US-guided nephrostomy with the aid of a magnetic field-based navigation device in the porcine pelvicaliceal system

PURPOSE: To assess the technique and feasibility of ultrasound (US)-guided nephrostomy performed with the aid of a magnetic field-based navigation dev ice. MATERIALS AND METHODS: Twelve percutaneous nephrostomy procedures were perf ormed in seven domestic pigs under real-time US guidance employing a naviga tion system. Two magnetic field sensors registered the actual position of t he puncture needle and the US transducer. The actual needle position and th e aimed puncture tract were graphically projected into the real-time US ima ges, allowing exact navigation of the needle. After placement of the needle into the renal pelvis, the nephrostomy tube was inserted by means of the S eldinger technique. RESULTS: The puncture procedure was successfully performed in each case. Th e renal pelvis was punctured in a single attempt in 10 of 12 cases. In two cases, multiple attempts were necessary because bending of the puncture nee dle led to inaccuracies of the navigation system. With exception of two sma ll perirenal urinomas, no complications were seen. CONCLUSIONS: The magnetic field-based navigation device allows easy and acc urate performance of nephrostomy guided solely by US.