138
Monopolar Radiofrequency
Tissue Tightening
Elizabeth F. Rostan
Background
Noninvasive tissue-tightening technologies rely on laser or radiofrequency (RF) energy to deliver heat to tissue without damaging the upper layers of skin. This heating of the tissue results in mechanical and molecular changes to produce tightening of the skin. Immediately this heating produces collagen contraction, then subsequent wound healing leads to new collagen production and wound contracture. The upper layer of skin is protected most frequently with a cooling mechanism or by utilizing low energy. There are currently multiple devices that claim noninvasive tissue tightening.
The devices utilizing radiogrequency include monopolar RF (ThermaCool device by Thermage, Hayward, CA), combined diode laser/bipolar (Polaris device by Syneron Medical, Yokeam, Isreal), and combined vacuum/bipolar RF (Aluma device by Lumenis, Santa Clara, CA). Other devices use laser or broadband light sources to heat the skin and include broadband light (Titan device by Cutera, Brisbane, CA and StarluxIR device by Palomar, Burlington, MA), and long-pulsed 1064-nm Nd:YAG lasers (multiple manufacturers). The rest of this discussion will focus on monopolar RF skin tightening.
Technology
Monopolar RF tissue tightening was first introduced in 2002 as the ThermaCool device by Thermage, Inc. (Haywood, CA). It was the first device marketed for noninvasive skin tightening. The ThermaCool device, which has FDA 510K approval for the treatment of facial rhytids and more recently for skin tightening of eyelid skin and nonfacial areas, utilizes monopolar RF energy to heat deeper dermal structures leading to collagen renewal and tightening.
The ThermaCool device utilizes a capacitively coupled treatment tip as the active electrode which is used in conjunction with a return electrode that is placed at a distant site on the patient. This treatment tip is
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cooled with multiple small bursts of cryogen during each treatment pulse in order to protect the upper layers of skin while the deeper structures are heated. Activation of the treatment tip against the skin creates an electric field under the tip. Tissue resistance in the skin and subcutaneous tissues generates heat from radiofrequency energy. The depth of tissue heating is related to the dimensions of the treatment tip. The first-gen- eration treatment tips were 1.0 cm2 and 1.5 cm2 and produced tissue heating to a depth of about 2.5 mm. Newer 3.0-cm2 tips penetrate more deeply, while smaller tips designed for use on eyelid skin have a much more limited depth of penetration (Figure 138.1).
Patient Selection
The best candidates for monopolar RF tissue tightening are those with mild to moderate degree of skin laxity of the face and neck. All skin types can be safely treated. Patients with thinner skin or less adipose tissue achieve greater degrees of tightening than those with heavier faces. In evaluating patients, I use gentle pressure laterally on the areas of interest to determine the degree of movement of the tissue. In the evaluation of the cheek and jowl area, if the amount of tissue that can be moved easily with one’s fingertips is mild to moderate, then I feel the patient is an appropriate candidate for ThermaCool treatment. If the amount of lax tissue is very significant, such that a large amount of tissue would have to be excised during a face or neck lifting procedure, then that option is discussed with the patient. I do perform ThermaCool procedures on patients who I feel would benefit more from a surgical procedure in instances where the patient states he or she has no interest in surgery at all or if there are medical conditions that make the patient a poor candidate for surgery.
In evaluating candidates for ThermaCool procedure of the forehead, I again like to be able to detect fairly significant tissue movement when pushing up on the skin of the forehead toward the hairline. If there is minimal movement or if the tissue feels very tight, do not recommend RF treatment for browlifting. If I can’t move the tissue with physical pressure, then RF treatment is not going to be able to move the tissue either. The lifting achieved with ThermaCool treatment in the forehead area is not as longlasting as other areas. Botox relaxation of the brow depressors is performed in most patients who elect to have RF treatment of the forehead area in order to remove the antagonistic effect of these muscles.
RF treatment of the eyelid skin is a new treatment with limited experience. A recently published study demonstrated that some patients, despite having as many as 700 pulses of RF energy, had no demonstrable improvement in eyelid skin laxity. For RF treatment of the eyelids, I prefer patients with mostly excess thin, loose skin to a mild to moderate degree. Patients with heavier eyelids require more significant fat pad resection in a blepharoplasty procedure.
For RF tissue tightening of the neck, the ideal candidate has mild skin laxity and no signifi cant laxity or platysmal muscle bands (Figure 138.2).
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It is recommended that treatment of the neck be combined with that of the cheek, as tightening of the cheek tissues often reduces neck laxity. If there is significant adipose tissue in the neck along with loose skin, I recommend that RF treatment be done immediately following tumescent liposculpture of the neck. This combination treatment is performed in patients who may have some skin laxity remaining after liposculpture alone. Again, monopolar RF tissue tightening will not replace a surgical procedure for those patients with significant skin laxity. I do not observe any tightening of loose platysmal bands after RF treatment. This should be clearly explained to patients prior to treatment.
For RF treatments on nonfacial skin, the most commonly treated area in my practice is the lower abdomen. I sometimes combine RF with tumescent liposuction in this area in surgical patients I judge to have excess skin that may be inadequately addressed with liposuction alone. The best candidates for RF tightening of lower abdominal skin are those with loose skin only and very minimal excess adipose tissue. This is typically seen in thin, fit women who have had children and have excess skin but otherwise tight abdominal structures. I do not commonly recommend treatment for other nonfacial areas (breasts, buttocks, thighs, arms) as I feel the results are inconsistent and often less than patient and physician expectations.
Realistic expectations are important for RF treatment of any area. The results typically are not dramatic and not well demonstrated by photographs. Sometimes the main aspect of improvement, especially in the cheeks, is how tight or firm the skin feels or that the skin resists gravity upon bending down.
Treatment
Current treatment protocols utilize multiple passes over the treatment area. Treatment grids with squares the size of the treatment tip are placed on the skin. This guides the placement of the tip during the treatment. Generally the grids are placed in the direction of desired tightening such as superior-lateral on the cheeks and vertical on the forehead. In most cases, at least one pass is applied over the entire treatment grid and then multiple passes (up to five) are performed over the areas of greatest movement or “lifting or anchor points” such as over the lateral cheek and zygoma and along the jawline to tighten the cheek and jowl area. In areas of loose skin the skin is kept taut with the nontreating hand so that the treatment tip is applied uniformly to the skin. When treating the forehead, I do not treat areas that do not move with pressure and instead focus on areas that are freely moveable.
Stretching the skin over certain anchoring points, such as pulling the lower cheek skin up to the zygoma, while applying the RF pulse can further enhance the tightening effect. Some physicians advocate pinching the skin in areas of excess adipose, such a heavy jowls or under the chin, and applying the tip to the pinched area. This is done in an attempt to cause deeper tightening and possible reshaping of fatty areas and
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should be used judiciously and only by experienced users. Pulse stacking is to be avoided as the heat build-up can lead to skin depressions.
Early experience with very high fluence demonstrated the risk of skin atrophy. Treatment settings are now more moderate and based more on patient tolerance and feedback. Many physicians give patients oral anxiolytics and/or oral or intramuscular narcotic pain medication prior to
RF treatment. General or IV sedation is not recommended because of loss of patient feedback regarding pain of the treatment. For the same reason, nerve blocks are not recommended. Topical anesthetics are used only numb the cooling sensation and do not help with the deep heat sensation. If topical numbing cream is used, then care should be taken to completely remove it prior to treatment as any residual on the skin surface is felt to increase the risk of a skin burn.
In the treatment of skin laxity of the upper and lower eyelid, a combination of tips is used. I first treat the brow, orbital rim, and temple area with a 1.0- or 1.5-cm2 tip. I also include treatment of the thicker upper eyelid skin just below the brow in this area. This skin is pulled above the bony orbit and the treatment tip only applied to skin overlying the bone. Then I treat the thin skin just above and directly overlying the globe and lower eyelid with the eyelid tip. A plastic eye shield must be placed prior to treatment. Metal eye shields should not be used during RF treatment.
Conclusion
Monopolar RF tissue tightening can be an effective, safe, nonablative way to achieve tighter skin in carefully selected patients. Results are modest and do not approach that achieved by surgery.
Figure 138.1.
Treatment of periorbital area with a 1.5-cm2 tip. The treatment tip is applied to thicker skin that is pulled over the bony orbit.
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Figure 138.2. Before and after neck treatment.
139
Dual-Mode Erbium-YAG Laser
Skin Resurfacing
John B. Holds*
Ablative laser skin resurfacing may give dramatic benefit in skin rejuvenation, although at the cost of significant risk, side effects, and healing time. Two lasers with significantly different physical effects but similar nal surgical results are employed: short-pulse CO2 and erbium-YAG (Er:YAG) lasers (Table 139.1). The absorption coefficient of water and tissue at the near infrared wavelength of the Er:YAG laser is 18 times that of the CO2 laser. For this reason, the Er:YAG laser at a short pulsewidth is almost purely ablative. The longer pulse duration and greater thermal damage in Table 139.1 for Er:YAG refers to lasers with a long pulse width coagulative mode. Moderate to deep chemical peels and dermabrasion can achieve results comparable to laser skin resurfacing in smoothing the skin and eradicating rhytids, with some similarities in
healing.
The short-pulse CO2 lasers were available first and are familiar to surgeons performing laser skin resurfacing. The Er:YAG lasers have been available for over 10 years, although the early lasers were underpowered and lacked both a thermal mode for deeper rhytids and a computerized pattern generator handpiece to achieve uniform application. There is a perception that Er:YAG lasers are only effective for fine wrinkles and will not treat deeper rhytids.
Multiple studies have documented CO2 and Er:YAG treatment to be equivalent or near-equivalent in facial laser skin resurfacing. Hughes1 noted the measurable skin contraction with Er:YAG skin resurfacing which progressed over 6 weeks of healing and persisted throughout the study. Khatri et al.2 noted significantly less prolonged postoperative erythema after Er:YAG treatment with a much lower risk (5% vs. 43%) of hypopigmentation, and Ross et al.3 noted equivalent results between Er: YAG and CO2 lasers when treated to equivalent depths.
For more than 9 years I have used a Sciton Contour dual-mode Er:
YAG laser that has not only a high power output (45 W) equal to the
*Dr. Holds has no financial interest in Sciton Corporation and receives no consultant or other fees from that company.
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