Basic Study of Neurotomy by Using Laser

Examination of The Kind of Laser and The Combination of Dye and Laser

Abstract

Last year, we proposed the new method of neurotomy by using laser. However, there appeared sometimes the problem that the power density at the tip of the optical fiber was high enough to carbonize the tissue around the tip of the optical fiber when the laser power was high enough to be obtained the total thermal degeneration of nerve fiber. In this study, in order to improve these problem, we examined the kind of laser and the combination of dye and laser. We selected argon laser that has a good absorption in tissue. And we selected indocyanine green (ICG), which has a good absorption in infrared area, to combine with infrared semiconductor laser. By using rabbits, the reaction of nerve fiber with argon laser and that with the combination of ICG and semiconductor laser were investigated pathologically. When using argon laser, the thermal degeneration in nerve fiber was observed with more than 200mW of laser power. However, the carbonization around the tip of optical fiber tended to be occurred. When using the combination of ICG and semiconductor laser, the thermal degeneration in nerve fiber was also observed with more than 200mW of laser power. In this method, the area in which dye was applied was heated up selectively, so it was considered to be useful method to realize the neurotomy by using laser.