The Influence of Irreversible Electroporation Parameters on the Size of the Ablation Zone and Thermal Effects: A Systematic Review

Abstract

Introduction: The aim of this study was to review the effect of irreversible electroporation parameter settings on the size of the ablation zone and the occurrence of thermal effects. This insight would help to optimize treatment protocols and effectively ablate a tumor while controlling the occurrence of thermal effects. Methods: Various individual studies report the influence of variation in electroporation parameters on the ablation zone size or occurrence of thermal effects. However, no connections have yet been established between these studies. With the aim of closing the gap in the understanding of and personalizing irreversible electroporation parameter settings, a systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A quality assessment was performed using an in-house developed grading tool based on components of commonly used grading domains. Data on the electroporation parameters voltage, number of electrodes, inter-electrode distance, active needle length, pulse length/number/protocol/frequency, and pulse interval were extracted. Ablation zone size and temperature data were grouped per parameter. Spearman correlation and linear regression were used to define the correlation with outcome measures. Results: A total of 7661 articles were screened, of which 18 preclinical studies (animal and phantom studies) met the inclusion criteria. These studies were graded as moderate (4/18) and low (14/18) quality. Only the applied voltage appeared to be a significant linear predictor of ablation zone size: length, surface, and volume. The pulse number was moderately but nonlinearly correlated with the ablation zone length. Thermal effects were more likely to occur for higher voltages (≥2000 V), higher number of electrodes, and increased active needle length. Conclusion: Firm conclusions are limited since studies that investigated and precisely reported the influence of electroporation parameters on the ablation zone size and thermal effects were scarce and mostly graded low quality. High-quality studies are needed to improve the predictability of the combined effect of variation in parameter combinations and optimize irreversible electroporation treatment protocols.

Geometric Anatomy Basis for Safe and Effective Focal Ablation of Prostate Cancer by Irreversible Electroporation (IRE)

“…The needles should be tilted by 10-15° in the sagittal plane to follow the rectal angle and to allow the visualisation of the posterior baso-apical edge basal of After the placement of the needles, the relative distances are checked, along with the active electric pathways which need to be open or excluded to cover the tumour, whilst avoiding redundant electrical pathways (Figure 5). If a high electric field or pulse length is used near the thermal effect zone (Thermal effects > 50 • C can occur along the probes for higher voltages (>2500 V) [18]. (Figure 1), the probes can potentially heat up; therefore, they should be as far away as possible from sensitive anatomical structures such as the rectal wall, urethra or neurovascular bundles.…”

Biphasic Regulation of Apoptosis Following Gastric Irreversible Electroporation Using Tissue Immunohistochemistry of Activated Caspase-3 with TUNEL Method

“…However, IRE employment for tissues depends on the successful manipulation of electrical parameters such as pulse amplitude [10], pulse rate (H-FIRE) [11], electrode arrays with a number of electrodes [12], and tissue conductivity [13], all of which influence the range and depth of IRE. When electrical energy is transferred to tissues, the parameter most affected by the change in the magnitude of the imposed voltage should be prioritized [14].…”