Histologic Effects of Fractional Lasers and Energy‐Based Devices on Intradermally Injected Hyaluronic Acid Filler for Improving Skin Smoothness

ABSTRACT Background Prior studies have shown that energy‐based devices (EBDs) over pre‐injected hyaluronic acid (HA) fillers do not significantly affect clinical outcomes. However, the impact of EBDs over newly FDA‐approved HA filler for improving skin smoothness is still undetermined. Objective To evaluate the immediate histologic changes after various popular EBDs are performed over pre‐injected, newly FDA‐approved intradermal HA filler. Materials and Methods Abdominoplasty skin was injected with HA superficially. Zone 1 was used as untreated control, while the other zones treated with the 755‐nm picosecond laser with diffractive lens array, 1064‐nm picosecond and 1064‐nm Q‐switched lasers, radiofrequency with insulated microneedles, volumetric directional thermal impact ultrasound (VDTI), and thermomechanical fractional injury (TMFI) devices. Results Histology shows HA in the superficial to mid dermis. Treatment with fractional Q‐switched and picosecond lasers showed expected laser‐induced optical breakdown in the epidermis and dermis. RF microneedling, VDTI, and TMFI devices caused thermal damage of collagen bundles with dermal dehydration. Conclusion No immediate morphological changes to HA were noted following device treatment. However, the effect of heat‐generating devices on the molecular integrity of HA fillers, which are composed of HA and water, remains uncertain.