The Effect of Topical Anesthetic Hydration on the Depth of Thermal Injury From the Plasma Skin Regeneration Device

Background and ObjectivesThe plasma skin regeneration (PSR) device delivers thermal energy to the skin by converting nitrogen gas to plasma. Prior to treatment, hydration of the skin is recommended as it is thought to limit the zone of thermal damage. However, there is limited data on optimal hydration time. This pilot study aims to determine the effect of topical anesthetic application time on the depth of thermal injury from a PSR device using histology. Study Design/Materials and MethodsPSR (1.8 and 3.5J) was performed after 0, 30, or 60minutes of topical anesthetic application. Rhytidectomy was then performed and skin was fixed for histologic analysis. Four patients (two control and four treatment sites per patient) undergoing rhytidectomy were recruited for the study. Each patient served as his/her own control (no hydration). A scoring system for tissue injury was developed. Epidermal injury, the presence of vacuolization, blistering, damage to adnexal structures, and depth of dermal collagen changes were evaluated in over 1,400 high-power microscopy fields. ResultsThere was a significant difference in the average thermal injury score, depth of thermal damage, and epidermal injury when comparing controls to 30minutes of hydration (P=0.012, 0.012, 0.017, respectively). There was no statistical difference between controls and 60minutes of hydration or between 30 and 60minutes of hydration. Epidermal vacuolization at low energy and patchy distribution of thermal injury was also observed. ConclusionTopical hydration influences the amount of thermal damage when applied to skin for 30minutes prior to treatment with the PSR device. There was a trend toward decreasing thermal damage at 60minutes, and there was no difference between treatment for 30 or 60minutes. The data suggest that application of topical anesthetic for a short period of time prior to treatment with the PSR device is cost-effective, safe, and may be clinically beneficial. Lasers Surg. Med. 46:127-131, 2014. (c) 2013 Wiley Periodicals, Inc.