Ex vivo comparison between thyroid-dedicated bipolar and monopolar radiofrequency electrodes

Area of Science:

• Radiology
• Surgical Technology
• Biomedical Engineering

Background:

• Radiofrequency ablation (RFA) is a minimally invasive technique used for tumor ablation.
• Optimizing RFA electrode design is crucial for improving ablation efficacy and patient outcomes.
• Bipolar radiofrequency electrodes (BRFE) offer potential advantages over traditional monopolar RF electrodes (MRFEs).

Purpose of the Study:

• To evaluate the characteristics and ablation performance of a thyroid-dedicated bipolar RF electrode (BRFE).
• To compare the ablation performance of BRFE with that of monopolar RF electrodes (MRFEs) in bovine liver tissue.
• To assess the impact of different power and time settings on BRFE ablation characteristics.

Main Methods:

• BRFE performance was initially assessed using 60 bovine liver blocks under various time-power combinations (20-40W for 60-120s).
• Subsequently, BRFE and MRFEs (0.5, 0.7, 1-cm tips) were applied to 160 liver blocks, creating 16 time-electrode combinations (10-120s).
• Ablation characteristics, RF efficacy, and true RF efficacy (ablation volume per valid RF current time) were evaluated and compared.

Main Results:

• BRFE demonstrated significantly larger vertical and transverse ablation diameters compared to MRFEs with 0.5-cm tips (p < 0.001).
• MRFEs with 0.7-cm tips produced larger ablation volumes, efficacy, and true efficacy than BRFE (p = 0.011).
• BRFE consistently yielded a higher shape ratio, indicating more ellipsoid lesions, compared to MRFEs with 0.5-cm and 0.7-cm tips (p < 0.001).

Conclusions:

• BRFE with 30W at 60s achieved ablation volumes and efficacy intermediate to MRFEs with 0.5-cm and 0.7-cm tips.
• BRFE consistently produced more ellipsoid-shaped ablation zones compared to MRFEs.
• The findings suggest BRFE offers distinct ablation characteristics that may be advantageous in specific clinical applications, particularly when lesion shape is critical.