3.1 Introduction

Excess body fat is a significant problem in the U.S. Data collected by the CDC reports that approximately one-third of adults are overweight (BMI >25 and <30). ¹ Body contouring, the removal of unwanted localized fat deposits, is a very popular cosmetic procedure. The American Society of Plastic Surgeons (ASPS) reported that over 635,000 procedures (both surgical and noninvasive) were performed in 2018 for the reduction of unwanted fat. ² Liposuction, the surgical removal of localized subcutaneous fat deposits, is the most popular cosmetic surgical procedure performed. ² Noninvasive body contouring procedures have entered the market as an alternative method of improving body contour without surgical intervention. According to ASPS, noninvasive fat reduction is now the 7th most requested non-surgical procedure. ²

3.2 Hyperthermic Treatment

Tissue response to hyperthermia has been well researched. The studies of the effect of hyperthermic treatment on adipocytes demonstrated that a moderate rise in temperature of 5–10°C (42–47°C) will cause cellular and tissue injury by a variety of mechanisms including cell membrane permeability changes, denaturation of cellular proteins and inhibition of DNA synthesis and repair. ³ These injuries will result in delayed cell death or apoptosis. ⁴ Cellular and tissue injury will stimulate the body’s innate and adaptive immune surveillance system resulting in clearance of the damaged adipocytes.

3.3 Laser Tissue Interaction

Lasers have been used in medical treatments for decades. The particular wavelength of laser light chosen for a treatment is dependent on the physical properties of the tissue and the absorption properties of the wavelength. The energy absorbed by the tissue is converted into heat resulting in the controlled hyperthermia and subsequent injury to the targeted tissue.

SculpSure from Cynosure corporation is the first FDA approved externally applied device for laser fat reduction. The 1060 nm wavelength chosen for the noninvasive laser fat reduction device SculpSure was selected due to its optical properties in skin and fat. When compared to other visible or infrared wavelengths, 1060 nm is known to have minimal absorption in the skin making it a more efficient wavelength for delivering laser energy to the subcutaneous adipose tissue target without injury to the overlying skin. ⁵ This wavelength has a relatively higher penetration depth into subcutaneous adipose tissue, when compared to other wavelengths, facilitating spreading of the heat effect over a larger volume without creating a large temperature gradient or “hot spot” that may result in tissue necrosis rather than injury. Due to thermal conduction, the extent of the thermal effect in tissue from this treatment design is much deeper than optical penetration depth alone. Muscle and fascia, water-rich tissue, have a higher heat capacity than adipose tissue; therefore, the rise in temperature and potential injury is drastically less than in fat. The 1060 nm wavelength also has a low affinity for melanin allowing treatment of darker skin types, i.e., Fitzpatrick skin types V–VI, possible.

3.4 Tissue Response To Laser Treatment

Immediately after treatment, an inflammatory response is initiated. Ultrasound imaging of the treatment zone demonstrates evidence of an immediate inflammatory response with the appearance of a “cloud” (▶Fig. 3.1). Within one week of treatment the response appears uniformly through the entire treatment area. Histological examination of the treatment area demonstrates lymphocyte infiltration within 2 weeks followed by invasion of macrophages resulting in phagocytosis of injured adipocytes with vacuole formation. By 2–3 months after treatment, macrophages surround the adipocytes with significant reduction in adipose tissue volume (▶Fig. 3.2). ⁶

3.5 Patient Selection

The SculpSure device is engineered to treat localized subcutaneous fat deposits. Establishing realistic expectations of the treatment is essential to patient satisfaction. The ideal candidate has a BMI of <30, and has “pinchable” subcutaneous fat. Visceral fat will not be adequately treated. Evaluation for treatment with SculpSure is similar to the evaluation prior to Liposuction. Standardized pre- and posttreatment photography is essential documentation for evaluation of treatment results. Although current FDA approval is for treatment of the abdomen, flanks, back, submental area and inner and outer thighs, off-label treatments include upper arms, calves, the suprapatellar region, “bra” fat and gynecomastia.

3.6 Technique

After marking the desired treatment area, laser array cradles are placed over the treatment site to permit maximum coverage of the region (▶Fig. 3.3). The laser cradles are secured in position using the adjustable belt system. Adequate “pillowing of the fat” into the laser cradle will ensure proper contact of the laser array with the tissue to be treated (see ▶Fig. 3.3). Lux lotion is applied to the skin to provide uniform contact between the skin and the laser window. The laser array has a water-cooled sapphire window at the point of skin contact. Surface cooling provides additional patient comfort to the sensory nerve-rich skin during treatment as well as protection against superficial thermal injury.

SculpSure supplies 4 independent flat panels, non-suction laser arrays for placement into the cradle system. Independent power control for each array allows for tailoring the treatment to patient comfort and desired improvement. The laser array snaps into the cradle with an audible click. Once in proper position, a visible indicator light turns green allowing treatment to commence (▶Fig. 3.4). If the array is not in proper contact with the treatment area, the treatment will abort. No laser safety eye protection is required as the laser will not function unless the proper contact between the laser array and the treatment area is established and maintained.

The laser was designed to create a smooth or even temperature gradient throughout the treatment zone resulting in a large volume of subcutaneous tissue heated to the therapeutic temperature range of 42–47°C. The maximum tolerable tissue temperature is limited by patient discomfort. Although power adjustability is possible, from 0.9–1.4 J/cm ² , high power settings are not mandatory to obtain the desired clinical effect. If the subcutaneous tissue temperature reaches our goal of >42°C and <48°C, clinically visible reduction in subcutaneous adipose tissue will occur over the ensuing months without evidence of tissue necrosis. ⁶

The treatment is 25 minutes in length in 2 phases. The initial 4 minutes of the treatment is the “build” phase. This is preset to a power setting of 1.1 J/cm ² although power setting adjustment is possible. During this period, laser energy is applied to the treatment zone to rapidly raise subcutaneous adipose tissue to the desired temperature range of 42–47°C. The 21-minute “sustain” phase of treatment involves the intermittent cycling of the laser on and off (laser duty cycle) to maintain the goal temperature range. ⁶ Adjustment in the power setting can be performed to the clinical endpoint of perceived heat within the treatment zone. Maximum power settings are not required to obtain clinical results from the treatment. This may result in patient discomfort limiting the tolerability of the treatment.

Following completion of the treatment, the laser arrays are removed from the cradles and cleaned. The cradle and belt system are removed. Little to no alteration in skin appearance is noted. The patient may resume normal activity. The use of compression garments is not necessary. Massage of the site may be of some benefit as tissue edema and temporary nodularity (fat edema) may be noted. If present, resolution of nodularity occurs within 2–3 months. Prolonged (>6 months) nodularity, while rare, may occur and is indicative of overtreatment with peak tissue temperature above 48°C. The treatments are very well tolerated without the need for pain medication. Side effects include, tenderness, swollen and mild discomfort that usually resolve within 2 weeks of treatment.