Intrarenal antimicrobial irrigation as an adjunct to systemic prophylaxis in upper tract endourology: a PRISMA-ScR scoping review of a limited and heterogeneous evidence base.

PURPOSE: This review maps evidence for adding antimicrobial or antiseptic agents to intrarenal irrigation during upper tract endourology and the physiological rationale linking intrarenal pressure to septic complications. METHODS: Following PRISMA-ScR guidelines, we searched PubMed and Scopus (see Methods for dates) for clinical outcomes of antimicrobial or antiseptic irrigation during retrograde intrarenal surgery (RIRS) or percutaneous nephrolithotomy (PCNL) in adults. Given anticipated heterogeneity, findings were synthesized narratively without meta-analysis. RESULTS: Four heterogeneous studies (1988-2024; N = 226) met inclusion criteria, spanning both RIRS and PCNL. Buck et al. (1988, n = 20) achieved sterile nephrostomy cultures using postoperative noxythiolin after PCNL (double-blind randomized controlled trial, RCT). Yildiz et al. (2024, n = 102) reported a borderline-significant fever/systemic inflammatory response syndrome (SIRS) reduction (composite outcome) with intraoperative gentamicin during RIRS (2.0% vs. 11.8%, p = 0.05). Kone et al. (2022, n = 48) and Rai et al. (2021, n = 56) used intraoperative povidone-iodine, alone or combined with gentamicin, against historical PCNL cohorts (fever 16.7% vs. 45.8%, p = 0.029; sepsis 3.5% vs. 8-10%, no p-value). No adverse events were reported, though ascertainment was not standardized and serum levels were not measured. CONCLUSION: In all four studies, adding intrarenal antimicrobial irrigation to standard systemic prophylaxis was associated with a lower rate of that study's own infectious or microbiological endpoint, with no reported harm. Differences in procedure, agent, timing, design and outcome preclude pooling, and none tested irrigation as a substitute for systemic prophylaxis. Findings are hypothesis-generating rather than practice-changing; adequately powered, concurrently controlled trials stratified by procedure and agent are needed before recommending adoption.