HOLMIUM-YAG LASER FOR GALL STONE FRAGMENTATION - AN ENDOSCOPIC TOOL

A systematic review of the 2.1 mu holmium-YAG laser for gall stone lit hotripsy was undertaken. This infrared laser, which can be used endosc opically and percutaneously, has safety advantages over other lasers a nd has potential as a general purpose vascular and surgical tool. Twen ty nine gall stones (mean mass 1.3 g) were fragmented in vitro using p ulse energies of 114 to 159 mJ/pulse at 5 Hz with a 0.6 mm fibre, whil e being held in an endoscopy basket. All stones were successfully frag mented, requiring an average of 566 pulses with a 5 Hz pulse repetitio n frequency. The number of pulses required increased with gall stone s ize and mass (p < 0.01), and decreased with both pulse energy (p < 0.0 1) and operator experience (p < 0.05). The biochemical content of the stone did not significantly affect the number of pulses needed. The po tential hazard of the laser to the biliary endothelium was investigate d. At the pulse energies used, five pulses at close contact penetrated into the serosa of fresh gall bladder wall. No damage was seen when t wo pulses were fired. This laser shows considerable promise in gall st one lithotripsy. Until further safety data are available, however, its use with endoscopic vision is advised.