title: Microwave ablation of malignant hepatic tumours: intraperitoneal fluid instillation prevents collateral damage and allows more aggressive case selection.
abstract: OBJECTIVE
  Theaim of this peper was to retrospectively review our experience utilising protective fluid instillation techniques during percutaneous microwave ablation of liver tumours to determine if fluid instillation prevents non-target injuries and allows a more aggressive case selection.
  
  
  METHODS
  This institute review board-approved, U.S. Health Insurance Portability and Accountability Act-compliant, retrospective study reviewed percutaneous microwave ablation of 151 malignant hepatic tumours in 87 patients, comparing cases in which protective fluid instillation was performed with those where no fluid was utilised. In cases utilising hydrodisplacement for bowel protection, a consensus panel evaluated eligibility for potential ablation without hydrodisplacement. Patient age, tumour size, local tumour progression rate, length of follow-up, complications, displacement distance/artificial ascites thickness, and treatment power/time were compared.
  
  
  RESULTS
  Fluid administration was utilised during treatment in 29/151 of cases: 10/29 for protection of bowel (8/10 cases not possible without fluid displacement), and 19/29 for body wall/diaphragm protection. Local tumour progression was higher when hydrodisplacement was used to protect bowel tissue; this may be due to lower applied power due to operator caution. Local tumour progression was not increased for artificial ascites. There was no difference in complications between the fluid group and controls.
  
  
  CONCLUSIONS
  Intraperitoneal fluid administration is a safe and effective method of protecting non-target structures during percutaneous hepatic microwave ablation. While hydrodisplacement for bowel protection allows more aggressive case selection, these cases were associated with higher rates of local tumour progression.
authors.affiliation: Department of Radiology, University of Wisconsin , Madison, Wisconsin , USA.
authors.forename: Douglas
authors.initials: D
authors.lastname: Kitchin
authors.forename: Meghan
authors.initials: M
authors.lastname: Lubner
authors.forename: Tim
authors.initials: T
authors.lastname: Ziemlewicz
authors.forename: J Louis
authors.initials: JL
authors.lastname: Hinshaw
authors.forename: Marci
authors.initials: M
authors.lastname: Alexander
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Brace
authors.forename: Fred
authors.initials: F
authors.lastname: Lee
mesh_terms: D055011:Ablation Techniques / Q000379:methods*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001202:Ascitic Fluid; D006528:Carcinoma, Hepatocellular / Q000601:surgery*; D005260:Female; D006801:Humans; D007274:Injections, Intraperitoneal; D008113:Liver Neoplasms / Q000601:surgery*; D008297:Male; D008872:Microwaves / Q000627:therapeutic use*; D008875:Middle Aged
keywords: Clinical trials – thermal ablation; radiofrequency/microwave; thermal ablation