Plasma-mediated excimer laser ablation of bone: a potential microsurgical tool.

A pulsed ultraviolet excimer laser was used to ablate bone in vitro at 193, 248, 308, and 351 nm and in vivo at 193 nm. Ablation was dependent on sufficient fluence (energy delivered per unit area per pulse) for plasma formation at the target site at all wavelengths. Adjacent tissue damage at various fluences for each wavelength was examined using a light microscope. Damage was minimal at 193 nm (1 to 3 microns) and most extensive at 351 nm (60 to 75 microns). This is in sharp contrast to the 1 to 3 mm of adjacent thermal damage produced when carbon dioxide lasers are used to ablate bone. Differences in the degree and type of damage to adjacent tissues among the wavelengths studied indicated that other ablation mechanisms and tissue interactions are involved in addition to simple plasma vaporization of bone. Bleeding during and after ablation demonstrated that the use of this laser does not cause thermal damage, which would cauterize adjacent vessels. Pre- and post-mortem lesions made at identical power and pulse settings were of equal depth, indicating that bleeding does not affect the ablation rate. The excimer laser has potential as a microsurgical instrument for the precise removal of bone with minimal damage to adjacent structures.