Two-Year Follow-up of Patients Treated with Extracorporeal Shock Wave Lithotripsy

Abstract

The two-year follow-up of patients treated with extracorporeal shock wave lithotripsy (ESWL) is reported with regard to factors enhancing a successful stone-free result, new stone recurrences, and the fate of residual fragments. Analysis of 1,910 patients evaluated three months following ESWL demonstrated that factors associated with an increased likelihood of a stone-free (SF) state were stone size less than 2 cm (79% SF), solitary stones (78% SF), stone location in the renal pelvis (84% SF), and the presence of normal renal anatomy (71% SF).

Renal calculi greater than 1 cm in diameter located in the lower pole of the kidney were more likely to require multiple ESWL treatments yet achieved lower stone-free rates than similar stones treated elsewhere in the renal collecting system.

New stone formation and the growth of residual fragments following ESWL were evaluated one and two years following ESWL. Overall, in patients becoming stone free following ESWL, recurrent (new) stones occurred in 8.4% of cases between three months and one year following ESWL and in another 10.6% of patients between one and two years following treatment. However, kidneys with residual fragments following ESWL were found to have fragment growth in 21.6% of cases between three months and one year following treatment (p < .001 compared to recurrent stone rate) and in 21.7% of cases between one and two years following treatment.