Pilot clinical study of a novel minimally invasive bipolar microneedle radiofrequency device

Abstract

Background and Objectives: Noninvasive bipolar and monopolar radiofrequency (RF) deep dermal heating devices have previously been described. A novel minimally invasive RF device employing a bipolar microneedle electrode system is introduced and its resultant thermal effects on human skin in vivo were characterized for the first time. Study Design/Materials and Methods: An investigational 35 W RF device was configured to operate in bipolar mode delivering energy directly within the dermis using 5 microneedle electrode pairs with real-time feedback of tissue temperature for treatment control. Superficial cooling was achieved using a Peltier device. A range of pulse durations between 1 and 25 seconds, and lesion temperatures between 60 and 80 C were tested in vivo on 15 human subjects. Thermal effects were assessed histologically using either hematoxylin & eosin (H&E) or nitroblue-tetrazoliumchloride (NBTC) staining. Treatment effects and adverse events were also monitored clinically. Results: The investigational bipolar RF device delivered controlled heating within dermal tissue. Histological staining with H&E revealed the presence of zones of denatured collagen within the reticular dermis. Lesions were generated at preselected temperatures between 60 and 80 C. Fractional lesions separated by zones of sparing as well as contiguous lesion patterns were demonstrated. Histological staining with H&E and NBTC revealed sparing of adnexal structures and adipose tissue. No major adverse events were observed. Conclusions: A novel fractional RF device utilizing a minimally invasive bipolar microneedle delivery system for the treatment of human tissue was developed. Treatment of 15 human subjects illustrated the controlled creation of dermally located thermal coagulation zones, herein known as radiofrequency thermal zones. We discovered that varying the pulse length allowed for fractional sparing of dermal tissue. To our knowledge, this is the first report to describe use of a direct real-time temperature and impedance feedback system to control energy delivery during deep dermal heating. Lasers Surg. Med. 41:87--95, 2009.

Efficacy of Fractional Microneedle Radiofrequency Device in the Treatment of Primary Axillary Hyperhidrosis: A Pilot Study

“…Nevertheless, the final score was lower than the score of 3.5 at baseline, which suggests that FMR is effective in reducing the amount of sweat. Although we did not check tissue resistance exactly, tumescent anesthesia, which was used to reduce heat damage to the skin and to reduce pain during therapy, is presumed to decrease the effect of FMR treatment by altering energy deposition and heating patterns [23]. Therefore, even though topical numbing cream does not affect tissue impedance, because of the application of the topical cream, FMR could maximize heat delivery to sweat glands, which could lead to an augmentation of the effects of FMR on PAH when compared with botulinum toxin.…”

Consensus Recommendations on the Use of a Fractional Radiofrequency Microneedle and Its Applications in Dermatologic Laser Surgery

“…6,7 Hantash et al introduced a minimally invasive device, microneedle fractional RF, which adopted microneedle therapy system (MTS) for delivering bipolar RF energy directly into the skin through microneedle. 4 It generates fractional radiofrequency thermal zone (RFTZ) within the reticular dermis. 4 The FRM system is a minimally invasive nonablative RF device that delivers mono-and bipolar RF energy in the form of an electrical current that generates heat through the inherent electrical resistance of dermal and subcutaneous tissue.…”

“…4 It generates fractional radiofrequency thermal zone (RFTZ) within the reticular dermis. 4 The FRM system is a minimally invasive nonablative RF device that delivers mono-and bipolar RF energy in the form of an electrical current that generates heat through the inherent electrical resistance of dermal and subcutaneous tissue. …”

“…[1][2][3] Recently, combining the fractional technique with a classical nonablative radiofrequency device has been introduced and revolutionized the field of skin rejuvenation. 1,[4][5][6][7] Fractional radiofrequency micro-needle (FRM) system delivers an exact amount of RF energy at accurate depth directly into the deep dermal area through micro-needle. 1,[4][5][6][7] Although the use of FRM device has been examined and expanded by some clinicians, the exact parameters and guidelines have not been established.…”

“…1,[4][5][6][7] Fractional radiofrequency micro-needle (FRM) system delivers an exact amount of RF energy at accurate depth directly into the deep dermal area through micro-needle. 1,[4][5][6][7] Although the use of FRM device has been examined and expanded by some clinicians, the exact parameters and guidelines have not been established. In this article, concrete treatment recommendations for different dermatologic conditions and suitable techniques for pre-and after-treatment will be discussed.…”