Pediatric Kidney: Functional Outcome After Extracorporeal Shock Wave Lithotripsy

Abstract

Purpose We studied the efficacy, functional outcome and morphological changes following extracorporeal shock wave lithotripsy (ESWL*) of renal calculi in a pediatric population. *Dornier Medical Systems, Inc., Marietta, Georgia. Materials and Methods 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 99m technetium-pentetic acid radionuclide renal scan corrected to body surface area times 1.73 m. 2 . Ultrasound was performed to assess morphological changes after ESWL. Results The immediate fragmentation rate was 86 percent and the clearance rate was 82 percent. 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 plus/minus 12.43 and 86.27 plus/minus 12.82 ml. per minute per 1.73 m. 2, respectively. Treated kidney glomerular filtration rate decreased insignificantly from 40.58 plus/minus 12.61 to 40.41 plus/minus 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. Conclusions 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.