Quality assurance: monitoring lithotriptor output and its clinical implications.

Serial acoustic output measurements performed on the an electromagnetic lithotriptor consistently showed significant decreases in the output of the shock heads. A decrease in output during the lifetime of the shock head to less than 50% of its original output was observed. Decreased output was related to a higher number of shocks per treatment and a higher retreatment rate. Quality control of the lithotriptor output was reflected in better clinical results, a lower mean number of shocks per treatment, a lower retreatment rate and less time on the table, which has important clinical and financial implications. Acoustic output measurements on lithotriptors should be mandatory to achieve the best possible clinical results from extracorporeal shock wave lithotripsy.