Impact of Forced Diuresis on the Residual Fragment Rate After Flexible Ureteroscopy for Management of Renal Stones

This randomized controlled clinical trial evaluated whether furosemide-assisted forced diuresis during flexible ureteroscopy reduced the residual fragment rate and improved stone clearance in patients with renal stones measuring up to 30 millimeters. Adult patients undergoing flexible ureteroscopy were randomized into two parallel groups: an experimental group that received intravenous furosemide during the procedure and a control group that received standard perioperative and postoperative care without furosemide. Residual stone fragments were assessed using low-dose non-contrast computed tomography on postoperative day 1 and at 6 weeks after the procedure. The primary outcome was the proportion of patients with residual stone fragments greater than 2 millimeters on postoperative day 1. Secondary outcomes included the proportion of patients with residual stone fragments greater than 2 millimeters at 6 weeks, operative time, postoperative complications, and the need for auxiliary treatment for clinically significant residual stones.

Inclusion Criteria: * Adult patients aged 18 years or older. * Patients who underwent flexible ureteroscopy for renal stones measuring 30 millimeters or less. Exclusion Criteria: * Patients with active urinary tract infection. * Patients with a history of previous open renal surgery or renal trauma. * Patients with contraindications to anesthesia, such as severe cardiac disease, uncontrolled diabetes mellitus, or severe coagulation disorder. * Patients with severe renal impairment, defined as an estimated glomerular filtration rate less than 30 milliliters per minute per 1.73 square meters. * Known Ureteric stricture and pelvi-ureteric junction obstruction * Patients with a single kidney. * Patients with contraindications to furosemide administration. * Patients with congenital renal anomalies.