The effect of stone mineral composition on the fragmentation of urinary calculi using lasers

The use of lasers in surgery has been common practice almost since their invention in the 1960s, however lasers are used for medical applications in many other areas including physiotherapy and urology. Urological applications of lasers are primarily associated with the fragmenting of impacted aggregations in the ureteric tracts a disease which affects as many as 3% of the population in certain groups. The use of lasers is of prime value where modalities such as ultrasound lithotripsy is either ineffective or is contra-indicated but the mechanism which leads to destruction of the calculus is not well known. Some calculi are more susceptible than others, with cisteine being most resistant to laser fragmentation. The authors have looked at the structure and composition of a number of different stones both from patients and `artificial´ stones pressed from the pure material. The authors have examined the role of stone composition on stone fragility at different laser wavelengths and pulse characteristics