Super-mini PCNL confers higher stone-free rate vs. RIRS

San Francisco-Super-mini percutaneous (SMP) nephrolithotomy may have some advantages over retrograde intrarenal surgery (RIRS) when treating 1- to 2-cm lower pole renal calculi, according to a comparative study.

At the 2018 AUA annual meeting in San Francisco, Chinese investigators reported that SMP appears to provide an overall significantly higher stone-free rate and lower auxiliary rate compared to RIRS in the treatment of 1- to 2-cm lower pole renal calculi.

The authors found no significant differences in surgical time and hospital stay between the two groups. However, the study demonstrated RIRS was advantageous in terms of hemoglobin drop rates and postoperative pain scores.

“We found that for the stones located in the lower pole that are 1 to 2 centimeters, both SMP and RIRS are safe and effective treatments. SMP will have a higher clearance,” said Yang Liu, MD, who is with the First Affiliated Hospital of Guangzhou Medical University, China.

Dr. Liu, who presented the findings at the meeting, said both percutaneous nephrolithotomy and RIRS are currently recommended for the treatment of 1- to 2-cm lower pole renal calculi. However, he said the optimal treatment option has not been thoroughly evaluated. He and his colleagues conducted a multinational, multicenter prospective randomized comparison of SMP and RIRS for the treatment of 1- to 2-cm lower pole renal calculi and examined the safety and efficacy of the two procedures (NCT02519634).

The authors enrolled 153 patients at nine Asian centers and one European center. All the participants were treated between August 2015 and March 2017. The primary outcomes were one-session stone-free rate and stone-free rate at 1-month postoperatively. For this investigation, the secondary outcomes analyses included blood loss, operating times, postoperative pain scores, auxiliary procedures, complications, and hospital stay.

Next: Stone-free rates comparedStone-free rates compared

The authors found that the stone-free rate was significantly higher in the SMP group compared to the RIRS group. The one-session stone-free rate was 94.8% in the SMP group and 75.0% in the RIRS group (p=.001). The overall stone-free rate was 97.4% 1-month postoperatively in the SMP group and 84.2% in the RIRS group (p=.005).

“We have been studying this technology for more than 5 years. This is the third generation of this technology,” Dr. Liu said in an interview with Urology Times. “We want to recommend this new technology to urologists because it would be highly efficient and safe.”

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The auxiliary rate was found to be lower in the SMP group (p=.001), but RIRS was found to be superior in terms of lower hemoglobin drop (p<.001). In addition, RIRS was found to result in better postoperative pain scores at 6 hours (p=.001), 24 hours (p=.004), and 48 hours (p=.043). The study also showed that the complication rates between the two groups were similar.

“We think this technology is something that will be very popular in the future. It is promising,” Dr. Liu said