Why can't I get a gluteal fold type of excision to fix the sagging and extra folds at bottom of buttock? (photo)

The buttock Shape is flat because of loss of volume not because of excess skin. Excising skin will only make the butt appear flatter  and you will have the added scar. The solution here is fat transplantation. Best of luck.

It is very difficult to determine the exact size and shape implant you will require to best match your ideal butt image without an examination by a board certified plastic surgeon. Not just any board certified plastic surgeon, but one with many years of frequently performing breast augmentation surgery including different approaches, techniques and implant choices. This is because several measurements not to mention your breast characteristics are needed to determine the optimal implant size to obtain your goals. Without knowing these dimensions it would be difficult to make this determination. For example, the existing base width of your buttock will determine, in many cases, the maximal volume per implant profile that you can accommodate. Liposuction of your lower back and fat transfer is also helpful as an adjunct to implants. Using “want to be” photos however are useful if simply provided to the surgeon.

With the right size and shape implant you could possibly avoid the unsightly scar across the bottom of the buttock and have amazing results.  If you fill up that skin with an implant your buttock will be lifted and become more perky.  You will most likely not need any additional surgery for the wrinkling. Be sure to choose a board certified plastic surgeon who specializes in buttock implants and has an extensive photo gallery.  I offer free consultations.  Feel free to contact my office and I can see you.