Laparoscopic radiofrequency ablation of solitary small hepatocellular carcinoma in the caudate lobe

Multipolar versus monopolar radiofrequency ablation for hepatocellular carcinoma in the caudate lobe: Results of a propensity score analysis

“…Hepatocellular carcinomas in the caudate lobe are most likely associated with portal venous infiltration and/or venous infiltration through the short hepatic veins, thus, they readily develop intrahepatic metastases . Especially in the caudate lobe, insufficient ablation should be avoided to prevent portal venous infiltration and/or venous infiltration through the short hepatic veins.…”

“…One of the mechanisms is heat loss, well known as the HSE of the inferior vena cava. The HSE becomes substantial in a tumor only 5 mm or less adjacent to a large blood vessel . The electrical current flows from the monopolar electrode to the grounding pad.…”

“…[Color figure can be viewed at wileyonlinelibrary.com] venous infiltration through the short hepatic veins, thus, they readily develop intrahepatic metastases. 12 Especially in the caudate lobe, insufficient ablation should be avoided to prevent portal venous infiltration and/or venous infiltration through the short hepatic veins. Nishigaki et al reported that the local recurrence rate after RFA was significantly higher in the caudate group (22.3%) than in the non-caudate group (4.5%).…”

“…The reasons for the high incidence of local recurrence are several. Single puncture with monopolar RF technology shows limited ability to reliably create a volume of coagulation necrosis because of the heat sink effect (HSE) . To achieve an adequate safety margin using a monopolar electrode, multiple overlapping ablations are required with several sessions .…”

“…Single puncture with monopolar RF technology shows limited ability to reliably create a volume of coagulation necrosis because of the heat sink effect (HSE). 11,12 To achieve an adequate safety margin using a monopolar electrode, multiple overlapping ablations are required with several sessions. 13 Repositioning the monopolar electrode under ultrasonographic percutaneous procedures, often carried out under 2-D guidance, is very difficult, because the hyperechoic area changed by the previous ablation may interfere with locating the tip of the electrode and identifying unablated residual tumor.…”