The impact of pelvicaliceal features on problematic lower pole stone clearance in different age groups

Our aim was to evaluate the impact of pelvicaliceal variables in pediatric and adult age groups who underwent SWL for lower caliceal calculi.

25 pediatric and 78 adult patients treated with extracorporeal shock wave lithotripsy (SWL) between 1996 and 2004 were enrolled into the study after exclusion of patients with hydronephrosis, major renal anatomic anomalies, non-calcium stones, history of recurrent stone disease and previous renal surgery. Lower pole infundibulopelvic angle (IPA), infundibular length (IL), infundibular width (IW) and pelvicaliceal volume were measured from pre-SWL intravenous urography. The pelvicaliceal stone load (PSL) index implicating the stone burden of each patient described as the relationship between stone volume and total estimated pelvicaliceal volume for stone-bearing kidney was also calculated.

Sixty-eight percent of adult and 80% of pediatric patients became stone-free after SWL. The statistical insignificance between PSL index (p=0.097) of two groups shows that both groups shared a similar stone burden. According to SWL outcome, mean IPA values of stone-free and residual patients were 46.85 degrees and 30 degrees in pediatric group, respectively (p=0.01), whereas these values were 48.08 degrees and 43.06 degrees in the adult group, respectively (p=0.352). In the pediatric age group, stone-free and cumulative success rates increased with increasing IPA but this correlation was statistically insignificant (p: 0.263).

Lower caliceal anatomy has a higher impact on stone clearance after SWL in pediatric patients and urologists can expect better SWL outcomes from pediatric population with solitary lower caliceal stone than adults under the same conditions.