MP40-02 IDENTIFICATION OF NATURALLY OCCURRING CALCIUM-OXALATE BINDING PROTEINS IN HUMAN URINE THAT PREVENT CRYSTAL ADHESION IN AN IN VITRO MODEL OF KIDNEY STONE FORMATION

Abstract

INTRODUCTION AND OBJECTIVES: To identify factors affecting renal stone clearance after shockwave lithotripsy (SWL) in children and to assess the effect of tamsulosin as an adjunctive therapy after SWL in children. METHODS: One-hundred and twenty children below the age of 14 years with unilateral single renal pelvic stone were included in prospective randomized controlled study. Children with branched stone, solitary kidney, previous ipsilateral renal surgery, ureteral stent, or marked hydronephrosis were excluded. All children were randomized into two equal groups and all underwent SWL for their stones. Tamsulosin (in a dose of 0.01 mg/kg once daily) was prescribed for group (A) children as adjunctive therapy after SWL in addition to non-steroidal anti-inflammatory drug. Children in group (B) received non-steroidal anti-inflammatory drug only. Renal ultrasonography was performed 3 and 6 weeks after SWL. Stone clearance was defined as no renal stone fragments or <3mm and no pelvicalyceal system dilation. Children underwent a second session of SWL if there were residual stone fragment(s). Multivariate analysis was used to identify factors affecting single session stone clearance. Stone clearance rates in both groups were compared. RESULTS: Our study included 69 boys and 51 girls with median age 3.5 years and median stone size 1.2 cm. Stones were located in the right kidney in 72 children and in the left kidney in 48. KUB film showed that stones were radio-opaque in 82 (64 faint) and radiolucent in 38. Median stone density was 426 HU on non-contrast CT scan. There was no statistically significant difference between group (A) and group (B) regarding stone and children criteria. Ninety-nine (82.5%) children achieved stone clearance after the first session (50 in group A and 49 in group B). All children in both groups were cleared of stones after the second session. There was no statistically significant difference between single session stone clearance rates in either groups (p1⁄40.81). On multivariate analysis using logistic regression, tamsulosin intake as an adjunctive therapy after SWL had no statistically significant relation to single session clearance rate (p1⁄40.65). Smaller stone size (p1⁄40.016) and radio-opaque stones (p1⁄40.019) were the only significant factors. CONCLUSIONS: Stone size and radio-opacity are the main factors affecting renal stone clearance after SWL in children. Tamsulosin as an adjunctive therapy after SWL does not seem to improve renal stone clearance in children.