Basic Experimental Study for CO₂ Laser Microsurgery

Abstract

For the operation in neurosurgical field, CO₂-laser Combined with operating microscope is quite useful, especially for the excavation of hypervascular tumors, firm consistent tumors and deeply seated tumors. It seems to have boundless Potentiality in the neurosurgical operation in future. And for the progression of micro-laser surgery, accumulation of the basic studies are indispensable. We have used CO₂ surgical-Laser. Model 400 from Coherent Company in U. S. A. and the effect of the CO₂-laser beam on the brain under various conditions were investigated. Moreover, we created benign tumor like mass-lesion on the rabbits brain using its temporal muscles. The effect of the laser beam on this mass lesion was also investigated and the discussion about the way of laser irradiation was done.
1 The thermal damage was related with time, but it seemed relatively independent from the strength of the out-put power. The depth of evaporated crater seemed to be corresponded with both of exposure time and out-put power.
2 Under the ischemic condition, the thickness of the thermal damage was slightly lesser.
3 Under the hypertensive condition, the thermal damage was significantly increased. This result suggest the importance of the control of blood pressure during and post operative period.
4 Even if the brain tissue get damage by laser beam, morphological change does not necessarily follow immediately after the exposure. We noticed remarkable brain tissue damage and blood-brain-barrier destruction at late phase.
5 The effect of the laser beam on the brain of alive animal, seemed to be relatively complicated and it might not correspond with the result from removed brain or other organs. The main effect of the laser beam is undoubtly heat, but the brain damage might be affected by other conditions.
6 As a model of benign cerebral tumor, temporal muscles were attached to the brain surface. CO₂-laser beam was irradiated on this mass lesion, and the discussion was done about the best way of laser irradiation.
7 Accumulation of the basic studies are needed to progress “micro-laser-surgery”, especially when the procedure will be applied in the area close to important vital organs, such as brain stem and others.