Standard v mini percutaneous nephrolithotomy in the supine modified lithotomy position: a randomized pilot study on...

Percutaneous nephrolithotomy (PCNL) is the recommended treatment for stones >2 cm in size. The majority of PCNL are still conducted with larger telescopes using tracts up to 30F in size. We have conducted a randomized pilot study comparing mini PCNL with our standard 22F PCNL for renal stones between 10 and 25 mm in diameter.

Patients were randomized to either PCNL (24F Amplatz sheath/22F nephrosocope) or mini PCNL (18F Amplatz sheath/11F nephroscope). All operations were performed in the modified supine position. Patients were reviewed with imaging to assess stone clearance and complications.

Eighteen well matched patients were randomized. All procedures were completed as planned and all were tubeless with no complications. There were no differences in operative time, analgesia requirements or length of stay. Seven of nine (77.75%) standard PCNL were completely stone free at CT review with a 2 mm and a 5 mm fragments in the other patients. Four (44.4%) of the mini PCNL group were stone free, with stone fragments 4-10 mm remaining in the others. 40 patients/arm would be required for an adequately powered study.

There was no advantage in using mini PCNL compared to our standard 24F PCNL in this pilot study. There may be benefits in using mini PCNL compared to the more widely used 30F PCNL and it may be a more cost-effective alternative to laser pyeloscopic stone procedures.