title: Determining a minimal safe distance to prevent thermal injury to intrahepatic bile ducts in radiofrequency ablation of the liver: a study in dogs.
abstract: OBJECTIVE
  To determine a minimal safe distance between the radiofrequency ablation (RFA) electrode tip and major intrahepatic bile ducts to prevent thermal injury during hepatic RFA in a canine model.
  
  
  METHODS
  Forty healthy mongrel dogs were randomised equally into four groups based on the distance between the electrode and large intrahepatic bile ducts during RFA of the liver, as follows: 1.0-2.9 mm, 3.0-4.9 mm, 5.0-7.9 mm, or 8.0-10.0 mm. The RFA electrodes were opened uniformly at 2 cm. During RFA, energy was sequentially raised, starting at 5 W and increasing by 5 W increments every minute to a maximum of 95 W. Animals were monitored for a maximum of 14 days post-RFA for complications and by bilirubin testing, after which they were euthanised and their livers were surgically removed for cholangiographic and pathological examination.
  
  
  RESULTS
  When the electrodes were less than 5.0 mm from the bile ducts during RFA, either full or partial-thickness bile duct necrosis occurred, leading to a variety of serious complications. In contrast, when the distance was more than 5.0 mm between the RFA electrode and bile ducts, serious complications occurred rarely, with pathological examinations showing either normal bile ducts or vacuolar changes of the biliary ductal epithelium.
  
  
  CONCLUSIONS
  A minimum safe distance of 5.0 mm between the RFA electrode and intrahepatic bile ducts was effective in preventing serious complications secondary to bile duct injury in a canine model.
authors.affiliation: Institute of Hepatobiliary Surgery, Southwest Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Nianzhou
authors.initials: N
authors.lastname: Liu
authors.forename: Jun
authors.initials: J
authors.lastname: Gao
authors.forename: Yongkang
authors.initials: Y
authors.lastname: Liu
authors.forename: Tingjun
authors.initials: T
authors.lastname: Li
authors.forename: Kai
authors.initials: K
authors.lastname: Feng
authors.forename: Kuansheng
authors.initials: K
authors.lastname: Ma
authors.forename: Jiahong
authors.initials: J
authors.lastname: Dong
authors.forename: Xiaowu
authors.initials: X
authors.lastname: Li
authors.forename: Shuguang
authors.initials: S
authors.lastname: Wang
authors.forename: Ping
authors.initials: P
authors.lastname: Bie
mesh_terms: D000818:Animals; D001652:Bile Ducts / Q000473:pathology; D001653:Bile Ducts, Intrahepatic / Q000528:radiation effects / Q000601:surgery*; D001663:Bilirubin / Q000378:metabolism; D017115:Catheter Ablation / Q000009:adverse effects / Q000379:methods*; D004285:Dogs; D005260:Female; D008099:Liver / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D023421:Models, Animal; D011833:Radiation Injuries, Experimental / Q000473:pathology; D011859:Radiography
chemical_list: D001663:Bilirubin