Risk of bleeding after retrograde intrarenal surgery vs miniaturised percutaneous nephrolithotomy for 10–20 mm renal stones: a not so different safety profile

Objective To assess differences in bleeding risk between retrograde intrarenal surgery (RIRS) and minimally invasive miniaturised percutaneous nephrolithotomy (mini‐PCNL) for 10–20 mm renal stones. Patients and methods A total of 176 patients with a renal stone between 10 and 20 mm were treated. For all patients the Stone Management According to Size‐Hardness (SMASH) score was calculated: Hounsfield units × stone maximum size (cm)/100. Patients with score of <15 underwent RIRS (90 patients, Group A), whereas patients with score ≥15 underwent mini‐PCNL (86 patients, Group B). In both groups the Cyber Ho laser was used. A statistical analysis was carried out to assess differences in the risk of bleeding. Results Preoperative features were comparable. The mean maximum stone diameter was 17.1 and 16.8 mm in Groups A and B, respectively ( P = 0.13). The stone‐free rate was comparable (87.8% vs 95.3%, P = 0.07). The overall complication rate was 14.4% and 18.6% in Groups A and B, respectively ( P = 0.09). Gross haematuria was observed in five cases (5.5%) after RIRS and seven (8.1%) after mini‐PCNL ( P = 0.07). The mean haemoglobin drop was 12 and 2 g/L at the first and third postoperative day after RIRS vs 17 and 3 g/L after mini‐PCNL ( P = 0.06 and P = 0.21, respectively). Blood transfusions and renal embolisation were never necessary. Conclusion When managing renal stones between 10 and 20 mm taking into account both size and hardness with the application of the SMASH score, RIRS and mini‐PCNL show comparable efficacy. A higher bleeding risk has been expected with percutaneous approaches; however, in our cohort the incidence of clinically significant bleeding was low and comparable between the two groups when adopting mini‐PCNL.