STONE DISEASE

Miniperc? No, Thank You!
Giusti G, Piccinelli A, Taverna G, Benetti A, Pasini L, Corinti M, Teppa A, Zandegiacomo de Zorzi S, Graziotti P
Department of Urology, Istituto Clinico Humanitas, IRCCS, Milan, Italy
Eur Urol. 2007; 51: 810-5

• Objectives: The aim of this retrospective study was to evaluate the results of our miniperc series through comparison with results from standard percutaneous nephrolithotomy (PNL) and tubeless PNL series in the treatment of stones < 2cm in diameter.
• Patients and Methods: 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.
• Results: Miniperc operative time was longer than that of standard PNL (155.5 vs 106.6 min, 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 41.1 mg, 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.
• Conclusions: 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.
  
  
• Editorial Comment
  As an early proponent of a mini-PCNL, the main advantage I anticipated with a mini-PCNL was a decrease in blood loss. Indeed, this hypothesis is supported by the current study. As it stands, decrease in blood loss would be an outcome worth striving for, yet not at the expense of lower stone-free rates. Improvements in instrumentation, in particular smaller ultrasonic devices, are needed to help raise the success rate of mini-PCNL to the expected standard. The issue of pain post-PCNL will be decided more by the size of tube than the size of tract - many studies now support the use of a small-bore or tubeless approach to minimize this aspect of PCNL-associated morbidity. As such, one might rephrase the title from “No, Thank You” to “Not Yet”. If the future brings improvement in instrumentation, one might anticipate that a tubeless mini-PCNL may resurface.

Dr. Manoj Monga
Professor, Department of Urology
University of Minnesota
Edina, Minnesota, USA