Influence of Size and Location of Renal and Ureteral Calculi on the Effectiveness of Extracorporeal Shock Wave Lithotripsy
Six hundred eighty-four single stones less than 3 cm in maximum diameter were treated by extracorporeal shock wave lithotripsy (ESWL) over a ten-month period. Anatomical distribution revealed the following locations: calyceal 44%, pelvic 32% and ureteric 24%. Seventy percent were 1 cm or less in maximum diameter, 26% were 1.1 cm to 2.0 cm, and 4% were 2.1 cm to 3.0 cm. Forty-four percent required pre-ESWL ureteric manipulation. Plain radiographs done three months post-ESWL showed 71% of kidneys to be stone free, 10% with residual sand, 14% with greater than 50% improvement, and 5% with no change. There were similar stone-free rates for calyceal and pelvic stones (70% v 67%) but the ureteric stone-free rate was higher (82%). When stone size was considered, the stone-free rate for pelvic and calyceal stones less than 1 cm was 72% and 74%, respectively, but the stone-free rate decreased to 63% and 60% when the stone was 1 cm to 3 cm. Similarly the stone-free rate for ureteric stones declined from 82% to 33% as stone size increased. This study confirmed that the initial stone size and location are important determinants of the effectiveness of ESWL.
KeywordsShock Wave Extracorporeal Shock Wave Lithotripsy Ureteric Stone Stone Size Urinary Tract Calculus
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