IN-VITRO GALLSTONE LITHOTRIPSY WITH A PULSED DYE-LASER - IMPLICATIONSFOR CLINICAL-APPLICATION

This in vitro study analyzes the fragmentation of biliary calculi usin g a pulsed dye laser while attempting to reproduce conditions encounte red in the clinical setting. In an initial experiment using 87 calculi , increased firing frequency decreased the number of pulses needed to reach satisfactory fragmentation (fragments of only 5 mm in diameter o r less). An increase in pulse energy resulted in improved fragmentatio n efficacy with an optimal pulse energy of 60 mJ. Fifty-three stones w ere then fragmented using a pulse energy of 60 mj at a firing frequenc y of 2 Hz to analyze the stone dependent parameters of fragmentation. An average of 153 +/- 177 pulses was required for calculi to fragment into at least two large pieces (stone disruption). Satisfactory fragme ntation was achieved in all but four stones (mean: 781 +/- 461 pulses administered over 391 +/- 230 seconds). Decreasing stone diameter or w eight and an increasing bilirubin with a decreasing cholesterol conten t correlated significantly with the more rapid achievement of satisfac tory fragmentation (p < 0.05). Pulsed dye laser therapy produces stone disruption efficaciously and rapidly thus permitting its application to fragmentation of bile duct stones and their subsequent extraction t hrough a sphincterotomy opening. The achievement of fragments 5 mm and less, which would be relevant to gallbladder stone percutaneous extra ction, is time consuming, and limited by stone number, diameter and ch emical composition.