Vacuum-Assisted Mini-PCNL is Associated with Lower Postoperative SIRS: A Real-World Cohort Study

Background: Postoperative systemic inflammatory response syndrome (SIRS) remains a key complication after mini-percutaneous nephrolithotomy (mini-PCNL) and is often related to elevated intrarenal pressure and bacterial translocation. Vacuum-assisted mini-PCNL (VmPCNL) has been developed to mitigate this risk through active pressure control. Objective: To evaluate the association between VmPCNL and postoperative SIRS and to identify the independent predictors of SIRS in a real-world cohort. Materials and Methods: A retrospective cohort study was conducted of patients undergoing mini-PCNL at a tertiary referral center between January 2021 and May 2025. Patients were stratified into standard mini-PCNL (SmPCNL) and VmPCNL groups. The primary endpoint was SIRS within 48 hours post-surgery. Secondary outcomes included operative time, stone-free rate (SFR), and length of hospital stay (LOS). Multivariable logistic regression was used to identify independent predictors of SIRS. Results: A total of 136 patients were included in the study (SmPCNL, n = 78; VmPCNL, n = 58). The incidence of postoperative SIRS was significantly lower in the VmPCNL group (8.6% vs 21.8%, p = 0.036). VmPCNL was also associated with shorter operative time (median 90 minutes vs 115 minutes, p = 0.038) and reduced LOS (p = 0.012). Stone-free rates were comparable between the groups, indicating no compromise in procedural efficacy. In the multivariable analysis, VmPCNL was independently associated with a lower risk of SIRS (adjusted OR [aOR] 0.44, 95% CI 0.19– 0.98, p = 0.041), while a positive preoperative urine culture was an independent risk factor (aOR 2.60, 95% CI 1.01– 6.60, p = 0.045). Conclusion: In this real-world cohort, VmPCNL was associated with a lower SIRS incidence and improved perioperative efficiency without compromising stone-free outcomes. The mechanism may involve improved intraoperative outflow dynamics through active suction, although direct measurement of intrarenal pressure is needed to confirm this hypothesis.