title: Novel laparoscopic bipolar radiofrequency energy technology for expedited hepatic tumour ablation.
abstract: BACKGROUND
  Monopolar radiofrequency ablation (RFA) is a well accepted modality for local control of hepatic tumours, but its effectiveness is challenged by prolonged ablation time, an inconsistent ablation zone and susceptibility to energy loss from convective heat loss from adjacent high-velocity blood flows ('heat sinks'). Bipolar RFA employs a dual parallel electrode array; the energy wave travels unidirectionally between and not around electrodes. This 'line-of-sight' delivery streams energy between two fixed points and concentrates energy delivery to the area between the probes. Bipolar RFA is postulated to yield reduced ablation time and to reduce or eliminate convective heat loss from adjacent high-velocity blood flows. The current study evaluated the feasibility, time and safety of this novel FDA-approved bipolar RFA technology using a laparoscopic approach in human liver tumours.
  
  
  METHODS
  Using the prospectively maintained surgical oncology hepatic-pancreatic-biliary database, 17 consecutive patients (26 liver tumours) who underwent laparoscopic bipolar ablations were reviewed. Electrodes were placed using guidance by intraoperative ultrasound and trajectory planning needles. Ablation time was recorded and postoperative computed tomography scans were obtained.
  
  
  RESULTS
  A total of 18 lesions (in 12 patients) represented metastatic colorectal cancer. Three lesions (in two patients) were hepatocellular carcinoma. Four lesions (in two patients) represented locally advanced symptomatic gallbladder cancer invading the liver bed or symptomatic intrahepatic liver metastases from gallbladder cancer. One lesion was benign hepatic adenoma. Mean tumour size was 3.07 +/- 1.42 cm. Mean ablation time was 358 +/- 120 sec. No major complications were observed in the < or = 30-day or >30-day periods post-RFA.
  
  
  CONCLUSIONS
  Laparoscopic bipolar RFA is a quick, safe technique which adds a new tool to our armamentarium for treating hepatic tumours. Establishing its longterm oncological outcome will require longer follow-up and the exact role of this technique in the current multimodality management remains to be defined.
authors: Hepatobiliary and Surgical Oncology, Roger William Medical Center, Providence, RI 02908, USA.
authors: Bing
authors: B
authors: Yi
authors: Ponnandai
authors: P
authors: Somasundar
authors: N Joseph
authors: NJ
authors: Espat