Effects of CO2 laser pulse duration in ablation and residual thermal damage: implications for skin resurfacing.

BACKGROUND AND OBJECTIVES: Resurfacing with the CO2 laser is rapidly gaining acceptance for skin rejuvenation. Advances in CO2 laser and scanning technology allow for precise tissue removal with minimal thermal damage. High energy CO2 laser pulses have been widely used effectively to smooth the surface of facial skin; however, pulse duration effects on ablation and thermal damage have not been systematically studied over the milli-second region (0.25-10 ms).

STUDY DESIGN/MATERIALS AND METHODS: This study characterizes the ablation threshold, heat of ablation, and residual thermal damage in skin resulting from CO2 laser pulses with a Gaussian beam profile. Mass loss from fresh pig skin was measured with an analytical balance, and residual thermal damage was determined through histology.

RESULTS: Pulse durations > 1 ms were associated with higher ablation thresholds and localized increased thermal damage.

CONCLUSIONS: Our results show that although pulse duration is an important determinant in ablation and thermal damage, irradiance is more critical as an independent parameter in predicting the effects of CO2 laser pulses.