Safety and Complications > Risks of Ultrasonic Liposuction
Risks of Ultrasonic Liposuction
Ultrasonic Assisted Liposuction (UAL)
Ultrasonic assisted liposuction (UAL) is any modified liposuction technique that delivers ultrasonic energy to subcutaneous fat in an effort to facilitate traditional negative-pressure liposuction. UAL has become less popular because of an increased awareness among liposuction surgeons that UAL is associated with increased risks of complications.
The concept of UAL is intuitively appealing. A piezoelectric crystal converts electric energy to rapid (ultrasonic) vibrations and heat that are transmitted to a small metal rod or paddle and thus injure living tissue. Ultrasonic energy delivers a combination of vibratory mechanical energy and thermal energy to subcutaneous fat.
Safety of UAL is controversial. One study of 250 consecutive UAL patients concluded that internal UAL is "both safe and effective" despite three cases of dermal necrosis (1.2 percent), 28 postoperative seromas (11.2 percent), and 35 patients with Reston foam blisters. (Maxwell GP. Ultrasound-assisted lipoplasty: a clinical study of 250 consecutive patients. Plast Reconstr Surg 101:189-202,1998). Based on this report, most experienced liposuction surgeons have concluded that UAL is less safe than Tumescent Liposuction with microcannulas.
Two Types of UAL
There are two types of UAL: Internal UAL and external UAL. Internal UAL delivers ultrasonic energy directly to subcutaneous fat by a metal rod or cannula inserted through an incision in the skin. External UAL delivers ultrasonic energy to subcutaneous fat by means of applying a paddle-shaped instrument directly to the overlying skin.
A Brief History of Internal UAL
Europeans were the first to embrace internal UAL. After an initial period of
enthusiasm for internal UAL, it was eventually rejected by the majority of
European liposuction surgeons because of an unacceptable incidence of complications.
Despite the misgivings of many European surgeons, internal UAL was subsequently
introduced into North America. Many surgeons tried internal UAL because it
was promoted as the "cutting-edge" of cosmetic surgical technology. Because
of insufficient proof of safety, the FDA (U.S. Food and Drug Administration)
never approved the sale of internal UAL devices for liposuction. Nevertheless
equipment manufacturers and some prominent surgeons promoted internal UAL,
and many surgeons purchased these devices with the intention of using them
on liposuction patients. Eventually the risks of UAL became apparent, and sales
of UAL devices plummeted. The company that sold most of the Internal UAL devices
in America has declared bankruptcy.
A Brief History of External UAL
External UAL was initially promoted by several enthusiastic liposuction surgeons who made statements that were based on subjective opinion rather than objective scientific data. It soon became apparent that external UAL provided no benefit, and it is now rarely used.
UAL Causes Blood Clots
UAL causes blood clots in the small blood vessels. Internal UAL produces heat
and elevates the temperature of targeted fatty tissue. However, it can also
increase the temperature within the blood vessels that supply the overlying
skin. Elevation of the temperature within blood vessels causes blood clots
within the vessels. If the blood vessels that supply an area of skin with oxygen
becomes blocked by clots, then the skin will die. Internal UAL may literally
create a large area subcutaneous thermal injury.
Injury to Peripheral Nerves
Injury to peripheral nerves is possible with UAL. Patients who have had internal UAL appear to have an increased incidence of prolonged numbness consistent with injury to sensory nerves. The neurosurgery literature has documented the injurious effects of ultrasound on peripheral nerves. The potential for ultrasonic energy causing damage to peripheral nerves suggests that the risks of using UAL in arms, legs, neck and face may outweigh any potential benefits.
UAL Causes Seromas
A seroma is a fluid-filled cavity beneath the skin containing serum (clear
yellow fluid) that can persistent for weeks or months. Internal UAL causes
the formation of seromas in 15% to 70% of patients. Advancing the internal
UAL cannula too slowly through fat or using too much ultrasonic energy, causes
seromas by damaging surrounding tissues. In response one manufacturer has modified
its recommendations and "solved the problem" by recommending that surgeons
reduce the amount of internal ultrasonic energy that is delivered to subcutaneous
fat. In other words, do less ultrasonic liposuction and reduce the incidence
of problems.
External UAL and Manufacturer's Warnings
The external UAL device is the same ultrasound apparatus traditionally used by physical therapists. These ultrasound machines are associated with definite risks and dangers. The manufacturers of external ultrasound devices provide instructions that state external ultrasonic devices should not be used over the heart, the ovaries, or over a large artery such as the carotid artery. Manufacturers' warnings should prohibit the use of external UAL for liposuction of the male chest, the female abdomen, or on the neck or chin areas. If a surgeon uses external UAL on the female abdomen, then the manufacturer's warnings should be included in the information about UAL given to the patient.