Randomized comparison of 4.5/6 Fr versus 6/7.5 Fr ureteroscopes for laser lithotripsy of lower/middle ureteral calculi: towards optimization of efficacy and safety of semirigid ureteroscopy

Background and purpose To compare 4.5/6 Fr versus 6/7.5 Fr semirigid ureteroscopes in terms of safety and efficacy in adult non-obese patients with middle or lower ureteric stones. Materials and methods A total of 198 patients with middle/lower ureteric stone and a BMI ≤ 30 kg/m 2 were recruited. Patients were randomized according to the size of ureteroscope into two groups: group 1 where a 4.5/6 Fr semi-rigid ureteroscope was used, and group 2 where a 6/7.5 Fr semi-rigid ureteroscope was used. Patient’s demographic, stone characteristics, intraoperative and postoperative outcomes including stone-free rate (SFR) and complications were compared. Results Preoperative characteristics in terms of age, sex, BMI, and stone location, side, size, and HU were comparable between both groups ( p values > 0.05). The overall SFR was significantly higher in group 1 (0.004). Balloon dilatation was not required in all patients of group-1 compared with 33% of group-2 ( p = 0.0001). The JJ stent was required in 10% of group-1 compared with 30% of group-2 ( p = 0.0004). Failure to reach the stone due to tight ureter occurred in 8% of group 2 ( p = 0.003), respectively. Traxer’s grade 1 ureteral injury occurred in 2% of group-1 versus 14% of group-2 ( p = 0.001). Consequently, hematuria was significantly lower in group-1 (1% vs. 8%; p = 0.01), respectively. The hospital stay < 9 h was significantly higher in group 1 ( p = 0.0001). Conclusions The 4.5/6 Fr semi-rigid Ureteroscope was associated with significantly higher SFR and shorter hospital stay, with lower ureteral injury, fewer double-J stenting, and without the need for intraoperative balloon dilatation for the ureter.