Even a short essay on implant overfill can be confusing, because it is a complex 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.
First, lets clear up some confusion. Overfill is not the volume added over and above the manufacturer's minimum volume or the implants base volume. Overfill is the volume added to an implant that is more than the manufacturer's MAXIMUM limit. Who says so? The manufacturer. If you read the implant brochures carefully you will find this sentence: "Follow the recommendation on the product data sheet for fill volume; do not overfill or underfill the implant." The recommendation on the product data sheet for fill volume gives a minimum (eg 400cc) and a maximum (eg 425 cc) for every implant, and thus the authorized range is 400-425. The manufacturer would not tell surgeons to not fill to 425! Their only concern is that the surgeon not Underfill (less than 400) and not Overfill (more than 425). Therefore, overfill means to exceed the manufacturer's MAXIMUM permitted volume. Those who maintain otherwise are not reading the brochures correctly.
Every implant has an Optimal 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). The difference between inadequate volume and the Optimal volume is astonishingly small, around 10%, which may be only a couple tablespoons of water! It is quite remarkable that such a small amount of added water can make such a big difference. Women who are troubled with wrinkling because their implants were not filled to the ideal Optimal volume may need an operation to add that critical tablespoonful of saltwater that makes all the difference. It is amazing what a difference such a small amount can make. OK, it seems obvious and simple so far, right, just fill the implants to the Optimal volume every time so you don't have to re-operate; so what's the problem?
The problem is that for most implants, the manufacturers have registered the maximum volumes too low with the FDA, below the Optimal. 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 Optimal, it will be beyond the manufacturer's registered maximum, that is "overfilled". So for those implants, the majority of surgeons will overfill, that is, fill to the Optimal for minimum wrinkling, even though the manufacturer's maximum is exceeded.
So what's the big deal here, the manufacturers should 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 Optimal, 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 Optimal levels.
Can overfill to decrease wrinkling shorten implant lifespan? Actually, it is the opposite: bringing the implant to its Optimal helps the implants last longer, even though that may exceed the manufacturer's maximum. Why? Because wrinkling leads to premature failure by causing high stresses at the folds and wrinkles. Studies have shown that Optimal filling, by reducing the wrinkling, actually helps the implant last longer. [For those who prefer to actually look up the studies proving this, here are the citations: Lantieri, L. A., Roudot-Thoraval, F., Colins, E.D., et al. "Influence of underfilling on breast implant deflation." Plastic Reconstr. Surg. 100: 1740, 1997. Lavine, D.M. "Saline inflatable prostheses: 14 year's experience." Aesthetic Plast. Surg. 17:325, 1993. Mladick, R.A. "Inflatable breast implants". Plast. reconstr. Surg. 95:600, 1995. Raj, J., and Wojtanowski, M.H. "Spontaneous deflation in saline solution-filled breast implants." Aesthetic Surg. J. 19: 24, 1999.]
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, even though the shell was exactly the same as the other registered-too-low implants. So why not use only those correctly registered types? Because they are not available in all sizes and shapes! Does it seem to you that somewhere along the way, bureaucracy has made things a bit more complex than they need to be? Then you are understanding the overfill issue.
Why doesn't overfill change your size? Overfill only concerns the relationship between the volume of saline and the implant itself, and has 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?
Let's look at this another way. Let's say you know what volume it is going to take to bring you to the size you want to be. For example, let's say that you and your surgeon have completed your sizing, and determined that it will require 390 cc's (13 ounces) to do so. Now, what are some options available, all ending up with 390 cc's? Here are some different ways to do it:
A.WITH IMPLANTS FILLED TO THE Optimal:
(Lasts longer, least rippling, but somewhat firmer and rounder)
1.No overfill needed to get to Optimal:
a.McGhan 468 #27-468381 "380" 380-400 (390 is not overfill)
b.Mentor 1400 #350-1450 "325" 325-390 (390 is not overfill)
2.Getting to Optimal requires overfill
a.Mentor 1600 #350-1650 "325" 325-375 (390 is overfill)
b.McGhan 68 #25-68331 "330" 330-360 (390 is overfill)
B.WITH IMPLANTS FILLED BELOW THE Optimal:
1.Sub-Optimal, but still within manufacturers range:
(fair durability, more rippled, softer)
a.Mentor 1600 #350-1655 "350" 350-400 (390 is sub-Optimal)
b.McGhan 68 #25-68361 "360" 360-390 (390 is sub-Optimal)
c.Mentor 1400 #350-1460 "375" 375-450 (390 is sub-Optimal)
2.Underfilled:
(poor durability, very rippled, but very soft)
a.McGhan 468 #27-468451 "450" 450-475 (390 is underfilled)
b.Mentor 1600 #350-1670 "425" 425-475 (390 is underfilled)
c.McGhan 68 #25-68421 "420" 420-450 (390 is underfilled)
d.Mentor 1400 #350-1470 "425" 425-510 (390 is underfilled)
Again, note that some implants do not require overfill to reach the Optimal volume, particularly those registered with the FDA in recent years. Why not? Simply because the manufacturers did better calculations and registered them for volume ranges that included the Optimal. In my opinion, these implant styles need overfill to get to the Optimal volume: McGhan 68 and 168, Mentor 1600 and 2600. And likewise, in my opinion, these do not: McGhan 468, Mentor 1400, 2400, 2700. So why not always use only these implants? Because they are not available in all sizes and styles.
Some plastic surgeons intentionally underfill the implants. They do so because underfilled implants are softer feeling. They understand that the implants wiill not last as long, but in their opinion softness is more important than durability. They also understand that there will be excessive upper pole collapse and wrinkling at the top of the implant, which in turn means that they are limited to putting the implants under the muscle. Looked at another way, that means that surgeons who do not adequately fill implants, will have to put them under the muscle (and will have to replace them more often) to decrease visible upper breast rippling. On the other hand, surgeons who fill implants to the Optimal are free to place the implants either over or under the muscle, with no difference in rippling.
Remember, surprising as it may seem, although not changing the size much at all, even half an ounce (3 teaspoons) makes a significant difference in terms of wrinkling of some implants. This is all fairly complex, and must be individualized for each patient, so please discuss this all with your surgeon.
Keywords: Breast implants through the navel; Transumbilical breast implants; Belly-button breast implants; Through-the-navel breast enlargement; Through-the-navel breast augmentation; Trans-umbilical breast augmentation; Trans-umbilical breast enlargement; Belly-button breast enlargement; Belly-button breast augmentation; Breast enlargement through the navel; Breast augmentation through the navel; Navel breast enlargement; Navel breast augmentation; 'Scarless' breast enlargement; 'Scarless' breast augmentation.