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.