Can electroporation previous to radiofrequency hepatic ablation enlarge thermal lesion size? A feasibility study based on theoretical modelling andin vivoexperiments

Abstract

Castellvi, Q.; Burdío, F.; Sánchez Velázquez, P.; Ivorra, A.; Andaluz, A.; Berjano, E. (2013). Can electroporation previous to radiofrequency hepatic ablation enlarge thermal lesion size? A feasibility study based on theoretical modelling and in vivo experiments. AbstractPurpose: To assess the feasibility of a hybrid ablative technique based on applying electroporation (EP) pulses just before conducting radiofrequency ablation (RFA). The rationale was that the EP-induced reduction in blood perfusion could be sufficient to reduce the thermal sink effect and hence to increase the coagulation volume in comparison to that created exclusively by RFA. Materials and methods:Modeling study and in vivo experimental study. A Cool-tip RF applicator was used both for EP and RFA.Results: Overall, the results did not show any synergy effect from using the hybrid technique. Applying EP pulses prior to RFA did not increase the coagulation zone obtained and the lesions were almost identical. Additional computer simulations provided an explanation for this; the effect of reducing blood perfusion by thermal damage during RFA completely masks the effect of reducing blood perfusion by EP. This is because both thermal damage and EP affect the same zone, i.e. the tissue around the electrode. Conclusions:Our computer modeling and in vivo experimental findings suggest that the combination of EP and RFA with monopolar applicators does not provide an additional benefit over the use of RFA alone.

Effect of applied voltage, duration and repetition frequency of RF pulses for pain relief on temperature spikes and electrical field: a computer modelling study

“…where q is the density of tissue, c is the specific heat, k is the thermal conductivity, T is the temperature, t is the time, q is the heat source generated by RF power, Q m is the metabolic heat generation (not considered in RF ablation) and Q p is the heat loss from blood perfusion described as of values 1000 kg/m 3 and 4180 J/(kgÁK), respectively and T a is the temperature of the arterial blood (37 C) [25]. The heat source q was taken from the electrical problem and evaluated as q ¼ J Á E, where J is the current density, which is obtained from J ¼ r E. No blood perfusion was assumed when tissue reached a 99% probability of thermal necrosis.…”

On Understanding of the Limiting Factors in Radiofrequency Ablation on Target Tissue Necrosis Volume

“…Of them, obtaining a large TTN volume is of vital importance for the treatment of target tissue 3 cm in diameter. To date, many researchers have attempted to achieve a large TTN volume using the methods, including new designs of the RF electrode [8,9], an algorithm for regulating RF power delivery [10,11], and combination of these two with other methods [12,13].…”