Mini versus ultra-mini percutaneous nephrolithotomy in a paediatric population

To evaluate whether there would be a difference in outcome when the smaller ultra-mini 12 Fr sheath was used instead of the mini 16 Fr sheath for percutaneous nephrolithotomy (PCNL) in paediatric patients for stones less than 25 mm.

This was a prospective cohort study of patients who underwent PCNL in our hospital in a 2-year period from July 2016 to June 2018 by a single surgeon. PCNL was performed in a prone position and tract was dilated to the respective size using single step dilatation. Laser was used to fragment the stone. Stone-free outcome was defined as absence of stone fragment at 3 months on kidney, ureter, and bladder X-ray.

There were 40 patients in each group. Mean stone size was comparable between the two groups (14.5 mm vs. 15.0 mm). The procedure was completed faster in the 16 Fr group compared to 12 Fr group (24.5 min vs. 34.6 min). Stone clearance was highly successful in both groups (97.5% vs. 95.0%). There was no difference in complications between the two groups. The decrease in hemoglobin was minimal in both groups (0.2 g/dL vs. 0.3 g/dL).

We found that the success rates were similar in both mini PCNL and the smaller ultra-mini PCNL groups. No significant difference in bleeding was noted in our pilot study, however, operative time was longer in the ultra-mini group as compared to the mini sheath group.