Radiofrequency ablation using injectable cooled electrode: the effects of lidocaine injection in ex vivo study

Background Pain control is needed during radiofrequency ablation in musculoskeletal tumor. The effect of radiofrequency ablation can be modulated by lidocaine injection. Purpose To evaluate the effects of injectable electrodes with intralesional lidocaine injection and compare its ablation performance with that of non-injectable electrodes in ex vivo pork sirloin. Material and Methods Five specimen groups were used to investigate the effects of fluid injection before radiofrequency ablation using injectable and non-injectable electrodes: three injectable electrode comparison groups with 2% lidocaine (group A); 1% lidocaine (group B); 0.9% sodium chloride (group C); injectable electrode reference group without fluid (group D); and non-injectable electrode control group (group E). The injectable and non-injectable electrodes were 17-gauge electrodes each having a 1-cm active tip. Technical parameters, ablation size, and volumes were compared between the five groups. Results Mean energies and currents during radiofrequency ablation were significantly lower for the four injectable electrode groups compared to group E (all P < 0.005). Two transverse diameters, vertical diameter, and volumes in the four injectable electrode groups were significantly smaller than those in group E (all P < 0.05). Among the injectable electrode groups, volumes and two transverse diameters were significantly smaller in group A than in group D (all P < 0.05). Conclusions A slightly smaller ablation zone is obtained when lidocaine injection is performed before radiofrequency ablation using an injectable electrode compared to a non-injectable electrode.