Predicting negative ureteroscopy for stone disease - Minimizing risk and cost

Urolithiasis is common worldwide, with ureteric stones being a particular burden. Ureteroscopy (URS) is one of the most useful procedures in treating ureteric stones not passed spontaneously; this procedure has a complication risk of 4%. Negative URS, with described rates up to 15%, represents an avoidable patient risk and use of medical resources.

To describe rates and identify predictive factors for negative URS and to define strategies which would minimize patient and financial burden from these unnecessary procedures.

A retrospective cohort study analyzed patients who underwent URS in our Center to treat ureteric stones over a period of 2 years. Patient age, gender, and comorbidities, as well as laboratory and imaging findings, were analyzed.

262 patients underwent URS for ureteric stones. The female population was 50.8% with a mean age of 56.89 years. A total of 78 (29.8%) URS procedures were negative. Univariate analysis showed a higher prevalence of negative URS in female patients, as well as in primary, smaller, and radiolucent stones. At multivariate analysis, a logistic regression model correctly classified 76% of patients, with smaller stone size and radiolucency being significant predictors of negative URS.

Our Center showed a high rate of negative URS, higher than commonly described in the literature. Female patients tend to have an even higher rate, possibly due to unnoticed passage of stones. Patients with small, radiolucent stones showed the highest rates of negative URS.