The acceptable criteria of stone burden and the significant factors to choose retrograde intrarenal stone surgery or miniaturized percutaneous nephrolithotomy for the treatment of renal stones > 10 mm: Beyond the Abstract

I became one of the core members for the Asian guideline panels for urolithiasis this year and I thoroughly reviewed the EAU and AUA guidelines again. The goal was to determine surgical plans for renal stones that were 'stone size' regardless of the presence of many stone-related parameters including stone location, density, number of stones, and surgeon’s treatment preference.

During my research, I could not determine any definitive evidence that suggests that cut-off levels should be 10, 15, or 20 mm. Some of the questions that were raised were what about 25? or 30? What about new technical developments achieved during the last decades? The basic principle should be that size criteria is not the only parameter to be considered. However, the stone size is still an important parameter to consider when deciding a surgical plan, so I analyzed just my surgical database to find the answers about the cut-off levels between retrograde intrarenal surgery (RIRS) and mini-PCNL (percutaneous nephrolithotomy), as well as between mini-PCNL and conventional PCNL.

The key findings from my results:

  1. RIRS shows the highest fragmentation efficiency at the 19.1 mm stone.
  2. It is best to choose mini-PCNL instead of RIRS when the stone size is bigger than 21.6mm and 15,000 mm3.
  3. It is best to choose large-bore PCNL instead of mini-PCNL when the stone size is bigger than 35mm and 43,000mm3."

The cut-off level of 20mm between RIRS and PCNL is it an acceptable cut-off level. 20mm is a quite good cut-off level for me as well because 20 is not so far from 19.1 or 21.6!! And it is more easy to memorize than 19.2 or 21.6!

Written by: Sung Yong Cho

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