Radiofrequency ablation of rabbit liver in vivo: effect of the pringle maneuver on pathologic changes in liver surrounding the ablation zone.
OBJECTIVE
We wished to evaluate the effect of the Pringle maneuver (occlusion of both the hepatic artery and portal vein) on the pathologic changes in the hepatic vessels, bile ducts and liver parenchyma surrounding the ablation zone in rabbit livers.


METHODS
Radiofrequency (RF) ablation zones were created in the livers of 24 rabbits in vivo by using a 50-W, 480-kHz monopolar RF generator and a 15-gauge expandable electrode with four sharp prongs for 7 mins. The tips of the electrodes were placed in the liver parenchyma near the porta hepatis with the distal 1 cm of their prongs deployed. Radiofrequency ablation was performed in the groups with (n=12 rabbits) and without (n=12 rabbits) the Pringle maneuver. Three animals of each group were sacrificed immediately, three days (the acute phase), seven days (the early subacute phase) and two weeks (the late subacute phase) after RF ablation. The ablation zones were excised and serial pathologic changes in the hepatic vessels, bile ducts and liver parenchyma surrounding the ablation zone were evaluated.


RESULTS
With the Pringle maneuver, portal vein thrombosis was found in three cases (in the immediate [n=2] and acute phase [n=1]), bile duct dilatation adjacent to the ablation zone was found in one case (in the late subacute phase [n=1]), infarction adjacent to the ablation zone was found in three cases (in the early subacute [n=2] and late subacute [n=1] phases). None of the above changes was found in the livers ablated without the Pringle maneuver. On the microscopic findings, centrilobular congestion, sinusoidal congestion, sinusoidal platelet and neutrophilic adhesion, and hepatocyte vacuolar and ballooning changes in liver ablated with Pringle maneuver showed more significant changes than in those livers ablated without the Pringle maneuver (p < 0.05)


CONCLUSIONS
Radiofrequency ablation with the Pringle maneuver created more severe pathologic changes in the portal vein, bile ducts and liver parenchyma surrounding the ablation zone compared with RF ablation without the Pringle maneuver. Therefore, we suggest that RF ablation with the Pringle maneuver should be performed with great caution in order to avoid unwanted thermal injury.
Kim
Seung Kwon
SK
Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Kangnam-gu, Seoul, Korea.
Lim
Hyo K
HK
Ryu
Jeong-ah
JA
Choi
Dongil
D
Lee
Won Jae
WJ
Lee
Ji Yeon
JY
Lee
Ju Hyun
JH
Sung
Yon Mi
YM
Cho
Eun Yoon
EY
Hong
Seung-Mo
SM
Kim
Jong-Sung
JS
D000818:Animals; D001652:Bile Ducts / Q000473:pathology* / Q000601:surgery; D017115:Catheter Ablation; D004195:Disease Models, Animal; D006499:Hepatic Artery / Q000473:pathology* / Q000601:surgery; D008099:Liver / Q000098:blood supply* / Q000473:pathology / Q000601:surgery*; D008297:Male; D009336:Necrosis; D011169:Portal Vein / Q000473:pathology; D011817:Rabbits