Implants can be inserted through the belly button, the armpit, the nipple/ areola and through the inframammary crease (the fold below the breast). The location of the scar should be based on several factors.
The first consideration is the safety of the technique. The belly button approach is known to have a high risk of complications. Because of this, the American Society of Plastic Surgeons does not even recognize it as a valid approach for breast augmentation. Another consideration is whether the approach can yield consistently good results. The armpit approach makes it very difficult to control the shape of the breast consistently. The reason is that working through the armpit prevents the surgeon from properly visualizing all aspects of the inside of the breast. Thus, a lot of the shaping of the breast has to be done blindly. Therefore, the results can be unpredictable. The surgeon may have a great result one time, and a poor result the next time.
One must also consider the potential side effects and complications from each approach. There have been many studies which show that inserting implants through the nipple/ areola can increase the risk of capsular contracture. Capsular contracture is a condition in which the scar tissue around the implant becomes very tight and hard. This causes the implant to be squeezed and the breast appearance to become deformed. The theory is that making the incision around the nipple and areola cuts into milk ducts which have bacteria in it. The bacteria then get transferred to the implant as it is inserted. Although only a few bacteria get on the implant, it is enough to cause inflammation around the implant which then leads to capsular contracture. Another possible side effect/ complication of inserting implants through a nipple/areola approach is the risk of numbness and/or inability to breast feed. Although these risks exist with any surgery on the breast, it may be slightly higher with the nipple/areolar approach.
The last consideration should be the cosmetic appearance of the scar. The nipple/areola scar heals very well. The scar is made in the border between the dark color of the areola and the lighter color of the breast skin. This camouflages the scar very well. However, it is important to understand that all scars, no matter how perfectly they are designed and heal, are always visible. Therefore, the scar on the nipple/ areola will always be slightly visible when the breasts are not covered. The scar in the inframammary fold is designed to fall in the crease that will be formed once the implants are inserted and have time to "drop" to their final position. Even women who do not have a fold or crease to begin with will have a fold or crease after augmentation. Therefore, this scar heals in a location that is never visible, even when nude, unless the woman lifts her breasts. Furthermore, the scar heals very well in this location and eventually becomes a very fine line.
For all of these reasons, the inframammary fold is the preferred method of inserting implants for top surgeons. Using the inframammary fold allows for more control over the breast shape, which leads to better and more predictably consistent results, with the least amount of risk and the best chance for a barely noticeable scar.
Click on the video to learn more about the various incision and scar