How dangerous is liposuction of the thighs for a healthy 80 y.o. woman?

A healthy patient of any age may be a good liposuction candidate. Something to consider, though: The goal of having liposuction is to tone areas of the body where pockets of fat cause bulges. At 80, it's unlikely the skin retains enough elasticity to "snap back" into place once fat is removed from the thighs. I recommend carefully considering the likely results of such a procedure and whether you would be exchanging one aesthetic concern (bulging thighs) for another (sagging skin). A consultation with a board-certified plastic surgeon will help you make this decision.  

In general, as our skin ages, it responds more poorly to liposuction. The best candidate for inner thigh liposuction in their 20-30's when their skin has great elasticity. As a patient's skin ages, I find liposuction results to be poor and guide them against it. Likely at age 80, you are better served with an excisional technique (thigh lift) than lipocontouring. But I would still recommend a formal consult and evaluation by a board certified Plastic Surgeon to answer all your questions. Best of luck.

At age 80, your skin will not snap back and you will have sagging, exchanging one problem for another. There could also be cognitive issues after anesthesia.  I'm sorry but this is not a procedure I would consider performing.  Best wishes.