NEW INTRA-LARYNGEAL ENDOPROSTHESIS
The present invention relates to the field of
prostheses intended to restore both swallowing,
5 breathing and speech in patients with a dysfunctional
larynx. More specifically, the present invention
relates to a flap valve device forming an
intralaryngeal prosthesis intended to be implanted
within an in-situ anatomical larynx the function of
10 which is to allow breathing while providing a seal
against elements such as saliva, mucus, or any other
element derived from the alimentary bolus. The complete
intralaryngeal prosthesis and its various applications
also form part of the subject matter of the present
15 invention.
There are various pathologies or consequences of
pathologies and/or of treatments which lead patients to
present dysfunctions of the larynx. Some of these
20 events lead to partial or total paralysis, which may be
either temporary or permanent. The larynx is an osteocartilagenous
duct the main role of which is of a
respiratory nature. Any dysfunctionality may therefore
compromise the breathing function in the patient. The
25 larynx plays an important role in the swallowing
process insofar as its closure protects the lower
airways. Any dysfunctionality therefore leads to
problems of undesirable elements, liquid or solid,
entering the lower airways.
30
The prior art has only very few solutions to offer to
remedy a dysfunctional larynx because the larynx has
many functions and requires complex prostheses the
placement of which involves a surgical procedure. It is
35 therefore necessary for the device to be suited to the
various functions of the larynx and also to have a
substantial life span under physiological conditions so
as to limit the operations that the surgeon has to
perform. Moreover, the device needs to be made from a
material that is biocompatible, strong, light, durable
and has to have a shape best suited to the site at
which it will be implanted, in order to cause the least
5 trouble to the patient.
Patent application EP 0815807 describes a prosthesis
intended to remedy a dysfunctional larynx, said
prosthesis consisting of a silicone tube which at one
10 of its ends shaped into a bevel has, on the one hand,
an inclined shut-off face and, on the other hand,
lateral orifices for communication between the inside
and the outside of the tube that forms the prosthesis.
In practice, the inclined shut-off face directs the
15 alimentary bolus from the mouth toward the esophagus,
whereas the lateral communication orifices allow air to
circulate in both directions. Nevertheless, it is true
that leaks may occur through those lateral orifices
and, more particularly, fluid or reflux of fluid or any
20 other element of the alimentary bolus may enter the
lover airways. This is because in practice, the
orientation of the shut-off face is not enough on its
own to ensure total sealing.
25 Patent application EP 08872036 also describes an
implant system intended to restore respiratory, speech
and swallowing functions in a patient with a
dysfunctional larynx. That application describes a flap
valve device made at least in part from a semi-rigid,
30 biocompatible lightweight and strong material, for
example silicone. The device described is preferably
made up of a silicone structure, silicone valve flaps
and a peripheral reinforcing ring made of titanium
which is embedded in the silicone of the structure. The
35 novelty of that device lies in a double-flaps system
the objective of which is to allow breathing and
swallowing while forming a perfectly fluidtight shutter
(obturator) thanks to a bevel cut at the circumferences
of the two circular valve flaps and at the
circumference of the internal surface of the annular
bearing structure. That device has a life that is
limited because of the deformation of the valve flaps
5 under physiological conditions and because mold appears
due to the presence of the silicone which is readily
colonized by undesirable cells. The device has
therefore to be replaced in the relatively short term.
10 These devices of the prior art have the major defect of
being sensitive to wear and to colonization under
physiological conditions, notably by mold.
Specifically, any deformation of the shutter inevitably
leads to a lack of sealing and therefore to poor
15 operation of the device that is supposed to remedy the
dysfunctionality of the larynx. It is therefore
necessary for a surgeon to operate to replace the
defective element or elements in the devices of the
prior art.
2 0
The present invention seeks to overcome these
disadvantages by proposing a new device which, on the
one hand, is able to ensure perfect sealing of the
device by preventing any leaks to the lower airways
25 and, on the other hand, is able to allow air to
circulate in both directions to allow the patient to
breathe and to perform the functions of speech and
swallowing. In addition, the novelty of this invention
which is detailed hereinbelow lies in the fact that the
30 device according to the invention has excellent
resistance to wear and to deformation under
physiological conditions and exhibits a life that is
far longer than the devices of the prior art.
35 To achieve this, the present invention proposes a novel
approach compared with the flap valve device described
in the patent application EP 08872036. In order to
develop a device which is more resistant and performs
better in a physiological environment, the inventors
have proposed to machine components from biocompatible
metal, which are then combined with one another to form
a sealed shutter. The biocompatible metals known to
5 date are titanium or titanium-based alloys, gold or
gold-based alloys, and platinum or platinum-based
alloys, niobium and tantalum or alloys of these. The
device made of a semi-rigid material described in
patent application EP 08872036 is easy to manufacture
10 by molding or injection-molding for example, because
semi-rigid materials are easy to work and are flexible.
Wishing to produce a flap valve device from solid metal
that is intended to be implanted within a dysfunctional
larynx represents a real technical challenge. This is
15 because the prior art in the field of tracheal
implants, whether these are implanted via a tracheotomy
or via an endo-buccal route, leans rather toward the
use of semi-rigid materials because these can be folded
for the purposes of insertion in order to be the least
20 traumatic possible both to the implantation tissues and
to the anatomical areas through which they will pass
before the device is in place. By contrast, in the
field of prostheses or implants that require high
mechanical stresses such as bone implants, there is a
25 leaning toward the use of rigid materials, including
metallic materials. However, said implants or
prostheses are not in motion and are there to stabilize
or encourage bone growth. The present invention goes
against the prior art in the field of laryngology by
30 developing a flap valve device, which therefore
involves moving parts, mainly made out of solid metal.
The subject matter of the invention is particularly
innovative because it offers exceptional life span, is
35 particularly good at resisting deformation and is also
able to allow air to circulate during inhalation and
exhalation phases while at the same time protecting the
lower airways by shutting off when needs be; thus the
functions of swallowing, breathing and speech are
restored in a lasting fashion.
More particularly, the present invention relates in
5 general to a flap valve device forming an
intralaryngeal prosthesis made of biocompatible solid
metal and intended to be implanted in a dysfunctional
larynx, said device comprising a distal portion forming
an annular bearing structure and a central portion
10 forming a shutter intended to allow air to pass and to
hermetically prevent any other element from passing,
said device being characterized in that the shutter
comprises i) a peripheral part forming a first valve
flap secured to the annular bearing structure at a
15 first hinge region, and ii) a central part forming a
second valve flap secured to the first valve flap at a
second hinge region, said first and second valve flaps
collaborating with one another in a completely hermetic
manner.
2 0
The invention will be better understood in the light of
the following examples and the following figures, in
which the bracketed references relate to the figures
appended to the present description.
25
Fig. 1 describes a profile view of a device (1) forming
an intralaryngeal prosthesis for a dysfunctional larynx
according to the invention. It shows the annular
bearing structure (2) the upper part of which is
30 equipped with valve flaps forming a shutter and the
lower part which is equipped with a silicone skirt (9),
intended to be fitted into the larynx, at the top of
the trachea. It also depicts the various parts that
make up the skirt ( 9 ) , namely the first part (12) fixed
35 to the annular bearing structure, the second part (13)
and the third part (14) which is in the shape of a
bevel (15). Lugs (16) aimed at blocking the prosthesis
once it has been implanted can be seen on the exterior
part of the skirt (9).
Fig. 2 is a view in vertical section of the upper part
5 of a device (1) forming an intralaryngeal prosthesis
for a dysfunctional larynx according to the invention.
It shows the annular bearing structure (2) in the upper
part of the device (1) and the collar or skirt (9)
fixed to the lower part of the annular bearing
10 structure (2). The large valve flap (4) and the small
valve flap (5) are borne by the annular bearing
structure (2) and are articulated about a hinge zone
(3). In this embodiment, the hinge zone (3) is a rigid
pin which fits into a cutout made in the valve flaps
15 (4) and (5). Limit stop elements (10) allow the valve
flaps to be blocked depending on the embodiment chosen.
The valve flaps (4) and (5) in the closed position form
a shutter (11).
20 Fig. 3 is a view from above of the device (1) which
forms an intralaryngeal prosthesis according to the
invention. It shows the large valve flap (4) and the
small valve flap (5) and the circumference of the
annular bearing structure (2). It also shows the hinge
25 zone (3) which corresponds to a model like the one
described in fig. 2, namely a hinge with a rigid pin.
Fig. 4 describes a view in vertical section of the
upper part of the device (1) that forms an
30 intralaryngeal prosthesis for a dysfunctional larynx
according to the invention. It illustrates the shutter
formed by the valve flaps (4, 5) in the horizontal
position, the limit stops (lo), a first hinge zone (3),
a second hinge zone 3 , a fixing plate (6) and the
35 annular bearing structure (2) and the collar or skirt
(9). This model details a hinge zone made from a semirigid
material which takes the form of a tab fixed to
the valve flaps (4) and (5) at one of its ends and
blocked by the plate (6) at its other end. The valve
flaps (4) and (5) in the closed position form a shutter
(11).
5 Fig. 5 is a view from above of a device (1) forming an
intralaryngeal prosthesis according to the invention.
It shows the large valve flap (4) and the small valve
flap (5) and the circumference of the annular bearing
structure (2). It also shows a first hinge zone (3) and
10 a second hinge zone (3') which corresponds to a model
like the one described in fig. 4, namely a semi-rigid
hinge.
Fig. 6 describes a view in vertical section of the
15 upper part of the device (I) that forms an
intralaryngeal prosthesis for a dysfunctional larynx
according to the invention. This is the model described
in figs 4 and 5, namely a model with a semi-rigid
hinge. It illustrates the shutter formed by the valve
20 flaps (4) and (5) in a horizontal position, the limit
stops (lo), the hinge zones (3) and 3 the
assistance elements (7, 8), the fixing plate (6) and
the annular bearing structure (2) and the collar or
skirt (9). The assistance elements encourage the valve
25 flaps to close.
Fig. 7 is a graph describing how the sticking forces
change as a function of the number of breathing cycles
performed in the case of the small valve flap (5).
3 0
Fig. 8 is a graph describing how the sticking forces
change as a function of the number of breathing cycles
performed in the case of the large valve flap (4).
35 The device according to the invention is made up
predominantly of biocompatible solid metal such as
titanium or titanium-based alloys, gold or gold-based
alloys, and platinum or platinum-based alloys, niobium
and tantalum or alloys of these or more generally of
any other biocompatible solid metal.
In a preferred embodiment, the metal used to
5 manufacture the annular bearing structure (2) and the
valve flaps (4) and (5) is titanium or a titanium-based
alloy. This is because this material is perfectly
biocompatible and it is possible to manufacture
components of small size the thickness of which can
10 easily be mastered. The present invention describes a
flap valve device (1) intended to be implanted in a
dysfunctional larynx, by means of a silicone skirt (9),
said device comprising a distal portion forming an
annular bearing structure (2) and a central portion
15 forming a shutter (11) intended to allow air to pass
and to hermetically prevent any other element from
passing, the shutter (11) comprises i) a peripheral
part forming a first valve flap (4) secured to the
annular bearing structure (2) at a first hinge region
20 ( 3 ) , and ii) a central part forming a second valve flap
(5) secured to the first valve flap at a second hinge
region 3 , and a means forming a collar or skirt (9)
for fixing the intralaryngeal prosthesis into, and
removing it from, a dysfunctional larynx, situated
25 below the annular bearing structure (2), in which the
annular bearing structure (2) and the two valve flaps
(4) and (5) that form the shutter (11) are made of
solid metal, preferably titanium or a titanium-based
alloy.
30
The method of manufacturing the device according to the
present invention entails microtechnical skills. This
is because in order to ensure that the device according
to the invention and more particularly the shutter
35 seals perfectly, the various parts made of solid metal
need to be perfectly matched and the operation of the
valve flaps needs to be extremely precise and reliable
in terms of the repeatability of the movements. To
achieve that, each component is produced blith
particular care before being assembled ~11th the other
parts that make up the device according to the
invention. The hinge zone adopts an especial importance
5 insofar as its role is to allow the valve flaps to fall
and to rise in order to restore the functions of the
dysfunctional larynx in b~hich the device is inserted.
This role is repetitive and of high precision. This is
because, without a reliable hinge function, the device
10 would remain blocked either in the open position (with
no protection of the lower airv~ays) or in the closed
position (without the possibility of air circulating),
or the valve flaps blould be misaligned leading to an
absence of sealing when closed, leading to
15 complications that are serious for the patient. In the
present invention, the hinge zone needs to allow valve
flaps made of solid metal to open and needs to return
these to the closed position using a return force that
it applies. The hinge zone is therefore an articulation
20 zone which is either linked with the mechanical
properties of the material used or linked with the
operation of a mechanism that allows the movement.
In the present description, the expressions "valve
25 flap", "valve", "shutter" or even "flap valve" can be
used interchangeably to denote a moving part capable of
moving from a closed position, or shut-off position, to
an open position that allows air to pass.
30 The expressions "distal" and "central" have as their
frame of reference the center of the device according
to the invention. It therefore follows that the
expression "distal portion" refers to the portion
furthest from the center of the device as opposed to
35 the expression "central portion" which refers to the
portion closest to the center of said device according
to the invention.
The terms "semi-rigid" and "superelastic" are used with
reference to soft materials that have spont.aneous and
permanent rigidity properties or rigid materials that
have spontaneous and permanent elasticity properties.
5 In general, these materials permit a certain elasticity
without permanent deformation and therefore
spontaneously return to their initial shape. By way of
example of semi-rigid materials, mention may be made of
plastics, rubber, silicone, and by way of example of
10 superelastic materials, mention may be made of nitinol
(a nickel-titanium alloy).
In a preferred embodiment, the circular structure of
the two valve flaps is preferable because, for a given
15 size, it is this configuration that offers the widest
possible opening for the passage of the air. However,
such a shape is not in any way limiting and the device
according to the invention may exhibit other shapes or
structures, notably an ovoid cross section.
2 0
At rest, the valve flaps of the device according to the
invention nestle one inside the other in the same
plane. However, depending on the mode of collaboration
chosen, the set of two valve flaps falls during
25 inhalation whereas only the smaller valve flap rises
during exhalation, or alternatively the set of the two
valve flaps rises during exhalation whereas only the
smaller valve flap falls during inhalation.
30 Among the possible modes of embodiment, the two valve
flaps may have their travel blocked by a limit stop
(10) or by a system of magnetic type. It is also
conceivable to combine limit stop elements (10) with a
system of magnetic type.
35
Another way of explaining this is to state that the
invention relies on the collaboration of two valve
flaps (4) and (5) nestling one inside the other in the
same plane at rest, the set of two valve flaps falling
on inhalalion whereas only the smaller onc opens on
exhalation or alternatively the set of two valve flaps
opening on exhalation whereas only the central valve
5 flap falls on inhalation. When the two valve flaps (4)
and (5) are in the same plane at rest, they form a
shutter (11) which is hermetic.
The valve flaps (4) and (5) are made to work by the
10 raised pressure and reduced pressure in the lungs
during the exhalation and inhalation phases. In one of
the embodiments, during inhalation and because of the
reduced pressure prevailing in the lungs, the two valve
flaps (4) and (5) fall in the same movement. On
15 exhalation, because of the raised pressure prevailing
in the lungs only the small valve flap (5) opens toward
the outside of the device, the large valve flap (4)
remaining blocked on its seat. In another embodiment of
the present invention, during inhalation and because of
20 the reduced pressure prevailing in the lungs, the
central small valve flap (5) falls by itself, the large
valve flap (4) remaining blocked on its support. On
exhalation, because of the raised pressure prevailing
in the lungs, the two valve flaps (4) and (5) rise
25 toward the outside of the device in the same movement.
The guarantee of good fluidtightness of the trachea
upon closure of the valve flaps (4) and (51, combined
with a good mechanical strength in the device according
to the invention is a very important factor during
30 swallowing in order to prevent food or saliva from
entering the trachea and then the lungs.
In one particular embodiment, the valve flap (4) is
capable of falling under the effect of the reduced
35 pressure resulting from the patient inhaling, and the
valve flap (5) is capable i) of collaborating with the
valve flap (4) by falling but also ii) of rising under
the effect of the raised pressure exerted by the air
exhaled by the patient. In one particular embodiment of
the device (1) according to the invention, the internal
part of the valve flap (4) comprises at least one limit
stop element (10) preventing the valve flap (5) from
5 rising.
In another particular embodiment, the valve flap (4) is
capable of rising under the effect of the raised
pressure applied by the air exhaled by the patient and
10 the valve flap (5) is capable i) of collaborating with
the valve flap (4) by rising but also ii) of falling
under the effect of the reduced pressure resulting from
the patient inhaling. In one particular embodiment of
the device (1) according to the invention, the internal
15 part of the annular bearing structure (2) comprises at
least one limit stop element (10) preventing the valve
flap (4) from falling.
In one preferred embodiment of the device (1) according
20 to the invention, the limit stop element (10) consists
of the fact that the external circumference of the
first valve flap (4) of the -shutter (11) is cut with a
"downward" bevel, and that the internal circumference
of the annular bearing structure (2) facing it is also
25 cut with an "inverse upward" bevel, the two bevel cuts
collaborating with one another to block the rise of the
first valve flap (4).
As will become apparent from the examples below, one of
30 the features of the invention relies on the material
used from which to manufacture the annular bearing
structure (2) and the valve flaps (4) and (5) of the
device (1) according to the invention. This assembly is
also referred to as the active part of the device. The
35 thickness of the valve flaps (4) and ( 5 ) , their system
of articulation and their overall shape allowing
perfect sealing are also decisive factors in optimum
operation of the device (1). This is because since the
preferred material is solid titanium, the valve flaps
(4) and (5) have no elasticity unlike those described
in the prior art. The role of the hinge regions (3) and
(3') is therefore key to ensuring even and sufficient
5 movement according to the demands made by the patient.
Specifically, the hinge zone (3), whatever its
configuration according to the present invention, has a
direct influence on the ability of the device (1) to
fall or even to hold its position. This elasticity
10 needs to be evaluated so that the pressure
, corresponding to the thrust applied by food or by a
buildup of saliva, mucus or any other fluid can be
resisted to prevent it from entering the upper airways,
while at the same time the valve flap is capable of
15 falling or rising in response to an exhalation raised
pressure or to an inhalation reduced pressure.
In one preferred embodiment, the hinge regions (3) and
(3') are situated between the valve flaps (4) and (5)
20 and the annular bearing structure (2) to form just one
single hinge zone (3, 3') for the two valve flaps (4)
and ( 5 ) . Finally, in one particular embodiment, the
hinge regions (3) and (3') are made of a semi-rigid,
superelastic or rigid material. In the case of a hinge
25 zone made of a rigid material, this is, for example, a
metallic pin around which the corresponding valve flap
is articulated by means provided for that purpose
during the cutting-out of the component (see fig. 2).
In the case of a hinge zone produced in a semi-rigid or
30 superelastic material, this is, for example, silicone
(see fig. 4) or nitinol.
In the remainder of the description, the expression
'alimentary bolus" will be used to define not only any
35 element of said alimentary bolus but also mucus, saliva
or any other element or body that is foreign to the
upper and lower airways.
According to one preferred embodiment of the invention,
the device is characterized in that the annular bearing
structure (2) comprises at least one limit stop element
(10) preventing the first valve flap (4) from falling.
5 This limit stop element (10) performs a key role
because it makes it possible either to prevent any
movement of the first valve flap (4) downward folloriing
the inhalation of the patient, or to prevent any
movement of the first valve flap (4) upward folloriing
10 exhalation by the patent.
~ -
Said limit stop element (10) may consist of any means
that impedes and blocks the upward or dormward movement
of the first valve flap ( 4 ) , such as a lug projecting
15 over the entire internal circumference of the annular
bearing structure for example, or alternatively simply
arranged at one or more precise points on this
circumference.
20 In one particular embodiment, the limit stop element
(10) intended to block the movement of the valve flap
(4) either downward or upriard depending on the device
chosen is a particular cut of the external
circumference of the first valve flap (4) of the
25 shutter (11) and an inverse cut of the internal
circumference of the annular bearing structure (2) in
its top part. The two cuts are intended to collaborate
in such a way as to hermetically block the rising of
the valve flap (4). By way of example of such a limit
30 stop system that uses particular cuts, mention will be
made of the device made of a semi-rigid material such
as silicone described in European patent application
EP 08872036. The reverse operation to that described in
EP 08872036 may also be envisioned in the present
35 invention, namely for the valve flaps (4) and (5) to
collaborate to rise when the patient exhales. The valve
flap (5) will fall during inhalation. In the case of
such a system with a cut forming a limit stop (lo), a
bevel cut is preferred because it allows a better seal
to be afforded. However, any other shape that allows
such collaboration must of course also be considered to
be equivalent.
5
Such bevel cuts or cuts in any other equivalent shape
are perfectly feasible in a rigid material such as
titanium. This limit stop system (10) has the advantage
of being simple to implement, and avoids adding
10 additional elements to the device (1) according to the
invention, and notably to the active part of said
device.
As described in European patent application
15 EP 08872036, the cuts described hereinabove for
limiting the movement of the valve flap (4) with
respect to the upper part of the annular bearing
structure (2) can also be used to join the valve flaps
(4) and (5) together. The cuts will then be made on the
20 interior circumference of the valve flap (4) and on the
exterior circumference of the valve flap (5). Depending
on the embodiment chosen, namely whether the two valve
flaps (4) and (5) fall together or whether the two
valve flaps (4) and (5) rise together, the directions
25 of cut will be chosen to be "upward" or "downward".
As detailed hereinabove, the two valve flaps (4) and
(5) that form the shutter (11) are actuated only by the
effects of reduced pressure and raised pressure caused
30 by the patient's breathing and, on the other hand, need
to be immobile as a result of some other pressure such
as the weight of any foreign element that could, for
example, come from the alimentary bolus. In order to
meet this requirement, the thickness of the shutter
35 (11) is between 0.3 mm and 2.0 mm. In one particular
'embodiment, the shutter (11) has a thickness of 1.0 rnm
to 1.5 mm. In a preferred embodiment, the shutter (11)
has a thickness of 1.0 mm.
By comparison with the valves and/or valve flaps
described in the prior art and generally made of a soft
material such as silicone, the valve flaps (4) and (5)
5 according to the invention are made of solid titanium
or a titanium-based alloy and are fixed by a hinge
region to an annular bearing structure (2) likewise
made of solid titanium or a titanium-based alloy. These
valve flaps are therefore particularly able to resist
10 the arrival of fluids or of the alimentary bolus at the
device, while at the same time beginning to move with
the patient's breathing.
The weight of the alimentary bolus is estimated on
15 average at 7.0 g which translates to a pressure which,
on average, does not exceed 3.10-~ MPa. The alimentary
bolus is made up of partially or fully chewed food
impregnated with saliva. After it has been sr.~allowed,
this alimentary bolus will travel along the esophagus
20 before finally reaching the stomach. Its mass will
break up to some extent following chewing and
swalloriing and according to the nature and weight of
the foodstuffs of which it is made, and the swiftness
of its path along the esophagus will similarly vary.
25 Under physiological conditions, it may therefore be
reasonably considered that not all of said alimentary
bolus will reach a specific point of the device
according to the invention at the same time. The flap
valve device according to the invention is designed to
30 resist an average load of 7.0 g, and this is easily
enough for correct operation of the flap valve device.
Moreover, the raised pressure applied when the patient
exhales and the reduced pressure applied when he
35 inhales are of the order of lo-* MPa, namely in both
instances far greater than the average pressure applied
by the alimentary bolus, around 3.10-~ MPa. It b~ill
therefore be easily understood that the valve flaps (4)
and (5) can rise or fall without difficulty as the
patient breathes.
More specifically, the device according to the
5 invention is characterized in that the first valve flap
(4) or the second valve flap (5), depending on the way
in which the device works, and their hinges are
dimensioned so as to be able to withstand a load less
than 4.0 g without rising and/or falling, depending on
10 the embodiment of the invention chosen.
In an alternative form, it may be desirable for the
resistances of the two valve flaps (4) and (5) to
differ so as to be able for example to adapt to suit
15 patients presenting respiratory problems that lead to
differences in pressure between inhalation and
exhalation. In this specific case, the dimensions of
the two valve flaps (4) and ( 5 ) , and of the
corresponding two hinge regions (3) and 3 , may
20 differ.
In general, it is preferable for the first valve flap
(4) and the. second valve flap (5) and the first (3) and
second (3') hinge regions to have the same thickness.
25 This avoids there being protruding zones which could
cause fluid or undesirable residue to build up.
Moreover, this last form of embodiment has numerous
advantages, for example reduction in manufacturing
costs.
3 0
In a preferred embodiment according to the invention,
in order to increase the resistance to the pressure
applied by fluids while not preventing the operation of
the valve flaps (4) and (5), an assistance device,
35 which may be mechanical, electrical or electronic, is
used. Said assistance device (7, 8) is placed at the
annular bearing structure (2) and/or at the first valve
flap (4). The present invention also relates to a flap
valve device (1) for an intralaryngeal prosthesis of
which the annular bearing structure (2) and/or the
first valve flap (4) are provided with an assistance
device (7, 8) that can be mechanical, electrical or
5 electronic.
In one particular embodiment, the assistance device (7,
8) described hereinabove is a magnetized device. What
is meant by a magnetized device or a magnetized element
10 is one or more permanent magnets of the lanthanide type
which are biocompatible or rendered biocompatible by
various treatments known to those skilled in the art,
or alternatively hermetically sealed in a suitable
housing provided for that purpose. Said magnetized
15 device may be positioned either on the first valve flap
or on the internal surface of the bearing structure of
the device according to the invention. Placed facing
the magnet or magnets when the first valve flap is in
the closed position, is a metallic element. What is
20 meant by metallic element is one or more metallic
elements that can be magnetized which are placed in
such a way as to come into contact with the magnet or
magnets when the first valve flap is in the closed
position. The nature of the magnetized device may be
25 adapted to suit each situation by varying the number of
magnets and/or their position for example. It may also
be conceivable to use two magnets facing one another.
In one particular embodiment, the present invention
30 relates to a flap valve device for an intralaryngeal
prosthesis (1) comprising an assistance device (7, 8)
which consists of a metallic element positioned at the
annular bearing structure (2) coming into contact with
a magnetized element arranged at the first valve flap
35 (4).
In one preferred embodiment, the present invention
relates to a flap valve device for an intralaryngeal
prosthesis (I) comprising an assistance device (7, 8)
which consists of a metallic element positioned at the
first valve flap (4) coming into contact with a
magnetized element positioned at the annular bearing
5 structure (2).
As described hereinabove, a mechanical assistance
device can be positioned on each of the valve flaps to
make it easier for them to cooperate in the desired
10 operation. According to this embodiment, the present
invention describes a device in which the first valve
flap (4) and the second valve flap (5) comprise an
assistance device so as to allow the rising of only the
second valve flap (5) and the simultaneous falling of
15 the first valve flap (4) and of the second valve flap
(5). In another embodiment, the valve flaps (4, 5) of
the device according to the invention comprise an
assistance device so as to allow the falling of only
the second valve flap (5) and the simultaneous rising
20 of the first valve flap (4) and of the second valve
flap (5).
The magnetized device described hereinabove has a
function of mechanically assisting the flap valve
25 device (1) according to the invention. More generally,
it will be easy for a person skilled in the art to
replace or supplement this magnetized device with any
device that performs an equivalent function or is
capable of improving this function, such as another
30 assistance device that may be mechanical, electrical or
electronic.
Furthermore, it is possible for the hinge regions (3)
and (3' ) and the valve flaps (4) and (5) not to have
35 the same thicknesses, it being possible for these
thicknesses to be adapted to suit a specific situation
dictated by the actual condition of the patient.
In order to be able to ensure the movement of the valve
flap or flaps while at the same time maintaining
perfect sealing, the hinges (3) and (3') need to be
made from a semi-rigid or even a rigid material.
5 Optimizing hinge regions made from a semi-rigid or
rigid material requires a very special approach because
it is necessary both for movement to be rendered
possible with a low respiratory pressure and also for
the hinges to allow the valve flaps to resist the
10 pressure of the alimentary bolus or of any fluid that
might press against the shutter with a varying degree
of force. Moreover, as stated hereinabove, it is
necessary for the hinges to resist colonization and to
provide smooth and lasting movement of the valve flaps.
15 In addition, the hinge zone needs to ensure perfect
stability of the rotation pins with respect to the
bearing structure of the device so as to guarantee
sealing on closure. The present invention proposes
several types of hinge capable of meeting all these
20 mechanical requirements. The principles of operation
when choosing a semi-rigid material, a superelastic
material or a rigid material will not be the same.
In the first instance, a semi-rigid or a superelastic
25 material means in the present invention a material that.
is soft enough to be able to provide a certain degree
of elasticity while at the same time being rigid enough
to be able to resist and remain in shape under the
effect of a small pressure. Such a semi-rigid material
30 may be selected from plastics, rubber, a resin or even
silicone. A superelastic material such as nitinol may
also be envisioned. A preferred material is 70 Shore A
silicone. The hinge then consists of a tab of silicone
fixed to the exterior part of the annular bearing
35 structure (2) by two studs and of a solid titanium
plate (6). The other end of the semi-rigid tab is fixed
to the valve flaps (4) and (5) by any suitable means.
By way of example, mention will be made of the
perforating of a small part of the valve flap, creating
orifices into which the semi-rigid material will flow.
This mechanism has the benefit of being perfectly
functional and biocompatible. In one particular
5 embodiment, the present invention describes a flap
valve device (1) comprising a distal portion forming an
annular bearing structure (2) and a central portion
forming a shutter (ll), the shutter (11) comprises i) a
peripheral part forming a first valve flap (4) secured
10 to the annular bearing structure (2) at a first hinge
region (3), and ii) a central part forming a second
valve flap (5) secured to the first valve flap at a
second hinge region 3 and a means forming a collar
or skirt (9) for fixing the intralaryngeal prosthesis
15 into, and removing it from, the dysfunctional larynx
situated below the annular bearing structure (21,
characterized in that the annular bearing structure (2)
and the two valve flaps (4) and (5) that form the
shutter (11) are made of solid metal, preferably made
20 of titanium or a titanium-based alloy and that the
hinge regions (3, 3') are made of one or more semirigid
or superelastic materials.
In the second instance, the hinge will be made from a
25 rigid material. A rigid material means a mechanism such
as a mechanical hinge, consisting of a rigid pin which
fits into a cut made in the valve flaps (4) and (5).
The rigid pin may be made of ruby or from a metal such
as titanium or a titanium-based alloy or any other
30 rigid biocompatible metal. More generally, a11 the
mechanisms used in horology and made from biocompatible
materials can be used in implementing the present
invention. This mechanism has the benefit of being
robust because it is made of materials that are rigid
35 and biocompatible which deteriorates little if at all.
In one preferred embodiment, the present invention
describes a flap valve device (1) comprising a distal
portion forming an annular bearing structure (2) and a
central portion forming a shutter (ll), the shutter
(11) comprises i) a peripheral part forming a first
valve flap (4) secured to the annular bearing structure
(2) at a first hinge region (3), and ii) a central part
5 forming a second valve flap (5) secured to the first
valve flap at a second hinge region 3 , and a means
forming a collar or skirt (9) for fixing the
intralaryngeal prosthesis into, and removing it from,
the dysfunctional larynx situated below the annular
10 bearing structure (2), characterized in that the
annular bearing structure (2) and the two valve flaps
(4) and (5) that form the shutter (11) are made of
solid metal, preferably of titanium or titanium-based
alloy and that the hinge reyions (3, 3') are made of
15 one or more rigid materials.
The means forming a collar or skirt (9) which is
situated below the annular bearing structure (2) has
the role of allowing the intralaryngeal prosthesis to
20 be placed and held within a dysfunctional larynx. This
skirt (9) is made up of three parts. The first part
(12) is situated at the top of the device (1) and fixed
to the annular bearing structure (2) using holes that
allow optimal bonding with the material of which said
25 skirt (9) is made, the second part (13) of a smaller
diameter than the first part (12) is situated below the
latter, and finally the third part (14) of a diameter
greater than that of the part (13) is situated below
the second part (13) and comprises a bevel or cone-
30 frustum cut (15). The variations in diameter between
the three parts make it possible to ensure that the
prosthesis once implanted remains in an axial position
because this allows it to adapt to suit the geometry of
the patient's anatomy.
3 5
The skirt (9) can be made of any biocompatible semirigid
material. It can be made of a material which is
solid or in the form of a spring or "stent". In one
preferred embodiment, the skirt (9) is made of
silicone. This is becausc since silicone is deformable
it allows the skirt to penetrate the orifice of the
larynx, of the cricoid cartilage and the vocal cords
5 and thus position the third part (14) at the top of the
trachea, the cricoid cartilage and the vocal cords
being situated level with the second part (13) and the
first part (12) lying above the previous two. The upper
plane of the prosthesis is then situated approximately
10 at a distance of between 10 mrn and 15 mm above the
plane of the arytenoid cartilage. The bevel (15) or
cone frustum makes it easier for the entire device (1)
according to the invention to enter the patient's
larynx.
15
The skirt (9) made of silicone is also provided with
lugs (16) intended to block the prosthesis against
translational and rotational movement once it is in
position within the patient's larynx. The inside
20 diameter of the skirt (9) allows the passage of a
6.0 rnm diameter cannula so that medical examinations
can be performed if required. Finally, the inside of
the skirt (9) has a planar additional thickness over
the entire height of the device (1) according to the
25 invention so as to increase the rigidity of the device
(1) while it is being implanted. Most of the sharp
corners of the skirt (9) are rounded to make them nontraumatic
on the one hand, and to make removal of
mucosities from the lower airways to the pharyngeal
30 zone easier on the other.
EXAMPLES
Various tests have been conducted on two intralaryngeal
35 prostheses for a dysfunctional larynx according to the
invention in order to ensure that their mechanical
properties meet the needs of the patients. These tests
consist of a fatigue test on the articulation or hinge
zone (3, 3') of the device according to the invention,
of a leak test testing the sealing of the valve flaps
against liquids and of a shutter (11) sticking test.
The model of flap valve device according to the
5 invention tested here has the following
characteristics:
- the hinge regions (3) and (3') are situated on the
same side of the device;
- the articulation or hinge region (3, 3') is made of
10 silicone.
~~ .
1. Articulation fatigue test
The valve flaps (4) and (5) are secured to a silicone
15 articulation (3, 3') fixed to the titanium annular
bearing structure (2) of the flap valve device that
forms the intralaryngeal prosthesis (1). This
articulation (3, 3') allows the valve flaps (4) and (5)
on the one hand to be at rest in the closed position
20 and on the other to allow the small valve flap (5) to
open downward, during inhalation, and allow the large
valve flap (4) and the small valve flap (5) to open
simultaneously upward during exhalation.
25 In a patient at rest, the rate of breathing is on
average 12 times per minute, namely 720 times per hour
and 17 280 times per day or 518 400 per month. If an
implantation life of at least 3 months in patients is
considered, with a factor of safety of 2, that
30 represents 3 110 400 breathing cycles and therefore
loading cycles on the silicone articulation (3, 3').
In order to make sure of the factor of safety, the two
devices according to the invention tested were
35 subjected to a pneumatic test opening and closing the
valve flaps (4) and (5) at a frequency of 2 Hz and
sometimes of 1 Hz for a duration in excess of 4 million
cycles. Table 1 below shows the results of the test for
one of the devices according to the invention, with
detailed observations under a binocular on each
stoppage.
Table 1: articulation fatigue test
step Start of phase End of phase Duration of
(date and time) (date and time) phase
(h:min:s)
1 15/12/09 19:06 16/12/09 14:52 19:48:00
2 16/12/09 15:28 17/12/09 18:08 02:40:00
3 17/12/09 19:Ol 18/12/09 18:31 23:30:00
4 18/12/09 20:39 21/12/09 18:53 22:14:00
5 22/12/09 19:02 28/12/09 15:43 20:41:00
6 30/12/09 19:44 4/1/10 9:48 14:04:00
7 4/1/10 10:18 5/1/10 9:40 23:22:00
8 5/1/10 11:06 8/1/10 15:05 03:59:00
9 8/1/10 16:22 11/1/10 15:46 23:24:00
10 11/1/10 17:06 13/1/10 14:20 21:14:00
11 13/1/10 14:20 14/1/10 8:33 18:13:00
12 15/1/10 12:22 18/1/10 14:45 02:23:00
13 18/1/10 16:44 18/1/10 17:47 01:03:00
14 19/1/10 9:35 19/1/10 10:20 00:45:00
Frequency
(Hz)
Numbez of
cycles
performed
142 320
334 320
503 520
1 009 200
1 515 660
1 911 900
2 080 140
2 827 220
3 141 300
3 466 980
3 532 560
4 068 120
4 075 680
4 081 080
It will be noted that after more than 4 million cycles,
the two devices of the invention are intact, with no
beginnings of cracks in the silicone articulation (3,
10 3 The parts made of titanium show no alteration. The
two devices are moreover perfectly functional.
The only observations made are that a small amount of
peening occurs in the zones of contact between the
15 valve flaps and the annular bearing structure. However,
this has no impact on the operation of the device
according to the invention.
2. Valve flap leak test for sealing against liquids
As described in the description, the device according
to the inventjon is placed in the larynx. It is
therefore subjected to the passage of the alimentary
bolus and notably to the liquids which may be water or
5 liquids of various kinds.
This test is performed using a blotting paper. The
latter is weighed beforehand then placed under the
valve flaps (4) and (5). A certain quantity of water is
10 then poured over the valve flaps (4) and (5) kept in
the closed position and therefore forming a shutter
(11). The results are detailed hereinbelow in table 2.
In order to define an acceptance criterion that is
15 compatible with what is acceptable to the trachea under
physiological conditions, it was decided that the
increase in mass of the blotting paper has to remain
below 1% of the mass of water poured, corresponding to
the contents of 5 soupspoons, poured in succession,
20 namely around 62 grams of water.
This test was performed at each stoppage for observing
the condition of the articulation or hinge zone (3, 3')
and that of the valve flaps (4) and (5) during the
25 fatigue tests.
Table 2: Leak test for seal against liquids
Number of L1
1.leasured soaked length
cycles
.-c.--.2
Corresponding mass of
% leaks
1
The first leaks are measured after 1 500 000 breathing
5 cycles. The leakage percentages are very small but do
increase with the number of cycles performed.
The measured leaks are still at very low levels,
representing less than 0.28% for one of the devices and
10 less than 0.26% for the other device. That demonstrates
the good sealing of the two valve flaps (4) and (5)
forming a shutter (11) in each of the devices tested.
3. Sticking test
15
These tests are aimed at assessing the effect of
certain viscous products that the patient ingests on
the force necessary to open the two valve flaps (4) and
(5) during a breathing cycle. These tests were carried
20 out using a mixture of 50% honey and 50% water
likenable to the viscosity of a product made up of
honey and saliva during the swallowing phase. The
measurements were performed using a dynamometer during
each stoppage of the fat-igue tests for checks. Figures
7 and 8, which relate to the small valve fl.ap (5) and
to the large valve flap (4), show that the opening
force does not vary appreciably over the life of the
5 implant.
Fig. 7 shows that the opening force for the small valve
flap (5) does not vary appreciably over the life of the
device according to the invention.
10
Fig. 8 shows that the opening force for the large valve
flap (4) does not vary appreciably over the life of the
device according to the invention.
15 4. Cough test
These tests are aimed at checking that the devices
according to the invention, under the effect of a cough
reflex, will open properly to allow the expelled air
20 out and that they will return to their rest position,
forming the shutter (ll), without deformation so as to
prevent the alimentary bolus from entering the trachea.
This test was carried out by performing 100 impulses
corresponding to coughing during each of the stoppages
25 for checking of the devices during the fatigue tests.
The results showed that the implants maintained their
functionality and their integrity on completion of
these tests.
30 In general, the present description is aimed at
illustrating the invention in the clearest possible way
and any obvious embodiment modification must be
considered as being equivalent and, therefore, must be
considered as being covered by the claims that follow
35 which define the scope for which protection is sought.
CLAIMS
1. A flap valve device (1) intended to be implanted in
a dysfunctional larynx, said device comprising a distal
5 portion forming an annular bearing structure (2) and a
central portion forming a shutter (11) intended to
allow air to pass and to hermetically prevent any other
element from passing, the shutter (11) comprises i) a
peripheral part forming a first valve flap (4) secured
10 to the annular bearing structure (2) at a first hinge
region (3), and ii) a central part forming a second
valve flap (5) secured to the first valve flap at a
second hinge region 3 ) and a means forming a collar
or skirt (9) for fixing the intralaryngeal prosthesis
15 into, and removing it from, a dysfunctional larynx
situated below the annular bearing structure (2),
characterized in that the annular bearing structure (2)
and the two valve flaps (4) and (5) that form the
shutter (11) are made of solid metal.
2 0
2. The device as claimed in claim 1, characterized in
that the annular bearing structure (2) and the trio
valve flaps (4) and (5) that form the shutter (11) are
made of titanium or of a titanium-based alloy.
2 5
3. The device as claimed in either one of claims 1 and
2, characterized in that the hinge regions (3) and (3')
are situated between the valve flaps (4) and (5) and
the annular bearing structure (2) to form just one
30 single hinge zone (3, 3') for the two valve flaps (4)
and (5).
4. The device as claimed in any one of claims 1 to 3,
characterized in that the hinge regions (3) and (3')
35 are made of a semi-rigid, superelastic or rigid
material.
5. The device as claimed in either one of claims 3 and
4, characterized in that the hinge regions (3) and (3')
consist of a silicone tab blocked by a titanium plate
(6) and that orifices made in the surface of the valve
5 flaps (4) and (5) allow the passage of the silicone to
ensure firm anchorage of the tab.
6. The device as claimed in either one of claims 3 and
4, characterized in that the hinge regions (3) and (3')
10 consist of a rigid pin on which the two valve flaps (4)
and (5) are articulated.
7. The device as claimed in claim 6, characterized in
that the hinge regions (3) and (3') consist of a pin on
15 which the two valve flaps (4) and (5) are articulated,
said pin being made of a material selected from ruby, a
metal such as solid titanium or a titanium-based alloy,
or any other biocompatible metal.
20 8. The device as claimed in any one of claims 1 to 7,
characterized in that the internal part of the valve
flap (4) comprises at least one limit stop element (10)
preventing the valve flap (5) from rising.
25 9. The device as claimed in any one of claims 1 to 8,
characterized in that the internal part of the annular
bearing structure (2) comprises at least one limit stop
element (10) preventing the valve flap (4) from
falling.
3 0
10. The device as claimed in either one of claims 8 and
9, characterized in that the limit stop element (10)
consists of the fact that the external circumference of
the first valve flap (4) of the shutter (11) is cut
35 with a "downriard" bevel, and that the internal
circumference of the annular bearing structure (2)
facing it is also cut with an "inverse upward" bevel,
the two bevel cuts collaborating with one another to
block the rise of the first valve flap (4).
11. The device as claimed in any one of claims 1 to 10,
5 characterized in that the first valve flap (4) and the
second valve flap (5) comprise an assistance device so
as to allow the rising of only the second valve flap
(5) and the simultaneous falling of the first valve
flap (4) and of the second valve flap (5) .
10
12. The device as claimed in any one of claims 1 to 11,
characterized in that the first valve flap (4) and the
second valve flap (5) comprise an assistance device so
as to allow the falling of only the second valve flap
15 (5) and the simultaneous rising of the first valve flap
(4) and of the second valve flap (5).
13. he device as claimed in any one of claims 1 to 12,
characterized in that the means that forms the collar
20 or skirt (9) for fixing the intralaryngeal prosthesis
into, and removing it from, a dysfunctional larynx
situated below the annular bearing structure (2) is
made of sili-cone.
25 14. The device as claimed in claim 13, characterized in
that the means forming a skirt (9) is made up of a
first part (12) situated at the top of the device (I)
and fixed to the annular bearing structure (2) using
holes that allow optimal 1;onding with the silicone, of
30 a second part (13) of a smaller diameter than the first
part (12) situated below the latter, and finally of a
third part (14) of a diameter greater than that of the
part (13) and situated below the second part (13) and
which comprises a bevel cut (15), the exterior surface
35 of the skirt (9) being provided with lugs (16) and the
interior surface of the skirt (9) haviny a planar
additional thickness over its entire height.