in
which the screw head 3 is finally locked within the head receiving
portion 17. The inner surface 81a of the locking ring 8 engages the
outer surface of the first portion 21 of the head receiving portion
17 in such a way that the head 3 is locked by compression of the
head receiving portion 17. In addition, the inwardly projecting
edge 82 of the locking ring 8 further compresses the head receiving
portion 17 at the third portion 23, thereby enhancing the locking
force.
[0067] The dimensions of the receiving part body 5 and the locking
ring 8 are configured such that desired clamping forces can be
achieved in the second position and in the third position,
respectively.
[0068] The third position can be reached by shifting the locking
ring 8 relative to the receiving part body 5 such that the
engagement portions 83b and the inwardly projecting ring 82 slide
along the lower inclined wall portions 16a and 22a of the grooves
16, 22, respectively.
[0069] The bone anchoring device is preassembled as follows. First,
the locking ring 8 is mounted onto the receiving part body 5 from
the free end 17b. This can be done, for example, by the
manufacturer. Preferably, the locking ring 8 is in the first
position in which it is latched by engagement or alignment of the
inwardly projecting edge 82 with the groove 22.
[0070] Thereafter, the head 3 of the anchoring element 1 can be
introduced from the free end 17b into the hollow internal portion
18 of the head receiving portion 17. Thereafter, the locking ring 8
is moved downwards relative to the receiving part body 5, so that
the inwardly projecting ring 82 slides out of the groove 22 and the
engagement portions 83b of the flexible wall portions 83a snap into
groove 16, to reach the second position, in which the head 3 is
pre-locked by frictional clamping.
[0071] A tool for assembling the bone anchoring device and its
operation will now be described with reference to FIGS. 13 to 21.
The tool 100 includes a frame 101 with a first holder 102 for the
bone anchoring element 1 and a second holder 103 for the receiving
part (including, for example, the receiving part body 5 and the
locking ring 8). The holders 102, 103 are oriented such that the
screw axis is horizontal or parallel with respect to a surface on
which the tool is placed or positioned. The holder 102 has a recess
102a for the shank 2 of the bone anchoring element 1, which serves
for holding and guiding the shank 2. The diameter of the recess
102a is smaller than the diameter of the head 3 in the area of a
free end of the holder 102 facing the second holder 103. Therefore,
a free end surface 102b of the holder 102 serves as an abutment for
the head 3 of the bone anchoring element 1. The holder 102 is
supported on the frame 101.
[0072] The holder 103 for the receiving part is also supported on
the frame 101. It has a substantially circular recess 103, for
accommodating a portion of the receiving part. The orientation of
the holder 103 with respect to the holder 102 is such that a
central axis of the receiving part is configured to be positioned
coaxial with the screw axis when the receiving part and the bone
anchoring element are both inserted into their respective holders.
The circular recess 103a can be adjusted to have two different
depths. This may be realized by an insert 104 which is inserted in
a corresponding slot provided in the holder 103 and which can be
shifted in a direction transverse to the direction of the central
axis of the recess 103a, to limit the depth of recess 103a. The
insert 104 has one circular recess 142. In position 1, as shown in
FIGS. 13 to 18, the insert limits the depth of the recess 103a to a
first depth 141, and thus provides an abutment for the first end 9a
of the receiving part body 5. In position 2 which is shown in FIGS.
19 to 21 the insert 104 is shifted such that its recess 142 forms
or defines the bottom of the recess 103a of the holder 103, the
depth of which is greater than the depth 141 of the recess 103a
when the insert 104 is in the first position. As such, recess 142
effectively increases the length of the recess 103a. The receiving
part can therefore be inserted deeper into the recess 103a until an
outer surface 103b of the holder 103 forms an abutment for the
locking ring 8 as shown in FIGS. 19 to 21. The shape of the recess
103a need not be circular, but can be otherwise shaped, and in
particular, it can be adapted to correspond to the contour of the
receiving part.
[0073] The holder 102 for the bone anchoring element 1 is movable
relative to the holder 103 for the receiving part body 5 in an
axial direction. The holder 102 can be actuated via a lever 105 and
a handle 106. It is to be understood that the lever 105 is only an
example, and that movement of the holder 102 for the bone anchoring
element 1 can be effected in many other ways.
[0074] The dimensions of the tool 100 are configured such that, by
movement of the holder 102 for the bone anchoring element 1 with
respect to the holder 103 in which a receiving part is inserted, a
sufficient force can be exerted to introduce the head 3 of the bone
anchoring element 1 into the head receiving portion 17, when the
recess 103a is set to have the first depth 141 and the locking ring
8 is in the first position. It is further configured such that a
sufficient force can be exerted onto the locking ring 8 when holder
102 is moved again relative to the holder 103 to move the locking
ring 8 out of the first position into the second position, when the
recess 103a is set to have the second depth 142.
[0075] The operation of the tool is shown in FIGS. 17 to 21. As
shown in FIGS. 17a and 17b first, the bone anchoring element 1 is
inserted into the holder 102 and the receiving part body 5, with
mounted locking ring 8 in the first position, is mounted in the
recess 103a of the holder 103 when the recess 103a is set to have
the first depth 141.
[0076] In a next step, as shown in FIGS. 18a and 18b, the handle
106 is actuated to actuate the lever 105 so that screw head 3 is
pushed into the hollow internal portion 18 of the head receiving
portion 17. The bottom of the recess 103a of the holder 103 serves
as an abutment for the receiving part, so that the head receiving
portion 17 can expand to allow the introduction of the head 3. The
handle 106 is actuated until the head 3 of the bone anchoring
element 1 is latched or inserted in the hollow internal portion 18.
The latching may produce an audible sound.
[0077] Thereafter, as shown in FIGS. 19 to 21, the holder 102 for
the bone anchoring element 1 is shifted backward and the insert 104
is moved to the second position, in which the circular recess 142
forms or defines the bottom of recess 103a to provide and use outer
surface 103b of holder 103 as an abutment for the locking ring
8.
[0078] As shown in FIGS. 20 and 21, the handle 106 is then actuated
to push the holder 102 towards the holder 103. By means of this,
the head 3 with the receiving part body 5 is pushed farther into
the recess 103a, which has a depth where the free front surface
103b of the holder 103 presses against the engagement portions 83b
of the flexible wall portions 83a of the locking ring 8, thereby
moving the locking ring 8 out of the first position into the second
position, where the engagement portions 83b are latched in the
groove 16 on the rod receiving portion 9. When the engagement
portions 83b snap into the groove 16, the latching of the locking
ring 8 with respect to the receiving part body 5 is audible, which
indicates that the correct pre-locking position is reached.
[0079] Thereafter, the holder 102 is moved backward and the bone
anchoring device is removed.
[0080] A further embodiment of a first holder 302 for the bone
anchoring element will now be described with reference to FIGS. 22
to 26. The tool 100 shown in FIG. 22 can be the same tool 100
described above, except for the first holder 302 which replaces the
first holder in the previous embodiment.
[0081] The first holder 302, shown in FIGS. 23b and 24, has a
longitudinal U-shaped recess 302a which referring to FIG. 23b,
extends from one end towards another end in a longitudinal
direction and from the side of the first holder 302 inwards. The
diameter of the recess 302a is smaller than the diameter of a head
3 of a bone anchoring element 1 in the area of a free end of the
first holder 302 facing the second holder. Therefore, a free end
surface 302b of the first holder 302 serves as an abutment for the
head 3 of the bone anchoring element 1. The first holder 302 is
supported on the frame 101.
[0082] FIG. 23a and FIG. 25 show an insert 320 for the first holder
in the form of a cylindrical section having a plurality of
longitudinally extending recesses 322a, 322b, 322c that are
arranged circumferentially around a central axis 323 of the insert
320. The recesses are sized and/or adapted for the insertion of
screws or other bone anchoring elements with different shanks. In
the embodiment shown the insert 320 has a first cylinder-shaped or
U-shaped recess 322a having a first radius, a second
cylinder-shaped or U-shaped recess 322b having a second radius and
a third cylinder-shaped or U-shaped recess 322c having a third
radius, wherein the three radii may be different from each other.
The three recesses 322a, 322b, 322c may extend the length of the
insert 320, as can be seen from FIG. 23a. The insert 320 has a
first end and a second end, wherein a first pin 321a is provided on
the first end and a second pin 321b is provided on the second end.
The pins 321a, 321b are in line with the central axis 323 of the
insert 320.
[0083] Referring to FIG. 23b, the first holder 302 has a first end
and a second end, where on the first end a first slot 311 is
provided and near the second end a second slot 312 is provided
which both extend from a side of the first holder 302 inwards. The
second end of the first holder 302 is configured to be connected to
a lever 105 and a handle 106 of the tool, as can be seen in FIG.
22.
[0084] The U-shaped recess 302a of the first holder 302 is provided
for receiving the insert 320. The radius of the circular portion of
the U-shaped recess 302a may be substantially the same as the
radius of the insert 320.
[0085] As can be seen from FIG. 24, in a mounted state, the first
pin 321a of the insert 320 fits into the first slot 311 of the
first holder 302, and the second pin 321b of the insert 320 fits
into the second slot 312 of the first holder 302. The insert 320 is
supported and guided by the pins 321a, 321b, and is also held by
the U-shaped recess 302a of the first holder 302 as can be seen in
FIG. 26.
[0086] The orientation of the first holder 302 with respect to a
second holder 103 is such that a central axis of a receiving part 5
is configured to be positioned coaxial with an axis of the bone
anchoring element 1 when the receiving part 5 is inserted into the
second holder 103 and the bone anchoring element 1 is inserted into
the first holder 302 in one of the recesses 322a, 322b or 322c of
the insert 320.
[0087] The three recesses 322a, 322b or 322c are adapted to receive
different sized shanks of bone anchoring elements. With reference
to FIGS. 22, 24, and 26, a particular recess 322a, 322b, 322c which
is in use will face outwards towards the opening of the U-shaped
recess 302a. In this embodiment of the insert 320, mounting of at
least three different sized bone anchoring elements can be
accommodated. For changing the recess 322a, 322b, 322c which is in
use, the insert 320 can be rotated around its axis 323.
[0088] In other embodiments, a cylinder or insert having more or
less than three recesses can be provided. With the second
embodiment of the holder, a user can combine screws or bone
anchoring elements with different shanks to a receiving part.
Hence, a modular system is provided that gives the user a wider
selection of implant combinations depending on the actual clinical
situation.
[0089] The bone anchoring device can be preassembled either by the
manufacturer or in the course of preparation of surgery or at any
other time. Advantageously, the surgeon can select prior to surgery
the desired receiving parts and bone anchoring elements according
to the specific requirements of the particular clinical
application. The design of the bone anchoring device allows for
selection of the appropriate bone anchoring elements in terms of
diameter, length and other features of the anchoring section.
Hence, a modular system can be provided, which includes receiving
parts and various bone anchoring elements, which then can be
individually chosen and adapted.
[0090] In use during surgery, the preassembled bone anchoring
device including the receiving part body 5, the bone anchoring
element 1 and the locking ring 8 in the pre-locking position, is
screwed into a bone. The recess 4 of the head 3 can be accessed
with a screw tool through the first bore 10. To correctly align the
receiving part body 5 with respect to the rod 6, to which it will
be connected, an additional force can be exerted onto the receiving
part, either manually or by application of an instrument. Once the
correct position of the rod 6 with respect to other bone anchoring
devices is also achieved, the inner screw 7 can be tightened for
each bone anchoring device. Since the rod 6 abuts against the
projections 86 of the locking ring 8, the locking ring 8 is shifted
downward into the third position which is the locking position.
When the locking ring 8 is moved towards the free end 17b of the
head receiving portion 17, it compresses the head receiving portion
17, thereby locking a position of the head 3. Final tightening of
the inner screw 7 locks the rod 6 and the head 3
simultaneously.
[0091] In the pre-locking condition, the head 3 remains clamped
when the inner screw 7 is loosened. This allows further adjustments
with respect to positioning of the rod 6.
[0092] Further modifications of the embodiment shown are possible.
For example, the head of the bone anchoring element can have any
other shape, for example, a cylindrical shape, whereby a monoaxial
bone screw is provided, allowing rotation of the screw element with
respect to the receiving part body around a single axis. The head
can also be conically shaped or otherwise shaped, and the internal
hollow section of the head receiving portion is adapted to
correspond to this shape. In a further modification, the
flexibility of the head receiving portion is based on properties of
the material, for example, a plastic material, and the slits may be
fully or partly omitted.
[0093] The projections of the locking ring which engage the rod can
have another shape, for example, the surface of the free end can be
flat or can be otherwise shaped. Alternatively, the projections can
be omitted.
[0094] The head receiving portion can have an inclined open end, or
can be otherwise asymmetric to allow for greater angulation of the
head in one direction.
[0095] The outer surface of the head receiving portion and the
inner surface of the locking ring can have other shapes which allow
for compression of the locking ring by means of an increasing force
when the locking ring is shifted downwards relative to the
receiving part body.
[0096] With respect to the tool, variations are also possible. For
example, the tool can be configured such that the screw axis and
the central axis of the receiving part extend perpendicular to the
surface on which the tool is placed or positioned. The holder for
the receiving part body can be movable with respect to the holder
for the bone anchoring element. In addition, instead of a manual
actuation of the tool, it may also be possible to actuate the tool
by means of a mechanically or electronically operated device.
[0097] While the present invention has been described in connection
with certain exemplary embodiments, it is to be understood that the
invention is not limited to the disclosed embodiments, but is
instead intended to cover various modifications and equivalent
arrangements included within the spirit and scope of the appended
claims, and equivalents thereof.
* * * * *