Critical prospective appraisal of renal morphology and function in children undergoing shockwave lithotripsy and percutaneous nephrolithotomy.

PURPOSE

To assess the effect of shockwave lithotripsy (SWL) and percutaneous nephrolithotomy (PCNL) on renal morphology and function in children undergoing therapy for upper-tract urolithiasis.

PATIENTS AND METHODS

Fourteen patients less than 13 years of age with renal or upper-ureteral calculi who were found suitable for primary SWL or PCNL were evaluated for alteration of renal morphology and function after treatment. Of the 18 renal units treated, SWL and PCNL were performed in 9 units each. The average stone size was 880.2 mm2 (range 110-3800 mm2; median 660 mm2). All children underwent ultrasonic estimation of renal length and parenchymal thickness, 99m technetium dimercaptosuccinic acid (DMSA) and 99m Tc-ethylene dicystine (EDC) scintigraphy, and glomerular filtration rate (GFR) estimation prior to intervention and at 3 and 6 months of follow-up.

RESULTS

Extracorporeal lithotripsy achieved complete clearance in 8 renal units (88%), requiring an average of 6333 shockwaves and an average of 2.2 sessions per renal unit. The efficiency quotient was 42. Percutaneous surgery likewise achieved complete stone clearance in 88% of renal units, with three units requiring more than one tract. Mixed calcium oxalate monohydrate and dihydrate accounted for the majority of the stones. The mean preintervention GFR was 78.3 +/- 14.6 mL/min/1.73 m2 (median 82.5 mL/min/1.73 m2; range 54-98.6 mL/min/1.73 m2), whereas the mean GFR at 3 months was 78.95 +/- 14.4 mL/min/1.73 m2 (median 78.95 mL/min/1.73 m2; range 52-98 mL/min/1.73 m2). A marginal improvement of an average of 0.65 mL/min was noted. Split function EDC scans demonstrated improved drainage in five cases after intervention; the rest were unchanged. Preintervention DMSA scans revealed renal cortical scars in three children. None of the renal units had developed fresh scars at follow-up scans. None of the children developed new-onset hypertension, proteinuria, or alteration in renal size.

CONCLUSION

In the present study, pediatric SWL and PCNL were not found to cause adverse renal morphologic or functional alteration. Stone clearance resulted in marginally improved function and better drainage.