Monopolar Radiofrequency for Skin Tightening: Our Experience and a Review of the Literature Jean Carruthers, MD, FRCSC,* Sabrina Fabi, MD, FAAD,† and Robert Weiss, MD, FAAD‡

BACKGROUND now available.

Effective nonablative skin tightening has become a reality. There are many devices that are

OBJECTIVE To create a concise reference material for existing and new practitioners who wish to be updated about the available technologies. MATERIALS AND METHODS safety and availability.

The authors reviewed the literature from the points of view of efficacy and

RESULTS The increasing number of nonablative systems all seem to be effective and safe when used in the recommended manner. CONCLUSION Radiofrequency energy can be applied to human facial, neck, and body skin to create tightening without surgical incisions and recovery time. The authors have indicated no significant interest with commercial supporters.

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kin tightening using ablative laser systems and chemical peels were important technological strides for patients who wished to rejuvenate and lift their aging skin without surgical skin removal. Subsequent development of minimally invasive procedures, such as nonablative fractional laser, radiofrequency (RF), and microfocused ultrasound treatments, has steadily increased, as patients have opted for less dramatic and more natural results accompanied by desire to minimize risk and recovery time. The novel use, over a decade ago, of RF as an energy source combined with a cooling system to protect the epidermis was a remarkable advancement in the field of skin tightening without epidermal ablation and risk for overcorrection or downtime.1 The first monopolar RF (MRF) device was approved by the Food and Drug Administration for the improvement of periorbital rhytides in November

2002, followed by full face wrinkles in 2004, as well as the temporary improvement in the appearance of cellulite when vibration was added to the delivery system. Since then, several RF current systems have entered the marketplace with similar indications, using different size handpieces to allow for different treatment depths and cooling systems for greater epidermal protection. Different devices use different delivery mechanisms, either continuous motion technique versus a stamp technique, which allow for greater pain relief during treatment, and now, tissue temperature can more precisely be regulated through subcutaneous RF fiber placement.

Mechanism of Action Monopolar RF devices produce heat through a highfrequency electric current (volumetric heating), which flows through the transducer and back to a grounding pad on the subject’s body (Figure 1). The thermal effect achieved in the dermis by the electrically

*Department of Ophthalmology, University of British Columbia, Vancouver, Canada; †Department of Dermatology, University of California, San Diego, California; ‡Maryland Skin Laser and Vein Institute, Cockeysville, Maryland

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© 2014 by the American Society for Dermatologic Surgery, Inc. Published by Lippincott Williams & Wilkins ISSN: 1076-0512 Dermatol Surg 2014;40:S168–S173 DOI: 10.1097/DSS.0000000000000232

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investigation demonstrated that the collagen fibril changes were most prominent at a depth of 3 to 4 mm and most obvious 8 weeks after MRF treatment. This may be a result of the natural healing process.3 Treated skin demonstrated an elevation of collagen messenger RNA (mRNA) expression by Northern blot analysis compared with untreated skin. In this study, collagen Type I mRNA steady-state expression measured 2.4-fold higher than that of the untreated control on Day 2 and 1.7-fold that of the control 1 week after treatment. However, after 3 and 8 weeks after treatment, mRNA levels decreased slightly below control levels.3

Treatment Administration Figure 1. Radiofrequency technology design in a monopolar (unipolar) configuration: energy is dispersed through the skin to the whole body, which necessitates an intensive contact cooling to prevent epidermal damage (blue electrode).

generated radiowaves can be calculated using the formula: Energy (in joules) = I2 · R · T (where, I = current, R = impedance of the tissue, and T = time of application). The authors believe that this equation is derived from Ohm’s law, which is: V ðvoltageÞ 5 I ðcurrentÞ · R ðresistenceÞ: The electrical current heats the deep dermis, fat, fibrous septae, and with some new delivery systems placed below the skin, fascia as well. Monopolar RF energy is not reflected or absorbed by epidermal melanin or vasculature, as it passes through the skin, making it safer to use in all skin types.2 This heating of the dermis and subcutaneous fibrous septae is associated with collagen denaturation and subsequent thickening and shorting of the collagen fibers, leading to increased fibroblast activity and new collagen formation, resulting in skin tightening over 4 to 6 months.1–3 The amount of newly produced collagen seems to be dependent on the intensity of heating of connective tissue and time that the tissue is heated. A dose–response

Depending on the MRF system used, energy can be delivered in a “stamped” mode, a continuously gliding movement, or internally along the dermal– hypodermal interface through a fiber or electrode. With the MRF device that uses a stamping method (Thermage [Comfort Pulsed Technology {CPT}] system; Solta Medical, Hayward, CA), a short 4-second pulse incorporates cryogen cooling bursts throughout the pulsed RF delivery while the treatment handpiece is held in place, and skin temperature is simultaneously measured with each pulse so that the epidermal temperature does not exceed 45C, but the heat delivered to the dermis is about 45C. Conversely, a continuous motion technique is used to deliver RF energy by other MRF devices (Exilis system; BTL Aesthetics, Prague, Czech Republic) and Pelleve (Ellman International, Inc., Oceanside, NY). One system (Exilis system; BTL Aesthetics) uses a cooled gliding electrode ball tip and has an integrated “energy flow control system” eliminating peaks of RF energy, as well as a sensor monitor to alert the user if cutaneous contact has been lost. Both the body handpiece and the facial applicator handpiece incorporate a bipolar grounding pad, which allows real-time monitoring of impedance, so that spikes in RF delivery are eliminated, increasing patient safety and comfort. Whereas the other system (Pelleve; Ellman International, Inc.) emits RF energy in the form of electromagnetic waves, cooling the epidermis in part with gel and in part by convection to the surrounding air, which occurs because of the

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MONOPOLAR RADIOFREQUENCY FOR SKIN TIGHTENING

mobile technique used by this device. An infrared laser thermometer (ILT) is used to ensure that epidermal temperatures are maintained between 41C and 43C. More recently and minimally invasive device (ThermiTight; ThermiAesthetics, Southlake, TX) has been introduced into the market that uses temperaturecontrolled RF through a fiber that is inserted subcutaneously to heat the dermal–hypodermal interface, bypassing the epidermis altogether. The system delivers MRF energy directly into the subdermal tissue through a 600-mm electrode enclosed in a 1-mm cannula and extending 1 to 2 mm beyond the distal end of the cannula. The internal temperature can be set to 60C to 70C (optimal temperature to achieve collagen denaturation), and an internal temperature monitor automatically turns off the system if the internal temperature exceeds the set temperature by 7C. Simultaneously, a forward looking infrared camera (FLIR) (FLIR E40; FLIR Systems, Inc., Wilsonville, OR) allows for radiometric infrared video streaming with thermal monitoring of the entire epidermis in the treatment field rather than a single spot. Some patients receive an anxiolytic medication before MRF treatment. Strong systemic analgesics and/or local anesthetic infiltration are not advisable, as patient feedback is relied on to avoid epidermal burns when delivering MRF energy externally. An external vibration device can be used during treatment to mitigate discomfort through the gate theory of nerve conduction. Otherwise, some devices have a vibration setting incorporated in the handpiece (Thermage CPT system; Solta Medical, Hayward, CA) that allows vibratory stimulus to be delivered throughout the MRF pulse.4 Topical anesthetics may also alleviate some initial discomfort, but in general, are ineffective in mitigating pain from deep dermal heating. Complete removal of topical anesthetics and any surface residue is recommended to prevent epidermal burns. Coupling fluid or gel needs to be applied in between the externally applied MRF transducer and the receiving skin. If grid markings are used to guide RF treatment, they need to not contain metal because of the risk of overheating the

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metal particles. When using an internal RF probe, the area to be treated is lightly infiltrated with a tumescent lidocaine solution, avoiding excessive infiltration not to decrease the impedance of the subdermal tissue to be treated. Energy and number of passes are device dependent and also vary depending on the body surface area where the treatment is being applied. In a study comparing the responses of 5,700 treated patients with the original RF monopolar algorithm of high-energy single-pass treatment with a multi-pass algorithm of lower energy and multiple passes, better results and increased comfort were seen with the low-energy multiple-pass algorithm.5 Main contraindications for MRF therapy are having a pacemaker or metal implant near the treatment area.

Clinical Studies Fitzpatrick and colleagues6 performed a multicenter blinded clinical trial in 86 patients who were treated with high-fluence MRF energy (Thermage; Solta Medical). Independent scoring of blinded photographs demonstrated Fitzpatrick wrinkle score improvements of at least 1 point in 83.2% (99/119) of treated periorbital areas. Fifty percent (41/82) of subjects were either satisfied or very satisfied regarding the degree of reduction in periorbital wrinkles. Photographic measurement demonstrated that 61.5% (40/65) of eyebrows were lifted by at least 0.5 mm. This resulted in FDA clearance for this device for periorbital wrinkles and rhytides. Unfortunately, this initial high-fluence treatment protocol was later associated with significant side effects, such as scars and surface irregularities, as frequently treatments had been performed under regional blocks or general anesthesia and subjects could not provide sensory feedback of heat or pain sensation. A revised protocol of multiple passes with lower fluences resulted in significantly higher collagen deposition at deeper levels. This study demonstrated the ability to provide consistent results in the setting of higher patient safety and comfort during administration of the treatment.7

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Cheek, submental, and neck laxity were treated with MRF by Alster and Tanzi.8 Fifty patients (skin phototypes I–IV) with mild-to-moderate cheek laxity (n = 30) or neck laxity (n = 20) received 1 treatment with an MRF device (ThermaCool; Thermage Corp., Hayward, CA). Fluences ranging from 97 to 144 J/cm2 (level of 13.5–16; average of 130 J/cm2) on the cheeks and 74 to 134 J/cm2 (level of 12–15.5; average of 110 J/cm2) on the neck were used. Standardized photographs were evaluated using a quartile grading scale by independent evaluators at 1 week and at 1, 3, and 6 months after treatment. Patient-reported outcome surveys were completed during each follow-up visit. Significant improvement in cheek and neck skin laxity was observed in the majority of patients, and patient satisfaction scores were consistent with the clinical improvement seen. A retrospective study was conducted to evaluate the efficacy and safety of the newer generation MRF device with a vibrating tip (Thermage CPT System; Solta Medical) for facial skin tightening. Sixty-four patients with mild-to-moderate facial skin laxity were treated to the forehead, cheek, jawline, and upper neck, with 2 consecutive passes to the full treatment area and vectors at the providers’ discretion on areas needing greater skin tightening. Energy levels ranged between 14 and 24 J/cm2, with an average of 900 pulses delivered. On average, a Level 2 vibration was used on patients who could tolerate the vibration. Paying patients were surveyed between 1 and 10 months after treatment to determine the degree of improvement, satisfaction, and presence of side effects. With the new system, 80% (n = 51) reported at least mild correction of skin laxity and 55% (n = 35) noticed skin texture improvement. The patients who were 4 to 6 months out from their procedure had significantly better correction in skin laxity than those 1 to 3 months out. Improvement in skin laxity correction was also significantly improved (although less so) 7 to 10 months out compared with those 1 to 3 months out. On average, pain level was 6.21 (0–10 scale), 9% (n = 6) found the procedure too painful, whereas only 43.8% (n = 28) would have the procedure again. One patient reported blistering after her treatment, and after investigation, the tip was deemed faulty. No scarring or prolonged pain or fat atrophy was reported in any patients treated.9

The novelty of combining continuous RF wavelength delivery with Peltier cooling (BTL Industries, Inc., Prague, Czech Republic) has found wide acceptance. There are 2 different hand applicators, 1 for face and the other for body. The goal of treatment is to deliver enough RF energy that the treated skin warms to 40C to 43C for 10 to 15 minutes for each region treated. The device is flexible in that if one wishes to target skin laxity, the cooling can be turned off, but should one wish to target subcutaneous fat, the cooling can be turned on to drive the RF energy into the fatty layer. The infrared sensor in the body tip continuously monitors skin temperature, and the impedance measured by the tip confirms proper tip contact with the skin. This is possible with the use of a proprietary bipolar grounding pad that is used to detect impedance of RF delivered to the grounding pad. If tip contact or energy flow is interrupted, the computerized circuitry automatically shuts off the system, which virtually eliminates the risk for arcing and skin burns. Standard treatment protocols are for treatments of 10 minutes for a 20 · 25 cm area, keeping surface temperature at 40C to 43C, repeated 4 times spaced 7 to 10 days apart (Figure 2).2 When 49 subjects received a total of 2 continuous rolling MRF treatments (Pelleve; Ellman International Inc.) with epidermal temperatures measured at 41C to 43C for 5 heat cycles to the face and neck 1-month apart, 3-dimensional photographs revealed an overall improvement in 74% (by Patient Global Aesthetic Improvement Score) of study subjects.10 Eighty-five percent of patients noted an overall improvement in the appearance of their skin. Eighty-one percent of patients rated their post-treatment skin laxity as improved, 85% rated their skin smoothness as improved, and 62% rated their skin brightness as improved. When a multicenter study was undertaken to determine the efficacy of the MRF system (Pellevé S5 Wrinkle Treatment Generator; Ellman International Inc) in tightening the skin of the hands, a total of 31 female patients with a median age of 56 years were enrolled in 2 centers.11 Each had a single hand treated, with randomization of the hand to be treated. A total of 3 treatments were performed at 2-week intervals. Follow-up photographs were taken at 45

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using subsurface temperatures of 50C to 60C. Seventy percent of patients demonstrated an improvement on a 4-point skin laxity score.12 One patient experienced a localized vesicle, which resolved without intervention; otherwise, no adverse events were noted. The Trusculpt by Cutera is an MRF technology that while used to treat small areas of excess fat may in vitro confer a skin-tightening effect. This novel MRF technology when tested (in vitro) demonstrated that temperatures of 45C sustained in adipose tissue for 3 minutes resulted in 60% loss of cell viability because13,14 deep heating of the subcutaneous adipose tissue triggers cell apoptosis. The device’s large electrode enables high current densities to depths of 7 to 15 mm to target subcutaneous fat. Such a device when used in humans may allow for differential delivery of heat to varying fat thicknesses and anatomic areas. The authors await with great interest in this new device the human in vivo studies that will also evaluate skin tightening.

Adverse Events

Figure 2. (A) Lower facial contours before Exilis RF treatment. (B) Improved lower facial contours after Exilis treatment.

and 90 days after the final treatment. At 90 days, 89% of patients had visible improvement of the appearance of the treated hand based on the visual Global Aesthetic Improvement Scale. Of these, 50% had visible improvement from baseline, and 39% had marked improvement from baseline. Patients reported only mild-to-moderate discomfort during the treatment. No adverse events or side effects were reported. An internal RF treatment that provides novel real-time subdermal and epidermal temperature monitoring has surfaced (ThermiTight; ThermiAesthetics), which allows greater subdermal temperatures and may possibly translate to superior results. Seventy patients underwent submental and/or jowl treatment, with (32) or without (38) lipoaspiration,

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Complication rates from MRF have been confined to the company-provided data and have been extremely low, especially with the newer generation technologies. Transient edema and erythema usually fade in a day or so. Numbness of skin, often in the distribution of the greater auricular nerve, can occur but resolves with time, as there is no anatomic disruption of the nerve. Sensory feedback mechanisms built into the tips have meant that small superficial skin burns are rare. Tissue irregularities related to tissue overheating, with an estimated rate of 0.08% in more than 161,000 uses, have been reported by the manufacturer. The complication rate reported by the manufacturer is 0.03%,1,15 but the thermal burn rates reported by Alster and Tanzi and Fitzpatrick and colleagues6,8 are informative, and the subsequent protocol modifications are the likely reason for the decrease in burn rates. With newer subsurface RF treatments, transient marginal mandibular palsies have been reported after jowl treatment. A greater degree of swelling has been noted anecdotally compared with externally applied RF treatment, and some bruising may also be seen

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primarily because local anesthetic infiltration is performed before treatment. As the FLIR camera system has been found to be more accurate than ILT, the risk for epidermal burns may be expected to be less.16

References 1. Dierickx C. Clinical insight the role of deep heating for noninvasive skin rejuvenation. Lasers Surg Med 2006;38:799–807. 2. Beasley K, Weiss R. Radiofrequency in cosmetic dermatology. Dermatol Clin 2014;32:79–90. 3. Zelickson BD, Kist D, Bernstein E, Brown D, et al. Histological and ultrastructural evaluation of the effects of a radiofrequency based nonablative dermal remodeling device: a pilot study. Arch Dermatol 2004;140:204–9. 4. Greene RM, Green JB. Skin tightening technologies. Facial Plast Surg 2014;30:62–7. 5. Dover JS, Zelickson B; 14-Physician Multispecialty Consensus Panel. Results of a survey of 5,700 patient monopolar radiofrequency facial skin tightening treatments: assessment of a low-energy multiple-pass technique leading to a clinical end point algorithm. Dermatol Surg 2007; 33:900–7. 6. Fitzpatrick R, Geronemus R, Goldberg D, Kaminer M, et al. Multicenter study of noninvasive radiofrequency for periorbital tissue tightening. Lasers Surg Med 2003;33:232–42. 7. Narins R, Tope W, Pope K, Ross EV. Overtreatment effects associated with a radiofrequency tissue tightening device: rare, preventable, and correctable with subcision and autologous fat transfer. Derm Surg 2006; 32:115–24. 8. Alster TS, Tanzi E. Improvement of neck and cheek laxity with nonablative radiofrequency device: a lifting experience. Dermatol Surg 2004;30(4 Pt 1):503–7.

9. Edwards AF, Massaki A, Fabi SG, Goldman MP. Clinical efficacy and safety evaluation of a new monopolar radiofrequency (mRF) device with comfort pulsed technology for the treatment of facial skin laxity: 10 month experience with 64 patients. Dermatol Surg 2013;39(1 Pt 1): 104–10. 10. Chipps L, Bentow J, Prather HB, So JJ, et al. Novel nonablative radiofrequency rejuvenation device applied to the neck and jowls: clinical evaluation and 3-dimensional image analysis. J Drugs Dermatol 2013; 12:1215–8. 11. Vega JM, Bucay VW, Mayoral FA. Prospective multicenter study for safety & efficacy unique RF device for hand wrinkles. J Drugs Dermatol 2013;12:24–6. 12. Key D. Going deeper, a new approach to skin tightening: integrating the use of skin thermal imaging with subsurface RF probe feedback loop heating. Presented at: American Society for Laser Medicine and Surgery Conference; April 4–6, 2014; Phoenix, AZ. 13. Franco W, Kothare A, Goldberg DJ. Controlled volumetric heating of adipose tissue using a novel radiofrequency technology. Lasers Surg Med 2009;41:745–50. 14. Franco W, Kothare A, Ronan SJ, Grekin RC, et al. Hyperthermic injury to adipocyte cells by selective heating of subcutaneous fat with a novel radiofrequency device: feasibility studies. Lasers Surg Med 2010;42: 361–70. 15. Weiss R, Weiss M, Munavalli G, Beasley K. Monopolar radiofrequency skin tightening. A retrospective analysis of efficacy and safety in over 600 treatments. J Drugs Dermatol 2006;5:707–12. 16. Key D. Comprehensive thermoregulation for the purpose of skin tightening using a novel radiofrequency treatment device: a preliminary report. J Drugs Dermatol 2014;13:185–9.

Address correspondence and reprint requests to: Jean Carruthers, MD, FRCSC, University of British Columbia, Vancouver, BC, Canada, or e-mail: [email protected]

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Monopolar radiofrequency for skin tightening: our experience and a review of the literature.

Effective nonablative skin tightening has become a reality. There are many devices that are now available...
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