title: Bimodal electric tissue ablation-long term studies of morbidity and pathological change.
abstract: BACKGROUND
  Radiofrequency ablation is a popular method of treating unresectable liver tumors but tumors greater than 3 cm in diameter have a much greater risk of local recurrence after treatment. Bimodal electric tissue ablation is a modified form of radiofrequency ablation that creates significantly larger ablations by the addition of extra direct current circuitry. This may help to reduce the risk of local recurrence in these larger tumors. Prior to use in a clinical setting, a long term study was performed to assess associated morbidity and the pathological changes in the ablations.
  
  
  METHODS
  In eight pigs, six ablations were performed in each liver. Pigs were euthanized at 2 d, 2 wk, 2 mo, and 4 mo, and the ablations were assessed macroscopically and microscopically for pathological change. Regular blood tests were performed to assess changes in liver function. At death, any other abnormalities detected were reported.
  
  
  RESULTS
  Histopathological examination of ablation zones revealed tissue death by coagulative necrosis and healing by fibrotic scarring. Transient rises in serum liver enzymes were seen in the postoperative period. Skin necrosis was noted at the site of the positive electrode of the direct electrical current but no other form of morbidity was seen associated with the procedure.
  
  
  CONCLUSIONS
  Although the positive electrode placement requires further consideration, bimodal electric tissue ablation appears to be safe and behaves in a similar fashion to other thermal therapies such as standard radiofrequency ablation.
authors.affiliation: Division of Surgery, The Queen Elizabeth Hospital, University of Adelaide, Adelaide, South Australia.
authors.forename: Christopher
authors.initials: C
authors.lastname: Dobbins
authors.forename: Catriona
authors.initials: C
authors.lastname: Brennan
authors.forename: Simon
authors.initials: S
authors.lastname: Wemyss-Holden
authors.forename: John
authors.initials: J
authors.lastname: Cockburn
authors.forename: Guy
authors.initials: G
authors.lastname: Maddern
mesh_terms: D000410:Alanine Transaminase / Q000097:blood; D000469:Alkaline Phosphatase / Q000097:blood; D000818:Animals; D001219:Aspartate Aminotransferases / Q000097:blood; D001663:Bilirubin / Q000097:blood; D017115:Catheter Ablation / Q000009:adverse effects* / Q000379:methods*; D005260:Female; D007770:L-Lactate Dehydrogenase / Q000097:blood; D008099:Liver / Q000378:metabolism / Q000473:pathology* / Q000601:surgery*; D008113:Liver Neoplasms / Q000601:surgery; D009336:Necrosis; D013552:Swine; D013997:Time Factors; D005723:gamma-Glutamyltransferase / Q000097:blood
chemical_list: D007770:L-Lactate Dehydrogenase; D005723:gamma-Glutamyltransferase; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D000469:Alkaline Phosphatase; D001663:Bilirubin