WO2009007526A1

WO2009007526A1 - Implantable site with access redistribution screen

Info

Publication number: WO2009007526A1
Application number: PCT/FR2008/000773
Authority: WO
Inventors: Jean-Paul Gilbert Ricol; Pascal Paganon
Original assignee: Compagnie Européenne D'etude Et De Recherche De Dispositifs Pour L'implantation Par Laparoscopie
Priority date: 2007-06-07
Filing date: 2008-06-06
Publication date: 2009-01-15
Also published as: FR2916980A1

Abstract

The invention relates to an implantable medical device (1) for the injection and/or the sampling of a fluid in an organism, and comprising a housing (2) inside which is formed a cavity (3) defined by a wall (4), an anti-puncture screen (30), said device being characterised in that said anti-puncture screen (30) has a continuous closed outline and includes at least a first deformable segment (31) as well as a second deformable segment (32), and in that the first deformable segment (31) is adapted to substantially recover its initial shape when the second deformable segment (32) is deformed by a needle (7) and conversely. The invention relates to implantable medical devices.

Description

IMPLANTABLE SITE WITH ACCESS REDISTRIBUTION SCREEN

TECHNICAL AREA

The present invention relates to the general technical field of devices intended to be introduced under the skin of a human or animal patient to be subsequently stitched with a hollow needle, through the skin of the patient, in order to Introduce and / or remove substances from the body of the patient while limiting the trauma associated with the reiteration of the bites.

The present invention more particularly relates to an implantable medical device for the injection and / or sampling of a fluid in a human or animal body, said device comprising:

a housing in which is formed a chamber delimited by a wall which has at least a first puncture zone and a second substantially opposite puncture zone, an anti-piercing screen designed to prevent drilling from one side of the housing through a needle penetrating the chamber through one of said puncture areas.

PRIOR ART

It is known to implant under the skin of a patient a medical device, called an "implantable site", intended to form a remote access point allowing the transfer of substances to or from the blood circulation network. tissues of an organ, or an inflatable implant such as a balloon or a constriction ring. Generally, such an implantable site is in the form of a housing in which is formed a chamber defined by a wall, said wall being at least partly designed to be pierced by a hollow needle for transferring, injection or puncture a fluid in said chamber.

For this purpose, the wall usually has a puncture zone formed by a self-sealing membrane, or "septum", made of an elastomeric material, so that the sealing of the site is preserved both when the needle passes through the wall when it withdraws from it, the hole formed by the needle closing in effect automatically during the extraction of said needle by self-healing elastic phenomenon.

Generally, the chamber communicates, through an outlet port, with a flexible catheter attached to the housing, so that the stitching area can be moved to an anatomical region more easily accessible than the area of destination or provenance of the transferred fluid.

However, it has been found that, once implanted, the site is likely to turn on itself under the effect of a constraint or shock.

In order to spare the patient a new surgical procedure intended to reposition the site, an implantable site has been devised comprising a chamber delimited by a cylindrical wall resistant to perforation and closed at each of its ends by a distinct circular septum. Thus, said site is in the form of a disk having two opposite puncture zones, one on its upper face and the other on its lower face, so that when one of said puncture zones rests on the subcutaneous tissue, the other puncture area is substantially opposite the skin of the patient. Advantageously, the chamber can therefore remain accessible in the event of a 180 ° turnaround of the site on itself.

However, this provision of the puncture areas exposes the site to a piercing through, resulting in a failure of the puncture or injection operation, or damage to the subcutaneous tissue.

That is why, in order to prevent the needle entering the chamber from again crossing the wall of the chamber substantially opposite its entry point, it has been proposed to dispose in the chamber a resistant screen to the perforation which obstructs the section of said chamber so as to lock the needle.

Although it can be satisfactory especially in terms of comfort and stitching security, both for the patient and the practitioner, such a screen system can however have some significant disadvantages.

In particular, the known screens may have relatively complex or bulky shapes, likely to increase the cost of manufacturing the site and / or the weight of the latter, to limit the useful volume of the chamber, or even to hinder the free flow of the fluid transferred.

Then, these screens may have moving or deformable parts which, because of the repeated requests to which the needles submit, are likely, under certain circumstances, to lock or break causing an irreversible malfunction of the site. SUMMARY OF THE INVENTION

The objects assigned to the present invention therefore aim at overcoming the aforementioned drawbacks and at proposing a novel implantable medical device intended for the injection and / or sampling of fluid in a human or animal body whose implementation is particularly safe and effective. reliable.

Another object of the present invention is to provide a new implantable medical device that is particularly simple, compact and lightweight design.

Another object of the invention is to provide a new implantable medical device that is particularly strong and durable.

Another object assigned to the present invention is to provide a new implantable medical device that has excellent accessibility and facilitates the performance of stitching by the practitioner.

Another object assigned to the invention is to propose a new implantable medical device whose implementation is particularly comfortable and atraumatic for the patient.

Finally, another object assigned to the invention is to provide a new implantable medical device whose manufacture is simple and inexpensive.

The objects assigned to the invention are attained by means of an implantable medical device intended for the injection and / or sampling of a fluid in a human or animal body, said device comprising: a housing in which is formed a chamber delimited by a wall which has at least a first substantially identical puncture zone and a second puncture zone,

an anti-piercing screen designed to prevent piercing through the casing by a needle penetrating the chamber through one of said puncture zones, said device being characterized in that the anti-piercing screen has an outline continuous closed defining a buffer cavity and comprises at least a first deformable section designed to deform, without being pierced, under the pressure of a needle penetrating the first puncture zone, and a second deformable section designed to deform, without being pierced, under the pressure of a penetrating needle by the second puncture zone, and in that the first deformable section is arranged to return substantially to its initial shape when the second deformable section is biased by a needle, and reciprocally.

SUMMARY DESCRIPTION OF THE DRAWINGS

Other objects, features and advantages of the invention will appear in more detail on reading the description which follows, and with the aid of the accompanying drawings provided for purely illustrative and non-limiting purposes, among which:

- Figure 1 illustrates, in an exploded perspective view, a first embodiment of an implantable medical device according to the invention.

FIGS. 2A, 2B, 2C, 2D and 2E illustrate, in schematic cross-sectional views, the operation of the first embodiment of an implantable medical device shown in FIG. - Figure 3 illustrates, in a perspective view, a second embodiment of an implantable medical device according to the invention.

- Figures 4A, 4B, 4C, 4D and 4E illustrate, in schematic cross-sectional views, the operation of the second embodiment shown in Figure 3.

BEST MODE OF REALIZING THE INVENTION

The invention relates to an implantable medical device 1 for the injection and / or the removal of substances in a human or animal body.

Such a device 1, also designated by the term "implantable site", is intended to be implanted surgically in the body of a patient, preferably under the skin of said patient, to form an access point for the patient. introduction or extraction of fluids within the body of said patient.

Said device 1 can be implemented and adapted for different uses.

In particular, the device 1 according to the invention may be designed for the injection and / or the removal of fluid in an organ or in the circulatory system, for example to allow the injection of drug substances. According to a particular variant of this application, said device 1 can be adapted to form an artificial vein or artery that the practitioner can prick through the skin, in the manner of a natural vein, in order to inject a therapeutic substance or take blood.

The device 1 according to the invention can also be adapted to supply implanted reservoirs associated for example with insulin or analgesic pumps. Said device 1 may finally be adapted for injecting and puncturing fluid into the inflatable or deflatable compartment of a surgical implant, such as an artificial sphincter, a balloon or a gastric ring intended to achieve a constriction of the stomach to fight against obesity.

In the following, it will be more particularly considered that the device 1 constitutes a hypodermic device, that is to say that it is intended to be positioned just under the skin of the patient, although said device can be implanted with other places in the patient's body and in a deeper way without departing from the scope of the invention.

According to the invention, the device 1 comprises a housing 2 in which is formed a chamber 3 which is intended to accommodate the fluid injected or removed.

Said chamber 3 is delimited by a wall 4 which has at least a first puncture zone 5 and a second substantially opposite puncture zone 6, both of which are designed to be pierced by a hollow needle 7 intended to be injected or punctured. the fluid in the chamber 3.

For this purpose, the wall 4 of the chamber 3 is preferably at least partially formed, at said puncture zones 5, 6, by a self-sealing membrane 10 made of elastomer, for example silicone, preferably prestressing in compression.

Said self-sealing membrane 10, or "septum", is able to ensure the sealing of the device 1, both during the sewing by the needle 7 that after the withdrawal of said needle 7, the orifice generated by the drilling of said membrane 10 by means of the needle 7 rebuyhant indeed automatically, by self-healing elastic, after extraction of the latter.

By the expression "substantially opposite", it is indicated that the first and second puncture zones 5, 6 are, in the sense of the invention, arranged in relation to each other so that it is geometrically possible to draw through the chamber 3 at least one direct path between an entry point M1 located in the first puncture zone 5 and an exit point located in the second puncture zone 6, that is to say that would be geometrically possible, in the absence of anti-piercing screen as described below, a needle 7 entering the chamber 2 by the first puncture zone 5 passes through the device from one side to the other. emerging from the chamber 3 by the second puncture zone 6.

More specifically, considering that the device 1 is implanted just under the skin of the patient and that the wall 4 has a proximal wall portion 12 facing the skin, a distal wall portion 13 oriented towards the deeper tissues and one or more sidewall portions 14 extending between the proximal wall portion 12 and the distal wall portion 13, the first puncture zone 5 may be (by convention) located at the proximal wall portion 12, while the second puncture area 6 may be located at the distal wall section 13 and / or one or both of the side wall sections 14.

In a particularly preferred manner, the first and second puncture zones 5, 6 are merged, or at the very least contiguous, to form a continuous puncture zone that is generally convex with respect to the outside of the device 1. In other words, the chamber 3, and more generally the device 1 will present the practitioner a projecting wall 4 bulging outwardly. Preferably, as is illustrated in FIGS. 1 and 3, the chamber 3 has a substantially cylindrical geometry with an extension axis, that is to say a generatrix, (XX ').

More generally, the implantable site as a whole, and in particular the wall 4, preferably have a substantially cylindrical geometry of axis (XX ').

The transverse section (base) of said cylinder may be substantially circular, or ellipsoid more or less flattened constant or variable radius along the axis of extension (XX ').

Particularly preferably, the chamber 3, and more generally the housing have a geometry of axis revolution (XX '). In addition, the wall 4 preferably has, in the directions normal to the axis of extension (XX '), a substantially constant thickness.

Furthermore, the chamber 3, and more generally the housing 2, preferably have a substantially elongated shape that extends substantially along the axis of extension (XX ').

Thus, the device 1 may in particular adopt a substantially ovoid shape, olive or barrel, cylindrical right, pear-shaped, etc.

It is remarkable that the base of the cylinder may also be in the form of a polygon, so that the chamber 3 is delimited by a polyhedron, without departing from the scope of the invention.

In addition, the cumulative angular coverage of the puncture zones 5, 6 around the axis of extension (XX ') is preferably greater than or equal to 90 °, more preferably greater than or equal to 180 °, and so even more preferential substantially equal to 360 °, the chamber 3 being in the latter case accessible in all directions of approach substantially normal to the axis of extension (XX ').

Advantageously, such a substantially rounded and rotationally invariant geometry simultaneously makes it possible to give the device 1 a substantially atraumatic contour and to guarantee accessibility to the chamber 3 even in the event of a reversal.

Preferably, the housing 2 also comprises end plates 15, 16 disposed substantially perpendicular to the axis of extension (XX ') to close the cylindrical chamber 3 at both ends.

Said end flanges 15, 16 are preferably rigid and resistant to perforation.

Advantageously, said flanges 15, 16 can grip the self-sealing membrane 10 so as to prestress it in compression along the axis of extension (XX ').

Furthermore, the device 1 preferably comprises a hollow end 20, for example fixed to one of the end flanges 15, 16, said endpiece being designed to put the chamber 3 in communication with a catheter 21.

In addition, in order to perfect the covering and the tightness of the device 1, it may comprise a casing (not shown) with rounded contours, preferably made of a silicone-type biocompatible elastomer material, which covers the casing 2. In addition, in order to ensure the reliability of its operation, the device 1 according to the invention comprises an anti-piercing screen 30 designed to prevent piercing through the housing 2 by a needle 7 penetrating the chamber 3 to through one of the puncture zones 5, 6.

More specifically, said anti-piercing screen 30 is arranged to prevent a needle 7 penetrating into the chamber 3 through the first puncture zone 5 out of said chamber 3 by again piercing the wall 4 through the second puncture zone 6 and vice versa.

According to an important characteristic of the invention, the anti-piercing screen 30 has a continuous closed contour which delimits a buffer cavity 40, and comprises at least a first deformable section 31 designed to deform, without being pierced, under the pressure of a needle 7 penetrating through the first puncture zone 5, as well as a second deformable section 32 designed to deform, without being pierced, under the pressure of a needle 7 penetrating through the second puncture zone 6.

By "closed continuous contour", it is indicated that, in the sense of the invention, the screen 30 has an uninterrupted structure, that is to say, not susceptible to being fractionated or pierced by the needle 7 and which prevents therefore said needle to penetrate within the space delimited by said contour.

In addition, said first deformable section 31 is arranged to return substantially to its initial shape when the second deformable section 32 is deformed by a needle 7, and conversely, the second deformable section 32 is arranged to return substantially to its original shape when the first deformable section 31 is deformed by a needle 7. It is remarkable that, within the meaning of the invention, when a deformable section 31, 32 has been deformed under the thrust of a needle 7, it does not spontaneously come back on its own, or at least not completely, to its original shape, as long as the other deformable section has not been solicited.

In other words, the screen 30 according to the invention can advantageously substantially retain its configuration in a durable manner after being deformed during a first penetration by the needle 7 into the chamber 3.

Therefore, during successive taps, as long as the needle 7 accesses the chamber 3 substantially by the same region of the wall 4, that is to say by the same puncture area, it is not necessary to deform the screen 30 at each penetration of the needle, since the passage is formed during the first puncture. Advantageously, the fatigue wear of the screen is thus avoided by limiting its exposure to alternating deformation stresses.

Preferably, as shown in the figures, the "initial shape", or "initial configuration", of the deformable sections 31, 32 preferably corresponds to a state in which said sections are situated substantially at a first distance di from the wall 4, and the "deformed" configuration corresponds to a state in which the deformable section considered is, at least in part, at a second distance d ₂ from the wall 4, said second distance d ₂ being greater than the first distance di .

It is remarkable that, according to an alternative embodiment, the first distance di is substantially zero so that α, ue the deformable sections are substantially contiguous to the wall 4 when they are in initial configuration, that is to say that the screen 30 substantially matches the internal contour of the wall 4 of the chamber 3. Of course, it is also conceivable that the screen 30 substantially reproduce the contour of the wall 4 homothetically and / or at a first distance di non-zero and substantially constant of said wall 4.

Thus, as is particularly illustrated in FIGS. 1, 2D, 2E, 4D, 4E, the passage of a deformable section 31, 32 from its initial configuration to its deformed configuration preferably corresponds to a depression of said deformable section towards the interior of the chamber 3, in the direction of penetration of the needle 7, so that a functional volume is created and substantially maintained between the wall 4 and the screen 30, allowing the penetration and the deflection of the Needle 7 inside chamber 3

(in a course substantially equal to d ₂ ).

More precisely, said functional volume thus released can be "borrowed" from the initial volume of the buffer cavity 40.

As such, it is remarkable that the device according to the invention guarantees a double anti-piercing security because, regardless of the access point taken by the needle 7, the screen 30 opposes said needle at at least two puncture-resistant layers, between which there is preferably still a portion of the buffer cavity 40, namely a proximal layer and a distal layer. For example, in case of penetration by the first puncture zone 5, said proximal and distal layers may be formed by the first and the second deformable section 31, 32 respectively.

Furthermore, if the screen 30 according to the invention is able to substantially retain its configuration as the stitching conditions remain substantially identical, said screen 30 is however advantageously designed to be reconfigured when the penetration conditions by a needle change, for example in case of reversal of the device 1 on itself.

In other words, the screen advantageously has an access redistribution means capable of reorganizing the distribution of said screen as a function of the conditions, in particular orientation, according to which the needle 7 approaches the device 1, to reallocate the functional volume vis-à-vis the new puncture area through which the device 1 is addressed.

Each deformable section according to the invention therefore has two distinct states that are substantially stable, one in initial configuration, the other in a deformed configuration, such that the contour of the screen 30 is variable, thanks to the mobility and or the inherently deformable character of its constituent elements.

According to a first preferred embodiment illustrated in Figures 1 and 2A to 2E, the first and the second deformable section 31, 32 are formed by a first flexible panel 41 and a second flexible panel 42 semi-rigid.

By "semi-rigid", it is indicated that each flexible panel 41, 42 is on the one hand sufficiently flexible to be able to work in deformation, and more precisely to flex from its initial configuration to reach its deformed configuration and vice versa, and on the other hand sufficiently rigid to keep each of these two distinct states in a stable manner, as long as its passage has not been forced towards the other state.

Preferably, in the initial configuration, the flexible panels will have a convex curvature (protruding) vis-à-vis the outside, while they adopt a concave shape (reentrant) in a deformed configuration. In addition, each flexible panel 41, 42 is preferably "bistable", that is to say that its initial configuration and its deformed configuration constitute two equilibrium positions and are separated by a plurality of unstable intermediate configurations distributed from and other a crossing threshold. In said unstable intermediate configurations, said panel tends to be resiliently biased towards either its initial configuration or its deformed configuration.

Thus, the flexible panels 41, 42 can form flip-flops so that when a needle 7 pushes one of said panels into the chamber and said panel reaches a position corresponding to its tilting threshold, the transition of the initial configuration to the deformed configuration continues spontaneously under the impulse of the panel itself, and vice versa during the return movement to the initial configuration.

Preferably, each stable position corresponds to an extreme position of end of travel, that is to say of the limit of deformation of the panel.

Furthermore, although it is conceivable that the flexible panels 41, 42 cooperate by a return mechanism using for example a lever, a linkage, sprockets or any other equivalent system, said panels 41, 42 will preferably be mounted in opposition so that they can hunt each other by direct contact.

Thus, as shown in Figures 2B-2E, the deformed configurations of the different panels will preferably be chosen such that they interfere with each other. More precisely, the recessed bulge adopted by a panel in deformed configuration will be sufficient to "encroach" on the area occupied by the other panel when the latter is in a deformed configuration. Of course, each panel 41, 42 may be made using a plurality, and in particular a pair, of overlapping plates or juxtaposed and articulated edge to edge relative to each other. The elastic return can in turn be ensured by one or more springs reported cooperating with two adjacent plates or between the plates and the housing 2.

However, particularly preferably, said bistable panels will each be formed in one piece and preferably made of a material inherently having a spring effect, such as a superelastic metal alloy based on nickel and titanium, a steel stainless, or a semi-rigid polymer such as POM or polyolefins.

Thus, the bistable or "blistering" effect can be obtained by means of a spring plate held at its ends and working in bending substantially in the middle.

For this purpose, the screen 30 is preferably provided with a plurality of support members 45 mounted fixed relative to the housing 2, such as axes, while the bistable panels 41, 42 are articulated by their ends around of these.

By the term "fixed mounted", it is indicated that said support members 45, apart from a possible rotational movement on themselves, are not likely to change their position relative to each other. on the one hand, and / or with respect to the chamber 3 or the wall 4 on the other hand. More specifically, said support members 45 are arranged to form anchoring points of the flexible panels capable of opposing to the penetration force of the needle 7 a mechanical strength so that said penetration force generates a deformation of the corresponding flexible panel. In addition, it is remarkable that the bistable effect can advantageously be obtained or reinforced by prestressing in compression the panels 41, 42, between two support members 45 to which they are attached, so as to force their deformation by buckling, by example on either side of the straight line which joins said support members, said line then corresponding substantially geometrically to the tipping threshold.

According to a preferred embodiment, the support members 45 are formed by rods substantially parallel to each other and to the extension axis (XX ').

Thus, the screen can advantageously be made, possibly in one piece, using a plurality of plates each forming a flexible panel, the support members 45 forming, for their part, joints joining said plates edge to edge .

It is remarkable that the captive ends of the flexible panels can be mounted in free pivot connection around the support members 45 so as to form hinges capable of accompanying, by journalling, the central deflection of said panels.

As illustrated in Figure 1, the support members 45 may advantageously extend to form bearings 46, preferably shouldered, intended to be housed in bearings 47 of conjugate form dug in the and / either of the end flanges 15, 16.

It is remarkable that the support members 45 can thus contribute to improving the mechanical strength of the site by forming a kind of rigid skeleton able to support the membrane 10 in order to avoid crushing or distension of the chamber 3. Thus, it is possible to confer on the said membrane 10 a thickness just necessary and sufficient to its shutter function, generally reducing the structure of the site 1.

Of course, the number, the arrangement and the distribution of the deformable sections vis-à-vis the puncture areas are subject to variations without departing from the scope of the invention.

Thus, preferably, as is illustrated for example in FIGS. 1 and 2A to 2E, the anti-piercing screen 30 may comprise a third deformable section 33 arranged to cooperate with the first and second deformable sections 31, 32 of FIG. such that the deformation of any of said deformable sections 31, 32, 33 causes the two other deformable sections to return to their original shape.

In other words, each section may in turn be depressed into a deformed configuration, but only one at a time.

In addition, the deformable sections 31, 32, 33 are preferably distributed substantially equidistant about the axis of extension (XX ') of the device 1.

More particularly, according to a variant comprising three deformable sections, these can be distributed in an angular pitch substantially equal to 120 °.

It is remarkable that such an arrangement allows if necessary to achieve said sections with flexible panels all identical which allows to standardize the manufacture.

According to a second preferred embodiment illustrated in FIGS. 3 and 4A to 4E, the screen 30 comprises a perforated reinforcement 60 presenting several windows 61, as well as a flexible sheet 62 resistant to perforation, which is on the one hand mounted so as to be able to circulate along said frame 60, and which on the other hand has a length substantially greater than the perimeter of said 60, so that said web 62 can be driven by the needle 7 through one or other of the windows 61.

Of course, said windows are for this purpose open substantially opposite the puncturing zones 5, 6, so as to allow the needle which leads to the web 62 to pass.

Thus, it is portions of the ply 62, and in particular the sheets of ply covering the windows 61, which form the deformable sections 31, 32, 33;

According to an alternative embodiment not shown, the perforated reinforcement 60 is formed by a tubular structure with a thin wall, such as a metal sheet wound on itself and substantially coaxial with the chamber 3, the windows 61 being formed by lights cut into the thickness of said wall, for example in rectangular patterns and parallel to the axis of extension (XX ').

According to an alternative embodiment corresponding to Figures 3 to 4E, the armature 60 preferably comprises a plurality of pillars 63 spaced from each other and substantially parallel to each other. The windows 61 can then be defined as the inter-pillar spaces.

In a particularly preferred manner, said pillars 63 extend parallel to the axis of extension (XX ') and join the end flanges 15, 16, so that the armature 60 advantageously contributes to stiffening the chamber 3, and more overall the housing 2. In addition, as shown in FIGS. 3 to 4E, the pillars 63, considered in a plane of section that is substantially normal to the axis of extension (XX '), are preferably substantially arranged at the top of a regular polygon, for example a square.

According to this same variant embodiment, the sheet 62 advantageously forms a closed circulating strip arranged outside the bundle of pillars 63, that is to say between said pillars and the inner wall of the chamber, said strip being free to move between the frame and the wall 4.

Advantageously, the excess length of the ply 62 provides a reserve of material which allows the depression of a portion of said ply to enter two adjacent abutments under the thrust of the needle 7.

Thus, as illustrated in particular in FIG. 4C, the sheet 62 can adopt, in use, an outline having a "soft" strand pressed inwardly between two pillars and a plurality of "stretched" strands. (in this case three) which substantially draw cords on the circular contour of the wall 4.

In this respect, it is remarkable that the greater the number of pillars 63, the more the polygon drawn by the stretched strands of the ply 62 tends to conform to the contour of the wall 4.

Furthermore, the pillars 63 may advantageously be mounted in free pivot relative to the flanges 15, 16, so that their rotation accompanies the movement of the sheet 62, in the manner of a roller / belt system, thus limiting the friction exerted on said sheet and consequently the wear of the screen 30. The web 62 may in particular be made of a puncture resistant textile material or in a kind of metal mesh size.

It is remarkable that the screen 30, and more particularly the web 62 or the flexible panels 41, 42 previously described are preferably porous, so as to allow fluid transfer across the screen, between the buffer cavity 40 and the the remainder of the chamber 3, that is to say in particular between the buffer cavity 40 and the clear functional volume or the possible interstitial space existing between the wall 4 and the screen.

The operation of a device according to the invention corresponding to the first embodiment detailed above will now be described with reference to FIGS. 1 to 2E.

Initially, at the factory outlet, the device 1 is as shown in FIG. 2A, the contour of the screen 30 substantially following that of the wall 4, that is to say that each deformable section 31 , 32, 33 is in its initial configuration.

For convenience of description, it will be assumed that the first penetration of a needle 7 into the chamber 3 takes place through the first puncture zone 5 as shown in FIG. 2B.

When said needle 7 enters the chamber 3 at an entry point M1, after passing through the membrane 10 by piercing it, its bevel meets the outer surface of the screen 30, and more particularly of the flexible panel 41 forming the first section deformable 31 located at a distance di from said membrane 10.

Under the combined effect of the penetration force exerted by the needle 7 which bears on it, and the restraint force provided by the organs of 45, the first flexible panel 41 flexes and is gradually pushed by sinking from the periphery to the heart of the chamber 3 until substantially reaching a second depth d ₂ .

According to a preferred embodiment comprising a first bistable flexible panel 41, as soon as the needle 7 has been sufficiently depressed to move the first panel 41 its tipping threshold, that is to say that the needle has penetrated into the chamber over a predetermined length substantially between di and d2, said first flexible panel 41 spontaneously continues its deformation movement, preceding the needle 7, to reach its deformed configuration.

Thus, a functional volume allowing the clearance of the needle 7 is taken from the initial volume of the buffer cavity 40, in this case by an inversion of curvature of the portion of the screen 30 corresponding to the first deformable section 31.

Once in deformed configuration said first deformable section 31 forms a stop against the progression of the needle 7 in the direction of penetration.

Said needle 7 is thus stopped when it strikes the first panel 41 which is in deformed configuration, the feeling of resistance indicating to the practitioner that the needle 7 has reached the heart of the chamber and that he can proceed to the injection or puncture.

Once the fluid has been transferred, the practitioner pulls on the needle 7 to extract it from the chamber 3. Due to the stable nature of the deformed configuration, the first panel 41 substantially retains its concave shape, which preserves the functional volume vis-à-vis the first puncture zone 5.

Thus, as long as the site has substantially the same face opposite the skin of the patient and the punctures are repeated at said first puncture zone 5, the screen 30 undergoes no significant change in its configuration, and in particular no deformation of its deformable sections.

On the other hand, if a needle 7 approaches the site by the second puncture zone 6, for example following a reversal of the device -1 on itself, the bevel of the latter strikes the outer surface of the screen at the level of the second deformable section 32, as shown in Figure 2D. Said second section is then deformed in flexion and pushed back until its inner face bears on the inner face of the first deformable section 31 which was in deformed configuration.

This interference causes a transfer of the penetration force of the needle 7 by direct contact, which causes the concomitant deformation of the second panel 42 and the first panel 41, so that the first panel 41 returns to its initial configuration, via a plurality of intermediate patterns shown in dashed lines in Figure 2E, while the second panel 42 is in its deformed configuration.

The return thus made makes it possible to transfer the functional volume necessary for the movement of the needle from the region of the chamber 3 situated at the level of the first puncture zone 5 towards the region of the space situated at the level of the second puncture zone. 6. It is remarkable that the use of bistable panels advantageously makes it possible to reduce the duration of contact of the bevel of the needle with the first deformable section 31 to the extent that it precedes the movement of the needle as soon as its tilting threshold has been crossed. . This minimizes the friction and wear effects of both the screen 30 and the bevel of the needle 7.

The operation of a variant of the device 1 according to the second embodiment illustrated in Figures 3 to 4E is based on a substantially similar principle of redistribution of the functional volume.

However, it differs from the foregoing in that the deformation of the deformable section concerned under the thrust of the needle is caused not by the flexion of a semi-rigid structure, but by the traction drive of a spare available. of flexible material.

More specifically, as illustrated in FIG. 4D, when the bevel of the needle comes to rest on the outer surface of the ply 62 at the level of a strand initially "stretched", that is to say forming substantially a rope between two consecutive pillars 63, it drives the sheet 62 by driving it into the window 61 formed between said pillars 63.

The call of matter caused by this deformation is compensated by the gradual recovery of a pool of length of web initially "stored" in the interstitial space between the pillars and the wall 4 and / or sunk between two other pillars, such as that is illustrated in Figures 4A to 4C.

Advantageously, the transfer of the sheet 62 takes place almost effortlessly by simply sliding, or rolling, on the surface of the pillars 63. In other words, the initially "soft" strand is gradually stretched while one of the strands initially "stretched" is gradually depressed, as is illustrated in Figures 4C to 4E, the contour of the screen 30, and more specifically each of the portions between two consecutive pillars 63, passing successively by a plurality of intermediate shapes shown in dashed lines in the figures.

Thus, the device according to the invention has excellent accessibility, substantially from all approach directions transverse to its axis of extension (XX ') and provides the needle 7 an important functional volume which ensures the proper penetration of the bevel in the chamber and there free flow of the fluid transferred inside the latter.

In addition, particularly advantageously, the device 1 according to the invention considerably reduces the fatigue of the elements that constitute the screen 30 by reducing the application of alternating stresses, the repetition of folding movements, or the friction between the bevel and the surface of said screen. The life of such a site 1 is therefore particularly high.

Finally, the simplicity of the structure of said device 1 allows to combine operational safety, lightness, and low cost.

POSSIBILITY OF INDUSTRIAL APPLICATION

The invention finds its industrial application in the design and construction of implantable medical sites.

Claims

Implantable medical device (1) intended for the injection and / or sampling of a fluid in a human or animal body, said device comprising: a housing (2) within which is formed a chamber (3) delimited by a wall (4) which has at least a first puncture zone (5) and a second substantially opposite puncture zone (6),

- an anti-piercing screen (30) designed to prevent piercing through the housing (2) by a needle (7) entering the chamber (3) through one of said puncture zones (5, 6) , said device being characterized in that the anti-piercing screen (30) has a continuous closed contour defining a buffer cavity (40) and comprises at least a first deformable section (31) designed to deform, without being pierced, under the thrust of a needle (7) penetrating through the first puncture zone (5), as well as a second deformable section (32) designed to deform, without being pierced, under the pressure of a penetrating needle (7) by the second puncture zone (6), and in that the first deformable section (31) is arranged to return substantially to its initial shape when the second deformable section (32) is biased by a needle (7) and reciprocally .

- Device according to claim 1 characterized in that the first and the second deformable section (31, 32) are formed by a first and a second flexible panel (41, 42) semi-rigid. 3 - Device according to claim 2 characterized in that the flexible panels (41, 42) are bistable. - Device according to claim 2 or 3 characterized in that the flexible panels (41, 42) are mounted in opposition so as to be chased mutually by direct contact.

5 - Device according to one of claims 2 to 4 characterized in that the flexible panels (41, 42) are made of a material having a spring effect, such as a super-elastic metal alloy based on nickel and titanium , a stainless steel, or a semi-rigid polymer such as POM or polyolefins.

6 - Device according to one of claims 2 to 5 characterized in that the screen (30) is provided with a plurality of support members (45) mounted fixed relative to the housing, such as axes, and the flexible panels (41, 42) are articulated by their ends around them.

7 - Device according to claim 1 characterized in that the screen (30) comprises a perforated reinforcement (60) by a plurality of windows (61), and a sheet (62) flexible perforation resistant which is mounted so that able to circulate along said frame (60) and whose length is substantially greater than the perimeter of the latter, so that said sheet (62) can be driven by the needle (7) through one or the other other windows (61).

8 - Device according to claim 7 characterized in that the armature (60) comprises a plurality of pillars (63) spaced apart from each other and substantially parallel to each other. - Device according to one of the preceding claims characterized in that the screen (30) substantially matches the inner contour of the wall (4) of the chamber (3).

- Device according to one of the preceding claims characterized in that the first and the second puncture zone (5, 6) are combined to form a continuous puncture zone generally convex vis-à-vis the outside of the device.

- Device according to one of the preceding claims characterized in that the anti-piercing screen (30) comprises a third deformable section (33) arranged to cooperate with the first and second deformable sections (31, 32) so that the deformation of any one of said deformable sections (31, 32, 33) causes the return of the other two deformable sections to their original shape.

-Dispositif according to one of the preceding claims characterized in that the chamber (3) has a substantially cylindrical geometry of extension axis (XX ') and in that the angular coverage of the puncture zones (5, 6) around said extension axis is greater than or equal to 90 °, preferably greater than or equal to 180 °, and particularly preferably substantially equal to 360 °.