U.S. patent application number 10/530683 was filed with the patent office on 2006-06-01 for self-locking osteosynthesis device.
This patent application is currently assigned to Biotech International (SARL). Invention is credited to Frederic Impellizzeri.
Application Number | 20060116678 10/530683 |
Document ID | / |
Family ID | 32039568 |
Filed Date | 2006-06-01 |
United States Patent
Application |
20060116678 |
Kind Code |
A1 |
Impellizzeri; Frederic |
June 1, 2006 |
Self-locking osteosynthesis device
Abstract
The self-locking osteosynthesis device includes a plate equipped
with holes for the passage of fixation screws. The invention is
characterised in that, at least in the areas defining the screw
holes, the aforementioned plate is made from a material having
mechanical properties such that the periphery of the holes can be
self-tapped by means of tapping screws which can be used to fix the
plate.
Inventors: |
Impellizzeri; Frederic;
(Salon de Provence, FR) |
Correspondence
Address: |
EGBERT LAW OFFICES
412 MAIN STREET, 7TH FLOOR
HOUSTON
TX
77002
US
|
Assignee: |
Biotech International
(SARL)
305, Allee de Crapone
F-13300 Salon De Provence
FR
|
Family ID: |
32039568 |
Appl. No.: |
10/530683 |
Filed: |
October 8, 2003 |
PCT Filed: |
October 8, 2003 |
PCT NO: |
PCT/FR03/02968 |
371 Date: |
September 2, 2005 |
Current U.S.
Class: |
606/291 ;
606/298; 606/910 |
Current CPC
Class: |
A61B 17/8057 20130101;
A61B 17/8605 20130101; A61B 17/864 20130101; A61B 17/8085
20130101 |
Class at
Publication: |
606/069 |
International
Class: |
A61F 2/30 20060101
A61F002/30 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 9, 2002 |
FR |
0212534 |
Claims
1. Self-locking osteosynthesis device comprising: a plate with
holes for passage of fixation screws, said plate being comprised of
a composite plate that contains holes having peripheries comprised
of inserts comprised of a plastic biocompatible material having
mechanical properties allowing a self-locking of the periphery of
the holes by tapping screws used for fixation of the plate, the
inserts being inserted into the holes provided in a remaining part
of the plate comprised of metal.
2. Device according to claim 1, wherein the peripheries of the
holes are comprised of inserts comprised of a high-performance
thermoplastic polymer.
3. Device according to claim 2, wherein the peripheries of the
holes are comprised of inserts comprised of polyether ether ketone
(PEEK).
4. Device according to claim 1, wherein the passage holes of the
fixation screws have a conical shape.
5. Device according to claim 1, wherein the remaining part of the
plate or base plate is comprised of titanium.
6. Device according to claim 1, wherein the inserts comprising the
periphery of the holes are integrated in the remaining part of the
plate or base plate by molding from a casting.
7. Device according to claim 1, wherein the inserts comprising the
periphery of the holes are integrated in the remaining part of the
plate or base plate by a mechanical assembly.
8. Device according to claim 1, further comprising: tapping screws
being comprised of a proximal part or head equipped with a conical
threading tapping mechanism having a diameter that increases in the
direction of the proximal end of the screws.
9. Device according to claim 1, further comprising: a mechanism
that prevents the rotation of the inserts engaged in the holes of
the plate.
Description
RELATED U.S. APPLICATIONS
[0001] Not applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not applicable.
REFERENCE TO MICROFICHE APPENDIX
[0003] Not applicable.
FIELD OF THE INVENTION
[0004] The invention relates to a self-locking osteosynthesis or
osteotomy device of the type comprising a plate having an
appropriate shape designed to be affixed on bone fragments using a
screw to ensure their coaptation.
BACKGROUND OF THE INVENTION
[0005] The coaptation of the bone fragments using plates of
titanium or another material and screws in order to create an
osteosynthesis is a common operation in bone surgery, for example,
orthopedic surgery.
[0006] In order to obtain a good result, it is necessary that the
plates or implants are screwed together permanently to the bone
fragments assembled from the implants. It is thus a requirement
that the screws can not unscrew and move back, to prevent any
displacement of the implants relative to the bone fragments.
[0007] On the other hand, it would often be desirable to be able to
choose the orientation of the screws relative to the plates and as
a function of the positioning and the shape of the fragments to be
assembled, which can improve the quality of the assembly.
[0008] In order to prevent the screws from unscrewing and moving
back, it has been proposed (EP-0,345,133, FR-2,794,963) to house
the locking instruments at the input of the screw holes into the
plates, in order to eliminate any possibility of axial movement of
the screws, after they are tightened in the bony material. For
example, it is provided in the document EP-0,345,133, to use check
screws that are outside-threaded and work together with a
complementary threading arranged at the input of the holes of the
screws that equip the plates, in a manner so that the head of the
screws is wedged against a check screw and that the check screws
can not move axially relative to the plates, this locking thus
ensuring the permanent support of the plate on the bone
fragments.
[0009] The devices proposed by several manufacturers represent at
this time the solutions that are most certain in terms of locking.
However, these relatively complex devices require the use of plates
having a relatively sizeable thickness that is totally incompatible
with a usage for operations on the bones of the hand or foot, for
which the thickness of the plates must be as reduced as possible,
taking into account the small size of the bones involved.
[0010] In the document EP-0.345.133, a device is again shown for
connecting two elements such as an implant and a bone, according to
which the implant comprises screw holes with axes oriented at an
angle to each other, in a manner so that the screws going through
these holes have orientations that are rigorously imposed by the
direction of these axes. A device of this type can only be planned
for the reduction of identical fractures, because otherwise it
would be necessary to provide as many plate models as possible
cases of fractures, which is practically impossible; in fact, it
does not offer any possibility to choose the orientation of the
screws as a function of the problems encountered in orthopedic
surgery.
[0011] In the document WO-00/66012, a plate is described for
osteosynthesis that can be locked, according to which the screws
and the screw holes provided in the plate are equipped,
respectively, with a locking threading and a sensible meshing
profile allowing the introduction of the screws into the plate in
an angled manner. The practical creation of a device of this type
would be difficult and it seems its effectiveness has not been
established.
[0012] In a general manner, in the field of osteosynthesis of small
bones requiring the use of plates having small dimensions, the
devices that are currently available on the market do not make
possible an angular clearance between the screws and the plate, so
that the screws thus have to be positioned perpendicularly to the
plate. However, in certain cases, it would be desirable to be able
to have one or more screws at an angle in order to use one or more
of the better quality bones for tightening the screws.
BRIEF SUMMARY OF THE INVENTION
[0013] The invention has the purpose of correcting the shortcomings
mentioned above for osteosynthetic systems using plates and screws,
notably because of the fact that the existing devices for serious
orthopedics (treatment of serious traumatisms) can not be
transposed to hand and foot surgery in which the dimension of the
plates that can be used becomes considerably reduced.
[0014] According to the invention, this purpose is achieved using
an osteosynthesis comprising a plate which is equipped with holes
for the passage of screws for fixation of this plate onto a bone
support. This device is notable in that the osteosynthesis plate is
made, at least in the zones that define the screw holes, of a
material that has mechanical properties to allow self-tapping of
the periphery of the holes with the tapping screws used to fix the
plate.
[0015] According to another characteristic arrangement, the
osteosynthesis plate is made of a composite plate with hole
peripheries comprised of inserts made of a plastic biocompatible
material, and inserted into the holes in the remaining part of the
plate which is made of metal.
[0016] According to another characteristic arrangement, the hole
peripheries are comprised of inserts made of polyether ether ketone
(PEEK), and the remaining part of the plate is made of
titanium.
[0017] According to another characteristic arrangement, the head of
the screws has a conical thread tapping mechanism.
[0018] By these characteristic arrangements above, the self-locking
head of the screws drills its own helicoid receiving groove in the
periphery of the holes in which they are engaged, in a manner so
that the screws are then automatically locked in the plate when
their head is tightened into its housing.
[0019] On the other hand, the osteosynthesis plate according to the
invention allows a selective angulation of the screws relative to
the axis of the holes of the plate, as a function of the
requirements.
[0020] In addition to obtaining the results mentioned above that
are very much of interest, the osteosynthesis device according to
the invention provides several advantages:
[0021] it has a simple design so that it can be made in an
economical manner;
[0022] it is easy to implement;
[0023] it is very reliable in its usage;
[0024] it can be used to ensure the locking of fixation screws of
osteosynthesis plates having small sizes, which is not allowed by
the systems currently proposed on the market.
[0025] This osteosynthesis device thus meets perfectly the
expectations of surgeons in terms of ease of implementation and
reliability of usage.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0026] The above purposes, characteristics, and advantages, and
still others, emerge better from the description that follows and
the attached drawings in which:
[0027] FIG. 1 is a perspective view, with a partial excerpt, of an
osteosynthesis plate according to the invention, with a
configuration given solely as an example.
[0028] FIG. 2 is a side view, with a partial section, of FIG.
1.
[0029] FIG. 3 is an elevation view, with a partial axial section
and enlarged scale, of a conical screw head that can be used to
implement the invention.
[0030] FIG. 4 is a detail view showing, in an axial section, an
insert implanted into an osteosynthesis plate for reception of a
tapping screw.
[0031] FIG. 5 is a section and perspective view of this insert.
[0032] FIG. 6 is a view showing a tapping screw tightened into this
insert and into a bone fragment.
[0033] FIG. 7 is an elevation view, with partial sections, showing
the fixation of an osteosynthesis plate according to the invention
for coaptation of bone fragments, two of the fixation screws (right
and left) are shown completely tightened into the bone fragments
and into the plate, a third screw (in the center) being shown
during its implementation.
DETAILED DESCRIPTION OF THE INVENTION
[0034] Reference is made to the drawings in order to describe an
embodiment example that is of interest, though in no way
restrictive, of the self-locking osteosynthesis device according to
the invention.
[0035] This device comprises a plate 1 equipped with passage holes
2 and fixation screws 3.
[0036] According to the invention, the plate 1 is made, at least in
the defining zones of the passage holes 2 of the screws 3, of a
material 4 that has the mechanical properties that allow a
self-locking of the periphery of these holes using tapping screws
for the fixation of the plate on the bone material.
[0037] The plate 1 can have any shape designed for the cases to be
treated with reduction of fractures or restorative surgery; the
shape shown in FIG. 1 is thus only a possible example of the shape,
and the same applies for the placement of the holes 2 in the
plate.
[0038] In a preferred manner, the plate 1 is made up of a composite
plate whose peripheries 4 of the holes 2 are made of a plastic
biocompatible material, the remaining part or surface 5 of the
plate being made of metal.
[0039] The peripheries 4 of the holes 2 can be made of a
high-performance thermoplastic polymer. In a preferred and
advantageous manner, the peripheries 4 of the holes 2 are made of
polyether ether ketone (PEEK) that has very high mechanical
properties and can be machined, like a metal.
[0040] The remaining part or surface 5 of the plates 1 can be made
of stainless steel, and in a preferred and advantageous manner, it
is made of titanium.
[0041] The solid fixation of the inserts made from the peripheries
4 of the holes 2 in the holes 6 arranged in the plate having a
metal base 5 can be made by a technique of molding from a casting
having the advantage of ensuring an intimate contact between the
two materials.
[0042] However, in a preferred manner, the implementation of the
inserts with PEEK 4 into the holes 6 of the metal plate 5 is done
by means of a mechanical assembly. The inserts made of PEEK 4 are
engaged, by deformation and pressure in the holes of the metal
plate and are then held in these holes. For example, the inserts 4
can comprise a peripheral groove 4a in which an upper edge 6a of
the holes 6 of the plate 1 come to engage, while the inserts are
pushed into the holes. When the screws 3 are screwed in, the
inserts 4 deform and are compressed between the edges of the holes
6 of the metal plate 5, which contributes to the solidity of the
anchorage of these inserts in the metal plate.
[0043] A mechanism is provided to prevent any possibility of
rotation of the inserts 4 in the holes 6 of the plate 5 when the
screws are screwed into these inserts. This mechanism can, for
example, be comprised of one or more grooves arranged in the inside
cylindrical surface of the holes 6 of the plate 5, in parallel to
the axis of the holes.
[0044] Using the mechanisms described above, the inserts 4 are
solidly connected to the plate 1 without the possibility of axial
movement or rotation.
[0045] The holes 2 have a conical shape. The large opening 2a of
the holes 2 accessible from the outside of the plate 1 comprise the
input for them, while the small opening 2b of the holes 2 opens
onto the inside of the plate designed to be applied to the parts of
the bone to be assembled. The conical wall 7 of the holes 2 of the
inserts 4 is smooth and does not contain any threading before the
use of the osteosynthesis plate.
[0046] The screws 3 that can be used for fixation of the
osteosynthesis plate 1 described above comprise a proximal part or
head 8 equipped with a conical threading tapping mechanism 9 having
a diameter that increases in the direction of the proximal end of
the screws.
[0047] These screws are, for example, the type described in the
document WO 98/40024. They comprise a distal part 10 provided with
a cylindrical threading 11, a proximal part or head 8 equipped with
a conical threading tapping mechanism 9, and, preferably, a smooth
intermediate section 12 arranged between the distal part 10 and
proximal part 8.
[0048] The screws are made of any suitable biocompatible material
and they can be advantageously of the "cannular" type, i.e.
equipped with an axial canal 13 that extends from one end to the
other of the screws, for the passage of a pin.
[0049] The nominal diameter of the cylindrical threading 111 of the
distal part 10 of the screws is less than the diameter of the small
opening 2b of the holes 2, so that the distal part of the screws
can go through the holes freely during the fixation of the
osteosynthesis plate 1 on the bones.
[0050] The composite osteosynthesis plate according to the
invention allows a tightening of the screws 3 at a certain
angulation relative to the axes of the holes 2 of the plate.
[0051] FIG. 7 shows an example of coaptation of the pieces of the
bones O1 and O2 by means of the osteosynthesis device according to
the invention.
[0052] On the right and left parts of the drawing, the
osteosynthesis plate 1 is seen pressed against the bone pieces O1
and O2, by means of two screws 3 completely tightened, whose distal
part 10 is tightened into the bone material 14 and whose proximal
part 8 is tightened into the inserts 4 of the plate, the screws
having different orientations and being locked using the devices
described above.
[0053] On the central part of the drawing, a screw 3 is shown in
the process of being tightened.
[0054] As indicated above, the invention makes it possible to
obtain a locking of the screws eliminating any possibility of
moving back after they are tightened in the bone material. This
locking is all the more effective since the conical threaded head
tapping mechanism of the screws produces a jamming effect resulting
from the conical assembly of the screws and the inserts.
* * * * *