Histologic and clinical response to varying density settings with a fractionally scanned carbon dioxide laser.

Objective: An evaluation of the histological and clinical response to varying density settings (-10%, 0, and 10% overlap) with a fractionally scanned CO2 laser.

Study Design: Clinical and histological study evaluating abdominoplasty excised tissue for depth of penetration and width of tissue ablated with varying density and energy settings utilizing a scanned microsecond pulsed CO2 laser. These parameters were correlated clinically with patients treated with similar density settings.

Participants: Fifteen patients were enrolled with 5 patients in each group: group 1 (density 1 settings), group 2 (density 2 settings) and group 3 (density 3 settings).

Main Outcome: Histological differences of width and depth of tissue ablated with varying density settings and correlation with photodamage improvement clinically.

Methods: Six samples of excised abdominoplasty tissue were treated with increased energy and density settings and were evaluated histologically. Clinically, 15 patients with photodamage to the face were randomized to receive a fractional CO2 laser treatment with density levels ranging from 1 to 3.

Results: Microarrays of tissue injury were visualized with multiple areas of superficial to full-thickness epidermal thermal damage. As energy increased (90 W to 100 W), the width of basophilic coagulation of the subepidermal collagen increased. Increased density paralleled increased depth of penetration of subepidermal coagulation. Patient assessment of discomfort, erythema, edema, and satisfaction with the procedure was proportional to increasing densities.

Conclusion: A fractional CO2 laser produces photorejuvenation, erythema, edema and discomfort in proportion with the depth and extent of epidermal and subepidermal thermal damage.