Objective:
Irreversible electroporation (IRE) is a non-thermal ablation technique suitable for tumors near critical structures, but its widespread use is limited by technical complexity and the need for multiple electrodes. This study aimed to evaluate the feasibility, safety, and efficacy of a stereotactic percutaneous two-needle IRE approach for small liver tumors in anatomically challenging locations.

Materials and methods:
In this retrospective study, 17 consecutive patients with 18 primary or secondary liver tumors (≤ 2.0 cm) adjacent to critical anatomical structures underwent CT-navigated stereotactic two-needle IRE between December 2021 and May 2025. Ablation was performed with a high-dose protocol (2 × 90 pulses, 90 µs, > 20 A). Primary endpoints were primary technique efficacy (PTE) and local tumor progression (LTP); secondary endpoints included complications. Needle placement was assessed through geometric analysis.

Results:
PTE was obtained in 17/18 tumors (94.4%, 95% confidence interval (CI): 72.7–99.9%). At a median follow-up of 12.4 months, LTP occurred in 1/18 tumors (5.6%, 95% CI: 0.1–27.3%). No complications or procedure-related mortality were observed. Geometric analysis showed high accuracy of stereotactic needle placement, while treatment failure was associated with suboptimal geometry.

Conclusion:
Stereotactic percutaneous two-needle IRE seems to be technically feasible with a favorable safety profile for small liver tumors in anatomically challenging locations and may offer a simplified alternative to multielectrode approaches. However, given the small, retrospective single-center design, these findings are preliminary and require prospective multicenter validation to establish oncologic effectiveness and generalizability.

Relevance statement:
Stereotactic two-needle irreversible electroporation offered a simplified, safe, and effective alternative to multielectrode ablation, potentially broadening treatment options for liver tumors near critical structures and improving accessibility, reproducibility, and outcomes in interventional oncology.
Key Points

First systematic clinical evaluation of stereotactic two-needle irreversible electroporation (IRE) for liver tumors.

Two-needle configuration with high-dose protocol simplifies IRE compared with standard multielectrode approaches.

This proof-of-concept study demonstrates high efficacy and absence of complications in small liver tumors near critical structures.

Two-needle IRE may broaden clinical applicability in anatomically challenging locations.