title: Radiofrequency ablation in experimental bone metastases using a controlled and navigated ablation device.
abstract: BACKGROUND
  Radiofrequency ablation is a minimal invasive therapy in the treatment of bone metastases. In this study we present a new ablation system enabling an ablation in multiple directions and with an adaptable size and shape.
  
  
  METHODS
  VX-2 tumor was used for the induction of experimental bone metastases in the femur of six New Zealand white rabbits. X-ray imaging as well as CT and MRI scans before and after treatment was carried out. After detecting bone tumor, radiofrequency ablation was performed. The ablation instrument contained a 10 g bipolar, articulated extendable electrode and a proprietary generator with an impedance controlled algorithm. All bones and the soft tissue were examined histologically.
  
  
  RESULTS
  All animals developed local bone tumor. Mean duration until first osteolytic lesions on CT-scans was 48±14 days. The mean lesion area was 26 mm(2). No systemic tumor spread was seen. 6 radiofrequency procedures were carried out with a mean application time of 6 min±2:30 and an average temperature in the region of effect of 55 °C±4. MRI imaging demonstrated an ablation zone of 23±6 mm around the electrode. Histopathology showed an extensive heat necrosis with no remaining tumor cells in the ablation area.
  
  
  CONCLUSIONS
  Radiofrequency ablation is a quickly developing treatment option on the field of minimal invasive bone tumor therapy. The electrode enables an ablation adapted to size and shape of the metastases. Further clinical studies are necessary to test and enhance this radiofrequency system.
authors.affiliation: Center for Musculoskeletal Surgery, Department of Orthopaedic Surgery, University Medical Center Mainz, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Proschek
authors.affiliation: Center for Musculoskeletal Surgery, Department of Orthopaedic Surgery, University Medical Center Mainz, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Tonak
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Hospital, Frankfurt, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Zangos
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Hospital, Frankfurt, Germany.
authors.forename: M G
authors.initials: MG
authors.lastname: Mack
authors.affiliation: Center for Musculoskeletal Surgery, Department of Orthopaedic Surgery, University Medical Center Mainz, Germany; Department of Diagnostic and Interventional Radiology, University Hospital, Frankfurt, Germany.
authors.forename: A A
authors.initials: AA
authors.lastname: Kurth
keywords: Animal model; Bone tumor; Rabbit; Radiofrequency ablation; Tumor therapy; VX-2