The Ideal Interval Between Repeated Shockwaves Lithotripsy Sessions for Renal Stones: A Randomized Controlled Trial

Objectives: To assess the ideal interval between repeated extracorporeal shockwave lithotripsy (SWL) for renal stones. Patient and Methods: Eligible patients with a single renal stone ≤20 mm who required SWL were randomly assigned to one of three groups based on intervals between first and second sessions. Patients underwent the second session after 3, 7, and 14 days in Groups 1, 2, and 3, respectively. Tubular functions were assessed through comparisons of urinary execration of kidney injury molecule-1 (KIM-1), neutrophil gelatinase associated lipocalin (NGAL), and interleukin-18 (IL-18) with pre-SWL values, whereas glomerular function was assessed by comparisons of protein/creatinine ratio with pre-SWL and changes in ipsilateral renal function on isotope scans. Treatment success was assessed by noncontrast CT after 3 months. Results: All demographics of the 166 patients included in the study were comparable between the three groups. There were significant elevations of tubular biomarkers and protein/creatinine ratio after first and second SWL sessions compared with pre-SWL values ( p