U.S. patent application number 12/515787 was filed with the patent office on 2010-01-28 for prosthesis holder and application thereof.
This patent application is currently assigned to SPINEART SA. Invention is credited to Christophe Fuhrer, Jerome Levieux.
Application Number | 20100023019 12/515787 |
Document ID | / |
Family ID | 38197821 |
Filed Date | 2010-01-28 |
United States Patent
Application |
20100023019 |
Kind Code |
A1 |
Fuhrer; Christophe ; et
al. |
January 28, 2010 |
PROSTHESIS HOLDER AND APPLICATION THEREOF
Abstract
Prosthesis holder (1) made of a radiolucent material for a disc
prosthesis (2) constituted by at least two parts which are mobile
in relation to each another, including, on one side an element (9)
for coupling to a sleeve and on the other side, an element for
reversible coupling to a disc prosthesis, the reversible coupling
element is arranged in order to allow decoupling, by simple
traction exerted perpendicularly to a spinal column when the disc
prosthesis has been correctly impacted between two vertebrae and
the retention force of the reversible coupling element on the disc
prosthesis is adjusted so as not to allow decoupling by simple
traction when the disc prosthesis has not been correctly impacted,
and an assembly including a prosthesis holder and a disc
prosthesis.
Inventors: |
Fuhrer; Christophe;
(Valliere, FR) ; Levieux; Jerome; (Versoix,
CH) |
Correspondence
Address: |
YOUNG & THOMPSON
209 Madison Street, Suite 500
Alexandria
VA
22314
US
|
Assignee: |
SPINEART SA
Meyrin, Geneve
CH
|
Family ID: |
38197821 |
Appl. No.: |
12/515787 |
Filed: |
November 21, 2007 |
PCT Filed: |
November 21, 2007 |
PCT NO: |
PCT/FR2007/052374 |
371 Date: |
May 21, 2009 |
Current U.S.
Class: |
606/99 |
Current CPC
Class: |
A61F 2/4611 20130101;
A61F 2220/0025 20130101; A61F 2/442 20130101; A61F 2002/30904
20130101; A61F 2002/30649 20130101; A61F 2/0095 20130101; A61F
2002/3082 20130101; A61F 2002/305 20130101; A61F 2/4425 20130101;
A61F 2230/0013 20130101; A61F 2/4603 20130101; A61F 2002/30131
20130101; A61F 2002/30841 20130101 |
Class at
Publication: |
606/99 |
International
Class: |
A61B 17/58 20060101
A61B017/58 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 28, 2006 |
FR |
06 10416 |
Claims
1-10. (canceled)
11. A prosthesis holder (1) for a disc prosthesis (2) constituted
by at least two parts which are mobile in relation to each other,
said prosthesis holder being made of radiolucent material, and
comprising, on one side an element (9) for coupling to a sleeve and
on the other side, an element for reversible coupling to a disc
prosthesis, wherein the reversible coupling element is arranged in
order to allow decoupling by simple traction exerted
perpendicularly to a spinal column when the disc prosthesis is
stable between two vertebrae, wherein the retention force of the
reversible coupling element on the disc prosthesis is adjusted so
as not to allow decoupling by simple traction when the disc
prosthesis is not stable in the intervertebral space, and which is
arranged so as to firmly couple the mobile parts of the disc
prosthesis.
12. The prosthesis holder according to claim 11, wherein the
arrangement for firmly coupling the mobile parts of the disc
prosthesis comprise grooves or ribs (7, 21).
13. The prosthesis holder according to claim 11, further comprising
a follower device (8) of a cam (21) provided on the prosthesis,
said follower device (8) being elastically mounted on the
prosthesis holder.
14. The prosthesis holder according to claim 13, wherein the
follower device (8) is a bulge provided on U-shaped arms (3, 4) of
the prosthesis holder, said arms (3, 4) being arranged in order to
grip a disc prosthesis (2) and said bulge (8) being directed
towards the inside of the U.
15. The prosthesis holder according to claim 11, further comprising
a separate sleeve and retaining part (1) as well as a system for
the reversible coupling of the sleeve to the retaining part
(1).
16. The prosthesis holder according to claim 11, which is made of
thermoplastic resin.
17. An assembly comprising a prosthesis holder as defined in claim
11 and a disc prosthesis (2).
18. The assembly according to claim 17, said assembly being
pre-mounted.
19. The assembly according to claim 17, wherein the arrangement for
firmly coupling the mobile parts of the disc prosthesis comprise
grooves or ribs (7, 21).
20. The assembly according to claim 17, wherein the prosthesis
holder (1) further comprises a follower device (8) of a cam (21)
provided on the prosthesis, said follower device (8) being
elastically mounted on the prosthesis holder.
21. The assembly according to claim 20, wherein the follower device
(8) is a bulge provided on U-shaped arms (3, 4) of the prosthesis
holder, said arms (3, 4) being arranged in order to grip a disc
prosthesis (2) and said bulge (8) being directed towards the inside
of the U.
22. The assembly according to claim 17, wherein the prosthesis
holder further comprises a separate sleeve and retaining part (1)
as well as a system for the reversible coupling of the sleeve to
the retaining part (1).
Description
[0001] The present invention relates to prosthesis holders for
discs and applications thereof.
[0002] Pathologies of the spinal column are increasingly treated by
so-called "non-fusion" techniques and in particular by the
implantation of disc prostheses.
[0003] These prostheses appear to produce good results.
[0004] However, their implantation is a serious and sometimes
difficult operation. In fact, the ease and precision of the
implantation play a predominant role in the final result, almost as
much as the qualities of the disc prostheses themselves.
[0005] In fact, the position of the prosthesis in the disc space
must be perfect in order to guarantee correct functioning. The
surgeon verifies the position of the prosthesis during the surgical
intervention using X-rays.
[0006] A disc prosthesis is a small object which is difficult to
handle (of the order of one cm for its largest dimension and a few
mm for its thickness). As a result its fitting utilizes a separate
instrument called a prosthesis holder or insertion tool. This
instrument provided with a sleeve or handle is firmly fixed to the
prosthesis in order to allow the surgeon to handle the latter with
force. After fitting of the prosthesis, it must be able to be
withdrawn and the prosthesis left in place.
[0007] At present, these instruments are often complicated. In
particular, the mounting of the prosthesis on the prosthesis holder
can prove difficult. Furthermore, these prosthesis holders are made
of radio-opaque materials, which does not facilitate the X-ray
visualization of the position of the prosthesis.
[0008] Certain prosthesis holders such as Cervidisc prosthesis from
Scient'X or the Prestige prosthesis from Medtronics, form a clamp
which will grip the prosthesis. When the prosthesis is installed in
the correct position, it is released by loosing it from the clamp
or pulling on the sleeve.
[0009] These instruments work well, However, the mounting of the
prosthesis on its prosthesis holder is difficult and must be
carried during the intervention by the surgeon or competent nursing
staff. This represents a loss of time and risks of failure.
Furthermore these instruments are radio-opaque, generally they are
metallic. When the prosthesis is in place, the surgeon checks its
position (often in profile) to see whether it is suitable or
whether it must still be moved (for example impacted more). This is
done by X-rays. It is therefore very difficult for the surgeon to
distinguish between the prosthesis and the prosthesis holder; in
particular, the surgeon has difficulty in visualizing the position
of the front face of the prosthesis which is in contact with the
prosthesis holder.
[0010] Moreover, whatever the existing systems (Maverick prostheses
from Medtronics, Mobi-c from LDR, Prodisc from Synthes), the
disconnection of the prosthesis holder from the prosthesis does not
guarantee the stability of the implant in the disc space. In fact,
the surgeon loosens the prosthesis holder then withdraws it.
Therefore, when it is loosened it can easily be freed even if the
prosthesis is not very stable in the space.
[0011] Furthermore, the disc prostheses being constituted by at
least two parts which are mobile in relation to each other, it is
not easy to fit these prostheses onto their prosthesis holder
during the intervention in the operating suite (This is the case in
particular for the Prodisc (Synthes), or Prestige (Medtronics), or
Cervidisc prostheses (Scient'X).
[0012] The purpose of the invention is to remedy the drawbacks of
the above prosthesis holder by proposing a prosthesis holder made
of radiolucent material intended to be fixed on the one hand to the
prosthesis by a clamp system and having a reversible coupling
element with a sleeve such as a threaded or other hole on the other
side.
[0013] After lengthy research the Applicant has developed a
prosthesis holder which in particular does not interfere with the
locating of the prosthesis, is easy to withdraw, and can also make
it possible to verify the stability of the prosthesis. Furthermore,
the coupling to the prosthesis which is carried out in the
operating suite is very easy (simple screwing for example).
[0014] This is why a subject of the present application is a
prosthesis holder for a disc prosthesis characterized in that it is
made of radiolucent material, in that it comprises, on one side an
element for coupling to a sleeve and on the other side, an element
for reversible coupling to a disc prosthesis, in that the
reversible coupling element is arranged in order to allow
decoupling by simple traction exerted perpendicularly to a spinal
column when the disc prosthesis is stable between two vertebrae and
in that the retention force of the reversible coupling element on
the disc prosthesis is adjusted so as not to allow decoupling by
simple traction when the disc prosthesis is not stable between the
two vertebrae.
[0015] Thus, when the disc prosthesis has been correctly impacted
between two vertebrae and stability is correct, the decoupling
occurs by simple traction. If on the other hand the disc prosthesis
has not been correctly impacted or if the size of the prosthesis is
chosen incorrectly (too small) the prosthesis is not stable, in
this case, during the traction exerted by the surgeon, withdrawal
of the disc prosthesis occurs and the surgeon understands that the
disc prosthesis has not been correctly impacted or that its size is
not suited to the disc space in question.
[0016] In the present application and in the remainder of the text,
the term "reversible coupling" denotes a coupling which can be
followed by a decoupling, in particular without using a tool.
[0017] The element for reversible coupling of the prosthesis holder
to a disc prosthesis can take numerous forms. Preferably it
comprises a follower device of a cam provided on the prosthesis,
said follower device being elastically mounted on the prosthesis
holder.
[0018] For example, the follower device is a bulge provided on
U-shaped arms of the prosthesis holder (forming a fork), said arms
being arranged in order to grip a prosthesis and said bulge being
directed towards the inside of the U. Preferably the bulge is
provided towards the end of the U-shaped arms.
[0019] During the coupling, the follower device is guided for
example by a groove or rib constituting the start of the cam then
this groove or rib becomes hollow and the follower device (the
bulge) will be housed in the recess formed in order to hold the
prosthesis firmly.
[0020] Preferably a follower device is provided on each arm, in
particular in a symmetrical position with respect to the direction
of withdrawal. Advantageously, four follower devices are
provided.
[0021] In the example above, the depth of the cam hollow, the
length, the thickness of the arms carrying the follower device as
well as their geometry (profile in cross section in particular),
and the material constituting the prosthesis holder determine the
retention force of the reversible coupling element on the disc
prosthesis. A person skilled in the art can, with a few simple
experiments, determine the parameters necessary in order to obtain
the desired retention force.
[0022] For a prosthesis intended for the cervical region, the
retention force, necessary for disengagement, can be from 6 to 30
Newtons, preferably from 8 to 25 N, in particular from 9 to 20 N,
quite particularly from 10 to 15 N.
[0023] For a prosthesis intended for the lumbar region, the
retention force, necessary for disengagement, can be from 8 to 50
Newtons, preferably from 10 to 40 N, in particular from 12 to 30 N,
quite particularly from 15 to 25 N.
[0024] A person skilled in the art understands that the bulges can
be placed at various locations on the prosthesis holder as long as
they are elastically mounted and corresponding recesses are
provided on the prosthesis. Similarly, the bulges can be placed on
the prosthesis and the recesses on the prosthesis holder.
[0025] The element for reversible coupling of the prosthesis holder
to a disc prosthesis can also comprise studs, preferably
cylindrical in shape, intended to be fitted into corresponding
holes provided for this purpose in the prosthesis. The studs can be
scored and slightly open in order to be fitted with force and to
hold the prosthesis by adhesion, a minimum effort also being
necessary in order to achieve decoupling.
[0026] Lateral friction surfaces of a fork-shaped prosthesis holder
and of the prosthesis can also be practically parallel but slightly
trapezoidal (for example with a relative inclination at an angle of
0.5 to 1.degree., the shorter base being towards the opening of the
fork. A web can connect the branches of a fork-shaped prosthesis
holder and a bulge or a recess can be provided on the webbed
part.
[0027] A person skilled in the art can effortlessly understand when
the term "one" signifies "at least one". For example when it says
that the reversible coupling element of the prosthesis holder for a
disc prosthesis can comprise "a follower device" of a cam provided
on the prosthesis, "at least one follower device" is meant.
[0028] Under preferential conditions for implementation of the
invention, the above prosthesis holder comprises a separate sleeve
and retaining part as well as a system for the reversible coupling
of the sleeve to the retaining part.
[0029] The sleeve allows the surgeon to grasp the prosthesis
holder, for both insertion and impaction of the prosthesis and for
decoupling and verification of the correct insertion thereof.
[0030] The sleeve can be coupled to the retaining part by any means
well known to a person skilled in the art. There can be mentioned
for example screw-and-thread devices, bayonet, clip devices
etc.
[0031] Under preferential conditions for implementation of the
invention, the above prosthesis holder comprises two arms forming a
U-shaped clamp.
[0032] Each of the two arms preferably comprises a bulge, said
bulge being directed towards the inside of the U.
[0033] Under other preferential conditions for implementation of
the invention, the above prosthesis holder has as a maximum the
same width as the disc prosthesis for which it is intended.
[0034] Under yet other preferential conditions for implementation
of the invention, the above prosthesis holder has a length, in the
direction of the sleeve, preferably less than 10 cm, in particular
less than 5 cm, particularly less than 3 cm, quite particularly
less than 2 cm. For a prosthesis intended for the cervical region
it has a width preferably of 1 to 3 cm, in particular of 1.2 to 2
cm, particularly of 1.3 to 1.9 cm, quite particularly of
approximately 1.5 cm. For a prosthesis intended for the lumbar
region it has a width preferably of 2 to 6 cm, in particular of 3
to 5 cm, particularly of 3 to 4 cm, quite particularly of
approximately 3.5 cm.
[0035] Under yet other preferential conditions for implementation,
the prosthesis holder of the invention has as a maximum the same
height as the disc prosthesis for which it is intended. In
particular it has as a maximum the same height and as a maximum the
same width as the disc prosthesis for which it is intended.
[0036] The prosthesis holder of the invention is radiolucent. It is
for example made of thermoplastic resin. The thermoplastic resin is
for example high molecular weight polythene, PEEK loaded with glass
or carbon fibres or pure, polyphenyl sulphones marketed under the
name of Radel.RTM. and preferably acetal (thermoplastic homopolymer
acetal resin which is reinforced or not reinforced). It can also be
made of two or more two different materials. In this case, at least
the major part serving to grasp the prosthesis and in contact with
said prosthesis is advantageously radiolucent in order to make it
possible to visualize the prosthesis in the disc space, whilst the
remainder of the prosthesis holder is or is not made of radiolucent
material.
[0037] The sleeve can be made of the same materials as the
prosthesis holder, or of a different material, for example a metal
such as stainless steel which is perfectly suitable.
[0038] The prosthesis holder which is the subject of the present
invention possesses very useful qualities.
[0039] The fork being radiolucent, it is easy to visualize the
prosthesis in the disc space. Furthermore, given its design, simple
traction is sufficient to detach it from the prosthesis. This also
has the advantage of verifying the stability of the prosthesis, in
fact during traction, if the prosthesis remains connected to the
prosthesis holder, it can be considered that its primary stability
in the disc space was insufficient and another, larger size must
generally be chosen.
[0040] They make it possible to hold together the different parts
of a disc prosthesis during the intervention. They also have a
reduced space requirement since their height can be less than that
of the disc prosthesis and, similarly, their width can be less than
that of said disc prosthesis.
[0041] It is also possible to have a prosthesis already fitted to
the prosthesis holder in the factory. The mounting of the
prosthesis holder thus comes down to screwing a rod into the
threaded hole provided for this purpose. This operation is
obviously straightforward.
[0042] A subject of the present application is therefore also an
assembly (or kit) comprising a prosthesis holder and a prosthesis,
preferably pre-mounted as well as, in particular, a sleeve.
Preferentially, the various elements of the assembly are sterile
and particularly sterile during packaging. The sleeve may not be
sterile.
[0043] The arrangement in two parts of the prosthesis holder
additionally makes it possible to avoid handling the implant which
poses a risk of contamination. As the prosthesis is mounted on its
prosthesis holder in the factory, it is even possible to mount the
sleeve on the prosthesis holder without ever touching the
prosthesis, this is the so-called "no touch"technique, i.e. nothing
is touched, which is safest as regards asepsis.
[0044] These properties and qualities are illustrated hereafter in
the figures. They justify the use of the prosthesis holders
described above, in the fitting of disc prostheses between two
vertebrae.
[0045] A subject of the present application is therefore also a
method for fitting a disc prosthesis between two vertebrae in which
a disc prosthesis is placed between two vertebrae using a
prosthesis holder described above.
[0046] A subject of the present application is also method for
choosing a disc prosthesis to be inserted between two vertebrae, in
which a disc prosthesis is placed between two vertebrae using a
prosthesis holder described above, traction is exerted on the
prosthesis holder and it is observed whether the disc prosthesis
remains in place or comes out with the prosthesis holder.
[0047] The preferential conditions for utilization of the
prosthesis holders described above also apply to the other subjects
of the invention referred to above, in particular to the assemblies
comprising an above prosthesis holder and a disc prosthesis.
[0048] The invention will be better understood by referring to the
attached drawings in which
[0049] FIG. 1 shows a perspective view of a disc prosthesis
constituted by at least two parts which are mobile in relation to
each other, with its parts moved apart from each other.
[0050] FIG. 2 shows a perspective view of a disc prosthesis holder
as well as the corresponding prosthesis, separated,
[0051] FIG. 3 shows a perspective view of a disc prosthesis holder
as well as the corresponding prosthesis, pre-mounted.
[0052] FIG. 1 shows a disc prosthesis constituted by at least two
parts which are mobile in relation to each other, with its pieces
moved apart from each other.
[0053] The prosthesis 2 comprises an upper plate and a lower plate,
approximately square in shape with rounded corners viewed from
above. Each plate of the prosthesis 1 has a size of approximately
1.5 cm by 1.3 cm in this representation. The lower plate comprises
a recess in which a dome 25 is housed. The upper plate comprises a
concave recess the shape of which corresponds to that of the
dome.
[0054] The prosthesis 2 comprises hollowed out elements
complementary to raised elements of the corresponding prosthesis
holder of FIG. 2. Each plate comprises in particular along two
opposite sides, ribs 21 formant a cam. Recesses 23, four in number,
two on the left and two on the right of the prosthesis i.e. two per
plate, are intended to receive the bulges 8 of the prosthesis
holder. The dimensions of these elements are suited to those of the
corresponding elements of the prosthesis holder.
[0055] The prosthesis 2 comprises, above and below, pointed
elements 24 which allow the anchoring of the prosthesis after
impaction.
[0056] FIG. 2 shows a disc prosthesis holder 1 as well as the
corresponding prosthesis 2, separated. The prosthesis holder 1 is
shown here without its sleeve. It has a general U-shaped fork
appearance comprising two branches 3, 4 and a central part 5. Each
of the branches comprises three ribs, a central rib 6, two
secondary ribs 7 (only one per branch is visible in the figure).
The central rib 6 with a significant thickness (from 1 to 5 mm
according to the size of the prosthesis and its intended cervical
or lumber region) serves as a main guide and gives solidity to the
assembly, but does not allow the reversible coupling according to
the invention. This is conferred by the secondary ribs 7 (with a
thickness of approximately 0.4 to 3 mm) which comprise at their end
a bulge 8 projecting towards the inside of the fork. This bulge 8
serves as a follower device. The bulges 8 are elastically mounted
thanks to the geometry (profile in cross section in particular),
and with the material constituting the prosthesis holder 1 here
made of acetal, allowing the two arms to be moved apart from each
other.
[0057] The cooperation of the ribs of the prosthesis holder 1 and
the prosthesis 2 prevent the moving apart of the parts of the
prosthesis 2 and the cooperation of the bulges 8 and recesses 23,
combined with the cooperation of the dome 25 with the concavity of
the upper part of the prosthesis 2, avoids the pieces of the
prosthesis 2 sliding on one another, in order to firmly couple the
two parts of the prosthesis 2.
[0058] In its central part 5, the prosthesis holder 2 comprises a
threaded hole 9 into which a sleeve (not shown) can be screwed.
[0059] A web 10 connects the two arms 3 and 4 for good
rigidity.
[0060] The prosthesis holder 1 has a height slightly less than that
of the disc prosthesis 2. It has a length, in the direction of the
sleeve, of approximately 1.5 cm, a width of approximately 1.5 cm
and a height of approximately 6 mm in this representation.
[0061] The prosthesis 2 is here shown with the two plates moved
together, the dome 25 in contact with the concave recess in the
upper plate.
[0062] The prosthesis 2 comprises hollowed-out elements
complementary to raised elements of the prosthesis holder and
comprises in particular ribs 21 forming a cam which follows the
bulge 8 during the coupling. The web 10 is housed in the space 22
between the upper plate of the prosthesis and the lower plate.
Recesses 23, four in number, two on the left and two on the right
of the prosthesis are intended to receive the bulges 8 of the
prosthesis holder. The dimensions of these elements are suited to
those of the corresponding elements of the prosthesis holder.
[0063] The prosthesis 2 comprises, above and below, pointed
elements 24 which allow the anchoring of the prosthesis after
impaction.
[0064] During the coupling, shown in FIG. 3, the secondary ribs 7
are inserted into the ribs 21 serving as corresponding cams. In
abutment, the bulges 8 are engaged in the recesses 23 so as to
firmly couple the two parts of the prosthesis 2. A person skilled
in the art understands, on examining the figures, that the bulges 8
can be placed at various locations on the prosthesis holder so long
as they are elastically mounted and corresponding recesses 23 are
provided on the prosthesis. Similarly, the bulges 8 can be placed
on the prosthesis and the recesses 23 on the prosthesis holder.
[0065] The prosthesis 1 can be supplied with its prosthesis holder
2 already fitted in the factory as shown in FIG. 3. The final
mounting of the prosthesis holder is thus limited to screwing a
sleeve into the threaded hole 9 provided in its central part 5.
[0066] The depth of the hollow 23 of the ribs 21, the length, the
thickness of the arms 3, 4 carrying the follower device as well as
their geometry (profile in cross section in particular), and the
material constituting the prosthesis holder 1 determine the
retention force of the prosthesis holder on the prosthesis.
[0067] In order to withdraw the prosthesis holder 1 with a view to
leaving the prosthesis 2 in place, and to verify the satisfactory
stability of the latter, it is sufficient to pull on the sleeve in
the direction AB. If the bulges 8 become disengaged from the
recesses 23 leaving the prosthesis in place, this signifies that
the latter is satisfactorily stable. The parts of the prosthesis
are released and the plates can be moved in relation to each other,
according to the ball joint provided by the dome.
[0068] FIG. 3 also shows that the use of ribs (or elongated slots
for the female part) for coupling the two parts of the prosthesis 2
by means of the prosthesis holder 1 makes it possible to
appreciably reduce the space requirement of the assembly. The
prosthesis holder 1 in fact has the same width as the disc
prosthesis 2 as can be clearly observed in the figure. It also has
the same height as the disc prosthesis 2. A reduced space
requirement is particularly useful as regards surgery.
* * * * *