Pediatric kidney: functional outcome after extracorporeal shock wave lithotripsy

We studied the efficacy, functional outcome and morphological changes following extracorporeal shock wave lithotripsy (ESWL*) of renal calculi in a pediatric population.

We prospectively evaluated 50 patients 2 to 12 years old (mean age 7.64) undergoing ESWL with the Siemens Lithostar Plus. Functional outcome was assessed by comparing total and ipsilateral glomerular filtration rates before and after ESWL. Glomerular filtration rate was measured using Gates' method on a 99mtechnetium-pentetic acid radionuclide renal scan corrected to body surface area times 1.73 m.2. Ultrasound was performed to assess morphological changes after ESWL.

The immediate fragmentation rate was 86% and the clearance rate was 82%. At the end of the study 40 patients were evaluable. Immediately after ESWL ultrasonography showed perirenal hematoma in 3 patients, intrarenal hematoma in 2 and subcapsular hematoma in 1. These changes resolved spontaneously at followup. There was no change in total or ipsilateral glomerular filtration rate at a mean followup of 31.7 months. Before and after ESWL total glomerular filtration rates were 86.58 +/- 12.43 and 86.27 +/- 12.82 ml. per minute per 1.73 m.2, respectively. Treated kidney glomerular filtration rate decreased insignificantly from 40.58 +/- 12.61 to 40.41 +/- 12.61 ml. per minute per 1.73 m.2 at 3 months. At the last followup the change in glomerular filtration rate was insignificant.

ESWL is effective in the pediatric population, and it can be safely performed without long-term bio-effects on the function or morphology of the growing kidney.