PROTHESE MAMMAIRE ET METHODE DE PRODUCTION DE LADITE PROTHESE

PROSTHESIS OF FEMALE MAMMA AND THE METHOD OF PRODUCING THEREOF

Abrégé anglais

ABSTRACT OF THE DISCLOSURE:
A prosthesis of the female mamma comprises a spongy
hydrophilic polymeric material (advantageously based on
methacrylate or acrylate) surrounded by a surface formed
from a layer of homogeneous film having a similar
composition to the spongy hydrophilic polymeric material.
This film continuously passes into the spongy structure and
is connected with it by chemical bonds. The thickness of
the homogeneous film may be controlled and is advantageously
less than 0.5 mm. A method for producing this prosthesis of
the female mamma is by polymerization of a monomer mixture
for preparation of the spongy polymer in an open mold in
such a way, that a film from a soluble polymer based on
methacrylate or acrylate is formed in the mold, before its
charging with the monomer mixture. This is done by casting
the mold with a solution of the soluble polymer. Then,
after removing any solvent, the mold is charged with the
monomer mixture for preparation of the spongy polymer and
the mixture is allowed to polymerize in the presence of
oxygen, advantageously in air.

Revendications

The embodiments of the invention in which an
exclusive property or privilege is claimed are defined as
follows:
1. Prosthesis of female mamma from a spongy
hydrophilic polymeric material, wherein the whole surface of
the said prosthesis is formed by a layer of a homogeneous
film having a similar composition as the spongy hydrophilic
polymeric material, while the film continuously passes into
the spongy structure and is connected with the spongy
polymeric material by chemical bond.
2. A prosthesis according to claim 1, wherein the
thickness of the homogeneous film is less than 0.5 mm.
3. A prosthesis according to claim 1 or 2,
wherein the spongy polymeric material is based on
methacrylate or acrylate polymers.
4. Method for producing a prosthesis of female
mamma by polymerization of a monomer mixture for preparation
of a spongy polymer in an open mold, wherein a film of a
soluble polymer based on methacrylate or acrylate is formed
on the inner surface of the mold before charging with the
monomer mixture and, after removing a solvent, the mold is
charged with the monomer mixture for preparation of the
spongy polymer and the mixture is allowed to polymerize in
the presence of oxygen, advantageously in air.
5. The method according to claim 4, wherein the
mold is declined from the vertical axis by 1 to 45° during
polymerization.

Description

i
The present invention pertains to a prosthesis of the female
mamma and to a method of producing it.
Until now, silicon rubber has been most often used for
producing a substitution of the woman's breast. However
this material is impermeable to body liquors and metabolites
and therefore rather unsuitable as a prosthesis of the
female mamma. The above mentioned disadvantages were
avoided in Czechoslovak Patent no. 140,155, which describes
the manufacturing of prostheses of -the female mamma from
spongy gels based on glycol methacrylate. A disadvantage of
the latter prostheses is that tissues grow into the sponge
and calcificates are deposited causing hardening and weight
increase of the prosthesis.
A prosthesis of the female mamma through which a newly
formed ligament does not grow, is knownfrom Czechoslovak
Patent no. 177,661. This prosthesis consists of a coat
formed from a homogeneous gel which is filled with a spongy
gel or a liquid gel of the vitrous-body type to form a
separate part not connected with the coa-t. The complex and
expensive preparation of this prosthesis and also the fact
that the core and coat do not form an inseparable part and
that the core is released from the coat during motion (which
may lead to damage of the coat) are the disadvantages of
this prosthesis.
A subject of this invention is a prosthesis of female mamma
from a spongy hydrophilic polymeric material, advantageously
based on methacrylate or acrylate, where the whole surface
of the said prosthesis is formed from a layer of a
~ homogeneous film having the similar composition as the
spongy hydrophilic polymeric material. This film
; continuously passes into the spongy structure and is
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connected with -the spongy hydrophilic polymeric material by
chemical bonds. The thickness of the homogeneous film may
be con-trolled and advantageously amounts to less than
0.5 mm.
The prosthesis oE female mamma according to -the invention is
produced by polymerization of a monomer mixture for the
preparation of spongy polymer in an open mold in such a way,
that the film from a soluble polymer based on methacrylate
or acrylate is formed in the mold before its charging with
the monomer mixture by casting the mold with a solution of
the said soluble polymer and, after removing a solvent, the
mold is charged with the monomer mixture for preparation of
the spongy polymer, which is allowed to polymerize in the
presence of oxygen, advantageously in air.
During the polymerization of the spongy structure, a firm
chemical bond with the film of soluble polymer occurs and a
crosslinking agent, preferably present in the monomer
mixture for the spongy polymer, induces the subsequent
crosslinking oE the film from the soluble polymer. The film
in this way becomes no longer soluble. The polymerization
in the presence of oxygen (preferably in air), instead of
the commonly used polymerization in an inert atmosphere,
creates a layer of a homogeneous non-spongy polymer even at
the third free surface (back side) of the prosthesis. The
mold may be advantageously inclined from the vertical axis
by 1 to 45 during polymerization to create a slant surface
on the final product. The prosthesis than corresponds by
shape to a natural woman's breast. After completion of the
polymerization, the prosthesis is thoroughly washed in
water.
A known monomer mixture is used in the preparation of the
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spongy polymer. The mixture is, Eor example, 10 to 40% by
volurne of 2-hydroxye-thyl methacryla-te containing 0.1 to 2%
by volume of ethylene dimethacrylate and 60 to 90% by volume
of a water-miscible liquid, for example, glycerol.
The soluble polymer advantageously used is the polymer
produced according to the Czechoslovak Patent no. 141,101
(Hydron S) by polymerization of glycol methacrylate or
poly(glycol) methacrylate or the corresponding glycol
acrylate, containing 0.05 to 50% by weight of glycol
dimethacrylate or poly (glycol) dimethacrylate, up to a
conversion ratio higher than 90% in solvents whose
interaction parameter (with respect to the formed copolymer)
are lower than 0.5. The polymer is perfectly soluble in
cold methanol, dimethylformamide, formamide, tertbutylal-
cohol, dimethylsulfoxide, ethylene glycol and in hot ethanol
and n-propanol.
The prosthesis according to the invention meets all
requirements for biomedical materials. HumantiSSUeS do not
; grow into the prosthesis but form a ligament casing around
it which is not firmly connected with the prosthesis. This
prevents calcification of the prosthesis. The method for
producing the prosthesis is very simple and economically
advantageous.
The invention is further illustrated by the following non-
limiting examples of performance.
EXAMPLE 1
' An~ open glass mold having the shape of awoman's breast is
cast with a 10% solution of the soluble polymer prepared
according to Czechoslovak Patent no. 141,101, U.S. Patent
; 3 -
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no. 3,575,946 (Hydron S) in cellosolve (trade mark) or
methanol. The whole inner surface of the mold is wetted, and
the solvent is allowed to evaporate. A strong film results.
The mold prepared in this way is charged with a monomer
mixture consis-ting of 30 vol. -% of 2-hydroxyethyl metha-
crylate, containing 1 vol. -% of ethylene dimethacrylate,
and 70 vol. -% of a 10% aqueous solution of ammonium
peroxosulfate. The mixture is allowed to polyrnerize at a
temperature of 60 to 70C for 20-30 min in the presence of
air. After completion of the polymerization, the resulting
prosthesis is carefully removed from the mold. Residues of
the initiator and monomers are removed by washing in
distilled water. This operation is carried out until the
washings do not demonstrate any reaction for sulfate ions
and organic impurities. The final molding has a continuous
layer of a clear homogeneous gel on the whole surface, which
layer continuously passes into the inner spongy structure.
EX~MPLE 2
The procedure is the same as in example 1, with the
distinction that the mold, after charging with the monomer
mixture for spongy polymer, is inclined from the vertical
axis by 15. The resulting prosthesis has a bevelled back
surface and corresponds by its shape to a natural woman's
breast.
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