consider 1 cup size to be about 150 mls or cc, if an implant is under the muscle you need to allow about 75-100 cc more.
Measure the base width of the breast mound as a linear measurement from the visible medial border of the breast mound to the visible lateral border of the breast mound in front view.
Nipple-to-inframammary fold distance (N:IMFMaxSt), measured under maximal stretch
For optimal long-term coverage, the base width of the implant selected should not exceed the base width of the patient's existing parenchyma, except in cases of tubular breasts, severely constricted lower pole breasts, or breasts with a base width less than 10.5 cm
IMF distance to nipple should be at least 7cm depending on implant size chosen
Deciding on Implant Type
1st generation (Dow Corning 1974-1978)
thick silicone rubber elastomer shell with seams and smooth surface
high-molecular-weight “gum” filled with amorphous silica
Rupture rates were low because of the tough shell,
complications from high capsular contracture rates and gel-filled seepage was probably considerable.
2nd generation (1979- 1987)
Smooth surface thin shells
Less viscous gels
Higher rupture and bleed rates
3rd generation (1980s)
increasing the thickness of the outer envelope
adding an inner barrier layer to limit silicone gel diffusion
using a thicker silicone gel material which is less likely to migrate into surrounding tissues should rupture occur.
reduce contracture (<3%) by causing an inflammatory reaction, microencapsulation of fragmented debris and surface irregularity leading to multidirectional contractile forces.
polyurethane coating started disintegrating so that what eventually remained was a mostly smooth implant surrounded by a capsule containing foam fragments.
Pain, fluid accumulation, and infection were reported.
Chronic foreign body reaction
Foam fragments made for difficult implant removal
Allergic reactions reported.
FDA reported in 1992 that breakdown foam (toluene diamine) products from in vivo hydrolysis may be carcinogenic - estimated lifetime cancer risk to a human from release of TDA from the cover of a breast implant is 41 per million per implant
Third generation shells have a barrier layer on the interior surface.
The reduced contracture rates of polyurethane foam was thought be to due in part to the texturing
Microtexturing the surface of an implant by ion-etching was found to modify the response of the surrounding soft tissues to the implant and retard the development of an organized, tight collagen capsule.
Picha confirmed that the collagen in the capsules around rough-textured implants was less organized and less dense than that of smooth surfaced implants.
From animal studies, a pore size of 350 μm was required to disrupt the formation of a continuous capsule aligned parallel to the implant surface
treatment of early capsular contracture by overinflation and subsequent deflation
mammographic examination of breast tissue is possible by deflating the implant
Disadvantages of the technique include the financial cost of the prosthesis, palpable axillary ports, and displacement or flipping
Saline and gel forms
tapered upper pole and fuller lower pole are designed to match the ideal breast shape, with the more fixed shape designed to prevent upper pole collapse under gravity ie gravitational forces dictate fluids conform to a teardrop shape.
given the same fill volume, an anatomic implant with its narrower base will produce greater projection (24.4%) and greater height (19.6%) than a round implant.
patients who desire more projection in the lower pole
patients who wish maximum size appearance per given volume
glandular ptotic breasts
constricted lower poles
breasts with highly mobile parenchyma likely to slide off the anterior surface of a round implant and produce the “double bubble” deformity
Round implants less appropriate for:
patients with a high inframammary crease
patients with a vertically or horizontally deficient chest
In breasts with a tight lower pole - maintain fullness in the lower pole against the constricting force of the tight skin envelope
patients with wide chest girths - narrower base diameter of the anatomic implant will not be sufficient to reach the anterior axillary line, and in this instance a round implant, having a wider base and more volume, may be more esthetic and achieve the same degree of projection
some textured implants experience no anchoring fibroblastic ingrowth or collagen deposition
a biofilm or meniscus likely surrounds breast implants, further discouraging fibroblastic ingrowth, and possibly acting as a lubricant;
the forces exerted on a retromuscular implant by the pectoralis major (even more so if the muscle is partially released) are directed in a horizontal and oblique vector (i.e., clavicle and midsternal origin to humeral greater tubercle insertion).
lower capsule formation than gel (10-40% vs 36-88%) and contracture rates (no silicone bleeding). Lower contracture rate independent of implant placement
Gylbert PRS 1990 – smooth gel vs smooth saline 50% vs 16% contracture
Texturing likely to reduce contractures further
easier to insert – can be deflated in situ
asymmetries easier to correct
medications can be added with saline
Average of 5 percent.
Factors affecting rate:
Age of implant
Type of implant
texturing (less deflation)
Unnatural feel – mobile, nonfixed
Propensity for surface irregularities and rippling
Less suitable in subglandular position
Silicone is the generic name for a family of silicon-carbon–based polymers.
regarded as one of the most compatible materials available for implanting into the human body
The polymer chains vary in length: the longer the chain, the greater the viscosity of the silicone.
Prone to seepage. The adverse reactions consisted of oxidation of the oil, foul smell, 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.
Decrease in volume over time
Rupture rate 10%
Lumpy capsular contracture
?carcinogenesis from breakdown products – recommended that all Trilucent implants be removed.
Transaxillary +/- endoscopic assisted
Hoehler 1973 – blunt blind subglandular dissection using urethral sound
Ideal for those with small breast volume in a high position on the chest
Can also be placed subfascial and retropectoral
Endoscope assisted popularized by Tebbets
Early concerns over limited visibility for dissection, implant malposition, and insecure hemostasis have faded with mounting experience.
Use of endoscope has facilitated release of the inferior musculofascial attachments
Advantage of this technique is that the scar is small and not noticeable and no incision on the areolar, breast skin or parenchyma