U.S. patent number 3,759,257 [Application Number 05/234,097] was granted by the patent office on 1973-09-18 for connector for fractured tubular bones.
This patent grant is currently assigned to SAID Fischer, by said Muller. Invention is credited to Artur Fischer, Jean-Nicolas Muller.
United States Patent |
3,759,257 |
Fischer , et al. |
September 18, 1973 |
CONNECTOR FOR FRACTURED TUBULAR BONES
Abstract
An elongated rod-shaped element can be inserted into the curved
longitudinal cavity of a fractured tubular bone. At its front end
it is provided with an expander portion by means of which it can
expand an expansion element provided at the front end of a tubular
sleeve which surrounds the rod, when the latter is moved axially
and rearwardly with respect to the front end of the tubular sleeve.
The expander portion may be releasably connected with the rod for
which purpose inter-engaging coupling portions may be provided on
the rod and on the expander portion.
Inventors: |
Fischer; Artur (Tumlingen,
DT), Muller; Jean-Nicolas (Strassburg,
FR) |
Assignee: |
SAID Fischer, by said Muller
(N/A)
|
Family
ID: |
5801443 |
Appl.
No.: |
05/234,097 |
Filed: |
March 13, 1972 |
Foreign Application Priority Data
|
|
|
|
|
Mar 13, 1971 [DT] |
|
|
P 21 12 138.0 |
|
Current U.S.
Class: |
606/63 |
Current CPC
Class: |
A61B
17/7225 (20130101); A61B 17/7266 (20130101) |
Current International
Class: |
A61B
17/68 (20060101); A61B 17/72 (20060101); A61f
005/04 () |
Field of
Search: |
;128/92BC,92BB,92R,92CA,92B,92D ;85/77,84 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Gaudet; Richard A.
Assistant Examiner: Yasko; J.
Claims
We claim:
1. A supporting device for fractured tubular bones having a
longitudinally extending interior cavity, comprising an elongated
rod-shaped element adapted to be inserted with clearance into the
cavity and having a trailing end portion and a leading end portion;
an expander element provided on said leading end portion; an
elongated supporting tube dimensioned to fit over said rod-shaped
element and adapted to be inserted into the cavity by sliding over
said rear end portion and onto said rod-shaped element; an
expansible element; cooperating coupling portions on said
expansible element and on the front end of said tube for releasably
connecting said expansible element to said tube so that said
expansible element abuts against said expander element when said
tube is slid over said rod-shaped element; and moving means for
moving said rod-shaped element in said tube axially of the same and
rearwardly away from said first end so as to draw said expander
element into and thereby expand said expansible element.
2. A device as defined in claim 2, wherein said coupling portions
are mating screw threads.
3. A device as defined in claim 1, said moving means comprising a
nut having internal screw threads; and further comprising an
extension rod having a diameter not exceeding that of said
rod-shaped element and connectable with said trailing end portion
of the latter, said extension rod and said trailing end portion
having external screw threads adapted to mesh with said internal
screw threads.
4. A device as defined in claim 1, wherein at least some of said
elements and means are of rust-free steel.
5. A supporting device for fractured tubular bones having a
longitudinally extending curved interior cavity, comprising an
elongated curved supporting tube element adapted for insertion into
said cavity longitudinally thereof and having a leading end
portion; an expansible element provided on said leading end
portion; an expander element for expanding said expansible element;
a rod-shaped element dimensioned to be receivable in said tube
element and having a front portion, a rear portion, and an
intermediate portion with at least the latter having a
cross-section dimensioned to permit angular displacement of said
rod-shaped element in said tube element; cooperating coupling
portions on said expander element and front portion for effecting
coupling of said expander element to said rod-shaped element in
response to angular displacement of the latter; and moving means
for moving said rod-shaped element in said tube rearwardly of said
leading end portion so as to effect expansion of said expansible
element with said expander element.
6. A device as defined in claim 5, said expander element having an
opening, and said coupling portions being transverse projections on
said front portion and engaging surfaces in the region of said
opening, said engaging surfaces being engageable with said
projections when said front portion is inserted into said opening
and said rod-shaped element is angularly displaced.
7. A device as defined in claim 6, wherein said projections are
diametrically opposite one another.
8. A device as defined in claim 7, said expander element being
provided in the region of said opening with a pair of diametrally
opposite recesses each bounded in part by one of said engaging
surfaces.
9. A device as defined in claim 8, said opening having one end into
which said front portion is insertable, and an other end bounded by
an endface extending transversely to the axis of said opening; and
wherein said recesses are provided in said endface.
Description
BACKGROUND OF THE INVENTION
The present invention relates generally to a medical appliance and
more particularly to a connector for fractured tubular bones.
Connectors for fractured bones are known, and it is known to use
connectors having expansible elements for anchoring in a hole which
is drilled into the bone fragments which are to be reunited. If,
however, tubular bones are fractured -- which have a longitudinally
extending curved interior cavity which is filled with bone marrow
-- it was until recently unknown to use that type of connector;
instead these bone fractures were always repaired by driving pins
into the fragments of the bone.
The state of the art was advanced in this respect with our proposal
in a co-pending application Ser. No. 227,371 filed in our names on
Feb. 18, 1972, under the title "Supporting Device for Fractured
Tubular Bones," wherein there is proposed a sleeve-shaped support
element into which a rod-shaped expander element is inserted. The
support element is curved in a manner which is at least
substantially the same as the curvature of the interior cavity of
the tubular bone, and when inserted into this cavity via an opening
drilled into the bone for this purpose in order to afford access to
the cavity, the support element is in contact with the wall surface
bounding the bone marrow cavity over a relatively large surface
area, due to its curvature corresponding to that of the cavity
itself. With this device the fragment of the bone are secured
against lateral displacement and cannot shift relative to one
another at the fracture line. Because of this, callus may be formed
in a very brief time at the fracture line, thus reuniting the bone
fragments.
The device in the aforementioned copending application can be
anchored by means of an expansible portion in the bone fragments,
permitting a much earlier application of loads to the bone than was
possible with the previous practice of driving pins into the bones.
Furthermore, the fact that the support element can be so anchored
serves, of course, to eliminate the need for the use of wires or
pins which might otherwise have to be driven into the bone from the
side in order to secure the support element against shifting or
twisting in the cavity, and the overall effect observed with the
construction set forth in the above-mentioned application is a
significant reduction in the hospitalization time of a patient
whose fracture has been repaired with the aforementioned
device.
However, it has also been observed that even this significantly
improved device does not meet all requirements as yet. The support
device according to the aforementioned application can be readily
inserted into the cavity of the tubular bone when the bone
fragments are either not or only slightly displaced relative to one
another in lateral direction at the fracture line. However, if such
displacement has occurred and is of a more than slight nature, then
the fact that the outer diameter of the sleeve-shaped support
element is adapted to the inside diameter of the bone marrow cavity
wouls result, when the device is driven into the cavity in contact
with the laterally displaced downstream bone fragment, that is the
fragment which the device would encounter only after it has been
driven into the first fragment, in desctruction of this downstream
bone fragment beyond the fracture line.
SUMMARY OF THE INVENTION
Accordingly, it is a general object of the present invention to
provide a device or connector of the type here under discussion
which is a further improvement over what is known from the
aforementioned application and which avoids the disadvantages just
outlined.
More particularly it is an object of the present invention to
provide an improved supporting device for fractured tubular bones
having a longitudinally extending interior cavity.
An additional object of the present invention is to provide such a
device which permits preliminary fixation of the bone fragments in
their correct relative position before the supporting sleeve of the
device is inserted into the bone marrow cavity, and which permits
holding them in this position until the supporting sleeve has been
so inserted.
In pursuance of these objects and of others which will become
apparent hereafter, one feature of the invention resides, briefly
stated, in a supporting device for fractured tubular bones having a
longitudinally extending interior cavity which device comprises an
elongated rod-shaped element adapted to be inserted with clearance
into the cavity and having a trailing end portion and a leading end
portion. An expander element is provided on the leading end portion
and an elongated supporting tube is provided, being dimensioned to
fit over the rod-shaped slement and adapted to be inserted into the
cavity by sliding over the rear end portion and onto the rod-shaped
element. An expansible element is provided at the front end of the
tube and is dimensioned to abut the expander element when the tube
is slid over the rod-shaped element. Moving means is also provided
for the purpose of moving the rod-shaped element in the tube
axially of the same and rearwardly away from the front end of the
tube whereby the expander element is drawn into and thereby expands
the expansible element.
Another concept according to the present invention proposes to
achieve the aforementioned objects by utilizing a supporting device
having an elongated curved supporting tube element adapted for
insertion into the cavity longitudinally thereof and having a
leading end portion. An expansible element is provided on the
leading end portion and an expander element is also provided for
expanding the expansible element. A rod-shaped element is
receivable in the tube element and has a front portion, a rear
portion and an intermediate portion of which at least the latter
has a cross-section so dimensioned as to permit angular
displacement of the rod-shaped element in the tube element.
Cooperating coupling portions are provided on the expander element
and the front portion of the rod-shaped element in order to effect
coupling of the expander element to the rod-shaped element in
response to angular displacement of the latter. Moving means is
again provided which moves the rod-shaped element in the tube
rearwardly of the leading end portion so as to effect expansion of
the expansion element with the expander element when the latter is
connected with the rod-shaped element.
When the device is constructed in accordance with the
first-mentioned concept of the invention, the rod-shaped element in
fact serves as a pin permitting the preliminary fixation of the
bone fragments relative to one another. The fractured tubular bone
is first provided with a hole in the region of its bulge, so as to
gain access to the bone marrow cavity. Through this hole, provided
in conventional manner with a drill or the like, is inserted the
rod-shaped element -- which is curved in conformance with the
curvature of the bone marrow cavity. The outside diameter of the
rod-shaped element, which is small with respect to the diameter of
the bone marrow cavity, makes it possible to insert the rod into
all of the bone fragments without any difficulty, even though a
relatively significant lateral displacement of the bone fragments
relative to one another at the fracture line may have occurred.
Once the rod-shaped element is so inserted into the bone marrow
cavity, the fragments are now aligned in longitudinal direction and
held in this position. Over the thus inserted rod the similarly
curved supporting tube is then pushed into the bone marrow cavity
untl the expansible element which is provided at the front end of
the tube, comes in contact with the expander element which is
provided at the front end of the rod-shaped element. The moving
means is now operated, consisting advantageously of a cap sleeve
which is internally threaded to mesh with external thread provided
at the rear end of the rod-shaped element, and when this is done
the rod-shaped element is drawn axially rearwardly into the tube so
that the expander element expands the expansible element on the
tube, anchoring the entire device in one of the bone fragments.
During the anchoring operation the rod-shaped element moves only in
axial direction of the tube, it being evident that the curvature of
the tube and of the rod-shaped element will prevent a turning or
twisting of the latter in the tube. Due to the curvature of the
tube, the latter is in contact with the inner wall bounding the
bone marrow cavity over a relatively large surface area, whereby an
excellent securing of the bone fragments against lateral
displacement is obtained. Of course, the anchoring of the device in
the bone fragment means that the other bone fragment in which the
device is not anchored may be engaged by the moving means or
another component provided for this purpose, thereby exerting an
axial stress upon the bone fragments in a sense drawing them
together to prevent their relative axial displacement.
It is advantageous, but not absolutely necessary to provide mating
screw threads on the rod-shaped element and on the expander
element, so that the latter can be releasably connected with the
rod-shaped element; the same expedient may be used for releasably
connecting the expansible element to the supporting tube.
As is well known in this field of art, components for devices of
the type under discussion are usually manufactured from V2A or V4A
steel, that is material which is not only expensive but can only be
shaped and worked with considerable difficulty due to its hardness.
Because the rod-shaped element can be made separately from the
expander element by resorting to the above-mentioned possibility of
releasably connecting them via screw threads, these elements can be
manufactured individually, avoiding the necessity for utilizing a
large-diameter rod and removing material from it in such a manner
as to obtain over most of its length a small diameter corresponding
to the desired diameter for the rod-shaped element, whereas a
remaining portion having the original larger diameter will
constitute the expander element. This is of course a possibility,
but due to the difficulty of working the type of steel here in
question, of which the components of the device according to the
present invention are advantageously made, the solution of being
able to make the rod-shaped element and the expander element
separately and connecting them to one another is currently
preferred because it is less expensive.
It is also proposed according to the present invention to provide
an extension rod which can be threaded into a tapped bore provided
in the rear endface of the rod-shaped element. The extension rod
should have a diameter corresponding to that of the rod-shaped
element itself, and it is advantageous if its threads provided on
its outer surface are also the same as those on the rear end of the
rod-shaped element and can mesh with the threads of the cap nut
which is effectively used for moving the rod-shaped element
relative to the tube. However, it is also possible to so construct
the extension rod that it can be threaded onto the threads of the
rear portion of the rod-shaped element if this is desired, and in
either case, the provision of such an extension permits the surgeon
the complete insertion of the at least the major portion of the
threaded rod-shaped element into the bone marrow cavity without
difficulty, whereupon the extension rod can then be removed if
desired or necessary.
Insofar as the second embodiment is concerned which was briefly
outlined above, it should be understood that here again the bone
fragments can be pre-aligned before the device is used to connect
them. In this case, however, a conventional pin which in the prior
art was used for connecting such bone fragments to one another, can
be inserted into the bone marrow cavity to fix the bone fragments
with reference to one another against relative displacement.
Thereafter the tube is pushed over the pin into the bone marrow
cavity, while the bone fragments are held by the pin against
relative displacement. The pin is now withdrawn and the rod-shaped
element is inserted into the tube. The rod-shaped element can be
given a small cross section so that it can contact the inner
surface of the curved tube over a relatively large surface area. At
least the intermediate portion of the rod-shaped element is of such
cross-section or diameter that the rod-shaped element has
sufficient flexibility or elasticity to permit it to be angularly
displaced in the curved tube to an extent sufficient to permit
engagement of the front portion of the rod-shaped element with the
expander element located at the front of the tube, in the region of
the expansible element.
However, if the rod-shaped element is constructed in this manner,
its torsional strength is not sufficient to permit proper
drawing-in of the expander element into the expansible element. On
the other hand, its tensile strength is fully sufficient for this
purpose and the invention therefore provides for use of a cap nut
or sleeve which is engageable with a rear threaded end portion of
the rod-shaped element and which, when turned in requisite sense,
will cause the rod-shaped element to perform a movement in the tube
which is purely axially of the tube, whereby the rod-shaped element
is subjected only to tensile forces in drawing the expander element
into the expansible element.
The rod-shaped element may be provided at its front end with
coupling portions capable of engagement with similar coupling
portions on the expander element, for instance oppositely located
projections which can be inserted through a corresponding aperture
in the expander element and are engageable with the latter after
the rod-shaped element performs a 90.degree. turn with reference to
the expander element. This construction is advantageous because it
requires angular displacement of the rod-shaped element only
through about 90.degree., whereas a threaded connection between the
rod-shaped element and the expander element would require at least
two or three complete turns of the rod-shaped element, which would
have to result in the engagement of at least two or three threads
on the rod-shaped element with threads on the expander element in
order to take up the necessary tensile force. Evidently, the
possibility outlined above is preferable under the circumstances,
although the use of threads is not to be excluded.
The novel features which are considered as characteristic for the
invention are set forth in particular in the appended claims. The
invention itself, however, both as to its construction and its
method of operation, together with additional objects and
advantages thereof, will be best understood from the following
description of specific embodiments when read in connection with
the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is an axial section through a tubular bone with a device
according to the present invention inserted into it;
FIG. 2 is a fragmentary axial section illustrating a component of
the device in FIG. 1;
FIG. 3 is a view similar to FIG. 1 illustrating a further
embodiment of the invention; and
FIG. 4 illustrates another concept of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Discussing the drawing in detail, and firstly referring to FIGS. 1
and 2 thereof, it will be seen that the device is generally
identified with reference numeral 1 and is advantageously produced
in all its components of V2A or V4A steel. It has an elongated
supporting tube or sleeve 2 to the front end of which is mounted an
expansible element 3 of known construction. In utilizing this
device the bone fragments 12 are first aligned by pushing the
threaded rod-shaped element 5 into the longitudinally extending
curved bone marrow cavity 18, thereby assuring that the bone
fragments 12 are aligned in longitudinal direction at the surface
of the fracture 13.
Once the rod-shaped element 5 has been so inserted, the tube 2 with
the expansion member 6 accomodated in the expansible element 3 and
provided with an axial passage, is slipped over the rod-shaped
element 5 and inserted into the bone marrow cavity 18 until the
element 6 contacts the enlargement 20 provided at the front end
portion of the element 5.
When, now, the element 5 is shifted in axially rearward direction
of the tube 2, for instance by means of an internally threaded cap
sleeve 4 which is threaded onto the rod-shaped element 5 at the
rear end thereof, and is guided in a widened portion 7 at the rear
end of the passage of the tube 2, the sleeve 4 will bear against a
shoulder 8 or else the rear end of the tube 2, so that upon its
rotation it will draw the element 5 rearwardly with the result that
the portion 20 will bear against the member 6, moving the same into
the element 3 and causing the latter to spread outwardly and become
anchored in the bone marrow cavity.
It is advantageous for the axial length of the member 4 to be so
calculated that when the rod-shaped element 5 has been withdrawn
rearwardly to the extent necessary to effect full expansion of the
element 3, its rear end will be sufficiently forwardly spaced from
the rear end of the member 4 to permit a cap screw 9 to be threaded
into this rear end, closing it. The cap screw 9 has a head 10
abutting against the annular disc 11.
Projections 14 are provided on the member 6 and guided in slots
which extend longitudinally of the element 3 to prevent relative
angular displacement of the member 6 and the element 3. The element
3, incidentally, can be threaded into an internal thread 17
provided at the front end of the sleeve 2 by means of an exterior
thread 16 provided on the element 3.
It will be seen in FIG. 2 that the rod 5 will be constructed from
several parts, namely a portion 21 carrying the portion 20 and
provided with an internal thread 22 into which another portion 23
may be threaded by means of an externally threaded part 24. At the
rear end the rod 5 may be extended by a further portion 25 which is
threadedly connected with it in the manner illustrated for the
purposes outlined earlier.
Coming to the embodiment illustrated in FIG. 3 it will be seen that
there we have shown a device wherein the tube 2 (it should be noted
that like reference numerals identify like elements as in FIGS. 1
and 2) can be pushed over a pin which is temporarily inserted into
the bone marrow cavity to provide for temporary and preliminary
fixation of the bone fragments 12. In this embodiment the member 6
is located in a recess at the forward end of the device, being
provided with an internal thread 30, the root diameter of which is
slightly larger than the outside diameter of the pin which is to be
used for the preliminary fixation of the bone fragments. Once the
pin has been inserted, the tube 2 is pushed over to the maximum
extent desired, and thereupon the pin (which is not shown) is
withdrawn. Now, the rod-shaped element 5 is inserted into the tube
2 and in this embodiment the element 5 is provided at least in its
intermediate portion of a cross-section so selected that it can be
angularly displaced within the tube 2, that is that it is
sufficiently flexible to permit such turning. This is necessary to
permit connection of the member 6 with the element 5. The element 5
may adapt itself to the curvature of the tube 2 during insertion
and during angular displacement due to the sufficient elasticity
resulting from its small cross-section at least at the intermediate
portion.
The intermediate portion is identified with reference numeral 32
and bounded by a threaded portion 33 to which a cap nut of sleeve
shaped configuration and identified with reference numeral 34 is to
be secured. At the forward end of the rod-shaped element 5 the
latter is provided with a threaded portion 31 which can be threaded
into the internal thread 30 of the member 6 as a result of the
angular displacement of the rod-shaped element 5 in the tube 2.
However, as shown in FIG. 4, it is also possible -- and believed
currently to be preferable -- to provide for a different way of
connecting the member 6 with the element 5. The forward end portion
of the element 5 is provided with projections, preferably two
opposite projections 40, constituting a lacking portion that may be
passed through a corresponding aperture 41 provided in member 6 for
this purpose. After such insertion the rod-shaped element 5 is
turned through approximately 90.degree., whereupon the projections
40 engage the member 6 as illustrated and when the rod-shaped
element 5 is then drawn axially through the tube 2, the member 6 is
taken along to expand the element 3.
Additional recesses are provided at forwardly directed front side
of the member 6, being offset through 90.degree. with respect to
the aperture 41, so that the projections 40 can engage in and
become locked in these recesses 42 to thereby assure that the
element 5 cannot twist with reference to the member 6, and vice
versa.
It will be understood that each of the elements described above, or
two or more together, may also find a useful application in other
types of constructions differing from the types described
above.
While the invention has been illustrated and described as embodied
in a connector for fractured tubular bones, it is not intended to
be limited to the details shown, since various modifications and
structural changes may be made without departing in any way from
the spirit of the present invention.
Without further analysis, the foregoing will so fully reveal the
gist of the present invention that others can, by applying current
knowledge readily adapt it for various applications without
omitting features that from the standpoint of prior art, fairly
constitute essential characteristics of the generic or specific
aspects of this invention and, therefore such adaptations should
and are intended to be comprehended within the meaning and range of
equivalence of the following claims.
What is claimed as new and desired to be protected by Letters
Patent is set forth in the appended claims.
* * * * *