"Marketing data for the period between June 2009 and December 2010 indicate that over 40,000 cases were performed on a commercial basis in the United States. While results of clinical trials supported the safety of cryolipolysis, increasing popularity of this treatment in commercial use allows identification of rare adverse events," says Dr. Saedi, dermatology resident, University of California, Irvine, and incoming fellow, SkinCare Physicians, Chestnut Hill, Mass."Our study confirms that cryolipolysis is generally associated with only mild, transient side effects. However, postmarketing surveillance should continue to detect and further evaluate rare and more serious adverse events," she says.
Jeffrey Dover, M.D., in private practice at SkinCare Physicians, was a co-author of the study and a clinical investigator in premarketing clinical trials for one cryolipolysis platform (CoolSculpt, Zeltiq). "In our own extensive clinical use of the device since FDA (Food and Drug Administration) approval, we have found the CoolSculpt procedure to be a highly safe and effective treatment for the reduction of localized areas of fat, such as the in the abdomen and love handles," Dr. Dover says.
RARE EVENTS The data received from the device manufacturers included 23 reports of severe pain, representing an estimated incidence of about 0.05 percent. Terms used to describe the pain included severe, shooting, jabbing, extreme sensitivity to touch and deep or severe burning.
Information on treatment site and applicator type was available for 22 of the reports. The abdomen was the involved treatment site in 21 cases, and a large applicator was used in 12 of the cases.
Time to onset of severe pain varied from one to seven days with a mean of 3.4 days. About one-fourth of the patients reported the pain worsened over time, and while the mean time to resolution was almost 14 days, pain persisted beyond 14 days in 70 percent of patients. Time to resolution ranged from seven to 28 days.
"The exact etiology for severe pain is not known, but there are several possible explanations. Selective reduction of subcutaneous fat with cryolipolysis is based on the concept of 'Popsicle panniculitis,' and the severe pain may be due to an exaggerated panniculitis or have a focal neuropathic origin due to allodynia hyperneuralgia or nerve inflammation," Dr. Saedi says.
Various treatment methods were used to alleviate the pain. None appeared consistently effective, although topical lidocaine using either a patch or cream formulation was somewhat beneficial.
The review of manufacturer's data also identified four reports of hyperpigmentation (<0.01 percent), all of which resolved within two to four months. The cases were associated with first- or second-degree burns from freezing of the dermis, and operator error was noted in three of the events.
Dr. Saedi also reviewed data from two premarketing clinical trials of cryolipolysis. One published report used a prototype device of a commercially available platform (CoolSculpt) and evaluated postcryolipolysis sensory changes by neurologic evaluation in nine patients and biopsy in the 10th (Coleman SR, Sachdeva K, Egbert BM, et al. Aesthetic Plast Surg. 2009;33(4):482-488). Six patients were found to have transient localized sensory loss based on neurologic evaluation. Histological findings were normal in the patient who had nerve biopsy. All patients had return of normal sensation after a mean of 3.6 weeks.
In an unpublished report relating to the same platform, Burns et al summarized data from two multicenter clinical studies that enrolled 341 patients treated at 16 clinical centers. Treatment sites included love handles or back fat, and side effects were investigated in a systematic manner at serial clinical follow-up visits and using phone interviews. Duration of follow-up was 16 weeks in one study and 26 weeks in the second.
Common side effects documented immediately after the procedure included erythema (98 percent), edema (51 percent) and bruising (45 percent); transient blanching was reported less often (8 percent).
After one week, 39 percent of patients reported numbness and tingling, while erythema, edema and bruising had resolved in most patients (incidence rates 1 to 6 percent). At eight weeks of follow-up, the only persistent side effect was mild numbness or tingling, which was present in 6 percent of patients. In the study with six months of follow-up, no patients had persistent symptoms at their last visit.
Disclosures: Dr. Dover receives research grants from and serves on the scientific advisory board for Zeltiq. Dr. Saedi reports no relevant financial interests.