Comparison of different encrustation severity scores for residual stone fragments after encrusted double J stent...

To evaluate the association between commonly used encrustation severity scoring systems and residual stone fragments following encrusted double-J stent removal.

Between January 2019 and January 2023, 1572 patients who underwent surgery for urolithiasis were retrospectively reviewed. Fifty-eight patients (3.6%) with encrusted double-J stents met the inclusion criteria. Patients were categorized into two groups based on non-contrast computed tomography findings four to six weeks after double-J stent removal: residual stone fragments (>3 mm) (n = 7) and stone-free status (n = 51). Encrustation severity was assessed using the Forgotten-Encrusted-Calcified (FECal) classification, Kidney-Ureter-Bladder (KUB) score, Visual Grading for Ureteral Encrusted Stent (V-GUES) system, and Encrustation Burden Score (EBS). Clinical variables and operative outcomes were compared, and predictors of residual fragments were analyzed using logistic regression analyses.

Baseline demographic and clinical characteristics were comparable between groups (all p > 0.05). Patients with residual fragments had significantly higher encrustation burden (p = 0.022) and longer operative duration (p = 0.034). V-GUES and EBS were significantly higher in the residual group (p < 0.001 and p = 0.022, respectively), whereas FECal and KUB scores did not differ significantly between groups. In univariate analysis, both V-GUES score (OR: 3.299, p = 0.019) and EBS (OR: 1.006, p = 0.032) were associated with residual stone fragments. However, no variable remained statistically significant in multivariate analysis, likely due to the limited number of residual stone events.

V-GUES score and EBS differed significantly between groups. Although both were associated with residual fragments in univariate analyses, these associations did not remain in multivariate models.