FAQs: Breast Implant Overfill – Breast Augmentation

Overfill of Breast Implants? Please fill me in.

Even a short course on implant overfill can be confusing, because it is a confusing issue. If you are ready for a confusing ride through the bureaucratic maze, here goes. First, an important fact: overfill does NOT mean you will look larger, and does not mean making the breast larger than what you wanted. It means putting the volume of saline that it has been determined you need, into an implant with a maximum rating for a slightly smaller volume. That is another way of saying that overfill means filling an implant to more than the manufacturer's maximum recommended level, period. Why would anyone exceed the manufacturer's maximum recommended level? Read on.

Every implant has an optimum volume of saline fill, a volume that gives the best balance between either wrinkling (caused by not enough saline) or too firm/round (caused by too much saline). Seems obvious and simple so far, just fill the implants to the optimum volume; so what's the problem? The problem is that for most implants, the manufacturers registered the maximum volumes too low with the FDA, below the optimum. So if your surgeon stays within the manufacturer's recommended range for these implants, they will wrinkle noticeably, and if the implant is filled to the optimum, it will be beyond the manufacturer's registered maximum, that is "overfilled".

So for most implants, the majority of surgeons will overfill, that is, fill to the optimum for minimum wrinkling, even though the manufacturer's maximum is exceeded. So what's the big deal here, just go to the FDA and tell them to change the numbers on their records to reflect the real world usage of implants to give the patients the optimum, right? Wrong. The manufacturers did approach the FDA to get the registered volume numbers changed, but were told they would have to spend millions of dollars before the FDA would change those volume numbers in their paperwork. OK, then the manufacturers just should tell the surgeons to go ahead and exceed their maximums to decrease the wrinkling, right? Wrong. The FDA will not permit the manufacturers to actually authorize this overfilling to optimum levels.

Can overfill to decrease wrinkling shorten implant lifespan? Nobody knows the answer to that yet, but a growing number of plastic surgeons are of the opinion that optimal fill to decrease wrinkling may actually help implants last longer. Why? Because we do know, without a doubt, that severe wrinkling leads to premature failure by causing high stresses at the folds and wrinkles. It may well be then that optimal filling, reducing the wrinkling, may actually help the implant, but we do not know for sure. One other indication that overfill may be perfectly safe for implants is that some of the more recent models of implant have been given higher fill volume ranges when they were registered. So why not use only those types? Because they are not available in all sizes and shapes.

Why doesn't overfill change your size? Overfill only concerns the relationship between the volume of saline and the implant itself, and nothing to do with the relationship between the volume of saline and your breast. Because the correct saline volume for you should have been accurately determined by your plastic surgeon in advance (one hopes), then only after that the implant itself is selected for that volume to be optimal. Those are the medical decisions; then, the surgeon will check to see whether that optimal volume is greater than the manufacturer's FDA-registered maximum, and if so, you need "overfill".

Here's an example: let's say you have demonstrated to your plastic surgeon the size you want to be, and as a result, he/she has determined that you need 330 cc's to achieve that proportion and bra size. That is the first decision. Next comes the decision of which implant to put that volume into. Theoretically, it could go into just about any implant, so for discussion let's look at implants rated for these ranges:

210-240, 240-270, 270-300, 300-330, 330-360, and 360-390

What would happen, assuming that these are all the style of implant that was FDA-registered with a sub-optimal volume?

  • 330 in a 210-240: 38% overfill = no wrinkling, but very round and hard
  • 330 in a 240-270: 22% overfill = not much wrinkling, but too round and too firm.
  • 330 in a 270-300: 10% overfill = optimal compromise between soft feel and minimal wrinkling
  • 330 in a 300-330: FDA maximum = soft, but suboptimal due to wrinkling
  • 330 in a 330-360: FDA minimum = very wrinkled, unacceptable
  • 330 in a 360-390: underfill = extremely wrinkled, and implant will fail prematurely

Again, note that some implants, particularly those registered with the FDA in recent years, do not require overfill to reach the optimum volume. Why not? Simply because the manufacturers did better calculations and registered them for volume ranges that included the optimum. So why not always use these implants only? Because they are not available in all sizes and styles. This is all fairly complex, and must be individualized for each patient, so please discuss this all with your surgeon.

This FAQ contributed by Richard V. Dowden, M.D.

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