Disclosure 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. 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:
History of the Procedure: The use of liposuction was first described in 1976 by Georgio and Arpand Fischer. 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. 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). In 1998, Silberg elaborated on the technique of ultrasound-assisted liposuction as the transmission of a high-frequency ultrasonic field sent through the skin. Since then, several reports, including those by Lawrence and Coleman in 1999 and Lawrence and Cox in 2000, have discussed the procedure. 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.
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. 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). 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. 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:
|
|
||||||||||||||||||||||||||||||||||||||||||
Lab Studies:
Other Tests:
Medical therapy: Antibiotics (eg, cephalothin) are usually given 1 hour before the liposuction procedure. Surgical therapy: Several companies make ultrasound machines that can be used to break up adipose tissue externally with ultrasonic energy. Examples are the Silberg EUA (Wells Johnson; Tucson, Ariz) and the Rich-Mar 510 (Bernsco; Seattle, Wash). Johnson and Cook used a Rich-Mar XUAL (Rich-Mar; Inola, Okla) with a continuous-wave setting at 1 MHz. The adipose tissue is removed with a cannula (tube) inserted through the skin. Liposuction is the suctioning of adipose tissue using cannulas inserted through tiny incisions in the adipose tissue. The cannula is attached to a flexible tube that leads to a suction machine, and the fat is vacuumed out through these tubes. Prior to the day of surgery, the patient has already reviewed the informed consent form. He or she then executes this consent on the day of the surgery. The body areas involved are marked. Then, the patient is taken to the operating room, where he or she is prepared with povidone-iodine solution (Betadine) or other sterilizing solution. Next, local anesthesia is injected for the tumescent technique. The 2 solutions used contain 0.05% or 0.1% lidocaine. The 0.05% solution has 500 mg of lidocaine. The 0.1% has 1000 mg of lidocaine. The tumescent liposuction technique using local anesthesia minimizes blood loss and postoperative discomfort. The surgeon can infiltrate anesthetic solution with either a pressure cuff around the bag of anesthesia or a peristaltic pump and infiltrators. The tumescent local anesthesia technique allows a patient to move intraoperatively into the exact position needed to remove the fat. If many areas are treated, intraoperative sedation or general anesthesia is often used in conjunction with the tumescent anesthetic. Lidocaine toxicity must be considered. Patients should be monitored with a pulse oximeter and ECG during the procedure. Oral diazepam or a similar medication is useful to enhance anesthesia. Oral clonidine, given before the procedure, is helpful in patients with high blood pressure. Some also use small amounts of meperidine (Demerol), promethazine (Phenergan), or midazolam (Versed) to enhance anesthesia. Preoperative details: Routine preoperative screening is performed. Marking must be diligently performed prior to tumescence because many contours are lost or altered following its injection. Intraoperative details: The XUAL machine is used to break up adipose tissue before liposuction begins. These machines produce 1 MHz of ultrasound energy in a continuous or pulsed cycle. The maximum power is 30 W or 3 W/cm2. The sound heads provided are 5 or 10 cm. The continuous cycle induces more tissue destruction than the pulsed cycle. Note that that a 1-MHz beam is reduced to half intensity at 48 mm of fat. In 2000, Lawrence and Cox applied external ultrasound at 2-3 W/cm2 in a continuous-wave cycle for 10 minutes to the treatment side. A coupling gel is used to prevent air interference at the skin-transducer interface. Before the ultrasound is applied, the areas to be treated are infused with tumescent anesthesia. Ultrasound is applied to the treatment areas using circular strokes continuously for 10 minutes to each side. The recommended duration of treatment is 1-2 minutes for each area 1.5-times the size of the transducer face. For most areas, this is 10-15 minutes per treatment area. The transducer must be moved continuously to prevent overheating. After the ultrasound application, standard tumescent liposuction is performed. Postoperative details: Postoperatively, pain control needs are minimal. Usually, extra-strength acetaminophen is sufficient. Some practitioners continue to administer antibiotics with gram-positive coverage for 7-10 days. The reasons for this are unclear. Most apply elastic (ACE) bandages, compression garments, or French tape compression to areas that have been liposuctioned to prevent seromas and bruising and to decrease soreness in these areas. Follow-up care: Patients can engage in noncontact sports immediately as tolerated. They cannot engage in contact sports or high-impact sports for approximately 2 weeks. Compression garments can be used postoperatively. Optimally, patients should wear these 12-24 h/d for approximately 2-4 weeks (as tolerated).
Rarely, XUAL can cause bruising, skin burn, and seromas. Skin necrosis, fibrosis, pigmentation alteration, and sensory alteration are also possible. Rarely, ulceration and a rubbery feel to edematous tissue have been described. The complications of tumescent liposuction are well described. In rare cases, cardiac problems can occur. Sometimes after these procedures, surface irregularities and skin laxity can develop.
In 2000, Mendes described less resistance to the cannula with a more rapid removal of fat, and the aspirated tissue showed less blood content with intact viable fat cells. His patients reported less pain and discomfort on the ultrasound-treated sides, and he noted less swelling and bruising, with superior skin shrinkage. Mendes concluded that clinical recovery was enhanced by the external ultrasound, and no complications were reported. In 1999, Johnson and Cook also achieved excellent results with XUAL. They noted greater cannular maneuverability; an increase in the proportion of supernatant fat observed in the aspirate; and a decrease in postoperative ecchymosis, swelling, and discomfort. Lawrence and Cox experienced no advantages with XUAL. Overall, the outcomes and prognoses appear to be good with XUAL. The only question is whether any benefit is actually incurred with XUAL over tumescent liposuction alone. Conversely, the results of internal ultrasonic-assisted liposuction in areas of fibrous-fatty tissue and for large-volume aspirations are well documented. The learning curve for the internal ultrasonic-assisted liposuction technique is longer than that for the external technique
In 2000, Lawrence and Cox reported that when corrected for the placebo effect of external ultrasound application prior to tumescent liposuction, no advantage was achieved for doctor or patient. In most cases, the liposuction surgeon could detect no difference in the rate of extraction, color of fat, or resistance to the cannula. Most patients actually found greater discomfort on the side treated with high-intensity ultrasound. In 1999, Lawrence and Coleman reported that XUAL was helpful and effective. Currently, most authorities believe XUAL is ineffective. Future studies must define the exact settings to use with XUAL and which patients will benefit from XUAL. As with most techniques, the success of XUAL is probably operator dependent; thus, this factor must be evaluated in future studies. XUAL has not yet achieved widespread acceptance or popularity. For excellent patient education resources, visit eMedicine's Procedures Center. Also, see eMedicine's patient education article Liposuction.
Liposuction, Techniques: External Ultrasound-Assisted excerpt | |||||||||||||||||||||||||||||||||||||||||||
){kind=small}
