To compared the safety and effectiveness of negative suction retrograde intrarenal surgery(nsRIRS) for upper urinary stones, including patients with initial negative urine culture, and summarized the treatment experience of patients with positive urine culture.

Based on preoperative initial urine culture results, from January 2023 to April 2024, all patients undergoing nsRIRS were divided into the positive group(pRIRS,n=37) and negative group(nRIRS,n=378). Propensity score matching ( PSM ) analysis was performed using a multivariate logistic regression model based on age, gender, body mass index, history of stone treatment, comorbidities (hypertension/diabetes), stone side, stone diameter, CT value, hydronephrosis, stone location, ASA score, renal malformation, dilated ureter, pre-JJ stent. After PSM, the Paired Student’s t-test and the McNemar test were used to analyze the differences between the two groups of variables.

Before PSM, statistical differences were observed in gender, stone size, dilated ureter, and Pre-JJ stent. After PSM, 31 pairs were matched, and no statistical differences were found in all pre-surgical variables. After matching, the operation time in the pairs group was longer than that in the nRIRS group (61.84 ± 16.80 vs 52.16 ± 14.25, P = 0.01). Similarly, the pRIRS group had a greater hemoglobin decline than the nRIRS group, 8.94 ± 1.93 vs 7.68 ± 2.82 (P=0.04). No statistical differences were observed in SIRS, ureteral injury, stone free rate, postoperative hospital stays. Additionally, no sepsis or fatalities occurred in either group.

Preoperation positive urine cultures did not increase the infection rate compared to patients with negative cultures when nsRIRS was used for upper urine stones. However, operation time and hemoglobin loss were increased.