Abstract: Objective To investigate the efficacy of flexible negative pressure suction sheath combined with ureteroscope in the treatment of 1-3 cm renal stones and the risk factors for postoperative infection. Methods The study enrolled 100 patients with 1-3 cm renal stones in our hospital from January to December 2025. All patients were treated by flexible negative pressure suction sheath combined with ureteroscope lithotripsy. General patient information, stone characteristics, operation time, primary stone clearance rate, hospital stay, and complications were recorded. Patients were divided into an infection group and a non-infection group based on whether postoperative infection complications occurred. Univariate and multiple logistic regression analyses were used to analyze the risk factors for postoperative infection. Results All 100 patients successfully completed the surgery without conversion to open surgery or percutaneous surgery. The primary stone clearance rate was 92.0% （92/100）, with a stone-free rate of 78.0% and residual stones ≤ 4 mm accounting for 14.0%. The average operation time was （62.4±15.8） min, and the average hospital stay was （4.6±1.3） d. The postoperative complication incidence rate was 13.0% （13/100）, mainly Clavien-Dindo grade I-II. Seven cases （7.0%） developed infection-related complications after surgery, mainly presenting as fever or urinary tract infection. All patients improved after aggressive anti-infection and symptomatic treatment, with no severe sepsis or deaths. Multiple logistic regression analysis indicated that preoperative positive urine culture, prolonged operation time, and large stone burden were independent risk factors for postoperative infection （P<0.05）. Conclusion Flexible negative pressure suction sheath combined with ureteroscope is effective in the treatment of patients with 1-3 cm renal stones, with a high stone clearance rate and few complications. The occurrence of postoperative infection in patients is related to factors such as preoperative urinary tract infection status, stone burden, and operation duration. Preoperative assessment, infection control, and optimization of surgical procedures can further reduce the risk of postoperative infection in the patients, and are worthy of clinical promotion and application.

Key words: Flexible negative pressure suction sheath, Flexible ureteroscope, Kidney stones, Postoperative infection, Risk factors