Safety and efficacy of flexible and navigable suction combined with retrograde flexible ureteroscopy in the management of infectious stones

To compare the safety and efficacy of flexible and navigable suction (FANS) ureteral access sheath-assisted retrograde intrarenal surgery (FANS-RIRS) for infectious versus non-infectious stones. A retrospective study of 274 patients treated with FANS-RIRS (November 2023–December 2024). Patients were stratified postoperatively into groups based on stone composition. The infectious stone group (n = 61) comprised stones containing at least one of the following components: magnesium ammonium phosphate hexahydrate (struvite), carbonate apatite, or ammonium urate, either as pure or mixed compositions. The non-infectious stone group (n = 213) included other stone types such as metabolic stones, those associated with genetic abnormalities, and drug-induced stones. Outcomes included infectious complications (SIRS/sepsis), stone-free rate (SFR), operative time, and postoperative complications. Statistical analysis used t-tests, Mann-Whitney U, and chi-square tests. No sepsis occurred in either group. Immediate SFR was comparable (90.2% vs. 92.1%, p = 0.638), with residual stones in infectious cases primarily in lower-pole calyces or diverticula. Infectious stones showed higher preoperative urine culture positivity (32.8% vs. 20.6%, p = 0.046), but no differences in operative time, hospital stay, or complications. FANS-RIRS for infectious stones demonstrated comparable postoperative infection rates to non-infectious stones, proving safe and effective. However, postoperative antimicrobial stewardship and regular surveillance remained paramount for infectious stone management.