This is a multicenter, randomized controlled trial comparing retrograde intrarenal surgery (RIRS) using a tip-flexible suction access sheath with standard percutaneous nephrolithotomy (PCNL) for the treatment of 2-3 cm unilateral renal stones. The aim is to evaluate the clinical efficacy and safety of the novel suction sheath-assisted RIRS compared to standard PCNL in terms of stone-free rate and postoperative complications. A total of 308 patients will be enrolled across four centers in China.

Kidney stones (renal calculi) are a common urological condition that can lead to pain, infection, and renal dysfunction. For renal stones measuring 2-3 cm, both retrograde intrarenal surgery (RIRS) and percutaneous nephrolithotomy (PCNL) are recognized treatment options. Traditional RIRS is less invasive but may be associated with lower stone-free rates for larger stones. A newly developed tip-flexible suction access sheath (TFS-UAS) allows improved access to renal calyces, reduces intrarenal pressure, and enables efficient stone fragment evacuation through continuous suction.

This study is a prospective, multicenter, randomized controlled trial designed to compare the effectiveness and safety of RIRS using the TFS-UAS versus standard PCNL in patients with unilateral renal stones measuring 2-3 cm. A total of 308 patients aged 18-80 years will be enrolled from four tertiary hospitals in China. Eligible participants will be randomized into two groups to receive either TFS-UAS-assisted RIRS or standard PCNL. The primary endpoint is the stone-free rate (SFR) at 3 months, assessed by CT scan. Secondary outcomes include postoperative infection rates, changes in hemoglobin and procalcitonin levels, hospital stay duration, and pain scores.

This study aims to provide high-quality evidence to guide surgical decision-making in the management of medium-sized kidney stones and to evaluate the potential advantages of the new suction-assisted sheath in minimally invasive endourology.

Inclusion Criteria:

1. Age between 18 and 80 years
2. American Society of Anesthesiologists (ASA) physical status classification of I-III
3. Single renal stone with a diameter between 2-3 cm confirmed by non-contrast CT scan
4. Signed written informed consent and willingness to comply with study procedures

Exclusion Criteria:

1. Anatomical abnormalities of the urinary tract (e.g., horseshoe kidney, ileal conduit)
2. Uncontrolled urinary tract infection
3. Absolute contraindications for RIRS or PCNL
4. Inability to understand or complete study documentation
5. Failure to follow study protocol or attend follow-up
6. Patients requiring urgent rescue or at high risk for irreversible harm during surgery
7. Patients who voluntarily withdraw from the study