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RADIOFREQUENCY
RADIOFREQUENCY
RF uses an alternating electrical current to deliver energy to the skin. The purpose of RF devices used for minimally invasive cosmetic treatments of the face and body is to produce selective dermal injury, leading to a responsive wound repair while keeping the overlying epidermis intact.68,69 The electrical current heats the deep dermis, fat, fibrous septae, and (with internally applied monopolar RF devices) fascia. 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. This volumetric heating of the dermis and subcutaneous fibrous septae is associated with collagen denaturation and subsequent thickening and shortening of the collagen fibers leading to increased fibroblast activity and new collagen formation resulting in skin tightening over 4 to 6 months. An advantage this technique employs over fractional lasers is a low risk of postinflammatory hyperpigmentation.70
In a prospective, multicenter study using a monopolar RF device for moderate to severe hand wrinkles, 31 patients receiving 3 RF treatments at 2-week intervals showed a 50% improvement from baseline with no adverse effects reported.71 For the treatment, the RF device (Pelleve S5 Wrinkle Treatment Generator; Ellman International Inc., Oceanside, NY; 4.0 MHz, 120 W) with a 20-mm handpiece (GlideSafe; Ellman International Inc.) was set at a level of energy based on verbal feedback about tip warmth from the patient. The handpiece was moved in continuous overlapping corkscrew patterns to completely cover each of the three gel-coated treatment zones. When the skin surface temperature of the treated areas reached 40ยฐ to 42ยฐC, the
treatment was continued for an additional 3 minutes. This sequence was then repeated for a total of 2 passes in each zone.
Microneedle fractional RF systems generate precise ovoid areas of coagulation in the dermis and subcutaneous tissue, bypassing the epidermis. The location of the thermal injury depends on needle depth and conduction times. The technology has been studied on the face and neck for skin rejuvenation and treatment of acne scars. While no studies have yet evaluate its use on the dorsal hands, keeping the intensity low and the depth of needle penetration shallow is advisable.