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

Abstract

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

Materials and methods: 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.

Results: 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.

Conclusion: 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.