History of implants

Q3b Breast
Compare and contrast breast implants used over the last 20 years – advantages, limitations,
In 1963, Dow Corning Corporation introduced the first silicone-gel-filled implant. The earliest Dow shells
had a high-molecular-weight “gum” filled with amorphous silica, and the gel in the implant was platinum
These early implants had a thick shells and gels. The silicone rubber elastomer shell usually had seams and
smooth surface. The inside contained a firm silicone gel and fluids. Rupture rates were low because of the
tough shell, but complication from capsular contractures were common and gel-filled seepage was
probably considerable.
Some implants had internal dividers to keep the gel from sagging into the central part of the implants. Seal
patches were used to close up any holes or slits left by manufacturers or the valve entrance to an expander,
and are still used for manufacturing today’s seamless implants. By the late 1960’s, Dow’s shells had become
less thick and were seamless.
In 1968, Heyer Schulte Corporation became the first domestic manufacturer of saline filled implants. Early
saline implants were fragile and heavy, with audible “sloshing”, and there was very high deflation rates up
to 76%, probably because of the high temperature vulcanizing process used to “cure” or strengthen the
The original thick-shell models were replaced in the 1970’s and early 1980’s by implants with thin shells.
But these had a greater tendency’s to rupture and deflate. These “second generation” implants were
generally smooth surfaced and had high contracture and gel-fluid seepage rates. More flexible gels were
introduced by various companies from 1972-1975, and thinner elastomer shells were introduced staring in
1980s- third generation implants developed but 1st and 2nd generation implants still used.
Implants consist of outer shell and filler. Charateristics of each compared
Shell configuration shells
All implants use Silicone elastomer
Thick shells vs thin shells
1. More resistant to rupture (1st generation=3rd generation>2nd generation)
2. More prone to contracture
3. Less permeable
Coated shell
1) Outer coating - Polyurethane foam coating
Advantage: This coating was reported to reduce contracture by causing an
inflammatory reaction. This reaction discouraged formation of fibrous tissue
around the capsule.
Complications: But the polyurethane coating started disintegrating almost
immediately so that what eventually remained was a mostly smooth implant
surrounded by a capsule containing foam fragments.
Pain, fluid accumulation, and infection were reported.
Foam fragments made for difficult implant removal
Allergic reactions reported.
FDA reported in 1992 that breakdown foam products may be carcinogenic
2) Inner coating
Third generation shells have a barrier layer on the interior surface.
McGhan’s Intrashiel – diphenyl barrier layer sandwiched between 2 silicone
Dow Corning Silastic II – fluorosilicone.
Advantage said to cause less bleeding
Seamless vs seamed
1. More rupture resistant
Textured vs nontextured
1. Textured devised in 1988.
2. Less contracture (10% vs 60%). The theory of texturing was the growth of tissue into
the irregular spaces of the shell would retard capsular contracture. Most studies
support this.
a. Mechanisms
i. inflammation dampens fibroblast
ii. collagen laid in disorganized manner.
iii. Textured elastomer allows less bleeding
3. The presence of synovial-like metaplasia, a foreign body granulomatous reaction, and
foreign material significantly greater in the textured implants. Significance unknown
4. More likely to be palpable or ripple (more visible)
5. Textured implants significantly softer than those with smooth-surfaced silicone
Round vs Anatomical
1. Anatomical will produce more projection for given width and volume
2. Round is better for wide chests
3. Anatomical is better for tight lower pole or nulliparous
Single vs Double lumen
An attempt to provide the cosmetic benefits of gel in the inside cavity, while the outside
lumen contained saline and could be used for an expander or even for injection of
antibiotics or steroids. The saline lumen was also thought to control contracture and gel
and fluid seepage or rupture, but studies over the years have largely disproved such
local steroid infusion has now been generally abandoned because of major problems with
rippling, soft-tissue atrophy, and implant extrusion
Expandible vs nonexpandible
1. more prone to rupture
2. more easy to achieve symmetry
3. tissue expansion principles where deficient in soft tissue
1) Saline
a) lower capsule formation (10-40% vs 36-88%) and contracture rates (no silicone
bleeding). Lower contracture rate independent of implant placement
b) easier to insert – can be deflated in situ
c) asymmetries easier to correct
d) medications can be added with saline
a) Deflation
a) The reported historical incidence of deflation is highly variable, ranging
from 0 to 95 percent, with an average of 5 percent. More recent studies
cite an incidence around 1 percent. Factors affecting rate:
i. length of follow-up
ii. the year of implantation
iii. underfilling
iv. texturing (less deflation)
v. capsular contracture
b) Sloshing
c) Unnatural feel
d) More rippling
e) Less suitable in subglandular position
2) Silicone
a) Natural feel and look
a. Bleeding (higher contracture rate)
b. Poorer xray transmission
Recent larger studies of breast cancer following augmentation mammoplasty suggest breast cancer
diagnosis may be delayed in women with augmentation.
Brinton et al 2000 found women with breast implants (N = 78) tended to have later-stage disease
compared with women without augmentation (35% vs 17% with regional or distant disease);
however, this difference was not statistically significant.
Skinner et al 2001 found that mammography was less sensitive for women with augmentation (N
= 99) compared with women without augmentation (66.3% vs 94.6%) and that women with
augmentation were more likely to be diagnosed with palpable tumors (83% vs 59%), invasive
carcinoma (82% vs 72%), and to have nodal involvement (48% vs 36%).
Miglioretti et al 2004 - Among asymptomatic women, the sensitivity of screening mammography
based on the final assessment was lower in women with breast augmentation vs women without
(45.0% [95% confidence interval [CI], 29.3%-61.5%] vs 66.8% [95% CI, 60.4%-72.8%]; P =.008),
and specificity was slightly higher in women with augmentation (97.7% [95% CI, 97.4%-98.0%]
vs 96.7% [95% CI, 96.6%-96.7%]; P<.001). Among symptomatic women, both sensitivity and
specificity were lower for women with augmentation compared with women without but these
differences were not significant. Tumors were of similar stage, size, estrogen-receptor status, and
nodal status but tended to be lower grade (P =.052) for women with breast augmentation vs
Cohesive gel silicone vs conventional silicone
a) easier removal in the event of rupture
b) maintains shape
c) less likely to ripple or fold
d) does not leak
a) harder feel
b) expensive
c) larger incision
d) only comes in anatomical – more obvious deformity if rotates
e) gel fracture
2) Hydrogel
a) PIP - hydroxypropyl cellulose hydrogel gel
b) NovaGold, MistiGold - polyvinylpyrrolidone hydrogel
Developed 1994
a) Excreted by kidneys if leaked
b) Provides an excellent lubrication, which in turn reduces the mechanical stress on
the silicone shell = Reduced wrinkling/rupture
c) Good xray transmission
d) Due to the adhesive, sticky consistency of the gel filler = Natural feel
a) swelling due to cosmetic gradient
b) expensive
c) insufficient safety details – not approved by FDA
3) Soy Oil (Trilucent)
a) clearest xray transmission
Studies have shown that the soya oil can leak out and infiltrate tissues. The adverse
reactions consisted of inflammation and swelling, both of which subsided when the
implant was removed. Even though the removal of the implants alleviated the swelling
and/or inflammation, and there was no evidence that they caused long-term health
problems, the implants were withdrawn in 1999.