Comparative Measurements of Erbium-, Holmium-, and Thulium-Lasers in Meniscus and Bone Tissue

Near-infrared lasers at 2um (Thulium, Holmium) and 3um (Erbium) have much smaller penetration depths in tissue than the well-known Nd-YAG laser at 1.06um. Therefore they are suitable for cutting hard tissue as, e.g., meniscus and bone. We compare cutting efficiencies in air and water and analyze the effects of laser radiation on tissue macroscopically, by light and scanning electron microscopy. Highest ablation rates are obtained with the Erbium-YAG laser: 90um/pulse in bone and 630μm/pulse in meniscus, at the same time it causes the smallest necrotic zones of 3 0um. Minimum necrotic zones require ablation in water for all lasers investigated. SEM pictures also prove superiour properties of the Erbium-YAG laser with its minimum penetration depth compared to Thulium- and Holmium-lasers.