Introduction & Objectives
Percutaneous nephrolithotomy (PNL) or retrograde intrarenal surgery (RIRS) is recommended for the treatment of 1-2 cm lower pole (LP) renal calculi. However, the optimal treatment option remains controversial, and level 1 evidence comparing the two modalities is still deficient. A multinational multicenter prospective randomized comparison of super-mini percutaneous nephrolithotomy (SMP) and retrograde intrarenal surgery (RIRS) for the treatment of 1 to 2 cm LP renal calculi was done to evaluate the safety and efficacy of these procedures.
Material & Methods
153 patients with 1 to 2 cm LP renal calculi who underwent treatment between August 2015 and March 2017 were included in this study at 9 Asian centers and 1 European center. These patients were randomized to SMP and RIRS groups. One-session stone-free rate (SFR) and SFR at 1-month postoperatively were analyzed as the primary outcomes. The secondary outcomes analyses included blood loss, operative duration, postoperative pain scores, auxiliary procedures, complications and hospital stay. The study was registered at http://clinicaltrials.gov /(NCT02519634).
The SFR was significantly higher in the SMP group than in the RIRS group (one-session SFR 94.8% and 75.0%, P =0.001; overall SFR at 1-month postoperatively 97.4% and 84.2%, P =0.005). The auxiliary rate was lower in the SMP group (p =0.001). RIRS was found to be superior in terms of lower haemoglobin drop (P <0.001) and less postoperative pain scores at 6 h, 24 h and 48 h (P = 0.001, P = 0.004 and P = 0.043, respectively).There was no significant difference in the operating time and hospital stay. The overall complication rates were similar in the both groups.
SMP provides overall significantly higher SFR and lower auxiliary rate compared to RIRS in the treatment of 1-2 cm LP calculi, with no significant differences in surgical time and hospital stay. However RIRS was found to be advantageous regarding the haemoglobin drop rates and postoperative pain scores.