The request for an effective method, with little to no downtime, to treat laxity on the aging neck and face is still in demand by today’s aesthetic patient. Fractional laser resurfacing has been instrumental in the treatment of skin laxity and the aging neck and is today considered a standard for skin rejuvenation.1-2 Following the development of fractional technology with lasers, other energy sources were also used in fractionated patterns, such as radiofrequency (RF) and ultrasound. One of the limitations in treating the neck and face with fractional lasers is the risk of hyperpigmentation, particularly in ethnic and darker Fitzpatrick skin phototypes.3 Because RF energy is not preferentially absorbed by melanin and can be delivered through an array of insulated microneedles to precise depths that spare the epidermis, it has been explored as a treatment in rejuvenation protocols. Having insulated needles, except for the active tip, maximum thermal coagulative injury zones can be delivered to the targeted layers of the dermis while only slight mechanical injury is caused to the epidermis. As a result, patient downtime and recovery are minimized as are risks of hyperpigmentation. Here we report on the safety profile using this device on the face and neck with a case series of 35 patients treated at seven different aesthetic practices using fractionated RF energy delivered through insulated microneedles.
The study device used (INFINI, Lutronic, Inc., Burlington, MA) delivers high intensity focused bipolar radiofrequency energy in a fractional pattern through an array of insulated 200-micron diameter microneedles that are arranged in a 7 X 7 array (49 microneedles) with a total spot size of 10mm X 10mm. A new needle design with enhanced pin-to-pin transmission of RF energy between the 49 gold plated needles was used. Penetration depth of the microneedles can be controlled from 0.5 mm to 3.5 mm which allows for the creation of a latticework of focal RF injuries, thus customizing the treatment, which, in this case series, allowed use of the highest recommended energy settings. The delivered RF energy can be selected by adjustment of the power setting up to 50 Watts and exposure time from 10 msec to 1 second.
This safety pilot study was conducted under IRB approval and all subjects provided signed, informed consent prior to enrollment. Each site treated five subjects on the face and neck