Abstract

Precise removal of soft tissues and bone is often necessary in surgery. Clinical cw CO₂ lasers are ineffective in cutting bone, yet efficiently ablate soft tissue. However, there is typically a 300–1000-jum zone of thermal damage left at the cut edge which impedes healing. A simple model predicts that short pulses of strongly absorbed laser radiation should efficiently ablate tissue and minimize residual damage. Studies were performed on guinea pig skin with pulsed CO₂ lasers (λ = 10.6 μm), the residual damage could be minimized to 50 μm when the pulse duration was less than the calculated thermal relaxation time for a layer one optical absorption length thick. At the peak of the water absorption curve, 2.9 μm, tissue absorbs 10 times more strongly than at 10.6 μm, and even less residual damage is possible; 100-ns Q-switched Er:YAG laser pulses (λ = 2.9 μm) ablated both soft tissues and bone; the zone of thermal damage was 5-10 μm. To compare healing, lesions were created in epilated guinea pig skin with Er:YAG and CO₂ lasers and a scalpel. Er:YAG laser wounds and scalpel wounds healed quickly and with the same minimal scarring, CO₂ laser wounds healed slowly with more scarring.

© 1987 Optical Society of America