Clinical Research Directory

Inclusion criteria: * Patients aged 18-65 years of either gender presenting with renal and/or upper ureteric calculi ≤20 mm requiring flexible ureteroscopy (FURS). * Patients in whom primary ureteral access has failed because of a tight or tortuous ureter. * Patients in whom a DJ ureteral stent has been placed following failed primary ureteral access. * Patients willing to undergo repeat FURS after two or four weeks of preoperative ureteral stenting. * Patients who provide written informed consent to participate in the study. Exclusion criteria: * Patients with lower ureteric stones or renal/upper ureteric stones \>20 mm. * Patients with active urinary tract infection, defined as urine culture showing ≥10⁵ CFU/mL of a pathogenic organism or body temperature ≥38°C at the time of repeat FURS. * Patients with uncorrected coagulopathy, defined as INR \>1.5, platelet count \<50,000/µL, or aPTT \>1.5 times the laboratory upper limit of normal. * Patients with significant renal impairment, defined as estimated glomerular filtration rate (eGFR) \<30 mL/min/1.73 m². * Patients with a history of major ureteric surgery or ureteral reconstruction on the affected side. * Patients requiring emergency intervention because of obstructed infected urinary tract, defined by fever ≥38°C with radiological evidence of urinary obstruction.