Influence of sheath size on suction mini-PCNL outcomes: An observational study from the EAU endourology section and the global suction in mini-PCNL collaborative study group.

OBJECTIVE

We aim to evaluate the association between sheath size and outcomes in suction mini-percutaneous nephrolithotomy (SM-PCNL).

MATERIALS AND

METHODS

A prospective, multicentre study enrolled 1534 patients undergoing SM-PCNL from March to November 2024 across 30 centres. Patients were stratified into three groups: Group 1 (14-15 Fr, n = 780), Group 2 (16-18 Fr, n = 388), and Group 3 (20-22 Fr, n = 366). Primary outcome was 30-day stone-free rate (SFR) determined by non-contrast CT. Secondary outcomes included complications, operative times and hospital stay.

RESULTS

Group 3 achieved the highest zero residual fragment rate (92.6%) compared to Groups 2 (80.7%) and 1 (79.5%) (p < 0.001). Operative times were shortest in Group 3 (36 min) and longest in Group 2 (65 min). Larger sheaths were associated with significantly higher overall complication rates: Group 1 (7.6%), Group 2 (14.4%) and Group 3 (14.8%) (p < 0.001). Transfusion requirements increased with sheath size: 0% (Group 1), 1.5% (Group 2) and 3.3% (Group 3). Group 3 had exclusive pleural injuries requiring chest tubes (2.7%) and highest pelvicalyceal perforation rates (4.1% vs 1.3% in Group 2, 0% in Group 1). Larger sheath (16/18 Fr: OR 1.82; 21/22 Fr: OR 4.14) and single step dilation (OR 3.84) were associated with higher odds of zero residual fragments. Sheath size 21/22 Fr (OR 2.12) and increasing Guys stone score (score 2: OR 1.94; score 3: OR 3.51; score 4: OR 2.63 95% CI) were factors significantly associated with higher odds of overall complications.

CONCLUSIONS

Sheath selection in SM-PCNL requires balancing efficacy against safety. Larger sheaths (20-22 Fr) optimize stone clearance but increase complications. Smaller sheaths (14-15 Fr) offer superior safety for simple cases. Intermediate sizes (16-18 Fr) may represent an optimal compromise for moderately complex stones.