DANA POINT, CALIF. – Practice skepticism when it comes to the efficacy of noninvasive fat removal devices, advised Dr. Matthew A. Avram.
"Fat removal has a long history of 'snake oil' salesmanship," Dr. Avram said at the Summit in Aesthetic Medicine, which was sponsored by Skin Disease Education Foundation (SDEF). "You can count on this to continue, because many of these devices do little, if anything. It is important to critically assess these technologies in this emerging field."
Dr. Avram, faculty director for procedural dermatology training at Harvard Medical School and director of the dermatology laser and cosmetic center at Massachusetts General Hospital, both in Boston, discussed the evidence surrounding devices for noninvasive fat reduction.
One non–Food and Drug Administration–cleared modality being studied is focused ultrasound, which delivers mechanical, nonthermal energy to the thigh, abdomen, and flanks. A study of 30 patients who were treated once a month for 3 months demonstrated a circumference reduction of 2-4 cm in the treated sites (Lasers Surg. Med. 2007;39:315-23). Liver function tests, a lipid panel, and liver ultrasound showed no adverse systemic effects from the procedure.
However, Dr. Avram noted that the study is limited because there was no untreated control group and that circumference "is an inherently imprecise measure of improvement that can be manipulated." MRI would prove objective improvement, he said, but it was not performed in this trial.
In a subsequent study from Hong Kong, 53 patients underwent treatment once a month for 3 months for body contouring (Lasers Surg. Med. 2009; 41:751-9). No significant changes were observed in circumference and caliper measurements, and patients rated their satisfaction as poor.
High-Intensity Focused Ultrasound
High-intensity focused ultrasound, which is also not FDA cleared, involves the rapid heating of adipocytes that are purported to produce coagulative necrosis and cell death in adipose tissue. A retrospective chart review of the modality that was used in 85 patients who underwent one treatment session showed a mean 4.6 cm decrease in waist circumference after 3 months (Aesth. Plast. Surg. 2010;34:577-82). Adverse events that lasted 4-12 weeks occurred in 12% of subjects and included prolonged tenderness, ecchymosis, nodules, and edema, as well as procedural pain in one patient, which required discontinuation of the procedure.
Dr. Avram called high-intensity focused ultrasound a promising technology, "but it's difficult to assess its efficacy. Further study of this technology is needed."
Monopolar radiofrequency, conventionally used for tissue tightening of the face, has produced lipoatrophy with aggressive settings as a complication. "Perhaps this can be harnessed to effectively treat fat," he said, noting that clinical studies are currently underway.
Low-Level Light Therapy
Low-level light therapy, an FDA-cleared modality for fat removal, uses a multiple head, low-level diode laser at an energy level of 635 nm, which is "roughly equivalent to a laser pointer," Dr. Avram said. In one randomized trial, 59 patients received three treatments of the technology or sham treatment per week for 2 weeks (Lasers Surg. Med. 2009;41:799-809). At 2 weeks, mean circumference reductions in the treatment group were 0.98 inches at the waist, 1.05 inches at the hip, and 0.85 inches at the right thigh and 0.65 inches at the left thigh. Circumference increased in the 2 weeks following treatment.
Dr. Avram said the study was poorly designed because there was no untreated control group, the duration of treatment was only 2 weeks, and there was no ultrasound or other noninvasive evidence of decreased fat layer. "Treat with extreme skepticism," he advised.
Perhaps the most promising technology is cryolipolysis, he said, which is FDA cleared for noninvasive fat removal. Cryolipolysis involves the noninvasive cooling of fat to selectively cause cell death without damage to surrounding tissue.
The mechanism of action of cryolipolysis is believed to involve selective crystallization of lipids in fat cells at temperatures near freezing. "Apoptotic fat cell death is followed by slow dissolution of the fat cell and a gradual release of lipids," Dr. Avram explained. "The inflammatory process results in fat layer reduction over 2-4 months."
When human studies of the technology were first conducted in 2008, enrollment was restricted to 32 patients whose "love handles" were treated at a cooling intensity factor (CIF) of 33 for 60 minutes, and progressed to higher rates of energy extractions for 45 minutes per application site. One side was treated; the untreated contralateral side served as the control.
Efficacy was evaluated at 4 months post treatment via visual assessment as a primary end point, as well as ultrasound and histology. The ultrasound results demonstrated an average 23% decrease in fat layer thickness.
"In this initial group of 32 love handle patients treated once, discernible changes were seen on the treated side vs. baseline of the treated side, and compared to the untreated contralateral control," Dr. Avram said of the findings presented during a poster session at the 2008 annual meeting of the American Society for Dermatologic Surgery. "This unique study design [using each patient as his or her own control], provided very powerful evidence that this was a true treatment effect rather than a change in the patient's diet or exercise pattern during the 4 months after this single procedure exposure."
Common effects after cryolipolysis include redness, which lasts minutes to a few hours; bruising, which may last for a few weeks; and temporary dulling of sensation in the treated area, which typically resolves in 1-8 weeks. No postprocedural changes in pigmentation or laboratory abnormalities have been observed, he said.
About 1 in 2,000 patients experiences severe pain beginning 3-7 days post treatment, which translates into 26 reported cases out of 60,000 treatments. "We are not sure why these occur, but these cases completely resolve with no sequelae," Dr. Avram said.
He emphasized that cryolipolysis is not a replacement for liposuction. "It is not a weight-loss device," he said. "It's best suited for local fat removal resistant to exercise in relatively fit patients."
Dr. Avram disclosed holding stock options in Zeltiq Aesthetics, which manufactures cryolipolysis equipment.