Stuff Worth Knowing: SWL v URS in Pediatric Stones

Despite the effectiveness of SWL in treating pediatric stones (see: Pediatric Stones and Shockwave Lithotripsy by Cynthia Smith, MD)  the increasing use of URS in the pediatric age group is well documented. Should we be concerned by that trend?

According to a June 2019 Journal of Pediatric Urology* multi-institutional study of pediatric stone treatments, the answer to that question is “Yes.”

In their retrospective study of pediatric stone cases, these U. of Michigan and Medical College of Wisconsin authors compared “… stone clearance, 30-day emergency department visits, and the number of general anesthetics required per stone treatment ….” for children treated by URS or SWL. The need for retreatment was also measured. Their multivariate analysis accounted for age, stone location & diameter, pre-treatment stenting and provider volume. What did they find?

Of the 259 cases reviewed, 84 (32%) received SWL while 175 (68%) underwent URS. Stone clearance was obtained in 77% of SWL cases and 78.5% of URS cases. While 17.9% of SWL cases needed retreatment, 18.9% of URS did. SWL patients required fewer general anesthetics per treatment (1.2) than did URS patients (2.0). SWL children had fewer emergency room visits for infection than URS patients (0% vs. 5.1%) and for flank pain (3.6% vs. 10.9%). So, what did we learn?

This pediatric stone study reflects the same trend seen in the broader stone patient population: URS is used in over 65% of the cases. Yet just as in the broader population, this study reflects the higher complication rate of URS, the higher unplanned admission rates, and subsequent costs. In addition, the retreatment rates and stone clearance rates in children for SWL and URS are similar, but the child is exposed to additional risk with URS because of the general anesthesia differential.

The logical question to ask ourselves is “Why are we using URS instead of SWL?”

* Marchetti KA et al, J Ped Urol, 30 193-197 June 2019