1) We have already reported on drilling experiments of extracted urinary calculi by the use of laser beam.
2) As the second step, experiments using a CO2 gas laser guided through a manipulator which consists of three arms and mirrors, and also using a Nd:YAG laser guided through an optical fiber, was performed.
3) Some stones were not merely perforated but also disintegrated in a wet condition.
4) Although a CO2 gas laser was more effective than a Nd:YAG laser in the destruction of stones, an optical fiber combined with Nd:YAG laser was easier to handle than a manipulator combinded with a CO2 gas laser.
