7 THINGS YOU SHOULD KNOW ABOUT SILICONE IMPLANTS & BREAST AUGMENTATION SURGERY
1. How long have breast implants been around for?
Breast augmentation is the most popular aesthetic surgery procedure. Despite or perhaps because of this, it has had a chequered history in comparison to other major aesthetic procedures. The vast amount of space and literature devoted to the subject is a testament not only of its pre-eminence to the field, but also arrays of differing opinions and philosophies. This is perhaps chiefly due to the use of prosthetic devices and intermittent controversy regarding their safety. Czerny reported the first breast augmentation when he transferred a lipoma from a patient’s back to the breast. Over the years many injectable as well as implantable materials have been used including shellac, beeswax, epoxy resin, petroleum jelly, Teflon, polyurethane and polyvinyl alcohol to name a just a few. In 1961 injectable silicone was reported by Uchida. The introduction of silicone breast gel implants by Cronin and Gerow in 1962 revolutionised breast augmentation surgery.
2. What is Silicone and Why is it Used for Breast Implants
Silicone, or dimethylpolysiloxane was first developed during WWII as part of aircraft engineering. Its softness and inert nature made it the perfect prosthetic substrate for medicine. Silicone breast implants can be divided into five generations based on the shell thickness, texture and implant fill. The other major clinically applicable implants are saline implants. Alternative breast implants have been developed over the years including Polyvinylpyrrolide, triglyceride and hydrogel, none have withstood the test of time. Current implants available on the market are variations on the same theme, divided by gel fill into saline and silicone when used in augmentation procedures.
3. How have implants evolved within breast augmentation since inception in 1962?
The first generation implants manufactured by Dow Croning were composed of viscous silicone gel contained in a thick tear dropped shell. Seams and Dacron patch present on the periphery and posteriorly respectively were thought to help stabalise the implant in position. The high early capsular contracture rates resulted in an evolutionary step towards a second generation of softer implants; smooth, seamless and containing less viscous silicone in the mid to late 1970s. Whilst this reduced the capsular contracture rates in augmentation procedures somewhat, they were associated with a phenomenon known as gel bleed related to small molecular weight particles of silicone diffusing across the thin silicone elastomer shells. This in turn has been implicated in the pathogenesis of capsular contracture. Recognition of this led manufacturers to develop a third generation of implants with a strengthened silicone shell. Two layers of high-performance elastomer formed the shell with a fluorosilicone coating barrier between them. The fourth generation of textured implants was developed partly in response to emulating polyurethane foam’s natural pores.
Polyurethane foam applied as a thin layer in the 1970s onto the implant shells resulted in very low capsular contracture rates in augmentation procedures. The process of delamination of the foam from the implant resulted in a non-contractile capsule, yielding immobile yet the soft feel. They were withdrawn in 1990 after concerns were raised about the carcinogenic nature of the polyurethane by-products. Yet, the good clinical outcomes led to development of two forms of pores by American manufacturers. Biocell developed by McGhan Medical and Siltex developed by Mentor. Biocell is composed of an irregular open pore textured surface with an average density of 3.1 pores/mm2 and an average pore size of 289 microns. These pores created by a lost salt technique develop capsule through an adhesive effect. Although this is similar to polyurethane there is no delamination. This shell characteristic has been used for both saline as well as silicone filled implants resulting in immobile yet soft implant feel and lower contracture rates. Siltex however, is a textured surface characterised by pattern of nodules ranging in height (65-150 microns) as well as width (60-275 microns). These do not adhere to the surrounding tissues, consequently they are mobile in the pocket and have resulted in lower contracture rates whether saline or silicone filled.
The fifth generation of silicone implants are textured implants with form stable silicone. This is achieved by increasing the cross linkage of the silicone gel. This allows maintaining their shape in all positions. The only one of the dual chamber implants that remain on the market are the Becker inflatable implants.
4. Why is this texture business important?
Late fluid collection (Seroma) around textured implants may be associated with Anaplastic Large T Cell Lymphoma (ALCL), the treatment option is referral to the breast and haematology/oncology teams. Removal of the implant and capsulectomy is part of the treatment regime. This is now a well recognised complication of textured implants particularly the so called macrotextured implants.
5. How are Implants placed?
There are theoretically multiple access points:
- Around the nipple through the breast ( Peri-areolar incision)
- Under the breast ( Sub mammary incision IMF)
- Through the armpit (Transaxillary)
- Through the umbilicus (Transumbilical)
By far and away and for good surgical reason the best option for access in breast augmentation is the IMF access, reflected in recent survey from plastic surgeons.
6. Where are the implants placed in the breast?
There are 3 possible pockets for the implants:
- Under the breast tissues and over the muscle
- Under the muscle
- Partially under the muscle and partially under the breast tissue (Dual plane)
By far and away a well executed dual technique should give the best and longest lasting outcome.
7. How long does the breast augmentation operation take?
It depends but once the markings are done and the patient is asleep the surgery can take as little as 45 minutes skin to skin or as long as 90 minutes. Usually I tell my patients it will take 60 minutes.