Hi, I thought I would pitch in my two cents on the matter.
From my understanding, reduction of the physical malar bone is not exactly the source of facial sagging post-op. Rather, it is the dissection required for the surgeon to access the bone to cut it in the first place which determines sagging. The cheekbones hold up the flesh of your face and your cheeks - there is no other bone that hold this flesh up in place. During surgery, to make the bone cut, the surgeon needs to dissect some of your tissues from the cheekbone. That's why you need to find an extremely skilled surgeon who performs this surgery with limited dissection so that your flesh doesn't sag downwards due to gravity.
When you detach too much of the cheekbone-flesh attachments, it can't hold itself up - so what happens? Gravity pulls it downwards.
The typical amount of bone removed shouldn't cause loose skin. Most case studies I have read have 3-5mm of bone removed from the body of the malar bone, which is a reasonable amount. Skin/scar contraction should counteract this. I have read one case study from China where they even removed up to 8mm bilaterally from the malar body
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