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BACKGROUND:Shockwave lithotripsy (SWL) remains one of the most common surgical interventions for urolithiasis. However, meta-analysis has confirmed that for ureteral stones, SWL only offers a higher stone free rate than ureteroscopy (URS) in proximal stones less than 1cm. We evaluated the utilization of ureteral SWL within a 22-hospital mobile lithotripsy system.
METHODS: We retrospectively reviewed utilization of ureteral SWL within a statewide consortium of 22 hospitals sharing leased mobile lithotripsy. We specifically evaluated the size and location of all treated ureteral stones for the year encompassing October 2012 and September 2013. We used Pearson’s Chi square and Wilcoxon test to analyze categorical variables.
RESULTS:Out of 971 procedures performed, 207 (21%) were ureteral. The mean stone size was 0.606, SD+/-0.44 cm. There was no significant correlation between stone size and location. Of ureteral stones undergoing SWL, 32.3% were <1cm and either in the mid or distal ureter. 22.7% were less than 3mm. 17.3% of shocked ureteral stones were over 1 cm. One hundred four (50.2%) were <1cm proximal ureteral stones.
CONCLUSIONS: While the AUA guidelines specify that both URS and SWL are reasonable first line treatment for ureteral stones, their meta-analysis of stone free rates revealed that URS stone free rate is superior to SWL in all ureteral locations and size categories except for proximal <1cm stones. However, these sub centimeter proximal ureteral stones comprise only one half of ureteral stones treated by SWL in this large cross sectional review. With evolving mandates for outcome reporting and the emergence of Accountable Care Organizations, further evaluation of these practice patterns is warranted to reduce use of less effective treatments.