Will Liposuction on Outer Thighs Deform the Butt?

In general, Lipo of the outer thigh is all positive in terms of how it affects the buttock area. Since they both contribute to the same circumference, the way clothes fit is typically much better. The tricky part is where it tapers into the upper posterior thigh just below the buttock. Sometimes there is a distinct roll called the "banana roll." This area is part of a sort of column of tissue supporting the buttock so if lipo is not done very carefully there then you lose support. So how the lipo is tapered and transitioned into the buttock and the posterior thigh is important to avoid a saggy bottom line.

Thank you for your question. It is hard to provided with a valid medical opinion without photos.  I would suggest to be treated by board certificated plastic surgeon with experience in this procedure, to get the best desired results.
Kind Regards,Dr. Emmanuel Mallol Cotes.-

Liposuction of the outer thighs (saddlebags) can enhance the appearance of the buttock by removing the attention of the unwanted outer thigh fat and highlighting the preexisting shape of the buttock.
There can be an infragluteal mound, referred to as a banana roll, that is located adjacent to the outer thigh fat and runs horizontally under the buttock crease. It can form a double crease. If this is thinned out too much, the support for the buttock decreases and there can be a drooping of the buttock.
Finally, a naturally found condition exists called pseudosaddlebags, in which weak buttocks fall down and push on the outer thigh fat extending it out to the side. If the buttocks are clenched one sees this bowing of outer thigh fat reduce its convex curvature immediately. In order to improve this outer fat appearance, the buttock may need to be addressed.

Liposuction is such a great procedure and easy to undergo under local anesthesia and makes butts look better when doing the outer thighs usually. It is liposculpturing that helps make the areas look so nice and natural.  

The outer thighs and buttocks need to be sculpted together during liposuction. These two areas relate to each other so closely that the effects of one on the other must be considered in planning the procedure.