*3.5.2 Complications*

The most common concern regarding the use of lasers in the subcutaneous area is the overheating of the tissue and subsequent burns and skin necrosis. It is

important to bear in mind that the injury came from the subcutaneous plane. Therefore, if any blistering occurs in the postoperative period it will definitely result in a full-thickness burn although initially it may appear as superficial one. Due to the scarring of the full-thickness burn, this has to be avoided at all costs.

#### **3.6 J plasma/renuvion assisted liposuction**

One of the newer entrants to the energy-based device market is Renuvion® (Apyx Medical, Clearwater, Florida), which is powered by helium plasma. Cold Atmospheric Plasma (CAP) in a highly reactive (partly) ionized physical state that comprises a mixture of physical and biologically active agents and thermal levels of varying degrees is used for this purpose. Through the interaction of the plasma beam (He) with the surrounding air (N2, O2) or the water in the tissue (H2O), cold plasma generates radical species. Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are understood to cause cell proliferation and cell death, while extreme amounts of reactive oxygen and nitrogen species can induce protein, lipid, and DNA apoptosis and damage. These interactions can lead to epigenetic changes at the cellular level [53].

The unique Renuvion energy—helium plasma and proprietary radiofrequency (RF)—allows for precisely controlled delivery of heat to tissue, with minimal thermal spread and rapid heating with near-instantaneous cooling in part aided by the cooling effect of helium gas under the skin (in subdermal applications), which allows for shorter duration of activation and, therefore, less diffusion of heat to the skin. For just a brief interval, it flows through the application site and then disperses, leaving very reliable, predictable results.

There is no net electrical movement across the body, so there is no return electrode needed.

The cold plasma effect is extremely localized, reducing collateral damage to healthy tissue surrounding it. With its reduced tissue spread, Renuvion uses nonconductive currents and limits direct injury, reducing the chance of direct and capacitative coupling.

In addition, Renuvion facilitates secure and efficient coagulation/ablation/incision of tissue with controlled accuracy when tissue is ablated and decreases fear of damage to healthy surrounding structures. The Renuvion thermal ablation zones are illustrated in **Figure 15** and contrasted with normal electrosurgical ablation zones based on current.

In a number of tissue types and contrasts with various instruments, the Renuvion helium unit has limited lateral and thermal spread depth and its tissue effect depth varies from no apparent effect to approximately 2.0 mm with a lateral spread varying from 1.0 mm to 4.0 mm overall diameter for normal use [54].

#### *3.6.1 Renuvion/J-plasma subdermal method of action*

The average body temperature is 37° and can rise to 40° with normal illness without permanent effect or damage to the body cells. However, when the cell temperature in the tissue exceeds 50°, cell death takes place in around 6 minutes. Cell death occurs when the temperature of cells in the tissue exceeds 60° instantaneously [55].

Between the temperatures of 60° and just below 100°, 2 simultaneous processes take place. Protein denaturation leading to coagulation is the first. The second is desiccation or dehydration, since the adipocytes lose water through the thermally damaged cellular wall. Intracellular water transforms to steam as temperatures rise above 100°, and tissue cells begin to vaporize because of the massive intracellular expansion that occurs. Finally, organic molecules are broken down into a mechanism called carbonization at temperatures of 200° or more.

*Use of Technologies to Improve the Liposuction Outcome Including Skin Texture and Form DOI: http://dx.doi.org/10.5772/intechopen.99947*

This carbonization leaves behind molecules of carbon that give the tissue a black and/or brown look. These heat effects of RF energy on cells and tissue will make it possible to use predictable changes to achieve beneficial therapeutic results.

Protein denaturation which leads to coagulation of soft tissue is one of the most commonly used tissue effects. Protein denaturation is the mechanism in which protein hydrothermal bonds (cross connections), are instantaneously destroyed and then easily reformed as tissue cools.

This step is followed by coagulation, which contributes to the formation of uniform clumps of protein commonly called coagulum. Inside the cellular proteins are altered but not killed in the coagulation process and form protein bonds that create homogenous, gelatinous structures. The resulting coagulation tissue effect is extremely helpful and is most widely used to occlude blood vessels and induce hemostasis.

One of the major proteins present in human skin and connective tissue is collagen. Collagen's coagulation/denaturation temperature is conventionally stated to be 66.8 C, although this can vary for various types of tissue [56].

Once denatured, as fibers shrink to one-third of their total length, collagen quickly contracts. However, the amount of contraction depends on the temperature and duration of the treatment. The hotter the temperature, the shorter the amount of maximum contraction treatment time required [57].

In medicine, this phenomenon of thermally induced collagen contraction by denaturation and coagulation of soft tissue is well known and is used in ophthalmology, orthopedic applications, treatment of varicose veins, and cosmetic plastic surgery procedures to produce beneficial results.

The use of thermal-induced contraction of collagen/tissue has recently been extended to minimally invasive procedures. Subcutaneous tissue coagulation results in the contraction of collagen/tissue that decreases skin laxity. The helium-based plasma technology of BMC's Renuvion (formerly branded as J-Plasma) has FDA approval for soft tissue cutting, coagulation and ablation.

The Renuvion device consists of a generator unit for electrosurgery, a handpiece, and a helium gas supply (**Figure 16**). RF energy is delivered to the handpiece by the generator and is used to energize an electrode.

A helium plasma is generated when helium gas is passed over the energized electrode, which enables heat to be applied to tissue in 2 distinct ways. First, through the ionization and rapid neutralization of the helium atoms, heat is generated by the actual production of the plasma beam itself. Secondly, because plasmas are very good electrical conductors, a portion of the RF energy which is used to energize the electrode and produce the plasma passes from the electrode to the patient and heats the tissue by passing current through the tissue resistance, a method known as Joule heating.

These 2 tissue heating sources give the Renuvion device some unique advantages for the purpose of coagulation and contraction of subcutaneous soft tissue during use as a surgical tool.
