Evaluation of clinical, microscopic, and ultrastructural changes after treatment with a novel Q-switched Nd:YAG laser

Background: The Q-switched Nd:YAG laser was among the first non-ablative lasers to be used. High-fluence photoacoustic Q-switched laser treatments were shown to produce results akin to those seen with some ablative lasers. Previous low-fluence, non-thermal, Q-switched Nd:YAG lasers produced almost no results. Objective: The purpose of this study was to evaluate a new combined photoacoustic photothermal low-fluence Q-switched Nd:YAG laser in the treatment of facial photodamage. Methods: Ten individuals with photodamaged facial skin were enrolled in the study. Participants underwent six bi-weekly full-face treatments using a Q-switched Nd:YAG laser (RevLite, HOYA ConBio, Freemont, CA, USA) at 1064 nm, with an 8-mm spot size and fluence of 3.2 J cm2. Clinical improvement was evaluated through blinded investigator assessment of photographs obtained before and 3 months after the last treatment. Pre-auricular biopsies, performed before and 3 months following the last treatment, were processed for light and electron microscopy and analyzed for evidence of treatment-related changes. Results: Eight individuals completed the study with no serious or long-term complications. Blinded evaluator assessment documented improvement in a variety of different aspects of photodamaged skin. Biopsy specimens revealed changes consistent with wound repair under light microscopy, while electron microscopy confirmed new collagen deposition. Conclusion: A novel combined photoacoustic photothermal Q-switched Nd:YAG laser can be used for non-ablative photorejuvenation. In addition to clinical improvement, histological and ultrastructural changes consistent with new collagen deposition were noted.