External Ultrasound-Assisted Liposuction Treatment & Management

Antibiotics (eg, cefazolin) are usually administered 1 hour before the liposuction procedure.

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.

Liposuction is the suctioning of adipose tissue using thin tubes, or 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 and collected in a large receptacle for measurement of the volume removed.

Prior to the surgery, the patient reviews the informed consent with his or her surgeon, when any questions may be answered and the details of the procedure discussed. The body areas to be addressed are marked, ensuring that both the patient and the surgeon understand which areas will be addressed. Then, the patient is taken to the operating room, where he or she is prepared with povidone-iodine solution (eg, Betadine) or other sterilizing solution.

Next, local anesthesia and epinephrine is injected for the tumescent technique. The two 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 uses local anesthesia along with epinephrine to minimize blood loss and postoperative discomfort. The surgeon can infiltrate anesthetic solution with either a pressure cuff around the bag of tumescent solution 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; this may be safely administered by an anesthesiologist or certified anesthetist.

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 clinicians also use small amounts of meperidine (Demerol), promethazine (Phenergan), or midazolam (Versed) to enhance anesthesia.

Routine preoperative screening is performed. Marking must be diligently performed prior to tumescence because many contours are lost or altered following its injection.

The external ultrasound-assisted liposuction (UAL) 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.^[12]

A coupling gel is used to prevent air interference at the skin-transducer interface. Before the ultrasonic energy is applied, the areas to be treated are infused with tumescent anesthesia. Ultrasound is applied to the treatment areas using circular strokes continuously, usually for 10 minutes on 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. Note that newer machines have been developed that deliver higher intensity ultrasonic forces of 2-3 MHz, which are associated with greater destruction of adipose cells.

Postoperatively, pain control needs should be minimal. Usually, extra-strength acetaminophen is sufficient. Some practitioners continue to administer antibiotics with gram-positive coverage for 7-10 days. Most practitioners apply elastic (eg, Ace) bandages, compression garments, or French tape compression to areas that have been treated to prevent seromas and bruising and to decrease soreness in these areas. Patients are often concerned about postoperative leakage of tumescent fluid from incision sites for up to several hours. Patients should be reassured that such leakage is common.

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 and should be used postoperatively. Optimally, patients should wear these 12-24 h/d for approximately 2-4 weeks (as tolerated).

Rarely, external UAL can cause bruising, skin burn, and seromas. Skin necrosis, fibrosis, pigmentation alteration, and sensory alteration are also possible. Rarely, skin 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, surface irregularities and skin laxity can develop after these procedures.

In 2000, Mendes described less resistance to the cannula with a more rapid removal of fat; the aspirated tissue removed in this fashion revealed less blood content with intact viable fat cells.^[2] Patients reported less pain and discomfort on the areas treated with ultrasound; less swelling and bruising and superior skin shrinkage were also noted in the ultrasound-treated areas. No complications were reported, and Mendes concluded that clinical recovery was enhanced by external UAL. In 1999, Johnson and Cook also achieved excellent results with external UAL.^[18] They noted greater cannula maneuverability; an increase in the proportion of supernatant fat observed in the aspirate; and decreases in postoperative ecchymosis, swelling, and discomfort.

Overall, the outcomes and prognoses appear to be good with external UAL. Comparatively, the results of internal UAL in areas of fibrous-fatty tissue and for large-volume aspirations are well documented. The learning curve for the internal UAL technique is longer than that for the external technique.

In 2000, Lawrence and Cox reported that when corrected for the placebo effect, external ultrasound application prior to tumescent liposuction achieved no advantage for doctor or patient.^[12] In most cases, the surgeon could detect no difference in the rate of extraction, color of fat, or resistance to the cannula. Most patients reported greater discomfort on the side treated with high-intensity ultrasound compared to the side treated with very low-intensity ultrasound.

In 1999, Lawrence and Coleman reported that external UAL was helpful and effective.^[11] Ferraro's 2008 study reports that external UAL is a highly effective noninvasive modality that induces cell-to-cell contact, which leads to loosening of collagen fibers, allowing adipose cells to be removed mechanically with less effort and local tissue damage.^[4] At higher frequencies, external UAL causes complete cellular destruction of adipose cells.^[4]

Currently, most authorities believe external UAL is ineffective. In their review of various liposuction techniques, Heymans et al found that vibroliposuction techniques provide the safest, most precise form of lipectomy without the complications associated with internal UAL.^[1] Future studies must define the exact settings to use with external UAL and which patients will benefit from external UAL. As with most techniques, the success of external UAL is likely operator-dependent; thus, this factor must be evaluated in future studies. External UAL 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.