Multiple-electrode radiofrequency ablation: comparison with a conventional cluster electrode in an in vivo porcine kidney model.
OBJECTIVE
To compare multiple-electrode radiofrequency (RF) ablation versus RF ablation with a cluster electrode in an in vivo porcine kidney model.


METHODS
Thirteen female pigs (mean weight, 45 kg) were used for the study. In each animal, RF ablations were performed for 12 minutes with a conventional cluster electrode in one kidney (controls, n = 13) and a multiple-electrode configuration in the contralateral organ. Multiple-electrode ablations were performed with electrodes 1.5 cm apart (group 1, n = 7) or 2.0 cm apart (group 2, n = 6). The mean maximum temperature at the electrode tips was determined. After each animal was euthanized, the kidneys were removed and the ablation zones were sectioned into 5-mm transverse slices. A representative slice was stained with 2,3,5-triphenyl-2H-tetrazolium chloride. Standard ablation zone metrics were measured and differences between groups were analyzed for statistical significance.


RESULTS
The mean maximum ablation zone diameter was 3.0 cm +/- 0.6 (SD) for controls, compared with 5.0 cm +/- 0.5 for group 1 (P < .0001) and 4.4 cm +/- 1.0 for group 2 (P = .002). Mean ablation zone minimum diameter was higher for group 1 (P = .002) and group 2 (P = .03) than for controls. Isoperimetric ratios were lowest for group 2 (P = .04 vs controls) whereas the highest temperatures at the electrode tips were observed with group 1 (P = .02 vs controls).


CONCLUSIONS
In normal porcine kidney, multiple-electrode RF ablation produced larger zones of ablation than a cluster electrode. Efficacy was greater when electrodes were spaced 1.5 cm apart than when they were spaced 2.0 cm apart.
Department of Biomedical Engineering, University of Wisconsin, 600 Highland Avenue, Madison, Wisconsin 53792, USA.
Paul F
PF
Laeseke
Lisa A
LA
Sampson
Tina M
TM
Frey
Rajat
R
Mukherjee
Thomas C
TC
Winter
Fred T
FT
Lee
Chris L
CL
Brace
D000818:Animals; D017115:Catheter Ablation / Q000295:instrumentation* / Q000379:methods; D004567:Electrodes, Implanted; D004867:Equipment Design; D005260:Female; D007668:Kidney / Q000601:surgery*; D016014:Linear Models; D023421:Models, Animal; D012107:Research Design; D034421:Sus scrofa; D013696:Temperature