Percutaneous nephrostomy (PCN) is usually a straightforward procedure, with a target success rate of 98% for dilated collecting systems and a major complication rate of 1%-4%. Optimizing patient preparation and imaging, and the use of appropriate equipment, increases technical success and minimizes complications.

The main indications for PCN are ureteric obstruction with or without infection and stone disease. A urologic and/or oncologic evaluation of the patient should be performed before PCN since alternatives as ureteric stent or no treatment might be considered in some cases.

In easy cases (significant hydronophrosis, good imaging on US, and a puncture route less than 6 cm) I prefer to perform PCN with a direct puncture (single step technique) with the 7 Fr trocart pigtail catheter. A needle guide mounted on the transducer is helpful; however, more skilled US interventionalists might prefer the free-hand technique. For internal fixation a string-lock mechanism is used, the external fixation is established with a dedicated drainfix plaster.

In difficult cases including cases without hydronephrosis, a two step technique (Seldinger) is used. The calyx is punctured with an 18 gauge needle; a stiff guidewire (with soft tip) is inserted and finally, the catheter is introduced over the guidewire. The procedure can be monitored with fluoroscopy including x-ray contrast; however, the use of dilute US contrast has replaced x-ray in almost all our PCN procedures. In complicated cases (no hydronoprrosis), a puncture needle of fine-needle size may reduce the risk for bleeding, however, this technique requires initially a thin guidewire followed by dilatation and replacement with the stiff guidrwire.