Factors influencing computed tomography determined stone-free rates after ureteroscopy in real-world and its impact on retreatment rates at medium-term follow-up.

BACKGROUND AND OBJECTIVES

Residual stone fragments (RFs) following ureteroscopy increase the risk of reintervention. This study assesses stone-free rates (SFR) using non-contrast computed tomography (NCCT), identifies factors influencing SFR, and investigates the relationship between RFs and retreatment rates (RTR).

METHODS

Patients who underwent ureteroscopy for urolithiasis between September 2017 and March 2024 were included if they had postoperative NCCT. Exclusion criteria include nephrocalcinosis and combined intrarenal surgery. Clinical data, procedural details, and postoperative outcomes were analyzed. Univariate and multivariate Cox regression models assessed factors affecting SFR and RTR. A Kaplan Meier curve analyzed time to retreatment after surgery.

KEY FINDINGS AND LIMITATION

Among 457 patients (519 renal units) the true SFR was 42.8%, increasing to 58.4% and 78.6% when RFs < 3 mm and < 4 mm were included. Factors negatively associated with SFR included prior urolithiasis treatment, percutaneous nephrolithotomy, positive urine culture, prior stenting, larger stone size, and mid- or lower-pole stone location. Conversely, exclusively ureteric stones and single stones were associated with higher SFR. On multivariate analysis, positive urine culture, prior urolithiasis treatment, increasing stone size, and mid-pole stone location remained significant predictors of reduced SFR. Logistic regression revealed the odds ratio for RTR with RF > 3 mm versus RF < 3 mm was 7.14 (95% CI: 1.96-24.39). Limitations included the risk of missing some stone-related outcomes during follow-up.

CONCLUSIONS AND CLINICAL IMPLICATIONS

The NCCT determined true SFR was 42.8%, with the size of RFs strongly correlating with the RTR. Patients with residual calculi should be counselled about increased risk of retreatment rate.