Irreversible Electroporation: A New Ablation Modality — Clinical Implications

TLDR

Irreversible electroporation (IRE) is a novel ablation modality that delivers micro‑ to millisecond electrical pulses to induce cell necrosis through irreversible membrane permeabilization, affecting only the cell membrane and sparing other tissue structures. The study aimed to evaluate the IRE protocol in pig liver, report long‑term histopathology, and assess its clinical implications. The authors designed an IRE protocol via mathematical electric‑field analysis, positioned electrodes with ultrasound guidance, applied the pulses, performed histopathology up to two weeks post‑treatment, and correlated the mathematical predictions, ultrasound data, and histological findings. Real‑time ultrasound imaging confirmed precise ablation to lesion margins, complete vessel‑adjacent tissue destruction without compromising vessel integrity, preservation of bile ducts and connective tissue, rapid lesion resolution within two weeks, evidence of an immunologic response, and validated Laplace‑equation predictions for treatment planning, indicating IRE’s promise as a new surgical tool.

Abstract

Irreversible electroporation (IRE) is a new tissue ablation technique in which micro to millisecond electrical pulses are delivered to undesirable tissue to produce cell necrosis through irreversible cell membrane permeabilization. IRE affects only the cell membrane and no other structure in the tissue. The goal of the study is to test our IRE tissue ablation methodology in the pig liver, provide first experience results on long term histopathology of IRE ablated tissue, and discuss the clinical implications of the findings. The study consists of: a) designing an IRE ablation protocol through a mathematical analysis of the electrical field during electroporation; b) using ultrasound to position the electroporation electrodes in the predetermined locations and subsequently to monitor the process; c) applying the predetermined electrotroporation pulses; d) performing histolopathology on the treated samples for up to two weeks after the procedure; and e) correlating the mathematical analysis, ultrasound data, and histology. We observed that electroporation affects tissue in a way that can be imaged in real time with ultrasound, which should facilitate real time control of electroporation during clinical applications. We observed cell ablation to the margin of the treated lesion with several cells thickness resolution. There appears to be complete ablation to the margin of blood vessels without compromising the functionality of the blood vessels, which suggests that IRE is a promising method for treatment of tumors near blood vessels (a significant challenge with current ablation methods). Consistent with the mechanism of action of IRE on the cell membrane only, we show that the structure of bile ducts, blood vessels, and connective tissues remains intact with IRE. We report extremely rapid resolution of lesions, within two weeks, which is consistent with retention of vasculature. We also document tentative evidence for an immunological response to the ablated tissue. Last, we show that mathematical predictions with the Laplace equation can be used in treatment planning. The IRE tissue ablation technique, as characterized in this report, may become an important new tool in the surgeon armamentarium.