"For hundreds of years, everyone has believed that the fat on the face is one confluent mass, which eventually gets weighed down by gravity, creating sagging skin," said Dr. Joel Pessa, assistant professor of plastic surgery and the study's lead author.
"In our studies, however, we were surprised to find that this is not the case; the face is made up of individual fat compartments that gain and lose fat at different times and different rates as we age."
The study involved injecting different types of dye into facial cavities of 30 cadavers. Despite at least 24 hours of settling time, the dye, rather than permeating the entire face, stayed in separate areas - showing that individual facial compartments have boundaries between them that act like fences. These fences, which seem to be composed of fibrous tissue, allow the face to maintain its blood supply should it become injured.
Dr. Pessa said the face resembles a three-dimensional puzzle, with fat divided into distinct units around the forehead, eyes, cheeks and mouth. Facial aging is, in part, characterized by how these separate compartments change as we grow older.
A youthful face is characterized by a smooth transition between these compartments. As people age, contour changes occur between these regions due to volume losses and gains as well as repositioning of the compartments. Eventually, this can result in sagging or hollowed skin and wrinkles.
"This is a revolutionary way of viewing facial anatomy. It not only tells us how we age, it shows us why we age the way we do, and why every part of the face, from the eyelids to the cheeks, ages differently," said Dr. Rod Rohrich, chairman of plastic surgery and senior author of the study. "This will help plastic surgeons around the world not only understand how we can better rejuvenate the face, but how people age as a physiological process."
This breakthrough could have tremendous implications in helping plastic surgeons target facial "trouble" areas and use injectible fillers to add volume to individual sections of the face. It could also aid in developing new and improved cosmetic and reconstructive surgery techniques, Dr. Rohrich said.
"Understanding how fat is compartmentalized will allow us to be very accurate and precise in how we approach facial rejuvenation," Dr. Pessa said. "This gives us an algorithm, or scientific approach, to help ascertain what areas of the face may need extra fat to combat the aging process. It also is a major breakthrough in facial anatomy that will have major implications for future studies on aging and possibly hold clues to the study of other diseases such as obesity, diabetes and cancer."