Optimizing Irreversible Electroporation Ablation with a Bipolar Electrode.

Abstract Purpose To optimize single-insertion bipolar irreversible electroporation (IRE) by characterizing effects of electric parameters and controlling tissue electric properties in a porcine model. Materials and Methods Single-insertion electrode bipolar IRE was performed in 28 in vivo pig livers (78 ablations). First, effects of voltage (2,700–3,000 V), number of pulses, repeated cycles (1–6 cycles), and pulse width (70–100 µs) were studied. Next, electric conductivity was altered by instillation of hypertonic and hypotonic fluids. Finally, effects of thermal stabilization were assessed using internal electrode cooling. Treatment effect was evaluated 2–3 hours after IRE. Dimensions were compared and subjected to statistical analysis. Results Delivering 3,000 V at 70 µs for a single 90-pulse cycle yielded 3.8 cm ± 0.4 × 2.0 cm ± 0.3 of ablation. Applying 6 cycles of energy increased ablation to 4.5 cm ± 0.4 × 2.6 cm ± 0.3 ( P P P Conclusions Bipolar IRE ablation zones can be increased with repetitive high voltage and greater pulse widths accompanied by either judicious instillation of hypotonic fluids or internal electrode perfusion to minimize unwanted electric arcing.