title: Evaluation of a minimally invasive image-guided surgery system for hepatic ablation procedures.
abstract: BACKGROUND
  The Explorer Minimally Invasive Liver (MIL) system uses imaging to create a 3-dimensional model of the liver. Intraoperatively, the system displays the position of instruments relative to the virtual liver. A prospective clinical study compared it with intraoperative ultrasound (iUS) in laparoscopic liver ablations.
  
  
  METHODS
  Patients undergoing ablations were accrued from 2 clinical sites. During the procedures, probes were positioned in the standard fashion using iUS. The position was synchronously recorded using the Explorer system. The distances from the probe tip to the tumor boundary and center were measured on the ultrasound image and in the corresponding virtual image captured by the Explorer system.
  
  
  RESULTS
  Data were obtained on the placement of 47 ablation probes during 27 procedures. The absolute difference between iUS and the Explorer system for the probe tip to tumor boundary distance was 5.5 ± 5.6 mm, not a statistically significant difference. The absolute difference for probe tip to tumor center distance was 8.6 ± 7.0 mm, not statistically different from 5 mm.
  
  
  CONCLUSIONS
  The initial clinical experience with the Explorer MIL system shows a strong correlation with iUS for the positioning of ablation probes. The Explorer MIL system is a promising tool to provide supplemental guidance information during laparoscopic liver ablation procedures.
authors.affiliation: Providence Portland Medical Center, Portland, OR, USA The Oregon Clinic, Portland, OR, USA chammill@orclinic.com.
authors.forename: Chet W
authors.initials: CW
authors.lastname: Hammill
authors.affiliation: Vanderbilt University, Nashville, TN, USA.
authors.forename: Logan W
authors.initials: LW
authors.lastname: Clements
authors.affiliation: Pathfinder Technologies Inc, Nashville, TN, USA.
authors.forename: James D
authors.initials: JD
authors.lastname: Stefansic
authors.affiliation: Providence Portland Medical Center, Portland, OR, USA The Oregon Clinic, Portland, OR, USA.
authors.forename: Ronald F
authors.initials: RF
authors.lastname: Wolf
authors.affiliation: Providence Portland Medical Center, Portland, OR, USA The Oregon Clinic, Portland, OR, USA.
authors.forename: Paul D
authors.initials: PD
authors.lastname: Hansen
authors.affiliation: University of North Carolina School of Medicine, Chapel Hill, NC, USA.
authors.forename: David A
authors.initials: DA
authors.lastname: Gerber
mesh_terms: D000368:Aged; D017115:Catheter Ablation / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006498:Hepatectomy / Q000295:instrumentation* / Q000379:methods; D006801:Humans; D007430:Intraoperative Care / Q000379:methods; D010535:Laparoscopy / Q000379:methods*; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000601:surgery; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000379:methods; D011446:Prospective Studies; D018570:Risk Assessment; D025321:Surgery, Computer-Assisted / Q000379:methods*; D016896:Treatment Outcome; D018608:Ultrasonography, Doppler / Q000379:methods*
keywords: ablation; image-guided surgery; laparoscopic ultrasound; laparosopic liver surgery