Reto Josef Bale MD, Abstract Co-Author: Nothing to Disclose

Peter Kovacs MD, Abstract Co-Author: Nothing to Disclose

Gerd Bodner MD, Abstract Co-Author: Nothing to Disclose

Thomas Lang, Abstract Co-Author: Nothing to Disclose

Martin Knoflach, Abstract Co-Author: Nothing to Disclose

Werner R. Jaschke MD, Presenter: Nothing to Disclose

Marion Haidu, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

The success of radiofrequency ablation depends on the distribution of the needle(s) in the tumor. Our purpose was to develop and evaluate a novel method for computer-assisted liver tumor puncture for radiofrequency ablation in 15 patients (27 lesions, 68 needles) using multipolar electrodes.

After oral intubation and immobilization of the patient in the BodyFix immobilization system (Medical Intelligence Inc., Schwabmünchen, Germany) a 3 mm contrast –enhanced helical CT scan was obtained in maximal exspiration. Depending on the size of the tumor (1,6-6 cm, mean size: 3,3 cm) 1-7 pathways for the placement of bipolar radiofrequency needles (Celon RF, Berlin, Germany) were planned on the Treon navigation system (Medtronic Inc., Boulder, USA). After sterile draping and registration using skin fiducials, the Atlas aiming device (Medical Intelligence, Schwabmünchen, Germany) was adjusted using the navigation system. In maximal exspiration the needles were advanced through the targeting device to the predefined depth. An intraoperative CT scan was sent to the navigation system and the accuracy of needle placement was evaluated by image fusion with the planning-CT. Follow-up CT scans were performed 2 weeks after the intervention and afterwards in a 3 month - interval.

Image-fusion revealed a needle displacement within 1-11 mms (mean error 6.2 mm). The mean duration from the planning CT to the verification CT was 35 minutes. In the follow-up contrast enhanced control-CTs (mean follow-up time: 8,2 months) no residual tumor was found in all patients except two. These patients were successfully retreated.

The novel method allows for precise puncture of liver lesions. Navigation and the use of bipolar needles seem to optimize the radiofrequency ablation technique especially in lesions bigger than 2,5 cm.

R.J.B.: Reto Bale, MD is co-developer of the BodyFix system and the targeting device and will receive financial returns in case the system is sold.

Bale, R, Kovacs, P, Bodner, G, Lang, T, Knoflach, M, Jaschke, W, Haidu, M, et al, , Navigated Placement of Multiple Multipolar Needles for Radiofrequency Ablation of Malignant Liver Lesions.  Radiological Society of North America 2005 Scientific Assembly and Annual Meeting, November 27 - December 2, 2005 ,Chicago IL. http://archive.rsna.org/2005/4418200.html