Minimally invasive PCNL in patients with renal pelvic and calyceal stones.

Stones of the renal pelvis can be treated either by extracorporeal shock wave lithotripsy (SWL) or percutaneous nephrolithotomy (PCNL). As a low-risk procedure with a longer treatment period, SWL often leads to persistent residual stone fragments, whereas conventional PCNL achieves a higher stone-free rate and allows a shorter treatment period albeit with a somewhat higher surgical risk. To reduce the invasiveness of conventional PCNL, the application of a miniaturised instrument for PCNL (MPCNL) was evaluated. For MPCNL a rigid nephroscope with a calibre of 12 F was developed and used in 19 patients. After puncture of the kidney under ultrasound control and single-step dilatation, a 15 F Amplatz sheath was placed. Data on the stone size and location, stone-free rate, blood transfusions, operating time and complications were recorded. In all patients, the part of the kidney afflicted by the stone was successfully punctured. On average, retreatment rate was 0.7. The mean stone size was 2.4 cm(2). The average operating time was 99.2 min. In every case, the absence of residual stones was confirmed radiologically and nephroscopically. Hemorrhages requiring a blood transfusion did not occur. A febrile pyelonephritis occurred as a postoperative complication in one patient (= 5.3%). MPCNL represents an alternative to SWL for renal calculi with a size from 1 to 2 cm located in the renal pelvis and calices, especially the lower calix. The advantages are the short treatment time, the high stone-free rate and the accessibility of lower pole stones which are less amenable to SWL. MPCNL is not suitable for large concrements since the limited sheath diameter would increase the operating time. Due to this limitation, MPCNL represents an extension of the indication for conventional PCNL that it can in no way replace.