Liposuction removes localized excess fat in the layer between the skin and the muscle. It is a sculpturing procedure and is not used for weight loss. When first described, two methods were used, sharp and blunt. In the sharp method the suction cannula had a sharpened edge which allowed the fat to be carved at the same time as suctioning. However because of problems with the blood supply to the skin blunt cannula are used in most circumstances today.
Surgeons sometimes suction with no fluid introduced into the fatty area, this is the dry technique. However most surgeons feel that adding fluid containing local anesthetic with vasoconstrictors (blood vessel constrictors) reduces postoperative pain and blood loss. This is called the wet technique. Modifications of the wet technique are the superwet and tumescent methods, in which larger volumes of fluid are injected so that the tissue is tense and distended before suctioning. Some surgeons believe that this further reduces bleeding and makes local anesthetic more effective. Suctioning is performed with a metal or plastic cannula connected with tubing to a suction machine. This applies high pressure. by moving the cannula back and forth the surgeon removes tubes of fat. Some surgeons use a hand held suction device without a machine. This is helpful if the fat is to be re-injected.
Other methods aid the break up of fat, one common technique is ultrasonic liposuction which uses an ultrasonic beam to destroy the fat cells either before, or at the time, of fat removal.