title: Intrahepatic radiofrequency ablation versus electrochemical treatment ex vivo.
abstract: BACKGROUND
  Radiofrequency ablation (RFA) and electrochemical treatment (ECT) are two methods of local liver tumor ablation. A reproducible perfusion model allowed us to compare these methods when applied in proximity to vascular structures.
  
  
  METHODS
  In a porcine liver perfusion model, we used RFA (group A) and ECT (group B) to perform ablations under ultrasound guidance within 10 mm of a vessel and examined the induced necrosis macroscopically and histologically.
  
  
  RESULTS
  We created 83 lesions (RFA: 59, ECT: 24) in 27 livers. In group A (mean liver weight: 2046 g), perfusion was macroscopically found to limit necrosis in 52.5% of the procedures. Histology demonstrated the destruction of only 30.4% of the vessel walls within the ablation areas. In group B (mean liver weight: 1885 g), we detected reproducible and sharply demarcated ablation areas both macroscopically and histologically. Necrosis was unaffected by nearby vessels. No viable cells were found perivascularly. Histology showed destruction of the vascular endothelium without any discontinuities. We measured pH values of 0.9 (range: 0.6-1.8) at the anode and 12.2 (range: 11.4-12.6) at the cathode. Treatment time was 100 min when a charge of 300 coulombs was delivered.
  
  
  CONCLUSIONS
  Electrochemical treatment is a method of ablation that creates reproducible and predictable volumes of necrosis. It produces sharply demarcated areas of complete necrosis also in perivascular sites. ECT, however, requires much longer treatment times than RFA. In our model, the effects of RFA were considerably limited by perfusion, which caused incomplete areas of necrosis in proximity to vessels.
authors.affiliation: Department of Surgery, University of Luebeck Medical School, Luebeck, Germany. ralf_czymek@web.de
authors.forename: Ralf
authors.initials: R
authors.lastname: Czymek
authors.forename: Stefan
authors.initials: S
authors.lastname: Loeffler
authors.forename: Dorothea
authors.initials: D
authors.lastname: Dinter
authors.forename: Maximilian
authors.initials: M
authors.lastname: Gebhard
authors.forename: Andreas
authors.initials: A
authors.lastname: Schmidt
authors.forename: Thomas
authors.initials: T
authors.lastname: Jungbluth
authors.forename: Markus
authors.initials: M
authors.lastname: Kleemann
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Bruch
authors.forename: Andreas
authors.initials: A
authors.lastname: Lubienski
mesh_terms: D000818:Animals; D017115:Catheter Ablation / Q000379:methods*; D055664:Electrochemical Techniques; D006863:Hydrogen-Ion Concentration; D008113:Liver Neoplasms / Q000473:pathology / Q000628:therapy*; D009336:Necrosis; D013552:Swine