Safety and outcomes of second-look percutaneous nephrolithotomy for complex renal stones: a retrospective study

Residual stones after percutaneous nephrolithotomy (PCNL) remain a major clinical challenge, particularly in patients with large or complex calculi. Second-look PCNL offers a minimally invasive option for achieving complete stone clearance; however, realworld data on outcomes, timing, and predictive factors are limited.

We retrospectively analyzed 72 patients who underwent second-look mini-PCNL at a high-volume tertiary center. Perioperative parameters were compared between procedures and between stone-free and residual stone groups. Stone-free status was defined as the absence of residual fragments ≥ 4 mm on non-contrast computed tomography. Outcomes of early (same admission) versus delayed second-look PCNL were evaluated.

Most patients had high stone complexity, with 79.17% classified as Guy's Stone Score grade 4. The overall stone-free rate after second-look PCNL was 55.56%. Multivariate analysis identified the presence of more than five stones as the only independent predictor of residual fragments (OR 6.49, 95% CI 1.65- 25.52; p = 0.007). Operative time and complication rates were comparable between procedures, while early re-intervention significantly reduced hospitalization duration and antibiotic use (both p < 0.01).

Despite a modest SFR, second-look PCNL is a safe and effective strategy for managing residual stones. Early reintervention during the same admission improves recovery and optimizes resource utilization.