Histologic Effects of Fractional Laser and Radiofrequency Devices on Hyaluronic Acid Filler.

[BACKGROUND] Hyaluronic acid fillers (HAFs) and energy-based devices are frequently used sequentially. However, the effect of using fractional devices directly over HAF is unclear.

[OBJECTIVE] To evaluate histologic changes after fractional laser and radiofrequency (RF) therapies applied over preinjected HAF.

[MATERIALS AND METHODS] Abdominoplasty skin samples were divided into 8 zones. Intradermal injections of HAF were performed to 7 zones with 1 zone as untreated control. Six of 7 HAF injected zones were then treated with the following devices: 1,540-, 1,550-, 1927-, and 10,600-nm fractional lasers, and fractional bipolar RF delivered through insulated and noninsulated microneedles. After treatment, biopsies were collected for H&E staining.

[RESULTS] Histology revealed HAF in the mid to deep dermis. Treatment with 1,540-, 1,550-, 1927-, and 10,600-nm lasers did not result in any morphologic changes of HAF, although thermal changes from 1,540- and 1,550-nm lasers were in very close proximity to the filler. The RF devices demonstrated thermal damage of HAF along the microneedle tracks.

[CONCLUSION] Hyaluronic acid filler is unaffected by fractional lasers in this model. Fractional RF devices, which produce deeper dermal penetrations, will cause thermal damage of HAF. Caution is advised in using microneedle RF over recently injected filler. Study limitations include use of nonfacial skin and lack of inflammatory response in an ex-vivo model.