A total of 134 percutaneous treatments were performed for renal stones <2cm in diameter. Among the treatments, 40 were minipercs, 67 were standard PNLs, and 27 were tubeless PNLs.

Miniperc operative time was longer than that of standard PNL (155.5 vs 106.6min, respectively) and tubeless PNL (95.9min). Conversely, there was an advantage for miniperc over standard PNL in terms of a significantly reduced hematocrit drop (4.49% vs 6.31%). No miniperc patients required blood transfusions, whereas two did in the standard PNL group and one in the tubeless PNL group. There was no statistical difference in terms of the amount of analgesics between the standard PNL and miniperc groups, although this difference was statistically significant between the miniperc and tubeless PNL groups (73.8 vs 41.1mg, respectively). Hospitalization for the miniperc group was shorter than that required by the standard PNL group (3.05 vs 5.07 days), but tubeless PNL offered the best result (2.18 days). The stone-free rate was 100% in the tubeless PNL group, 94% in the standard PNL group, and 77.5% in the miniperc group.

Our retrospective study failed to demonstrate significant advantages of the miniperc technique. As such, we no longer perform miniperc but instead use tubeless PNL when possible.

Guido Giusti, Alessandro Piccinelli, Gianluigi Taverna, Alessio Benetti, Luisa Pasini, Matteo Corinti, Alessandro Teppa, Silvia Zandegiacomo de Zorzi, Pierpaolo Graziotti

Department of Urology, Istituto Clinico Humanitas, IRCCS, via Manzoni 56, 20089 Rozzano, Milan, Italy

Accepted 25 July 2006 published online 14 August 2006.