Laser lithotripsy of gallstones: alexandrite and rhodamine-6G versus coumarin dye laser: fragmentation and fiber burn-off in vitro

摘要

Abstract: In the following study three different pulsed laser lithotripsy systems were compared for the fine fragmentation of identical sets of natural and synthetic gallstones `in vitro.' Using a pulsed coumarin dye laser (504 nm), a pulsed rhodamine 6G dye laser (595 nm), and a pulsed Alexandrite laser (755 nm) a total of 184 concrements of known chemical composition, size, and weight were disintegrated to a fragment size of $LSEQ 4 mm. To investigate the transferability of the results to stones of strongly varying sizes and weight, 64 concrements (7.2 - 20.1 mm/0.10 - 2.80 g) from three human `gall stone families,' were fragmented at constant laser parameters. All stones could be reliably disintegrated using the three laser systems at the different settings tested. Even though in our experimental set up the rhodamine 6G dye laser showed the best results, theses were not statistically significant to results obtained with the coumarin dye and the Alexandrite laser at high pulse energies. The mean fiber burn-off of the Alexandrite laser at 80 mJ (Do80:195 mm/cm$+3$/ stone vol.) was however 5 to 81 fold higher than with all other laser systems, a fact of clinical relevance as far as possible side effects of the quartz material in the bile duct are not yet known. !2