Factors associated with digital flexible ureteroscopy management in kidney stone treatment: a prospective study.

BACKGROUND

Digital flexible ureteroscopy (FURS) has become a standard minimally invasive approach for treating renal calculi, yet evidence from Vietnam remains limited. This study evaluated treatment outcomes and identified predictors of stone-free rate (SFR) following digital FURS.

METHODS

A prospective observational study was conducted on 123 adults undergoing digital FURS for renal stones at Bach Mai Hospital (May 2023-July 2025). Preoperative CT was used to assess stone burden and lower pole anatomy. SFR was defined functionally as the absence of residual fragments >4 mm on ultrasound assessment. Univariate and multivariate logistic regression analyses were performed.

RESULTS

Perioperative and 1-month postoperative SFR were both 75.6%. Multivariate analysis identified two independent associations with stone-free rate, including stone area ≤110 mm² (immediate OR = 5.61; 95% CI: 1.85-17.00; one-month OR = 6.20; 95% CI: 1.30-29.67) and absence of lower pole stones (perioperative OR = 3.65; one-month postoperative OR = 13.16).

CONCLUSION

Digital FURS demonstrates high efficacy and safety in renal stone management, with stone burden and lower pole anatomy emerging as the most important determinants of treatment outcomes.