Ureteroscopy now used more than shock wave lithotripsy for treating kidney stones

Atlanta-Ureteroscopy has overtaken extracorporeal shock wave lithotripsy (ESWL) as the treatment of choice for kidney stones, Canadian researchers recently reported.

At the same time, the need for ancillary treatments has declined but morbidity associated with kidney stone treatment has increased, said first author Michael Ordon, MD, who presented his findings at the 2012 AUA annual meeting in Atlanta.

Population-based evaluations to accurately assess trends over time in the use of different treatment modalities in the management of kidney stones have not been previously conducted. Instead, physician surveys or series from single centers have been the predominant methods used to document an increase in the use of ureteroscopy.

"Accordingly, guidelines have changed to recognize ureteroscopy as a first-line treatment option along with ESWL for ureteral stones at all levels," said Dr. Ordon, fellow in endourology and minimally invasive surgery at St. Michael's Hospital, University of Toronto.

Many centers, however, may lack the up-to-date equipment and technical expertise necessary to achieve these same excellent results, said Dr. Ordon, who worked on the study with Kenneth T. Pace, MD, and colleagues.

His group sought to evaluate population-based trends in kidney stone management as well as the effects of treatment trends and technologic advances on patient morbidity in the "real world," including the need for ancillary treatment. Through the use of administrative databases, the authors designed a population-based cross-sectional time series to measure the utilization of ESWL, ureteroscopy, and percutaneous nephrolithotomy (PCNL) over the past 20 years on patients in Ontario.

All patients who underwent treatment for a kidney stone in Ontario between July 1, 1991 and Dec. 31, 2010 formed the study population. Three main data sources were used: the Ontario Health Insurance Plan's physician claims database, the Canadian Institute for Health Information-Discharge Abstract Database, and the National Ambulatory Care Reporting System.

The three principal outcomes were treatment utilization, the need for ancillary treatment (defined as a repeat or ancillary stone procedure within 90 days of the index treatment), and the proportion of treatments that required hospital readmission or emergency room (ER) visit within 7 days of hospital discharge.

The study sample included 116,115 patients who underwent 194,781 kidney stone treatments (ESWL: 96,807 treatments; ureteroscopy: 83,923 treatments; PCNL: 14,051 treatments).

The use of ESWL decreased significantly over the study period, from 68.5% of all stone procedures in 1991 to 33.7% by the end of the period (p<.0001). During the same time, the proportion of stones treated with ureteroscopy increased significantly, from 24.6% to 59.5% of procedures (p=.0002). There was no significant change over time in the proportion of kidney stones treated with PCNL (6.88% in 1991 vs. 6.85% in 2010).

The proportion of procedures that required ancillary treatments declined significantly, from 23.1% to 15.3% (p<.0001).

"Most of this decrease occurred after 2004," said Dr. Ordon, when ureteroscopy became the most widely used procedure for the treatment of kidney stones in Ontario.

Of the three treatment modalities, the need for ancillary treatment was lowest with ureteroscopy.

^{Sharp increase in hospital readmissions}

Overall, the rate of hospital readmission increased significantly over the study period, from 7.27% to 10.8% (p<.0001), with this increase occurring mainly after 2004. Similarly, the percentage of ER visits increased significantly, from 7.11% to 10.5% (p=.0024). Further analysis is planned to better evaluate the increase in hospital admissions and ER visits over time. Specifically, Dr. Ordon said, "We plan to separate ER visits for non-urologic versus urologic causes to see if it changes the findings."

"Part of the influence over time [in Ontario] is that ureteroscopy became much more accessible, and so now a lot of the physicians in the community may not be offering [referral for] shock wave lithotripsy but rather offering ureteroscopy because that is something that they can provide and be reimbursed for," he said.