Abstract
This study evaluates the pulsed tunable dye laser with wavelength 504 nm, frequency 10 Hz, and pulse width 1.2 microseconds for cholelitholysis. Power of 10-40 kW was directed through a 250-microns quartz fiber optic to ablate 55 gallstones (removed from 14 patients). The fiber was positioned in direct contact with the stones under saline. Power delivery was begun at 10 kW and increased in 10-kW increments until litholysis began. The range of power and energy necessary to fragment the gallstones was evaluated on four common bile ducts (fresh autopsy specimens). Following fragmentation, all stones were analyzed. There were 35 cholesterol stones (3 calcified) and 20 bilirubin stones (4 calcified). Size ranged from 0.012 to 7.56 cm3 (mean 0.96 +/- 1.41 cm3). Energy necessary for fragmentation ranged from 0.4 to 11.2 J (exposure time 1.0-28 s). Power necessary for fragmentation was 20 kW for 2/55 stones and 40 kW for 53/55 stones. At 40 kW (40 mJ/pulse), common bile duct perforation occurred within 1.1 +/- 0.1 s (0.44 +/- 0.04 J). The pulsed tunable dye laser can fragment gallstones of all compositions. The threshold for fragmentation is 40 kW, but common bile duct perforation occurs at this power. We conclude that laser radiation sufficient to fragment gallstones can injure the common bile duct.
Highlights
Fragmentation of common bile duct stones by a nonoperative or limited operative approach may be possible by directing a fiber optic into the common duct and delivering laser radiation
This study evaluates the pulsed tunable dye laser with wavelength 504 nm, frequency 10 Hz, and pulse width 1.2 ps for cholelitholysis
Laser radiation was kept constant once fragmentation was begun and laser delivery was continued until the stone was fragmented
Summary
Fragmentation of common bile duct stones by a nonoperative or limited operative approach may be possible by directing a fiber optic into the common duct and delivering laser radiation. This technique has been studied with the continuous wave neodymium-YAG laser ( 1064 nm),’ pulsed neodymium-YAG laser ( 1064 nm),*. Pulsed dye laser (450-700 nm),’ free electron laser (2.5-3.5 ~ m )copper , ~ vapor laser. Presented at the Sixth Annual Scientific Session of the Academy of Surgical Research, Long Beach, CA, September 27-29, 1990. Laser Fragmentation of Cholesterol Calculi Gallstones Volume (cm3) Energy
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