Editorial Comment for Matlaga et al.

This is a retrospective study, analyzing Medicare claims information, to compare resource utilization when either extracorporeal shockwave lithotripsy (SWL) or ureteroscopy (URS) is used as primary treatment for ureteral or kidney stones in this population. The results of the study are not surprising: SWL was used 74% of the time for renal stones and URS was used 80% of the time for ureteral stones.

Conclusions that can be drawn from the data analysis for this study are limited because information on stone size and specific stone location is not available. It is well established that the outcome (stone free and ancillary procedures) of a chosen treatment is dependent on stone size, specific location within the kidney (e.g., renal pelvis vs lower pole) or ureter (proximal vs distal), stone type, and stone size. As such, the number of ancillary procedures necessary may be related not only to the treatment modality chosen but also to the stone size and location. For example, it is likely that the urologist will choose URS for distal ureteral stones and SWL for proximal ureteral stones and the outcomes, including secondary procedures, are different based on ureteral stone location. There are other potential reasons for urologists to choose between SWL and URS regardless of the stone characteristics—comfort with flexible URS for proximal ureteral and kidney stones, financial interest as owners of lithotripsy machines, and other reimbursement issues.

As mentioned by the authors, the increasing cost of treating patients with kidney stones is a significant economic issue, and future Medicare reimbursement may be determined by a value driven system. In that context, the choice of stone treatment for a particular stone characteristic is likely to be determined by the treatment that is most efficacious the first time and necessitating the least number of secondary procedures.