An analysis of the predictive factors for stone clearance at primary ureteroscopy

Ureteric colic is a common emergency urological presentation [1]. When operative intervention is required, retrograde ureteroscopy is the most common approach. There are multiple treatment strategies including primary ureteroscopy (URS), staged ureteroscopy, and deferred ureteroscopy following ureteric stent placement. The approach is based on a number of clinical and stone factors. This study assesses the factors which predict stone clearance at the initial procedure.

All patients diagnosed with an obstructing ureteric stone who were managed operatively in a consecutive 12-month period were included. Patients were evaluated for stone clearance following a single or multiple procedures. A number of factors including stone size, location, gender, age and pre-operative laboratory results were evaluated for association with stone clearance at index procedure. Multivariate logistic regression analyses were performed to produce odds ratios (OR) with confidence interval (CI) at 95% and significance values P < 0.05.

One hundred and seventy patients were included in the final analysis. Stone clearance following the index procedure was achieved in 57% (n = 100) of patients. Predictors of successful stone clearance at index procedure were stone size < 6 mm, male gender and distal stone location (p < 0.05). Proximal stone location, stone size > 10 mm and elevated c-reactive protein (CRP) were associated respectively with multiple procedures to achieve stone clearance (p < 0.05).

Acute ureteric stones can be managed with a number of treatment strategies. This study identifies factors which predict stone clearance at index procedure. These results will help urologists accurately counsel patients when undertaking operative management for ureteric colic.