This prospective, randomized, comparative study aims to evaluate the impact of aspirating and non-aspirating ureteral access sheaths on success rates and complications in patients undergoing retrograde intrarenal surgery (RIRS) for kidney stones. A total of 70 patients with renal stones smaller than 2 cm will be enrolled and randomly assigned to two groups. One group will undergo RIRS using a non-aspirating ureteral access sheath, while the other group will be treated using an aspirating ureteral access sheath.

The primary outcome of the study is the stone-free rate, which will be assessed at postoperative follow-up. Secondary outcomes include operative time, fluoroscopy time, length of hospital stay, postoperative complications according to the Clavien-Dindo classification, infection-related parameters, and the need for ureteral stenting.

The study aims to determine whether the use of an aspirating access sheath improves surgical outcomes by reducing intrarenal pressure, enhancing visualization, and decreasing complication rates. The findings are expected to contribute to optimizing device selection and improving clinical outcomes in endoscopic kidney stone surgery.

This study is designed as a prospective, randomized, comparative clinical trial to evaluate the effectiveness and safety of aspirating versus non-aspirating ureteral access sheaths in patients undergoing retrograde intrarenal surgery (RIRS) for kidney stones.

Ureteral access sheaths are commonly used during RIRS to facilitate repeated access to the collecting system, maintain low intrarenal pressure, and improve visualization. While conventional non-aspirating sheaths allow passive outflow of irrigation fluid, aspirating sheaths provide active suction, which may enhance fragment evacuation, reduce intrarenal pressure, and potentially decrease infectious complications. However, comparative clinical data between these two approaches remain limited.

In this study, a total of 70 patients aged 18 to 75 years with renal stones smaller than 2 cm will be enrolled after providing informed consent. Patients will be randomized into two groups using a computer-generated block randomization method. The first group will undergo RIRS using a non-aspirating ureteral access sheath, while the second group will undergo RIRS using an aspirating ureteral access sheath. All procedures will be performed using a standardized surgical technique.

Demographic characteristics, stone-related parameters, and perioperative variables will be recorded. Postoperative follow-up will include clinical and radiological evaluation. Stone-free status will be assessed during postoperative follow-up. Complications will be classified according to the Clavien-Dindo classification. Additional parameters, including operative time, fluoroscopy time, length of hospital stay, infection-related laboratory findings, and the need for auxiliary procedures, will also be evaluated.

The aim of this study is to determine whether the use of an aspirating ureteral access sheath improves surgical efficiency and safety compared with a conventional sheath. The results are expected to provide evidence to guide clinical decision-making in endoscopic kidney stone surgery.

Inclusion Criteria:

• Patients aged between 18 and 75 years
• Patients diagnosed with kidney stones smaller than 2 cm
• Patients scheduled for retrograde intrarenal surgery (RIRS)
• Patients who provide written informed consent

Exclusion Criteria:

• Patients with active urinary tract infection
• Patients with coagulopathy
• Pregnant patients
• Patients unable to tolerate the lithotomy position
• Patients with incomplete clinical or laboratory data

Individual participant data will not be shared due to privacy concerns and institutional data protection policies. All data collected in this study will be used solely for research purposes and will remain confidential.