Failure after shockwave lithotripsy: is outcome machine dependent?

To investigate the issue of shockwave lithotripsy failure by studying the effect of machine crossover to the Technomed Sonolith Vision (TSV) lithotriptor in patients with previously unsuccessfully treated renal stones with the Dornier Compact Delta (DCD). Records were examined for the period between 1998 and 2006. Parameters analysed were: size, multiple/single stones, location, treatments/stone.

Seventy-six patients fulfilled the inclusion criteria. Following lithotripsy with the TSV, the stone-free rate (SFR) at 3 months was 56.7%, and the success rate (stone-free and fragments < or = 4 mm, SR) 86.7%. Twenty-two patients had multiple stones and the majority of the stones were located in the lower calyx (59.2%). Mean size was 8.9 mm prior to treatment with the TSV machine (10.2 mm for DCD). Further analysis followed in a subgroup of 42 patients of the same stone size (+/-2 mm) before and after DCD sessions. Mean stone size was 7 mm. The SFR was 61.9% (62.9% vs. 40.9% for single and multiple stones), and the SR was 88.1%. No difference in SFR was found for single or multiple stones in any of the two groups.

The term 'extracorporeal shockwave lithotripsy (ESWL)-resistant stones' needs to be re-examined, as treatment with a different lithotriptor was successful in a group of stones where another machine had failed. Lithotripters with different shock wave characteristics may result in difference in the results of ESWL. Future research in ESWL should focus on stone characteristics and development of machines with the ability to adapt to specific stone features.