**3. RFAL adipose FSN contraction**

With the BodyTite RFAL applicators, BodyTite, FaceTite, AccuTite (and CelluTite internationally), RF flows from the small uncoated region of the 2.4 mm or 3.9 mm electrode, just proximal to the silastic cap and flows through the adipose tissue from the internal electrode to the external. Up to 70 watts of energy will be delivered automatically by the BodyTite workstation to ensure the most efficient and optimal rate

#### *Internal and External Radiofrequency Assisted Lipo-Coagulation (RFAL) in the Control of Soft… DOI: http://dx.doi.org/10.5772/intechopen.97378*

of rise of adipose temperature, which is 20 degrees Celsius/cm3/second. The external electrode moves smoothly along the surface of the skin, in tandem with the internal electrode in a bipolar configuration. The RF provides a strong ablative and coagulative effect on the adipose tissue, vascular tissue and the multi-directional Fibroseptal network (FSN) within 1 cm of the internal electrode, the temperatures are coagulative in intensity (70 degrees Celsius) with FSN and tissue contraction and adipose liquefaction (**Figure 10**). The FSN contracts optimally and maximally at 69 degrees Celsius [15]. At higher temperatures, that are prolonged, the chemical damage to the adipose tissue can result in fibrotic changes to the soft tissue. The RF flows from the internal to the external electrode is strongly ablative and coagulative within 1–2 cm of the internal electrode (**Figures 7** and **10**). As the RF current flows from the internal ablative tissue effect to the external electrode, which is much wider, the diameter of RF thermal heating increases, and the tissue heating becomes non ablative, gentle bulk heating when the RF reaches the external electrode. The smaller "relative" diameter of the 2.4 mm and 3.9 mm external electrode means a higher power density and more efficient RF flow and heating of the soft tissue and skin and temperature end points are achieved much faster than with the 1.2 mm FaceTite, which has the larger external electrode.

The BodyTite is used prior to or after performing SAL on those patients who:


#### **3.1 RFAL electrode geometry**

RFAL is intended for simultaneous coagulation of adipose tissue, blood vessels and sub-necrotic heating and contraction of the **soft tissue FSN** (Fibro-septal Network) matrix and, summatively, the subdermal space and dermal skin collagen (**Figure 13**). This technology combines some of the best features of surgical RF coagulators and non-invasive skin tightening devices. RFAL technology utilizes a geometry shown in **Figure 14**.

By slowly moving the RFAL applicators (AccuTite, Aviva, FaceTite and BodyTite) back and forth through the intended treatment area, uniform ablation and coagulation of adipose and vascular tissue and FSN is achieved. While the external electrode is always moved over the skin surface, the internal electrode should pass through the deep, intermediate and/or superficial fat layers to treat the adipose tissue between 1.5-5 cm. The internal electrode Lipo-coagulation, results in liquefaction of the adipose tissue, vessel coagulation of small venules and arterioles and stimulates the contraction and shortening of adjacent vertical, oblique and horizontal fibers of the FSN, or Fibroseptal network that connects the overlying soft tissue to the underlying muscle.

The hand piece of the RFAL device has a cannula/probe/electrode (internal electrode) with a conductive tip and external electrode with significantly larger surface area. Electrical current through both electrodes is the same but the *resistance for smaller electrode is much higher.*

#### **Figure 13.**

*The vertical, oblique and horizontal fibrous septa of the FSN is the vehicle for RF mediated contraction. The vertical, oblique and horizontal fibers act like "check rein ligaments" holding our skin to the underlying muscular fascia. Heating these fibers to 69 degrees results in contraction of up to 40% immediately. Over 6 months the entire soft tissue envelope remodels and demonstrates 25% contraction, which increases to 40–50% at 12 months and, if you add the Morpheus8 multi-level, multiple pass combination protocol 60–70% soft tissue contraction can occur. The reticular and papillary dermis will be heated, non-ablatively to between 36 and 42 degrees and will also deliver some horizontal soft tissue contraction.*

#### **Figure 14.**

*In the RFAL technology (and the Morpheus family of tips) the RF flows back and forth from the very small tip of an internal, silicone coated, positively charged "point type" electrode, which is placed in the deeper subcutaneous adipose, where the thermal effect is ablative, to a larger, negatively charged electrode that moves along the skin surface, in tandem with the internal electrode and creates a gentle, non-ablative bulk heating effect on the dermis (with the Morpheus, of course, the tip sits on the skin and is static during RF application).* *Internal and External Radiofrequency Assisted Lipo-Coagulation (RFAL) in the Control of Soft… DOI: http://dx.doi.org/10.5772/intechopen.97378*

Initial temperature of the patient body after tumescent anesthesia is about 28–30 degrees Celsius. Desired skin temperature is 38–42 degrees Celsius and required fat temperature is 68–70 degrees Celsius.

The desired thermal coagulative temperatures for adipose coagulation, FSN contraction and small venule and arterial coagulation is 70 degrees. The maximum thermal cut-off in the internal thermistor of the FaceTite and NeckTite is 70 degrees. As RF flows to the relatively large geometrical configuration of the external electrode, a gentle non-ablative, non-necrotic heating of the papillary and reticular dermis occurs with denaturation of the collagen occurs for remodeling and thermal tightening. This bipolar configuration allows the double benefit of internal FSN coagulation and contraction, as well as gentle trans-epidermal papillary and reticular dermal remodeling from the external electrode.

The InMode BodyTite, FaceTite and CelluTite user screen allows the physician user to set the cut-off temperature for the external epidermal monitored electrode as well as the internal coated electrode. The desired endpoint generally, internally is 70 degrees, while externally the desired cut off is between 36 and 42 degrees Celsius, depending upon the soft tissue laxity of the target soft tissue (**Figure 15**).

The silicone coated internal electrode prevents direct thermal stimulation and injury to the external access port and the silicone cap at the end of the FaceTite, NeckTite and BodyTite electrodes is bullet shaped, facilitating easy passage through soft tissue and minimizing the risk of end-dermal hits when going around a curved surface.

#### **3.2 RFAL safety monitoring**

One of the risks of any thermal treatment (laser or radiofrequency) is the possibility of a thermal skin injury [17]. Thermal treatment in subcutaneous or subdermal layers may create full thickness skin burn. Therefore, one of the most significant advances InMode has been able to develop and patent, are the contact, thermal, and impedance measurements and software algorithms of automatized RF cut-off feedback control that allow for the most controlled, effective and safest thermal delivery.

#### *3.2.1 Skin temperature measurements and the importance of sensing*

Non uniform treatment or over-heating the treatment area may result in the risk of unwanted thermal damage to the skin during the treatment. To avoid or minimize this risk of a skin burn, online real time thermal measurements are necessary. There are two basic methods of skin temperature measurements:


Advantages of IR thermometers is the speed of measurements and they do not need to be built into the device and are independent of the treatment. The obvious weakness of this method is collecting IR radiation from relatively large area which depends on distance from the measured area. You are also relying on a third party that is not linked in time of space to the thermal treatment being performed. Most importantly, you are not measuring the internal thermal profile.

A typical IR thermometer measured area is about 1cm2 or larger and allows you to monitor average skin temperature in treatment area but does not protect from

#### **Figure 15.**

*The InMode FaceTite and BodyTite physician treatment screen with the internal thermistor set to cut off at 70 degrees celsius and the external RF temperature cut off at 40 degrees celsius and the treatment time to 120 seconds. The real time temperatures on the right-hand side show the epidermal cut off temperature of 40 degrees and internally of 70 degrees have both be reached. The treatment time is allotted in renewable 120 second allotments (and FDA requirement) and, when the system indicates a time down, a simple release and the depression of your foot starts automatically another 120 seconds are allotted. The BodyTite workstations (FaceTite, BodyTite and CelluTite), release just enough energy to ensure the rate of rise of temperature is 20 degrees celsius/cm3/second. If the rate of rise of temperature is between 20 and 35 degrees celsius/cm3/second, the energy emitted from the system is automatically reduced to ensure the rate of rise is 20 degrees/cm3/second. If the rate of rise of temperature is >35 degrees celsius/cm3/second, the first of thermal injury is unacceptably high and the energy to the applicator is automatically interrupted and a low, flat audible will sound and you will see temperature Surg protection (TSP) on the screen. Simply take your foot off the pedal, re-position the applicator, put your foot on the pedal and begin treatment again. The exquisite safety feature (TSP) has just minimized the risk of the thermal injury.*

appearance of small hot spots that lead to the full thickness skin burns. The current "Standard of Care" would now be based upon the advanced on-board, built in InMode thermal, impedance and contact controls and not a third-party IR skin monitoring system. The synchronous and simultaneous measurement of internal and external thermal temperatures and cut-off targets, electrode contact sensing, high and low impedance sensing and rate of rise of temperature sensing and RF cut-off control is the "state of the art" InMode thermal control. All these "sensed" safety features are designed in the software to regulate the flow of RF to the emitting electrodes and is present on all the RFAL family of electrodes (BodyTite, FaceTite, AccuTite and Aviva), the external non-ablative RF devices (Forma, Plus, BodyFx, Evolve Tite, Evolve Trim and Evoke Jawline and Sub-mentum AND is present on the Morpheus Resurfacing and Remodeling tips. NOW that is one smart line of products!

These "sensed" features are measured through the engineering and insertion in each applicator and handpiece an elaborate array of thermistors and sensors and they consist of the following:

## *3.2.1.1 Internal and external thermal measurement*

Internal and external contact methods of thermal measurement allow the device and user to measure the temperature of small areas, both inside and

*Internal and External Radiofrequency Assisted Lipo-Coagulation (RFAL) in the Control of Soft… DOI: http://dx.doi.org/10.5772/intechopen.97378*

out. The internal thermistors are only on the internal minimally invasive RFAL applicators. The internal thermistor will measure the tissue temperature around the ablative internal tip of the electrode, while the external thermistor measures the skin temperature. The user can set independent internal and external cut-off temperatures that will automatically control the flow of RF energy to the internal electrode when the external and/or internal target temperature has been achieved. The disadvantage of this method is that the response time of the sensor is limited by thermal conductivity. Typical response times can vary by as much a 1 second. When the internal probe is moving quickly and in a uniform heated area the temperature response of the sensor is not sufficiently fast enough to monitor tissue temperature in real time and the clinical technique needs to be modify for slow and steady movements to ensure the most accurate thermal, contact and impedance feedback.

### *3.2.1.2 Rate of rise of temperature and temperature surge protection (TSP): Optimal safety and efficacy*

The InMode RFAL applicators and non-invasive RF handpieces also measure the rate of rise of temperature, each millisecond and which can help overcome the moving applicators and the thermal end point limitations mentioned above. The optimal rate of rise of temperature, as determined by in-vivo abdominoplasty specimen measurements is 20 degrees Celsius/cm3/second. The current InMode RF devices no longer allow the user to enter the RF energy, but rather, deliver just the right amount of RF power, to allow the rate of rise of tissue temperature to be 20C/cm3/second. When this rate of rise of tissue temperature is 20-35C/cm3/second, then the RF energy is reduced until the rate of rise is <20C/cm3/second. When the rate of rise of tissue temperature exceeds 35C/cm3/ second, then the RF energy is cut-off, the user hears a temp surg alarm and the user's foot must be released from the pedal and then re-applied to start the flow of RF again, which is enough time for the rate of rise of tissue temperature to drop below 20C/cm3/second.

#### *3.2.1.3 Contact sensing*

All InMode RFAL applicators and non-invasive RF handpieces have an external contact sensor and, if contact is broken between the external electrode and the surface of the skin, or is reduced significantly, but lifting the electrode partially off, the contact sensor will alarm and RF energy to the internal electrode will be cut-off. This contact sensing helps prevent arch burns or injuries.

#### *3.2.1.4 Impedance sensing and control of RF output*

The BodyTite RFAL system **(and Morpheus**) deploys a very sophisticated, online, Realtime impedance regulatory system to help control clinical circumstances where high thermal temperatures may occur. There are a several RFAL procedural situations when the contact sensing, external and internal tissue temperature and rate of rise of temperature measurements and RF energy control may require the additional of impedance measurement and control as well.

**Tissue impedance measurements** may improve procedural efficiency and safety of the treatment. Below are a few examples of how continuous, online impedance monitoring and control, in additional to external and internal thermal end point control, contact control and temperature surge protection control can prevent adverse effects.


Coagulation of tissue is often accompanied by tissue dehydration and carbonization and eschar will accumulate on the internal electrode, which will increase the impedance between the electrodes. When this occurs, the impedance will rise and the Impedance measuring system is adjusted to switch off RF power when tissue is dehydrated, and carbonization or eschar begins to occur near the internal electrode. That prevents eschar effect and increase efficiency of RF power delivery and save surgeon time. *It is also why you will never have to clean eschar off the internal electrode with the BodyTite RFAL system.*
