Radiology, Vol 174, 781-785, Copyright © 1990 by Radiological Society of North America
Gallstone fragmentation with contact electrohydraulic lithotripsy: in vitro study of physical and technical factors
GA Tung, PR Mueller, JA Brink, S Saini and JT Ferrucci
Department of Radiology, Massachusetts General Hospital, Boston 02114.
To identify physical and technical factors that have an effect on
fragmentation, the authors performed in vitro contact electrohydraulic
lithotripsy (EHL) on gallstones 10 mm or larger in size. Of 122 gallstones,
113 (93%) could be fragmented with 1-46 pulses from a 3-F electrode
(average, 10 pulses). Only 12 of the 113 stones could be fragmented with a
single spark. Of the nine stones that did not fragment with 50 pulses from
a 3-F electrode, four were larger than 30 mm in diameter, and five were
seen at radiography to be heavily calcified; all of these stones were
fragmented with five or fewer pulses from a 9-F electrode. Stone capture in
a wire basket facilitated fragmentation of gallstones of all sizes, but
particularly those stones 15 mm or larger. Contact EHL could be performed
as well in a 1:1 dilute diatrizoate irrigating solution as in 1:6 normal
saline. A significantly greater number of pulses was required to fragment
gallstones 15 mm in diameter or larger compared with stones smaller than 15
mm (P less than .01). In addition, stones 15 mm or smaller had a greater
tendency to fragment into "gravel" (ie, fragments measuring 2 mm or less),
while EHL of stones larger than 15 mm produced larger, discrete fragments
of approximately equal size (P less than .05). EHL of heavily calcified
gallstones required a significantly greater number of pulses than EHL of
less calcified or noncalcified stones (P less than .002).
