Mini‐percutaneous nephrolithotomy vs flexible ureteroscopy for 1–2 cm lower pole renal stones: a randomised controlled trial

Objective To compare the safety and efficacy of flexible ureteroscopy (f‐URS) and ambulatory tubeless mini‐percutaneous nephrolithotomy (mini‐PCNL) in the treatment of 1–2 cm lower calyceal renal stones. Patients and Methods Patients who underwent f‐URS and mini‐PCNL for the treatment of 1–2 cm lower calyceal renal stones between October 2020 and November 2023 were evaluated in a randomised controlled trial. A total of 72 patients were included in the study. All patients underwent a computed tomography renal colic scan preoperatively, on postoperative Day 1 (POD 1), and at 3 months follow‐up. We compared perioperative outcomes, including operative time and hospital stay. Additionally, we evaluated follow‐up outcomes, such as the stone‐free rate (SFR) and complications. All patients were discharged home on the same operative day. Results There were no significant differences in preoperative baseline data between the two surgical groups. A significantly longer median operative time was reported in the mini‐PCNL group ( P = 0.04). The median hospital stay was 5 h and 4 h in the mini‐PCNL and f‐URS groups, respectively ( P = 0.14). On POD 1, the SFR, defined as the absence of residual fragments measuring 0 cm, was 50% for mini‐PCNL vs 11.1% for f‐URS ( P < 0.001). When a total cut‐off of <0.4 cm was utilised, the SFR was 75% in the mini‐PCNL group vs 22.2% in the f‐URS cohort ( P < 0.001). At 3 months follow‐up, the SFR remained favourable for mini‐PCNL at 72.2% vs 37.1% for f‐URS ( P = 0.003), with a cut‐off of 0 cm, and it increased to 86.1% for mini‐PCNL vs 65.7% for f‐URS ( P = 0.04) when a total cut‐off of <0.4 cm was applied. There was no significant difference in postoperative complications between the two groups. Two patients (5.7%) in the f‐URS group required re‐treatment. [Correction added on 5 November 2024, after first online publication: Within the Results section, ‘<4 cm’ has been corrected to ‘<0.4 cm’.] Conclusions Ambulatory tubeless mini‐PCNL and f‐URS are effective treatment options for 1–2 cm lower calyceal renal stones. Both techniques have a comparable hospital stay and complication rates, with a significantly better SFR with mini‐PCNL.