The Significance of Trans-Epidermal Water Loss After Microneedling and Microneedling-Radiofrequency Procedures: Histological and IRB-Approved Safety Study

Background Microneedling (MN) and microneedling-radiofrequency (MN-RF) result in skin rejuvenation and skin exposure to pathogens. Objectives The aim was to determine histopathological changes of needle-depth injuries in preauricular skin and measure time-dependent repair of transepidermal water loss (TEWL) in subjects. Methods MN and MN-RF procedures were performed at 0.5- and 1.5-mm needle depths on preauricular skin strips from a facelift patient. In 10 subjects, MN and MN-RF procedures were performed at 0.5-mm needle lengths on 6 marked opposing face and body sites. MN and MN-RF at 1.5-mm needle lengths were also carried out on each subject’s midface skin lateral to the nasolabial fold. TEWL measurements were recorded with a calibrated DermaLab Cortex device (Hadsund, Denmark). Results Histological examination confirmed that the penetration depths of microchannels closely approximated the 0.5- or 1.5-mm needle lengths. In addition, MN-RF exhibited zones of coagulation injury at the distal end of the channel. After MN or MN-RF at 0.5-mm needle length, TEWL values were greatest immediately after needling to scalp, midface, neck, chest, arm, and thigh sites and remained slightly higher than baseline throughout the 48-h evaluation period. TEWL measurements after MN or MN-RF at 1.5-mm needle length resulted in the highest- and longest-lasting values throughout the 2-day observation period. Conclusions MN and MN-RF devices are novel devices that require further investigation into optimal treatment parameters and protocols, patient selection, and protection against intrusion of external pathogens and reactive cosmeceutical ingredients with barrier repair. Level of Evidence: 2