U.S. patent application number 10/999668 was filed with the patent office on 2006-06-01 for extractor for a bone connection element.
This patent application is currently assigned to Stryker Trauma SA. Invention is credited to Andre Gasser, Stefan Kugler, Christian Lutz.
Application Number | 20060116680 10/999668 |
Document ID | / |
Family ID | 36568250 |
Filed Date | 2006-06-01 |
United States Patent
Application |
20060116680 |
Kind Code |
A1 |
Kugler; Stefan ; et
al. |
June 1, 2006 |
Extractor for a bone connection element
Abstract
An extractor device is provided to extract an insert to be used
with a bone connection element such as a bone plate having at least
one opening for a bone screw used with said insert. The extractor
device has an outer hollow sleeve having proximal abutment surface
being able to engage a surface portion of the bone connection
element, and an inner bar having a diameter enabling the insertion
of the bar into the hollow sleeve. The bar has a threaded leading
end to engage the thread of the insert to be extracted. The hollow
sleeve has an inner thread and the inner bar has an outer threaded
element for engaging the inner thread of the hollow sleeve. The
outer threaded element is positioned with respect to the bar in a
longitudinal position to enable the thread at its leading end to
extend beyond the proximal abutment surface of the sleeve to be
threaded into the insert.
Inventors: |
Kugler; Stefan; (Bern,
CH) ; Gasser; Andre; (Langendorf, CH) ; Lutz;
Christian; (Solothurn, CH) |
Correspondence
Address: |
LERNER, DAVID, LITTENBERG,;KRUMHOLZ & MENTLIK
600 SOUTH AVENUE WEST
WESTFIELD
NJ
07090
US
|
Assignee: |
Stryker Trauma SA
Selzach
CH
|
Family ID: |
36568250 |
Appl. No.: |
10/999668 |
Filed: |
November 30, 2004 |
Current U.S.
Class: |
606/86B ;
606/104 |
Current CPC
Class: |
A61B 17/92 20130101;
Y10T 29/5393 20150115; A61B 17/8047 20130101 |
Class at
Publication: |
606/069 ;
606/073; 606/104 |
International
Class: |
A61F 2/30 20060101
A61F002/30 |
Claims
1. An extractor device for an insert to be used with a bone
connection element usable within an implantable orthopedic device
having a load-bearing element with at least one opening for
receiving a fixation element such as a bone screw with the insert
thereon, the extractor device comprising: an outer hollow sleeve,
the hollow sleeve comprising a introduction opening at a first end
and a proximal abutment surface at a second end engagable with a
surface portion of the load-bearing element around the insert, the
hollow sleeve further comprising an inner threaded portion between
said introduction opening and said abutment surface, an inner bar,
the bar having a diameter enabling the insertion of the bar into
said distal introduction opening of the hollow sleeve and
comprising a threaded portion engaging the thread of the insert to
be extracted, wherein, alternatively, the inner bar further
comprises an outer thread or an intermediate element is provided
with a central bore to accommodate said inner bar and comprising an
outer thread, wherein the outer threaded portion is arranged to
engage said inner threaded portion of the hollow sleeve, said outer
threaded portion of said inner bar being positioned on the bar or
the intermediate element at a longitudinal distance from the insert
engaging threaded portion to enable that threaded portion to extend
beyond the proximal abutment surface to be threaded in the
insert.
2. The extractor device as set forth in claim 1, wherein the insert
engaging threaded portion of the bar has a conical thread.
3. The extractor device as set forth in claim 1, wherein an
abutment flange connects insert engaging threaded portion with a
larger bar section of said inner bar.
4. The extractor device as set forth in claim 1, wherein the inner
bar comprises at a first end a handle part having an abutment
flange.
5. The extractor device as set forth in claim 1, wherein the hollow
sleeve comprises at its second end an enlarged abutment section to
engage a surface of the load-bearing element.
6. The extractor device as set forth in claim 5, wherein the hollow
sleeve comprises at its first end a hollow handle part.
7. The extractor device as set forth in claim 1, wherein the
threads of sleeve and bar, respectively, are located in the first
third of the device on moving from said first end of said outer
sleeve to said second end.
8. The extractor device as set forth in claim 1, wherein the
threads of sleeve and bar or intermediate element have the same
handedness than the thread of the tip of the inner bar.
9. The extractor device as set forth in claim 1, wherein the
abutment surface is a cylindrical ring, an elliptical ring or a
polygonal strip.
10. A method for extracting an internally threaded insert from an
opening in a bone connection element usable within an implantable
orthopedic device, such as a bone plate: inserting a bar with a
threaded tip and an outer threading into a hollow sleeve having an
internal threading for engaging the outer threading of the bar and
an abutment tip for engaging the bone plate; screwing the tip of
the bar into the internal threading of the insert to be extracted,
preferably until an abutment flange of the tip comes into contact
with an upper surface of the insert, advancing the abutment tip of
the hollow sleeve into contact with a surface of the bone
connection element, wherein the relative advancement of the hollow
sleeve relative to the bar is a longitudinal movement resulting
from rotating the engaged inner and outer threads of sleeve and
bar; extracting the insert through further rotation of sleeve or an
intermediate element located between the sleeve and the bar,
wherein the inner bar or the sleeve, respectively, are maintained
in its rotational position, said rotation retracting the bar into
the hollow sleeve and exerting a force in a longitudinal direction
of the sleeve and bar on the insert against forces holding the
insert within the opening in the bone connection element and
extracting the insert.
11. The method as set forth in claim 10, wherein the extractor
device is assembled by inserting the inner bar into the hollow
sleeve from an opening at a first end of the hollow sleeve and
relative rotation of the hollow sleeve and bar to engage their
inner and outer threads, respectively, until the tip of the bar is
extends beyond a second end of the hollow sleeve.
12. An extraction tool for an internally threaded insert located
within an opening in a bone plate comprising: a tubular sleeve
having an internal bore with a threaded portion intermediate first
and second ends thereof; a bar for insertion within the internal
bore of said tubular sleeve, said bar having a threaded first end
and a threaded element located intermediate said first end and a
second end of said bar, said threaded element threadably engagable
with said threaded outer sleeve portion, said threaded sleeve
portion and said threaded element respectively located between the
first and second ends of said sleeve and bar such that said
threaded first end of said bar extends beyond said first sleeve end
when at least a portion of said threaded portions are engaged.
13. The extraction tool of claim 12 wherein the first end of said
tubular sleeve includes an abutment portion.
14. The extraction tool of claim 13 wherein said second end of said
tubular sleeve has a drive portion for rotating said sleeve.
15. The extraction tool of claim 14 wherein said second end of said
bar has a drive portion for rotating said bar.
16. An insertion device for use with an insert to be used with a
bone connection element usable within an implantable orthopedic
device, the insert having at least one threaded opening for a
fixation element, the insert having inwardly deformable sidewalls
for engaging walls of said opening, the insertion device
comprising: a bar having a threaded portion at one end thereof to
engage the thread in the opening of the insert to be inserted,
wherein a length of the threaded end portion of said inner bar is
shorter than a thickness of the insert to avoid engagement of the
threaded bar portion with the deformable sidewalls of said
insert.
17. An insert for use with an orthopaedic device such as a bone
plate with at least one opening for receiving a fixation element
engagable with said insert, the insert comprising an external
surface that is at least partially complementary to an internal
shape of the opening, wherein the insert has a central threaded
through-bore for mounting a body of the fixation element, and in
which the insert has resilient sidewalls for holding the insert in
the opening which sidewalls have a thickened part which can be
positioned adjacent an internal portion of said opening.
18. The insert as set forth in claim 17 wherein said thickened part
tapers inwardly towards said through-bore.
Description
BACKGROUND
[0001] The invention concerns an extractor device for an insert to
be used with a bone connection element usable within an implantable
orthopedic device having a load-bearing element such as a bone
plate with at least one opening for a fixation element such as a
bone screw. A screw can be used such as shown in the application
entitled "Self-Guiding Threaded Fastener" with inventor Yves Crozet
filed on Nov. 30, 2004 the entire disclosure of which is
incorporated herein by reference. The invention is furthermore
related to the insert itself and to an insertion device for such an
insert. The inserts may be used in bone plating systems such as
described in the application entitled "Bone Plating Implants,
Instruments and Methods" filed Nov. 30, 2004 listing Yves Crozet,
Christian Lutz and Renee Wirth as inventors the disclosure of which
is hereby incorporated by reference.
[0002] Such an insert is provided that can be inserted into the
opening in a receptacle in which the external shape of the insert
is at least partially complementary to the internal shape of the
receptacle. The insert has a central through-bore for mounting a
body of the fixation element. The implantable orthopedic device has
a structure for holding the insert in the receptacle.
[0003] A series of implantable orthopedic devices with load-bearing
elements, such as bone plates, with openings for the insertion of
fixation elements in such load-bearers are known from the prior
art. Among them are proposals for the mono-axial as well as
poly-axial attachment of fixation elements, particularly
screws.
[0004] As an example for a device of this type having poly-axial
attachment of screws in load-bearing elements is shown in U.S. Pat.
No. 5,954,722. Other bone plates with inserts are shown in U.S.
Pat. Nos. 5,269,784, 5,976,141 and 5,607,428. One advantageous
insert is shown in WO 2004/082493, which is hereby incorporated by
reference.
[0005] FIG. 1 OF WO 2004/082493 shows a perspective view of an
insert to be used with a load-bearing element such as a bone plate.
FIG. 2 is a sectional side view of a load-bearing element with
another insert inserted. The load-bearing elements can be equipped
in advance with standard inserts. This enables an easier more cost
efficient production of bone plates giving the surgeon the
possibility to adapt the bone plate according to his needs. A
surgeon thus may turn an opening in a bone plate adapted to receive
a non-locking screw to an aperture in which a locking screw having
a threaded portion adapted to threadably engage the plate via the
insert can be used. Then it may sometimes be necessary to extract
one or the other insert and to replace it by another different
insert or to leave the bore or opening empty. The prior art
exhibits the disadvantage that there are no extracting tools
provided to help the surgeon team to extract inserts.
SUMMARY OF THE INVENTION
[0006] It is therefore one aspect of the invention to provide an
extractor device allowing to extract easily different inserts from
different load-bearing elements.
[0007] This aspect is fulfilled according to the invention for an
extractor device of the aforementioned type which can easily remove
an insert from a bone plate opening so that it may receive a
non-locking screw.
[0008] This object is achieved by an extractor device, which can
engage the insert in a manner that enables the extraction of the
said insert from the load-bearing element in a simple and swift
movement. The extraction can be accomplished for quite a number of
different inserts, with different angled positions. Of particular
advantage is that the secure extraction of the insert can be
assured directly and automatically with the use of the extractor
device.
[0009] One single extractor device is sufficient to provide the
necessary help to extract various inserts with inclined axes as
long as the inner bore has a predefined thread. The surgeon can
therefore use a bone plate with inserts with predefined angles for
the insertion of poly- or monoaxial screws and change one or more
of the inserts to orient bone screws at a number of different
defined angles in a simple manner.
[0010] It is another aspect of the invention to provide an insert,
which is easy to handle for the surgeon.
[0011] It is furthermore an aspect of the invention to provide an
insertion device allowing a simple insertion of different inserts
into different load-bearing elements.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The present invention will be better understood on reading
the following detailed description of non-limiting embodiments
thereof, and on examining the accompanying drawings, in which:
[0013] FIG. 1 is a top view of a load-bearing element in the form
of a bone plate with a row of attachment bores;
[0014] FIG. 2 is a perspective view of a first insert to be used
with a load-bearing element;
[0015] FIG. 3 is a sectional side view of a load-bearing element
with a second insert inserted;
[0016] FIG. 4 is a perspective view of an extractor device
according to one embodiment of the invention;
[0017] FIG. 5 is a side view of the device according to FIG. 4;
[0018] FIG. 6 is a sectional side view of the external sleeve of
the extractor device according to FIG. 4;
[0019] FIG. 7 is a perspective view of the inner bar of the
extractor device according to FIG. 4;
[0020] FIG. 8 is a sectional side view of the inner bar of FIG.
7;
[0021] FIG. 9 is an enlarged view of the tip of the inner bar of
FIG. 7;
[0022] FIG. 10 is a sectional side view of an extractor device
according to a second embodiment of the invention in vicinity of an
load-bearing element;
[0023] FIG. 11 is a side view of an insertion device according to
an embodiment of the invention;
[0024] FIG. 12 is an detail of the tip of the insertion device
according to FIG. 11;
[0025] FIG. 13 is a perspective view of a second insert to be used
with a load-bearing element;
[0026] FIG. 14 is a sectional side view of the insert according to
FIG. 13; and
[0027] FIG. 15 is an enlarged side view showing a detail of the
insert according to FIG. 13.
DETAILED DESCRIPTION
[0028] Referring to FIG. 1 there is shown a top view of a
load-bearing element in the form of a plate 1 with a row of
attachment bores 2 arranged along the longitudinal direction of
plate 1. FIG. 2 shows a perspective view of a first insert 10 to be
used with a load-bearing element 1. Bores 2 of plate 1 are
through-bores that exhibit an oval central opening 3. At opening 3
there are two sidewalls 5 on opposite sides of axis 4, which extend
parallel to the direction of longitudinal axis 4 of plate 1 and
extend at right angles to the surfaces of the plate. These parallel
sidewalls 5 are connected on both ends by semicircular walls 6,
each forming a semi-cylindrical boundary so that together the
aforementioned oval opening 3 results.
[0029] In other forms of the plate, oval bores 2 can also be
provided. Bores 2 can also be elliptical or of a common elongated
form. What is essential is the multiplicity of functions for the
selection of attachment elements or fasteners made possible by
insert 10 shown in FIG. 2. Through the mostly elongated form of
plate 1, elongated bores 2 are preferred over circular bores in
order to maintain flexibility with the insertion of screws with
larger diameters. The bore may also be essentially cylindrical with
the disadvantage that the insert 10 has less material for providing
inclined holes in the insert 10.
[0030] Arranged around the cylindrical, not necessarily circular
walls 5, 6 forming opening 3 is chamfered surface area 7, extending
and tapering inwardly from the upper surface 8 of plate 1 that
faces away from the bone during implantation. The form of this area
7 is preferably part-spherical.
[0031] The top surface 8 of load-bearing element 1 is formed
somewhat deeper in the side area 18 near bores 2. The same is true
for upper edge 15 of sidewall 5, which are shown to be lower
(closer to the plate bottom surface) in a direction opposite the
bore ends in longitudinal direction 4. Bottom surface 9, which is
closest to the bone in insertion during surgery is here locally
flat. Normally, plates 1 can exhibit continuous surfaces 8 and
undersurfaces 9 which at each point, for the function of
positioning on the bone can always be considered to be flat. But
here too, positioning on curved or bent surfaces can be
provided.
[0032] FIG. 2 shows a perspective view of an insert 10 to be used
with a load-bearing element 1 according to FIG. 1. Similar
characteristics appear in all figures with the same reference
numerals. Each insert 10 is designed to be shaped complementary to
bore 2 for locking therein with respect to areas 7 and sidewalls 5.
Insert 10 has a central bore 11 with an internal threading 12.
Internal threading 12 can be cylindrical or slightly conical.
Insert 10 can have an area that extends beyond lower surface 9 of
plate 1 that is adjacent the bone. In particular, insert 10 has
locking mechanisms along its edges. In particular, the locking
mechanism can be two projecting rims that engage the underside 9 of
plate 1 after the insertion of insert 10. The insert 10, when it is
inserted into plate 1, with its extension area, can form a distance
spacer with regard to the bone material into which a screw that has
been inserted into bore 11 is turned.
[0033] It is also possible that, at least along the length of the
longitudinal axis 4 of the load-bearing element 1, a recess 33 is
provided on the bottom surface 9 around opening 2 of the plate 1.
This recess can also be provided on the narrow side. In addition,
insert 10 is provided with a projecting rim 27 that is arranged in
such a way that the bottom of insert 10 does not project beyond
lower surface 9. The underside of insert 10 is thus at least flush
with the aforementioned surface 9 of the load-bearing element
1.
[0034] The reference numeral 21 refers to the surface of insert 10
having a circumference 22 that meets with the edge of area 8 of
plate 1. A spherical surface 23 extends downwardly from surface 21
and is shaped so as to have complementary surface contact with
surface 7. Semicircular extension 24 extends downwardly from
surface 23 and is in conforming contact, without any significant
play, with area 6 of bore 2.
[0035] The area lying opposite the longitudinal surface 5 consists
of a resilient extension 25 on each side, in which, in the
preferred embodiment shown, each extension 25 is provided with
slots 26. Each extension 25 has, on its lower edge, a projecting
rim 27 facing outward from the point of view of the insert with an
upward-facing shoulder 28 with an outer edge 29. The surface of rim
27 that is facing toward the bone can be inclined. Extension 25 is
also to a certain extent, flexible. In inserting insert 10,
extension 25 then slides into bore 2 and is deflected inwardly by
the projecting rim 27. Once insert 10 is completely inserted,
shoulder 28 slides against underside 9 of plate 1 and locks insert
10 in plate 1. This locking is additionally ensured by the
subsequent insertion of a bone screw (not shown). FIGS. 13 thru 15
show a slightly modified insert having tapered side elements or
sidewalls 25a which taper inwardly from their free edges 127 to
surface 23a. The insert will be described in more detail below.
[0036] It is one aspect of the invention to provide an extractor
device being able to extract such a fixed insert 10 from the plate
1. Pressure has to be exerted in such a way that an inward
deflection of extension 25, 25a is obtained so that projecting rim
27, 127 is no longer secured under plate 1 or in a recess provided
at the bottom of the plate 1. It should be noted that the extractor
device has to also function if extension 25, and with it projecting
rim 27, are not arranged as two extensions 25 on the opposing
longer sides of insert 10. The design can also include resilient
extensions on the narrow sides of an insert, i.e. corresponding to
the location of the semicircular cylindrical extensions 24.
Extensions 25 can also be arranged in an alternating manner. There
can also be only one or two more extensions.
[0037] Referring to FIG. 4 there is shown a perspective view of an
extractor device 50 according to a preferred embodiment of the
invention. Extractor device 50 comprises two different parts, an
outer sleeve 60 and an inner bar 70 extending on both sides beyond
the through going bore or cannulation inside the sleeve 60. The
outer sleeve 60 is shown in greater detail in FIG. 6, the inner bar
70 is shown in greater detail in FIG. 7 to 9.
[0038] FIG. 5 shows a side view of the device 50 according to FIG.
4. The outer sleeve 60 comprises a hollow sleeve part 61 having a
first handle part 62 being an integral part of the sleeve 60. The
first handle part 62 comprises a circumferential depression 65 to
provide a grip portion for the hand of a user of the device 50. A
thickened abutment sleeve 63 is provided on the opposite end of the
hollow sleeve part 61 ending in a round abutment ring 64 having a
larger diameter than the diameter of the proximal bar section 73 of
the inner bar 70. The function of the abutment ring 64 will be
explained below. The length of the external sleeve 60 can be
between 150 and 200 millimeter with a first handle part 62 diameter
of 30 to 50 millimeter and a outer sleeve diameter of e.g. 14
millimeter.
[0039] It can be seen from both, FIGS. 4 and 5 that the preferred
inner bar 70 extends beyond both ends of outer sleeve 60. On the
side of the first handle part 62 the inner bar 70 comprises a
second handle part 72 having a circumferential gripping depression
75. The radius of the second handle part 72 is greater than the
inner diameter of the hollow sleeve 60. An engagement thread 71 is
provided at the end of the proximal bar section 73 extending beyond
the hollow sleeve 60.
[0040] FIG. 6 shows a sectional side view of the preferred external
sleeve 60 of extractor device 50 according to FIG. 4. The hollow
sleeve comprises a through-bore extending along axis 82a with a
middle section 66 having a first diameter and extending from the
opening 67 at the distal end near the first handle part 62 towards
an internal thread 68. The through-bore comprises on its proximal
end 69 a second diameter being smaller than the above-mentioned
first inner diameter. The internal thread 68 can have a length of
e.g. 10 millimeter with 5 to 10 full threads. The internal thread
68 is positioned near the proximal end of the sleeve 60, e.g.
between 20 and 40 millimeter from the abutment ring 64. It would
also be possible to locate the internal thread 68 near or under the
first handle part 62.
[0041] The first inner diameter, being the inner diameter of a part
of the sleeve 60, can be chosen to be 12 Millimeter, said second
diameter of the end portion 69 can be chosen to be 11 millimeter.
The enlarged section 63 can have a diameter of 14 millimeter.
[0042] FIG. 7 shows a perspective view of the preferred inner bar
70 of the extractor device 50 according to FIG. 4. FIG. 8 shows a
sectional side view of the inner bar 70 of FIG. 7. The inner bar 70
comprises a first distal bar portion 74 having an outer diameter
similar to the first inner diameter of the hollow sleeve 60 so that
the bar 70 can be inserted with little play into the hollow sleeve
60 from the side of the opening 67. The distal bar portion 74 ends
in an abutment flange 76 of the gripping depression 75. On the
opposite end of the distal bar portion 74 a middle bar portion 77
has a thinner cylindrical portion. The middle bar portion 77 is
followed, by a threaded portion 78 having a longitudinal length
which is preferably identical to the inner threaded portion 68 of
the outer sleeve 60. The location of thread 78 also depends on the
location of the inner threaded portion 68. If portion 68 is located
near or under the first handle part 62 then the threaded portion 78
of the inner bar 70 is located near or in the area of the distal
bar portion 74.
[0043] In the embodiment shown in the drawings, the threaded
portion 78 is proximally followed by the proximal inner bar section
73. Inner bar section 73 is followed by a tip portion 71 of the
inner bar 70, which is shown in FIG. 9 in an enlarged view.
[0044] The tip portion 71 preferably comprises four full threads of
a thread 80 ending in a flat surface 81. In the preferred
embodiment the thread 80 is conical and is connected with the inner
bar section 73 via a chamfered flange 79. The direction of the
threading 80 is identical to the direction of the thread 78. The
main axis 82 of the bar 70 coincides with the axis 82 of the thread
80 and with the longitudinal main axis 82a of the sleeve 60. The
advantage of a conical thread 80 is the easier fixation of the bar
onto inserts 10 with damaged threads 12.
[0045] The function of the device 50 is as follows. The device is
assembled through insertion of the bar 70 into the hollow sleeve 60
through the distal opening 67 within the sleeve 60 such that axis
82, 82a and coaxial. The thread 78 of the bar 70 engages the inner
thread 68 of the hollow sleeve 60 and is rotated until the tip 71
is extending beyond the end of the hollow shaft 60 or until the
threads 68 and 78 come free one from the other. Both threads 68 and
79 are right-handed, i.e. the thread 78 advances when turned
clockwise with respect to its mating part 68. The flange 76 of the
second handle part 72 can ultimately abut against the first handle
part 62 of the hollow sleeve 60. The thread 78 may then no longer
be in engagement with thread 68.
[0046] The bar 70 is then screwed into the insert 10 by turning the
handle 72, i.e. the conical thread 80 is engaging the internal
threading 12 of the insert 10. Preferably the abutment flange 79 of
the tip is coming into contact with the upper surface 21 of the
insert 10. Then the abutment ring 64 is advanced to come into
contact with the surface 8 of the plate 1 beside the insert 10,
i.e. the abutment ring 64 does not contact surface 21 but touches
the plate 1 outside the circumference 21 of the insert 10. This
contact is possible independent from the angle and direction of the
insert bore 11 as discussed above. The relative advancement of
sleeve 60 in relation to the bar 70 can be a longitudinal movement
or comprising a rotation when the threads 68 and 78 come into
engagement. For a rotational movement the handle part 62 is rotated
against the handle part 72 of the inner bar, which is maintained in
its position. The internal thread 12 of the insert 10 is also
right-handed.
[0047] When the abutment ring 64 comes in contact with the upper
surface 8 of the plate 1 (and not with the insert 10), then the
extractor sleeve 60 is further rotated in the direction opposite to
the above mentioned rotation of the bar 70. This rotation retracts
the rod 73 further into the sleeve 60 and therefore exerts a force
in the longitudinal direction of axis 82 of the extractor device 50
on the insert 10 against the plate 1. This leads to the situation
that engagement means 25 of the insert 10 are overcome and the
insert 10 will be extracted. The advantage of right-handed threads
68 and 78 resides in the fact that the rotation to extract the
insert 10 additionally blocks the thread 12 of the insert 10 in
thread 80 of the tip 71.
[0048] In another embodiment (not shown) the threads 68 and 78 may
be left-handed. Then the surgeon has the usual anti-clockwise
movement to extract the insert; however, it is then possible that
the thread 12 of the insert 10 becomes no longer fastened to the
conical thread 80 of the inner bar 70.
[0049] It is clear that the abutment ring 64 can be of a different
form than having a circular shape. It may have a polygonal abutment
surface or the plane of the abutment surface can comprise an angle
with the plane perpendicular to the longitudinal direction of axis
82 of the bar 70.
[0050] FIG. 10 shows a sectional side view of an extractor device
90 according to a second embodiment of the invention in vicinity of
an load-bearing element 1. Extractor device 90 comprises three
different parts, an outer sleeve 60 and an inner bar 70 extending
on both sides beyond the through going bore inside the sleeve 60.
Additionally there is an intermediate element 91 essential to the
function of the device.
[0051] The outer sleeve 60 comprises a hollow sleeve part 61 having
a first handle part 62 being an integral part of the sleeve 60. The
first handle part 62 comprises a circumferential depression 65 to
provide a grip portion for the hand of a user of the device 50. A
thickened abutment sleeve 63 is provided on the opposite end of the
hollow sleeve part 61 ending in a round abutment ring 64 having a
larger diameter than the diameter of the proximal bar section 73 of
the inner bar 70. The function of the abutment ring 64 is identical
as explained above.
[0052] The inner bar 70 extends on both sides of outer sleeve 60.
On the side of the first handle part 62 the inner bar 70 comprises
a second handle part 72 having a circumferential gripping
depression 75. Between the two handle parts 62 and 72 the
intermediate element 91 is introduced.
[0053] The intermediate element 91 has a through bore 93 for the
inner bar 70. The intermediate element 91 comprises a grip portion
92 being able to be in abutment against the handle part 72 of inner
bar 70 on one side and with the handle part 62 of the sleeve 60 on
the other side. On the side of the handle part 72 the intermediate
element 91 comprises an opening 97 in the flat upper surface to
receive the inner bar 70. On the side of the handle part 62 the
intermediate element 91 comprises a smaller central projection 94
with an external thread 98.
[0054] Sleeve 60 incorporates in the handle part 62 a recess 95 to
accommodate the projection 94, wherein the recess 95 comprises an
internal thread 108.
[0055] As in the first embodiment of an extractor device 50, an
engagement thread 71 is provided at the leading end of the proximal
bar section 73 extending beyond the hollow sleeve 60.
[0056] Inner bar 70 of the extractor device 90 comprises a bar
portion 74 having an outer diameter similar to the inner diameter
of the hollow sleeve 60 and similar to the inner diameter of the
intermediate element 91 so that the bar 70 can be inserted with
little play into the intermediate element 91 and into the hollow
sleeve 60 from the side of the openings 67 and 97. The bar portion
74 ends in an abutment flange 76 of the gripping depression 75.
[0057] The tip portion 71 of extractor device 90 can be the same as
the tip portion 71 of extractor device 50.
[0058] The function of the device 90 is as follows. The device is
assembled through insertion of the intermediate element 91 into the
hollow sleeve 60 through the opening 67 within the sleeve 60. The
thread 98 of the intermediate element 91 engages the inner thread
108 of the hollow sleeve 60 and is rotated until the handle part 92
abuts against the handle part 62 or the projection 94 reaches the
depth of the recess 95. Both threads 98 and 108 are right-handed.
The bar 70 is then entered into intermediate element 91 and hollow
sleeve 60 and screwed into the insert 10 by turning the handle 72,
i.e. the conical thread 80 is engaging the internal threading 12 of
the insert 10. Then the abutment ring 64 is advanced to come into
contact with the surface 8 of the plate 1 beside the insert 10,
i.e. the abutment ring 64 does not contact surface 21 but touches
the plate 1 outside the circumference 21 of the insert 10.
[0059] The handle part 92 of the intermediate element 91 is rotated
against the handle part 62 of the hollow sleeve 60, which is
maintained in its position. As rotation occurs, the intermediate
element 91 and the hollow sleeve 60 move apart, while the inner bar
70 just follows, because the handle part 72 is in abutment with the
intermediate element 91. The rotation of intermediate element 91
indirectly retracts the rod 73 further into the sleeve 60 and
therefore exerts a force in the longitudinal direction of said axis
82 of the extractor device 90 on the insert 10 against the plate 1.
This leads to the situation that engagement means 25 of the insert
10 are overcome and the insert 10 will be extracted. In the case of
the second embodiment it is advantageous to use right-handed
threads 80 and 12 whereas threads 98 and 108 are left-handed. Then
the rotation to extract the insert 10 blocks the insert 10 in
thread 80 of tip 71.
[0060] However in all embodiments it is possible to switch the
handedness of any pair of threads.
[0061] Upon extraction of an insert 10, the insert 10 either
completely or nearly disappears within the hollow thickened
abutment sleeve 63.
[0062] FIG. 11 shows a side view of an insertion device 100
according to an embodiment of the invention and FIG. 12 is an
detail of the tip of the insertion device 100 according to FIG. 11.
Insertion device 100 is very similar to inner bar 70, having a bar
101 with a handle part 102 at one end, whereas the other free end
of the bar 101 comprises a cylindrical tip 103 with a smaller
diameter than the bar 102. Said tip 103 comprises one single thread
105 and ends with a flat bottom surface 104, which can be chamfered
for easier insertion. Tip 103 is positioned within the opening of
an insert 10 and the thread 105 engages the complementary thread 12
of the insert 10. It is clear that due to the shortness of the tip
103 the resilient extensions 25 of insert 10 are not in the
vicinity of the tip 103 but spaced apart in the longitudinal
direction of axis 82b of the insertion tool 100. It is possible
that the distance between the thread 12 and the upper surface 21 of
the insert 10 is such that said surface 21 can abut against the
abutment flange 109 of the bar 101.
[0063] Initially the insert 10, 20 to be inserted into a plate 1 is
affixed to the insertion device 100 as mentioned above. Then the
device 100 with the insert 10, 20 at its tip is pushed against and
into the plate 1 until the locking extensions 25 of the insert 10,
20 are pushed beyond the smallest waist part, i.e. the smallest
diameter in the hole 2 of a plate 1. Then the insertion device 100
can be rotated in the opposite direction to free the insert 10, 20
from its tip. This can be done directly, because the inserts 10, 20
are oblong.
[0064] FIG. 13 shows a perspective view of a second insert 110 to
be used with a load-bearing element 1. FIG. 14 is a sectional side
view of the insert 110 according to FIG. 13 and FIG. 15 is an
enlarged side view showing a detail of the resilient extension 25a
of the insert according to FIG. 13. Insert 110 comprises a flat
upper surface 121 at its circumference wherein on the inside of
surface 121 a step-like recess 122 is provided. The resilient
extension 25a on each side is separated as within the embodiment
according to FIG. 1 from the semicircular extensions 24a by two
slots 26a. The resilient extension 25a comprises a special
triangular form when seen from the side or in a cross section.
[0065] On the inside the resilient extension 25a comprises the
inner thread 12 which can be oriented in different ways and angles.
On the outside the insert 110 has a waist 129, i.e. an area with
minimum exterior diameter. Towards the upper side 121 of the insert
110 there is the larger spherical surface 23a or another
complementary surface for the bore 2 in plate 1. Towards the bottom
side there is provided, on the resilient extensions 25a, a
thickened region 127. In the embodiment shown the thickened region
127 has a thickest part near the lower end of the extension 25a,
i.e. the cross section through the extension 25a always shows a
triangle form. Advantageously the form of the plate 1 is
complementary, i.e. the plate has at least on its sides a recess to
accommodate the thickened region 127. The chamfered lower end 128
facilitates the introduction of the insert 110 into a plate 1. The
angle of the surface 128 in relation to the bottom surface is 120
degree (reference numeral 124). The triangle form 127 also
facilitates the extraction of the insert 110 because the inclined
surface 126, e.g. with an angle of 30 degree to the vertical axis
of the insert 110, can slide on the complementary inclined surface
of the plate 1 or on the smallest internal diameter of hole 2
thereof.
[0066] Although the described drawings already show a whole series
of possible configurations of the invention, the invention is and
should be limited only by the parameters of the attached
claims.
[0067] The advantage of the invention is that it offers the surgeon
using a plate 1 with conventional standard bores 2 and inserted
inserts 10, 110 the possibility of adapting the plurality of
angularly-stable mono-axial bores by replacement of inserts, and
furthermore, that this is made possible intra-operatively.
* * * * *