WO1991001116A1

WO1991001116A1 - A mainly prosthetic implant, with a surface impeding the formation of a natural fibrous membrane

Info

Publication number: WO1991001116A1
Application number: PCT/FR1990/000434
Authority: WO
Inventors: Xavier Louis Gabriel Latouche
Original assignee: Xavier Louis Gabriel Latouche
Priority date: 1989-07-21
Filing date: 1990-06-15
Publication date: 1991-02-07
Also published as: AU5935390A

Abstract

The implant should be placed under the surface tissues of a living organism. It is characterised by the fact that it comprises two opposite sides (2 and 6), one of which (2) has many irregular contours (3) irregularly arranged right along the aforementioned side (2) which is to be placed against the surface tissue, whilst the other side (6) is smooth. According to a particular embodiment, the two sides (2 and 6) are part of the same thin, dome-shaped element (1) with the side (2) covered in contours (3) being convex and the smooth side being concave.

Description

IMPLANT, ESPECIALLY PROSTHESIS, WITH A SURFACE CONTRARY TO THE FORMATION OF A NATURAL FIBROUS ENVELOPE

The implantation of a foreign corsp in the organism causes on the part of this one a reaction of more or less strong rejection according to the nature of the foreign body.

Some implants are weakly aggressive and the natural reaction is an encyst process which aims to isolate and exclude an implant that is too large and too resistant to be phagocytosed.

Among the most frequently used implants, mention may be made of skin expanders and prostheses, especially breast implants.

The rejection reaction results in the constitution of a capsule made up of collagen fibers of the same size, having a lamellar arrangement, without interfibrillary spaces and oriented parallel to the implant. The associated cellular reaction is marked by an influx of polynuclear cells and lymphocytes which gradually become scarce and are replaced by histiocytes and fibroblasts. Sometimes the capsule changes little and remains sufficiently deformable to create no gene for the patient. But sometimes, after a certain time following implantation, time which can vary between several weeks and several years, the capsule hardens in 40% of the cases, by contribution of collagens, mucopolysaccharides and proteins.

This hardening causes the formation of an annoying hull, even unbearable, according to the figures below which show that out of 100 implantations which cause the creation of a hull, this appears at the rate of:

24%, three months after implantation,

43%, six months after implantation,

65%, one year after implantation,

85, two years after implantation, 95%, three years after implantation.

Note that if the capsule has not hardened to form a shell within four years of implantation, it will no longer appear spontaneously but only, sometimes, as a reaction to a new intervention, notably exploratory. It is therefore, in any case, a phenomenon of a normal and inevitable nature, in that no preventive treatment is known to it.

However, we have tried to reduce the effects of encystment on breast prostheses in two different and, moreover, opposite ways:

- Some have thought of avoiding the formation of a shell around the prosthesis by coating the latter with an inert foam, for example made of polyurethane, with open cells, in order to make the elements of the shell absorb by the foam: collagens and fibroblasts. This route recommends having fibrous elements absorbed by the prosthesis.

- Others have tried to counteract the formation of the shell, by reducing the contraction effect which encloses the prosthesis as in a vice. This route recommends repelling fibrous elements. According to the first route, fully or partially spongy breast prostheses have already been produced. A prosthesis of this type known as "IVALON" was produced around 1949 in a derivative of polyvinyl alcohol and appears as a sponge. Another similar prosthesis, known as "POLYSTAN" was used in the 1950s and was made from a polyethylene derivative; it looks like a sponge made of straw.

Another technical solution coming out of the first route is described in patent US-A-3,366,975 which relates to a breast prosthesis comprising a pocket of smooth synthetic material, containing a fluid such as a gel and covered with a layer of foam. .

To illustrate the second route, mention may be made of US Pat. No. 4,264,990 which describes a breast prosthesis composed of a pocket of smooth synthetic material, containing a fluid such as a gel, and of a rigid rear face. This one was supposed to oppose an energetic resistance to the contraction and, by there, to prevent the transformation of the flexible capsule into hard shell. Mention may also be made of US-A-4,531,244 which describes a breast prosthesis having a plastic bag, containing a fluid such as a gel and bristling with large rigid protrusions and regularly distributed. It is not simply a question of providing a rough surface on the prosthesis but of making a real frame, providing for the regular geometrical arrangement of the protrusions.

The protrusions must have a certain height which is fixed at least one millimeter and an example recommends a height of four millimeters. This arrangement necessarily creates between the protrusions continuous spaces which are filled by the fibrous elements, so that one does not obtain a suppression of the shell. In addition, the height of the protuberances is absolutely critical because the recommended few millimeters are very insufficient if we really hope to obtain a perforated shell. Indeed, a capsule (and not a shell) has a thickness of approximately one millimeter, formed by a multicellular layer and regularly distributed collagen fibers, in parallel arrangement.

Such a capsule is tolerable and therefore does not have to be fought. The real ailments to combat are the hulls which have a greater thickness: 2 to 3 millimeters in 44% of the cases, more than 5 millimeters in 51% of the cases and more than ten millimeters in 5% of the cases.

We understand that the solution proposed by this patent is practically inapplicable because during implantation, no one can know if the organism will create a simple bearable capsule or a shell and, in this case, according to what thickness. The only possible prevention is therefore to implant a prosthesis having protuberances of at least ten millimeters, which will form reliefs quite sensitive to touch in 95% of the shell cases and 100% of the capsule cases. The feeling of such reliefs is simply intolerable.

The present invention departs from known solutions by providing a new structure, capable of opposing the actual formation of the shell. We attack the very cause of evil and we are no longer content to fight its effects. As a result, the invention makes it possible to produce not only breast prostheses but also prostheses of other types and skin expanders which are intended to be removed after more or less prolonged use and for which it is particularly important to prevent an encyst because it constitutes an obstacle to the removal of the implant.

To this end, the subject of the invention is an implant to be placed under the surface tissues of a living organism, characterized in that it comprises two opposite faces, one of which has a multitude of irregular reliefs and which are irregularly arranged over all the extent of said face, which is intended to be placed against the surface tissues, while the other face is smooth. According to other characteristics of this implant:

- the two faces belong to the same thin element;

- It has the shape of a cap, the face which has the reliefs being convex and the smooth concave face; - It is intended to be placed between a volume amplifying element and the surface tissues;

- it is fixed to the volume amplifier element.

- the volume amplifying element is a pocket which must receive a fluid such as a gel;

- The two faces are separated by a space to receive a fluid such as a gel, in order to constitute a volume amplifying element.

The invention will be better understood from the detailed description below, given with reference to the accompanying drawing. Of course, the description and the drawing are given only by way of an indicative and nonlimiting example.

Figure 1 is a schematic perspective view of an implant according to the invention, having the shape of a cap. Figure 2 is a schematic sectional view of the implant of Figure 1.

FIG. 3 is a schematic view showing the convex face of the implant of FIGS. 1 and 2.

Figure 4 is a schematic sectional view illustrating the application to a breast prosthesis of an implant according to the invention, associated with a separate volume amplifier element.

Figure 5 is a partial schematic sectional view of an implant associated, in accordance with the present invention, with a volume amplifier element. Figure 6 is a schematic sectional view illustrating the application to a breast prosthesis of an implant according to the invention and constituting a volume amplifying element.

To illustrate the invention, its application has been chosen for the production of breast prostheses. Referring to Figures 1 and 2, we see that the implant 1 is made of an inert material which has the shape of a cap with a thin continuous wall.

Its convex face 2 has a multitude of reliefs 3, so that its nominal thickness e_, which can be of the order of two millimeters, is increased irregularly, by zones of small extent, up to a maximum thickness E, which can be of the order of three millimeters.

As a systematic irregularity is sought to avoid the presence of any continuous space, certain reliefs 3 are relatively steep while others rather evoke more or less long and more or less tortuous undulations.

For the same reason, certain reliefs 3 are punctual while others are elongated, short or long, with or without ramifications. The reliefs 3 are arranged variously but are distributed over the entire extent of the face 2, so that there are practically no continuous spaces, especially along meridians. In FIG. 3, two meridians 4 and 5 have been shown by way of example and by following their layout, we verify that they intersect many reliefs 3. We can verify that this is true for any meridian plotted at hazard.

This arrangement is important because the fibroblasts attach to each other in successive layers and the contraction of the entire shell is done according to the meridians (and therefore concentrically).

By removing all continuity on side 2, we offer fibroblasts a tormented surface in all directions which is fatal to the natural effort of contraction.

In addition, the fibroblasts are elongated and, in order to form an encystment shell, they are intended to be placed one on top of the other like bricks with alternating joints, forming long continuous chains along the meridians. Here, the multiple orientations of the reliefs 3 prevent fibroblasts from organizing into lines and they cannot form a shell. The reliefs 3 necessarily create counterparts similar to hollows but, after placement in the body, and unlike foam implants, there is no deep penetration of fibrous tissue elements. Consequently, if necessary, the removal of the implant presents no particular difficulty. In ^contrast to the face 2, there is a concave 6 quite smooth surface which can slide on the members against which it is placed. Face 2, on the other hand, is attached to the loose connective tissue that forms between it and the rest of the glandular-fatty tissue of the breast.

The faces 2 and 6 can be connected by a single edge but, here, a variant has been shown according to which there is a peripheral edge 7 whose free edge 8 has a smaller perimeter than that of the natural edge 9. The implant conforms to the invention can be associated with a volume amplifier element 10 and, with the example shown, the element 10 has a shape and dimensions corresponding to those of a woman's breast.

In FIGS. 4 and 5, it can be seen that the element 10 is distinct and consists of a pocket 11 made of a sheet of waterproof synthetic material and of a silicone gel 12. The entire implant includes therefore the cap 1 and the element 10.

As is well known in itself, the element 10 can be implanted empty and filled with gel 12 after installation, by means of a valve (not shown) or else be implanted already filled.

The cap 1 can be fixed to the pocket 11, in particular by an adhesive which has been mentioned in FIG. 5 by the reference 13. In this way, a standard cap 1 can be used for elements 10 of several shapes and / or dimensions. In this regard, the border 7 as described and shown can be a nuisance, in which case it is removed. This can be done by providing for the presence or absence of the border 7 as soon as the cap 1 is manufactured, which is advantageously obtained by molding a synthetic material, in which case the mold is created by taking account of this border 7. We can also only make caps 1 with a border 7 and remove it at the time of use by cutting it with scissors. When the cap 1 is fixed to the element 10, they must necessarily be put in place simultaneously.

When the cap 1 remains independent of the element 10, they can be put in place one after the other, which requires a more restricted approach and, therefore, less damage to the body.

In Figure 4, we see in section a female breast containing a prepectoral implant according to the invention. The rear face 11a of the pocket 11 is smooth and placed against the pectoralis major muscle A, from which the cellulo-adipose tissue B constituting the mammary gland has been detached.

During bodily movements, the implant can therefore slide against the large pectoral A, while it is made integral with the cellulo-adipose tissue B by the interpenetration of the latter and of the reliefs 3.

According to another embodiment ^" shown in FIG. 6, the front face 2 is separated from the rear face 6 by a space which must receive the gel 12.

The implant is thus formed in a single piece which combines the cap 1 and the volume amplifying element 10.

Of course, here again, the fluid 12 can be introduced into the pocket of the element either before or after the assembly has been put in place.

The implant according to the invention has many advantages, since it is possible, at will, to associate or dissociate a support such as the volume amplifying element 10 and the face 2 provided with reliefs 3.

Currently, there is no known plastic and elastic product which can be implanted directly, that is to say without the interposition of a pocket with walls as tight as possible. But the research that is being conducted suggests that such products will one day be usable, thanks to which the volume amplifier elements will be easier to install and safer as to their durability. It may, then, place a cap 1 between the plastic mass ^posterior (located in the place of the element 10) and the fabric cellulignin adipose B. Of course, the invention can be applied to prostheses other than breast prostheses or to implants which are not prostheses at all, such as skin expanders implants.

* .o.

Claims

R E V E N D I C A T I O N S

1- Implant to be placed under superficial tissues of a living organism, characterized in that it comprises two opposite faces (2 and 6), one of which (2) has a multitude of irregular and irregularly arranged reliefs (3) over the entire extent of said face (2), which is intended to be placed against the surface tissues (B), while the other face (6) is smooth.

2- Implant according to claim 1, characterized in that the two faces (2 and 6) belong to the same thin element (1).

3- Implant according to claim 2, characterized in that it has the shape of a cap (1), the face (2) which has the reliefs (3) being convex and the smooth face (6) concave.

4- Implant according to claim 1, characterized in that it is intended to be placed between a volume amplifying element (10) and the surface tissues (B). 5- implant according to claim 5, characterized in that it is fixed to the volume amplifier element (10).

6- Implant according to claim 5, characterized in that the volume amplifying element (10) is a pocket to receive a fluid (12) such as a gel. 7- Implant according to claim 1, characterized in that the two faces (2 and 6) are separated by a space to receive a fluid (12) such as a gel, in order to constitute a volume amplifying element.

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