The goal of this observational study is to learn about the effects of using negative pressure suction during retrograde intrarenal surgery (RIRS) in patients aged 18 and older with kidney stones. The main questions it aims to answer are:

1. Does using negative pressure suction during surgery affect the amount of irrigation fluid absorbed by the patient's body?
2. Does using negative pressure suction reduce the risk of postoperative infections, such as fever, systemic inflammatory response syndrome (SIRS), and urosepsis? Researchers will compare patients who undergo surgery with a negative pressure suction sheath to patients who undergo surgery with a standard sheath (without suction) to see if the suction technology reduces fluid absorption and lowers the risk of postoperative complications.

Participants will undergo their scheduled kidney stone surgery as part of their regular medical care. Researchers will collect their routine clinical data from the hospital system, including:

1. Preoperative test results (such as CT scans, ultrasounds, and urine tests).
2. Intraoperative data (such as surgery duration and the exact amount of fluid absorbed, measured by a monitoring device).
3. Postoperative recovery data (such as body temperature, pain levels, hospital stay length, and any signs of infection).

Inclusion Criteria:

• Patients aged 18 years and older with kidney stones who meet the surgical indications for RIRS;
• Patients who have provided informed consent.

Exclusion Criteria:

• Concurrent combination with other surgical procedures, such as percutaneous nephrolithotomy (PCNL);
• Patients with malignancies, urinary tuberculosis, immune system diseases, or hyperthyroidism;
• Congenital renal anomalies, such as polycystic kidney disease or horseshoe kidney;
• Presence of untreated urinary tract infections;
• Inability to tolerate surgery due to severe cardiopulmonary dysfunction, hepatic or renal insufficiency, or coagulation abnormalities.

Adult patients (typically aged 18 years and older) diagnosed with renal and/or upper ureteral stones who are scheduled to undergo retrograde intrarenal surgery (RIRS) at the urology department.

The clinical data involves sensitive patient privacy. We are currently undecided on sharing the IPD, as it requires specific informed consent from the patients and authorization from the hospital's ethics committee.