Breaking the needle diameter limit for radiofrequencythermal ablation for hepatocellular carcinoma. A new technique

ABSTRACT

A significant number of hepatocellular carcinomas are meet with beyond the ablation field of yet available needles. A new technique had been attempted to increase the field of radiofrequency ablation of expandable electrode needles in the treatment of hepatic neoplasms much larger than the routinely covered size of 5-7 cm according to the needle size overcoming the technical difficulties usually met with in the overlapping balls technique due to the hyperechoic focus that develops at the needle tip making reinsertion difficult and inaccurate. 40 patients were included in the study, all presented with hepatic neoplastic mass lesion that range in size between 7 and 10 cm in its maximum diameter. In this technique, two or three needles were inserted from the start into the mass with accurate estimation of the exact field of ablation of each needle trying to cover the whole extent of the mass before application of radiofrequency waves. All had a pretreatment helical [triphasic] CT study for accurate delineation of the whole extent and vascularity of the mass. Two needles were sufficient to cover the whole extent of the mass in 23 patients [57%] while in the remaining 17 patients [43%] three needles were necessary. The procedure was done under general anathesia and ultrasound guidance, patients tolerated procedure well with smooth recovery. No major complications. Follow up spiral [triphasic] CT was done 2 weeks after ablation revealed percentage of tumour necrosis of 90% or more in 30 patients [75%], 70-90% in 6 patients [15%] while in the remaining four patients [10%] the percentage was 50-70% necrosis. In conclusion this technique should be considered in the treatment of hepatic masses larger than the usual field of the needle