Water-cooled microwave ablation array for bloodless rapid transection of the liver

Microwaves (MWs) deliver relatively high temperatures into biological tissue and cover a large ablation zone. This study aims to evaluate the efficacy and effectiveness of water-cooled double-needle MW ablation arrays in assisting the hepatic transection of an in vivo pig model.

Our research program comprised computer modeling, tissue-mimicking phantom experiments, and in vivo pig liver experiments. Computer modeling was based on the finite element method (FEM) to evaluate ablation temperature distributions. In tissue-mimicking phantom and in vivo pig liver ablation experiments, the performances of the water-cooled MW ablation array and conventional clamp crushing liver resection were compared.

FEM showed that the maximum lateral ablation diameter at 100 W output and a duration of 60 s was 3 cm (assessed at 50 °C isotherm). In the phantom, the maximum transverse ablation diameter of the double-needle MW ablation increased rapidly to 3 cm in 60 s at 50 W. The blood loss and blood loss per transection area in Group A were significantly lower than those in Group B (18 (7-26) ml vs. 34 (19-57) ml, and 2.4 (2-3.1) ml/cm² vs. 6.9 (3.2-8.3) ml/cm², respectively) (p < 0.05). The transection speed in Group A (2.6(1.9-3.8) cm²/min) was significantly faster than that in Group B (1.7(1.1-2.2) cm²/min) (p < 0.05).

In this experimental model, the new water-cooled MW array-assisted liver resection (LR) has the potential advantage of less blood loss and rapid removal than the conventional LR.