Pain in extracorporeal shock wave lithotripsy.

Pain tolerance has long been identified as a factor influencing successful treatment of renal calculi by shock wave lithotripsy (SWL). We aimed to clarify which factors directly influence pain tolerance to predict which patients are likely to undergo successful treatment. We analysed retrospectively 179 patients who received their first SWL for a solitary kidney stone. All patients were on a non-opioid analgesia protocol and were treated on an outpatient basis. The target was to deliver 4,000 shock waves at an energy level of 4. In total, 53% of patients could tolerate the targeted shock wave number and energy and were retrospectively allocated into group A. Those who required a reduction in either energy levels or shock wave number were allocated in group B. Multivariate and univariate analysis showed that female patients, who are young with thin body habitus, have lower pain tolerance to SWL.