Stent-based and catheter-based endobiliary radiofrequency ablation for malignant biliary obstruction: an ex-vivo comparative study

Endobiliary radiofrequency ablation (RFA) is used as an adjunct therapy to improve local tumor control and stent patency; however, catheter-based RFA may result in non-uniform ablation in curved or tortuous ducts because of incomplete electrode–wall contact. This study compared stent-based electrodes with conventional catheter-based electrodes using a curved endoluminal phantom and ex-vivo porcine liver tissue. In the curved phantom, the catheter-based electrode showed curvature-dependent asymmetry, with higher macroscopic ablation grades at the lesser curvature than at the greater curvature (2.1 ± 0.73 vs. 1.1 ± 0.73; p = 0.009). In contrast, the use of the stent-based electrode resulted in more uniform ablation regardless of the curvature (2.2 ± 0.42 vs. 2.3 ± 0.48; p = 0.624). The stent-based electrode generated larger macroscopic ablation zones than the catheter-based electrode, with greater histological central and peripheral zones (all p < 0.001). The stent-based endobiliary RFA system demonstrated larger and more uniform ablation zones compared with the catheter-based system in ex-vivo and phantom models. Stent-based electrodes may overcome key limitations of catheter-based electrodes, particularly in anatomically curved or tortuous ducts, by improving electrode–tissue contact and ablation uniformity.