Cryolipolysis: The Cold War Against Fat
Thursday, July 15, 2010
With the rising demand for body contouring, non-invasive
mechanisms for fat reduction have become increasing popular.
Cryolipolysis is a novel technology using controlled cold exposure,
which selectively reduces subcutaneous fat. The technology is based
on the concept of "popsicle panniculitis", or cold-induced
inflammation of adipose tissue and resulting fat loss. By
controlling and modulating the cold exposure, it is possible to
selectively damage adipocytes, while avoiding damage to the
overlying epidermis and dermis. The decrease in fat thickness
occurs gradually over the subsequent 3 months, and it is most
pronounced in patients with limited, discrete fatty bulges.
Mechanism of Action
The exact mechanism of cryolipolysis remains unknown. Adipocytes
appear to be more susceptible than skin cells to necrosis after
exposure to cold. The initial reports of infants suffering from
cold panniculitis and adults with equestrian panniculitis
demonstrate a perivascular inflammatory infiltrate consisting of
histiocytes and lymphocytes, developing approximately 24 hours
after cold exposure. This inflammatory infiltrate subsequently
progresses to a lobular panniculitis, with resolution over several
weeks, and ultimately results in fat resorption without persistent
tissue damage or scarring.1,2
The use of cryolipolysis for fat reduction shows similar
histologic findings. Immediately after treatment, adipocytes are
intact and there is no apparent fat damage. Within 3 days of
treatment, there is evidence of adipocyte apoptosis with an influx
of inflammatory cells.3 At approximately 14 days, the
inflammation peaks and, between 14 and 30 days after treatment,
lipid phagocytosis becomes apparent. The adipocytes become smaller
and irregularly shaped as they are slowly digested by macrophages.
After this period, the inflammatory response subsides and the
volume of fat cells decreases, with apparent thickening or
condensation of the interlobular septae occurring by 60 days. The
inflammatory process declines further by day 90 post-treatment.
Cryolipolysis studies conducted on Yucatan pigs demonstrated
significant fat reduction using a prototype device, without any
change in the serum lipid levels.4 The Zeltiq System
(Zeltiq Aesthetics Inc, Pleasanton, CA) was developed subsequent to
these animal studies, with similar predictable results. This device
consists of a control console, with a treatment applicator attached
by a cable. A thermal coupling gel sheet is placed on the area to
be treated, and the applicator is then applied. The target tissue
is drawn into the cup-shaped applicator with a moderate vacuum to
position the tissue optimally between two cooling panels. A cooling
intensity factor (CIF) is then selected by the treating clinician.
The CIF is an index value representing the rate of heat flux into
or out of tissue opposite the cooling device. The cold exposure
treatment is generally 60 minutes per area. The energy extraction
rate, or cooling, is controlled by sensors that monitor the heat
flux out of the treated areas and is modulated by thermoelectric
cooling cells. Following completion of the treatment cycle, the
vacuum is released and the device is transferred to the next area
to be treated.
Given that the applicator is only able to chill a relatively
small area at any one time, multiple applications may be necessary
to effectively expose the entire area to cryolipolysis. For
instance, it might take two or three applications per session to
treat the abdomen, and four applications to treat both "love
handles". Review at 2-3 months indicates good or very good fat
reduction in about 70% of cases when appropriate patient selection
is made (Figures 1 and 2). Ultrasound examination both pre- and
post-treatment indicates that approximately 100% of patients
respond. However, in our opinion, it is the patient's perception of
improvement that is the most important consideration. Thus, patient
expectations must be reasonable. It is important to note that the
Zeltiq device is presently FDA-indicated for skin cooling and
surface anesthesia, and that use of the Zeltiq device for
cryolipolysis is currently off-label.
Figure 1. Prior to treatment. (Photograph
courtesy of Christopher Zachary, FRCP)
Figure 2. 3 months post-treatment. (Photograph
courtesy of Christopher Zachary, FRCP)
The known risks of the procedure include relatively modest
discomfort during the procedure, temporary erythema of the skin,
transient bruising, and a dysaesthesia at the treatment site, which
generally disappears within a few weeks. Coleman et al.
reported that there are no long-term sensory effects and, to date,
there have been no reports of scarring, ulceration, or alterations
in blood lipid or liver function profiles.5,6 However,
we have noted that two patients have reported "severe pain"
following this treatment: one case in Southern California, and the
other in Ottawa. These were both self-limiting, but lasted for
several weeks. In at least one of these cases, the patient had an
Cryolipolysis is a novel procedure, which uses controlled cold
exposure to produce non-invasive, essentially painless and
predictable adipocyte loss. In animal and human clinical studies,
cryolipolysis has been shown to result in significant improvement
in the clinical appearance of localized fatty deposits. The current
data support the concept that cryolipolysis is most effective for
localized, discrete fatty bulges. The patients who desire
large-scale fat removal should rely on weight reduction with
exercise and diet, although localized fat loss may still be
achieved in some of these cases with cryolipolysis. The treatment
is particularly appealing given that it is not associated with any
downtime, and it does not require local or regional anesthesia.
Overall, cryolipolysis appears to be a promising new technology for
safe, effective, and non-invasive treatment of fat.
- Epstein EH Jr, Oren ME. Popsicle panniculitis. N Engl J
- Nelson AA, Wasserman D, Avram MM. Cryolipolysis for reduction
of excess adipose tissue. Semin Cutan Med Surg
- Avram MM, Harry RS. Cryolipolysis for subcutaneous fat layer
reduction. Lasers Surg Med 2009;41:703-708.
- Zelickson B, Egbert BM, Preciado J, et al.
Cryolipolysis for noninvasive fat cell destruction: initial results
from a pig model. Dermatol Surg 2009;35:1462-1470.
- Klein KB, Zelickson B, Riopelle JG, et al.
Non-invasive cryolipolysis for subcutaneous fat reduction does not
affect serum lipid levels or liver function tests. Lasers Surg
- Coleman SR, Sachdeva K, Egbert BM, Preciado J, Allison J.
Clinical efficacy of non-invasive cryolipolysis and its effects on
peripheral nerves. Aesthetic Plast Surg