摘要

Objectives: To review the efficacy and safety of microneedle radiofrequency fractional (MNRF) technology in the management of atrophic scars and striae Introduction: Microneedle radiofrequency fractional (MNRF) has been found to be very effective in reducing both atrophic acne scars and open pores. Unlike lasers, MNRF improves skin texture by producing heat through tissue impedance by generating a flow of electrons in an electromagnetic field. Since the impedance of the dermis is lower (due to the higher water content) than epidermis, the flow of current is greater in the dermal tissue leading to formation of a larger coagulative thermal zone as compared to the epidermis Materials / method: Fractionated radiofrequency creates a thermal injury zone that is pyramidal in shape unlike the conical thermal damage induced by ablative lasers. MNRF improves scars by delivering bipolar RF through a smooth electronically controlled insertion of insulated or Non insulated microneedles which can penetrate different depths of the dermis & create radiofrequency thermal zones (RFTZ) without causing epidermal injury. In addition, microneedles result in mechanical disruption of fibrotic strands responsible for causing the downward traction of atrophic scars. Results: The needles can be insulated or non-insulated. Insulated needles use insulation to cover the entire length of the needle, leaving only a small part of the tip conductive. Multiple passes are needed for treatment and there may be a tendency for micro bruising due to absence of coagulation along the length of the needle. Non-insulated microneedle RF takes advantage of the impedance difference between the epidermis and dermis. RF flows through all dermal layers at one time leading to a faster heating of the upper and lower dermis without any epidermal damage. Conclusion: MNRF usually requires 4-6 sessions for optimal results, with minimal adverse effects such as pain, erythema, oedema and spot bleeding. Pain is significantly lower as compared to ablative fractional lasers. Pain can be reduced by performing the passes quickly in order to reduce treatment time. The occurrence of scarring or pigmentary complications after treatment in the darker skin types is extremely rare as radiofrequency is a color-blind technology. Considering its efficacy and safety in type 3-5 skin, MNRF can be used as a first line treatment in all types of acne scars.