Lipoplasty: Ultrasound-Assisted Lipoplasty (UAL)

ARLINGTON HEIGHTS, IL (Sept. 1997) — Ultrasound-assisted lipoplasty (UAL) is a relatively new method of liposuction that uses ultrasonic energy to liquefy fat before it is removed by suction. Because the fat is liquid at the time it is evacuated, removal is smoother and mechanically more efficient. For this reason in the hands of a plastic surgeon trained in the use of ultrasonic technology, UAL may permit the removal of larger volumes of fat with increased ease and proficiency.

Not all plastic surgeons feel that UAL is superior to conventional liposuction, and experienced plastic surgeons using conventional techniques routinely report results equivalent to those obtained with UAL. Patients should keep in mind that the most important factor in obtaining a good aesthetic result from liposuction is the skill of the surgeon and not necessarily the specific liposuction technique. In addition, UAL currently is not recommended for removing fat from areas such as the face, neck, knees and inner thighs.

Overview of Conventional Liposuction (SAL)

Conventional liposuction, also called suction-assisted lipoplasty (SAL), was introduced in the United States in the early 1980s. It was a revolutionary technique that, for the first time, allowed surgeons to reshape the body through tiny incisions, usually less than one-half inch long.

In conventional liposuction, a slender tube called a cannula is inserted into the fatty tissue of the area to be treated. The cannula is attached at one end to a suction device. After the fat is dislodged by the surgeon's movement of the cannula, it is literally vacuumed away. Suctioning may be performed on the deep or more superficial layers of fat.

The technique of "tumescent liposuction" has been found to result in decreased blood loss from fat suctioning. The tumescent technique is characterized by the infusion of large volumes of dilute anesthetic solution into the areas to be treated with liposuction.

Overview of Ultrasound-Assisted Lipoplasty

Ultrasound has been used in the United States for the surgical removal of tissues, other than fat, for more than 20 years in such specialties as general surgery, neurosurgery and ophthalmology. Ultrasound for fat removal has been used in Europe for more than five years and in the United States for more than two years.

In UAL, following infiltration of fluid into the areas to be treated, a probe is placed beneath the skin into the fatty tissue. The probe is attached to an ultrasound energy source that causes the tip of the probe to vibrate very rapidly (20,000 times per second). These short, rapid vibrations create an energy field which liquefies the fat, after which a suction cannula is used to vacuum it away.

Advantages of UAL

UAL is particularly advantageous for removing large volumes of fat in areas of the central body such as the hips. It is also effective in treating areas containing fibrous tissue, such as the back and for treatment of the enlarged male breast, a common condition called gynecomastia. The vibrations at the tip of the probe help to ease passage of the suction cannula through the tissue. UAL may, in some instances, decrease postoperative bruising and swelling.

Some surgeons using UAL believe that passage of the ultrasound probe near the undersurface of the skin alters the collagen and causes skin tightening. While there is some clinical support for this claim, it has not been conclusively shown that more significant skin tightening occurs with UAL than with conventional liposuction.

Disadvantages and Risks of UAL

The ultrasound probe requires larger access incisions than the cannula used in conventional liposuction. Depending on the areas to be treated, some patents may find this objectionable.

Since UAL uses ultrasonic energy to liquefy the fat, there is the risk of burns to the skin or the deeper tissues. In addition, patients undergoing UAL have been shown to have a higher incidence of seromas (temporary collections fluid in the treated areas). Usually, these fluid collections are gradually absorbed by the body over several weeks to months and are unlikely to affect the final result. Occasionally, they may need to be removed by needle aspiration or surgical drainage. UAL otherwise has risks and complications similar to those associated with conventional liposuction.

Regulatory Status of UAL Devices

To date, four manufacturers of UAL equipment have received 510K approval from the U.S. Food and Drug Administration (FDA) to market their devices for soft-tissue aspiration.

External UAL

External UAL (E-UAL), which uses external ultrasound waves that may alter fat cells within the body, is still in the earliest stages of scientific evaluation. If it is shown to have benefit, most likely it will be as an adjunct to, rather than a replacement for, either conventional liposuction or UAL.

Currently, there are two types of E-UAL systems. Both involve the transmission of energy using ultrasound generators and transducers applied externally to the skin. Both require that the area to be treated must first be infiltrated with fluid in order to transmit the ultrasonic energy and allow for patient comfort. The major differences between the two systems are the use of one versus two transducers, and variations in the technique of fat removal. One system uses suction to remove the liquefied fat. The other method follows the external ultrasound treatment with massage and the application of compression foam and garments.

The exact mechanism by which the results of E-UAL are obtained is not understood, and there are no published studies to date. Risks include injury to the skin or underlying structures from prolonged use or unpredictable delivery of ultrasonic energy.

Finding a Surgeon

Because any physician can legally advertise as a "plastic" or "cosmetic" surgeon, even without any formal surgical training, prospective patients must exercise caution. New technologies such as UAL may appeal to such doctors as a method of marketing their cosmetic surgery practices.

In selecting a surgeon to perform body contouring, whether it is conventional liposuction or UAL, a potential patient should be certain that the doctor:


The American Society for Aesthetic Plastic Surgery (ASAPS), is recognized as the world's leading organization devoted entirely to aesthetic plastic surgery and cosmetic medicine of the face and body. ASAPS is comprised of over 2,600 Plastic Surgeons; Active Members are certified by the American Board of Plastic Surgery (USA) or by the Royal College of Physicians and Surgeons of Canada and have extensive training in the complete spectrum of surgical and nonsurgical aesthetic procedures. International Active Members are certified by equivalent boards of their respective countries. All members worldwide adhere to a strict Code of Ethics and must meet stringent membership requirements.


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