Traditional liposuction remains the gold standard for fat removal. Laser liposuction has recently been developed but still remains an invasive procedure, and it is unclear if laser lipolysis offers any significant advantage over traditional liposuction. The demand for alternatives to invasive lipolysis is great, and a variety of approaches have been developed for non-invasive lipolysis (Table I). In the United States, the majority of these devices are investigational or being used off-label for non-invasive fat reduction.

Radiofrequency
Radiofrequency devices are primarily used for noninvasive skin tightening. Early observations of subcutaneous atrophy have led the development of these devices for body contouring with the potential of subtle changes in the subcutaneous tissue. Radiofrequency produces a thermal effect in the tissue by creating volumetric heating. Coincidental improvement in cellulite may be noticed due to the lipolysis in the superficial subcutaneous fat. The gold standard of radiofrequency devices is unipolar radiofrequency (Thermage) with the longest clinical experience and largest peer reviewed studies. The introduction of a large body tip with Thermage has allowed for the more efficient treatment of large body areas, such as the abdomen. Other approaches use unipolar and bipolar radiofrequency (Alma), bipolar radiofrequency (Velasmooth), and bipolar radiofrequency with vacuum (Aluma)

Non-Invasive Lasers
Selective photothermal excitation of fat has been noted at 1210nm and 1720nm. Low level energy at 635nm has been reported to cause radiolysis. Commercial examples of lasers include the 650 and 915nm laser (Smooth Shapes) in combination with massage, 635nm diode laser (Echoing Medical) and a 630-680nm laser (Lipolaser). The true clinical effects of some of these low energy lasers for fat reduction as a standalone device are unclear, as some require diet and exercise along with low level laser therapy.

Cryolipolysis
Non-invasive controlled cooling of fat cells can produce lipolysis. The proposed mechanism is the creation of fat cell apoptosis by exposure to precise controlled cooling. Inflammatory cells gradually eliminate the affected fat cells, producing a reduction in the thickness of the fat layer. Selective cryoliploysis is the first commercial device (Zeltiq) with clinical trials showing fat layer reduction up to 1cm after a single treatment. The device is being used off-label in the US and is approved in Europe, Canada and several Asian countries for non-invasive lipolysis. We have used the device for approximately four months. Patient selection is key, and the device is best suited for those who have isolated areas of fat but are generally in good shape. Results are most evident following two months after the initial treatment. The role of multiple treatments is currently being evaluated. The main advantage of this treatment is the lack of discomfort and return to normal activity after treatment with no downtime. Patients have reported numbness in the area treated up to one month and areas of ecchymoses which resolve within a few days.

Ultrasound
Thermal coagulation producing adipocyte apoptosis is the mechanism by which ultrasound creates lipolysis. Commercial devices include Ultrashape and Liposonix. The Ultrashape device requires multiple treatments and can show reduction of 2 to 6cm after a series of treatments without reported discomfort. The Liposonix device utilizes high intensity focused ultrasound and after a single treatment may show up to a 2.8cm reduction in circumference. Pain control is an issue with this device. Both devices are investigational in the US but approved in Canada, Europe and certain Asian countries for lipolysis.

Conclusions
A variety of devices are being evaluated for non-invasive fat reduction. The majority of these devices are being used off label in the US for non-invasive fat reduction. Large and long-term clinical studies are still in their infancy. Our experience has been limited with the use of a device that employs cryolipolysis but early results are quite promising. Over the next few years, as these devices become utilized more widely, we will truly understand their role in lipolysis. Until then, traditional liposuction still remains the gold standard for fat reduction.

Dr. Narurkar has no relevant disclosures.