Objective: To report our prospective comparison of clinical efficacy between multimodular flexible ureteroscope, PolyScope, and conventional flexible ureteroscope, both combined with holmium laser lithotripsy in managing renal stones <3 cm in diameter.

Patients and methods: Between February 2011 and July 2014, a total of 360 adult patients with renal stones were randomized in a single tertiary-care center trial. For 180 patients in each arm, flexible ureteroscopy and holmium laser lithotripsy were done with either PolyScope or Olympus URF P-5 as control. The primary end points were single-session stone fragmentation rate and stone-free rate. The secondary end points comprised operation time, complication rate, and hospital stay.

Results: Demographic and preoperative parameters were comparable between 2 groups. For stones of different locations and sizes, single-session stone fragmentation rate of PolyScope was similar to that of URF P-5. However, for lower calyceal stones, URF P-5 was significantly better than PolyScope (82.0% vs 69.2%; P = .022). No statistically significant difference existed in single-session or overall stone-free rate, complication rate, and hospital stay. Mean operation time of PolyScope group was 92.6 ± 20.2 minutes, 9 minutes (10.8%) longer than that of URF P-5 group 83.3 ± 17.1 minutes (P < .01).

Conclusion: PolyScope demonstrates similar overall stone clearance rate to a conventional flexible ureteroscope in managing renal calculi <3 cm in diameter, but for lower pole stones, it is of inferior efficacy and it is more skillfully demanding, taking longer operation time.