Microwaving away the skin sag: rejuvenation via radiofrequency

The rejuvenation methods employing radiofrequency are based on radiowaves of certain frequency to penetrate and be absorbed by body tissues. The absorption of radiowaves causes tissue heating as well as some structural molecular changes. (An essentially similar effect is used in microwave ovens where high-frequency radiowaves heat and cook food.)

The radiofrequency treatment is usually delivered by placing an electrode onto the skin and applying alternating current of the required frequency. As a result, the skin is deep-treated with controlled doses of targeted radiowaves. At the same time, the skin surface layer, consisting of the epidermis and upper dermis, may be cooled by a cryogenic spray to prevent open burns (especially when higher levels of energy delivery are employed). The treatment produces localized heat injury of the dermis and subdermal layer as well as the collagen contraction leading to skin tightening. The subsequent healing of the microscopic dermal and subdermal lesions causes further skin tightening and also reduces the depth of wrinkles. Notably, since the skin surface is preserved, the downtime after the procedure is relatively short.

In theory, this approach makes good sense. First, most of the ideas behind it have been in practical use for years. Such well-established rejuvenation methods as laser skin resurfacing, dermabrasion and deep chemical peels, are partially based on skin remodeling following a controlled injury. Second, radiofrequency tissue tightening is being used with reasonable success in other areas of medicine. For instance, endoscopic radiofrequency devices are employed to tighten sphincters in the GI tract.

In practice, the initial results of practical use of radiofrequency in skin care have been mixed. Thermage, the procedure performed with the device ThermaCool, was the original commercial application of radiofrequency in skin rejuvenation. It demonstrated that skin tightening could be achieved but was usually relatively modest (albeit some people experienced dramatic improvements) whereas the incidence of side effects and unsatisfactory results was not insignificant. A particularly vexing problem was excessive loss of subcutaneous fat seen in a relatively small percentage of patients. Such undesirable and potentially permanent side effect could apparently result from overheating of subcutaneous fat. In order to reduce or eliminate the above risks, several new distinct types of radiofrequency treatments as well as new variants of Thermage procedure have been developed. The key features of each are discussed in the following sections.

Monopolar radiofrequency (Thermage/Thermacool)

Monopolar delivery of radiofrequency for cosmetic rejuvenation is based on applying a single electrode to the treated area whereas the opposing electrode is relatively far removed so that the current goes deeply through the body. As a result, the tissue in the treated area is heated rather deeply (usually up to 20 mm) and intensely, which arguably increases both the potential benefits and risks. The more recent versions of monopolar radiofrequency procedures are claimed to have an improved risk/benefit profile. Monopolar radiofrequency is typically used to treat facial sag, skin laxity, and cellulite. The best-known procedure based on monopolar radiofrequency is Thermage, which is performed with the device Thermacool. For more details, see the fact-sheet on monopolar RF.

Bipolar radiofrequency plus laser/light (Refirme, Polaris via ELOS Technology)

Bipolar delivery of radiofrequency for cosmetic rejuvenation is based on applying two closely positioned electrodes to the treated area. The electric current that goes between the electrodes is relatively small and shallow. As a result, the tissue in the treated area is heated less deeply (usually up to 2-4 mm) and less intensely (compared to monopolar RF devices). As a result, bipolar radiofrequency procedures tend to be safer and gentler than the monopolar ones. In particular, since bipolar RF effects are relatively shallow, there is less risk of the overheating and subsequent loss of facial fat, a side-effect sometimes seen after monopolar treatments. Conversely, bipolar radiofrequency is less useful for indications when deep tissue heating may be desirable, such as cellulite treatment and sculpting.

Typically, a single bipolar RF treatment would produce less noticeable results than a monopolar one. Hence bipolar RF procedures are often done in a series of several treatments whose benefits are believed to be cumulative.

In commercial rejuvenation systems, bipolar RF is usually combined with other energy sources, particularly lasers or intense pulsed light, which are believed to act synergistically with RF and help achieve better subsequent dermal remodeling. Hence, in addition to skin tightening, such treatments are also used to improve wrinkles and fine lines. In particular, the so-called ELOS (electro-optical synergy) technology developed by Drs. Shimon Eckhouse and Michael Kreindel at Syneron has been commercialized in Refirme and Polaris systems for skin tightening and wrinkle reduction. For more details, see the fact-sheet on bipolar RF + laser/light.

Fractional bipolar radiofrequency (eMatrix)

Another approach to improving the risk/benefit profile of bipolar radiofrequency is to combine it with the fractional approach that has been used in other directed energy treatments (e.g. lasers) for some years. The idea of the fractional approach to directly energy treatments is to treat many very small discontinuous areas of the skin in a grid-like fashion (as opposed to treating large contiguous areas). Presumably it is easier for the body to repair many small lesions than a single large one. This provides a way to apply greater energy density without necessarily increasing the rate of side effects, or, conversely, to reduce the rate of side effects while applying standard energy density.

Commercial treatment systems that combine bipolar radiofrequency with the fractional approach are available. In particular, eMatrix system by Syneron corporation uses a proprietary variant of fractional bipolar radiofrequency technology trademarked Sublative Rejuvenation®. For more details, see the fact-sheet on fractional bipolar RF.

Monopolar plus bipolar radiofrequency (Tripollar, Accent RF Monopolar/Bipolar)

Since monopolar and bipolar radiofrequency treatments appear somewhat complimentary, some rejuvenation devices combine both. In particular, TriPollar device (by Pollagen) has both monopolar and bipolar electrodes on the same hand-piece. The manufacturer claims that their special algorithms of simultaneous application of monopolar and bipolar RF to the treated area reduce the side effects while maximizing the benefits. The Accent RF device has separate monopolar and bipolar hand-pieces, which the physician can use sequentially in the same treatment session. For more details, see the fact-sheet on monopolar + bipolar RF.

DIY Radiofrequency treatments at home

Radiofrequency treatments seems to be expanding into the realm of home use. In particular, Pollagen has launched two devices for self-administering radiofrequency treatments at home: TriPollar Stop (primarily for wrinkles and skin tightening) and TriPollar Pose (primarily for fat reduction and cellulite). (As of the time of this writing, these devices are available only in Europe but can probably be purchased via the internet and shipped elsewhere.) Apparently, home radiofrequency devices are adapted to use lower energy settings than their professional counterparts in order to reduce potential risks resulting from unskillful or excessive application. It remains unclear whether home radiofrequency devices can deliver benefits comparable to those of the professional ones - or any benefits at all for that matter. In theory, radiofrequency treatment might be beneficial even at relatively low energy settings of home use, especially considering that patients can self-administer the treatment multiple times (within manufacturer's guidelines) at no additional cost. In practice, the benefits of at-home RF remain to be proven. Studies are needed comparing at-home RF treatments to the professional ones as well as to placebo (sham treatment).

Monopolar radiofrequency (Thermage/Thermacool)
Bipolar radiofrequency plus laser/light (Refirme, Polaris via ELOS Technology)
Fractional bipolar radiofrequency (eMatrix)
Monopolar plus bipolar radiofrequency (Tripollar, Accent RF Monopolar/Bipolar)