Comparison between different thickness umbrella-shaped expandable radiofrequency electrodes (SuperSlim and CoAccess): Experimental and clinical study

Abstract

Abstract. The purpose of the present study was to compare the size and configuration of the ablation zones created by SuperSlim and CoAccess electrodes, using various ablation algorithms in ex vivo bovine liver and in clinical cases. In the experimental study, we ablated explanted bovine liver using 2 types of electrodes and 4 ablation algorithms (combinations of incremental power supply, stepwise expansion and additional low-power ablation) and evaluated the ablation area and time.In the clinical study, we compared the ablation volume and the shape of the ablation zone between both electrodes in 23 hepatocellular carcinoma (HCC) cases with the best algorithm (incremental power supply, stepwise expansion and additional low-power ablation) as derived from the experimental study. In the experimental study, the ablation area and time by the CoAccess electrode were significantly greater compared to those by the SuperSlim electrode for the single-step (algorithm 1, p=0.0209 and 0.0325, respectively) and stepwise expansion algorithms (algorithm 2, p=0.0002 and <0.0001, respectively; algorithm 3, p= 0.006 and 0.0407, respectively). However, differences were not significant for the additional low-power ablation algorithm. In the clinical study, the ablation volume and time in the CoAccess group were significantly larger and longer, respectively, compared to those in the SuperSlim group (p=0.0242 and 0.009, respectively). Round ablation zones were acquired in 91.7% of the CoAccess group, while irregular ablation zones were obtained in 45.5% of the SuperSlim group (p= 0.0428). In conclusion, the CoAccess electrode achieves larger and more uniform ablation zones compared with the SuperSlim electrode, though it requires longer ablation times in experimental and clinical studies.

Novel Approaches to Treatment of Hepatocellular Carcinoma and Hepatic Metastases Using Thermal Ablation and Thermosensitive Liposomes

“…6 To minimize the number of percutaneous insertions and expand the volume of tissue encompassed within an array, RF electrodes are available that deploy multiple tines curving out into surrounding tissue like an umbrella from a central larger electrode. 7 …”

Radiofrequency ablation with four electrodes as a building block for matrix radiofrequency ablation: Ex vivo liver experiments and finite element method modelling. Influence of electric and activation mode on coagulation size and geometry

“…Since 1992, new RFA electrodes with ingenious designs (wet, cooled, expandable, bipolar, cooled-wet) and combinations of these designs [7], more powerful generators [8] and improved treatment protocols such as pulsed RFA [9], stepwise deployment of expandable electrodes [10], stepwise increase of current [11,12] and rapid switching between multiple electrodes [13] have been introduced to successfully increase mean ablation diameter, butunfortunately attention to improve predictability of the size and the shape of the ablation zone has lagged behind. Ablation zones are often smaller or larger than expected and less symmetrical, less spherical and less regular than desired [12,. A standard deviation of the ablation diameter, especially the transverse diameter, of 0.5 -1 cm is very common [51].…”

Temperature Profiling of ex-vivo Organs during Ferromagnetic Nanoparticles-Enhanced Radiofrequency Ablation by Fiber Bragg Grating Arrays

“…Moreover, it is necessary to achieve a dense thermal profiling in situ, in order to estimate the size of successfully ablated tissue. Current thermal monitoring techniques rely mostly on electrical thermocouples (TCs) [7,8]; however, their slow response time and inability to provide sufficient sensing density limit application of thermocouples for RF thermal mapping. Another drawback is that thermocouples measure the temperature only in the region reached by RF applicator, rather than on the peripheral sides of the tumor.…”