Biomedical Engineering Reference
In-Depth Information
study was due to the induction of dermal fi broplasias (32).
Although studies have revealed a good safety profi le with
unipolar RF, there is a general lack of consensus regarding the
effi cacy in the improvement of the clinical appearance of
cellulite (31,32).
temporal or cheek regions, where there possibly has been fat
atrophy because of the elevated energy levels and single-pass
protocols once used.
No studies have been published on the use of the older
Thermacool Thermage system or CPT system for the treat-
ment of cellulite and/or subcutaneous tissues of the buttocks
and thighs.
Thermage
Thermage (Solta Medical, Inc., Hayward, California, USA)
delivers monopolar RF through a cooled epidermis and
superfi cial dermis to the deeper dermis, creating thermal
damage. It is proposed that the remodeling of deep dermal
collagen (fi brous septa) allows modeling of contours and
improvement of cellulite appearance in a single treatment.
Thermage has FDA clearance for the noninvasive treatment of
wrinkles and rhytides, as well as temporary improvement in
the appearance of cellulite when used with vibration. The new
Comfort Pulsed Technology (CPT) enables energy delivery in
short, rapid pulses at varying energy levels, which patients
fi nd tolerable. The depth of penetration of the RF, the depth
of damage, and hence remodeling depend on the type of tip
used in the machine and the energy delivered by the machine
through the tip.
The device has three main components: a generator, a
cryogen unit, and a hand piece with a treatment tip. The gen-
erator supplies the RF and monitors through a display unit
the output current, output energy, number of treatments,
duration of treatment, and impedance (35,38). The Ther-
mage Cellulite Tip 3.0 (CL) is utilized for cellulite treatments
(36). Prior to initiation of treatment, a return pad is applied
to the patient, allowing the generator to supply the monopo-
lar RF in a closed circuit between the device and the patient.
A temporary marking grid is applied so that the operator can
place the treatment tip accurately for each pulse. Coupling
lubricant is then applied. Before beginning the treatment, the
patient's individual impedance is automatically measured by
the system (35,38). Treatment levels typically employed range
from 372.5 to 374. The operator delivers two staggered con-
secutive passes to the full treatment area, and the remaining
treatment passes are used at the providers' discretion on vec-
tors needing greater skin contouring. In general, energy levels
between 27 and 44 J/cm
2
are used with an average of 900
pulses when the area above the knee or small thigh areas are
treated bilaterally. Larger thigh areas and upper thigh and
buttocks may need two to three staggered passes plus vectors,
requiring up to 1800 total pulses between two sides. It is esti-
mated that the device heats tissue to 65-75°C, the critical
temperature at which collagen denaturation occurs (36-38).
The device has a feedback mechanism to alert the user if
maximum temperatures have been reached in a particular
area, so that the area is avoided. It also features a feedback
system to notify the user if there is insuffi cient contact with
the skin. The lateral aspects of the abdomen, inner thighs,
and under arms are sensitive sites (35,38).
No further treatments are advisable within 6 months. Treat-
ment may be repeated yearly. In addition to the adverse events
associated with unipolar RF treatments, mentioned above,
inconsistent results, blistering, scarring, development of tem-
porary nodules and swellings, and contour irregularities have
been reported with the older machines, particularly over the
Exilis
Exilis (BTL Industries, Inc., Prague, Czech Republic), a device
combines monopolar RF and ultrasonic energy, was intro-
duced to the market with FDA clearance for the noninvasive
treatment of wrinkles and rhytides in 2009. Animal studies in
porcine tissue have demonstrated that a penetration depth of
30 mm is safely obtainable. The Exilis body treatment head has
a cooling tip, constant temperature monitoring of the skin sur-
face via an integrated IR thermometer, and adjustable RF (W)
energy control. Peak monopolar RF energy and ultrasonic
energy are 120 W and 3 W/cm
2
, respectively. The integrated
“Energy Flow Control System” eliminates peaks of RF energy.
A unique feature of this device, as compared with other
RF devices, is the sensor monitors for constant contact between
the skin surface and the applicator. If the treatment head is
removed from the skin surface during treatment, arcing, pain,
blistering, or a burn will not result (39).
Anecdotally, this device has been used off-label for improve-
ment in the appearance of cellulite; however, randomized clini-
cal trials are lacking. For the treatment of cellulite, the treatment
area is divided into 20 cm × 10 cm sections. The grounding elec-
trode is placed adjacent to the zone of treatment and mineral oil
is applied to the skin surface within the gridded area. The cool-
ing tip is adjusted to 10°C and the treatment head is moved con-
tinuously in a circular array within the 200 cm
2
grid. Fifty watts
is the recommended starting RF energy and should be increased
over 1 minute until a surface temperature of 40-41°C is reached.
Once attainment of the targeted temperature end point, treat-
ment is continued for an additional 3 minutes to maintain the
skin surface at 40-41°C while the RF energy is simultaneously
decreased. The average treatment time per grid is 6 minutes,
with a total treatment time of 30 minutes per session. Treat-
ments are administered weekly for 3-4 weeks. For the following
48 hours after treatment, the patient is encouraged to increase
their fl uid intake, which enhances treatment effi cacy by allow-
ing degraded adipose tissue by products to be eliminated (Exilis
User Manual, 2009). Further studies are necessitated to investi-
gate the effects of Exilis on the appearance of cellulite.
TriPollar
TriPollar (Pollogen Ltd., Tel Aviv, Israel) combined three RF
electrodes to deliver low-level (5-30 W) RF energy into the
dermis and subcutaneous tissues at a depth of up to 20 mm to
produce volumetric heating for immediate collagen contrac-
tion and neocollagenesis. The depth of heating is roughly
equivalent to the mean difference between the spacing of the
RF electrodes. The polarity of the three electrodes is in con-
stant, alternating rotation between all electrodes (i.e., all elec-
trodes have the capability to act as positive or negative, although
one is always positive and two are negative), to avoid overheat-
ing of the positive electrode. Cutaneous cooling is not required
