Intrahepatic radiofrequency ablation versus electrochemical treatment in vivo.
BACKGROUND
Radiofrequency ablation (RFA) and electrochemical treatment (ECT) are two methods of local liver tumour ablation. The objective of this study was to compare these methods when applied in proximity to vessels in vivo.


METHODS
In a total of ten laparotomised pigs, we used ECT (Group A, four animals) and RFA (Group B, four animals) to create four areas of ablation per animal under ultrasound guidance within 10 mm of a vessel. Group C consisted of two control animals. Chemical laboratory tests were performed immediately before and after each procedure and on days 1, 3 and 7 after surgery. Following the last tests, the livers were harvested for morphological evaluation.


RESULTS
The mean duration of surgery was 5 h 40 min in Group A (ECT), 2 h 47 min in Group B (RFA), and 2 h 30 min in Group C (control animals). After ECT, the harvested livers showed a mean volume of necrosis of 1.84 cm(3) ± 0.88 at the anode and 2.59 cm(3) ± 1.06 at the cathode. The presence of vessels did not influence the formation of necrotic zones. Ablation time was 67 min when a charge of 200 coulombs was delivered. We measured pH values of 1.2 (range: 0.9-1.7) at the anode and 11.7 (range: 11.0-12.1) at the cathode. In one of the 16 RFA ablations (6%), the target temperature was not reached and the procedure was discontinued. After 14 of 16 RFA procedures (88%), morphological analysis showed incomplete ablation in perivascular sites. Both ECT and RFA were associated with a reversible increase in monocyte, C-reactive protein (CRP) and aspartate aminotransferase (AST) levels. There was no significant increase in interleukin-1β (IL-1β), tumour necrosis factor-α (TNF-α) and IL-6.


CONCLUSIONS
In the majority of cases, intrahepatic RFA in vivo leads to incomplete necrosis in proximity to vessels and the presence of histologically intact perivascular cells. Without a reduction in liver perfusion, the central application of RFA should be considered problematic. ECT is a safe alternative. It is not associated with a heat sink effect but has the disadvantage of long treatment times.
Department of Surgery, University of Luebeck Medical School, Ratzeburger Allee 160, Luebeck, Germany.
Ralf
R
Czymek
Jan
J
Nassrallah
Maximilian
M
Gebhard
Andreas
A
Schmidt
Stefan
S
Limmer
Markus
M
Kleemann
Hans-Peter
HP
Bruch
Philipp
P
Hildebrand
D000818:Animals; D017115:Catheter Ablation / Q000379:methods*; D016207:Cytokines / Q000378:metabolism; D053672:Electrochemotherapy / Q000379:methods*; D008099:Liver / Q000098:blood supply / Q000473:pathology* / Q000601:surgery; D008113:Liver Neoplasms / Q000188:drug therapy / Q000601:surgery; D009336:Necrosis / Q000473:pathology; D011897:Random Allocation; D034421:Sus scrofa; D013696:Temperature; D018084:Ultrasonography, Interventional
D016207:Cytokines