title: In-vivo evaluation of a novel bipolar radiofrequency device for interstitial thermotherapy of liver tumors during normal and interrupted hepatic perfusion.
abstract: BACKGROUND
  Only monopolar systems have thus far been available for radiofrequency ablation of liver tumors, whose application is restricted because of the incalculable energy flow, reduction of electrical tissue conduction, and limited lesion size. The aim of this study was to evaluate a novel internally cooled bipolar radiofrequency application device under in vivo conditions and to compare the effect of this system on lesion size when combined with hepatic arterial microembolization or complete hepatic blood flow occlusion.
  
  
  METHODS
  In a porcine liver model, RFA (60 W, 12 min) was performed with either normal (n = 12), partially interrupted (arterial microembolization via a hepatic artery catheter n = 12) or completely interrupted hepatic perfusion (Pringle's maneuver, n = 12). RFA parameters (impedance, power output, temperature, applied energy) were determined continuously during therapy. RFA lesions were macroscopically assessed after liver dissection.
  
  
  RESULTS
  Bipolar RFA induced clinical relevant ellipsoid thermal lesions without complications. Hepatic inflow occlusion led to a 4.3-fold increase in lesion volume after arterial microembolization and a 5.8-fold increase after complete interruption (7.4 cm(3)versus 31.9 cm(3)versus 42.6 cm(3), P < 0.01).
  
  
  CONCLUSIONS
  The novel bipolar RFA device is a safe and effective alternative to monopolar RFA-systems. Interrupting hepatic perfusion significantly increases lesion volumes in bipolar RFA. This beneficial effect can also be achieved in the percutaneous application mode by RFA combined with arterial microembolization via a hepatic artery catheter.
authors.affiliation: Department of General, Vascular and Thoracic Surgery, University Medicine Berlin, Campus Benjamin Franklin, Berlin, Germany. joerg-peter.ritz@charite.de
authors.forename: Joerg-P
authors.initials: JP
authors.lastname: Ritz
authors.forename: Kai S
authors.initials: KS
authors.lastname: Lehmann
authors.forename: Christoph
authors.initials: C
authors.lastname: Isbert
authors.forename: Christoph
authors.initials: C
authors.lastname: Reissfelder
authors.forename: Thomas
authors.initials: T
authors.lastname: Albrecht
authors.forename: Thomas
authors.initials: T
authors.lastname: Stein
authors.forename: Heinz J
authors.initials: HJ
authors.lastname: Buhr
mesh_terms: D000818:Animals; D017115:Catheter Ablation / Q000295:instrumentation* / Q000379:methods; D004621:Embolization, Therapeutic; D006499:Hepatic Artery; D006979:Hyperthermia, Induced / Q000295:instrumentation* / Q000379:methods; D008099:Liver / Q000098:blood supply / Q000601:surgery; D008102:Liver Circulation; D008113:Liver Neoplasms / Q000556:secondary / Q000601:surgery*; D008297:Male; D008833:Microcirculation; D008863:Microspheres; D013213:Starch; D034421:Sus scrofa
chemical_list: D013213:Starch