Patients have been asking me about the new brand of breast implants that was recently approved by the FDA and is now available for use in this country. The implants are manufactured by Sientra, a Brazilian-based company, and come with both saline and silicone fill, both smooth and textured surfaces, and in the round or anatomical shapes. Although the implants are new to the United States, clinical trials to establish their safety have been conducted over the past several years.
The most important advantage to these new implants is that they are available with a “form stable” silicone gel. The “non-form stable” gel implants are widely used in the United States today and include the MemoryGel Mentor Implants that I use in my practice. The MemoryGel is thicker than the gel used in previous generations of breast implants, but the gel used in the new Sientra “form stable” implants is even thicker, giving the implant the nickname of the “Gummy Bear Implant” because it feels a bit like the candy well known to many of us and our waistlines! These form stable implants are widely used throughout the rest of the world, but have not been commercially available in the United States until the introduction of the Sientra implants earlier this month.
What are the theoretical ADVANTAGES to this form stable implant offered by Sientra?
• Shape – “Non-form stable” fillers such as saline and standard silicone gel will change shape according to the forces placed upon them by the breast when they are inserted for breast augmentation. In contrast, form stable fillers will maintain their shape and in so doing, change the visible shape of the breast.
• Folds and Rippling – An implant consists of FILLER such as silicone or saline that is contained within an elastic, rubbery, clear cover called a SHELL. Since the thicker, form stable gel doesn’t shift around inside the shell like regular silicone gel, we don’t see the type of folding and collapsing of the implant shell that occurs with the older style of implants. This makes for less rippling that can be seen or felt with this newer type of implant.
• Decreased Leakage – As just explained, these newer implants don’t seem to fold as much owing to the form stable gel. Since most leaks are thought to arise from cracks in the shell that occur along folds in the implant shell, it would logically follow that one would expect to see a lower leakage rate in these form stable implants. This is what has been found in scientific studies, including one involving several thousand patients in Sweden. Even if the shell does crack, the “thick” nature of the form stable gel holds the gel together, making migration of the gel away from the implant and into the surrounding tissues less likely.
• Capsular Contracture – Some patients with breast implants will develop scar tissue contracture around their implants, producing a firm feel to the implant that may be uncomfortable and deforming. This occurs less often with the form stable implants according to studies performed in countries where these implants are used.
What are the theoretical DISADVANTAGES to these form stable implants?
• When a relatively stiff implant such as these form stable devices is placed within the breast, the implant may not contour to the shape of the underlying rib cage as well as do the traditional silicone implants. As a result, the edge of the implant may tend to lift up off the rib cage and produce an edge that can be felt or seen along the inner edge of the breast.
• Excessive Firmness – Because these are firmer implants, the breast may feel firmer with them in place. How firm will depend upon things such as how much breast tissue overlies the implant and how large of an implant has been used relative to the amount of breast tissue.
• Rotation – Textured implants are more apt to rotate than smooth implants because the body tends to produce a layer of fluid that surrounds the implant. If a shaped implant, also known as a “tear drop” implant, is being used, this rotation can produce an odd look. One can avoid this problem, however, by using round implants.
• Illness? – As I discussed in my February 2, 2011 blog (http://www.drsanders.com/blog/?p=13&replytocom=6321),
there is concern over the rare development of ALCL in certain women with breast implants. As studies go on, it would appear that virtually all of these women have textured implants in place. Furthermore, women with textured implants seem to be more prone to develop fluid around their implants that may require aspiration or even implant replacement.
As these form stable implants are used, more information will become available which will clarify the situation. I will be revisiting this topic in future blogs.
George Sanders, M.D.