title: Microwave ablation of hepatic tumors abutting the diaphragm is safe and effective.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the incidence of clinically significant diaphragmatic injuries and local tumor progression after microwave ablation of hepatic tumors abutting the diaphragm.
  
  
  METHODS
  This retrospective study included 55 peripheral hepatic tumors abutting the diaphragm treated by microwave ablation versus a control group of 15 centrally located tumors. Treated tumors were further subdivided according to the use of artificial ascites (fluid vs no fluid) and whether instilled fluid achieved displacement of the liver surface away from the diaphragm (displaced vs nondisplaced). Measurements of tumor size, distance to the diaphragm, ablation zone size, displacement distance, length of the ablation zone along the liver capsule, diaphragm thickness, diaphragmatic hernia, and local tumor progression were made on pre- and postablation CT and MRI. The electronic medical record was reviewed for patient self-reported pain scores and other symptoms. Data were analyzed by use of the Kruskal-Wallis and Fisher exact tests.
  
  
  RESULTS
  There were no cases of diaphragmatic hernia in peripheral or central tumors. Postablation diaphragm thickness was higher in peripheral hepatic tumors than in control tumors. Peripheral tumors had an overall higher incidence of postprocedure shoulder pain (18% vs 0%) and local tumor progression (5.5% vs 0%) compared with control tumors, but these differences did not achieve statistical significance (p = 0.2 and p = 1, respectively).
  
  
  CONCLUSIONS
  Our study shows that microwave ablation of peridiaphragmatic hepatic tumors is safe, without incidence of diaphragmatic hernia, and can be performed with a low rate of local tumor progression.
authors.affiliation: 1 Department of Radiology, University of Wisconsin School of Medicine and Public Health, 600 Highland Ave, MC 3252, Madison, WI 53792.
authors.forename: Amanda R
authors.initials: AR
authors.lastname: Smolock
authors.forename: Meghan G
authors.initials: MG
authors.lastname: Lubner
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Ziemlewicz
authors.forename: J Louis
authors.initials: JL
authors.lastname: Hinshaw
authors.forename: Douglas R
authors.initials: DR
authors.lastname: Kitchin
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Brace
authors.forename: Fred T
authors.initials: FT
authors.lastname: Lee
mesh_terms: D017115:Catheter Ablation / Q000009:adverse effects* / Q000379:methods*; D005260:Female; D006548:Hernia, Diaphragmatic / Q000000981:diagnostic imaging / Q000209:etiology* / Q000517:prevention & control*; D006801:Humans; D008113:Liver Neoplasms / Q000150:complications / Q000000981:diagnostic imaging / Q000628:therapy*; D008297:Male; D008872:Microwaves / Q000009:adverse effects* / Q000627:therapeutic use*; D008875:Middle Aged; D011859:Radiography; D012189:Retrospective Studies; D016896:Treatment Outcome
keywords: ablation; diaphragm; microwave; peripheral