Why is the largest size of Sientra round base shaped implant only a 425 cc?

Let me begin by saying that I am a big fan of the Sientra, shaped, round base implants.   The size limitations that exist are not due to Sientra but rather to the FDA's approval of breast implants.   When the breast implant manufacturers present their data to the FDA for approval, for reasons that are poorly understood by plastic surgeons, the FDA only approves a small selection of the available implants.  The implant manufacturers are continuing to work with the FDA to have more implant size and shape options available.

As Sientra is the newest Silicone implant United States Company they most likely went with the most popular sizes and the most varied shapes available. With time they will likely increase volume sizes

Maximum size of Sientra implantsThese were the first fda approved shaped implants in the US.  its just very difficult to get through the approval practice.  They will be increasing the spectrum of sizes in the future.

Sientra makes great implants and was the first implant manufacturer in the USA to obtain FDA approval for their shaped cohesive silicone gel implants. They also sell their products only to American Board of Plastic Surgery-certified plastic surgeons in the USA, whereas the other two implant manufacturers will sell their implants to any licensed physician who wishes to perform breast augmentation, regardless of specialty training. AND, Sientra offers a 2-year capsular contracture "warranty." This is not a "new" company, as they have been manufacturing and selling implants worldwide for many years, and were the first company to be allowed to sell implants in the USA since the FDA restrictions of 1992 caused all but Mentor and McGhan (now Allergan) to go bankrupt or cease selling implants. So certainly a solid choice for implants, as are the other two companies' products.But, I question your central premise that a "natural" look is achieved by a shaped implant more commonly or better than by a smooth round cohesive gel implant by Sientra or either of the other two implant manufacturers.
Since teardrop-shaped implants must have proper
positioning and must stay in that position (sloped part up, rounded part
down) to take advantage of their innate "natural" shape, by necessity they are
textured so that the body's tissues can adhere to and maintain the
proper position of the implants. Thus, teardrop implants
cannot and do not move very much at all as the patient changes from a standing to a
reclining position. Also, the teardrop implant remains teardrop-shaped
when the patient is lying down, whereas the natural breast flattens out
and assumes a round appearance. Shaped (form-stable) implants are
also more costly than round smooth implants. The smooth round implant
does just what a natural breast does: it is teardrop-shaped when the
patient is upright, and flattens and drops slightly to the side when the
patient reclines. Thus, the round implant is actually more "anatomic" than the teardrop, “gummy-bear,” or so-called anatomic implant.Some plastic surgeons believe that the “anatomic” or teardrop-shaped implant has a
more natural look than the round implant, and much advertising and
marketing has been used to promote “anatomic” implants to the public.
These implants are perfectly good devices, but they are more expensive than
the smooth, round implant, and whether or not it is truly more
"anatomic" is questionable, and has actually been studied. In this study, actual
women with smooth, round implants were compared to women with textured,
teardrop-shaped implants. Mammograms were performed in upright and
supine (lying-down) positions, and digital tracings computerized and
compared. Both the round and teardrop-shaped implants had a sloped,
teardrop shape when the women were upright. In fact, in upright
patients, teardrop and round implants were indistinguishable on X-ray, because the soft, cohesive silicone gel round smooth implants became teardrop shaped themselves.
But, when a woman is lying down, the natural non-augmented breast
flattens, drops slightly to the side of the chest, and assumes a round shape, as
does the round smooth implant. The teardrop-shaped implant stays
teardrop-shaped and does not move at all to the side in the lying-down position, which makes this actually LESS anatomic than the round implant! I just thought you should know that before you are "sold" a (usually) higher-cost pair of implants for reasons that are not necessarily valid. Best wishes! Dr. Tholen

Yes, Sientra's upper limit on volume for shaped high strength silicone implants maxes out at 425ccs - they have said larger implant volumes will become available. However, the projection of a round based shaped implants ( the one's giving more projection)  equals that of a round implant of a high profile projection of 600ccs or a moderate plus profile round implant of appx 800ccs. Remember that the projection and volume is centered in the lower aspect of the breast where it is supposed to be, instead of using extra volume creating a more rounded shape and fuller upper pole of the breast. You get more implant projection and shape of the breast with lesser volume of ccs that creates more and better shaped breast from the overall implant volume placed in compared to round shaped implants.

Shaped implants are not as large as the normal round implants. This is because if you look at the cross section of the shaped implant for a given base width diameter you are losing volume in the area of less projection. You always have to compare implants of the same base width.

Hi Nanzar,Sientra was the first company to get shaped gel implant approval. Even now,
they have the most shaped implant styles (5). Unfortunately, the FDA only
approved a limited amount of sizes for Sientra in their original application for
sizes. A matter of fact, they had larger sizes of that style and others in their
study. Sientra under the umbrella company Silimed, has made safe implants that have been distributed widely all over the world for many, many years. I checked with the company and they have since petitioned the FDA for approval of those larger
sizes in all styles.    One never knows with the FDA process how long this approval will take, but you can be assured it is in the works.  All the best, "Dr. Joe".

Thank you for your question.  I have been assured by Sientra that larger sizes are coming.  It is a matter of waiting for FDA approval.  I know, it doesn't make sense, all their implants are made of the same material so why can't the FDA just let them release other sizes and shapes as they become available.  Well, the FDA is the same organization that prevented us from using silicone gel for 15 years while it was perfectly OK to use in the rest of the world. They have also said it is OK for a woman to vote, drink, or go to Afghanistan and get killed or maimed but she cannot get silicone gel until she is 22. (There are exceptions) Go figure.  Your tax dollars at work!

Sientra is a new company in the United States within the last 3 years, which is quite a feat in the United States considering how strict the FDA is on breast implants. After the moratorium on silicone breast implants instated in the 1990s, only two companies, Allergan and Mentor, were able to do the studies required to bring silicone gel breast implants back on the market in 2006. These were only round silicone gel implants - smooth and textured surfaces with low, moderate, and high projections. Since that time, both companies added extra-high profile implants to the options. Roughly three years ago Seintra completed studies on both round and anatomically shaped implants and was approved by the FDA to bring new options to women for breast augmentation in the United States. Sientra was the first company to offer FDA approved anatomically shaped implants in the United States and they have 3 styles, one of which has a low, medium and high profiles. Shortly after that, Allergan and later Mentor gained FDA approval for their anatomically shaped implants. Allergan has two styles each with a low and moderate projection, and Mentor has one style. All of the companies would like to have more options with their anatomically shaped implants. Mentor could use more style options, Allergan could use an option with high projection, and Sientra could use larger sizes . . . and all of this requires studies and a rigorous FDA approval process that takes a significant amount of time and resources. All companies are working to bring more options to patients.I am a clinical trial investigator for breast implants for both Allergan and Sientra. I know that Allergan is currently looking to gain FDA approval for their anatomically shaped implants with high projection. I also know that Sientra is looking to gain FDA approval for their anatomically shaped implants with larger sizes.The implant you chose, the Sientra round base anatomically shaped implant is a unique implant. It is the only FDA approved anatomically shaped implant with high projection which means that you get the most volume and projection for a given base diameter. The only way to get a similar implant from another company is to enroll in a clinical trial with Allergan or Mentor, but even the study implants don't have quite the balance of volume and projection that the Sientra round base has. This implant is a favorite amongst my patients because they love the fullness and projection in the middle and bottom of the breast, while maintaining a full but natural top of the breast. A round implant with similar dimensions doesn't give quite as much projection and the extra volume is all in the top of the breast giving it a rounder appearance on top.At only 5 weeks after surgery, I would give it a little more time before you make any final decisions, at least 3 months. If your implants are under the muscle, the muscle needs time to relax and accommodate and with relaxation comes a look of more fullness. If you love the shape of the implant you have, you can certainly wait to exchange them for larger ones when they are available. Another option you may consider is fat transfer. I offer this to my patents who love the shape of the Sientra round base implant but want more volume. Fat can be gently liposuctioned from another part of your body (preferably the love handle region or outer thigh region) and injected to the breast to give more volume over the implant and especially in the cleavage region.

Hello Nanzar, Yes, for the Sientra shaped implant with round base the largest size is 425 cc. This is a real limitation for these type implants most notably when when we use them for breast reconstruction for cancer patients. Other shaped implants Natrelle 410 and other shapes/styles (non-shaped round implants or oval implants) Sientra makes do come in larger sizes. However, as far as the width of the implant relative to the volume and projection the Sientra round base has a very good projection to width ratio unlike other implants which end up being much too wide for the breast base leading to the implant projecting into the armpit area. I do not know timing usually the FDA has to approve different size implants even though it is the same implant only larger and this sometimes takes months other times years. It took almost 10 years for the FDA to approve the form stable shaped implants the first time.