Breast implant

A breast prosthesis implant is disclosed comprising a generally conical bio-compatible fabric shell. The shell is pervious to tissue growth and body fluids. The interior of the shell is divided into series of discrete chambers separated by pervious fabric dividers, the chambers containing masses of bio-compatible fibers. The fiber concentration in the chambers nearest the apex of the cone is less than the concentration in chambers progressively further from the cone apex. Preferably, the shell is somewhat stretchable to permit the volume of the shell to increase or decrease in accordance with the weight gain or loss of the patient.

BACKGROUND OF THE INVENTION 
The present invention is directed to a prosthetic device and specifically 
to an improved compound prosthesis intended to be implanted in a female 
breast following removal of diseased body tissue. 
Still more particularly, the invention is directed to a bio-compatible 
breast implant characterized in that following an initial period after 
implant provides the patient with a close simulation of a natural breast. 
PRIOR ART 
Numerous attempts have been made to provide an implantable breast 
prosthesis which resembles, both to the patient and to third persons, a 
close simulation of the normal breast. 
The use of liquid silicone implants is counter indicated in view of the 
deleterious effects which may result from silicone leakage. 
Implants comprised of silicone pouches filled with saline or the like are 
deficient in many respects. Specifically, since pouch must be only 
partially filled to avoid rupture, the weight of the liquid forms the 
slack pouch into visible ripples. Also, the temperature of the liquid is 
retained over protracted periods such that when the patient moves from a 
cold to a warm environment, for example, the implant will continue to feel 
cold. It is also possible, upon exposure to the sun, for actinic rays to 
penetrate the pouch and damage tissues normally protected by the healthy 
breast. 
Attempts have been made to fabricate implants from biocompatible materials, 
illustratively DACRON (a trademark of the Dupont Corporation). 
By way of example, U.S. Pat. No. 4,936,858 discloses a composite implant 
comprised of a net-like pouch of bio-compatible fabric which encompasses a 
further pouch filled with a gel in a silicone sack. The fabric material is 
selected to permit substantial in-growth of body tissues, so as to fix the 
prosthesis at the implant site. 
U.S. Pat. No. 3,293,663 discloses the use of a tissue pervious porous 
polyester fabric secured to the posterior surface of a silicone filled 
sack, the fabric functioning, upon tissue in-growth, to anchor the 
prosthesis. 
U.S. Pat. No. 3,189,921 discloses a foam type implant having a sponge shell 
whose outer surface is pervious to fibrous tissue and blood, the shell 
having an inner surface which is pervious to body fluids but impervious of 
cellular structure. The reference notes that prior foam implants were 
undesirable in that they permitted in-growth of fibrous tissues throughout 
the foam resulting in an implant which hardens. 
Each of the noted approaches to providing a "natural" breast implant have, 
for one or more reasons, failed to achieve commercial success. 
SUMMARY OF THE INVENTION 
The present invention may be summarized as directed to a prosthetic device 
intended specifically for use as a breast implant and characterized in 
that it presents no health hazard, is not subject to migration from the 
implant site, is comfortable to the patient and presents, both from an 
appearance and tactile standpoint, the characteristics of a natural female 
breast. 
An important feature of the device of the invention is that to a limited 
degree the implant is able to increase and decrease in size in accordance 
with the gain or loss of weight by the patient. Since new blood vessels 
and tissue will develop throughout the structure of the device normal body 
temperature will be maintained at the structure site in contrast to known 
liquid-filled prosthesis which vary from body temperature when subjected 
to cool or hot environments. 
Briefly stated, the prosthetic device of the invention is comprised of a 
bio-compatible structure comprised of a homopolymer polyester, 
illustratively fiber identified as FORTREL, polyester type 302, 
manufactured by WELLMAN INC. 
A characterizing feature of the device of the invention is that the 
prosthesis is comprised of a generally conical structure preferably of 
deformable warp knit fabric internally sub-divided into a series of 
chambers by generally parallel spaced fabric dividers extending generally 
perpendicularly to the axis of the conical structure. The dividers which 
are preferably resistant to stretching form the interior of the structure 
into a series of chambers, the chambers each containing a fill of 
bio-compatible fibers. 
The fibers and the fabric sub-dividing the chambers are selected such as to 
provide controlled permeability both to body fluids and tissue growth, the 
tissue growth in particular being controlled by the fiber density and to a 
lesser degree, the permeability of the dividers such that the degree of 
tissue in-growth into the various cells or chambers is greatest in the 
anterior chambers, tissue in-growth into progressively posteriorly related 
chambers being progressively less. 
The structure of the device is intended to promote a relatively high degree 
of tissue in-growth in the lower density fiber-filled anterior chambers 
with progressively lower in-growth in posteriorly located more densely 
fiber-filled chambers. 
More particularly, the fiber fill in the posterior chambers is effected to 
a higher density, with the respective chambers toward the anterior or 
nipple adjacent chamber being filled to a lower density of fiber. Both the 
external surface of the prosthesis and the dividers are pervious to body 
fluids, the external surface of the prosthesis being preferably fabricated 
of a velour type distensible and, to a degree, deformable knitted 
structure to assure rapid tissue in-growth to provide locational stability 
to the device promptly after implant. 
It is accordingly a primary object of the invention to provide a breast 
prosthesis which may be permanently implanted and which replicates, as 
nearly as possible, the characteristics of a natural breast. 
A further object of the invention is the provision of a prosthesis 
comprised of bio-compatible fabrics which obviates the disadvantageous 
aspects of prostheses heretofore known. 
A further object of the invention is the provision of a breast prosthesis 
characterized in that the same is divided into a series of chambers of 
progressively increasing base size in the configuration generally of 
frusto-conic structures, further characterized in that the chambers are 
all receptive to tissue in-growth as well as pervious to body fluids, and 
in that posteriorly located chambers are filled with progressively denser 
fibrous materials and are, hence, less receptive to tissue in-growth than 
anteriorly related chambers thereby to provide a device which closely 
replicates the characteristic of a natural breast. 
Still a further object of the invention is the provision of a prosthesis of 
the type described having an exterior surface comprised of velour like 
knitted material whereby to encourage the rapid in-growth of tissue into 
the knitted structure to promptly and permanently locate the prosthesis. 
A still further object of the invention is the provision of a breast 
prosthesis which, to a degree, is enabled to expand and contract in 
accordance e.g. with the gain or loss of weight of the patient whereby the 
body defines the shape of the structure, rather than the structure 
defining the shape of the body. 
A still further object of the invention is the provision of a prosthesis of 
the type described having a life expectancy coincident with the life of 
the patient, i.e. to eliminate the necessity for adjustment or replacement 
as is the case with implants heretofore known.

DETAILED DESCRIPTION OF DRAWINGS 
In FIG. 1 there is disclosed an implant or prosthesis 10 in accordance with 
the invention. Details of the specific fibers and like materials will be 
described in a further section of the instant application. 
Referring to FIG. 1, the prosthesis 10 is comprised of a generally conical 
configuration including a exterior, preferably warp knit and stretchable 
fabric 11, the external configuration of the anterior portion 12 being 
configured generally in a convex mode which conforms generally to the 
desired configuration of the external surface 13 of the breast. As will be 
obvious, the size and shape of the prosthesis will be varied in accordance 
with the requirements of the patient. 
The interior of the prosthesis 10 is divided into a series of chambers 14, 
15, 16, 17, 18 and 19 in the illustrative embodiment, it being understood 
that as few as two chambers may be provided and that 6 represents a 
probable maximum. 
Chambers 14 through 19 are defined by transversely directed fabric dividers 
14' through 18' the dividers being less stretchable than fabric 11. The 
chambers 14 through 19 contain filler fibers as more fully described 
hereinafter, the fiber density within the chambers increasing 
progressively from the anterior most chamber 14 to the posterior most 
chamber 19, the fibers F as depicted in FIG. 1 being schematically 
illustrated as disposed in parallel to illustrate the variations in 
concentration, it being understood that in the actual structure the fiber 
bundles are preferably randomly oriented. 
The divider fabrics 14' through 18' are comprised of pervious material, 
both to body fluids and to fibrous tissue growth. The external fabric 12 
is likewise pervious to fluid and tissue growth, the fabric 12 preferably 
including a velour like or looped external surface. 
To this end, there is disclosed in FIG. 2 by way of representative example, 
a plan view of a tricot knit fabric 12 a running line of loops or stitches 
of the knit being stippled to emphasize the broad loops 20 defined on the 
outer surface of the knit as an inherent element thereof.degree. While a 
tricot knit has been illustrated, satisfactory results may likewise be 
obtained by the use of a Raschel knit, the important characteristics of 
the fabric 12 being relative stretchability and the existence of velour 
like external loops. 
While knitted-stretchable fabrics are preferred, it is feasible to employ 
certain woven fabrics such as those disclosed in U.S. Pat. No. 4,892,539 
issuing to one of the inventors named herein, as well as U.S. Pat. No. 
4,517,687, both of said patents being herein incorporated by reference. 
It is to be understood that the fabrics of the cited patent references are 
employed herein in a totally different environment than that called for by 
the patents, and specifically are intended to be pervious to fluids and 
tissue in-growth in the instant environment, whereas in the environment 
described in the patents (vascular grafts) tubular increments of the 
fabrics are rendered impervious by infusion with the blood of the patient 
which is coagulated on the interior surfaces. While the woven fabric of 
the patent references is structurally acceptable, the woven fabrics 
thereof have the disadvantage of limited stretchability with the result 
that fold lines or creases in the prosthesis may not be avoidable. 
Best Mode Disclosure 
In keeping with the requirements of the Patent Laws there is described 
herein below the best mode currently known to applicants in respect of the 
characteristics of fabric and filler for the implant. 
It is to be understood that the materials are described by way of example 
and not by way of limitation, and that it is anticipated that other 
materials, both known and hereafter created, would function adequately in 
the environment of the prosthetic device. 
A preferred yarn for fabricating the exterior 12 is a homopolymer polyester 
with minimal additives or contaminants. Suitable fibers are manufactured 
by the Dupont Corporation and identified as DACRON TYPE 56T and by WELLMAN 
INC. under the trademark FORTREL (TYPE 302). The fibers used in the 
formation of the knitted shell 12 are preferably comprised of a 50 denier 
multi-filament textured dacron type 56, the yarn being comprised of 47 
filament fibers making up the bundle. 
The filaments making up the yarn of the preferred example are 1.06 denier 
filament diameter, successful results being anticipated with fibers in the 
range of 0.4 to 3 denier. 
Knitting is effected to provide a fabric having a weight of 1.5 to 6 ounces 
per square yard, 21/2 ounces per square yard being considered optimal. The 
knitting of the yarns within the noted weight ranges provides a liquid 
permeability of the resultant fabric from a minimum of about 50 
cc/cmsq./min. at a standard of 120 mm of mercury pressure for the least 
densely woven material to approximately 10,000 cc/cmsq./min. for the 
minimum density material. 
A preferred permeability value for the fabric 12 is approximately 2000 
cc/cmsq./min. The internal layers 14' through 18' are preferably of high 
permeability, i.e. greater than 2000 cc/cmsq./min. The internal layers 14' 
through 18' are preferably, but not necessarily, woven. The use of the 
stretchable or distensible external fabric 12 in combination with the 
woven and hence more shape retaining internal dividers provides a unique 
structure which is enabled to expand and contract with minimal distortion 
in a radial direction. 
The polyester polymer yarns used for the various fabrics may be textured or 
untextured, textured being preferred since it enhances tissue in-growth. 
With respect to the fiber employed in filling chambers 14 through 19 the 
Wellman Type 302 is preferred. The denier of the fiber filaments may vary 
from anywhere between 0.4 denier to about 3.5 denier. A preferred value 
comprises fiber chopped into lengths of about 11/2 inches with a weight of 
2.25 denier. Fiber lengths may range from 1/2 inch to over 4 inches with 
shorter fibers used in the anterior located chambers. 
With respect to the density of fiber fills, the fiber density will increase 
in the posteriorly located chambers to as much as approximately 0.36 grams 
per cubic centimeter of polyester staple fiber. Fiber density in the 
anterior most chamber may be as small as 0.01 grams per cubic centimeter. 
The densities noted are calculated based on the preferred 2.25 denier, 
11/2 inch lengths fibrous materials. 
From the foregoing, it will be appreciated that there is provided in 
accordance with the invention a new and improved breast prosthesis which 
is permanent, and which, after implant, accurately replicates the natural 
human breast in all aspects. When constructed of the preferred somewhat 
stretchable fabric, due to the distensibility of the device, and the 
encouraged in-growth of body tissue and fluids, a degree of volumetric 
distention and contraction of the prosthesis as well as limited contour 
variation is possible to coordinate the size of the prosthesis with weight 
gain or loss by the patient. In contrast with known prosthesis where the 
size of the device controls the shape of the body, in the instant device 
the body controls the size of the prosthesis. 
It is important to note that each of the chambers defined by the interior 
partitions provides an environment for the in-growth of body tissue, the 
amount of tissue in-growth and fluid retention being controlled in 
accordance with the density of fiber fill within the respective 
partitioned chambers. By providing chambers having different fiber 
densities in combination with a highly permeable retaining structure there 
is created for the first time a prosthetic breast implant which may be 
tailored to the specific requirements of the patient to enable desired 
cosmetic and tactile end results. 
Since the interior of the prosthesis will ultimately be permeated with 
living tissue, the implant will be retained essentially at body 
temperature and the thermally induced discomfort inhering in the use of 
liquid filled devices avoided. 
As will be apparent to those skilled in the art and familiarized with the 
instant disclosure numerous variations in details of construction and 
selection of materials may be made without departing from the spirit of 
the invention. Accordingly the invention is to be broadly construed within 
the scope the appended claims.