TREATMENT GUIDE | Ablative fractional resurfacing was shown
to be superior to non-ablative fractional resurfacing in multiple comparative trials. On the other hand, the downtime of non-ablative resurfacing is shorter. The clinical results of fractional ablative
technologies are somewhat less impressive than that of traditional ablative methods, and multiple treatments are needed. These technologies have a very good safety profile when compared with traditional ablative resurfacing ® the downtime is shorter and the risk for complications is very low. On the whole, fractional technologies give the possibility to remarkably rejuvenate the skin with much less risk of permanent complications (scarring and hypopigmentation)4
.
Radiofrequency Radiofrequency (RF) differs from all other resurfacing technologies as it uses a high-frequency alternating electric current and not light or a chemical to rejuvenate the skin. The current frequencies range between 3 kHzÐ 300 GHz and heat is generated in tissue as a result of the natural resistance of tissue to the movement of electrons. RF energy is subject to OhmÕs law in which:
Energy (J)= I¨ (current) x R(resistance) x time.
The thermal effect on tissue depends
on electrode configuration, energy delivered, pulse mode and on tissue resistance to the current. RF technologies can be divided into
monopolar and bipolar RF technologies with variants in each group. In monopolar RF technologies, one electrode emits the alternating current and the other distant larger electrode serves as a grounding pad. The drawback of these technologies is that electric current passes through the body (depending on tissue resistance), and it is not known how the current will flow and spread. Non-ablative monopolar RF has been used since 2003 to rejuvenate and tighten the skin5
. References
1. Sidgwick GP, Bayat A. Extracellular matrix molecules implicated in hypertrophic and keloid scarring. J Eur Acad Dermatol Venereol 2012; 26(2): 141–52
2. Tziotzios C, Profyris C, Sterling J. Cutaneous scarring:
102 ❚
Pathophysiology, molecular mechanisms, and scar reduction therapeutics Part I. The molecular basis of scar formation. J Am Acad Dermatol 2012; 66(1): 1–10
3. Manstein D, Herron GS, Sink RK, Tanner H, Anderson RR. Fractional
photothermolysis: a new concept for cutaneous remodeling using microscopic patterns of thermal injury. Lasers Surg Med 2004; 34(5): 426–38
4. Smith KC, Schachter GD. Technical characteristics of
fractional light devices. Facial Plast Surg Clin North Am 2011; 19(2): 235–40
5. Elsaie ML, Choudhary S, Leiva A, Nouri K. Nonablative radiofrequency for skin rejuvenation. Derm Surg 2010; 36(5): 577–89
6. Zelickson BD, Kist D, Bernstein E et al. Histological and ultrastructural evaluation of the effects of radiofrequency-based nonablative dermal remodeling device. Arch Dermatol 2004; 140(2): 204–9
In bipolar RF technologies the current
flows between two electrodes that are applied to the skin and is limited to the area between the two electrodes. Therefore, less current is required to achieve the same effect and there is much more control over the flow of the current, as it will always stay in the area between the electrodes. When RF energy enters the skin, a large part of this energy will flow and spread through the dermis owing to the low impedance to current in the dermis. This overall spread of energy in the dermis will lead to Ôvolumetric heatingÕ of the dermis and later, to new ECM formation and tissue rejuvenation and tightening. It has been shown that heating the dermis by RF to 55–65 C gives immediate scattered shortening and thickening of collagen fibres and loss of their borders. This is owing to the breakage of the hydrogen bonds of the collagen triple helix and leads to immediate tissue contraction. These changes lead to collagen I mRNA elevation from days 2–7 and to neocollagenesis by fibroblasts. For 2–6 months after treatment, a gradual tissue remodelling response can be seen, leading to the desired tissue tightening effect6
. In contrast to light energy, RF energy is
not scattered, diffracted or absorbed at the epidermal level. Most of the energy reaches its target, the dermis. And, as no energy is absorbed specifically by epidermal melanin, RF energy can be used in the treatment of all skin types with a much lower risk than lasers or light sources for
post-inflammatory
hyperpigmentation (PIH). As with the light sources, RF
technologies can be ablative and non-ablative. In recent years, fractional ablative technologies have been introduced. Owing to the low resistance of the dermis, most of the energy flows there while epidermal ablation is minimal. These technologies are subablative or, as recently
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coined, ÔsublativeÕ. The downtime with these ÔsublativeÕ technologies is shorter than with the fractional ablative lasers and the risk for complication is very low. In a 12-week open-label study, the author
Ablative fractional
non-ablative fractional resurfacing in multiple comparative trials.
resurfacing was shown to be superior to
evaluated the efficacy of a bipolar fractional ablative RF (eMatrix, Syneron Medical Ltd). Ten female patients with moderate elastosis (mean grade 5 on the Fitzpatrick Classification of Wrinkling and Degree of Elastosis scale) entered the study and received five monthly treatments with a fractional bipolar RF device.
They all had a remarkable improvement in tightness, brightness, pores and luminosity after only two treatments, with continuous improvement after each subsequent visit. There was a mean 1.5-point improvement on the Fitzpatrick elastosis scale and patient satisfaction was very high.
Vascular/pigmented lesions
Conclusions For many years the main focus in skin rejuvenation was ablative resurfacing. It was considered by many to be the best way to improve the signs of ageing. The drawbacks of ablative resurfacing, including a long recovery time and the substantial risk for complications, have led to the search for other safe and effective treatment possibilities. With the advent of new technologies together with a better understanding of the wound healing process and the possibility to induce different forms of a controlled, more efficient and less vigorous wound healing response, we are now able to offer patients remarkable clinical results with less downtime and fewer complications.
Ines Verner is Dermatologist, President of
the Israel Society for Dermatologic Surgery, and Medical Director of Clinic of Dermatology & Aesthetics, Kiriat Ono, Israel
March 2012 |
prime-journal.com
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