One Session or Two? A Meta-Analysis of Same-Session Versus Staged Bilateral Percutaneous Nephrolithotomy

Same-session bilateral kidney stone surgery cut hospital stays by nearly 3 days with no difference in stone clearance or complication rates across 749 patients

Journal: Journal of Endourology | Published: 2026-01-09 | Type: Meta-Analysis, Systematic Review | PMID: 41810589 Authors: Machado Filho C et al. (Pontifical Catholic University of Paraná, University of São Paulo, and institutions across Brazil and Canada) Funding/COI: Funding not disclosed; authors declare no conflicts of interest

Summary

Bilateral kidney stones are typically treated in two separate percutaneous nephrolithotomy (PCNL) sessions — staged bilateral PCNL (sPCNL) — with the staged approach favored historically for safety. This meta-analysis of five comparative studies pooling 749 patients found that performing both sides in a single operative session (ssPCNL) achieves equivalent stone-free rates and complication profiles while cutting hospital stay by nearly three days. The caveat is substantial: only five studies qualified, heterogeneity on the headline hospital-stay result is high, and every included study came from specialized high-volume centers.

Claims

• No statistically significant difference in stone-free rate between ssPCNL and sPCNL (OR: 0.80; 95% CI: 0.47–1.36)
• No significant difference in minor complications (Clavien-Dindo grade I–II; OR: 0.88; 95% CI: 0.44–1.73)
• ssPCNL associated with significantly shorter hospital stay (MD: −2.92 days; 95% CI: −3.60 to −2.24; I² = 84.7%)
• Reduced operative time with ssPCNL after sensitivity analysis (MD: −45.18 minutes) — not significant in primary analysis
• Transfusion requirements comparable between groups

Study Quality

This is a PRISMA-compliant systematic review using a random-effects model — the correct choice given cross-study heterogeneity — with risk of bias assessed via RoB 2 for randomized trials and ROBINS-I for nonrandomized studies. That's methodologically sound.

The problem is the evidence base underneath it: five studies and 749 patients. The I² of 84.7% on hospital stay is high enough to question whether pooling those numbers means anything coherent across different centers, patient selection practices, and discharge protocols. The operative time benefit required sensitivity analysis to reach significance and was not robust in the primary analysis. Confidence intervals on both stone-free rate and complications are wide enough to include clinically meaningful harm in either direction. The conclusions are technically defensible given the data, but the data aren't yet strong enough to generalize confidently.

Red Flags

• Only five studies met inclusion — the entire conclusion rests on a thin evidence base
• High heterogeneity for hospital stay (I² = 84.7%) undermines the primary efficiency finding
• Operative time reduction only emerged after sensitivity analysis; not a primary result
• "Appropriately selected patients in experienced centers" in the conclusion is doing enormous work — no standardized selection criteria across studies
• All included studies appear to be from specialized, high-volume centers; generalizability to lower-volume hospitals is unknown
• Funding source not disclosed

Strengths

• PRISMA-compliant with appropriate dual risk-of-bias assessment (RoB 2 + ROBINS-I)
• Random-effects model correctly applied
• Both primary and secondary outcomes analyzed systematically
• Publication bias assessed
• Multi-country author group adds some geographic breadth

Verdict

This meta-analysis is competently executed on a literature too sparse to support confident conclusions. Five studies is not a mandate to restructure bilateral PCNL practice. The hospital stay reduction is real and clinically meaningful if it holds — nearly three fewer days per patient is significant at a system level — but the I² of 84.7% means that number may not travel well outside the specific centers studied. Read this as a reasonable justification for prospective trials, not as evidence that same-session PCNL is ready for widespread adoption at centers without dedicated PCNL programs.