**5. Advantages of radiofrequency energy**

Radiofrequency (RF) is a form of electromagnetic energy that can be converted to thermal energy. It does not target a particular chromophore. The early RF devices created bulk heating. When thermal energy emanated from the device tip, adjacent tissue heating occurred, leading to gradual warming and uneven heating, which became problematic and unpredictable in large treatment surface areas. With gradients of heat, areas of fibrosis can result from excessive heat delivery, which introduces further potential issues in regions of pre-existing compromised blood flow, little adiposity, and thin skin. Multiple RF devices, monopolar (Thermi) and bipolar (Invasix, InMode) with internal and external temperature probes and indwelling liposuction aspiration cannulas, were introduced in the past 12 years. With encouraging results, and safety features that monitor treatment depth and skin temperatures to help avoid visible burns, or the safety to offer rapid cooling to avoid burns altogether, the use of RF devices for enhancing body contouring have gained traction [11, 12]. In addition, other aesthetic applications have emerged to shrink lax soft tissue, as for SMAS tightening during rhytidectomy and popcorn capsulorraphy in breast implant repositioning surgery, and ongoing efforts to manage abdominal wall fascial laxity [13]. As described in the next section, a novel RF based device, Renuvion® (Apyx™ Medical), uses an energized stream of helium gas, known as a plasma, for the same purpose of precise soft tissue subdermal coagulation.

Like the lasers, the thermal energy delivered by an RF device can be calculated and provide treatment guidelines. The amount of energy is the product of the square of current multiplied by tissue impedance multiplied by the time of application [5, 14]. As adipose tissue has high tissue resistance or impedance to electromagnetic current, it has proven to be a good target for RF technologies to diminish iatrogenic tissue laxity and enhance liposuction results. Recalling that the total ability to re-drape the skin is related to the contractile nature of the dermis, as reflected by dermal thickness, the amount of FSN and fat to be aspirated, the delivery of RF energy to multiple tissue planes has proven advantageous. Treating the immediate subdermal layer leads to neo-collagenesis and subdermal remodeling, while treating above and below Scarpa's fascia maximally augments fat liquification, coagulates blood vessels, and creates an active fibroblastic reaction that replaces liquified fat [15, 16], neo-angiogenesis, and a compact, reorganized layer of collagen and elastin over 4–6 months [17]. The delivery of immediate heating between 60 and 80°C

*Contractile Effects of Radiofrequency Energized Helium Plasma on the Fibrous Septal Network DOI: http://dx.doi.org/10.5772/intechopen.97849*

causes collagen fibrils to contract to one third their length and alters the microenvironment of the extracellular matrix toward favorable remodeling and healing. This begs the question as to whether repeated thermal effects on dermal ground substance can occur, and if there is a role for retreatment in secondary surgery to gain additional contraction. Notwithstanding, significant longevity of skin contraction has been demonstrated in clinical bipolar RF assisted liposuction studies that have shown 25% soft tissue area contraction at 6 months and 35–40% at one year [18]. As radiofrequency offers immediate and long- lasting thermal contraction of the FSN and inflammatory dermal heating, it has come to the forefront of contemporary energy assisted liposuction technologies, like Renuvion®.
