This is an excellent question, and at least for the US market, it has only been pertinent for less than a year because Allergan just released the SoftTouch implant less than a year ago. It has been available in Europe for much longer, it's just that the FDA approval only came through in January 2017 for the US. Prior to that, Allergan only had their Inspira Response gel (the older 4th generation cohesive gel) and the Inspira Cohesive implant, which was a highly cohesive gel ("gummy bear") implant, but noticeably firmer than both Sientra's and the new SoftTouch. All of the Sientra implants have always been the "gummy bear" variety, and to date they have been the softest yet strongest of all on the US market. The SoftTouch addressed this issue by coming out with a beautifully soft highly cohesive ("gummy bear") gel implant that has all of the properties of the other "gummy bears" but is very soft. Your question really gets down in the weeds as far as the detailed differences between the implants goes, and in cases like this, we have to figure out which differences are the biggest, which are the most clinically significant, and which implant's most important properties suit us the best. Notice I didn't say perfect; just the best overall. There is no perfect implant. We will always be trading off one thing or another when we are deciding on breast implants. This is precisely why I have made it a habit in my own practice to be familiar with all 3 manufacturers in the US and to use all of the types of implants that are available - sometimes one particular implant works best for one person, while an entirely different one works best for another. As along as you are comparing apples to apples - that is, highly cohesive, or "gummy bear" gel implants to the same - performance data are very, very close, and many times the issue of choice boils down to one or two very specific features or offerings, and we just accept that things like rupture rates will be very, very close, if not exactly the same. What I mean is this: you have already pointed out one of the biggest differences in the Allergan Inspira line already, and it has nothing to do with rupture rate. The Inspira implants have a slightly higher gel fill ratio, meaning, yes, they are filled slightly more. This is not that important in some ladies, while in others it may well be. The big advantage of this is that a slightly higher fill ratio will make the implant much less likely to ripple and fold, and in ladies with thinner tissues, this could be very significant because they will feel their implants a lot less. Inspira has always been a bit more overfilled, that's the brand identity within the Natrelle line by Allergan that makes Inspira Inspira - Inspira is an overfilled gel implant. The game changer was when the SoftTouch was introduced. It's a beautiful implant, and it now competes directly with Sientra. I love Sientra. I love the company, I love their implants, and I use a lot of them. But, if I'm being honest, I will say that there is merit to the SoftTouch when compared to Sientra's round implants for that reason. I have used a lot of SoftTouch implants now too, and in the thinner girls who want a bit of projection, they work beautifully. Can I say that the rupture rates are identical? Are the gel fracture rates and gel-shell relationships the same? Probably not according to the laboratory and engineering data, but when we're looking at our list of priorities when selecting implants for a specific patient in the clinical setting, the aesthetics and propensity to ripple and be palpable may be more significant to that patient than the infinitesimally small difference in rupture rates. Nobody wants to go back to the OR more than they need to, but we have to balance the statistical chances of that with our other goals too. Another issue that I have found between the two implants is that Sientra right now is a bit more limited with size and dimension choices. I hate to say this, because again, I love Sientra as a company and what they've done for the American breast implant scene in general, but the reality right now is that they are still a young company and not the behemoth that Allergan is, so their manufacturing capabilities are still in a growth phase. Because of that, they may lack some of the selection in certain sizes and profile dimensions that Allergan can offer right now. This won't last long, as they are building momentum, but for now, I have to say that sometimes I select an Allergan implant for a patient due mostly because of size/dimension considerations and availability.So, in summary, I applaud you for your discriminating taste and your drive to do the important research - you've happened upon two excellent implants with very comparable track records and very comparable performance. But there are some subtle, and maybe for you significant, differences between them, and it pays to understand what those are. Armed with your research, have another discussion with your surgeon, or maybe even get an additional opinion, hopefully from someone with real world experience with both types of implants, so that you can get a detailed analysis of your specific goals and needs and pick the best implant for YOU. Best of luck!
