U.S. patent application number 10/095544 was filed with the patent office on 2002-07-11 for device for fixing a rod to a thin bone wall.
Invention is credited to Faure, Alexis.
Application Number | 20020091389 10/095544 |
Document ID | / |
Family ID | 9512161 |
Filed Date | 2002-07-11 |
United States Patent
Application |
20020091389 |
Kind Code |
A1 |
Faure, Alexis |
July 11, 2002 |
Device for fixing a rod to a thin bone wall
Abstract
The invention concerns an implantable device for fixing a rod in
a rather thin bone wall comprising two parts, each comprising a
body with a passage for receiving the rod, and a curved hook
extending laterally relative to the body. Each hook is shaped such
that the two hooks facing each other can be simultaneously
inserted, by mutually titling the two parts urging their bodies
closer to each other, in an opening arranged in the wall, and be
mutually spaced rearwards as said bodies are brought closer to each
other. The rod received in said passages of the two bodies is
capable of preventing any reverse tilting of said parts. The
invention is particularly useful for fixing a rod for backbone
osteosynthesis in the flat part of the skull occipital bone.
Inventors: |
Faure, Alexis; (Nantes,
FR) |
Correspondence
Address: |
LERNER, DAVID, LITTENBERG,
KRUMHOLZ & MENTLIK
600 SOUTH AVENUE WEST
WESTFIELD
NJ
07090
US
|
Family ID: |
9512161 |
Appl. No.: |
10/095544 |
Filed: |
March 12, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10095544 |
Mar 12, 2002 |
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09529450 |
Jun 13, 2000 |
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6375656 |
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09529450 |
Jun 13, 2000 |
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PCT/FR98/02178 |
Oct 12, 1998 |
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Current U.S.
Class: |
606/276 ;
606/330 |
Current CPC
Class: |
A61B 17/7056 20130101;
A61B 17/7055 20130101 |
Class at
Publication: |
606/61 |
International
Class: |
A61B 017/56 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 13, 1997 |
FR |
97/12776 |
Claims
1. An implantable device for fixing a rod to a thin bone wall, in
particular for fixing a rod of a system for osteosynthesis of the
spine to the wall of the occipital bone of the skull, the device
comprising a rod and first and second parts each of said first and
second parts comprising both a body in which there is formed a
passage for receiving the rod, and also a curved hook extending
laterally relative to the body, each hook is of a shape such that
the two hooks when placed face to face can be inserted
simultaneously into an opening formed in said bone wall, the hooks
being inserted by tilting the two parts in opposite directions so
as to tend to move their bodies towards each other, the hooks
moving away from each other behind said wall as said bodies move
towards each other, and in that said passages of the two bodies
come into alignment once the bodies have come together with the
parts in mutual contact, and the rod is suitable for being received
therein, thereby preventing said parts from tilting in the opposite
direction.
2. The device according to claim 1, wherein the body of each part
is generally oval in shape with at least one plane face, and in
that said bodies are suitable for being placed essentially in
contact with each other via their face plane faces so as to ensure
that both passages are in axial alignment.
3. The device according to claim 2, wherein each hook has a root
region extending from the vicinity of said plane face, essentially
at right angles relative to the axis of the passage, and an end
portion extending substantially parallel to the axis of the
passage.
4. The device according to claim 3, wherein the overall size of
each hook as measured in a direction parallel to the axis of the
corresponding passage is greater than the thickness of the body in
said direction.
5. The device according to claim 4, wherein the body has a second
plane face substantially parallel to the first plane face.
6. The device according to claim 1, wherein each hook is of a
thickness that tapers progressively away from its root portion
towards its free end.
7. The device according to claim 1, wherein each hook is of a width
that is substantially constant over its entire extent.
8. The device according to claim 1, wherein each part includes
means for locking the rod in its passage.
9. The device according to claim 8, wherein the locking means
comprise a screw engaged in tapping formed in the body and opening
out into the passage.
10. The device according to claim 1, wherein the two parts are
identical.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. Ser. No. 09/529,450
filed Jun. 13, 2000.
BACKGROUND OF THE INVENTION
[0002] The present invention relates in general to an implantable
device for occipital fixing, and in particular to a device designed
to fix a patient's occipital bone to the end of a system for
osteosynthesis of the spine and having longitudinal rods.
[0003] Rod systems for osteosynthesis of the spine are well known.
They comprise two rods that are generally cylindrical and that are
secured to respective sides of the vertebrae by means of screws
and/or hooks.
[0004] Although such fixings are entirely suitable for securing the
vertebrae, it is necessary to design special fixings when such a
system needs to be extended to the skull, more precisely to the
occipital bone.
[0005] The present invention seeks to propose a device for
anchoring in a bone wall of relatively small thickness and suitable
for use in fixing rods of an osteosynthesis system for the spinal
column to the occipital bone, which device provides satisfactory
mechanical strength, while being simple to make and implement, and
minimizing the need for holes to be made through said bone
wall.
SUMMARY OF THE INVENTION
[0006] Thus, the present invention provides an implantable device
for fixing a rod to a thin bone wall, in particular for fixing a
rod of a system for osteosynthesis of the spine to the wall of the
occipital bone of the skull, the device being characterized in that
it comprises two parts each comprising both a body in which there
is formed a passage for receiving the rod, and also a curved hook
extending laterally relative to the body, in that each hook is of a
shape such that the two hooks when placed face to face can be
inserted simultaneously into an opening formed in the bone wall,
the hooks being inserted by tilting the two parts in opposite
directions so as to tend to move their bodies towards each other,
the hooks moving away from one another behind the wall as the
bodies move towards each other, and in that the passages of the two
bodies come into alignment once the bodies have come close
together, and the rod received therein is suitable for preventing
the parts from tilting in the opposite direction.
[0007] Preferred but non-limiting features of the device of the
invention are as follows:
[0008] the body of each part is generally oval in shape with at
least one plane face, and the bodies are suitable for being placed
essentially in contact with each other via their facing plane faces
so as to ensure that both passages are in axial alignment
[0009] each hook has a root region extending from the vicinity of
the plane face, essentially at right angles relative to the axis of
the passage, and an end portion extending substantially parallel to
the axis of the passage;
[0010] the overall size of each hook as measured in a direction
parallel to the axis of the corresponding passage is greater than
the thickness of the body in the direction;
[0011] the body has a second plane face substantially parallel to
the first plane face;
[0012] each hook is of a thickness that tapers progressively away
from its root portion towards its free end;
[0013] each hook is of a width that is substantially constant over
its entire extent;
[0014] each part includes means for locking the rod in its
passage;
[0015] the locking means comprise a screw engaged in tapping formed
in the body and opening out into the passage; and
[0016] the two parts are identical.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Other aspects, objects, and advantages of the present
invention will appear more clearly on reading the following
description of a presently preferred embodiment of the invention
given by way of example and described with reference to the
accompanying drawing, in which:
[0018] FIG. 1 is a view of the occipital bone of a patient seen
from outside the skull;
[0019] FIGS. 2a to 2c are side views in perspective of two anchor
elements of an occipital fixing device of the invention during
three successive stages of the process of installing them; and
[0020] FIG. 3 is a perspective view of the device of the invention
seen from inside the posterior cranial fossa defined by the
occipital bone.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] With reference initially to FIG. 1, there is shown the
region of the occipital bone EO of a patient.
[0022] Using a trepan, the surgeon has made two generally circular
holes therein referenced T, which holes are of determined diameter
and are spaced apart laterally by a determined distance.
[0023] With reference now to FIGS. 2a to 2c and 3, a fixing device
of the invention comprises two identical parts 10, 10. Each part
comprises a generally oval-shaped body 11 having generally plane
opposite faces with a through cylindrical bore 12 of well
determined diameter made therethrough.
[0024] The body is extended laterally by a hook-forming portion 13
having a root portion that extends substantially at right angles
relative to the axis of the bore 12 close to one of the plane faces
of the body 11, said root portion being extended in curved manner
so as terminate substantially parallel to said axis, beyond the
other plane face of the body.
[0025] Advantageously, the width of the hook 13 is essentially
constant, and slightly smaller than the outside diameter of the
body 11, and it tapers progressively towards its free end.
[0026] As can be seen in particular in FIG. 3, the hook 13 has a
free end that is slightly rounded.
[0027] The device comprising two parts 10, 10 is put into placed as
described below with reference to FIGS. 2a to 2c.
[0028] In FIG. 2a, it can be seen that the two parts 10, 10 are
positioned facing each other in such a manner that the end regions
of the hooks 13 are adjacent and point into the hole T, penetrating
a little therein. This can be achieved by giving overall dimensions
to the hooks 13 as measured parallel to the axes of the respective
bores 12 that are greater than the thickness of the body 11 between
its two opposite plane faces.
[0029] It will be observed at this point that the diameter of the
hole T is selected in such a manner that in this position the ends
of the hooks 13 can be engaged side by side in the hole T by
appropriately tilting the two parts 10, 10 in opposite directions.
An intermediate stage in this tilting is shown in FIG. 2b, where it
can be seen that the hooks have begun to engage in the posterior
cranial fossa, moving laterally away from each other so that the
distance between the free ends thereof becomes greater than the
diameter of the hole T.
[0030] This tilting movement is continued until the bodies 11 of
the two parts 10, 10 are side by side and their hook-forming
portions 13 are in a hooking relationship with the wall of the
occipital bone. It will be understood that to achieve this hooking,
the overall length of each hook 13 as measured in a direction
parallel to the axis of the bore 12, must be greater than the
radius of the hole T formed through the occipital bone.
[0031] At this stage, it will be observed that the device
constituted by the two parts occupying the position shown in FIG.
2c (prior to insertion of the rod 20 as described below) can pivot
freely about an axis that coincides essentially with the axis of
the hole T, as represented by arrows F in FIG. 3.
[0032] It will also be observed that in this position, the bores 12
of the two parts 10 are in general alignment. As a result, a rod 20
constituting a rod of a system for osteosynthesis of the spine can
be inserted into both bores, as shown in FIG. 2c.
[0033] Once the rod has been inserted, the parts 10, 10 are
prevented from tilting in the opposite direction by said rod 20, so
the device is locked in the wall of the occipital bone.
[0034] In addition, if it is desired to obtain firm locking between
the rod 20 and the two parts 10, 10, it is possible to fit each of
the parts 10 with any appropriate clamping means for this
purpose.
[0035] In the embodiment shown, the clamping means comprise a
tapped orifice 14 formed in the body 11 of each part 10 between the
outside wall of said body and the bore 12.
[0036] A clamping screw (not shown but conventional), e.g. fitted
with a hollow hexagonal socket for tightening purposes, can be
screwed into the orifice 14 after the rod 20 has been inserted and
once it occupies the desired position, thereby exerting pressure on
said rod so as to lock it in the corresponding housing.
[0037] Entirely reliable hooking is thus achieved by means of a
device that is extremely simple, being constituted by two identical
parts, and by forming a simple circular hole in the occipital case
by means of a trepan.
[0038] In addition, it will be understood from the above, that the
device can be put into place easily and quickly by a surgeon.
[0039] Naturally, the two parts 10, 10 and the clamping screws are
made of biocompatible alloy such as a titanium alloy or a stainless
steel alloy.
[0040] Naturally, the present invention is not limited in any way
to the embodiment described and shown, and the person skilled in
the art will know how to apply any variant or modification thereof
within the spirit of the invention.
[0041] In particular, although the description above relates to the
rod 20 being received in through bores formed in the bodies of the
parts 10, the invention also applies to the case where the rod is
fixed to each part by other means, and in particular when it is
placed in an open channel and is locked therein by an element that
closes the channel, in particular a screw element.
[0042] Although the invention herein has been described with
reference to particular embodiments, it is to be understood that
these embodiments are merely illustrative of the principles and
applications of the present invention. It is therefore to be
understood that numerous modifications may be made to the
illustrative embodiments and that other arrangements may be devised
without departing from the spirit and scope of the present
invention as defined by the appended claims.
* * * * *