Liposuction has been the most common plastic surgical procedure done in the United States. In 2007 over 450,000 patients underwent liposuction. Liposuction is best used to reduce pockets of fat which have been unresponsive to weight loss. Liposuction removes fat only and does not remove skin. For this reason it is usually only used as an adjunct to skin removal for patients who have lost a lot of weight. There are several methods of liposuction available including traditional liposuction, Vaser or ultrasonic liposuction (UAL) and power assisted liposuction (PAL). A plastic surgeon may use one or more of these techniques in treating a patient depending on the areas being treated. For example fibrous areas such as the back or male chest are usually treated with either Vaser or PAL rather than traditional liposuction.