Hybrid and Combination RF Technologies
Hybrid RF systems use monopolar and bipolar mechanisms (Accent RF; Alma Lasers, Ltd., Caesarea, Israel). The monopolar handpiece achieves deep volumetric heating of the skin through alternating current of the electromagnetic field. The bipolar handpiece is used for more superficial localized (nonvolumetric) heating based on tissue impedance.[40,41] Studies evaluating the use of hybrid monopolar/bipolar RF for the treatment of facial rhytids and skin laxity found that 56% of participants had improvement. When stratified by age, the young patients had higher satisfaction scores when compared with the older patients. This may be explained by inherent changes of collagen cross-linking leading to irreducible multivalent cross-links as tissues age. A split face study by Alexiades-Armenakas et al compared the combined monopolar/bipolar RF for the treatment of facial rhytids and laxity. Although there was a slightly greater degree of improvement with the bipolar handpiece, this difference did not reach statistical significance.
A number of combination technologies have been developed to change tissue impedance and improve safety and efficacy of heat generation. One of the most widely studied bipolar RF devices uses electro-optical synergy (ELOS) with broadband light (Syneron Aurora) or with a diode laser (Syneron Polaris) (Syneron Medical Ltd., Yokneam Elite, Israel). This technology is termed ELOS.[4,15] Most commonly, the ELOS systems include intense pulsed light (IPL), diode laser, or infrared light. The concept is that combination optical and bipolar RFs allow for lower energy delivery to achieve target heating, thus minimizing discomfort and complications.[15,21,43] Photothermolysis is used to preheat the target tissues, which in turn changes tissue impedance and susceptibility to RF. The RF also allows for deeper penetration into the dermis than nonablative lasers, which tend to disperse in the soft tissue.[1,4] Early systems such as Aurora SR and Polaris WR (Syneron Medical Ltd.) used the bipolar configuration with an IPL and a 900-nm diode laser, respectively. The Aurora SR system was studied by El-Domyati et al to evaluate histologic and clinical changes in periorbital region of 6 subjects over 6 treatments. At 3 months, improvements in skin tightening, texture, wrinkles, and overall satisfaction were 75%–80%,70%–75%,95%–100%, and 95%–100%, respectively. Histologic analysis confirmed these findings with increased epidermal thickening, a 53% reduction in elastin content, and a 28% increase in newly synthesized collagen fibers. Sadick et al conducted a clinical study using Aurora SR, which reported similar findings on 108 patients. Overall skin improvement was 75.3%, which included wrinkle improvement, pore size, and pigmentation, among other factors, and skin laxity improved 62.9%. Patient satisfaction was 92% at 15 weeks posttreatment. The Polaris WR system was also studied for facial rhytids and skin laxity. The combination of RF and diode laser energy accomplished improvements in skin laxity and rhytids, most notably in the periorbital region, with continued skin laxity improvement at 6 months posttreatment. Newer ELOS platforms incorporate both the IPL and diode laser with RF.
Another combination technology includes vacuum with bipolar RF, termed functional aspiration controlled electrothermal stimulation (Aluma; Lumenis Inc., Santa Clara, Calif.). The vacuum folds the skin and subcutaneous fat to ensure contact and positioning of the dermis in optimal alignment with the RF energy path. This avoids heating nontargeted structures (ie, muscle). Some theorize that the mechanical stress on fibroblasts from the vacuum may increase collagen formation and clinical efficacy. The vacuum-assisted bipolar RF technology was studied by Gold et al in 46 patients with facial aging. The mean elastosis score (Fitzpatrick-Goldman Classification) decreased from 4.5 (pretreatment) to 2.5 (6 months posttreatment). Despite overall clinical success, the investigators noted that patient satisfaction levels declined during the follow-up period. The authors postulate that this may be a common finding with RF treatments as the effect is incrementally progressive over the number of months required for wound healing and neocollagenesis. Side effects of the vacuum-assisted RF are similarly infrequent to standard RF and include erythema, burns, blistering, edema, and transient hyperpigmentation. Today, newer devices are combining all of these technologies (laser, vacuum, and RF) to achieve higher satisfaction of nonablative facial rejuvenation.
Plast Reconstr Surg Glob Open. 2020;8(8):e2861 © 2020 Lippincott Williams & Wilkins