title: Laparoscopic microwave ablation of human liver tumours using a novel three-dimensional magnetic guidance system.
abstract: BACKGROUND
  Accurate antenna placement is essential for effective microwave ablation (MWA) of lesions. Laparoscopic targeting is made particularly challenging in liver tumours by the needle's trajectory as it passes through the abdominal wall into the liver. Previous optical three-dimensional guidance systems employing infrared technology have been limited by interference with the line of sight during procedures.
  
  
  OBJECTIVE
  The aim of this study was to evaluate a newly developed magnetic guidance system for laparoscopic MWA of liver tumours in a pilot study.
  
  
  METHODS
  Thirteen patients undergoing laparoscopic MWA of liver tumours gave consent to their participation in the study and were enrolled. Lesion targeting was performed using the InnerOptic AIM™ 3-D guidance system to track the real-time position and orientation of the antenna and ultrasound probe.
  
  
  RESULTS
  A total of 45 ablations were performed on 34 lesions. The median number of lesions per patient was two. The mean ± standard deviation lesion diameter was 18.0 ± 9.2 mm and the mean time to target acquisition was 3.5 min. The first-attempt success rate was 93%. There were no intraoperative or immediate postoperative complications. Over an average follow-up of 7.8 months, one patient was noted to have had an incomplete ablation, seven suffered regional recurrences, and five patients remained disease-free.
  
  
  CONCLUSIONS
  The AIM™ guidance system is an effective adjunct for laparoscopic ablation. It facilitates a high degree of accuracy and a good first-attempt success rate, and avoids the line of site interference associated with infrared systems.
authors.affiliation: Department of Surgery, Carolinas Medical Center, Charlotte, NC, USA.
authors.forename: David
authors.initials: D
authors.lastname: Sindram
authors.forename: Kerri A
authors.initials: KA
authors.lastname: Simo
authors.forename: Ryan Z
authors.initials: RZ
authors.lastname: Swan
authors.forename: Sharif
authors.initials: S
authors.lastname: Razzaque
authors.forename: David J
authors.initials: DJ
authors.lastname: Niemeyer
authors.forename: Ramanathan M
authors.initials: RM
authors.lastname: Seshadri
authors.forename: Erin
authors.initials: E
authors.lastname: Hanna
authors.forename: Iain H
authors.initials: IH
authors.lastname: McKillop
authors.forename: David A
authors.initials: DA
authors.lastname: Iannitti
authors.forename: John B
authors.initials: JB
authors.lastname: Martinie
mesh_terms: D055011:Ablation Techniques / Q000295:instrumentation; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018572:Disease-Free Survival; D004867:Equipment Design; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional / Q000295:instrumentation; D010535:Laparoscopy / Q000295:instrumentation / Q000379:methods*; D008113:Liver Neoplasms / Q000473:pathology / Q000601:surgery*; D008280:Magnetics / Q000295:instrumentation / Q000379:methods*; D008297:Male; D008422:Materials Testing; D008872:Microwaves / Q000627:therapeutic use*; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D010865:Pilot Projects; D011237:Predictive Value of Tests; D011446:Prospective Studies; D025321:Surgery, Computer-Assisted / Q000295:instrumentation / Q000379:methods*; D013997:Time Factors; D014159:Transducers; D016896:Treatment Outcome; D018084:Ultrasonography, Interventional / Q000295:instrumentation / Q000379:methods*