The first RF device developed was the monopolar RF device ThermaCool (Thermage, Inc., Hayward, CA, USA; now Solta Medical, Inc.), which demonstrated improvement of skin laxity on the face and neck. The concept is that the device delivers a uniform, volumetric heating effect into the reticular dermis, generated by the tissue’s resistance to the current flow13. Cooling occurs through a digitally pulsed cryogen spray in the treatment tip, which helps prevent damage to the epidermis56.
The original Thermage systems used a high-energy output, which resulted in patients experiencing significant discomfort. Only approximately 70% of patients believed the treatment met their expectations. Since its development in 2002, there have been advances in tip geometry and energy delivered, which has resulted in more efficacious treatment in less time, as well as increased patient satisfaction. In one particular study, 94% of patients stated the treatment met their expectations57, 58. Furthermore, a 2006 study demonstrated that there was twice the amount of collagen denaturation after three passes were performed on lower energy settings, rather than one pass at a higher energy setting59, 60.
The major advantages of RF treatments for photorejuvenation are the minimal side-effects and downtime. The most common side-effects are mild erythema and oedema lasting less than 24 hours61. There are, however, some contraindications for the use of RF therapy in patients with pacemakers, defibrillators, implantable cardioverter–defibrillators, and other implantable electronic devices62. This is an especially important consideration in the ageing population. Relative contraindications also include any conditions that would predispose a patient to poor wound healing, including smoking, autoimmune conditions and prior radiation therapy62.
Combination device therapies
The combination of electrical and optical energy has been implemented to enhance the non-ablative effects of either device alone, as well as allow for lower levels of each energy type, thereby potentially reducing the risk of associated side-effects63. Combination treatments typically do not require systemic analgesia and are well-tolerated with topical anaesthetic creams64. Therapy using simultaneous infrared laser at 900 nm with bipolar RF, as well as IPL at lower fluences with bipolar RF, has been evaluated for the systematic reduction of photodamage and rhytides. The combinations demonstrated tissue contraction as well as effects on laxity, rhytides and photodamage in general65–68. The IPL combined with RF into a single pulse has been termed an electro-optical synergy system (ELOS, or elōs; Syneron Medical, Inc., Yokneam, Israel). Using this system on 108 patients, Sadick et al demonstrated improvement in wrinkle reduction, erythema, telangiectasias, and hyperpigmentation, as well as a patient satisfaction rating of 92%65.
In addition to heat exposure, mechanical stress from the application of a vacuum has been reported to stimulate fibroblasts, which leads to collagenesis. This combination increases blood perfusion to the treatment area, supporting fibroblast activity and the rejuvenation process as a whole69. The Isōlaz system (Solta Medical, Inc., Hayward, CA, USA) allows for manipulation of the optical characteristics of the skin by incorporating a vacuum to pull the dermis closer to the surface of the skin then exposing it to light, which improves the efficiency of energy transmission70–72. This allows the physician to treat the target area with lower wavelength light and lower fluences, increasing efficacy and decreasing patient discomfort73.
The Polaris WRA™ (Syneron Medical Inc.) device uses both bipolar RF energy and diode laser at 900 nm to simultaneously treat rhytides and skin laxity. The RF energy penetrates the skin, heating deeper tissues and inducing neocollagenesis, while the diode laser targets pigmentation and vascular issues that are more superficial74. Yu et al compared the Polaris device to ReFirme ST™ (Syneron Medical, Inc.), which uses bipolar RF energy to supplement infrared laser at 700–2000 nm and induce non-painful skin tightening by remodelling dermal tissue without damaging the epidermis75, 76. Although there were no statistically significant differences between the two devices for general skin improvements, histopathological changes showed a higher collagen fibre density after treatment with the Polaris WRA. Furthermore, there were statistically significant improvements
in the cheek, jowl and nasolabial folds with Polaris WRA and in the nasolabial folds treated with ReFirme ST75.
Conclusions
The face and hands receive the most exposure to sunlight throughout a person’s lifetime, and therefore show the most photodamage in the form of dyspigmentation, texture changes, wrinkles and loss of volume. Although the majority of aesthetic dermatologic treatments target the face, rejuvenation of the hands to treat photoageing is also an important consideration. Technology has evolved from painful procedures that required significant downtime to non-painful, non-invasive procedures with no downtime and effective results. Specifically, light and RF-based technologies continue to be implemented and improved on to achieve the optimum degree of photorejuvenation for the aesthetic patient. These procedure can be combined with volume replacement using fillers or fat to yield optimal hand rejuvenation outcomes.
