I had already had lipo and didn't have much fat, but somehow Dr. Bruno still managed to give me a much curvier rear end (he even improved the results of my previous lipo in the process!). He really defined my lower back and added a lot of volume to the top of my buttocks for an amazing effect. I went from almost totally flat with no noticeable transition from my back to my rear end to having a curvy rear profile that looks amazing and really improved the fit of all of my clothes and how I look in them.
It's a little tough to move around the first couple of days and you should make sure that after the surgery you're able to stay off of your rear end for a while. But it's definitely worth it!