Accuracy of Ultrasound for Detecting Residual Fragments During RIRS

Ultrasound is currently gaining popularity as an alternative imaging modality for the diagnosis and treatment of urolithiasis. However, the benefit of ultrasound on the diagnostic accuracy of detecting residual fragments during retrograde intrarenal surgery (RIRS) has never been evaluated in a randomized study. Its use would reduce radiation exposure for patients and care team members as well as improve stone free clearance rates for surgery. Therefore, The investigators plan to conduct a randomized trial to assess the diagnostic accuracy of ultrasound and fluoroscopy in conjunction with endoscopic examination for detecting residual stone fragments during retrograde intrarenal surgery. After admission, approximately 172 subjects will be randomized in a 1:1 ratio to receive ultrasound or fluoroscopy before completing RIRS. Subsequently, four weeks after the operation, the investigators will compare with routine low-dose non-contrast computed tomography as a gold standard for detecting residual fragments. If ultrasound is more accurate than fluoroscopy in detecting residual fragments, the investigators will encourage this approach as it can reduce radiation exposure for patients and healthcare professionals.