Optimizing pediatric shock wave lithotripsy: stepwise energy escalation vs. conventional fixed energy

Abstract

Background – Pediatric extracorporeal shock wave lithotripsy (ESWL) is widely used, but the optimal energy-delivery strategy remains uncertain. Adult data suggest that stepwise energy escalation may enhance fragmentation and limit tissue injury; pediatric evidence is limited. Methods – We conducted a single-center retrospective cohort of 81 children treated with ESWL using either a stepwise energy protocol (n = 41) or a conventional fixed-energy protocol (n = 40). The stepwise protocol began at 10 kV with 1 kV increases every 250 shocks up to 13 kV (maximum 3, 000 shocks per session); the conventional protocol used a fixed 13 kV. Primary outcome was 3-month stone-free status, defined as no visible stones on follow-up imaging, excluding fragments ≤3 mm. Secondary outcomes included stone-free status after the first session, number of sessions, auxiliary procedures, and complications. Results – After the first session, stone-free status was observed in 73.2% (30/41) with the stepwise protocol vs. 55.0% (22/40) with the conventional protocol. At 3 months, rates were 95.1% (39/41) vs. 87.5% (35/40). When fragments ≤3 mm were considered clearance, overall rates were 97.6% (40/41) vs. 95.0% (38/40). More children achieved clearance in a single session with the stepwise protocol (30 vs. 22). Auxiliary ureteroscopy was required in 1 vs. 2 cases. Only minor, self-limited events (hematuria, transient pain/colic) were reported. Conclusion – Stepwise energy escalation was associated with numerically higher clearance and fewer sessions than fixed-energy ESWL, without added morbidity. Prospective multicenter studies are needed to confirm these findings.