The efficacy of flexible ureteroscopy for large volume stones and hazards of ureteral access sheath usage: A prospective randomized study.

Objectives: We aimed to assess the stone free rate of flexible ureteroscopy and laser lithotripsy (FURL) in upper urinary tract stones (UUTS) >20 mm and the risk of complications from ureteral access sheath (UAS) usage.

Methods: This is a prospective randomized clinical trial that included patients with UUTS larger than 20 mm who underwent FURL after randomization into two groups: group A (UAS) and group B (non-UAS). Data were collected for patients' demographics, stone parameters, operative and postoperative complications, and the outcome of FURL regarding stone-free rate (SFR) and perioperative complications, with a 6-month follow-up. Stone clearance was defined as the absence of fragments or the presence of fragments smaller than 2 mm on follow-up CT scans of the urinary tract (CTUT).

Results: One hundred and fifty-nine patients were evaluated. The mean stone size was 27.08 ± 6.185 mm. Complete stone-free status was achieved in 84.9% of the patients. No significant difference was detected between both groups regarding operative time or SFR. The ureteric injury was identified in 13 (8.1%) patients (10 in group A and 3 in group B, p: 0.0481). Five of them, from group A, revealed hydronephrosis after stent removal. Postoperative pain and fever were documented in 50 and 22 patients, respectively, without significant differences between both groups. Postoperative sepsis occurred in 7 patients (2 in group A, 5 in group B, p: 0.380) who required supportive care.

Conclusion: FURL without UAS is a safe and efficient treatment for upper urinary tract stones larger than 20 mm in the form of lower risk of ureteric injury.