*3.3.1 Technique*

WAL employs a dual-purpose cannula (**Figure 7**) that delivers pulsating, fanshaped jets of tumescent solution, accompanied by simultaneous suctioning of fatty tissue and infused fluid.

The infiltration solution is pumped through a closed tubing system into a passageway within the device cannula by a variable-force infusion pump. The fluid is sprayed at a 30° angle from the cannula's nozzle tip to loosen the fatty tissue. A separate channel inside the cannula is connected to an integrated suction unit, and washed-out fatty tissue is evacuated from surgical sites. The diameter, arrangement, and sharpness of the openings differ among cannulas. Depending on the intent, the flow rate of the infiltrate as well as the application of variable intensities of negative pressure may be selected. To collect the aspirate without centrifuging

**Figure 7.** *Image of a dual purpose cannula.*

under reduced negative pressures, a sterile container can be connected between the operating cannula and the suction pump.

Long-lasting, maximum anesthesia with minimal side effects is achieved using a two-stage procedure involving two separate tumescent solutions. Preinfiltration, for instance, induces rapid generalized anesthesia and vasoconstriction in the treatment area. Aspiration with a "rinsing solution" containing only small amounts of analgesic is then performed to enhance the analgesia effect and optimize vasoconstriction. The infiltration solution consists of a relatively short-acting analgesic with rapid uptake coupled with a long-acting analgesic with gradual uptake (based on pharmacokinetics). The goal of this formulation is to extend the spectrum of efficacy while keeping each agent's side effects to a minimum [28, 29].

We currently use lidocaine which is considered very safe when used in sufficient doses [30, 31]. We also use epinephrine to induce vasoconstriction.

## *3.3.2 Method*

WAL treatments are recommended for patients who have moderate adiposity with mild to moderate skin laxity, as well as those who want fat augmentation at the same time [32]. Pregnancy, uncontrolled diabetes mellitus, collagen disorders, cardiovascular diseases, and bleeding disorders are considered as an exclusion criteria.

#### *3.3.3 Infiltration of anesthetic solution*

To fully anesthetize the sensory nerves, low volumes of buffered 0.5 percent lidocaine containing 1:200,000 epinephrine (eight parts lidocaine, two parts 8.4 percent sodium bicarbonate) were injected above the fascial planes to anesthetize the surgical area. Separating the skin-fat layers from the underlying muscularfascial layers was made easier by gripping the tissues in a fold.

For more extended periods of anesthesia, smaller amounts of 0.5 percent bupivacaine, up to 50 mL, were injected into sensitive areas over bones (costochondral rib margins, iliac crests, paraumbilicus) and along the boundaries of the planned suctioning areas.

#### *3.3.4 Phase 1: infiltration of tumescent solutions*

With the exception of lidocaine concentration, the tumescent solution used in Phases 1 through 3 contained similar ingredients (**Table 1**). After the skin-fat folds were grasped away from the underlying musculofascial structures, an infiltration cannula was inserted in the deep subcutaneous fat. The Body-Jet system was set to "1," which sprayed the prewarmed wetting fluid at the lowest rate, 90 mL per minute, about 2.5 cm in front of the nozzle. The cannula was slowly moved back and forth in the same tract, resulting in a path of hydrodissection as the spray was directed downward (toward the fascia) on the first pass and upward (toward the


**Table 1.** *Standard wetting solutions.*
