Effect of extracorporeal piezoelectric lithotripsy shock waves on renal function measured by Tc-99m-DMSA using SPECT

Extracorporeal shock-wave lithotripsy has altered the therapeutic approach to urinary stone disease. Recently, a method was developed in which shock-wave generation is obtained piezoelectrically. To evaluate the effect of extracorporeal piezoelectric lithotripsy (EPL) on renal function, 20 patients were studied prior to and after EPL of renal calculi. Renal cortical function was evaluated by using a previously described and validated quantitative single photon emission computerized tomography (SPECT) method to measure individual absolute uptake of technetium-99m dimercaptosuccinic acid (Tc-99m-DMSA). Twenty kidneys were treated, and the 19 contralateral kidneys were without stone disease (1 patient had a single kidney). The absolute kidney uptake of Tc-DMSA in the normal kidneys was 21.4% +/- 6.2% before and 22.2% +/- 6.4% after EPL. For the treated kidneys the absolute update was 16.8% +/- 5.3% and 16.8% +/- 4.7% before and after, respectively. There was no statistical significant difference between pre- and post-treatment values. The absolute kidney uptake was significantly lower (p less than 0.01) in the treated than in the normal kidneys. This study indicates that the EPL procedure did not cause any damage to cortical function detectable by the DMSA uptake.