I currently have 700cc and 750cc implants. Should I get 550cc or 450cc for my revision? (Photo)

The correct volume for your breast revision depends on a number of different factors, including your chest width. Using an appropriately sized implant is important to avoid distorting the shape of the breast. Respecting they width (within reason) and then modifying the projection of the implant to further change implant volume is the best option.
Whether or not a 450 implant a good option for you partly depending on the width of this implant, as well as the width of your breast 'footprint".

You have been over augmented and the volume is much too great. I would recommend explantation and lift using The Bellesoma Method. The implants are removed, your breast tissue is reshaped creating upper pole fullness, elevated higher on the chest wall and more medial to increase your cleavage. Vertical scars are avoided, nipple sensation (in 95%) and the ability to breast feed are maintained if not injured during your previous surgery. Later, fat transfers can be performed if additional volume is desired.

Best Wishes,

Gary Horndeski, M.D.

For breast implant size, there is a rough estimate of 150cc per cup size. If one wants to go down at least 2 cups sizes (300cc less), 450cc may be the better option. Narrowing the breast will help with a more proportionate look; besides smaller implants this could also be done with a breast lift and narrower base diameter of the breast implant.

Dear diannamsm,
breast implant type and sizing selection is a complicated process and requires a detailed consultation that includes a discussion of your goals, a detailed examination, and a lengthy discussion. But the decision will always start and end with the patient. When it comes to sizing, we have all of our patients find 3 photos of their desired breast size. We ask for naked breast photos because clothing can obscure the true size (push up bras). Next, we consult with patients and go over the photos and take detailed breast measurements during a physical exam. Next, we using a sizing algorithm to determine a range of implants that will work based on the exam and the measurements.Lastly, during the operation, we use silicone sizers in the operating room to see how the size actually looks in the breast. We sit the patient up in the operating room, while asleep of course, and compare the sizer result with their desired look photos. If it is too small, we start the process over with a slightly larger implant. We don't stop until we get the perfect match.Of all of my breast augmentation patients, every one of them has been happy with their size due to this detailed and meticulous process. You don't want to invest time and money into a result that is either too big or too small.You should discuss your concerns with a board-certified plastic surgeon and make sure that your surgeon understands your goals.
Daniel Barrett, MD
Certified, American Board of Plastic Surgery
Member, American Society of Plastic Surgery
Member, American Society of Aesthetic Plastic Surgery

You would be more comfortable with 450 cc implants than with 550 cc's. However, you may have extra skin to deal with. You might even consider splitting the difference with 500 cc implants, however, these are still considered to be large implants.

More information is needed in order to give you a recommendation. Considerations would be how much natural breast tissue you have as well as your breast width. This combined with your goal size will help determine which implant volume would best help you to accomplish your desired look. Your surgeon is the best one to answer this as she/he has had the opportunity to examine you and talk over your goals in person.