Recommended antibiotic prophylaxis regimen in retrograde intrarenal surgery: evidence from a randomised controlled trial

Objective: To study the incidence of postoperative systemic inflammatory response syndrome (SIRS) following different antibiotic prophylaxis (ABP) regimens in retrograde intrarenal surgery (RIRS). Patients and Methods: Single-centre, randomised, controlled trial (August 2014–September 2017) including 426 patients with renal stones with preoperative sterile urine managed by RIRS (ClinicalTrials.gov NCT02304822). Different ciprofloxacin-based ABP regimens were used and included a zero dose, single dose (30 min before surgery) or two doses (first dose at 30 min before RIRS and additional dose within 6 h after RIRS). The incidence of SIRS was compared using intention-to-treat (ITT) and per-protocol (PP) analyses. Results: Each group enrolled 142 patients. In the ITT analysis, a zero dose of ABP was statistically similar to the two ABP regimes for the incidence of SIRS (9.9% vs single dose 4.9%, P = 0.112; vs two doses 4.2%, P = 0.062). There were also no relevant differences across groups in the PP analysis; no urosepsis was recorded. In subgroup analysis with stratification by stone area, the three regimens all had a low and similar incidence of SIRS for stones of ≤200 mm2 in the ITT analysis with a sufficient power value (5.4% vs 6.2% vs 3.6%, P = 0.945 vs single dose and P = 0.553 vs two doses). However, there was a greater chance of SIRS in patients who received no ABP with stones of >200 mm2 (18% vs single dose 4.3%, P = 0.036; vs two doses 5.5%, P = 0.044). Similar trends were seen in the PP analysis. Conclusions: For patients with preoperative sterile urine, ABP is not strongly recommended in patients with stones of ≤200 mm2, but for stones >200 mm2 single-dose ABP is still required.