2. 250 Adv Ther (2012) 29(3):249-266.
makes an additional contribution to the RF Heat generation by RF energy operates by
energy penetration. The heating effect of RF transfer of energy from the electric field to
was also found to increase blood circulation the charged particles in the target tissue. This
and to induce collagen remodeling. The results transfer can be achieved by three mechanisms
from the cellulite and body shaping treatments of interaction between the electromagnetic
showed an overall average improvement of field and the charges: (i) orientation of electric
55% in the appearance of cellulite, with an dipoles that already exist in the atoms and
average circumferential reduction of 3.31 cm molecules in the tissue; (ii) polarization of atoms
in the buttocks, 2.94 cm in the thighs, and and molecules to produce dipole moments; and
2.14 cm in the abdomen. The results from the (iii) displacement of conduction electrons and
skin tightening procedure showed moderate ions in the tissue [2]. In the first and second
improvement of skin appearance in 50% mechanisms, the heat is generated by the
and significant improvement in 31%. At the energy use involved in the movement of the
follow-up visits the results were found to be particles in response to an electric field. In the
sustained without any significant side effects. third mechanism, heat is generated by collisions
Conclusion: Of all tissue heating techniques, between the transmission charges and immobile
RF-based technologies appear to be the most particles. Heat is generated in tissue by both the
established and clinically proven. The design incident electric and the magnetic field. Since
and specifications of the described vacuum- the magnetic field does not transfer any net
assisted bipolar RF device fall within the range energy it does not produce any heat [1].
of the specifications currently prescribed for Therefore, the mechanism of tissue heating
esthetic, nonablative RF systems. by electrical current is based on generating
joules of heat. Generated heat is described by
Keywords: Body contouring; Cellulite; Joule’s law:
Radiofrequency; Radiofrequency energy; Skin
j2
tightening; Vacuum H= ,
σ
INTRODUCTION
where j is the density of electrical current
Physics of RF Energy and σ is electrical conductivity [3]. The
opposite of conductivity is called resistance
Radiofrequency (RF) energy is a type of or impedance (R). The parts of the body with
electromagnetic wave which is exponentially high blood content have the highest electrical
attenuated during transition into the target tissue. conductivity. Bone, for example, has very
At high frequencies of electromagnetic wave, low electrical conductivity, and consequently
power is transferred rapidly close to the surface, the electrical current flows around it without
attenuating the wave as it is dispersed. At lower penetration. Dry skin also has very low electrical
frequencies, in the spectrum of RF for example, conductivity and must therefore be hydrated to
because the wavelength is greater and therefore enhance the passage of the current [1].
the heating cannot be localized to limited areas, In general, the electrical conductivity
the energy penetration is deeper. For this reason, influences the depth to which RF energy
the term “bulk” tissue heating is used [1]. penetrates. The RF energy penetration
3. Adv Ther (2012) 29(3):249-266. 251
depth equation consists of π constant, the positively charged grounded electrode. The
electromagnetic wave frequency (the test active electrode has a relatively small contact
frequency), the magnetic permeability of the point with the skin, while the ground electrode,
tissue, and the tissue’s electrical conductivity, as which is larger in size, is applied to the body
follows: at a distance from the active electrode. The
electrical energy is concentrated near the tip of
1
δ≈ the active electrode and decreases rapidly with
√πfµσ
distance. The calculation of assessed penetration
depth of RF energy is that it is half the size of
where δ is the standard depth of penetration the active electrode: for example, a 10-mm
(mm), π is 3.14, f is the test frequency (Hz), unipolar electrode can penetrate to a depth of
μ is magnetic permeability (H/mm), and approximately 5 mm.
σ is electrical conductivity (% International The ability of the monopolar configuration
Annealed Copper Standard, IACS). to create a high power density on the surface of
From this equation it can be determined the electrode makes it popular in electrosurgery.
that the depth of penetration of RF energy in In this type of procedure a small-sized electrode
millimeters is inversely proportional to the is usually used. However, the unpredictable
square root of the frequency. Therefore, lower behavior of a unipolar system, as the current
frequencies have higher penetration rates and passes through the body to the grounding
vice versa. The ability to control heating depth is electrode, is a disadvantage in cosmetic
particularly desirable in a system that is designed procedures [1].
to treat both body and facial areas.
Bipolar System
Types of RF Configuration A bipolar configuration also carries energy via
two negative (cathode) and positive (anode)
Electrical conductivity depends on several electrodes but with a fixed distance, while both
parameters, including tissue type, the frequency electrodes are in contact to the skin. This way
of the electrical current, and tissue temperature. the RF’s electrical current propagation is limited
The distribution of electrical current, on the other by the area between electrodes. The calculation
hand, depends on the geometry of the electrodes. of assessed penetration depth of RF energy in a
In medicine there are two typical RF bipolar system is half the distance between the
configurations that are used: the monopolar and electrodes. For example, in a bipolar system with
the bipolar. The main difference between them a 4-mm distance between two electrodes, the
is the way in which the current is controlled theoretical depth is approximately 2 mm.
and directed to the body. However, at the same In contrast to the monopolar configuration,
energy fluence there is no difference in the tissue the main advantage of a bipolar configuration
effect [1]. is that the RF current inside the tissue has
a controlled distribution that is limited by
Monopolar System the volume between the two electrodes.
A monopolar configuration carries energy Consequently, the bipolar system is less
via two electrodes: one negatively charged appropriate for electrosurgery, but it s more
cylindrical active electrode and a second suitable for homeostasis and controlled vessel
4. 252 Adv Ther (2012) 29(3):249-266.
contraction [1]. Moreover, since bipolar energy is Initial reports of a nonablative RF system
more localized, less energy is required to achieve describe bipolar RF energy used for collagen
the same heating effect as with the monopolar shrinkage in shoulder instability. This system
configuration [4]. (CAPSure; Arthrocare Corp., Austin, TX,
USA) [8] was used to thermally tighten the
Multipolar System shoulder capsule and glenohumeral ligaments.
In the esthetic market there are also “new” types Shortly following these reports, a nonablative
of RF energy, including multiple monopolar, commercial RF device was reported. This
tripolar, octapolar, etc., configurations. monopolar RF system, indicated for facial skin
Basically, there are only monopolar or bipolar tightening, requires a cryogen spray to cool the
RF electrodes. The multiple monopolar is active electrode in order to preserve the skin
based on two monopolar electrodes (negative) surface from thermal damage. In July 2000
and one ground electrode (positive). The this system received its first US Food and Drug
tripolar configuration, is a combination of Administration (FDA) clearance for indications
one monopolar and one bipolar electrode or a which have since been extended to include
combination of one negative and two positive “noninvasive treatment of wrinkles and rhytids”
electrodes (which creates two pairs of a bipolar as well as “temporary improvement in the
system). The octapolar is a system that comprises appearance of cellulite” [9].
four pairs of bipolar electrodes. Following the introduction of this system,
several other monopolar and bipolar nonablative,
History of RF Energy Applications esthetic RF systems have been cleared by the FDA.
While some of these systems are RF-only systems,
Electrical current has been used in medicine for others combine RF with various other treatment
more than a century [4]. RF energy has been modalities such as infrared light, vacuum, and
used in medical treatment for over 75 years [5], mechanical massage. The FDA-cleared indications
generally for minimally invasive surgical for these combination systems range from
procedures using RF for ablation and coagulation, temporary improvement of blood circulation to
including in the treatment of sleep apnea [6]. temporary reduction of thigh circumference [10].
The high efficiency of RF current for tissue
heating has also made it useful for electrosurgery Indications and Contraindications for RF
and an attractive source of energy for various Energy-Based Treatment
dermatologic applications [7]. However, the
technology is not solely limited to these fields. A RF current produces a pure thermal effect on
In fact, most devices used on a daily basis operate biological tissue. An assembly of technologies
on a RF basis, such as radio, TV broadcasting, falls under the heading of noninvasive body
wireless internet and phones, point-to-point shaping. RF energy, which is safe for all skin
links, microwaves, satellite communication, and types, is fairly new, but a number of firms have
so on. Although the energy utilized is the same successful RF devices on the market [4].
(RF energy), the difference in applications comes The degree of heat-induced tissue shrinkage
from the different frequencies employed. For is dependent on several factors, which include
medical and esthetic applications a RF frequency the maximum temperature reached, the heat
of up to about 10 MHz is normally used. exposure time, tissue hydration, and tissue age.
5. Adv Ther (2012) 29(3):249-266. 253
Skin Tightening blood flow in the adipose tissue [13], which
RF as a source of heat has been used for collagen in turn increases the metabolism of the tissue,
denaturation which leads to shrinking of homogenizing subdermal fat and increasing skin
redundant or lax connective tissue. Collagen elasticity. This results in an improvement in skin
molecules are produced by fibroblasts cells in texture. Moreover, Franco et al. in their in-vivo
the dermis. The collagen protein is a compound experiments showed that 10 minutes of thermal
of three polypeptide chains that wrap around exposure at 43°C resulted in a delayed adipocyte
one another in a final triple helix structure. The cellular death response [1]. Galitzky et al., on
process of thermal shrinkage of collagen starts the other hand, showed in-vivo enhancement
with denaturation of the triple helix, in which of fat cell lipolysis by increased delivery of
the heat-labile intramolecular cross-links are catecholamine hormones, which is improved
broken and the collagen undergoes a transition by enhancement of blood flow [14].
from a highly organized crystalline structure to a
random, gel-like state (denaturation). The collagen Contraindications
shrinkage occurs through the cumulative effect Contraindications to the use of RF include
of the “unwinding” of the triple helix, due to pregnancy, any implanted electronic device, hip
the destruction of the heat-labile intermolecular replacement, hip or femur surgery, or any other
cross-links, and the residual tension of the metallic device that could be disrupted by RF
heat-stable intermolecular cross-links [11]. In energy, and any active dermatologic or collagen–
addition, heated fibroblasts are associated with vascular disorder. Active or recent malignancies,
new collagen synthesis and therefore tissue any history of disease which may be stimulated
remodeling. Therefore, the RF effects are based by heat, current use of isotretinoin, and
on mild heating of the collagen and elastin blood coagulopathy are all contraindications
fibers, which can lead to collagen shrinkage and for electromagnetic source treatments. Also,
dermal thickening, thus improving the firmness treatment over tattoo or permanent makeup and
and elasticity of the skin. There are many studies synthetic fillers (e.g., silicone) is not advised.
corroborating the need to reach a temperature As with any other RF-based device,
range of 39–42°C (clinically effective temperature) appropriate selection of patients and managing
in the skin for RF esthetic-related effects. Hiragami realistic expectations are key to ensuring
et al. demonstrated that treating skin for 10 min satisfaction with results.
at 43°C enhanced 3D-like proliferation of normal The main purpose of this article is to describe
human dermal fibroblasts, which consequently in detail the extensive use of existing medical
led to greater expression of new collagen [12]. devices based on RF energy, the development
of these devices over the years, differences in
Cellulite Reduction RF configurations, and present recent and novel
RF systems have been reported as producing developments and trends in this technology.
electrothermally mediated rejuvenation- As an example of the novel trends the present
related cutaneous and subcutaneous effects. It authors have chosen to describe their personal
is feasible to use RF energy for selective heating experience with CORE (Channeling Optimized
of relatively large volumes of subcutaneous RF Energy) technology, and to show the scientific
adipose tissue [1]. The heating effect leads to aspects of different stages of clinical study of the
increased microcirculation, thus increasing technology.
6. 254 Adv Ther (2012) 29(3):249-266.
METHODS allows independent heating depth control
by applying three separate RF frequencies,
Literature Review Search Strategy and Data at 0.8 MHz, 1.7 MHz, and 2.45 MHz, and
Sources an additional mode that combines all three
frequencies in a single pulse (Fig. 1). These four
The authors conducted a systematic search of different frequency modes can be independently
publications listed in Medline and PubMed. chosen with any energy and probe setting. This
Only articles published in well-known way it is possible to control the heating depth
scientific journals in the dermatologic and as required by each patient’s symptoms and for
esthetic fields were searched for. Key and each treatment application.
free-text words included “radiofrequency”
AND “skin tightening,” “radiofrequency” Device Applicators
AND “cellulite,” “radiofrequency” AND Three different treatment applicators are
“contraindications,” “radiofrequency” available with the system.
AND “indications,” “radiofrequency” AND B-Contour applicator: emits vacuum-assisted
“efficacy,” “radiofrequency” AND “safety,” pulsed RF power of 50 W with a treatment
“radiofrequency” AND “side effect,” footprint of 35×30 mm. Designed for treatment
“radiofrequency” AND “vacuum,” and of large skin areas.
“radiofrequency” AND “adverse event.” All F-Contour applicator: emits vacuum-assisted
articles revealed were reviewed by title for pulsed RF power of 8.5 W with a treatment
relevance and potential duplication. The abstract footprint of 15×10 mm. Designed for treatment
of each of the relevant articles was examined. of small or sensitive body areas.
Overall, 50 full-text articles were examined. Out ST applicator: emits pulsed RF power density of
of these publications the authors chose 26 that 130 J/cm3 with a treatment footprint of 8×8 mm.
addressed safety and efficacy issues, technical This applicator operates without vacuum
system specifications, and clinical techniques. assistance and is cooled to 6°C. It is indicated for
The search focused on clinical research studies, skin tightening on facial and body areas.
the FDA 510(k) database for clearances, and any
technical information on company web sites In-Vivo Measurement of Penetration Depths
and the clinicaltrials.org website. of Different RF Frequencies
An in-vivo study was conducted on the skin of
RF Device two approximately 6-month-old male domestic
pigs, weighing 146.5 kg and 157 kg, that were
A bipolar RF device (Reaction™; Viora Inc., Jersey under full anesthesia by inhalation of isoflurane
City, NJ, USA) combined with a mechanical (2–3%). A thermal video camera (TiR3FT; Fluke
massage technique was designed to produce Corporation, Everett, WA, USA) was used to
high-frequency electrical current in the skin determine the tissue heating depth effects
for noninvasive skin tightening, reduction of at the different RF frequencies (0.8, 1.7, and
cellulite, and elimination of fine wrinkles on 2.45 MHz). This thermal video camera enables a
various body areas such as the face, neck, arms, temperature measurement in the range of –20°C
abdomen, buttocks, and thighs. The system to 100°C with a sensitivity of 0.07°C and an
integrates unique CORE technology, which accuracy of ±2°C.
7. Adv Ther (2012) 29(3):249-266. 255
2.45 MHz
1.7 MHz
0.8 MHz
Fig. 1 Conceptual schematic representation of CORE™ technology, showing the independent heating effect created
in between two electrodes using three separate radiofrequency (RF) frequencies (0.8, 1.7, and 2.45 MHz). The lowest
frequency, 0.8 MHz, penetrates the deepest, while the highest frequency, 2.45 MHz, has the most superficial penetration
To investigate the effect of a chosen frequency thermal effect faded (approximately 2 minutes
on tissue heating depth, tests were performed after the last pulse). For comparison purposes,
with three different RF applicators. In the test the heating depth was arbitrarily defined as the
with the B-Contour and F-Contour applicators, depth at which skin tissue temperature reached
the RF and vacuum intensities were set to the 4°C above tissue baseline temperature, which
highest level (level 4) and six sequential pulses was typically approximately 28°C.
were applied. In the examination with the
ST applicator (which does not include the Cellulite and Body Shaping Treatments
vacuum mechanism), the energy level of Twenty-seven healthy women aged 24–63 years
50 J/cm3 was applied with a single pulse. with a body mass index (BMI) lower than
To investigate the effect of vacuum on tissue 29 participated in this study. The inclusion
heating depth, tests were performed with the criteria consisted of the presence of moderate
B-Contour and F-Contour applicators at each bilateral cellulite, equal to or higher than 2
frequency separately, with the RF intensity (on a 0–4 point cellulite scale), in the abdomen,
fixed at level 4 and varying only the vacuum thighs, and buttocks. Participants were not
intensity (levels 1–4), applying six sequential allowed to diet or induce any weight fluctuations
pulses. greater than 2 kg throughout the entire study
Thermal video imaging recording started period. All subjects underwent eight treatment
with the first pulse and stopped only when the sessions at 1-week intervals.
8. 256 Adv Ther (2012) 29(3):249-266.
The treatment was performed with the visit, on the basis of clinical photographic
B-Contour applicator on large skin areas and assessment, circumference measurements, and
with the F-Contour applicator on small or an assessment of participants’ satisfaction.
sensitive areas. Each treatment session lasted Three independent evaluators were asked to
about 20 minutes in accordance with protocol complete a survey to rate the cellulite grade of
guidelines. The protocol is designed in three the photographs. Circumference was measured
phases: (i) preheating, (ii) adipose tissue by the independent evaluators according
heating, and (iii) fibroblast stimulation. The to a standardized measurement method.
purpose of the preheating phase is to obtain a Additionally, the investigators were asked to
clinically effective temperature of 39–42°C, with record and immediately report any adverse or
continuous monitoring of the skin temperature unexpected effects. Participants’ satisfaction
with an infrared thermometer. This phase targets scores were obtained at each of the three
all skin layers simultaneously and therefore is monthly follow-up visits.
conducted in mode IV (a combination of all three
frequencies) with the highest RF and vacuum Skin Tightening Treatments
intensity, according to each patient’s tolerance
and test procedure. Once the clinically effective Sixteen healthy women ranging in age from
temperature is obtained, the adipose tissue 37–66 years, with moderate to severe wrinkles
heating phase starts, in which mode I (0.8 MHz) or/and lax, sagging skin, were treated using the
is employed for 10 minutes for deep tissue RF system. All of the patients underwent three
heating to address the subcutaneous layer. The treatment sessions at 3-week intervals. The
last phase is focused on the dermal fibroblasts patients who underwent facial treatment were
in order to encourage fibroblast activity and treated on both sides of the treatment area, while
produce a skin tightening effect. The fibroblast those who underwent body treatment, such as
stimulation phase is performed in mode II the abdomen and buttocks, were treated only
(1.7 MHz) for 2 minutes and mode III (2.45 MHz) on the right side of the body. Each treatment
for 2 minutes, for a total of 4 minutes. session duration lasted an average of 25 minutes.
Three of the participants dropped out of the Treatment was conducted according to the
study for personal reasons unrelated to the study. protocol for the specific treatment area. For lower
Photographs were taken in three phases: (i) at face and perioral regions, modes I and II (0.8 and
baseline, prior to the first treatment; (ii) during 1.7 MHz, respectively) were used. For forehead
the treatment course, after the fourth treatment and cheek bone areas, the most superficial
session; and (iii) at the end of the treatment frequency was used (mode III, 2.45 MHz) and
course, one week after the eighth treatment, and for body areas, mode IV was used. The RF energy
also at each of the three monthly (after 1, 2, was chosen according to individual tolerance
and 3 months) follow-up visits and 6 months and test procedure.
after the last treatment session. Circumference To monitor and evaluate final results, pictures
measurements of thighs, buttocks, and abdomen of the patients were taken in a standardized
were taken by independent evaluators and not method at the following points: at baseline,
by the treating practitioner, to avoid bias. prior to each treatment, and at 1- and 3-month
Analysis was performed at baseline, prior follow-up visits. Photographs from the second
to the fourth treatment, and at each follow-up follow-up visit were analyzed by three objective
9. Adv Ther (2012) 29(3):249-266. 257
analysts who scored the improvements compared Abraham et al. reported on a study which
to the baseline evaluation. In addition, the focused on skin tightening of the upper eyebrow.
appointed analysts compared photographs from In a follow-up visit 12 weeks after the treatment
the first and second follow-up visits to monitor there was a statistically significant increase
any significant withdrawals in results. Patients’ in mean measured vertical brow height for all
satisfaction scores were obtained after the third patients, with minimal and self-limited side
treatment session and at each follow-up visit. effects [17].
Full verbal and written informed consent Fritz et al. were the first to report on a study
was obtained from the patients in respect of the comparing multiple RF treatments to a single
relevant studies and publication. RF treatment, for mild-to-moderate laxity of the
middle and lower face. These authors concluded
RESULTS that two RF treatments produced significantly
better improvement than a single treatment,
Literature Review of RF-Based Systems although overall improvements were modest in
both groups [18].
The first RF device aimed at skin tightening In 2006, del Pino et al. reported on the effect
(SoltaMedical, Inc. [formerly Thermage], of unipolar RF (AccentTM device; Alma Lasers Ltd.,
Hayward, CA, USA) was initially studied on Caesarea, Israel) on cellulite and subcutaneous
the lower face and neck using a standard tissue of the buttocks and thighs. A volume
guinea pig model [15]. The results showed contraction of approximately 20% was achieved
that dermal heating was achieved both at the in 68% of their patients. Adverse effects included
shallow level of the papillary dermis and deep small blisters and ecchymosis, which resolved
in the subcutaneous fat layer. According to spontaneously without complications [19].
the authors, the heating of the dermal layer One year later, in 2007, Friedman and Gilead
lead to collagen denaturation and subsequent used the combination of a unipolar handpiece
thickening and shortening of collagen fibrils. for deep tissue heating and a bipolar handpiece
The increased fibroblast activity and new for superficial tissue heating. Photographic
collagen formation were observed over a period analysis showed moderate to significant
of several months. Moreover, in the treatment improvement in 69% of the patients [20].
areas where significant skin contraction was For many years a mechanical massage
observed, histological changes were noted technique with circulatory and dermotrophic
associated with new collagen formation in the properties was known to have an impact on
dermis. FDA clearance of this device was based changes in morphometric measurements in
on an institutional review board (IRB)-approved, cellulite areas, due to an improvement in
multicenter, blind clinical trial performed in lymphatic drainage leading to temporary
86 patients with periorbital wrinkles or skin reduction in edema [21]. Monteux and Lafontan
laxity who underwent a single treatment [16]. also used microdialysis technique to show that
Fifty percent of patients reported being satisfied mechanical massage has a directly enhancing
or very satisfied with the results. Most patients effect on blood microcirculation, leading to an
experienced mild to moderate pain. Common increase in lipolytic responsiveness [22].
immediate side effects included erythema (36%) This is why the “new generation” of RF-based
and edema (13.9%). systems also combines vacuum manipulations
10. 258 Adv Ther (2012) 29(3):249-266.
with RF energy. The first vacuum-assisted esthetic applications, and to devices that combine
device has been described by Gold et al. [23]. other technologies such as vacuum, ultrasound
This vacuum-assisted, RF bipolar device draws infrared light, and more. In the next section an
the skin between two parallel electrodes before additional step in this evolution is discussed,
applying the RF current. According to the describing the unique CORE technology which
authors, a significant improvement in skin enables control over the heat penetration.
appearance and texture was detected during
the treatment course, and during the period of An In-Vivo Measurement of Penetration
6 month follow-up it continued to increase. Depths of Different RF Frequencies
Montesi et al. reported clinical and histological
results using the vacuum-assisted bipolar RF For all the enquiries tested, observed heating
device for the treatment of wrinkles, skin laxity, depth was greatest with the lowest RF frequency
acne scars, and striae distensae. Three-millimeter applied (0.8 MHz) and shallowest with the
punch biopsies of untreated skin showed atrophic highest frequency applied (2.45 MHz) (Fig. 2 and
and intensely elastotic dermal collagen, whereas Table 1).
treated skin showed a decrease in collagen In-vivo experiments also showed an increase
atrophy and increase in interstitial edema, which in the presence of red blood cells and plasma
indicates better dermal trophism [24]. fluid, which provides strong evidence for
Finally, several publications have addressed increased blood circulation (Fig. 3).
the issue of safety with nonablative, RF skin In-vivo experiments on domestic pigs
tightening. For example, Weiss et al. published showed the ability of the system to create a
a retrospective analysis of efficacy and safety “remodeling” effect on connective tissue (data
in over 600 RF facial tightening treatments not shown). Eight hours after the conclusion
performed between May 2002 and June 2006. of the treatment, indications of discontinuous
The treatment algorithm evolved over this connective tissue as a result of microtrauma
period from high-fluence single treatment to created by RF manipulation were notable in the
multiple passes, multiple treatments, and lower subcutaneous tissue sample. Forty-eight hours
fluence, which is associated with better clinical after treatment, as a result of a healing process,
outcomes and greater patient acceptance [25]. formation of new connective tissue was clearly
Narins et al. reported on rare cases in which visible in the treated sample.
overtreatment of tissue can lead to contour Beyond the benefits of the vacuum
irregularities lasting for more than 6 months. manipulations illustrated above, the in-vivo
While these can be corrected by subcision and experiments showed that the combination
autologous fat transfer, they can be prevented with vacuum technology also has a significant
by eliciting patient feedback. Patient feedback influence on the RF penetration depth. Increasing
regarding heat sensation is a reliable guide to the the intensity level of the vacuum function alone
selection of RF treatment energy settings that contributes to an increased penetration depth.
significantly reduce the risk of overheating tissue For example, using vacuum level 4 in mode I
and subsequent adverse events [26]. (0.8 MHz), increases penetration depth by
The evolution of RF-based devices extends 7.3 mm and 2.7 mm with the B-Contour and
from monopolar systems for skin tightening F-Contour applicators respectively, compared to
to bipolar (and multipolar) devices for many vacuum intensity level 1 (Table 1).
11. Adv Ther (2012) 29(3):249-266. 259
Mode 1 Mode 2 Mode 3
0.8 MHz 1.7 MHz 2.45 MHz
Fig. 2 Thermal images of skin cross-section: the ST applicator set at a RF intensity of 50 J/cm3 and applied with a single
pulse at three RF frequencies: 0.8, 1.7, and 2.45 MHz. The background temperature during the test was 20.0°C, the average
temperature was 29.2°C, and the highest temperature measured was 42°C
Table 1 Heating depths measured with B-Contour and provides a broad range of penetration depths.
F-Contour applicators at the highest and lowest vacuum For instance, with the B-Contour applicator
intensities and RF treatment modes
this range extends from 6.2 mm with the
Vacuum Frequency Depth highest-frequency mode (2.45 MHz – mode
level (MHz) measured III) and lowest vacuum level (level 1) up to
(mm) 18.6 mm with the lowest-frequency mode
B-Contour 4 (highest) 0.8 18.6 A (0.8 MHz – mode I) and the highest vacuum
applicator 4 (highest) 2.45 11.8 B intensity (level 4) (Table 1). This way, the
12.4
1 (lowest) 0.8 11.3 C treatment platform affords practitioners the
1 (lowest) 2.45 6.2 D flexibility to offer a wide range of the industry’s
F-Contour 4 (highest) 0.8 10.7 A most desired treatments.
applicator 4 (highest) 2.45 6.4 B
6.5
1 (lowest) 0.8 8 C
1 (lowest) 2.45 4.2 D
Untreated
The clinical experience gathered using CORE
technology enables precise adapting of tissue
48 hours post RF
heating effects for different applications and
patients. For example, thickness of the dermal
layer in patients may vary from less than 2 mm
to almost 5 mm at different anatomical sites
and skin properties, while some conditions,
like cellulite, require deeper heating of the Fig. 3 Histological assessment of blood vessels in the
subcutaneous layers and others conditions, like adipose tissue of domestic pigs: sectioned with Paraffin-
embedded tissue blot method (30 µm) and stained with
rhytids, require shallower heating of the dermis.
hematoxylin and eosin, 48 hours after RF treatment.
The combination of the three RF frequencies Red and blue arrows indicate red blood cells and plasma,
together with four different vacuum levels respectively
12. 260 Adv Ther (2012) 29(3):249-266.
Cellulite and Body Shaping Treatments show that 91.6% (22/24) of the participants
demonstrated a cellulite grade of 1–2 and only
An overall average improvement of 55% 8.4% (2/24) a cellulite grade of 2–2.33. The mean
in the appearance of cellulite was recorded circumference taken at baseline compared to the
for all participants. In 79% (19/24) of the mean circumference taken at the first (1-month)
participants, the cellulite improvement scores follow-up visit showed an average reduction of
ranged from moderate improvement to 3.31 cm in the buttocks, 2.94 cm in thighs, and
significant improvement. The most significant 2.14 cm in the abdomen. Only at the 6-month
improvement (> 75%) was recorded in subjects follow-up visit was a slight withdrawal observed,
who initially demonstrated a cellulite grade which suggests that maintenance treatment
of 2–3 (see example in Fig. 4). According should be carried out every 3–4 months.
to participants’ assessment of results, all
participants indicated satisfactory results from Skin Tightening Treatments
the treatment course. There was no record of
any dissatisfaction by any of the participants. It In total, 50% of the patients demonstrated
is noteworthy to mention that no withdrawals moderate improvement and 31% of the
were seen either during the study period or at patients significant improvement. A moderate
the 3 follow-up visits (after 1, 2, and 3 months), improvement (51–75%) was recorded in three
indicating consistency of CORE clinical results. of the patients and a significant improvement
In addition, both investigators and participants (> 75%) in two patients who underwent
reported visible and significant improvement in treatments for skin laxity in the abdomen
skin laxity and texture in the treatment area. (see example in Fig. 5). In treatment of the
Evaluations performed at the first follow-up jowls, a moderate improvement (51–75%)
visit clearly show an overall reduction in was recorded in two of the patients and a
cellulite appearance, with a mean cellulite grade significant improvement (> 75%) in one
of 1.38. Final results at the end of the study patient. In treatment of the cheeks, a moderate
Before After
Fig. 4 A 49-year-old woman with grade 2 cellulite and dimpled skin on thighs before (left) and after eight treatment sessions
(right). Results showed a reduction in cellulite volume
13. Adv Ther (2012) 29(3):249-266. 261
improvement (51–75%) was recorded in three levels. This combination provides the operator
of the patients and a significant improvement accurate control when performing the full range
(> 75%) in two (see example in Fig. 6). When of available RF esthetic applications on different
evaluations were taken at the 1- and 3-month body and facial areas. This combination also
follow-up visits and compared to the baseline, plays an important role for patients’ various
the results were sustained and no significant sensitivities and symptoms.
withdrawal was recorded. Moreover, evaluations Since tissue conductivity correlates
indicate that results were sustained over the significantly with tissue temperature [27], the
follow-up duration time and no significant distribution of electrical current can be controlled
withdrawal was recorded in any of the patients. by preheating of the target tissue. Thus, if the
These evaluations indicate that results were temperature of the target tissue is higher than
persistent over the duration of the treatment that of the surrounding tissue, the RF current
course, and no significant withdrawal was will selectively focus in the target tissue [1]. The
recorded in any of the patients. Furthermore, advantage of combining all three RF frequencies
patients’ satisfaction scores were consistent with in CORE technology enables the operator to heat
these results, with 82% of the patients scoring all the skin layers simultaneously. Preheating of
“satisfied” or higher. the skin allows the target tissue temperature to
be attained quickly, significantly decreasing the
DISCUSSION duration of treatment. Once all layers of the skin
reach the temperature of clinical efficacy (in the
The in-vivo experiments indicated that the range of 39–42°C), the operator can easily focus
heating depth achieved using the different on the target tissue. For example, by changing
RF frequencies confirms the theory that RF the operational mode to a low RF frequency
penetration depth in tissue is an inverse function (0.8 MHz), the operator can specifically focus the
of frequency. These experiments showed that treatment on adipose tissue, without any loss
the unique variable frequency capability in of energy and treatment time. In addition, the
CORE technology affects different tissue depths ability to use a different frequency in cellulite
at different RF modes and vacuum intensity treatment can provide not only reduction of
Treated side Treated side
Before After
Fig. 5 A 40-year-old woman with lax, sagging skin on the tummy before (left) and after three treatment sessions (right).
Results showed a noticeable improvement in lax, sagging skin on the tummy
14. 262 Adv Ther (2012) 29(3):249-266.
volumetric treatments. Given the fact that most
patients who have lost weight also have stretch
marks, Viora developed a special combination
protocol with the ST applicator in order to
achieve focused heating over the individual stria
(Fig. 9).
The improvement in elasticity of connective
tissue was examined in vivo by the stress–
relaxation mechanism of fibroblasts which
Before After induces an ectocytotic process that plays a
crucial role in extracellular matrix remodeling
Fig. 6 A 60-year-old woman with lax, sagging skin around
that begins after the contraction phase of
the cheeks before (left) and after six treatment sessions
(right). Results showed a dramatic reduction in the wound repair [28]. The increase in expression
appearance of wrinkles around the cheek of collagen types I and III due to mechanical
stretch was also shown by Kim et al. [29]. Their
research showed that the mechanical stress
this condition but also improvement in skin affects the healing and remodeling process by
laxity and texture in the treated area, as was direct influence on gene expression of collagen
noted by investigators and participants in the types I and III and transforming growth factor
reported case study. The investigators postulated (TGF)-β1, which play a role in the regulation of
this desired effect to be related to the different mechanical strain-induced gene expression.
frequencies, specifically to modes II and III Therefore, in contrast to other systems in
(1.7 and 2.45 MHz, respectively, which target which skin tightening procedures are conducted
the dermal layer). by heat delivery to the dermal layer, the addition
Due to the versatility of the CORE technology of vacuum suction affords added value to the
(ability to change RF energy intensity, vacuum clinical outcomes.
intensity, and, most importantly, RF frequency) Since liposuction and laser-lipolysis
it was possible to not only adjust treatment procedures cannot treat cellulite and sagging
parameters to specific patients’ needs, but also
to develop specific protocols, such as a treatment
protocol for the neck and jowl line. This protocol
is specific for patients both exhibiting local fat
and in need of skin tightening, which combines
the use of the F-Contour and ST applicators
(Fig. 7).
Another special protocol (ReFit protocol)
was developed for patients with sagging loose
Before After
skin after rapid weight loss due to dieting,
exercise, or childbirth (Fig. 8). This protocol is
Fig. 7 A 34-year-old woman with lax skin and local fat in
a skin tightening application using the BC or
the jowl area treated by a combination protocol with FC
FC applicator (not the ST applicator), which and ST applicators: before (left) and after three treatments
is typically used for cellulite reduction and (right)
15. Adv Ther (2012) 29(3):249-266. 263
Before After
Fig. 8 A 27-year-old man with lax, loose skin treated by ReFit protocol, before (left) and after eight treatments (right)
skin, other technologies such as endermologie, therapy requires a more significant investment
u l t r a s o u n d , l a s e r, a n d R F e n e r g y a r e in products or equipment, which is typically
increasingly being used after liposuction and only made by practices specializing in cellulite
laser-lipolysis treatments to smooth and firm treatment. Because for most practitioners
the skin, and remove any residual “lumpiness” cellulite reduction is only one of a large
or swelling. The “firming” procedure may be number of esthetic procedures they offer, the
started 2 weeks after surgery and generally use of combination therapy tends to be limited.
involves a series of 8–12 treatments, depending The exception is combination therapies
on the technology used. Some practitioners involving liposuction, which is often
also use endermologie prior to liposuction, to performed by highly skilled surgeons along
enhance blood circulation and provide a more with a variety of other complex surgical
efficacious result. However, such combination procedures. These physicians often do not
Before After
Fig. 9 A 27-year-old man with stretch marks, before (left) and after eight treatments (right)
16. 264 Adv Ther (2012) 29(3):249-266.
offer noninvasive procedures, and therefore Similar to skin rejuvenation technologies,
may refer liposuction patients to estheticians many physicians use complex body shaping
or others who can provide the finishing skin technologies in order to achieve more rapid
smoothing treatments. and effective clinical results, especially for
The ReFit protocol is very useful for patients with more severe cellulite. For example,
combination with liposuction, laser mesotherapy may also be used in combination
lipolysis (Fig. 10), cavitation ultrasound with other technologies such as RF, ultrasound,
(Fig. 11), etc. and endermologie.
Before After
Fig. 10 A 30-year-old woman before (left) and after two treatments (right) of combined laser lipolysis and ReFit protocol
Before After
Fig. 11 A 45-year-old woman, before and 28 days after treatment of combined cavitation ultrasound and ReFit protocol.
Circumference reduction of 6.8 cm and weight change of 0.2 kg
17. Adv Ther (2012) 29(3):249-266. 265
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ACKNOWLEDGMENTS Arthroscopy. 1998;14:495–501.
9. U.S. Food and Drug Administration. Access data.
Dr. Belenky is the guarantor for this article, Available at: http://www.accessdata.fda.gov/cdrh_
and takes responsibility for the integrity of the docs/pdf2/K021402.pdf Last accessed: January 27,
2012.
work as a whole. Dr. Belenky and Dr. Margulis
are respectively manager and director of Viora’s 10. U.S. Food and Drug Administration. Access data.
Available at: http://www.accessdata.fda.gov/cdrh_
clinical department. Dr. Elman, Dr. Bar-Yosef, docs/pdf9/K090221.pdf. Last accessed: January 27,
and Dr. Paundo do not have any financial 2012.
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