eMedicine Specialties > Plastic Surgery > Body Contouring

Liposuction, External Ultrasound-Assisted

Author: Noah S Scheinfeld, MD, JD, FAAD, Assistant Clinical Professor, Department of Dermatology, Columbia University; Consulting Staff, Department of Dermatology, St Luke's Roosevelt Hospital Center, Beth Israel Medical Center, New York Eye and Ear Infirmary; Private Practice
Coauthor(s): Marc S Zimbler, MD, FACS, Director of Facial Plastic and Reconstructive Surgery, Director of Residency Education, Department of Otolaryngology, Head and Neck Surgery, Beth Israel Medical Center; Mia Talmor, MD, Assistant Professor, Department of Surgery, Weill Medical College of Cornell University
Contributor Information and Disclosures

Updated: Dec 19, 2006

Introduction

External ultrasound-assisted liposuction (XUAL) is a new technique that requires traditional aspirative liposuction after the application of high-frequency ultrasonic fields delivered through the skin into wetted tissue. That is, sound waves are transmitted to the tip of the cannula to liquefy fat before the fat is removed by suction.

The use of high-intensity, high-frequency external ultrasound before liposuction has been reported to enhance the ease of fat extraction, increase the amount of fat extracted, and decrease patient discomfort during liposuction. XUAL must be differentiated from internal ultrasound-assisted liposuction in that the ultrasonic energy is applied through the skin rather than through a specialized cannula as in internal ultrasonic liposuction.

In 2003, Rohrich and colleagues noted that ultrasound-assisted liposuction has recently emerged as a safe and effective method for the treatment of gynecomastia.¹ The technique is particularly efficient in removing dense, fibrous breast tissue in men, while offering advantages in minimal external scarring. Rohrich and colleagues noted that a new system of classification and graduated treatment is proposed, based on glandular versus fibrous hypertrophy and the degree of breast ptosis (skin excess). Rohrich's series of 61 patients with gynecomastia at the University of Texas Southwestern Department of Plastic Surgery demonstrated an overall success rate of 86.9% using suction-assisted lipectomy (1987-1997) and ultrasound-assisted liposuction (1997-2000). Rohrich found ultrasound-assisted liposuction to be effective in treating most grades of gynecomastia. Excisional techniques are reserved for severe gynecomastia with significant skin excess after attempted ultrasound-assisted liposuction.

Other means of liposuction include the following:

• Suction-assisted liposuction is the traditional method. In this type of liposuction, the surgeon removes fat by inserting a cannula that is connected to a vacuum pressure unit and directing the cannula through tiny incisions into areas to be suctioned.
• In the external ultrasound-assisted liposuction method, the external ultrasound waves alter fat cells. The area is injected with fluid that contains local anesthetic to transmit ultrasonic energy, and liquefied fat is removed by suction.
• In power-assisted liposuction, a cannula with a back-and-forth motion of the tip passes through tissue to suction out fat and fibrous or scarred tissue with reduced effort.
• The Vibration Amplification of Sound Energy at Resonance (VASER) System (Sound Surgical Technologies LLC, Louisville, Colo) is another method of liposuction. In VASER-assisted liposuction, intermittent or continuous bursts of ultrasonic energy can be used to break up fat cells, which are then removed by suction.

History of the Procedure

The use of liposuction was first described in 1976 by Georgio and Arpand Fischer.² Tumescent liposuction is also called standard liposuction, liposuction, lipoplasty, liposculpture, liposculption, and suction-assisted lipoplasty. This type of liposuction has been performed in the United States since 1982. First, the surgeon fills the fat with tumescent fluid (a solution that contains saline and local anesthetic). Then, the fat is suctioned with long thin rods. The procedure can now be performed through a few small incisions, which can be hidden with natural skin creases. The tumescent technique may reduce blood loss and alleviate pain. The local anesthesia may be supplemented with intravenous sedation or general anesthesia.

In 1987, Scuderi et al introduced the use of ultrasound as an emulsifying modality for adipose tissue.³

In 1992, Zocchi outlined the technique of ultrasonic liposculpturing, which involved 3 fundamental steps: (1) preparation of the areas to be treated with a large infiltration of a special solution, (2) treatment of the areas with ultrasonic energy through special titanium probes, and (3) manual remodeling of the treated areas to eliminate the fluid from the burst adipocytes (fatty acids).⁴

In 1998, Silberg elaborated on the technique of ultrasound-assisted liposuction as the transmission of a high-frequency ultrasonic field sent through the skin.⁵ Since then, several reports, including those by Lawrence and Coleman in 1999 and Lawrence and Cox in 2000, have discussed the procedure.^6,7

Problem

Soft tissue injuries, orthopedic trauma, and pain relief for chronic pain conditions all can be treated with external ultrasound. The action of manual liposuction can be time consuming and physically taxing. In this regard, ultrasound appears to offer the advantage of breaking up adipose tissue to facilitate liposuction.

Internal ultrasound-assisted liposuction can cause skin necrosis and seromas. Therefore, interest has been garnered in the application of external ultrasound prior to liposuction. Theoretically, external ultrasound should soften or disrupt adipose tissue and (1) facilitate the task of suctioning adipose tissue, (2) make the patient more comfortable during and after the procedure, and (3) improve the quality of the aspirate by decreasing the amount of blood.

Frequency

XUAL is not widely used, and studies done in 2000, 2001, 2002, 2003, and 2004 did not conclusively demonstrate its effectiveness.

XUAL is a type of UAL in which the ultrasonic energy is applied from outside the body, through the skin, making the specialized cannula of the UAL procedure unnecessary.

While UAL can result in skin necrosis (death) and seromas, XUAL can, in theory, avoid this by applying the ultrasound externally.

XUAL is also potentially useful because (1) the external location of the ultrasound device can lead to less discomfort for the patient during and after the procedure; (2) the external location of the device means the probe does not physically touch much tissue and, therefore, can decrease blood loss; (3) it allows superior access through scar tissue; and (4) it is not constrained by internal structures and can, therefore, be used to treat larger areas.

Pathophysiology

Ultrasound causes tissue destruction via 3 mechanisms: (1) cavitation, (2) micromechanical disruption, and (3) thermal damage. Articles on internal ultrasound-assisted liposuction largely attribute the destruction to unstable or transient cavitation. Reports that are not about liposuction suggest that the disruptive biologic effects of external ultrasound are due to micromechanical disruption or tissue heating.

The ultrastructure of cells is affected by ultrasound. It disrupts membranes and affects calcium influx, which can stimulate mast cell degranulation. Ultrasound can induce fibroblast activity and enhance collagen production. It can stimulate endothelial cell activity and new capillary formation in chronically ischemic tissue.

Indications

Patients with localized increased adipose tissue benefit from liposuction. This condition is termed lipodystrophy, and, even if the patient is at or below their ideal weight, fatty tissue is present in excess in these areas. Overweight patients may also have lipodystrophy, but, for generalized obesity, diet and exercise are the treatments rather than large-volume liposuction. The best liposuction results involve healthy patients with good skin tightness and localized deposits of fat.⁸ Good candidates for liposuction should have realistic expectations and should not be obese. Some of the adverse effects of liposuction include localized pain and skin trauma. Some patients must have multiple procedures if they have more fat than can safely be removed in one operative sitting. In rare cases, patients can experience problems with the anesthesia.

Ultrasonic liposuction appears most useful for treating very large or very fibrous areas. XUAL allows much easier access through scar tissue. Treatment of male breasts and retraction of the skin on necks are especially appropriate areas for XUAL treatment.

In 2004, Shi and colleagues reported external ultrasound-assisted liposuction performed on 500 patients (595 sites).⁹ They recorded the volume of anesthetic drugs and the aspirated pure fat, as well as the body contour variations of every area at 1-3 months postoperatively. The decreased dimensions at different body sites after liposuction were compared and analyzed. The volumes of the anesthetic liquid and the aspirated pure fat were the greatest in the waist-abdomen and the thigh.

After liposuction, the circumstances in different body areas were all decreased to certain degrees. Along with the severity of obesity, changes in the waist-abdomen became more obvious, and the decreases of the umbilical circumference and the minimum and maximum waist circumferences were prone to be less. However, when the minimum waist circumference was more than 111 cm, obvious changes occurred in the umbilical. Meanwhile, the upper middle part of the thigh and the upper arm showed larger variations than the lower part.

The ultrasound-assisted liposuction caused less blood loss and pain and resulted in smooth skin without severe complications. Shi and colleagues therefore noted that external ultrasound-assisted liposuction is a safe, effective, and easily acceptable operation for body contour remodeling. The body circumference variation may have its intrinsic rule, which, to some extent, is meaningful for conducting clinical inquiry and forecasting surgical results.

In 2004, Zhang tried to find a safe, effective, and simple method for liposuction in the upper legs.¹⁰ After appropriate choices were made regarding the type of incision, the range of suction, and the method for liposuction, 32 patients received external ultrasound-assisted tumescent liposuction in the upper legs with local anesthesia. All the patients recovered smoothly and quickly from the operation and had satisfactory effects of weight reduction and shaping of the legs. No obvious complications occurred in these cases. Zhang concluded that external ultrasound-assisted tumescent liposuction is a safe, effective, and simple technique for removing local fat deposit in the upper legs.

Relevant Anatomy

Adipose tissue is the tissue removed during liposuction procedures. The most common areas involved are the abdomen and thighs in women and the abdomen and flanks in males.

Contraindications

• Patients who are extremely obese or in poor health, especially with cardiac problems, should not undergo XUAL.
• Only a limited amount of fat should be removed at each session.
• Some warn against performing liposuction around the neck and upper chest because of the possibility of creating cavity effects.
• Ultrasonic energy can cause air emboli, a possibility that should be considered when selecting sites for the procedure. To date, this injury has not been reported; it is more likely to be a problem with internal ultrasound than with XUAL.

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