The surgical technique is based on five fundamental steps that need to be followed by the operating surgeon to achieve appropriate results:
Ultrasonic-assisted Lipoplasty differs from traditional Liposuction that the fat is not removed immediately and continuously as the procedure proceeds, so very accurate preoperative markings are important for the specific surgical plan. The outer limits of the area to be treated are outlined, and then topographic markings are made to indicate progressively thicker areas of fat to be liquefied and removed. These topographic markings thus demarcate areas that need greater or lesser amounts or Ultrasonic Energy applied. The usual preoperative evaluation of subcutaneous tissue thickness with the pinch test and the rolling test is helpful in determining where to place these markings before performing UAL.
After the preoperative markings have been made, a large volume of hypotonic fluid is infiltrated into the treatment site. The function of hypotonic solution infiltration is to reduce the density of the subcutaneous tissue. The infusion of this additional fluid facilities cavitation of the subcutaneous fat. The hypo-osmolarity of the solution weakens the lipocyte membrane, swells the cells, and aids in the liquefaction process produced by the Ultrasonic Energy.
Ultrasonic-assisted Lipo-sculpture is often done with the patient neuro-lepto-anesthesized and constantly monitored. In this case the infiltration primarily functions as a local anesthetic when an anesthetic (Lidocaine or Bupivacaine), vasoconstrictor (epinephrine), and sodium bicarbonate are added to the hypotonic solution. The sodium bicarbonate stabilizes the solution and facilitates the effect of the anesthetic. When general anesthesia is used, intra-operative local anesthesia in a lesser dose (Lidocaine, 150 mg/L) is helpful to reduce postoperative pain.
The duration of the procedure and the amount of energy required to liquefy the excess fat vary with the character of the tissue, volume of the planned reduction, and type of lipodytrophy; hypertrophied lipodytrophy is easier to treat than mixed or hyperplastic lipodytrophy.
Less energy is required when the lipocytes contain large volumes of fluid, whereas when the tissues are firm and the fat content and the ratio of tissue to fat are less, more energy is required. For example, for treatment of the inner aspect of the thighs, the application of Ultrasonic Energy at 65% maximum power for 10 to 12 minutes is required to obtain a volumetric reduction of 250 to 300 cc and give good skin stimulation. In a primary session in which virginal areas of mixed lipodytrophy are treated, when the ultrasonic machine is set at 70% power and a long, blunt-tipped probe is used, approximately 45 to 60 cc/min of fat is destroyed.
The use of aspiration simultaneously with Ultrasonic Energy application is not recommended. Concurrent suctioning reduces the volume of fluid that was added to enhance the cavitational effect. The resultant increased density of the tissues being treated logarithmically reduces the degree of cavitation and consequently increases the amount of heat generated and decreases the specificity, with significant side effects.
After ultrasonic treatment of each single area, it is recommended that traditional surgical suction be performed with clear tubing to remove the liquefied fat after cavitation. In this way the aspirate can be carefully monitored visually; when whole adipocytes are observed in the aspirate, suctioning should immediately be ceased. Even small-diameter nasogastric tubing has been satisfactorily employed for this purpose, but it is best to use very slow back-and-forth movements and very thin (2- or 3-mm) Teflon-coated Canula connected to a very low-suction source, not more than 0.2 to 0.4 bar.
The subcutaneous liquefied fat is removed by suctioning the residue of the lipocytes, and the connective tissue containing Autologus collagen remains in place. When the treated areas are clean and empty, they are manually remodeled, and the remnant fluid is expressed with a device developed for this purpose. This maneuver removes the remaining fluid and modifies the shape of the tissues remaining at the treated site. A typical case of lipodytrophy in which six areas (e.g., bilateral treatment of the pretrochanteric area, inner aspect of the thigh, and knee) are treated takes only a short time. However, major body remodeling with massive volume reduction (8,000 cc or more) can easily require up to 4 hours. Overall, UAL requires a longer time (30% longer) than traditional Liposuction, but more conditions can be treated.