Skin laxity remains the Achilles’ Heel because of unrelenting assault from chronological hereditary factors and undue exposure to solar radiation and cigarette smoking. Appropriate patients for non-surgical tissue lifting and tightening include those who are apprehensive of surgery, have major health issues, experience post-op skin relapse, or have financial concerns associated with major invasive procedures. Realistic non-surgical options are almost always based in heat-induced changes to these tissues by light, ultrasound, or radiofrequency energy. Although outcome-limitations exist, such procedures have become accepted today because of improved criteria for patient selection, technological advancements, combination therapeutic approaches, and reduction of downtime.
Proposed Mechanism (s) of Thermal Actions
Thermal devices target tissue fluid (water) and collagen for heat absorption. Because collagen is surrounded by tissue fluid, appropriate temperature delivery of 65° C shrinks (denatures) the its triple helical configuration to become shorter resulting in tissue contraction. After the heat-modified tissues undergo remodeling, increased collagen production and deposition occurs with the skin dermis. According to the Arrhenius equation, that describes mathematically collagen denaturation, the degree of collagen contraction depends on the duration of heat exposure as well as the absolute temperature delivered. Probably, other significant factors, that are not fully understood, contribute to the final results.
Light-Based Devices
Although light-based treatments have been shown to result in collagen denaturation and remodeling, correlation with remodeling with clinical end-points has been variable. The principle of laser and other light devices is based on the term “selective thermolysis,” which states that the selected wavelength (nanometers) must be more strongly absorbed by the target tissue (chromophore) than the surrounding tissues. In addition, the amount of absorbed thermal energy must not only exceed the heat threshold of the target tissue to achieve the therapeutic goal, but also the time for the target tissue to lose 50% of the delivered energy must exist for safety reasons. Manufacturers must incorporate these factors in FDA-approved laser and other light-based devices for patient safety and effectiveness. Today fractional ablative devices have been designed to deliver microfractional energy to reduce down-time, pigmentary changes, and other side effects.
Ablative devices with CO2 or Er:YAG energy have demonstrated collagen contraction and remodeling with accompanying tissue tightening and wrinkle reduction. Although these lasers are very efficient in a limited degree of skin tightening, the risk of adverse effects have been reduced by improved laser design, delivery, patient selection, and provider experience and training. That being said, prolong redness, pigmentary changes, infection and irritation and scarring may still occur.
Non-ablative laser and broadband light devices, ranging from 532 to 1540nm wavelengths, including intense pulse light (IPL) were developed to reduce both risk of adverse events and downtime associated with ablative devices. Although these devices were designed to deliver their thermal energy into the dermis for collagen denaturation and “by-pass” the epidermis, the safety and efficacy are dependent on the applying the same criteria as selected in the use of ablative devices.
Ultrasound Devices
The use of ultrasound energy to selectively treat either the upper dermis, mid-dermis or subdermal levels to non-invasively lift and tighten skin above the brow, chin, neck and chest has become one of the most accepted ways for skin rejuvenation. Ultherapy™, the only FDA-approved ultrasound device, has been shown to micro-denature (thermal coagulation points) and remodel old collagen, stimulate new collagen and elastin fibers to tighten skin and deeper structures for a natural appearance without surgery or downtime. This ultrasound technology allows the provider to see and treat, with the combined selection of threetransducers, the precise tissue levels for a customized treatment, as a radiologist would look by ultrasound diagnosis for tissue abnormalities. Some patients may experience slight redness and puffiness for a day and may experience mild to moderate temporary discomfort during treatment. Optimal results can be seen after 2-3 months once tissue contraction occurs with lifting and tightening of the brow, midface, neck and chest. Off-label treatments to other areas of the body, such as the underarm, abdomen, and thighs can be done with consultation by Dr. Sasaki and his Ulthera-certified registered nursing staff. Patients may repeat Ulthera sessions for continue maintenance therapy. As a consultant, Dr. Sasaki received one of the first Ulthera™ devices in the country (2008), published over 3 manuscripts on customizing treatments in over 1000 patients in his Device and Injectable Center, and has delivered teaching courses for over 10 years at the American Society for Aesthetic Plastic Surgery and at International Societies.
Radiofrequency (RF) Devices
Radiofrequency devices are an alternative to light-based and ultrasound systems to heat, tighten and lift dermal and deeper tissues by selective and precise alternating current flowing from the tip of an electrode to contacted tissue. In the direct current, the flow of electrons is in one direction, whereas in alternating current the direction of flow cycles back and forth as a certain frequency (MHz). In tissue, the thermal effects of RF devices depend on the tissue’s impedance to the flow and agitation of the electron particles in contact with the specific tissue. Unlike laser and light energy, RF current is not scattered by the tissue nor absorbed by the melanin density in skin. Thus, patients of all skin types can benefit from treatment to denature, modify, and contract old collagen and stimulate neocollagenesis.
RF devices are either monopolar (unipolar), bipolar, or both. In monopolar systems, current flows from an active electrode in contact with the treated area to a larger grounding pad position on skin far away from the active electrode. Most of the thermal energy is localized in the adjacent tissue just beneath the electrode. Monopolar RF energy was the first nonsurgical procedure developed for facial skin tightening. Bi-polar devices use two electrodes positioned at fixed distances from each other. Both electrodes are in contact with the area to be treated with alternating current passing between the two electrodes. In these devices, the level of penetrating depth is about half the distance between the electrodes. Dr. Sasaki will provide you an in-depth consultation to help you understand the benefits and limitations of the current tissue tightening devices. These devices have a definite place in Dr. Sasaki’s practice. Dr. Sasaki will discuss whether their use is optimal to achieve your goals, and if not, whether surgical or minimal-invasive techniques should be considered.
